MXPA99005940A - Disposable absorbent article for topical adhesive attachement to the skin of a wearer providing odour control - Google Patents

Abstract

The present invention relates to disposable absorbent articles particularly sanitary napkins, pantiliners, adult incontinence products or sweat pads. In particular the present invention relates to such disposable absorbent articles which are worn by direct attachment to the skin of the wearer in the area were absorption of bodily liquids is desired and which articles are provided with an odour control system.

Description

ABSORBENT ARTICLE DISPOSABLE FOR TOPICAL FIXATION ADHESIVE TO THE SKIN OF A USER THAT PROVIDES CONTROL OF ODOR FIELD OF THE INVENTION The present invention relates to disposable absorbent articles, particularly sanitary napkins, pantiliners, adult incontinence products or sweat pads. In particular, the present invention relates to these disposable absorbent articles which are used by attaching them directly to the wearer's skin in the area where the absorption of body fluids is desired, and which articles are provided with an odor control system.

BACKGROUND OF THE INVENTION The general prior art in this field of disposable articles for topical application to a user's skin is developed particularly in the field of auxiliary bandages, plasters and bandages. These articles, however, are typically applied in an emergency situation, where, for example, a wound has occurred on the user's skin and the absorption of body fluids emanating from a wound is desired. In this context, aspects of the performance of the absorbent article such as comfort and easy application and use, painless removal, discretion are subordinated to criteria such as sterility, protection of healing, mechanical protection of the wound. Also the absorbent articles that protect the wound are widely used in areas of the skin where the body hair can be removed before the application of the absorbent article where little or no hair grows.

The present invention is not related to absorbent articles that protect wounds but are related to absorbent articles for the absorption of body fluids which naturally emanate from a body without a wound. For example, sanitary pads or pantiliners for use in the genital region are these items. Also the incontinence devices that are used, for example, in the genital region or the sweat pads that are used in the region of a person's armpit are the subject matter of the present invention. These items are used to discretely absorb liquids, which otherwise would normally adversely affect the social context of the user of these items. However, the odors that emanate from these items can have the same negative effect or it is, a! less, often perceived as such. These articles are applied to the skin of a user in a region where a considerable amount of hair typically grows, so that the criteria of easy and painless removal of the article is of key importance. These directly applicable articles have generally been disclosed in the inventorial register established by United States law H1602 or WO 96/33683. Some more details of these articles have been considered, for example, in the PCT application NO 95/16424. This document discloses sanitary articles having a body adhesive that is applied on the side facing the user of a sanitary napkin along the entire periphery. The problem underlying this document is mainly the secure attachment to the skin, but it also mentions the problems of disunion of these articles after being used without causing undue pain to a user. The disclosure of WO 95/16424 includes a detailed analysis of the criteria for the body adhesive with respect to the watchmaking criteria. However, this document has little in regard to the problem of painless removal of these articles, since the rheological criteria taught include depilatory compositions (ie, hair removal), which are commercially available such as STREP MIEL ™ sold. in Italy by Laboratori Vaj, SpA The adhesives for topical fixation mentioned in WO 95/16424 include the current pressure sensitive adhesives used to fix sanitary napkins to prior garments., this document only identifies the static rheological characteristics but is reserved as regards the dynamic rheological behavior of a body adhesive. In the international publication WO 96/13238 a model of frequency-dependent body adhesive is disclosed. However, all measurements reported, for example, on page 9 were made at temperatures of -60 ° C and + 120 ° C, and at real frequencies of 0.1 to 100 rad / sec. In order to obtain the necessary data at the application temperature (at approximately 20 ° C typical of the environment of the solution, ie storage temperatures) the Williams-Landel-Ferry equation (hereinafter WLF) was used. The WLF equation is empirical and only valid within certain limits, for example, it can not be used to extrapolate at temperatures below the vitreous transition temperature of the polymeric adhesive, the WLF can not be used on the bases of the values below the glass transition temperature. Details about the WLF equation and its applicability in "Principles of Polymer Processing" can be found by Z. Tadmor and C.G.

Gogos, published by John Wiley & Sons or in "Viscoelastic Properties of Polymers", by J.D. Ferry also published by John Wiley & Sons. Since this is heretofore absent from WO 96/13238 the applicability of the disclosed data can not be determined. Furthermore, this disclosure is not related to the absorbent articles provided with an odor control means.

