GB2377890A

GB2377890A - Absorbent material with reduced malodour in use

Info

Publication number: GB2377890A
Application number: GB0118255A
Authority: GB
Inventors: Graham Steer; Padraig Troy; Jonathan Webb
Original assignee: Craig Medical Products Ltd
Current assignee: Craig Medical Products Ltd
Priority date: 2001-07-26
Filing date: 2001-07-26
Publication date: 2003-01-29
Also published as: GB0118255D0

Abstract

The present invention provides an absorbent material capable of absorbing fluid excreted from the body whilst preventing malodour. The absorbent material comprises an absorbing agent capable of absorbing fluid, and an oxidising agent such as sodium perborate.

Description

Absorbent Material The present invention relates to absorbent material, and in particular to absorbent material for absorbing fluid matter excreted from the body. Such material is useful in ostomy, incontinence or wound care, and the like. In particular, the present invention relates to the prevention of malodour once the absorbent material has absorbed the fluid.

Many of the fluids to be absorbed by the absorbent material of the present invention are themselves malodorous. Furthermore, material contained within the excreted fluid will tend to decompose, the decomposition generating malodorous gases. Frequently, the absorbent material within which the fluid is retained will be positioned near the body and are therefore maintained at a warm temperature. The warm temperature can lead to increased or accelerated decomposition of matter contained in the absorbed fluid.

Attempts have been made in the past to combat malodour, but with only limited success. One approach was to provide a masking fragrance. However, this has been found to have only limited effect. In GB-A-2301350, the inclusion of a preservative in the absorbent material was proposed. The preservative is intended to reduce the rate at which excreted materials decompose, thereby reducing malodour problems. An alternative approach proposed was the use of binding species that bind to the chemical molecules that are attributable to malodour, such binding rendering the malodorous molecules undetectable by human nasal organs.

Such binding species are commonly used in litter beds for pet animals.

It is the aim of the present invention to provide a more effective means of combating malodour in absorbent material. It has been found that the inclusion in the absorbent material of an oxidising agent, such as sodium perborate (NaB03), leads to a significant reduction in malodour.

It is essential that the oxidising agent used is one which is safe for contact with the skin. The oxidising agent used in the present invention should preferably also be stable, cheap and readily available.

Sodium perborate is a white powder or crystalline material which acts as a strong oxidising agent. It is also commonly used as a bleaching agent for textile bleaching and the like, and is even used to clean dentures. Although stable in cool, dry conditions, sodium perborate decomposes in a moist environment into sodium metaborate and hydrogen peroxide, with the gradual evolution of oxygen. This "activation"of sodium perborate in a warm and moist environment makes it ideally suited for use in connection with the absorption of fluids excreted from the body.

Other oxidising agents which might be used in the present invention include oxidising liquids such as hydrogen peroxide, and oxidising solids, in the form of powder, pellets, granules or the like, including potassium permanganate, sodium nitrate, potassium iodate and chlorine dioxide.

According to a first aspect of the present invention, there is provided an absorbent material comprising an absorbing agent and an oxidising agent, such as sodium perborate.

The oxidising agent can be included in the absorbent material by being dispersed within the absorbing agent used in the absorbent material. Alternatively, the oxidising agent is positioned adjacent to, but apart from, the absorbing agent.

When incorporating the oxidising agent into the absorbent material, it is important to note that when stored in moist conditions, oxidising agents tend to decompose.

Thus, if the absorbing agent is stored in a moist environment, the oxidising agent should be separated from the absorbing agent, in order to avoid undesired decomposition of the oxidising agent.

Where the oxidising agent is not simply dispersed within the absorbing agent, a convenient way to incorporate the oxidising agent in the absorbent material is to attach it to a supporting sheet. A water soluble or water dispersible bonding

adhesive is applied to the sheet and the oxidising agent, preferably in powder form, is sprinkled on and becomes adhered to the sheet, forming a product resembling sandpaper. A water soluble or water dispersible adhesive is used in order to ensure that the oxidising agent is released when the sheet is exposed to fluid, at which point the oxidising agent will be required to react with the fluid and become dispersed within the fluid for optimum results.

A wide variety of agents are known which are useful for absorbing fluid. Amongst the most effective agents are absorbent gelling materials, such as superabsorbents.

