WO2003002424A2

WO2003002424A2 - Material for temperature control

Info

Publication number: WO2003002424A2
Application number: PCT/GB2002/003002
Authority: WO
Inventors: Matthew John Searle
Original assignee: Thermotic Developments Limited
Priority date: 2001-06-29
Filing date: 2002-06-28
Publication date: 2003-01-09
Also published as: GB0116005D0; WO2003002424A3

Abstract

A packaging material incorporates a phase-change substance, which is preferably microencapsulated. The material may be formed into a container, and in some embodiments is a polymeric material. In other embodiments a pulp material is used to carry the phase-change substance.

Description

MATERIAL FOR TEMPERATURE CONTROI

The present invention relates to the use of a material for packaging, a material, a method of packaging, a container, a sleeve of material, a method of making a material and a method of forming a material.

The need to maintain substances such as foodstuffs, pharmaceuticals, human tissue and blood within a desired temperature range is well known. For example, ice-cream needs to be kept at below -10°C to prevent it from melting and many food items require conserving at between zero and 5°C. Equally it is desirable to maintain other foodstuffs at an above ambient temperature, for example take-away cooked foods.

Although refrigerators and freezers are used as appropriate to provide long term storage of foodstuffs and pharmaceuticals whose conservation depends on a desired low temperature being maintained, there is a problem in transport. For example where foodstuffs are purchased at a store remote from the location of the purchaser's refrigerator or freezer, it is necessary to take special measures to ensure the correct conditions during transport. There is a further problem where the user is not returning to a location that has a refrigerator or freezer, for example, when camping. Similar problems exist for pharmaceuticals, human or animal tissue, human or animal organs, and many other substances, products and objects for which temperature change is harmful or otherwise undesirable.

The problems noted above have been addressed in a number of ways in the past. For keeping substances, products and objects cool, one well known technique is the use of insulated containers, for example, "cool bags" or "cool boxes", which are purely passive in nature. So-called "ice packs" may be used within a cool bag or cool box to maintain a lower temperature for a longer period of time. Another technique for keeping substances, products and objects involves tne use of vacuum devices such as vacuum jugs and flasks. In addition, small portable refrigerators or freezers are available.

Similar techniques may also be used to keep substances, products and objects warm. Thus, insulated containers and vacuum devices may equally be used to keep heated things warm.

All of these solutions go some way towards overcoming the problem discussed, but all of them have their own disadvantages. For example, cool bags only protect an enclosed object for a relatively short time. To give cool conditions, the use of ice packs can extend this time but the ice packs themselves are relatively heavy and bulky. Portable refrigerators or freezers are generally expensive and inconvenient. Insulated devices for keeping things hot are again effective for only a short time.

It is an object of the present invention to seek to reduce the identified problems.

According to a first aspect of the invention there is provided use of a material incorporating a phase-change substance for packaging a substance, product or object to thereby provide temperature control of the packaged substance, product or object.

The use of a material incorporating a phase-change substance for packaging allows a substance, product or object to be fully surrounded or partially surrounded. In embodiments, the contact between the phase-change substance and the object being packaged is more intimate than where ice packs or the like are used. This means that the bulk, the weight and the cost of the packaging can be reduced. Furthermore the whole package, either with or without the substance, product or object can be readily preloaded with heat or coolth as appropriate if required. Preferably the phase-change substance is microencapsulated.

Microencapsulation provides advantages of easy handling, product stability and consistency of product manufacture.

In one family of embodiments the material comprises a non-woven fabric wherein the microcapsules of the phase-change substance are applied to at least the surface of said non-woven fabric.

Non-woven fabrics may be very thin, allowing full flexibility for easy movement. Such thin fabrics may have a surface coating of microcapsules; a higher quantity of microcapsules may be provided by plural thicknesses of fabric, each with a surface coating of microcapsules.

In another family of embodiments the material for packaging comprises a carrier material, wherein the microcapsules of the phase-change substance are supported in said carrier material.

Preferably the carrier material comprises a pulp.

The material may comprise a substrate and an adhesive securing the microcapsules to the substrate.

The material may comprise a foam and the microcapsules of the phase- change substance be disposed within the foam.

In some embodiments the material for packaging comprises at least first second and third layers, said second layer being disposed between first and thirc layers, and the phase-change substance being absorbed into the second layer. In other embodiments the material comprises at least first second and third layers, said second layer being disposed between said first and third layers, and the phase-change substance being adsorbed onto the second layer.

