Stretch laminate, method of making, and absorbent article

ES 2 453 045 T3

DESCRIPTION

Tensioned laminate, manufacturing method and absorbent article

Field of the invention

The present description relates generally to a tensioned laminate and to a method of making the same, and to an absorbent article, such as a diaper, brief, or the like, manufactured using the tensioned laminate.

Background of the invention

Disposable absorbent items, such as diapers, are designed to contain body exudates, such as urine, to prevent staining of the wearer's clothing and / or other items (for example, a bed, chair, sheet , etc.). The fit of the article to the wearer's body is important to ensure that this debris is contained rather than leaking. The fit of the article to the wearer's body can be affected by the size of the opening in the waistband of the diaper, the size of the openings around the thighs, and the length or "thread pitch" of the diaper.

Disposable absorbent items are also designed to be inexpensive. That is, the average consumer may have another idea about the use of a product that he considers himself disposable if the cost of the article is too high. Thus, manufacturers generally manufacture such articles for use by individuals with a wide range of body types that can be classified according to broad criteria, such as weight.

It will be recognized that the need to manufacture products to fit a wide range of body types competes with the desire for the article to fit closely to the wearer to contain waste and limit leakage.

One way that manufacturers try to balance conflicting interests between a correct fit and a variation in body type is by using materials that can be expanded. One of this group of materials is known as stressed laminates. As the name suggests, these materials are really individual component composites that are laminated together, through the use of an adhesive, for example. A typical tensioned laminate will attempt to combine an inner layer defined by a material of good elastomeric properties, to accommodate varying body types, with an outer layer or layers defined by a woven-type material, to accommodate the user's expectations of look and feel. WO2005 / 065932 A1 describes a bonded tensioned laminate which can be rolled up without problems due to roll blocking. The laminate comprises an elastic layer which can be a film and an opposite layer attached to only one side of the elastic layer.

A complication arises because the outer layer or layers of these stressed laminates can inhibit the functioning of the inner layer having good elasticity. Consequently, stressed laminates often undergo a processing step, known as activation, prior to use in the manufacture of an absorbent article, such as a diaper or brief, for example. During activation, mechanical deformation is imposed on the laminate so that the composite material exhibits better elasticity, while providing the desired look and feel.

Unfortunately, the activation process can have unintended consequences for the materials that comprise the laminate. For example, mechanical damage to the inner elastomer layer can occur, as manifested by cracks or holes in the elastomer, which can occur during the activation process. These holes can be macroscopic, and can be several millimeters in diameter. If an excessive number of holes appear, the user may perceive that the laminated material is defective, or that it may not provide the desired fit or performance properties.

One solution has been to use larger thicknesses, or gauges, in the inner layer material. Another alternative has been the use of non-woven products specially designed and manufactured to be compatible with the activation process (ring lamination) of the outer layers. Both solutions increase the cost of the resulting laminate.

Thus, it would be desirable to provide new stressed laminates and methods for making the stressed laminates. In particular, it would be desirable to provide less expensive laminates produced using less expensive materials.

Summary of the invention

In one aspect, a tensioned laminate is provided comprising that set forth in claim 1.

In another aspect, there is provided a method of manufacturing a stressed laminate as set forth in claim 6.

ES 2 453 045 T3

Additional aspects of the description have been defined by the claims of this patent.

Brief description of the drawings

Although the specification concludes with claims that specifically state and specifically claim the object under consideration to be the present invention, it is believed that the invention will become more fully understood from the following description, in combination with the drawings that follow. accompany. Some of the figures may have been simplified by omitting selected elements in order to show other elements more clearly. Such omissions of elements in some figures are not necessarily indicative of the presence or absence of specific elements in any of the illustrative embodiments, unless otherwise indicated in the corresponding written description. None of the drawings are necessarily to scale.

Fig. 1A is a side view of a first embodiment of a tensioned first laminate according to the present disclosure;

Fig. 2 is a schematic of a clamp that can be used in a test performed on specimens of an elastomer to determine whether the elastomer meets a strength criterion;

Fig. 3 is a graph illustrating a strain rate that can be used in a test performed on specimens of an elastomer to determine whether the elastomer meets a strength criterion;

Fig. 4 is a graph illustrating the results of testing performed on specimens of various elastomers to determine whether said elastomers meet a strength criterion;

Fig. 5 is a schematic of an adhesive design used to bond the elastomer and nonwoven layers of the tensioned laminates used in the comparative tests.

Fig. 6 is a graph illustrating the results of comparative tests performed on specimens of stressed laminates made with and without an elastomer that meet the strength criteria defined herein;

Fig. 7 is a plan view of an illustrative absorbent article including sections made with the tensioned laminate of Fig. 1A with a topsheet section removed to expose an underlying absorbent core; Y

Fig. 8 is a perspective view of the absorbent article of Fig. 7 shown in its relaxed and contracted state, that is, with elastic element-induced contraction.

Detailed description of the invention

Definitions

As used herein, the following terms have the following meanings:

The term "absorbent article" refers to a device that absorbs and contains liquids, and more specifically, refers to a device that is positioned close to the wearer's body to absorb and contain the various exudates discharged by the body.

The terms "adhesively bonded" or "adhesively laminated" refer to a laminate in which an adhesive has been used to bond the elastomeric element to woven or non-woven materials.

The term "bonded" refers to elements that are connected or joined by fastening, adhering, bonding, etc., by any method suitable for the elements that are connected to each other and their constituent materials. Many suitable methods for joining elements together are well known, including adhesive bonding, pressure bonding, thermal bonding, mechanical clamping, etc. Such joining methods can be used to join elements together in a particular area both continuously and intermittently.

The term "diaper" refers to an absorbent article generally worn by children and incontinence sufferers around the lower part of the torso and having the general shape of a sheet, the different parts of which are fastened together to encircle the waist and the wearer's legs.

The term "disposable" refers to absorbent articles that are generally not intended to be washed or recovered or otherwise reused as an absorbent article, that is, they are intended to be disposed of after a single use and, preferably, to be recycled, Composted or otherwise disposed of in an environmentally friendly way.

