CZ217499A3 - Disposable absorption article for sage, external adherent attachment to bearer skin - Google Patents

Abstract

The invention relates to disposable absorbent articles, in particular sanitary napkins, panties, incontinend products adults, or sweat-sucking pads, especially pactaks disposable absorbent articles worn by their own attaching the wearer ' s skin to the baldness where the absorption requirement is body fluids. These absorbent articles contain, for better external appearance adhering the product to at least a portion of the surface facing the adhesive carrier, with the appropriate rheological characteristics where the key significance of the characteristics adheres the relationship between the modulus of elasticity of amodulem viscosity, as well as their dynamic behavior.

Description

Technical field

The present invention relates to disposable absorbent articles, in particular sanitary napkins, panty liners, adult incontinence products, or sweat pads. In particular, the present invention relates to such disposable absorbent articles which are worn by directly attaching them to the wearer's skin in an area where fluid absorption is desired. The external adhesive attachment of these products needs to be safe and comfortable when applying and wearing, and at the same time there is no discomfort when removing the product. This is achieved by the present invention, which selects the respective rheological (deformation behavior related) characteristics of the adhesives for these products.

BACKGROUND OF THE INVENTION

The general prior art in the field of disposable absorbent articles for external application to the wearer's skin is particularly developed in the field of leucotapes, patches and dressings. However, these products are typically used in emergency situations where, for example, the wearer has been cut, and absorption of body fluids from the wound is desirable. Against this background, aspects of the performance of a particular absorbent article, such as convenient and easy to use and apply, painless removal and unobtrusiveness, are subject to measures such as sterility, healing support and mechanical wound protection. These wounds covering the absorbent articles are also mostly used in areas of the skin where hair can be removed before application of the absorbent article or where no hair grows.

The present invention does not relate to absorbent articles that cover wounds, but relates to absorbent articles for absorbing body fluids that naturally flow out of the body without any wounds. Such articles are, for example, sanitary napkins or panty liners for use in the genital area. The present invention also relates to devices worn in the incontinence of the genital area or sweat suction pads worn by persons under the armpit.

These products are applied to the skin of the wearer in an area where a significant amount of hair typically grows, so that aspects of easy and painless removal of the article are of key importance. Such articles are generally described in the description of the invention US H 1602 or WO96 / 33683. More details about these products are considered, for example, in PCT application WO 95/16424. Described herein are sanitary articles having an adhesive for applying to the body that is applied along the entire circumference to the side of the sanitary napkin facing the wearer. The problem accompanying this document is in the first place a secure attachment to the skin, but also the problems of releasing these products after use, without causing undue pain to the wearer, are also mentioned.

The disclosure of WO 95/16424 discloses a detailed analysis of the scales for an adhesive to be applied to the body, with respect to rheology aspects (i.e., the general teachings on the deformation behavior of substances). However, this document pays little attention to the problem of painless removal of these products because the rheological measures mentioned include epilatory, i.e. hair removal, products commercially available such as SHELF MIELE, sold in Italy to Vaj SpA Laboratories. are mentioned in WO 95/16424, they also include today's self-adhesive adhesives which are used to attach sanitary napkins to undergarments. Furthermore, this document identifies only static rheological characteristics, but does not speak of the dynamic rheological behavior of the body adhesive.

WO 96/13238 discloses a body-to-body adhesive model which is dependent on the frequency (frequency) of the applied stresses (stresses, pressures; hereinafter referred to as "loads"). However, all the measurements described, for example on page 9, were performed at temperatures between -60 ° C and + 120 ° C and at actual applied load frequencies from 0.1 to 100 rad / sec. In order to obtain the necessary data at the loading temperature (about 20 ° C, typical bath, i.e. storage temperature), the equation of Williams, Landel and Ferry (hereinafter referred to as WLF) was used.

The WLF equation is empirical and does not apply within certain limits, for example it cannot be used to extrapolate (ie to estimate) temperatures below the glass transition temperature of a polymer adhesive, and the WLF equation cannot be used based on the values obtained below the glass transition temperature. Details of the WLF equation and its applicability can be found in "Polymer Processing Principles" by Z. Tadmor and C.G. Gogos, published by John Wiley and Son, or in "Viscoelastic Properties of Polymers," by J.D. Ferry, also released from ··························· · · ························ 99

John Wiley and Son. Since this is already lacking in WO 96/13238, the applicability of the described data cannot be evaluated.

European patent application EP-638 303 discloses the use of an adhesive to be applied to the body on the side cuffs of sanitary napkins in order to keep these cuffs in an upright position. Swiss publication CH-643730 discloses the use of a very long sanitary napkin having bevelled outer edges, with body-facing adhesive at the four corners of these outer edges, to provide an area of body-adhesive adhesive sufficiently outside the pubic hair region.

Accordingly, it is an object of the present invention to provide disposable absorbent articles for absorbing naturally flowing fluids from the wearer ' s body that are securely attached to the wearer's skin at the time of application and during wear. However, these articles adhered to the body also need to provide a painless removal of the absorbent article. It is yet another object of the present invention to ensure that no adhesive remains on the skin or on the wearer's hair when the absorbent article is removed. It is a further object of the present invention that the external adhesive does not cause cold or otherwise unacceptable temperature sensations upon application of the article despite the temperature difference of the adhesive with respect to skin temperature. It is a further object of the invention to provide a disposable absorbent article that is worn in close proximity to the area of fluid flow from the wearer's body such that fluid loss to the exterior of the absorbent article is minimized or eliminated. For disposable absorbent articles worn in the crotch region of the wearer, this results in increased confidence in the contamination of the surrounding skin tissue and clothing.

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In addition to the aforementioned objects of the present invention, it is also desirable that sanitary napkins, panty liners and menstruation products reduce or even eliminate the odor emanating from the article, since its application to the wearer's skin provides an odor seal which prevents odors from absorbed liquid. or formed from the absorbed fluid to get away from the absorbent article.