Preferably the phase-change of the phase-change substance is between solid and liquid.

Advantageously there are provided means for reducing heat transfer between said material and the ambient.

Conveniently there are provided plural enclosures containing air for reducing heat transfer.

According to a second aspect of the present invention, there is provided a material for use in providing temperature controlling packaging for a substance, product or object, the material being in the form of a web or sheet which incorporates microcapsules of a phase-change substance.

Embodiments of a sheet or web packaging material incorporating a phase- change substance in microencapsulated form may be readily used to wrap or pack objects. Embodiments of such a material may, where appropriate, be formed into a container for housing all or part of an object, such as another container holding a substance whose conservation is desirably in a given temperature range. Embodiments of the material may alternatively be formed into a sleeve for disposition about an object, such as a container.

By choosing a phase-change substance having a suitably high latent heat of phase-change for the application concerned, materials can maintain a temperature corresponding to that of the phase-change for a substantial period o1 time. By choosing such a substance having a phase-change at below 10°C, articles and products intended for domestic refrigeration may be kept sufficiently <-w->ι without th<=> refriπerator. Bv choosinα a substance having a phase-change sufficiently below 0°C, frozen products may be safely conserved. By choosing a substance having a phase-change at between 55 and 80°C, hot food may be kept hot enough for consumption without need to reheat. Reheating is to be avoided on a number of grounds, including inconvenience and possible contamination problems where for example bacteria may grow in lukewarm conditions.

In one embodiment, the material comprises a non-woven fabric wherein the microcapsules of the phase-change substance are applied to at least the surface of said non-woven fabric.

Non-woven fabrics may also be thick, for example in a similar fashion to felts. Such fabrics may have microcapsules within their periphery and on their surfaces.

In other embodiments, the material comprises a carrier material and the microcapsules of the phase-change substance are supported in said carrier material.

In a preferred embodiment, the carrier material comprises a pulp.

In yet other embodiments the material comprises a substrate and an adhesive securing the microcapsules to the substrate.

The substrate may be for example card, cardboard or a plastics or metal foil. in Tuπner embodiments the material comprises a foam and the microcapsules of the phase-change substance are disposed within the foam.

In another family of embodiments the material comprises at least first second and third layers of material, said second layer being disposed between said first and third layers, and the phase-change substance being absorbed into the second layer.

In a further family of embodiments the material comprises at least first second and third layers of material, said second layer being disposed between said first and third layers, and the phase-change substance being adsorbed onto the second layer.

Advantageously, the material further comprises means for reducing heat transfer from said material.

Such means may include a reflective or light surface, or a layer of insulating material. In one embodiment the packaging material comprises plural enclosures containing air for reducing heat transfer.

In some embodiments the material is sufficiently rigid to be capable of being shaped into a substantially self-supporting structure by a forming process.

Forming processes such as vacuum forming, blow or other moulding techniques may thus be used to provide a container, or an internal container to be disposed within a conventional carton or similar.

Other embodiments may provide a highly flexible material for example for wrapping purposes. According to a third aspect of the invention there is provided a method of packaging a product comprising at least partly enclosing said product using a material in accordance with the second aspect of the invention.

According to a fourth aspect of the invention there is provided a material comprising a polymer and a phase-change substance having a phase-change temperature, the arrangement being such that a container made from the said material maintains the temperature of contents of said container at said phase- change temperature.

Preferably the phase-change substance is microencapsulated.

However, the phase-change substance may alternatively be un- encapsulated, if for example mixing with the polymer material occurs at below the temperature of the phase change.

According to a fifth aspect of the invention there is provided a container having contents, the container comprising a polymer material incorporating a phase-change substance having a phase-change temperature substantially equal to said given temperature, the arrangement being such that the container maintains the temperature of said contents at said phase-change temperature.

Preferably the phase-change substance is microencapsulated.

According to a sixth aspect of the invention there is provided a sleeve of material for disposition around at least a part of a product, said material incorporating a phase-change substance for maintaining the temperature of the product at substantially the temperature of the phase-change.

According to a seventh aspect of the invention there is provided a container comprising plural walls defining a receptacle for a substance whose ifc iμeiaiun-; is to be maintained at a desired level, at least some of the walls of the container comprising a material incorporating a phase-change substance having a phase-change temperature substantially at the desired level.