The term "arranged" is used to indicate that one or more elements are formed (joined and placed) in a particular place or position as a unitary structure with other elements or as a separate element joined to another element.

ES 2 453 045 T3

The terms "interior" and "exterior" may refer respectively to the location of an item that is intended to be placed against or toward the body of a wearer when the absorbent article is worn and the location of an item that is intended to be worn. against or towards any garment worn over the absorbent article. "Interior" and "exterior" can also refer to a particular orientation of elements related to each other, without special reference to the wearer. The synonyms "interior" and "exterior" include, respectively, "internal" and "external," as well as "inside" and "outside." Also, when an absorbent article is oriented so that its inner faces are oriented upward, for example when it is laid down in preparation to fit over the wearer, synonyms include "top" and "bottom" and "top" and "bottom." , respectively.

The term "bonded" refers to configurations where an element is attached directly to another element by fixing the element directly to the other element, and configurations where an element is indirectly fastened to another element by joining the element to one or more intermediate element (s) ( s) which, in turn, are attached to the other element.

The term "lateral" or "transverse" refers to a direction located at an angle of 90 degrees to the longitudinal direction and includes directions at ± 45 degrees from the lateral direction.

The term "longitudinal" refers to a direction that runs parallel to the maximum linear dimension of the article and includes directions within ± 45 ° of the longitudinal direction.

The term "macroporous" refers to materials that have pores that are too large to effect capillary fluid transport, generally have pores greater than about 0.5 mm in diameter, and more specifically, have pores greater than about 1.0 mm in diameter. diameter. The term "microporous" refers to materials that are capable of LaPlace pressures greater in magnitude than about 10 kPa.

The term "brief" or "briefs" refers to an absorbent article generally worn by children and incontinence sufferers around the lower torso and has the general shape of short briefs that can be applied to and removed from the wearer without unbuttoning. . A panty can be donned by inserting the wearer's legs into the leg openings and lifting the diaper panty to approximately the wearer's lower torso. Although the term "brief" is used herein, briefs are also commonly referred to as "closed diapers," "pre-attached diapers," "adjustable diapers," "diaper briefs" and "brief-diapers.

The term "reseachable" refers to the property of two elements that can release the joint, separate, and subsequently rejoin in a resealable manner without substantial permanent deformation or breakage.

The terms "releasably attached", "releasably attached" and variations thereof refer to two elements that are connected or that can be connected such that the elements tend to remain connected in the absence of an applied separation force. to one or both of the elements, and the elements are capable of being separated without substantial permanent deformation or breakage. The separation force required is typically greater than that which appears while wearing the absorbent garment.

Laminate laminate and manufacturing method

FIG. 1A illustrates one embodiment of a tensioned laminate 20 in accordance with the present disclosure. According to this embodiment, the laminate 20 can include three layers: a first layer 22, or internal, and a second and third layers 24, 26 or external.

The first, second and third layers 22, 24, 26 are bonded to each other. For example an adhesive may be disposed between layers 22, 24, 26, as shown at 30, 32. As will be recognized, adhesive 30 may be initially positioned on either a surface 40 of layer 22 or a surface 42 of the layer 24, and adhesive 32 may likewise be initially disposed on either an opposite surface 44 of layer 22 or a surface 46 of layer 26. Assembled, adhesive 30 bonds surface 40 (and therefore layer 22) to surface 42 (and therefore layer 24), and adhesive 32 bonds surface 44 (and therefore layer 22) to surface 46 (and therefore layer 26).

Although it appears that the layers 22, 24, 26 appear to cover each other completely, this need not be the case in all embodiments. For example, layers 24, 26 can extend beyond layer 22, and can be bonded together while layers 24, 26 extend beyond layer 22; alternatively, layers 24, 26 may not extend to the limits of layer 22. Also, although the adhesive 30, 32 appears to be a continuous layer in the Figure, the adhesive 30, 32 can be applied as a continuous layer or in a discontinuous pattern (such as a pattern of lines, spirals, or dots). In addition, alternative attachment mechanisms may include thermal bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other suitable bonding mechanism or combinations of these bonding mechanisms.

According to the present disclosure, the inner layer 22, or core, may include a woven elastomer. Illustrative elastomer films may include those elastomer films having a design tensile strength greater than 14 MPa, when measured at a design strain rate of about 600 / s. On

In certain embodiments, the design tensile strength may be greater than about 20 MPa, when measured at a design strain rate of about 600 / s. These illustrative elastomer films may also have a design tensile strength greater than about 7 MPa, measured at a strain rate of about 600 / s, in a high-speed scoring test, as described in more detail below. . In certain embodiments, the design tensile strength can be greater than about 15 MPa, when measured at a design strain rate of about 600 / s in a high speed test with grooving. At this time, it is believed that high speed resistance, where resistance is measured by notching the specimen, can be significant in selecting suitable elastomer films. However, it may be that such elastomeric films showing high strength at high speeds in notched or unnotched tests may have even greater suitability for use in stressed laminates than elastomers showing high tensile strength in testing. both notched and not notched. It may also be the case that the tensile strength in the notched test is more significant in selecting a suitable material than the test with the original unnotched material.

Illustrative elastomer films can include those with skins and those without skin. However, while skins may be useful in preventing blockage, it is believed that they do not contribute substantially to the ability of the film to prevent damage during activation at the relevant layer ratios to achieve good elastometric properties. Instead, as explained in more detail below, the mechanical properties of the elastomer (eg, design strength) are believed to be the primary concern for high speed mechanical integrity in the context of activation.

An illustrative elastomeric film that meets the tensile strength requirements provided above can be manufactured according to the following illustrative method. An UltraGlide twin screw extruder, available from Berstorff GmbH of Hannover, Germany (25.4mm diameter and L: D = 32) was used with 253-128 resin available from GLS Composites Distribution Group of McHenry, Illinois. USA The extruder was equipped with a vibrating feeder to supply the resin granules to the feed mouth of the extruder at a constant speed. Extrusion temperatures were set at approximately 149 ° C (300 degrees F) for the first extrusion zone and approximately 221 ° C (430 degrees F) for the last extrusion zone and the die and selected for the intermediate zones to achieve a suitable upward ramping temperature profile. Screw speed was approximately 100 rpm. The extruder was equipped with a 15.2 cm (6 inch) wide film die, and the film was cast directly onto the adhesive backing paper in a suitable film pick-up apparatus.

