U.S. patent application number 10/271008 was filed with the patent office on 2003-05-15 for multilayered apertured film wrapping element for absorbent articles.
Invention is credited to Johnson, Bruce C., Roller, Judith.
Application Number | 20030093049 10/271008 |
Document ID | / |
Family ID | 23353469 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030093049 |
Kind Code |
A1 |
Johnson, Bruce C. ; et
al. |
May 15, 2003 |
Multilayered apertured film wrapping element for absorbent
articles
Abstract
A multilayered apertured film wrapping element for an absorbent
article is disclosed. At least one outer layer of the
fluid-impervious plastic material has a continuous phase of a
thermoplastic polymeric component and an immiscible, dispersed
phase of a thermoplastic polymeric component having a lower melting
point. The wrapping element is useful in applications involving
heat sealing and similar thermal processes in absorbent articles,
such as sanitary napkins, diapers, bandages, tampons, and the
like.
Inventors: |
Johnson, Bruce C.; (Whiting,
NJ) ; Roller, Judith; (Brunswick, NJ) |
Correspondence
Address: |
AUDLEY A. CIAMPORCERO JR.
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
23353469 |
Appl. No.: |
10/271008 |
Filed: |
October 15, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10271008 |
Oct 15, 2002 |
|
|
|
09345090 |
Jun 30, 1999 |
|
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Current U.S.
Class: |
604/370 ;
604/378; 604/904 |
Current CPC
Class: |
A61F 13/2051 20130101;
A61F 13/512 20130101; Y10S 604/904 20130101 |
Class at
Publication: |
604/370 ;
604/378; 604/904 |
International
Class: |
A61F 013/15; A61F
013/20 |
Claims
What is claimed is:
1. A wrapping element useful in absorbent articles comprising
fluid-impervious plastic material in the form of a resilient
three-dimensional web exhibiting a fiber-like appearance and
tactile impression, the fluid-impervious plastic material comprises
a laminate having at least three layers: a) a first layer, forming
a first outer surface of the laminate, comprising a blend of at
least two thermoplastic polymeric components, a continuous phase of
a first thermoplastic polymeric component that exhibits a first
melting point temperature and a dispersed phase of an immiscible,
second thermoplastic polymeric component that exhibits a second
melting point temperature, less than the first melting point
temperature, such that when the web is heated to a temperature
between the first melting point temperature and the second melting
point temperature, the second thermoplastic polymeric component is
capable of forming an adhesive bond; b) a second layer forming a
second outer surface of the laminate, opposite the first outer
surface; and c) at least one intermediate layer, disposed between
the first and second layers, wherein the web has first and second
surfaces, the first surface being defined at least in part by the
either of the first and second layers and having a multiplicity of
apertures therein, each of the apertures being defined by a
multiplicity of intersecting fiber-like elements interconnected to
one another substantially in the plane of the first surface, each
of the fiber-like elements exhibiting a cross-section comprising a
base portion in the plane of the first surface and a sidewall
portion joined to each edge of the base portion, the sidewall
portions extending generally in the direction of the second surface
of the web, the intersecting sidewall portions being interconnected
to one another intermediate the first and the second surfaces of
the web, the interconnected sidewall portions terminating
substantially concurrently with one another in the plane of the
second surface.
2. The wrapping element of claim 1 wherein the first thermoplastic
polymeric component is selected from the group consisting of
polyolefins, polyesters, polyamides, polyurethanes, polystyrenes,
halogenated polymers, and copolymers thereof.
3. The wrapping element of claim 2 wherein the first thermoplastic
polymeric component comprises a polyolefin.
4. The wrapping element of claim 1 wherein the second thermoplastic
polymeric component is selected from the group consisting of
polyolefins, polyesters, polyamides, polyurethanes, polystyrenes,
halogenated polymers, and copolymers thereof.
5. The wrapping element of claim 4 wherein the second thermoplastic
polymeric component comprises a polyolefin.
6. The wrapping element of claim 1 wherein the difference between
the first melting point temperature and the second melting point
temperature is greater than about 20.degree. C.
7. The wrapping element of claim 1 wherein the first layer
comprises about 45 to about 95 wt-% of the thermoplastic polymeric
component and about 55 to about 5 wt-% of the second thermoplastic
polymeric component.
8. The wrapping element of claim 7 wherein the first layer
comprises about 60 to about 80 wt-% of the thermoplastic polymeric
component and about 40 to about 20 wt-% of the second thermoplastic
polymeric component.
9. The wrapping element of claim 1 wherein the first layer further
comprises one or more components selected from the group comprising
antioxidants, UV absorbers, lubricants, antiblock agents, slip
agents, plasticizers, nucleating agents, antistatic agents, flame
retardants, pigments, dyes, and fillers.
10. The wrapping element of claim 1 wherein the second layer
comprises a component selected from the group consisting of
polyolefins, polyesters, polyamides, polyurethanes, polystyrenes,
halogenated polymers, and copolymers thereof.
11. The wrapping element of claim 1 wherein the second layer
comprises a blend of at least two thermoplastic polymeric
components, a continuous phase of a first thermoplastic polymeric
component that exhibits a first melting point temperature and a
dispersed phase of an immiscible, second thermoplastic polymeric
component that exhibits a second melting point temperature, less
than the first melting point temperature, such that when the web is
heated to a temperature between the first melting point temperature
and the second melting point temperature, the second thermoplastic
polymeric component is capable of forming an adhesive bond;
12. The wrapping element of claim 11 wherein the first
thermoplastic polymeric component of the second layer is selected
from the group consisting of polyolefins, polyesters, polyamides,
polyurethanes, polystyrenes, halogenated polymers, and copolymers
thereof.
13. The wrapping element of claim 12 wherein the first
thermoplastic polymeric of the second layer component comprises a
polyolefin.
14. The wrapping element of claim 11 wherein the second
thermoplastic polymeric component of the second layer is selected
from the group consisting of polyolefins, polyesters, polyamides,
polyurethanes, polystyrenes, halogenated polymers, and copolymers
thereof.