European patent application EP-638 303 discloses the use of a body adhesive on the side folds of sanitary napkins in order to maintain the folds in a vertical position. The Swiss publication CH-643730 discloses the use of a very long sanitary napkin having beveled outer edges with a body adhesive on the four corners of the outer edges in order to provide an area for the outer body adhesive of the region of the pubic hair growth. It is an object of the present invention to provide absorbent articles with body adhesive, especially sanitary napkins and pantiliners with odor control means, to reduce or even eliminate the odor emanating from the articles. Since the article is applied to the user's skin in close proximity, the perceived and real need for odor control is high, also as the application to the skin provides an odor seal that causes the odors of the absorbed liquid or formed from the absorbed liquid accumulate inside the absorbent article. Therefore, the impression of odor is increased by removing the articles unless active measures are taken to the contrary. Furthermore, it is an object of the present invention to provide disposable absorbent articles for the absorption of natural liquids emanating from a user's body, which are attached to the skin of a wearer while providing painless removal of the absorbent article. It is another object of the present invention to ensure that when removing the absorbent article there is no residual adhesive on the skin or on the user's hair. It is another object of the present invention to provide disposable absorbent articles that are used in such close proximity to the area emanating from the user's liquid, that losses of liquid to the exterior of the absorbent article are minimized or eliminated. For disposable absorbent articles used in the crotch region of a wearer, this will result in improved security against staining of surrounding skin tissue and clothing.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to disposable absorbent articles for topical adhesive attachment to a user of these articles, which comprise an odor control system. The article typically has a surface facing the user and an exterior surface also called a surface facing the garment in the context of the articles used under the clothing. The article comprises an absorbent core structure between the surface facing the user and the surface facing the garment, to absorb the liquids emanating naturally from a user. The disposable absorbent article, according to the invention comprises on at least part of the surface that gives the user an adhesive for the adhesive topical attachment of the article to the skin of a user, and further the article comprises an odor control system to provide a benefit for odor control. In a preferred embodiment according to the present invention the absorbent core comprises the odor control system and, preferably the odor control system comprises particulate odor control agents. It is most preferred that the particulate odor control agents are particles selected from zeolites, gelling absorbent materials, activated carbon, silicas, and combinations thereof. In a particularly preferred embodiment according to the present invention, the garment-facing side of the absorbent article is provided by a backsheet that must be generally impermeable to liquid, and in this preferred embodiment, is at least vapor permeable. of water, in order to provide respirability to the absorbent article. This is particularly preferred because it has been found that the combination of a breathable absorbent article with an odor control system can provide a synergistic increase in the effectiveness of the odor control system. This is particularly so in the context of articles affixed to the wearer's skin, as provided by the present invention. In general, any body adhesive acceptable to the user of an article in accordance with the present invention can be used. However, it is particularly preferred that the adhesive has the following characteristics. The adhesive is particularly characterized as having an elastic modulus at a temperature of 37 ° C (100 ° Fahrenheit) abbreviated G'37 and having a viscous modulus at a temperature of 37 ° C (100 ° Fahrenheit) of G "37. adhesive is selected to have a dynamic elastic behavior such that the difference _G'37 of G'37 at a frequency of 100 rad / sec and G'37 at a frequency of 1 rad / sec not greater than 150%, preferably 80%, of G'37 at a frequency of 1 rad / sec or preferably less than 10000 Pa. The adhesive is further selected to have a dynamic viscous behavior such that the difference _G'3 of G "37 at a frequency of 100 rad / sec and G "37 at a frequency of 1 rad / sec is not greater than 10000 Pa, preferably not greater than 5000 Pa, most preferably no greater than 1000 Pa. It is particularly preferred that the articles according to the present invention have a value of proportion G'37 above G "37 in the total interval of the frequency from 1 to 100 rad / sec greater than or equal to 1, preferably greater than 1.6 and most preferably greater than or equal to 3.3. The value of the ratio G'37 over G "37 at least for the frequency range of 1 to 100 rad / sec may change with the increase in frequency, while it is not necessarily proportional to the change in frequency. G'37 on G "37 should not change within the frequency range by a factor greater than 3, preferably greater than 2, and most preferably should remain constant.

