Absorbent article having improved breathability

An absorbent article includes a vapor permeable backsheet, a liquid permeable topsheet positioned in facing relation with the backsheet; and an absorbent body located between the backsheet and the topsheet which defines multiple zones of high air permeability. The absorbent article may also include a ventilation layer between the absorbent body and the backsheet and a surge management layer between the absorbent body and the topsheet. The article exhibits improved air exchange within the article during use. As a result, the article exhibits substantially reduced levels of hydration of the wearer's skin when in use which renders the skin less susceptible to the growth of microorganisms.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an absorbent article for absorbing body 
fluids and exudates, such as urine. More particularly, the present 
invention relates to absorbent garments, such as disposable diapers and 
adult incontinence garments, which are configured to absorb body exudates 
while also helping to provide reduced skin hydration. 
2. Description of the Related Art 
Many known diaper configurations employ absorbent materials located between 
a liquid pervious topsheet and a vapor and liquid impermeable backsheet. 
Such backsheets are well suited to prevent the migration of liquid waste 
from the absorbent materials to the outer garments of a wearer. 
Unfortunately, the use of liquid and vapor impermeable backsheets can 
result in a high degree of humidity within the diaper when in use which 
may result in relatively high skin hydration levels. The occlusive, moist 
environment inside diapers incorporating such backsheets can promote the 
growth of microorganisms, including Candida albicans, which can 
undesirably lead to the onset of diaper dermatitis (diaper rash). 
Diaper dermatitis can afflict almost every infant at some time during the 
diaper wearing years. The most severe form of this condition is usually 
caused by secondary infection with the fungi Candida albicans. Although 
other factors influence the pathogenesis of this fungi, one critical 
factor is the relative humidity within the diaper which is directly 
related to the occlusion or semi-occlusion of the diaper area. 
In order to reduce the humidity level within diapers, breathable polymer 
films have been employed as outer covers for absorbent garments, such as 
disposable diapers. The breathable films are typically constructed with 
micropores to provide desired levels of liquid impermeability and air 
permeability. Other disposable diaper designs have been arranged to 
provide breathable regions in the form of breathable panels or perforated 
regions in otherwise vapor-impermeable backsheets to help ventilate the 
garment. 
Conventional absorbent articles, such as those described above, have not 
been completely satisfactory. For example, articles which employ 
perforated films or breathable panels can exhibit excessive leakage of 
liquids from the article and can excessively soil the wearer's outer 
garments in the regions of the perforations or panels. In addition, when 
the absorbent material of the article becomes loaded with liquid, the wet 
absorbent can block the escape of moisture from the wearer's skin. Such 
absorbent garment designs have not been able to maintain a high level of 
breathability when wet to sufficiently reduce the hydration of the 
wearer's skin. As a result, the wearer's skin has remained susceptible to 
rashes, abrasion and irritation. 
SUMMARY OF THE INVENTION 
In response to the difficulties and problems discussed above, a new 
disposable absorbent article which has a high air exchange rate when wet, 
reduced levels of skin hydration and a reduced growth of microorganisms 
has been discovered. 
As used herein, reference to "air exchange" refers to the transfer of air 
from the interior of a diaper, when in use on a wearer, to the exterior of 
the diaper (ambient atmosphere). 
As used herein, a substantially liquid impermeable material is constructed 
to provide a hydrohead of at least about 60 cm (centimeters), desirably at 
least about 80 cm, and more desirably at least about 100 cm. A suitable 
technique for determining the hydrohead value is the Hydrostatic Pressure 
Test which is described in further detail herein below. 
As used herein, a substantially vapor permeable material is constructed to 
provide a water vapor transmission rate (WVTR) of at least about 100 
g/sq.m/24 hr, desirably at least about 250 g/sq.m/24 hr, and more 
desirably at least about 500 g/sq.m/24 hr. A suitable technique for 
determining the WVTR value is the Water Vapor Transmission Rate Test which 
is described in further detail herein below. 
In one aspect, the present invention relates to an absorbent article which 
comprises an absorbent, a front waist section, a rear waist section and an 
intermediate section which interconnects the front and rear waist 
sections. The absorbent article defines a Wet Air Exchange Rate of at 
least about 190 cubic centimeters per minute calculated according to the 
Tracer Gas Test set forth herein. In a particular embodiment, the article 
defines a Wet Air Exchange Rate of at least about 200, desirably at least 
about 225 and more desirably at least about 250 cubic centimeters per 
minute calculated according to the Tracer Gas Test. The absorbent article 
may further define a Dry Air Exchange Rate of at least about 525 cubic 
centimeters per minute calculated according to the Tracer Gas Test and/or 
a Skin Hydration Value of less than about 18 grams per square meter per 
hour calculated according to a Skin Hydration Test set forth herein. 
In another aspect, the present invention relates to a disposable absorbent 
article which comprises an absorbent, a front waist section, a rear waist 
section and an intermediate section which interconnects the front and rear 
waist sections. The absorbent article defines a Skin Hydration Value of 
less than about 18 grams per square meter per hour calculated according to 
the Skin Hydration Test set forth herein. In a particular embodiment, the 
absorbent article may define a Skin Hydration Value of less than about 15, 
desirably less than about 12 and more desirably less than about 10 grams 
per square meter per hour calculated according to the Skin Hydration Test. 
The absorbent article may further define a Wet Air Exchange Rate of at 
least about 190 cubic centimeters per minute and/or a Dry Air Exchange 
Rate of at least about 525 cubic centimeters per minute calculated 
according to the Tracer Gas Test as set forth herein. 
In another aspect, the present invention relates to a disposable absorbent 
article which defines a front waist section, a rear waist section, and an 
intermediate section which interconnects the front and rear waist 
sections. The absorbent article includes a) a vapor permeable backsheet 
which defines a Water Vapor Transmission Rate of at least about 1000 grams 
per square meter per 24 hours calculated according to a Water Vapor 
Transmission Test as set forth herein; b) a liquid permeable topsheet 
which is positioned in facing relation with the backsheet; and c) an 
absorbent body located between the backsheet and the topsheet which 
defines multiple zones of high air permeability for improved air exchange. 
In a particular embodiment, the zones of high air permeability in the 
absorbent body define a Frazier Porosity which is at least about 10 
percent greater than a Frazier Porosity of portions of the absorbent body 
adjacent to the zones of high air permeability. The absorbent article may 
further include a ventilation layer located between the backsheet and the 
absorbent body. 
In still another aspect, the present invention relates to a disposable 
absorbent article which defines a front waist section, a rear waist 
section, and an intermediate section which interconnects the front and 
rear waist sections. The absorbent article includes a) a vapor permeable, 
liquid impermeable backsheet which defines a Water Vapor Transmission Rate 
of at least about 1000 grams per square meter per 24 hours calculated 
according to a Water Vapor Transmission Test as set forth herein; b) a 
liquid permeable topsheet which is positioned in facing relation with the 
backsheet; c) an absorbent body located between the backsheet and the 
topsheet; d) a ventilation layer located between the backsheet and the 
absorbent body; and e) a surge management layer located between the 
topsheet and the absorbent body. In a particular embodiment, the absorbent 
body of the absorbent article includes a plurality of zones of high air 
permeability for improved air exchange which define a Frazier Porosity 
which is at least about 10 percent greater than a Frazier Porosity of 
portions of the absorbent body adjacent to the zones. 
In yet another aspect, the present invention relates to a disposable 
absorbent article which includes an absorbent, a front waist section, a 
rear waist section and an intermediate section which interconnects the 
front and rear waist sections. The absorbent article defines a C. albicans 
growth which is less than about 85 percent of the C. albicans growth of a 
control calculated according to a C. albicans Growth Test as set forth 
herein. In a particular embodiment, the C. albicans growth is less than 
about 80 percent and desirably less than about 60 percent of the C. 
albicans growth of the control calculated according to the C. albicans 
Growth Test. The absorbent article may further define a Wet Air Exchange 
Rate of at least about 190 cubic centimeters per minute and/or a Dry Air 
Exchange Rate of at least about 525 cubic centimeters per minute 
calculated according to the Tracer Gas Test as set forth herein and/or a 
Skin Hydration Value of less than about 18 grams per square meter per hour 
calculated according to the Skin Hydration Test set forth herein. 
The present invention advantageously provides improved absorbent articles 
which exhibit substantially reduced levels of hydration of the wearer's 
skin when in use compared to conventional absorbent articles. The reduced 
level of skin hydration promotes drier, more comfortable skin and renders 
the skin less susceptible to the growth of microorganisms. Thus, wearer's 
of absorbent articles made according to the present invention have reduced 
skin hydration which can lead to a reduction in the incidence of skin 
irritation and rash.

DETAILED DESCRIPTION OF THE INVENTION 
The following detailed description will be made in the context of a 
disposable diaper article which is adapted to be worn by infants about the 
lower torso. It is readily apparent, however, that the absorbent article 
of the present invention would also be suitable for use as other types of 
absorbent articles, such as feminine care pads, incontinence garments, 
training pants, and the like. 
The absorbent articles of present invention advantageously exhibit a 
substantially reduced level of hydration of the wearer's skin in use when 
compared to conventional absorbent articles. Thus, wearer's of absorbent 
articles of the different aspects of the present invention have reduced 
skin hydration which renders the skin less susceptible to the growth of 
microorganisms which can lead to a reduction in the incidence of skin 
irritation and rash. It has been discovered that the ability of the 
absorbent articles of the present invention to exhibit a low level of 
hydration on the wearer's skin during use depends, at least in part, on 
the ability of the absorbent article to achieve a high rate of air 
exchange within the article. Moreover, it has been further discovered that 
the achievement of such low levels of skin hydration further depends on 
the ability of the article to maintain the high rate of air exchange even 
when wet. 
The ability of an absorbent article to achieve high rates of air exchange 
both when dry and when wet has, for the purposes of this application, been 
quantified as the Dry Air Exchange Rate, the Wet Air Exchange Rate and the 
Wet Air Exchange Rate/Dry Air Exchange Rate ratio as determined according 
to the Tracer Gas Test set forth below. Briefly, the Tracer Gas Test 
involves injecting a tracer gas at a constant rate inside the absorbent 
article next to the skin of the wearer while the article is being worn. 
Simultaneously, the concentration of the tracer gas in the air space 
between the article and the wearer is measured by withdrawing a sample at 
the same constant rate as the injection. The air exchange is then 
determined based on mass balances of the tracer gas and the air within the 
space in question. 
