U.S. patent application number 09/746880 was filed with the patent office on 2002-09-12 for absorbent articles with non-aqueous compositions containing anionic polymers.
Invention is credited to Brock, Earl David, Buhrow, Chantel Spring, Cahall, James Louis, Krzysik, Duane Gerard, Lin, Samuel Qcheng, Otts, David Roland, Tyrrell, David John.
Application Number | 20020128615 09/746880 |
Document ID | / |
Family ID | 25002748 |
Filed Date | 2002-09-12 |
United States Patent
Application |
20020128615 |
Kind Code |
A1 |
Tyrrell, David John ; et
al. |
September 12, 2002 |
Absorbent articles with non-aqueous compositions containing anionic
polymers
Abstract
The present invention relates to absorbent articles including
non-aqueous compositions for protecting the barrier function of the
skin. The compositions can be applied to the bodyfacing surfaces of
absorbent articles so that the compositions come into contact with
the skin. The compositions of the invention have improved stability
on the bodyfacing surfaces after processing. The compositions of
the invention provide several benefits including prevention and
alleviation of skin irritations associated with the use of
absorbent articles. The compositions can include emollients,
viscosity enhancers and anionic polymers.
Inventors: |
Tyrrell, David John;
(Appleton, WI) ; Buhrow, Chantel Spring;
(Weyauwega, WI) ; Otts, David Roland; (Appleton,
WI) ; Krzysik, Duane Gerard; (Appleton, WI) ;
Brock, Earl David; (Kimberly, WI) ; Cahall, James
Louis; (Appleton, WI) ; Lin, Samuel Qcheng;
(Paramus, NJ) |
Correspondence
Address: |
KIMBERLY-CLARK WORLDWIDE, INC.
401 NORTH LAKE STREET
NEENAH
WI
54956
|
Family ID: |
25002748 |
Appl. No.: |
09/746880 |
Filed: |
December 22, 2000 |
Current U.S.
Class: |
604/364 ;
424/443; 604/304; 604/360; 604/367; 604/376; 604/378 |
Current CPC
Class: |
A61K 8/25 20130101; A61L
2300/22 20130101; A61K 8/92 20130101; A61L 15/34 20130101; A61K
8/31 20130101; A61L 2300/222 20130101; A61K 8/732 20130101; A61L
2300/30 20130101; A61L 15/44 20130101; A61Q 17/00 20130101; A61K
8/0208 20130101; A61Q 19/00 20130101; A61K 8/731 20130101 |
Class at
Publication: |
604/364 ;
604/304; 604/360; 604/367; 604/378; 604/376; 424/443 |
International
Class: |
A61F 013/15; A61F
013/20 |
Claims
We claim:
1. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 40 to about 95 percent by weight of emollient, from about 0.1
to about 40 percent by weight of viscosity enhancer and from about
0.1 to about 20 percent by weight of decoupling polymer.
2. The absorbent article of claim 1, wherein the composition has a
high shear viscosity less than about 5,000 centipoise at a
temperature greater than about 60.degree. C. and has a low shear
viscosity greater than about 50,000 centipoise at a temperature of
about 55.degree. C.
3. The absorbent article of claim 1, wherein the emollient of the
composition is selected from petrolatum, vegetable based oils,
mineral oils, dimethicone, lanolin, glycerol esters, alkoxylated
carboxylic acids, alkoxylated alcohols, fatty alcohols and mixtures
thereof.
4. The absorbent article of claim 1, wherein the viscosity enhancer
of the composition is selected from polyolefin resins,
lipophilicloil thickeners, ethylene/vinyl acetate copolymers,
organically modified clays, polyethylene, silica, silica silylate,
silica methyl silylate, colloidal silicone dioxide, alkyl hydroxy
ethyl cellulose, microcrystalline wax, shellac wax, hexadecyl
cosanyl hexacosanate, C.sub.20-C.sub.40 alkyl hydroxystearyl
stearate, glycol montanate, ozokerite wax,
polyperfluoromethylisopropylether montan wax and mixtures
thereof.
5. The absorbent article of claim 1, wherein the decoupling polymer
of the composition is selected from homopolymers of acrylic acid,
acrylic acid/maleic acid copolymers, poly(2-hydroxyethylacrylate),
polysaccharides, cellulose ethers, polyglycerols, polyacrylamides,
polyvinyl alcohol/polyvinyl ether copolymers, poly(sodium vinyl
sulfonate), poly(2-sulphato ethyl methacrylate),
poly(acrylamidomethyl propane sulphonate) and mixtures thereof.
6. The absorbent article of claim 1 wherein the composition further
includes from about 5 to about 59 percent by weight of solidifying
agent.
7. The absorbent article of claim 6, wherein the solidifying agent
is selected from beeswax, behenyl behenate, behenyl benzoate,
branched esters, candelilla wax, carnauba wax, synthetic carnauba
wax, PEG-12 carnauba wax, cerasin, microcrystalline wax,
hydrogenated microcrystalline wax, hexadecylcosanyl hexacosanate,
polyperfluoromethylisopropylether montan wax, alkylmethylsiloxanes,
glycol montanate, jojoba wax, lanolin wax, ozokerite, paraffin,
synthetic paraffin, polyethylene, C.sub.20-C.sub.40 alkyl
hydroxystearyl stearate, C.sub.30 alkyl dimethicone, cetyl esters,
zinc stearate, shellac wax, hydrogenated cottonseed oil,
hydrogenated squalene, hydrogenated jojoba oil and mixtures
thereof.
8. The absorbent article of claim 1 wherein the composition further
includes from about 0.1 to about 59 percent by weight of natural
fats or oils.
9. The absorbent article of claim 8, wherein the natural fat or oil
is selected from Avocado Oil, Apricot Oil, Babassu Oil, Borage Oil,
Camellia Oil, Canola Oil, Castor Oil, Coconut Oil, Corn Oil,
Cottonseed Oil, Evening Primrose Oil, Hydrogenated Cottonseed Oil,
Hydrogenated Palm Kernel Oil, Maleated Soybean Oil, Meadowfoam Oil,
Palm Kernel Oil, Peanut Oil, Rapeseed Oil, Safflower Oil,
Sphingolipids, Sweet Almond Oil, Tall Oil, Lauric Acid, Palmitic
Acid, Stearic Acid, Linoleic Acid, Stearyl Alcohol, Lauryl Alcohol,
Myristyl Alcohol, Behenyl Alcohol, Rose Hip Oil, Calendula Oil,
Chamomile Oil, Eucalyptus Oil, Juniper Oil, Sandlewood Oil, Tea
Tree Oil, Sunflower Oil, Soybean Oil and mixtures thereof.
10. The absorbent article of claim 1 wherein the composition
further includes from about 0.1 to about 10 percent by weight of
sterols or sterol derivatives.
11. The absorbent article of claim 10, wherein the sterol or sterol
derivative is selected from cholesterol, sitosterol, stigmasterol,
and ergosterol, as well as, C.sub.10-C.sub.30
cholesterol/lanosterol esters, cholecalciferol, cholesteryl
hydroxystearate, cholesteryl isostearate, cholesteryl stearate,
7-dehydrocholesterol, dihydrocholesterol, dihydrocholesteryl
octyidecanoate, dihydrolanosterol, dihydrolanosteryl
octyldecanoate, ergocalciferol, tall oil sterol, soy sterol
acetate, lanasterol, soy sterol, avocado sterols, sterol esters and
mixtures thereof.