SUMMARY OF THE INVENTION

The present invention relates to disposable absorbent articles for the outer adhesive to the wearer. This article typically has a wearer facing surface and an outer surface, in the context of articles worn under clothing, also called a garment surface. The article includes an absorbent core structure between a wearer facing surface and a garment facing surface to absorb fluids naturally flowing from the wearer's body. The disposable absorbent article of the present invention comprises an adhesive for at least a portion of the wearer facing surface for externally adhering attachment of the article to the wearer's skin.

A detailed analysis of the sequence of common situations occurring after the application of a disposable absorbent article until removal (removal) has now shown that it is necessary to meet very specific adhesive characteristics in order to achieve the desired performance targets, in particular a secure fit during wear and eventually his painless removal. The characteristics considered in this context are the modulus of elasticity, describing the elastic behavior of a particular material, and the modulus of viscosity, which describes the viscous (viscous) behavior of the adhesive material.

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The viscous behavior of the adhesive can be interpreted as representing the ability of the adhesive to attach quickly and securely adhere. Elastic behavior can be explained as an indicator of the "hardness" of the adhesive. Its value is also critical for a good initial attachment. It is believed that their combination is an indicator of the required removal force. The relationship between the modulus of elasticity and the modulus of viscosity is considered to be indicative of what fraction of the removal energy will be dispersed within the adhesive and what portion thereof will be available to initiate the actual removal.

In order to provide disposable absorbent articles that meet the requirements of initial secure attachment, secure attachment during wear and easy / painless removal, the relationship between the elastic modulus and the viscosity modulus, as well as their dynamic behavior, is crucial.

The adhesive has a modulus of elasticity at 37 ° C (100 ° C)

Fahrenheit), abbreviated to 6 ^Σ 37, and has a viscosity modulus at 37 ° C (100 ° Fahrenheit), G ^II: 37. The adhesive further has a dynamic elastic behavior defined as -G ¹ 31, which is a difference of 6 * 37 at frequency applied frequencies (stresses, pressures; hereinafter referred to as “applied loads”) 100 rad / sec. and GA? at a applied load frequency of 1 rad / sec .; and a dynamic viscous behavior of -G ^II 37, which is the difference from GI ^{1 C} 37 at a applied load frequency of 100 rad / sec. and G ^{i: r} 37 at a applied load frequency of 1 rad / sec.

The products of the present invention include an external adhesive that meets the following conditions.

G ^I 37 (1 rad / sec.) Is in the range 1500 Pa to 20000 Pa, preferably 1500 Pa to 15000 Pa, most preferably 3000 Pa to 10000 Pa.

G ^{I: I} 37 (1 rad / sec) is in the range of 100 Pa to 15,000 Pa, 9 Ftft preferably 100 Pa to 10,000 Pa, most preferably 300 Pa to 5,000 Pa.

^Ratio g '37 (1 rad / sec.) / G ^IT 37 (1 rad / sec.) Is in the range from 2 to 50, preferably 3 to 30

0 ^ -37 (100 rad / sec) - G ^IJ 37 (100 rad / sec) ratio: -------------------------- --------------- G ^J 37 (1 rad / sec) - G ^TI 37 (1 rad / sec) is not less than 0.5, preferably in the range of 0.7 to 3, most preferably in the range of 1 to 1.8, the ratio of either ^T -G 37 / G ^I 37 (1 rad / sec.) is not greater than 1.5, preferably not greater than 1 and most preferably not greater than 0.8, or -G ^I 37 is not greater than 10000 Pa, preferably less than 5000 Pa, most preferably less than 2000 Pa, or both.

- The value of the ratio G ^I 37 / G ^{i: r} 37, at least for the frequency range of the applied loads from 1 to 100 rad / sec, should preferably be 2 or higher, more preferably 3.3 or higher, although nowhere in this range the loading does not exceed about 50, preferably 30.

The rheological behavior (i.e., generally the deformation behavior of substances) may also be related to the glass transition temperature values Tg. In the body adhesive of the present invention, the T g should preferably be less than -15 ° C, more preferably less than -20 ° C, and most preferably less than -25 ° C.

······ tt 90 99

9 9 9 0 9 9 9 9 9 9

9 9 9 9 9 9 0 0 0

0 9 0 9 0 000 000 900

9 0 9 9 9 0 9 0

9999 90 99 90 99 ·· - The rheological behavior and acceptance of a disposable absorbent article comprising an external adhesive may also be related to the specific heat capacity. The specific heat capacity of the external adhesive is preferably less than 4 J / g / K, more preferably less than 3 J / g / K and most preferably less than 2 J / g / K.

The rheological behavior and acceptance of a disposable absorbent article comprising an external adhesive may also be related to the specific (specific) thermal conductivity. This specific thermal conductivity is preferably greater than 0.1 W / m / K, preferably greater than 0.6 W / m / K and most preferably greater than 1 W / m / K.

Provided that the above rheological conditions are met, these adhesives will also satisfy conditions such as sufficient cohesiveness (to prevent residual adhesive residues on the skin) that is critical to the commercial use of these adhesives and apparent to those skilled in the art. Adhesive compositions which meet the above criteria may be used as topical adhesives for disposable absorbent articles, provided that they also meet the normal safety requirements of their use on the human skin during and generally after removal of the article.

Measures of hygienic appearance and a pleasant touch feel are also important, so preference is given to adhesive compositions that are transparent or white and prevent a cold, discomfort when applied.

The above rheological measures and other considerations can be accomplished by adhesive compositions which comprise from 51% to 99.5% of a softening compound or composition that is liquid at 20 ° C; from 0.5 to 20%, preferably 5 to 15%, of a polymer compound or mixture that is soluble or swellable in the softening compound or mixture; and adhering the resin-increasing amount in the range of 0% to 600% by weight of the polymer compound. The plasticizer compound or mixture is preferably selected from the group consisting of water, alcohols, preferably glycerol, glycols, polyglycols, liquid polybutenes, oil or combinations thereof, while the polymer compound or mixture is preferably selected from block copolymer thermoplastic elastomers, styrene block copolymers and hydrogenated styrene block copolymers.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to disposable absorbent articles which are applied directly to the user's skin. The present product exhibits body fluid absorbency, protects the wearer ' s undergarments from contamination, has enhanced physical comfort for the wearer, is easy to manufacture and pack. This disposable absorbent article is described below by reference to a sanitary napkin or sanitary napkin, but the term disposable absorbent articles also includes panty liners, adult incontinence products, or sweat suction pads ("wadding"). The term "sanitary napkin, as used herein, refers to a product worn by women adjacent to their pudendal (pubic) region, and the retention is intended to be used to absorb and various body fluids (fluids) that are excreted from the body ( eg vaginal secretions, menses and / or urine), and are expected to be discarded after a single use. The disposable absorbent article is preferably thin, more preferably between 1 and 1.5 mm thick and either substantially flat before use or in a preformed form.