To achieve the desired low levels of skin hydration, the absorbent articles 
of the different aspects of the present invention may be constructed to 
define a Wet Air Exchange Rate of at least about 190 cubic centimeters per 
minute, generally at least about 200 cubic centimeters per minute, 
desirably at least about 225 cubic centimeters per minute, more desirably 
at least about 250 cubic centimeters per minute, and even more desirably 
at least about 300 cubic centimeters per minute. For example, the 
absorbent articles may define a Wet Air Exchange Rate of from about 175 to 
about 1500 cubic centimeters per minute and desirably from about 225 to 
about 1500 cubic centimeters per minute. Absorbent articles which exhibit 
Wet Air Exchange Rates less than those above do not allow a sufficient 
amount of air exchange and undesirably result in increased levels of skin 
hydration. Such increased levels of skin hydration can render the skin 
more susceptible to the growth of microorganisms which can undesirably 
lead to an increase in the incidence of skin irritation and rash. 
The absorbent articles of the different aspects of the present invention 
may further be constructed to define a Dry Air Exchange Rate of at least 
about 525 cubic centimeters per minute, generally at least about 575 cubic 
centimeters per minute, desirably at least about 625 cubic centimeters per 
minute, more desirably at least about 675 cubic centimeters per minute, 
and even more desirably at least about 750 cubic centimeters per minute 
for improved performance. For example, the absorbent articles may define a 
Dry Air Exchange Rate of from about 525 to about 2500 cubic centimeters 
per minute and desirably from about 575 to about 2500 cubic centimeters 
per minute. Absorbent articles which exhibit Dry Air Exchange Rates less 
than those above do not allow a sufficient amount of air exchange and 
undesirably result in increased levels of skin hydration. Such increased 
levels of skin hydration can render the skin more susceptible to the 
growth of microorganisms which can undesirably lead to an increase in the 
incidence of skin irritation and rash. 
The absorbent articles of the different aspects of the present invention 
may further be constructed to define a Wet Air Exchange Rate/Dry Air 
Exchange Rate ratio of at least about 0.20, generally at least about 0.23, 
desirably at least about 0.27, and more desirably at least about 0.30 for 
improved performance. For example, the absorbent articles may define a Wet 
Air Exchange Rate/Dry Air Exchange Rate ratio of from about 0.20 to about 
1 and desirably from about 0.23 to about 1 for improved performance. 
The ability of the absorbent articles of the present invention to exhibit 
high levels of air exchange rate both when dry and when wet has led to 
reduced levels of skin hydration. The ability of an absorbent article to 
achieve a low level of skin hydration has, for the purposes of this 
application, been quantified as the Skin Hydration Value. As used herein, 
the term "Skin Hydration Value" refers to the value determined according 
to the Skin Hydration Test set forth below. In general, the Skin Hydration 
Value is determined by measuring the evaporative water loss on the skin of 
test subjects after wearing the wetted absorbent article for a set period 
of time. In particular embodiments, the absorbent articles of the 
different aspects of the present invention may be constructed to define a 
Skin Hydration Value of less than about 18 grams per square meter per 
hour, generally less than about 15 grams per square meter per hour, 
desirably less than about 12 grams per square meter per hour, more 
desirably less than about 10 grams per square meter per hour, even more 
desirably less than about 8 grams per square meter per hour, and yet even 
more desirably less than about 5 grams per square meter per hour for 
improved performance. For example, the absorbent articles of the present 
invention may define a Skin Hydration Value of from about 0.1 to about 18 
grams per square meter per hour and desirably from about 0.1 to about 12 
grams per square meter per hour. Absorbent articles which exhibit Skin 
Hydration Values greater than those above can render the skin more 
susceptible to the growth of microorganisms which can undesirably lead to 
an increase in the incidence of skin irritation and rash. 
The absorbent articles of the present invention may further exhibit reduced 
growth rates of microorganisms which can lead to a reduction in skin 
irritation. It is hypothesized that the reduced growth of microorganisms 
is a direct result of the increased breathability and air exchange within 
the articles of the present invention. The ability of an absorbent article 
to achieve a low rate of growth of microorganisms has, for the purposes of 
this application, been quantified as the C. albicans growth value since it 
is hypothesized that the presence of Candida albicans is directly related 
to the incidence of irritation and, in particular, rash. As used herein, 
the term "C. albicans growth" refers to the value determined according to 
the Candida albicans Growth Test set forth below. The Candida albicans 
Growth Test, in general, is a comparison of the C. albicans growth under a 
patch of the test absorbent article to the C. albicans growth under a 
control patch from a conventional absorbent article having a nonbreathable 
outer cover, i.e. an outer cover having a WVTR of less than 100 grams per 
square meter per 24 hours. 
In particular embodiments, the absorbent articles of the different aspects 
of the present invention may be constructed to define a C. albicans growth 
of less than about 85 percent, generally less than about 80 percent, 
desirably less than about 60 percent, more desirably less than about 40 
percent, and even more desirably less than about 20 percent of the C. 
albicans growth of the control for improved performance. For example, the 
absorbent articles of the present invention may define a C. albicans 
growth of less than about 2.5, desirably less than about 2.0, and more 
desirably less than about 1.75 log of C. albicans colony forming units. 
Absorbent articles which exhibit C. albicans growth values greater than 
those above can undesirably lead to an increase in the incidence of skin 
irritation and rash. Desirably, the above C. albicans growth values are 
obtained without the incorporation of antimicrobial agents into the 
absorbent articles which can be perceived by consumers in a negative 
manner. 
It has been discovered that acceptable, improved performance of absorbent 
articles can be achieved by selecting constructions having a combination 
of one or more of the above-described properties. For example, a given 
level of acceptable, improved performance may be achieved by employing an 
absorbent article which exhibits a Dry Air Exchange Rate of at least about 
525 cubic centimeters per minute and a Wet Air Exchange Rate of at least 
about 175 cubic centimeters per minute, and desirably a Dry Air Exchange 
Rate of at least about 675 cubic centimeters per minute and a Wet Air 
Exchange Rate of at least about 200 cubic centimeters per minute. 
Alternatively, improved performance can be achieved by employing an 
absorbent article which exhibits a Wet Air Exchange Rate of at least about 
175 cubic centimeters per minute and a Skin Hydration Value of less than 
about 18 grams per square meter per hour, and desirably a Wet Air Exchange 
Rate of at least about 200 cubic centimeters per minute and a Skin 
Hydration Value of less than about 12 grams per square meter per hour. 
Still further, it has been discovered that improved performance can be 
achieved by employing absorbent articles having a Dry Air Exchange Rate of 
at least about 525 cubic centimeters per minute and a Wet Air Exchange 
Rate/Dry Air Exchange Rate ratio of at least about 0.20 and desirably a 
Dry Air Exchange Rate of at least about 625 cubic centimeters per minute 
and a Wet Air Exchange Rate/Dry Air Exchange Rate ratio of at least about 
0.23. 
Examples of suitable constructions of absorbent articles for use in the 
present invention are described below and representatively illustrated in 
FIGS. 1-6. FIG. 1 is a representative plan view of an integral absorbent 
garment article, such as disposable diaper 10, of the present invention in 
its flat-out, uncontracted state (i.e., with all elastic induced gathering 
and contraction removed). Portions of the structure are partially cut away 
to more clearly show the interior construction of diaper 10, and the 
surface of the diaper which contacts the wearer is facing the viewer. FIG. 
2 representatively shows a sectional view of the absorbent article of FIG. 
1 taken along line 2--2. With reference to FIGS. 1 and 2, the disposable 
diaper 10 generally defines a front waist section 12, a rear waist section 
14, and an intermediate section 16 which interconnects the front and rear 
waist sections. The front and rear waist sections include the general 
portions of the article which are constructed to extend substantially over 
the wearer's front and rear abdominal regions, respectively, during use. 
The intermediate section of the article includes the general portion of 
the article which is constructed to extend through the wearer's crotch 
region between the legs. 
The absorbent article includes a vapor permeable backsheet 20, a liquid 
permeable topsheet 22 positioned in facing relation with the backsheet 20, 
and an absorbent body 24, such as an absorbent pad, which is located 
between the backsheet 20 and the topsheet 22. The backsheet 20 defines a 
length and a width which, in the illustrated embodiment, coincide with the 
length and width of the diaper 10. The absorbent body 24 generally defines 
a length and width which are less than the length and width of the 
backsheet 20, respectively. Thus, marginal portions of the diaper 10, such 
as marginal sections of the backsheet 20, may extend past the terminal 
edges of the absorbent body 24. In the illustrated embodiments, for 
example, the backsheet 20 extends outwardly beyond the terminal marginal 
edges of the absorbent body 24 to form side margins and end margins of the 
diaper 10. The topsheet 22 is generally coextensive with the backsheet 20 
but may optionally cover an area which is larger or smaller than the area 
of the backsheet 20, as desired. The backsheet 20 and topsheet 22 are 
intended to face the garment and body of the wearer, respectively, while 
in use. 
The permeability of the backsheet is configured to enhance the 
breathability of the absorbent article to reduce the hydration of the 
wearer's skin during use without allowing excessive condensation of vapor, 
such as urine, on the garment facing surface of the backsheet 20 which can 
undesirably dampen the wearer's clothes. 
To provide improved fit and to help reduce leakage of body exudates from 
the diaper 10, the diaper side margins and end margins may be elasticized 
with suitable elastic members, such as single or multiple strands of 
elastic. The elastic strands may be composed of natural or synthetic 
rubber and may optionally be heat shrinkable or heat elasticizable. For 
example, as representatively illustrated in FIGS. 1 and 2, the diaper 10 
may include leg elastics 26 which are constructed to operably gather and 
shirr the side margins of the diaper 10 to provide elasticized leg bands 
which can closely fit around the legs of the wearer to reduce leakage and 
provide improved comfort and appearance. Similarly, waist elastics 28 can 
be employed to elasticize the end margins of the diaper 10 to provide 
elasticized waists. The waist elastics are configured to operably gather 
and shirr the waist sections to provide a resilient, comfortably close fit 
around the waist of the wearer. In the illustrated embodiments, the 
elastic members are illustrated in their uncontracted, stretched condition 
for the purpose of clarity. 
Fastening means, such as hook and loop fasteners 30, are employed to secure 
the diaper on a wearer. Alternatively, other fastening means, such as 
buttons, pins, snaps, adhesive tape fasteners, cohesives, 
mushroom-and-loop fasteners, or the like, may be employed. 