At 1 rad the preferred value of G'37 is below 20000 Pa, preferably it is below 15000 Pa and most preferably still less than 10000 Pa. On the other hand, the value of G "37 at a frequency of 1 rad / sec does not should exceed 15000 Pa, this should preferably be less than 10000 Pa and most preferably still less than 5000 Pa. The above rheological criteria can be satisfied by the adhesive compositions where the composition comprises from 51% to 99.5% of a plasticizer compound or the composition which is liquid at 20 ° C, from 0.5 to 20%, preferably from 5% to 15%, of a polymeric compound or polymer composition which is soluble or swellable in the plasticizer composition or composition, and with a tackifying resin. in an amount of 0% to 600% by weight of the polymeric compound The compound or plasticizer composition is preferably selected from the group consisting of water, alcohols, preferably glycerol, glycols, poly licoles, liquid polybutenes, oils or combinations thereof, while the compound or polymer composition is preferably selected from the group consisting of thermoplastic elastomers of block copolymers, styrene block copolymers, hydrogenated styrene block copolymers. Very generally, the preferred body adhesive is at least partially hydrophobic, preferably 60%, more preferably 80% by weight of the adhesive consists of hydrophobic components and most preferably none of the materials in the adhesive are hydrophilic, ie, it is made entirely from hydrophobic components. In a particularly preferred embodiment with the present invention, the adhesive covers less than 20% or even more preferably less than 10% of the surface facing the wearer of the absorbent article. The present invention is more beneficially applied in the field of sanitary napkins or panty-pads.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to disposable absorbent articles that are applied directly to the wearer's skin. The article exhibits absorbency for bodily fluids, protection against staining of the wearer's garments, a benefit of odor control, improved physical comfort for the user, and is easy to produce and pack. The disposable absorbent article is described below with reference to a sanitary napkin or catamenial product, however, pantiprotectors, adult incontinence articles or sweat pads are also included under the term disposable absorbent articles. AND! term "sanitary napkin" as used herein, refers to an article that is worn by women adjacent to the pudendal region, and which is intended to absorb and contain the various body fluids that are discharged from the body (e.g. , vaginal discharge, menstruation and / or urine), and which is intended to be discarded after a single use. The disposable absorbent article is preferably thin, more preferably within one and 5 mm in thickness and may be either substantially flat before use or in a preconfigured form. The terms "attached" or "fixed", as used herein, encompass configurations by which a first member is directly connected to a second member and configurations by which a first member is directly connected to a second member by connecting the first member to intermediate members, who in turn connect to the second member. In a preferred embodiment, a sanitary napkin of the present invention comprises a liquid permeable upper sheet, a liquid impermeable back sheet attached to the upper sheet, and an intermediate absorbent core to the upper sheet and the back sheet. The sanitary napkin has two main surfaces, a surface that is in contact with the body or that faces the user, and a surface that faces or is in contact with the garment. The upper sheet is docile, soft feeling, and non-irritating to the user's skin. The top sheet can also have elastic characteristics that allow it to be stretched in one or two directions in parts of the upper sheet or in its entire extension. In addition, the top sheet is permeable to fluid allowing fluids (eg menses and / or urine) to easily penetrate through its thickness. A suitable top sheet can be manufactured from a wide range of materials such as woven and non-woven materials; polymeric materials such as thermoplastic films formed with openings, plastic films with openings and hydroformed thermoplastic films; and thermoplastic canvases. Suitable woven and nonwoven materials may be composed of natural fibers (for example wood or cotton fibers) of synthetic fibers (for example, polymer fibers such as polyester, polypropylene or polyethylene fibers or from a combination of natural fibers and fibers). Synthetics or 2 / Multicomponent Fibers Preferred sheets for use in the present invention are typically selected from the upper non-woven sheets with raised upper region, and the upper sheets of film formed with openings. especially preferred for the upper sheets because they are permeable to body exudates and not yet absorbent and have a reduced tendency to allow the fluids to pass back through and rewet the user's skin.Thus, the surface of the film that is in contact with the user remains dry, thus reducing the spotting of the body and creating a more comfortable feeling for the user. Suitable films are described in U.S. Patent Nos. 3,929,135; patent of the States United No. 4,324,246; U.S. Patent No. 4,342,314; U.S. Patent No. 4,463,045 and U.S. Patent No. 5,006,394. Top sheets formed with particularly preferred micro apertures are disclosed in U.S. Patent No. 4,609,518 and U.S. Patent No. 4,629,643. A preferred top sheet for the present invention comprises the film formed in one or more of the above patents and which is marketed in sanitary napkins by The Procter & Gamble Company of Cincinnati, Ohio as "DRI-WEAVE". The upper sheets that do not have a homogeneous distribution of liquid passages but only a part of the upper sheet comprising passages of liquid, are also contemplated by the present invention. Typically these sheets would have the liquid passages oriented in such a way that they result in a centrally permeable upper sheet and peripherally impervious to liquids. The surface facing the wearer of the formed film topsheet can be hydrophilic to help transfer the liquid faster through the topsheet than if the body surface were not hydrophilic. In a preferred embodiment, surfactant is incorporated into the polymeric materials of the formed film topsheet as described in PCT publication WO 93/09741. Alternatively, the surface facing the body of the user of the topsheet can be made hydrophilic by treating it with a surfactant such as described in U.S. Patent No. 4,950,254. Another alternative is the so-called hybrid top sheets which incorporate structures in fibrous and film form, particularly useful embodiments of these hybrid top sheets are disclosed in PCT publications WO 93/09744; WO 93/112725 or WO 93/11726. When reference is made to the top sheet, a multilayer structure or a layer structure is contemplated. The hybrid top sheet mentioned above is a multiple layer design, but other multi-layer top sheets such as the primary and secondary top sheet designs are also considered. The odor control system according to the present invention can also be provided to or with the top sheet. For example, if the odor control system comprises odor masking agents (such as perfumes), these agents may be, for example, sprayed onto a surface of the top sheet. Also microencapsulated odor control agents that are protected against premature escape can be provided on or with the top sheet. The microcapsules depending on their mode of activation, for example, fracture or heat or dissolution, then have a high probability of activation only when needed. However, it is usually preferred to provide the odor control system with the absorbent core. . The absorbent structure or absorbent core may include the following components: (a) optionally a primary fluid distribution layer preferably together with an optional secondary fluid distribution layer; (b) a fluid storage layer; (c) optionally a fibrous layer ("dedusting"), which covers the storage layer; and (d) other optional components.

A Primary / Secondary Fluid Distribution layer An optional component of the absorbent structure according to the present invention is a primary fluid distribution layer and a secondary fluid distribution layer. The primary distribution layer is typically below the top sheet and is in fluid communication with it. The top sheet transfers the acquired fluid to the primary distribution layer for final distribution to the storage layer. This fluid transfer through the primary distribution layer occurs not only in the thickness, but along the longitudinal and wide directions of the absorbent product. The also optional but preferred secondary distribution layer is typically below the primary distribution layer and is in fluid communication with it. The purpose of this secondary distribution layer is to easily acquire the fluid from the primary distribution layer and transfer it rapidly to the underlying storage layer. This helps the fluid capacity of the underlying storage layer to be fully utilized. The fluid distribution layers can be comprised of any typical material for these distribution layers. In particular, the fibrous layers maintain the capillaries between the fibers even when wet, being useful as distribution layers.

