WO1990001005A1

WO1990001005A1 - Food packaging with gases between tensioned film, lid and food

Info

Publication number: WO1990001005A1
Application number: PCT/AU1989/000308
Authority: WO
Inventors: Anthony James Murray Garwood
Original assignee: Seawell Corp NV
Current assignee: Seawell Corp NV
Priority date: 1988-07-21
Filing date: 1989-07-21
Publication date: 1990-02-08
Anticipated expiration: 1991-01-21

Abstract

An improved packaging and method are disclosed. The packaging comprises a base (1), goods such as red meats (3) in the base (1), a lid (9) over the base (1), and a gas permeable web (7) stretched and bonded stretched to maintain stretching forces therein so that it is held to the base (1) above the red meats (3). A first space S1 is provided above the web (7) and under the lid (9). A second space S2 is provided under the web (7) and the base (1). The height of the red meats (3) is below the web (7) so the web (7) does not touch the top of the red meats (3). A desired gas such as 80 % O2 and 20 % CO2 can be provided in space S1 whilst a further desired gas can be provided in space S2. There will be an interchange of gases through the gas permeable web (7) which will act with the red meat (3) to enhance its keeping properties.

Description

FOOD PACKAGING VTffl GASES BETWEEN TENSIONED FILM, LID AND FOOD

Field of the Invention

This invention relates to an improvement of the invention disclosed in our International Application No. PCT/AU87/00297 and particularly but not exclusively to improved packaging where the goods therein such as fresh meats and/or other like perishable goods are covered with a web of plastics material and wherein the packaging contains a gas to enhance the keeping properties of the goods packaged therein. The subject matter of Application No. PCT/AU87/00297 is incorporated herein by this reference. Description of the Prior Art Skin wrapping/packaging is a technique where goods such as meat can be packaged and where substantially all of the air and/or gases which surround the meat or other goods is evacuated.

Figures 1 and 2 show a form of plastics material packaging which has been proposed hitherto and which is generally disclosed in PCT Patent Application PCT/AU86/00339 in the name A.J.M. Garwood and Garwood Limited. The subject matter of PCT/AU86/00339 is incorporated herein by reference. In this packaging there is provided a plastics material base 1 with goods 3 such as fresh meat, fish, poultry and/or vegetables packaged therein. The base 1 has a peripheral lip 5 and the upper surface of the goods 3 is shown lower than the lip 5. A skin wrapping plastics material 7 is fitted over the goods 3 and is bonded to the peripheral lip 5 as by welding or the like bonding techniques. The skin wrapping 7 extends downwardly from the lip 5 and closely surrounds the upper surface of the goods 3 so that substantially all air and/or gases are excluded from the space between the base 1 and the skin 7. A plastics material lid 9 is provided over the skin 7 and is bonded to the base 1 around the peripheral lip 5. A space 11 is provided between the lid 9 and the skin 7. The space 11 can contain a gas which will assist the keeping of the packaged goods 3. In this connection the gas can be either, or a combination of gas such as 0_, N-, C0₂ which can enhance the colour and keeping qualities of the packaged goods 3 such as red meats.

The plastics material for the base 1, the skin 7 can be clear plastics materials. Typically the base 1 is PVC, the skin 7 is a co-extruded plastic such as PE/EVA and the lid 9 is a plastics material such as PVC/PE. The base 1, the skin 7 and/or the lid 9 may be multi-layered webs where selective plastics materials are employed to enable suitable bonding as by heat bonding caused by, for example, a heat bank or by RF welding, and to enable selective exclusion and/or transmission of gases through the various webs and particularly skin web 7. Statement of the Invention The present invention attempts to provide an improved packaging.

Therefore, according to a first broad aspect of the present invention there may be provided a plastics material packaging for meat or other like goods comprising, a base of plastics material, a plastics material web overlaying the meat or other like goods on said base, and a lid of plastics material fitted over said plastics material web and bonded relative to said base around the periphery of said base, there being a first space between said lid and said plastics material web, a desired gas in said first space, said skin being permeable to allow said gas in to permeate therethrough to enhance the keeping qualities of said goods, said packaging having said plastics material web held bonded, in tension, overlaying but not touching said meat or other like goods. In accordance with a further broad aspect of the present invention there may be provided a method for producing a packaging of the above type comprising, providing a plastics material base, providing meat or other like goods on said base, providing a plastics material gas permeable web over said meat or other like goods, bonding said web to said base around the periphery of said base, placing a lid of plastics material over said web and bonding it whilst under tension relative to said base so after bonding tension will remain in said web, there being a first space between said lid and said skin, providing a desired gas in said first space so that said gas can permeate into the other of the spaces, said web being held bonded, in tension, overlaying but not touching said meat or other like goods.

