ABSORBENT MATERIAL AND METHOD OF MANUFACTURE THEREOF

Abstract: There is described absorbent material for use in absorbent products e.g. incontinence pads, and methods of making the material by needling. The material comprises at least three layers of non-woven fibre materials of which outermost layers (14, 16) at opposite sides of the material comprise hydrophobic fibres and at least one inner layer (18) between the outermost layers is an absorbent layer of hydrophilic fibres. The hydrophobic fibres are conveniently polyester and the hydrophilic fibres preferably trilobal viscose rayon which are significantly finer than the hydrophobic fibres. The absorbent material may be sandwiched between an impermeable backing layer and a permeable suitably knitted fabric, cover layer to provide an incontinence pad.

Description: ABSORBKHT MMΕRIMj AHD MBTHOD OF MANUFACTURE THEREOF This invention is concerned with an absorbent material suitable for use in absorbent products for example incontinence products and, more particularly, reusable incontinence products. There is described in EP-A-0 388062 a material referred to as a "graduated density felt", which material is suitable for use in an incontinence product and comprises a needled felt containing not less than 50% by weight polyester fibre, wherein surface regions of the felt are denser than a central region thereof, which remains substantially un-needled; that is to say, in the denser surface regions the fibres are reoriented from their original orientation by needling while the fibres in the less dense central region remain substantially in the original orientation. When in use as an incontinence product the less dense central region provides for fluid to be contained and/or absorbed therein, thereby enhancing the absorbency of the material. Although in the aforementioned EP-A- there is a proposal that 100% hydrophobic fibres be used in producing the material, in the various Examples in that specification the materials are composed of 80% by weight viscose and 20% polyester fibres. Viscose is of course hydrophilic and consequently tends to itself absorb fluid, whereas the polyester is essentially hydrophobic and does not absorb fluid. In the case of the 100% hydrophobic fibre base layer, therefore, the pool of fluid is contained within the structure of the material rather than absorbed into the individual fibres thereof. It will, however, be appreciated that incontinence products have also other requirements relating eg to comfort for the wearer, and in particular it is desirable that the fluid be removed from contact with the skin of the wearer and be prevented from returning to the surface and wetting it, when the product is subjected to pressure, in order to avoid the wearer suffering from rashes and other skin ailments due to contact with the fluid over perhaps extended periods. The reduction of "wet-back" also reduces odours and staining and, perhaps more importantly, gives the patient more confidence when using the product. In general, incontinence products which are commercially available have been of the disposable type, and thus not reusable, and a common approach to the prevention of wet-back and to achieving a "dry skin effect" has been to utilise so- called "superabsorbent" polymers which tend to bind the fluid to form a gel. Such a gelling process is of course substantially irrevocable and in any event washing would remove not only the gelled fluid but also the superabsorbent polymers themselves, so that with such a system a reusable incontinence product is unlikely to be achieved. Other approaches to achieving a "dry skin effect" have also been tried, usually involving the provision of a base layer of absorbent material and an additional layer which serves to enhance comfort by speeding up the spreading of the fluid throughout the base layer. In one such case, a towelling textile has been used as the additional layer which, by reason of its absorbency, tends to effect the spreading action satisfactorily, but at the same time itself tends to retain some of the liquid, especially when the product is placed under pressure, so that in this way a dry skin effect is nevertheless not achieved using such a material. It is one of the various objects of the present invention to provide an improved material for use in incontinence products, which material provides a comfortable dry skin effect to the wearer and which is reusable by washing. The invention provides, in one of its various aspects, an absorbent material for use in absorbent products comprising at least three layers of non-woven fibre materials, of which outermost layers at opposite sides of the material comprise hydrophobic fibres and at least one inner layer between the outermost layers is an absorbent layer. In a preferred absorbent material in accordance with the invention each absorbent inner layer consists of hydrophilic fibres disposed to draw liquid into the inner layer and retain it in the inner layer both by capillary action as well as by the inherent hydrophilic nature of the fibre. Preferably, the fibres of each absorbent inner layer or layers are viscose rayon, more preferably trilobal rayon fibres for example as available under the designation Courtaulds ML "0" trilobal fibres. In manufacturing a material in accordance with the invention by needling clusters of fibres may be caused to extend from the absorbent inner layer into the outermost layers and this may assist transfer of liquid into the inner layer. Preferably, the hydrophobic fibres are coarser than the fibres of each inner absorbent layer; the coarser fibres tend to have greater spacing between the fibres so that there is little tendency, it is believed, for capillary action to retain liquid in the layers of hydrophobic fibres. Conveniently, the hydrophobic fibres are polyester fibres or polypropylene. 