WO2004110873A2

WO2004110873A2 - Beverage package

Info

Publication number: WO2004110873A2
Application number: PCT/GB2004/002278
Authority: WO
Inventors: Simon Scott
Original assignee: J R Crompton Ltd
Priority date: 2003-06-13
Filing date: 2004-05-27
Publication date: 2004-12-23
Also published as: WO2004110873A3; GB0313708D0

Abstract

The present invention relates to a novel type of paper web and a beverage infusion package formed from the paper web. The package possesses good wet strength and resistance to bursting and allows beverages such as coffee which are sensitive to air to be stored for an extended period without degradation. The beverage infusion package may be of the heat seal or non-heat seal type and is formed from cellulosic material containing an antioxidant.

Description

BEVERAGE PACKAGE

The present invention relates to a novel type of beverage infusion package which allows the infusion product contained inside to enjoy an extended shelf life. In particular the infusion product is coffee or tea. The paper of the invention can thus be used in a whole range of coffee and tea beverage filtration packaging such as hard pods, soft pods, coffee pouches and systems in which a container incorporates the paper with the coffee. More particularly, the invention relates to coffee infusion packaging such as coffee bags. The present invention also relates to porous, fibrous web materials for use in producing beverage infusion packages which provide an extended shelf life for the infusion product. It is also possible to apply printing and/or a relief pattern to the package of the present invention.

Beverage infusion packages such as tea bags comprise a particulate beverage precursor material, e.g. tea leaves, in a bag, sachet, pouch or the like (all conveniently referred to herein as a bag) of a porous, fibrous cellulosic material. This material typically has a weight of 10 to 30gm^~2 and is often referred to as "tissue" or "tissue paper". The paper may be of the "heat seal" or "non-heat seal" type.

However, in the case of coffee it has not previously been possible to package individual portions of fresh ground coffee powder or granules in conventional packages such as those used for tea bags without also providing an outer wrapper for each individual package or losing the "fresh" flavour due to oxidative degradation of the coffee oils. Alternatively, coffee has traditionally been packaged in individual infusion packages made of metallised or plastics film. The reason for this is that coffee is more prone to oxidation by the atmosphere than tea. Thus individual coffee portions are usually packaged in sachets of metallised or plastic film and packed in an inert atmosphere in order to prevent degradation of the coffee over a period of time.

The present invention is concerned with the production of both heat-seal and non- heat seal coffee infusion packages based on conventional papers used in the manufacture of tea bags and coffee infusion packages, or papers containing a high percentage of wood pulp described herein which have their own particular advantages due to the high wood pulp content. In either case, the papers have been treated to impart the required properties but the papers also contain an antioxidant in accordance with the invention. The packages of the present invention consequently enjoy a good shelf life whilst providing convenience to the consumer.

Heat seal paper comprises a web of one or more layers. A single layer heat sealed paper contains cellulosic and thermoplastic fibres. In the case of webs having two or more layers, one layer may contain cellulosic fibres and the other layer may incorporate thermoplastic fibres which are to form the basis of the heat seal. In another arrangement the inner (structural) layer comprises both cellulosic fibres and thermoplastic fibres. The entrained thermoplastic fibres provide a stronger heat seal between two webs of the tissue paper because the thermoplastic forming the heat seal is an integral part of the structural layer. The second (outer) layer is an insulating layer of material whose primary function is to protect the rollers of the processing machinery from the thermoplastic-containing structural layer during processing.

United Kingdom patent no. 1091073 describes a heat sealable paper and a process of manufacturing the same. This patent describes the production of a heat sealable paper from a liquid dispersion of non- toxic and tasteless thermoplastic fibres having a melting point between 100⁰C and 240°C and non-thermoplastic cellulosic fibres.

Non-heat seal paper usually comprises a web of material which is a single layer of cellulosic fibres. A package is formed by folding the paper and forming a mechanical closure seam to seal the package.