12. The absorbent article of claim 1, wherein the composition
further includes from about 0.5 to about 20 percent by weight of a
rheology modifier.
13. The absorbent article of claim 12, wherein the rheology
modifier is selected from silica, silica silylate, silica methyl
silylate, quaternary starch compounds, quaternary modified clays,
organically modified clays and mixtures thereof.
14. The absorbent article of claim 13, wherein the composition
further comprises from about 1 to about 20 by weight of clay
selected from natural clays and synthetic analogs of natural
clays.
15. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 40 to about 95 percent by weight of emollient, from about 0.1
to about 40 percent by weight of viscosity enhancer and from about
0.1 to about 20 percent by weight of decoupling polymer selected
from homopolymers of acrylic acid, acrylic acid/maleic acid
copolymers, poly(2-hydroxyethylacrylate), polysaccharides,
cellulose ethers, polyglycerols, polyacrylamides, polyvinyl
alcohol/polyvinyl ether copolymers, poly(sodium vinyl sulfonate),
poly(2-sulphato ethyl methacrylate), poly(acrylamidomethyl propane
sulphonate) and mixtures thereof.
16. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 40 to about 95 percent by weight of emollient, from about 0.5
to about 20 percent by weight of rheology modifier and from about 1
to about 20 percent by weight of a clay selected from natural clays
and synthetic analogs of natural clays.
17. The absorbent article of claim 16, wherein the rheology
modifier is selected from silica, organically modified clays,
silica silylate, silica methyl silylate, quaternary modified clays,
quaternary starch compounds and mixtures thereof.
18. The absorbent article of claim 16 wherein the natural clay is
selected from montmorrillonite, bentonite, hectorite, stevensite,
beidellite, saponite, magnesium aluminum silicate and mixtures
thereof.
19. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 20 to about 95 percent by weight of emollient, from about 1
to about 40 percent by weight of viscosity enhancer, from about 0.5
to about 20 percent by weight of rheology modifier and from about 1
to about 20 percent by weight of zinc oxide.
20. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 0.1 to about 95 percent by weight of natural fats or oils,
from about 0.1 to about 10 percent by weight of sterols or sterol
derivatives, from about 1 to about 95 percent by weight of
emollient, from about 0.1 to about 40 percent by weight of
viscosity enhancer and from about 0.1 to about 20 percent by weight
of decoupling polymer.
21. The absorbent article of claim 20, wherein the composition has
a melting point from about 32.degree. C. to about 100.degree.
C.
22. The absorbent article of claim 20, wherein the composition has
a high shear viscosity less than about 5,000 centipoise at a
temperature greater than about 60.degree. C. and has a low shear
viscosity greater than about 50,000 centipoise at a temperature of
about 55.degree. C.
23. The absorbent article of claim 20, wherein the composition has
a penetration hardness of from about 5 millimeters to about 365
millimeters at 25.degree. C.
24. The absorbent article of claim 20, wherein the composition is
on the bodyfacing surface in an amount of from about 0.1 grams per
meter squared (g/m2) to about 30 g/m2.
25. The absorbent article of claim 20, wherein the natural fat or
oil of the composition is selected from Avocado Oil, Apricot Oil,
Babassu Oil, Borage Oil, Camellia Oil, Canola Oil, Castor Oil,
Coconut Oil, Corn Oil, Cottonseed Oil, Evening Primrose Oil,
Hydrogenated Cottonseed Oil, Hydrogenated Palm Kernel Oil, Maleated
Soybean Oil, Meadowfoam Oil, Palm Kernel Oil, Peanut Oil, Rapeseed
Oil, Safflower Oil, Sphingolipids, Sweet Almond Oil, Tall Oil,
Lauric Acid, Palmitic Acid, Stearic Acid, Linoleic Acid, Stearyl
Alcohol, Lauryl Alcohol, Myristyl Alcohol, Behenyl Alcohol, Rose
Hip Oil, Calendula Oil, Chamomile Oil, Eucalyptus Oil, Juniper Oil,
Sandlewood Oil, Tea Tree Oil, Sunflower Oil, Soybean Oil and
mixtures thereof.
26. The absorbent article of claim 20, wherein the sterol or sterol
derivative of the composition is selected from cholesterol,
sitosterol, stigmasterol, and ergosterol, as well as,
C.sub.10-C.sub.30 cholesterol/lanosterol esters, cholecalciferol,
cholesteryl hydroxystearate, cholesteryl isostearate, cholesteryl
stearate, 7-dehydrocholesterol, dihydrocholesterol,
dihydrocholesteryl octyldecanoate, dihydrolanosterol,
dihydrolanosteryl octyldecanoate, ergocalciferol, tall oil sterol,
soy sterol acetate, lanasterol, soy sterol, avocado sterols, sterol
esters and mixtures thereof.
27. The absorbent article of claim 20, wherein the emollient of the
composition is selected from petrolatum, vegetable based oils,
mineral oils, dimethicone, lanolin, glycerol esters, alkoxylated
carboxylic acids, alkoxylated alcohols, fatty alcohols and mixtures
thereof.
28. The absorbent article of claim 20, wherein the viscosity
enhancer of the composition is selected from polyolefin resins,
lipophilic/oil thickeners, ethylene/vinyl acetate copolymers,
organically modified clays, polyethylene, silica, silica silylate,
silica methyl silylate, colloidal silicone dioxide, alkyl hydroxy
ethyl cellulose, microcrystalline wax, shellac wax, hexadecyl
cosanyl hexacosanate, C.sub.20-C.sub.40 alkyl hydroxystearyl
stearate, glycol montanate, ozokerite wax,
polyperfluoromethylisopropylether montan wax and mixtures
thereof.
29. The absorbent article of claim 20, wherein the decoupling
polymer of the composition is selected from homopolymers of acrylic
acid, acrylic acid/maleic acid copolymers,
poly(2-hydroxyethylacrylate), polysaccharides, cellulose ethers,
polyglycerols, polyacrylamides, polyvinyl alcohol/polyvinyl ether
copolymers, poly(sodium vinyl sulfonate), poly(2-sulphato ethyl
methacrylate), poly(acrylamidomethyl propane sulphonate) and
mixtures thereof.
30. The absorbent article of claim 20, wherein the composition
further includes from about 5 to about 58 percent by weight of
solidifying agent.
31. The absorbent article of claim 30, wherein the solidifying
agent of the composition is selected from beeswax, behenyl
behenate, behenyl benzoate, branched esters, candelilla wax,
carnauba wax, synthetic carnauba wax, PEG-12 carnauba wax, cerasin,
microcrystalline wax, hydrogenated microcrystalline wax,
hexadecylcosanyl hexacosanate, polyperfluoromethylisopropylether
montan wax, alkylmethylsiloxanes, glycol montanate, jojoba wax,
lanolin wax, ozokerite, paraffin, synthetic paraffin, polyethylene,
C.sub.20-C.sub.40 alkyl hydroxystearyl stearate, C.sub.30 alkyl
dimethicone, cetyl esters, zinc stearate, shellac wax, hydrogenated
cottonseed oil, hydrogenated squalene, hydrogenated jojoba oil and
mixtures thereof.
32. The absorbent article of claim 20, wherein the composition
further includes from about 0.5 to about 20 percent by weight of a
rheology modifier.
33. The absorbent article of claim 32, wherein the rheology
modifier is selected from silica, silica silylate, silica methyl
silylate, quaternary starch compounds, quaternary modified clays,
organically modified clays and mixtures thereof.