Preferably the desired gas is about 80% oxygen and about 20% carbon dioxide for red meats. If desired there can be a desired gas under said web and this may comprise substantially 100% carbon dioxide. However, other gases to enhance the keeping properties of the packaged goods could be used if desired.

When there is a desired gas in the first space and a desired gas under the web, there can be an interchange of gases through the web whereby the goods keeping properties can be enhanced by the goods being in a desired gas environment.

Brief Description of the Drawings In order that the invention can be more clearly ascertained reference will now be made to the accompanying drawings wherein:

Figure 1 is a top perspective view of one known plastics material packaging;

Figure 2 is a cross-sectional view taken vertically through the packaging shown in Figure 1;

Figure 3 is a view similar to that of Figure 2 but showing an example of one preferred embodiment of improved packaging according to the present invention;

Figure 4 is a detailed close up view of a side edge of the base according to an embodiment of the invention; and Figure 5 is a detailed close up view, similar to that of Figure 4, showing how the web can be stretched prior to bonding.

Description of Preferred Embodiments Referring now to Figure 3, there is shown a packaging which will have the same designations as the packaging shown in Figures 1 and 2. In the embodiment shown in Figure 3 the base 1 has a second lip 13 which is displaced downwardly closer to the bottom 15 of the base 1 than the lip 5. Preferably the second lip 13 is parallel with lip 5. The web 7 is bonded to the second lip 13 as shown by numeral 17. The bonding is preferably by a_. heat bonding which can be performed by using a heat bank type bonding member. The lid 9 is bonded completely around the perimeter of the base 5 by bonding at the region 19. This bonding also is to the web 7 which overlays the lip 5. The web 7 is stretched so that it is under tension prior to bonding so that after bonding it is under tension and held taught across the bonding but not touching the upper surface of the goods 3. Typically the base 1 is of PVC/PE, the web 7 of a

LLDPE material and the lid 9 is of PVC/PE. The base 1 can be 200-600 microns thick. The web 7 can be 10-100 microns thick and the lid 9 50-150 microns thick. The web 7 may extend across the package, as shown in Figure 3, above the goods 3 without contacting the goods 3. The web 7 is gas permeable and divides the packaging into a first space Si between the lid 9 and the web 7 and a second space S2 between the web 7 and the bottom 15 of the base 1. A first gas is provided in the space Si and a second gas is provided in the space S2. The first gas may be about 20% carbon dioxide and about 80% oxygen for red meats, and the second gas may be substantially 100% carbon dioxide or it may comprise atmospheric air although this is not preferable owing to the anticipated short life of packaged goods such as red meat in such a gas environment. In other embodiments the gas in the space Si could for example be 100% oxygen, and the gas in the space S2 could for example be 50% carbon dioxide and 50% nitrogen. Other gases could be suitably chosen for their keeping qualities of the packaged goods. The chosen gases enhance the keeping qualities of the packaged goods and, the keeping qualities are further enhanced^' by the provision of the two different types of gases and the interchange of gases provided by gas permeable web 7. In the case of packaged red meats, during the life-time of the package, oxygen contained in the space Si is able to permeate through the web 7 into the space S2 which maintains the colouring of the meat 3 contained in the space S2. Carbon dioxide in the space S2 permeates through the web 7 into the space SI. This interchange of gas can take place over the storage life of the package to thereby change the environment in which the goods 3 are packaged to thereby enhance the keeping qualities of the packaged goods and maintain the colour of the goods. The amount of gas which is exchanged through the web 7 and the amount of time which passes prior to gas exchange can be determined by suitable selection of the permeability of the web 7. The permeability of the web 7 can be selected by choosing a suitable gauge for the web 7 or in any other suitable manner. Preferably for red meat packaging, the permeability is chosen so that oxygen does not pass through the web 7 for a number of days and thereafter begins to pass through the web 7 so as to assist in maintaining the colouring of the meat after that time period has expired.