The diaper 10 may further 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 may include a ventilation 
layer 32 located between the absorbent body 24 and the backsheet 20 to 
insulate the backsheet 20 from the absorbent body 24 to improve air 
circulation and effectively reduce the dampness of the garment facing 
surface of the backsheet 20. The ventilation layer 32 may also assist in 
distributing fluid exudates to portions of the absorbent body 24 which do 
not directly receive the insult. The diaper 10 may also include a surge 
management layer 34 located between the topsheet 22 and the absorbent body 
24 to prevent pooling of the fluid exudates and further improve air 
exchange and distribution of the fluid exudates within the diaper 10. 
The diaper 10 may be of various suitable shapes. For example, the diaper 
may have an overall rectangular shape, T-shape or an approximately 
hour-glass shape. In the shown embodiment, the diaper 10 has a generally 
I-shape. The diaper 10 further defines a longitudinal direction 36 and a 
lateral direction 38. Other suitable diaper components which may be 
incorporated on absorbent articles of the present invention include 
containment flaps, waist flaps, elastomeric side panels, and the like 
which are generally known to those skilled in the art. 
Examples of diaper configurations suitable for use in connection with the 
instant application which may include other diaper components suitable for 
use on diapers are described in U.S. Pat. No. 4,798,603 issued Jan. 17, 
1989, to Meyer et al.; U.S. Pat. No. 5,176,668 issued Jan. 5, 1993, to 
Bernardin; U.S. Pat. No. 5,176,672 issued Jan. 5, 1993, to Bruemmer et 
al.; U.S. Pat. No. 5,192,606 issued Mar. 9, 1993, to Proxmire et al., and 
U.S. Pat. No. 5,509,915 issued Apr. 23, 1996 to Hanson et al., the 
disclosures of which are herein incorporated by reference. 
The various components of the diaper 10 are integrally assembled together 
employing various types of suitable attachment means, such as adhesive, 
sonic bonds, thermal bonds or combinations thereof. In the shown 
embodiment, for example, the topsheet 22 and backsheet 20 are assembled to 
each other and to the absorbent body 24 with lines of adhesive, such as a 
hot melt, pressure-sensitive adhesive. Similarly, other diaper components, 
such as the elastic members 26 and 28, fastening members 30, and 
ventilation and surge layers 32 and 34 may be assembled into the diaper 
article by employing the above-identified attachment mechanisms. 
The backsheet 20 of the diaper 10, as representatively illustrated in FIGS. 
1 and 2, is composed of a substantially vapor permeable material. The 
backsheet 20 is generally constructed to be permeable to at least water 
vapor and has a water vapor transmission rate of at least about 1000 
g/sq.m/24 hr., desirably at least about 1500 g/sq.m/24 hr, more desirably 
at least about 2000 g/sq.m/24 hr., and even more desirably at least about 
3000 g/sq.m/24. For example, the backsheet 20 may define a water vapor 
transmission rate of from about 1000 to about 6000 g/sq.m/24 hr. Materials 
which have a water vapor transmission rate less than those above do not 
allow a sufficient amount of air exchange and undesirably result in 
increased levels of skin hydration. 
The backsheet 20 is also desirably substantially liquid impermeable. For 
example, the backsheet may be constructed to provide a hydrohead value of 
at least about 60 cm, desirably at least about 80 cm, and more desirably 
at least about 100 cm when subjected to the Hydrostatic Pressure Test. 
Materials which have hydrohead values less than those above undesirably 
result in the strike through of liquids, such as urine, during use. Such 
fluid strike through can undesirably result in a damp, clammy feeling on 
the backsheet 20 during use. 
The backsheet 20 may be composed of any suitable materials which either 
directly provide the above desired levels of liquid impermeability and air 
permeability or, in the alternative, materials which can be modified or 
treated in some manner to provide such levels. In one embodiment, the 
backsheet 20 may be a nonwoven fibrous web constructed to provide the 
required level of liquid impermeability. For example, a nonwoven web 
composed of spunbonded or meltblown polymer fibers may be selectively 
treated with a water repellent coating or laminated with a liquid 
impermeable, vapor permeable polymer film to provide the backsheet 20. In 
a particular embodiment of the invention, the backsheet 20 may comprise a 
nonwoven web composed of a plurality of randomly deposited hydrophobic 
thermoplastic meltblown fibers which are sufficiently bonded or otherwise 
connected to one another to provide a substantially vapor permeable and 
substantially liquid impermeable web. The backsheet 20 may also comprise a 
vapor permeable nonwoven layer which has been partially coated or 
otherwise configured to provide liquid impermeability in selected areas. 
Examples of suitable materials for the backsheet 20 are also described in 
U.S. Pat. No. 5,482,765 issued Jan. 9, 1996 in the name of Bradley et al. 
and entitled "NONWOVEN FABRIC LAMINATE WITH ENHANCED BARRIER PROPERTIES"; 
U.S. patent application Ser. No. 08/622,903 filed Mar. 29, 1996 in the 
name of Odorzynski et al. and entitled "ABSORBENT ARTICLE HAVING A 
BREATHABILITY GRADIENT"; U.S. patent application Ser. No. 08/668,418 filed 
Jun. 21, 1996, in the name of Good et al. and entitled "ABSORBENT ARTICLE 
HAVING A COMPOSITE BREATHABLE BACKSHEET"; and U.S. patent application Ser. 
No. 08/882,712 filed Jun. 25, 1997, in the name of McCormack et al. and 
entitled "LOW GAUGE FILMS AND FILM/NONWOVEN LAMINATES", the disclosures of 
which are herein incorporated by reference. 
In a particular embodiment, the backsheet 20 is provided by a microporous 
film/nonwoven laminate material comprising a spunbond nonwoven material 
laminated to a microporous film. The spunbond nonwoven comprises filaments 
of about 1.8 denier extruded from a copolymer of ethylene with about 3.5 
weight percent propylene and defines a basis weight of from about 17 to 
about 25 grams per square meter. The film comprises a cast coextruded film 
having calcium carbonate particles therein and defines a basis weight of 
about 58 grams per square meter prior to stretching. The film is 
preheated, stretched and annealed to form the micropores and then 
laminated to the spunbond nonwoven. The resulting microporous 
film/nonwoven laminate based material has a basis weight of from about 30 
to about 60 grams per square meter and a water vapor transmission rate of 
from about 3000 to about 6000 g/sq.m/24 hr. Examples of such film/nonwoven 
laminate materials are described in more detail in U.S. patent application 
Ser. No. 08/882,712 filed Jun. 25, 1997, in the name of McCormack et al. 
and entitled "LOW GAUGE FILMS AND FILM/NONWOVEN LAMINATES ", the 
disclosure of which has been incorporated by reference. 
The topsheet 22, as representatively illustrated in FIGS. 1 and 2, suitably 
presents a bodyfacing surface which is compliant, soft feeling, and 
nonirritating to the wearer's skin. Further, the topsheet 22 may be less 
hydrophilic than the absorbent body 24, to present a relatively dry 
surface to the wearer, and may be sufficiently porous to be liquid 
permeable, permitting liquid to readily penetrate through its thickness. A 
suitable topsheet 22 may be manufactured from a wide selection of web 
materials, such as porous foams, reticulated foams, apertured plastic 
films, natural fibers (for example, wood or cotton fibers), synthetic 
fibers (for example, polyester or polypropylene fibers), or a combination 
of natural and synthetic fibers. The topsheet 22 is suitably employed to 
help isolate the wearer's skin from liquids held in the absorbent body 24. 
Various woven and nonwoven fabrics can be used for the topsheet 22. For 
example, the topsheet may be composed of a meltblown or spunbonded web of 
polyolefin fibers. The topsheet may also be a bonded-carded web composed 
of natural and/or synthetic fibers. The topsheet may be composed of a 
substantially hydrophobic material, and the hydrophobic material may, 
optionally, be treated with a surfactant or otherwise processed to impart 
a desired level of wettability and hydrophilicity. In a particular 
embodiment of the present invention, the topsheet 22 comprises a nonwoven, 
spunbond, polypropylene fabric composed of about 2.8-3.2 denier fibers 
formed into a web having a basis weight of about 22 grams per square meter 
and a density of about 0.06 gram per cubic centimeter. Such a topsheet 22 
may be surface treated with an effective amount of a surfactant, such as 
about 0.3 weight percent of a surfactant commercially available from 
Hodgson Textile Chemicals Co. under the trade designation AHCOVEL BASE 
N-62. 
The absorbent body 24 of the diaper 10, as representatively illustrated in 
FIGS. 1 and 2, may suitably comprise a matrix of hydrophilic fibers, such 
as a web of cellulosic fluff, mixed with particles of a high-absorbency 
material commonly known as superabsorbent material. In a particular 
embodiment, the absorbent body 24 comprises a matrix of cellulosic fluff, 
such as wood pulp fluff, and superabsorbent hydrogel-forming particles. 
The wood pulp fluff may be exchanged with synthetic, polymeric, meltblown 
fibers or with a combination of meltblown fibers and natural fibers. The 
superabsorbent particles may be substantially homogeneously mixed with the 
hydrophilic fibers or may be nonuniformly mixed. Alternatively, the 
absorbent body 24 may comprise a laminate of fibrous webs and 
superabsorbent material or other suitable means of maintaining a 
superabsorbent material in a localized area. 
The absorbent body 24 may have any of a number of shapes. For example, the 
absorbent core may be rectangular, I-shaped, or T-shaped. It is generally 
preferred that the absorbent body 24 be narrower in the intermediate 
section than in the front or rear waist sections of the diaper 10. The 
absorbent body 24 may be provided by a single layer or, in the 
alternative, may be provided by multiple layers, all of which need not 
extend the entire length and width of the absorbent body 24. In a 
particular aspect of the invention, the absorbent body 24 can be generally 
T-shaped with the laterally extending cross-bar of the "T" generally 
corresponding to the front waist section 12 of the absorbent article for 
improved performance, especially for male infants. In the illustrated 
embodiments, for example, the absorbent body 24 across the front waist 
section 12 of the article has a cross-directional width of about 18 
centimeters, the narrowest portion of the intermediate section 16 has a 
width of about 7.5 centimeters and in the rear waist section 14 has a 
width of about 11.4 centimeters. 
The size and the absorbent capacity of absorbent body 24 should be 
compatible with the size of the intended wearer and the liquid loading 
imparted by the intended use of the absorbent article. Further, the size 
and the absorbent capacity of the absorbent body 24 can be varied to 
accommodate wearers ranging from infants through adults. In addition, it 
has been found that with the present invention, the densities and/or basis 
weights of the absorbent body 24 can be varied. In a particular aspect of 
the invention, the absorbent body 24 has an absorbent capacity of at least 
about 300 grams of synthetic urine. 
