An absorbent article, such as a pantiliner, has incorporated therein
an unactivated bentonite clay as an odor control material for decreasing
odors associated with bodily fluids.
What is claimed is:
1. An absorbent article having incorporated therein an odour control
material for decreasing odours associated with bodily fluids, wherein
the odour control material consists essentially of an unactivated
the odour control material is layered on an absorbent core; and
the absorbent article is selected from the group consisting of
sanitary napkins, pantiliners, disposable diapers, incontinence
pads, and tampons.
2. An absorbent article according to claim 1 wherein the bentonite
clay is selected from the group consisting of calcium bentonite
or sodium bentonite.
3. An absorbent article according to claim 1 wherein said absorbent
article also comprises an absorbent gelling material.
4. An absorbent article according to claim 1 wherein said absorbent
article is a pantiliner.
5. An absorbent article according to claim 4 wherein said odour
control material is used at a level of between about 0.25 and about
2.0 g of bentonite clay per article.
6. An absorbent article according to claim 5 wherein said odour
control material is used at a level of between about 0.5 and about
1.5 g of bentonite clay per article.
7. An absorbent article having incorporated therein an odour control
material for decreasing odours associated with bodily fluids, said
absorbent article comprising:
a liquid pervious topsheet;
a backsheet joined to said topsheet; and
an absorbent core disposed between said topsheet and said backsheet
wherein said absorbent core comprises an odour control material,
said odour control material consisting essentially of an unactivated
bentonite clay and said odour control material is layered on said
said absorbent article being selected from the group consisting
of sanitary napkins, pantiliners, disposable diapers, incontinence
pads, and tampons.
8. An absorbent article according to claim 7 wherein said absorbent
article further comprises a secondary topsheet disposed between
said topsheet and said absorbent core.
9. An absorbent article according to claim 7 wherein said topsheet
comprises a formed thermoplastic film.
10. An absorbent article according to claim 8 wherein said topsheet
comprises a formed thermoplastic film and said secondary topsheet
comprises a bicomponent web.
11. An absorbent article according to claim 7 wherein said core
further comprises absorbent gelling material.
12. An absorbent article according to claim 7 wherein said backsheet
has a core surface and an opposed outer surface, an adhesive being
disposed on said outer surface.
This invention relates to an absorbent article for absorbing bodily
fluids comprising an odour control material.
Absorbent articles are designed to be worn by humans to absorb
bodily fluids, such as urine, menstrual fluid and perspiration,
etc. Examples of absorbent articles include sanitary napkins, pantiliners,
disposable diapers, incontinence pads, tampons and the like.
In use, the absorbent articles are known to acquire a variety of
compounds, for example volatile fatty acids (e.g. isovaleric acid),
ammonia, amines (e.g. triethylamine), sulphur containing compounds
(e.g. mercaptans, sulphides), alcohols, ketones and aldehydes (e.g.
furaldehyde) which release unpleasant odours. These compounds may
be present in the bodily fluid or may be produced by fermentation
once the bodily fluid is absorbed into the pad. In addition bodily
fluids can contain microorganisms that can also generate malodorous
byproducts. Unpleasant odours which emanate from absorbent pads
when in use may make the wearer feel self conscious.
An object of the present invention is to provide an absorbent article
providing odour control using a material which can be handled easily
in production of an absorbent article, and is not expensive.
It has been found that bentonite clays have odour control properties
when incorporated in absorbent articles.
The present invention provides an absorbent article having incorporated
therein an odour control material for decreasing odours associated
with bodily fluids, the odour control material comprising at least
50% by weight, preferably at least 80% by weight, of a bentonite
According to one embodiment the absorbent article includes a bentonite
clay as the only odour control material.
A number of odour control materials have previously been suggested
for use in absorbent articles which, although efficient at odour
control, are very expensive. Examples are carbon black and zeolites.
The advantage of bentonite clays is that, on the one hand, they
are effective as odour control materials and, on the other hand,
they are readily available and relatively cheap. Accordingly, relatively
large amounts of bentonite clay can be included in an absorbent
article without substantially increasing the cost. Thus, whilst
it may be necessary to use more bentonite as an odour control material
in an absorbent article than, for example, carbon black or zeolite,
the equivalent degree of odour control can be achieved more cheaply
by use of bentonite.
