FR2713478A1 - Absorbent article comprising a body adhesive for fixing it on the carrier. - Google Patents

Abstract

The article according to the invention comprises an absorbent (12) and, in the vicinity of said absorbent, an adhesive (14) enabling said absorbent to be fixed on the trunk of the wearer, said article having a total weight greater than approximately 5 grams.

Description

The present invention relates to disposable absorbent articles, and

  particularly absorbent articles adapted to be self-supporting and fixed on the user. More particularly, the present invention relates to sanitary napkins for intimate feminine hygiene which

  can be fixed on the body of the user.

  A wide variety of absorbent articles designed for the absorption of body fluids such as menses, urine and faeces are well known. When it comes to female protective devices, there are two basic types: sanitary napkins and tampons. Sanitary napkins, which in the context of this

  description include thin devices such as

  panty liners and interlabial pads, have been developed for external use in the vicinity of the female intimate area, while tampons have been developed for internal use in the vaginal cavity to interrupt menstrual flow which comes from it. Each of

  these types of products have distinct advantages.

  A tampon is made from a natural absorbent material such as cotton, from synthetic materials such as polyethylene or rayon, or from a combination of such materials. Because the tampon is hidden and does not reveal that the woman is menstruating, it is aesthetically preferable to a sanitary napkin. However, its use is prohibited in a number of situations: in some women, the use of a tampon is uncomfortable; its use is not acceptable immediately after birth or during post-surgical periods or when there is a medical condition; finally, when the menstrual flow is very abundant, the tampon can have an insufficient capacity to absorb secretions, which makes the towel

  hygienic necessary to complete or replace the tampon.

  With regard to sanitary napkins, an important objective is to control the absorption and flow of exudate or body fluids in a manner which results in maximum use of the absorbent available. Ideally, a sanitary napkin is expected to immediately accept all of the received body fluid, transport it quickly away from the receiving point, and keep the transported fluid within the boundaries of the napkin, while now

  the surface in contact with the body as dry as possible.

  The prior art describes many sanitary napkins which have aimed to meet one or more of the above expectations. Improvements in the absorbency of sanitary napkins have included, inter alia, the addition of superabsorbents to the absorbent pad and various methods of improving contact with the body. With regard to this last point, there are at least three general paths. One way is to give the towel a cup or boat shape that aims to collect menses

  as soon as they come out of the vaginal opening.

  Another way relates to sanitary napkins which have an elevation or a bump in their middle part so as to be close to, or in contact with, the intimate region when they are worn. The purpose of these sanitary napkins is to come into contact with the menses and to absorb them as soon as they leave the vestibule. Such bumps or raised areas have been formed by incorporating an additional middle absorbent or

  deformation element resistant to bending.

  The third way is that of sanitary napkins which are not predisposed to have a depression or hump shape when worn, but which have rather

  more or less in rope form when worn.

  Such sanitary napkins usually have an absorbent core of down pulp surrounded by flexible outer casings. The attachment of a sanitary napkin during use is generally achieved by attaching the sanitary napkin to the wearer's undergarment using a pressure sensitive adhesive. The prior art also teaches the use of fins or flaps which fold around the elastic edges of the crotch portion of an undergarment and which can then be fixed under this part using an adhesive. The prior art further teaches the use of panels having

mechanical fasteners.

  These methods of attaching a sanitary napkin to an undergarment can have a number of drawbacks. One drawback is that the adhesive can stick to the inside of the undergarment and cause the color of the undergarment to change. Another disadvantage is that the towel tends to move with the undergarment rather than with the wearer's body. This can result in less safe adaptation and greater occurrence of fluid leakage, irritation and

friction.

  It has now been invented a sanitary napkin having a body adhesive which improves the adaptation to the curve of the human body, is comfortable to wear and is

  effective in preventing fluid leakage.

  Briefly, the present invention relates to a disposable absorbent article having a total weight greater than about grams and adapted to be attached to the trunk of a human in the intimate region. The absorbent article includes a

  absorbent and a body side adhesive joined to the absorbent.

  Absorbent materials are designed to absorb body exudates, including menstrual fluids, catamenial fluids, blood and urine. The body side adhesives used according to the invention are of the type which offers suitable adhesion properties with respect to the skin but which can be removed without significant discomfort. The purpose of the adhesive is to fix the absorbent on the carrier, improving the contact between the body and the article. The adhesives generally have a peel strength of between about 25 and about 700 g. Because the absorbent articles are in intimate contact with the carrier, it is advantageous that the surface of the absorbent, distal to the carrier, is impermeable to liquids. Impermeability to liquids can be obtained by means well known in the art and these means include fixing a thin polyethylene support sheet to the absorbent or coating the absorbent fibers with a hydrophobic material. The main object of the invention is to provide an absorbent article, such as a sanitary napkin, a disposable diaper, an incontinent pad, and the like.

  is adhesively attached to the wearer's body.

  Another object of the present invention is to provide a thin and flexible absorbent article which, by the simple fact of placing it on the body of the wearer, conforms and adapts

  closely to the external body surfaces.

  Yet another object of the invention is to provide an absorbent article which remedies the use of friction support means, which results in an article

  absorbent conforming to the body more comfortably.

  Another object of the present invention is to provide a sanitary napkin which uses an adhesive applied to the body side surface of said napkin to fix it.

on the user.

  Yet another object of the present invention is to provide a sanitary napkin which, when attached to the body of the user is, practically speaking, invisible as to its contours under clothing

of the user.

