BREATHABLE PERSPIRATION PADS

Abstract: The present invention relates to a breathable perspiration pad (A, B, C, E1-E3), such as underarm, wrist, head perspiration pads, collar inserts, and shoe inserts having a breathable backsheet to provide improved performance of the perspiration pad.

Description: BREATHABLE PERSPIRATION PADS Field of the Invention The present invention relates to improved absorptive articles for the absorption of perspiration such as underarm perspiration pads, collar inserts, shoe inserts and the like. The present invention both hinders the generation of perspiration and its associated malodour and effectively absorbs any perspiration produced, thereby preventing its visible and olfactory detection. Background of the Invention The generation of perspiration by the human body is a well known bodily function which is due mainly to climatic changes and physical exertion. In this manner the body provides a natural cooling system. Although the degree of perspiration generated varies from person to person, under certain circumstances the human body will always perspire. However, whilst perspiration is a natural bodily function, it is also often associated with a lack of bodily hygiene and cleanliness. In addition, the majority of people also experience discomfort whilst perspiring. In addition, perspiration is typically also associated with the staining of clothing, which is unsightly. This problem is exacerbated by certain types of design of clothing such as tight fitting clothing and the use of synthetic materials in clothing manufacture. Unfortunately, this type of perspiration related staining of clothing is difficult to remove and often remains visible on clothing after washing or dry cleaning. Furthermore, another problem related to the generation of perspiration is the associated and distinctive unpleasant odour. Malodorous compounds typically present, may originate from a number of sources. Firstly, the actual components of the fluid discharge i.e., perspiration may contain malodorous compounds. Secondly, malodorous compounds are also generated as a result of the degradation of the components of perspiration. The presence and particularly the detection of perspiration is the cause of considerable embarrassment to many people, especially those people suffering from a tendency to perspire heavily. Hence, it is highly desirable to prevent the detection of human perspiration. One means of addressing this problem is the use of antiperspirants or deodorisers which are applied to the skin in the form of aerosols, roll-ons, sticks and gels. For example EPO 710 812 discloses a method of preventing underarm malodour associated with human perspiration by the use of a macroporous crosslinked copolymer containing acrylate or methacrylate units. The polymer entraps the fatty acid components of perspiration and thereby denies access to the acid by skin bacteria and consequently reduces body malodour. However, for many people antiperspirants and deodorants are not particularly effective. Furthermore, there is a desire of many consumers to avoid the use of such compounds on the skin as many of these compounds are considered as skin irritants and also as it is not considered to thereby hinder the body's natural reaction to perspire. In addition, such products also do not address the problem of staining of clothing. In fact, many antiperspirant products cause additional staining of clothing and contribute to the degradation of the clothing itself. An alternative means of addressing the problem of the generation of perspiration is to use absorbent articles. Such articles have been long recognized as a means of addressing this problem and there are a number of reference to articles designed specifically to absorb perspiration, particularly designed for utilisation on areas of the body susceptible to perspiration such as the armpit, neck or soles of the feet. For example the perspiration pads as described in US 467 898, DE 31 04 047, DE 2841 365 and DE 39 09 218. The primary focus of such perspiration pads is to absorb fluids. This is typically achieved by providing a pad having an absorbent material. However, the utilization of only an absorbent material for perspiration pads, does not ensure that the absorbed fluids are retained in the pad. Consequently perspiration pads are typically provided in addition, with a liquid impervious backing material, or backsheet. In this manner the pad absorbs the excreted fluids and prevents the staining of clothing. However, another problem arises is that these products in general tend to be uncomfortable to wear. In particular in order to function appropriately the pads are required to be maintained in close and tight contact with the skin. This is usually achieved by the use of fastening means such as adhesives. Thus, the use of the perspiration pads themselves may cause the user of the product to perspire more heavily. Furthermore, the amount of associated