GB2321216A

GB2321216A - Absorbent materials

Info

Publication number: GB2321216A
Application number: GB9700892A
Authority: GB
Inventors: Roger Alan Chapman; Susan Gwynneth Johnson
Original assignee: Texon UK Ltd; British United Shoe Machinery Ltd
Current assignee: Noxet UK Ltd
Priority date: 1997-01-17
Filing date: 1997-01-17
Publication date: 1998-07-22
Also published as: GB9700892D0

Abstract

An absorbent material suitable for incorporation within incontinence and wound dressing products comprises a first layer of substantially hydrophobic fabric and a second layer of substantially hydrophilic fabric, which layers are secured together by fibre pegs extending between them. The absorbent material is impregnated with an anti-bacteria binding, including a binding polymer and solid or liquid anti-bacterial agents. Alternatively the absorbent material comprises a base absorbent fabric including an anti-bacterial binder washed into the base fabric in order to give up to 0.5% by weight concentration of liquid anti-bacterial liquid within the fabric. As a further alternative the absorbent material comprises a non-woven base absorbent fabric incorporating between 5 and 25% by weight of anti-bacterial fibres appropriately consolidated by fibre entanglement techniques.

Description

ABSORBENT MATERIALS The present invention relates to absorbent materials and more particularly, but not exclusively, to absorbent materials which are used to absorb potentially foul smelling liquids and exudates such as urine, blood and wound puss.

It is well known that wound dressings can help and facilitate wound healing by preventing ingress of contaminant particles to the wound site, providing a warm environment to propagate wound recovery, and by absorbing excess exudate to ensure the wound is in the best condition for healing. Furthermore, there are a wide range of incontinence products which allow absorption of urine etc.

whilst ensuring the source of such liquids remains relatively dry and so less susceptible to sores etc.

Unfortunately, such exudates, puss and excreted liquids rapidly begin to emit foul smells which are unacceptable and may result in removal of the wound dressing or the incontinence product before complete sage of that product or at least prematurely for comfort.

It will be appreciated that a significant cause of such foul smelling odours is the activity of bacteria in effect digesting products within the liquid exudate or puss and themselves emitting noxious gases which are perceived as the foul smells.

One obvious solution with regard to preventing foul smells is to ensure the absorbent material from which the incontinent or wound dressing product is manufactured incorporates bleach and other cleaning products. However, unfortunately, bleach in itself is an irritant and can have detrimental effects upon the fibres from which the bulk of absorbent materials are manufactured. Furthermore, it will be understood that bleach etc is relatively easily transported to the wound site in the liquid of the exudate etc.

It is an objective of the present invention to provide an absorbent material suitable for incorporation within incontinence and wound dressing products which includes anti-bacterial agents incorporated in such a way that such agents remain within the material and inhibit bacteria propagation and thus diminish their emission of noxious gases and so extend the life, both actual and acceptable of the product made from, such absorbent material.

In accordance with the first embodiment of the present invention there is provided an absorbent material comprising a first layer of substantially hydrophobic non-woven fabric and a second layer of substantially hydrophilic non-woven fabric, said first layer and said second layer being secured together by fibre pegs extending between said first layer and said second layer, said absorbent material being impregnated with an anti-bacteria binding including a binding polymer and solid or liquid anti-bacterial agents, said polymer binder securing said particulate anti-bacterial agent within said combined first non-woven fabric and said second non-woven fabric in a dispersed manner in accordance with wash impregnation.

Preferably, the absorbent material comprises said second substantially hydrophilic fabric sandwiched between two said first layers of hydrophobic material such that said anti-bacterial binding is concentrated at the interface between said substantially hydrophobic first layers and said substantially hydrophilic second layer at the core of the absorbent material.