  These and other objects of the invention will become more apparent

  clearly on reading the description below made in

  reference to the accompanying drawings in which: - Figure 1 is a perspective view of an absorbent article having a body adhesive disposed in the vicinity of its periphery and having a removable element on the body side partially turned up; - Figure 2 is a perspective view of another embodiment of the absorbent article, showing an opening centered longitudinally and transversely provided through the upper sheet and the absorbent; - Figure 3 is a cross-sectional view taken along line 3-3 of Figure 2; - Figure 4 is a top view of another embodiment of the absorbent article having an upper surface which is at least partially covered with a support sheet; - Figure 5 is a cross-sectional view taken along line 5-5 of Figure 4 showing the adhesive located partly on the top sheet and partly on the backing sheet; Figure 6 is a sectional view of an alternative embodiment of the absorbent article of Figure 5, taken along line 5-5, showing the carrier sheet extending over the periphery of the absorbent and l adhesive completely disposed on the support sheet; - Figure 7 is a top view of another embodiment showing an opening in the top sheet and having a flattened front portion and a rear portion having an edge or a peak; - Figure 8 is a side view of the article of Figure 7 showing the flattened front portion and the raised rear portion. Body adhesive is shown around

from the periphery of the absorbent.

  The present invention generally relates to disposable absorbent articles having a total weight greater than about 5 grams which are attached to the body of a

  user with pressure sensitive body adhesive.

  For convenience of description, the invention will be described

  as applied to a catamenial device, that is to say to a sanitary napkin, without being limited to this application. It should be understood that the invention can be adapted to other absorbent articles such as diapers,

  devices for incontinents, and the like.

  For ease of understanding, when referring to the figures, the same references designate the same parts in the different views and embodiments. If we refer to Figure 1, we see an embodiment

sanitary napkin 10.

  In the basic embodiment, the sanitary napkin 10 includes an absorbent 12 and a body side adhesive 14 disposed toward the wearer's body and joined to the absorbent 12. The adhesive 14 secures the napkin

  hygienic 10 on the wearer's body.

  As used herein, the term "sanitary napkin" refers to an article which is worn by women in the vicinity of the intimate region and which is designed to absorb and retain various exudates which are delivered by the body, such as blood , menses and urine, and which are intended for

  be discarded after a single use.

  Interlabial devices which are housed partially inside and partially outside the vestibule of the women who wear them, also fall within

the scope of the invention.

  The sanitary napkin 10 preferably has a total weight of less than about 12 grams. The sanitary napkin has an oval shape but it could have an hourglass shape, a race track shape or any other shape that allows the absorbent article to come into intimate contact with the wearer. The sanitary napkin 10 has a body side surface 15 which may include a liquid permeable top sheet 16 in the vicinity of the wearer's body; a liquid impermeable sheet, or barrier, 18 which is distal of the wearer's body; an absorbent 12 disposed between the upper sheet 16 and the support sheet 18; and an adhesive 14 on the body side, pressure sensitive and joined to the surface on the body side 15. The adhesive 14 fixes the sanitary napkin 10 to the body of the user. In general, the sanitary napkin 10 is provided with a separable element 20 which is a material fixed in a removable manner to protect the adhesive 14 from contamination and which advantageously protects the upper sheet 16 from contamination before laying, until the element 20 is removed and sanitary napkin 10

  is properly positioned for use.

  Referring to Figures 2 and 3, it can be seen that the sanitary napkin 10 'has an upper sheet 16 and a support sheet 18 generally having longitudinal and transverse dimensions greater than those of the absorbent 12 so that they extend beyond the outer perimeter 22 of the absorbent 12 to form a peripheral edge 24. The support sheet 18 is coextensive and in contact relation, face to face, with the upper sheet 16, and it has a surface 26 facing the absorbent 16 and disposed under the latter. The upper sheet 16 and the support sheet 18 are sealed together from the perimeter 22 of the absorbent to the peripheral edge 24 in any suitable manner which does not leave hard and uncomfortable residues annoying for the user. As used herein, the term "sealed" refers to configurations in which a first element is joined directly to a second element and to configurations in which a first element is joined indirectly to a second element by fixing the first element to intermediate elements which, in turn, are attached to the second element. Fastening means are well known to those skilled in the art and they include the use of fusible adhesives in a uniform and continuous layer, adhesive traces, pressure-sensitive adhesives, double-sided tape. , link

  ultrasonic, and thermal bonding.

  The absorbent 12 has a first surface 28 and a second surface 30. The first surface 28 is disposed in the direction of the top sheet 16 and the second surface 30 is disposed in the direction of the support sheet 18. The absorbent article may also include a drainage layer 32. The drainage layer 32 is arranged in the vicinity of the second surface 30. The role of the drainage layer 32 is to direct the bodily fluid which comes into contact with the upper sheet 16 as far as the absorbent 12 The drainage layer 32 may include more than one material having

drainage characteristics.

  The first and second surfaces, respectively 28 and, of the absorbent 12 have openings coaxially

  aligned through them and together forming the opening 34.

  Although this is not an essential feature, the opening 34 may affect the upper sheet 16 so that the bodily fluid will not have to pass through the upper sheet 16 before coming into contact with the absorbent 12. Preferably, the opening 34 affects the drainage layer 32. This arrangement allows the opening 34 to act as a conduit for rapidly transporting any sudden outflow of body fluid away from the point of reception to the second surface 30 of the absorbent which is arranged on the other side of the absorbent 12. This also allows the upper sheet 16, the absorbent 12, and the support sheet 18 to act as a surrounding reservoir and retaining the delivered body fluid until it is absorbed by the absorbent 12. The support sheet 18 can have between approximately 5% and approximately 95% of its surface 26 linked to the adjacent layer 32. Better still, the sheet

  support 18 is joined marginally to the adjacent layer 32.