malodour resulting from the perspiration is also increased. Hence, there still exists a need to provide alternative and improved perspiration pads, particularly perspiration pads which provide improved wearer comfort and which reduce the detection of malodorous compounds. It has now been surprisingly found that the above needs can be met by perspiration pads having a breathable backsheet. The incorporation of breathable backsheets in absorbent articles such as sanitary napkins for improved wearer comfort has been described in the art such as for example in GB 2 184 389, US 3 881 489, EPO 203 821 and US 4 059 114. However, none of these prior art documents recognize the benefits of the provision of a breathable perspiration pad by the utilization of a breathable backsheet. It is believed that the performance benefit of a breathable perspiration pad is due to a number of factors. Firstly, the reduction in the hot, humid and occlusive environment between the vicinity of the skin of the wearer and the wearer facing surface of the perspiration pad itself also reduces the tendency of the wearer of the product to perspire. Hence the wearer will feel more comfortable. Consequently, the amount of associated perspiration related odour will be reduced. Thus, the breathability of the pad actually reduces the amount of odour generated within the perspiration pad. Secondly, the breathability of the absorbent pad reduces the hot humid and anaerobic environment between the skin of the wearer and the surface of the perspiration pad. This hinders the growth of microorganisms, which are also known to be responsible for the generation of odorous compounds. Thus, the amount of odours associated with the presence of microorganisms is reduced by the perspiration pads of the present invention. In addition, due to the breathable nature of the pad, the malodorous compounds contained therein may, similar to water vapour and air, be more readily exchanged with the environment. Hence, malodorous compounds are able to escape from the article and are dissipated into the surroundings. More importantly, the breathability of the pad also allows the precursors compounds of malodorous compounds present in the article to escape from the perspiration pad before degradation commences and hence before malodour formation takes place. A further advantage of the perspiration pads of the present invention is that the need to use antiperspiration products is eliminated thereby allowing the body to perspire naturally, without the possibility of the generation of stains on clothing or detection of malodours. Summary of the Invention The present invention relates to a disposable absorbent perspiration pad, comprising an absorbent core and a backsheet, wherein said backsheet is breathable. The breathability of the perspiration pad provides a pad of improved comfort and unexpectedly also provides odour control performance. Detailed Description of the Invention The present invention relates to disposable breathable perspiration pads, which may be used in conjunction with articles of clothing and undergarments, or as a separate article, positioned where perspiration or excessive perspiration occurs. Examples of perspiration pads include underarm-, wrist- and head perspiration pads, collar inserts, shoe inserts, hat bands and breast pads. Typically such products comprise an absorbent core and a backsheet. According to the present invention the breathability of the perspiration pad is provided by the presence of a breathable backsheet which thereby allows the circulation of water vapour and preferably both water vapour and air through it. Backsheet According to the present invention, the perspiration pads comprise as an essential component a breathable backsheet. The primary role of the breathable backsheet is to prevent the extrudes absorbed and contained in the pad from wetting clothing that contact the absorbent pad such as jackets, shirts, blouses, dresses, pants and undergarments. In order to achieve this the backsheet typically extends across the whole of the absorbent structure and may extend into and form part of or all sideflaps, side wrapping elements or wings. In addition however, the breathable backsheet permits the transfer of water vapour and preferably both water vapour and air through it and thus allows the circulation of air into and out of the backsheet and the perspiration pad itself. Suitable breathable backsheets for use herein include all breathable backsheets known in the art. In principle there are two types of breathable backsheets, single layer breathable backsheets which are breathable and impervious to liquids and backsheets having at least two layers, which in combination provide both breathability and liquid imperviousness. Suitable single layer breathable backsheets for use herein include those described for example in GB A 2184 389, GB A 2184 390, GB A 2184 391 , US 4 591 523, US 3 989 867, US 3 156 242 and European