Typically said first layer will comprise 100% 5 decitex 60mm polyester fibre having a weight of between 60-lOOg per square metre and preferably 80g per square metre, said second layer comprises 100% MLO trilobal viscose fibre. The combination of said first and said second layers in a three layer structure i.e. said first layers providing outer hydrophobic layers and said second layer providing a core layer are secured together with in the order of 20-30 fibre pegs per square cm and a needle penetration of approximately lOmm in order to provide a consolidated final fabric in the order of 750-850mg per square metre.

The anti-bacterial binder as an impregnant comprises substantially water with approximately 3-5% solids, said solids being principally the polymer binder to secure the anti-bacterial solids within the absorbent material and those anti-bacterial agents, when solid. After impregnation the absorbent material has a weight of approximately 750850g per square metre and a gauge in the order of 7-15mm.

In accordance with the second embodiment of the present invention there is provided an absorbent material comprising a base absorbent fabric including an anti-bacterial binder washed into the base fabric in order to give up to 0.5% by weight concentration of liquid anti-bacterial liquid within the felt held by hydrophilic attract I' - 2 between said liquid anti-bacterial agent and said fibres ol the base absorption fabric.

Preferably the anti-bacterial agent is JMac solids in a liquid.

In accordance with the third embodiment of the present invention there is provided an absorbent material comprising a non-woven base absorbent fabric incorporating between 5 and 25% by weight of anti-bacterial fibres appropriately consolidated by fibre entanglement techniques e.g.

mechanically within the non-woven fabric.

Preferably, the anti-bacterial fibres are microsafe AM or Amicore.

An embodiment of the present invention will now be described by way of example only with reference to illustrations to provide representative constructions of absorbent material.

The most important aspect of ensuring that bacteria within an absorbent material does not produce noxious gases which can substantially reduce the acceptable life of an absorbent product used in incontinence or wound care is that the anti-bacterial agent is adequately dispersed throughout the absorbent material to be effective upon all bacteria present. It will be readily understood that if the antibacterial agent were to drift during manufacture or was only present in a limited proportion of the absorbent material the untreated areas of the absorbent material would rapidly produce the noxious gases and so make the whole product ineffective. This problem of adequate distribution is the principle difficulty with regard to incorporating antibacterial agents within an absorbent material. A secondary problem is of course, as indicated above, anchoring the anti-bacterial agent within the absorbent material in order to ensure in use the anti bacterial agent is simply not concentrated by the washing action of exudate or other liquid flowing within the absorbent material.

Anti-bacterial agents are available in many forms.

Thus, anti-bacterial agents are known in solid particulate form, as liquid agents and as fibres. The present invention addresses the problems of incorporating each one of these forms of anti-bacterial agent within principally a non-woven fabric. However, it will be understood that the techniques described are substantially applicable in both woven and knitted fabrics also.

An example incorporating solid particulate antibacterial agent within a non-woven fabric will now be described. The principle problem with solid particulate agents is obviously they are generally powders and thus susceptible to becoming dislodged within a non-woven fabric or the like. Thus, in accordance with the present invention most conveniently a multi-layered base absorbent fabric is provided comprising two first or outer layers of substantially hydrophobic non-woven material with a second or outer layer comprising substantially hydrophilic fibres.

Generally, the outer layers will comprise 100% by weight 5 decitex x 60mm polyester fibres tacked at approximately needled punch density or fibre tacks per square centimetre at a lOmm penetration.

Generally the second or inner layer will comprise 100% by weight xLO trilobal viscose fibres.

Two first or outer layers will be stacked with a second or inner layer located there between, such that there is a needle punch density of approximately 22 per square centimetre and a penetration of lOmm from both sides through the outer or first layers. The eventual non-woven base absorbent fabric will have a weight of approximately 780g per square metre. This fabric is then ready for impregnation with an anti-bacterial binder including both a solid particulate anti-bacterial agent, and a polymer binder.

The anti-bacterial binder is introduced to the fabric as described above as a solution. This solution is substantially water and includes both the particulate antibacterial agent, the polymer binder and a dispersant.