  As shown in Figures 1 to 3, the body adhesive 14 is disposed inside with respect to the peripheral edge 24 of the sanitary napkin 10 and 10 '. The role of the adhesive 14 is to fix the sanitary napkin 10 and 10 'on the body of the user. As illustrated in Figure 3, the adhesive 14 is adjacent to the top sheet 16 and it covers the perimeter 22, but it could be placed at a distance of up to about 3 centimeters from the perimeter 22 of the absorbent 12. Although the adhesive 14 is shown as a uniform continuous layer, it is understood that those skilled in the art can easily select a different route for fixing by adhesive. For example,

  an intermittent trace of adhesive 14 can be applied.

  The adhesive 14 is applied to less than about 85% of the body side area 15 of the sanitary napkin 10, better to less than about 50% and even better to less than about%. The adhesive 14 is usually covered, before the sanitary napkin 10 is fixed on the user, by a separable element 20. The separable element 20 serves to protect the adhesive 14 against sticking against exterior surfaces before use and to prevent contamination of the adhesive 14. Advantageously, the element 20 also prevents the top sheet 16 from being prematurely soiled before laying on the body of the user. Suitable wrap materials can be any material capable of being releasably attached to the adhesive 24 and they include the materials commonly used to protect the garment fastening adhesives currently used on commercially available sanitary napkins . Non-limiting examples include Kraft paper coated with silicone, SILOX El-0 and BL30MG-A

  SILOX 4 / P0 manufactured by Akrosil Corporation.

  The liquid permeable top sheet 16 is designed to come into contact with the wearer's body and may be made of a woven or non-woven material, natural or synthetic, which is easily penetrated by body fluid. Suitable materials include the bonded webs of polyester, polypropylene, polyethylene, nylon and other thermally bondable fibers. Other polyolefins, such as copolymers of polypropylene and polyethylene, linear low density polyethylene, thinly perforated film webs and mesh materials also work well. Particularly preferred are composite materials formed from a polymer and a nonwoven fabric material. The composite sheets are generally produced by extruding the polymer onto a sheet of material linked to the spinning to form a sheet in one piece. This material is preferred because the surface of the outer fabric is not irritating to the skin of a wearer. Yet another material suitable for producing the upper sheet 16 is a sheet linked to the spinning of polypropylene. The tablecloth can contain from about 1% to about 6% of titanium dioxide as a pigment to give a white and clean appearance. It is desirable to use a uniform material bonded to the spinning because it has sufficient strength, after being perforated in the longitudinal direction, to resist twisting or separation during use. The most preferred polypropylene webs have a weight of between about 18 and 40 g / m2. Optimal weight is between

about 30 and 40 g / m2.

  The top sheet 16 can also be treated with a surfactant to improve its hydrophilic characteristics and thus facilitate absorption of the liquid. The surfactant can be included by topical addition or it can be internally applied materials, such as polysiloxanes. The support sheet 18 can allow the passage of air or steam out of the sanitary napkin 10 while blocking the passage of body fluids and liquids from the absorbent 12. A good material is a micro-embossed polymer film such as than polyethylene or polypropylene. Two-component films can also be used as well as woven and non-woven fabrics which have been treated to make them impermeable to liquids. The support sheet 18 can be made of a polyethylene film. More preferably, the support sheet 18 is made of a polyethylene film having a thickness in the range of from about 0.012 mm to about 1.0 mm. The support sheet 18 must be soft and flexible. As used herein, the term "flexible" refers to materials which readily conform to shape and

  general external contours of the human anatomy.

  In a preferred embodiment of the present invention, the backing sheet 18, instead of being attached to the top sheet 16 as described above, may have from about 5% to about 95% of the surface 26 disposed under the absorbent 12 fixed to the adjacent layer 32. Preferably, less than approximately 50% of the surface 26 are fixed, and better still, less than approximately 20%. More preferably, the surface 26 is fixed only marginally to the adjacent layer 32. This arrangement allows the support sheet 18 to move away from the absorbent 12 by distending downward, thus acting in the manner of a fluid reservoir to retain spills

sudden body fluid.

  The upper sheet 16 and the support sheet 18 enclose, in combination, the absorbent 12, substantially defining the perimeter 22 of the absorbent. The absorbent materials used in absorbent article 10 are designed to absorb body exudates, including menstrual fluids, catamenial fluids, blood and urine. Suitable materials include wood pulp down, rayon, cotton, meltblown polymers, such as polyester, polypropylene and coforms. A co-formed is an air formed combination of meltblown polymers such as polypropylene and individual absorbent free fibers such as cellulose. A preferred material is wood fluff because it is low cost and relatively easy to form and has good absorbency. The absorbent 12 can be a composite made of a hydrophilic material which can be formed from various natural or synthetic fibers, wood pulp fibers, regenerated cotton or cellulose fibers, an air-spread fabric or a mixture of pulp and other fibers. Absorbent 12 can be made from other well known materials used in absorbent articles, including multiple layers of cellulose wadding, rayon fibers, cellulose sponge, hydrophilic synthetic sponge, such as polyurethane, and the like. The absorbent 12 can have various densities in the direction Z. By "direction Z" is meant the direction of the thickness of the sanitary napkin where the directions X and Y would be respectively the longitudinal and transverse directions of the sanitary napkin 10, see Figure 2. Preferably, the first surface 28 of the absorbent 12 has a lower density than the second surface 30. This helps to attract any bodily fluid towards the support sheet 18 and to reduce and / or prevent the fluid to go back towards

  the user, a phenomenon known as "rewetting".