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99 99 99 99 99

The terms "bonded or" attached, as used herein, include arrangements by which a first portion is directly attached to a second portion, and those arrangements by which the first portion is attached to a second portion indirectly by attaching the first portion to intermediate portions that are in turn connected to the first part.

In a preferred embodiment, the sanitary napkin of the present invention comprises a liquid pervious topsheet, a liquid impermeable backsheet attached to the topsheet, and an absorbent core encapsulated between the topsheet and the backsheet. The sanitary napkin has two main surfaces, a body contacting surface of the wearer, and a surface facing or contacting the garment.

The topsheet is flexible, soft feeling and non-irritating to the wearer's skin. The topsheet may have elastic characteristics allowing it to be stretched in one or two directions in portions of the topsheet or throughout its extension. Further, the topsheet is liquid pervious and allows fluids (e.g., menses and / or urine) to readily penetrate through its thickness. A suitable topsheet may be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as apertured formed thermoplastic films, apertured plastic films and hydroformed thermoplastic films and thermoplastic scrims. Suitable woven and nonwoven materials may be composed of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymer fibers such as polyester, polypropylene or polyethylene fibers), bicomponent fibers, or a combination of natural and man-made fibers, or multi-component fibers.

Preferred topsheets for use in the present invention are typically selected from highly expanded, nonwoven topsheets and apertured formed film topsheets. Perforated φφ φφφφφφφφφφφφ

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Molded films are particularly preferred for the topsheets because they are permeable to body exudates and yet remain non-absorbent, and have a reduced tendency to allow fluids to flow back and rewet the wearer's skin. Thus, the surface of the formed film that is in contact with the wearer remains dry, thereby reducing body contamination and creating a more comfortable feel for the wearer. Suitable formed films are described in U.S. Patent 3,929,135;

U.S. Pat. No. 4,324,246; U.S. Patent 4,342,314; U.S. Patent 4,463,045; and U.S. Patent No. 5,006,394. Particularly preferred, micro-apertured formed film topsheets are described in U.S. Patent No. 4,609,518 and U.S. Patent No. 4,629,643. A preferred topsheet for the present invention includes the molded film described in one or more of these patents. and sold on sanitary napkins by The Procter & Gamble Company of Cincinnati, Ohio under the trademark " DRI-WEAVE.

The present invention also envisages topsheets not having a homogeneous (homogeneous) distribution of fluid passageways, but only a portion of the topsheet comprising fluid passageways. Typically, such layers would have fluid paths oriented so as to result in a mid-permeable and peripherally impermeable topsheet.

The wearer facing surface of the formed film topsheet may be hydrophilic to facilitate fluid transfer through the topsheet faster than if the surface was not hydrophilic to the body. In a preferred embodiment, an active surfactant is incorporated into the polymeric materials of the formed film topsheet as described in PCT publication WO 93/09741. Alternatively, the wearer facing surface of the topsheet may be rendered hydrophilic by treating it with a surfactant, as described in US 4,950,254.

Yet another alternative is the so-called "hybrid topsheets, which have incorporated fibrous and film-like • 0 00 * 0" 00 00 00 000 000

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0000 00 00 00 00 00 structures, particularly useful embodiments of such hybrid topsheets are described in PCT publications WO 93/09744; WO 93/11725 or WO 93/11726.

When referring to the top layer, the multilayer or monolayer structure is anticipated. The hybrid topsheet mentioned above is such a multilayer embodiment, but other multilayer topsheets are contemplated, such as those with primary and secondary topsheets.

The absorbent structure or absorbent core may comprise the following components: (a) optionally a primary fluid distribution layer, preferably together with a secondary fluid distribution layer; (b) a fluid storage layer; (c) optionally a fibrous (dust) layer lying beneath the storage layer; and (d) other optional components.

(a) Primary / secondary fluid distribution layer

One of the optional components of the absorbent structure of the present invention is a primary fluid distribution layer and a secondary fluid distribution layer. The primary fluid distribution layer typically lies below the topsheet and is in fluid communication therewith. The topsheet 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 thickness, but also along the length and width directions of the absorbent article.

Also, an optional but preferred secondary fluid distribution layer typically lies below the primary fluid distribution layer with which it is in fluid communication with the fluid. The purpose of this secondary distribution layer is to readily receive capacity at the bottom of the storage layer that has been fully utilized.

The fluid distribution layers may be composed of any material typical of the distribution layers. Fiber layers which hold the capillaries between the fibers even when wet are particularly useful as these distribution layers.

(b) Fluid storage layer

The fluid storage layer is placed in fluid communication with and typically lies below the primary or secondary distribution layers. The fluid storage layer may comprise any conventional absorbent material or combinations thereof. Preferably, it comprises absorbent gelling materials which are generally referred to in conjunction with suitable carriers such as hydrogel, superabsorbent and hydrocolloid materials.

These absorbent gelling materials are capable of absorbing large amounts of aqueous body fluids and are further capable of holding these absorbed fluids under moderate pressures. These absorbent gelling materials can be dispersed homogeneously or homogeneously in a suitable carrier. Suitable carriers, provided that they are absorbent as such, may be used alone.

Suitable absorbent gelling materials for use herein most often comprise a substantially water-insoluble, slightly crosslinked, partially neutralized polymeric gelling material. This material forms a hydrogel upon contact with water. Such polymeric materials can be prepared from polymerizable, unsaturated, acid-containing monomers that are well known in the art.

