WO1988010214A1

WO1988010214A1 - Improved packaging

Info

Publication number: WO1988010214A1
Application number: PCT/AU1988/000209
Authority: WO
Inventors: Richard J. Lloyd; Ambrose Patrick Coad
Original assignee: Transpak Pty. Ltd.
Priority date: 1987-06-24
Filing date: 1988-06-24
Publication date: 1988-12-29

Abstract

A system and method of packaging goods that are sensitive to variations in temperature, humidity or atmospheric deterioration. In one form the packaging system comprises a relatively rigid container (10) made of, for example, fluted cardboard, having a flexible liner (12) of composite material bonded to the inner surface of the container. The composite material consists of a reflective skin (14) made of, for example, metallized polythene and thermal insulating material (16) made of, for example, open-celled plastic foam. An additional liner bag (18) of moisture impervious material may be included to protect the contents from variations in humidity and atmospheric deterioration. In a second form of the packaging system the flexible liner is in the form of a bag (24) constructed from a similar composite material comprising a reflective outer skin (26), a moisture impervious inner skin (28) and a thermal insulating material (30) therebetween. A unique method of folding the liner bag (24) and the container (10) is also described which enables the two components of the packaging system to interlock.

Description

IMPROVED PACKAGING Field of the Invention

The present invention relates to a system and method of packaging goods that are sensitive to variations in temperature or humidity or to atmospheric deterioration. In the packaging of fresh or frozen goods, such as fresh meat or frozen fish, it is common practice to package, transport or store the produce in cartons made from fibreboard, plastics or other rigid or semi-rigid packaging material. These forms of packaging suffice when the goods are stored for a short period of time and are not subject to rapid variations in temperature. Even so, food stored or in transit in this kind of packaging is susceptible to rapid deterioration even when subject to only slight increases in temperature due, for example, to exposure of the packaging to direct sunlight. A need exists for an improved system of packaging goods that are sensitive to variations in temperature, which would enable such goods to be stored for extended periods of time, and which is able to protect such goods from variations in temperature or humidity, or to atmospheric exposure that would cause deterioration.

Description of the Prior Art

Existing packaging techniques employ fibreboard boxes, or containers made from plastics materials or styrofoam which relay on the insulating properties of the material to provide thermal protection for the contents of the containers. Such known containers generally provide adequate protection for heat transmitted through conduction, however they have limited utility in . • ' providing protection for heat transmitted by convection and/or radiation. Furthermore such known containers are generally of low durability being easily damaged during handling.

The present invention was developed with the view to providing an improved packaging system and method of packaging perishables and other goods that are sensitive to variations in temperature.

Statement of the Invention

According to one aspect of the present invention there is provided a packaging system for packaging goods that are sensitive to variations in temperature, the system comprising: a relatively rigid container for containing said goods; and a flexible liner constructed of composite material including a reflective skin and a thermal insulating material bonded thereto whereby, in use, the flexible liner enhances the thermal insulating properties of the container so that goods held therein can be protected more effectively from variations in temperature.

According to another aspect of the present invention there is provided a flexible liner bag for use in a packaging system for packaging goods that are sensitive to variations in temperature, the liner bag being constructed from a composite material including a reflective outer skin and a thermal insulating material bonded thereto, and being adapted for lining a relatively rigid container to enhance the thermal insulating properties of said container, said liner bag being provided with crease marks therein adjacent a bottom portion of the bag whereby said crease marks enable said bottom to be readily folded to form a substantially .flat base section, adapted to fit in the,base of said container, and to form two folded sections adapted to interlock with said container whereby, in use, said liner bag can be more securely retained in said container by the interaction of said folded sections interlocking with said container.

According to a still further aspect of the present invention there is provided a method of packaging goods that are sensitive to variations in temperature, the method comprising: lining a relatively rigid container with a flexible liner wherein said liner is constructed of composite material including a reflective skin and a thermal insulating material bonded thereto; placing said goods within the lined container; and - . -

closing the container whereby, in use, said flexible liner enhances the thermal insulating properties of the container so that goods held therein can be protected more effectively from variations in temperature.