B Fluid Storage Layer Positioned in fluid communication, and typically underlying the primary or secondary distribution layers, is a fluid storage layer. The fluid storage layer may comprise any normal absorbent material or combinations thereof. This preferably comprises gelling absorbent materials normally referred to as "hydrogel", "superabsorbents", "hydrocolloid" materials in combination with suitable carriers. The gelling absorbent materials are capable of absorbing large quantities of aqueous body fluids, and are also capable of retaining these absorbed fluids under moderate pressures. The gelling absorbent materials may be dispersed homogeneously or in a non-homogeneous manner within a suitable carrier. Suitable carriers, provided they are absorbent as such, can also be used alone. The gelling absorbent materials for use herein will very often comprise a polymeric gelling material, partially neutralized, lightly crosslinked, substantially insoluble in water. This material forms a hydrogel upon contact with water. These polymer materials can be prepared from polymerizable, unsaturated, acid-containing monomers, which are well known in the art. Suitable carriers include materials that are conventionally used in absorbent structures such as natural, modified or synthetic fibers, ocularly modified or unmodified cellulose fibers in the form of fluff and / or tissue. Suitable carriers can also be used together with the gelling absorbent material, however, these can also be used alone or in combinations. Very preferred are tissue and tissue laminates in the context of sanitary napkins / panty liners. One embodiment of the absorbent structure made in accordance with the present invention comprises a double layer tissue laminate formed by bending the tissue on itself. These layers can be joined together. The gelling absorbent material or other optional material may be comprised between the layers. Modified cellulose fibers such as hardened cellulose fibers can also be used. Synthetic fibers can also be used and include those made from cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (such as Orion), polyvinyl acetate, non-soluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (such as nylon) , polyesters, two-component fibers, three-component fibers, mixtures thereof and the like. Preferably, the surface of the fiber are hydrophilic or are treated to be hydrophilic. The storage layer may also include filling materials, such as Perlite, diatomaceous earth, Vermiculite, etc., to improve liquid retention. If the gelling absorbent material is dispersed in a non-homogeneous manner in a carrier, the storage layer can, however, be locally homogeneous, that is, have a distribution gradient in one or more directions within the dimensions of the coating. storage. The inhomogeneous distribution can also refer to the laminates of carriers that partially or completely enclose the gelling absorbent materials.

C Fibrous Optional Coating ("Dusting") An optional component for inclusion within the absorbent structure according to the present invention is a fibrous layer adjacent to, and typically underlying the storage layer. This underlying fibrous layer is typically referred to as a "dedusting" layer, as it provides a substrate on which the absorbent gelling material is deposited in the storage layer during the manufacture of the absorbent structure. In fact, in those instances where the gelling absorbent material is in the form of macrostructures, such as fibers, sheets or strips, this fibrous "dedusting" layer does not need to be included. However, this "dedusting" layer provides some of the additional capabilities of fluid handling, such as rapid capillary action of the fluid along the length of the pad.

Other Optional Components of the Absorbent Structure The absorbent structure according to the present invention may include other optional components normally present in the absorbent webs. For example, a reinforcing sheet may be placed within the respective layers, or between the respective layers of the absorbent structure. These reinforcement canvases should be of such configuration so as not to form interfacial barriers for fluid transfer. Given the structural integrity that normally occurs as a result of thermal bonding, reinforcing canvases are not normally required for thermally bonded absorbent structures.

Odor control system According to the present invention, the absorbent article comprises as an essential aspect an odor control system. Any odor control agent or combinations thereof known in the art for this purpose can be used herein. The art is replete with descriptions of various odor control agents to be used within absorbent articles in order to address the problem of malodour formation, which can all be usefully employed in the present invention. These agents can typically be classified according to the type of odor that the agent is intended to combat. Odors can be chemically classified as being acidic, basic and neutral. Acid odor control agents have a pH greater than 7 and typically include sodium carbonates, sodium bicarbonates, sodium phosphates, particularly zinc and copper sulfates. The basic odor control agents have a pH less than 7 and include compounds such as carboxylic acids, such as citric acid, láric acid, boric acid, adipic acid, and maleic acid.

