GB2504993A

GB2504993A - A hydrogen generating and oxygen absorbing device for food packaging

Info

Publication number: GB2504993A
Application number: GB201214684A
Authority: GB
Inventors: Nigel Parker; John Hirst
Original assignee: EMCO PACKAGING SYSTEMS Ltd
Current assignee: EMCO PACKAGING SYSTEMS Ltd
Priority date: 2012-08-17
Filing date: 2012-08-17
Publication date: 2014-02-19
Also published as: GB201214684D0

Abstract

A hydrogen generating and palladium catalysed, oxygen absorbing device for food packaging inclusion comprises a first chamber and a second chamber defined by laminar layers C, E that are impermeable to water in the liquid phase but permeable to water vapour and gases. The first chamber contains a fill formulation D, which when activated by water vapour, generates hydrogen, preferably the formulation is a metal hydride. The second chamber contains a substrate carrying a deposit of finely divided palladium F for catalysing reaction between the generated hydrogen and atmospheric oxygen from the container. The laminar layers C, E are preferably a bi-laminar layer formed from a polymer membrane such as polyethylene terephthalate or polyamide supported on high density polyethylene. The device may be provided in the form of a disc, self adhesive label or sachet to allow the establishment and maintenance of an oxygen free atmosphere within the headspace of bottles, cans, sachets or cartons of aqueous liquid foods and beverages.

Description

AN ACTIVE, PALLADIUM BASED, OXYGEN SCAVENGING, PACKAGING INCLUSION SYSTEM, DESIGNED TO OPERATE IN THE PRESENCE OF FREE

WATER

Introduction to the invention

Field of the Invention

This invention relates to a hydrogen based, palladium catalysed, oxygen absorbing food packaging inclusion, in the form of a water impermeable but water vapour and gas permeable, dual chambered device, containing respectively water vapour activated, hydrogen generating compounds and the palladium catalyst.

This device has been designed as an active inclusion for deployment, in the presence of free, aqueous liquids, within the caps or closures of retail and wholesale packaged liquid foods and beverages, in order to establish and maintain a stable, oxygen free atmosphere within the headspace of the packaging concerned.

Description of the Related Art

In the case of beverages, such as beers and wines, soft drinks, fruit juices and some dairy based drinks, the presence of oxygen, even at very low levels, within the packaging, whether bottles, cans or cartons, can have a significant adverse affect on the quality of the product, to the point where it is no longer acceptable at retail.

The presence of oxygen can be reduced firstly by purging with nitrogen any dissolved oxygen in the product concerned and then employing, at packing, a nitrogen back-flush to ensure the minimum level of oxygen within the head space.

This process, however, can not displace all of the oxygen and with containers other than glass, there is also the potential continuous migration of oxygen, by diffusion down a concentration gradient from the surrounding ambient atmosphere, through the packaging, both into the head space and into the product itself.

The deployment of oxygen absorber, or scavenger' packaging inclusions currently in the market place, would be effective in removing, very largely, the oxygen within the head space atmosphere and as a consequence, that dissolved in the product itself and thereafter in maintaining oxygen at very low, residual levels.

The above inclusions, however, are unable to be deployed in the presence of free aqueous liquids as their structure, in terms of the outer envelope, which retains the active oxygen absorbing fill material, is porous to liquid water.

The inundation in aqueous liquids, whether it be partial or temporary, of the active oxygen absorbing fill materials in question, will either severely reduce their efficacy or render them entirely ineffective.

Apart from the performance efficiency of the active oxygen absorbing fill materials under these conditions, there is also the issue of the leached migration of the chemical components of these materials into the product itself, especially under low pH conditions, which many of the aqueous liquid foods and beverages concerned provide.

Under these conditions, of those oxygen scavengers currently available commercially and designed for deployment within food products, the range of fill material formulations represented all present difficulties in meeting the permitted maximum migration levels as detailed in EC Directive 97/481EC, as required by current and forthcoming EU legislation and EFSA regulations.

Summary of Invention

According to the invention there is provided a device according to claim 1.

In another aspect, there is provided a method according to claim 17.

The device in this invention, is based on a palladium catalysed reaction between molecular hydrogen and molecular oxygen, effectively removing the latter gas from the headspace, as a component of the reaction product, water vapour.

The device in this invention has been designed with an integrated water vapour activated hydrogen generation source and palladium catalyst.

The invention also relates to a food package in which the device is incorporated in a cap or closure.

Detailed Description

The device in this invention, in an embodiment, is shown in Fig 1., where A is a disc of a non-woven wadding fabric based on polypropylene (PP), polyester and cellulose with an acrylate-based binding aid, or a material combination of similar properties and performance..

The wadding fabric is faced with an adhesive bonded, polymer film layer (B), as an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase, which can be polyethylene terephthalate (PET), a polyamide (PA)/polyethylene (PE) 40160 co-extrusion or a PAIPP 40/75 co-extrusion.

A piano-concave formed layer (C) is circumference bonded to the above facing material, which provides an inner envelope to contain, within the chamber created, the water vapour activated, hydrogen generating fill material (D).

The water vapour activated, hydrogen generating fill material formulation may comprise a metal or a metal hydride or a metal borohydride or a combination of two or more.

If selected, the said metal may be potassium, magnesium, zinc or aluminium.