Preferably said composite material further comprises a moisture impervious skin, the composite material having the thermal insulating material provided between the reflective skin and the moisture impervious skin.

Brief Description of the Drawings

In order that the nature of the invention can be better ascertained, preferred embodiments of the packaging system and method of packaging will now be described, by way of example only, with reference to the accompanying drawings, wherein:

Figure 1 illustrates schematically in section view a first embodiment of the packaging system;

Figure 2 illustrates schematically in section view a second embodiment of the packaging system;

Figure 3 illustrates schematically in section view a third embodiment of the packaging system;

Figure 4 illustrates schematically the system of Figure 3 including an absorbent polymer based module; Figure 5 illustrates a section view through one example of a composite material used for the liner bag of Figures 3 and 4;

Figures 6(a) and 6(b) illustrate a section view and a plan view respectively of a second example of a composite material used for the liner bag;

Figure 7 illustrates schematically a liner bag with valve system;

Figures 8(a) and 8(b) illustrate schematically in section view the arrangement and operation of one embodiment of a one-way valve system; Figure 9 illustrates in section view the arrangement of one embodiment of a two-way valve system;

Figures 10(a) and 10(b) illustrate the position of a sleeve and of crease marks provided in the liner bag;

Figure 11 illustrates the liner bag of Figure 10 in its folded position;

Figure 12 illustrates an alternative method of creasing the liner bag; and Figures 13(a), 13(b) and 13(c) illustrate the manner of folding one embodiment of the container and its interaction with the liner bag of the packaging system.

Detailed Description of the Preferred Embodiments Referring to Figure 1 there is shown a relatively rigid container 10 that consists of a box made from fibreboard, plastic or other substantially rigid or semi-rigid material suitable for the application in view. Preferably the box 10 is made of fluted material, such as corrugated fibreboard or cardboard to provide rigidity and to create an air barrier providing additional insulation for the contents of the container. A liner made of composite material 12 is bonded to an inner surface of the container 10 to enhance the thermal insulating properties of the container 10. In the first embodiment of the packaging system illustrated in Figure 1, the composite material 12 consists of a reflective skin 14 and a thermal insulating material 16 which are preferably laminated to the inner surface of the container 10 with the thermal insulating material 16 located between the reflective skin 14 and the inner surface of container 10. An additional optional liner bag 18, made from a flexible, moisture impermeable material, is received in the container 10. Liner bag 18 can be hermetically sealable to protect the contents of the container from variations in humidity and to prevent spillage of the liquid contents of the container.

The packaging system without the liner bag 18 5 need not necessarily be waterproof as it is designed primarily to provide thermal insulation. The thermal insulating material 16 provides a barrier which inhibits heat from being transmitted to the contents of the container 10 by conduction, whereas the reflective skin

10 14 reflects heat which may be transmitted to the container 10 by radiation or convection.

The system also inhibits the conduction and radiation of heat from within the container outwards. The packaging system according to the invention therefore

15 has superior thermal retardant qualities compared to known packaging systems.

Figure 2 illustrates a second embodiment of the packaging system which is similar to the system illustrated in Figure 1 except that the container lQ.is

20 provided with, an additional reflective skin 20 bonded to the outer surface thereof. With this embodiment of the packaging system the contents of the container 10 are also protected from radiant heat transmitted from outside the container, and any heat which is not reflected must

25 then penetrate the thermal barrier afforded by the fluted packaging material 22 of the container 10 as well as the thermal insulating material 16 and the reflective skin 14 on the innermost surface of the system. A variation of this second embodiment of the packaging system, involves

30 using an ordinary plastics material as a liner on the interior of the container instead of the inner reflective skin 14. As in the first embodiment, an optional liner bag made of moisture impermeable plastics material, may also be incorporated in the system to provide protection 35 from variations in humidity and to prevent the spillage of moisture from the contents of the container. The reflective skin 14 used in the improved packaging system may be a reflective metal foil, or a metallized polythene or polyester film. The thermal insulating material 16 may be a rubberized extruded foam material such as a cross-linked polyethylene foam.

