KR20010085579A - Absorbent Article with Increased Wet Breathability - Google Patents

Abstract

The absorbent article includes a vapor permeable backsheet, a liquid permeable topsheet positioned face to face with the backsheet, and an absorbent body positioned between the backsheet and the topsheet. The absorber may comprise multiple zones of high air permeability or may comprise a material that provides improved ventilation after wetting. The absorbent article may also include a ventilation layer between the absorber and the backsheet, and a surge treatment layer between the absorber and the topsheet. The absorbent article exhibits improved ventilation in the absorbent article during use. As a result, the absorbent article exhibits a substantial reduction in the wearer's hydration when in use, allowing the skin to tolerate microbial growth.

Description

Absorbent Article with Increased Wet Breathability

Many known diaper types use an absorbent material located between the liquid permeable topsheet and the vapor and liquid impermeable backsheet. Such a backsheet is well suited to preventing liquid waste from moving from the absorbent material to the wearer's outer garment. Unfortunately, the use of liquid and vapor impermeable backsheets results in high humidity in the diaper upon use, which can increase the wearer's skin temperature, resulting in relatively high skin hydration levels. The closed and damp environment inside the diaper incorporating such a backsheet may promote the growth of microorganisms such as Candida albicans , which may lead to undesirable consequences of the development of diaper dermatitis (diaper rash). have.

Nearly all infants can suffer from diaper dermatitis at any time during the diaper wear period. The most severe form of these symptoms is usually caused by a secondary infection by Candida albicans bacteria. Although other factors influence the pathogenesis of this bacterium, one decisive factor is the relative humidity in the diaper, which is directly related to the closure or semi-closure of the diaper area.

In order to lower the humidity level in the diaper, a breathable polymer film was used as the outer cover of the absorbent garment, such as a disposable diaper. Breathable films are typically configured to have micropores that provide a desired level of liquid impermeability and air permeability. Other disposable diaper designs are breathable in the form of a breathable panel or perforated area in a vapor impermeable backsheet to assist in ventilating the garment. It is arranged to provide an area.

Conventional absorbent articles as described above were not completely satisfactory. For example, absorbent articles using perforated films or breathable panels may exhibit excessive leakage of liquid from the absorbent articles and may excessively soil the wearer's outer garment in the perforated or panel area. In addition, when a liquid is dropped into the absorbent material of the absorbent article, the wet absorbent body can prevent the moisture from releasing from the wearer's skin. This absorbent garment design could not maintain high levels of breathability when wet and could not sufficiently reduce hydration of the wearer's skin. Thus, the wearer's skin is subject to rash, peeling and irritation.

Summary of the Invention

In response to the difficulties and problems discussed above, a new disposable absorbent article has finally been found that has a high rate of ventilation when wet and consequently a reduced level of skin hydration.

As used herein, the term “ventilation” means that air, in particular moist air, is transferred from the inside of the diaper to the outside of the diaper (ambient atmosphere) while worn and used by the wearer so that the dry ambient air is moved into the absorbent article.

Substantially liquid impermeable material as used herein is configured to provide a hydrohead of at least about 60 cm, preferably at least about 80 cm, more preferably at least about 100 cm. A suitable technique for determining the hydrohead value is a fluid hydrostatic test, described in detail below.

As used herein, a substantially vapor permeable material has a water vapor transfer rate (WVTR) of at least about 100 g / m 2 / 24h, preferably at least about 250 g / m 2 / 24h, more preferably at least about 500 g / m 2 / 24h. It is configured to provide. A suitable technique for determining the WVTR value is the water vapor transfer rate test described in detail below.

In one aspect, the invention relates to an absorbent article comprising an absorbent body, an anterior waist region, a posterior waist region, and an intermediate region connecting the anterior waist region and the posterior waist region. This absorbent article is defined as having a ventilation rate of wetness of about 190 cc / min or more calculated according to the Tracer Gas Test described herein. In certain embodiments, the absorbent article is defined as having a ventilation rate of wetting at least about 200 cc / min, preferably at least about 225 cc / min, more preferably at least about 250 cc / min, calculated according to the tracer gas test. In addition, the absorbent article has a dryness ventilation rate of about 525 cc / min or more calculated according to the tracer gas test, and / or a skin hydration degree of less than about 18 g / m 2 / h calculated according to the skin hydration test described herein. It can be defined as.

As another feature, the invention relates to a disposable absorbent article comprising an absorbent body, an anterior waist region, a posterior waist region, and an intermediate region connecting the anterior waist region and the posterior waist region. This absorbent article is defined as a degree of skin hydration calculated according to the skin hydration test described herein. In certain embodiments, the absorbent article has a skin hydration calculated according to the skin hydration test of less than about 15 g / m 2 / h, preferably less than about 12 g / m 2 / h, more preferably about 10 g / m 2 / h. It can be defined as less than. In addition, an absorbent article may be defined with a ventilation rate of wetness of at least about 190 cc / min and / or a drying rate of drying of at least about 525 cc / min, calculated according to the tracer gas test described herein.

As another feature, the present invention relates to a disposable absorbent article defining an anterior waist region, a posterior waist region, and an intermediate region connecting the anterior waist region and the posterior waist region. This absorbent article comprises: a) a vapor permeable backsheet with a vapor transmission rate defined according to the water vapor delivery test described herein, defined as at least about 1000 g / m 2 / 24h, b) a liquid permeable topsheet positioned facing the back sheet. And, c) an absorber that can define multiple zones with high air permeability for improved ventilation and is located between the backsheet and the topsheet. In one particular embodiment, the zone of high air permeability in the absorber is defined as a Fraser porosity that is at least about 10% greater than the Frazier Porosity of the portion of the absorber adjacent to the zone of high air permeability. The absorbent article may also include a ventilation layer located between the backsheet and the absorbent body.

As another feature, the present invention relates to a disposable absorbent article defining an anterior waist region, a posterior waist region, and an intermediate region connecting the anterior waist region and the posterior waist region. This absorbent article comprises: a) a vapor permeable liquid impermeable backsheet, defined by a water vapor transfer rate test described herein, defined as at least about 1000 g / m 2 / 24h, b) a liquid positioned to face the back sheet. A permeable topsheet, c) an absorber located between the backsheet and the topsheet, d) a ventilation layer located between the backsheet and the absorbent, and e) a surge treatment layer located between the topsheet and the absorbent. In one particular embodiment, the absorbent article of the absorbent article comprises a plurality of zones of high air permeability for improved ventilation, the zones of high air permeability being at least about 10% greater than the Frasiness of the absorber portion adjacent to this zone. Fraser porosity is defined.

As another feature, the invention relates to a disposable absorbent article comprising an absorbent body, an anterior waist region, a posterior waist region, and an intermediate region connecting the anterior waist region and the posterior waist region. This absorbent article is defined as a ratio of wet to dry / vented to dry calculated in accordance with the tracer gas test described herein at least about 0.50.

In another aspect, the present invention provides a liquid permeable top positioned face to face with a vapor permeable backsheet, backsheet, wherein the water vapor delivery rate calculated according to the water vapor delivery test described herein is defined as about 1000 g / m 2 / 24h or more. And an absorbent body positioned between the back sheet and the top sheet. The absorbent article is defined as a wet-to-wet ventilation rate / dry-to-dry ventilation ratio ratio calculated according to the tracer gas test described herein at least about 1.00, preferably at least about 1.05, more preferably at least about 1.10.

As another feature, the invention relates to a disposable absorbent article comprising an anterior waist region, a posterior waist region, and an intermediate region connecting the anterior waist region and the posterior waist region. This absorbent article includes a vapor backsheet, a liquid permeable topsheet positioned facing the backsheet, and a backsheet, wherein the water vapor transmission rate calculated according to the water vapor permeation test described herein is defined as at least about 1000 g / m 2 / 24h. And an absorbent positioned between and the topsheet, wherein at least a portion of the absorbent shrinks about 5%, preferably about 10%, in at least one of the machine direction and the machine cross direction when exposed to water vapor or moisture. In some embodiments, the absorbent body comprises a plurality of segments, and the contraction of the absorber provides a zone of high air permeability between the segments.

In certain embodiments, the absorbent article has a ventilation ratio on wet / ventilation ratio on drying of about 0.70 or more, preferably about 0.80 or more, more preferably about 0.90 or more, even more preferably about 1.00 or more, even more preferably about 1.10 or more. Is defined.

In some embodiments, the absorbent article also has a skin hydration calculated according to the skin hydration test described herein, less than about 18 g / m 2 / h, preferably less than about 15 g / m 2 / h, more preferably about Less than 12 g / m 2 / h, even more preferably less than about 10 g / m 2 / h.

The absorbent article may further include a ventilation layer positioned between the backsheet and the absorbent for improved ventilation and / or further include a surge treatment layer between the topsheet and the absorbent.

The present invention advantageously provides an improved absorbent article that substantially reduces the wearer's skin hydration level during use compared to conventional absorbent articles. Reduced skin hydration levels promote drier and more comfortable skin and make the skin less sensitive to the growth of microorganisms. Thus, wearers of absorbent articles made according to the invention have reduced skin hydration and more constant skin temperature in use, which can reduce the occurrence of skin irritation and rash and result in improved skin health.

The present invention relates to an absorbent article for absorbing body fluids and secretions such as urine. More specifically, the present invention relates to absorbent garments, such as disposable diapers and adult incontinence garments, which are configured to absorb body secretions while also providing reduced skin hydration and increased skin health.

The present invention will be more fully understood upon reading the detailed description of the invention and the accompanying drawings, which will be apparent from the following, and will clearly see further advantages.

1 representatively illustrates a partially cut away plan view of an absorbent article according to one embodiment of the present invention.

2 representatively illustrates a cross-sectional view of the absorbent article of FIG. 1 taken along line 2-2.

3 representatively illustrates a partially cut away plan view of an absorbent body of an absorbent article according to another embodiment of the present invention.

4 representatively illustrates a cross-sectional view of the absorbent body of FIG. 3 taken along line 4-4.

5 representatively illustrates a partially cut away plan view of an absorbent body of the absorbent article according to another embodiment of the present invention.

6 representatively illustrates a cross-sectional view of the absorbent body of FIG. 5 taken along lines 6-6.

7 representatively shows a graph of the data of Example 15 and Comparative Example 6. FIG.

The following description will be described in conjunction with disposable diaper products suitable for wearing on the lower torso of an infant. However, it is readily understood that the absorbent articles of the present invention may also be suitable for use as other types of absorbent articles, such as women's sanitary napkins, incontinence garments, training pants, and the like.

The absorbent articles of the present invention advantageously exhibit improved breathability which substantially reduces the wearer's skin hydration level during use compared to conventional absorbent articles. The absorbent articles of the present invention may further maintain a more constant wearer skin temperature when wet as compared to conventional absorbent articles. Thus, it is possible to reduce the occurrence of dermatitis and rashes by reducing skin hydration which makes the absorbent articles of the various features of the present invention less susceptible to the growth of microorganisms. It has been found that the ability of an absorbent article of the present invention to exhibit low levels of hydration on the wearer's skin during use depends, at least in part, on the ability of the absorbent article to achieve high ventilation rates in the absorbent article. In addition, the achievement of such low skin hydration levels has also been found to depend on the absorbent's ability to maintain or increase high ventilation rates even when wet.

For the purposes of the present application, the ability of an absorbent article to achieve high ventilation rates during drying and wetting was quantified as the drying ventilation rate, wet ventilation rate and wet ventilation rate / wetting ventilation rate ratio as determined by the tracer gas test described below. . In brief, the tracer gas test involves injecting the tracer gas at a constant rate inside the absorbent side next to the wearer's skin while wearing the absorbent article. At the same time, the concentration of tracer gas in the space between the absorbent article and the wearer is measured by withdrawing the sample at the same rate as the injection. The ventilation rate is then determined based on the mass balance of air and tracer gas in the space in question.

In order to achieve the desired low skin hydration level, the absorbent articles of the various features of the present invention are at least about 190 cc / min, generally at least about 200 cc / min, preferably at least about 225 cc / min, more preferably It can be configured to define a ventilation rate when wet at least about 250 cc / min, even more preferably at least about 300 cc / min. For example, the absorbent article may define a rate of ventilation on wet of about 175 to about 1500 cc / min, preferably about 225 to about 1500 cc / min. Absorbents whose wetting rate is lower than the values described above do not allow a sufficient amount of ventilation, which results in undesirable consequences of increased skin hydration levels. This increased skin hydration level may allow the skin to further allow the growth of microorganisms, which may result in undesirable consequences of increasing the occurrence of skin irritation and rashes.

The absorbent articles of the various features of the present invention are configured to define a ventilation rate / wetting rate ratio on drying for at least about 0.20, generally at least about 0.23, preferably at least about 0.27, more preferably at least about 0.30 for improved performance. Can be. In certain embodiments, the absorbent articles of the various features of the present invention have a ventilation ratio on wet / dry ventilation ratio of at least about 0.50, generally at least about 0.70, preferably at least about 0.80, more preferably at least about 0.90 for improved performance. It is configured to define. In certain other embodiments, the absorbent articles of the various features of the present invention are configured to define a ventilation ratio on wet / dry ventilation ratio of at least about 1.00, generally at least about 1.05, preferably at least about 1.10 for improved performance. For example, the absorbent article may have an air permeability / wetting rate of from about 0.20 to about 2.00, preferably from about 0.50 to about 2.00, more preferably from 0.70 to about 2.00, even more preferably from about 1.00 to about 2.00 for improved performance. The rate of ventilation at drying can be defined. An absorbent article that defines a high wetting ventilation rate / drying ventilation ratio ratio as above provides improved ventilation when needed most, ie when the article is wet.

In addition, the absorbent articles of the various features of the present invention are at least about 525 cc / min, generally at least about 575 cc / min, preferably at least about 625 cc / min, more preferably about 675 cc / min for improved performance. It may be configured to define a ventilation rate upon drying of at least minutes, even more preferably at least about 750 cc / minute. For example, the absorbent article may define a ventilation rate upon drying of about 525 to about 2500 cc / min, preferably about 575 to about 2500 cc / min. Absorbents whose drying rate is lower than the values described above do not allow sufficient amount of ventilation, which results in undesirable consequences of increased skin hydration levels. Such increased skin hydration levels may allow the skin to further allow the growth of microorganisms, which may have undesirable consequences of increasing the occurrence of skin irritation and rashes.

Alternatively, in embodiments in which the absorbent article defines a relatively high wet rate / dry rate of ventilation ratio, it may not be necessary for the article to provide the above mentioned dry rate of ventilation to achieve improved performance. For example, in embodiments in which the absorbent article defines a ventilation rate / wetting rate ratio when wet / dry, at least about 0.50, preferably at least about 0.70, more preferably at least about 0.80, even more preferably at least about 0.90. In order to improve performance, including improved skin hydration and improved skin health, the absorbent article may have a ventilation rate upon drying of at least about 200, preferably at least about 225, more preferably at least about 250, even more preferably at least about 300 cc / min. Can be defined

Improved ventilation in the absorbent articles of the present invention reduces the wearer's skin temperature when worn. For the purposes of the present application, the ability of the absorbent article to maintain a more constant skin temperature upon wetting was quantified by the skin temperature on wet / skin temperature on drying determined according to the skin temperature test described below. In brief, the skin temperature test involves placing the absorbent article to be tested around the forearm of the subject and measuring the skin temperature below the absorbent article before and after wetting the absorbent article with a known amount of saline solution. Skin temperature at drying is recorded after wearing the dry absorbent for 5 minutes. The absorbent article is then wetted and the wetted absorbent article is worn for 120 minutes before recording the skin temperature upon wetting.