Suitable carriers include materials that are traditionally used in absorbent structures such as, for example, natural, modified, or artificial. fibers, in particular treated or untreated cellulose fibers, in the form of fluff and / or tissue paper. Suitable carriers may be used together with the absorbent gelling material, but may also be used alone or in combination. In the context of sanitary napkins / panty liners, tissue paper or laminates thereof are most preferred.

One embodiment of the absorbent structure made according to the present invention comprises a double layer of tissue paper laminate formed by folding it on itself. These layers may be attached to each other. An absorbent gelling material may be included between the layers.

Treated cellulose fibers, such as stiffened cellulose fibers, may also be used. Synthetic fibers may also be used and include those made from cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylic resin (such as Orion), polyvinyl acetate, insoluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (such as nylon), polyesters, bicomponent fibers, triple component fibers, mixtures thereof, and the like. The fibrous surfaces are preferably hydrophilic or treated to be hydrophilic. The storage layer may also contain filler materials such as Perlite, diatomaceous earth, Vermiculite, and the like that improve fluid retention.

However, if the absorbent gelling material is dispersed heterogeneously in the carrier, the storage layer may, however, be locally homogeneous, i.e., have a distribution gradient in one or more directions within the dimensions of a particular storage layer. The inhomogeneous distribution may also refer to carrier laminates encapsulating partially or completely absorbent gelling materials.

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9,999,999,999 · 9,999,999 · ··· 999

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9999 99 99 9 · 99 99 (c) Optional fibrous (dusty) layer

The optional component to be included in the absorbent structure of the present invention is a fibrous layer adjacent to and typically lying below the storage layer. This backing fibrous layer is typically referred to as a dusting layer because it provides a substrate to which the absorbent gelling material is deposited in the storage layer during manufacture of the absorbent structure. Indeed, in those cases where the absorbent gelling material is in the form of macrostructures such as fibers, layers or strips, this fibrous dust layer need not be included. However, this dust layer provides some additional fluid management capacities such as rapid fluid leakage along the length of the pad.

(d) Other optional components of the absorbent structure

The absorbent structure of the present invention may comprise other optional components that are normally present in absorbent structures. For example, a reinforcing scrim may be located within or between the respective layers of the absorbent structure. These reinforcing scrims should be arranged so that they do not form obstacles at the interfaces for fluid transfer between surfaces. Assuming that structural integrity usually results from thermal bonding, these reinforcing scrims are not usually required for thermal bonded absorbent structures.

Another component that may be included in the absorbent structure of the present invention and is preferably provided at or as part of the primary or secondary fluid distribution layer is odor control means. Typically, an active carbon is incorporated in the absorbent structure, which is coated with or 99

9 9 9 9 9 · 9 9 9 9 · 9 9 9 9 9 9 9

999 99 99 * 99999 9 9 9 9 9 9 9

999 9 99 99 99 99 99 in addition to other odor control agents, especially suitable zeolite or clay materials. These components can be incorporated in any desired form, but are often included as fine, unobtrusive particles.

Preferred odor control systems for use herein comprise the following combinations: (i) silica, AGM, and zeolites preferably in a ratio of from 5: 1: 1 to 1: 1: 5, most preferably 3: 1: 1 to 1: 1: 3; (ii) zeolites, activated carbon and AGM; (iii) silica and AGM preferably in a ratio of from 5: 1 to 1: 5, preferably from 3: 1 to 1: 3; (iv) zeolites and AGM; (v) silica and zeolites, preferably in a ratio of from 1: 5 to 5: 1, more preferably from 1: 3 to 3: 1; (vi) chelating agents, especially ethylenediamine tetracetate and; (vii) chelating agents in conjunction with either odor control systems (i) to (v), preferably in a ratio of from 1:10 to 10: 1, preferably from 1: 5 to 5: 1, most preferably from 1: 3 to 3: 1.

According to the present invention, the amount of odor control system materials incorporated into an absorbent article can be readily determined by a person skilled in the art and also depends on the intended use of the absorbent article, bearing in mind the dimensions of the absorbent article. The absorbent article typically comprises a basis weight of said odor control system of from 5 gm ² to 400 gm ² , preferably from 100 gm ² to 300 gm ² , and most preferably from 150 gm ² to 250 gm ² . For example, the sanitary napkin or incontinence guard may contain 0.25 g to 5 g, preferably from 0.4 g to 3 g, most preferably from 0.5 g to 2.5 g of the compositions of this odor control system.

First, the backsheet prevents absorbed and retained exudates in the absorbent structure from wetting articles that contact the absorbent article such as panties, pajamas, trousers, and undergarments. This backsheet is preferably liquid impervious (e.g.

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It is preferably made of a thin plastic film, although other flexible and liquid impervious materials may also be used. As used herein, the term flexible refers to materials that are compliant and easily conform to the overall shape and contours of the human body. The backsheet may also have elastic characteristics allowing it to stretch elastically in one or two directions.

The backsheet typically extends across the entire absorbent structure and may also extend into and form a portion of the topsheet by folding around the absorbent structure. As a result, the topsheet arrangement as described in US 4,342,314, column 16, lines 4762 can be achieved without requiring selective topsheet perforation.

The backsheet may consist of a woven or nonwoven material, polymeric films such as thermoplastic films of polyethylene or polypropylene, or composite materials such as a film-coated nonwoven material. Preferably, the backsheet is a polyethylene film having a thickness of from about 0.012 mm (0.5 mils) to about 0.051 mm (2.0 inches).

Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio under the designation P18-O4O1, and Ethyl Corporation, Visqueen Division of Terre Haute, Indiana under the designation XP-39385. The backsheet is preferably embossed and / or finished with a matte surface to provide a more clothlike appearance.

The backsheet also preferably provides breathability to the absorbent article by being at least partially vapor permeable, preferably air permeable, but without impairing the main function of the backsheet itself. The backsheet may be a laminate material, for example, β

a combination of microporous film, nonwoven material and / or apertured formed film. The breathability, if desired, may be limited to the periphery of the backsheet or may be across the entire backsheet.

