U.S. patent number 3,815,601 [Application Number 05/358,773] was granted by the patent office on 1974-06-11 for catamenial aggregate absorbent body.
This patent grant is currently assigned to The Procter & Gamble Company. Invention is credited to Jean Edward Schaefer.
United States Patent |
3,815,601 |
Schaefer |
June 11, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
CATAMENIAL AGGREGATE ABSORBENT BODY
Abstract
A tampon wherein the absorbent body is an aggregate of separate
pieces of low modulus, resilient, absorbent foam. The aggregate is
held together by an encasing overwrap which is relatively loose
about the aggregate to permit some relative motion between adjacent
pieces of foam. The mesh of the overwrap is fine enough to totally
contain the absorbent pieces and thereby prevent surfaces of the
absorbent pieces from penetrating the overwrap and forming part of
the external surface of the tampon.
Inventors: |
Schaefer; Jean Edward
(Cincinnati, OH) |
Assignee: |
The Procter & Gamble
Company (Cincinnati, OH)
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Family
ID: |
26943767 |
Appl.
No.: |
05/358,773 |
Filed: |
May 9, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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254004 |
May 17, 1972 |
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Current U.S.
Class: |
604/15; 604/369;
604/376; 604/904; 604/385.18 |
Current CPC
Class: |
A61F
13/2051 (20130101); Y10S 604/904 (20130101) |
Current International
Class: |
A61F
13/20 (20060101); A61f 013/20 () |
Field of
Search: |
;128/263,270,285,290,287,296 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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606,627 |
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Dec 1934 |
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DD |
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718,042 |
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Jan 1932 |
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FR |
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805,662 |
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May 1951 |
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DT |
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1,121,770 |
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Jan 1962 |
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DT |
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Primary Examiner: Rosenbaum; Charles F.
Attorney, Agent or Firm: Braun; Frederick H. Gorman; John V.
Witte; Richard C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of copending
U.S. application Ser. No. 254,004, filed May 17, 1972 and now
abandoned.
Claims
What is claimed is:
1. An absorptive device, comprising: an aggregate of individual
pieces of absorbent foamlike material, said aggregate being encased
within a flexible fluid-permeable overwrap, said pieces being
wholly contained within the exterior portion of said overwrap such
that substantially none of the absorbent foamlike material
protrudes through the exterior portion of the overwrap whereby the
exterior surface of the tampon is formed by the overwrap, said
aggregate being flexible and resilient and having a dry aggregate
modulus of compression at 25 percent compression in the range of
about 0.004 psi to about 0.050 psi, whereby said aggregate is
maintained by said overwrap and said device is soft, highly
compressible, conformable to its surroundings, and resilient.
2. An absorptive device, comprising: an aggregate of individual
pieces of absorbent foamlike material, said aggregate being encased
within a flexible fluid-permeable overwrap, said aggregate being
flexible and resilient and having a dry aggregate modulus of
compression at 25 percent compression in the range of about 0.004
psi to about 0.050 psi, the volume packing factor of said device
being equal to or less than about 2.0 cubic inches of the absorbent
material per cubic inch available within the overwrap, whereby the
overwrap has low tensional forces therein and said device has an
amorphous character.
3. The device of claim 2 wherein said pieces are irregularly
shaped.
4. The device of claim 2 wherein said overwrap is essentially
tubular, each longitudinal end of the tubular overwrap is gathered
radially inwardly to form a closure, one longitudinal portion of
the overwrap is a reentrant portion and another longitudinal
portion of the overwrap is an exterior portion, said exterior
portion forms the outer surface of said device, and said reentrant
portion is reentrant upon the combination of said aggregate and
said exterior portion, whereby said device has a cavity
therewithin, said cavity extending substantially from one
longitudinal end of said device toward the opposite longitudinal
end and the interior surface of said cavity is formed by said
reentrant portion.
5. The device of claim 2 wherein an ancillary absorbent material is
distributed within said aggregate.
6. The device of claim 2 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
7. The device of claim 6 wherein
A. said overwrap is essentially tubular, each longitudinal end of
the tubular overwrap is gathered radially inwardly to form a
closure, one longitudinal portion of the overwrap is a reentrant
portion and another longitudinal portion of the overwrap is an
exterior portion, said exterior portion forms the outer surface of
said device, and said reentrant portion is reentrant upon the
combination of said aggregate and said exterior portion, whereby
said device has a cavity therewithin, said cavity extending
substantially from one longitudinal end of said device toward the
opposite longitudinal end and the interior surface of said cavity
is formed by said reentrant portion; and
B. an ancillary absorbent material is distributed within said
aggregate.
8. The device of claim 1 wherein said pieces are irregularly
shaped.
9. The device of claim 8 wherein said overwrap is essentially
tubular, each longitudinal end of the tubular overwrap is gathered
radially inwardly to form a closure, one longitudinal portion of
the overwrap is a reentrant portion and another longitudinal
portion of the overwrap is an exterior portion, said exterior 1
street. Therefore, Amber portion forms the outer surface of said
device, and said reentrant portion is reentrant upon the
combination of said aggregate and said exterior portion, whereby
said device has a cavity therewithin, said cavity extending
substantially from one longitudinal end of said device toward the
opposite longitudinal end and the interior surface of said cavity
is formed by said reentrant portion.
10. An absorptive device, comprising: an aggregate of individual
pieces of absorbent foamlike material, the pieces being irregularly
shaped, an ancillary absorbent material being distributed within
said aggregate, and said aggregate being encased within a flexible
fluid-permeable overwrap, said aggregate being flexible and
resilient and having a dry aggregate modulus of compression at 25
percent compression in the range of about 0.004 psi to about 0.050
psi.
11. The device of claim 1 wherein said overwrap is essentially
tubular, each longitudinal end of the tubular overwrap is gathered
radially inwardly to form a closure, one longitudinal portion of
the overwrap is a reentrant portion and another longitudinal
portion of the overwrap is an exterior portion, said exterior
portion forms the outer surface of said device, and said reentrant
portion is reentrant upon the combination of said aggregate and
said exterior portion, whereby said device has a cavity
therewithin, said cavity extending substantially from one
longitudinal end of said device toward the opposite longitudinal
end and the interior surface of said cavity is formed by said
reentrant portion.
12. An absorptive device, comprising: an aggregate of individual
pieces of absorbent foamlike material, an ancillary absorbent
material being distributed within said aggregate, and said
aggregate and ancillary absorbent material being encased within a
flexible fluid-permeable overwrap, said aggregate being flexible
and resilient and having a dry aggregate modulus of compression at
25 percent compression in the range of about 0.004 psi to about
0.050 psi, said overwrap being essentially tubular, each
longitudinal end of the tubular overwrap being gathered radially
inwardly to form a closure, one longitudinal portion of the
overwrap being a re-entrant portion and another longitudinal
portion of the overwrap being an exterior portion, said exterior
portion forming the outer surface of said device, and said
re-entrant portion being re-entrant upon the combination of said
aggregate and said exterior portion; whereby said aggregate is
maintained by said overwrap and said device is soft, highly
compressible, conformable to its surroundings, and has a cavity
therewithin, said cavity extending substantially from one
longitudinal end of said device toward the opposite longitudinal
end and the interior surface of said cavity being formed by said
re-entrant portion.
13. The device of claim 11 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
14. An absorptive device, comprising: an aggregate of individual
pieces of absorbent foamlike material, an ancillary absorbent
material being distributed within said aggregate, and said
aggregate and ancillary absorbent material being encased within a
flexible fluid-permeable overwrap, said aggregate being flexible
and resilient and having a dry aggregate modulus of compression at
25 percent compression in the range of about 0.004 psi to about
0.050 psi.
15. The device of claim 14 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
16. The device of claim 1 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
17. An absorptive device, comprising: an absorptive tampon, a
tubular inserter, and ejection means operatively associated with
said tampon and said inserter for releasing said tampon from said
inserter into a body cavity; said tampon being an aggregate of
individual pieces of absorbent foamlike material, said aggregate
being encased within a flexible fluid-premeable overwrap, said
pieces being wholly contained within the exterior portion of said
overwrap such that substantially none of the absorbent foam-like
material protrudes through the exterior portion of the overwrap
whereby the exterior surface of the tampon is formed by the
overwrap, said aggregate being flexible and resilient and having a
dry aggregate modulus of compression at 25 percent compression in
the range of about 0.004 to about 0.050 psi, said tampon being
resiliently compacted within said inserter, whereby said tampon is
easily ejectable, and fluffs out rapidly after in vivo ejection
from said inserter to fill the vaginal cross-section.
18. An absorptive device, comprising: an absorptive tampon, a
tubular inserter, and ejection means operatively associated with
said tampon and said inserter for releasing said tampon from said
inserter into a body cavity; said tampon being an aggregate of
individual pieces of absorbent foamlike material, said absorbent
material having a dry aggregate modulus of compression at 25
percent compression in the range of about 0.004 to about 0.050 psi,
and said aggregate being encased within a flexible fluid-permeable
overwrap, the volume packing factor of said tampon being less than
or equal to about 2.0 cubic inches of the absorbent material per
cubic inch available within the overwrap, said tampon being
resiliently compacted within said inserter, whereby the tampon is
easy to eject from the inserter.
19. The device of claim 18 wherein said pieces are irregularly
shaped.