In embodiments wherein the absorbent body 24 includes the combination of 
hydrophilic fibers and high-absorbency particles, the hydrophilic fibers 
and high-absorbency particles can form an average basis weight for the 
absorbent body 24 which is within the range of about 400-900 grams per 
square meter. In certain aspects of the invention, the average composite 
basis weight of such an absorbent body 24 is within the range of about 
500-800 grams per square meter, and preferably is within the range of 
about 550-750 grams per square meter to provide the desired performance. 
To provide the desired thinness dimension to the various configurations of 
the absorbent article of the invention, the absorbent body 24 can be 
configured with a bulk thickness which is not more than about 0.6 
centimeters. Preferably, the bulk thickness is not more than about 0.53 
centimeters, and more preferably is not more than about 0.5 centimeters to 
provide improved benefits. The bulk thickness is determined under a 
restraining pressure of 0.2 psi (1.38 kPa). 
The high-absorbency material can be selected from natural, synthetic, and 
modified natural polymers and materials. The high-absorbency materials can 
be inorganic materials, such as silica gels, or organic compounds, such as 
crosslinked polymers. The term "crosslinked" refers to any means for 
effectively rendering normally water-soluble materials substantially water 
insoluble but swellable. Such means can include, for example, physical 
entanglement, crystalline domains, covalent bonds, ionic complexes and 
associations, hydrophilic associations such as hydrogen bonding, and 
hydrophobic associations or Van der Waals forces. 
Examples of synthetic, polymeric, high-absorbency materials include the 
alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic 
acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers 
with vinyl ethers and alpha-olefins, poly(vinyl pyrrolidone), poly(vinyl 
morpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. 
Further polymers suitable for use in the absorbent core include natural 
and modified natural polymers, such as hydrolyzed acrylonitrile-grafted 
starch, acrylic acid grafted starch, methyl cellulose, carboxymethyl 
cellulose, hydroxypropyl cellulose, and the natural gums, such as 
alginates, xanthum gum, locust bean gum, and the like. Mixtures of natural 
and wholly or partially synthetic absorbent polymers can also be useful in 
the present invention. 
The high absorbency material may be in any of a wide variety of geometric 
forms. As a general rule, it is preferred that the high absorbency 
material be in the form of discrete particles. However, the high 
absorbency material may also be in the form of fibers, flakes, rods, 
spheres, needles, or the like. In general, the high absorbency material is 
present in the absorbent body in an amount of from about 5 to about 90 
weight percent, desirably in an amount of at least about 30 weight 
percent, and even more desirably in an amount of at least about 50 weight 
percent based on a total weight of the absorbent body 24. For example, in 
a particularly embodiment, the absorbent body 24 may comprise a laminate 
which includes at least about 50 weight percent and desirably at least 
about 70 weight percent of high-absorbency material overwrapped by a 
fibrous web or other suitable means of maintaining the high-absorbency 
material in a localized area. 
An example of high-absorbency material suitable for use in the present 
invention is SANWET IM 3900 polymer available from Hoechst Celanese, a 
business having offices in Portsmouth, Va. Other suitable superabsorbents 
may include W45926 or FAVOR SXM 880 polymer obtained from Stockhausen, a 
business having offices in Greensboro, N.C. 
Optionally, a substantially hydrophilic tissue wrapsheet (not illustrated) 
may be employed to help maintain the integrity of the structure of the 
absorbent body 24. The tissue wrap sheet is typically placed about the 
absorbent body over at least the two major facing surfaces thereof and 
composed of an absorbent cellulosic material, such as creped wadding or a 
high wet-strength tissue. In one aspect of the invention, the tissue wrap 
can be configured to provide a wicking layer which helps to rapidly 
distribute liquid over the mass of absorbent fibers comprising the 
absorbent body. 
The absorbent body 24 of the different aspects of the present invention 
further includes a plurality of zones of high air permeability which allow 
air and vapors to readily pass through the absorbent body 24 and through 
the vapor permeable backsheet 20 out of the diaper 10 into ambient air. 
For example, as representatively illustrated in FIGS. 1 and 2, the 
absorbent body 24 may include a plurality of air passageways 40 which 
provide the absorbent body 24 with the zones or regions of high air 
permeability 42. In the illustrated embodiment, the portions of the 
absorbent body 24 adjacent the air passageways 40 provide zones or regions 
of high absorption 44. The zones of high air permeability 42 are designed 
to provide the maximum air exchange from the absorbent body 24 while the 
zones of high absorption 44 are designed to receive and hold the majority 
of the body exudates. The absorbent body 24 may define any number of zones 
of high air permeability 42 which provides the improved air exchange. 
Desirably, the absorbent body 24 defines at least 3 and more desirably at 
least 5 different zones of high air permeability 42 for improved 
performance. 
The zones of high air permeability 42, such as the air passageways 40 as 
representatively illustrated in FIGS. 1 and 2, are configured to enhance 
the breathability of the article to reduce the hydration of the wearer's 
skin during use without allowing excessive condensation of vapor, such as 
urine, on the garment facing surface of the backsheet 20. Such 
condensation of vapor on the outer surface of the diaper 10 can 
undesirably dampen the wearer's clothes. The zones of high air 
permeability 42 are generally located in the area of the diaper over which 
air and vapor can transfer from the topsheet 22, through the absorbent 
body 24 and any other intervening layer or layers of material, and out the 
vapor permeable backsheet 20. For example, the zones of high air 
permeability 42 may be located throughout the entire absorbent body 24 or 
may be selectively located in those regions of the absorbent body 24 which 
provide the maximum air exchange, such as the intermediate section 16 of 
the diaper 20. In a particular embodiment, the zones of high air 
permeability 42 are located in the front and intermediate sections 12 and 
16, respectively, of the diaper 10 for improved air exchange. 
The zones of high absorption 44, on the other hand, are not designed to 
transfer a high level of air and vapor from the interior of the diaper. 
Thus, the air exchange from the topsheet 22 of the diaper 10 to the 
backsheet 20 of the diaper and into the ambient atmosphere (exterior of 
the diaper) occurs generally through the absorbent body 24 in the zones of 
high air permeability 42. Some air exchange through the absorbent body 24 
can also occur in the zones of high absorption 44 to a limited degree. 
The zones of high air permeability may have any desired configuration 
including rectangular, circular, hourglass, oval, and the like, and may 
also include selected longitudinal or lateral strips or multiple regions 
which may be intermittently located. For example, in FIGS. 1 and 2, the 
zones of high air permeability 42 are provided by a plurality of air 
passageways 40 or apertures through the absorbent body 24 which have a 
generally circular configuration. In such a configuration, the zones of 
high absorption 44 comprise the non-apertured portions of the absorbent 
body 24 between the air passageways 40. 
The zones of high air permeability 42 may have any desired dimensions which 
effectively provide improved air exchange while preventing excessive 
condensation of vapor from the absorbent body 24 through and onto the 
garment facing surface of the backsheet 20. Desirably, the zones of high 
air permeability 42 may define a total area of from about 5 to about 75 
percent, more desirably at least about 10 percent, even more desirably 
from about 10 to about 70 percent, and still more desirably from about 10 
to about 60 percent of the total surface area of the absorbent body 24 of 
the diaper 10. For example, in a diaper intended for use on a medium sized 
infant, the zones of high air permeability 42 may define a total area of 
from about 6 to about 90 square centimeters. 
When the total area of the zones of high air permeability 42 is greater 
than the above amounts, the diaper 10 may exhibit an undesirable amount of 
condensation of vapor on the exposed, garment facing surface of the 
backsheet 20 undesirably resulting in a clammy feeling on the outer 
surface of the diaper. Whereas, when the total area of the zones of high 
air permeability 42 is less than the above amounts, the diaper 10 may 
exhibit a low level of air exchange resulting in high levels of skin 
hydration which can undesirably lead to skin irritation and rash. 
The zones of high air permeability 42 of the absorbent body 24 of the 
diaper 10, as representatively illustrated in FIGS. 1 and 2, are 
constructed to be substantially permeable to at least air and preferably 
permeable to water vapor. For example, the zones of high air permeability 
42 of the absorbent body 24 define a Frazier Porosity value which is at 
least about 10 percent, more desirably at least about 20 percent and even 
more desirably at least about 50 percent greater than the Frazier Porosity 
value of the zones of high absorption 44 of the absorbent body 24. As used 
herein, the term "Frazier Porosity" refers to the value determined 
according to the Frazier Porosity Test set forth below. When the zones of 
high air permeability exhibit Frazier Porosity values less than those 
indicated above, the diaper 10 may exhibit a low level of air exchange 
resulting in high levels of skin hydration which can undesirably lead to 
skin irritation and rash. 
The zones of high air permeability may be provided in a variety of ways. 
The zones of high air permeability 42 may be integral portions of the 
absorbent body 24 of the absorbent article or may be provided by 
apertures, holes or open spaces in the absorbent body 24. For example, 
portions of the absorbent body 24 may be discontinuous or removed to 
provide the zones 42. Alternatively, the zones of high air permeability 42 
may be provided by portions of the absorbent body 24 which are constructed 
to absorb less fluid exudates thereby resulting in improved air flow 
through such portions in use. For example, portions of the absorbent body 
24 may be void of or contain substantially less high-absorbency material 
than other portions of the absorbent body 24 to provide such improved air 
flow. Portions of the absorbent body 24 may otherwise be treated or coated 
with a solution which renders them hydrophobic to provide the zones of 
high air permeability 42 in selected areas. In other alternative 
configurations, the zones of high air permeability 42 may be provided by 
creating voids or holes in the absorbent body 24 and placing other 
materials having a higher air permeability than the absorbent body 24, 
such as those materials described below as being suitable for the surge 
management layer 34, in the holes or voids. 
Examples of several configurations of the absorbent body 24 according to 
different aspects of the present invention are representatively 
illustrated in FIGS. 1-6. For example, in FIGS. 1 and 2, the zones of high 
air permeability 42 in the absorbent body 24 are provided by a plurality 
of air passageways 40 or apertures through the absorbent body 24. In the 
illustrated embodiment, the air passageways 40 are intermittently 
positioned along the entire length and width of the absorbent body 24. The 
illustrated air passageways 40 are circular and define a diameter of about 
1.27 centimeters and a total open area of about 12 percent of a total 
surface area of the absorbent body 24. 
In FIGS. 3 and 4, the absorbent body 24 is in the form of discrete segments 
46 which are spaced apart along the longitudinal direction 36 of the 
diaper 10. In such a configuration, the zones of high air permeability 42 
are provided by the spaces between the discrete segments 46 of the 
absorbent body 24. The absorbent body 24 may include any number of 
segments 46 having a variety of 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 
define a width which is less than a width of the absorbent body 24 which, 
in the illustrated embodiment, is defined by the width of the surge 
management layer 34 and the ventilation layer 32 as described below. 