Preferably the phase-change substance is microencapsulated.

In one embodiment the at least some walls comprise a non-woven material, and said non-woven material carries the phase-change substance.

According to an eighth aspect of the invention there is provided a method of making a material comprising an open-cell foam material, the foam material defining plural cells, the method comprising disposing a phase-change substance in the cells of the foam material.

According to a ninth aspect of the invention there is provided a method of making a material comprising closed-cell foam material defining plural cells, the method comprising providing a material to be foamed, and foaming the material, wherein the step of foaming includes incorporating a phase-change substance into the closed-cell foam material.

According to a tenth aspect of the invention there is provided a method of forming a material comprising providing polymer granules, providing a microencapsulated phase-change substance, blending the polymer granules and microcapsules of said phase-change substance together, and heating the blended polymer granules and microcapsules of phase-change substance to thereby form said material.

According to an eleventh aspect of the invention there is provided a method of forming a material comprising providing granules comprising polymer material and microcapsules of a selected phase-change substance, and heating the blended polymer granules and microcapsules. 1-τeτerably the method comprises injection moulding said heated blend of polymer granules and microcapsules.

Alternatively the method comprises blow moulding said heated blend of polymer granules and microcapsules.

Alternatively again the method comprises extruding said heated blend of polymer granules and microcapsules to form a web.

Preferably the method comprises stretching the web to form a film.

According to a twelfth aspect of the invention there is provided a method of packaging a product comprising providing a packaging material, and printing onto said packaging material using microcapsules of phase-change substance selected to have a phase-change temperature for maintaining said product in a desired condition.

This technique allows for items such as ice cream wrappers and yoghurt pot covers to provide a small amount of immunity from heat. Similarly printed covers and the like may be used on hot items to prevent cooling.

Exemplary embodiments of the present invention will now be described with respect to the accompanying drawings in which:-

Figure 1 shows a cross-sectional view of a portion of a woven fabric incorporating a phase-change substance;

Figure 2 shows a cross-sectional view of a portion of a non-woven fabric incorporating a phase-change substance;

Figure 3 shows a cross-sectional view of a portion of a multi-layer material with two outer layers sandwiching a layer of a phase-change substance; Figure 4 shows a cross-sectional view of a portion of a cellular cushion- type material incorporating a phase-change substance;

Figure 5 shows a modification of the embodiment of Figure 4; r-igure 6 shows a cross-sectional view of a portion of a twin-wall material incorporating a phase-change substance;

Figure 7 shows an embodiment of a foam material incorporating a phase- change substance; Figure 8 shows an enlarged view of a portion of the foam material of

Figure 6;

Figure 9 shows a perspective view of an open topped food container of a material incorporating a phase-change substance;

Figure 10 shows a perspective view of a sandwich container of a material incorporating a phase-change substance; and

Figure 11 shows a perspective view of a bottle of a polymer material incorporating a phase-change substance.

In the figures like reference numerals refer to like parts unless otherwise stated.

Referring first to Figure 1 , a woven fabric 1 consists of woven threads 2,3,4, as known to those skilled in the art. A phase-change substance 10 is held in the interstices formed by the threads of the fabric and shown illustratively in the figure. In this embodiment, the phase-change substance is a paraffin wax which is solid at the lower temperature, and the phase-change is to a liquid at the higher temperature.

Referring now to Figure 2, a non-woven fabric 60 consists of a felt-like sheet or web of fibres/ filaments 61 bonded together by mechanically entangling them. In other embodiments the fibres or filaments are entangled thermally and/or chemically. The sheet is thus flat and porous, and is made directly from separate fibres or from molten plastic or plastic film. There is no requirement to convert the fibres/filaments to yarn. The fabric shown is flexible and thin, for example 1-2 mm thick. In this embodiment, microcapsules of a phase-change substance, for example in the form of paraffinic microcapsules, are adsorbed onto the non- woven fabric.

In another family of embodiments, the fabric is thicker, for example 2cm of more. The phase-change substance is carried within the non-woven fabric, and may be absorbed into the fabric after manufacture of the fabric, or included in the fabric during its manufacture.

The choice of phase-change substance is primarily determined by the application to which the packaging is to be put. Apart from waxes and the like, one useful composition is that disclosed in US Patent 6146546 in which, by adjusting the proportions of particular component materials, a phase-change between solid and liquid can be selected across a wide range of temperatures. I will be clear to those skilled in the art that other phase-change substances may be used, including waxes and lipids.