20. The device of claim 19 wherein
A. said overwrap is essentially tubular, each longitudinal end of
the tubular overwrap is gathered radially inwardly to form a
closure, one longitudinal portion of the overwrap is a reentrant
portion and another longitudinal portion of the overwrap is an
exterior portion, said exterior portion forms the outer surface of
said device, and said reentrant portion is reentrant upon the
combination of said aggregate and said exterior portion, whereby
said device has a cavity therewithin, said cavity extending
substantially from one longitudinal end of said device toward the
opposite longitudinal end and the interior surface of said cavity
is formed by said reentrant portion;
As an an ancillary absorbent material is distributed within said
aggregate; and
C. the size of substantially all of said pieces is within the range
of from about 1/16 to about 1.0 inch.
21. The device of claim 18 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
22. The device of claim 18 wherein said overwrap is essentially
tubular, each longitudinal end of the tubular overwrap is gathered
radially inwardly to form a closure, one longitudinal portion of
the overwrap is a reentrant portion and another longitudinal
portion of the overwrap is an exterior portion, said exterior
portion forms the outer surface of said device, and said reentrant
portion is reentrant upon the combination of said aggregate and
said exterior portion, whereby said device has a cavity
therewithin, said cavity extending substantially from one
longitudinal end of said device toward the opposite longitudinal
end and the interior surface of said cavity is formed by said
reentrant portion.
23. The device of claim 18 wherein an ancillary absorbent material
is distributed within said aggregate.
24. The device of claim 17 wherein said pieces are irregularly
shaped.
25. The device of claim 24 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
26. The device of claim 17 wherein the size of substantially all of
said pieces is within the range of from about 1/16 to about 1.0
inch.
27. The device of claim 17 wherein said overwrap is essentially
tubular, each longitudinal end of the tubular overwrap is gathered
radially inwardly to form a closure, one longitudinal portion of
the overwrap is a reentrant portion and another longitudinal
portion of the overwrap is an exterior portion, said exterior
portion forms the outer surface of said device, and said reentrant
portion is reentrant upon the combination of said aggregate and
said exterior portion, whereby said device has a cavity
therewithin, said cavity extending substantially from one
longitudinal end of said device toward the opposit longitudinal end
and the interior surface of said cavity is formed by said reentrant
portion.
28. An absorptive device, comprising: an absorptive tampon, a
tubular inserter, and ejection means operatively associated with
said tampon and said inserter for releasing said tampon from said
inserter into a body cavity; said tampon being an aggregate of
individual pieces of absorbent foamlike material, said absorbent
material having a dry aggregate modulus of compression at 25
percent compression in the range of about 0.004 to about 0.050 psi,
an ancillary absorbent material being distributed within said
aggregate, and said aggregate and ancillary absorbent material
being encased within a flexible fluid-permeable overwrap, said
tampon being resilient compacted within said inserter, whereby the
tampon is easy to eject from the inserter.
29. An absorptive device, comprising: an absorptive tampon, a
tubular inserter, and ejection means operatively associated with
said tampon and said inserter for releasing said tampon from said
inserter into a body cavity; said tampon being an aggregate of
individual pieces of absorbent foamlike material, said aggregate
being encased within a flexible fluid-permeable overwrap, the
volume packing factor of said tampon being less than or equal to
about 2.0 cubic inches of the absorbent material per cubic inch
available within the overwrap, said tampon being resiliently
compacted within said inserter, whereby the tampon is easy to eject
from the inserter.
30. An absorptive device, comprising: an absorptive tampon, a
tubular inserter, and ejection means operatively associated with
said tampon and said inserter for releasing said tampon from said
inserter into a body cavity; said tampon being an aggregate of
individual pieces of absorbent foamlike material, an ancillary
absorbent material being distributed within said aggregate, and
said aggregate and ancillary absorbent material being encased
within a flexible fluid-permeable overwrap, said tampon being
resiliently compacted within said inserter.
Description
FIELD OF THE INVENTION
This invention relates generally to absorbent products designed to
absorb body fluids and more particularly concerns catamenial
receptors designed to be worn within the vagina while receiving
catamenia of women and most particularly concerns tampons having an
absorbent body which comprises pieces of absorbent foam held
together as an aggregate by an overwrap.
DESCRIPTION OF THE PRIOR ART
Tampons of the prior art which can be inserted by the user herself
are generally rigid, i.e., have a high modulus of compression, have
a very low resiliency, and are small in cross section in order to
attain insertion, wearing and removal comfort. Tampons presently in
use generally are fibrous assemblies which are highly compressed
into cylinders approximately 11/2 to 2 inches long and 1/2 inch in
diameter. These fibrous tampons are highly compressed to facilitate
insertion and do not expand, if they expand at all, until contacted
by the fluid to be absorbed.
The tampons of the prior art do not allow the absorbent material to
perform as effectively and efficiently as possible due to the
limited absorption surface available and/or stresses imposed on the
absorbent material which prevent full utilization of its potential
capacity as an absorbent material.
Prior art tampons are generally limited with respect to capacity,
containment, and absorption rates. They are limited in capacity in
that the tampon contains a relatively small amount of absorptive
material and is highly compressed. Thus, a large "void volume,"
i.e., unoccupied space within the absorbent body in the vagina
which will act as a reservoir for the menstrual fluid is not
available. They are limited in containment because they are small
in size and do not fill out the vagina to prevent fluids from
flowing around them or bypassing them. They are limited in
absorption rate because they have a small surface area available
for contact with the fluid and can only take on so much fluid
within a given time even though the wicking within them is
good.
Applicant's invention provides a solution to the drawbacks of the
prior art tampons in that it establishes and thereafter maintains a
large void volume within the vagina and, therefore, has a greater
capacity; it is large enough to fill out substantially the entire
cross-section of the vagina and, therefore, provides containment;
it has a large available surface area which has resulted in
unexpectedly high absorption rates; and is comfortable to insert,
wear, and remove.
OBJECTS OF THE INVENTION
Accordingly, it is an object of this invention to provide an
absorptive device which establishes a large void volume very soon
after insertion into a body cavity and thereafter maintains said
void volume.
It is another object of this invention to provide an absorptive
device having a large volume and cross section in its dry
state.
It is also an object of this invention to provide an absorptive
device having high initial and overall absorption rates.
In addition, it is an object of this invention to provide an
absorptive device which is readily disposable in conventional
sewage systems.
It is also an additional object of this invention to provide a
tampon with the above features which is comfortable to insert by
the user, and is confortable during wearing and removal.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an
absorptive device comprising an aggregate of individual pieces of
absorbent foamlike material encased within a flexible
fluid-permeable overwrap, the absorbent material is flexible and
resilient and has a dry aggregate modulus of compression at 25
percent compression in the range of about 0.004 to about 0.050
pounds per square inch, whereby the aggregate is maintained by the
overwrap and also the catamenial device is soft, highly
compressible and conformable to its surroundings, and
resilient.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing
out and distinctly claiming the subject matter which is regarded as
forming the present invention, it is believed that the invention
will be better understood from the following description taken in
connection with the accompanying drawings, in which the thicknesses
of some of the materials are exaggerated for clarity and in
which:
FIG. 1 is an elevation of a tampon of this invention with the
overwrap partially cut away to permit illustration of the tampon
interior;
FIG. 2 is a perspective of another embodiment at one stage in its
formation and wherein the overwrap is cut away for illustrative
purposes;
FIG. 3 is a perspective view of the embodiment of FIG. 2 in its
formed configuration;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3;
FIG. 3 is an enlarged schematic perspective view of a series of
polyurethane cells;
FIG. 6 is a perspective view of an alternate embodiment;
FIG. 7 is an enlarged fragmentary perspective view illustrating the
attachment of a withdrawal string to a tampon of this
invention;
FIG. 8 is a cross-sectional view of the tampon of FIG. 1 in a
telescoping tubular inserter; and
FIG. 9 is a cross-sectional view, similar to FIG. 4, showing an
alternate embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, there is shown a tampon 21 of this
invention comprising an aggregate 24 of individual and separate
pieces 22 of absorbent foamlike material. The aggregate 24 is
wholly encased within the overwrap 23 and the withdrawal string 25
is securely attached to the overwrap 23.
A tampon of this invention as shown in FIG. 1 can be made in the
following manner. The overwrap can be formed from a rectangular
piece of material by bringing two opposite edges of the rectangular
piece together to form a tube having a longitudinal seam such as
seam 50 which is secured by any of well known methods, such as
sewing or gluing. One end of the formed tube can then be gathered
radially inwardly and fastened to form a closure, such as distal
end 37. This closure can be held by any of many various well known
means such as sewing, gluing, or tying with a string. The overwrap
at this stage is tubular with distal end 37 closed and proximal end
38 open. The pieces 22 comprising the aggregate 24 then are placed
within the bag and the proximal end 38 of the tubular overwrap is
gathered radially inwardly and fastened to form a closure so that
the finished overwrap has both ends closed. Thus the overwrap is
essentially tubular and the tampon cylindrical.