Alternatively, the segments 46 may define a width which is substantially 
equal to a width of the absorbent body 24. To assist in maintaining the 
segments 46 in the spaced apart relationship, the segments 46 can be 
contained between two sheets of material such as wrapsheet (not shown) or 
the surge management layer 34 and the ventilation layer 32. In the 
illustrated embodiment, the segments 46 include a laminate of 
high-absorbency material between two sheets or layers of material and the 
zones of high air permeability 42 provided by the spaces between the 
segments 46 define an open area of about 40 percent of a total surface are 
of the absorbent body 24. 
In FIGS. 5 and 6, the zones of high air permeability 42 in the absorbent 
body 24 are provided by a plurality of air passageways 40 or apertures 
through the absorbent body 24 similar to the embodiment illustrated in 
FIGS. 1 and 2. However, in the embodiment illustrated in FIGS. 5 and 6, 
the air passageways 40 are located in the absorbent body 24 in the front 
waist section 12 and the intermediate section 16 of the diaper 10 and not 
in the rear waist section 14. Moreover, in the embodiment illustrated in 
FIGS. 5 and 6, the absorbent body 24 includes an upper layer 48 and a 
lower layer 50 with the upper layer 48 extending only along a portion of 
the length of the absorbent body 24. In such a configuration, the majority 
of the absorbent body 24 can be located in the front waist and 
intermediate sections 12 and 16 of the diaper 10 for improved absorption 
and reduced cost. The illustrated air passageways 40 are circular and 
define a diameter of about 1.27 centimeters and a total open area of about 
12 percent of a total surface area of the absorbent body 24. 
Due to the thinness of absorbent body 24 and the high absorbency material 
within the absorbent body 24, the liquid uptake rates of the absorbent 
body 24, by itself, may be too low, or may not be adequately sustained 
over multiple insults of liquid into the absorbent body 24. To improve the 
overall liquid uptake and air exchange, the diaper of the different 
aspects of the present invention may further include a porous, 
liquid-permeable layer of surge management material 34, as 
representatively illustrated in FIGS. 1 and 2. The surge management layer 
34 is typically less hydrophilic than the absorbent body 24, and has an 
operable level of density and basis weight to quickly collect and 
temporarily hold liquid surges, to transport the liquid from its initial 
entrance point and to substantially completely release the liquid to other 
parts of the absorbent body 24. This configuration can help prevent the 
liquid from pooling and collecting on the portion of the absorbent garment 
positioned against the wearer's skin, thereby reducing the feeling of 
wetness by the wearer. The structure of the surge management layer 34 also 
generally enhances the air exchange within the diaper 10. 
Various woven and nonwoven fabrics can be used to construct the surge 
management layer 34. For example, the surge management layer 34 may be a 
layer composed of a meltblown or spunbonded web of synthetic fibers, such 
as polyolefin fibers. The surge management layer 34 may also be a 
bonded-carded-web or an airlaid web composed of natural and synthetic 
fibers. The bonded-carded-web may, for example, be a thermally bonded web 
which is bonded using low melt binder fibers, powder or adhesive. The webs 
can optionally include a mixture of different fibers. The surge management 
layer 34 may be composed of a substantially hydrophobic material, and the 
hydrophobic material may optionally be treated with a surfactant or 
otherwise processed to impart a desired level of wettability and 
hydrophilicity. In a particular embodiment, the surge management layer 34 
includes a hydrophobic, nonwoven material having a basis weight of from 
about 30 to about 120 grams per square meter. 
For example, in a particular embodiment, the surge management layer 34 may 
comprise a bonded-carded-web, nonwoven fabric which includes bicomponent 
fibers and which defines an overall basis weight of about 83 grams per 
square meter. The surge management layer 34 in such a configuration can be 
a homogeneous blend composed of about 60 weight percent 
polyethylene/polyester (PE/PET), sheath-core bicomponent fibers which have 
a fiber denier of about 3 d and about 40 weight percent single component 
polyester fibers which have a fiber denier of about 6 d and which have 
fiber lengths of from about 3.8 to about 5.08 centimeters. 
In the illustrated embodiments, the surge management layer 34 is arranged 
in a direct, contacting liquid communication with the absorbent body 24. 
The surge management layer 34 may be operably connected to the topsheet 22 
with a conventional pattern of adhesive, such as a swirl adhesive pattern. 
In addition, the surge management layer 34 may be operably connected to 
the absorbent body 24 with a conventional pattern of adhesive. The amount 
of adhesive add-on should be sufficient to provide the desired levels of 
bonding, but should be low enough to avoid excessively restricting the 
movement of liquid from the topsheet 22, through the surge management 
layer 34 and into the absorbent body 24. 
The absorbent body 24 is positioned in liquid communication with surge 
management layer 34 to receive liquids released from the surge management 
layer, and to hold and store the liquid. In the shown embodiments, the 
surge management layer 34 comprises a separate layer which is positioned 
over another, separate layer comprising the absorbent body 24, thereby 
forming a dual-layer arrangement. The surge management layer 34 serves to 
quickly collect and temporarily hold discharged liquids, to transport such 
liquids from the point of initial contact and spread the liquid to other 
parts of the surge management layer 34, and then to substantially 
completely release such liquids into the layer or layers comprising the 
absorbent body 24. 
The surge management layer 34 can be of any desired shape. Suitable shapes 
include for example, circular, rectangular, triangular, trapezoidal, 
oblong, dog-boned, hourglass-shaped, or oval. In certain embodiments, for 
example, the surge management layer can be generally rectangular-shaped. 
In the illustrated embodiments, the surge management layer 34 is 
coextensive with the absorbent body 24. Alternatively, the surge 
management layer 34 may extend over only a part of the absorbent body 24. 
Where the surge management layer 34 extends only partially along the 
length of the absorbent body 24, the surge management layer 34 may be 
selectively positioned anywhere along the absorbent body 24. For example, 
the surge management layer 34 may function more efficiently when it is 
offset toward the front waist section 12 of the garment. The surge 
management layer 34 may also be approximately centered about the 
longitudinal center line of the absorbent body 24. 
Additional materials suitable for the surge management layer 34 are set 
forth in U.S. Pat. No. 5,486,166 issued Jan. 23, 1996 in the name of C. 
Ellis et al. and entitled "FIBROUS NONWOVEN WEB SURGE LAYER FOR PERSONAL 
CARE ABSORBENT ARTICLES AND THE LIKE"; U.S. Pat. No. 5,490,846 issued Feb. 
13, 1996 in the name of Ellis et al. and entitled "IMPROVED SURGE 
MANAGEMENT FIBROUS NONWOVEN WEB FOR PERSONAL CARE ABSORBENT ARTICLES AND 
THE LIKE"; and U.S. Pat. No. 5,364,382 issued Nov. 15, 1994 in the name of 
Latimer et al. and entitled "ABSORBENT STRUCTURE HAVING IMPROVED FLUID 
SURGE MANAGEMENT AND PRODUCT INCORPORATING SAME", the disclosures of which 
are hereby incorporated by reference. 
As representatively illustrated in FIGS. 1 and 2, the diaper 10 may also 
include a ventilation layer 32 located between the backsheet 20 and the 
absorbent body 24. The ventilation layer 32 serves to facilitate the 
movement of air within and through the diaper 10 and prevent the backsheet 
20 from being in surface to surface contact with at least a portion of the 
absorbent body 24. Specifically, the ventilation layer 32 serves as a 
conduit through which air and water vapor can move from the absorbent body 
24 through the vapor permeable backsheet 20. 
The ventilation layer 32 may be formed from materials described above as 
being suitable for the surge management layer 34 such as nonwoven, (e.g., 
spunbond, meltblown or carded), woven, or knitted fibrous webs composed of 
natural fibers and/or synthetic polymeric fibers. Suitable fibers include, 
for example, acrylic fibers, polyolefin fibers, polyester fibers, or 
blends thereof. The ventilation layer 32 may also be formed from a porous 
foam material such as an open-celled polyolefin foam, a reticulated 
polyurethane foam, and the like. The ventilation layer 32 may include a 
single layer of material or a composite of two or more layers of material. 
In a particular embodiment, the ventilation layer 32 includes a 
hydrophobic, nonwoven material having a thickness of at least about 0.10 
centimeters determined under a restraining pressure of 0.05 psi (0.34 kPa) 
and a basis weight of from about 20 to about 120 grams per square meter. 
For example, the ventilation layer 32 may comprise a bonded-carded-web, 
nonwoven fabric which includes bicomponent fibers and which defines an 
overall basis weight of about 83 grams per square meter. The ventilation 
layer 32 in such a configuration can be a homogeneous blend composed of 
about 60 weight percent polyethylene/polyester (PE/PET), sheath-core 
bicomponent fibers which have a fiber denier of about 3 d and about 40 
weight percent single component polyester fibers which have a fiber denier 
of about 6 d and which have fiber lengths of from about 3.8 to about 5.08 
centimeters. 
The ventilation layer 32 can be of any desired shape. Suitable shapes 
include for example, circular, rectangular, triangular, trapezoidal, 
oblong, dog-boned, hourglass-shaped, or oval. The ventilation layer 32 may 
extend beyond, completely over or partially over the absorbent body 24. 
For example, the ventilation layer 32 may suitably be located over the 
intermediate section 16 of the diaper 10 and be substantially centered 
side-to-side with respect to the longitudinal centerline 36 of the diaper 
10. It is generally desired that the entire absorbent body 24 be overlaid 
with the ventilation layer 32 to prevent substantially all surface to 
surface contact between the backsheet 20 and the absorbent body 24. In the 
illustrated embodiments, the ventilation layer 32 is coextensive with the 
absorbent body 24. This allows for the maximum degree of air exchange with 
minimal dampness on the garment facing surface of the backsheet 20. 
In the illustrated embodiments, the ventilation layer 32 is arranged in a 
direct, contacting liquid communication with the absorbent body 24. The 
ventilation layer 32 may be operably connected to the backsheet 20 with a 
conventional pattern of adhesive, such as a swirl adhesive pattern. In 
addition, the ventilation layer 32 may be operably connected to the 
absorbent body 24 with a conventional pattern of adhesive. The amount of 
adhesive add-on should be sufficient to provide the desired levels of 
bonding, but should be low enough to avoid excessively restricting the 
movement of air and vapor from the absorbent body 24 and through the 
backsheet 20. 
