WO2002047998A1

WO2002047998A1 - A packaging tube

Info

Publication number: WO2002047998A1
Application number: PCT/GB2001/005498
Authority: WO
Inventors: John Robinson
Original assignee: Dynamic Products Limited
Priority date: 2000-12-13
Filing date: 2001-12-13
Publication date: 2002-06-20
Also published as: GB0030436D0; AU2002222188A1

Abstract

A water soluble packaging tube for storing and/or dispensing a consumable product either as a supporting core for products such as, for example, toilet paper, kitchen wipes, aluminium foil or other products formed as a continuous roll or a as a container for foodstuffs comprises a base material of water soluble plastics material, such as polyvinyl alcohol, and at least one active ingredient, which assists the physical break up the tube on contact with water. The tube dissolves rapidly in water and may, therefore, be discarded after use by simply by dispensing it into a waste water system.

Description

A PACKAGING TUBE

The present invention relates to a water soluble or rapidly dispersible packaging tube for storing and/or dispensing a consumable product and more particularly to a packaging tube of the kind that is used as a core on which other material such as, for example, toilet or kitchen tissue, cleaning wipes, foil or protective film (e.g. clingfilm (RTM)) is wound. The packaging tube may alternatively be used as a packaging container for foodstuffs (e.g. crisps or confectionery) or sanitary items such as tampons. For the sake of clarity, the following description will make reference only to toilet tissue, however, it should be recognised that many other applications are also possible. Traditionally toilet tissue is sold, at retail outlets, on a wound paper or cardboard core, said core being in the form of a tube. It has long been an issue that the majority of used toilet roll cores are disposed of in land fill sites where they biodegrade, but the products of this degradation remain trapped in the landfill site or escape as gases, both of which are undesirable from an environmental viewpoint. A further issue is what happens when a toilet roll is used up, namely the core is often left on the dispenser in the bathroom because it requires disposal in a separate waste container.

A number of previous attempts have been made to develop water soluble or water disposable cores for toilet rolls, tampon applicators and the like, all of which have certain drawbacks which will be outlined below. US 4,872,933 (TEWS) describes a "...tampon applicator tube which can rapidly disintegrate in water...", the tube disclosed therein is a multi-layer, laminate core wound on a mandrel, said layers comprising at least one web of paper, one web of adhesive film and one web of super-absorbent material, the whole being heat sealed together under pressure, the web of super-absorbent material preferably being perforate and the adhesive preferably being water soluble. However, rather than a genuine dissolution/dispersion of the materials used to make the tube, all that is claimed is a rapid delamination of the wound tube. Whilst this does represent an improvement over a traditional toilet roll core, it is not considered to be a genuine solution the problems outlined above.

WO99/02083 (PAPESCHI) and JP9118478 (KEIO SEISHI KK) both take a similar approach, again basing their tubular cores on a traditional wound cardboard core. Both disclose the impregnation of at least a part of the cardboard tube with a "septic activator" bacterium, said bacterium being in a dormant state until such time as the core is disposed of into a water course, at which time said bacterium accelerates the decomposition of the cardboard. It is also suggested that the tube may further be impregnated with an organic nourishing agent for the bacterium (KEIO) and a perfumed compound (PAPESCHI). Again, whilst both of these products undoubtedly offer some improvement over a traditional cardboard core, it is unlikely that the bacterium will multiply enough or be active enough to rapidly disperse the core prior to flushing. Also, there is a potential health hazard if the cores are used by children for play or educational modelling purposes or if the cores are accidentally ingested by children. Other examples of perfuming toilet roll cores can be found in GB 2,276,548 (MONDAS) and GB 2,330,071 (LIVERSAGE), however, neither relates to the disposability of the cores, rather, they are directed towards providing an air freshener/toilet roll core combination package.

US 5,954,683 (DOWNS) and US 5,804,653 (WENG) both disclose disposable tampon applicators made predominantly from polyvinyl alcohol, with the addition of plasticisers and antioxidants and, optionally other ingredients. The DOWNS patent requires two different polyvinyl alcohols and preferably a water insoluble outer coating, whereas the WENG patent requires the use of an oxa acid plasticiser. Whilst both patents provide water soluble materials, there is no drive to break up the products, thereby accelerating their dissolution/dispersion into the water course. US 5,916,969 (WANG) and US 4,900,299 (WEBB) both disclose biodegradable tampon applicators made from a blend of polyolefms and poly (ethylene oxide); and a poly 3- hydroxybutyric acid composition respectively, whereas US 5,350,354 (BILLMERS) discloses a tampon applicator made from a modified starch compound (with a plasticiser), a material suggested for use in combination with polyvinyl alcohol in US 5,804,653 (WENG). However, the above products also suffer from the same shortcomings as the DOWNS and WENG patents described above.

The terms polyvinyl alcohol and polyvinyl alcohols, as used herein, are intended to include a wide range of both molecular weights, polydispersities and degrees of hydration of polyvinyl alcohols. The dividing line between a polyvinyl alcohol and a polyvinyl acetate is not clearly defined, each of the above factors being taken into consideration, however the term as used herein is intended to encompass both polyvinyal acetates as well as polyvinyl alcohols, and the foregoing description should be read with this in mind.