15. The wrapping element of claim 14 wherein the second
thermoplastic polymeric component of the second layer comprises a
polyolefin.
16. The wrapping element of claim 11 wherein the difference between
the first melting point temperature and the second melting point
temperature of the components of the second layer is greater than
about 20.degree. C.
17. The wrapping element of claim 11 wherein the second layer
comprises about 45 to about 95 wt-% of the thermoplastic polymeric
component and about 55 to about 5 wt-% of the second thermoplastic
polymeric component.
18. The wrapping element of claim 17 wherein the second layer
comprises about 60 to about 80 wt-% of the thermoplastic polymeric
component and about 40 to about 20 wt-% of the second thermoplastic
polymeric component.
19. The wrapping element of claim 11 wherein the first and second
layers are substantially identical.
20. The wrapping element of claim 1 wherein the intermediate layer
comprises a component selected from the group consisting of
polyolefins, polyesters, polyamides, polyurethanes, polystyrenes,
halogenated polymers, and copolymers thereof.
21. The wrapping element of claim 20 wherein the intermediate layer
comprises a polyolefin or a polyolefin copolymer.
22. The wrapping element of claim 21 wherein the intermediate layer
comprises a blend of polyethylene and ethylene-vinyl acetate
copolymer.
23. The wrapping element of claim 1 wherein the intermediate layer
further comprises one or more components selected from the group
comprising antioxidants, UV absorbers, lubricants, antiblock
agents, slip agents, plasticizers, nucleating agents, antistatic
agents, flame retardants, pigments, dyes, and fillers.
24. The wrapping element of claim 23 wherein the intermediate layer
comprises greater than about 5 wt-% of a pigment.
25. The wrapping element of claim 1 wherein the intermediate layer
comprises a blend of polymeric materials.
26. The wrapping element of claim 25 wherein the intermediate layer
comprises a blend of about 45 to about 99 wt-% of a first polymeric
component and about 1 to about 55 wt-% of a second polymeric
component.
27. The wrapping element of claim 1 which further comprises an
additional intermediate layer.
28. The wrapping element of claim 1 wherein the first surface of
the web is defined, at least in part, by the first layer of the
laminate.
29. A tampon comprising an absorbent structure substantially
enclosed by a cover wherein: (1) the cover comprises
fluid-impervious plastic material in the form of a resilient
three-dimensional web exhibiting a fiber-like appearance and
tactile impression, (2) the fluid-impervious plastic material
comprises a laminate having at least three layers: a first layer,
forming a first outer surface of the laminate, comprising a blend
of at least two thermoplastic polymeric components, a continuous
phase of a first thermoplastic polymeric component that exhibits a
first melting point temperature and a dispersed phase of an
immiscible, second thermoplastic polymeric component that exhibits
a second melting point temperature, less than the first melting
point temperature, such that when the web is heated to a
temperature between the first melting point temperature and the
second melting point temperature, the second thermoplastic
polymeric component is capable of forming an adhesive bond; a
second layer forming a second outer surface of the laminate,
opposite the first outer surface; and at least one intermediate
layer, disposed between the first and second layers; and (3) the
web has first and second surfaces, the first surface being defined
at least in part by the first layer and having a multiplicity of
apertures therein, each of the apertures being defined by a
multiplicity of intersecting fiber-like elements interconnected to
one another substantially in the plane of the first surface, each
of the fiber-like elements exhibiting a cross-section comprising a
base portion in the plane of the first surface and a sidewall
portion joined to each edge of the base portion, the sidewall
portions extending generally in the direction of the second surface
of the web, the intersecting sidewall portions being interconnected
to one another intermediate the first and the second surfaces of
the web, the interconnected sidewall portions terminating
substantially concurrently with one another in the plane of the
second surface.
30. The tampon of claim 29 wherein the first thermoplastic
polymeric component is selected from the group consisting of
polyolefins, polyesters, polyamides, polyurethanes, polystyrenes,
halogenated polymers, and copolymers thereof.
31. The tampon of claim 30 wherein the first thermoplastic
polymeric component comprises a polyolefin.
32. The tampon of claim 29 wherein the second thermoplastic
polymeric component is selected from the group consisting of
polyolefins, polyesters, polyamides, polyurethanes, polystyrenes,
halogenated polymers, and copolymers thereof.
33. The tampon of claim 32 wherein the second thermoplastic
polymeric component comprises a polyolefin. polyesters, polyamides,
polyurethanes, polystyrenes, halogenated polymers, and copolymers
thereof.
38. The tampon of claim 37 wherein the first thermoplastic
polymeric of the second layer component comprises a polyolefin.
39. The tampon of claim 36 wherein the second thermoplastic
polymeric component of the second layer is selected from the group
consisting of polyolefins, polyesters, polyamides, polyurethanes,
polystyrenes, halogenated polymers, and copolymers thereof.
40. The tampon of claim 39 wherein the second thermoplastic
polymeric component of the second layer comprises a polyolefin.
41. The tampon of claim 36 wherein the difference between the first
melting point temperature and the second melting point temperature
of the components of the second layer is greater than about
20.degree. C.
42. The tampon of claim 36 wherein the second layer comprises about
45 to about 95 wt-% of the thermoplastic polymeric component and
about 55 to about 5 wt-% of the second thermoplastic polymeric
component.
43. The tampon of claim 36 wherein the first and second layers are
substantially identical.
44. The tampon of claim 29 wherein the intermediate layer comprises
a component selected from the group consisting of polyolefins,
polyesters, polyamides, polyurethanes, polystyrenes, halogenated
polymers, and copolymers thereof.
45. The tampon of claim 44 wherein the intermediate layer comprises
a polyolefin or a polyolefin copolymer.
46. The tampon of claim 45 wherein the intermediate layer comprises
a blend of polyethylene and ethylene-vinyl acetate copolymer.