A withdrawal string 25 is attached to the overwrap of the tampons
of this invention due to the lack of tensile property within the
aggregate 24 itself. The withdrawal string 25, of course, provides
a means of withdrawing the tampon from the vagina after the tampon
is soiled. A withdrawal string 25 can be attached to or otherwise
associated with the overwrap in many different ways, some of which
are: threading a doubled string through the overwrap, preferably
through a gathering of the overwrap such as may exist at a closed
end, to form a loop and passing the free ends of the string 25
through the loop, such as is shown in more detail in FIG. 7, or
fixing the string 25 to the surface of the overwrap by sewing or
bonding it thereto sufficiently to withstand forces encountered
during withdrawal, or by tying the string 25 around a gathered end
of the overwrap. In a tampon of the structure of FIG. 4, i.e.,
having a reentrant portion 28 of the overwrap, the string 25 can
also be threaded, if desired, through reetrant end 31 to insure
reentrant end 31 remains adjacent closed end 29.
The expression "gathered" as used herein is intended to include any
bringing together of the overwrap at a longitudinal end to form a
closure of the overwrap at that end, e.g., a closure in which the
overwrap is omnidirectionally gathered radially inwardly, as if
drawn by a drawstring; a fin seal wherein the terminal end is
flattened to a single plane by forces perpendicular to the plane; a
lapped joint wherein the terminal end is folded inwardly and
diametric portions of the end overlap, etc. A terminal end of the
overwrap or any portion of the overwrap can be any extremity or
margin of the overwrap, such as is indicated by end 31 in FIG.
2.
Referring now to FIG. 3, an alternate embodiment tampon of this
invention (hereinafter referred to as rosette) is shown which has a
cavity therein formed by a reentrant portion 28 of the overwrap.
The tubular shaped overwrap used for the rosette is slightly longer
than the overwrap 23 of FIG. 1 and it comprises an exterior portion
27 and a reentrant portion 28 as indicated in FIG. 2. The distal
end 29 of the rosette is gathered and secured by any of the means
well known for forming a closure, for example, sewing or gluing the
gathered end. The overwrap is about twice as long as the overwrap
23 for the tampon of FIG. 1, and the exterior portion 27 and the
reentrant portion 28 each are about 50 percent of the length of the
tubular overwrap. The absorbent body which is an aggregate 24 of
pieces 22 is placed within the overwrap and, depending upon the
packing factor (defined infra) desired, the aggregate 24 may or may
not completely fill out the overwrap. The terminal end of the
reentrant portion 28 at the reentrant end 31 of the overwrap may
be, but does not necessarily have to be, gathered and closed. The
reentrant portion 28 is folded inwardly along the longitudinal axis
of the tampon and the aggregate 24 is shaped to form the cavity in
the tampon of FIG. 3. The surface of the cavity within the tampon
is formed by reentrant portion 28, i.e., reentrant portion 28 is
folded around the cavity end 30 of the aggregate 24 and inwardly
through aggregate 24 to form the rosette structure. This structure
is shown in cross-section in FIG. 4 wherein the reentrant end 31 is
adjacent to the closed end 29. Thus there is formed a tampon
wherein the absorbent body, aggregate 24 of pieces 22, is encased
by an overwrap having an exterior portion 27 forming the exterior
surface of the tampon and a reeentrant portion 28 forming the
surface of the cavity. A withdrawal string 25 can be attached as
described above.
The embodiment shown in FIG. 6 is another rosette, similar to that
of FIG. 3, in that it has the aggregate 24 absorbent body which is
enclosed by an overwrap having an exterior portion and a reentrant
portion, but the shape of the overwrap before the reentrant portion
is tucked inwardly is essentially that of two truncated cones
joined at their large bases. Thus the embodiment of FIG. 6 is
generally conically shaped and has a cavity. Also, it can have a
withdrawal string attached as has been described above.
The rosette shape is advantageous because its lateral spread when
subjected to a force normal to the tampon's longitudinal axis is
greater than the lateral spread of a tampon without a cavity in the
middle, e.g., a cylindrical tampon. The greater lateral spread is
beneficial because the vagina exerts a normal force on the tampon
causing the tampon to spread outward toward the lateral walls of
the vagina and the spreading prevents menses from bypassing the
tampon. Another advantage of the rosette shape is that it provides
a larger periphery for a given amount of aggregate than a tampon
without a cavity therein.
The tampon of this invention can be inserted into a vagina via a
telescoping tube type inserter, as is well known to those of
ordinary skill in the tampon art. One such inserter having inwardly
tapering flexible segments at the leading end to form a normally
closed, smooth, openable, leading end is shown in FIG. 8 with the
tampon 21 of FIG. 1 held therein. The inserter used with the tampon
of this invention was molded from polyethylene, but can also be
made of other materials well known to men of ordinary skill in the
tampon inserter art. The tampon 21 is resiliently compacted and
maintained in that condition before and during insertion by placing
it in the tubular inserter 35. Resiliently compacted as used herein
means compressed to a degree such that the absorptive body takes on
a readily releasable temporal set, i.e., a set which dissipates in
the absence of liquids after the tampon is ejected from a
constraining means such as an inserter. The overwrap 23 of the
tampon 21 is in contact with the inner surface of the inserter 35.
An ejecting means, such as the ejector 36, removes a tampon from
the inserter. In the embodiment of FIG. 8, ejector 36 pushes
against the rear end of tampon 21 to move it forward in the
inserter, open the closure at the forward end of the inserter and
expel the tampon from the inserter 35.
The tampon, in the inserter used, forces open the segments at the
forward end of the inserter. The inserter 35 is inserted into the
vagina and the tampon 21 is ejected from the outer tube by pushing
the ejector 36 so that it telescopes within the inserter 35. The
inserter 35, with the ejector 36 therein, is removed from the
vagina after the tampon 21 has been fully ejected from inserter 35
and deposited within the vagina.
An alternate embodiment of the tampon of this invention is shown in
FIG. 9 wherein pieces 39 of ancillary absorbent material are
distributed within the aggregate 24 of the foamlike pieces 22. The
ancillary absorbent material is stiffer, i.e., has a highter
modulus of compression, than the absorbent material from which the
pieces 22 are made.
Many different ancillary absorbent materials can be used for
various purposes. One of these purposes is to hold liquids within
the abosrbent body after they have been absorbed and thus reduce
squeeze-out when a liuqid loaded tampon is compressed. An ancillary
absorbent material which has been found to perform satisfactory in
the tampon of this invention is a cross-linked carboxymethyl
cellulose such as is disclosed in U.S. Pat. No. 3,589,364 issued to
Dean et al. on June 29, 1971, said patent being incorporated herein
by reference. Other ancillary absorbent materials may be used, for
example, carboxymethyl cellulose, primarily insoluble,
polyacrylamides, primarily cross-linked, specific starch
derivatives, all of which are well-known to those of ordinary skill
in the art. Of course, there are many other ancillary absorbent
materials which can be included in the tampon of this invention and
applicant does not disclaim any of these.
The pieces 39 of ancillary absorbent material included in a tampon
of this invention can be of many various sizes, shapes and forms
and located in various positions within the tampon. In a preferred
embodiment, the pieces 39 are small, i.e., regular parallelepipeds
approximately 1/8 .times. 1/8 inch squares cut from a 1/16 inch
thick sheet of the cross-linked carboxymethyl cellulose. These
pieces 39 are then substantially uniformly distributed throughout
the aggregate 24. The percentage, by weight, of the pieces 39 based
on the aggregate 24 ranges from approximately 10 precent to 50
percent, preferably from about 15 percent to 30 percent. The most
preferred percentage of cross-linked carboxymethyl cellulose used
in several instances was about 20 percent to 25 percent.
Alternate forms of small pieces 39 of the ancillary absorbent
material are pellets and individual cellulosic fibers. Thin rods or
bars of the ancillary material can also be used. These alternate
forms of the pieces 39 can be located in many positions within the
absorbent body of the tampon, such as uniformly distributed
throughout the aggregate 24, as shown in FIG. 9, or concentrated in
particular positions in the aggregate 24, such as near the
reentrant portion 28 of the overwrap.
The fit of the overwrap 23 about the aggregate 24 is preferably
loose to a degree rather than tight and can be described by a
packing factor or a volume-length factor in conjunction with an
overwrap cross-sectional area (defined infra). A loose overwrap
makes the tampon look and feel fluffy and soft. A loose overwrap
also promotes absorption characteristics and wearing and removal
comfort as indicated by the data in Table III infra.
The fit of the overwrap 23 about the aggregate 24 also affects
ejection force such that with equal amounts of absorbent material,
the ejection force is generally lower if the packing factor is
higher, i.e., if the overwrap fit is tighter. See Table III infra.
For this reason and others explained hereinafter, the looseness of
overwrap, i.e., packing factor, is critical to achieve an optimum
balance of certain desirable tampon characteristics. A loose
overwrap about an aggregate 24 of low modulus of compression
(defined infra) pieces 22 to give a packing factor within a range
defined infra will promote removal comfort, i.e., lack of
discomfort when the tampon is removed from a vagina. It is believed
that removal comfort is enhanced because the pieces 22 can shift
with respect to each other as they are compressed to conform to the
introital orifice; thus dilation of the introitus during removal is
gradual and easier due to the low modulus of the aggregate 24 and
relative motion permitted between adjacent pieces 22. Relative
motion between pieces 22 occurs because the pieces 22 are
relatively loose within the overwrap 23 rather than being tightly
packed within the overwrap. Thus, since the introitus is a
constricting band of muscles which can be dilated, a soft,
conformable tampon will take on a wedge shape having a gradually
increasing diameter to gradually dilate the introitus, rather than
sharply dilating the introitus, to enhance the removal comfort of
the tampon. During removal, as can be visualized from FIG. 4, the
closed end 29 is the leading end and the cavity end 30 is the
trailing end. The eccentric portions of closed end 29 are forced
towards the rear by the constriction of the introitus such that end
29 is formed into a conically shaped leading end. The aggregate 24
near the closed end 29 is thus compressed and moved toward the rear
to form a tampon with a gradually increasing diameter so that the
largest diameter encountered during removal is not at the leading
end.