34. The absorbent article of claim 32 wherein the composition
further comprises from about 1 to about 20 percent by weight of a
clay selected from natural clays and synthetic analogs of natural
clays.
35. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 0.1 to about 95 percent by weight of natural fats or oils,
from about 0.1 to about 10 percent by weight of sterols or sterol
derivatives, from about 1 to about 95 percent by weight of
emollient, from about 0.1 to about 40 percent by weight of
viscosity enhancer and from about 0.1 to about 20 percent by weight
of decoupling polymer selected from homopolymers of acrylic acid,
acrylic acid/maleic acid copolymers, poly(2-hydroxyethylacrylate),
polysaccharides, cellulose ethers, polyglycerols, polyacrylamides,
polyvinyl alcohol/polyvinyl ether copolymers, poly(sodium vinyl
sulfonate), poly(2-sulphato ethyl methacrylate),
poly(acrylamidomethyl propane sulphonate) and mixtures thereof.
36. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 0.1 to about 95 percent by weight of natural fats or oils,
from about 0.1 to about 10 percent by weight of sterols or sterol
derivatives, from about 1 to about 95 percent by weight of
emollient, from about 0.1 to about 40 percent by weight of
viscosity enhancer, from about 0.5 to about 20 percent by weight of
rheology modifier and from about 1 to about 20 percent by weight of
clay selected from natural clays and synthetic analogs of natural
clays.
37. The absorbent article of claim 36, wherein the rheology
modifier is selected from silica, organically modified clays,
silica silylate, silica methyl silylate, quaternary starch
compounds, quaternary modified clays and mixtures thereof.
38. The absorbent article of claim 36 wherein the natural clay is
selected from montmorrillonite, bentonite, hectorite, stevensite,
beidellite, saponite, magnesium aluminum silicate and mixtures
thereof.
39. An absorbent article comprising: (a) an outer cover; (b) a
liquid permeable bodyside liner that defines a bodyfacing surface
and that is connected in superposed relation to the outer cover;
(c) an absorbent body that is located between the bodyside liner
and the outer cover; and (d) a composition on at least a portion of
the bodyfacing surface of the bodyside liner that includes from
about 0.1 to about 95 percent by weight of natural fats or oils,
from about 0.1 to about 10 percent by weight of sterols or sterol
derivatives, from about 1 to about 95 percent by weight of
emollient, from about 1 to about 40 percent by weight of viscosity
enhancer, from about 0.5 to about 20 percent by weight of rheology
modifier and from about 1 to about 20 percent by weight of zinc
oxide.
40. A method of applying a composition to a bodyfacing surface of a
bodyside liner of an absorbent article comprising the steps of: (a)
heating a composition comprising an emollient, a viscosity enhancer
and a decoupling polymer, to a temperature above the melting point
of the composition, the composition having a melting point of from
about 32.degree. C. to about 100.degree. C.; (b) applying the
composition to the bodyfacing surface of a bodyside liner of an
absorbent article; and (c) resolidifying the composition.
41. The method of claim 40, wherein after the step of
resolidification, the composition has a viscosity of greater than
about 50,000 centipoise.
42. The method of claim 40, wherein after the step of heating, the
composition is applied by spraying.
43. The method of claim 40, wherein after the step of heating, the
composition is applied by slot coating.
44. The method of claim 40, wherein after the step of heating, the
composition is applied by printing.
45. The method of claim 40, wherein the emollient of the
composition is from about 5 to about 95 percent by weight of the
composition and is selected from petrolatum, vegetable based oils,
mineral oils, dimethicone, lanolin, glycerol esters, alkoxylated
carboxylic acids, alkoxylated alcohols, fatty alcohols and mixtures
thereof.
46. The method of claim 40, wherein the viscosity enhancer of the
composition is from about 0.1 to about 40 percent by weight of the
composition and is selected from polyolefin resins, lipophilic/oil
thickeners, ethylene/vinyl acetate copolymers, organically modified
clays, polyethylene, silica, silica silylate, silica methyl
silylate, colloidal silicone dioxide, alkyl hydroxy ethyl
cellulose, microcrystalline wax, shellac wax, hexadecyl cosanyl
hexacosanate, C20-C40 alkyl hydroxystearyl stearate, glycol
montanate, ozokerite wax, polyperfluoromethylisopropylether montan
wax and mixtures thereof.
47. The method of claim 40, wherein the decoupling polymer of the
composition is from about 1 to about 20 percent by weight of the
composition and is selected from homopolymers of acrylic acid,
acrylic acid/maleic acid copolymers, poly(2-hydroxyethylacrylate,
polysaccharides, cellulose ethers, polyglycerols, polyacrylamides,
polyvinyl alcohol/polyvinyl ether copolymers, poly(sodium vinyl
sulfonate), poly(2-sulphato ethyl methacrylate),
poly(acrylamidomethyl propane sulphonate) and mixtures thereof.
48. The method of claim 40, wherein the composition further
includes from about 5 to about 95 percent by weight of solidifying
agent selected from beeswax, behenyl behenate, behenyl benzoate,
branched esters, candelilla wax, carnauba wax, synthetic carnauba
wax, PEG-12 carnauba wax, cerasin, microcrystalline wax,
hydrogenated microcrystalline wax, hexadecylcosanyl hexacosanate,
polyperfluoromethylisopropylether montan wax, alkylmethylsiloxanes,
glycol montanate, jojoba wax, lanolin wax, ozokerite, paraffin,
synthetic paraffin, polyethylene, C.sub.20-C.sub.40 alkyl
hydroxystearyl stearate, C.sub.30 alkyl dimethicone, cetyl esters,
zinc stearate, shellac wax, hydrogenated cottonseed oil,
hydrogenated squalene, hydrogenated jojoba oil and mixtures
thereof.
49. The method of claim 40 wherein the composition further includes
from about 0.1 to about 95 percent by weight of natural fats or
oils selected from Avocado Oil, Apricot Oil, Babassu Oil, Borage
Oil, Camellia Oil, Canola Oil, Castor Oil, Coconut Oil, Corn Oil,
Cottonseed Oil, Evening Primrose Oil, Hydrogenated Cottonseed Oil,
Hydrogenated Palm Kernel Oil, Maleated Soybean Oil, Meadowfoam Oil,
Palm Kernel Oil, Peanut Oil, Rapeseed Oil, Safflower Oil,
Sphingolipids, Sweet Almond Oil, Tall Oil, Lauric Acid, Palmitic
Acid, Stearic Acid, Linoleic Acid, Stearyl Alcohol, Lauryl Alcohol,
Myristyl Alcohol, Behenyl Alcohol, Rose Hip Oil, Calendula Oil,
Chamomile Oil, Eucalyptus Oil, Juniper Oil, Sandlewood Oil, Tea
Tree Oil, Sunflower Oil, Soybean Oil and mixtures thereof.
50. The method of claim 40 wherein the composition further includes
from about 0.1 to about 10 percent by weight of sterols or sterol
derivatives selected from cholesterol, sitosterol, stigmasterol,
and ergosterol, as well as, C.sub.10-C.sub.30
cholesterol/lanosterol esters, cholecalciferol, cholesteryl
hydroxystearate, cholesteryl isostearate, cholesteryl stearate,
7-dehydrocholesterol, dihydrocholesterol, dihydrocholesteryl
octyldecanoate, dihydrolanosterol, dihydrolanosteryl
octyldecanoate, ergocalciferol, tall oil sterol, soy sterol
acetate, lanasterol, soy sterol, avocado sterols, sterol esters and
mixtures thereof.