1 Typically, the absorbent material has an area weight of about βOOgsm and is about 10-15mm in thickness. Conveniently, the absorbent material is a three layer material consisting of outermost layers of hydrophobic fibres and a single inner 5 absorbent layer. However, an absorbent material in accordance with the invention may be a multi-layer product consisting of outermost layers of hydrophobic fibres and a plurality of absorbent inner layers, preferably of hydrophilic fibres, separated by layers of hydrophobic fibres; conveniently the 10 separating layers are similar to the outermost layers but they may, if desired, be of different structure. In a preferred material in accordance with the invention the outermost layers preferably have an area weight of about 15150gsm and the absorbent inner layer of about 300gsm. Although the outermost layers are of hydrophobic fibres and the absorbent inner layer is of hydrophilic fibres in the preferred embodiments, it will be appreciated that the outmost 20 layers may comprise a small amount of hydrophilic fibres (other than those in any clusters drawn from the absorbent inner layer into the outermost layer), for example for bonding or other purposes, and likewise the absorbent inner layer or layers may include a small amount of hydrophobic fibre or 25 other materials, for example bactericidal agents. Although the preferred hydrophilic fibres are trilobal viscose rayon fibres, other hydrophilic fibres may be used in the manufacture of a material in accordance with the 30 invention, if desired. When a bactericidal agent is to be included in a material in accordance with the invention this may be introduced in any suitable manner. For example, the absorbent inner layer may 35 comprise a bactericidal fibre which may or may not be hydrophilic; this may be included in the absorbent inner layer at any convenient quantity, for example up to about 20% by weight, provided that satisfactory absorbency of the inner layer is maintained. Alternatively, the bactericidal agent may be included in material in accordance with the invention by bonding a suitable bactericide to the fibres using a bonding agent which may conveniently be, for example, styrene- butadiene rubber. Bactericidal fibres may include silver ions; for example a suitable fibre may be that supplied by Courtaulds under the trade name "Courtek M". In a material in accordance with the invention the outermost layers may comprise a quantity, for example up to about 5% by weight, of heat activated bonding agent which may be heat treated to lightly bond the hydrophobic fibres to one another. This may assist in keeping the "loft" or open nature of the outermost layers; a suitable heat activated bonding agent may be provided by heat-activated fibres eg bi-component fibres, for example copolyester core/sheath fibres supplied under the trade name Hoechst T252 or by a heat-activated powder adhesive material. In another aspect the invention may be considered to provide an absorbent pad comprising an absorbent layer of non- woven textile fibres sandwiched between a backing layer and a cover layer to assist in retaining the absorbent layer in place, the cover layer being permeable. Where the absorbent layer is a material in accordance with the invention both the cover layer and backing layer may each be a knitted or woven lightweight washable fabric of hydrophobic fibres, conveniently polyester fibres. The cover layer need only be sufficient to retain the absorbent layer in place and is sufficiently open to readily transmit moisture to the absorbent layer. The cover layer may in some circumstances comprise a heavier weight fabric of hydrophobic fibres, for example a raised open woven or knitted fabric. Preferably, the absorbent layer of a pad in accordance with the invention is a material in accordance with the invention. However, the absorbent layer may, if desired, comprise a non-woven absorbent material characterised by a denser surface region in which substantially all the fibres are oriented from their original orientation by needling, and by a less dense central region in which the fibres remain substantially in such original orientation, for example a material as described in our European Patent No 0388062B, made by a method as described in that patent. The backing layer of a pad in accordance with the invention may be provided in any suitable way; the backing layer may itself by an impermeable layer, or where the absorbent layer is an absorbent material in accordance with the invention the backing layer may in some circumstances be provided by a thin lightweight fabric identical with the cover layer (so that the pad is reversible). However, for most purposes an impermeable backing layer is preferred to ensure that there is no possibility of strike-through of liquid at the outer (back) face of the pad. The impermeable backing layer may comprise a woven cotton fabric