The outer layers 24, 26 can be a nonwoven material, such as SM (melt blown spunbonded), SMS (melt blown spunbonded), and SMMS (melt blown spunbonded). spunbonded). To this end, the spunbonded materials can also be specially designed and / or manufactured to be compatible with the activation process. However, it is believed that by using the elastomer layer in accordance with the present disclosure, greater design options can be achieved. For example, spunbonded materials can be selected for applications where only carded nonwovens have been used in the past. The skilled technician will recognize other improvements in design flexibility.

The grammage of the non-woven material can be less than about 25 g / m2². In fact, according to some embodiments, the grammage may be less than about 22 g / m2.². In other embodiments, the grammage may be less than about 20 g / m2.². In still other embodiments, the nonwoven may have a grammage of less than about 18 g / m2.².

The adhesive 30, 32 may be selected from those adhesives known to provide a suitable bond between the fabric 22 and the layers 24, 26 of non-woven material. According to one embodiment, the adhesive may be commercial adhesive H2031, an adhesive sold by Bostik Inc. of Middleton, Massachusetts, USA. A characteristic of this adhesive is that, at 23 ° C, this adhesive has a significant pressure sensitive character useful for making laminates by hand. However, this adhesive is also suitable for use in making laminates from films and the nonwovens listed above using conventional laminate manufacturing equipment, such as equipment that is well known in the art.

An illustrative method of making a laminate using the aforementioned films, nonwovens and adhesives is as follows. The adhesive 30 is originally disposed on a sheet of adhesive backing paper. The adhesive 30 can be transferred to one side 42 of the nonwoven 24 by placing the sheet of the nonwoven 24 over the adhesive 30, and then applying sufficient pressure to the nonwoven 24, with a hand roller, for example. The adhesive 30 and the nonwoven material 24 are gradually peeled off the backing paper of the adhesive, and applied to the surface 40 of the film 22. This procedure can be repeated to bond the other nonwoven 26 to the adhesive 32, and then the nonwoven 26 and adhesive 32 to surface 44 of film 22. Once layers 22, 24, 26 have been assembled, a hand roller can be used, for example, to apply moderate pressure to laminate 20 to provide laminate 20 with adequate peel strength (approximately 1-2 N / cm) . It will be recognized that these steps can be carried out on conventional manufacturing equipment, to the best of knowledge of those skilled in the art.

ES 2 453 045 T3

The laminate can then be subjected to a process sometimes referred to as "ring lamination". During the ring rolling process, intermeshing corrugated rollers are used to permanently elongate the substrate to reduce its tensile strength. The resulting laminate has a higher degree of stretch in the parts that have been subjected to the ring lamination process. Thus, this secondary operation provides additional flexibility to achieve stretching properties in localized parts of the stressed composite. Methods for imparting stretchability to a stretchable or substantially inelastic material through the use of intermeshing corrugated rollers that produce increasing stretch in the machine or cross-machine direction and permanently deform the material have been described in US -4,116,892; US 4,834,741; US 5,143,679; US 5,156,793; US-5,167,897; US-5,422,172; and US5,518,801. In some embodiments, the intermediate structure can be fed to the intermeshing corrugated rollers at an angle to the machine direction of this secondary operation. Alternatively, the secondary operation may employ a pair of intermeshing grooved plates applied to the intermediate structure under pressure to achieve increasing tensioning of the intermediate structure in localized parts.

It is believed that an elastomer of the present disclosure, exhibiting high tensile strength at high speeds (which can be expressed in the form of high rates of strain), can improve the performance characteristics of the stressed laminate 20 manufactured using the elastomer. , leading to potential reductions in the cost of the stressed laminate. For example, it is theorized that the formation of mechanical injuries (eg, breaks and holes) during activation can be inhibited or limited by an elastomer exhibiting high tensile strength at high speeds relative to the relevant stress range. In this regard, it will be readily recognized that a high strength material that breaks at less deformation than that experienced by laminate during ring rolling processes, for example, will not be acceptable. As long as the design strain of the material at break is large enough to accommodate the ring rolling process, it is believed that the tensile strength of the elastomer may be the primary criterion for preventing film damage (e.g. example, breaks or holes). The reduction in the cost of a laminate using such a high-strength elastomer can come from different aspects. For example, if the laminate (in particular, the elastomer) is more resistant to pinhole formation, it may be possible to use a smaller gauge of elastomeric film for a particular laminate, resulting in a reduction in the costs of material. Similarly, the use of the elastomer in accordance with the present disclosure may limit the need to use a larger gauge elastomer film that might otherwise be necessary in a particular application. As another alternative, non-carded nonwovens, such as spunbonded materials that can be less expensive than carded nonwovens, can be used in particular applications where the use of such nonwovens was not typical. if an elastomeric film was used according to the present description.

Tensile test methods and results

Illustrative methods of testing an elastomer to determine if it meets the strength criteria are listed below. In particular, elastomers were tested for their tensile strength, which can be expressed as the maximum design stress experienced by a specimen prior to failure.

Illustrative strength testing methods were performed with an 810 Material Testing System, marketed by MTS Systems Corporation of Eden Prairie, Minnesota, USA In particular, the system used was provided with a servo hydraulic actuator suitable for speeds exceeding 5 m / s after 28 mm of travel, and approaching 6 m / s after 40 mm of travel. The system was also fitted with a 50 lb (23 kg) Kistler force transducer with signal conditioning via a Kistler 5010 dual-mode amplifier.