The fact that more bentonite is used than, for example, carbon
black or zeolite for an equivalent odour control effect is itself
an advantage. Thus the requirements for production equipment and
process control are less stringent, for bentonite than is the case
for carbon black or zeolite where small amounts of materials have
to be metered accurately into each product. In addition, as well
as being an odour control material, bentonite is also an absorbent
and, when incorporated into an absorbent article in the quantities
appropriate for odour control, it can also supplement the absorbent
capacity of the product. Finally, in contrast to carbon black or
zeolite, bentonite is a naturally occurring mineral and may thus
have better acceptability to consumers in the context of absorbent
products such as sanitary products.
Any suitable bentonite clay with odour control properties can be
used according to the invention. Examples include:
calcium bentonite, for example in granular form
Preferably, the bentonite clays of the present invention comprise
at least about 90% montmorillonite. More preferably, the clays comprise
at least about 95% montmorillonite.
It is particularly preferred to use such calcium or sodium bentonite
in the unactivated state. As is known in the art, clays may be activated
by either heat treatment or acid treatment. As used herein, a bentonite
clay is "unactivated" if it can be provided using such
relatively simple processing steps, as mining, drying to remove
at least some of the loosely held (not structural) water, grinding,
and sizing (e.g. agglomeration and/or screening) without an acid
treatment or heat treatment (beyond what may be necessary to dry
the clay). As noted above, a particular benefit of the unactivated
bentonite clays of the present invention is their low cost. One
contributor to this low cost is the clays of the present invention
do not require an activation process step to be effective as odor
absorbers. An exemplary unactivated calcium bentonite is the granular
calcium bentonite available from Laviosa Chimica Mineraria SpA as
DETERCAL G IF. Such unactivated calcium bentonites are mined, dried,
ground, and agglomerated prior to shipment. An exemplary unactivated
sodium bentonite is available from ABI, Inc. of Palatine, IL as
AP BASE CLAY. Such unactivated sodium bentonites are mined, dried
and sized prior to shipment.
The absorbent article according to the invention may be a sanitary
napkin, a pantiliner a disposable diaper, an incontinence pad, tampon
or the like. According to one aspect of the invention the absorbent
article is a pantiliner. According to another aspect of the invention
the absorbent article is a sanitary napkin.
The amount of bentonite clay which may be used in the absorbent
article as an odour control material can be readily determined by
the skilled person bearing in mind the size of the absorbent article
in question. For example, a suitable quantity of bentonite clay
which may be used in a pantiliner, is from about 0.25 to 2.0 g,
preferably the quantity is from about 0.5 to 1.5 g.
The absorbent article may be of conventional construction and may
include other conventional components such as antimicrobial agents
and ionic absorbents, for example absorbent gelling material (AGM).
The quantity of AGM which may be added may also readily be determined
by the skilled person for each absorbent article. For example about
0.05 to 0.7 g, preferably about 0.1 to 0.5 g, AGM may be appropriate
for adding to a pantiliner.
The bentonite clay as an odour control material may be incorporated
into the absorbent article by methods known in the art, for example
the clay may be layered on the core of the absorbent material or
mixed within the fibres of the absorbent core. The odour control
material is preferably incorporated between two layers of cellulose
tissue and, optionally, the material may be bonded between two cellulose
tissue layers with, for example, a hot melt adhesive or any suitable
bonding system. For example the odour control material may be incorporated
in a layered structure in accordance with WO 94/01069 or Italian
Patent Application TO 93A 001028.
The invention will now be illustrated with reference to the detailed
description and examples taken in conjunction with the accompanying
FIG. 1 shows a schematic cross section of a commercially available
pantiliner is namely the Always Comfort Pantiliner (Always is a
registered trade mark).
FIG. 2 shows a schematic cross section of the pantiliner of FIG.
1 with odour control material incorporated therein.
FIG. 3 shows a schematic cross section of a pantiliner having an
absorbent core comprising three cellulose tissue layers, an odour
control material being incorporated between the first and second
FIG. 4 shows a schematic cross section of a pantiliner having an
absorbent core comprising three cellulose tissue layers, an odour
control material being incorporated between the second and third
An absorbent article, namely a pantiliner, which is an exemplary
embodiment of an article according to the invention, is shown in
cross section in FIGS. 1 to 4.