coated with an impermeable layer, for example of synthetic rubber, suitably EPDM rubber or plastics material, for example a polyvinyl chloride material. The synthetic rubber or plastics coating is preferably on the inner surface of the backing layer, adjacent the absorbent layer. Where an impermeable backing layer is used, the absorbent layer preferably consists of an absorbent material in accordance with the invention or a material as described in our European Patent No 0388062B, however, other absorbent materials may be used in some circumstances. The cover and absorbent layers of a pad in accordance with the invention are preferably quilted together. The invention further provides in yet another of its aspects a method of making an absorbent material for use in absorbent products comprising forming at least three fibre webs, two of the webs comprising hydrophobic fibres and a third web comprising hydrophilic fibres, laying the webs on top of one another with said two webs comprising hydrophobic fibres sandwiching said third web, and subjecting the webs to a needling operation so as to join the webs to one another but such that the third webs are not unduly consolidated, thus to provide a material comprising at least three layers of non- woven fibre materials of which an inner layer is an absorbent layer. In carrying out one method in accordance with the invention the webs are subjected to a needling operation only after they have been laid on one another. In another method in accordance with the invention the three webs are subjected to needling operations before being laid on one another and thereafter subjected to a further needling operation so that all three webs are needled together. In carrying out a method in accordance with the invention where the webs are needled together, the needling operation carried out after the webs have been laid on one another is such as to cause clusters of fibres from the third web to extend into at least one of the two webs of hydrophilic fibres between which it is sandwiched. Preferably in carrying out a method in accordance with the invention the hydrophobic fibres are coarser that the hydrophilic fibres. Suitably the hydrophobic fibres may be of 5.0 decitex and the fibres of the third web may be about 2.6 decitex. Suitably the hydrophobic fibres are polyester fibres and the hydrophilic fibres are viscose rayon fibres preferably trilobal viscose rayon fibres. In a method in accordance with the invention it may in some circumstances be desirable to include a bactericidal agent in one or more of the webs; for example the webs may comprise up to 20% by weight of bactericidal fibres, suitably of the type mentioned previously. Alternatively, the bactericidal agent may be applied in carrying out a method in accordance with the invention by applying a dilute solution of a bonding agent, for example rubber, and bactericide to the material after the webs have been needled together. Conveniently, the solution may be applied by dipping the material into a dilute solution. In carrying out a method according to the invention, an amount of thermobonding fibre may be included in the hydrophobic fibre webs and in carrying out this method, the material may be heated after the webs have been needled together to activate the thermobonding fibre, thus to bond the hydrophobic fibres to one another; this is thought to militate against collapse of the webs, thus retaining the loft, or open nature, of the webs. in yet another aspect the invention may be considered to provide a process for making an absorbent pad, comprising making an absorbent material by a method in accordance with the invention, the process comprising sandwiching the absorbent material between a backing layer which is impermeable to liquids and a cover layer adapted to assist in retaining the absorbent material in place, the cover layer being permeable. Suitably the cover layer and the layer of absorbent material in the backing layer are quilted together. There now follows, to illustrate the new invention by way of example, descriptions of absorbent materials and their manufacture, set out hereinafter as Examples I-II and the processes of manufacture of pads embodying the invention set out hereinafter as Examples III and IV. Embodiments of materials, products and methods in accordance with the present invention are described by way of example only with reference to the accompanying drawings in which:- Figure 1 is a diagrammatic view showing a first method of manufacturing an absorbent material embodying the invention; Figure 2 is a diagrammatic view in section of a material embodying the invention; Figure 3 is a schematic cross-section of an incontinence pad; and, Figure 4 is a plan view of said paid illustrated in Figure 3 Example I In carrying out a first method of manufacturing absorbent material in accordance with the invention, use is made of well known techniques for forming non-woven fibre sheet materials, involving carding and needling operations. In carrying out the first illustrative method, three fibre webs are formed by carding techniques, although any known techniques for forming non-woven webs from textile fibres may be utilised. With a reference to Figure 1, a first web of polyester fibres is formed by a card A and laid by known cross-lapping techniques onto a conveyor 10, the conveyor 10 moving in a direction indicated