47. The tampon of claim 29 wherein the intermediate layer further
comprises one or more components selected from the group comprising
antioxidants, UV absorbers, lubricants, antiblock agents, slip
agents, plasticizers, nucleating agents, antistatic agents, flame
retardants, pigments, dyes, and fillers.
48. The tampon of claim 47 wherein the intermediate layer comprises
greater than about 5 wt-% of a pigment.
49. The tampon of claim 29 wherein the intermediate layer comprises
a blend of polymeric materials.
50. The tampon of claim 49 wherein the intermediate layer comprises
a blend of about 45 to about 99 wt-% of a first polymeric component
and about 1 to about 55 wt-% of a second polymeric component.
51. The tampon of claim 29 which further comprises an additional
intermediate layer.
52. A method of forming a wrapping element useful in absorbent
articles, comprising the steps of: forming a laminate having at
least three layers having a first layer, forming a first outer
surface of the laminate, comprising a blend of at least two
thermoplastic polymeric components, a continuous phase of a first
thermoplastic polymeric component that exhibits a first melting
point temperature and a dispersed phase of an immiscible, second
thermoplastic polymeric component that exhibits a second melting
point temperature, less than the first melting point temperature,
such that when the web is heated to a temperature between the first
melting point temperature and the second melting point temperature,
the second thermoplastic polymeric component is capable of forming
an adhesive bond; a second layer forming a second outer surface of
the laminate, opposite the first outer surface; and at least one
intermediate layer, disposed between the first and second layers;
applying fluid at a temperature greater than ambient temperature to
the laminate while it is supported on a three-dimensional surface
to form a resilient three-dimensional web exhibiting a fiber-like
appearance and tactile impression, wherein the web has first and
second surfaces, the first surface being defined at least in part
by the either of the first and second layers and having a
multiplicity of apertures therein, each of the apertures being
defined by a multiplicity of intersecting fiber-like elements
interconnected to one another substantially in the plane of the
first surface, each of the fiber-like elements exhibiting a
cross-section comprising a base portion in the plane of the first
surface and a sidewall portion joined to each edge of the base
portion, the sidewall portions extending generally in the direction
of the second surface of the web, the intersecting sidewall
portions being interconnected to one another intermediate the first
and the second surfaces of the web, the interconnected sidewall
portions terminating substantially concurrently with one another in
the plane of the second surface.-dimensional web exhibiting a
fiber-like appearance and tactile impression; and separating the
web into individual pieces of material of a size appropriate for a
wrapping element.
53. The method of claim 52 wherein the step of forming the laminate
comprises extruding thermoplastic polymeric components through an
extruder.
54. The method of claim 53 wherein the first and second layers are
extruded together to envelope the intermediate layer.
55. A method of making a tampon comprising the steps of: separating
a cover from a supply of a resilient three-dimensional web
exhibiting a fiber-like appearance and tactile impression, the web
comprising fluid-impervious plastic material which comprises a
laminate having at least three layers: a first layer, forming a
first outer surface of the laminate, comprising a blend of at least
two thermoplastic polymeric components, a continuous phase of a
first thermoplastic polymeric component that exhibits a first
melting point temperature and a dispersed phase of an immiscible,
second thermoplastic polymeric component that exhibits a second
melting point temperature, less than the first melting point
temperature, such that when the web is heated to a temperature
between the first melting point temperature and the second melting
point temperature, the second thermoplastic polymeric component is
capable of forming an adhesive bond; a second layer forming a
second outer surface of the laminate, opposite the first outer
surface, comprising a blend of at least two thermoplastic polymeric
components, a continuous phase of a first thermoplastic polymeric
component that exhibits a first melting point temperature and a
dispersed phase of an immiscible, second thermoplastic polymeric
component that exhibits a second melting point temperature, less
than the first melting point temperature, such that when the web is
heated to a temperature between the first melting point temperature
and the second melting point temperature, the second thermoplastic
polymeric component is capable of forming an adhesive bond; and at
least one intermediate layer, disposed between the first and second
layers; and the web has first and second surfaces, the first
surface being defined at least in part by the first layer and
having a multiplicity of apertures therein, each of the apertures
being defined by a multiplicity of intersecting fiber-like elements
interconnected to one another substantially in the plane of the
first surface, each of the fiber-like elements exhibiting a
cross-section comprising a base portion in the plane of the first
surface and a sidewall portion joined to each edge of the base
portion, the sidewall portions extending generally in the direction
of the second surface of the web, the intersecting sidewall
portions being interconnected to one another intermediate the first
and the second surfaces of the web, the interconnected sidewall
portions terminating substantially concurrently with one another in
the plane of the second surface; substantially enclosing an
absorbent structure with the cover; and applying thermal energy to
the cover to heat it to a temperature between the first melting
point temperature and the second melting point temperature of the
first layer to form an adhesive bond.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This invention is related to the following copending
applications: U.S. Ser. No. ______, filed Jun. ______, 1999,
entitled "Continuous Method of Providing Individual Sheets from a
Continuous Web" (Attorney Docket, PPC-668); U.S. Ser. No. ______,
filed Jun. ______, 1999, entitled "Tampon with Cover and Nonionic
Surfactant" (Attorney Docket, PPC-708); U.S. Ser. No. ______, filed
Jun. ______, 1999, entitled "Heterogeneous Apertured Film Wrapping
Element for Absorbent Articles" (Attorney Docket, PPC-713); U.S.
Ser. No. ______, filed Jun. ______, 1999, entitled "Domed Tampon
with Surfactant-Treated Cover" (Attorney Docket, J&J-1810);
U.S. Ser. No. ______, filed Jun. ______, 1999, entitled "Sealing
Roller and Sealing Roller Element, Particularly for Producing a
Tampon for Feminine Hygiene and Method Therefore" (Attorney Docket,
J&J-1819); and U.S. Ser. No. ______, filed Jun. ______, 1999,
entitled "Tampon for Feminine Hygiene and Process and Apparatus for
its Production" (Attorney Docket, J&J-1820).