If selected, the said metal hydride may be sodium hydride, magnesium hydride, or calcium hydride.

If selected, the said metal borohydride may be sodium borohydride or lithium borohydride.

As both the reactivity of most of the above metals and metal hydrides and the potential toxicity of the borohydrides could present technical, although not insurmountable difficulties in the manufacture of the device, the preferred hydrogen generating compounds are magnesium hydride and calcium hydride.

In order to control the rate of reaction in the presence of water vapour, the magnesium hydride or calcium hydride will be combined, in the fill material formulation, with a Bentonite having a moisture content of less than 2.0%, which being considerably more hygroscopic than the hydrides, will more successfully compete for the water vapour available, thus regulating the rate of the hydrolysis reaction of the hydrides.

The mass of the selected hydride or hydrides within the fill material formulation will be determined by the shelf life required and the consequent total demand for oxygen removal from the headspace imposed by the overall OTR of the beverage packaging and may vary from product to product.

The rate of hydrogen generation is designed to be greater than the rate of inward movement of oxygen into the headspace by a factor of at least 2 (see reaction equation, paragraph 83 below).

The respective percentage composition of the selected hydride, or hydrides and the reaction regulating Bentonite within the fill material formulation will also be determined by the shelf life required and the consequent demand for oxygen removal from the headspace imposed by the overall OTR of the beverage packaging and may vary from product to product.

The hydrogen generating fill material requires contact with water vapour to both initiate and maintain the reaction, which in turn requires that water vapour is allowed a controlled rate of diffusion into the inner envelope from the headspace of the packaged beverage concerned.

In order to meet this requirement and allow the fill material to perform optimally, the inner envelope of the device is designed to have a water vapour transmission rate (WVTR) and an oxygen transmission rate (OTR) that are both high enough to avoid becoming limiting factors.

This is achieved by employing an outer polymer membrane with both a relatively high WVTR and OTR, as the fully effective barrier to water in the liquid phase within the device inner envelope.

The polymer membrane selected, depending on the water vapour and gas transmission rate requirements imposed by the overall OTR of the beverage packaging, can be a polyamide as PA6 or a PA copolymer (coPA) film, with a thickness of 8pm -2Opm or a PET film, with a thickness of 10pm -2Opm or a PE film, with a thickness of 10pm -25pm. For the majority of applications, PA6 or coPA are the preferred polymers.

Within the piano-concave formed layer (C), as indicated above, the selection of the polymer membrane and its gauge of thickness is designed as the primary means of regulating water vapour availability to the fill material formulation and is imposed by the hydrogen generation demands created by the overall OTR of the beverage packaging and may vary from product to product.

At the above gauges selected, the polymer membrane is relatively fragile and in order to maintain its integrity and thus avoid perforation, it is protected and mechanically supported by an inner membrane of a spun-bonded, high density polyethylene (HDPE) fabric, typically at a density of 42.5 gIm2, which for preference would be Tyvek 1025B.

This material is not an effective barrier to liquid water, water vapour, oxygen or hydrogen.

The resulting bi-laminate material of the piano-concave formed layer (C) above, therefore comprises an inner mechanical support membrane of a gas and liquid permeable, spun-bonded, HDPE, 42.5g1m3 fabric, such as Tyvek 1025B, which is bonded to an outer, water vapour transmission regulating PA6 or coPA film, 8p -20p in thickness or a PE film, l5pm -25pm thickness or a PET film, 10pm -2Opm in thickness and overall is impermeable water in the liquid phase but with a WVTR in the range of lOg-200g/m2/24hr © 23°C & 85%RH and an OTR in the range of 100cm3- 20,000cm3/m2/24hr/bar © 23°C.

The inner, mechanical support membrane and the outer, water vapour transmission regulating polymer film comprising the laminate above, are bonded together with a 4g1m2, mono-component, polyurethane based, solvent-free adhesive, or a material of equivalent properties and performance, the composition and thickness of which will have a negligible effect on either the WVTR or OTR of the outer, water vapour transmission regulating PA6 or coPA film or the laminate in general.

An overlying, slightly deeper, piano-concave layer (E) is circumference bonded to the piano-concave formed layer (C) and provides an outer envelope to contain, within the chamber created, the palladium catalyst.

The palladium (Pd) catalyst can be in the form of: - finely comminuted palladium metal deposited, under a patented process, on to a non-woven, fibrous, polyacrylate polymer fabric, commercially known as Smoptech, finely comminuted palladium adsorbed on to zeolite and applied under a patented process as a thin coating to a polymer film finely comminuted palladium metal deposited, under a patented process, on to a non-woven, fibrous, polypropylene polymer fabric substrate, finely comminuted palladium metal deposited, under a patented process, on to porous aluminium oxide substrate The Pd particle size, in order to provide the required efficiency of reaction, ranges from O.lpm to O.5pm in diameter and is deposited on the selected substrate at a density of approximately 0.15mg/cm2.

The Pd, in the presence of hydrogen, acts as a catalyst, combining the former gas with oxygen, effectively removing the latter from the headspace, in the form of water vapour, as the reaction product.

The Pd catalyst requires contact with both molecular hydrogen and molecular oxygen to initiate and maintain the reaction, which in turn requires that the two gases are allowed to diffuse freely into the camber of the outer envelope from both the chamber of the inner envelope and the headspace of the packaged beverage concerned.