The normal and scored specimens were prepared for analysis. In this regard, it was observed that holes formed in the elastomer layer of a stressed laminate can be considered as a material defect. Accordingly, it is believed that a notch in the specimen provides an adequate simulation of hole formation in the specimen, and that the tensile strength of the grooved specimen may provide useful information for setting criteria to limit hole formation in the specimen. elastomer layer.

For both normal and scored specimens, the film was initially placed between two sheets of paper. A sharp blade, such as a XACTO knife sold by the Hunt Corporation of Philadelphia, Pennsylvania, eE. USA, and a straight edge of metal were then used to trim a specimen that was 19mm wide by approximately 16.5mm long from the film. The machine direction of the film and the cross direction (also known as the cross direction) match the dimensions of 19mm and 16.5mm, respectively, so that the specimen will be deformed along its transverse direction during test. The 16.5 mm dimension of the specimen was measured with a 0.2 mm precision ruler and weighed on a 4-digit laboratory balance.

With respect to the grooved specimens, a 1 mm notch was cut on the edge of the specimen perpendicular to the edge of the specimen. The notch was trimmed with a XACTO knife and milled steel plate

ES 2 453 045 T3 with a suitable guide formed in the previous one. Each notch was measured with a magnifying glass (7x) and a suitable graticule, and only specimens with notches in the range of 1 mm ± 0.1 mm were used in the test.

According to illustrative test methods, the system was provided with a series of custom-made flanges 80, as illustrated in Fig. 2, for mounting the specimens thus prepared. The flange 80 has a stationary element 82 and a movable element 84. The stationary element 82 has a cavity 86 formed in the former to house a bolt that can be attached to the torque pick-up (not shown) of the system. The stationary element 82 also has a surface 88 to which a mounting plate 90 has been attached, the mounting plate 90 being formed of urethane rubber, for example. Movable member 84 has a surface 92 facing surface 88. A tip 96 is dependent on surface 92, said tip 96 may have a radius of approximately 1mm. Each movable member 84 has a passage 100 through which a bolt 102 is disposed. The passage 98 defined in the stationary element 82 may be threaded such that the threads of the bolt 102 engage the threads of the passage 98 to hold the movable element 84 in a relatively fixed relationship with respect to the stationary element 82 with an edge of the specimen. disposed between tip 96 and mounting plate 90 to provide a line of contact with the specimen.

The specimens were mounted on the custom made flanges as follows. The flanges were first moved to a flange gap (ie the distance between the contact lines between the specimen and the flange surface of 10 millimeters. The specimen was then mounted on the flanges. Optionally a powder can be used , such as cornstarch, and a thin piece of tape during the assembly process. Dust can be used to limit specimen adhesion, while tape can be used to help hold the specimen straight and flat during mounting to flanges. If tape is used, it is recommended that the tape remain behind the clamp lines so that the tape does not interfere with the specimen gauge during testing. The flanges were then moved closer together to introduce considerable sag into the specimen, but not so close that the flanges interfere with each other.

The specimen, thus assembled, can be tested as follows, although other methods can be used. The movement of the actuator was initiated according to the deformation pattern shown in Figure 3 at room temperature (23 ° C) and a dynamometric sensor selected according to the operator's experience was used. The reference length (the distance between the flange contact lines when the undeformed specimen was mounted on the flanges) was 10 mm for all specimens tested. The data record of the actuator force and displacement during the test was captured with a Nicolet Integra oscilloscope. The typical data acquisition frequency under the experimental conditions described above can be 40 kHz.

Results

The test results have been summarized herein, and in the graph of Fig. 4. The results are expressed in terms of design stress, design strain, and design strain rate. In this regard, the following relationships are indicated.

The sigma of the design stress (expressed in MPa) can be calculated using the equation:

0- = 10 ⁶ *

A where F is force (expressed in Newton) and A is the cross-sectional area of ​​the specimen (expressed in m²). For this calculation, the specimen's own cross-sectional area was calculated according to the following equation:

, m

A = - Z * p where m is mass (expressed in kg), l is the dimension along the deformation direction (expressed in m), and ρ is density (in kg / m³). Measurements of mass and length of the individual specimen were taken as described above. The density was taken as 950 kg / m³ or 920 kg / m³ for elastomers comprised predominantly of non-hydrogenated and hydrogenated SBC, respectively, according to historical standards for similar elastomers and determined by methods known to those skilled in the art (such as density gradient columns, or application of Archimedes' principle). Density values ​​are believed to be accurate to about 5% for the specimens described herein.

The design deformation ε (dimensionless) is defined as

L- L_ñz ε = --- = -

ExA) where L0 is the reference length - the distance between the contact lines of the flange when the specimen was mounted without deformation on the flanges (expressed in m), L is the position of the flange - the distance between the lines of

ES 2 453 045 T3 contact of the flange during the tensile test (expressed in m) and z is the displacement - defined as z = LLo (expressed in m).

The design strain rate (expressed in s^-1) is the first time derivative of the design deformation. Therefore, the rate of deformation can be calculated according to:

ds _ v dt Lo where ν is the speed at which one flange moves with respect to the other (expressed in m / s), and L0 is the reference length (expressed in m).

Six different elastomer films (identified as AF films herein) were tested for their tensile strength. The films had weights between approximately 80 g / m2² and about 100 g / m². Films were prepared according to two different methods.

Five of the films (AE) were prepared according to the following method: An UltraGlide twin screw extruder, marketed by Berstorff GmbH of Hannover, Germany (25.4mm diameter and L: D = 32) was used. The extruder was equipped with a vibrating feeder to supply the resin granules to the feed mouth of the extruder at a constant speed. Extrusion temperatures were set at approximately 148 ° C (300 ° F) for the first extrusion zone and approximately 221 ° C (430 ° F) for the last extrusion zone and the die and selected for the intermediate zones to achieve a suitable upward ramp temperature profile. Screw speed was approximately 100 rpm. The extruder was equipped with a 15.2 cm (6 inch) wide film die, and the film was cast directly onto the adhesive backing paper in a suitable film pick-up apparatus.