51. The method of claim 40, wherein the composition further
includes from about 0.5 to about 20 percent by weight of a rheology
modifier selected from silica, silica silylate, silica methyl
silylate, quaternary starch compounds, quaternary modified clays,
organically modified clays and mixtures thereof.
52. The method of claim 51, wherein the composition further
includes from about 1 to about 20 percent by weight of clay
selected from natural clays and synthetic analogs of natural
clays.
53. A method for protecting the skin barrier on a skin surface of a
user, comprising the steps of: a) contacting the skin surface of
the user with a bodyfacing surface of a liner material, the
bodyfacing surface having a composition comprising an emollient, a
viscosity enhancer and a decoupling polymer; b) maintaining the
bodyfacing surface in contact with the skin surface for a
sufficient amount of time to transfer the composition to the skin
surface; and c) repeating the contact of the skin surface with the
bodyfacing surface of the liner material for a sufficient period of
time to enhance skin barrier function, wherein the composition
comprises from about 1 to about 95 percent by weight of an
emollient, from about 1 to about 40 percent by weight of a
viscosity enhancer and from about 0.1 to about 20 percent by weight
of a decoupling polymer selected from homopolymers of acrylic acid,
acrylic acid/maleic acid copolymers, poly(2-hydroxyethylacrylate),
polysaccharides, cellulose ethers, polyglycerols, polyacrylamides,
polyvinyl alcohol/polyvinyl ether copolymers, poly(sodium vinyl
sulfonate), poly(2-sulphato ethyl methacrylate),
poly(acrylamidomethyl propane sulphonate) and mixtures thereof.
54. The method of claim 53, wherein the composition has a melting
point from about 32.degree. C. to about 100.degree. C.
55. The method of claim 53, wherein the composition has a viscosity
greater than about 50,000 centipoise at a temperature of about
55.degree. C.
56. The method of claim 53, wherein the composition has a
penetration hardness of from about 5 to about 365 millimeters at
25.degree. C.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the inclusion of
non-aqueous compositions that contain anionic polymers on the
bodyfacing materials of disposable absorbent articles, such as
diapers, training pants, adult incontinence products, underpants,
feminine care products, nursing pads, wound dressings and similar
articles having absorbent capacity. The present invention also
relates to improving skin health through delivery of non-aqueous
compositions containing anionic polymers from the bodyfacing
materials of disposable absorbent articles to the skin. Prior to
delivery to the skin, the compositions are stable on the bodyfacing
materials. The compositions of the invention can also improve skin
health when they are incorporated into other skin-contacting
materials such as tissues, wet wipes and cosmetic cleansing or
buffing pads.
BACKGROUND OF THE INVENTION
[0002] The stratum corneum is the outer-most layer of the skin and
is responsible for regulating skin water levels and functioning as
a barrier against chemicals and other stress agents found in the
environment. The complex arrangement of lipids in the intercellular
space of the stratum corneum is responsible for the establishment
of normal barrier function. Multi-layered structures of
cholesterol, ceramides and fatty acids, as well as some other minor
lipids, provide the major barrier to the transport of substances
into or through the skin. The overall structure of the stratum
corneum acts as the frontline barrier to the skin. The link between
skin barrier function and skin health is apparent from the skin
inflammation caused by lipid extraction from the skin. That is,
when skin barrier function is impaired, the other layers of the
skin can be injured and have a response to that injury in the form
of inflammation.
[0003] In the area of skin health, it is known to apply
lipid-containing compositions to the skin in order to enhance the
barrier function of the stratum corneum. This approach is disclosed
in U.S. Pat. No. 5,643,899 issued to Elias et al. on Jul. 1, 1997.
For some time, those of skill in the art have believed that it is
necessary to apply all three of the lipid components of the stratum
corneum (cholesterol, ceramides and fatty acids) to the skin in
order to replenish and repair the skin and in order to not affect
the normal repair processes of the skin. In particular, ceramides
are believed to be very important. In fact, the art teaches that if
fewer than all three of the components are used in a skin
composition, the composition could actually compromise or delay
repair of the barrier.
[0004] In U.S. patent application Ser. No. 09/379,928 filed Aug.
24, 1999, various compositions for improving skin health are
described, including compositions suitable for use in conjunction
with absorbent articles. The compositions in patent application
Ser. No. 09/379,928 were found to provide benefits for skin health.
The compositions were described as containing a variety of
potential components and, in some forms, the compositions included
natural fats and oils, sterols and sterol derivatives, humectants
and surfactants. These compositions have been found to improve skin
health even though they do not necessarily include any ceramides.
Efficacy without ceramides was unexpected. Though the exact
mechanism of functionality was not known, one hypothesis was that
an emulsion of the lipid components (natural fats/oils and
sterols/sterol derivatives) was formed in the humectant component
(through the use of a surfactant). In some of the aspects that were
described, the humectant was glycerin. Incorporation of such an
emulsion into an ointment formulation was predicted to be more
easily absorbed or taken up by the skin. The ointment formulation,
which could include petrolatum, would form an occlusive film on the
skin, thereby trapping water between the skin and the occlusive
film. The trapped water was predicted to facilitate uptake of the
emulsion and, therefore, the natural fats/oils and sterols, by the
skin. Therefore, the humectant and surfactant components of the
compositions were perceived to be facilitating the transfer of the
lipid components to the skin.
[0005] Therefore, benefits and improvements to skin health have
been observed when compositions containing the lipids naturally
present in the stratum corneum are applied to the skin. Though the
exact mechanisms are not known, one hypothesis is that the lipids
being applied with the compositions are replenishing lipids that
have been lost from the stratum corneum as a result of physical or
biological insults. Another hypothesis is that the lipids being
applied with the compositions are providing additional lipids to
the stratum corneum resulting in better protection against insults.
The stratum corneum of the skin is constantly exposed to physical
and biological insults that could have a negative effect on barrier
function.
[0006] Absorbent articles such as diapers, training pants,
incontinence products and feminine care products are worn such that
they are in direct contact with the skin of the wearer. An
unavoidable consequence of the use of absorbent articles is that
the skin is exposed more directly to various physical and
biological insults. Consequently, the barrier function of the skin
covered by the absorbent article is put at risk. In order to
provide disposability, absorbent articles are primarily constructed
of nonwoven materials. Even though nonwoven materials are
engineered to have soft hand and drape, they rub against the skin
and there is friction. Such friction constitutes one form of
physical insult to the skin barrier. Friction against the skin
barrier also occurs with the use of absorbent tissues and wipes.
Absorbent tissue and wipe products are frequently used for
cleansing the skin areas covered by absorbent articles. Absorbent
tissue and wipe products are necessary for removing biological
waste materials from the skin.
[0007] In addition to these physical insults, skin covered by
absorbent articles is also frequently exposed to biological
insults. Biological fluids, such as urine, feces, vaginal
secretions and nasal secretions, may contain a variety of
components that can damage the skin barrier. Examples of these
components include proteases, lipases and bile acids. Once the skin
barrier is compromised, these components, in addition to other
constituents of biological fluids, can initiate or exacerbate
inflammation of the skin.
[0008] Diaper dermatitis is a genre of skin conditions that, in
large part, originate from impaired skin barrier function.
Impairment of the skin barrier can result from a variety of
factors, including: increased skin hydration due to the occlusion
of the skin caused by diapers, enzymatic skin damage due to fecal
and urinary enzymes, and physical damage caused by friction against
the diaper surface and repeated cleaning of the skin with absorbent
tissues or wet wipes.