The looseness of the overwrap can be more precisely defined in
terms of a volume packing factor. The volume packing factor is the
volume of the integral, i.e., uncut, absorbent material used to
provide the aggregate 24 divided by the maximum volume enclosable
by the overwrap, i.e., cubic inches of absorbent material per cubic
inches within the overwrap. The volume of absorbent material as
used in the packing factor can be calculated for any specific
tampon by dividing the weight of the aggregate 24 by the density of
the absorbent material before it is cut up. A weight packing factor
can also be determined for tampons of this invention by dividing
the weight of aggregate 24 by the maximum volume enclosable by the
overwrap.
A tampon which will conform and gradually ease the introitus open
to promote removal comfort should have a packing factor which will
allow some conformation by the aggregate to the introital openings
but not be loose enough to permit all of the aggregate to shift to
the rearmost portion of the overwrap as the tampon is withdrawn. A
shift to the rearmost portion of the overwrap of too much of the
aggregate 24 could allow an accumulation at the rear of the tampon
which would require an abrupt dilation of the introitus and
increased removal discomfort.
The pieces 22 were cut or made from an absorbent foamlike material
having a low dry bulk modulus of compression preferably in the
range of about 0.2 to about 2.0 pounds per square inch and more
specifically in the range of about 0.2 to about 0.8 pounds per
square inch. The work "dry" when used herein in conjunction with
modulus of compression is intended to indicate the moisture content
condition of the material as it is compacted within an inserter or
before it is released from the inserter, generally the conditions
as set forth in ASTM Test D1564, "2. Test Conditions." The word
"wet" when used with modulus of compression indicates the material
has been fully wetted by an excess of water and then squeezed or
centrifuged to remove the excess water. The minimum modulus of
compression is required to acquire absorption capacity and the
maximum modulus of compression is required to achieve a comfortable
tampon. This bulk modulus of compression is established in
accordance witn ASTM test D1564, Compression Load Deflection Test
(suffix D) at 25 percent compression. The term "absorbent foamlike
material" is intended to encompass three dimensional absorptive
materials such as gas blown foams, natural sponges, cellulose
sponges, and composite fibrous based structures such as taught in
U.S. Pat. Nos. 3,311,115 and 3,430,630 (incorporated herein by
reference).
Bulk moduli of compression of two foamlike absorptive materials are
given in Table I below. The samples from which the bulk moduli were
obtained were 2 inches on a side for the washed Hydro-Foam.sup.TM
and 1 inch on a side for the unwashed Hydro-Foam.sup.TM and the
Grecian silk sponge which is taught by the prior art. All wet bulk
moduli were based on the dry dimensions of the samples because the
samples swelled when wetted.
All Hydro-Foam.sup.TM referred to infra is washed unless unwashed
is specifically stated. The absorptive material was washed by
running it in the rinse cycle of a standard home-type automatic
clothes washing machine with distilled water for about 20 minutes
and then drying it in a standard home-type clothes dryer for about
3 hours.
TABLE I - BULK MODULUS OF COMPRESSION OF FOAMLIKE ABSORBENT
MATERIALS ______________________________________ DRY WET Avg. (psi)
High (psi) Low (psi) Avg. (psi) High (psi) Low (psi)
______________________________________ 25% Compression
Hydro-Foam.sup.TM 0.38 0.19 Hydro-Foam.sup.TM (unwashed) 0.62 0.64
0.60 0.26 0.27 0.25 Grecian Silk Sponge (unwashed) 6.9 11.7 4.5
0.90 1.2 0.5 80% Compression Hydro-Foam.sup.TM 1.30 1.10
Hydro-Foam.sup.TM (unwashed) 2.74 2.80 2.70 2.60 2.97 2.00 Grecian
Silk Sponge (unwashed) 40.7 50+ 26.8 6.1 11.1 2.8
______________________________________
Another and perhaps more relevant measure of the stiffness of the
absorbent material is the modulus of compression of the aggregate
24 of pieces 22 comprising the absorbent body (said modulus
hereinafter referred to as the aggregate modulus). The aggregate
modulus indicates the compression force required to effect a
specified deflection of a mass of the particulate absorbent body.
The aggregate to be measured is at an equilibrium undistorted
condition as set forth in ASTM D1564, "2. Test Conditions." The
aggregate modulus is perhaps a more relevant measure to use because
this is the actual modulus of the absorbent body forming the tampon
of the invention, and as such more directly influences the ejection
force of the tampon from an inserter and the wearing and removal
comfort of the tampon.
There is a difference in both degree and kind between the bulk
modulus and aggregate modulus of a foamlike absorptive material.
The bulk modulus is different in degree in that it is substantially
greater than the aggregate modulus. The bulk modulus under ASTM
Test D1564, (Suffix D) at 25 percent compression of one
polyurethane foam used was 0.40 psi, while the aggregate modulus of
the same material at 25 percent compression was 0.03 psi. The bulk
modulus is different in kind in that the behavior of the bulk,
i.e., integral, absorbent foamlike materials under compression is
such that the stress-strain curve of the bulk material is initially
steep, i.e., a large increase in deformation for a small increase
in force applied, and then appears to take on the general form of
deformation equals K + L log (force) where K and L are constants.
In contrast, the stress-strain curve of the aggregate as appears to
immediately follow the general form of deformation equals K' + L'
log (force) where K' and L' are constants.
The aggregate modulus of the aggregate for the tampon of this
invention was measured in accordance with ASTM test D1564,
Compression Load Deflection Test (Suffix D), modified as follows: A
cylinder-piston device with a low height-to-diameter ratio was used
to contain the aggregate. The cylinder was filled with aggregate to
a uniform depth. The cylinder in this instance was made of a
transparent plastic, plexiglas, had a bottom which closed one end,
had an inside diameter of 240 millimeters, and was 10 centimeters
deep. The piston also was made of plexiglas and consisted of a 44
millimeter diameter rod about 5 inches long glued to a 239
millimeter diameter, 5 millimeter thick plexiglas plate. The plate
or piston head of the piston had holes drilled through it in order
that air trapped between the cylinder and the piston head could
escape without exerting a noticeable force on the piston head.
The force and deflection measurements for determining modulus of
compression were made with an Instron Universal Testing Instrument.
The cylinder was attached to the Instron compression cell and the
piston was attached to the Instron crosshead.
Each specimen of aggregate absorbent body used in obtaining an
aggregate modulus of compression was preflexed twice to 75 to 80
percent of its original volume within the cylinder and then allowed
to rest under no load for 10 minutes prior to testing. Three
different specimens of aggregate absorbent material were measured
to determine the aggregate modulus of a specific aggregate, i.e., a
sample of aggregate. Each specimen was a fresh refill of the
compression cylinder to a minimum depth of 1 inch. The aggregate
modulus reported for an aggregate absorbent body was the mean of
the specimens. If the aggregate modulus of compression of any
specimen deviated from the mean by more than 20 percent, two
additional specimens were run. The aggregate modulus of that
aggregate absorbent body then was reported as the mean of all 5
specimens.
The aggregate modulus of any one specimen of an aggregate absorbent
body was determined as follows: First the Instron was warmed up and
the compression cell of the Instron was calibrated with a known
weight and with the empty compression cylinder on the compression
cell table. The piston was attached to the crosshead of the
Instron. Second, the chart speed was set at 5 inches per minute and
the crosshead speed was set at 2 inches per minute. Third, the
compression cylinder was filled with the specimen to a level of 1
inch in depth by allowing the aggregate to fall from a height of
about 5 inches above the bottom of the cylinder. Any and all clumps
within the specimen were broken up before they were allowed to fall
into the cylinder. The top surface of the sample within the
cylinder was made as level as possible. The depth of the aggregate
absorbent body was measured by placing a spare plate, i.e., one
identical to the plate used as the piston head but not having the 5
inch, 44 millimeter diameter rod attached thereo, on top of the
specimen and measuring the thickness of the specimen from the
bottom of the cylinder to the bottom of the spare plate. This depth
was not less than 1 inch. Fourth, the pen of the Instron was zeroed
with the filled cylinder on the compression table of the Instron.
Fifth, the piston was brought into contact with the specimen and a
preload of 0.02 pounds per square inch (psi) was applied to the
specimen. The depth of the specimen was then measured while it was
under the preload of 0.02 psi, and the crosshead travel required to
produce the desired percent compression was determined based on the
depth of the specimen at the specified preload. Sixth, the specimen
was compressed to the desired percent compression and held at that
compression for 1 minute. The load required after 1 minute to
produce the desired percent compression was recorded. Seventh, the
specimen was returned to 0 percent compression by retracting the
piston from the sample.