The sixth film (F) was prepared according to the following method: A small amount of resin was compression molded to a thickness of 150-200 microns using conventional equipment. The resin was placed between layers of polytetrafluoroethylene (PTFE) film. The unit thus formed was then arranged between plates held at approximately 232 ° C (450 ° F) for a residence time of approximately 30 seconds.

Film A was formed with a 253-128 resin available from GLS Composites Distribution Group of McHenry, Illinois, USA Film B was formed using approximately 83% by weight of a Vector 4211 resin available from Dexco Polymers LP of Plaquemine, Louisiana, USA, and about 17% by weight of a PS3190 resin available from Nova Chemicals Corp. of Calgary, Canada. Film C was formed using only Vector 4211 resin. Film D was formed using approximately 83% by weight of a D1164 resin available from Kraton Polymers LLC of Houston, Texas, USA, and approximately 17% by weight of PS3190 resin. Film A was formed with a 148-089 resin available from GLS Composites Distribution Group. Film F was formed with a PG-C-016 resin available from Kuraray America Inc. of New York, New York, USA.

The results of the tests carried out on the six films are summarized in the following table, for both original (not notched) and scored specimens. Additionally, the test results for both the original and scored specimens of the AC films are also shown in Fig. 4.

<td colspan="3">Tensile strength results</td>

<td>Film identifier</td><td>Original specimen Tensile strength (in MPa)</td><td>Grooved specimen Tensile strength (in MPa)</td>

<td>TO</td><td> 20,0</td><td> 15,4</td>

<td>B</td><td> 19,6</td><td> 6,9</td>

<td>C</td><td> 10,6</td><td> 5,0</td>

<td>D</td><td> 19,3</td><td> 7,2</td>

<td>AND</td><td> 15,5</td><td> 4,6</td>

<td>F</td><td> 15,9</td><td> 14,0</td>

It is currently believed that the elastomeric film with the highest design tensile strength, in both notched and unnotched tests, will best show the desired improvements in design flexibility.

ES 2 453 045 T3 described above: ie elastomer film A. However, it is also believed that suitable improvements in design flexibility can be achieved with elastomer films B, D, and F, for example.

The AC films, previously tested for their tensile strength, were also used for comparative tests involving the activation of laminates formed using the elastomer films. Illustrative test methods are listed below.

Three-layer laminates were prepared using the film of interest (film A, B, or C) prepared with a grammage between about 48 and about 52 g / m2.², a non-woven material H0101711 having a grammage of approximately 17 g / m2² and sold by Fibertex A / S of Aalborg, Denmark, and an H2031 adhesive sold by Bostik Inc. of Middleton, Massachusetts, USA, with a grammage selected to provide a bond strength to the laminate of approximately 1-2 N / cm. The adhesive was applied to a protective paper sheet of the silicone adhesive with a spiral design with the desired grammage, which was between approximately 4.7 g / m² and about 9.3 g / m². In particular, ITW D70 nozzles were used, with a selected flow rate, nozzle height, air and temperature settings to provide suitable adhesive spirals. The adhesive backing was mounted on an XY table programmed to track and index so that the spirals of adhesive have a suitable spatial relationship to each other, eg slight overlap (see Fig. 5). The adhesive was transferred from the adhesive backing paper to a first layer of the nonwoven by laying the nonwoven layer over the adhesive. A hand roller was used to apply the necessary pressure to the adhesive and the nonwoven material to be able to peel them both from the adhesive backing. Next, the film was laid on the adhesive, and the roller was applied. This procedure was repeated to apply a second layer of nonwoven material to the other surface of the film. Once both layers of nonwoven material were applied to the film, the hand roller was used to apply more pressure in several repetitions, until the bond strength of the laminate was "saturated," that is, did not increase significantly with lamination or additional pressure.

Sheets of the laminate with dimensions of approximately 150 mm in length by approximately 80 mm in width (in the machine and transverse directions, respectively), were subjected to activation processing. Specifically, the sheets were mounted in a press such as that described in US-6843134 and US-6915700 and publication US-2004/0177709. The blades were oriented so that the transverse direction of the blade coincided with the direction of the press teeth. The following parameters were used:

Roller diameter: 152.4 mm

Belt speed: 2.75 m / s

Tooth tip radius: 0.102mm

Tooth thread pitch: 3.81mm

Tooth Height: 25.3mm

Tooth: 23

Bonding degree: 4mm to 11mm

The activated region of each specimen was approximately 100 mm in length (determined by the number of teeth used) by approximately 80 mm in width (determined by the width of the blade). After activation, each specimen was examined for locations with breaks (ie, holes) in the film. The number of holes present was counted and summarized in the following table. Additionally, the test results for laminates made with AC Films are also shown in Fig. 6.

<td colspan="4">Hole count</td>

<td>Bonding degree (in mm)</td><td>Stratified with film A</td><td>Stratified with B film</td><td>Stratified with C-film</td>

<td> 4</td><td> 0</td><td></td><td> 2</td>

<td> 4,5</td><td> 0</td><td> 0</td><td> 1</td>

<td> 5</td><td> 0</td><td> 2</td><td> 4</td>

<td> 5,5</td><td> 0</td><td> 2</td><td> 13</td>

<td> 6</td><td> 0</td><td> 8</td><td> 16</td>

<td> 6,5</td><td> 0</td><td> 4</td><td></td>

ES 2 453 045 T3

<td colspan="4">Hole count</td>

<td>Bonding degree (in mm)</td><td>Stratified with film A</td><td>Stratified with B film</td><td>Stratified with C-film</td>

<td> 7</td><td> 0</td><td></td><td></td>

<td> 8</td><td> 0</td><td></td><td></td>

<td> 9</td><td> 5</td><td></td><td></td>

<td> 10</td><td> 11</td><td></td><td></td>

This test method is believed to provide a quantitative measure that can support the assessment made above: that Film A provides a stressed laminate with better performance than stressed laminates made from the rest of the films tested. It will be recognized that the tensioned laminate made using Film A elastomer has fewer holes for higher degrees of bonding than laminates made from Film B and C elastomers. It is believed that this may allow for a smaller gauge (thickness) of film A in a given application than for film B or C, or that a greater range of nonwoven options may be available for a laminate where it is used film A elastomer than is possible with film B and C elastomers. The test results are also believed to show the difference in performance between laminates using film B compared to laminates made with film C, for example.