The packaging tube of the present invention attempts to overcome the above problems and shortcomings of the prior art by providing a packaging tube for storing a consumable product, the tube being composed of at least a water soluble plastics material and at least one active ingredient, said at least one active ingredient serving to physically break up the tube on contact with water, thereby increasing the exposed surface area prior to dissolution dispersion.

The tube may further comprise a water soluble starch.

The at least one active ingredient may physically break up the tube on contact with water by virtue of an effervescent action.

The at least one active ingredient may be a binary pair of reactants, reaction of which occurs in an aqueous medium generating volumes of gas which cause the aforementioned effervescence.

The binary pair of gas generating reactants are preferably an acid and an alkali, more preferably sodium bicarbonate and citric acid, however, any non-toxic, child safe binary combination of a carboxylic acid and a carbonate would perform in a similar manner to citric acid and sodium bicarbonate.

The binary reactants may be present in stoichiometric quantities as far as their reaction is concerned. One of the binary reactants may be provided in excess in order to accelerate the reaction between them. Either component being present in excess would also provide a degree of antibacterial action, since the majority of bacteria found in a toilet bowl prefer a substantially pH neutral environment.

Preferably the acidic component is provided in excess, as this would also combat lime scale formation in the toilet bowl. If the acid is citric acid then providing it in excess would also leave unreacted citric acid, which has a fresh odour, thereby providing a degree of added freshness to the toilet bowl.

The at least one active ingredient may physically break up the tube on contact with water by virtue of having a greater rate of expansion, in water, than the bulk'of the tube material. The packaging tube may further comprise a fragrance substance. The fragrance substance may be designed to be released only upon contact with water.

The packaging tube may further comprise a plasticiser or lubricant which may be selected from the group comprising glycols, glycerols and stearates. The packaging tube may further comprise other filler materials, such as calcium carbonate

The packaging tube may comprise a monolayer product, said layer comprising an admixture of the starch, the water soluble plastics material and the at least one active ingredient. Alternatively, the at least one active ingredient may be added after the tube has been formed, or in the case of more than one active ingredient being present, one or more of the active ingredients may be present in the initial admixture and one or more other of the active ingredients may be added after the tube has been formed.

The packaging tube may comprise a number of layers, different layers varying in their composition. The packaging tube may comprise two layers, a first layer comprising an admixture of the starch, the water soluble plastics material and one of the binary reactants, the second layer comprising an admixture of the starch, the water soluble plastics material and the other binary reactant.

The packaging tube may comprise three layers, the inner and outer layers being the same as described above with a third, barrier layer interdisposed between the other two layers, thereby preventing cross contamination of the binary reactants and removing the possibility of premature reaction during manufacture.

The packaging tube may comprise four layers, the structure being the same as the three layer tube described above, with the addition of a further barrier layer on either the inside or the outside of the tube.

The packaging tube may comprise five layers, the structure again being the same as the three layer tube described above, with the addition of a barrier layer to both the inside and the outside of the tube. The barrier layer(s) may be composed of the same substance as the water soluble plastics material.

The barrier layer(s) may comprise an adhesive, acting to bind adjacent layers together, whilst providing a barrier to mixing of their ingredients. The adhesive is preferably a water soluble adhesive.

The water soluble plastics material preferably comprises a polyvinyl alcohol, a blend of polyvinyl alcohols or a blend of one or more polyvinyl alcohols with ethylene vinyl alcohol.

The packaging tube is preferably formed by extrusion. In the case of the multilayer products described above, the different layers may be supplied to the same extrusion die by different extruder screws.

The packaging tube may be formed in the same manner as a traditional toilet roll core, that is by the wrapping of one or more webs, along with an adhesive, about a mandrel to form a tube. The one or more webs may be of the same or differing composition and may incorporate the at least one active ingredient, alternatively the at least one active ingredient may be present in the adhesive used to glue the core together. The individual webs are preferably produced via an extrusion process.

When the at least one active ingredient comprises a binary pair of reactants, the tube may be formed from separate layers, each layer containing only one of the binary reactants. Alternatively, if the manufacture of the tube is in non-aqueous (or low water) conditions a single layer may contain both binary reactants. In another alternative, the basic tube material may contain one of the binary reactants, the other being added after the tube has been produced, possibly in the form of a coating. In yet another alternative, the basic tube material may contain neither of the binary reactants, both being added after the tube has been formed.

A specific embodiment of the present invention will now be described, by way of example only.

An exemplary packaging tube according to the present invention is composed of a base water soluble composition of 10-15% polyvinyl alcohol and 85 to 90% modified starch e.g. maize, tapioca or barley starch along with trace amounts (of the order of 1%) of plasticiser and water. The polyvinyl alcohol is water-soluble and provides that composition with flexibility (enhanced by the addition of a plasticiser) and toughness whereas the starch provides bulk and mechanical stiffness. The composition thus simulates the properties of cellulose based materials.