Preferably, the thermal insulating material employed in this invention is an open-celled plastic foam a-s opposed to close-celled foam. The reflective skin 14 is preferably laminated to the thermal insulating material 16, and the composite material thus formed can then be laminated or otherwise fixed to the rigid packaging material used to form the container 10. Lamination takes place during the manufacturing process of the container 10 and may be done during the rolling process of the packaging material from which the container is constructed, such as the fluted cardboard material, or during the forming process of the container 10 in which the rigid material is folded or otherwise formed into the desired shape of the packaging system. In Figure 3 a third embodiment of the packaging system is illustrated schematically in section view. In this embodiment, a flexible liner bag 24 is provided within the container 10 and is constructed of a composite material, similar to that used in the liner described above, comprising a reflective outer skin 26 and a moisture impervious inner skin 28 provided with a thermal insulating material 30 therebetween. The liner bag 12 is hermetically sealable at 32 to ensure controlled humidity and temperature conditions within the bag. Goods can be stored in the container 10 and the liner bag 24 when sealed for a substantially longer period than is possible with goods stored in the container alone. The reflective outer skin 24 acts to reflect heat away from the contents of the bag 24, while the inner skin 28 inhibits the entry of moisture into the liner bag and spillage of liquids from within the liner bag. The insulating material 30 provided between the inner and outer skins of the liner bag 24 further inhibits heat from passing through the walls of the bag. The liner bag 24 therefore protects the goods held therein from rapid variations in temperature and/or humidity more effectively than if the goods were held in the container 10 alone.

Figure 4 illustrates schematically the system of Figure 3 including an absorbent base module 34. Base module 34 comprises a polymer material which can be placed in the base of the liner bag 24 or of container 10, in a dry or wet frozen state if desired, and can be covered with a shield 36 of plastic or other rigid material to prevent the contents of liner bag 24 from contacting with the polymer material. The provision of the absorbent base module 34 within the liner bag in a frozen state helps to maintain goods stored in the liner bag at a reduced temperature. This embodiment of the packaging system is particularly advantageous for packaging of wet, iced or cold goods. The base module 34 may also be provided in a dry state, together with ice packed within the liner bag, the polymer material of the base module absorbing liquid from the ice as it melts so that the goods are not contaminated or saturated with liquid upon arrival. Figures 5 and 6 illustrate two different forms of the composite material used for constructing the liner bag 24 in Figures 3 and 4. In Figure 5 there is illustrated a section of laminate material comprising a metallized polyester outer skin 38 and a polythene inner skin 40 having a foam plastic insulating material 42 provided therebetween. The insulating properties of the laminate material for the liner bag 24 may be further increased by using a plastics air-cell insulating material 44 as illustrated in Figure 6. A liner bag constructed from the composite materials illustrated in

Figures 5 and 6 may be conveniently sealed by the application of heat and pressure to weld the polythene inner skin 26 together. Alternatively, the walls of the liner bag may be bonded together along the opening of the bag by the application of bonding tape, Velcro tabs or some other adhesive. Clearly, the composite material need not be a laminated, and may comprise an outer skin and an inner skin with an insulating material held loosely therebetween. An advantage of the laminate material illustrated in Figures 5 and 6, having an open-celled foam plastics thermal insulating material, is that the composite material thus formed has excellent thermal insulating characteristics whilst retaining a high degree of flexibility.