The pantiliner may be of any shape known in the art, for example,
rectangular, hour glass, winged, etc. As shown in FIGS. 1 and 2
pantiliner 1 comprises a liquid pervious topsheet 2, a secondary
top sheet 3, an absorbent core 4 and a liquid impervious backsheet
5. It is not, however, intended that the pantiliner according to
the invention should be limited to embodiments comprising all such
elements or additional elements may also be included.
The topsheets 2 and 3 are liquid permeable and, when pantiliner
1 is in use, are in close proximity to the skin of the user. The
topsheets 2 and 3 are compliant, soft feeling and non-irritating
to the user's skin and can be made from any of the conventional
materials for this type of use. Non-limiting examples of suitable
materials that can be used as the topsheets 2 and 3 are woven and
nonwoven polyester, polypropylene, nylon and rayon and formed thermoplastic
Formed films are preferred for topsheet 2. Suitable formed films
are described in U.S. Pat. No. 4324246, U.S. Pat. No. 4324214, U.S.
Pat. No. 4341217 and U.S. Pat. No. 4463045. Secondary topsheet 3
is preferably a non-woven, more preferably an air through non-woven
with a basis weight of 21 g/m.sup.2, the non-woven being a bi-component
web comprising polyester and polyethylene fibres in a mixture such
as disclosed in WO 93/09744.
Formed films are preferred for topsheet 2 because they are pervious
to liquids and yet non-absorbent. Thus, the surface of the formed
film, which is in contact with the body, remains dry and is more
comfortable to the wearer. The topsheet may be constituted by a
covering structure for sanitary products such as described in EP-A-0
207 904. Preferably, the topsheet 2 is made of polyethylene perforated
film (24.5 g/m.sup.2).
The inner surface of secondary topsheet 3 may be secured in contacting
relation to absorbent core 4. This contacting relationship results
in liquid penetrating the topsheet 3 faster than if it were not
in contact with absorbent core 4. Topsheet 3 can be maintained in
contact with the absorbent core 4 by applying adhesive, preferably
in spaced limited areas. Examples of suitable adhesives used for
such purpose include the acrylic emulsion E-1833BT manufactured
by the Rohm & Haas Company, Philadelphia, Pa. and the acrylic
emulsion WB 3805 manufactured by H. B. Fuller Company of St. Paul,
Minn. The adhesives can be applied by any technique, for example,
the adhesive may be applied by spraying, by padding or by the use
of transfer rolls. The adhesive may be in the form of a uniform
continuous layer, a patterned layer of adhesive, or an array of
separate lines, spirals or spots of adhesive. The absorbent core
4 is preferably secured in contacting relation to secondary topsheet
Referring again to FIGS. 1 and 2, it can be seen that absorbent
core 4 is positioned between secondary topsheet 3 and backsheet
5. Absorbent core 4 provides the absorptive means for absorbing
the bodily fluid. Absorbent core 4 is generally compressible, conformable
and non-irritating to the user's skin. It can comprise any suitable
material for such purpose. Examples of such materials include multiple
plies of creped cellulose wadding, fluffed cellulose fibres, wood
pulp fibres, also known as airfelt, textile fibres, a blend of fibres,
a mass or batt of fibres, a web of polymeric fibres, a blend of
polyester and polypropylene fibres, layers of cellulose tissue or
layers of air laid tissue.
Preferably, the core comprises a mass or batt of fibres. While
many types of fibres may be used, a preferred material is a batt
of polyester fibres. More preferably the core comprises cellulose
tissue (63 g/m.sup.2) which forms three absorbent layers. FIG. 1
shows an absorbent core 4 formed by one layer of cellulose tissue
which has been folded as shown. FIG. 2 shows an absorbent core comprised
of two layers of air laid cellulose tissue 6 joined at their longitudinal
edges with adhesive 7.