The tube is formed using a three screw extruder, the screw feeding the outer layer 1 being loaded with the base composition plus approximately 1% w/w citric acid, the screw feeding the inner layer 3 being loaded with the base composition plus approximately 0.5% w/w sodium bicarbonate and the screw feeding the middle layer 2 being fed with a polyvinyl alcohol. The inner and outer screws are of equal volume and therefore produce layers of equal volume (assuming a uniform density of material), whereas the middle screw is of much smaller dimensions, producing a relatively thin barrier layer between the inner and outer layers. The extrudate is fed through a co-extrusion, multi-layer pipe die to produce an expanded, tubular structure. The two base layers will become somewhat foamed during the extrusion as a result of bubbles being formed by evaporating water, the polyvinyl alcohol forming a tubular film between them. The continuous extrusion is then cooked and cut to length.

The tube can be used as a core on which consumable products in the form of continuous rolls may be wound. Examples of such products are toilet paper, kitchen wipes, aluminium or tin kitchen foil, storage film material such as clingfilm (RTM) etc. Alternatively the tube may be used as an outer container for food products such as, for example, crisps, biscuits or confectionery or for other products. The tube can also be used in other forms of packaging such as, for example, an applicator tube for a tampon. It is to be understood that the examples referred to in this specification are not intended to be exhaustive and there may be other packaging applications.

When the consumable product has been used the tube may be discarded by disposing of it in a waste water system. For example, the core of a toilet roll may simply be dropped into the toilet bowl. On contact with water, the citric acid and the sodium bicarbonate start to dissolve instantly, the reaction between the two producing effervescence, this effervescence accelerates the break up of the base material in the bowl. This break up of the base material increases the exposed surface area, thus allowing more of the citric acid and the sodium bicarbonate to dissolve. Since the tube is solely composed of water-soluble materials it dissolves entirely in the water. Moreover by virtue of the presence of an excess of citric acid, lime scale is prevented from forming in the bowl, lime scale already present is reduced, bacterial propagation is reduced, or even eliminated, and a fresh, citron aroma remains.

In a second embodiment according to the present invention, two different webs are formed, the first comprising a blend of polyvinyl alcohol, plasticisers and citric acid, the second comprising a blend of polyvinyl alcohol, plasticisers and sodium bicarbonate. The two webs are formed into a tube in the traditional manner, by being wrapped around a mandrel and bonded together with an adhesive, the adhesive in this instance being a polyvinyl acetate based, water soluble adhesive. The tube is then used as the core for a consumable product, such as toilet paper, which is wound thereon. After the toilet roll has been used, the core can be safely disposed of in the waste water system.

It will be appreciated that all products are non-toxic and therefore are not hazardous to children or pets etc.

It should be recognised that the preceding description is given by way of example only and is in no way intended to limit the scope of the invention, which is defined in the appendant claims.

Claims

1. A packaging tube for storing and/or dispensing a consumable product, the tube being composed of at least a water soluble plastics material and at least one active ingredient, said active ingredient serving to physically break up the tube on contact with water.

2. A packaging tuba according to claim 1, wherein the packaging tube further comprises a water soluble starch composition.

3. A packaging tube according to claim 1 or 2, wherein the at least one active ingredient physically breaks up the tube, on contact with water, by virtue of an effervescent action.

4. A packaging tube according to claim 3, wherein the at least one active ingredient comprises a binary pair of reactants, reaction of which occurs in an aqueous medium, generating a gas which causes the effervescence.

5. A packaging tube according to claim 4, wherein the binary reactants comprise an acid and an alkali.

6. A packaging tube according to claim 5, wherein said binary reactants comprise citric acid and sodium bicarbonate.

7. A packaging tube according to claim 1, wherein the at least one active ingredient physically breaks up the tube, on contact with water, by virtue of having a greater rate of expansion, in water, than the bulk of the tube material.

8. A packaging tube according to any preceding claim, wherein the tube composition further comprises a fragrant substance.

9. A packaging tube according to any preceding claim, wherein said tube further comprises a plasticiser.

10. A packaging tube according to any preceding claim, wherein said tube comprises a plurality of layers, different layers varying in their composition.

11. A packaging tube according to any preceding claim, wherein said water soluble plastics material comprises a polyvinyl alcohol.

12. A packaging tube according to any preceding claim, wherein said water soluble plastics material comprises a blend of polyvinyl alcohols.

13. A packaging tube according to any preceding claim, wherein said water soluble plastics material comprises a blend of one or more polyvinyl alcohols with ethylene vinyl alcohol.

14. A packaging tube according to any preceding claim, wherein said tube is formed by an extrusion process.

15. A packaging tube according to any of claims 1 to 13, wherein said tube is formed by the wrapping of one or more webs, along with an adhesive, about a mandrel to form a tube.

16. A packaging tube substantially as hereinbefore described, with reference to the preceding description and Figure.