It is also required that as water vapour is the product of the catalysed reaction between hydrogen and oxygen, it is allowed to diffuse freely from within the chamber of the outer envelope of the device, into the both the chamber of the inner envelope and the headspace of the packaging concerned, in order to prevent any build-up of pressure or liquid water condensate within the outer envelope, resulting in rupture and consequent loss of integrity.

In order to meet these requirements and allow the Pd catalyst to perform optimally, the outer envelope of the device is designed to have a water vapour transmission rate (WVTR) and an oxygen transmission rate (DIR) that are both high enough to avoid becoming limiting factors in the oxygen absorbing performance of the above catalyst..

This is achieved by employing a polymer membrane with a relatively high WVTR and OTR as the fully effective barrier to water in the liquid phase within the device outer envelope.

The polymer membrane, selected for the piano-concave layer (E) of the outer envelope, is a PA6 or coPA film, 8pm -2Opm in thickness, which is liquid water impermeable and has a WVTR in the range of BOg-i 2OgIrn2I24hr @ 23°C & 85%RH and an OTR in the range of iOOcm3-600cm3Im2t24hrtbar @23°C.

The gauge of the PA6 or coPA film, within the range 8p -20p, selected for inclusion in the outer envelope is also determined by the WVTR and OTR required by the performance demands on the fill material within the inner envelope, imposed by the packed product in question and will vary from product to product.

At the above gauges selected, the polymer membrane is relatively fragile and in order to maintain its integrity and thus avoid perforation, it is protected and mechanically supported by an inner membrane of a spun-bonded, HDPE fabric, typically at a density of 42.5g1m2, which for preference would be Tyvek 1025B. This material is not an effective barrier to liquid water, water vapour, oxygen or hydrogen.

The resulting bi-laminate material of the piano-concave formed layer (F) above, is therefore comprised of an inner mechanical support membrane of a gas and liquid permeable, spun-bonded, HDPE, 42.5g1m3 fabric, such as Tyvek 1025B, which is bonded to an outer water vapour transmission regulating PA6 or coPA film, 8pm - 2Opm in thickness and overall is impermeable to water in the liquid phase but with a WVTR in the range of 80g-120g/m2124hr @ 23°C & 85%RH and an OTR in the range of lOOcm3-600cm3/m2/24hr/bar © 23°C.

The inner, mechanical support membrane and the outer, water vapour transmission regulating PA6 Or coPA film comprising the laminate above are bonded together with a 4g1m2, mono-component, polyurethane based, solvent-free adhesive, or a material of equivalent properties and performance,, the composition and thickness of which will have a negligible effect on either the WVTR or OTR of the outer, water vapour transmission regulating PA film or the laminate overall The bi-laminate material (E) of the outer envelope may be reverse printed, with suitable food contact approved inks, on the outer, water vapour transmission regulating, PA6 or coPA film, in order to meet the statutory requirements of prevailing food legislation.

The WVTR of the various, selected fabrics and films employed in the device may be measured by employing a commercially available water permeation analyser such as the MOCON PERMATRAN-W Model 3/33, which is designed to test this property of packaging films and has integral automatic relative humidity generation. The machine measures according to the ASTM standard F -1249.

The OTR of the various, selected fabrics and films employed in the device may be measured by employing a commercially available oxygen transmission rate analyser, such as the MOCON OX-TRAN Model 1/50, which is designed to test this property of packaging films. The machine measures according to the ASTM standard F-1927.

The manufacture of the device, for deployment as an inclusion insert within caps and closures of aqueous liquid food or beverage packaging, employs existing technology in the form of a modified, multi-station, thermoform and lamination process, in which the several components, in web form, are bought together and bonded to produce a complex laminate.

In the first stage of the manufacturing process the layer forming the inner envelope (C) is thermoformed into an indexed array of piano-convex, circular cavities of a standard diameter and depth and then also wound on to a core as a temporary holding stage.

In the second stage of the manufacturing process the layer forming the outer envelope (E) is also thermoformed into an indexed array of piano-convex, circular cavities of a predetermined, standard diameter and depth, which in this case is slightly deeper than that formed in the outer envelope material (C) and then again wound on to a core as a temporary holding stage.

In the third stage of the manufacturing process, the wadding fabric (A), based on non-woven PP, polyester and cellulose with an acrylate-based binding aid, or a material combination of similar properties and performance, which is over-layered with polymer film layer (B), which can be PET, at a thickness of 3Opm, a PA/PE 40/60 co-extrusion, at a thickness of 3Opm or a PA/PP 40/75 co-extrusion, at a thickness of 3Opm, employing a polyurethane adhesive, or a material of equivalent properties and performance and then wound on to a core as a temporary holding stage.

In the fourth stage of the manufacturing process the components produced during the first three stages are brought together horizontally, as indexed, overlying webs.

The lowest of the three webs produced is the now thermoformed layer of the outer envelope (E), in which the cavities are each index pre-charged with an identical, small section of the Pd loaded carrier material.

The middle of the three webs produced is the now thermoformed layer of the inner envelope (C), in which the cavities are each index pre-charged with an identical weight of the hydrogen generating fill material.

The upper of the three webs produced is the wadding fabric (A), over-layered with a selected polymer film facing.