  Although the sanitary napkin 10 is described as having a single layer of absorbent material forming the absorbent 12, the absorbent 12 could include more than one layer of absorbent material. As viewed from the bottom sheet 16 downwards towards the support sheet 18, each successive absorbent layer, if several are used, preferably has a density and a liquid absorption capacity greater than those of the absorbent layer previous. It should be emphasized that the values for absorbency are relative for any particular style of absorbent article. It is therefore entirely possible that a particular style of absorbent article could use the same material in its second absorbent layer as that used as the first absorbent layer.

in another type of article.

  Absorbent 12 may contain superabsorbent particles which are extremely effective in retaining body fluids. Superabsorbents are capable of absorbing a large amount of fluid relative to their own weight. Typical superabsorbents used in absorbent articles, such as sanitary napkins, can absorb from about 5 to about 60 times their own weight of body fluids. However, the absorption mechanism of superabsorbents is usually slower than the rate of absorption of fluids by the

cellulose down.

  It has been found that superabsorbents have great mechanical stability in the inflated state, a capacity to rapidly absorb fluids, and those which have a strong capacity for binding with respect to fluids fulfill their role in catamenial devices. . Hydroxy-functional polymers have been found to be good superabsorbents for this application. The superabsorbent can be a polymer composition forming a hydrogel, which composition is water-insoluble, slightly crosslinked and partially neutralized. Such superabsorbents can be obtained from Dow Chemical, Hoechst-Celanese, and Stockhausen, Inc. The sanitary napkin 10 and 10 'may contain a drainage layer 32. The drainage layer 32 is disposed in the vicinity of the second surface 30 of the absorbent 12. The role of the drainage layer 32 is to distribute the bodily fluid towards, and from one side to the other, of the second surface of the absorbent 12. Thus, any material having sufficient capillary activity , or any other means of attracting and transporting the bodily fluid coming into intimate contact with its surface, and thus distributing the liquid spills from one side to the other of all the absorbent 12 can be used. The drainage layer 32 can be made of a fibrous material having a low absorption capacity. Suitable materials include blends of polyester and rayon with minimal fluid retention capacity. Other materials can be sheets formed in the air or carded of polyester, rayon or polypropylene. A preferred material for drainage layer 32 is a meltblown polypropylene layer having a thickness of about 0.6 mm, a weight of about 60 g / m2, a pore size of about 10.6 pm, and an average fiber diameter of about 3.9 gm. The drainage layer 32 can be coextensive with the second surface 30 of the absorbent 12. Preferably, it is of a size smaller than that of the absorbent 12, thus having a peripheral edge 36 situated inside with respect to at the outer perimeter 22 of the absorbent 12. The drainage layer 32 can have a thickness ranging from approximately 10 mm to approximately 65 mm and a length ranging from approximately 5 mm to approximately mm. The drainage layer 32 can have a drainage speed equal to the drainage speed of the second surface

  30 of the absorbent 12 to facilitate the transport of liquid.

  Preferably, the drainage layer 32 has a drainage speed greater than that of the second surface 30. The drainage speeds can be determined by following the procedure described in US-A-4 256 111 issued in the name of

Lassen, March 17, 1981.

  The sanitary napkins 10 and 10 'are provided with a side-body adhesive similar to that described above for retaining the sanitary napkin 10 and 10' against the vulva of the user so that only the napkin 10 'will be described. in detail. The side surface

  body 15 is coated with an adhesive 14 on the body side.

  The adhesive 14 is generally placed in an area of approximately 3 cm from the periphery 22 of the absorbent 12, including the outer perimeter 22 thereof. The adhesive 14 can be applied in the form of a continuous or intermittent line. The thickness and surface of the adhesive 14 can also vary. The adhesive 14 should be superimposed on less than about 85% of the body side surface 15 of the sanitary napkin 10 ', preferably on less than about 50%, and more preferably on less than about 25%. Non-limiting factors that affect the adhesion of the sanitary napkin 10 'to the wearer include: the strength of the adhesive 14; the location of the adhesive 14 on the sanitary napkin 10 '; whether the adhesive 14 will come into contact with the wearer's skin or be mainly mixed with body hair; and the size, weight and shape of the sanitary napkin 10 '. Consequently, the adhesives used according to the invention can have an adequate adhesive force to retain the sanitary napkin 10 'against the user under static and dynamic conditions, but they must be able to be separated from the skin and the hairs without causing strong degree of discomfort. In a preferred embodiment, the sanitary napkin 10 'has a total weight of between about 5 g and less than about 12 g. The term "total weight" as used herein means the weight of the sanitary napkin 10 'without a separable member 20 and before it has received any application of fluid. Additives suitable for use have been found to have an adhesive peel strength, as determined by the modified Pressure Sensitive Tape Council peel strength test (PSTC-1) described below of about 25 g to about 700 g. The peel strength is preferably between about 100 g and about 650 g, more preferably from about 100 g to about 450 g, and even more preferably from about 100 g to about 400 g. PSTC-1 is a standardized test procedure which is described in more detail on page 23 of the tenth edition of Test Methods copyright 1992, available from Pressure Sensitive Tape Council, 401 North Michigan Avenue, Chicago,

Illinois 60611-4267 (USA).