Neutral odor control agents have a pH of about 7 examples of these types of compounds include activated carbons, clays, zeolites, silicas, gelling absorbent materials (AGM), and starches. Neutral odor control agents and systems are disclosed, for example, in European Patent 348,978, European Patent 510,619, International Publication WO 91/12029, International Publication WO 91/11977, International Publication WOI 91/12030, International Publication WO 81 / 01643 and in the international publication WO 96/06589. Cyclodextrin and its derivatives can also be used as described in U.S. Patent No. 5,429,628. Alternatively, control systems can be categorized! odor with respect to the mechanism by which odor detection is reduced or prevented. Older smell control agents typically control odor detection through an absorption mechanism. As a consequence, odor control systems that chemically react with malodorous compounds or with compounds that produce malodorous degradation products, thereby generating compounds that lack odor or have an odor acceptable to consumers can also be used herein. . Suitable agents include chelating agents and can be selected from amino carboxylates such as, for example, ethylene amine tetraacetate, as described for example in U.S. Pat. No. 4,356,190, amino phosphonates such as polyfunctionally substituted aromatic chelating agents of ethylenediaminetetrakis (methylene phosphonates), as described in U.S. Patent No. 3,812,044 and mixtures thereof. Without attempting to be bound by theory, it is believed that the benefit of these materials is in part due to their exceptional ability to remove the iron, copper, calcium, magnesium, and manganese, present in the absorbed fluids and their products. degradation by the formation of chelates. Another suitable odor control system, to be used here, comprises a regulatory system, such as citric acid and sodium bicarbonate buffer systems, sodium phosphate and sorbic acid. Also, systems having a pH of 7 to 10 as described, for example, in the international publication WO 94/25077 may be useful in the present invention. An alternative odor control system utilizes ion exchange resins such as those described in U.S. Patent No. 4,289,513 and U.S. Patent No. 3,340,875. Masking agents such as perfumes can also be used as the odor control agents herein. Preferably these agents are used in combination with an additional odor control agent such as zeolite as described in the international publication WO 94/22500. As indicated above, these masking agents in the odor control system may be provided in encapsulated form preferably microencapsulated, which provides the additional benefit of not adversely affecting the ability of the article to be "schmiegsam" (which may be translated lean or flexible in English), as defined in the European patent application EP -A-333-773. Preferred control systems for use herein include the following combinations: i) silica, AGM and zeolites, preferably in a ratio of 5: 1: 1 to 1: 1: 5 :, most preferably 3: 1: 1: a 1: 1: 3; ii) zeolite, activated carbon, and AGM: iii) silica and AGM preferably in a ratio of 5: 1 to 1: 5, more preferably 3: 1 to 1: 3; iv) zeolites and AGM; v) silica and zeolites, preferably in a ratio of 1: 5 to 5: 1 more preferably 1: 3 to 3: 1, vi) chelating agents, particularly ethylenediamine tetraacetate; and vii) chelating agents in combination with any of the odor control systems i) av), preferably in a ratio of 1: 10 to 10: 1, more preferably 1: 5 to 5: 1, most preferably 1: 3 to 3: 1. According to the present invention, the amount of odor control system incorporated in the absorbent article, can be easily determined by the person skilled in the art, and is also dependent on the intended use of the absorbent article, taking into consideration the dimensions of the article. absorbent. Typically, the absorbent article comprises from 5 grams per square meter to 400 grams per square meter, more preferably from 10 grams per square meter to 300 grams per square meter, most preferably from 150 grams per square meter to 250 grams per square meter, base weight of said control system! of the smell. For example, a sanitary napkin or a panty protector may comprise from 0.25 grams to 5 grams, preferably from 0.4 grams to 3 grams, most preferably from 0.5 grams to 2.5 grams of said odor control system. The odor control system may be incorporated into the article by any of the methods disclosed in the art, provided that the elements of the absorbent article and the absorbent article itself meet the specific requirement described herein. For example, odor control agents can be layered on the core of the absorbent material or blended into the fibers of the absorbent core. The odor control system is preferably incorporated between two layers of cellulose tissue within the fluid storage layer. Optionally, the odor control system can be linked between two layers of cellulosic tissue, with for example, a thermal melt adhesive, a polyethylene particle binder or any other suitable bonding system. The backsheet mainly prevents the exudates absorbed and contained in the absorbent core from moistening the articles that are in contact with the absorbent product, such as underpants, briefs, pajamas and undergarments. The backsheet is preferably impervious to liquids (eg, urine and / or menses), and is preferably manufactured from a thin plastic film, although other flexible liquid impervious materials may also be used.

As used herein, the term "flexible" refers to materials that are docile and will readily conform to the contour and general shape of the human body. The back sheet can also have elastic characteristics that allow it to stretch in one or two directions. The backsheet typically extends through the entire absorbent core and can extend over and become part of the top sheet by bending around the absorbent core. In this way a configuration of the top sheet as disclosed in United States Patent No. 4,342,314, column 16, lines 47 to 62 can be achieved without the requirement to selectively perforate the top sheet. The backsheet may comprise a woven or non-woven material, polymeric films such as polyethylene or polypropylene thermoplastic films or composite materials such as a film-coated nonwoven material. Preferably, the backsheet is a polyethylene film having a thickness of about 0. 012 mm to approximately 0.051 mm. Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-1401 and by Ethyl Corporation, Visque in a Division of Terre Haute, Indiana, under the designation XP-39385. The backsheet is preferably embossed and / or finished without gloss to provide a more fabric-like appearance. Preferably, the backsheet also provides breathability to the absorbent article by being at least permeable to water vapor, preferably permeable to air, however, without compromising the main function of the backsheet.

The backsheet can be a laminated material, for example, of a combination of microporous film, nonwoven material and / or film formed with openings. The breathability, if desired, can be limited to the periphery of the backsheet or this can be through the entire back sheet. Preferably, the backsheet can be a microporous film which comprises as an inert filler an appropriate odor control material, while also providing a barrier against malodor.

Adhesive for topical The articles according to the present invention, as said, are applied directly to the user's skin. In particular, sanitary napkins are applied in the genital region of a typically female user, around the liquid discharge area. The word "skin" according to the present invention is not only related to the specific dermis of the user, but includes the mucosal tissue as well as the hair typically found in the genital region of the users, for example, of the sanitary towels. In order to provide fixation of the lateral folds according to the present invention to the user's skin, it is necessary to provide a certain area on the side of the top sheet of the article which is facing the user, with a adhesive for topical fixation also referred to as body adhesive. Various designs are contemplated in this respect, but preferably the body adhesive is provided, along the peripheral edge of the top sheet such that a central area of the article is left without adhesive. This will more appropriately facilitate the positioning of the article such that the liquid-permeable upper sheet without adhesive on it, is placed adjacent to the orifice that emanates the body fluid, in such a way that the liquid that emanates is immediately transported towards the absorbent structure of the body. absorbent article without the possibility of leaks or spills. However, it is not necessary that the body adhesive be provided in a closed circle around the edge of the top sheet, but that it can be provided in incremental areas such as discrete points or lines in such a way as to disengage between the different places. of fixation providing additional comfort to the user of these items. While any body adhesive that is acceptable to the user of an article in accordance with the present invention may be used, it is particularly preferable that the following conditions be satisfied.