Illustrative absorbent article

Having thus described the stressed laminate in accordance with the present disclosure and the methods for its manufacture and testing, the use of the stressed laminate in an absorbent article will now be described. Although the use of the tensioned laminate is suggested with respect to certain regions of the absorbent article, it will be recognized that the tensioned laminate can also be used in other regions as well.

FIG. 7 is a plan view of an illustrative disposable absorbent article 120 in its flat, uncontracted state, that is, without elastic-induced shrinkage. Portions of article 120 have been cut out to more clearly show the underlying structure of disposable absorbent article 120. As illustrated, the portion of the disposable absorbent article 20 that is in contact with the wearer is visible to the viewer (ie, showing the inside or inside face of the article). The disposable absorbent article 120 has a longitudinal axis 130 and a transverse axis 132.

A rear portion of the disposable absorbent article 120 is configured as a first waist region 140 of the disposable absorbent article 120. The opposite end portion is configured as a second waist region 142 of the disposable absorbent article 120. The waist regions 140 and 142 generally comprise those portions of the disposable absorbent article 120 which, when donned, surround the wearer's waist. Waist regions 140 and 142 may include elastic members that cinch around the wearer's waist to provide a better fit and confinement. An intermediate portion of the disposable absorbent article 120 is configured as a crotch region 144 extending longitudinally between the first region 140 and the second waist region 142. The crotch region 144 is that portion of the disposable absorbent article 120 which, when the disposable absorbent article 120 is used, is generally positioned between the wearer's legs.

The disposable absorbent article 120 has a laterally extending waist edge 150 in the first waist region 140, and a second laterally extending waist edge 152 in the second waist region 142. The disposable absorbent article 120 has a first side edge 154 and a second side edge 156 opposite the previous one, both side edges extending longitudinally between the first waist edge 150 and the second waist edge 152. The portion of the first side edge 154 of the first waist region 140 is designated 154a, the portion in the crotch region 144 is designated 154b, and the portion in the second waist region 142 is designated 154c. The corresponding portions of the second side edge 156 are designated 156a, 156b, and 156c, respectively.

The disposable absorbent article 120 preferably comprises a water-permeable topsheet 160, a water-impermeable backsheet 162, and an absorbent unit or core 164, which may be positioned between the topsheet 160 and the backsheet 162, with the topsheet 160 attached to backsheet 162. The topsheet 160 may be fully or partially elasticized or may be reduced. Illustrative structures including elasticized or reduced topsheets have been described in greater detail in US 4,892,536; US 4,990,147; US 5,037,416; and US-5,269,775, among others.

The disposable absorbent article 120 may include at least one characteristic elastic waist element 170 that helps provide better fit and containment. The characteristic elastic waist element 170 may be

ES 2 453 045 T3 designed to elastically expand and contract to dynamically fit the wearer's waist. The characteristic elastic waist element 170 may extend at least longitudinally outward from at least one waist edge (eg, edge 150) of absorbent article 150 and generally forms at least a portion of the waist region ( for example, region 140) of absorbent article 120. Often times, diapers are assembled to have two characteristic elastic waist elements 170, 172, one (170) positioned in the first waist region 140 and one (172) positioned in the second waist region 142. In addition, the elastic waist feature 170, 172 may be made of the tensioned laminate 20 attached to the backsheet 162. Alternatively, elastic waist feature 170, 172 may be mounted as an extension of other elements of the absorbent article such as topsheet 160, backsheet 162, or both topsheet 160 and backsheet 162 ( for example, topsheet 160 or backsheet 162 defines one of layers 24, 26 of laminate 20). Other constructions of the elastic waist feature have been described in US 4,515,595; US-4,710,189; US 5,151,092; and US-5,221,274.

The absorbent article 120 may include side panels 180, 182 attached to the backsheet 162. One or more of the side panels 180, 182 may be made of the tensioned laminate 20. This structure can provide a more snug and snug fit by initially snuggly fitting absorbent article 120 to the wearer and maintaining this fit throughout the time of wear and even later after absorbent article 120 has been loaded with exudate as the side panels Elastic 180, 182 allow the sides of absorbent article 120 to extend and contract. Side panels 180, 182 can also provide more efficient application of absorbent article 120 because, even if the diaper user pulls on one elastic side panel 180 more than the other during application, absorbent article 120 "self-adjusts". during use. Although absorbent article 120 preferably has side panels 180, 182 disposed in second waist region 142, absorbent article 120 may be provided with side panels disposed in first waist region 140, or both front and front waist region 140. in the second waist region 142.

Fig. 8 shows the article shown in Fig. 7 configured as if it were to be worn. The disposable absorbent article 120 may be side sealed so that it is configured as shown in Fig. 8. However, the article 120 may instead include resealable seams 170 that can be used to fasten the regions 140, 142 waist to each other. According to an illustrative embodiment, the waist regions 140, 142 can be buckled on the sides to apply the article with a diaper. According to an illustrative embodiment, shown in Fig. 8, the side seams 170 may include fasteners 172 that can be used to configure the article as a pair of training panties or disposable panties.

As illustrated, fasteners 172 may be disposed within the disposable absorbent article 120 at the second waist region 142 adjacent to portion 154c of the first side edge 154 and adjacent to portion 156c of the second side edge 156. The portion 154c of the side edge 154 is shown open, such as before closing and fastening or after being reopened. Portion 156c of opposite side edge 156 is shown buckled, that is, formed into the panty shape. In FIG. 8, the second waist region 142 overlaps the first waist region 140 when buckled together.