Absorbent articles of various aspects of the present invention have a wetness of about 1.010 or less, generally about 1.005 or less, preferably about 1.000 or less, more preferably about 0.995 or less, even more preferably about 0.990 or less for improved performance. It can be configured to define the skin temperature ratio upon skin temperature / drying. For example, an absorbent article may define a skin temperature on wet / skin temperature on dry ratio of about 0.950 to about 1.010, preferably about 0.970 to about 1.005, for improved performance. Skin temperature when wet / Skin temperature when dry Non-absorbents do not maintain skin temperature when wet, which may allow the skin to tolerate microbial growth, thus increasing the occurrence of skin irritation and rashes. May result in inadequate results.

The ability of the absorbent articles of the present invention to exhibit more constant skin temperature and higher levels of ventilation when dry and wet resulted in reduced skin hydration levels. For the purposes of the present application, the ability of the absorbent to achieve low skin hydration levels was quantified as skin hydration. As used herein, the term "skin hydration" means a value determined according to the skin hydration test described below. Generally, the degree of skin hydration is determined by measuring the evaporation moisture loss on the subject's skin after wearing a wetted absorbent article for a period of time. In certain embodiments, the absorbent articles of the various features of the present invention are less than about 18 g / m 2 / h, generally less than about 15 g / m 2 / h, preferably less than about 12 g / m 2 / h, for improved performance, More preferably less than about 10 g / m 2 / h, even more preferably less than about 8 g / m 2 / h, even more preferably less than about 5 g / m 2 / h. Can be. For example, the absorbent articles of the present invention may define a degree of skin hydration of about 0.1 to about 18 g / m 2 / h, preferably about 0.1 to about 12 g / m 2 / h. Absorbents whose skin hydration is greater than the values described above may allow the skin to tolerate microbial growth, which may result in undesirable consequences of increasing the occurrence of skin irritation and rashes.

Improved wet and dry ventilation rates of the absorbent articles of the present invention may further reduce dermatitis by reducing the growth rate of microorganisms. The reduction in microbial viability is assumed to be a direct result of increased breathability and ventilation in the absorbent articles of the present invention. Since it is assumed that the presence of Candida albicans is directly related to the increase in stimulation, especially rash, the ability of the absorbent to achieve low microbial growth was quantified as Candida albicans viability. As used herein, the term “candida albicans growth” refers to a value determined according to the Candida albicans growth test described below. In general, the Candida albicans viability test showed the growth of Candida albicans under a control patch of a conventional absorbent article having a non-breathable outer cover, i.e., an outer cover with a WVTR of less than 100 g / m2 / 24h. It is to compare viability.

In certain embodiments, the absorbent articles of the various features of the invention are less than about 85%, generally less than about 80%, preferably less than about 60%, more preferably less than Candida albicans viability of the control group for improved performance. It may be configured to define Candida albicans viability of less than about 40%, even more preferably less than about 20%. For example, the absorbent article of the present invention is less than about 2.5 log, preferably less than about 2.0 log, more preferably when inoculated with a suspension of about 5-7 log of Candida albicans colony forming units according to the Candida albicans growth test. Preferably, Candida albicans growth of less than about 1.75 log of Candida albicans colony forming units can be defined. Absorbents with Candida albicans viability values greater than those described above can lead to undesirable consequences of increasing the occurrence of skin irritation and rashes.

Preferably, the Candida albicans growth value is obtained without incorporation of an antimicrobial agent into the absorbent article which can be perceived negatively by the consumer.

Allowed and improved performance of the absorbent article can be achieved by selecting a configuration having one or more combinations of these properties. For example, a given level of acceptable and improved performance can be achieved by using absorbent articles that exhibit a ventilation rate of wetting of at least about 190 cc / min and a ventilation rate of wetting / drying of at least about 0.50, preferably at least about 1.00. Can be. Alternatively, acceptable improved performance can be achieved by using an absorbent article that exhibits a dry rate on wetting of at least about 190 cc / min and a skin hydration of less than about 18 g / m 2 / h.

It can also be achieved by using an absorbent article having a vapor permeable backsheet, wherein the WVTR is at least about 1000 g / m 2 / 24h and the wetness rate / dryness rate is defined as at least about 0.50, preferably at least about 1.00. Found. Alternatively, the acceptable improved performance can be achieved with a water vapor permeable backsheet having a WVTR of at least about 1000 g / m 2 / 24h and an absorber with at least some shrinkage in one of the machine direction and the machine cross direction when exposed to water vapor or moisture. It can be achieved by using a product.

Examples of absorbent articles having a suitable configuration for use in the present invention are shown below and are representatively illustrated in FIGS. 1 to 6. 1 is a representative plan view of an integral absorbent garment product, such as the disposable diaper 10 of the present invention in a flat unfolded state (ie, all elastically induced gathering and shrinkage removed). Some of the parts of the structure are cut away to more clearly show the internal configuration of the diaper 10, with the surface of the diaper in contact with the wearer facing the viewer. 2 representatively shows a cross-sectional view of the absorbent article of FIG. 1 taken along line 2-2. In FIGS. 1 and 2, disposable diaper 10 generally defines an anterior waist region 12, a posterior waist region 14, and an intermediate region 16 connecting the anterior waist region and the posterior waist region. do. The anterior waist region and the posterior waist region each comprise general portions of an absorbent article configured to substantially span around the front and back of the wearer's abdominal region, respectively. The middle section of the absorbent article includes the general portions of the absorbent article configured to span through the crotch region between the wearer's legs.

The absorbent article may include an absorbent material such as a vapor permeable backsheet 20, a liquid permeable topsheet 22 positioned in front of the backsheet 20, and an absorbent pad disposed between the backsheet 20 and the topsheet 22 ( 24). The backsheet 20 is defined by length and width, which matches the length and width of the diaper 10 in the illustrated embodiment. Absorber 24 generally defines a length and width that are less than the length and width of backsheet 20, respectively. Thus, the edge portions of the diaper 10, such as the edge region of the backsheet 20, may extend beyond the distal edge of the absorber 24. In the illustrated embodiment, for example, the backsheet 20 extends outward beyond the distal edge edge of the absorbent 24 to form the lateral and distal edges of the diaper 10. Topsheet 22 is generally the same dimension as backsheet 20, but may optionally span an area larger or smaller than the area of backsheet 20, as desired. The backsheet 20 and topsheet 22 are intended to face the wearer's garment and body, respectively, during use.

The permeability of the backsheet enhances the breathability of the absorbent article to prevent excessive condensation of vapor, such as urine, on the garment-side surface of the backsheet 20, which can result in undesirable consequences of dampening the wearer's clothing. In order to reduce wearer's skin hydration during use.

In order to provide improved fit and to reduce body secretion leakage from the diaper 10, the diaper side edges and distal edges can be elasticized with suitable elastic members, such as single or multiple elastic strands. The elastic strands may be made of natural or synthetic rubber and may optionally be heat shrinkable or thermoelastic. For example, as representatively illustrated in FIGS. 1 and 2, the diaper 10 is operably gathered and shirred on the side edges of the diaper 10 to fit snugly around the wearer's leg for leaks. Leg elastics 26 configured to provide an elasticized leg band that can reduce and provide improved comfort and appearance. Likewise, waist elastic 28 can be used to elasticize the distal edge of diaper 10 to provide an elasticized waist. The waist elastics are configured to steerably gather and shear the waist region to provide a resilient and comfortable fit that fits snugly around the wearer's waist. In the illustrated embodiment, for the purpose of clarity, the elastic member is illustrated in an elongated state without contraction.

Fastening means such as hook and loop fasteners 30 are used to secure the diaper to the wearer. Alternatively, other fastening means may be used, such as buttons, pins, snaps, adhesive tape fasteners, adhesives, mushroom-and-loop fasteners, and the like.

In addition, the diaper 10 may include other layers between the absorbent body 24 and the topsheet 22 or backsheet 20. For example, as representatively illustrated in FIGS. 1 and 2, the diaper 10 isolates the backsheet 20 from the absorber 24 to improve air circulation and the garment side of the backsheet 20. It may include a breathing layer 32 positioned between the absorbent body 24 and the backsheet 20 to effectively reduce the dampness of the surface. In addition, the ventilation layer 32 can assist in dispensing fluid secretions to portions of the absorbent body 24 that do not directly receive secretions. In addition, the diaper 10 may include a surge treatment layer 34 positioned between the topsheet 22 and the absorber 24 to prevent the fluid secretion from pooling and to further improve ventilation and fluid secretion distribution in the diaper 10. It may include.

The diaper 10 may be of various suitable shapes. For example, the diaper can be an overall rectangular, T-shaped, or approximately hourglass type. In the embodiment shown, the diaper 10 has a general I-shaped shape. In addition, the diaper 10 defines a longitudinal direction 36 and a transverse direction 38. Other suitable diaper components that can be incorporated into the absorbent articles of the present invention include containment flaps, waist flaps, elastomeric side panels, and the like, generally known to those skilled in the art.

Examples of diaper configurations suitable for use in connection with the present application that may include other diaper components suitable for use in a diaper are described in US Pat. No. 4,798,603 to Meyer et al., Issued January 17, 1989. , US Patent No. 5,176,668 to Bernardin (January 5, 1993), US Patent No. 5,176,672 to Brummer et al. (January 5, 1993), Prox US Pat. No. 5,192,606 to Proxmire et al., Issued March 9, 1993; and US Pat. No. 5,509,915 to Hanson et al., Issued April 23, 1996, The contents of these documents are incorporated herein by reference.

The various components of the diaper 10 are assembled together to be united using various kinds of suitable attachment means such as adhesives, sonic bonds, thermal bonds or a combination thereof. In the illustrated embodiment, for example, the topsheet 22 and the backsheet 20 are assembled with each other and the absorber 24 in an adhesive strip, such as a hot melt pressure sensitive adhesive. Likewise, other diaper components, such as elastic members 26 and 28, fastening member 30, vent layer 32, and surge layer 34, can also be assembled into the diaper product using the attachment mechanism. .

As representatively illustrated in FIGS. 1 and 2, the backsheet 20 of the diaper 10 is substantially made of a vapor permeable material. The backsheet 20 is generally configured to be at least permeable to water vapor, at least about 1000 g / m 2 / 24h, preferably at least about 1500 g / m 2 / 24h, more preferably at least about 2000 g / m 2 / 24h, Even more preferably have a water vapor delivery rate of at least about 3000 g / m 2 / 24h. For example, the backsheet 20 may define a water vapor transfer rate of about 1000 to about 6000 g / m 2 / 24h. Substances whose water vapor transfer rate is less than the values described above do not allow sufficient amount of ventilation, leading to undesirable consequences of increased skin hydration levels.

In addition, the backsheet 20 is preferably substantially liquid impermeable. For example, the backsheet may be configured to provide a hydrohead value of at least about 60 cm, preferably at least about 80 cm, more preferably at least about 100 cm when tested by a hydrostatic test. Substances with hydrohead values lower than those described above have the undesirable consequence of penetrating a liquid such as urine during use. This fluid penetration can have undesirable consequences of giving the backsheet 20 a damp and sticky feel during use.

The backsheet 20 may be made of a suitable material that directly provides the desired level of liquid impermeability and air permeability, or, alternatively, a material that can be modified or treated in some way to provide this level. In one embodiment, the backsheet 20 may be a nonwoven fibrous web configured to provide the required level of liquid impermeability. For example, a nonwoven web of spunbonded or meltblown polymer fibers may be optionally treated with a water repellent coating or laminated with a liquid impermeable vapor permeable polymer film to provide the backsheet 20. In certain embodiments of the present invention, the backsheet 20 is a plurality of randomly deposited hydrophobic thermoplastic meltblown fibers sufficiently bonded or otherwise interconnected to provide a substantially vapor permeable and substantially liquid impermeable web. It may be made of a nonwoven web. The backsheet 20 may also be characterized as including a vapor permeable nonwoven layer that is partially coated or otherwise configured to provide liquid impermeability to selected areas.

Further examples of suitable materials for the backsheet 20 are described in US Pat. No. 5,482,765 to Bradley et al., Issued Jan. 9, 1996; titled “NONWOVEN FABRICLAMINATE WITH ENHANCED BARRIER PROPERTIES”, U.S. Patent Application No. 08 / 622,903, filed March 29, 1996; name of the invention: “ABSORBENT ARTICLE HAVING A BREATHABLE GRADIENT, Good, et al. 08 / 668,418 (filed June 21, 1996; titled “ABSORBENT ARTICLE HAVING A COMPOSITE BREATHABLE BACKSHEET”), and US Patent Application No. 08 / 882,712 to McCormack et al. (June 1997) Filed 25 days; entitled “LOW GAUGE FILMS AND FILM / NONWOVEN LAMINATES”, the disclosures of which are incorporated herein by reference.

In certain embodiments, the backsheet 20 is provided by a microporous film / nonwoven laminate material made of a spunbond nonwoven material laminated to the microporous film. The spunbond nonwoven material consists of about 1.8 denier filaments extruded from a copolymer of ethylene and about 3.5 weight percent propylene and defines a basis weight of about 17 to about 25 g / m 2. The film consists of a template coextruded film with calcium carbonate particles and defines a basis weight before stretching of about 58 g / m 2. The film is preheated, stretched and annealed to form micropores and then laminated to the spunbond nonwoven material. The microporous film / nonwoven laminate based material obtained has a basis weight of about 30 to about 60 g / m 2 and a water vapor transmission rate of about 3000 to about 6000 g / m 2 / 24h. Examples of such film / nonwoven laminate materials are described in more detail in U.S. Patent Application No. 08 / 882,712 filed June 25, 1997; titled “LOW GAUGE FILMS AND FILM / NONWOVEN LAMINATES” of McCormack et al. The contents of this document are incorporated herein by reference.

As representatively illustrated in FIGS. 1 and 2, the topsheet 22 suitably provides a comfortable, soft feel to the wearer's skin and provides a non-irritating body surface. In addition, the topsheet 22 may be less hydrophilic than the absorbent 24 to provide the wearer with a relatively dry surface, and may be porous enough to be liquid permeable, allowing liquid to easily penetrate through thickness. Suitable topsheets 22 can be porous foams, reticulated foams, perforated plastic films, natural fibers (eg wood or cotton fibers), synthetic fibers (eg polyester or polypropylene fibers), or natural and synthetic It can be made from a wide range of web materials, such as combinations of fibers. Topsheet 22 is suitably used to help isolate the wearer's skin from the liquid retained in absorbent 24.

Various woven and nonwoven fabrics can be used for the topsheet 22. For example, the topsheet may consist of a meltblown or spunbonded web of polyolefin fibers. The topsheet may also be a bonded-carded web of natural and / or synthetic fibers. The topsheet may be made of substantially hydrophobic material, and the hydrophobic material may optionally be treated with a surfactant or otherwise processed to impart the desired level of wettability and hydrophilicity. In certain embodiments of the present invention, the topsheet 22 is a nonwoven spunbond polypropylene fabric composed of about 2.8 to 3.2 denier fibers, formed from a web having a basis weight of about 22 g / m 2 and a density of about 0.06 g / cm 3. Is done. This topsheet 22 has an effective amount of about 0.3% by weight of a surfactant commercially available from Hodson Textile Chemicals Co. under the tradename AHCOVEL BASE N-62. It can be surface treated with a surfactant.