Suitable breathable backsheets for use herein may be selected from any of the breathable backsheets known in the art. There are basically two types of breathable backsheets, a single layer breathable backsheet that are breathable and impervious to liquids, and bottom layer laminates having at least two layers that provide both breathability and fluid impermeability in conjunction. The term "liquid impermeable" as used herein for breathable backsheets refers only to a barrier to fluid leakage from the article. In principle, however, this term does not intend to exclude the entry of fluid into the article through the breathable layer.

Suitable monolayer breathable backsheets for use herein include those described, for example, in GB A 2,184,389, GB A 2,184,390, GB A 2,184,391, US 4,591,523, US 3,989,867, US 3,156,242, and European Patent Application No. 95 120 653.1.

Suitable dual or multilayer breathable backsheets for use herein include those exemplified, for example, in US 3,881,489, US 4,341,216, US 4,713,068, US 4,818,600, EPO 203 821, EPO 710 471, EPO 710 472, European Patent Applications Nos. 95 120 647.3, 95 120 652.3, 95 120 653.1 and 96 830 097.0.

Particularly preferred are the lower layers meeting the requirements as defined in European Patent Application No. 96 830 343.8 and more preferably in which the absorbent article generally also meets the relevant requirements as described herein.

• • 0 0 0 0 0 β 0 β

External Connection Agents

The products of the present invention, as mentioned above, are applied directly to the wearer's skin. In particular, sanitary napkins are applied in the genital area of a typical female wearer, around the area of the fluid outlet. The word "skin of the present invention not only refers to the particular skin of the wearer, but also includes mucosal tissue as well as hair typically found in the genital area of sanitary napkin users.

In order to secure the article of the invention to the user ' s skin, it is necessary to provide an area on the side of the topsheet facing the wearer with an external attachment adhesive, also referred to as a body adhesive. .

In this regard, various embodiments are contemplated, but preferably, the body-facing adhesive is provided along the peripheral edge of the topsheet such that the central portion of the article is left free of adhesive. This most conveniently facilitates positioning of the article such that the adhesive-free liquid-permeable topsheet is disposed adjacent the body fluid outlet opening such that the effluent fluid is immediately transferred to the absorbent structure of the absorbent article, without the possibility of leakage or spillage.

However, it is not necessary for the body-facing adhesive to be provided in a closed circle around the periphery of the topsheet, but may be provided in additional areas such as dots or unobtrusive lines so that the bond between the various attachment points provides additional wearer comfort.

In order to meet the objectives of the present invention, the following should be considered.

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Physical, rheological and adhesion characteristics of body adhesive

Although body-facing adhesives are used as self-adhesive adhesives for the scalp of human skin and mucous tissue, it is understood that the body-adhesive compositions could hardly be regarded as typical self-adhesive adhesives (hereinafter referred to as "self-adhesive adhesives" PSA), based on the most characteristic Theological Behavior of these materials.

In fact, as adhesive specialists know, the most characteristic feature that distinguishes PSA from other substances that can temporarily adhere to things (as could, for example, water) is that their rheological parameters, and especially the elastic modulus of G ¹ , can broadly In addition, in particular G ¹ of PSA may increase by several orders of magnitude, while the frequency of applied loads varies from the typical frequency of the applied coupling loads to the typical ones. frequency of applied breaking loads, ie from 1 rad / sec to 100 rad / sec. as shown below.

As a first consequence, it is unacceptable to define the materials envisaged for use as an "adhesive" of parameters and by providing rheological values, in particular G ^1, at a fixed value of the applied load frequency. This can be misleading because, in the absence of other characteristics, it can lead to the inclusion of materials of no practical value. It is therefore considered that rheological characteristics must be based on dynamic considerations.

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This applies not only to the elastic modulus G ^1, but also for the modulus of viscosity G ¹¹ and hence also the value (mass peel "tan) (δ) = G ¹¹ ^ ^1. It is well known that typical PSAs (self-adhesive adhesives) do not only have a high variation of G ¹ over the applied load frequencies, but that there is also an even greater variation for G ¹¹ , which may approach or even exceed G ¹ , ie δ becomes about or even greater than 1, especially at the applied load frequencies that are typical for disconnection.

Without wishing to be bound by theory, this can be interpreted as an indication that a large fraction of the energy used for uncoupling is dissipated in internal frictions (so that it is not effective in causing uncoupling), although this causes macroscopically recording a high level of adhesive force .

As indicated above, the materials useful as body adhesives of the present invention have rheological characteristics that are measured at a reference temperature of 37 ° C, such as body temperature and within the frequency ranges of the applied loads. It has been found that upon application to the body-facing adhesive product, the adhesive contact is formed at a low frequency (frequency) of applied loads, while disengagement occurs at the rate of removal of the article. This rate is expressed as a frequency of applied loads of 100 rad / sec, while a low frequency of applied loads of adhesive bond forming was found to exist in the order of 1 rad / sec.

Further, it should be noted that G ¹ and G ¹¹ at an application rate of 1 rad / sec. are taken at 37 ° C. In practical use of the articles of the present invention, the actual storage temperature of the article and hence the temperature of the body-to-body adhesive in use varies widely. For example, storing in a hot bathroom next to a radiator could reach a temperature of up to about 37 ° C, while storing in a storage room or bathroom without heating, but with the window open, could approach 0 ° C during winter. However, since the product of the present invention is applied directly to the skin and a person skilled in the art is led to choose an adhesive composition having a low specific heat capacity (for example, preferably less than 4 J / g / K, more preferably less than 3 J (g / K, most preferably less than 2 J / g / K), the actual temperature of the body-to-body adhesive reaches very quickly 37, or the adhesive will even be heated by the wearer prior to application. Thus, it is believed that the adhesive bonding characteristics are selected most conveniently at body temperature.

In order to provide good bonding conditions, i.e. at load rates of about 1 rad / sec, the absolute values of the elastic modulus should not be too high, otherwise the adhesive is too hard and cannot fit tightly or form to the surface to which it is expected adhere. It is also important to have a low absolute value of G ^11, so that this adhesive had good cohesion which is particularly valuable for a direct application to the human body while the material remains soft and capable of adhering to the skin fine.