The aggregate modulus for the specimen was then determined by
dividing the load measured at the desired percent compression by
the contact surface area of the piston.
The dry aggregate modulus of the absorptive body used in a tampon
of this invention must be below a certain level to provide an
acceptable tampon. If the dry aggregate modulus is too high, the
tampon will be too stiff, thus causing unacceptably high ejection
forces and/or discomfort during wearing or removal. Preferably, the
dry aggregate modulus at the 25 percent compression level should be
in the range of 0.004 to 0.050 psi, more preferably in the range of
0.004 to 0.030 psi.
The aggregate 24 of this invention should preferably be, but need
not necessarily be, mensesphilic, i.e., have surface
characteristics such that the menstrual fluid tends to spread
readily or spontaneously on the surface and in the capillaries.
Since the menstrual fluid is primarily an aqueous solution,
materials onto and into which it spreads readily could be loosely
described as hydrophilic. However, the state of the art respecting
wetting of materials allows a more precise description in terms of
contact angles and surface tensions of the fluids and solids
involved. This description is disclosed in detail in the American
Chemical Society publication entitled Contact Angle, Wettability
and Adhesion, edited by Robert F. Gould, and copyrighted in 1964;
said publication being incorporated herein by reference.
Menstrual fluid has a surface tension range of about 35 to 60 dynes
per centimeter. It will have a contact angle of less than
90.degree. and will tend to spread spontaneously on a solid which
has a critical surface tension value greater than its surface
tension. Since the surface tension of water is higher than that of
menstrual fluid, any solid which is hydrophilic is also usually
mensesphilic.
The absorptive material used for making the aggregate 24 should
desirably have a critical surface tension at least greater than 35
dynes per centimeter, preferably greater than 60 dynes per
centimeter, and more preferably greater than the surface tension of
water which is about 72 dynes per centimeter.
The absorptive foamlike material and the aggregate 24 made from
these materials which is used in a tampon of this invention should
be resilient. One test for resiliency is a Compression Set Test, a
modification of ASTM D1564, Compression Set Test, run on an Instron
Universal Testing Instrument wherein the sample is compressed to 80
percent of its dry height, released, and the percent recovery of
the sample is measured. The percent recovery can be measured by
placing a quantity of aggregate 24 in a 4 inch diameter cylinder,
placing a piston connected to the Instron load cell within the
cylinder, compressing the aggregate to 20 percent of its dry
height, backing the piston away from the compressed aggregate, and
measuring the rebound height of the aggregate after about 30
seconds. The percent recovery then is [rebound height divided by
the initial height] times 100. The percent recovery for a dry
aggregate of pieces 22 should be a minimum of about 91 percent and
preferably about 97 percent in order that a resiliently compacted
aggregate tampon will expand before being wetted after being placed
in a vagina, so that the tampon fills the vaginal cross-section
soon after placement.
Absorptive materials which work well for the pieces 22 for the
tampon of this invention are absorbent materials having adjacent
cells such as cells 32 and 33 shown in FIG. 5 wherein adjacent
cells can communicate with each other if a common wall 34 is
ruptured, in which case a fluid within cell 32 can move from cell
32 to adjacent cell 33. Hydrophilic polyurethane foams have
adjacent cells such as cells 32 and 33, which can be made
communicating by reticulation, a breaking of inter cellular walls,
of the foam, and such foams are described in detai in the commonly
owned, copending, U.S. Pat. application entitled COMPLIANT
CONFORMABLE TAMPON, U.S. Ser. No. 172,694, filed Aug. 18, 1971,
incorporated herein by reference. One of those polyurethane foams,
i.e., Hydro-Foam.sup.TM, which has been used and produces a
satisfactory tampon of this invention is available from Scott Paper
Company, Foam Division, Eddystone, Penna. The Hydro-Foam.sup.TM is
hydrophilic and wet swelling. It was found to have a cell count of
approximately 80 cells per inch, a density of about 1.9 to 2.3
pounds per cubic foot, and a dry bulk modulus of compression of
about 0.4 pound per square inch after being washed.
In a successfully executed embodiment of a tampon of this
invention, the foam forming the absorbent body, i.e.,
Hydro-Foam.sup.TM, had a density of about 0.596 grams per cubic
inch, weighed about 2.5 grams and was cut into pieces 22 which had
a size of 3/8 inch and smaller. "Size" as used herein in describing
pieces 22 is intended to indicate the size of piece which will
pass, with vibration, through a U.S. Standard Sieve having a mesh
opening of the stated size, but not through the next smaller sieve.
Thus, a piece 22 having a size of 3/8 inch will pass through a
sieve having a 3/8 inch mesh opening, but not through a 0.265 inch
sieve. The size of the pieces 22 can vary widely, with a maximum
size of about 1 inch, but preferably having a size in the range of
about 1/16 inch to about 5/8 inch. The smallest acceptable size is
determined by whether the piece 22 will absorb and whether it will
be retained by the overwrap. The largest acceptable size for a
piece 22 is determined by whether that size piece will form a
smooth aggregatable absorbent body.
Of course, the absorbent body can be an aggregate of various sized
pieces or of substantially uniformly sized pieces. When uniformly
sized pieces 22 are used as the absorbent body, there is a minimum
acceptable size for the pieces 22 in order that the tampon has the
resiliency required to fill the vaginal cross-section and the
modulus of compression required to maintain a void volume as a
fluid reservoir within the vagina. Band Compression Modulus
(hereinafter defined) was measured on rosette tampons wherein the
maximum outer diameter of the overwrap was about 2 inches and the
length of the rosette was about 21/2 inches. Unwashed
HydroFoam.sup.TM was used as the absorptive material, the pieces 22
within any one rosette were essentially uniform in size, each
rosette had a different sized piece 22, and the aggregate 24 within
each rosette weighed about 2.5 grams. The Band Compression Modulus
for each tampon having uniformly sized pieces 22 is shown in Table
II below. The minimum acceptable piece 22 size for a tamping of
this invention is about 1/16 inch. The aggregate 24 of pieces 22
need not be coherent in and by itself because the overwrap will
maintain the aggregate.
TABLE II - UNIFORM PIECE SIZE VS. BAND MODULUS HYDRO-FOAM.sup.TM
ROSETTE ______________________________________ PIECE SIZE BAND
MODULUS LB. TO REDUCE CIRCUMFERENCE 25% UNWASHED WASHED
______________________________________ 1" 0.53 -- 3/4" -- 0.30 5/8"
0.55 -- 1/2" -- 0.34 3/8" 0.48 0.42 PASSES THROUGH SIEVE SIZE
CAUGHT ON SIEVE SIZE 3/8" 0.265" 0.4 0.33 0.265 0.187 -- 0.25 0.187
0.132 -- 0.28 0.132 0.0937 -- 0.28 0.265 0.0937 0.25 -- 0.0937
0.0661 0.24 0.22 0.0661 0.0469 0.17 0.19 0.0469 0.0197 0.12 0.13
______________________________________
Also, the pieces 22 need not necessarily be uniformly shaped, in
fact, they preferably are very irregularly shaped such as would
result by chopping in a Waring kitchen blender. Pieces 22 were
chopped for the tampon of this invention in a Waring kitchen
blender by putting blocks of Hydro-Foam.sup.TM in the blender.
Pieces 22 also have been made irregularly shaped by comminuting
Hydro-Foam.sup.TM and other similar polyurethane foams in a fixed
blade comminutor, such as a Fitz Mill available from the
Fitzpatrick Company. Pieces 22 have also been cut from polyurethane
foams with a scissors into uniform shapes, i.e., in the form of
cubes of various sizes.
The material used as the overwrap of this invention preferably is a
soft, flexible, fluid permeable material having small apertures
therethrough. A biodegradable material is desirable for the
overwrap because it will enhance the destructability of disposed
tampons. Two nonwoven fabrics which have functioned well as the
overwrap and are believed to be biodegradable are: Dexter X-2172, a
nonwoven fabric consisting of approximately a 60:40 cotton:rayon
blend, saturation bonded with a mixture of HA8 and HA24, Rohm &
Haas acrylic binders, said fabric having a measured weight of about
0.6 to 0.7 ounce per square yard and being hydrophobic and
available from C. H. Dexter & Sons Co., Windsor Locks,
Connecticut; and Viskon, a 100 percent rayon, nonwoven, line-bonded
material, which is hydrophilic, has a measured weight of about 0.47
ounce per square yard, and is available from Chicopee Mills, 1450
Broadway, New York, N.Y.; Reemay, a hydrophobic, spunbonded, low
basis weight, polyester nonwoven fabric having a measured weight of
about 0.4 ounce per square yard and available from E. I. Du Pont de
Nemours, Wilmington, Del., is another nonwoven which has performed
satisfactorily as an overwrap for tampons of this invention. Use of
a highly hydrophobic material as the overwrap with a highly
absorptive absorbent body can be advantageous in that it insulates
the vaginal wall from collected menses and thus maintains, during
menstruation, the slightly acidic condition of the vagina which
exists during non-menstrual times.