By selecting a material having a phase-change temperature at around 10°C or lower, substances that normally require refrigeration in a domestic refrigerator can be conserved without such a refrigerator for several hours or more. By selecting a material having a phase-change at 55-80°C, food and the like can be kept hot for extended periods of time.

Turning now to Figure 3, a sheet packaging material 20 consists of two outer layers 21 ,22, sandwiching a fabric 23. The outer layers 21 ,22 may be polyester, polypropylene, polyvinyl chloride, PET or another polymeric or non- polymeric material selected according to the constraints of the application to which the packaging material is to be put. More particularly, the skilled person will select materials for the outer layers according to the intended temperature o1 use, and according to the strength needed. One preferred embodiment uses pulp materials for one or both outer layers, as this allows forming by a number o inexpensive techniques, as well as providing both mechanical and thermal insulation.

The fabric 23 carries a phase-change substance and may be woven as described with reference to Figure 1 herein or non-woven as described with reference to Figure 2 herein.

If the phase-change substance is not micro-encapsulated and changes phase from solid to liquid, the material of the outer layers 21 ,22 may be selected to contain liquid within the sandwich formed by the outer layers 21 ,22.

In one family of embodiments, the sheets are sealed together to form a quilted type of structure. The fabric 23 may be continuous through the regions where the sheets 21 ,22 are sealed together or may only be disposed within the spaces formed between the sealed regions.

The arrangement shown in Figure 3 can be used either way round, in other words either the sheet 21 may be remote from the material being packaged or sheet 22 may be remote from it. It is also clear to those skilled in the art that additionally an insulating material may be provided on one of the faces of the packaging material 20 in which case the uninsulated side would be in proximity to the material being packaged.

Figure 4 shows another embodiment of a packaging material in accordance with the invention. The packaging material 30 of Figure 4 is somewhat similar to known air cellular cushioning material, consisting of two webs of plastics, such as polyethylene, which are welded together at intervals to define bubble-shaped spaces. The spaces 33 contain a phase-change substance.

The particular configuration shown in Figure 4 is asymmetrical as the lower sheet 31 is shown in a generally planar configuration, with the upper sheet 32 extending away from it to define the container spaces 33. Other arrangements are possible. Specifically a symmetrical construction, in which the "bubbles" extend both upwardly and downwardly from the intermediate web portions, is also envisaged.

Turning now to Figure 5, a modification of the packaging material of Figure 4 is shown. The packaging material 40 of Figure 5 has an arrangement similar to that described with respect to Figure 4 but with the generally planar face of the lower (as shown) sheet 31 in contact with an insulating layer 41. The layer 41 may consist of a pulp material, such as paper pulp, a foam material, for example polystyrene foam material, or alternatively it may consist of a double-walled structure containing air, or indeed a vacuum, to provide reduced transfer of heat to the ambient.

A further embodiment is shown in Figure 6. Referring to Figure 6, a corrugated web of plastics material 51 is disposed between upper and lower (as shown) plastics sheets 52,53. The upper and lower sheets 52,53 contact respectively the peaks and troughs of the corrugations of the web 51 so as to sandwich the web and to define lower compartments 54 between the web and the lower sheet 53 and upper compartments 55 between the web and the upper sheet 52. The particular profile of corrugation shown in Figure 6 is a generally triangular or saw-tooth configuration. It will be understood by those skilled in the art that other corrugation profiles could be provided, for example curved profiles.

In the lower compartments 54 there is disposed a phase-change substance whereas the upper compartments 55 contain air to provide insulation. It will be clear to those skilled in the art that the lower sheet 53 will be proximate a product or substance to be kept cool or hot with the upper sheet 52 proximate the ambient. It would also be possible to provide a foam or other insulating structure on the upper sheet 52. In another embodiment, the packaging material consists of first and second opposed sheets which sandwich a third layer. The third layer defines, together with the first sheet, a plurality of first prisms containing the phase- change substance, for example pyramids. The third layer further defines, with the second sheet, a plurality of second prisms that contain air.

It will be understood that shapes other then pyramids could be used, although it may be desirable that the faces of the prisms on the first sheet tessellate so as to leave no gaps on the first sheet.