A value of 6 * 37 (1 rad / sec) over G ^II 37 (1 rad / sec) is important to ensure that the two values are aligned when the disposable absorbent article is applied to the skin. At the same time, absolute variations of G ^T 37 need to be limited within the range of considered load application frequencies. Therefore, the value of the ratio -G ^I 37 (ie G ^T 37 (100 rad / sec) - G ^I 37 (1 rad / sec)) over G ^II 37 (1 rad / sec) must be kept small in order to maintain securely attaching the disposable absorbent article to the wearer throughout the wearer, without causing the wearer &apos; s &apos;. ·· φ · ΦΦΦ φφ · · φφ φφ · φ discomfort during this time or when removing / delaminating the product. This can also be expressed in absolute terms by keeping -G ¹ 37 below certain values.

It's important to be

G ^T 37 (100 rad / sec) - G ^IZ 37 (100 rad / sec) ratio: ---------------------------- ------------- G ^I 37 (1 rad / sec) - G ^XI 37 (1 rad / sec) large enough to ensure that the dynamic behavior of both the modulus of elasticity is maintained, thus viscosity, in a relationship providing a secure adhesion during wear and a painless and easy removal at the end of the wear time.

Finally, the person skilled in the art will also recognize that the glass transition temperature Tg of the adhesive mixture, the specific heat capacity and the specific thermal conductivity are parameters that are useful to better define the completeness of the body adhesive useful materials.

The following set of characteristics should be met:

G ^T 37 (1 rad / sec) is in the range of 1500 Pa to 20,000 Pa, preferably 1500 Pa to 15,000 Pa, most preferably 3000 Pa to 10,000 Pa.

The ^GI 37 (1 rad / sec) is in the range 100 Pa to 15,000 Pa, preferably 100 Pa to 10,000 Pa, most preferably 300 Pa to 5,000 Pa.

The ratio G ^T 37 (1 rad / sec) / G ^r 37 (1 rad / sec) is in the range of 2 to 50, preferably 3 to 30.

ratio

G ^I 37 (100 rad / sec) G ^I 37 (1 rad / sec)

6 ^Ι]: 37 (100 rad / sec) G ^I1: 37 (1 rad / sec) «4 • · · · 4 · 4 · · 4 4 · · 4 4 · · I? 4 4 44 4 4 444 444

4444 is not less than 0.5, preferably in the range of 0.7 to 3, most preferably in the range of 1 to 1.8.

either the ratio of -G ^T 37/6 ^Σ 37 (1 rad / sec) is not more than 1,5, preferably not more than 1 and most preferably not more than 0,8, or -G ^T 37 not more than 10 000 Pa, preferably less than 5000 Pa, most preferably less than 2000 Pa, or both.

- The value of the ratio G ^T 37 / G ^I3: 37, at least for the frequency range of the applied loads from 1 to 100 rad / sec, should preferably be 2 or higher, more preferably 3.3 or higher, although nowhere in this frequency range 50, preferably 30.

- The rheological behavior can also be related to the glass transition temperature Tg. In the body adhesive of the present invention, the Tg should preferably be less than -15 ° C, more preferably less than -20 ° C, most preferably less than -25 ° C.

The rheological behavior and acceptance of any disposable article comprising an external adhesive may also be related to the specific heat capacity. The specific heat capacity of the external adhesive is less than 4 J / g / K, more preferably less than 3 J / g / K and most preferably less than 2 J / g / K.

The rheological behavior and acceptance of any disposable article comprising an external adhesive may also be related to the specific thermal conductivity. This specific ·

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The thermal conductivity is preferably greater than 0.1 W / m / K, preferably greater than 0.6 W / m / K and most preferably greater than 1 W / m / K.

Chemical and composition related to the characteristics of an adhesive for application to the body

In addition, the following composition measures can be used to provide body adhesive compositions that meet the above rheological and physical characteristics for the adhesive. It should be noted that most of the compositions useful as an adhesive for application to the body have a substantially gel-like structure and are preferably gels. This is derived from the fact that:

the predominant component is a softening agent which is a fluid at room temperature;

- macromolecular or polymeric component versus plasticizer is present in minor amounts. This creates, in preferred embodiments, a three dimensional network caused by physical or chemical linkages between molecules. Particularly useful bonds are those present in systems comprising block thermoplastic elastomers.

More specifically, such compositions typically include:

from 0.5 to 20%, preferably 5% to 15%, by weight of the macromolecular polymeric substance or a mixture of such substances soluble or swellable in the plasticizer composition (s) below. Because non-limiting examples of such macromolecular or polymeric 9 9 9 9 9 9 9 9

9 9 9 9 9 9 9 99 99 9 9 9

9 9 9 9 9 9 9 · 9 9 9 9 9 9 99 9 9 9 9 The substances may be natural and / or synthetic as natural gums or derivatives such as natural rubbers and gelatins, their derivatives and alginates; polyacrylic resins; polyvinyl alcohol; polyethylene oxide; polyvinylpyrrolidone (PVP) or polyvinyl ethers, their copolymers and derivatives; cellulose derivatives; thermoplastic elastomers of block polymers and preferably styrene block copolymers and more preferably the hydrogenated classes styrene / ethylene-butylene / styrene (SEBS), styrene / isoprene / styrene (SIS) and styrene / ethylene-propylene / styrene (SEPS);

from 51 to 99.5% by weight of the plasticizer or the plasticizer mixture, which are liquid at room temperature. Non-limiting examples of softening agents include water, various alcohols (such as glycerol in particular), glycols and their ethers, polyglycols, liquid polybutenes (or poly-butylenes), esters such as phthalates, adipates, stearates, palmitates, sebacates or myristates, natural or synthetic oils such as vegetable oils, mineral oils or combinations thereof;

from 0 to 600% by weight of the macromolecular polymeric tackifier resin, the main application of which is to adapt Tg especially in systems based on synthetic polymers;

from 0.5 to 10%, and more preferably from 0 to 5%, by weight of the substances to facilitate and stabilize the gel and gel-forming processes of both hydrophilic and hydrophobic emollients. These may be for oily systems, e.g., fatty acids, C ₈ to C ₂ 2r their metallic salts and their polyoxoderiváty; lanolin derivatives; silicon dioxide;

Flflflfl β; flentonite, montmorillonite and derivatives thereof; polyamides, waxes or mixtures thereof.