Patent Application number 95120653.1. Suitable dual or multi layer breathable backsheets for use herein include those exemplified in US 3 881 489, US 4 341 216, US 4 713 068, US 4 818600, EPO 203 821, EPO 710 471, EPO 710 472, European Patent Application numbers 95120647.3, 95120652.3, 95120653.1 and 96830097.0. Particularly preferred are backsheets meeting the requirements as defined in European Patent Application number 96830343.8 and more preferably wherein the perspiration pads also meets the requirements as described therein. According to the present invention the breathable backsheet comprises at least one, preferably at least two water vapour permeable layers. Suitable water vapour permeable layers include 2 dimensional, planar micro and macro-porous films, monolithic films, macroscopically expanded films and formed apertured films. According to the present invention the apertures in said layer may be of any configuration, but are preferably spherical or oblong. The apertures may also be of varying dimensions. In a preferred embodiment the apertures are preferably evenly distributed across the entire surface of the layer, however layers having only certain regions of the surface having apertures is also envisioned. 2 dimensional planar films as used herein have apertures having an average diameter of from 5 micrometers to 200 micrometers. Typically, 2- dimensional planar micro porous films suitable for use herein have apertures having average diameters of from 150 micrometers to 5 micrometers, preferably from 120 micrometers to 10 micrometers, most preferably from 90 micrometers to 15 micrometers. Typical 2 dimensional planar macroporous films have apertures having average diameters of from 200 micrometers to 90 micrometers. Macroscopically expanded films and formed apertured films suitable for use herein typically have apertures having diameters from 100 micrometers to 500 micrometers. Embodiments according to the present invention wherein the backsheet comprises a macroscopically expanded film or an apertured formed film, the backsheet will typically have an open area of more than 5%, preferably from 10% to 35% of the total backsheet surface area. Suitable 2 dimensional planar layers of the backsheet may be made of any material known in the art, but are preferably manufactured from commonly available polymeric materials. Suitable materials are for example GORE-TEX (TM) or Sympatex (TM) type materials well known in the art for their application in so-called breathable clothing. Other suitable materials include XMP-1001 of Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, USA. As used herein the term 2 dimensional planar layer refers to layers having a depth of less than 1mm, preferably less than 0.5mm, wherein the apertures have an average uniform diameter along their length and which do not protrude out of the plane of the layer. The apertured materials for use as a backsheet in the present invention may be produced using any of the methods known in the art such as described in EPO 293 482 and the references therein. In addition, the dimensions of the apertures produced by this method may be increased by applying a force across the plane of the backsheet layer (i.e. stretching the layer). Suitable apertured formed films include films which have discrete apertures which extend beyond the horizontal plane of the garment facing surface of the layer towards the core thereby forming protuberances. The protuberances have an orifice located at their terminating ends. Preferably said protuberances are of a funnel shape, similar to those described in US 3, 929,135. The apertures located within the plane and the orifices located at the terminating end of protuberance themselves maybe circular or non circular, provided the cross sectional dimension or area of the orifice at the termination of the protuberance is smaller than the cross sectional dimension or area of the aperture located within the garment facing surface of the layer. Preferably said apertured preformed films are uni directional such that they have at least substantially, if not complete one directional fluid transport towards the core. Suitable macroscopically expanded films for use herein include films as described in for example in US 637 819 and US 4 591 523. Suitable macroscopically expanded films for use herein include films as described in for example US 4 637 819 and US 4 591 523. Suitable monolithic films include HytreL, such as Hytrel HTR-8206 and Hytrel G 3548, available from DuPont Corporation, USA, and other such materials as described in Index 93 Congress, Session 7A "Adding value to Nonwovens", J-C. Cardinal and Y. Trouilhet, DuPont de Nemours International S.A, Switzerland. According to the present invention the backsheet may comprise in addition to said water vapour permeable layer additional backsheet layers. Said additional layers may be located on either side of said water vapour permeable layer of the