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a multilayered apertured
film wrapping element for an absorbent article. At least one outer
layer of the fluid-impervious plastic material has a continuous
phase of a thermoplastic polymeric component and an immiscible,
dispersed phase of a thermoplastic polymeric component having a
lower melting point. The wrapping element is useful in applications
involving heat sealing and similar thermal processes in absorbent
articles, such as sanitary napkins, diapers, bandages, tampons, and
the like.
[0003] There are several types of wrapping elements, including
covers, that have been or are currently in use for absorbent
articles: woven fabrics, nonwoven fabrics, apertured films,
reticulated films, polymer nets, and the like. There has been a
progression from woven fabrics to nonwoven fabrics and apertured
films in these covers. These covers are often adhesively attached
to other components in the absorbent article. An adhesive may be
applied as a separate component between the cover and another
component, or adhesion may result from "heat sealing" or heating
one of the components to cause it to become adhesive.
[0004] Nonwoven fabrics may incorporate multicomponent fibers
having at least two different melting points. Then these fabrics
may be adhered to an absorbent article, such as a tampon, as
described in Friese, U.S. Pat. Nos. 4,816,100; 4,836,450; and
4,859,273. This is one example of heat sealing a wrapping element
or cover.
[0005] It may also be desirable to heat seal an apertured film.
While it may be possible to heat seal an apertured film that is
formed of only one component, this is generally only in areas where
it is acceptable or even desirable that the apertures in the film
become closed. However, heat sealing an apertured film to an
underlying fibrous structure in a manner that maintains open
apertures in the heat sealing area is more complex, and it
generally requires the use of a film material having at least two
different components having at least two different melting point
temperatures. An example of this is described in Thompson et al.,
U.S. Pat. No. 5,342,334. In this example, the apertured film is
formed from a co-extruded film having a higher melting point
polymeric material on a first, non-bonded surface, and a lower
melting point polymeric material on a second, heat-bondable
surface. Unfortunately, this arrangement provides a large surface
area of bondable material on the second surface, and it may allow
unwanted or overly aggressive adhesion in the manufacturing process
or final product. The film may adhere to process equipment, such as
the apertured film forming surfaces and heat sealing elements. In
addition, both layers of the film are exposed to process
equipment.
[0006] Therefore, what is needed is an apertured film that is heat
sealable in a controlled manner, that maintains open apertures,
that separates at least one intermediate layer of the film from
process equipment to protect both the layer and the equipment from
damage, and that allows improved balance of film properties over a
monolayer or bilayer film.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a wrapping element useful
in absorbent articles. The wrapping element is formed of a
fluid-impervious plastic material in the form of a resilient
three-dimensional web exhibiting a fiber-like appearance and
tactile impression. The fluid-impervious plastic material is formed
of a laminate having at least three layers: a first layer, forming
a first outer surface of the laminate; a second layer forming a
second outer surface of the laminate, opposite the first outer
surface; and at least one intermediate layer, disposed between the
first and second layers. The first layer has a blend of at least
two thermoplastic polymeric components, a continuous phase of a
first thermoplastic polymeric component that exhibits a first
melting point temperature and a dispersed phase of an immiscible,
second thermoplastic polymeric component that exhibits a second
melting point temperature, less than the first melting point
temperature. Therefore, that when the web is heated to a
temperature between the first melting point temperature and the
second melting point temperature, the second thermoplastic
polymeric component is capable of forming an adhesive bond. The web
has first and second surfaces. The first surface is defined at
least in part by the either of the first and second layers, and it
has a multiplicity of apertures therein. The apertures are defined
by a multiplicity of intersecting fiber-like elements
interconnected to one another substantially in the plane of the
first surface. Each of the fiber-like elements exhibits a
cross-section having a base portion in the plane of the first
surface and a sidewall portion joined to each edge of the base
portion. The sidewall portions extend generally in the direction of
the second surface of the web, and the intersecting sidewall
portions are interconnected to one another intermediate the first
and the second surfaces of the web. The interconnected sidewall
portions terminate substantially concurrently with one another in
the plane of the second surface. In another aspect, the invention
relates to a tampon having an absorbent structure substantially
enclosed by the wrapping element.
[0008] The invention also relates to a method of forming a wrapping
element useful in absorbent articles. The method includes the steps
of forming a laminate having at least three layers, applying fluid
at a temperature greater than ambient temperature to the laminate
while it is supported on a three-dimensional surface to form a
resilient three-dimensional web, and separating the web into
individual pieces of material of a size appropriate for a wrapping
element.
[0009] Again, the web has first and second surfaces, and the first
surface is defined at least in part by the either of the first and
second layers and having a multiplicity of apertures therein. Each
of the apertures is defined by a multiplicity of intersecting
fiber-like elements interconnected to one another substantially in
the plane of the first surface, and each of the fiber-like elements
exhibits a cross-section comprising a base portion in the plane of
the first surface and a sidewall portion joined to each edge of the
base portion. The sidewall portions extend generally in the
direction of the second surface of the web, and the intersecting
sidewall portions are interconnected to one another intermediate
the first and the second surfaces of the web. The interconnected
sidewall portions terminate substantially concurrently with one
another in the plane of the second surface. The laminate is
substantially as described above.
[0010] Finally, the invention also relates to a method of making a
tampon. The method includes separating a cover from a supply of a
resilient three-dimensional web such as that described above,
substantially enclosing an absorbent structure with the cover, and
applying thermal energy to the cover to heat it to a temperature
between the first melting point temperature and the second melting
point temperature of the first layer to form an adhesive bond.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 is a tampon having an apertured film cover according
to the present invention.
[0012] FIG. 2 is an enlarged cross-section of an apertured film
according to the present invention.