Physical, Physical, and Adhesive Characteristics of a Topical Adhesive Even when topical adhesives similar to pressure sensitive adhesives are used in human skin hair and mucosal tissues, it is understood that topical adhesive compositions can only with difficulty be considered typical pressure sensitive adhesives (referred to as PSA in the following) on the basis of the rheological behaviors, more characteristic that identify these materials. In fact, as the person skilled in the art of adhesives knows, the most characteristic aspect that distinguishes a PSA from other substances that can temporarily stick things (as can, for example, water), is the fact that its rheological and especially the elastic modulus G 'varies greatly with the frequency of the applied stresses. More particularly the G 'of the PSA may increase over some types of magnitude while the frequency of the applied voltages varies from the typical binding frequency to the typical disbudding frequency, i.e. from 1 rad / sec to 100 rad / sec as is indicated below.

As a first consequence, it is inferred that it is inadmissible to define materials intended to be used as "adhesives", giving values of the rheological parameters and especially of G 'to a fixed frequency value. This can be misleading because in the absence of other features it will include materials that do not have practical values. It is believed by consequence that the rheological characterization should be based on dynamic considerations. This applies not only to the elastic modulus G 'but also to the viscous modulus G "and consequently also to (d) = G7G' It is well known that the typical PSA does not have only a high variation of G 'through the frequencies considered, but there is also a variation of G "even higher that may be close to or even higher than the value of G ', that is (d) becomes approximately or even higher than 1, particularly in the frequencies that are typical of disunity. Without wishing to be bound by theory, this can be interpreted as meaning that a high fraction of the energy applied for disunity dissipates in internal fractions (so that it is not effective in causing disunity), while this fact causes macroscopically the registration of a very high level of adhesive force. In order to provide good bonding conditions, ie at a frequency of about 1 rad / sec, the absolute values of the elastic modulus should not be too high, otherwise the adhesive is too hard and is not capable of binding or molding intimately to the surface to which it is expected to adhere. It is also important to have an absolute value of G "low in order to have good cohesion, which is particularly valuable for a direct application on the human body, while the material remains soft and able to adhere gently to the skin.

Finally, the person skilled in the art will also recognize that the Vitrea Tg Transition Temperature of the PSA is a parameter that is useful to more fully define the group of useful PSA materials. As indicated above, the materials useful as body adhesives according to the present invention have rheological characteristics which are measured at a reference temperature of 37 ° C, such as body temperature, and within a frequency range. It has been found that when applying an article with a body adhesive, the adhesive contact is formed at a low frequency, while the disengagement occurs at the speed of removal of the article. This speed is expressed as a frequency of 100 rad / sec whereas it has been found that the low frequency of forming the adhesive bond is in the order of 1 rad / sec. Therefore, the range of frequencies to be used according to the present invention is between 1 and 100 rad / sec. The following set of characteristics must be met: in the frequency range, the percentage variation of the elastic modulus G'37 is less than or equal to 150%, preferably less than 100% and more preferably less than 80%, from G'37 to 1 rad / sec, preferably the variation is less than 10000 Pa in absolute terms. This is satisfied by the body adhesive exemplified below, while, for example, Promeon RG-63B, cited in the prior art, shows in the same frequency range a variation of G'37 of 331%, which is not acceptable according to the present invention. in the frequency range the variation of the viscous modulus G "37 is not greater than 10000 Pa, preferably not greater than 5000 Pa, most preferably not greater than 1000 Pa. the value of the proportion G'37 / G" 37 at least for the frequency range from 1 rad / sec to 100 rad / sec should preferably be the unit or higher, more preferably 1.6 or higher and most preferably 3.3 or higher, while not exceeding approximately 50. It should be noted that G 'and G " in the application frequency of 1 rad / sec at 100 rad / sec are taken at a temperature of 37 ° C. In the practical use of the articles according to the present invention, the actual storage temperature of the article and consequently the The temperature of the body adhesive when applied varies widely, for example, storage in a hot bath near a radiator can reach up to about 37 ° C, while storage in a storage room or bathroom without heating However, since the article in accordance with the present invention is used directly on the skin and the user typically does not want to be applied to an article too cold, the temperature with a window open during the winter can be close to 0 ° C. Actual body adhesive will reach 37 ° C very quickly or even be heated by the user before application. Consequently, it is believed that the characteristics of the adhesive bond are selected in a manner very appropriate to body temperature. As indicated above, the rheological behavior can also be related to the values of the Transition Temperature Vitrea Tg. For body adhesives according to the present invention, the Tg should preferably be less than -15 ° C, more preferably less than -20 ° C and most preferably less than -25 ° C.