The ventilation layer 32 may further serve to quickly collect and 
temporarily hold discharged liquids, which pass through the absorbent body 
24 and, in particular, through the zones of high air permeability 42 
within the absorbent body 24. The ventilation layer 32 may then transport 
such liquids from the point of initial contact and spread the liquid to 
other parts of the ventilation layer 32, and then substantially completely 
release such liquids into the layer or layers comprising the absorbent 
body 24. 
The different embodiments of the present invention, as representatively 
illustrated in FIGS. 1-6, advantageously provide improved absorbent 
articles which exhibit substantially reduced levels of hydration of the 
wearer's skin when in use compared to conventional absorbent articles. The 
reduced levels of skin hydration promote drier, more comfortable skin and 
render the skin less susceptible to the growth of microorganisms. Thus, 
wearer's of absorbent articles made according to the present invention 
have reduced skin hydration which can lead to a reduction in the incidence 
of skin irritation and rash. 
TEST PROCEDURES 
Hydrostatic Pressure Test 
The Hydrostatic Pressure Test is a measure of the liquid barrier properties 
of a material. In general, the Hydrostatic Pressure Test determines the 
height of water (in centimeters) in a column which the material will 
support before a predetermined amount of water passes through. A material 
with a higher hydrohead value indicates it is a greater barrier to liquid 
penetration than a material having a lower hydrohead value. The 
Hydrostatic Pressure Test is performed according to Method 5514--Federal 
Test Methods Standard No. 191A. 
Frazier Porosity Test 
The Frazier Porosity values referred to in the present specification can be 
determined employing a Frazier Air Permeability Tester (Frazier Precision 
Instrument Co., Gaithersburg, Md.) and Method 5450, Federal Test Methods 
Standard No. 191A. For the purposes of the present invention, the test is 
conducted with a sample which measures 8 inches.times.8 inches. 
Water Vapor Transmission Test 
A suitable technique for determining the WVTR (water vapor transmission 
rate) value of a material is as follows. For the purposes of the present 
invention, 3-inch diameter (76 millimeter) circular samples are cut from 
the test material and from a control material, Celguard.RTM. 2500 (Hoechst 
Celanese Corporation). Two or three samples are prepared for each 
material. Test cups used for testing are cast aluminum, flanged, 2 inches 
deep and come with a mechanical seal and neoprene gasket. The cups are 
distributed by Thwing-Albert Instrument Company, Philadelphia, Pa., under 
the designation Vapometer cup #681. One hundred milliliters of distilled 
water are poured into each Vapometer cup, and each of the individual 
samples of the test materials and control material are placed across the 
open top area of an individual cup. Screw-on flanges are tightened to form 
a seal along the edges of the cups leaving the associated test material or 
control material exposed to the ambient atmosphere over a 62 millimeter 
diameter circular area (an open, exposed area of about 30 cm.sup.2). The 
cups are then weighed, placed on a tray, and set in a forced air oven set 
at 100.degree. F. (38.degree. C.). The oven is a constant temperature oven 
with external air circulating through it to prevent water vapor 
accumulation inside. A suitable forced air oven is, for example, a Blue M 
Power-O-Matic 60 oven distributed by Blue M Electric Co. of Blue Island, 
Ill. After 24 hours, the cups are removed from the oven and weighed. The 
preliminary, test WVTR value is calculated as follows: 
##EQU1## 
The relative humidity within the oven is not specifically controlled. Under 
predetermined set conditions of 100.degree. F. and ambient relative 
humidity, the WVTR for Celguard 2500 has been determined to be 5000 
g/m.sup.2 /24 hours. Accordingly, Celguard 2500 is run as a control sample 
with each test. Celguard 2500 is a 0.0025 cm thick film composed of a 
microporous polypropylene. 
Skin Hydration Test 
Skin hydration values are determined by measuring total evaporative water 
loss (EWL) and can be determined by employing the following test 
procedure. 
The test is conducted on partially toilet trained infants who have no 
lotions or ointments on the skin and have not been bathed within 2 hours 
prior to the test. Each infant tests one diaper during each test session. 
The test diapers include a test code and a control code. The test diapers 
(test code and control code) are randomized. 
Each test diaper is weighed before and after use to verify the volume of 
liquid added into the diaper. A felt tip pen is employed to mark an "X" at 
the target zone inside the diaper, with the "X" positioned 6.5 inches 
below the top front edge of the diaper and centered side-to-side. The EWL 
measurements are taken with an evaporimeter, such as an Evaporimeter EP1 
instrument distributed by Servomed AB, Stockholm, Sweden. Each test 
measurement is taken over a period of two minutes with EWL values taken 
once per second (a total of 120 EWL values). The digital output from the 
Evaporimeter EP1 instrument gives the rate of evaporative water loss (EWL) 
in g/m.sup.2 /hr. Skin hydration values (SHV) are in units of total amount 
of water loss per unit area measured during the two-minute sampling period 
and are calculated as follows. 
##EQU2## 
A preliminary skin hydration value measurement is taken after a 15-minute 
"dryout" period when the infant wears only a long T-shirt or dress and is 
in the supine position. The measurement is taken on the infant's lower 
abdomen, in a region corresponding to the target zone of the diaper, using 
the evaporimeter for the purpose of establishing the initial skin 
hydration value of the infant's skin at the diaper target zone. If the 
preliminary SHV is less than 10 g/m.sup.2 /hour, a diaper is then placed 
on the infant. If the preliminary SHV is greater than 10 g/m.sup.2 /hour, 
the "dryout" period is extended until a reading below 10 g/m.sup.2 /hour 
is obtained. Prior to securing the diaper on the infant, a tube is 
positioned to direct a flow of liquid to hit the premarked target zone. 
Once the diaper is secured, 210 milliliters of adjusted 0.9 weight percent 
aqueous saline is added in three insults of 70 milliliters each at a rate 
of 15 milliliters/second with a 45 second delay between insults. 
The infant wears the diaper for 60 minutes after which the diaper is 
removed and a test measurement of skin hydration is taken on the lower 
abdomen corresponding to the target zone mark of the diaper. The 
measurement is taken over a 2-minute period. The used diaper is then 
weighed. Relative humidity and temperature measurements can be taken 
within the diaper prior to the skin hydration measurements being taken. 
The test procedure is then repeated the next day for each infant using the 
diaper type (test or control) which the infant has not yet worn. The 
control diaper provides a standardized basis for comparing the performance 
of the diaper configuration being tested and evaluated. The control 
diapers used in the tests performed in connection with the Examples were 
commercially available HUGGIES.RTM. Supreme diapers sold by Kimberly-Clark 
Corporation. 
Data is discarded for any infants which have added to the loading of saline 
solution. The value reported for the mean net SHV (grams/m.sup.2 in one 
hour) is the arithmetic mean for all infants of the post-wear skin 
hydration value, taken at the lower abdomen (target zone mark), minus the 
skin hydration value measured at the lower abdomen prior to placing the 
diaper on the infant (after "dryout" period). A separate mean net SHV is 
determined for the test code diapers and the control code diapers. 
The net skin hydration value is determined as follows: 
EQU Net SHV.sub.i =Y-Z 
Where: 
Y=skin hydration value measured at target zone mark of an individual infant 
Z=baseline skin hydration value measured on the lower abdomen after 
"dryout" period prior to placing diaper on the infant 
SHV.sub.i =skin hydration value for individual infant 
Then, 
##EQU3## 
Where: N=number of infants in study 
The percent reduction in skin hydration is determined as follows: 
##EQU4## 
Where: C=Net SHV.sub.i for control diaper code 
D=Net SHV.sub.i for test diaper code 
N=number of infants in study 
Tracer Gas Test 
The Tracer Gas Test is a measure of the rate of air exchange in garments 
such as absorbent articles and is a steady flow/steady state test 
described generally in TAPPI JOURNAL., Volume 80, No. 9, September 1997. 
In general, the air exchange rate values are calculated from the measured 
mass exchange within the garment. The test involves injecting a tracer gas 
at a constant rate inside the article next to the outer surface of the 
torso of a mannequin while the article is secured about the mannequin. 
Simultaneously, the concentration of the tracer gas in the air space 
between the article and the mannequin is measured by withdrawing a sample 
at the same constant rate as the injection. The air exchange rate is then 
be determined based on mass balances of the tracer gas and the air within 
the space in question. The Tracer Gas Test is completed as follows: 
Equipment 
1. Mannequin--The test is conducted with Step 3 or Step 4 sized diapers 
designed for infants weighing from about 16 to about 28 pounds and from 
about 22 to about 37 pounds, respectively. The diapers are placed on 
mannequins which have the following dimensions: 
______________________________________ 
Step 3 
height (waist to knees) 
26 centimeters 
circumference at waist 
42 centimeters 
circumference at hips 
44 centimeters 
thigh circumference 
22 centimeters 
Step 4 
height (waist to knees) 
28 centimeters 
circumference at waist 
48 centimeters 
circumference at hips 
51 centimeters 
thigh circumference 
27 centimeters 
______________________________________ 
2. A test area which is environmentally controlled to 20.degree. C. and 50% 
relative humidity. 
3. CO.sub.2 Analyzer--An infrared CO.sub.2 Analyzer auch as Model 17515A 
commercially available from Vacu-Med Vacumetrics, 4483 McGrath Street 
#102, Ventura, Calif. 
4. Rotameters--Rotameters to maintain gas flow rates such as Matheson 
Rotameter Model TS-35 commercially available from Specialty Gases 
Southeast Inc., 3496 Peachtree Parkway, Suwanee, Ga. 
5. Gas Cylinders--Two gas cylinders of calibrated medical grade gas at a 
pressure of 4 kPa from Specialty Gases Southeast Inc., 3496 Peachtree 
Parkway, Suwanee, Ga. The tracer gas includes 5% CO.sub.2 and air and the 
calibration gas is 100% air. 
Procedure 
1. Turn the CO.sub.2 analyzer on. After it has been on for 30 minutes, 
calibrate the analyzer with the calibration gas and adjust the flow 
control to achieve a flow rate of 150 cubic centimeters per minute through 
the analyzer. 
2. Place the diaper to be tested on the mannequin. 
3. Turn on the CO.sub.2 tracer gas flow. The flow rate of the injected 
tracer gas into the space between the diaper and the mannequin must be 
equal to the sample flow rate through the CO.sub.2 analyzer (150 cc/min.). 