The absorbent gelling material can be natural, synthetic or modified natural polymers and materials. The absorbent gelling materials can be inorganic materials, such as liquid gels, or organic compounds, such as cross-linked polymers, or alginates, reticular carboxymethylcelluloses, grafted starches, natural modified polysaccharides or synthetic derivatives of acrylamides, acrylonitriles or polyacrylates.

Preferably, the absorbing agent used in conjunction with the present invention is a superabsorbent material and more preferably, it is sodium polyacrylate.

Small amounts of sodium polyacrylate are capable of absorbing a vast volume of fluid. The sodium polyacrylate swells upon absorbing fluid and its surface remains substantially dry to the touch. Sodium polyacrylate exhibits excellent fluid uptake and acquisition, making it particularly suited for use in incontinence articles, where rapid and high volume absorption of fluid is crucial.

A further advantage associated with the superabsorbent sodium polyacrylate, which comes in the form of a powder, is that it can be compressed to form a consolidated mass without significant loss of absorbency. Thus, articles incorporating this absorbing agent do not have to be bulky and can therefore be discrete, making them more attractive to users. Preferably, the formulation is compressed into tablets or between supporting sheets to form a relatively thin, sheet-like product.

The supporting sheets between which the absorbent formulation is sandwiched can be any material with high fluid penetration. The material may be woven or nonwoven, with or without synthetic fibres. One preferred material for use as the supporting sheets is cellulose tissue, and more preferably non-woven cellulose. The sheets are preferably between 10 and 100 gsm, with an open pore structure. This affords structural integrity, whilst allowing high fluid penetration. Where greater structural stability is required, thicker supporting sheets should be used, although the thicker sheets will tend to reduce absorbency to an extent. Clearly, various other materials may be used which have the appropriate properties for putting the present invention into practice.

In one embodiment of the present invention, the oxidising agent is dispersed within the absorbent formulation, which is then sandwiched between two supporting sheets.

In an alternative embodiment, oxidising agent is attached to a carrying sheet. In this embodiment, the sheet carrying the oxidising agent may be positioned next to one of the two supporting sheets between which the absorbent formulation is sandwiched. Alternatively, the oxidising agent is adhered to a surface of one of these two supporting sheets. The oxidising agent on the further sheet may either be adjacent to the absorbent formulation, or positioned so that it is not in direct contact with the absorbent formulation.

Preferably, when in use, the sheet carrying the oxidising agent will be positioned so that the absorbent formulation is between it and the source of fluid to be absorbed.

This avoids any reduction in the absorbancy of the absorbent material due to the sheet carrying the oxidising agent preventing penetration of the fluid into the layer of absorbent formulation. Even if the sheet carrying the oxidising agent is itself highly permeable to fluid, its permeability will be reduced if the sheet is covered with adhesive and oxidising agent.

According to one embodiment, the supporting sheet carrying the oxidising agent has high fluid permeability. For example, the material used can be the same as the supporting sheet used to sandwich the absorbent formulation, as described above.

In an alternative embodiment, the supporting sheet carrying the oxidising agent may have low permeability and serves as a seal, preventing the fluid from passing through and keeping the fluid in close proximity with the absorbing agent. In such an embodiment, the oxidising agent must clearly be attached to the surface of the sheet which is exposed to the fluid.

The absorbent material according to the preferred embodiments of the present invention may be produced using a simple process. The absorbent formulation is fed onto a travelling support sheet which is pulled off a supply roll. A second support sheet is fed from a second supply roll and these two sheets sandwich the absorbent formulation between them. The product passes between a pair of rollers, which compress the powder to form a consolidated product which will retain its integrity during normal handling.

Either a separate supporting sheet carrying the oxidising agent is then attached to the consolidated product, or one of the supporting sheets between which the absorbent formulation is sandwiched carries the oxidising agent.

The absorbent material according to the present invention can be incorporated into a variety of articles, such as incontinence pads, nappies, wound dressings, and the like.

It is also envisaged that additional agents are incorporated into the absorbent material of the present invention. For example, the material could include other agents which will help to combat malodour. Thus, malodour-counteracting agents known from the prior art may be included, such as fragrances or preservatives.

Alternatively or additionally, agents having other activity could be incorporated. In one embodiment, the absorbent material of the present invention further includes

an agent having bacteriostatic and bactericidal activity, such as aluminium sucrose octasulphate, which is also known as sucralfate. In another embodiment, anti-biotic and anti-microbial agents could be included.