Conventional additives known in the art, such as preservatives, antioxidants, anti-UV agents, colorants, mineral fillers, rheology modifiers, etc., which may also be included in amounts up to 10% each.

When chemical cross-links are formed in a given system, the cross-linker may preferably be present in amounts up to 5% by weight. Chemical crosslinking can also be formed by neutralizing polymers having different functionalities as in the reaction between acidic polyacrylic resins and polysaccharides by mutual neutralization.

The resulting body adhesive compositions can be divided into three groups according to the nature of the main component, i.e., the liquid softener composition (s):

1) Hydrophobic compositions in which the emollient is typically an oil or a mixture of oils of vegetable or mineral origin and the polymer is usually a synthetic polymer, preferably an elastomer, soluble or swollen in the oil (s).

2) Mixed phase compositions in which both the hydrophobic and hydrophilic components, optionally both in the emollients and in the polymers, form two or more separate phases. In such cases, an emulsifier / active surfactant is preferably present at an appropriate level to form stable emulsions between said incompatible phases. It is preferred for the body-facing adhesives of the present invention that the hydrophobic components predominate over the hydrophilic components.

• ·

3) Hydrophilic compositions in which the plasticizer is typically water / glycerol / glycols and the like and / or mixtures thereof and the polymer phase is of synthetic (e.g., polyacrylic resin) or natural (e.g., natural gum) origin or mixtures thereof.

It will be appreciated that, contrary to what is already known in the medical art and the prior art cited, hydrophilic compositions (mixtures) are not preferred, while mixtures of hydrophobic and mixed phases 1 and 2) are preferred in the applications of the present invention.

This depends in part on technical reasons in the sense that many hydrophilic compositions used in the medical field exhibit too low elastic character and cohesion to be useful in the present invention. A second reason for favoring hydrophobic or mixed phase compositions is that the application of the present invention, particularly in the field of liners, will include the likelihood of adhesive to be applied to the body by liquid-absorbent liquid-contacting contacts.

Since these absorbent fluids are all of a generally aqueous type, contact with the hydrophilic body-facing adhesive would result in some absorption of body fluids into the body-facing adhesives.

This would then result in a change in the rheological characteristic and hence the appropriate functionality of the body-facing adhesive, causing an unhygienic appearance, but would also cause the body fluids to remain in direct contact with the skin for a longer period of time, which is typically not desirable no disposable absorbent articles. In addition, this may also create a potential unpleasant impact for the user, since some hydrophilic compositions are 9

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Another hydrophilic body adhesive also tends to be perceived to be cold and wet, so that the use of a fresh sanitary napkin or underarm sweat pad is not in accordance with typical consumer expectations. The additional problems result from the fact that in particular, body-facing adhesives containing water as a softening agent tend to dry out when not enclosed in an impermeable package.

The absorbent articles of the present invention may be manufactured by any of the methods known in the art. Applying adhesive to the topsheet side of the absorbent article should not cause greater problems to those skilled in the art, as this can be accomplished by techniques similar to those commonly used for adhesive fastening panties. The total area of the wearer facing surface of the absorbent article, which is coated with the body-facing adhesive, should be no more than 20%, preferably no more than 10%. The adhesive is preferably near the periphery of the absorbent article, and in the case of the film topsheets (or when the backsheet is folded over the topsheet), the adhesive is preferably on a non-liquid-permeable portion of the film.

The body adhesive on the article (as is common with pantie fastening adhesives) needs to be protected from use. This protection can be provided by a release liner such as a siliconized or surfactant-treated paper, provided that the paper is a good release surface for a specifically selected body adhesive.

In principle, the absorbent article of the invention is supported on the body of the wearer by an adhesive for adhering to the body and does not require additional support to remain in place. However, it is possible, for example, to provide a sanitary napkin with a slip resistant coating on the side of the backsheet, in order to prevent the sanitary napkin from progressively moving out of its location. Also, although pantie fastening adhesives are not desirable and are therefore not preferred according to the present invention, they are not strictly excluded in the context of the present invention.

EXAMPLE 1

An oil based composition useful for the sanitary napkins of the present invention was prepared, using 9.9% by weight of Kraton G-1651; a styrene / ethylene-butylene / styrene block copolymer containing 33% by weight of styrene is available from Shell Co .; and 59.3% by weight of Kaydol, a paraffinic mineral oil available from Witco Co.

In addition, the blend contained 301 parts of tack-increasing resin per 100 parts of Kraton polymer. The tackifying resin was Escorez 5300, a hydrogenated resin available from Exxon Co.

Magnesium stearate, available from Carío Erba S.p.A, was used as a cogelifying agent for the oil at 0.7% by weight.

An antioxidant from Ciba-Geigy, Irganox 1010 was added at 0.3 weight percent.

So in the end this composition has the following percentage:

Kraton ¹ G-1651 9, 9% weight, Kaydol 59.3% weight, Escorez 5300 29.8% weight, Stearan magnesium 0.7% weight, Irganox 1010 0.3% weight.

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This composition exhibited the following rheological properties at 37 ° C.

a) Modulus of elasticity at 1 rad / sec, G ^I 37 = 6,876 Pa.

b) Modulus of elasticity at 1 rad / sec, G ^II 37 = 550.5 Pa.

c) Ratio between modulus of elasticity and modulus of viscosity at 1 rad / sec, G ^T 37 / G ^IZ 37 = 12.49, ^{Σ Σ} 37 (100 rad / sec) - G ^{i: i} 37 (100 rad / sec. )

(d) ratio: ------------------------------------------ = 1,22

G ^I 37 (1 rad / sec) - G ^IT 37 (1 rad / sec)

e) The ratio of ^T -G 37 G divided by ^I 37 (1 rad / sec.) was 0.308, with -GM = 2124 Pa.

The above composition has been judged comfortable for application to sensitive, hairy skin.