The anti-bacterial binder is impregnated into the fabric at a wet ratio of approximately 1.8 to 1 between the fabric and the binder in terms of weight. After impregnation the absorbent material including the antibacterial binder is dried at an elevated temperature and normally about 1200c. The final absorbent material will have a weight of approximately 800g per square metre and a It will be appreciated that as a substitute for a solid particulate anti-bacterial agent a liquid biocide such as actifresh T90-04 could be used.

Upon drying of the anti-bacterial binder i.e. the evaporation of the water content, it is found that the binder has mainly concentrated in the hydrophilic central core of the absorbent material such that the outer surfaces of the viscose have enhanced concentrations of antibacterial agent in comparison with the rest of the absorbent material. Thus, the two interfaces between the hydrophobic first or outer layers and the absorbent viscose hydrophilic core of the absorbed material have enhanced proportions of anti-bacterial agent. There is no detrimental effect upon absorbency as the anti-bacterial agent, particularly if a liquid, does not look or impair flow thorough the interstices in the non-woven layers, both outer or first hydrophobic layers or the inner hydrophilic layer. However, as the anti-bacterial agent is concentrated at the boundaries of the hydrophilic layer it will be appreciated that an advantageous affect occurs in that any noxious gases or bacteria producing such gases must pass through such zones of enhanced concentration and to be absorbed into the hydrophilic core.

The anti-bacterial agent within the anti-bacteria binder is carried into the absorbent fabric upon a wave of water impregnation. Thus, it will be appreciated there is good distribution of the anti-bacterial agent using this water carrier medium.

An alternative pseudo solid particulate anti-bacterial agent is that provided by JMac LP Concentrate. In an alternative example of the present invention a hydrophilic non-woven fabric is presented to an impregnant comprising 2.5% of JMac anti-bacterial agent such that the solids are readily distributed throughout the non-woven fabric. The preferred concentration in the impregnant is approximately 0.1% by weight JMac concentrate solids but impregnated at a ratio of 0.2 at pick up such that the weight percentage of JMac concentrate in the non-woven fabric is approximately 0.2% after drying.

Being a solid the JMac concentrate is washed into the hydrophilic non-woven fabric as a paste under hydraulic pressure during impregnation. The JMac tends to become distinct aggregates which are compressed into the interstices of the fabric to coat it. Upon drying the JMac becomes incorporated into the fibre structure or vice versa and so is securely anchored within the non-woven fabric.

Upon wetting with wound exudate or urine the JMac again swells but not under hydraulic pressure as during impregnation and thus generally is caged within the fibre interstices and so migration is inhibited. Thus, there is a resistance to concentration and pooling of the antibacterial JMac within the absorbent material and the effect upon bacteria within the absorbent material is maintained for a considerable period of time. However, it will be appreciated that the JMac may simply coat the fibres and a binder will be needed to resist washout from the fabric.

It will be appreciated that being a solid JMac the interstices of the fabric may become blocked whilst the JMac remains moist. Thus, there can be a diminution in the absorption process of the 'felt as compared to an untreated absorbent material comprising simply the felt on its own.

Once the JMac is dried the blocking effect of the interstices of the non-woven felt is reduced and absorbency at least in terms of initial rate are again improved towards that of the untreated non-woven fabric.

A final, third approach to securing an anti-bacterial agent within a non-woven absorbent material is to provide a percentage of anti-bacterial fibres within the non-woven fabric. It will however be appreciated that anti-bacterial fibres being speciality fibres tend to be expensive. Thus, to ensure adequate distribution of such anti-bacterial fibres within the non-woven it is necessary either to employ sophisticated blending techniques or to provide a significant proportion of anti-bacterial fibres within the non-woven fabric. Both extensive blending and high proportion anti-bacterial fibre non-woven fabrics add to expense.