[0009] Excessive hydration of the skin also has a negative effect
on the skin barrier. The hydration level of diapered skin, for
example, may reach between five to ten times that of undiapered
skin. Frequent contact of diapered skin with urine may also
contribute to increased skin hydration. Increased skin hydration
disrupts skin lipid organization in the stratum corneum. This
disruption may increase the permeability of the skin to irritants
from feces and urine, thus increasing the risk of skin
inflammation.
[0010] Disposable absorbent articles such as diapers, training
pants, adult incontinence products, absorbent under pants, feminine
care products and nursing pads have been used to absorb body fluids
and leave the skin dry. Disposable absorbent articles of this type
generally include a liquid impermeable backsheet member, an
absorbent core or assembly, and a liquid permeable body facing or
liner material. The body facing or liner material comes into
contact with the wearer's skin. While the body facing material is
made of a soft, compliant material, the material rubs against the
skin during use and may not leave the skin completely dry and free
of the bodily fluids, such as solid or semi-solid waste, the
absorbent article is trying to absorb. During frequent insults of
bodily fluids and frequent use of disposable absorbent articles,
the skin can become irritated and appear red and be sore to the
touch.
[0011] Creams, lotions or ointments can be used to provide an
artificial hydrophobic barrier on the skin and to treat skin
conditions such as diaper rash. Application of these types of
products to the skin is often messy and inconvenient. Often, these
products are not used prophylactically and are only used when signs
of diaper rash are visible.
[0012] Diaper liners and other bodyfacing materials may be treated
with emollients, such as petrolatum, that can be transferred to the
skin through normal diapering practices. Once transferred to the
skin, diaper liner formulations may provide an artificial barrier
against feces and urine. These formulations may require high
concentrations of petrolatum to ensure sufficient transfer to the
skin to provide a benefit. High concentrations of petrolatum can be
messy, greasy to the touch, and may impair the fluid handling
properties of an absorbent article, such as a diaper. The slow
penetration of petrolatum into the skin can lead to smearing of the
agent over the skin and onto clothes and other materials.
[0013] Formulations, such as those containing petrolatum, are
applied to the bodyfacing materials of absorbent articles during
manufacture. In order to process and apply the formulations to the
bodyfacing materials, the formulations need to be in a semi-solid
or fluid state. However, in order to have stability on the
bodyfacing material after manufacture, the formulations need to be
semi-solid or solid across a wide range of shipping and storage
temperatures. Not all of the presently known formulations are
sufficiently stable on the bodyfacing materials. Consequently, such
formulations may transfer off of the bodyfacing material
prematurely or the formulations may migrate away from the
skin-facing surfaces of the materials.
[0014] Other compositions are known for treating skin irritations,
such as diaper rash. For example, U.S. Pat. No. 5,869,033 issued to
Schulz on Feb. 9, 1999 describes organophilic clays as being
effective for inactivating irritating fecal proteolytic enzymes.
The Schulz patent describes organophilic clays as clays that have
been treated with long-chain organic amphiphilic compounds such as
long-chain quaternary amines so as to result in the exchange of
alkali metal ions by cationic organic molecules to render the clay
organophilic. Therefore, the clays described as being capable of
adsorbing and inactivating fecal enzymes in the Schulz patent are
modified clays. The Schulz patent describes hydrophilic clays such
as montmorillonite, bentonite, beidellite, hectorite, saponite and
stevensite as suitable thickeners for vehicles that include the
organophilic clays. The Schulz patent does not, however, recognize
any anti-irritation benefit of hydrophilic clays. Though
hydrophobic vehicles are described as being suitable vehicles for
the organophilic clays, the Schulz patent discourages the use of
vehicle compounds having relatively long hydrocarbon chains (C-8
and longer) because of their interaction with the organophilic
clays that causes the organophilic clays to have diminished
adsorptive capability for fecal enzymes.
[0015] In U.S. patent application Ser. No. 09/475,535 filed Dec.
30, 1999, compositions for use in conjunction with absorbent
articles are taught. The compositions include unmodified clays for
the purpose of sequestering skin irritants such as fecal enzymes.
The U.S. application Ser. No. 09/475,535 recognizes an efficacy for
unmodified clays that was not disclosed or suggested by the Schulz
patent. Further, the U.S. application Ser. No. 09/475,535 teaches
unmodified clays as having sequestering activity in compositions
containing long hydrocarbon chains of C-8 or longer.
[0016] Thus, what is needed is a topically effective composition
delivered from a bodyside or bodyfacing material of an absorbent
article that protects, maintains, recovers or otherwise benefits
skin barrier function against physical damage and irritants in
biological fluids. It would also be desirable to provide a topical
composition delivered from a bodyside material of an absorbent
article that absorbs into the skin, is non-greasy and cosmetically
acceptable to the consumer. Additionally, it would be desirable to
provide a topical composition having improved stability on the
bodyside material of an absorbent article. Further, it would be
desirable to provide a topical composition delivered from a
bodyside material of an absorbent article that does not impair the
waste containment functions of the absorbent article.
SUMMARY OF THE INVENTION
[0017] In response to the difficulties and problems discussed
above, compositions and the use of those compositions on absorbent
articles for protecting the skin barrier and subduing the
inflammatory response of the skin have been discovered. The
compositions of the invention provide several benefits associated
with barrier function including protecting the skin barrier and
subduing the inflammatory response of the skin barrier. While the
compositions of the inventions can have a variety of applications,
the compositions are particularly beneficial when used in
conjunction with absorbent articles such as diapers, incontinence
garments, feminine care products, training pants, diaper pants,
nursing pads and wound dressings. Additionally, the compositions of
the invention could also provide benefits when used in conjunction
with tissue, pre-moistened wipe products and cosmetic cleansing and
buffing pads. A further benefit of the compositions of the
invention is that the compositions show improved stability during
processing and application to an article. An additional benefit of
the compositions of the invention is that the compositions show
improved transfer to the skin. The purposes and advantages of the
present invention will be set forth in and apparent from the
description that follows, as well as will be learned by practice of
the invention. Additional advantages of the invention will be
realized and attained by the compositions and articles particularly
pointed out in the written description and claims hereof, as well
as from the appended drawings.
[0018] In one aspect, the present invention relates to an absorbent
article that includes an outer cover, a bodyside liner, an
absorbent body and a composition. The bodyside liner is typically
liquid permeable and defines a bodyfacing surface. The bodyside
liner is connected in a generally superposed relation to the outer
cover. The absorbent body is located between the bodyside liner and
the outer cover. The composition is on a portion or the entire
bodyfacing surface of the bodyside liner. The composition can be
generally solid, semi-solid or liquid. The composition may be in a
variety of forms, including, but not limited to, emulsions,
lotions, creams, ointments, salves, suspensions, gels and the like.
The composition can be applied to the bodyside liner using a
variety of techniques including foam application, spraying, slot
coating and printing. The present invention also encompasses
technology that would permit integration of the composition
directly with fibers or other materials used to form the bodyside
liner. The compositions can be applied to the bodyfacing surface in
amounts of from about 0.1 grams per meter squared (g/m.sup.2) to
about 30 g/m.sup.2. The compositions of the invention could also be
applied to or be present on other skin contacting surfaces of
absorbent articles such as the waist and leg elastics and the
containment flaps.