COMPARATIVE EXAMPLE

The compound oil-based mixture was formulated using 7.1% by weight of Kraton G-1651; styrene / ethylene-butylene / styrene block copolymer containing 33% by weight of styrene and available from Shell Co .; and 41.9% by weight of Kaydol, a paraffin mineral oil available from Witco Co.

In addition, the blend contained 704 parts of tack-increasing resin per 100 parts of Kraton polymer. The tackifying resin was Regalrez 3102, a hydrocarbon resin available from Hercules Co.

Magnesium stearate, available from Carlo Erba S.p.A, was used as a cogelifying agent for the oil at 0.7% by weight.

φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ · φ φ φ φ φ φ φ φ φ φ

At a level of 0.3% by weight of Ciba-Geigy, Irganox 1010.

So in the end it has this content:

Kraton G-1651 Kaydol

Regalrez 3102 Magnesium stearate Irganox 1010

This composition exhibited properties.

was added antioxidant from the company composition following the percentage

7.1% by weight,

41.9% by weight,

50.0% by weight,

0,7% by weight,

0.3% by weight.

at 37 ° C following rheological

a) Modulus of elasticity at 1 rad / sec, G ^T 37 = 3 059 Pa.

b) Modulus of elasticity at 1 rad / sec, G ^{i: c} 37 = 1 208 Pa.

(c) Ratio between modulus of elasticity and modulus of viscosity at 1 rad / sec, G ^T 37 / G ^IX 37 = 2,53,

G ^x 37 (100 rad / sec) - G ^IT 37 (100 rad / sec)

(d) ratio: ------------------------------------------ = 2,87

G ^I 37 (1 rad / sec) - G ^IX 37 (1 rad / sec)

e) The ratio of -G ^T 37 over 6 ^τ 37 (1 rad / sec) was 3,944, with -G ^x 37 = 12,064.7 Pa.

The above composition has been judged to be very inconvenient for application to the skin of the forearm. Use on sensitive skin with hair was unacceptable.

Claims (10)

PATENT CLAIMS A disposable absorbent article for external adherence to a wearer having a wearer facing surface and a garment facing surface, and comprising an absorbent core between the wearer facing surface and the garment facing surface; characterized in that: - the article comprises at least a portion of the wearer facing surface of an adhesive for external adhesive attachment of the article, the adhesive having a modulus of elasticity at 37 ° C (100 ° Fahrenheit), G ^T 37, and a viscosity modulus at 37 ° C (100 ° Fahrenheit), G ^IX 37, the adhesive is selected to have an adhesive G ^I 37 (1 rad / sec.) In the range 1500 Pa to 20000 Pa, preferably 1500 Pa to 15000 Pa, most preferably 3000 Pa to 10000 Pa; GI ^{: t} 37 (1 rad / sec) in the range of 100 Pa to 15,000 Pa, preferably 100 Pa to 10,000 Pa, most preferably 300 Pa to 5,000 Pa; the ratio σ ^Σ 37 (1 rad / sec) / G ^TI 37 (1 rad / sec) is in the range of 2 to 50, preferably 3 to 30; G ^T 37 (100 rad / sec) - G ^IX 37 (100 rad / sec) ratio: --------------------------- -------------- G ^I 37 (1 rad / sec) - G ^{i: t} 37 (1 rad / sec) is not less than 0,5, preferably in the range 0,7 to 3, most preferably in the range of 1 to 1.8; ·· ·· ·· · • · »· · · 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 · 9 9 999 999 9 9 9 9 9 9999 99 99 99 99 99 ·· ···· alternatively either: -G ^I 37 (100 rad / sec.) - G ¹ (1 rad / sec.) Is not greater than 10000 Pa, preferably less than 5000 Pa, preferably less than 2000 Pa; or ratio -G ^of 37 (100 rad / sec) - G ^x 37 (1 rad / sec) G ^T 37 (1 rad / sec) is not more than 1.5, preferably not more than 1 and most preferably not more than 0.8, or a combination thereof. 2. A product according to claim 1, characterized in that the value of the ratio G ^I G divided by 37 ^Tl 37 in the frequency range of applied load from 1 to 100 rad / sec., It is in the range from 2 to 50, preferably 3.3 to 30. A disposable absorbent article according to any one of the preceding claims, wherein said adhesive is a mixture of materials comprising: from 51% to 99.5% by weight of a softening compound or mixture which is liquid at 20 ° C; from 0.5 to 20% by weight of a polymer compound or mixture that is soluble or swellable in said softening compound or mixture; attaching with an increasing resin in an amount of from 0% to 600% by weight of said polymer compound or mixture. * · ·· ♦ · 9 99 99 99 • 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9,999 9,999,999,999 9 9 9 9 9 9 9 9 99 · 99 99 99 99 99 4. An absorbent article according to claim 3 wherein: - said softening compound or mixture is selected from the group consisting of water, alcohols, glycols, oil or combinations thereof, and said polymer compound or mixture is selected from the group consisting of block copolymer thermoplastic elastomers, styrene block copolymers and hydrogenated styrene block copolymers. A disposable absorbent article according to any one of the preceding claims, wherein 80% by weight of said adhesive is comprised of hydrophobic components and most preferably all components of the adhesive are hydrophobic. A disposable absorbent article according to any of the preceding claims, wherein said adhesive has a glass transition temperature of less than -15 ° C, more preferably less than -20 ° C and most preferably less than -25 ° C. A disposable absorbent article according to any one of the preceding claims, wherein said adhesive has a specific heat capacity of less than 4 J / g / K, preferably less than 3 J / g / K and most preferably less than 2 J / g / K . A disposable absorbent article according to any one of the preceding claims, wherein said adhesive has a specific (specific) thermal conductivity greater than ♦ · · · · and 4 · · · · · · · I · 1 · · « 0.1 W / m / K, preferably greater than 0.6 W / m / K and most preferably greater than 1 W / m / K. A disposable absorbent article according to any preceding claim, wherein said adhesive covers less than 20%, preferably less than 10%, of the surface facing the wearer of the absorbent article. A disposable absorbent article according to any of the preceding claims, which is a sanitary napkin or panty cover.