backsheet. The additional layers may be of any material, such as fibrous layers such as wovens, nonwovens or additional water vapour permeable apertured films. According to the present invention the perspiration pads may further comprise an absorbent core. The absorbent material or core which can be fluffy fibrous absorbent core comprising hydrogel particles if desired, laminated tissues with or without particulate materials including hydrogel particles. The absorbent core fibres can be any on those known in the art including cellulose fibres or polymeric fibres rendered absorbent or even non absorbent matrix fibres. Also tissues of sufficient basis weight and absorbency can be used in the absorbent core according to the present invention. According to the present invention the perspiration pads of the present invention may further comprise a topsheet. Suitable topsheets may comprise a single layer or a multiplicity of layers. In a preferred embodiment the topsheet comprises a first layer which provides the user facing surface of the topsheet and a second layer between the first layer and the absorbent structure/core. The topsheet provides a layer through which the liquids to be absorbed penetrate to the absorbent material. The absorbent core is thus positioned intermediate the backsheet and the topsheet. The topsheet as a whole and hence each layer individually needs to be compliant, soft feeling, and non-irritating to the wearer's skin. It also can have elastic characteristics allowing it to be stretched in one or two directions. Typically, the topsheet extends across the whole of the absorbent structure and can extend into and form part of or all of the preferred sideflaps, side wrapping elements or wings. According to the present invention the topsheet may be formed from any of the materials available for this purpose and known in the art, such as non woven fabrics, films or combinations of both. In a preferred embodiment of the present invention at least one of the layers of the topsheet comprises a hydrophobic, liquid permeable apertured polymeric film. Preferably, the upper layer is provided by a film material having apertures which are provided to facilitate liquid transport from the wearer facing surface towards the absorbent structure, as detailed for example in US 3 929 135, US 4 151 240, US 4 319 868, US 4 324 426, US 4 343 314 and US 4 591 523. A suitable commercially available topsheet for use herein is BPC 45105 CPM available from BP Chemicals. According to the present invention the perspiration pad is constructed by joining the various elements such as topsheet, backsheet and absorbent core by any means well known in the art. For example the backsheet and/or topsheet may be joined to the absorbent core or to each other by a continuous layer of adhesive, a patterned layer of adhesive, or an array of separate lines, spirals or spots of adhesive. Alternatively, the elements may be joined by heat bonds, pressure bonds, ultra sonic bonds, dynamic mechanical bonds or any other suitable joining means known in the art and any combination thereof. Preferably the breathable backsheet is bonded to other elements of the perspiration pads so as to minimise and preferably eliminate any reduction in the vapour permeability of the backsheet. In addition to the elements previously described, the perspiration pad may also comprise in addition odour control actives. Suitable odour control actives include antiperspirants and deodorants. In a preferred embodiment of the present invention, wherein the perspiration pad is used in conjunction with articles of clothing or undergarments, the pad is also provided with a garment fastening means which allows attachment of the pad to a garment during use. For example, the garment fastening means may comprise a mechanical fastener such as hook and loop fasteners such as marketed under the tradename VELCRO, snaps or holders. Alternatively, the pad may be fastened to the garment by means of garment fastening adhesive on the backsheet. The garment fastening adhesive provides a means for securing the pad to the garment and preferably a means for securing the pad when soiled, to the fold and wrap package for convenient disposal. Typically, at least a portion of the garment facing surface of the backsheet is coated with adhesive to form the garment fastening adhesive. Any adhesive or glue used in the art for such purposes can be used for the fastening adhesive herein. Pressure sensitive adhesives are most preferred. Suitable adhesives include Century A-305-IV manufactured by the Century Adhesives Corporation of Columbus, Ohio, and Instant LOK 34-2823 manufactured by the National Starch and Chemical Company of Bridgewater, New Jersey, 3 Sigma 3153 manufactured by 3 Sigma, LA203 available from Savare SpA, Italy and Fuller H-2238ZP manufactured by the H.B. Fuller Co. The garment fastening adhesive is typically applied to the backsheet by slot coating. In order to reduce