As representatively illustrated in FIGS. 1 and 2, the absorbent body 24 of the diaper 10 is a matrix of hydrophilic fibers, such as a web of cellulose fluff, mixed with particles of a superabsorbent material, commonly known as a superabsorbent material. It can be made as appropriate. In certain embodiments, absorbent 24 consists of a matrix of cellulose fluff, such as wood pulp fluff, and superabsorbent hydrogel forming particles. Wood pulp fluff can be replaced with synthetic polymer meltblown fibers or with a mixture of meltblown fibers and natural fibers. The superabsorbent particles may be mixed substantially homogeneously with the hydrophilic fibers or may be mixed heterogeneously. Alternatively, the absorbent body 24 may consist of a laminate of the fibrous web and the superabsorbent material or other suitable means of retaining the superabsorbent material in the localized region.

The absorber 24 may be any shape among many shapes. For example, the absorbent core can be rectangular, I-shaped or T-shaped. In general, the absorbent body 24 is preferably narrower in the middle region than in the front or rear waist region of the diaper 10. The absorber 24 may be provided in a single layer or, alternatively, may be provided in multiple layers where not all layers need to extend to the full length and width of the absorber 24. In certain aspects of the invention, for improved performance, in particular for boys, the absorber 24 may generally be T-shaped, with a transversely extending crossbar of “T” generally providing an anterior waist region 12 of the absorbent article. Corresponds to. In the illustrated embodiment, for example, the absorbent body 24 across the front waist region 12 of the absorbent article has a transverse width of about 18 cm, and the narrowest portion of the middle region 16 is about 7.5 cm It is wide and has a width of about 11.4 cm in the posterior lumbar region.

The size and absorbent capacity of the absorbent body 24 should be compatible with the liquid load imposed by the intended wearer's physique and the intended use of the absorbent article. In addition, the size and absorbent capacity of the absorber 24 can be varied to accommodate the wearer from infant to adult. It has also been found that, by the present invention, the density and / or basis weight of the absorber 24 can be varied. In certain aspects of the invention, absorbent 24 has an absorbent capacity of at least about 300 g of synthetic urine.

In embodiments in which the absorbent 24 comprises a mixture of hydrophilic fibers and superabsorbent particles, the hydrophilic fibers and superabsorbent particles may form an average basis weight of the absorbent 24 of about 400 to 900 g / m 2. . In some aspects of the invention, the average composite basis weight of such absorbent 24 to provide the desired performance is about 500 to 800 g / m 2, preferably about 550 to 750 g / m 2.

In order to provide the desired thin dimensions for the absorbent articles of the various configurations of the present invention, the absorbent body 24 may be configured to have a bulk thickness of about 0.6 cm or less. Preferably, the bulk thickness is about 0.53 cm or less, more preferably about 0.5 cm or less for improved performance. Bulk thickness is determined under a suppression pressure of 1.38 kPa (0.2 psi).

Superabsorbent materials can be selected from natural, synthetic, and modified natural polymers and materials. The superabsorbent material may be an inorganic material such as silica gel, or an organic compound such as a crosslinked polymer. The term "crosslinked" refers to any means by which a material that is normally water soluble is effectively substantially water insoluble but water swellable. Such means may include, for example, physical entanglement, crystalline domains, covalent bonds, ion complexes and associations, hydrophilic associations such as hydrogen bonds, and hydrophobic associations or van der Waals forces.

Examples of synthetic polymer superabsorbent materials include alkali metal and ammonium salts of poly (acrylic acid) and poly (methacrylic acid), poly (acrylamide), poly (vinylether), vinylether and alpha olefins with copolymers of maleic anhydride, Poly (vinyl pyrrolidone), poly (vinyl morpholinone), poly (vinyl alcohol), and mixtures and copolymers thereof. Additional polymers suitable for use in the absorbent core include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and alginate, xantham gum, locust bean gum. Natural and modified natural polymers such as natural gums, and the like. In addition, mixtures of natural and total or partially synthetic absorbent polymers may also be useful in the present invention.

The superabsorbent material may be any of a wide variety of geometric shapes. As a general rule, the superabsorbent material is preferably in the form of individual particles. However, the superabsorbent material may also be in the form of fibers, flakes, rods, spheres, needles and the like. Generally, the superabsorbent material is present in the absorbent in an amount of about 1 to about 90 weight percent, preferably at least about 30 weight percent, even more preferably at least about 50 weight percent, based on the total weight of the absorbent 24. . For example, in certain embodiments, absorbent 24 comprises at least about 50% by weight, preferably at least about 70% by weight, of superabsorbent material wrapped by a fibrous web or other suitable means of retaining the superabsorbent material in a localized region. It may be made of a laminate comprising.

An example of a suitable superabsorbent material for use in the present invention is Sanwet IM 3900 available from Hoechst Celanese (Portsmouth, Va.). Other suitable superabsorbent materials may include W45926 or FAVOR SXM 880 polymers obtained from Stockhausen (Greensboro, North Carolina, USA).

Optionally, a substantially hydrophilic tissue wrapsheet (not shown) can be used to help maintain the integrity of the structure of the absorber 24. Typically, the tissue wrapsheet lies around at least two major surfaces of the absorbent body and consists of an absorbent cellulosic material, such as creped wedding or high wet strength tissue. As a feature of the present invention, the tissue wrap may be configured to provide a wicking layer to help disperse liquid quickly into the absorbent fiber mass that constitutes the absorbent body.

The material in the absorbent may also be configured to provide a higher level of breathability when wet. For example, the absorbent 24 may comprise a material which, when exposed to moisture or water vapor, contracts the absorbent 24 or at least a portion thereof in the x-y plane, ie in the machine direction and / or machine cross direction. The term "machine direction" as used herein refers to the direction in which the absorbent article is moved during manufacture, and the term "machine cross direction" refers to a direction perpendicular to the machine direction. This shrinkable absorber 24 or at least part of it can be shrunk in either the machine direction or the machine cross direction to improve performance, or the absorber 24 or at least part thereof is shrunk in both the machine direction and the machine cross direction. do. Shrinkage of the absorbent 24 or at least a portion thereof for improved ventilation in the article will reduce the surface area of the absorbent contacting the backsheet and the topsheet of the article, thereby exposing more vapor permeable backsheet.

In one particular embodiment, the absorbent article 24 may include a material that causes the absorbent 24 or at least a portion thereof to shrink in the machine direction and / or the machine cross direction when exposed to water vapor. Shrinkage of the absorbent body 24 or a portion thereof can be suitably controlled to provide the desired breathability when wet. For improved performance, the absorbent body 24 or at least a portion thereof is at least about 5%, preferably in at least one of the machine direction or the machine cross direction when exposed to normal relative humidity in an absorbent article such as a baby diaper during use. Can shrink at least about 10%, more preferably at least about 30%, even more preferably at least about 50%. For example, the absorbent 24 or at least a portion thereof may shrink from about 5% to about 80%, preferably from about 30% to about 50% in one or more of the machine direction or the machine cross direction in use.

Such shrinking absorbent materials may be incorporated into the absorbent body 24 of various aspects of the invention in a variety of suitable ways. For example, absorbent 24 is a shrinkable absorbent material above or below a layer of conventional absorbent material having pores thereon such that the shrinkable absorbent layer contracts for improved breathability when wetted upon exposure to water vapor and exposes pores in the conventional layer. It may include a layer of. Alternatively, absorbent 24 may include a layer of shrinkable absorbent material that is segmented such that when exposed to water vapor the segment shrinks, thereby creating more opening area for improved ventilation. Suitable arrangements of segments are discussed in more detail below.

In another embodiment, the absorbent body 24 includes a highly breathable absorbent material that includes a highly breathable zone 42 that increases in size so that the remaining portion of the absorber contracts when exposed to water vapor to increase the opening area and improve ventilation. It may be made of. In another alternative embodiment, the shrinkable absorbent material piece may be mixed and form a conventional absorbent body upon exposure to water vapor to shrink the shrinkable absorbent piece to create an opening area in a conventional absorbent structure. In another alternative embodiment, the absorbent 24 is optionally slitted to reduce the opening area for improved ventilation without the contraction of the absorbent 24 upon exposure to water vapor substantially affecting the overall dimensions of the absorbent 24. The slit is attached to the absorbent article to widen and produce.

Materials suitable for providing such shrinkable absorbent materials may include meltblown materials, coform materials, air-laid materials, bonded carded web materials, hydroentangled materials, spunbond materials, and the like, and may include synthetic or natural fibers. It may be characterized by including.

In one particular embodiment, the shrinkable absorbent material in absorbent 24 includes thermoplastic elastomeric polymer fibers. Suitable materials for use in making the thermoplastic elastomeric fibers herein can be obtained as diblock, triblock or multiblock elastomeric copolymers, such as the KRATON elastomer resin from Shell Chemical Company. Olefin copolymers such as styrene-isoprene-styrene, styrene-butadiene-styrene, styrene-ethylene / butylene-styrene, or styrene-ethylene / propylene-styrene, which may be used under the trade name LYCRA polyurethane. children. Polyurethanes, including those sold by EI Du Pont de Nemours Co., (PEBAX) polyether block amides, including polyether block amides available from Ato Chemical Company under the trade name. Polyamide, HYTREL Polyester by trade name E. children. Polyesters such as those sold from Dupont Di Nemosa, and single site or metallocene catalyzed polyolefins available from Dow Chemical Co. under the AFFINITY tradename.

Many block copolymers can be used to make thermoplastic elastomeric fibers useful in the present invention. Such block copolymers are generally characterized as comprising an elastomer block middle portion and a thermoplastic end block portion. Block copolymers used in the present invention are generally three-dimensional physical crosslinked structures below the glass transition temperature (T ₂ ) of the terminal block portion. Block copolymers are also thermoplastics in that they can be melted, formed and reconstructed many times with little or no change in physical properties (assuming minimization of oxidative degradation).

One method of synthesizing such block copolymers is to polymerize the elastomeric intermediate block portion and the thermoplastic end block portion separately. After the intermediate block and terminal block portions are formed separately, they can be connected. Typically the middle block portion can be obtained by polymerizing diunsaturated and triunsaturated C ₄ -C ₁₀ hydrocarbons such as, for example, dienes such as butadiene, isoprene and the like and trienes such as 1,3,5-heptatriene and the like. When the end block portion A is joined to the intermediate block portion B, AB block copolymer units are formed, the units being coupled by various techniques or with various coupling agents such that the two AB blocks are joined together in a tail-to-tail ABCBA arrangement. It can provide structures such as ABA that are thought to be bound. Similar techniques can form radial block copolymers with a central or central multifunctional coupling agent of formula (AB) _n C, where n is a number greater than 2. When using the coupling agent technique, the functional value of C determines the AB index number.

Terminal block portion A is generally characterized as comprising poly (vinylarene), for example polystyrene, having an average molecular weight of 1,000 to 60,000. Intermediate block portion B is characterized by comprising substantially amorphous polyolefins or copolymers thereof, such as polyisoprene, ethylene / propylene polymers, ethylene / butylene polymers, polybutadienes, etc., which generally have an average molecular weight of about 5,000 to about 450,000 do. The total molecular weight of the block copolymer is suitably about 10,000 to about 500,000, more suitably about 200,000 to about 300,000. Any residual unsaturation in the middle block portion of the block copolymer can be selectively hydrogenated such that the content of olefinic double bonds in the block copolymer can be reduced to a residual ratio of less than 5%, suitably less than about 2%. Such hydrogenation tends to reduce susceptibility to oxidative degradation and can have a beneficial effect on elastomer properties.

Suitable block copolymers used in the present invention are characterized in that they comprise at least two polystyrene end block portions and substantially at least one ethylene / butylene intermediate block portion. As an example, ethylene / butylene can typically comprise most of the single unit in such block copolymers, for example at least 70% by weight of the block copolymer. The block copolymer can have three or more arms, and good results can be obtained when having 4, 5 or 6 arms. If desired, the middle block portion can be hydrogenated.

Linear block copolymers such as ABA, ABABA and the like are suitably selected based on the terminal block content, and large terminal blocks are preferred. For polystyrene-ethylene / butylene-polystyrene block copolymers, a styrene content of more than about 10% by weight, such as about 12 to about 30% by weight, is suitable. Polystyrene end block portions with higher styrene content generally have a relatively high molecular weight. A commercial example of such a linear block copolymer is a styrene-ethylene / butylene-styrene block copolymer having about 13% by weight of styrene units and the remainder of ethylene / butylene units, commercially available from Shell Chemicals under the trade name Kraton G1627 elastomer resin. to be. Typical properties of Kraton G1657 elastomer resins include 300% modulus of elasticity of 2 x 10 ⁶ kg / m 2 (3400 lb / in ² ), 1.4 x 10 ⁵ kg / m 2 (350 lb / in ² ), and 750% Elongation at break, Shore A hardness of 65, and Brookfield viscosity at room temperature and 25% by weight concentration in toluene solution are recorded at about 4200 centipoise and the like. Another suitable elastomer, Kraton G2740, is a styrene butadiene block copolymer blended with tackifiers and low density polyethylene.

Other suitable elastomeric polymers can also be used to make thermoplastic elastic fibers. These include elastomers (single site or metallocene catalyzed) polypropylene, polyethylene and other α-olefin homopolymers and copolymers, ethylene vinyl acetate copolymers, and substantially all of ethylene-propylene, butene-propylene and ethylene-propylene-butene And amorphous copolymers and terpolymers, but are not limited thereto.

Metallocene-catalyzed elastomeric polymers are relatively novel and are presently preferred in the present invention. The metallocene process for producing polyolefins uses metallocene catalysts activated (ie ionized) by cocatalysts.

Metallocene catalysts include bis (n-butylcyclopentadienyl) titanium dichloride, bis (n-butylcyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) scandium chloride, bis (indenyl) Zirconium dichloride, bis (methylcyclopentadienyl) titanium dichloride, bis (methylcyclopentadienyl) zirconium dichloride, cobaltocene, cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride, isopropyl (Cyclopentadienyl _1-1 -flowenyl) zirconium dichloride, molybdocene dichloride, nickellocene, niobose dichloride, lutenocene, titanocene dichloride, zirconocene chloride hydride, zircono Cen dichloride. A more specific list of such compounds is described in US Patent No. 5, assigned to Dow Chemical Company. 374,696 (Rosen et al.). Such compounds are also discussed in US Pat. No. 5,064,802 (Stevens et al.) Assigned to Dow.

Metallocene processes, in particular catalysts and catalyst support systems, are the subject of numerous patents. U.S. Pat. No. 4,542,199 (Kaminsky et al.) Discloses a formula (chloropentadienyl) ₂ MeRHal, wherein Me is a transition metal, Hal is halogen, and R is cyclopentadienyl or a C ₁ to C ₆ alkyl radical Or halogen, metallocene catalyst is described for the procedure of forming polyethylene.

U. S. Patent No. 5,189, 192 (LaPointe et al.) Assigned to Dow Chemical describes a process for preparing an addition polymerization catalyst via metal central oxidation. U.S. Patent 5,352,749 (Exxon Chemical Patents, Inc.) describes a process for polymerizing monomers in a fluidized bed. U.S. Patent 5,349,100 describes chiral metallocene compounds and their preparation by the generation of chiral centers by enantioselective hydride transitions.