The three webs are brought together, with the cavities of the outer envelope (E) accurately aligned with those of the inner envelope layer (C).and then bonded together around the circumference of the of the cavities by one of the alternatives of heat bonding, ultrasonic welding or dielectric welding.

The composite laminate material thus produced is then die-cut around the outer margin of the circumference welds to produce the individual caps and closures inserts.

The overall dimensions of the cavities produced in the piano-concave thermoforming of the inner and outer envelope layers ((C) and (D) respectively).reflect the sizes of the caps and closures of the beverage packaging concerned.

In another embodiment of this invention, the device may be in the form of a self adhesive label, as shown in Figure 2.

The manufacture of the device in the above embodiment, for deployment as an adhesive inclusion within aqueous liquid food or beverage packaging, also employs existing technology in the form of a modified, multi-station, thermoform and lamination process, in which the several components, in web form, are bought together and bonded to produce a complex laminate.

In the first stage of the manufacturing process of the above device, the wadding fabric (A) and polymer film layer (B) laminate, is replaced by a self-adhesive coated polymer film layer (H), which is an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase, which can be PET, PA6 or coPA/PE 40/60 co-extrusion or a PA/PP 40/75 co-extrusion and is overlaid by a low-tack, adhesive protecting, peelable, non-woven, cellulose based fabric (G).

The remaining components of the above device are as follows: -an inner envelope of a piano-concave formed layer (I) comprised of bi-larninate material with an inner mechanical support membrane of a gas and liquid permeable, spun-bonded, HDPE, 42.5g1m3 fabric, such as Tyvek 1025D, which is bonded to an outer, water vapour transmission regulating PA film, 8p -20p in thickness or PE film, l5pm -25pm thickness or PET film, 10pm -2Opm in thickness and overall is impermeable water in the liquid phase but with a WVTR in the range of lOg- 200g/m2/24hr © 23°C & 85%RH and an OTR in the range of 100cm3- 20,000cm3/m2/24hr/ bar © 23°C.

a water vapour activated, hydrogen generating fill material formulation (J) deposited within the cavities provided by the piano-concave formed inner envelope (I).

an outer envelope of a piano-concave formed layer (K) comprised of bi-laminate material with an inner mechanical support membrane of a gas and liquid permeable, spun-bonded HDPE, 42.SgIm3 fabric, such as Tyvek 1025B, which is bonded to an outer, water vapour transmission regulating PA6 or coPA film, 8p -20p in thickness and overall is impermeable water in the liquid phase but with a WVTR in the range of 80g-120g1m2124hr © 23°C & 85%RH and an OTR in the range of 100cm3- 600cm3/m2/24hr/bar @ 23°C.

a finely divided palladium (Pd) catalyst on a carrier substrate (L) deposited within the cavities provided by the piano-concave formed outer envelope (K).

In the above embodiment format, the device can be readily manufactured in a range of sizes In the above embodiment format, the device is intended to be placed and secured, in a pre-determined position, on the inner surface of the primary packaging of the packed food product.

In a further embodiment of this invention, the device may be in the form of a sachet, as shown in Figure 3.

The manufacture of the device in the above embodiment, for deployment as an inclusion within aqueous liquid food or beverage packaging, also employs existing technology in the form of a modified, multi-station, thermoform and lamination process, in which the several components, in web form, are bought together and bonded to produce a complex laminate.

The components of the above device are as follows: -an upper envelope of a piano-convex formed layer (M) comprised of bi-laminate material with an inner mechanical support membrane of a gas and liquid permeable, nonwoven HDPE, 40g/m3 fabric, such as Tyvek 1025B, which is bonded to an outer, water vapour transmission regulating PA film, 8p -20p in thickness and overall is impermeable water in the liquid phase but with a WVTR in the range of 80g- 120g1m2124hr @ 23°C & 85%RH and an OTR in the range of 100cm3- 600cm3/m2/24hr/bar © 23°C, a finely divided Pd catalyst on a carrier substrate (0) deposited within the cavities provided by the piano-convex formed upper envelope (M), a longitudinal septum, separating the upper and lower envelopes, comprised of a bi-laminate material with an inner mechanical support membrane of a gas and liquid permeable, spun=bonded, HDPE, 45.2g/m3 fabric, such as Tyvek 1035B, which is bonded to an outer, water vapour transmission regulating PA film, 8p -20p in thickness or PE film, l5pm -25pm thickness or PET film, 10pm -2Opm in thickness and overall is impermeable water in the liquid phase but with a WVTR in the range of lOg-200g/m2/24hr © 23°C & 85%RH and an OTR in the range of 100cm3- 20,000cm3Im2I24hr/bar © 23°C, a lower envelope of a piano-concave formed layer (P) comprised of a polymer film, which may be PET, at a thickness of 3Opm, a PA/PE 40/60 co-extrusion, at a thickness of 3Opm or a PA/PP 40/75 co-extrusion, at a thickness of 3Opm, impermeable water in the liquid phase and with a WVTR in the range of 3g-4g/m2124hr © 23°C & 85%RH and an OTR in the range of 50cm3-80cm3/m2124hr/bar © 23°C.

a water vapour activated, hydrogen generating fill material formulation (0) deposited within the cavities provided by the piano-concave formed lower envelope (P).