Conventionally, both the heat seal paper and the non-heat seal paper are produced from cellulosic fibres produced from mixtures of well known paper-making fibres. Suitable fibres may include both wood and non-wood materials such as manila hemp, sisal, jute, bleached and un-bleached softwood and hardwood species, and sometimes compatible synthetic fibres such as viscose rayon and spun bonded rayon are also included. The web of paper material used as the basis for the paper of the present invention is typically manufactured by wet laid processes which are well known in the art. The paper material is generally treated with classic wet and dry strength chemical enhancing products such as carboxymethyl cellulose (CMC), polyamide epichlorohydrin, and melamine formaldehyde.

It is generally the case that paper suitable for the production of infusion packages contains around 70% of abaca or manila (which may include approximately 10% of sisal or jute.) A small quantity of wood pulp, typically about 30% by weight of the cellulosic material, is added as a filler. However, traditionally, it is important to ensure that the wood pulp is only present in a relatively small proportion, usually not greater than 20% by weight, in order not to detract significantly from the strength of the bag, and in particular from the properties of the bag when wet.

Conventional materials used in existing paper for the production of tea include abaca, manila, sisal and jute in conjunction with wood pulp. Synthetic fibres such as rayon can also be incorporated with the wood pulp.

Wood pulp differs from the above fibres in tending to be of much shorter length, with wood pulp typically being only half the length or less of fibres such as manila. In approximate numeric terms a manila fibre would typically be around an average of 4.5mm long whereas a wood pulp fibre of the type incorporated into a tea bag would typically be an average of 2.0mm. It is therefore widely appreciated in the art that increasing the amount of wood pulp present in the tissue paper leads to a substantial decrease in the strength of any package formed and in particular in the wet strength of the paper. The reduction in strength appears to decrease in linear relation to the increasing wood pulp content.

Coffee filters have previously been produced having a cellulosic fibre content which is 100% wood pulp. However, these products are very heavy grammage paper, typically greater than 50 gm^'2 and these materials act as a filter paper by allowing direct exposure of hot or boiling water with the solid beverage so that the filtrate passes through the paper due to gravity. These materials are open and are not formed into packages as is the case for beverage packages containing tea. If such a paper were to be made into a sealed product such as a beverage infusion package, the package simply would not function as an infusion package without additional force being applied. This is because the material is too heavy and is unable to allow the effective passage of liquid across it in the absence of, for example, gravitational force pulling liquid, or pressure pushing liquid, through the paper. These materials also would not be able to be processed on machines into beverage infusion packages.

To date individual portions of coffee have been provided in air-tight sachets made of plastics or metallised film and are packaged either in a vacuum or under a protective nitrogen atmosphere.

It is the aim of the present invention to provide a paper web which can be formed into packaging material which is suitable for packing individual portions of an infusion beverage. Ideally, the package should be ready for immediate use and yet also be able to be stored for an extended period of time. It is another aim of the inventor to provide a beverage package which comprises the paper web of the invention together with an infusion product. It is a further aim that the beverage package contains an individual portion of the beverage such as coffee or tea for single use without the need for unwrapping the package. It is a further aim that the packaging material used to make the beverage package, and the beverage package itself, be biodegradable to at least some extent so that once the package has been used and disposed of by the consumer it will not have a deleterious effect on the waste stream and on the environment in general. It is also an aim that the package incorporates tissue paper to act as a filter.

More particularly, it is intended that the paper should be capable of use in both heat seal and non-heat seal packages. It is a further aim that the paper should have good wet and dry strength and be resistant to bursting so that the product is retained securely. It is thus an aim of the present invention to provide a beverage infusion package which retains its structural integrity. It is also desired that the resulting package has a good crimp strength once sealed to form a closed package. It is thus an aim of the present invention to provide a paper which can be used in the production of a non-heat sealed package eg a coffee bag having a high crimp strength and a resistance to failure. It is a further object of the invention to provide a package and a paper web for the production of a package which is easy to process and economical to produce. It is a further aim to produce a relatively light weight paper suitable for packaging or retaining coffee. Another aim is to produce a package formed from a paper web which is acceptable for use in food products. It is also an aim to provide a process for preparing the paper web used in the -package.

The present invention satisfies some or all of the above objects.