Cocatalysts include the most common methylaluminoxanes (MAO), other alkylaluminum, and tris (pentafluorophenyl) boron, lithium tetrakis (pentafluorophenyl) boron and dimethylanilinium tetrakis (pentafluorophenyl) boron The same material as the boron-containing compound. Due to the problems of handling and product contamination, there is a continuing search for other cocatalyst systems or the feasibility of minimizing or even eliminating alkylaluminum. An important point is to activate or ionize the metallocene catalyst with cation formation for reaction with the monomer (s) to be polymerized.

Polymers prepared using metallocene catalysts have a narrow molecular weight distribution. "Narrow molecular weight distribution polymer" means a polymer having a molecular weight distribution of less than about 3.5. As is known in the art, the molecular weight distribution of a polymer is the ratio of the weight average molecular weight of the polymer to the number average molecular weight of the polymer. Methods for determining the molecular weight distribution are described in Encyclopedia of Polymer Science and Engineering, Volume 3, pages 299-300 (1985). Examples of narrow molecular weight distribution polyolefins include metallocene catalyzed polyolefins, single site catalyzed polyolefins, and bond-shaped catalyzed polyolefins as described above. As is known in the art, metallocene catalyzed polyolefins and bond-shaped catalyzed polyolefins are often referred to as a class of single site catalyzed polymers. Dispersions (M _w / M _n ) of less than 4 and even less than 2 are possible for metallocene prepared polymers. These polymers have a narrow short chain branch distribution when compared to other similar Ziegler-Natta prepared polymers.

The metallesene catalyst system can also be used to control the isotactic properties of polymers that are very similar to those with stereoselective metallocene catalysts. In fact, polymers with more than 99% isotacticity have been produced. It is also possible to produce high syndiotactic polypropylene using this system.

Controlling the isotacticity of the polymer also allows the preparation of polymers containing blocks of isotactic blocks and atactic materials that vary with respect to the length of the polymer chain. The structure makes the elastomeric polymer by the atactic portion. Synthesis of such polymers is described in Science, vol. 267 (January 13, 1995), page 191, KB Wagner's paper, which discusses the work of Coates and Waymouth, which is catalyzed by an atactic-oriented series. It is described that it varies between stereochemical forms resulting in polymer chains having consecutive lengths of isotactic stereocenters linked to lengths. The chain of isotactic reduces the production of elasticity. See Science, vol. 267, "Oscillating Stereocontrol: A Strategy for the Synthesis of Thermoplastic Elastomeric Polypropylene", p. 217, says Geoffrey W. Coates and Robert M. Waymouth, In the presence of metallocene bis (2-phenylindenyl) -zirconium dichloride is discussed their study of varying the polymer form between isotactic and atactic by changing the pressure and temperature in the reactor.

Industrial production of metallocene polymers is somewhat limited but growing. Such polymers are commercially available from Exxon Chemicals (Baytown, Texas, USA) under the trade name EXXPOL for polypropylene based polymers and EXACT for polyethylene based polymers. Dow Chemical (Midland, Mich.) Has a polymer available under the ENGAGE tradename. These materials are thought to have been prepared using non-stereoselective metallocene catalysts. Exxon generally refers to these metallocene catalyst techniques as "single site" catalysts, while Dowsa uses metallocene catalysts under the INSIGHT trade name to distinguish them from conventional Ziegler-Natta catalysts with multiple reaction sites. The technique is referred to as a "bound shape" catalyst. Other manufacturers such as Fina Oil, BASF, Amoko Hoist and Mobil are active in this field, and the marketability of polymers produced according to the technique will grow significantly in the next decade. will be.

Regarding metallocene based elastomeric polymers, U.S. Patent No. 5,204,429 (Kaminski et al.) Describes the preparation of elastomeric copolymers from cycloolefins and linear olefins using aluminoxanes and catalysts, which are stereorigid chiral metallocene transition metal compounds. It describes how you can do it. The polymerization is carried out in an inert solvent such as aliphatic or cycloaliphatic hydrocarbons such as toluene. The reaction can also be carried out in the gas phase using monomers to polymerize such as solvents. U.S. Pat.Nos. 5,278,272 (Lai et al.) And 5,272,236 (Lie et al.), Assigned to Dow Chemicals, entitled "Elastic Substantially Linear Olefin Polymers," describe polymers with special elasticity. have. Dow also manufactures elastomeric polyolefin family under the Engage trade name.

The elastomeric fibers may be substantially continuous or staple in length, but are preferably substantially continuous. Substantially continuous filaments exhibit better containment of cellulose fibers and superabsorbent materials than staple length fibers and provide a good distribution of liquid. Elastomeric fibers can be made using spunbonding methods, meltblowing methods or other suitable methods. The elastomeric fibers may have an average diameter of about 1 to 75 microns, preferably about 1 to 40 microns, more preferably about 1 to 30 microns.

The thermoplastic elastomeric fibers may be circular, but may also have other cross-sectional shapes such as oval, rectangular, triangular or polymorphic. The thermoplastic elastomeric fiber may be wettable. Thermoplastic elastomer fibers can be made wettable by first preparing thermoplastic elastomer fibers and then applying a hydrophilic surface treatment to the fibers.

Alternatively, thermoplastic elastomeric fibers can be made wettable by adding a hydrophilic component to the polymer prior to spinning. In general, the polymer can be polymerized with the thermoplastic elastomer component and the resulting copolymer material can be made hydrophilic to make it wettable, wherein the hydrophilic component is substantially any polymer used in the present invention that does not affect the elasticity of the fiber produced. It is suitable to Suitable hydrophilic components for use in the present invention include, but are not limited to, polyethylene oxide and polyvinyl alcohol, as well as various commercially available hydrophilic surfactants.

In another embodiment, the thermoplastic elastomeric fibers may be bicomponent or bicomponent filaments, one of the polymer components being hydrophilic or made hydrophilic. An exemplary embodiment is a sheath / core bicomponent filament with a hydrophilic core surrounded by a hydrophilic sheath. Other additives such as pigments may also be included in the elastomeric filaments.

When the absorbent body 24 is a blend of elastomeric polymer fibers, superabsorbent fibers and any other fibers, such as cellulose fibers, an appropriate percentage of elastomeric polymer fibers and superabsorbent fibers in the absorbent body 24 may be employed. It can vary in various ranges depending on the desired properties. For example, the absorbent 24 may be from about 3 to about 95 weight percent, preferably from about 5 to about 65 weight percent, more preferably from about 5 to about 50 weight percent, based on the dry weight of the absorbent 24. It may be characterized in that it comprises an elastomeric polymer fiber. Combinations of such elastomeric polymer fibers with superabsorbent fibers can be made by any method known to those skilled in the art.

In embodiments where elastomeric polymer fibers are dispersed throughout absorbent 24, absorbent 24 may be formed by a coform method for more uniform distribution of elastomeric polymer fibers in absorbent 24. Such coform materials are generally described in U.S. Patent No. 4,100,324, issued July 11, 1978 (Anderson et al.), And U.S. Patent No. 4,604,313, issued August 5, 1986 (McFarland et al.). , And US Pat. No. 5,350,624, issued September 27, 1994, which is incorporated herein by reference. Typically, such coform layers are characterized by comprising a gas-forming matrix of elastomeric polymer fibers and other fibers, such as cellulose or superabsorbent fibers. The coform absorber is formed by first forming at least one first air stream containing elastomeric polymer fibers and combining the first air stream with at least one second air stream of another fiber. The first and second air streams combine under intense conditions to form an integrated air stream in which the different fibers are completely uniformly distributed. The integrated airflow forms a layer of material towards the forming surface. One or more of these coform layers can then be formed continuously to provide a continuous web of coform absorbent material. This method can also be used to provide individual segments or portions that can be mixed and formed with conventional absorbent cores.

In one particular embodiment, the absorbent body 24 or at least a portion of the absorbent articles of the present invention comprises coform absorbent and superabsorbent fibers of elastomeric polymer fibers, wherein the elastomer to superabsorbent fiber weight ratio is from about 3/97 to about 95/5. to be. For example, the absorbent 24 or at least a portion thereof is about 80% by weight superabsorbent fiber available from Technical Absorbents under the OASIS 101 trade name and an elastomer commercially available from Shell Chemical under the Kraton G2740 trade name. About 20% by weight of polymeric fibers. These coform absorbent composites exhibit up to 50% shrinkage in both the machine direction and the machine cross direction when exposed to about 60% relative humidity, resulting in a 75% reduction in surface area.

It is believed that shrinkage of the material is caused because the shape of the fiber absorbent material changes. Initially, these absorbers are long cylindrical (fiber) shapes, and when exposed to water vapor these fiber materials shrink into a spherical shape that constricts the system. It should be noted that the matrix material (referred to above as an elastic resin) provides resistance to shrinkage, so that the degree of shrinkage can be altered by appropriate selection of the material. Elastomers are particularly suitable for shrinkage because they have less resistance to these forces. Shrinkage of the system can be varied by selecting the composition of the web as well as the raw material (matrix material and fiber absorber) and raw material properties.

In another embodiment, the contraction of the absorber 24 is caused by moisture rather than water vapor. A method for obtaining a moisture sensitive shrinkable absorbent material is using a water sensitive polymer matrix. The material will include the polymer matrix described above and superabsorbent materials such as superabsorbent particulates or fibers. A wide range of moisture sensitive polymers can be used. Suitable polymers will vary in molecular shape from the extended chain to the coil at the desired moisture content. The results can optionally be further strengthened and used in the formation of shrinking materials by suitable process techniques and also by degree of crystallinity to orient the polymer chain in the desired direction. In addition to processing aids to enhance the moisture sensitive behavior of the polymer, other additives may also be used to achieve the optimal combination of moisture sensitive behavior and mechanical properties.

A wide range of polymers exhibit this moisture sensitive behavior and are well known to those skilled in the art. One example of a polymer suitable for this purpose is polyacrylic acid and its copolymers of various degrees of neutralization. Other moisture sensitive polymers that would be useful include synthetic and natural polymers and modified natural polymers. Examples of these are polymers and copolymers of polyvinyl alcohol, polyacrylonitrile and copolymers of various degrees of hydrolysis, polymethacrylic acid, hydrophilic polyurethanes and polyethylene oxides. Natural polymers and modified natural polymers that can be used include hydroxypropyl cellulose, carboxymethyl cellulose, guar gum and modified guar gum, modified starch based polymers and chitosan and modified chitosan. Blends of these polymers may also be used. Such polymers may be incorporated into the absorbers 24 of various features of the present invention in a variety of suitable ways as described above for shrinking absorbent materials that shrink upon exposure to water vapor.

In one particular embodiment, absorber 24 may include both water vapor and moisture sensitive materials as discussed for improved performance.

Such shrinkable absorbents 24 can also provide improved customization retention upon wetting by reducing or eliminating sagging and slowing of the absorbents 24 exhibited by conventional absorbent cores.

In order to provide improved breathability when wet, the material forming the absorbent 24 may be configured to have a high rate of swelling in the z direction or thickness of the absorbent 24 to provide a more open porous structure when wet. . An example of such a material is US Patent Application (Attorney Docket No.) under the name ["WET-FORMED COMPOSITE DEFINING LATENT VOIDS AND MACRO-CAVITIES") filed with the present specification in the name of Edens et al. 15,126, the wet forming composites, which are incorporated herein by reference. Wet formed composites are generally contained by interbonded fibers that define internal pupils or macro-cavities between the fibers. As used herein, the terms "wet forming", "wet-laid", and the like refer to composites formed from the process by which fibers are dispersed in a liquid dispersion medium to form a slurry. The slurry is deposited on the forming surface to form a composite by removing at least a portion of the dispersion medium. Such methods are known to those skilled in the art.

In its dry state, the wet formed composite is a pore structure suitable for quickly absorbing fluid. When fluid is inserted into the wet forming composite, some of the wet, swollen and expanded composite, particularly the superabsorbent material, expands its internal pupil and macro-cavity. This expansion increases the internal pupil volume and consequently results in breathability of the composite. Part of the structure that is not wetted, i.e., the fluid front and the fluid front, remains in an unexpanded form, thus making it possible to absorb liquid at a relatively high rate. Thus, the dry portion of the wet formed composite serves to direct the fluid to the portion of the wet formed composite that is increasingly away from the initial point of the insulator.

Suitable fibers and superabsorbent materials for wet forming composites are generally those suitable for absorbent body 24 as described above. Superabsorbent materials present in the wet forming composites are swellable in the dispersion medium. As used herein, an absorbent material is at least 20 times, in particular at least 50, more particularly at least 75, particularly 100 times its weight in the dispersion medium when the absorbent material is dispersed in an excess of the dispersion medium for a period of one hour. Above, it can absorb especially 150 times or more.

Various materials may be suitable for use as the dispersion medium. Examples of suitable dispersion media are water, other aqueous materials and the like. For reasons such as availability and economic reasons, water is the preferred dispersion medium. The fibers are suitably present in the dispersion medium in an amount of about 0.005 to about 3.0% by weight, in particular about 0.01 to about 2.0% by weight, especially about 0.01 to about 1.0% by weight, based on the total weight of the fibers and the dispersion medium. The dispersion medium may contain other additives known to those skilled in the paper industry. Other suitable additives include, but are not limited to, binders, viscosity modifiers, adhesives, wet strength additives, pH control additives, flocculants, and the like, provided they do not adversely affect the formation or performance characteristics of the wet formed composite.

The dry wet formed composite is more than about 90% dry weight, in particular greater than about 95% dry weight, in particular greater than about 98% dry weight but less than 100% dry weight based on the total weight of fibers and absorbent materials present in the wet formed composite. It characterized in that it comprises a fiber. The superabsorbent material is less than about 10% dry weight, in particular less than about 5% dry weight, in particular less than about 2% dry weight or 0% dry weight based on the total weight of fibers and superabsorbent materials present in the wet formed composite. Present in excess. Superabsorbent materials have macro-cavities so that the wet formed composites contain the absorbed fluid and improve breathability, but should be chosen so that the product capacity is not significantly reduced by the amount of water that must be removed from the swollen superabsorbent material during drying. .

The wet forming composite combines the fibers, the dispersion medium of the fibers, and the superabsorbent material that swell in the dispersion medium, and gives sufficient contact time between the superabsorbent material and the dispersion medium so that the superabsorbent material before the superabsorbent material forms the wet formed composite. Swelling, forming a wet forming composite, and drying the wet composite such that the superabsorbent material shrinks in a significant amount, thereby forming a macro-cavity in the wet forming composite. Wet forming composites can also be densified such that the macro-cavities collapse, thereby forming latent or macro-cavities in the wet forming composite.

Before drying the wet formed composite, the superabsorbent material absorbs at least about 20 times, in particular at least about 50 times, more particularly at least about 75 times, in particular at least about 100 times, more particularly at least about 150 times its weight in the dispersion medium. It is desirable to combine the superabsorbent material with the slurry of fibers. Suitably, the superabsorbent material is swollen in the amount described above before the wet formed composite is formed. The superabsorbent material may be added to the slurry of fibers so that the superabsorbent material is dispersed relatively uniformly throughout the slurry prior to forming the wet formed composite.

The basis weight of the dry wet formed composite is about 600 g / m 2 or less, especially about 250 g / m 2 or less, more particularly about 150 g / m 2 or less, especially about 150 to 250 g / m 2, suitably less than about 100 g / m 2. Or 40 g / m 2. Basis weight is chosen such that the composite provides acceptable performance at a given raw material cost.