In the above embodiments, the phase-change substance may be microencapsulated, or not according to the desired application.

In another embodiment, the phase-change substance, in microcapsule form, is disposed on the surface of a web, for example a metal foil. A technique for doing this may be a type printing process; the microcapsules may be coloured. The resulting product is useable for sealing articles such as yoghurt pots, or for wrapping ice creams and the like.

In another embodiment, not illustrated, the phase-change substance is incorporated into a polymer packing film or a product such as a bottle or other container made of a polymer material. The phase-change substance may be microencapsulated.

To make a packaging material or package from a polymer carrying a phase-change substance, the granules of polymer are either pre-blended with the microcapsules of phase-change substance or the polymer granules are mixed with^' the microcapsules of phase-change substance for blending. The granules are then heated to the required temperature and either fed to an extruding device or to a moulding device as appropriate. It is also possible to blend the granules of polymer material with the phase-change substance without micro-encapsulation, for example if the blending is below the phase-change temperature.

If a film is to be made, the polymer is extruded, with the microcapsules of phase-change substance carried in it, and then the film is formed by stretching in the usual way. Depending on the required characteristics of the material it may be either monoaxially or biaxially stretched.

To make a bottle or other container, injection moulding, blow moulding, vacuum forming or a combination of these, may be employed.

The microcapsules of the phase-change substance may alternatively be supported in a carrier material. The carrier material may include an adhesive for securing the microcapsules to a substrate such as cardboard or a plastics web.

The carrier material may be a conventional packaging material such as card.

Referring to Figure 7, a foam material 60 comprising open cells is impregnated with the phase-change substance. Typically, the phase-change substance will be provided in a liquid form to allow it to be soaked into the foam or adsorbed into the cells of the foam so that when the foam is cooled, the phase-change substance becomes solid. The area 61 of the foam is an exemplary portion of the foam which is shown more clearly in Figure 8. Referring to Figure 8, it will be seen that the foam has a three dimensional structure of cellular walls 71 which define, here open cells 72, the open cells 72 containing the phase-change substance.

It will be clear to those skilled in the art that a similar arrangement can be provided where the foam is a closed cell material. In this case however it is necessary to provide the phase-change substance during the manufacture of the foam since the closed cellular nature would prevent the phase-change substance entering tne cells after manufacture. One method of such manufacture is to use the phase-change substance as part of the foaming process.

Whether the foam is open or closed cellular, the material constituting the foam may contain microencapsulated phase-change substance. The microcapsules may be the sole presence of the phase-change substance, or there may be an additional presence of the phase-change substance in the cells of the foam.

It will be appreciated that the packaging materials described may be provided in either a substantially flexible or a substantially rigid form. The choice will largely depend upon the needs of the device, object or substance that is being packaged.

It is envisaged that where a substance such as ice cream is being packaged, the packaging material of the invention could be used as the primary packaging of the ice cream. By "primary packaging" it is meant that the icecream itself would be in contact with the packaging material rather than an intervening wrapping or packaging being provided. Under other situations, for example where a pre-existing container were provided, then it would be possible either to use the packaging material as an external package purely for the sake of thermal conditions, or alternatively to use the packaging material additionally to provide protection for the object being packaged. The embodiments of Figures 5,6 and 7 would be suitable for this.

Another application of the invention is in the field of take-away foods, for example for either hot snacks or cold perishable foods. Outlets with buffet or like self-service areas are popular, for instance for take-out lunches or for taking away pre-prepared chilled or hot foods. A food container 90 for such applications is shown is shown in Figure 9. It consists of a moulded plastics generally cylindrical open container with a circular base wall 91 and a generally cylindrical sidewall extending from the base wall at a draft angle suitable for moulding. The piastics material of the container incorporates a phase-change substance to provide a desired temperature maintenance. A lid of the same material may be provided.

By providing a sales area with a stack of containers incorporating a low temperature (e.g. 10°C or less) phase-change substance, and by keeping the stack being kept in an environment with a temperature below the phase-change temperature, cold or chilled products may be self-served or served by counter staff, with the knowledge that the food will be maintained at a satisfactory temperature for prolonged time periods of several hours or more.

A similar stack of containers but having high temperature phase-change substances (e.g. 55-80°C) and kept in a heated area with a temperature above the phase-change temperature can likewise enable heated food to be dispensed.