Another problem with prior art tea bags, particularly of the non-heat sealed type, is that they are prone to bursting because the crimp which serves to seal the bag is unable to cope with gas pressure when introduced to boiling water. This problem is exacerbated with increasing trend of users to introduce the bag into cold water and then apply microwave heating. This heating regiment is much more aggressive and increases the failure rate of tea bags and causes loss of the contents with the effect being most noticeable in non-heat seal tea bags. This problem has not been encountered with coffee bags as hitherto coffee has not been packaged in this manner. However, in one aspect of the invention, the coffee bags made using relatively low weight paper containing a high wood pulp content still exhibit a good burst strength when subjected to microwave heating or boiling water.

We have found that coffee, and other materials sensitive to the atmosphere upon standing for a long period of time, can be packaged in individual infusion packages using filter paper as described in this invention ready for immediate use. The antioxidant- containing paper of the present invention significantly improves the shelf life of the packaged beverage. It is possible to prepare a drink without the need to remove any other packaging associated with each individual portion. Of course, a number of such separate beverage - containing packages will usually be packaged together in a larger container such as a box or jar in the same manner that tea bags are conventionally offered for sale and these may be wrapped as a group and may be in an inert atmosphere.

The convenience of this arrangement provides a number of significant advantages. Firstly, there is a cost benefit because individual outer protective packaging in an inert atmosphere is no longer required in order to maintain the quality and stability of the product. Thus costly materials and processing time to produce them are avoided. Secondly, the reduction in packaging has an environmental benefit in that valuable resources are not being consumed and subsequently entering the waste stream. Thirdly, the absence of outer protective packaging for each individual beverage portion means that the product can be picked up and used immediately by a consumer without the need to unwrap the beverage portion. This is a significant benefit to the consumer in terms of convenience as it enables the consumer to prepare beverages such as coffee in exactly the same way and with the same ease as would be the case with tea bags.

Another problem with prior art beverage packages of the non-heat sealed type is that frequently they are required to be coated with latex in order to facilitate processing of the paper during the manufacture of the package. Such packages have the disadvantage that they float because latex is hydrophobic and infusion performance is reduced. In order to overcome this, these prior art packages frequently contain further additives in order to make them sink and restore infusion performance. The non-heat sealed packages of the present invention do not require a latex coating and thus also maintain good infusion performance and good storage properties without additional treatment steps other than incorporation of the antioxidant. For specific applications latex coatings may be of use and this may be incorporated with the package of the invention. There is also the advantage that the non-heat sealed packages of the present invention do not contain a large number of unnecessary additives and are thus simpler and more economical to manufacture.

We have also found in one aspect of the invention that it is possible to incorporate relatively high proportions of wood pulp into paper whilst maintaining or improving the wet strength of the paper. The paper can thus be used to produce beverage infusion packages such as coffee which have good wet and dry strength. We have also found that it is not necessary to include dry strength additives, in particular carboxymethyl cellulose (CMC) in the paper. The paper of the present invention has good dry strength in its own right without CMC being added.

The reasons underlying this finding are not understood although it is postulated that the shorter flatter ribbon-like fibres contained within the wood pulp result in the fibres laying together well. The increased surface area of the fibres may also lead to improved contact bonding between the fibres when folded. It is speculated that this may result in an improved strength in the paper both before and after crimping in a non heat-sealed bag. The resulting crimped product thus has improved strength and is less likely to fail due to pressure on exposure to boiling water.

According to one aspect of the present invention, there is provided a paper web of porous, fibrous, cellulosic material suitable for producing a beverage infusion package wherein the paper web has a grammage of 9 to lOOgm^"2 and incorporates one or more antioxidants in a total amount of from 0.01% to 50% by weight of the paper web.

Thus we have found that by incorporating an antioxidant into tissue paper or providing a covering of the antioxidant on the tissue paper enables a package to be produced which provides an extended shelf life for the food product contain within.

In an embodiment, the antioxidant is provided on one or both surfaces of the paper web. Preferably, the antioxidant is provided by spray coating, surface coating or printing. In another embodiment, the antioxidant is incorporated into the body of the paper web. Equally, the paper web may have both a surface coating of the antioxidant and contain antioxidant in the body of the web.

hi another embodiment the antioxidant is one or more selected from the group comprising: alkylphenols, hydroxy phenolpropionates, hydroxybenzyl compounds, alkylidene bisphenols, secondary aromatic amines, thio bisphenols, aminophenols, thioethers, phosphites and phosphonites, sterically - hindered amines, carotenoids, polyphenols, tea flavanoids or any compounds identified as acceptable in FDA REGULATIONS 21CFR Section 178.2010 or 178.2550. Thus any combination of the above can be used as the antioxidant.