The liner bag 24 may be constructed from a single piece, or several pieces, of composite material cut and folded to the appropriate size with each of the seams sealed or bonded together appropriately. Gussets may also be included in the base and/or walls of the bag to enable storage of the bag in a flat folded condition and allowing it to be opened to a shape corresponding to the general shape of the container 10. A particular advantageous technique of folding the liner bag 24 will be described in detail below with reference to Figures 10, 11 and 12. Referring now to Figure 7 there is illustrated an embodiment of a liner bag 24 provided with a skirt 46 preferably made of thermoplastic material, for example, polythene or nylon material, extending from the mouth of the bag 24. The skirt 46 is typically made from polythene or nylon material which is welded to the inside of the mouth of the liner bag 24, and which enables the bag 24 to be hermetically sealed by heat sealing. An alternative system of sealing the liner bag 24 involves the use of Velcro material bonded to the inside surfaces of the mouth of the liner bag which can be pressed together to seal the bag in situations where a hermetic seal is not essential. Figure 7 also illustrates a valve system 48 preferably provided in the skirt 46, although it may also be provided directly in the wall of the bag 24. Valve system 48 is incorporated in the liner bag 10 to enable atmospheric gases trapped in the bag after sealing to be evacuated to aid in preserving the contents of the bag, and to prevent atmospheric gases from re-entering the bag. Figure 8 illustrates schematically in section view the arrangement and operation of one embodiment of a one-way valve system.

Referring to Figure 8(a) there is shown a one-way valve means 50 comprising a body 52 incorporated in the wall of the liner bag, provided with an orifice 54 and a closure element 56 for opening and closing the orifice 54. Orifice 54 enables gases to communicate through the body 52 from the interior of the bag to the exterior of the bag, and closure element 56 is movable between an open position to allow gases to pass through to the exterior of the bag and a closed position to .. prevent gases from passing through orifice 54 to the interior of the bag. Figure 8(a) illustrates the one-way valve means 50 with the closure element 56 in the open position, whereas Figure 8(b) illustrates the valve means 50 with the closure element 56 in the closed position. Closure element 56 is normally resiliently biased in the closed position, so that the bag can be evacuated either by applying a vacuum to the exterior portion of the valve means 50 or by external compression of the liner bag forcing the gases trapped inside after sealing to escape through the orifice 54 of valve means 50. The removal of untreated atmospheric gases from the interior of the liner bag can be important for the preservation of certain perishable food products, where contamination or decomposition is accelerated by exposure to uncontrolled atmospheric gases (air). The closure element 56 prevents air passing back through the valve means 50 into the liner bag.

In Figure 9 a two-way valve means 58 is illustrated, which allows atmospheric gases to be released in a similar manner to that described above, but also allows a modified gas or gases to be injected into the liner bag through a separate orifice within the valve means 58. The two-way valve means 58 comprises a body 60 having a first orifice 62 and a second orifice 64, and first and second closure elements 66 and 68 for closing said first and second orifices respectively. The first orifice 62 enables gases to communicate from the interior of the bag to the exterior and the second orifice 64 enables gases to communicate from the exterior to the interior of the liner bag. The first closure element 66 is movable to an open position (as shown) to allow gases to pass through to the exterior of the bag and is movable to a closed position to prevent gases from entering .the first orifice 62 to the interior of, the bag. The second closure element 68 is movable to an open position to allow gases to pass through to the interior of the bag and movable to a closed position to prevent gases from passing through the second orifice 64 to the exterior of the bag.

The liner bag is evacuated of atmospheric gases in a similar manner to that described with reference to Figure 8, and then a sealing means 70 is fastened to the external portion of the valve means 54 to seal the valve means whereby gases cannot escape through the first orifice 62 to the exterior of the bag. A modified gas or gases can then be injected through the second orifice 64 to the interior of the bag and closure element 68 prevents gases from passing through the second orifice to the exterior of the bag. Sealing means 70 illustrated in Figure 9 is in the form of a cap which clips onto the external portion of the two-way valve means 58. In both embodiments of the valve means illustrated in Figures 8 and 9 the closure elements are similar to flap valves, however the invention is clearly not limited to this kind of valve structure and may employ alternative valve arrangements, for example ball valves. The valve systems illustrated in Figures 8 and 9 are in no sense intended to be limitive of the kind of valve system that may be employed in the present invention, but are merely illustrative of a simple form of valve system which can be manufactured from moulded plastic and incorporated in the wall of a liner bag in accordance with this invention. Figure 10 illustrates a further optional feature of the present invention comprising a sleeve 72 provided in liner bag 24 and adapted to receive a cooling means (not shown) such as ice or an ice pack which is inserted prior to sealing or closing of liner bag 24. Advantageously, sleeve 72 is also of polythene and is bonded to the mouth of liner bag 24 together with skirt 46.