by an arrow to a needling apparatus 12 of generally known construction. The needling apparatus comprises a tacker board and two needling beds each having two needle boards. The needling apparatus used in this Example is particularised below but it will be appreciated by the skilled person that the needling process may be adjusted according to the properties required. The present apparatus has a tacker board in which all the needles are 40 gauge number R333 G1909. On the first bed of the needling apparatus, board A has 40 rows of needles and in rows 1-20 and 31-40, 40 gauge needles designation 1909 are used, whilst in rows 21-30, 38 gauge, designation C333 needles are used. In board B also having 40 rows, all of the rows are populated with 40 gauge F222 needles. On the second bed of the needle loom, board C is populated with needles arranged as in Board A and Board D with needles as in Board B. In the operation of the needling apparatus the penetration of the tacker needles is about 4mm, the needles in bed 1 have a penetration of about 8mm and those in bed 2 have a penetration of about 10mm. All needling is carried out from above the bat. The output speed from the needling apparatus is about 1.5m/minute. The illustrative material leaving the needling apparatus 12 comprises three layers, the two outermost layers 14,16 comprise hydrophobic fibres and the inner layer 18 provides an absorbent layer. The web laid by the card A provides a layer 16, that laid 1 by the card B provides the layer 18 and that laid by the Card C provides the layer 14. The material produced in this way is an absorbent 5 material illustrative of the invention in one of its aspects. The absorbent material has an area weight of about 600gsm and the total thickness of the absorbent material is approximately 1cm. The layers 14,16 are very slightly thicker than the layer 18, both layers 14,16 being 10 approximately 3.5mm in thickness and the layer 18 being approximately 3mm in thickness. In carrying out the first illustrative method, the layers 14,16 both have a weight of about 150gsm and are formed from 155.0 decitex polyester textile fibres supplied by Hoechst. The inner absorbent layer 18 has an area weight of about 300gsm and is formed of Courtaulds ML "0" trilobal viscose rayon fibres which are finer than the fibres of the outer layer, being of about 2.6 decitex. In tests of the first 20 illustrative material, the material was found to absorb liquid readily and to transmit it into the absorbent inner layer 18. The surface of the outermost layers had an apparently dry surface and the liquid was retained substantially in the absorbent inner layer. When the fabric was placed under a 25 load (as would arise for example, in use of a pad constructed of the absorbent material in bedding) there was a relatively small amount of liquid wet-back to the surface of the outermost layers. Furthermore, the wicking of the absorbent inner layer ensured the absorbed liquid was removed from the 0 region at which it was drawn into the absorbent layer and spread throughout the absorbent layer thereby ensuring that a large quantity of liquid can be absorbed and retained within the inner absorbent layer even if most of it is introduced into the absorbent layer at about the same region. 35 It was found that the material could be washed a number of times (when incorporated in a pad) removing most or all of the absorbed liquid and other material so that the illustrative absorbent material could be reused a large number of times. Example II In carrying out a second illustrative method of manufacturing absorbent material, three non-woven fibre fabrics are made by carding and needling using for two of the layers the polyester fibres referred in Example I and for the third layer the trilobal viscose rayon fibre used in Example I. The three non-woven needled fabrics are fed continuously, laid on top of the other with the viscose rayon fabrics sandwiched between the two polyester fabrics and the whole subjected, to a further needling operation to form the second illustrative absorbent material. in the manufacture of the second illustrative absorbent material, the needling operation by which the three non-woven fabric layers are needled together is carried out using needles penetrating from both above the layers fabrics and below the fabrics to give sufficient security. The needles used were similar to those used in the first illustrative method, so that the overall needle punch density of the second illustrative material was about the same as the first illustrative material. Furthermore, the amount of fibres used in producing each of the three non-woven fabrics is chosen such that the second illustrative material has an area weight of about 600gsm (similar to the first illustrative material) and so that the area weight of the outermost layers are each about 150gsm and that of the absorbent inner layer about 300gsm, as in the first illustrative material. Furthermore, the thickness of the three layers 14,16, 18 are also similar to those in the first illustrative material. The absorbency and wet-back properties of the second illustrative material are generally similar to those of the first illustrative material and the second illustrative material exhibits good wicking. However, there appears to be a tendency for the wicking in the machine direction of the second illustrative