When densifying dry wet formed composites, the composites have a density of at least about 0.1 g / cc, in particular at least about 0.12 g / cc, more particularly at least about 0.15 g / cc, in particular from about 0.12 to about 0.15 g / cc, but about 0.3 less than g / cc. The density is selected such that the internal pore structure of the dry wet formed composite is suitable for wicking and dispersing fluid throughout the composite. The density is also chosen such that the dry wet formed composite imparts softness and thinness to the product into which the wet formed composite is incorporated.

For example, the construction of an absorbent body 24 using a material such as a shrinkable absorbent material or a wet formed composite may result in an absorbent article having a greater ventilation rate when wet. For example, such a shape may provide an absorbent article that defines a wetness / dryness ventilation ratio of about 0.50 or greater, generally about 0.70 or greater, preferably about 0.80 or greater, and more preferably about 0.90 or greater for improved performance. Can provide. Preferably, the composition of the absorbent and absorbent articles of the various properties of the present invention has an absorbent article that defines a ventilation ratio on wet / ventilation ratio on drying for at least about 1.00, generally at least about 1.05, preferably at least about 1.10 for improved performance. To provide.

In addition, the absorbent body 24 of various aspects of the present invention has a large number of high air permeability to allow air and vapor to easily pass through the absorbent 24 and the vapor permeable backsheet 20 into the atmosphere outside of the diaper 10. Include the band. For example, as representatively illustrated in FIGS. 1 and 2, the absorber 24 has a plurality of air passages 40 that provide the absorber 24 with a zone or zone 42 having high air permeability. It may include. In the illustrated embodiment, portions of absorber 24 adjacent air passage 40 provide a high absorption zone or region 44. The high air permeability zone 42 allows for maximum ventilation from the absorber 24, while the high absorption zone 44 is intended to receive and retain most body secretions. Absorber 24 can define any number of high air permeability zones 42 that provide improved ventilation. Preferably, for improved performance the absorber 24 defines a zone 42 with at least three, more preferably at least five different air permeability.

As representatively illustrated in FIGS. 1 and 2, the highly air permeable zone 42, such as the air passage 40, enhances the air permeability of the absorbent article to provide urine and urine on the garment-side surface of the backsheet 20. The same vapor is configured to reduce hydration of the wearer's skin during use without excessive condensation. Condensation of this vapor on the outer surface of the diaper 10 can undesirably dampen the wearer's clothing. Zone 42 having high air permeability is generally an area of the diaper where air and vapor can be transferred out of the vapor permeable backsheet 20 through the absorber 24 and other intermediate material layer (s) from the topsheet 22. Located in For example, the high air permeability zone 42 may be located throughout the entire absorbent 24, or of such absorbent 24 providing maximum ventilation, such as the middle section 16 of the diaper 20. May be optionally located in the region. In certain embodiments, for improved ventilation, the high air permeability zone 42 is located in each of the front region 12 and the middle region 16 of the diaper 10.

On the other hand, the high absorption zone 44 is not intended to deliver high levels of air and steam from inside the diaper. Accordingly, ventilation from the topsheet 22 of the diaper 10 to the backsheet 20 of the diaper and to the atmosphere (outside of the diaper) generally occurs in the zone 42 where the air permeability through the absorber 24 is high. In addition, some ventilation through the absorber 24 may occur to a limited extent in the high absorption zone 44.

Zones with high air permeability may have any desired shape, including rectangular, circular, hourglass, oval, etc., and may include selected longitudinal or transverse strips or multiple regions that may be intermittently located. Can be. For example, in FIGS. 1 and 2, the zone 42 having high air permeability is provided by a plurality of air passages 40 or holes through the absorber 24, which are generally circular. In this form, the superabsorption zone 44 is characterized by including the non-perforated portion of the absorber 24 between the air passages 40.

Zone 42 having high air permeability may be any that effectively provides improved ventilation while preventing vapor from absorber 24 from excessively condensing through and on the garment-side surface of backsheet 20. It may have a desired dimension. Preferably, the high air permeability zone 42 is about 5% to about 75%, more preferably at least about 10%, even more preferably about 10% to the total surface area of the absorbent body 24 of the diaper 10. A total area of about 70%, even more preferably about 10 to about 60% can be defined. For example, in diapers for use with infants of medium physique, the high air permeability zone 42 may define a total area of about 6 to about 90 cm 2.

If the total area of the zone 42 having high air permeability is larger than the area, the diaper 10 may occur to an extent that steam condensation on the exposed garment side surface of the backsheet 20 is undesirable. This results in undesirable effects of giving a sticky feel to the outer surface of the diaper. On the other hand, if the total area of the zone 42 with high air permeability is smaller than the area, the diaper 10 may have a low level of ventilation, which leads to a high level of skin hydration, which has undesirable consequences of skin irritation and rash. Can bring

As representatively illustrated in FIGS. 1 and 2, the high air permeability zone 42 of the absorbent body 24 of the diaper 10 is at least substantially permeable to air and preferably permeable to water vapor. It is configured to be. For example, the high air permeability zone 42 of the absorber 24 is at least about 10%, more preferably at least about 20%, much more than the Fraser porosity of the high absorption zone 44 of the absorber 24. Preferably at least about 50% of large fragrance porosity is defined. As used herein, the term "fracture porosity" refers to a value determined according to the Fraser porosity test described below. If the Frazier porosity of the high air permeability band is less than the value described above, the diaper 10 may exhibit low ventilation levels, which may result in high skin hydration levels, which may result in undesirable effects of skin irritation and rashes. have.

Zones with high air permeability can be provided in various ways. Zone 42 having high air permeability may be an integral part of absorber 24 of the absorbent article, or may be provided by a hole, hole or open space in absorber 24. For example, portions of absorber 24 may be discontinuous or removed to provide zone 42. Alternatively, the high air permeability zone 42 may be provided by portions of the absorber 24 configured to absorb less fluid secretion thereby providing improved air flow during use. For example, portions of absorber 24 may contain substantially less or no superabsorbent material than other portions of absorber 24 to provide this improved air flow. Alternatively, portions of the absorber 24 may be treated or coated with a solution that makes them hydrophobic to provide a zone 42 with high air permeability to the selected area. In another form, the zone 42 having high air permeability forms a cavity or hole in the absorber 24, and the absorber 24, such as the material described below as suitable for the surge treatment layer 34 in the hole or cavity, By placing another material having a higher air permeability than).

Examples of some forms of absorber 24 according to various aspects of the invention are exemplarily illustrated in FIGS. For example, in FIGS. 1 and 2, the high air permeability zone 42 of the absorber 24 is provided by a plurality of air passages 40 or holes passing through the absorber 24. In the illustrated embodiment, the air passage 40 is intermittently located along the entire length and width of the absorber 24. The illustrated air passage 40 is circular and defines a diameter of about 1.27 cm and a total opening area of about 12% of the total surface area of the absorber 24.

In FIGS. 3 and 4, the absorbent body 24 is in the form of separate segments 46 spaced along the longitudinal direction 36 of the diaper 10. In this form, the zone 42 with high air permeability is provided by the space between the separate segments 46 of the absorber 24. The absorber 24 can have any number of segments 46 of various shapes and sizes. For example, in the illustrated embodiment, the absorbent body 24 includes four different segments 46 spaced apart in the longitudinal direction 36 of the diaper 10. The illustrated segments 46 are generally rectangular in shape and in the illustrated embodiment define a width that is less than the width of the absorber 24 defined by the width of the surge treatment layer 34 and the venting layer 32. Alternatively, segment 46 may define a width substantially equal to the width of absorber 24. To help keep the segments 46 spaced apart, the segments 46 may be contained between a wrapsheet (not shown) or between two sheets of material, the surge treatment layer 34 and the vent layer 32. In the illustrated embodiment, the segment 46 comprises a laminate of superabsorbent material between two sheets of material or layers, and the high air permeable zone 42 provided by the space between the segments 46 comprises an absorber ( Define an opening area of about 40% of the total surface area of 24).

In FIGS. 5 and 6, the zone 42 of high air permeability of the absorber 24 is characterized by a plurality of air passages 40 or through the absorber 24 similarly to the embodiments illustrated in FIGS. 1 and 2. Provided by a hole. However, in the embodiment illustrated in FIGS. 5 and 6, the air passage 40 is not located in the rear waist region 14 of the diaper 10 in the absorbent 24 but in the front waist region 12 and the middle region. It is located at (16). In addition, in the embodiment illustrated in FIGS. 5 and 6, the absorber 24 comprises an upper layer 48 and a lower layer 50, the upper layer 48 extending along only a portion of the length of the absorber 24. . In this form, most of the absorbent 24 may be located in the front waist region 12 and the middle region 16 of the diaper 10 for improved absorption and reduced cost. The illustrated air passage 40 is circular and defines a diameter of about 1.27 cm and a total opening area of about 12% of the total surface area of the absorber 24.

Since the thickness of the absorbent 24 and the superabsorbent material in the absorbent 24 is thin, the liquid intake rate of the absorbent 24 itself may be too low, or adequately bears against the liquid that is excreted multiple times into the absorbent 24. Can't do it. In order to improve overall liquid intake and ventilation, the diapers of various features of the present invention may further include a porous liquid permeable surge treatment material layer 34 as illustrated in FIGS. 1 and 2. The surge treatment layer 34 is typically less hydrophilic than the absorber 24 and has an adjustable level of density and basis weight to quickly collect and temporarily retain liquid surges and transport the liquid from its initial entry point to transport the liquid. Discharge substantially completely to another portion of the absorber 24. This form can help prevent liquid from accumulating and collecting on the absorbent garment portion located on the wearer's skin, thus reducing the wearer's feeling of dampness. In addition, the structure of the surge treatment layer 34 generally improves ventilation in the diaper 10.

Various woven and nonwoven fabrics can be used to make the surge treatment layer 34. For example, surge treatment layer 34 may be a layer of meltblown or spunbonded webs of synthetic fibers, such as polyolefin fibers. In addition, the surge treatment layer 34 may be a bonded-carded web or an airlaid web made of natural and synthetic fibers. The bonded-carded web can be a thermally bonded web, for example bonded using low melt binder fibers, powders or adhesives. The web may optionally comprise a mixture of several fibers. The surge treatment layer 34 may be made of a substantially hydrophobic material, and the hydrophobic material may be optionally treated with a surfactant or otherwise processed to impart the desired level of wettability and hydrophilicity. In certain embodiments, surge treatment layer 34 comprises a hydrophobic nonwoven material having a basis weight of about 30 to about 120 g / m 2.

For example, in certain embodiments, surge treatment layer 34 may be comprised of bonded-carded web nonwovens that define a total basis weight of about 83 g / m 2 and include bicomponent fibers. This type of surge treatment layer 34 comprises about 60 weight percent polyethylene / polyester (PE / PET) sheath-core bicomponent fibers having a fiber denier of about 3 d and a fiber denier of about 6 d. And a homogeneous blend of about 40% by weight of one component polyester fiber having a fiber length of about 3.8 to about 5.08 cm.

In the illustrated embodiment, the surge treatment layer 34 is arranged in direct contact with the absorber 24 to allow liquid communication. The surge treatment layer 34 may be adjustablely connected to the topsheet 22 using a conventional adhesive pattern, such as a spiral adhesive pattern. In addition, the surge treatment layer 34 can be adjustablely connected to the absorber 24 using conventional adhesive patterns. The amount of adhesive added should be sufficient to provide the desired level of bonding, but should be small enough so as not to overly limit the flow of liquid from the topsheet 22 through the surge treatment layer 34 to the absorber 24.

The absorber 24 is placed in liquid communication with the surge treatment layer 34 to receive the liquid discharged from the surge treatment layer and hold and store the liquid. In the illustrated embodiment, the surge treatment layer 34 consists of a separate layer located on another separate layer of the absorber 24, thereby forming a double layer arrangement. Surge treatment layer 34 quickly collects and temporarily retains the released liquid, transports this liquid from its initial point of contact, diffuses the liquid into other portions of surge treatment layer 34, and then absorbs this liquid into the absorber. Serves to discharge substantially completely into the layers or layers that make up the device.

The surge treatment layer 34 may be of any desired shape. Suitable shapes include, for example, round, rectangular, triangular, trapezoidal, oval, dog bowl, hourglass or oval. In some embodiments, for example, the surge treatment layer may be generally rectangular in shape. In the illustrated embodiment, the surge treatment layer 34 has the same dimensions as the absorber 24. Alternatively, surge treatment layer 34 may span only a portion of absorber 24. When the surge treatment layer 34 only partially extends along the length of the absorber 24, the surge treatment layer 34 may be selectively positioned anywhere along the absorber 24. For example, surge treatment layer 34 may function more effectively when it is biased toward the front waist region 12 of the garment. The surge treatment layer 34 may also be nearly centered around the longitudinal centerline of the absorber 24.

Suitable additional materials for the surge treatment layer 34 are seed. U. S. Patent No. 5,486, 166, issued January 23, 1996; titled invention: “FIBROUS NONWOVEN WEB SURGE LAYER FOR PERSONAL CARE ABSORBENT ARTICLES AND THE LIKE”, US Patents of Ellis et al. No. 5,490,846, issued Feb. 13, 1996; Title of Invention: “IMPROVED SURGE MANAGEMENT FIBROUS NONWOVEN WEB FOR PERSONAL CARE ABSORBENT ARTICLE AND THE LIKE”, US 5,364,382 to Latimer et al. (1994) The title of the invention: “ABSORBENT STRUCTURE HAVING IMPROVED FLUID SURGE MANAGEMENT AND PRODUCT INCORPORATING SAME”, the contents of which are incorporated herein by reference.

As representatively illustrated in FIGS. 1 and 2, the diaper 10 may also include a ventilation layer 32 positioned between the backsheet 20 and the absorber 24. The breathing layer 32 encourages air to move inside and through the diaper 10, and serves to prevent the backsheet 20 from interfacial contact with at least a portion of the absorber 24. In particular, the ventilation layer 32 functions as a circuit in which air and water vapor can move from the absorber 24 through the vapor permeable backsheet 20.

The ventilation layer 32 is suitable for surge treatment layers 34 such as nonwoven fabrics (eg, spunbond, meltblown or carded), woven or knitted fibrous webs made of natural fibers and / or synthetic polymer fibers. It can be formed from materials. For example, suitable fibers include acrylic fibers, polyolefin fibers, polyester fibers or blends thereof. In addition, the ventilation layer 32 may be formed from porous foam materials such as open bubble polyolefin foam, reticulated polyurethane foam, and the like. Vent layer 32 may comprise a single material layer or a composite of two or more material layers. In certain embodiments, the ventilation layer 32 comprises a hydrophobic nonwoven material having a thickness determined at a suppression pressure of 0.34 kPa (0.05 psi) and greater than about 0.10 cm and a basis weight of about 20 to about 120 g / m 2. For example, the ventilation layer 32 may be comprised of bonded-carded web nonwovens that define a total basis weight of about 83 g / m 2 and include bicomponent fibers. In this form, the ventilation layer 32 has about 60% by weight polyethylene / polyester (PE / PET) sheath-core bicomponent fibers having a fiber denier of about 3 d and a fiber denier of about 6 d and about 3.8 to about It may be a homogeneous blend of about 40% by weight one-component polyester fibers having a fiber length of 5.08 cm.