  In addition, suitable additives have rheological properties, namely a loss modulus (G "), a storage modulus (G ') and a loss angle tangent (tan 6) falling within the ranges indicated in the Table 1 below. The terms "loss angle tangent (tan 6 or G" / G ') and "storage module" (G') are defined according to the established principles of dynamic mechanics. These rheological quantities are measured on samples of loose adhesive not suspended on any substrate and having a thickness of approximately 0.56 mm The adhesive is cut in a 25 cm circle and placed between two parallel 25 cm fixing plates belonging a Rheometrics Dynamic Spectrometer (RDS), which can be obtained from Rheometrics, 1 Possum Town Road, Piscataway, New Jersey 08854 (USA). The top plate is lowered over the sample until a measuring device of normal strength indicates slight deformation. s samples equilibrate at the test temperature (for example 25 C and 37 C) before the test. A mini-computer controls the application of a 5% peak-to-peak shear force to the sample. The frequency of the application can be controlled to a fraction of radiant / second (a radian is equal to 6.28 Hz). The values of the complex modules (G *) and of the tangent of loss angle (tan 6) are calculated by the computer from geometric factors, the peak-to-peak amplitude of the torque signal and the delay of the torque output wave. The definition of the loss angle tangent (tan 6) and the relationship between G *, G 'and G "provide two equations with two unknowns which can be solved by the computer to obtain G" and G' because G * and the loss angle tangent (tan 6) are both known values calculated as indicated above. For any of these values, the

  frequency is 10 radians / second.

TABLE 1

  Properties Values in 104 dynes / cm2

at 25 C-370C

  Loss module (G ") 0.5 to 20 Storage module (G ') 0.2 to 45 Loss angle tangent (tan 6 = G" / G') 0.1 to 1.0 Examples not Examples of suitable adhesives include a hydrogel, hydrophilic, pressure sensitive adhesive material. Such hydrogel adhesives are marketed by Promeon Division of Medtronic, Inc., Minneapolis, Minnesota (USA), under the brand "PROMEON" and they include a commercially available medical grade hydrogel.

  marketed under the name PROMEON RG-63B. A description

  detailed description of such a hydrogel composition is given in US-A-4,593,053, issued in the name of Jevne et al., on June 3, 1986. Another suitable hydrogel is described in US-A-4,699,146, issued on behalf of Sieverding, October 13, 1987. The strength required to peel the adhesive is determined by a test which is modeled according to the PSTC-1 90 Adhesive Peel Test Procedure, a procedure which has been modified as below. The Adhesive Peel Test Procedure gives a force value in relation to a unidirectional removal force from a subject's forearm.

APPARATUS

  The device used for the adhesive peel test is an Instron model 4201 material testing instrument or an equivalent instrument. This instrument is available from Instron Engineering Corporation, Canton, Massachusetts

(USA).

PREPARATION OF TESTS

  To carry out the procedure, as explained below, at least 5 test tubes must be prepared. The test pieces were approximately 0.635 cm (1/4 inch) wide, with the spacing between test pieces not greater than about 0.04 cm (1 / 64th of an inch). The test pieces were approximately 15.24 cm (6 inches) long. In the case where a non-hydrogel adhesive is tested, it is conditioned by placing the strips of adhesive laminate at a temperature of 22.8 + 1.1 C (73 + 2 F) and at a relative humidity of + 2% for 24 hours. The refractory strip at bonding

  is not removed from the adhesive strips.

  In case the adhesive is a hydrogel, it is tested

  at residual moisture contents of 25%, 35% and 45%.

  In preparing the hydrogel samples for testing, all samples were conditioned to have

the appropriate moisture content.

  Samples with a moisture content of 25% were prepared by placing the hydrogel having a thickness of + 1 mm on a nonwoven substrate. These laminates were placed in an oven at 54.4 + 1.1 C (130 + 2 F), the adhesives being exposed. After 45 minutes, the bonding refractory lining is put back on the samples, after which they are sealed in a polyethylene bag. The samples having a moisture content of 35% were prepared by placing the adhesive hydrogel laminates having a thickness of 15 + 1 mm on a nonwoven substrate. The laminates were then placed in a chamber having a temperature of 22.8 + 1.1 C (73 2 F) and a relative humidity of 50 + 2% for 6 hours. The samples were then removed from the chamber and the bonding refractory lining was put back on the samples which were then sealed in

a poly bag.

  Samples with 45% hydration were prepared by placing the adhesive hydrogel laminates having a thickness of 15 + 1 mm on a nonwoven substrate. The laminates were placed in a chamber at a temperature of 37.8 1.1 C (100 + 20F) and a relative humidity of + 2% for 6 hours. The samples were then removed from the chamber and the bonding liner was put back on the samples, after which they were sealed in a polyethylene bag. The hydration percentage is determined by evaporating the moisture from the adhesive laminate at 112 C (234 F) for 8 to 12 hours. Hydration was determined by weight differences, i.e. the weight of the nonwoven substrate was subtracted from the weight of the samples, after which the weight of the sample from which the moisture was evaporated

  was divided by the original weight of the hydrogel adhesive.