[0019] The compositions of the invention can include from about 5
to about 95 percent by weight of one or more emollients. More
specifically, the compositions include from about 20 to about 75
percent by weight of emollient(s). Emollients are skin conditioning
ingredients that help to soften, smooth, plasticize, lubricate,
moisturize, improve the appearance of, improve the feel of and
protect the skin. Even more specifically, the compositions include
from about 40 to about 60 percent by weight of emollient(s).
Suitable emollients include petroleum based oils, petrolatum,
vegetable oils, hydrogenated vegetable oils, animal oils,
hydrogenated animal oils, mineral oils, alkyl dimethicones, alkyl
methicones, alkyldimethicone copolyols, phenyl silicones, alkyl
trimethylsilanes, dimethicone, lanolin and its derivatives, esters,
branched esters, glycerol esters and their derivatives, propylene
glycol esters and their derivatives, alkoxylated carboxylic acids,
alkoxylated alcohols, fatty alcohols, triglycerides, alkyl
hydroxystearates and mixtures of such compounds.
[0020] The compositions of the invention also include from about 5
to about 95 percent by weight of one or more solidifying agents.
More specifically, the compositions include from about 25 to about
75 percent by weight of solidifying agents. Even more specifically,
the compositions include from about 40 to about 60 percent by
weight of solidifying agents. A solidifying agent is a material
capable of solidifying the composition so that the composition is
solid at room temperature and has a penetration hardness of at
least 5 mm. More specifically, the solidifying agent includes one
or more materials that are capable of solidifying the natural
fats/oils and emollient combination so as to have a penetration
hardness of 5 to about 365 mm at 25.degree. C. Further, the
solidifying agent solidifies the emollient (or the
fat/oil/emollient combination when fats and oils are used in the
composition) so that it has a melting point between 32.degree. C.
and 100.degree. C. One or more solidifying agents can be selected
from alkyl siloxanes (with a melting point greater than 35.degree.
C.), polymers, waxes (animal, vegetable or mineral), hydrogenated
vegetable/animal oils having a melting point of 35.degree. C. or
greater, fatty acid esters having a melting point of 35.degree. C.
or greater, alkyl hydroxystearates (>C.sub.16), branched esters,
alkoxylated alcohols, and alkoxylated carboxylic acid.
[0021] Examples of suitable solidifying agents include, but are not
limited to, the following compounds: alkyl silicones, alkyl
trimethylsilanes, beeswax, behenyl behenate, behenyl benzoate,
C.sub.24-C.sub.28 alkyl dimethicone, C.sub.30 alkyl dimethicone,
cetyl methicone, stearyl methicone, cetyl dimethicone, stearyl
dimethicone, cerotyl dimethicone, candelilla wax, carnauba,
synthetic carnauba, PEG-12 carnauba, cerasin, hydrogenated
microcrystalline wax, jojoba wax, microcrystalline wax, lanolin
wax, ozokerite, paraffin, synthetic paraffin, cetyl esters, behenyl
behenate, C.sub.20-C.sub.40 alkyl behenate, C.sub.12-C.sub.15
lactate, cetyl palmitate, stearyl palmitate, isosteryl behenate,
lauryl behenate, stearyl benzoate, behenyl isostearate, cetyl
myristate, cetyl octanoate, cetyl oleate, cetyl ricinoleate, cetyl
stearate, decyl oleate, di-C.sub.12-C.sub.15 alkyl fumerate,
dibehenyl fumerate, myristyl lactate, myristyl lignocerate,
myristyl myristate, myristyl stearate, lauryl stearate,
octyidodecyl stearate, octyldodecyl stearoyl stearate, oleyl
arachidate, oleyl stearate, tridecyl behenate, tridecyl stearate,
tridecyl stearoyl stearate, pentaerythrityl tetrabehenate,
pentaerythritylhydrogenated rosinate, pentaerythrityl distearate,
pentaerythrityl tetraabeite, pentaerythrityl tetracocoate,
pentaerythrityl tetraperlargonate, pentaerythrityl tetrastearate,
ethylene vinyl acetate, polyethylene, hydrogenated cottonseed oil,
hydrogenated vegetable oil, hydrogenated squalene, hydrogenated
coconut oil, hydrogenated jojoba oil, hydrogenated palm oil,
hydrogenated palm kernel oil, hydrogenated olive oil, polyamides,
metal stearates and other metal soaps, C.sub.30-C.sub.60 fatty
alcohols, C.sub.20+fatty amides, polypropylene, polystyrene,
polybutane, polybutylene terephthalate, polydipentane,
polypropylene, zinc stearate, dodecyl laurate, stearyl palmitate,
octadecyl hexadecanoate, octadecyl palmitate, stearyl behenate,
docosyl octanoate, tetradecyl-octadecanyl behenate,
hexadecyl-cosanyl hexacosanate, shellac wax, glycol montanate,
fluoranated waxes, C.sub.20-C.sub.40 alkyl hydroxystearyl stearate
and mixtures of such compounds.
[0022] In addition to the components already described, the
compositions of the invention may further include from about 0.1 to
about 40 percent by weight of one or more compounds acting as
viscosity enhancers that increase the meltpoint viscosity of the
emollients of the composition. More specifically, the compositions
include from about 5 to about 20 percent by weight of one or more
viscosity enhancers. Even more specifically, the compositions
include from about 10 to about 15 percent by weight of viscosity
enhancer(s). The viscosity enhancer increases the meltpoint
viscosity of the compositions to have a high viscosity under low
shear and at the "hot box car" stability temperature of
approximately 54.5.degree. C. Having high viscosity (>50,000
centipoise) at elevated temperatures prevents the compositions from
migrating into or away from the materials to which they are
applied. However, the viscosity enhancer component also provides a
low viscosity (<5,000 centipoise) for the compositions under
high shear and at processing temperatures. The viscosity enhancers
of the invention are capable of providing a desirable viscosity,
depending on shear and temperature conditions, for compositions
having a range of melting points. While it is desirable for
compositions of the invention to have increased viscosity under
"hot box car" stability conditions, the increased viscosity can be
maintained, in part, through the use of one or more viscosity
enhancers up to the melting point of the particular composition.
Typically, process temperatures are approximately 5.degree. C.
above the melting point of the composition. Examples of suitable
viscosity enhancers include polyolefin resins, lipophilic/oil
thickeners, ethylene/vinyl acetate copolymers, organically modified
clays, polyethylene, silica, silica silylate, silica methyl
silylate, colloidal silicone dioxide, alkyl hydroxy ethyl
cellulose, other organically modified celluloses, PVP/decane
copolymer, PVMIMA decadiene crosspolymer, PVP/eicosene copolymer,
PVP/hexadecane copolymer, microcrystalline wax,
hexadecyl-cosanyl-hexacosanate, shellac wax, glycol montanate,
PEG-12 carnauba, synthetic paraffin, ozokerite, C.sub.20-C.sub.40
alkyl hydroxystearyl stearate, polyperfluoromethylisopropylether
montan wax and mixtures of these compounds. Many of the solidifying
agents, also described herein, have been found to provide the same
benefits to the compositions of the invention as the viscosity
enhancers.
[0023] The compositions of the invention can also include from
about 0.1 to about 20 percent by weight of one or more anionic
polymers, such as anionic decoupling polymers. More specifically,
the compositions can include from about 0.5 to about 20 percent by
weight of one or more decoupling polymers. Even more specifically,
the compositions include from about 1 to about 7 percent by weight
of decoupling polymers. The decoupling polymers, in combination
with the other components of the composition, provide several
benefits to the skin, particularly skin that is frequently covered
by an absorbent article and that is exposed to biological
insults.