4. Measure and record the concentration (C) of the tracer gas (CO.sub.2) in 
the air space between the diaper and the mannequin every 10 seconds for 20 
minutes. The data over the last 10 minutes are averaged and used to 
calculate the air exchange rate as follows: 
EQU Air Exchange Rate=150cc/min*[(C.sub.T -C)/(C-C.sub.O)] 
wherein, 
C.sub.T =concentration of the tracer gas (5%) 
C=concentration of the tracer gas in the space being measured 
C.sub.O =concentration of the tracer gas in the chamber environment (0.04%) 
The Dry Air Exchange Rate is the air exchange rate as determined according 
to the above procedure before the diaper has been subjected to any 
insults. The Wet Air Exchange Rate is the air exchange rate determined 
according to the above procedure except that once the diaper is secured to 
the mannequin, 180 milliliters (Step 3) or 210 milliliters (Step 4) of 
adjusted 0.9 weight percent aqueous saline is added in three insults of 60 
or 70 milliliters each at a rate of 15 milliliters/second with a 45 second 
delay between insults. The Wet Air Exchange Rate/Dry Air Exchange Rate 
ratio is determined by dividing the Wet Air Exchange Rate by the Dry Air 
Exchange Rate for the same sample. 
C. albicans Growth Test 
The C. albicans Growth Test is a measure of the effect of absorbent 
garments, such as disposable diapers, on the growth of pathogenic 
microorganisms and, in particular, Candida albicans. In general, the C. 
albicans Growth Test involves inoculating delineated sites of each volar 
forearm of test subjects with a suspension of C. albicans cells, covering 
the sites with full thickness patch from the absorbent garment, and 
determining the level of growth after a 24 hour period. 
A full thickness test sample patch having a length of 7 centimeters and a 
width of 7 centimeters is cut from the target zone of each product to be 
tested. The target zone is generally that portion of the product intended 
to receive urine discharge from the wearer and typically includes portions 
of the intermediate and front waist sections of the product somewhat 
forward of the lateral centerline of the product. In a typical diaper 
configuration, the full thickness test sample patch includes the topsheet, 
absorbent body, backsheet and any intervening layers. Approximately 15 
milliliters of a 0.9 weight percent saline solution is added to the test 
sample patch and allowed to soak in for 2 minutes before the samples are 
placed on the forearms of the test subjects. A test site area of 6.15 
square centimeters is marked on the each of the test subject's volar 
forearms. Approximately 0.01 milliliters of a 0.9 weight percent saline 
solution containing a suspension of C. albicans cells is delivered to the 
test site with micropipettes and the suspension is then spread uniformly 
across the test site. After air drying, the test cite is covered with the 
test sample patch which is secured in position using adhesive tape 
completely surrounding the sample. 
After 24 hours, the test sample patches are removed and a quantitative 
culture is obtained from the test site using the detergent scrub method 
set forth in "A New Method For Quantitative Investigation of Cutaneous 
Bacteria", P. Williamson and A. M. Klingman, Journal of Investigative 
Dermatology, 45:498-503, 1965, the disclosure of which is hereby 
incorporated by reference. Briefly, a sterile glass cylinder encompassing 
an area of 6.15 square centimeters is centered over the test site and held 
firmly to the skin. One milliliter of 0.1 weight percent Triton-x-100 in 
0.075M phosphate buffer having a pH of 7.9 is pipetted into the glass 
cylinder and the area scrubbed for one minute using a sterile Teflon rod. 
The fluid is aspirated with a sterile pipette and a second milliliter of 
0.1 weight percent Triton-x-100 in 0.075M phosphate buffer having a pH of 
7.9 is added to the glass cylinder. The scrub step is repeated and the two 
washes are pooled. Each pooled sample is diluted in ten-fold steps with of 
0.05 weight percent Triton-x-100 in 0.0375M phosphate buffer having a pH 
of 7.9. A 0.01 milliliter aliquot of each dilution is inoculated onto 
Sabourands agar containing antibiotics. Duplicate cultures are prepared 
and incubated at room temperature for 48 hours. 
After incubation, the number of colony forming units are counted using 
standard microbiological methods. The C. albicans growth under a patch of 
the test sample can then be compared to the C. albicans growth under a 
control patch from a conventional absorbent article having a nonbreathable 
outer cover, i.e. an outer cover having a WVTR of less than 100 grams per 
square meter per 24 hours, such as the diaper described below in 
connection with Comparative Example 4. 
The following examples are presented to provide a more detailed 
understanding of the invention. The specific materials and parameters are 
exemplary and are not intended to specifically limit the scope of the 
invention. 
EXAMPLES 
Example 1 
Disposable diapers having the same general construction as the HUGGIES.RTM. 
Supreme Step 3 diapers described in connection with Comparative Example 2 
below were hand made and tested. The diapers were substantially the same 
as the Supreme diapers except that the backsheet, absorbent core, surge 
layer and elasticized legbands of the diapers were replaced or modified 
and a ventilation layer was added between the backsheet and the absorbent 
core. 
In the tested diapers, the backsheet included a microporous film/nonwoven 
laminate material comprising a spunbond nonwoven material laminated to a 
microporous film. The spunbond nonwoven comprised filaments of about 1.8 
denier extruded from a copolymer of ethylene with about 3.5 weight percent 
propylene and defined a basis weight of from about 20 grams per square 
meter. The film comprised a cast coextruded film having calcium carbonate 
particles therein and defined a basis weight of about 58 grams per square 
meter prior to stretching. The film was preheated, stretched and annealed 
to form the micropores and then laminated to the spunbond nonwoven 
material. The resulting microporous film/nonwoven laminate based material 
had a basis weight of 45 grams per square meter and a water vapor 
transmission rate of about 4000 grams per square meter per 24 hours. 
Examples of such film/nonwoven laminate materials are described in more 
detail in U.S. patent application Ser. No. 08/882,712 filed Jun. 25, 1997, 
in the name of McCormack et al. and entitled "LOW GAUGE FILMS AND 
FILM/NONWOVEN LAMINATES", the disclosure of which has been incorporated by 
reference. 
The absorbent core in the tested diapers was a dual layer absorbent having 
the general configuration set forth in FIGS. 5 and 6 except that there 
were no holes or apertures through either layer of the absorbent. The 
absorbent core included an upper layer and a lower layer with the upper 
layer extending from the front edge of the absorbent core to a location 
about two thirds of the total length of the absorbent core. The absorbent 
core included from about 10 to about 11 grams of wood pulp fibers and from 
about 10 to about 11 grams of superabsorbent material and, accordingly, 
included about 50 weight percent wood pulp fibers and about 50 weight 
percent superabsorbent material. The lower layer had a basis weight of 
about 230 grams per square meter and the upper layer had a basis weight of 
about 560 grams per square meter to provide a total basis weight of about 
790 grams per square meter in the front section of the core and a basis 
weight of about 230 grams per square meter in the back section of the 
core. The absorbent core further defined a width in the crotch section of 
about 6.35 centimeters. 
The surge layer was located between the absorbent core and the topsheet and 
was the same material as the surge layer in the Supreme diapers described 
in Comparative Example 2 except that it was modified to be coextensive 
with the absorbent core. The diapers also included a ventilation layer 
between the absorbent core and the backsheet of the diaper. The 
ventilation layer was made of the same material as the surge layer and was 
also coextensive with the absorbent core. The diapers 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 (6) strands of 
elastomeric material laminated to a breathable, nonwoven fabric layer. The 
elastic strands were composed of LYCRA.RTM. elastomer aligned along the 
longitudinal length of the diaper to elasticize and gather the diaper 
legbands. 
Four samples of the diapers were subjected to the Tracer Gas Test set forth 
above. The results are set forth in Table 1 below. 
Example 2 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 1 were hand made and tested. The 
diapers were substantially the same as the Example 1 diapers except that 
the absorbent body was modified to include a plurality of holes 
therethrough in the region where the upper layer overlaid the lower layer 
as illustrated in FIGS. 5 and 6. The holes had a diameter of 1.27 
centimeters to provide an open area of about 12 percent based on a total 
surface area of the absorbent body. Four samples of the diapers were 
subjected to the Tracer Gas Test set forth above. The results are set 
forth in Table 1 below. 
Example 3 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested. The 
diapers were substantially the same as the Example 2 diapers except that 
the ventilation layer between the absorbent body and the backsheet was 
removed. Four samples of the diapers were subjected to the Tracer Gas Test 
set forth above. The results are set forth in Table 1 below. 
Example 4 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested. The 
diapers were substantially the same as the Example 2 diapers except that 
the holes in the absorbent body had a diameter of 2.54 centimeters which 
also defined an open are of about 12 percent of the total surface are of 
the absorbent body. Four samples of the diapers were subjected to the 
Tracer Gas Test set forth above. The results are set forth in Table 1 
below. 
Example 5 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested. The 
diapers were substantially the same as the Example 2 diapers except that 
the layered absorbent body was replaced with a non-layered absorbent body 
which included about 62 weight percent wood pulp fibers and about 38 
weight percent superabsorbent and defined a basis weight in the front 
section of about 750 to about 850 grams per square meter and a basis 
weight in the back section of about 375 to about 425 grams per square 
meter. Four samples of the diapers were subjected to the Tracer Gas Test 
set forth above. The results are set forth in Table 1 below. 
Example 6 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested. The 
diapers were substantially the same as the Example 2 diapers except that 
the dual layered absorbent core was replaced with a laminate which 
included about 80 weight percent superabsorbent material commercially 
available from Stockhausen under the trade designation FAVOR SXM 880 
overwrapped by a tissue layer of cellulosic fibers having a basis weight 
of about 26 grams per square meter. The absorbent body also included 
apertures therethrough having a diameter of 1.27 centimeters to provide an 
open area of about 12 percent of the total surface area of the absorbent 
body. Four samples of the diapers were subjected to the Tracer Gas Test 
set forth above. The results are set forth in Table 1 below. 
Example 7 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested. The 
diapers were substantially the same as the Example 2 diapers except that 
the absorbent body was replaced with a laminate which included about 80 
weight percent superabsorbent material commercially available from 
Stockhausen under the trade designation FAVOR SXM 880 overwrapped by a 
tissue layer of cellulosic fibers having a basis weight of about 26 grams 
per square meter. The laminate was provided in four segments as 
representatively illustrated in FIGS. 3 and 4 which resulted in an open 
for the absorbent body of about 40 percent of a total surface area of the 
absorbent body. Four samples of the diapers were subjected to the Tracer 
Gas Test set forth above. The results are set forth in Table 1 below. 
Example 8 
Disposable diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested. The 
diapers were substantially the same as the Example 2 diapers except that 
the backsheet was modified to define a water vapor transmission rate of 
about 1870 grams per square meter per 24 hours. Four samples of the 
diapers were subjected to the Tracer Gas Test set forth above. The results 
are set forth in Table 1 below. 