OPERATING MODE

  The procedure for the Adhesive Peeling Test Procedure is as follows: the test pieces are tested in a room having a temperature of 22.8 1.7 C (73 3 F) and a relative humidity of 50 + 2%. Since the adhesive is intended to fix an absorbent article on the body of a wearer, the adhesion is tested on human arms. Fix one end of the 15.24 cm test piece on the forearm and

  spread the test tube along the length of the arm.

  Pass a 2.043 kg (4.5 pound) roll at a speed of approximately 0.3048 m / min (once across the length of the test tube and once across the width) 12 inch / min). After 5 minutes, peel back the free end of the specimen at an angle of 90 over a length of

  2.54 cm (1 inch) of test tube from the subject's forearm.

  Tighten the end of the specimen that has been turned back into the movable jaw of the adhesion tester, allowing the subject's forearm to rest on the fixed part of the tester. Operate the movable jaw at a speed of 5.08 and 10.16 m / min (200 and 400 inches / min). Once the movable jaw has started to move, ignore the values obtained during the first 2.54 cm of strip removed. Use the average peel value obtained during the next 5.08 cm (2 inches) of removal as the adhesion value. The above steps are repeated until at least 5 similar test pieces have been tested. 5 CALCULATIONS

  The peel test for each specimen is the average force read for the specimen in question.

  EXAMPLE 1 (Comparative Example) The rheological data of an adhesive which is considered too aggressive to be used, but which can be used in the case of a dressing adhesive, is "DURO-TAKR 9908" available from National. Starch and Chemical Company, 10 Finderne Avenue, PO Box 6500, Bridgewater, New Jersey 08807-3300 (USA). The test piece was prepared using the procedure described above to determine the rheological data. The

  results are listed in Table 2 below.

TABLE 2

  Values in 104 dynes / cm2 Properties at 25 C-37 C with a frequency of 10 radians / second

250C 370C

  Loss module (G ") 31 16 Storage module (G ') 62 52 Loss angle tangent (tan ô) 0.46 0.32

EXAMPLE 2

  Following the above procedures, a number of peel resistance test specimens were used using PROMEON as an adhesive.

hydrogel RG 63B.

  The results are reported in Table 3. The rheological data of the hydrogel are listed in Table 4. All values are expressed in

  (104) dynes / cm2 and the frequency is 10 radians / second.

TABLE 3

  Peel resistance at 90 Hydration Speed time Number Average contact range cm / min of peel tests (inches / min) (grams) (grams) 25% 5 min 508 (200) 45 31-402 164 min 1016 (400) 44 58-405 190% 5 min 508 (200) 46 83-601 236 min 1016 (400) 46 81-628 268 44% 5 min 508 (200) 46 57-386 169 min 1016 (400) 46 70-511 218

TABLE 4

Properties Water content

% 35% 45%

  Loss module (G ") at 25 C 21 4.2 0.76 Storage module (G ') at 25 C 37 7.5 1.5 Loss module (tan 6) 0.63 0.55 0.47 Loss module (G ") at 37 C 14 3.4 0.92 Storage module (G ') at 37 C 24 6.3 2.0 Loss module (tan 6) 0.59 0.55 0.47 Referring to Figures 4 to 6, there is shown another embodiment of a sanitary napkin 10 ". The sanitary napkin 10" has a surface on the body side 15, a backing sheet 18, an absorbent 12 and a drainage layer 22. The absorbent 12 is advantageously provided with an opening 34 extending through the first and second surfaces, respectively 28 and 30, of the absorbent 12. The surface on the body side 15 of the sanitary napkin 10 " includes liquid permeable top sheet 16 and a portion

of the support sheet 18.

  The opening 34 can have a variety of geometric configurations. The openings together constituting the opening 34 are aligned coaxially and affect the upper sheet 16 and preferably the drainage layer 32. The opening can have a substantially symmetrical shape and it can be positioned along the longitudinal axis X-X. Preferably, the opening 34 is centered longitudinally and transversely along the axes XX and YY, see FIG. 4. The opening 34 allows the sanitary napkin 10 "to more fully receive the menses, sometimes very viscous, by allowing the support sheet 18 to accumulate excess menstruation away from the upper sheet 16 and in the vicinity of the second surface of the absorbent 12. Without the opening 34, the absorption of exudates may be less and the exudates Unabsorbed may remain in contact with the body causing irritation or may extend beyond the peripheral edge 24 of the 10 "sanitary napkin and cause soiling. The opening 34 preferably has a relatively large area to be in contact with the menses as they exit the wearer's vagina without, however, being large enough to come into contact with the surrounding areas of skin which could be soiled or irritated. by rewetting. The opening 34 must be positioned on the body so that the menses come into contact with said opening 34 before coming

  in contact with the rest of the top sheet 16.

  In dimensional terms, the opening 34 has a size between about 10 mm and about 65 mm. In the case of an elliptical or similar shape having unequal dimensions, the opening 34 may have a minor axis comprised between approximately mm and approximately 35 mm and a major axis comprised between approximately mm and approximately 85 mm and be suitably positioned on

sanitary napkin 10.

  If we now refer to Figure 5, we see a cross-sectional view of Figure 4 taken along the transverse axis Y-Y. In the formation of the body side surface 15, the support sheet 18 partially envelops the upper sheet 16. The support sheet 18 can extend above the upper sheet 16, inwards from the outer peripheral edge 24 of the towel. hygienic 10 ", over a distance between

about 0.1 mm and about 30 mm.

  Figure 6 shows a cross-sectional view taken along the Y-Y axis of another embodiment of the

  10 "sanitary napkin, as shown in Figure 4.