The invention is not restricted to containers of polymer materials or to containers having any particular wall structure. The container may have other material structures - for example similar to the material described with reference to Figure 5 or 6, and may additionally have an insulating layer or sleeve.

Pre-packed food - e.g. sandwiches may be packed in containers made to incorporate appropriate phase-change substances, and stored at the appropriate high or low temperature. A suitable container 100 is shown in Figure 10, and is made from a material similar to that shown in Figure 5, by a vacuum forming process. It has walls 101-104 and a hinged front wall 105, and is dimensioned to receive a diagonally cut sandwich. Other examples may have no hinged wall, but instead be closed by sealing a suitable sized portion of plastics web over the aperture of the box. The web may incorporate a phase-change substance.

In all situations it may be advantageous to include an insulation portion, for example a label or outer coating. This may be of particular importance if the Tooα is very not, to avoid injury. A reflective inner or outer coating may be included where desirable.

Figure 11 shows a bottle 110 of polymer material incorporating a phase- change substance as described herein for keeping a drink cool. The bottle is otherwise conventional.

Embodiments e.g. that of Figure 4, or the monoaxially stretched polymer carrying the phase-change substance, may be provided as a heat-shrink material, at the same time possibly affording protection due to the bubbles. Such a heat-shrink packaging material could be applied to a pre-existing package and then heat applied to shrink to the pre-existing package.

Further applications of the packaging material described above are the provision of sleeves from the material, for example sized to be disposed about a bottle or can or over a pack of sandwiches to keep the sandwiches at a constant temperature. The sleeve, or a container made of or including the packaging material may be dimensioned to receive a chilled food container, thereby keepinc the food at a desired and safe temperature until it is heated prior to consumption. Packages may also be used to protect biological material, such as human tissue for use in surgical processes, and including blood. A container made of or from the packaging material may be dimensioned to receive a chilled food product which incorporates a self-heating device. In such an arrangement the food or the chilled food product is maintained at a predetermined temperature - not necessarily for the preservation of the food itself, but so that the self-heating device will always be required to operate from the same basic temperature. This means that the self-heating device achieves the desired effect on the food without drying out or otherwise deleterious effects.

In embodiments where the phase-change substance is not microencapsulated, it may include a gelling agent to reduce the effect of spillage Another advantageous container is a multi-compartment array made from foam or polymer material including the phase-change substance, each of the compartments being specially adapted to receive a vial, bottle or other container of pharmaceutical or biological material. This is of particular interest for transport of blood samples, vaccines and the like.

Embodiments of containers in accordance with the invention may be made to be rugged and to provide physical protection to their contents. Food containers are, in some embodiments, made to be single use - but it is envisaged that even single use containers could be re-used a few times by the consumer, in a similar way to ice-cream containers. In other embodiments, the containers are made for permanent re-use, similar to cool boxes.

It should be borne in mind that any phase-change substance might be used according to the desired conditions. Specifically, it is envisaged to use waxes, lipids and fats where appropriate, and also to use materials that change phase between liquid and gas, or which sublime from solid to gas.

Embodiments of the present invention have been described with particular reference to the examples illustrated. However, it will be appreciated that variations and modifications may be made to the examples described within the scope of the present invention.

Claims

1. Use of a material incorporating a phase-change substance for packaging a substance, product or object to thereby provide temperature control of the packaged substance, product or object.

2. Use of a material according to Claim 1 , wherein the phase-change substance is microencapsulated.

3. Use of a material according to Claim 2, comprising a non-woven fabric wherein the microcapsules of the phase-change substance are applied to at least the surface of said non-woven fabric.

4. Use of a material according to Claim 2, comprising a carrier material, wherein the microcapsules of the phase-change substance are supported in said carrier material.

5. Use of a material according to Claim 4, wherein the carrier material comprises a pulp.

6. Use of a material according to Claim 4, wherein the material comprises a substrate and an adhesive securing the microcapsules to the substrate.

7. Use of a material according to Claim 2, wherein the material comprises a foam, and the microcapsules of the phase-change substance are disposed within the foam.

8. Use of a material according to Claim 1 or 2, wherein the material comprises at least first second and third layers, said second layer being disposed between first and third layers, and the phase-change substance being absorbed into the second layer.

9. Use of a material according to Claim 1 or 2, wherein the material comprises at least first second and third layers, said second layer being disposed between said first and third layers, and the phase-change substance being adsorbed onto the second layer.