Phenol-containing compounds are particularly preferred.

hi an embodiment, it is preferred that the antioxidant is one or more antioxidants selected from the group comprising: N-isopropyl-N'-phenylparaphenylene diamine; 4,4' thio bis (2-tertbutyl -5- methylphenol); phenol - 4 (4,6 - bis (octylthio) - 1,3 - triazine -2-yl) amino - 2, 6- bis (1,1- dimethylethyl); dilauryl thiodipropionate; tris (2,4 - ditertbutylphenyl) phosphite; bis (2,2',6' - tetra methylpiperidinyl) sebacate; alpha-tocopheral (vitamin E); and 2,6 - ditertbutyl -4- methylphenol. Of those antioxidants, alpha-tocopherol and 2,6- ditertbutyl -4- methylphenol are particularly preferred.

In a further embodiment, the amount of antioxidant in the paper is from 0.5% to 10% by weight of the paper web. This leads to excellent storage properties and shelf left for the food to be packaged whilst avoiding the need for a high loading of additive.

It is essential that the antioxidant is suitable for use in food products. Any antioxidant which has been approved for use in conjunction with food or which is capable of being used with food in accordance with regulatory requirements may be used in the paper of the present invention.

The paper web generally has a grammage of 9 to 100 gm^"2 and more typically in the range of 10 to 40gm^'2. It is preferred that the material has a grammage of from 10 to 30gm^"2 from the point of view of producing a package which has good dry and wet strength and which allows effective infusion of water into the package.

In another embodiment the web consists of a single layer of material. The non-heat seal paper of the present invention may also be produced by a dual layer process as described in our earlier patent no EP 0842043.

The incorporation of at least 65% by weight wood pulp in the cellulosic material used in one embodiment of the invention to form the paper web leads to an improved strength in the mechanical seam of a finished beverage package both when dry and when wet. The mechanical seam may be produced by conventional methods such as applying a mechanical compressive force using a toothed wheel to folded over edges of the web in a process conventionally known as crimping.

Hence, from the point of view of ensuring good dry and wet strengths, it is preferable that the wood pulp comprises at least 65% by weight of the cellulosic material. More preferably, the cellulosic material comprises at least 80% by weight wood pulp as this leads to a significantly improved wet strength. It is further preferred that the wood pulp comprises at least 90% by weight of the cellulosic material because this provides both good wet strength and ensures a strong mechanical seal when crimped. It is even possible for the paper web to be produced from cellulosic material containing 100% wood pulp.

In another aspect of the present invention, there is provided a beverage infusion package formed from a web of porous, fibrous, cellulosic material, wherein the web has a grammage of 9 to lOOgm^"2 incorporates an antioxidant in an amount of 0.01% to 50% by weight of the web, the package having a closure seam produced by a mechanical compression action without heat sealing.

In an embodiment the beverage infusion package may be a coffee bag or a tea bag. Preferably, the package is adapted for use as a coffee bag, coffee pouch, hard pod, soft pod or a plastics container incorporating coffee and the paper of the invention. The package will contain from 2 to 1Og of the infusion product, and typically around 5g.

In another aspect of the present invention, there is provided a beverage infusion package formed from a web of porous, fibrous, cellulosic material, wherein the web has a grammage of 9 to lOOgm^"2 incorporates an antioxidant in an amount of 0.01% to 50% by weight of the web, and wherein the web includes thermoplastic fibres.

The heat seal is formed when two paper webs which may be of the same or different composition containing thermoplastic fibres are brought together in the presence of heat. For example, a sheet may be folded to define a void, the void filled with a beverage and the edges then heat sealed or a paper web is sealed to a component of a beverage infusion package.

In a preferred embodiment, the web of porous material comprises a structural layer containing cellulosic material and thermoplastic fibres, and an insulating layer which is formed of cellulosic fibres. In an embodiment, the cellulosic component of the structural layer preferably contains at least 65% by weight of wood pulp in order to ensure adequate strength in the package. The relative proportions of cellulosic material and thermoplastics material are within conventional ranges. Any conventional "tissue-type" paper which is used as a base material for preparing infusion packages according to the present invention. Equally, the base material can be tissue paper containing a high proportion of wood pulp which we have developed.