Figure 10(b) illustrates in section view the location of sleeve 72 in relation to skirt 46 showing how an ice pack or other cooling means can be inserted in the direction of the arrow between the sleeve and the skirt, and sealed therein simultaneously with the sealing of skirt 46. The provision of cooling means within the liner bag 10 can further aid in preserving the contents of the bag during transport.

Figure 10(a) also illustrates the position of crease marks 74 on liner bag 24 in its unfolded condition. Crease marks 74 are provided adjacent a bottom portion 76 of the bag and enable the bottom portion 76 of liner bag 24 to form a substantially flat base section 80 and two folded sections 82 as illustrated in Figure 11.

Liner bag 24 is typically constructed from a rectangular sheet of the composite material, folded in half and sealed along two edges 78 to form a bag that lies flat in its unfolded condition. Preferably, the crease marks 74 comprise first and second crease marks extending substantially perpendicularly to a side edge 78 and the bottom portion 76 of the bag respectively at both bottom corners of the bag. The length of the crease marks 74 is significant because it determines the width of the base section 80 of the liner bag in its folded condition. Crease marks 74 can be applied to the composite material of liner bag 24 by the application of heat and/or a compressive force to both sides of the liner bag to allow it to be folded for assembly as shown in Figure 11.

Figure li is an enlarged view of one corner of the liner bag 24 of Figure 10 in its folded condition.

With the liner bag folded along crease marks 74, a folded section 82 is formed of triangular shape, which is flattened and folded upwards to overlap the side edge 78 of the liner bag 24. Crease marks 74 also ensure that a substantially flat base section 80 is formed in the bottom portion of the liner bag 24 which is adapted to fit in a base of a rigid or semi-rigid container with which the liner bag 24 can be combined to form a complete packaging system. The liner bag 24 can be securely retained in the container by the action of the folded sections 82 interlocking with the container in a manner to be described in greater detail below. Figure 12 illustrates an alternative method of folding a liner bag 24 to form the folded section 82 and base section 80. In this method a single line crease is applied across both bottom corners of the liner bag to achieve substantially the same result.

Figure 13 illustrates the manner of folding one embodiment of the container used in conjunction with the liner bag in the packaging system. Referring to Figure 13(a) there is shown one end of a container 84 constructed from a single semi-rigid sheet of planar material folded to form a rectangular box structure. The planar material employed is preferably a fluted fibreboard material as previously described. A side wall 86 of the box is formed by folding the planar material along folds 88 in such a manner that the folds form an inverted V-shaped intrusion on an interior surface of the side walls. When side wall 86 is folded upwards in the direction of arrow A as shown in Figure 13(a), the resultant wall of the container 84 is three layers thick over a significant portion of the area of the side wall. Figure 13(b) illustrates the side wall 86 in its folded condition viewed from inside the container 84 and illustrates how the folds 88 form an inverted V-shaped intrusion on the interior surface of the side wall. Forming the container 84 in the above manner has a number of advantages. Firstly, the triple thickness of the side wall 86 greatly increases the strength of the container 84. Secondly, the folds 88 forming the inverted V-shaped intrusions ensure that the container 84 is water-tight at least up to the level of the apex 90 of the inverted V-shaped intrusions. Thirdly, the inver.ted V-shaped intrusions provide indented portions within the container 84 for receiving the folded sections 82 of a liner bag used for lining the container 84. The triangular shaped folded sections 82 of liner bag 24 illustrated in Figure 11 are designed to fit within the inverted V-shape intrusions at both ends of container 84 so that the liner bag can be securely retained in the container by the interaction of the folded sections 82 with the container side walls. The interaction of the liner bag 24 with the container 84 is illustrated in Figure 13(c) which illustrates schematically the respective components of the packaging system in section view. The base section 80 of liner bag 24 is received within the container 84 and the folded section 82 is received within the indented portion of side wall 86 of container 84, provided by the inverted V-shaped intrusion formed by the folds 88 as shown in Figure 13(b) . The interlocking of liner bag 24 with container 84 ensures that the two components do not become detached during packing, and also provides additional stability during transit. The locking effect between the components also has the advantage of maintaining the distances between the two components to maximize the thermal insulating properties inherent in- both components of the packaging system. The locking effect can also provide additional shock absorption in the event of an end-on impact.