Preferably, the bentonite clay as an odour control material is
incorporated into the absorbent core. It may, for example, be layered
on the absorbent core or mixed with the fibres of the core. More
preferably, the odour control material 8, 20 is layered in accordance
with the teaching of WO 94/01069 or Italian Patent Application TO
93A 001028 between two layers of air laid cellulose tissue and the
laminate is as shown in FIGS. 2 to 4 above. In particular, polyethylene
powder, as thermoplastic material, may be mixed with bentonite clay
as an odour control material and AGM and the mixture heated such
that the polyethylene melts and glues the laminate layers and components
together. Polyethylene powder is preferably also placed on the edges
of the laminate as shown as 7, 15 and 18 in the Figures to ensure
that edges of the laminate stick together and any loose odour control
material or AGM does not fall out of the laminate.
As shown in FIGS. 3 and 4, pantiliner 9 comprises a liquid pervious
topsheet 10, an absorbent core 11, a liquid impervious backsheet
12, adhesive 13 which fastens the topsheet 10 to the backsheet 12,
a layer of adhesive 21 which is secured to the backsheet 12 and
which is covered by removable release liner 22. The removable release
liner 22 and associated adhesive 21 may also be included in the
pantiliners of FIGS. 1 and 2. In FIG. 4 adhesive 23 in addition
fastens the absorbent core 11 to the topsheet 10. It is not, however,
intended that the pantiliner should be limited to embodiments comprising
all such elements or additional elements may also be included.
Topsheet 10 is liquid permeable and, when pantiliner 9 is in use,
is in close proximity to the skin of the user. The topsheet 10 is
as described for topsheet 2 in FIGS. 1 and 2. The inner surface
of topsheet 10 may be secured in contacting relation to absorbent
core 11 as described for the pantiliner of FIGS. 1 and 2. Preferably,
the topsheet 10 wraps around the core 11, as shown in FIGS. 3 and
4, and is fastened by means of an adhesive 13 to backsheet 12.
Referring again to FIGS. 3 and 4, it can be seen that absorbent
core 11 is positioned between topsheet 10 and backsheet 12. Absorbent
core 11 is as described for FIG. 2. FIG. 3 shows an absorbent core
comprised of two layers of air laid cellulose tissue 14 joined at
their longitudinal edges with adhesive 15 and having a layer of
cellulose tissue 16 therebeneath to form a three layered absorbent
core. FIG. 4 shows two layers of air laid tissue 17 joined at their
longitudinal edges with adhesive 18 and having a layer of cellulose
tissue 19 wrapped therearound to form the third layer of the absorbent
Referring to FIGS. 1 to 4, the pantiliner is provided with a backsheet
5, 12 which backsheet is impervious to liquids and, thus, prevents;
menstrual fluid which may be expressed from absorbent core 4, 11
from soiling the body or clothing of the user. Suitable materials
include woven and non-woven fabrics which have been treated to render
them liquid repellent. Breathable or vapour pervious, liquid resistant
materials, and those materials described in U.S. Pat. No. 3,881,489
and U.S. Pat. No. 3,989,867 can also be used. Preferred materials
are those materials that are fluid and vapour impervious, because
they provide additional fluid strikethrough protection. Especially
preferred materials include formed thermoplastic films. One especially
suitable material is a polyethylene film having a thickness of from
about 0.075 mils to about 1.25 mils, with a 1.0 mil thickness polyethylene
film being especially suitable. Preferably the backsheet 5, 12 is
polyethylene embossed film (24.4 g/m.sup.2).
The outer surface of backsheet 5, 12 may be coated with adhesive
21. Adhesive 21 provides a means for securing the pantiliner in
the crotch portion of a panty. Any adhesive or glue suitable for
such purpose can be used herein, with pressure sensitive adhesives
being preferred. Suitable adhesives are Century A-305IV manufactured
by the Century Adhesives Corporation and Instant Lok 34-2823 manufactured
by the National Starch Company. Also, before pantiliner 1 or 9 is
placed in use, the pressure sensitive adhesive 21 should be covered
with removable release liner 22 in order to keep adhesive 11 from
drying out or sticking to a surface other than the crotch portion
of the panty prior to use. Any suitable release liner can be used
for this purpose and such release liners are commercially available.
Non-limiting examples of suitable release liners are BL 30 MG-A
Silox EI/O and BL 30 MG-A Silox 4 P/O both of which are manufactured
by the Akrosil Corporation. Preferably the release liner is a silicon
paper having a thickness of about 45 .mu.m (43.5 g/m.sup.2). Other
means which are known in the art may be used to affix the pantiliner
in the crotch portion of a panty. FIGS. 3 and 4 show an embodiment
which comprises the adhesive 21 and removable release liner 22.