[0013] FIG. 3 is an enlarged cross-section of an alternative
embodiment of the apertured film of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] As used herein, the term "absorbent article" refers to
devices that absorb and contain body exudates and that are worn on
or inside the body. These devices preferably absorb and contain
blood, urine, and/or vaginal discharges, such as bandages, dental
and nasal tampons, diapers, sanitary napkins, incontinence guards
or pads, interlabial sanitary protection devices, and internal
sanitary protection devices such as tampons.
[0015] As used herein, the term "apertured film" refers to a
fluid-impervious plastic material in the form of a resilient
three-dimensional web having first and second surfaces and
exhibiting a fiber-like appearance and tactile impression. The
first surface of the three-dimensional web has a multiplicity of
apertures therein. Preferably, each of the apertures is defined by
a multiplicity of intersecting, fiber-like elements interconnected
to one another substantially in the plane of the first surface.
Each of the fiber-like elements exhibits a cross-section,
preferably having a base portion in the plane of the first surface
and a sidewall joined to each edge of the base portion. The
sidewall portions extend generally in the direction of the second
surface of the three-dimensional web. Further, the intersecting
sidewall portions are interconnected to one another intermediate
the first and second surfaces of the web. The interconnected
sidewall portions preferably terminate substantially concurrently
with one another in the plane of the second surface.
[0016] As used herein, the term "wrapping element" refers to an
element of an absorbent article that, alone or in conjunction with
one or more additional element(s), substantially encloses an
absorbent structure. As used herein, the term "cover" refers to a
wrapping element located on the outer surface of an absorbent
article.
[0017] The absorbent articles of the present invention, e.g., a
tampon 10, comprise an apertured film wrapping element, e.g., a
cover 12, and an absorbent structure 14. The wrapping element at
least partially encloses the absorbent structure that is generally
designed and constructed to absorb and contain bodily exudates
[0018] As indicated above, the presence of the sidewalls 16 between
the first surface 18 and second surface 20 of the web imparts a
generally three-dimensional quality to the wrapping element. This
three-dimensional quality is distinct from the generally
two-dimensional quality of a reticulated film, such as that
described in U.S. Pat. No. 4,710,186, the disclosure of which is
hereby incorporated by reference. Two-dimensional reticulated films
more readily allow portions of the absorbent materials of the
absorbent structure to protrude through to the surface of the
absorbent article, such as a tampon.
[0019] The three-dimensional quality provided by the sidewalls 16
helps to separate the absorbent materials of the absorbent
structure 14 from the surface of the absorbent article, often
defined by the first surface 18 of the wrapping element 12. The
longer the sidewalls 16, the greater the separation of the
absorbent structure materials from the article surface and the less
likely it is that any absorbent structure materials will protrude
through the openings 22 in the apertured film 12 to contact the
user's body tissues during use.
[0020] Some types of absorbent materials may protrude more easily
through the openings 22 in the apertured film 12, and thus, longer
sidewalls 16 may be needed to prevent protrusion. It will be
recognized by those familiar in the art that tampons 10 are often
compressed during the manufacturing process. Such compression may
cause the sidewalls 16 of the apertured film 12 to fold over. Such
folding, however, does not appear to detract from the ability of
the sidewalls 16 to prevent protrusion of the absorbent materials
through the openings 22 in the apertured film 12.
[0021] FIG. 2 is an enlarged cross-section of a wrapping element,
e.g., cover 12, according to the present invention. The wrapping
element is a web having first surface 18 and second surface 20. As
can be seen in this figure, the web is preferably comprised of a
laminate having a plurality of layers: a first layer 24, a second
layer 26, and an intermediate layer 28 disposed therebetween.
Although only one intermediate layer 28 is illustrated in this FIG.
2, it will be apparent to one of ordinary skill that additional
intermediate layers (e.g., second intermediate layer 28A in FIG. 3)
may also be added.
[0022] The first layer forms a first outer surface of the laminate.
This layer is formed of a blend of at least two thermoplastic
polymeric components. The first thermoplastic polymeric component
forms a continuous phase that exhibits a first melting point
temperature. In order to form the continuous phase, it is preferred
that the first thermoplastic polymeric component be present at
about 45 to about 95 wt-% of the layer, more preferably about 60 to
about 80 wt-% of the layer. A dispersed phase comprises a second
thermoplastic polymeric component that exhibits a second melting
point temperature. It is preferred that the second thermoplastic
polymeric component is present at about 55 to about 5 wt-% of the
layer, more preferably about 40 to about 20 wt-% of the layer. In
addition, the second melting point temperature is sufficiently less
than the first melting point temperature to allow the film to be
heated to a temperature between the first and second melting point
temperatures, rendering the second thermoplastic polymeric
component capable of forming an adhesive bond. This bond may be
formed between different portions of the wrapping element, or it
may be between the wrapping element and another element of the
absorbent article. Preferably, the difference between the first
melting point temperature and the second melting point temperature
is greater than about 20.degree. C., and more preferably, the
difference between the first melting point temperature is greater
than about 30.degree. C. Most preferably, the difference is greater
than about 40.degree. C.
[0023] The continuous phase provides the "backbone" of the layer
and contributes most of the layer's mechanical properties, such as
tensile strength, stiffness, elongation at break, coefficient of
friction, modulus, and the like. The first thermoplastic polymeric
component substantially provides these properties. Therefore, the
first thermoplastic polymeric component of the first layer will be
chosen for its desirable properties. A representative, non-limiting
list of suitable polymers for the first thermoplastic polymeric
component includes polyolefins, such as polypropylene and
polyethylene; polyolefin copolymers, such as ethylene-vinyl acetate
("EVA"), ethylene-propylene, ethylene-acrylates, and
ethylene-acrylic acid and salts thereof; halogenated polymers;
polyesters and polyester copolymers; polyamides and polyamide
copolymers; polyurethanes and polyurethane copolymers; polystyrenes
and polystyrene copolymers; and the like. Preferred first
thermoplastic polymeric components include polyolefins, especially
polypropylene.