10. Use of a material according to any preceding claim, wherein the phase- change of the phase-change substance is between solid and liquid.

11. Use of a material according to any preceding claim, comprising means for reducing heat transfer between said material and the ambient.

12. Use of a material according to any preceding claim, comprising plural enclosures containing air for reducing heat transfer.

13. A material for use in providing temperature controlling packaging for a substance, product or object, the material being in the form of a web or sheet which incorporates microcapsules of a phase-change substance.

14. A material according to Claim 13, comprising a non-woven fabric wherein the microcapsules of the phase-change substance are applied to at least the surface of said non-woven fabric.

15. A material according to Claim 13, comprising a carrier material, wherein the microcapsules of the phase-change substance are supported in said carrier material.

16. A material according to Claim 15, wherein the carrier material comprises a pulp.

17. A material according to Claim 15, comprising a substrate and an adhesive securing the microcapsules to the substrate.

18. A material according to Claim 13, wherein the material comprises a foam and the microcapsules of the phase-change substance are disposed within the foam.

19. A material for use in providing temperature controlling packaging for a substance, product or object, the material being in the form of a web or sheet which comprises at least first second and third layers of material, said second layer being disposed between said first and third layers, and a phase-change substance absorbed into the second layer.

20. A material according to any of Claims 13 to 19, comprising means for reducing heat transfer between said material and the ambient.

21. A material according to any of Claims 13 to 20, comprising plural enclosures containing air for reducing heat transfer.

22. A method of packaging comprising at least partly enclosing a substance, product or object with a material in accordance with any one of Claims 13 to 21.

23. A material comprising a polymer and a phase-change substance having a phase-change temperature, such that a package made from the said material is useable to maintain the temperature of contents of said package at said phase- change temperature.

24. A material according to Claim 23 wherein the phase-change substance is microencapsulated.

25. A container having contents, the container comprising a polymer material incorporating a phase-change substance having a phase-change temperature, the arrangement being such that the container maintains the temperature of said contents at said phase-change temperature.

26. A container according to Claim 25, wherein the phase-change substance is microencapsulated.

27. A sleeve of material for disposition around at least a part of a product, said material incorporating a phase-change substance having a phase-change temperature, for maintaining the temperature of the product at substantially said phase-change temperature.

28. A container comprising plural walls defining a receptacle for maintaining the temperature of a substance at substantially a desired level, at least some of the walls of the container comprising a material incorporating a phase-change substance, wherein the temperature of phase-change is substantially the desired level.

29. A container according to Claim 28, wherein the phase-change substance is microencapsulated.

30. A container according to Claim 28 or 29, wherein the at least some walls comprise a non-woven material, and said non-woven material carries the phase- change substance.

31. A container for keeping foodstuffs hot comprising a container according to any of Claims 28 to 30, wherein the temperature of phase-change is above 50°C.

32. A container for conserving foodstuffs comprising a container according to any one of Claims 28 to 30, wherein the temperature of phase-change is 5°C or lower.

33. A method of making a material comprising an open-cell foam material, the foam material defining plural cells, the method comprising disposing a phase- change substance in the cells of the foam material.

34. A method of making a material comprising closed-cell foam material defining plural cells, the method comprising providing a material to be foamed, and foaming the material, wherein the step of foaming includes incorporating a phase-change substance into the closed-cell foam material.

35. A method of forming a material comprising: providing polymer granules, providing a phase-change substance; blending the polymer granules and said phase-change substance together, and, heating the blended polymer granules and phase-change substance to thereby form said packaging material.

36. A method of forming a material comprising: providing granules comprising polymer material and a selected phase- change substance, and, heating the blended polymer granules and the phase-change substance.

37. Preferably the phase-change substance is microencapsulated.

38. A method according to Claim 35, 36 or 37, comprising injection moulding said heated blend of polymer granules and phase-change substance.

39. A method according to Claim 35, 36 or 37, comprising blow moulding said heated blend of polymer granules and phase-change substance.

40. A method according to Claim 35, 36 or 37, comprising extruding said heated blend of polymer granules and phase-change substance to form a web.

41. A method according to Claim 40, comprising stretching the web to form a film.

42. A method of packaging a product comprising providing a packaging material, and printing onto said packaging material using microcapsules of phase-change substance selected to have a phase-change temperature for maintaining said product in a desired condition.