In the above embodiment format, the device can be readily manufactured in a range of sizes In the above embodiment format, the device is intended to be placed loose within the primary packaging of the packed food product concerned.

In either of the latter two embodiment formats, the dimensions of the device and thus its surface area will reflect both the mass and formulation volume of the fill material required to effect the oxygen scavenging, pack atmosphere control desired, although it is, nevertheless, intended that it will form a relatively discrete an unobtrusive food packaging inclusion.

At manufacture, the device in this invention, in all its embodiments, in order to prevent premature activation by water vapour in the ambient atmosphere, will require to be vacuum packed within effective high barrier to water vapour transmission packaging and remain so until the point of deployment.

In the case of caps and closures insert inclusions, these can be fitted to the respective cap or closure in a controlled, very low humidity environment, with a restricted exposure time and then vacuum packed within effective, high barrier to water vapour transmission packaging, together with an appropriate desiccant pack and remain so until the point of deployment.

In deployment, the caps and closure with the pre-fitted insert inclusion, the self-adhesive labels and sachet will be removed from their atmospheric moisture packaging only immediately before introduction to the beverage packaging and the filling and sealing of the latter.

In operation, once deployed, the device is activated by water vapour from the headspace, first diffusing through the bi-laminate material of the outer (or upper [Figure 3])) envelope, as shown in Figure 1., into the chamber containing the Pd catalyst, then diffusing though the bi-laminate envelope material of the inner (or lower [Figure 3.]) envelope (E).

On reaching the chamber of the inner envelope, the water vapour will initiate an hydrolysis reaction with the selected metal, hydride or borohydride within the fill material formulation, one of the reaction product of which will be molecular hydrogen.

The rate of the hydrolysis reaction will be regulated both by the rate of diffusion of water vapour through the bi-laminate material of the inner envelope and the level of competitive absorption of water vapour by the Bentonite component of the fill material formulation.

An initial stage of regulation is also provided by the bi-laminate material of the outer envelope (E), with the rate of diffusion of water vapour into the device controlled by the gauge selection of the PA6 a coPA film outer layer of the bi-laminate material.

As hydrogen has comparatively a very small molecule, the transmission rate of this gas through the PA6 or coPA film, will be significantly greater than that of oxygen through this polymers, exceeding the latter rate by a factor greater than 2, thus adequately meeting the minimum requirements to provide 2 molecules of hydrogen for 1 of oxygen in the Pd catalyzed reaction..

The reaction equations for the production of hydrogen from a metal, an hydride and a borohydride respectively are shown below: -Metal: 2A1 + 31120 -. 3112 + A1203 Aluminium Water Hydrogen Aluminium triodde Hydride: MgH2 + 2H20 2H2 + Mg(OH)2 Magnesium Water Hydrogen Magnesium hydride hydroxide Borohydride: LiBH4 + 2H20 -. 4H2 + LiBO2 Lithium Water Hydrogen Lithium borohydride metaborate The hydrogen gas produced by the above reactions will diffuse from the chamber of the inner envelope, through the envelope material and into the chamber of the outer envelope, where it will take part in a Pd catalysed reaction with the oxygen, which has diffused into the outer chamber from the headspace, as shown in Figure 1., with water as the reaction product.

The equation for the Pd catalysed reaction between molecular hydrogen and molecular oxygen is shown below: -Pd catalyst 2H2 + 02 2H20 Hydrogen Oxygen Water Water, as the reaction product, is produced as water vapour, which can diffuse out of the chamber of the outer envelope, into both the headspace and the chamber of the inner envelope.

In polymer based beverage packaging, the transmission rate of hydrogen through the packaging wall is 10 to 20 times greater than that of oxygen, which makes it important to control the rate of reaction of the hydrogen generating component of the fill material and the consequent volume of hydrogen evolved in order to avoid rates off loss that could reduce the operating life of the inclusion.

In a 330m1 PET beverage bottle with a headspace volume of 20m1 and having an inward transmission rate of O.035m1 02/day/container @ 23°C, a volume of less than O.7m1 of hydrogen within the headspace would produce an outward transmission rate greater than this.

Moreover the solubility of hydrogen in aqueous solutions is low and significantly lower than that of oxygen, which means that the concentration of hydrogen within the headspace will be relatively elevated in comparison to oxygen and in the same 330m1 PET beverage bottle as above, it would require a generation of only O.O7rnl -0.14m1 H2/day/container @ 23°C to react with the majority or all of the oxygen entering the bottle.

Taking the above example and employing magnesium hydride, the preferred hydrogen generating compound, the mass required to generate hydrogen, at the above rate, for a shelf life period of 180 days, would be in the range of 0.15g to 0.30g.

In non-polymer based beverage packaging, as for example aluminium cans, gas transmission rates are very low and restricted to the fold seams, the control of the rate of reaction of the hydrogen generating component of the fill material and the consequent volume of hydrogen evolved is now important in order to avoid the level of hydrogen within the headspace approaching the lower end of its flammabiflty Umits in air (SIP conditions) of 4.0 75.0 vol%.

Although the reaction between hydrogen and oxygen can be catalysed by a range of elements and compounds including transition metals, transition metal salts, metal carbides (e.g., titanium carbide), metal nitrites (e.g., titanium nitrite) and metal borides (e.g., nickel boride), the Group VIII metals, especially palladium, are preferred due to their low toxicity and efficiency in the redox catalysis of the above, with no reaction product formation other than that of water.