The above nonwoven fabrics have no noticeable apertures therein,
but some materials having noticeable apertures have been used
satisfactorily. The purpose of keeping the apertures small is to
prevent small pieces 22 from escaping through the overwrap and to
prevent edges or corners of larger pieces 22 from projecting
through the overwrap. The nominal and potential apertures, i.e.,
opened areas or areas encompassed by adjacent fibers, in the
overwrap should not exceed a size which will prevent pieces 22 from
escaping from the overwrap or from protruding therethrough such as
to interfere with the ejection force of the tampon from a tubular
inserter. Some foam-like materials, e.g., polyurethane, have a high
coefficient of friction with inserter materials like polyethylene
or paperboard. The static coefficient of friction of polyurethane
with polyethylene is about 1.05. Therefore, the nominal and
potential apertures within the overwrap should be no greater than
the smallest piece 22 comprising aggregate 24. The potential
apertures can be much larger than the nominal apertures when the
crossover points within the overwrap are not bonded. It has been
found that a woven overwrap having an interfiber distance of about
1/8 inch in both directions and having no attachment at the
crossover points is not acceptable in that the ejection force from
a telescoping tubular inserter for that tampon is increased (see
Table V below). For such an inserter, it is thought preferable to
exclude the pieces 22 from the exterior surface of the tampon in
order to maintain a smooth exterior surface and a low coefficient
of friction. It has been found that overwraps having apertures with
diameters as large as 1/16 inch, when the pieces 22 are a mixture
of sizes from about 1/16 inch to about 3/8 inch, do not prove
detrimental to the functioning of the tampon.
It is believed desirable to maintain the exterior surface of the
tampon as smooth and having as low a coefficient of friction as
possible for at least two reasons: to achieve a low ejection force,
i.e., the force required to eject the tampon 21 from a tubular
inserter such as inserter 35 (see FIG. 8), and to prevent scraping
of the soft, tender tissue within the vagina during insertion,
wearing, and removal. In general, the absorbent material from which
the pieces 22 are made has a higher coefficient of friction than
the overwrap material and, therefore, any protrusion of the pieces
22 through the overwrap would result in an increase in the ejection
force and the scraping of the tissue within the vagina.
The overwrap should have a static coefficient of friction with the
interior of the inserter of less than about 0.40, and preferably
less than about 0.37, to provide acceptable ejection forces with
larger tampons of this invention. Overwraps having a coefficient
substantially higher than 0.40 result in ejection forces which are
substantially higher and prove to be objectionable by users.
The overwrap should have strength characteristics so as to prevent
the nonwoven material from rupturing during removal or from vaginal
pressures while in vivo. The overwrap should have a wet tensile
strength in the machine direction of at least about 600 grams per
inch and in the cross direction at least about 250 grams per inch.
The minimum wet internal tearing resistance as measured by TAPPI
Standard T 414 ts-65 in the machine direction for the overwrap
should be about 100 grams to tear 16 plies 2 inches to prevent the
overwrap from tearing during removal of the tampon from the
vagina.
A material which has worked well as a withdrawal string is a
waterproofed cotton string having a 5/3 ply and a 9 pound tensile
strength. Such a string is available from Bibb Manufacturing
Company, Macon, Ga. under the name of 5/3 ply Sno-Spun bleach 108
cotton.
Any string sufficiently strong to withstand removal forces can be
used as the withdrawal string 25. The polyester strings generally
have a higher tensile strength and can be used if a stronger string
is desired. Polyester strings are available from UniRoyal Fiber
& Textile, Division UniRoyal, Incorporated, 350 Columbia Road,
Winnsboro, S.C., 29180.
A tampon of this invention made with the aforementioned
Hydro-Foam.sup.TM as the absorbent material requires a minimum of
about 1.00 gram and preferably more than about 1.5 grams of the
absorbent material to acquire adequate performance with the tampon.
Adequate performance encompasses at least both absorption capacity
of the tampon and bypass control. To achieve bypass control, the
tampon should preferably have a nominal outside diameter of at
least about 1.75 inches, which provides a nominal periphery of at
least about 5.5 inches. The nominal diameter, periphery,
cross-sectional area, and volume available within the overwrap
(hereinafter referred to) is intended to be the dimension of the
overwrap in its fullest radially extended form, resulting in a
generally circular cross-section, rather than a partially collapsed
form which occurs when the aggregate is not large enough to fill
the overwrap. Also, the cross-sectional area or volume available
within the overwrap does not include the area or volume in the
cavity of the rosette. The overwrap for a rosette shaped tampon was
made from the above mentioned Reemay, and was a rectangular piece
about 61/2 by 63/4 inches. The overwrap material was formed into a
tube in the manner described above with a 63/4 inch dimension
forming the circumferential periphery of the overwrap and allowing
approximately 1/2 inch of the 63/4 inch dimension for the seam. A
rosette made from the above size overwrap is about 21/2 inches long
and about 2 inches in diameter.
The maximum amount of the above mentioned Hydro-Foam.sup.TM which
can be incorporated into a tampon of this invention appears to be
limited by the maximum inserter diameter which can comfortably be
inserted by a user. Thus limited by an inserter having an inside
diameter of about 0.71 inch, the maximum amount of the absorptive
material which could be used in a 21/2 inch long tampon of this
invention was about 5.25 grams when the pieces 22 were a mixture of
1/16 to 3/8 sized pieces. The inserter size limited the inclusion
of more absorptive material because the ejection force required
became too great to allow comfortable ejection even with a tight,
low coefficient of friction overwrap. The ejection force
encountered with 5.25 grams of the absorptive material and the
Reemay overwrap in a polyethylene inserter such as shown in FIG. 8
having an inside diameter of about 0.71 inch was about 3.5
pounds.
A preferred embodiment, which is certainly not the only operative
embodiment, was made as follows: Rosettes were made in accordance
with the structure shown in FIG. 3 from 61/2 by 63/4 inch
rectangles of the above mentioned Reemay overwrap material, 21/2
grams of the aforementioned Hydro-Foam.sup.TM absorbent material,
and the 5/3 ply withdrawal string. The overwrap material was formed
into a tubular shape by folding the rectangle on the 63/4 inch
dimension, overlapping the oppositely disposed marginal edges, and
sewing together the superposed marginal edges and one of the
terminal ends to form a bag configuration. The bag was then
inverted and the sewing along the marginal edge formed a seam such
as seam 50 in FIG. 3 and the sewing along the terminal end formed a
closed end such as distal end 29 in FIG. 3. The 21/2 grams of
absorptive material was chopped up as above described in a Waring
kitchen blender such that the pieces 22 were of various sizes and
the largest sized piece 22 was about 3/8 inch. The absorbent
material was placed within the inverted bag and the terminal end of
the bag such as reentrant end 31 of FIG. 2 was sewn shut. The
reentrant end 31 was then moved inwardly along the longitudinal
axis of the tampon through the aggregate 24 until the reentrant end
31 was adjacent the closed end 29. The withdrawal string 25 was
then threaded through the closed end 29 with a surgical needle and
secured to the overwrap. Rosettes made according to the above
description are about 2 inches in diameter and about 21/3 inches
long. They have been used as a tampon, both in vivo and in the
"syngyna." The ejection force required to remove them from tubular
inserters is low and their absorption characteristics are
unexpectedly good. Their characteristics are shown in Table III as
Example VIII.
A syngyna is an artificial device used to simulate a vagina. It
consists of a thin rubber membrane which holds the tampon, said
membrane being within an outer case such that water can be
introduced between the membrane and the outer case so that a
hydraulic head can be placed on the exterior of the membrane, and a
tube entering the membrane at its interior end such that the tube
orifice into the membrane simulates the cervical os. A reservoir of
syngyna fluid, said fluid having a viscosity and salinity equal to
that of menstrual fluids, is connected to the tube with a flow
regulator such that the syngyna fluid can be admitted to the
membrane through the tube at a known and variable rate. There are
both static and dynamic syngynas. The hydraulic head is constant in
a static syngyna and the hydraulic head is varied in a dynamic
syngyna. All absorption capacities and rates herein described were
determined in a dynamic syngyna wherein the head was varied from 4
to 16 inches of water at a regular cycle rate of about 4 cycles per
minute. Syngynas are known to persons of ordinary skill in the
tampon art.
Rosettes of various diameters and amounts of aggregate
Hydro-Foam.sup.TM absorbent material were made in the
aforedescribed manner of Example VIII with various sized overwraps
to give the tampon sizes of Examples I through X of Table III. The
tampons of Examples I through X have been tested both in vivo and
in a syngyna. The physical characteristics, unexpected absorption
performance, especially the absorption characteristics being
dependent on the packing factor, and the average weighted comfort
grades of these tampons are given in Table III below and discussed.
The infra "Band Modulus" was measured by slipping a 1 inch wide
Teflon band around the tampon and measuring the force on an Instron
Universal Testing Machine to reduce the circumference of the tampon
to 75 percent of its normal circumference. The "Plate Modulus" was
measured by placing the tampon between two flat plates with the
tampon's longitudinal axis parallel to the plates and measuring the
force on an Instron Universal Testing Instrument required to reduce
the tampon's diameter to 75 percent of its normal diameter. The
ejection force was measured as the force required to eject the
tampon out of a polyethylene inserter such as shown in FIG. 8
wherein the inserter had a 0.71 inch inside diameter, four
segmented petals at its leading end, and a nominal wall thickness
of about 0.015 to 0.025 inch in the petal area. The tampons had
been resiliently compressed in the inserter for at least 2 hours.