Examples of suitable thermoplastics which may be used are polypropylene, polyester, polyamide 6, polyamide 66, polyamide 11, polyamide 12 and high density polyethylene. Blocked or random co-polymers or ter polymers of polypropylene and ethylene may also be used. Other suitable polymers include modified polyethylene copolymers, copolymers of vinyl chloride and vinyl acetate, polyethylene, polylactic acid, fibrils, bi-component fibres. Thermoplastic materials known as synthetic wood pulp or fibrils would also be suitable.

The thermoplastic fibres will preferably have a thickness of 0.5 to 6.0 denier although the best results are generally achieved with fibres in the 2 to 4 denier range.

The length of the thermoplastic fibres may be from 0.5mm to 12mm but preferably are in the range of 3 to 6mm in order to ensure compatibility with the wood pulp fibres.

The thermoplastic fibres in the web are preferably fused or thermally bonded together at a temperature greater than the crystalline melt temperature of the thermoplastic fibres. This assists in ensuring the structural integrity of the web.

The non-heat sealed paper described in one aspect of the invention may also incorporate thermoplastic fibres which may preferably be fused or thermally bonded together as above. The thermoplastic fibres may be amorphous or partially crystalline. We have found that the incorporation of these fibres also produces a significant enhancement in the mechanical seam integrity ie in the crimp strength.

In another embodiment of the present invention, the balance of the cellulosic material in the paper web which is not of wood pulp origin (if any) may be of natural origin and/or synthetic material. Natural materials which are suitable include abaca, manila, sisal, jute and hemp. Suitable synthetic materials include rayon. In principle, the wood pulp used in the present invention may be of any origin and may be hardwood or softwood. The important feature is that the pulp is capable of developing good strength at low levels of refining. Any wood pulp that has sufficient strength such that the paper web can be formed and processed at the desired weight ranges without rupture can be used in the package or web of the present invention. It is also important that the wood pulp retains porosity after refining. Usually, there is a conflict between increasing the degree of refining to develop strength and reducing the porosity of the resultant web as a consequence of increased refining. Refining is a conventional process applied to wood pulps and thus will not be described here.

We have found that certain wood pulps are advantageous. Specifically Northern Bleached Softwood Kraft (NBSK), black spruce pulp from British Columbia, Catawba pulp derived from Southern USA pine pulp and harmac pulp derived from coastal British Columbia western red cedar pulp. Other suitable pulps include Canadian pulps such as Miramichi newbrite (Newcastle New Brunswick NBSK), Squamish (British Columbia western red cedar pulp), Howe sound (coastal British Columbia NBSK), and Donahue St Felicien (NBSK from Quebec). Scandinavian pulps such at Botinia pine and Wisapine from Finland and Norland from Sweden are also suitable. Hardwood pulps such as Encel (Eucalyptus pulp from Spain), Caucas Betula (Birch pulp from Finland), Chesapeake (mixed hardwood from the USA), and Jari (Amazonian Eucalyptus pulp) can also be used particularly when blended softwoods to achieve the required properties. The key properties for the wood pulp are tensile breaking length, tear strength, porosity and bulk after refining.

Conventional additives such as wet and dry strength agents, sizing agents and fillers may be incorporated in the paper as required to give the paper desired properties. Thus wet strength agents, preferably in an amount of not more than 10% by weight, such as melamine formaldehyde and polyamide epichlorohydrin can be added.

This is particularly important in the case of a non-heat sealed package because it is important that the crimp remains intact during use. Traditionally crimp strength has been enhanced by adding thermoplastic materials to the paper even though the package is not heat sealed. This improves the crimp strength but has processing and cost disadvantages. However, the non-heat sealed package of the present invention does not require the addition of thermoplastic in order to enhance strength, although it is possible to incorporate thermoplastic material in the non-heat seal paper of the present invention used to form a non-heat sealed package should it be desired.