The ventilation layer 32 may be of any desired shape. Suitable shapes include, for example, round, rectangular, triangular, trapezoidal, oval, dog-bow shaped, hourglass or oval. The ventilation layer 32 can extend beyond the absorber 24 and be exactly the same as the absorber or to a portion of the absorber. For example, the breathing layer 32 may be appropriately positioned above the middle region 16 of the diaper 10 and may be substantially centered from each side with respect to the longitudinal centerline 36 of the diaper 10. Can be. In general, it is preferable that the entire absorbent body 24 be superimposed on the ventilating layer 32 to prevent substantially all inter-surface contact between the backsheet 20 and the absorbent body 20. In the illustrated embodiment, the ventilation layer 32 has the same dimensions as the absorber 24. This minimizes the dampness on the garment side surface of the backsheet 20 while maximizing ventilation.

In the illustrated embodiment, the vent layer 32 is arranged in direct contact with the absorber 24 to allow liquid communication. The vent layer 32 may be adjustablely connected to the backsheet 20 using a conventional adhesive pattern, such as a spiral adhesive pattern. In addition, the ventilation layer 32 can be adjustablely connected to the absorber 24 using conventional adhesive patterns. The amount of adhesive added should be sufficient to provide the desired level of bonding, but low enough to not overly limit the movement of air and vapor from the absorbent 24 through the backsheet 20.

In addition, the venting layer 32 quickly collects and temporarily retains the released liquid, allowing the liquid to pass through the absorber 24 and in particular through the high permeability zone 42 in the absorber 24. Can function. Aeration layer 32 then transports this liquid from the initial point of contact and diffuses the liquid to other portions of the aeration layer 32, which then discharges the liquid substantially completely into the layer or layers that make up the absorber 24. You can.

As representatively illustrated in FIGS. 1-6, several embodiments of the present invention advantageously provide an improved absorbent article that substantially reduces the wearer's skin hydration level during use as compared to conventional absorbent articles. Reduced skin hydration levels make skin dry and more comfortable and allow the skin to allow less microbial growth. Thus, the wearer of an absorbent article made in accordance with the present invention has a reduced level of skin hydration, which can result in reduced occurrence of skin irritation and rashes.

Test procedure

Hydrostatic test

A hydrostatic test is a measure of the liquid barrier properties of a substance. In general, a hydrostatic test determines the height (cm) of water at the column held by the material before a predetermined amount of water passes through it. Materials with high hydrohead values indicate a greater barrier to liquid penetration than materials with low hydrohead values. The hydrostatic test is performed according to Method 5514-Federal Test Methods Standard No. 191A.

Fraser Porosity Test

Fraser porosity values used herein are determined using the Frazier Air Permeability Tester (manufactured by Frazier Precision Instrument Co., Gatorsburg, Maryland) and Method 5450-Federal Test Method Standard No. 191 A. You can decide. For the purposes of the present invention, this test is performed with a sample of 8 inches by 8 inches.

Water vapor transmission test

Suitable techniques for determining the WVTR (water vapor transfer rate) of a substance are: For the purposes of the present invention, a round sample of 3 inches (76 mm) in diameter was tested for test and control material Celguard 2500 (Celguard). 2500) (Chest Celanese Corporation). Prepare two or three samples for each material. The test cups used for testing are cast from aluminum, flanged, 2 inches deep, and attached to a mechanical seal and neoprene gasket. Cups are obtained from the Twin-Albert Instrument Company (Philadelphia, PA) under the trade name Vaporometer cup # 681. Pour 100 ml of distilled water into each bailometer cup and place individual samples of the test and control materials across the opened top of each individual cup. Tighten the screw-on flange to form a seal along the edge of the cup and allow the relevant test material or control material to be exposed to the ambient atmosphere over a circular area of 62 mm diameter (open and exposed area about 30 cm 2). The cups are then weighed, placed on a tray, and placed in a forced air oven set to 38 ° C. (100 ° F.). The oven is a constant temperature oven that circulates outside air therethrough to prevent water vapor from accumulating inside. Suitable forced air ovens are, for example, Blue M Power-O-Matic 60 ovens (from Blue M Electric Co., Blue Island, Illinois). After 24 hours, remove the cup from the oven and weigh it. The preliminary test WVTR is calculated as follows:

The relative humidity in the oven is not particularly controlled. Under the predetermined set conditions of 38 ° C. (100 ° F.) and ambient relative humidity, the WVTR of Celgard 2500 was determined to be 5000 g / m 2 / 24h. Thus, Celgard 2500 is used as a control sample for each test. Celgard 2500 is a 0.0025 cm thick film made of microporous polypropylene.

Skin hydration level

Skin hydration levels are determined by measuring total evaporation moisture loss (EWL) and can be determined using the following test procedure.

The test is performed on partially trained infants who did not apply lotion or ointment to the skin and did not bathe 2 hours before the test. Each infant tests one diaper during each test period. The test diaper includes a test cord and a control cord. Test diaper (test cord and control cord) randomly

Each test diaper is weighed before and after use to ascertain the volume of liquid added into the diaper. The felt-tip pen is marked with an "X" in the target zone inside the diaper, where "X" is 6.5 inches below the upper front edge of the diaper and centered from each side. EWL measurements are performed with an evaporator, for example an Evaporimeter EP1 instrument (obtained from Servomed AB, Stockholm, Sweden). Each test measurement is made for 2 minutes and the EWL value is measured once per second (total 120 EWL values). The figures output from the eBay Limiter EP1 instrument provide the evaporation moisture loss (EWL) rate in g / m 2 / h. Skin hydration (SHV) is expressed in units of total moisture loss per unit area measured over a two minute sampling period and is calculated as follows:

Preliminary skin hydration measurements are taken after a 15-minute “full dry” period, with the infant lying flat wearing only an elongated T-shirt or dress. The measurement is performed on the infant's lower abdomen (area corresponding to the target zone of the diaper) using an evaporator for the purpose of establishing the initial skin hydration of the infant's skin in the target zone of the diaper. If the preliminary SHV is less than 10 g / m 2 / h, the diaper is worn by the infant. If the preliminary SHV is greater than 10 g / m 2 / h, the “completely dry” period is extended until less than 10 g / m 2 / h is recorded. Before securing the diaper to the infant, the tube is placed so that the liquid flow hits the previously indicated target zone. Once the diaper is secured, 210 ml of adjusted 0.9% by weight aqueous saline is added in three portions, 70 ml each time at a rate of 15 ml / sec, with a 45 second delay between each.

The infant wears the diaper for 60 minutes, after which the diaper is removed, and the degree of skin hydration is measured for the lower abdomen corresponding to the target band indication of the diaper. The measurement is performed over 2 minutes. Next, the diaper used is weighed. Relative humidity and temperature measurements can be performed in diapers prior to skin hydration measurements. The next day, the test procedure is then repeated for each infant using the type of diaper (test or control) the infant has not yet worn. Control diapers provide standardized criteria for comparing the performance of diaper types that are tested and evaluated. Control diapers used in the tests performed in connection with the examples are available from HUGGIES from Kimberly-Clark Corporation. ) Supreme diaper.

For all infants, the data used for the saline solution loading should be discarded. The reported value for the mean net SHV (g / m 2 / h) is the post-wear skin hydration measured in the lower abdomen (target band indication) for all infants before the diaper is worn by the infant (after the “completely dry” period). ) Is the arithmetic mean of the subtracted skin hydration values measured in the lower abdomen. Separate mean net SHVs are determined for test cord diapers and control cord diapers.

Net skin hydration is determined as follows:

Net SHV _i = Y-Z

Where Y = skin hydration measured on each infant's target band display

Z = after the "fully dry" period before the infant wears the diaper

Reference skin hydration measured in the lower abdomen

SHV _i = degree of skin hydration in each infant

next,

Average net SHV =

Where N = number of infants studied

The percent reduction in skin hydration is calculated as follows:

% Reduction =

Where C = net SHV _i of the control diaper cord

D = net SHV _i of the test diaper cord

N = number of infants studied

Tracker gas test

The tracer gas test is a measure of the ventilation rate of garments, such as absorbent articles, and is generally the steady / steady state test described in TAPPI JOURNAL., Volume 80, No. 9, September 1997. In general, the ventilation rate value is calculated from the measured mass exchange in the garment. This test involves injecting a tracer gas at a constant rate inside the absorbent by the outer surface of the body of the mannequin with the absorbent held around the mannequin. At the same time, the concentration of tracer gas in the space between the absorbent article and the mannequin is measured by withdrawing the sample at the same rate as the scan. The ventilation rate is then determined based on the mass balance of tracer gas and air in the space in question. The tracer gas test is completed as follows:

equipment

1. Mannequins-This test is performed with infant Step 3 or Step 4 size diapers weighing about 16 to about 28 pounds and about 22 to about 37 pounds, respectively. Diapers are worn on mannequins with the following dimensions:

Step 3

Height (from waist to knee) 26 cm

Waist circumference 42 cm

Hip circumference 44 cm

Thigh circumference 22 cm

Step 4

Height (from waist to knee) 28 cm

Waist circumference 48 cm

Hip circumference 51 cm

Thigh circumference 27 cm

2. Test Area-Environmentally controlled to 20 ° C and 50% relative humidity.

3. CO ₂ Analyzer—Infrared CO ₂ analyzer, such as Model 17515A (available from Vacu-Med Vacumetrics, Ventura McGrace Street, # 102 4483, CA).

4. Rotameters Rotameters that maintain gas flow rates, such as the Mathson Rotameter Model TS-35 (available from Specialty Gases Southeast Inc., 3496, Peachtree Parkway, Suwanee, GA, USA).

5. Gas Cylinders-Two gas cylinders of calibrated medical gas at 4 kPa pressure (available from Specialty Gases Southeast Inc., 3496, Suwanee Peachtree Parkway, Georgia, USA). The tracer gas contains 5% CO ₂ and air, and the calibration gas is 100% air.

step

1. Turn on the CO ₂ analyzer. After the analyzer has been turned on for 30 minutes, calibrate the analyzer with a calibration gas and adjust the flow control so that the flow rate through the analyzer is 150 cc / min.

2. Put on the mannequin the diaper to be tested.

3. Turn on the CO ₂ tracer gas flow. The flow rate of tracer gas injected into the space between the diaper and the mannequin should be equal to the sample flow rate (150 cc / min) through the CO ₂ analyzer.

4. Measure and record the concentration (C) of tracer gas (CO ₂ ) in the space between the diaper and the mannequin every 10 seconds for 20 minutes. The data for the last 10 minutes are averaged and used to calculate the ventilation rate as follows:

Ventilation Rate = 150 cc / min * [(C _T -C) / (C-C _o )]

Where C _T = concentration of tracer gas (5%)

C = concentration of tracer gas in the measured space

C _o = concentration of tracer gas in the chamber environment (0.04%)

The ventilation rate on drying is the ventilation rate determined according to the above procedure before excretion in the diaper. Ventilation rate on wet is the ventilation rate determined according to the procedure except for the following: After fixing the diaper to the mannequin, adjusted 180 ml (step 3) or 210 ml (step 4) of 0.9 weight% aqueous saline solution adjusted in three times Add 60 ml or 70 ml each time at a rate of 15 ml / sec, with a 45 second delay between each round. The ventilation rate on wet / ventilation rate on drying is determined by dividing the ventilation rate on wet by the ventilation rate on drying for the same sample.

Candida albicans growth test

Candida albicans growth test measures the effect of absorbent garments, such as disposable diapers, on the viability of pathogenic microorganisms, particularly Candida albicans. In general, the Candida albicans viability test is inoculated with a known Candida albicans cell suspension to the area indicated by the line between the forearms in the palm of the test subject and covered with the full thickness patch from the absorbent garment, 24 Determining viability after time.

A full thickness test sample patch of about 5 cm in length and about 5 cm in width is cut from the target zone of each product to be tested. In general, the target zone is the portion of the product for receiving urine released from the wearer and typically includes the middle and anterior waist region portions of the product slightly ahead of the transverse centerline of the product. In a representative diaper form, the full thickness test sample patch includes a topsheet, absorber, backsheet and all intermediate layers. About 15 ml of 0.9 wt% saline solution is added to the test sample patch and allowed to absorb for 2 minutes before the sample is placed on the forearm of the subject. A test site area of about 6.15 cm 2 is marked from the palm of each test subject to the forearm. About 0.01 ml of a 0.9 wt% saline solution containing known Candida albicans cell suspension is delivered to the test site by micropipette, and then the suspension is applied evenly across the test site. After air drying, the test site is covered with a test sample patch and the entire circumference of the sample is held in place with adhesive tape.

After 24 hours, the test sample patch was removed and the detergent scrub method described in “New Method for Quantitative Investigation of Skin Bacteria”, P. Williamson and AM Klingman, Journal of Investigative Dermatology, 45: 498-503, 1965. A quantitative culture is obtained from the test site using the detergent scrub method (the contents of this document are incorporated herein by reference). In short, a sterile glass cylinder surrounding an area of 6.15 cm 2 is centered over the test site and secured to the skin. 1 ml of 0.1 wt% Triton-x-100 in 0.075 M phosphate buffer, pH 7.9, is pipetted into a glass cylinder and the area is scrubbed for 1 minute using a sterile Teflon rod. The fluid is sucked into a sterile pipette and again 1 ml of 0.1 wt% Triton-x-100 in 0.075 M phosphate buffer at pH 7.9 is added to the glass cylinder. Repeat the scrub step and collect 2 washes. Each pooled sample is diluted 10-fold stepwise with 0.05 wt% Triton-x-100 in 0.0375 M phosphate buffer at pH 7.9. 0.01 ml aliquots of each dilution are inoculated onto Sabourand agar containing antibiotics. Two-fold cultures are prepared and incubated for 48 hours at room temperature.

After incubation, the number of colony forming units is calculated using standard microbiological methods. The candida albicans viability under the test sample patch is then conventional absorbent with a non-breathable outer cover (ie, an outer cover with a WVTR of less than 100 g / m 2 / 24h), such as the diaper described in connection with Comparative Example 4 below. It can be compared with Candida albicans growth under a control patch from the arm.

Skin temperature test

Skin temperature values can be determined by using the following test procedure. This test is performed on the bare forearm of an adult who does not have skin disease without applying lotion, powder or ointment to the skin. In addition, the test subjects did not bathe, do not swim, smoke, do not exercise, and do not consume caffeine 2 hours before and during the test. Each test subject tests two absorbent articles, such as diapers, during the test period. The test diaper may comprise a control cord such as a test cord and a cord identified in Comparative Example 6. Test diapers (test cords and control cords) are randomly picked and are conventional step 3 size diapers, i.e. diapers for infants weighing 16 to 28 pounds.

Each test diaper is weighed before and after use to check the volume of liquid added into the diaper. Mark a 1 "x 1" square on the inside and outside of the diaper at the target zone using a pen, the center of the square being 6.0 inches below the upper front edge of the diaper and centered from each side Located in Temperature and humidity measurements are available from Digi-Sense under the tradename Model # 91090-00. Temperature / Humidity Logger; Thermoelectron pair probe (Vernon Hills, Illinois, USA) with a vinyl-insulated 10-kt gold plated disk sensor, commercially available under the trade name P-08506-80 attached to Vernon Hills, Illinois, USA. (Available from Cole-Parmer of the raw material). The hot electron pair probes are calibrated with precalibrated probes 3370-52 assembled in a data autometer. Skin temperature is measured continuously once per minute.