The static ejection force is the force required to start the tampon
moving and the dynamic force is the force required to open the
petals and overcome dynamic friction. The "Packing Factor" was
calculated both as the weight and volume of Hydro-Foam.sup.TM per
cubic inch of volume available within the overwrap. The volume of
aggregate was calculated by dividing the integral foam density into
the weight of foam used. It is of interest that the relation
between the Band Modulus and the Volume Packing Factor is
essentially a straight line function. The absorption
characteristics were determined in a syngyna. The syngyna fluid was
"fed" to the tampon as fast as the tampon would absorb it and the
test was stopped as soon as syngyna fluid escaped from the end of
the tampon opposite the end at which the fluid was fed. The "Weight
Gain" was calculated by subtracting initial weight from final
weight of the tampon, "Initial" rate was taken from the time
required for the tampon to absorb the first 5 milliliters of fluid.
"Overall" rate was calculated from "Weight Gain" and time required
to absorb that amount of fluid. "Efficiency" was calculated by
dividing the "Weight of Absorption Material" into "Weight Gain."
Each of the "Average Weighted Comfort Grades" entries are
calculated as: ##SPC1##
where
n.sub.g = number of panelist responses in comfort grade g for that
Example tampon; and
g = a comfort grade.
TABLE III - CHARACTERISTICS OF HYDRO-FOAM.sup.TM ROSETTE TAMPONS
HAVING REEMAY OVERWRAP
__________________________________________________________________________
Tampon Nominal Size Packing Factor Average Weighted Comfort Grades
Example Diameter (inches) Length (inches) Volume within Overwrap
(inches.sup.3) Weight of Absorption Material (grams) Weight (g.
foam/in..sup.3 Volume (in..sup.3 foam/in..sup.3 tampon) Insertion
Wearing Removal
__________________________________________________________________________
I 1.0 21/2 1.81 5.0 2.76 4.64 0.35 0.06 0.18 II 2.0 21/2 6.08 5.0
0.82 1.38 0.29 0.12 0.12 III 2.7 21/2 10.10 5.0 0.50 0.84 0.17 0.44
0.33 IV 1.0 21/2 1.81 3.75 2.08 3.50 0.06 0.17 0.22 V 2.0 21/2 6.08
3.75 0.61 1.03 0.31 0.06 0.13 VI 2.7 21/2 10.10 3.75 0.37 0.62 0.16
0.26 0.37 VII 1.0 21/2 1.81 2.50 1.39 2.34 0.17 0.06 0.17 VIII 2.0
21/2 6.08 2.50 0.41 0.69 0.28 0.11 0.11 IX 2.7 21/2 10.10 2.50 0.26
0.44 0.11 0.11 0.17 X 2.0 21/2 6.08 1.25 0.21 0.35 0.06 0.06 0.06
__________________________________________________________________________
TABLE III
__________________________________________________________________________
Ejection Force Absorption Rate Example Band Modulus (lbs./25%
deflection) Plate Modulus (lbs./25% deflection) Static (lbs.)
Dynamic (lbs.) Syngyna Fluid Weight Gain Initial (ml./min.) Overall
Efficiency of Absorption Material (G. of Syngyna Fluid/G.
Absorption Material)
__________________________________________________________________________
I 2.05 2.45 3.45 3.51 29.8 21.7 16.6 5.9 II 0.44 0.35 3.24 3.45
33.6 26.3 16.3 6.7 III 0.19 0.15 3.66 3.50 41.2 26.4 15.6 8.2 IV
1.53 1.85 1.22 1.72 24.9 8.8 9.6 6.6 V 0.38 0.20 1.97 2.22 28.9
29.4 26.2 7.7 VI 0.19 0.08 2.39 2.75 28.5 29.4 19.9 7.6 VII 0.98
0.49 0.68 1.16 18.8 31.3 23.5 7.5 VIII 0.23 0.11 0.75 1.21 19.9
10.4 15.9 8.0 IX 0.15 0.05 1.14 1.55 20.9 14.7 21.6 8.4 X 0.11 0.04
0.35 0.82 13.7 13.9 13.6 9.1
__________________________________________________________________________
The comfort grades used were 0, 1, 2, and 3 with 0 being no
discomfort, 1 being slight discomfort, 2 being moderate discomfort,
and 3 being severe discomfort. The responses were subjective
evaluations given by a panel of users of the tampons, with each
user using at least one complete array of Examples I through X.
The wearing and removal comfort of the 3.75 gram and 5.00 gram
tampons was unexpected for such large tampons and, of course, is
advantageous in that since they are comfortable, then can be used
and give excellent protection due to their large size which gives
them much more absorbent capacity, and also the capability to block
the vagina and prevent bypass. Also, the fact that comfort is
influenced by packing factor is unexpected and advantageous because
the comfort can be controlled by optimizing the packing factor for
a given weight of absorbent material, modulus of compression of the
absorbent material, and cross-sectional area of the tampon. The
packing factor can be expressed in terms of a volume-length factor
in conjunction with the cross-sectional area available within the
overwrap.
The comfort of a tampon of this invention is dependent on the size
of the pieces 22, the modulus of compression of the absorptive
material, the cross-sectional area available within the overwrap,
and the amount of aggregate 24 within the overwrap. The amount of
aggregate can be defined in terms of a volume-length factor, the
volume of aggregate per unit length of the tampon, which is related
to the volume packing factor for a specific tampon of this
invention and the relationship is: volume-length factor = volume
packing factor X cross-sectional area within the overwrap for the
specific tampon. The volume as used in this factor is the same as
used in the volume packing factor, i.e., the volume of the integral
absorbent material -- not the volume of the aggregate itself. The
volume-length factor thus is expressed in terms of cubic inches of
integral absorbent material to form the aggregate within the tampon
per inch of tampon length. A tampon of this invention that will be
comfortable and provide acceptable protection, i.e., absorption, to
the user has the following structure: The pieces 22 are sized from
about 1/16 inch to about 5/8 inch, preferably from about 1/16 inch
to about 3/8 inch. The dry aggregate modulus of the pieces 22 is in
the range of about 0.004 to about 0.050 psi, preferably about 0.010
to about 0.030 psi. The cross-sectional area within the overwrap is
greater than about 1.75 square inches, preferably greater than
about 2.35 square inches. The volume packing factor is equal to or
less than 2.0 cubic inches of absorbent material per cubic inch
available within the overwrap. The volume length factor is about
1.07 to about 4.0 cubic inches of absorbent material per inch of
longitudinal axis of the tampon; but preferably from about 1.07 to
about 3.02 cubic inches of absorbent material per inch of
longitudinal axis of the tampon when the cross-sectional area
within the overwrap is from about 1.75 to about 3.60 square inches,
and from about 1.07 to about 3.02 - .sqroot.0.99 (x - 3.6), wherein
x is the cross-sectional area within the overwrap, cubic inches of
absorbent material per inch of longitudinal axis of the tampon when
the cross-sectional area within the overwrap is from about 3.60 to
about 6.0 square inches.
The absorption performance of the tampon of this invention is
surprisingly influenced by the packing factor of the tampon as can
be seen from a comparison of equal foam weight rosette tampons
having varying packing factors as shown in Table III. The foam
weight is equal within the set comprising tampons I, II, and III;
the set comprising tampons IV, V, and VI; and the set comprising
tampons VII, VIII, and IX. Now looking closer at the set of tampons
VII- VIII; and IX, just as an example, it is seen that the volume
packing factor for these tampons is 2.34, 0.69, and 0.44,
respectively. That is, tampon VII is packed the tightest and tampon
IX is packed the loosest. The syngyna fluid weight gain for tampon
VII, which has the highest packing factor in the set, at 18.8 grams
is less than the syngyna fluid weight gain for tampon IX, which has
the lowest packing factor in the set, at 20.9 grams.
Also, it is unexpected and surprising to note that the absorption
rates of the variously packed tampons is also affected by the
packing factor in that the absorption rate per square inch of
overwrap cross-sectional area exposed to menses decreases as the
packing factor decreases. In addition, it is noted that the
"Efficiency" of the absorbent material is affected by the packing
factor. The relationship appears to be such that the "Efficiency"
is inversely proportional to the packing factor.
The tampon of this invention has several unexpected advantages over
integral tampons made from foamlike materials, i.e., nonaggregate
tampons, for example, a higher absorption rate, lower ejection
force from a tubular inserter, more rapid fluffing out, and greater
comfort both during wearing and during removal.
The characteristics and absorption performance of 1 .times. 1
.times. 2 inch rectangular parallelepipeds, i.e., solid blocks, and
rosettes of two different kinds of foamlike absorptive material in
a dynamic syngyna are shown in Table IV to illustrate the
advantages of operating within the defined limits of this
invention. The higher absorption rate for the aggregate tampon can
be noted by comparing the initial and overall absorption rate for
the aggregates versus the solid blocks. For example, in the
Hydro-Foam.sup.TM samples, the initial absorption rate went from
2.0 grams of syngyna fluid per minute for the solid block tampon to
25.4 grams of syngyna fluid per minute for the aggregate tampon,
and the overall rate went from 0.8 gram per minute to 15.4 grams
per minute when changing from the solid block tampon to an
aggregate tampon. This increase in the rate of absorption in the
aggregate tampons is unexpected and advantageous. A high absorption
rate is an important attribute of a tampon in order to prevent
partitioning failure which occurs when the rate of fluid flow to
the tampon exceeds the absorption rate of the tampon. In that
instance, the excess fluid flows past the tampon and down the
vaginal walls without being absorbed.