material to be somewhat greater than in the cross machine direction. Thus, it is thought that the second illustrative material may be more suitable for use in incontinence pads which are long and relatively narrow: such incontinence pads are preferably made to be worn under garments with the machine direction of the absorbent material extending in the lengthwise direction of the pads. On the other hand, the more uniform wicking action of the first illustrative material may render it more suitable for use as an incontinence pad to be used in bedding. In the illustrative absorbent materials, fibres from the absorbent inner layer are carried by the needling operation into the outermost layers thus to provide small clusters of fibres throughout the outermost layers which tend to facilitate transmission of liquid into the absorbent inner layer. Whereas the illustrative materials are made by needle punching techniques, in some circumstances it may be possible to use air jets or water jets ie hydro entanglement to sufficiently entangle the fibres of the various layers. Example III An absorbent pad for use as an incontinence pad is described in this example. The first illustrative absorbent pad comprises an absorbent layer of non-woven textile fibres, namely the first illustrative absorbent material described in Example I, sandwiched between a backing layer which is impermeable, namely a woven cotton cloth having on one surface an impermeable polyvinylchloride film with the polyvinylchloride film in contact with the absorbent layer, and on the other side a cover layer. The cover layer is, in use, in contact with the user. The cover layer is preferably a lightweight textile fabric of somewhat open construction which allows ready penetration of liquid to the absorbent material but which is comfortable when in contact with the skin. Suitably, the cover layer is knitted or woven from hydrophobic fibres, preferably polyester fibres. The absorbent material and cover layer are quilted together using known quilting techniques and then the backing layer secured to the quilted cover and absorbent layers a round the periphery eg by sewing to form a first illustrative absorbent pad. Example IV A second absorbent pad is described to further illustrate the invention in this example. The second illustrative pad likewise comprises an absorbent layer of non-woven textiles fibres sandwiched between an impermeable layer and a permeable cover layer. In this instance, the absorbent layer is a material substantially as described in European Patent No 0388062B which is supplied under the designation "Texon PL 441 FP", by the applicant company. The backing layer is a woven cotton fabric (comprising 42% by weight of the backing layer) and a synthetic rubber, namely EPDM rubber, barrier layer providing about 58% by weight of the backing layer. The backing layer is positioned with the synthetic rubber coating in contact with the absorbent layer. Finally, a cover layer is provided: this layer is of heavier weight than the cover layer of Example III and is a polyester fabric, raised on the side of the cover layer opposite the absorbent layer, manufactured by Rokona under the reference 108.260. The cover layer and absorbent layer are quilted together and the backing layer is attached to the absorbent layer and the cover layer by stitching around the periphery of the absorbent pad only. The completed pad has a weight of about 600 gsm and has been found to be washable through a number of washing cycles to remove liquid and soiling, so that the second illustrative pad can be reused on a number of occasions. Referring to Figures 3 and 4. An upper permeable layer 1 is secured to an absorbent needle felt layer 2 in the illustrated embodiment using quilt stitchers 3. However, it will be appreciated that other securing techniques could be used or in some circumstances the upper layer 1 and the absorber 2 could be substantially free and not secured together. In any event the fluid integrity within the incontinence pad is achieved by the backer layer 4. The backer layer 4 includes an impermeable surface coating 5 supported on a textile material such as cotton to give the advantage of non-slip location upon bed linen. The backer layer 4 is rolled over or provides an interlocking edge about the periphery of the upper layer 1 in order to inhibit leakage of incontinent fluid. It will be appreciated that the stitches 3 penetrate completely through the absorbent layer 2 or as illustrated merely penetrate a proportion of the width of the layer 2. Fig. 4 shows a typical stitch pattern to ensure substantial top layer 1 and absorbent layer 3 location. However other patterns could be used. The absorbent layer 3 is a needle felt having an expanded structure and so voids within its volume to accommodate incontinent fluid. Furthermore, there is adequate structural integrity within such a needle felt to limit compression of the absorbent layer 3 through patient weight and so ameliorate any squeezing effect and so strike-back of incontinence fluid back from the absorbent layer 3 and into contact with the patient. However, as an additional precaution a one-way or stay dry layer which allows fluid only to pass downwards into the absorbent layer 3 may be added between or above the upper layer 1 although not shown in the Figures. Furthermore, a stay dry or one-way facility could be