[0024] The dispersed phase provides localized areas for thermal
bonding to adjacent elements. The second thermoplastic polymeric
component provides these properties, and it may also contribute to
some of the mechanical properties, including coefficient of
friction. A representative, non-limiting list of suitable polymers
for the second thermoplastic polymeric component includes
polyolefins, such as polypropylene and polyethylene; polyolefin
copolymers, such as ethylene-vinyl acetate ("EVA"),
ethylene-propylene, ethylene-acrylates, and ethylene-acrylic acid
and salts thereof; halogenated polymers; polyesters and polyester
copolymers; polyamides and polyamide copolymers; polyurethanes and
polyurethane copolymers; polystyrenes and polystyrene copolymers;
and the like. Preferred second thermoplastic polymeric components
include polyethylene and its copolymers, especially linear low
density polyethylene (LLDPE), low density polyethylene (LDPE) and
EVA.
[0025] The first and second thermoplastic polymeric components of
the first layer should be selected to allow the desired properties
of each material to be apparent. For example, a combination of
polypropylene (continuous phase) and polyethylene (dispersed phase)
employs thermoplastic polymeric components that have a viable
melting point differential to allow for heat sealing and that are
compatible, e.g., they can be extruded from the same extrusion head
without charring, etc. In contrast, a combination of LLDPE
(continuous phase) and LDPE (dispersed phase) would be less
desirable, because there is insufficient melting point differential
to provide for acceptable heat sealing. Additionally, a combination
of nylon-6 (continuous phase) and EVA (dispersed phase) would also
be less desirable as the dispersed phase is likely to be degraded
in a film extrusion process.
[0026] In addition, other components and further additives can be
added to the first layer in an amount that will not hinder
obtaining the object of the present invention, including, without
limitation, antioxidants, UV absorbers, lubricants, antiblock and
slip agents, plasticizers, nucleating agents, antistatic agents,
flame retardants, pigments, dyes, and inorganic or organic
fillers.
[0027] The second layer forms a second outer surface of the
laminate, opposite the first outer surface. This layer may have
fewer restrictions than the first layer. It may have only one
component, or it may also be a blend of at least two components. If
a blend is chosen, it may be homogeneous, or it may be a blend of
at least two immiscible polymeric materials. A representative,
non-limiting list of suitable polymers for the second layer
includes polyolefins, such as polypropylene and polyethylene;
polyolefin copolymers, such as ethylene-vinyl acetate ("EVA"),
ethylene-propylene, ethylene-acrylates, and ethylene-acrylic acid
and salts thereof; halogenated polymers; polyesters and polyester
copolymers; polyamides and polyamide copolymers; polyurethanes and
polyurethane copolymers; polystyrenes and polystyrene copolymers;
and the like; or combinations thereof. However, the second layer
may also include other polymers, including a discrete phase
comprising thermoset polymers.
[0028] In addition, other components and further additives can be
added to the second layer in an amount that will not hinder
obtaining the object of the present invention, including, without
limitation, antioxidants, UV absorbers, lubricants, antiblock and
slip agents, plasticizers, nucleating agents, antistatic agents,
flame retardants, pigments, dyes, and inorganic or organic
fillers.
[0029] In a preferred embodiment, the second layer of the wrapping
element has the characteristics described above for the first
layer. It may be the same as or different than the first layer.
Preferably, the first and second layers are substantially identical
to enable a single extruder to form both layers.
[0030] At least one intermediate layer is disposed between the
first and second layers to contribute additional, desirable
properties to the wrapping element. For example, the at least one
intermediate layer (otherwise described as "intermediate layer(s)")
may have an elevated loading of pigment to increase the opacity of
the wrapping element. If pigments are loaded in a monolayered film
at levels that are too high, the additives may "plate out" of the
film, creating poorer appearance and clogging and/or abrading
processing equipment. However, elevated loading of pigments in an
intermediate layer is less likely to cause the same extent of the
problems likely caused if this loading exists in an outer layer or
monolayer. Therefore, it is possible to have pigment loading in
excess of 10 wt-% in the intermediate layer, preferably, about 1 to
about 10 wt-%, and most preferably, about 8 to about 10 wt-%
pigment in the intermediate layer. This pigment loading, in
combination with some pigment loading in the first and/or second
layers may result in films having a pigment loading in excess of
about 5 wt-%, preferably, about 5 to about 8 wt-%, and most
preferably, an overall pigment loading in the film of about 6 to
about 7 wt-%.
[0031] In addition, the intermediate layer(s) may comprise
polymeric materials that are softer, tackier, more ductile, and
have a lower modulus, etc., than the materials in the outer two
layers. This can result in a wrapping element that has improved
softness and drape. In contrast, using the same polymeric materials
in a monolayer film may increase the likelihood that the film will
stick to process equipment surfaces or to itself, may increase the
tackiness of the film, or may cause the film to be too limp. It may
also reduce the ability of the film to form the desired
apertures.
[0032] Further, the intermediate layer(s) may comprise polymeric
materials that are stiffer, than the materials in the outer two
layers. This can result in a more defined apertured web that better
maintains its three-dimensional characteristics. Again, using these
polymeric materials in a monolayer film may reduce the tendency of
the aperturing process to form desirable apertures. Other useful
variations in the intermediate layer(s) will be apparent to those
of ordinary skill in the art.
[0033] The intermediate layer(s) may be formed of a single
thermoplastic polymeric material, or it may be formed of at least
one blend of at least two immiscible polymeric materials. A
representative, non-limiting list of polymeric materials that may
be used in the intermediate layer(s) includes polyolefins, such as
polypropylene and polyethylene; polyolefin copolymers, such as
ethylene-vinyl acetate ("EVA"), ethylene-propylene,
ethylene-acrylates, and ethylene-acrylic acid and salts thereof;
halogenated polymers; polyesters and polyester copolymers;
polyamides and polyamide copolymers; polyurethanes and polyurethane
copolymers; polystyrenes and polystyrene copolymers; and the like.