Another unexpected advantage of an aggregate tampon is that the
ejection force, i.e., the force required to eject a tampon from a
tubular inserter is lower than the ejection force for an equal
weight and approximately equal length integral tampon. The ejection
forces
TABLE IV - ABSORPTION PERFORMANCE OF AGGREGATE VS. SOLID TAMPONS
__________________________________________________________________________
Tampon Type Fluid* (Type) Overwrap (Reemay) Dry Weight of Sponge or
Foam (gm.) Dry Weight of Tampon (gm.) Weight of Fluid Absorbed
Initial Absorption Rate (gm./min.) Overall Absorption Rate
(gm./min.) Efficiency (gm. fluid/gm.
__________________________________________________________________________
tampon) Grecian Silk Sponge Solid Block S No 2.1 2.1 14.6 1.3 1.5
7.5 Aggregate S Yes 2.5 3.0 28.8 15.8 11.5 9.7 Aggregate C Yes 2.5
3.0 23.7 -- 2.4 8.0 Hydro-Foam.sup.TM Solid Block S No 2.3 2.3 25.4
2.0 0.8 10.8 Aggregate S Yes 2.5 3.0 23.6 25.4 15.4 8.0 Aggregate C
Yes 2.5 3.0 24.6 -- 1.9 8.2
__________________________________________________________________________
*S=Syngyna Fluid C=Citrated Blood
for four types of tampons, i.e., cut cones, rosettes, round sacks,
and solid cylinders are shown in Table V. The cut cones were made
by superposing two trapezoidal blanks, sewing the blanks together
along both sides and the short base, and inverting the sewed blanks
as more fully taught in the commonly owned, copending application
entitled HOLLOW FOAM TAMPONS FROM FLAT BLANKS, U.S. Ser. No.
353,058, filed Apr. 20, 1973. The rosettes were made as above
described for Example VIII except the amount of aggregate is
varied. The round sacks were made by taking a square of the
overwrap material, placing the aggregate in the middle of the
square, and enclosing the aggregate within the square by bringing
together the corners and edges of the square around the aggregate
into a neck which was fastened to prevent the square from opening.
The 1/8 inch scrim overwrap is a cotton gauze-type material wherein
the interfiber distance is about 1/8 inch in both directions and
the crossover points are not bonded. The cylinders were cut from a
block of the absorptive material. Table V includes tampons outside
the scope of this invention to illustrate the effect of operating
outside the limits of this invention.
The ejection force of an aggregate rosette tampon having a proper
packing factor is substantially less than the ejection force for a
cut cone of equal weight and absorbent material, even if the cut
cone is overwrapped with Reemay, the same as used for the rosette.
This is seen by comparing the ejection forces of the 21/2 gram cut
cone of Hydro-Foam.sup.TM with Reemay overwrap with the 21/2 grams
of Hydro-Foam.sup.TM rosette. In the
TABLE V - EJECTION FORCE FOR VARIOUS TYPES OF TAMPONS
______________________________________ EJECTION FORCE (lbs.)
______________________________________ Regular Inserter (ID=0.605
in.) Super Inserter (ID=0.71 in.) TAMPON* Static Dynamic Static
Dynamic ______________________________________ 2.5 g., cut cone,
H-F 13.0 9.6 4.1 3.5 2.5 g., cut cone, H-F, R-O 2.5 2.7 1.5 1.5 2.5
g., rosette, H-F, R-O 1.8 1.8 1.3 1.8 0.5 g., rosette, S, R-O 1.1
1.4 1.1 1.5 1.0 g., do. 2.9 2.9 2.4 2.0 1.5 g., do. 4.3 3.9 3.3 3.4
2.0 g., do. Inserters split while loading tampon 2.5 g., round
sack, H-F, R-O 3.0 3.1 1.7 1.7 2.5 g., round sack, H-F, S-O -- --
3.2 3.0 0.5 g., round sack, S, R-O 0.75 1.5 1.45 2.13 1.0 g., round
sack, S, R-O 2.9 3.2 3.27 3.45 1,5 g., round sack, S, S-O -- -- 1.8
2.5 1.0 g., 2 in. long cylinder, H-F 0.6 1.3 0.62 1.38 1.0 g., 2
in. long cylinder, S 6.3 7.3 4.4 4.7 0.5 g., 2 in. long cylinder,
S, R-O 1.0 1.6 0.5 1.0 1.0 g. do. 4.1 4.2 1.8 1.9
______________________________________ * H-F=Hydro-Foam.sup.TM as
absorbent material S=Grecian Silk Sponge as absorbent material
Rosette=Aggregate of pieces in structure of FIG. 3 R-O=Tampon had
Reemay overwrap S-O=Aggregate had 1/8-inch mesh scrim overwrap
regular inserter the static ejection force for the rosette was 1.8
pounds while the ejection force for the cut cone was 2.5 pounds;
and in the super inserter the static ejection force for the rosette
was 1.3 pounds while the cut cone took 1.5 pounds. It is also to be
noted from Table V that the rosette, which is a tubular aggregate
tampon, has a lower ejection force than a round aggregate tampon by
comparing the 21/2 grams of Hydro-Foam.sup.TM rosette with the 21/2
grams of Hydro-Foam.sup.TM round sack wherein the static ejection
force in the regular inserter for the rosette is only 1.8 pounds
while the static ejection force for the round sack in the same
inserter is 3.0 pounds. A similar decrease in ejection force for
the rosette versus the sack aggregate tampon is shown for the super
inserter.
Also unexpectedly in an aggregate tampon, the ejection force is
affected by the packing factor. Note tampons IV, V, and VI of Table
III have equal weights of foam therein and that the ejection force
increases as the packing factor decreases. Thus to obtain an
"optimum" packing factor, the effect of the packing factor on
absorption, comfort, and ejection force must all be considered.
The aggregate tampon of this invention also provides quicker dry
expansion from the temporal set imposed on the foamlike absorbent
materials such as are used in this invention while the absorbent
material is resiliently compressed within the tubular inserter. The
aggregate tampon fluffs out quicker than an integral tampon made of
the same absorbent material in that the aggregate regains its
unrestrained size after ejection from an inserter in a shorter time
period. This difference in temporal resiliency, i.e., the ability
of a tampon having a nonpermanent set to expand to its original
size, has been shown by placing several Hydro-Foam.sup.TM rosettes
made in the manner of Example VIII and several 2.5 gram
Hydro-Foam.sup.TM integral tampons, specifically cut cone tampons
without overwrap as described above, in two different conditions,
i.e., in a closed chamber suspended by the withdrawal string over
water at room temperature (75.degree. F.) so that the humidity in
the chamber approached 100 percent; and in vivo during nonmenstrual
times. Before the tampons were placed in either condition, they
were stored resiliently compacted within a tubular inserter having
an inside diameter of about 0.71 inch for over 21/2 months. The in
vivo tampons were withdrawn at predetermined intervals to determine
the percent of full expansion, i.e., expansion to the original
uncompacted size, which had occurred while the chambered tampons
were photographed at time intervals to record their expansion.
The tampon of this invention, i.e., the aggregate tampon, results
in greater wearing and removal comfort due to the capability for
relative motion between pieces 22 of the aggregate 24. The
aggregate tampon has essentially no tensile forces within the
absorbent body and therefore the absorbent body can more easily
conform itself to the vagina or the introital opening, whereas an
integral tampon does have tensile strength which holds it together
and prevents it from conforming as readily as the aggregate tampon.
The aggregate tampon lacking the structural integrity of an
integral tampon thus is somewhat amorphous and can more easily
change it shape to conform to its structural environment. The
amorphous character of a tampon of this invention can be controlled
by varying the amount of absorption material within the overwrap,
i.e., the packing factor. To achieve wearing and removal comfort,
the volume packing factor should be less than about 2.0 and
preferably less than about 1.38.
Also the aggregate tampon of this invention need not rely upon
tensile strength of the absorbent material to insure removal of the
entire tampon from the vagina after the tampon is used. In an
integral-type tampon, the tensile strength of the absorbent
material itself is relied on to remove the tampon from the vagina
because the withdrawal string is attached at only one or several
points on the absorbent body. In the aggregate tampon, the tensile
strength relied on for removal resides in the overwrap, and
therefore the tensile strength of the absorbent material is not a
critical parameter. It is desirable to eliminate tensile strength
as a requirement for the absorbent body because other desirable
properties of some absorbent materials such as polyurethane foams
are in inverse relationship to the tensile strength of the
material, i.e., when the absorption properties are bettered, the
tensile strength decreases. Thus it is advantageous to be able to
eliminate tensile strength of the absorbent material as a
requirement.
Thus it is apparent that there has been provided, in accordance
with the invention, a catamenial aggregate absorbent body that
fully satisfies the objects, aims, and advantages set forth above.
While the invention has been described in conjunction with specific
embodiments thereof, it is evident that many alternatives,
modifications, and variations will be apparent to those skilled in
the art in light of the foregoing description. Accordingly, it is
intended to embrace all such alternatives, modifications, and
variations as fall within the spirit and broad scope of the
appended claims.
* * * * *