incorporated in the upper layer 1. Due to the stability of the pad both in terms of location within the patient's bed and the prevention of wrinkling between the upper layer 1 and absorbent layer 2 by quilt stitches 3 it is possible to manufacture large, i.e. Im2, incontinence pads which can be placed above cotton sheets within a patient's bed and so reduce friction and so bed sores along with pad location problems. Furthermore, it may be possible to eliminate the need for a "back stop" rubber sheet beneath the cotton linen. A suitable absorbent layer material is described in European Patent No. 0 388 062 (graduated density felt). The material comprises layers of variously needled web such that the outer areas of the layer have greater entanglement and therefore density as compared to more central regions and so the layer has significant void space to accommodate liquid. A further alternative for the absorbent layer 2 is described above, in which a multi-layered material is described having outer hydrophobic fibre felt layers and an inner absorbent layer which may be made of hydrophilic fibres, the whole material being needled to provide a substantially stable structure. These expanded structure felts are formed by in effect entangling fibres to create a web. This entanglement is achieved using needles which penetrate the web on a down stroke and are barbed or hooked in some manner in order to grab fibres on a return stroke and thus entangle strands of fibre between respective web layers. Furthermore, this needling operation tends to consolidate the web from a voluminous highly open structure into a condensed felt although still having voids. Thus grading of felts is typically done using density figures. It will be appreciated that through selective needling it is possible to create structural differences through the felt layer and in the present case as described in the European Patent above the outer areas of the felt are needled to a greater extent than the central area and thus an open structure is provided within the felt having voids to accommodate incontinence fluid whilst having a structural surface which can take a stitch or other bonding technique. The alternative, as described above is to combine or laminate several pre-needled webs of felt having different properties through such needling process or their fibre composition together to create a desired absorption quality. Again with such a laminated approach it is possible to limit needling to specific levels within the material and so determine properties. Typically the absorption layer may be made of polyester fibres or viscose rayon fibres or other suitable hydrophilic or hydrophobic fibres dependent on the desired performance. However, as indicated previously, one of the principal advantages of the present pad is that the absorption layer has voids in which incontinent liquid can be accommodated whilst the layer has sufficient structural integrity to ensure there is no or only limited compression or squeezing effect upon the absorption layer when a patient lies upon it. The main advantage of the present pad is that it is re¬ usable, i.e. the pad can be washed in order that the incontinent fluid is removed through the washing process and the pad dried in an appropriate manner. However it is also necessary, and as will be appreciated, to sanitize the pad before further use. This sanitizing stage in the laundering process is most conveniently conducted through a bleach soak at elevated temperatures. Again choice of fibre for the absorbent and for that matter other layers of the pad is dictated to a certain extent by the necessary sanitization steps. It is the combination of upper layer 1, absorbent layer 2 and backer 4 which determines a further desirable feature of re-usable incontinence pads in that they should remain substantially flat after the laundry stage. It will be appreciated that a pad which tended to curl or distort in the relatively hostile environments particularly that of sanitization presented in the laundering process would not be adequate and acceptable due to the resultant patient discomfort and use problems. In the present invention it has been found as outlined above that an upper layer formed of 100% polyester roughened on the side turned towards the patient (i.e. Rδkona reference 108.260 colour 7050-Y-White) in combination with an absorbent layer formed of TEXON PL441 FP and a backer comprising a cotton sheet bleached and with a synthetic rubber EPDM as an inside impermeable barrier layer within the pad produces an assembly which does not curl during expected laundry processes. The absorbent TEXON PL441 FP graded felt may have a mixture of polyester and viscose fibres in the ranges 55 to 65% weight polyester to 35 to 45% viscose fibres but normally notionally 60% polyester fibre (decitex around 5 and 40mm lengths) and 40% viscose fibres (1.7 decitex and 51mm length) . Furthermore the principle requirement of the impermeable layer on the backer 4 is that it should have environmental resilience thus the thickness and type of coating used will be dependent upon laundry processes. It will be appreciated that in addition to providing an incontinence pad the present invention could also be used as a drip or spill mat for use in other environments such as where oil or other fluid spillage would cause environmental damage or aesthetic distress.