Preferred Chemical and Composition Characteristics of a Topical Adhesive In order to meet the requirements of the above preferred rheological and physical characteristics of a body adhesive, the following formulation criteria can be used. It should be noted that most of the compositions useful as the body adhesive have a substantially gel-like structure and are preferably gels. This derives from the fact that: the predominant component is a liquid material at room temperature. a macromolecular or polymeric component is present in minor amounts against the plasticizer. This form, in the preferred modalities, a three-dimensional network made by the physical and chemical bonds between the molecules. Particularly useful physical links are the bonds present in systems containing block thermoplastic elastomers. More specifically, the compositions comprise: from 0.5 to 20%, preferably from 5% to 15%, by weight of a macromolecular polymer substance or a mixture of these substances soluble or capable of swelling in the aforementioned plasticizer (s). As non-limiting examples, these polymeric or macromolecular substances can be natural and / or synthetic, such as natural gums or derivatives such as natural gums and gelatins, their derivatives and alginates; polyacrylics; polyvinyl alcohol; polyethylene oxide; polyvinylpyrrolidone (PVP) or polyvinyl ethers, their copolymers and derivatives; cellulose derivatives; Thermoplastic Block Copolymer Elastomers and preferably Styrenic Block Copolymers and more preferably the hydrogenated grades Styrene / Ethylene-Butylene / Styrene (SEBS), / Styrene / lsoprene / Styrene (SIS), and Styrene / Ethylene-Propylene / Styrene (SEPS) . from 51 to 99.5% by weight of a plasticizing substance or a mixture of plasticizing substances, which are liquid at room temperature. As non-limiting examples, the plasticizer may be water, various alcohols (such as in particular glycerol), glycols, polyglycols, liquid polybutenes, natural or synthetic oils such as vegetable oils, mineral oils, or combinations thereof. from 0 to 600% by weight of a macromolecular polymer substance of a tackifier resin whose main scope is to form the Tg especially in systems based on synthetic polymers. from 0 to 10% and more preferably from 0 to 5% by weight of a substance to facilitate and stabilize the gelation of both the hydrophobic and hydrophilic liquid plasticizers. These can be for oil systems, for example, C8 to C22 fatty acids, their metal salts and their polyoxyl derivatives; lanolin derivatives, silica; bentonite, montmorillonite and its derivatives; polyamides, waxes or mixtures thereof. Common additives known in the art such as preservatives, antioxidants, anti-ultraviolet agents, pigments, mineral fillers, rheology modifiers, etc. may also be comprised in amounts of up to 10% each. When chemical lattices are formed in the system, a crosslinking agent may be present in amounts of up to 5% by weight. The chemical crosslinking can also be formed by the mutual neutralization of the polymers that have • different functionalities such as in the reaction between polyacrylic acids and polysaccharides. Typical compositions for body adhesives can be divided into three families according to the nature of their main component, i.e., normally plasticizer or liquid plasticizers (s): 1) Hydrophobic compositions in which the plasticizer is typically a oil or mixtures of oils of vegetable and mineral origin and the polymer is usually a synthetic polymer, preferably an elastomer, soluble or capable of swelling in the oil or in the oils. 2) Mixed phase compositions in which both hydrophobic and hydrophilic components, possibly in both the plasticizers and the polymers, form two or more separate phases. In these cases, an emulsifier / surfactant is preferably present at a suitable level to form stable emulsions between the incompatible phases. For body adhesives according to the present invention, it is preferable that the hydrophobic components are predominant against the hydrophilic components. 3) Hydrophilic compositions in which typically the plasticizer is water / glycerol / glycols and the like and / or mixtures thereof and the polymer phase is of synthetic (for example polyacrylics), or natural (for example natural gums) or mixtures thereof. It is important that, unlike what is already known in the medical field and the prior art cited, hydrophilic compositions are not preferred, although hydrophobic and mixed phase compositions 1) and 2) are preferred in the applications of the present invention. This partly depends on technical reasons in the sense that many of the hydrophilic compositions used in the medical field show elasticity and cohesion too low to be useful in the present application. The other reason for preferring the hydrophobic or easily mixed compositions is that the application of the present invention, particularly in the field of sanitary napkins, will include a likelihood of contacting the body adhesive with the liquid being absorbed. Since the liquids are, all of a general aqueous type, in contact with a hydrophilic body adhesive, it would result in a certain absorption of the body fluids in the body adhesives. This would then have the result of changing the rheological characteristics, and therefore the functionality of the body adhesive, causing an unhygienic appearance but also causing the body fluids to remain in direct contact with the skin for a prolonged period, which is not typically desired by none of the disposable absorbent articles according to the present invention. In addition, this can also constitute a potential disadvantage for the user, since some of the hydrophilic compositions are potentially good growth media for the growth of many microorganisms, including still pathogens. In addition, the hydrophilic body adhesive also tends to be perceived as cold and damp when the application of a sanitary pad or sweat pad of the new armpit is not in line with the typical expectation of the consumer. Additional problems result from the fact that in particular body adhesives comprising water as the plasticizer, they have a tendency to dry unless sealed within an impermeable package. The absorbent articles according to the present invention can be made by any of the ordinary manners in the art. The application of the adhesive to the side of the top sheet of the absorbent article should not cause greater problems for those skilled in the art, since it can be provided by similar techniques as are commonly used for a panty fastener device for sanitary napkins. The total area of the surface that faces towards e! The user of the absorbent article that is covered by the body adhesive must not be greater than 20%, preferably not greater than 10%. Preferably, the adhesive is encircling the periphery of the absorbent article and in the case of the upper sheets of film (or when the backsheet is folded over the top sheet) the adhesive is preferably on a part of the film, which is not permeable to liquids. The body adhesive on the item (as is common with panty bras), needs to be protected before use. This protection can be provided by a release liner such as a paper treated with silicone or surfactant, provided that this paper is a good release surface for the particularly selected body adhesive. In principle, the absorbent article according to the present invention is held in the user by the body adhesive and does not require additional supports to remain in place. However, it is possible to provide, for example, a sanitary napkin with a slip-resistant coating on the side of the backsheet in order to prevent the sanitary napkin from gradually migrating out of position. Even when the panty fastener adhesives are not desired and consequently are not preferred according to the present invention, they are not strictly speaking, excluded in the context of the present invention, EXAMPLE 1 An oil-based composition useful in the present invention was mixed using 9.9% by weight of Krato G-1651. A styrene / ethylene / butylene / styrene block copolymer containing 33% by weight of styrene and available from Shell Co., and 59.3% by weight of Kaydol, a paraffinic mineral oil available from Witco Co. Further the composition contains 301 parts of the tackifier resin per 100 parts of the Kraton polymer. The tackifying modifier resin was Escorez 5300, a hydrogenated resin available from Exxon Co. Magnesium stearate, available, was added from Cario Erba S.P.A. a cogelling people for the oil at a level of 0.7% by weight. Iranox 1010 was added an antioxidant available from Ciba-Geigy, at a level of 0.3% by weight. Finally, the formulation had the following percentage composition: Kraton G-1651 9.9% by weight Kaydol 59.3% by weight Esocrez 5300 29.8% by weight Magnesium stearate 0.7% by weight Irganox 1010 0.3% by weight The composition showed the following rheological properties at 37 ° C. a) Elastic modulus at 1 rad / sec, G'37 = 6876 Pa b) Proportion between Elastic and Viscous Modules at 1 rad7sec G'37 / G "37 = 12.49 Proportion between Elastic and Viscous Modules at 100 rad / sec, G, 37 / G "37 = 7.01 c) The ratio of G'37 to 100 rad / sec on G'37 at 1 rad / sec was 1,308. The above formulation was judged as comfortable for the application on the foot! Hairy, sensitive.