  The difference between the embodiments illustrated in FIGS. 5 and 6 is that, in FIG. 6, the support sheet 18 extends over the upper sheet 16 for a sufficient distance to allow the adhesive 14 to be placed on

  the support sheet 18 which is in the vicinity of the user.

  The backing sheet 18 can extend over the top sheet 16 sufficiently to allow the adhesive 14 to be joined entirely to the backing sheet 18 turned towards the trunk of the user and inside with respect at the perimeter 22. The support sheet 18 can be fixed to the upper sheet 16 by means well known to those skilled in the art, such as bands spaced apart

  another construction adhesive.

  If we refer to Figures 7 and 8, we see another embodiment of a sanitary napkin 100. The sanitary napkin 100 has the same planar shape as the sanitary napkin 10 'illustrated in Figure 2, but it has the following differences. The sanitary napkin has a rear portion 38 and a front portion 40. The rear portion 38 has an elevation 42. The elevation 42 forms a progressive elevation from its start zone in the immediate vicinity of the opening 34 to the end 44 of the sanitary napkin 100. The elevation 42 helps the user to properly place the sanitary napkin 100 between her legs at the perineum and between her buttocks. The front portion 40 is

  generally flat as best seen in Figure 8.

  The elevation 42 can be formed completely before the distribution of the sanitary napkin to the consumers. Alternatively, the elevation 42 may be present in a precursor state which allows the user to form the elevation 42 to its correct shape by folding the sanitary napkin 100 into the preferential fold that the precursor allows. This helps the user to form the profile of the towel. Depending on the nature and composition of the absorbent and the support material, the raised surface 42 can be formed in many ways, including by thermosetting, by using absorbents containing thermoplastic materials, by inclusion of support elements. thermoplastic and by choosing the components constituting the sanitary napkin 100 so that the elevation 42 is formed extemporaneously. Other approaches will be apparent to those skilled in the art for this.

  which is to create the fold line of the raised 42.

  The length and height of the ridge or elevation 42 in the rear portion 38 of the sanitary napkin 100 is determined by the sharpness of the fold and the arrangement of the absorbent 12. The pleat is useful for aligning the sanitary napkin 100 of such that the opening 34 is correctly aligned under the vestibule, and preferably under the vaginal opening, since the sanitary napkin 100 must be positioned on the body of the user. In use, the flattened portion 40 would be concave and generally extend over the pubic area of the user and over the front part of the lips. The elevation 42 would generally start in the rear part of the cleft of the lips, in the vicinity of the vestibule and would extend in

  direction of the perineum and buttocks.

  The use of sanitary napkins 10, 10 ', 10 "and 100 is similar. The separable member 20 is first removed to expose the body adhesive 14 upward and toward the wearer. 34 can be used to assist the user in positioning the sanitary napkin 10 'such that the opening 34 is located under the vaginal opening, the sanitary napkin 10' is then placed adjacent to the user by applying a sufficient pressure on the support sheet 18 of the sanitary napkin 10 'towards the body of the user to fix the napkin 10' on the user. The sanitary napkins 10, 10 ', 10 "and 100 can be formed in any size suitable for absorbing body exudates and they can have a total weight of between about 5 g and 12 g. In general, the sanitary napkin 10 'has a length of between about 17.78 cm and about 25.4 cm (7 inches to about 10 inches). The preferred length is generally between about 12.7 cm and 20.32 cm (5 inches to about 8 inches) since this length is discreet, efficient and easily placed in the correct position. The width is generally between about 5.08 cm and about 10.16 cm (2 inches to about 4 inches). The preferred width is approximately 6.35 cm (2.5 inches) for optimal comfort and efficiency in

  absorption of menstrual fluids.

  The production of sanitary napkins 10, 10 ', 10 "and 100 is done according to methods known in the art of manufacturing such laminate structures. To join the adhesive 14 to the surface on the body side 15, an intermediate adhesive is preferably used. to increase the bond of the adhesive 14 to the surface on the body side 15. Such adhesives include fusible construction adhesives, cohesive adhesives, and what is particularly preferred is a double-sided tape identified under the name tape double sided transfer 465 available

from 3M Corporation.

  Although the invention has been described with reference to catamenial pads, it is also useful for other absorbent articles such as protections against incontinence. In addition, the absorbent article can be given various shapes and sizes to better conform to the body of the users. These and other variants of the invention are included within the scope of

appended claims.

Claims (17)