The fasteners 172 can be formed of any material and have any shape that allows them to releasably bond to the even surface in the opposite waist region when pressed again. For example, the primary component of the fastener may be a mechanical fastener that releasably engages the smooth surface, such as through a plurality of hooks that engage fiber-formed loops in a nonwoven sheet. Alternatively, the main component of the fixative may be an adhesive that releasably adheres to the smooth surface. In fact, fasteners may include taped tabs, hook and loop fasteners, interlocking fasteners such as tab and buckle grooves, buttons, snaps, and / or tongue and groove fastening components. Illustrative surface attachment systems have been described in US-3,848,594; US-4,662,875; US-4,846,815; US 4,894,060; US 4,946,527; US5,151,092; and US-5,221,274, while an interlocking fixation system has been described in US-6,432,098. The fixation system can also include primary and secondary fixation systems, as described in US-4,699,622. Illustrative additional fasteners and fastener arrangements, the fastener components that make up such fasteners, and materials that are suitable for forming fasteners have been described in published US applications US-2003/0060794, US-2005/0222546, and US- 6,428,526.

Other variations are still possible. For example, the fasteners 172 may be disposed within the article 120 in the first waist region 140 such that the first waist region 140 overlaps the second waist region 142 when both are fastened together. As another example, fasteners 170 may be disposed on the outside of article 20 rather than on the inside. As a further example, fasteners 170 can be used with a specifically matched fastening surface especially suitable to cooperate with fasteners 170 (for example, a loop layer that works with a hook fastener, or a layer specially treated to provide a surface suitable for a specific adhesive).

Additional variations of the absorbent article

As an alternative to the absorbent article 120 described above, various units of topsheet 160, backsheet 162, and absorbent core 164 can be used.

In structures, the topsheet, for example, can be varied through the use of coatings, lotions, and the like. Furthermore, in addition to the features described above, the disposable absorbent article 120 may include a variety of other features, such as slit openings, hollow spaces, leg pads, and the like, to provide the desired fit, confinement, and aesthetic properties. In addition, a transfer layer, which may also be referred to as a pick-up or distribution layer, or a sublayer, can be placed between the topsheet 160 and the core 164.

Thus, the topsheet, the backsheet, and the absorbent core can alternatively be assembled in any of the well-known configurations described in the following patent documents: US-3,860,003; US 5,151,092; US 5,221,274; US-5,554,145; US-5,569,234; US-5,580,411; and US 6,004,306 (diapers) and US 5,246,433; US-5,569,234; US 6,120,487; US 6,120,489; US 4,940,464; US 5,092,861; US-5,897,545; and US5,957,908 (panties).

The topsheet can be manufactured from a wide range of materials, such as porous foams, cross-linked foams, apertured plastic films, or continuous webs of woven or non-woven materials of natural fibers (wood or cotton fibers ), synthetic fibers (polyester or polypropylene fibers), or a combination of natural and synthetic fibers. If the topsheet includes fibers, the fibers may be spunbonded, carded, wet laid, melt blown, hydroentangled, or otherwise processed known in the art. One such material, including cut length polypropylene fibers, is the P-8 material sold by Veratec, Inc., to the Division of International Paper Company of Walpole, MA., USA. Other alternative topsheets have been described in US 3,929,135; US-4,324,246; US-4,342,314; US 4,463,045; and US-5,006,394. Still other alternative topsheets can be manufactured according to US-4,609,518 and US-4,629,643. Films that can be used to make alternative topsheets may include DRI-WEAVE available from The Procter &amp; Gamble Company of Cincinnati, Ohio and CLIFF-T from Tredegar Corporation of Richmond, Virginia in the USA.

In certain embodiments, at least part of the topsheet is made of a hydrophobic material or has been treated to be hydrophobic to isolate the wearer's skin from the liquids contained in the absorbent core. If the topsheet is made of a hydrophobic material, preferably at least a portion of the upper surface of the topsheet is treated to be hydrophilic so that liquids transfer through the topsheet more quickly. The topsheet can be rendered hydrophilic by treating with a surfactant or incorporating a surfactant into the topsheet. Suitable methods of treating the topsheet with a surfactant include spraying the topsheet with the surfactant and / or dipping the material in the surfactant. A more detailed discussion of such treatment and hydrophilicity is included in, for example, US-4,988,344 and US-4,988,345. A more detailed discussion of some methods for incorporating a surfactant into the topsheet can be found in US Statutory Invention Registration No. H1670. Alternatively, the topsheet may include a band or apertured fabric that is hydrophobic. This can be accomplished by eliminating the hydrophilizing treatment step from the production process and / or applying a hydrophobic treatment to the topsheet, such as a polytetrafluroethylene compound such as the SCOTCHGUARD product sold by 3M Corporation of Minneapolis, Minnesota, USA. ., or a hydrophobic lotion composition. In such embodiments, it is preferred that the holes are large enough to allow penetration of aqueous fluids such as urine without significant resistance.

Other materials can be applied or incorporated into the topsheet. For example, any part of the topsheet can be coated with a lotion as is known in the art. Examples of suitable lotions include those described in US 5,607,760; US 5,609,587; US-5,635,191; US-5,643,588; US-5,968,025 and US-6,716,441. The lotion can work alone or in conjunction with another agent such as the hydrophobicizing treatment described above. The topsheet can also include or be treated with antibacterial agents, some examples of which have been described in PCT Publication No. WO 95/24173. Other possibilities will be recognized.

The backsheet can be made of a thin plastic film such as a thermoplastic film having a thickness of from about 0.012mm (0.5 mil) to about 0.051mm (2.0 mils). Illustrative backsheets include CPC2 film available from Tredegar Corporation of Richmond, Virginia, USA. Alternatively, the backsheet can be made of breathable materials, such materials allowing vapors to escape from the absorbent article while still preventing body exudates from passing through. Illustrative breathable materials may include woven webbing, nonwoven webbing, microporous films (such as ESPOIR film NOT available from Mitsui Toatsu Co. from Japan and EXAIRE film available from Tredegar Corporation of Richmond, Virginia, USA), and monolithic films (such as HYTREL P18-3097 blend available from Clopay Corporation of Cincinnati, Ohio, USA). Other alternative breathable materials may include composite materials, such as film-coated nonwoven webs or the composite materials described in PCT Publication No. WO 95/16746 and US-5,938,648; US-5,865,823; and US 5,571,096.