Claims: Claims : 1. An absorbent material for use in absorbent products comprising at least three layers of non-woven fibre materials, of which outermost layers at opposite sides of the material comprise hydrophobic fibres and at least one inner layer between the outermost layers is an absorbent layer. 2. A material according to Claim 1 wherein the inner absorbent layer or layers consists of hydrophilic fibres disposed to draw liquid into the inner layer and retain it in the inner layer or layers both by capillary action as well as by the inherent hydrophilic nature of the fibre. 3. A material according to Claim 1 wherein the outermost layers comprise up to 5% by weight heat-activated bicomponent fibres. 4. An absorbent pad comprising an upper permeable layer secured to an absorbent needled felt layer, the absorbent layer having an expanded structure to accommodate fluids whilst maintaining structural integrity, the pad having a backer layer comprising a textile support matrix upon which an impermeable barrier film is adhered, the backer layer being secured about the periphery of the upper layer to inhibit liquid passage through said edge. 5. A pad as claimed in Claim 1 wherein the absorbent layer comprises a material as claimed in any of Claims 1 to 4. 6. A pad as claimed in Claims 4 or 5 wherein the absorbent layer is formed from a combination of polyester and viscose fibres in the proportion of between 55 and 65% polyester fibre and 35 to 45% viscose fibre. 7. A method of making a material for use in absorbent products comprising forming at least three fibre webs, two of the webs comprising hydrophobic fibres and a third web comprising hydrophilic fibres, laying the webs on top of one another with said two webs comprising hydrophobic fibres sandwiching said third web, and subjecting the webs to a needling operation so as to join the webs to one another but such that the webs are not unduly consolidated, thus to provide a material comprising at least three layers of non- woven fibre materials of which an inner layer is an absorbent layer. 8. A method according to Claim 7 wherein the webs are subjected to a needling operation only after they have been laid on one another. 9. A method according to Claim 7 wherein the three webs are subjected to needling operations before being laid on one another and are subjected to a further needling operation after they have been laid on one another. 10. A method according to Claim 7 wherein the needling operation carried out after the webs have been laid on one another is such as to cause clusters of fibres from the third web to extend from the third web into at least one of the two webs of hydrophobic fibres between which it is sandwiched.

Inventors: BRASSINGTON NIGEL JOHN, JOHNSON SUSAN GWYNNETH, STREULI HEINZ, BRASSINGTON, NIGEL, JOHN, JOHNSON, SUSAN, GWYNNETH, STREULI, HEINZ
Applicants: BRASSINGTON NIGEL JOHN, BRITISH UNITED SHOE MACHINERY, JOHNSON SUSAN GWYNNETH, STREULI HEINZ, BRASSINGTON, NIGEL, JOHN, BRITISH UNITED SHOE MACHINERY LIMITED, JOHNSON, SUSAN, GWYNNETH, STREULI, HEINZ
Application year: 1995
Main classification: D04H13
IPC codes: D04H13