  1 - absorbent article suitable for being fixed on the trunk of a carrier, said article comprising an absorbent (12) and an adhesive (14) located in the vicinity of said absorbent, which adhesive (14) fixes said absorbent on the trunk of the carrier, said article having a total weight greater than about grams. 2 - absorbent article according to claim 1, characterized in that it further comprises a barrier   impermeable to liquids (18) fixed to said absorbent (12).   3 - absorbent article according to claim 1,   characterized in that said adhesive (14) is a hydrogel.   4 - absorbent article according to claim 1, characterized in that said adhesive has a loss modulus between about 0.5 (104) dynes / cm2 and about 20 (104) dynes / cm2. - Absorbent article according to claim 1, characterized in that said adhesive (14) has a storage module of between approximately 0.2 (104) dynes / cm2 and approximately 45 (104) dynes / cm2.   6 - absorbent article according to claim 1, characterized in that said adhesive (14) has a loss module of between approximately 0.5 (104) dynes / cm2 and approximately (104) dynes / cm2 and a storage module of between   about 0.2 (104) dynes / cm2 and about 45 (104) dynes / cm2.   7 - Self-supporting absorbent article having an outer periphery (24) and which is adapted to be fixed on the trunk of a carrier, comprising: a. a liquid permeable top sheet (16);   b. a liquid impermeable backing sheet (18); vs. an absorbent (12) disposed between said top sheet (16) and said support sheet (18), said absorbent having a first surface (28) disposed toward said top sheet (16) and a second surface (30) disposed toward said support sheet (18), said absorbent (12) having a perimeter (22) located inside with respect to said outer periphery (24) of said article; and D. an adhesive (14) joined to said top sheet (16) to secure said absorbent to the trunk of the wearer. 8 - absorbent article according to claim 7, characterized in that it has total weight greater than about grams. 9 - absorbent article according to claim 7, characterized in that it comprises a separable element (20)   removably attached to said adhesive.   - Absorbent article according to claim 7, characterized in that said adhesive has a loss modulus of between approximately 0.5 (104) dynes / cm2 and approximately 20 (104) dynes / cm2.   11 - absorbent article according to claim 7, characterized in that said adhesive has a storage module of between approximately 0.2 (104) dynes / cm2 and approximately 45 (104) dynes / cm2. 12 - absorbent article according to claim 7, characterized in that said adhesive has a loss module of between approximately 0.5 (104) dynes / cm2 and approximately 20 (104) dynes / cm2 and a storage module of between approximately 0 , 2   (104) dynes / cm2 and about 45 (104) dynes / cm2.   13 - absorbent article according to claim 7, characterized in that said joining of the adhesive (14) to the absorbent (12) takes place approximately within 3 centimeters from said perimeter (22) of said absorbent (12). 14 - absorbent article according to claim 7, characterized in that it further comprises a drainage layer (32) disposed between said upper sheet (16) and said support sheet (18) for directing the fluid from   the body of a user towards said absorbent.   15 - absorbent article according to claim 14, characterized in that said drainage layer (32) is disposed in the vicinity of said second surface (30) of said absorbent (12), said drainage layer (32) having a higher drainage speed to that of said second surface (30).   16 - absorbent article according to claim 7, characterized in that said adhesive is a superimposed hydrogel   on less than 85% of said upper sheet (16).   17 - Self-supporting absorbent article comprising: a. a body side surface (15); b. a liquid impermeable backing sheet (18); vs. an absorbent (12) disposed between said body side surface (15) and said support sheet (18), said absorbent (12) having a first surface (28) disposed towards said body side surface (15) and a second surface ( 30) disposed in the direction of said support sheet (18), said first and second surfaces each having a through opening (34); and D. an adhesive (14) attached to said body side surface to secure said absorbent article (12) to the trunk of a being human.   18 - absorbent article according to claim 17, characterized in that said absorbent article has a longitudinal axis (X-X), said openings (34) in said first and second surfaces (28,30) being aligned coaxially and centered along said longitudinal axis (X-X).   19 - absorbent article according to claim 17, characterized in that it further comprises a drainage layer (32) disposed between said surface on the body side   (15) and said support sheet (18).   - Absorbent article according to claim 17, characterized in that between approximately 5% and approximately 95% of   said support sheet (18) are fixed to a neighboring layer.   21 - Self-supporting absorbent article having an outer perimeter (22) comprising: a. a body side surface (15) in which a portion of said surface comprises a liquid permeable top sheet (16); b. a liquid impermeable backing sheet (18) which partially covers and is attached to said top sheet (16); vs. an absorbent (12) disposed between said top sheet (16) and said support sheet (18), said absorbent (12) having a first surface (28) disposed toward said top sheet (16) and a second surface (30) arranged in the direction of said support sheet (18); and D. an adhesive (14) joined to a portion of said backing sheet (18) which wraps said body side face (15) to secure said absorbent article to the trunk of a human. 22 - absorbent article according to claim 21, characterized in that said support sheet (18) envelops said upper sheet (16) over a distance of between approximately 0.1 millimeter and approximately 30 millimeters at   from said outer perimeter (22).   23 - absorbent article according to claim 21, characterized in that it further comprises a drainage layer (32) disposed between said upper sheet (16) and said support sheet (18).   24 - Self-supporting sanitary napkin capable of absorbing bodily fluid from a woman's vagina, comprising: a. a liquid permeable top sheet (16) having a body side surface (15); b. a liquid impermeable backing sheet (18); vs. an absorbent (12) disposed between said top sheet (16) and said support sheet (18), said absorbent (12) having a first surface (28) disposed toward said top sheet (16) and a second surface disposed toward of said backing sheet (18), said first and second surfaces having through openings (34) coaxially aligned to direct said body fluid from said vagina to said second surface, said sanitary napkin having a flattened front portion adapted to be positioned approximately in front of said vagina and a rear portion having a raised area (42) adapted to be positioned approximately behind said vagina; and D. an adhesive (14) joined to said body side surface (15) to secure said sanitary napkin to the trunk of a human being.   - Sanitary napkin according to claim 24, characterized in that it comprises a longitudinal axis (X-X) and in that the openings (34) are centered along said longitudinal axis (X-X).   26 - Sanitary napkin according to claim 24, characterized in that said adhesive has a loss module of between approximately 0.5 (104) dynes / cm2 and approximately 20 (104) dynes / cm2 and a storage module of between approximately 0 , 2   (104) dynes / cm2 and about 45 (104) dynes / cm2.   27 - Sanitary napkin according to claim 24,   characterized in that said adhesive (24) is a hydrogel.