The manufacturing process for the paper which forms the basis for the paper of the present invention is conventional and thus will not be described here in detail. Briefly, the process involves dispersion of the fibrous material in water followed by mechanical treatment of the fibres (refining) in order to enhance the cross bonding between fibres. The next stage involves blending the fibrous components together and the addition of any necessary dry or wet strength chemicals. The liquid dispersion of fibre (stock) is then cleaned in hydra- cyclones to remove dense contrary material. The dilute stock is then screened. The paper web is formed by metering the very dilute stock onto an endless mesh (wire). The water is drained away and the wet web is carried forward to the drier part of the paper-making machine. The resulting wet paper web is dried by hot air and contact with steam heated cylinders or other drying methods and optional surface treatment of the paper surface is then performed. It is at this stage that functional chemicals such as sizing agents are added. Further drying, including curing of wet strength resins and thermal bonding of any thermoplastic component is then effected. The final stages of the process involve moisture correction with water or steam spray, calendaring to control the thickness or smooth the paper surface, and reeling the continuous web onto a roll.

The antioxidant or mixture of antioxidants can be added or applied to the paper at various different stages of the production process. Thus, in one embodiment the antioxidant is added to the paper stock before the formation of the paper web occurs. This allows the antioxidant to be incorporated in the body of the paper web. In another embodiment of the invention, the antioxidant is added to the paper web as a surface coating. This can be achieved by methods such as size pressing and blade coating. Alternatively, the coating can be applied by spray coating or by contacting the web with a solvent such as ethanol or addition of an emulsion containing the antioxidant. Alternatively, the antioxidant can be added by a printing process using a standard printing method which can be either water-based or solvent-based, hi another embodiment, the antioxidant can be incorporated in a polymer or other carrier agent which may release over time and then added to or incorporated in the paper web.

According to another aspect of the present invention, there is provided a process for incorporating an antioxidant into a paper web, the process comprising the steps:

(a) preparing a fibre stock;

(b) introducing an antioxidant into the stock in an amount corresponding to 0.01% to 50% by weight of the paper web; and c) forming a paper web from the stock

According to another aspect of the present invention, there is provided a process for preparing a paper web carrying an antioxidant, the process comprising the steps:

(a) forming a paper web from fibre stock, and

(b) contacting the paper web with an antioxidant so that the paper web includes 0.01% to 50% by weight of the antioxidant.

Suitable solvents for applying the antioxidant include both aqueous and non-aqueous solvents. Ethanol or water is particularly preferred.

The manufacture of beverage packages such as tea bags from the paper of this invention is achieved in the case of non-heat sealed paper by folding, crimping and stapling as described in our earlier patent No WO01/41610. hi the case of heat sealable papers, two webs of paper are placed together with their thermally active surfaces facing one another and then compressed between heated rollers. Ultrasonic or other suitable methods of sealing thermoplastic surfaces may also be used. The design of the roller surface controls the pattern of the heat seal obtained, e.g. round, square, pyramidal etc. The key variables are the temperature of the heated rollers, the pressure applied, the speed of the web, the condition of the rollers and the choice and quantity of thermoplastic material within the construction of the tea bag paper. However optimisation of appropriate heat sealing processing parameters for a given paper is entirely within the contemplation of the skilled person. It is envisaged that the papers of the present invention may find uses other than simply in beverage packages such as tea and coffee bags. Thus, it is believed that a strong lightweight wood pulp containing paper could be used in a number of alternative beverage packages or beverage filtration products.

In a further aspect of the present invention, there is provided the use of a web of porous, fibrous, cellulosic material, wherein the web has a grammage of 9 to 100 gm^"2 and includes cellulosic fibres and thermoplastic fibres and an antioxidant in an amount of 0.01% to 50% by weight of the web, and optionally wherein the cellulosic material in the web comprises at least 65% by weight wood pulp, in the manufacture of a beverage infusion package.

In the embodiment, the web of porous, fibrous cellulosic material may comprise a structural layer and a bonding layer. The structural layer includes cellulosic fibres and optionally thermoplastic, and the bonding layer includes cellulosic fibres and thermoplastic.

In an embodiment, the web may be produced to allow sealing on both sides of the paper for beverage infusion packages for machines that require sealing on both sides of the web.