Since carbon dioxide in the space S2 also permeates through the web 7, the gas pressure in the space S2 may decrease. The decrease in pressure of the carbon dioxide in the space S2 may also occur due to the carbon dioxide dissolving due to contact with the surface of the goods 3 or any other moisture in the space S2. The reduction in pressure in the space S2, of course, creates a partial vacuum in the space S2 which tends to draw the web 7 downwardly towards the goods 3. The tension in the web 7 may change slightly after a period of time, but the relationship is such that there will be a substantially, continuously applied tension in the web 7. The tension forces, in effect stretch the web 7 so that it appears like a double glazed window, when viewed through the lid 9. Referring now to Figure 4 there is shown a close-up detail of the lip region of the packing shown in Figure 3. It can be seen that lip 5 is generally horizontally extending and parallel with the bottom 15 of the base 1. The upper side wall 27 between lip 13 and lip 5 is generally vertical. Similarly the lower side wall 28 below the lip 13 is generally vertical. In one particular embodiment, it is proposed that the depth of the packaging below lip 13 be changeable at the time of making the base 1 to compensate for different thicknesses of goods 3 which are to be packaged within the packaging. Accordingly, depth 29 can be varied and depth 31 also can be arranged to be variable. The requirement is to provide a base 1 where the upper surface of the goods 3 will be below the stretched web 7.

Figure 5 shows one example of how the web 7 can be • stretched prior to bonding. Here, the web 7 is held around the peripheral lip 5 by a die part (not shown) and wherein a platen 33 with downwardly extending flexible fingers or webs 35 is pushed downwardly into space Si, thus stretching the web 7, whereupon it can be bonded to the lip 13. The webs 35 have rounded forward ends 37 to assist movement of the web 7 into the desired position without tearing of the web 7. Heat bonding or other bonding can be effected by a bonding member which can pass between the web 35 and the side walls 27 to permit bonding to lip 13. By not skin wrapping the web 7, as in the disclosure in the aforementioned PCT specification PCT/AU87/00297 and PCT/AU86/00339, a satisfactory packaging is still obtained. We have found that the keeping properties of the packaged goods such as red meats are comparable to those in accordance with the aforementioned PCT patent specification. Moreover the packaging is still aesthetically acceptable as the double glazing effect caused by the lid 9 and web 7 provides a pleasing quality to the packaging. In addition it is possible for some markets to produce a less expensive packaging machine because it is no longer necessary to have to evacuate or create a lower gas pressure differential under web 7 to effect skin wrapping.

Since modification within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiments described by way of example hereinabove.

Claims

CLAIMS:

1. A plastics material packaging for meat or other like goods comprising, a base of plastics material, a plastics material web overlaying the meat or other like perishable goods on said base, and a lid of plastics material fitted over said plastics material web and bonded relative to said base around the periphery of said base, there being a first space between said lid and said plastics material web, a desired gas in said first space, said skin being permeable to allow said gas in to permeate therethrough to enhance the keeping qualities of said goods, said packaging having said plastics material web held bonded, in tension, overlaying but not touching said meat or other like goods which is in a second space between said lid and said base.

2. Packaging as claimed in Claim 1 wherein said base is between 200-600 microns thick, said lid between 50.-150 microns thick, and said web is between 10-100 microns thick.

3. Packaging as claimed in Claim 2 wherein said base is a multi-web of PVC/PE, said lid is a multi-web of PVC/PE, and said web is of LLDPE.

4. Packaging as claimed in Claim 1 wherein there are different gases in said first space and said second space, each selected for enhancing the keeping properties of the meat or other like perishable goods by an interchange of gases through said web.

5. Packaging as claimed in Claim 1 wherein said base has a peripheral lip below the top of said base and the bottom of said base, said peripheral lip being above the top of the meat or other like perishable goods, and wherein said web is stretched across the goods and bonded to said lip so it is maintained stretched.

6. Packaging as claimed in Claim 1 wherein the gas in said first space comprises approximately 80% 0_ and approximately 20% CO-, for red meats.

7. Packaging as claimed in Claim 1 wherein the gas in said first space comprises approximately 100% 0₂, and the gas in said second space comprises approximately 50% CO- and approximately 50% N_.

8. A method for producing a packaging of the above type comprising, providing a plastics material base, providing meat or other like goods on said base, providing a plastics material gas permeable web over said meat or other like goods, bonding said web to said base around the periphery of said base, placing a lid of plastics material over said web and bonding it whilst under tension relative to said base so after bonding tension will remain in said web, there being a first space between said lid and said skin, providing a desired gas in said first space so that said gas can permeate into the other of the spaces, said web being held bonded, in tension, overlaying but not touching said meat or other like goods which is in a second space between said lid and said base.

9. A method as claimed in Claim 8 comprising providing said base with a peripheral lip below the top of said base and above the bottom of said base, placing meat or other like perishable goods in said base so the upper surface of said goods is below said peripheral lip, stretching said web over said meat or other like perishable goods in said base and bonding said web.to peripheral lip to maintain it stretched.

10. A method as claimed in Claim 9 comprising providing a further desired gas in said second space.

11. A method as claimed in Claim 8 wherein said gas is provided to be approximately 80% 0- and approximately 20% C0₂ for red meats.