Container 84 is preferably manufactured from fluted fibreboard such as, for example, corrugated cardboard, to provide an additional air barrier between the container contents and the environment. Container 84 can also be impregnated or coated with a moisture impervious material to prevent fluids from penetrating from the outside or from leaking from within. A significant advantage of employing the above kind of container constructed from a single sheet of semi-rigid planar material, which can be folded to form a rectangular box, is that the complete packaging system, including the liner or liner bag, can be stored in a flat condition before and after use, unlike present insulating packaging which is formed of styrofoam, or ordinary cartons which do not have the superior insulating properties of the present system and method of packaging. In the above preferred embodiment, the indented portions on the interior of the side walls 86 of container 84 are provided by folding the sheet of material from which container 84 is constructed in such a manner as to form the inverted V-shaped intrusions as described. However, the container 84 can also be constructed by alternative methods and provided with indented portions on the interior side walls for receiving the folded sections 82 of the liner bag 24 to achieve the interlocking effect. For example, container 84 may be manufactured from injection moulded plastic, and provided with the indented portions suitably shaped to receive the folded sections of the liner bag.

Although the above method and system of packaging has been described with reference to the storage of fresh or frozen food produce, it will be obvious that the system and method is also applicable for packaging other goods that are sensitive to variations in temperature and/or humidity. For example, the method and system of packaging according to the invention can also be applied to the storage of photographic materials and films, chemicals, and sensitive electronic apparatus and instruments.

Now that preferred embodiments of the system and method of packaging, including the liner bag and the relatively rigid container, have been described in detail it will be apparent that numerous variations and modifications can be made, other than those already described, without departing from the basic concepts of the invention. For example, it is to be understood that the composite material used for lining the container or for constructing the liner bag is not limited to the particular combination of materials described and may be, for example, a simple laminate of metallized polythene with open-celled plastic insulating material bonded thereto. Furthermore, the moisture impervious inner skin of liner bag 24 may be a webbed or woven plastic material to increase the strength of the liner bag and to make it puncture proof for containing sharp objects. All such variations and modifications are to be considered within the scope of the invention, the nature of which is to be determined from the foregoing description and the appended claims.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A packaging system for packaging goods that are sensitive to variations in temperature, the system comprising: a relatively rigid container for containing said goods ; and a flexible liner constructed of composite material including a reflective skin and a thermal insulating material bonded thereto whereby, in use, the flexible liner enhances the thermal insulating properties of the container so that goods held therein can be protected more effectively from variations in temperature.

2. A packaging system as claimed in Claim 1, wherein the composite material further comprises a moisture impervious skin, said composite material having the thermal insulating material provided between the reflective skin and the moisture impervious skin.

3. A packaging system as claimed in Claim 2, wherein said flexible liner is in the form of a bag adapted to be received within said container and wherein said reflective skin forms the outermost wall of the bag and said moisture impervious skin forms the innermost wall of the bag.

4. A packaging system as claimed in Claim 3, wherein said flexible liner bag is provided with a skirt of flexible material extending from the mouth of the bag whereby, in use, the bag can be hermetically sealed by the application of heat and/or pressure to said skirt.

5. A packaging system as claimed in Claim 1, wherein said container is constructed from a fluted material to provide an air barrier for additional thermal insulation.