Depending on the additional agents'compatibility with the absorbent formulation, they may be mixed in with the absorbent formulation, or incorporated by being adhered to a separate supporting sheet which is positioned adjacent to the absorbent formulation. The additional agent and the oxidising agent can be adhered to the same supporting sheet which is then either used to sandwich the absorbent formulation, or is attached to one of the supporting sheet used to sandwich the absorbent formulation.

Embodiments of the invention are now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram showing the production of the consolidated mass which forms part of the absorbent material according to one of the preferred embodiments of the present invention; Figures 2 to 4 are schematic cross-sectional views of three different embodiments of the invention; and Figure 5 is a schematic diagram of the supporting sheet carrying the oxidising agent.

As shown in Figure 1, the absorbent powder formulation 20 is fed onto a travelling supporting sheet 18 which is pulled from a supply roll 14. A second supporting sheet 16 is fed from a second supply roll 12 and these two sheets sandwich the absorbent formulation between them. The sheets and formulation pass between a pair of rollers 22,24, which compresses the powder between the sheets into a consolidated mass 10.

Figure 2 shows a cross-section of absorbent material according to one embodiment of the present invention. The material comprises the absorbent formulation 20 sandwiched between two supporting sheets 16,18. Attached to one supporting sheet 18 is a further supporting sheet 26, to which oxidising agent 28 is adhered by a water soluble or water dispersible adhesive.

Figure 3 shows an alternative embodiment, where one supporting sheet 18, between which the absorbent material is sandwiched, carries the oxidising agent 28. The oxidising agent is on the outer surface of the sheet, so that it is not in direct contact with the absorbent formulation 20.

Figure 4 shows the oxidising agent 28 dispersed throughout the absorbent formulation 20.

Figure 5 shows the supporting sheet 26 carrying the oxidising agent 28. The oxidising agent is adhered to one surface of the sheet, forming a surface resembling sandpaper.

Once the absorbent material according to the present invention has been manufactured, it can be cut into pieces of the desired shape and size, for incorporation into articles such as incontinence pads, nappies, wound dressings and the like.

According to a second aspect of the invention, articles are provided, such as incontinence pads, nappies, wound dressings and the like, which include the absorbent material according to the first aspect of the present invention.

The specific examples discussed above are merely preferred embodiments of the

.. present invention.

Claims

Claims 1. An absorbent material comprising an absorbing agent capable of absorbing fluid, and an oxidising agent.
2. An absorbent material as claimed in claim 1, wherein the oxidising agent is sodium perborate.
3. An absorbent material as claimed in either of claims 1 or 2, wherein the oxidising agent is not in direct contact with the absorbing agent.
4. An absorbent material as claimed in claim 3, wherein the oxidising agent is adhered to a supporting sheet.
5. An absorbent material as claimed in claim 4, wherein the oxidising agent is adhered to the supporting sheet by a water soluble or water dispersible adhesive.
6. An absorbent material as claimed in either of claims 1 or 2, wherein the oxidising agent is dispersed within the absorbing agent.
7. An absorbent material as claimed in any one of claims 1-5, wherein the absorbing agent is sodium polyacrylate.
8. An absorbent material as claimed in claim 7, wherein the absorbing agent is incorporated in an absorbent formulation.
9. An absorbent material as claimed in claim 8, wherein the absorbent formulation is compressed to form a consolidated mass.
10. An absorbent material as claimed in claim 9, wherein the absorbing agent is positioned between two supporting sheets.

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11. An absorbent material as claimed in claim 10, wherein the supporting sheets have high fluid penetration.
12. An absorbent material as claimed in either of claims 10 or 11, wherein the supporting sheets are cellulose tissue.
13. An absorbent material as claimed in any one of claims 10-12, wherein the supporting sheets are between 10 and 100 gsm.
14. An absorbent material as claimed in any one of claims 10-13, wherein one of the supporting sheets has the oxidising agent adhered to it.
15. An absorbent material as claimed in any one of claims 10-13, wherein an additional supporting sheet with oxidising agent adhered to it is positioned adjacent to one of the two supporting sheets between which the absorbing agent is positioned.
16. An absorbent material, substantially as hereinbefore described, and as shown in Figures 2 and 3.
17. An absorbent product incorporating an absorbent material as claimed in any one of claims 1 to 16.
18. A product as claimed in claim 17, comprising an incontinence pad, a nappy or a wound dressing.