[0024] As a class, anionic polymers can contribute to providing the
skin health benefits of the compositions of the invention. Anionic
polymers are polymers that carry negative charges at their
functional groups which may include carboxylates, sulphonates and
other such functional groups. The number of negative charges
carried by an anionic polymer depends on the number of functional
groups that the polymer has. Generally speaking, the anionic
polymers that contribute to improving skin health in the
compositions of the invention are water-soluble polymers. However,
the compositions of the invention are not limited to including
water-soluble polymers. The anionic polymers may also have
hydrophobic groups, such as lauryl and stearyl groups. These
anionic polymers become hydrophobically modified polymers. Because
such polymers have both hydrophilic and hydrophobic groups in the
same molecule, the polymers behave like surfactants. These
"surfactant-like" polymers are surface active and like to situate
themselves at the interface between hydrophilic and hydrophobic
components. Sometimes, these "surfactant-like" polymers are also
referred to as "polysoaps".
[0025] Examples of decoupling polymers that have been found to
provide skin health benefits in the compositions of the invention
include those polymers having a hydrophilic backbone. The
hydrophilic backbone of the decoupling polymers can be composed of
one or two monomer types or can be composed of three or more
different monomer types. The decoupling polymers of the invention
can include one or more polymers having a hydrophilic backbone of
homopolymers of acrylic acid, acrylic acid/maleic acid copolymers,
poly(2-hydroxyethyl acrylate), polysaccharides, cellulose ethers,
polyglycerols, polyacrylamides, polyvinylalcohol/polyvi- nylether
copolymers, poly(sodium vinyl sulphonate), poly(2-sulphato ethyl
methacrylate), poly(acrylamidomethylpropane sulphonate) and
mixtures of such polymers.
[0026] While the decoupling polymers of the invention may have a
hydrophilic backbone, it is desirable for the decoupling polymers
to have one or more hydrophobic side chains. The hydrophobic side
chains can be part of a monomer unit that is incorporated into the
decoupling polymer by copolymerization with the hydrophilic
backbone. While a variety of hydrophobic side chains can be
copolymerized into the decoupling polymers, the hydrophobic side
chains can include those side chains that, when isolated from their
linkage, are relatively water insoluble. For example, the
hydrophobic side chains and monomers can have solubilities of less
than 1 g/l, less than 0.5 g/l or less than 0.1 g/l in water at
ambient temperature and at a pH of about 3 to about 12.5.
[0027] The hydrophobic side chains can include siloxanes and
saturated and unsaturated alkyl chains. The saturated and
unsaturated alkyl chains can have from 5 to 24 carbon atoms.
Desirably, the alkyl chains have from 6 to 18 carbon atoms and,
more desirably, the alkyl chains have from 8 to 16 carbon atoms.
The hydrophobic side chains can be bonded to a hydrophilic backbone
of the decoupling polymers by an alkoxylene or a polyalkoxylene
linkage, such as a polyethoxy, polypropoxy, butyloxy or mixed
linkage having from 1 to 50 alkoxylene groups. Additionally, the
hydrophobic side chains can be selected from relatively hydrophobic
alkoxy groups such as butylene oxide and propylene oxide. In such
cases, the hydrophobic side chains have the character of a nonionic
surfactant. Additional examples of suitable decoupling polymers are
described in U.S. Pat. No. 5,147,576 issued to Montague et al., the
disclosure of which is incorporated by reference herein.
[0028] The compositions of the invention can also include from
about 0.1 to about 95 percent by weight of natural fats or natural
oils. More specifically, the compositions can include from about 5
to about 75 percent by weight of natural fats or natural oils.
Desirably, the compositions of the invention include from about 10
to about 50 percent by weight of natural fats, natural oils or
mixtures of both. Natural fats and oils include fats, oils,
essential oils, fatty acids, fatty alcohols, phospholipids and
mixtures of these compounds. The natural fats and oils can be
similar to the lipids that are present in healthy skin in order to
mimic the naturally present lipids. Synthetic or synthetically
modified fats and oils could potentially also be used if they
functioned in the same manner as their natural counterparts.
Examples of fats and oils include Avocado Oil, Apricot Oil, Babassu
Oil, Borage Oil, Camellia Oil, Canola Oil, Castor Oil, Coconut Oil,
Corn Oil, Cottonseed Oil, Evening Primrose Oil, Hydrogenated
Cottonseed Oil, Hydrogenated Palm Kernel Oil, Maleated Soybean Oil,
Meadowfoam Oil, Palm Kernel Oil, Peanut Oil, Rapeseed Oil,
Safflower Oil, Sphingolipids, Sweet Almond Oil, Tall Oil, Lanolin,
Lanolin Alcohol, Lauric Acid, Palmitic Acid, Stearic Acid, Linoleic
Acid, Stearyl Alcohol, Lauryl Alcohol, Myristyl Alcohol, Behenyl
Alcohol, Rose Hip Oil, Calendula Oil, Chamomile Oil, Eucalyptus
Oil, Juniper Oil, Sandlewood Oil, Tea Tree Oil, Sunflower Oil,
Soybean Oil and mixtures thereof.
[0029] The compositions can also include sterols, sterol
derivatives or mixtures of both in an amount of from about 0.1 to
about 10 percent by weight. Sterols and sterol derivatives include
compounds such as .beta.-sterols with a tail on the 17 position and
no polar groups, such as cholesterol, C.sub.10-C.sub.30
cholesterol/lanosterol esters, tall oil sterols, soy sterols,
sterol esters and mixtures of these compounds. More specifically,
the compositions include from about 0.5 to about 5 percent by
weight of sterols, sterol derivatives or mixtures of both. Even
more specifically, the compositions include from about 0.8 to about
1 percent by weight of the sterol compounds. Examples of suitable
sterol compounds include cholesterol, sitosterol, stigmasterol, and
ergosterol, as well as, C.sub.10-C.sub.30 cholesterol/lanosterol
esters, cholecalciferol, cholesteryl hydroxystearate, cholesteryl
isostearate, cholesteryl stearate, 7-dehydrocholesterol,
dihydrocholesterol, dihydrocholesteryl octyldecanoate,
dihydrolanosterol, dihydrolanosteryl octyldecanoate,
ergocalciferol, tall oil sterol, soy sterol acetate, lanasterol,
soy sterol, avocado sterols, "AVOCADIN" (available from Croda Ltd.
of Parsippany, N.J.), sterol esters and mixtures thereof.
[0030] In addition to one or more viscosity enhancers, the
compositions of the invention may also include one or more rheology
modifiers. Rheology modifiers are compounds that increase the
viscosity of the compositions at lower temperatures as well as
process temperatures. Rheology modifiers or suspending agents also
provide "structure" to the compositions to prevent settling out
(separation) of insoluble and partially soluble components. Other
components or additives of the compositions may effect the
temperature viscosities/rheologies of the compositions. By
increasing the viscosity at process temperatures, the rheology
modifiers will increase the low shear viscosity above 50,000
centipoise. However, the rheology modifiers are thixotropic in
behavior; therefore, their viscosity decreases as shear and
pressure increases. Consequently, when the rheology modifiers are
used in the compositions of the invention, they maintain the
suspension of insoluble and partially soluble components. This
capability can be particularly important if, during processing, the
composition must be left stagnant in process lines and hoses. The
rheology modifiers will maintain the suspension of the insoluble
and partially soluble components for a period of time that depends
on the viscosity of the composition and on the amount of rheology
modifier present. The thixotropic behavior of the rheology
modifiers causes their viscosity to drop when processing is resumed
and the composition is no longer stagnant due to the application of
pressure and shear forces. In addition to stabilizing the
suspension of insoluble and partially soluble components, the
rheology modifiers of the invention also help to stabilize the
compositions on the bodyfacing or other materials to which the
compositions are applied. Examples of suitable rheology modifiers
include silica, silica silylate, silica methyl silylate, quaternary
starch compounds, quaternary modified clays, organically modified
clays and mixtures thereof. Such rheology modifiers can help
maintain the suspension of an insoluble emollient, such as a
siloxane, or particulates such as microencapsulates, anionic
polymers, clays and inorganic materials, within the composition.