The mass of the palladium catalyst required is very small, with an approximate loading of 0.15 mg of Pd per cm2 of substrate and to maximize efficiency the particle size will be in the region of 0.lpm -0.5pm diam.

The device is comprised of a food packaging inclusion, in the form of dual chambered complex lamination, fabricated from several composite materials, being impermeable to water in the liquid phase but permeable to water vapour and gases and containing in one chamber a fill material formulation, which when activated by water vapour, generates hydrogen, while containing in the other chamber a substrate carrying a deposit of finely divided palladium, which will catalyse the reaction between the generated hydrogen and the oxygen from within the headspace, thus removing the latter gas and allowing the establishment and maintenance of an oxygen free atmosphere within the headspace of bottles, cans, sachets or cartons of aqueous liquid foods and beverages.

The device in the invention comprises a dual cambered, complex lamination, in which the two chambers are aligned horizontally, in parallel and immediately adjacent to one another The device in the invention comprises a dual chambered, complex lamination in which the inner chamber accommodates a fill material formulation designed to generate hydrogen in a reaction initiated by water vapour.

The above fill material formulation comprises a water vapour reacted, hydrogen generating metallic element or compound together with a competitive water vapour absorbing material such as Bentonite, or a material of equivalent properties and performance to control the rate of the above reaction.

The above fill material may comprise the following water vapour reacted, hydrogen generating metallic element, in powder format; -Alkali Metal (Group I) -Potassium (K) Alkali Earth Metal (Group II) -Magnesium (Mg) Transition Metal (Group XII) -Zinc (Zn) Post Transition Metal (Group XIII) -Aluminium.(Al) The above fill material may comprise the following water vapour reacted, hydrogen generating compounds, in powder format; -Hydrides -Sodium hydride (NaH), Magnesium hydride (MgH2), Calcium hydride (Ca H2), Borohydrides -Sodium borohydride (NaBH4), Lithium borohydride (LiBH4) The above fill material formulations, in terms of the selection of the hydrogen generating elements or compounds, together with their percentage composition with respect to the bentonite component, are designed to effect the pack atmosphere control required and are thus specific to the product packed and will therefore vary from product to product.

The above fill material formulations, in terms of the respective fill weights, are designed to deliver the overall output for the shelf life required and are thus specific to the product packed and will therefore vary from product to product.

In order to retain fully the fill material formulation selected, both dry and hydrated, when in contact with food and in the presence of water in its liquid phase, the envelope of the inner chamber is in two parts, with the upper face, as both an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase, which may be fabricated from PET, a PA6 or coPA/PE 40/60 co-extrusion or a PA6 or coPA/PP 40/75 co-extrusion.

The lower face of the envelope of the inner chamber also forms the upper face of the outer chamber is both permeable to water vapour and gases and a fully effective barrier to water in its liquid phase and is fabricated from a bi-laminate material, comprising an upper, permeable layer of a spun-bonded, opaque, 42.5g/m2 HDPE fabric, bonded with a 4g/m2 of mono-component, polyurethane based, solvent-free adhesive, to a water impermeable layer of a PA6 or coPA film, 8pm -2Opm in thickness, which is liquid water impermeable and has a WVTR in the range of 80g- 120g/m2/24hr © 23°C & 85%RH and an OTR in the range of 100cm3- 600cm3/m2/24hr/bar © 23°C.

The respective envelope materials of the inner chamber are designed to allow the transmission of water vapour and hydrogen at levels that enable the respective fill material formulations to perform optimally and are thus specific to the product packed and their detailed specification may therefore vary from product to product.

The gauge of PA6 or coPA film, deployed in the laminate of the lower face of the inner chamber envelope, is determined by the WVTR and OTR required by the performance demands of the fill material formulation imposed by the packed product in question and will vary from product to product.

The device in the invention comprises a dual chambered complex lamination, in which the outer chamber accommodates a rectangular section of a non-woven fabric or a porous metallic foil substrate carrying a deposit of finely divided Pd designed to catalyse the reaction between hydrogen and oxygen, with water being the reaction product.

The above Pd catalyst may be in the form of: - finely comminuted palladium metal deposited, under a patented process, on to a non-woven, fibrous, polyacrylate polymer fabric, commercially known as Smoptech, finely comminuted palladium adsorbed on to zeolite and applied under a patented process as a thin coating to a polymer film finely comminuted palladium metal deposited, under a patented process, on to a non-woven, fibrous, polypropylene polymer fabric substrate, finely comminuted palladium metal deposited, under a patented process, on to porous aluminium oxide substrate.

The particle size of the above Pd catalyst, in order to provide the required efficiency of reaction, ranges from O.lpm to 0.5pm in diameter and is deposited on the selected substrate at a density of approximately 0.15mg/cm2.

In order to retain fully the Pd catalyst and substrate, both dry and hydrated, when in contact with food and in the presence of water in its liquid phase, the envelope of the outer chamber is in two parts, with the upper face also forming the lower face of the inner chamber, as described above, providing an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase.