Upon arrival, each subject has an environmental acclimation period of 15 minutes in a controlled environment of 40% relative humidity and 21.7 ° C. (71 ° F.). One temperature sensor is attached to each forearm approximately midway between the wrist and elbow. Place the head of the sensor facing the elbow and place a piece of tape on top of the sensor, such as Steri-Strip sealing tape (commercially available from 3M) (0.635 cm x 3.81 cm (0.25 "x 1.5")). Hold the sensor in place and secure the sensor head in place with another piece of tape. Record reference skin temperature for 5 minutes (5 minutes total test time) without diaper attached to the forearm.

A sample diaper is then attached to each forearm of each test subject, with a 2.54 cm x 2.54 cm (1 "X 1") target band on the diaper positioned over the temperature sensor. Before securing the diaper to the forearm of the test subject, a fluid dispenser nozzle, adapted to room temperature, is placed over the temperature sensor in each diaper so that the fluid flow hits the previously indicated target zone. Each diaper does not overlap the target zone and is held in place by filling masking tape that fills the top and bottom of the diaper together without contacting the wearer's skin. A size 3 elastic Maryas retainer (available from Glenwood, Inc.) is placed on the entire diaper and forearm. After fixing the diaper, the dry diaper skin temperature is recorded for 5 minutes.

Subsequently, 180 ml of 0.9 wt% aqueous saline adjusted to body temperature is added to the diaper at a rate of 15 ml / sec each time in 60 ml portions over three times, with a 45 second delay period between each time. Remove the fluid dispenser nozzle from each diaper. The skin temperature is recorded every minute while the subjects wear each diaper for an additional 120 minutes. Next, the diaper is removed and weighed.

The value reported in the skin temperature test is the arithmetic mean of the values of all test subjects at each time point during that test period for each sample. The skin temperature on wet is then divided by the skin temperature value 120 minutes after wearing the wet sample (130 minutes total test time) by the skin temperature value 5 minutes after the dry sample (10 minutes total test time). Determine the skin temperature ratio when drying.

The following examples are provided to further understand the present invention. Certain materials and variables are exemplary and are not intended to limit the scope of the invention in any way.

Example 1

Disposable diapers having the same general structure as Huggies Supreme Step 3 diapers described in connection with Comparative Example 2 below were made and tested by hand. Each diaper was substantially the same as a Supreme Diaper except that the diaper's backsheet, absorbent core, surge layer, and resilient leg bands were replaced or modified and a vent layer was added between the backsheet and the absorbent core.

In the diapers tested, the backsheet included a microporous film / nonwoven laminate material comprised of a spunbond nonwoven material laminated to the microporous film. The spunbond nonwoven material consisted of about 1.8 denier filaments extruded from a copolymer of ethylene and about 3.5 wt% propylene and defined a basis weight of about 20 g / m 2. The film consisted of a template coextruded film with calcium carbonate particles and defined a basis weight before stretching of about 58 g / m 2. The film was preheated, stretched and annealed to form micropores, which were then laminated to the spunbond nonwoven material. The microporous film / nonwoven laminate based material obtained had a basis weight of 45 g / m 2 and a water vapor transmission rate of about 4000 g / m 2 / 24h. Examples of such film / nonwoven laminate materials are described in more detail in US Patent Application No. 08 / 882,712, filed June 25, 1997; McCoymack et al., Entitled: “Low Gauge Film and Film / Nonwoven Laminate” The contents of this document are incorporated herein by reference.

The absorbent core of the diaper tested was a bilayer absorbent having the general form shown in FIGS. 5 and 6 except that no layer of absorbent had holes or holes. The absorbent core comprises an upper layer and a lower layer, the upper layer extending from the front edge of the absorbent core to a point approximately two thirds of the total length of the absorbent core. The absorbent core comprised about 10 to about 11 g of wood pulp fibers and about 10 to about 11 g of superabsorbent material, and thus included about 50% by weight of wood pulp fibers and about 50% by weight of superabsorbent material. The lower layer has a basis weight of about 230 g / m 2 and the upper layer has a basis weight of about 560 g / m 2, giving a total basis weight of about 790 g / m 2 in the front region of the core and about in the rear region of the core. A basis weight of 230 g / m 2 was provided. The absorbent core also defined a width in the crotch region of about 6.35 cm.

The surge layer was the same material as the surge layer of the Supreme Diaper described in Comparative Example 2 except that it was located between the absorbent core and the topsheet and modified to have the same dimensions as the absorbent core. The diaper also included a ventilation layer between the absorbent core of the diaper and the back sheet. The vent layer was made of the same material as the surge layer and had the same dimensions as the absorbent core. The diaper also included an elasticized leg band assembly along about two thirds of the length of each longitudinal side edge of the diaper. The assembly had six elastic material strands laminated to a breathable nonwoven layer. Elastic strands are arranged along the longitudinal length of the diaper to lycra to elasticize and gather the leg bands of the diaper. ) Made of coalesce.

Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 2

A disposable diaper having the same general structure as the diaper described in connection with Example 1 was tested by hand. This diaper was substantially the same as the diaper of Example 1 except that the absorbent was modified to include a plurality of holes in the region where the upper layer overlaps the lower layer as illustrated in FIGS. 5 and 6. The hole had a diameter of 1.27 cm and provided an opening area of about 12% based on the total surface area of the absorbent body. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 3

A disposable diaper having the same general structure as the diaper described in connection with Example 2 was tested by hand. This diaper was substantially the same as the diaper of Example 2 except that the ventilation layer between the absorber and the backsheet was removed. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 4

A disposable diaper having the same general structure as the diaper described in connection with Example 2 was tested by hand. This diaper was substantially the same as the diaper of Example 2 except that the absorbent hole had a diameter of 2.54 cm and also defined an opening area of about 12% of the total surface area of the absorbent body. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 5

A disposable diaper having the same general structure as the diaper described in connection with Example 2 was tested by hand. The diaper comprises about 62% by weight of wood pulp fibers and about 38% by weight of superabsorbent, and has a basis weight in the front zone of about 750 to about 850 g / m 2 and about 375 to about 425 g / m 2 It was substantially the same as the diaper of Example 2, except that it was replaced with a non-layered absorbent defining a basis weight in the rear region of. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 6

A disposable diaper having the same general structure as the diaper described in connection with Example 2 was tested by hand. The diaper replaced the bilayer absorbent core with a laminate comprising about 80% by weight of superabsorbent material sold from Stockhausen under the trade name Faber SXM 880 wrapped in a tissue layer of cellulose fibers having a basis weight of about 26 g / m 2. It was substantially the same as the diaper of Example 2 except for that. The absorber also included a hole having a diameter of 1.27 cm and providing an opening area of about 12% of the total surface area of the absorber. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 7

A disposable diaper having the same general structure as the diaper described in connection with Example 2 was tested by hand. The diaper was replaced with a laminate containing about 80% by weight of superabsorbent material commercially available from Stockhausen under the trade name Faber SXM 880 wrapped in a tissue layer of cellulose fibers having a basis weight of about 26 g / m 2. Was substantially the same as the diaper of Example 2. The laminate was provided in four segments as representatively illustrated in FIGS. 3 and 4, which resulted in an absorbent opening area of about 40% of the total surface area of the absorbent. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Example 8

A disposable diaper having the same general structure as the diaper described in connection with Example 2 was tested by hand. This diaper was substantially the same as the diaper of Example 2 except that the backsheet was modified to define a water vapor transfer rate of about 1870 g / m 2 / 24h. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Comparative Example 1

Disposable diapers having the same general structure as Supreme Step 3 diapers described in connection with Example 2 were tested by hand. This diaper was substantially the same as the diaper of Example 2 except that the backsheet was replaced with a 15.4 mil thick polyethylene film having a water vapor transfer rate of less than 100 g / m 2 / h. Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Comparative Example 2

Disposable diapers having the same general structure as diapers sold from Kimberly Clark Corporation under the trade name Huggies Supreme Step 3 were tested.

Essentially, the Supreme Diaper consisted of an absorbent core consisting of a mixture of wood pulp fibers and superabsorbent material surrounded by two pieces of cellulose wrap sheet having a basis weight of about 16 to 21 g / m 2. The absorbent core included about 12.5 to about 13.5 g of airlaid wood pulp and about 7.0 to about 8.5 g of superabsorbent material. Superabsorbent materials were purchased from Stockhausen under the trade name Faber SXM 880. The superabsorbent material was homogeneously mixed with the pulp fibers to form a monolayer having a density of 0.25 to 0.35 g / cm 3. The homogeneous mixture of superabsorbent material and wood pulp fibers is zoned and distributed along the longitudinal direction to provide a basis weight of about 600 to about 700 g / m2 in the front region of the absorbent core and a basis weight of about 300 to 350 in the rear region of the absorbent core. g / m 2 was provided.

Supreme diapers also included a composite backsheet consisting of a vapor permeable barrier layer adhesively laminated to a spunbond / meltblown / spunbond laminate material (hereinafter referred to as “SMS”). The SMS material had a basis weight of about 27 g / m 2. The vapor permeable barrier layer consisted of a polyolefin film having a thickness of about 17.78 μm (0.7 mil) and a basis weight of about 19.5 g / m 2. Polyolefin film materials were marketed under the trade name EXXAIRE from Exxon Chemical Patents Incorporated. The vapor permeable barrier layer adhered to the SMS laminate and placed between the SMS laminate material of the backsheet and the absorbent core. The backsheet had a water vapor transfer rate of about 1500 g / m 2 / 24h. The absorbent core was sandwiched between the topsheet and the backsheet, which consisted of a spunbond web of polypropylene fiber having a basis weight of about 17 g / m 2. A surge treatment layer consisting of a bonded carded web was placed between the topsheet and the absorbent core. The surge layer comprises bicomponent fibers and defined an overall basis weight of about 83 g / m 2. The surge layer is one having a polyethylene / polyester (PE / PET) sheath-core bicomponent fiber having a fiber denier of about 3 d and a fiber length of about 6 d and a fiber length of about 3.8 to about 5.08 cm. The component was a homogeneous blend of about 40% by weight of polyester fibers. The surge layer also defined a width of about 10.2 cm and a length of about 16.5 cm. The front edge of the surge layer was located at a distance of 5.1 cm from the front edge of the absorbent core.

Supreme diapers also included a one-component elasticized waistband and waist flap assembly at each longitudinal end of the diaper. The assembly had multiple strands of elastomeric material sandwiched between the polymeric film layer and the nonwoven layer. The polymer film was a 0.00075 inch thick film consisting of a blend of low density linear polyethylene and ultra low density polyethylene. The nonwoven layer consisted of a 20 g / m 2 polypropylene spunbond web. The elastic strands consisted of about 8 to 16 lycra elastic strands arranged along the transverse direction of the diaper to elasticize and gather the diaper waistband and inner waist flap. Supreme diapers also included a longitudinal containment flap that extends the entire length of the diaper to elasticize the leg bands along each longitudinal side edge of the diaper. The elastic strands of the leg bands and containment flaps consisted of lycra elastomers arranged along the longitudinal length of the diaper to elasticize and gather the diaper leg bands and containment flaps.

Four diaper samples were tested according to the tracer gas test. The results are shown in Table 1 below.

Average drying ventilation rate (cm3 / min) Average wetting ventilation rate (cm 3 / min) Ventilation rate when wet / Ventilation rate ratio when drying Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 822794679105075872467749551513 224310220360190240153316110171 0.270.390.320.340.250.330.230.632.160.33

The test results obtained from Examples 1 to 8 and Comparative Examples 1 and 2 indicate that compared to conventional diapers, diapers made in accordance with the present invention generally have improved ventilation levels both in drying and in wetting.

Example 9

Four diaper samples having the same general structure as the diapers described in connection with Example 2 were made by hand and tested according to the skin hydration test. These diapers were substantially the same as the diapers of Example 2 except that they had a size similar to that of commercially available step 4 size diapers, and the absorbent body was a single layer with the same thickness as a whole, and the diameter of the holes was 2.54 cm. Diapers defined an average skin hydration of 8.1 g / m 2 / h. In addition, the results are shown in Table 2 below.

Example 10

Four diaper samples having the same general structure as the diapers described in connection with Example 6 were made by hand and tested according to the skin hydration test. These diapers had substantially the same size as commercially available Step 4 diapers, substantially the same as the diapers of Example 6 except that the absorbent body defined a basis weight of about 560 g / m 2 and the diameter of the holes was 2.54 cm. . Diapers defined an average skin hydration of 2.8 g / m 2 / h. In addition, the results are shown in Table 2 below.

Example 11

Four diaper samples having the same general structure as the diapers described in connection with Example 7 were made by hand and tested according to the skin hydration test. These diapers were substantially the same as the diapers of Example 7, except that they had a size similar to that of commercially available step 4 size diapers. Diapers defined an average skin hydration of 1.6 g / m 2 / h. In addition, the results are shown in Table 2 below.

Comparative Example 3

Disposable diapers having the same general structure as diapers sold from Kimberly Clark Corporation under the trade name Huggies Supreme Step 4 were tested. In essence, the step 4 sized diaper was similar to the step 3 sized diaper described in connection with Comparative Example 2 above except that the material was larger in size.

Four diaper samples were tested according to the above skin hydration test. Diapers defined an average skin hydration of 19.3 g / m 2 / h. In addition, the results are shown in Table 2 below.

Skin Hydration (g / ㎡ / h) Example 9 Example 10 Example 11 Comparative Example 3 8.12.81.619.3

The test results obtained from Examples 9-11 and Comparative Example 3 indicate that diapers made according to the present invention exhibit significantly improved skin hydration compared to conventional diapers. In particular, diapers made in accordance with the present invention exhibited a 58 to 92% reduction in skin hydration. A slight decrease in skin hydration was expected due to the increased ventilation of the diaper, but this decrease in size was an unexpected result.

Example 12

Diaper samples having the same general structure as the diapers described in connection with Comparative Example 2 were made by hand and tested. These diapers were substantially the same as the diapers of Comparative Example 2 except that the backsheet was modified to define a water vapor transfer rate of about 3000 g / m 2 / 24h. Diapers were tested according to the Candida albicans viability test. Samples of Example 12 and Comparative Example 4 (control) were tested from the palm of each of the seven subjects to the forearm. About 0.01 ml of a 0.9 wt% saline solution containing a suspension of 5.71 log of Candida albicans colony forming units was transferred to the test site by micropipette, and then the suspension was applied evenly across the test site. Diaper samples according to this example defined an average Candida albicans growth of 1.96 log of Candida albicans colony forming units. Thus, the diaper according to this example defined a 26% reduction in Candida albicans growth compared to the average Candida albicans growth in the control group (Comparative Example 4).

Example 13

A diaper sample was made with the same general structure as the diaper described in connection with Example 2 except that the backsheet defined a water vapor transfer rate of about 5000 g / m 2 / 24h. These diapers were tested according to the Candida albicans viability test. Samples of Example 13 and Comparative Example 4 (control) were tested in the stomach from the palm of each of the seven subjects to the forearm. About 0.01 ml of a 0.9 wt% saline solution containing a suspension of 5.71 log of Candida albicans colony forming units was transferred to the test site by micropipette, and then the suspension was applied evenly across the test site. Diaper samples according to this example are expected to define an average Candida albicans viability of Candida albicans colony forming units of less than 1.75 log and less than 1.50 log. Thus, compared to the average Candida albicans viability of the control (Comparative Example 4), it is expected that diapers according to this example will probably define a reduction of Candida albicans viability of about 34% and about 43%.