The absorbent core can have a wide variety of characteristics. For example, the core can be made in a variety of sizes and shapes (eg, rectangular, hourglass, T-shaped, asymmetric, etc.). In addition, the absorbent core can be manufactured from a wide variety of liquid absorbent materials that are commonly used in disposable diapers and other absorbent articles, such as diaper paste.

ES 2 453 045 T3 shredded wood, which is generally referred to as "air felt". Other suitable absorbent materials may include crimped cellulose wadding; melt blown polymers including shaped; chemically stiffened, modified or crosslinked cellulosic fibers; tissue paper, including tissue paper wrappers and tissue paper laminates; absorbent foams; absorbent sponges; superabsorbent polymers; absorbent gelling materials; or any other known absorbent material or combinations of materials. The configuration and structure of the absorbent core can also be varied: for example, the absorbent core or cores or other absorbent structure or structures can have zones of variable thickness, hydrophilic gradient (s), superabsorbent gradient (s), or uptake zones. low average density and low average grammage. Illustrative structures for use as the absorbent core may include those described in US-4,610,678; US-4,673,402; US-4,834,735; US-4,888,231; US 5,137,537; US-5,147,345; US-5,342,338; US 5,260,345; US5,387,207; and US-5,625,222.

The backsheet may be attached to the topsheet, absorbent core, or any other element of the absorbent article. In this way, the backsheet and topsheet may be attached directly to each other at some locations and indirectly at others, for example, by attaching them directly to one or more different elements of the absorbent article 120. The attachment can be formed of a variety of joining methods or mechanisms. For example, the attachment means or mechanisms may include a continuous and uniform layer of adhesive, a patterned layer of adhesive, or an arrangement of separate lines, spirals, or spots of adhesive. One possible bonding mechanism includes an open-design network of adhesive filaments, as in US 4,573,986. Another suitable bonding mechanism includes several lines of adhesive filaments that are interwoven in a spiral pattern, as in US 3,911,173; US-4,785,996; and US-4,842,666. Other adhesives that may be used are the HL-1620 and HL-1358-XZP adhesives available from the HB Fuller Company of St. Paul, Minnesota, USA In addition, alternative bonding mechanisms may include thermal bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other suitable bonding mechanism or combinations of these bonding mechanisms.

The topsheet may comprise one or more holes to facilitate penetration of exudates therethrough, such as urine and / or feces (solid, semi-solid, or liquid). When sizing the primary orifice, it is appropriate to note that if the primary orifice is too small, the debris may not pass through the opening, either due to misalignment of the debris source and the location of the opening. or because the fecal masses have a diameter greater than the orifice. Similarly, if the opening is too large, the area of ​​the skin that can be contaminated by "rewetting" from the article increases. Typically, the hole should have an area of ​​between approximately 10 cm² and about 50 cm². The hole preferably has an area of ​​between about 15 cm² and 35 cm².

In addition, the absorbent article may also include pockets to house and contain the waste, dividers that provide gaps for the waste, barriers to limit movement of the waste in the article, compartments or gaps that accept and contain waste materials deposited on the absorbent article 120. , and the like, or any combination thereof. Examples of pockets and dividers for use in absorbent products have been described in US Pat. No. 5,514,121; US-5,171,236; US-5,397,318; US 5,540,671; US6,168,584; US-5,306,266; and US-5,997,520. Examples of compartments or voids have been described in US Pat. No. 4,968,312; US 4,990,147; US 5,062,840; and US-5,269,755. Illustrative structures, including elasticated or trimmed topsheets, to provide a hollow space between the topsheet and the core have been described in more detail in US Pat. No. 4,892,536; US 4,990,147; US 5,037,416; and US-5,269,775. Examples of suitable transverse barriers have been described in US-5,554,142 and US-5,653,703; and in PCT Publication No. WO 94/14395. Examples of other structures especially suitable for managing low viscosity stools have been described in US Pat. No. 5,941,864; US-5,977,430 and US-6,013,063.

The absorbent article may include leg cuffs that provide improved containment of fluids and other body exudates. Leg cuffs can also be referred to as leg bands, side flaps, barrier cuffs, or elastic cuffs. Suitable folds may have been described in US-3,860,003; US 4,808,178; US 4,909,803; US-4,695,278; and US-4,795,454. In some embodiments, it may be desirable to treat all or a portion of the leg folds 32 with a lotion.

The absorbent article may also include an underlayer disposed between the topsheet and the backsheet. The underlayer can be any material or structure capable of accepting, storing or immobilizing body exudates. Thus, the sublayer may include a single material or a number of materials operatively associated with one another. Furthermore, the underlayer may be an integral part of another element of the diaper or it may be one or more separate elements attached directly or indirectly to one or more other elements of the diaper. Furthermore, the sublayer can include a structure that is separate from the core or can include or form part of at least a part of the core.

Suitable materials for use as an underlayer may include large cell open foams, compression resistant macroporous high recovery nonwovens, large particulate forms of closed cell and open cell foams (macroporous and / or microporous ), high recovery nonwovens, polyolefin, polystyrene, polyurethane foams or particles, structures comprising multiple strands with vertically oriented loops, absorbent core structures described above having punched holes or depressions and the like. One embodiment of a sublayer includes the element of

ES 2 453 045 T3 support for an XPL-7124 mechanical fastening loop having an uncompressed thickness of approximately

1.5 millimeters, sold by 3M Corporation of Minneapolis, Minnesota, USA Another embodiment includes a long fiber of 6 denier nonwoven, folded and bonded by resin, having a grammage of 110 grams per square meter and a 7.9 millimeter uncompressed thickness, available from The Glittering Company of Wrens, Georgia, USA Other suitable absorbent and non-absorbent underlayers have been described in US Pat. Nos. 6,680,422 and US5,941,864. Furthermore, the underlayer, or any part thereof, may include or be coated with a lotion or other known substances that add, enhance or change the capacity or other characteristics of the element.