the effect of the adhesive on the breathability of the backsheet and perspiration pad as a whole, the adhesive is preferably applied such that at least 60%, preferably at least 80%, most preferably at least 90% of the garment facing surface of the backsheet is adhesive free. The required adhesiveness can still however be provided even when using reduced surface coverage by using particular distribution, such as thinner strips, discontinuous strips, intermittant dots, random spiral patterns or mixtures thereof. The garment fastening adhesive is typically covered with a removable release paper or film in order to prevent the adhesive from drying out or adhering to another surface other than the garment prior to use. Any commercially available release paper or film may be used. Suitable examples include BL 40G EF MGA SILOX C4R10, BL 30MG-A SILOX El/O and BL 30 MG-A SILOX 4 P/O available from Akrosil Corporation. In an alternative embodiment of the present invention the perspiration pad may be provided with a wearer fastening means whereby the pad is provided with means to be attached to the body of the wearer as opposed to the garment of the wearer. Typically such wearer fastening adhesives are positioned on at least a portion of the wearer facing surface of the topsheet, if present, or the absorbent core. Alternatively, particularly for applications such as wrist- and headbands the wearer fastening means may be provided by elastising at least part of the pad. According to the present invention the perspiration pad may find utility as underarm-, wrist- and (fore) head perspiration pads, collar inserts, shoe inserts, hat bands and breast pads. The perspiration pad may also find utility in clothing in particular sports clothing. The present invention finds particular susceptibility as underarm perspiration pads. In addition to the components described herein above, the perspiration pad may also comprise all those features and parts which are typical for products in the context of their intended use such as garment fastening means, release paper, wrapping elements and the like. Typically the dimension, flexibility, size and shape of the pad will depend on the intended location of the pad on the body and can be easily adapted by the skilled man dependent on the end use. For example underarm prosperation pads are typically provided in a circular or oval shape or in a waning circular or waning oval shape as illustrated in figures 1 and 2 and are usually symmetrical. Similarly the perspiration pads may be provided in a range of colours in order to more effectively camouflage the use of the pads, particularly when utilised under clothing. Figures 1 and 2 illustrate a breathable underarm perspiration pad according to the present invention. The pad comprises two symmetrical areas A and B, that are attached to one another at the curved area indicated as C, with a strip of adhesive D. In addition the pad also comprises three additional garment adhesives strips E1 , E2 and E3. The adhesives strips are typically covered with a release paper (not shown).

Claims: WHAT IS CLAIMED IS: 1. A perspiration pad comprising a backsheet and an absorbent core, characterized in that said backsheet is breathable. 2. A perspiration pad according to claim 1 , wherein said perspiration pad further comprises an odour control system. 3. A perspiration pad according to any one of the preceding claims, wherein said breathable backsheet comprises at least one layer selected from an apertured formed polymeric film, a 2-dimensional planar apertured film or a monolithic film. 4. A perspiration pad according to claim 3, wherein said layer is a 2 dimensional planar apertured layer, wherein said apertures have an average diameter of from 150 micrometers to 5 micrometers. 5. A perspiration pad according to claim 3, wherein said layer is an apertured formed polymeric film, wherein said apertures have an average diameter of from 100 micrometers to 500 micrometers. 6. A perspiration pad according to claim 3, wherein said breathable backsheet comprises at least two layers, a first layer comprising an apertured layer and a second layer comprising a fibrous layer. 7. A perspiration pad according to one of the preceding claims, wherein said perspiration pad further comprises a topsheet and wherein said absorbent core is intermediate said topsheet and said backsheet. 8. A perspiration pad according to any one of the preceding claims, wherein said pad is an underarm perspiration pad. 9. A perspiration pad according to any one of the preceding claims, wherein said backsheet is provided with garment fastening means. 10. A perspiration pad according to claim 9, wherein said garment adhesive means comprises at least 1 adhesive strip.

Inventors: KEIRAT CHRISTIANE, KEIRAT, CHRISTIANE
Applicants: KEIRAT CHRISTIANE, PROCTER & GAMBLE, KEIRAT, CHRISTIANE, THE PROCTER & GAMBLE COMPANY
Application year: 1997
Main classification: A41D27
IPC codes: A41D27, A61L15