Comparative Example 4

Diaper samples having the same general structure as the diapers described in connection with Comparative Example 2 were made by hand and tested. These diapers were substantially the same as the diapers of Comparative Example 2 except that the backsheet was replaced with a 25.4 μm (1.0 mil) thick polyethylene film material having a water vapor transfer rate of less than 100 g / m 2 / 24h. Diapers were tested from the palm to the forearm of each of the seven subjects according to the Candida albicans viability test. About 0.01 ml of a 0.9 wt% saline solution containing a suspension of 5.71 log of Candida albicans colony forming units was transferred to the test site by micropipette, and then the suspension was applied evenly across the test site. Sample diapers according to this example defined an average Candida albicans growth of 2.65 log of Candida albicans colony forming units.

Example 14

Diaper samples having the same general structure as the diapers described in connection with Example 13 were machine tested. In particular, the backsheet of the diaper defined a water vapor transfer rate of about 5000 g / m 2 / 24h. Diapers were tested according to the Candida albicans viability test. Samples of Example 14 and Comparative Example 5 (control) were tested from the palms to the forearms of each of the 20 test subjects. About 0.01 ml of a 0.9 wt% saline solution containing a suspension of 4.92 log of Candida albicans colony forming units was transferred to the test site by micropipette, and then the suspension was applied evenly across the test site. Diaper samples according to this example defined an average Candida albicans growth of 1.26 log of Candida albicans colony forming units. Thus, the diaper according to this example defined a 61% reduction in Candida albicans growth compared to the average Candida albicans growth in the control group (Comparative Example 5).

Comparative Example 5

Diaper samples having the same general structure as the diapers described in connection with Comparative Example 4 were machine tested. In particular, the backsheet of the diaper included 25.4 μm (1.0 mil) thick polyethylene film material with a water vapor transfer rate of less than 100 g / m 2 / 24h. Diapers were tested from the palms to the forearms of each of the 20 subjects according to the Candida albicans viability test. About 0.01 ml of a 0.9 wt% saline solution containing a suspension of 4.92 log of Candida albicans colony forming units was transferred to the test site by micropipette, and then the suspension was applied evenly across the test site. Diaper samples according to this example defined an average Candida albicans growth of 3.26 log of Candida albicans colony forming units.

The test results of Examples 12 and 14 and the expected test results of Example 13 show that the diapers made according to the invention reduce microbial viability and microbial infection when compared with conventional absorbent diapers and the test results of Comparative Examples 4 and 5 It can be seen that the occurrence is reduced. This reduced microbial growth is achieved by reducing the closure of the skin by increasing the breathability of the diaper upon drying and when wet.

Example 15

A diaper sample was prepared having the same general structure as the diaper described in connection with Example 2 except that the backsheet defined a water vapor transfer rate of about 5000 g / m 2 / 24h. Diapers were tested according to the skin temperature test. Samples were tested on one forearm of each of 11 test subjects. The test results are shown in FIG. Diaper samples according to this example defined a skin temperature on wet / skin temperature on dry ratio of 0.970.

Comparative Example 6

Diaper samples with the same general structure as the diapers described in connection with Comparative Example 2 were prepared. The diapers were substantially the same as the diapers of Comparative Example 2 except the backsheet was replaced with a 25.4 μm (1.0 mil) thick polyethylene film material having a water vapor transfer rate of less than 100 g / m 2 / 24h. Diapers were tested according to the skin temperature test. Samples were tested on one forearm of each of 11 test subjects. The test results are shown in FIG. Diaper samples according to this example defined a skin temperature on wet / skin temperature on dry ratio of 1.014.

As shown in FIG. 7, the test results obtained from Example 15 maintain a more constant and reduced skin temperature when wet as compared to the test results obtained from conventional absorbent diapers and Comparative Example 6 in which diapers made in accordance with the present invention. It can be done. It is assumed that a more constant and reduced skin temperature is achieved by reducing the closure of the skin by increasing the breathability of the diaper when wet. In addition, as shown in FIG. 7, diapers made in accordance with the present invention can maintain a skin temperature at wet that is substantially the same as the skin temperature when the wearer did not wear the diaper. By maintaining the skin temperature in this way it is possible to improve the comfort of the wearer.

Since the present invention has been described in some detail above, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit of the invention. All such changes and modifications are considered to be within the scope of the invention as defined by the appended claims.

Claims (80)

Absorbent, anterior lumbar region, posterior lumbar region, and anterior lumbar region and posterior lumbar region, defined by a tracer gas test (described in the Detailed Description of the Invention herein) defined as at least about 190 cc / min. A disposable absorbent article comprising an intermediate section connecting the sections. The absorbent article of claim 1 wherein said wetness ventilation rate calculated according to said tracer gas test is at least about 200 cc / min. The absorbent article of claim 1 wherein the wetness ventilation rate calculated according to the tracer gas test is at least about 225 cc / min. The absorbent article of claim 1 wherein said wetness ventilation rate calculated according to said tracer gas test is at least about 250 cc / min. The absorbent article of claim 1, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 525 cc / min. 3. The absorbent article of Claim 2, wherein the drying ventilation rate calculated according to the tracer gas test is defined as at least about 575 cc / min. The absorbent article of claim 1 wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. The absorbent article of claim 1 wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. The absorbent article of claim 1 wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 12 g / m 2 / h. Absorbent, front, defined by a tracer gas test (described in the detailed description of the invention herein) defined as a dry ventilation rate of at least about 525 cc / min and a wet ventilation rate / drying ventilation ratio of at least about 0.20. A disposable absorbent article comprising a waist region, a back waist region, and an intermediate region connecting the front waist region and the back waist region. The absorbent article of claim 10, wherein the wetness ventilation rate calculated according to the tracer gas test is defined as about 190 cc / min or more. The absorbent article of claim 10, wherein the wetness ventilation rate calculated according to the tracer gas test is defined as at least about 225 cc / min. The absorbent article of claim 10, wherein said dry ventilation rate calculated according to said tracer gas test is at least about 575 cc / min. The absorbent article of claim 10, wherein said dry ventilation rate calculated according to said tracer gas test is at least about 625 cc / min. The absorbent article of claim 10 wherein the wetness / dryness ventilation rate ratio calculated according to the tracer gas test is at least about 0.23. The absorbent article of claim 10, wherein said dry ventilation rate calculated according to said tracer gas test is at least about 625 cc / min, and said wet ventilation rate / dry ventilation rate is at least about 0.23. The absorbent article of claim 10, wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. The absorbent article of claim 10, wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. The absorbent article of claim 16 wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. a) a vapor permeable backsheet, defined by a water vapor transfer rate test (described in the detailed description of the invention herein), defined as at least about 1000 g / m 2 / 24h, b) a liquid permeable top sheet positioned facing the back sheet in front; c) an absorber located between the backsheet and the topsheet A disposable absorbent article comprising: a ventilation rate upon wetting calculated according to a tracer gas test (described in the Detailed Description of the Invention herein) defined as at least about 190 cc / min. 21. The absorbent article as in claim 20, wherein said vapor permeable backsheet is substantially liquid impermeable. 21. The absorbent article of claim 20, wherein the vapor permeable backsheet is configured to provide a hydrohead value of at least about 60 cm calculated according to a hydrostatic fluid test (described in the Detailed Description of the Invention herein). . 21. The absorbent article of claim 20 wherein the vapor permeable backsheet is configured to provide a hydrohead value of at least about 80 cm calculated according to a hydrostatic fluid test (described in the Detailed Description of the Invention herein). 21. The absorbent article of claim 20 wherein the vapor permeability backsheet of said vapor permeable backsheet, calculated according to said water vapor transfer rate test, is at least about 1500 g / m2 / 24h. 21. The absorbent article of claim 20, wherein said wet ventilation rate calculated according to said tracer gas test is at least about 225 cc / min. 21. The absorbent article of claim 20, wherein said wet ventilation rate calculated according to said tracer gas test is at least about 250 cc / min. 21. The absorbent article of Claim 20, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 525 cc / min. 21. The absorbent article of claim 20, wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. The absorbent article of Claim 20, wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. The absorbent article of claim 20, wherein the skin hydration degree calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 12 g / m 2 / h. 21. The absorbent article of claim 20, wherein the wet ventilation rate / dry ventilation rate ratio calculated according to the tracer gas test is defined as at least about 0.20. An absorbent body, anterior waist region, posterior waist region, and anterior waist region, wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. A disposable absorbent article comprising an intermediate section connecting the back waist region. 33. The absorbent article of claim 32, wherein said skin hydration rate calculated according to said skin hydration test is less than about 15 g / m 2 / h. 33. The absorbent article of Claim 32, wherein said skin hydration rate calculated according to said skin hydration test is less than about 12 g / m 2 / h. 33. The absorbent article of claim 32, wherein said skin hydration rate calculated according to said skin hydration test is less than about 10 g / m 2 / h. 33. The method of claim 32, wherein the dry ventilation rate calculated according to the tracer gas test (described in the detailed description of the invention herein) is defined as at least about 525 cc / min, and the wet ventilation rate is at least about 190 cc / min. Absorbent defined. Absorbent, anterior waist region, posterior waist region, and the waist region and the posterior region defined by a tracer gas test (described in the detailed description of the invention herein), defined as a wetness ventilation rate / dry ventilation rate ratio of about 0.50 or more. A disposable absorbent article comprising an intermediate section connecting the lumbar region. 38. The absorbent article of Claim 37, wherein said wetness / dryness ventilation rate ratio calculated according to said tracer gas test is at least about 0.70. 38. The absorbent article of Claim 37, wherein said wet ventilation rate / dry ventilation rate ratio calculated according to said tracer gas test is at least about 0.80. 38. The absorbent article of claim 37, wherein the wetness to dryness / dryness to dryness ratio calculated according to the tracer gas test is at least about 0.90. 38. The absorbent article of claim 37, wherein said wet ventilation rate / dry ventilation rate ratio calculated according to said tracer gas test is at least about 1.00. 38. The absorbent article of Claim 37, wherein the wetness ventilation rate calculated according to the tracer gas test is defined as at least about 190 cc / min. 38. The absorbent article of Claim 37, wherein the wetness ventilation rate calculated according to the tracer gas test is defined as at least about 200 cc / min. 38. The absorbent article of Claim 37, wherein the wetness ventilation rate calculated according to the tracer gas test is defined as at least about 225 cc / min. 38. The absorbent article of claim 37, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 200 cc / min. 40. The absorbent article of Claim 39, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 200 cc / min. 38. The absorbent article of Claim 37, wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. 38. The absorbent article of Claim 37, wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. 38. The absorbent article of Claim 37, wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 12 g / m 2 / h. 38. The absorbent article of Claim 37, wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 10 g / m 2 / h. The method of claim 37, a) a vapor permeable backsheet, defined by a water vapor transfer rate test (described in the detailed description of the invention herein), defined as at least about 1000 g / m 2 / 24h, b) a liquid permeable top sheet positioned facing the back sheet in front; c) an absorbent article comprising an absorbent body positioned between the backsheet and the topsheet. 52. The absorbent article as in claim 51, wherein said vapor permeability backsheet, calculated according to said moisture vapor transmission rate test, is at least about 1500 g / m2 / 24h. 53. The absorbent article as in claim 51, further comprising a ventilation layer positioned between said backsheet and said absorbent body. 54. The absorbent article of Claim 53, wherein the vent layer comprises a hydrophobic nonwoven material having a thickness of at least about 0.10 cm and a basis weight of about 20 to about 120 g / m 2. 54. The absorbent article of Claim 53, further comprising a surge treatment layer positioned between the topsheet and the absorbent material, wherein the surge treatment layer comprises a nonwoven material having a basis weight of about 30 to about 120 g / m 2. . a) a vapor permeable backsheet, defined by a water vapor transfer rate test (described in the detailed description of the invention herein), defined as at least about 1000 g / m 2 / 24h, b) a liquid permeable top sheet positioned facing the back sheet in front; c) an absorber located between the backsheet and the topsheet A disposable absorbent article comprising a, defined as a tracer gas test (described in the Detailed Description of the Invention herein), wherein the rate of wet ventilation / dry ventilation ratio is defined as about 1.00 or greater. 59. The absorbent article of claim 56, wherein said wet ventilation rate / dry ventilation rate ratio calculated according to said tracer gas test is at least about 1.05. 59. The absorbent article of claim 56, wherein said wet ventilation rate / dry ventilation rate ratio calculated according to said tracer gas test is at least about 1.10. 57. The absorbent article of Claim 56, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 200 cc / min. 59. The absorbent article of Claim 56, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 225 cc / min. 57. The absorbent article of Claim 56, wherein the dry ventilation rate calculated according to the tracer gas test is defined as at least about 250 cc / min. The absorbent article of claim 56 wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. The absorbent article of claim 56 wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. The absorbent article of claim 56 wherein the skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 12 g / m 2 / h. 59. The absorbent article of claim 56, wherein said vapor transmission rate of said vapor permeable backsheet, calculated according to said water vapor transmission rate test, is at least about 1500 g / m 2 / 24h. A front waist region, a back waist region, and an intermediate region connecting the front waist region and the back waist region, a) a vapor permeable backsheet, defined by a water vapor transfer rate test (described in the detailed description of the invention herein), defined as at least about 1000 g / m 2 / 24h, b) a liquid permeable top sheet positioned facing the back sheet in front; c) an absorber located between the backsheet and the topsheet And at least a portion of the absorbent shrinks at least about 5% in at least one of the machine direction and the machine cross direction when exposed to at least one of water vapor and water. 67. The absorbent article of claim 66, wherein said absorbent body comprises a plurality of segments, and said shrinkage of said absorbent member provides a zone of high air permeability between said segments. 67. The absorbent article of claim 67 wherein said segment is longitudinally apart from said absorbent article. 68. The absorbent article of claim 67, wherein said high air permeability zone is defined as a total surface area of at least about 10% of the total surface area of said absorbent body. 68. The absorbent article of claim 67, wherein said high air permeability zone is located in said intermediate region and said front waist region of said absorbent article, but not in said rear waist region. 67. The absorbent article of claim 66, wherein a portion of the absorbent body shrinks at least about 10% in at least one of the machine direction and the machine cross direction. 67. The absorbent article of claim 66, wherein said absorbent comprises elastomeric fibers. 67. The absorbent article of Claim 66, wherein the wet ventilation rate / dry ventilation rate ratio calculated according to the tracer gas test (described in the detailed description of the invention herein) is defined as at least about 0.50. 67. The absorbent article of Claim 66, wherein the wetness ventilation rate / dryness ventilation rate ratio calculated according to the tracer gas test (described in the detailed description of the invention herein) is defined as at least about 0.70. 67. The absorbent article of Claim 66, wherein the degree of skin hydration calculated according to the skin hydration test (described in the detailed description of the invention herein) is defined as less than about 18 g / m 2 / h. 67. The absorbent article of Claim 66, wherein the degree of skin hydration calculated according to the Skin Hydration Test (described in the detailed description of the invention herein) is defined as less than about 15 g / m 2 / h. 67. The absorbent article of claim 66, wherein said vapor transmission rate of said vapor permeable backsheet, calculated according to said water vapor delivery rate test, is at least about 1500 g / m2 / 24h. 67. The absorbent article of claim 66, further comprising a ventilation layer positioned between the backsheet and the absorbent body. 79. The absorbent article of Claim 78, wherein the vent layer comprises a hydrophobic nonwoven material having a thickness of at least about 0.10 cm and a basis weight of about 20 to about 120 g / m 2. 79. The absorbent article of Claim 78, further comprising a surge treatment layer positioned between the topsheet and the absorbent material, wherein the surge treatment layer comprises a nonwoven material having a basis weight of about 30 to about 120 g / m2. .