The lower face of the envelope of the outer chamber is both permeable to water vapour and gases and a fully effective barrier to water in its liquid phase and is fabricated from a bi-laminate material, comprising an upper, permeable layer of a spun-bonded, opaque, 42.5g1m2 HDPE fabric, bonded with a 4g/m2 of mono-component, polyurethane based, solvent-free adhesive, to a water impermeable layer of a PAO or coPA film, 8pm -1 5pm in thickness, which is liquid water impermeable and has a WVTR in the range of 80g-120g1m2124hr © 23°C & 85%RH and an QIR in the range of lOOcm3-600cm3Im2J24hrJbar © 23°C.

The respective envelope materials of the outer chamber are designed to allow the transmission of water vapour and hydrogen at levels that enable the respective fill material formulations to perform optimally and are thus specific to the product packed and their detailed specification may therefore vary from product to product.

The gauge of PA6 or coPA film, deployed in the laminate of the lower face of the envelope of the outer chamber, is determined by the WVTR and OTR required by the performance demands of the fill material formulation imposed by the packed product in question and will vary from product to product.

The device in its embodiment as a cap and closures inclusion insert is manufactured in a number of stages.

In the first stage of the manufacturing process the lower face of the envelope forming the inner chamber is thermoformed into an indexed array of piano-convex, circular cavities of a standard diameter and depth and then also wound on to a core as a temporary holding stage.

In the second stage of the manufacturing process the lower face of the envelope forming the outer chamber is also thermoformed into an indexed array of pIano-convex, circular cavities of a predetermined, standard diameter and depth, which in this case is slightly deeper than that formed in lower face the envelope forming the inner chamber and then again wound on to a core as a temporary holding stage.

In the third stage of the manufacturing process, the wadding fabric, based on non-woven PP polyester and cellulose with an acrylate-based binding aid, or a material combination of similar properties and performance, which is over-layered with polymer film layer (B), which can be PET, at a thickness of 3Opm, a PA6 or coPAIPE 40/60 co-extrusion, at a thickness of 3Opm or a PA6 or coPA/PP 40/75 co-extrusion, at a thickness of 3Opm, employing a 4g/m2 of mono-component, polyurethane based, solvent-free adhesive, or a material of equivalent properties and performance and then wound on to a core as a temporary holding stage.

In the fourth stage of the manufacturing process the components produced during the first three stages are brought together horizontally as indexed, overlying webs.

The lowest of the three webs produced is the now thermoformed layer of the lower face of the envelope forming the outer chamber, in which the cavities are each index pre-charged with an identical, small section of the Pd loaded substrate.

The middle of the three webs produced is the now thermoforrned layer of the lower face of the envelope forming the inner chamber, in which the cavities are each index pre-charged with an identical weight of the hydrogen generating fill material.

The upper of the three webs produced is the wadding fabric, over-layered with a selected polymer film facing.

The overall dimensions of the cavities produced in the piano-concave thermoforming of the lower face of envelopes forming the inner and outer chambers respectively, reflect the sizes of the caps and closures of the beverage packaging concerned.

The three webs are brought together, with the cavities of the outer envelope accurately aligned with those of the inner envelope layer and then bonded together around the circumference of the of the cavities by one of the alternatives of heat bonding, ultrasonic welding or dielectric welding.

In this format, the device can be manufactured by employing modifications to existing horizontal or vertical thermoform and lamination process, in which the several components, in web form, are bought together and bonded to produce a single material.

The device in an alternative embodiment, as a self-adhesive inclusion label, is manufactured following the same process as the caps and closure inclusion insert but with the wadding fabric, over-layered with a selected polymer film facing, being replaced by a self-adhesive coated polymer film layer, which is an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase, which can be PET, a PA6 or coPAt PE 40/60 co-extrusion or a PA/PP 40/75 co-extrusion and is overlaid by an adhesive protecting, peelable, non-woven, cellulose based fabric In this format, the device can be again manufactured by employing modifications to existing horizontal or vertical thermoform and lamination process, in which the several components, in web form, are bought together and bonded to produce a single material.

The device in a further alternative embodiment, as a sachet inclusion, is again manufactured by the same general process, but with the upper face of the inner chamber, as an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase, which may be fabricated from PET, a PA6 or coPA/PE 40/60 co-extrusion or a PA6 or coPAIPP 40/75 co-extrusion, carries no additional layers of either wadding or self-adhesive coating.

In this format, the device can be manufactured employing existing technology in the form of a modified form, fill and seal process, in which the several components, in web form, are bought together and bonded to produce a complex sachet.

In this format, the device is intended to be placed and secured, in a pre-determined position, on the inner surface of the primary packaging of the packed product.

The size and thus the exposed surface area of either of the latter two formats of the device is designed to effect the oxygen scavenging pack atmosphere control required and is thus specific to the product packed and will therefore vary from product to product.

The size and thus the exposed surface area of either of the formats of the device is designed to effect the shelf life required and is thus specific to the product packed and will therefore vary from product to product.