Beverage infusion packages such as coffee bags and tea bags may be produced from the paper of the present invention by conventional processes. Thus, the bag is produced by folding, crimping and stapling as described in our earlier patent No WO01/41610. Thus, the processing steps described in that patent are directly applicable to the materials described in the present invention.

A heat sealed package may be produced in the manner described in our earlier patent No WO98/36128 and the processes described therein are directly applicable to the materials of the present invention. The paper and beverage packages of the present invention may thus be manufactured and processed in a conventional manner to packages made from conventional papers. Likewise, the paper used to make the beverage packages of the present invention may be embossed with a pattern in the manner described in our earlier patent No GB 2286159 and the processes described in that patent are directly applicable to the paper of the present invention.

The beverage packages of the present invention have the further advantage that printing may be applied to the package either for the purpose of decoration or for the purpose of identification despite the relatively high porosity of the paper. The printed beverage packages according to one embodiment of the present invention are specially designed so that the ink remains on the package. An ink approved for use in contact with food is used. In a further embodiment of the present invention the beverage package (either a heat sealed package or a non-heat sealed package) includes a printed region which remains visible after exposure to hot or boiling water.

Claims

1. A paper web of porous, fibrous, cellulosic material suitable for producing a beverage infusion package wherein the paper web has a grammage of 9 to lOOgm.^"2 and incorporates one or more antioxidants in a total amount of from 0.01% to 50% by weight of the paper web.

2. A paper web as claimed in claim 1 or 2, wherein the antioxidant is provided on one or both surfaces of the paper web and/or in the body of the paper web.

3. A paper web as claimed in 1 or 2, wherein the antioxidant is one or more selected from the group comprising: alkylphenols, hydroxy phenolpropionates, hydroxybenzyl compounds, alkylidene bisphenols, secondary aromatic amines, thio bisphenols, aminophenols, thioethers, phosphites and phosphonites, sterically - hindered amines, carotenoids, polyphenols, tea flavanoids or any compounds identified as acceptable in FDA REGULATIONS 21 CFR, Section 1278.2010 or 178.2550.

4. A paper web as claimed in claim 3, wherein the antioxidant is one or more selected from the group comprising: N-isopropyl-N'-phenylparaphenylene diamine; 4,4' thio bis (2-tertbutyl -5- methylphenol); phenol - 4 (4,6 - bis (octylthio) - 1,3 - triazine -2-yl) amino - 2, 6- bis (1,1- dimethylethyl); dilauryl thiodipropionate; tris (2,4 - ditertbutylphenyl) phosphite; bis (2,2',6' - tetra methylpiperidinyl) sebacate; alpha-tocopherol (vitamin E); and 2,6 - ditertbutyl -4- methylphenol.

5. A paper web as claimed in any of claims 1 to 4, wherein the amount of antioxidant in the paper is from 0.5% to 10% by weight of the paper web.

6. A paper web as claimed in any of claims 1 to 5, wherein the web has a grammage of from 10 to 30 gm^"2.

7. A paper web as claimed in any of claim 1 to 6, wherein the cellulosic material is at least 65% by weight wood pulp.

8. A paper web as claimed in claim 7, wherein the celhilosic material comprises at least 80% by weight wood pulp.

9. A beverage infusion package formed from a web of porous, fibrous, cellulosic material as claimed in any of claims 1 to 8.

10. A beverage infusion package as claimed in claim 9, wherein the web incorporates thermoplastic fibres.

11. A beverage package is claimed in claim 10, wherein the web of porous material comprises a structural insulating layer containing cellulosic material and a sealing layer containing a mixture of thermoplastic fibres and cellulosic fibres.

' 12. A beverage infusion package formed from a web of porous, fibrous, cellulosic material as claimed in any of claims 1 to 8, wherein the package has a mechanical closure seam which seals the package.

13. A process for incorporating an antioxidant into a paper web, the process comprising the steps:

(a) preparing a fibre stock;

14. A process for preparing a paper web carrying an antioxidant, the process comprising the steps:

(a) forming a paper web from fibre stock, and

15. The use of a web of porous, fibrous, cellulosic material, wherein the web has a grammage of 9 to 100 gm^"2 and includes an antioxidant in an amount of 0.01% to 50% by weight of the web, in the manufacture of a beverage infusion package.