Preferred intermediate layer polymeric materials include
polyolefins, especially polypropylene, and ethylene copolymers,
especially EVA.
[0034] If the intermediate layer(s) is formed of a blend, it is
preferred that the first thermoplastic polymeric component of the
intermediate layer(s) represents about 45 to about 99 wt-% of the
film and forms a continuous phase. One or more additional polymeric
materials of the intermediate layer(s) may then form one or more
dispersed phase within the continuous phase. Again, the first and
second thermoplastic polymeric components of a blended intermediate
layer should be selected to allow the desired properties of each
material to be apparent.
[0035] Again, other components and further additives can be added
to the intermediate layer(s) in an amount that will not hinder
obtaining the object of the present invention, including, without
limitation, antioxidants, UV absorbers, lubricants, antiblock and
slip agents, plasticizers, nucleating agents, antistatic agents,
flame retardants, pigments, dyes, and inorganic or organic
fillers.
[0036] It is also necessary to use care in selecting the
appropriate individual layers of the laminate. They should be
selected to provide appropriate laminate integrity. This integrity
relates to effectiveness during heat sealing, resistance to
degradation under processing conditions, etc. For example, the
following combinations of laminate layers have been found to be
acceptable: Polypropylene/polyethylene (first and second layers)
with polyethylene/EVA (intermediate layer) and LLDPE/LDPE (first
and second layers) with LDPE/high density polyethylene ("HDPE")
(intermediate layer). In contrast, a combination of nylon-6 and
HDPE would be less desirable, because the laminate layers are
likely to separate.
[0037] The absorbent structure may be any absorbent means that is
capable of absorbing and/or retaining liquids (e.g., menses and/or
urine). The absorbent structure can be manufactured in a wide
variety of sizes and shapes and from a wide variety of
liquid-absorbing materials. A representative, non-limiting list of
useful materials includes cellulosic materials, such as rayon,
cotton, wood pulp, creped cellulose wadding, tissue wraps and
laminates, peat moss, and chemically stiffened, modified, or
cross-linked cellulosic fibers; synthetic materials, such as
polyester fibers, polyolefin fibers, absorbent foams, absorbent
sponges, superabsorbent polymers, absorbent gelling materials;
formed fibers, such as capillary channel fibers and multilimbed
fibers; combinations of materials, such as synthetic fibers and
wood pulp including coformed fibrous structures (e.g., those
materials described in Anderson et al., U.S. Pat. No. 4,100,324);
or any equivalent material or combinations of materials, or
mixtures of these.
[0038] The wrapping element of the present invention can be
manufactured by standard processes known to those of ordinary skill
in the art. For example, the base film that is to be apertured can
be extruded through multiple extruders to form the three-layered
co-extruded film. Additional extruder heads may be added to form
additional layers in the laminated film. This technology is well
known to those of ordinary skill in the art. The base film can then
be apertured by any of the known processes. Several examples
include hot air aperturing, and water jet aperturing. Examples of
these process are disclosed in Curro, U.S. Pat. No. 4,695,422;
Turi, U.S. Pat. No. 5,567,376; and Mullane, U.S. Pat. No.
4,741,877. The resulting multilayered apertured film can be coated,
for example as described in commonly assigned, co-pending U.S.
application Ser. No.______, filed Jun. ______, 1999, entitled
"Tampon with Cover and Nonionic Surfactant" (Attorney Docket
PPC-708), and/or slit to a desired width for use in manufacturing
an absorbent
[0039] A preferred embodiment of the present invention is a tampon
10 having an apertured film cover 12 substantially enclosing an
absorbent structure 14. The cover 12 is useful to contain the
absorbent structure materials to reduce, preferably prevent, the
likelihood that any significant portion of the absorbent structure
14 will escape from the tampon 10 and remain after the tampon 10
has been removed, e.g., by pulling on the withdrawal string 30. The
cover 12 can also protect the tissue in contact with the tampon 10
from excessive friction or other irritation during insertion, use,
and removal of the tampon 10. Further, the cover 12 can add
aesthetic qualities to the tampon 10. Therefore, it is desirable
that the cover 12 have the following properties low coefficient of
friction, smooth surface, high opacity, clear apertures, and
unmelted appearance.
[0040] In addition, because the cover 12 contains the absorbent
structure 14, and because it is often desirable that the cover 12
and absorbent structure 14 be secured to each other, the cover 12
should be capable is of thermally bonding at least to itself in a
manner that secures the absorbent structure 14 within it.
Preferably, the cover 12 is also capable of thermally bonding to
the outer portions of the absorbent structure 14, itself. These
thermal bonding processes
[0041] One method of applying the apertured film cover material to
an absorbent structure in the manufacture of a tampon is the use of
a cut-and-place unit to cut the material from the slit roll and to
place it on the absorbent structure. Another method is generally
described in Friese, U.S. Pat. No. 4,816,100, the disclosure of
which is herein incorporated by reference. While this describes the
use of a nonwoven cover to a tampon, improvements necessary to
achieve this are described in the commonly-assigned, copending
application, U.S. Ser. No., filed Jun. ______ 1999, entitled
"Continuous Method of Providing Individual Sheets from a Continuous
Web" (Attorney Docket PPC-668), the disclosure of which is herein
incorporated by reference. This copending application discloses a
method to achieve the total separation of a section of material
comprises the following steps: severing a supply material in a
plurality of discrete regions along a transverse axis, scoring the
material residing between the severed regions along the same
transverse axis, and then applying a force sufficient to fracture
the scored regions, thereby separating the section of material from
its supply.
[0042] It is in the latter process that the present invention is
particularly useful. In this process, an intermediate layer
comprising a relatively low modulus or low ductility material can
reduce uncontrolled movement of the cover material as it is
perforated, scored, and stretched to form a separated segment of
cover material. Particularly desirable cover material that is
useful in such a process is one that incorporates a low modulus
polymeric material in the intermediate layer(s). A representative,
non-limiting list of such materials includes ethylene copolymers,
such as ethylene-vinyl acetate ("EVA"), ethylene-propylene,
ethylene-ethyl acrylate, and ethylene-acrylic acid; and the
like.