Typically in the order of 10-20% of one fibre must be incorporated within the blend using conventional blending and carding equipment to ensure a proper distribution of that fibre throughout the non-woven batt prior to fibre entanglement techniques i.e. mechanical. If a lower proportion of the fibre is incorporated there cannot be a degree of certainty within the acceptable concentration variation within the batt to ensure an adequate distribution of anti-bacterial fibres for prevention of bacterial activity. However, the overriding factor is that the absorbent material incorporates sufficient anti-bacterial agent to kill bacteria whenever presented. Thus, over concentration is more acceptable than under concentration and trial and error must be utilised with regard to blending and carding to ensure the minimum level of anti-bacterial action in terms of anti-bacterial fibre presented per unit area of the absorbent material to ensure efficiency.

Examples of anti-bacterial fibre are Microsafe AM sold by Hoechst Celanese or Amicore sold by Courtaulds plc.

Practical absorbent materials incorporating these fibres have been achieved in which the anti-bacterial fibre content was as a proportion by weight in the order of 5-25%.

However, as indicated above, if sophisticated blending and carding techniques are employed it may be possible to substantially reduce the main anti-bacterial fibre content below this 5% limit.

Typically, the anti-bacterial fibres will be compatible with the base fibres used in the non-woven fabric in order that adequate fibre entanglement occurs to secure the antibacterial fibres within the core fibre matrix of the nonwoven fabric. If the anti-bacterial fibres were too short they would be inadequately secured within the structure and would fall out. If the anti-bacterial fibre were relatively coarse in comparison with the base matrix fibres of the nonwoven fabric it will be appreciated that in terms of available surface area for anti-bacterial activity there will be a diminution and possibly reduce anti-bacterial activity.

Claims

Claims:

1. An absorbent material comprising a first layer of substantially hydrophobic non-woven fabric and a second layer of substantially hydrophilic non-woven fabric, said first layer and said second layer being secured together by fibre pegs extending between said first layer and said second layer, said absorbent material being impregnated with an anti-bacteria binding including a binding polymer and solid or liquid anti-bacterial agents, said polymer binder securing said particulate anti-bacterial agent within said combined first non-woven fabric and said second non-woven fabric in a dispersed manner in accordance with wash impregnation.

2. An absorbent material according to Claim 1 wherein said second substantially hydrophilic fabric is sandwiched between two said first layers of hydrophobic material such that said anti-bacterial binding is concentrated at the interface between said substantially hydrophobic first layers and said substantially hydrophilic second layer at the core of the absorbent material.

3. An absorbent material according to Claim 2 wherein said first layer comprises 100% 5 decitex 60mm polyester fibre having a weight of between 60-lOOg per square metre and preferably 80g per square metre, and said second layer comprises 100% MLO trilobal viscose fibre.

4. An absorbent material according to Claim 3 wherein the combination of said first and said second layers in a three layer structure i.e. said first layers providing outer hydrophobic layers and said second layer providing a core layer, are secured together with in the order of 20-30 fibre pegs per square cm and a needle penetration of approximately lOmm in order to provide a consolidated final fabric in the order of 750-850mg per square metre.

5. An absorbent material according to Claim 4 wherein the anti-bacterial binder as an impregnant comprises substantially water with approximately 3-5% solids, said solids being principally the polymer binder to secure the anti-bacterial solids within the absorbent material and those anti-bacterial agents, when solid.

6. An absorbent material according to Claim 5 wherein after impregnation the absorbent material has a weight of approximately 750-850g per square metre and a gauge in the order of 7-15mm.

7. An absorbent material comprising a base absorbent fabric including an anti-bacterial binder washed into the base fabric in order to give up to 0.5% by weight concentration of liquid anti-bacterial liquid within the felt held by hydrophilic attraction between said liquid anti-bacterial agent and said fibres of the base absorption fabric.

8. An absorbent material according to Claim 7 wherein the anti-bacterial agent is JMac solids in a liquid.

9. An absorbent material comprising a non-woven base absorbent fabric incorporating between 5 and 25% by weight of anti-bacterial fibres appropriately consolidated by fibre entanglement techniques e.g. mechanically within the nonwoven fabric.

10. An absorbent material according to Claim 9 wherein the anti-bacterial fibres are microsafe AM or Amicore.