6. A packaging system as claimed in Claim 3, wherein said flexible liner bag is provided with crease marks therein adjacent a bottom portion of the bag whereby the crease marks enable said bottom portion to form a substantially flat base section, adapted to fit in the base of said container, and to form two folded sections adapted to interlock with said container whereby, in use, said liner bag can be more securely retained in said container by the interaction of said folded sections with the container.

7. A packaging system as claimed in Claim 6, wherein said container is provided with indented portions on an interior surface thereof for receiving said folded sections of the liner bag whereby, in use, the liner bag and the container interlock.

8. A packaging system as claimed in Claim 7, wherein said container is constructed of a single semi-rigid sheet of planar material folded to form a rectangular box wherein first and second opposed side walls of the box are formed by folding said planar material in such a manner that the folds form an inverted V-shaped intrusion on an interior surface of both said side walls, said inverted V-shaped intrusions providing said indented portions for receiving the folded sections of the liner bag.

9. A packaging system as claimed in Claim 1, wherein said flexible liner is bonded to an inner surface of the container with said thermal insulating material located between the container inner surface and said reflective skin.

10. A packaging system as claimed in Claim 9, further comprising a moisture impermeable liner bag received in the container, said liner bag being hermetically sealable to further protect the contents of the container from variations in humidity.

11. A flexible liner bag for use in a packaging system for packaging goods that are sensitive to variations in temperature, the liner bag being constructed from a composite material including a reflective outer skin and a thermal insulating material bonded thereto, and being adapted for lining a relative rigid container to enhance the thermal insulating properties of said container, said liner bag being provided with crease marks therein adjacent a bottom portion of the bag whereby said crease marks enable said bottom portion to be readily folded to form a substantially flat base section, adapted to fit in the base of said container, and to form two folded sections adapted to interlock with said container whereby, in use, said liner bag can be more securely retained in said container by the interaction of said folded sections with said container.

12. A flexible liner bag as claimed in Claim 11, wherein said liner bag is constructed from a rectangular sheet of said composite material, arranged to form a bag that lies flat in its unfolded condition, and wherein said crease marks comprise first and second crease marks extending substantially perpendicularly to a side edge and said bottom edge of the bag respectively at both bottom corners of the bag, the length of said crease marks determining the width of said base section of the bag in its folded condition.

13. A flexible liner bag as claimed in Claim 12, wherein said crease marks are formed by the application of heat and/or pressure to the composite material.

14. A flexible liner bag as claimed in Claim 11, further comprising a valve system provided in a wall of the bag for preventing atmospheric gases from entering the bag whereby, in use, atmospheric gases trapped in the bag after sealing can be evacuated to aid in preserving the contents.

15. A flexible liner bag as claimed in Claim 14, wherein said valve system comprises a one-way valve means having a body provided with an orifice and a closure element for closing said orifice wherein said orifice enables gases to communicate from the interior of the bag to the exterior of the bag and said closure element is movable to an open position to allow gases to pass through to the exterior of the bag and to a closed position to prevent gases from passing through the orifice to the interior of the bag.

16. A flexible liner bag as claimed in Claim 15, wherein said closure element is normally resiliently biased to the closed position.

17. A flexible liner bag as claimed in any one of Claims 11 to 16, further comprising a skirt of flexible material extending from the mouth of the bag whereby, in use, the bag can be hermetically sealed by the application of heat and/or pressure to said skirt.

18. A method of packaging goods that are sensitive to variations in temperature, the method comprising: lining a relatively rigid container with a flexible liner wherein said liner is constructed of composite material including a reflective skin and a . thermal insulating material bonded thereto; placing said goods within the lined container; and closing the container whereby, in use, said flexible liner enhances the thermal insulating properties of the container so that goods held therein can be protected more effectively from variations in temperature.

19. A method of packaging goods as claimed in Claim 18, wherein said composite material further comprises a moisture impervious skin, the composite material having the thermal insulating material provided between the reflective skin and the moisture impervious skin.

20. A method of packaging goods as claimed in Claim 19, wherein said flexible liner is in the form of a liner bag and the method further comprising the step of sealing the liner bag to ensure controlled humidity and/or temperature conditions within the bag.