Comparative Example 1 
Disposable diapers having the same general construction as the Supreme Step 
3 diapers as described in connection with Example 2 were hand made and 
tested. The diapers were substantially the same as the Example 2 diapers 
except that the backsheet was replaced with a 1 mil thick polyethylene 
film material having a water vapor transmission rate of less than 100 
grams per square meter per hour. Four samples of the diapers were 
subjected to the Tracer Gas Test set forth above. The results are set 
forth in Table 1 below. 
Comparative Example 2 
Disposable diapers having the same general construction as those diapers 
commercially available from Kimberly-Clark Corporation under the trade 
designation HUGGIES.RTM. Supreme Step 3 were tested. 
In essence, the Supreme diapers comprised an absorbent core consisting of a 
mixture of wood pulp fibers and superabsorbent material surrounded by a 
two piece cellulosic wrap sheet having a basis weight of about 16-21 grams 
per square meter. The absorbent core included from about 12.5 to about 
13.5 grams of airlaid wood pulp fibers and from about 7.0 to about 8.5 
grams of superabsorbent material. The superabsorbent material was 
purchased from Stockhausen under the trade designation FAVOR SXM 880. The 
superabsorbent material was homogeneously mixed with the pulp fibers to 
form a unitary layer having a density within the range of 0.25 to 0.35 
grams per cubic centimeter. The homogeneous mixture of the superabsorbent 
material and the wood pulp fibers was zoned along the machine direction to 
provide a basis weight of from about 600 to about 700 grams per square 
meter in the front section of the absorbent core and a basis weight of 
from about 300 to about 350 grams per square meter in the back section of 
the absorbent core. 
The Supreme diapers further included a composite backsheet comprising a 
vapor-permeable barrier layer adhesively laminated to a 
spunbond/meltblown/spunbond laminate material (hereinafter "SMS"). The SMS 
material had a basis weight of about 27 grams per square meter. The 
vapor-permeable barrier layer consisted of a polyolefin film which had a 
thickness of about 0.7 mil. and a basis weight of about 19.5 grams per 
square meter. The polyolefin film material was commercially available from 
Exxon Chemical Patents Incorporated, under the tradename EXXAIRE. The 
vapor-permeable barrier layer was adhered to the SMS laminate and 
positioned between the absorbent core and the SMS laminate material of the 
backsheet. The backsheet had a water vapor transmission rate of about 1500 
grams per square meter per 24 hours. The absorbent core was sandwiched 
between the backsheet and a topsheet composed of a spunbond web of 
polypropylene fibers having a basis weight of about 17 grams per square 
meter. A surge management layer composed of a bonded carded web was 
located between the topsheet and the absorbent core. The surge layer 
included bicomponent fibers and defined an overall basis weight of about 
83 grams per square meter. The surge layer was a homogeneous blend 
composed of about 60 weight percent polyethylene/polyester (PE/PET), 
sheath-core bicomponent fibers which had a fiber denier of about 3 d and 
about 40 weight percent single component polyester fibers which had a 
fiber denier of about 6 d and which have fiber lengths of from about 3.8 
to about 5.08 centimeters. The surge layer further defined a width of 
about 10.2 centimeters and a length of about 16.5 centimeters. The front 
edge of the surge layer was located 5.1 centimeters from the front edge of 
the absorbent core. 
The Supreme diapers further included a single component elasticized 
waistband and waist flap assembly at each longitudinal end of the diaper. 
The assembly had multiple strands of elastomeric material sandwiched and 
laminated between a polymer film layer and a nonwoven fabric layer. The 
polymer film was a 0.00075 inch thick film composed of a blend of a linear 
low density polyethylene and an ultra low density polyethylene. The 
nonwoven fabric layer was composed of a 20 grams per square meter web of 
polypropylene spunbond. The elastic strands were composed of about 8-16 
strands of LYCRA.RTM. elastomer aligned along the cross-direction of the 
diaper to elasticize and gather the diaper waistbands and the internal 
waist flaps. The Supreme diapers also included length-wise containment 
flaps which extend the full length of the diaper and elasticized leg bands 
along each longitudinal side edge of the diaper. The elastic strands in 
the leg band and containment flaps were composed of LYCRA.RTM. elastomer 
aligned along the longitudinal length of the diaper to elasticize and 
gather the diaper legbands and the containment flaps. 
Four samples of the diapers were subjected to the Tracer Gas Test set forth 
above. The results are set forth in Table 1 below. 
TABLE 1 
______________________________________ 
Mean Dry Air 
Mean Wet Air 
Exc. Rate 
Exc. Rate Wet/Dry 
(cm.sup.3 /min.) 
(cm.sup.3 /min.) 
Ratio 
______________________________________ 
Example 1 822 224 0.27 
Example 2 794 310 0.39 
Example 3 679 220 0.32 
Example 4 1050 360 0.34 
Example 5 758 190 0.25 
Example 6 724 240 0.33 
Example 7 677 153 0.23 
Example 8 495 316 0.63 
Comparative Ex. 1 
51 110 2.16 
Comparative Ex. 2 
513 171 0.33 
______________________________________ 
The test results from Examples 1-8 and Comparative Examples 1 and 2 
indicate that diapers made according to the present invention generally 
have improved levels of air exchange both when dry and when wet when 
compared to conventional diapers. 
Example 9 
Four samples of diapers having the same general construction as the diapers 
described in connection with Example 2 were hand made and tested according 
to the Skin Hydration Test set forth above. The diapers were substantially 
the same as the Example 2 diapers except that the diapers were similar in 
size to commercially available Step 4 size diapers, the absorbent body was 
a single layer having the same thickness throughout, and the apertures had 
a diameter of 2.54 centimeters. The diapers defined an average Skin 
Hydration Value of 8.1 grams per square meter per hour. The results are 
also set forth in Table 2 below. 
Example 10 
Four samples of diapers having the same general construction as the diapers 
described in connection with Example 6 were hand made and tested according 
to the Skin Hydration Test set forth above. The diapers were substantially 
the same as the Example 6 diapers except that the diapers were similar in 
size to commercially available Step 4 size diapers, the absorbent body 
defined a basis weight of about 560 grams per square meter and the 
apertures had a diameter of 2.54 centimeters. The diapers defined an 
average Skin Hydration Value of 2.8 grams per square meter per hour. The 
results are also set forth in Table 2 below. 
Example 11 
Four samples of diapers having the same general construction as the diapers 
described in connection with Example 7 were hand made and tested according 
to the Skin Hydration Test set forth above. The diapers were substantially 
the same as the Example 7 diapers except that the diapers were similar in 
size to commercially available Step 4 size diapers. The diapers defined an 
average Skin Hydration Value of 1.6 grams per square meter per hour. The 
results are also set forth in Table 2 below. 
Comparative Example 3 
Disposable diapers having the same general construction as those diapers 
commercially available from Kimberly-Clark Corporation under the trade 
designation HUGGIES.RTM. Supreme Step 4 were tested. In essence, the Step 
4 sized Supreme diapers were similar to the Step 3 sized Supreme diapers 
described above in connection with Comparative Example 2 except that the 
size of the materials was greater. 
Four samples of the diapers were subjected to the Skin Hydration Test set 
forth above. The diapers defined an average Skin Hydration Value of 19.3 
grams per square meter per hour. The results are also set forth in Table 2 
below. 
TABLE 2 
______________________________________ 
Skin Hydration Value 
(g/m.sup.2 /hr) 
______________________________________ 
Example 9 8.1 
Example 10 2.8 
Example 11 1.6 
Comparative Ex. 3 
19.3 
______________________________________ 
The test results from Examples 9-11 and Comparative Example 3 indicate that 
diapers made according to the teachings of the present invention exhibit 
significantly improved Skin Hydration Values when compared to conventional 
diapers. Specifically, diapers made according to the present invention 
exhibited a 58 to 92 percent reduction in the Skin Hydration Value. While 
some reduction in the Skin Hydration Value was anticipated due to the 
increased amount of air exchange within the diapers, the magnitude of the 
reduction was unexpected. 
Example 12 
Samples of diapers having the same general construction as the diapers 
described in connection with Comparative Example 2 were hand made and 
tested. The diapers were substantially the same as the Comparative Example 
2 diapers except that the backsheet was modified to define a water vapor 
transmission rate of about 3000 grams per square meter per 24 hours. The 
diapers were subjected to the C. albicans Growth Test set forth above. The 
samples of Example 13 and Comparative Example 4 (control) were tested on 
the volar forearms of each of seven test subjects. The sample diapers 
according to this example defined a mean C. albicans growth of 1.96 log of 
C. albicans colony forming units. Accordingly, compared to the mean C. 
albicans growth of the control (Comparative Example 4), the diapers 
according to this example defined a reduction in the C. albicans growth 
value of 26 percent. 
Example 13 
Samples of diapers having the same general construction as the diapers 
described in connection with Example 2 except that the backsheet defines a 
water vapor transmission rate of about 5000 grams per square meter per 24 
hours are made. The diapers are subjected to the C. albicans Growth Test 
set forth above. The samples of Example 14 and Comparative Example 4 
(control) are tested on the volar forearms of each of seven test subjects. 
It is anticipated that the sample diapers according to this example would 
define a mean C. albicans growth of more likely less than 1.75 and likely 
less than 1.50 log of C. albicans colony forming units. Accordingly, 
compared to the mean C. albicans growth of the control (Comparative 
Example 4), it is anticipated that the diapers according to this example 
will define a reduction in the C. albicans growth value of more likely 
about 34 percent and likely about 43 percent. 
Comparative Example 4 
Samples of diapers having the same general construction as the diapers 
described in connection with Comparative Example 2 were hand made and 
tested. The diapers were substantially the same as the Comparative Example 
2 diapers except the backsheet was replaced with a 1.0 mil thick 
polyethylene film material having a water vapor transmission rate of less 
than 100 grams per square meter per 24 hours. The diapers were subjected 
to the C. albicans Growth Test set forth above on the volar forearms of 
each of seven test subjects. The sample diapers according to this example 
defined a mean C. albicans growth of 2.65 log of C. albicans colony 
forming units. 
The test results from Example 12 and the expected results from Example 13 
show that diapers made according to the present invention exhibit a 
reduced growth and incidence of microbial infection when compared to 
conventional absorbent diapers and the test results from Comparative 
Example 4. It is clear that such reduced microbial growth is achieved by 
reducing the occlusion of the skin by increasing the breathability of the 
diaper both when dry and when wet. 
Having thus described the invention in rather full detail, it will be 
readily apparent to a person of ordinary skill that various changes and 
modifications can be made without departing from the spirit of the 
invention. All of such changes and modifications are contemplated as being 
within the scope of the present invention as defined by the subjoined 
claims.