EXAMPLE
[0043] Two polymeric blends were coextruded through multiple
extruders. The two melt streams entered a feed block that split the
outside layer polymer blend into two streams, leaving the
intermediate layer intact. The outer layers thus enclosed or
"sandwiched" the intermediate layer to produce an A-B-A film. 50
wt-% of the film was an immiscible blend of polypropylene and low
density polyethylene ("LDPE") evenly distributed in the two A
layers, and 50 wt-% of the film was an immiscible blend of linear
low density polyethylene ("LLDPE") and ethylene-vinyl acetate
copolymer (8 wt-% vinyl acetate) in the intermediate B layer. The A
layers were formed of 70 wt-% of the polypropylene in the
continuous phase and 30 wt-% of the LDPE in the dispersed phase.
This film was provided as P18-3964 by Clopay Plastic Products
Company, Inc., of Cincinnati, Ohio, USA, and it had an average
basis weight of 20 gsm, a nominal thickness of 8 mils (0.2 mm), and
a titanium dioxide pigment loading of about 6.5 wt-%.
[0044] The A-B-A film was then apertured by applying jets of hot
air and vacuum at about 330 C while being supported by a
cylindrical forming surface substantially as described in James et
al., U.S. Pat. No. 5,916,462, and Zimmerli, U.S. Pat. No.
3,054,148. The differences between the disclosures therein and the
process used herein would not be expected to change the results
described hereinbelow. The resulting apertured film had a repeating
pattern of substantially uniform, round apertures having a diameter
of about 0.62 mm, an open area of about 26%, and an equivalent
hydraulic diameter ("EHD"), as measured by the formula EHD=4*
area/perimeter, of about 26 mils (0.65 mm).
[0045] Open area may be determined by using image analysis to
measure the relative percentages of apertured and unapertured, or
land, areas. Essentially image analysis converts an optical image
from a light microscope into an electronic signal suitable for
processing. An electronic beam scans the image, line-by-line. As
each line is scanned, an output signal changes according to
illumination. White areas produce a relatively high voltage and
black areas a relatively low voltage. An image of the apertured
formed film is produced and, in that image, the holes are white,
while the solid areas of thermoplastic material are at various
levels of gray. The more dense the solid area, the darker the gray
area produced. Each line of the image that is measured is divided
into sampling points or pixels. The following equipment can be used
to carry out the analysis described above: a Quantimet Q520 Image
Analyzer (with v. 5.02B software and Grey Store Option), sold by
LEICA/Cambridge Instruments Ltd., in conjunction with an Olympus
SZH Microscope with a transmitted light base, a plan 1.0.times.
objective, and a 2.50.times. eyepiece. The image can be produced
with a DAGE MTI CCD72 video camera.
[0046] A representative piece of each material to be analyzed is
placed on the microscope stage and sharply imaged on the video
screen at a microscope zoom setting of 10.times.. the open area is
determined from field measurements of representative areas. The
Quantimet program output reports mean value and standard deviation
for each sample.
[0047] EHD was measured according to the procedure disclosed in
Turi et al., U.S. Pat. No. 5,567,376. However, the image was
acquired using a ScanJet 4c scanner from Hewlett-Packard, Palo
Alto, Calif., USA, and analyzed using Image-Pro software from Media
Cybernetics, Silver Springs, Md., USA. These changes do not
significantly alter any results.
[0048] The apertured film was coated with Polysorbate 20 (TWEEN 20,
available from ICI, Atlas Chemical Division, of Wilmington, Del.,
USA, by applying a fine spray of a solution formed of 1 part TWEEN
20 dissolved in 2 parts (v/v) isopropyl alcohol, and it was slit to
a width of about 47 mm. TWEEN 20 was applied to the film substrate
at ambient temperature of about 20 C with a target coating weight
of about 1 wt-%. The coating weight is measured based upon the
TWEEN 20 as the alcohol solvent volatilizes. This is described in
greater detail in commonly assigned, co-pending U.S. application
Ser. No., ______, filed Jun. ______, 1999, entitled "Tampon with
Cover and Nonionic Surfactant" (Attorney Docket PPC-708).
[0049] The slit film was cut to form a cover having a length of
about 125 mm. The cover is applied to an absorbent web comprising
75 wt-% rayon and 25 wt-% cotton having a length of about 235 mm, a
width of about 50 mm and a target weight of about 2.7 g. The cover
was heat sealed to one end of the absorbent web in a manner
generally described in U.S. Ser. No. ______, filed Jun. ______,
1999, entitled "Sealing Roller and Sealing Roller Element,
Particularly for Producing a Tampon for Feminine Hygiene and Method
Therefore" (Attorney Docket, J&J-1819), and copending U.S.
application Ser. No. ______, filed Jun. ______, 1999, entitled
"Continuous Method of Providing Individual Sheets from a Continuous
Web" (Attorney Docket, PPC-668). The covered web was then
compressed in a tampon press, as generally described in Friese et
al., U.S. Ser. No. 07/596,454, filed Oct. 12, 1990, and EP-B-0 422
660. The resulting tampons had a weight of between 2.55 and 3.2 g.
During processing of this film, it was noted that the cover was
heat-sealable without blocking the apertures and without melting
them through, and that the heat-sealable apertured film did not
adhere to the aperturing drum.
[0050] The disclosures of all US patents and patent applications,
as well as any corresponding published foreign patent applications,
mentioned throughout this patent application are hereby
incorporated by reference herein.
[0051] The specification and embodiments above are presented to aid
in the complete and non-limiting understanding of the invention
disclosed herein. Since many variations and embodiments of the
invention can be made without departing from its spirit and scope,
the invention resides in the claims hereinafter appended.
* * * * *