The backsheet 5, 12 is preferably secured to the absorbent core
4, 11 by securement means (not shown), such as those well known
in the art. Suitable securement means are the same means hereinbefore
disclosed with respect to securing the secondary top sheet 3 to
absorbent core 4.
The invention will now be illustrated with reference to the examples
wherein the article for absorbing bodily fluids is a pantiliner
or a sanitary napkin. It will, of course, be appreciated that other
absorbent articles may also have the odour control material incorporated
therein, the incorporation of the odour control material into the
pantiliner may be achieved by other known methods and the odour
control material may be any of those disclosed in the present specification.
Incorporation of the odour control material into a pantiliner.
The pantiliners used in the following examples were Always COMFORT
Pantiliners (Always is a Registered Trade Mark) as sold by the Procter
& Gamble Company. Each pantiliner was opened at one end. The
inner cellulose tissue sheet, which constitutes the absorbent core
of the product, was substituted with two layers of cellulose tissue
that incorporate the odour control material homogeneously dispersed
therein as shown in FIG. 2. The whole pantiliner structure was then
Samples were prepared by the method as described above, which samples
incorporate bentonite clay as odour control material (OCM) as described
Product 1 included DETERCAL G 1F (granular calcium bentonite available
from Lavisoa Chimica Mineraria, Livorno, Italy) in an amount of
Product 2 included AP BASE CLAY (sodium bentonite available from
ABI, Inc., Palatine, Ill., USA) in an amount of 0.75 g/pantiliner.
A commercially available Always (Always is a Registered Trade Mark)
pantiliner without modification was used as a reference.
Odour Control Test Protocol
Each test comprises four separate stages which may be summarised
a) Consignment of the products.
b) Product return and preparation of the test samples.
d) Statistical analysis of the Data.
Each stage is described in more detail below.
a) Women were chosen who were known to have an odour control problem.
Each of five women selected was given a sample of each product individually
packaged in an anonymous bag. Each product was worn for seven hours.
b) The used product was placed into an aluminum tray, approximately
1 cm deep, covered with a perforated aluminum sheet, in order to
keep it out of view, and finally covered with another tray of the
same type, which was kept thereon in inverted position up to the
moment of the sniff-test.
c) The sniff-test was performed in a pre-ventilated room by five
graders. Each grader had been preselected for their sensitivity
to the unpleasant smells present in an absorbent article after use
and their ability to grade the unpleasantness of the odour in a
consistent manner. Every grader evaluated the odour of samples representing
each of the products using a pleasantness scale which ranges from
-10 (highest level of unpleasantness) to 5 (most pleasant). The
pleasantness values for each product were obtained as a mean of
5 observations (five graders, one sample for each product).
d) The results collected from the test were then analyzed by statistical
analysis software (SAS). The data was processed in order to show
statistically significant differences between the treated and untreated
products. This difference is shown in the table by means of a letter
in the "Sig. Diff."(significant difference) column; results
with the same letter are not significantly different. The standard
for a significant difference is that of the Student's two tailed
"t" test for comparison of data between two types of sample.
Values of p<0.05 are considered statistically significant.
The results are shown in the following table:
PRODUCT SCORE SIG. DIFF. Product 1 -1.9 A (0.75 g/sample Ca bentonite)
Reference -3.7 B Product 2 -1.6 A (0.75 g/sample Na bentonite) Reference
-2.4 B p <0.05
These results show that bentonite clay has a substantial odour
control effect with respect to the reference.
The disclosures of all patents, patent applications (and any patents
which issue thereon, as well as any corresponding published foreign
patent applications), and publications mentioned throughout this
description are hereby incorporated by reference herein. It is expressly
not admitted, however, that any of the documents incorporated by
reference herein teach or disclose the present invention.
While particular embodiments of the present invention have been
illustrated and described, it would be obvious to those skilled
in the art that various other changes and modifications can be made
without departing from the spirit and scope of the invention. It
is therefore intended to cover in the appended claims all such changes
and modifications that are within the scope of this invention.