COMPARATIVE EXAMPLE A composition based on compound oil was mixed using 7.1% by weight of Kraton G-1651, a styrene / ethylene-butylene / styrene block copolymer containing 33% by weight of styrene and available from Shell Co. , and 49.9% by weight of Kaydol, a paraffinic mineral oil available from Witco Co. Moreover, the composition contained 704 parts of tackifier resin per 100 parts of the Kraton polymer. The tackifying modifier resin was Regalrez 3102, a hydrocarbon resin available from Hercules Co. The available Magnesium Stearate from Cario Erba S.p.A. It was used as a cogelling agent for the oil at a level of 0.7% by weight. Irganox 1010, an antioxidant agent available from Ciga-Geigy, was added at a level of 0.3% by weight. Finally, the formulation had the following percentage composition: Krato G-1651 7.1% by weight Kaydol 41.9% by weight Regalrez 3102 50.0% by weight Magensium stearate 0.7% by weight Irganox 1010 0.3% by weight The composition showed the following rheological properties at 37 ° C. a) Elastic modulus at 1 rad7sec G'37 = 3059 Pa b) Proportion between elastic and viscous moduli at 1 rad / sec G'37 / G "37 = 2.53 Proportion between the visocose elastic moduli at 100 rad / sec, G ' 37 / G "37 = 0.74 c) The G'37 ratio at 100 rad / sec on G'37 at 1 rad / sec was 4.944 The above formulation was judged to be highly uncomfortable for application to forearm skin. The application to sensitive hairy skin was unacceptable.

Claims (10)

1. CLAIMS 1. A disposable absorbent article for topical adhesive attachment to a user of said article, the article having a surface facing the wearer and a garment facing surface and comprising an absorbent core between the surface facing the wearer and the wearer. a surface facing the garment, characterized in that the article comprises on at least part of the surface that gives the user a topical adhesive fixing adhesive of the article, and said article comprises a control system for the article; smell to provide a benefit of odor control. The disposable absorbent article according to claim 1, wherein said absorbent core comprises said odor control system, preferably the odor control system comprises particulate odor control agents, most preferably said odor control agents. Particulate odors comprise particles selected from zeolites, gelling absorbent materials, activated carbon, silicas, and combinations thereof. 3. The disposable absorbent article according to any of the preceding claims, wherein the surface facing the garment is provided by a breathable backsheet. The disposable absorbent article according to any of the preceding claims, wherein said adhesive for topical adhesive fixation having an elastic modulus at the temperature of 37 ° C (100 ° F), G'37 and having a viscous modulus at a temperature of 37 ° C (100 ° F), G "37, said adhesive being selected to have a dynamic elastic behavior in such a way that the difference, _G'37, of G'37 at a frequency of 1 rad / sec and G "37 at a frequency of 100 rad / sec is not greater than 150% of G'37 at a frequency of 1 rad / sec, preferably not greater than 10000 Pa, and the adhesive selected to have a dynamic viscous behavior of such that the difference _G "37, of G" 37 at a frequency of 1 rad / sec, and G "37 at a frequency of 100 rad7sec is not greater than 10000 Pa, preferably not greater than 5000 Pa, most preferably no greater 1000 Pa. 5. The absorbent article according to any one of the pre-claims. cedants, wherein G'37 is less than 20,000 Pa, preferably less than 15,000 Pa, most preferably less than 10,000 Pa, at a frequency of 1 rad / sec. The absorbent article according to any of the preceding claims, wherein G'37 is less than 20,000 Pa, preferably less than 15,000 Pa, most preferably less than 10,000 Pa, at a frequency of 1 rad / sec. The absorbent article according to any of the preceding claims, wherein the adhesive is a composition of materials comprising from 51% to 99.5% by weight of a plasticizing compound or composition which is liquid at 20% C; 0.5% to 20% by weight of a compound or polymer composition that is soluble or swellable in the plasticizer composition or composition; a tackifying resin in an amount of 0% to 600% by weight of the compound or the polymer composition. 8. The absorbent article according to claim 7, wherein said plasticizer compound or composition is selected from the following group: water, alcohols, glycols, oil or combinations thereof; and said polymeric compound or composition is selected from the following group: block copolymer thermoplastic elements, styrene block copolymers, and hydrogenated styrene block copolymers. The absorbent article according to any one of the preceding claims, wherein said adhesive is at least partially hydrophobic, preferably 80% by weight of! adhesive consists of hydrophobic components and most preferably all the components of the adhesive are hydrophobic. The absorbent article according to any of the preceding claims, wherein the adhesive covers less than 20%, preferably less than 10%, of said surface facing the user.