Claims

Claims 1. A hydrogen generating and palladium catalysed, oxygen absorbing device for a food packaging inclusion, comprising: a first chamber and a second chamber having envelopes being impermeable to water in the liquid phase but permeable to water vapour and gases; the first chamber containing a fill material formulation, which when activated by water vapour, generates hydrogen, the second chamber containing a substrate carrying a deposit of finely divided palladium, for catalysing the reaction between the generated hydrogen and oxygen to remove oxygen for allowing the establishment and maintenance of an oxygen free atmosphere within the headspace of bottles, cans, sachets or cartons of aqueous liquid foods and beverages.
2. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 1, wherein the envelopes are formed of walls comprising a lamination of a plurality of layers.
3. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 1 or 2, wherein the first and second chambers are aligned in parallel and immediately adjacent to one another.
4. A hydrogen generating and palladium catalysed, oxygen absorbing device according to any preceding claim, wherein the fill material formulation comprises: a water vapour reacting, hydrogen generating metallic element or compound, and a competitive water vapour absorbing material, for controlling the rate of reaction.
5. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 4, wherein the fill material formulation comprises in a powdered format, potassium, magnesium, zinc or aluminium.
6. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 4, wherein the fill material formulation comprises water vapour reacting, hydrogen generating metallic hydrides, in a powdered format, preferably including at least one of sodium hydride, magnesium hydride and calcium hydride
7. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 4, wherein the fill material formulation comprises water vapour reacting, hydrogen generating metallic borohydrides, in a powdered format, preferably including include sodium borohydride and lithium borohydride.
8. A hydrogen generating and palladium catalysed, oxygen absorbing device according to any preceding claim, wherein the envelope of the first chamber is in two parts, having an upper face and a lower face, the upper face being an effective barrier to water vapour and gas transmission and a fully effective barrier to water in its liquid phase, of polyethylene terephthalate (PET), a polyamide (PA)/polyethylene (PE) 40/60 co-extrusion or a PA/polypropylene (PP) 40/75 co-extrusion.
9. A hydrogen generating and palladium catalysed, oxygen absorbing device according to any preceding claim, wherein a lower face of the envelope of the first chamber also forms the upper face of the envelope of the second chamber, and is both permeable to water vapour and gases and a fully effective barrier to water in its liquid phase.
10. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 9, wherein the lower face of the envelope of the first chamber also forms the upper face of the envelope of the second chamber is a bi-laminate material, comprising an upper, permeable layer of Tyvek 1025B, a spun-bonded, opaque, 42.5g1m2, high density polyethylene (HDPE) fabric, bonded with a 4g/m2 of mono-component, polyurethane based, solvent-free adhesive, to a water impermeable layer of a PA as PA6 or copolymer PA (coPA) film, 8pm -2Opm in thickness, which is liquid water impermeable and has a WVTR in the range of 80g-120g/m2/24hr © 23°C & 85%RH and an OTR in the range of 1 OOcm3-600cm3/m2/24hr/bar © 23°C.
11. A hydrogen generating and palladium catalysed, oxygen absorbing device according to any preceding claim, wherein the second chamber accommodates a section of a non-woven fabric or a porous metallic oxide based substrate carrying a deposit of finely divided palladium designed to catalyse the reaction between hydrogen and oxygen, with water being the reaction product.
12. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 11, wherein the palladium catalyst is in the form of a finely comminuted palladium metal on: a non-woven, fibrous, polyacrylate polymer fabric substrate, adsorbed on to a zeolite and applied as a thin coating on a polymer film, on a non-woven, fibrous, polypropylene polymer fabric substrate, or on a porous aluminium oxide based substrate.
13. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 12, wherein the particle size of the palladium catalyst is from 0.1 pm to O.5pm in diameter.
14. A hydrogen generating and palladium catalysed oxygen absorbing device according to claim 12 or 13, wherein the palladium catalyst is deposited on the substrate at a loading density of approximately 0.1 to 0.2 mg/cm2.
15. A hydrogen generating and palladium catalysed, oxygen absorbing device according to any preceding claim, wherein the lower face of the envelope of the second chamber is both permeable to water vapour and gases and a fully effective barrier to water in its liquid phase.
16. A hydrogen generating and palladium catalysed, oxygen absorbing device according to claim 15, wherein the lower face of the envelope of the second chamber is a bi-laminate material, comprising an upper, permeable layer of Tyvek 1025B, a spun-bonded, opaque, 42.5g1m2 HDPE fabric, bonded with a 4g1m2 of mono-component, polyurethane based, solvent-free adhesive, to a water impermeable layer of a PA6 or coPA film, 8pm -2Opm in thickness, which is liquid water impermeable and has a WVTR in the range of 80g-120g1m2124hr © 23°C & 85%RH and an OTR in the range of lOOcm3-600crn3/m2124hr/bar © 23°C.
17. A method of manufacturing a hydrogen generating and palladium catalysed, oxygen absorbing device according to any preceding claim, comprising: bringing together three webs to form a composite laminate material., wherein the lowest of the three webs forms the lower face of the envelope forming the second chamber, in which the the lowest of the three webs is pre-charged with an sections of the palladium loaded substrate, the middle of the three webs forms the lower face of the envelope forming the inner chamber, in which the middle of the three webs is pre-charged with the hydrogen generating fill material, and the upper of the three webs produced forms the wadding fabric, over-layered with a selected polymer film facing.
18. A method according to claim 15, wherein the lowest of the three webs includes a plurality of formed cavities index precharged with a weight of the palladium loaded substrate, and the middle of the three webs includes a plurality of formed cavities index precharged with a weight of the hydrogen generating fill material.
19. A food package, comprising a cap or closure, wherein the device of any of claims 1 to 14 forms the resilient structure of a seal to the cap or and closure to produce an air-tight and a liquid leak-proof' seal.