The compositions of the invention can include from about 0.5 to
about 20 percent by weight of one or more rheology modifiers.
[0031] The use of a rheology modifier or more than one rheology
modifier, such as an organically modified clay in combination with
a silica, can provide a benefit to the rheology of the compositions
of the invention by increasing the viscosity of the compositions at
process temperatures. When a silica, an organically modified clay
or both are used in an ointment or lotion type composition, it is
expected that they will increase the hardness of the composition
and, consequently, have a potentially negative effect on transfer
of the ointment to the skin. However, when a natural clay or a
synthetic analog of a natural clay is used in combination with an
organically modified clay or a silica, there is an unexpected,
synergistic enhancement of the rheology of the composition. The
organically modified clay and silica assist the suspension of the
natural clay/synthetic analog of a natural clay in the compositions
of the invention. While the penetration hardness of the composition
increases, the transfer of the composition is not affected due to
rheology enhancement and, in many instances, the transfer is
increased. When a natural clay or synthetic analog of a natural
clay is combined with an organically modified clay or a silica, a
small amount of shear (such as rubbing) will unexpectedly cause the
composition to become soft and to spread easily. Therefore, when
such a combination is used in the compositions of the invention,
there is an improvement in the transfer of the composition from the
bodyside liner of the article to the skin. Though these
compositions provide improved transfer from the liner to the skin,
they remain stable on the bodyside liner under storage conditions.
Natural clays include montmorillonite, bentonite, beidellite,
hectorite, saponite, stevensite, magnesium aluminum silicate and
similar clays. Synthetic analogs of natural clays, such as LAPONITE
synthetic clay available from Southern Clay Products, Inc. of
Gonzales, Texas can also be used to provide the rheology benefit to
compositions of the invention when used in combination with
organically modified clays or silica.
[0032] Sometimes it is necessary for the compositions of the
invention to include additional components that can be used to
emulsify the decoupling polymer with the rest of the composition,
particularly if the polymer is solubilized in water or a glycol. If
such decoupling polymers are not properly incorporated into the
composition, they may not have the bioavailability to provide
benefits to the skin. In addition to modifications to the
formulation, some decoupling polymers can also be better
incorporated through the use of processing techniques. For
compositions of the invention including decoupling polymers that
are solubilized in water or a glycol, it may be necessary to add an
emulsifying agent such as an emulsifier having an HLB less than 7.
An appropriate emulsifying agent is ABIL EM90 emulsifier available
from Goldschmidt AG of Germany. Other appropriate emulsifiers
include sorbitan monooleate, sorbitan sesquioleate, sorbitan
trioleate and glycerol monooleate. The polymers can also be better
incorporated into the composition by using high shear in processing
or a suitable rheology modifier. Another option for dispersing a
polmyer is to first blend the polymer with a hydrophilic solvent
such as water, propylene glycol, butylene glycol or glycerol.
Dispersing the polymer in a hydrophilic solvent and using an
emulsifying agent to incorporate the solvent into the remainder of
the composition provides the polymer in a "bioavailable" form in
which it can contribute to protecting the skin barrier and subduing
the inflammatory response of the skin.
[0033] For the reasons described above, emulsifiers, particularly
those of HLB below 7, may be useful for purposes of the present
invention at levels to from about 0.1 to about 10 percent by
weight. Suitable emulsifiers include alkoxylated C.sub.8-C.sub.30
fatty acids and fatty alcohols. Examples of such emulsifiers are
polyoxyethylene (2) lauryl ether, polyoxyethylene (3) monostearate,
polyoxyethylene (6) cetyl ether and polyoxyethylene (5) stearyl
ether and Myreth-3-Myristate (CTFA name) available commercially as
"Cetiol 1414-E.RTM.". Other suitable emulsifiers included cetyl
phosphate salts and dimethicone copolyol, the latter commercially
available as ABIL EM90 emulsifier from Goldschmidt AG of Germany.
Phosphatides such as lecithin may also be useful as emulsifiers in
the compositions of the invention.
[0034] As will be described later in further detail, the
compositions of the invention are suspected to improve the health
of skin frequently occluded by absorbent articles through several
mechanisms. A potential mechanism is the inhibition of enzymes
present in the various forms of biological insults, namely
proteases and lipases. Through inhibition of such enzymes, the
compositions can protect the skin barrier by "deactivating" those
substances that can deteriorate the skin barrier. Another mechanism
of action is believed to be interaction of the compositions with
the stratum corneum to provide a protective barrier against
irritant entrance. A further mechanism of action is believed to be
a subduing of the inflammatory response of the skin.
[0035] In addition to the components already described, the
compositions of the invention may also include active ingredients
such as those ingredients that may be useful for treating skin
irritations such as diaper rash. Examples of such active
ingredients include allantoin and its derivatives, aloe, aluminum
hydroxide gel, calamine, cocoa butter, cod liver oil, dimethicone,
glycerin, kaolin and its derivatives, lanolin and its derivatives,
mineral oil, petrolatum, white petrolatum, shark liver oil, talc,
topical starch, zinc acetate, zinc carbonate, zinc oxide and
mixtures of these ingredients. Some of the ingredients listed as
possible active ingredients for treating the skin can also be used
as emollients.
[0036] In order to enhance or increase the function of the
compositions of the invention, additional ingredients may be added.
Examples of the classes of ingredients along with their functions
include: antifoaming agents (reduce the tendency of foaming during
processing); antimicrobial actives; antifungal actives; antiseptic
actives; antioxidants (product integrity); antioxidants-cosmetic
(reduce oxidation); astringents-cosmetic (induce a tightening or
tingling sensation on skin); astringent-drug (a drug product that
checks oozing, discharge, or bleeding when applied to skin or
mucous membrane and works by coagulating protein); biological
additives (enhance the performance or consumer appeal of the
product); colorants (impart color to the product); deodorants
(reduce or eliminate unpleasant odor and protect against the
formation of malodor on body surfaces); other emollients (help to
maintain the soft, smooth, and pliable appearance of the skin by
their ability to remain on the skin surface or in the stratum
corneum to act as lubricants, to reduce flaking, and to improve the
skin's appearance); external analgesics (a topically applied drug
that has a topical analgesic, anesthetic, or antipruritic effect by
depressing cutaneous sensory receptors, or that has a topical
counterirritant effect by stimulating cutaneous sensory receptors);
film formers (to hold active ingredients on the skin by producing a
continuous film on skin upon drying); fragrances (consumer appeal);
silicones/organomodified silicones (protection, water resistance,
lubricity, softness); oils (mineral, vegetable, and animal);
natural moisturizing agents (NMF) and other skin moisturizing
ingredients known in the art; opacifiers (reduce the clarity or
transparent appearance of the product); powders (enhance lubricity,
oil adsorption, provide skin protection, astringency, opacity,
etc.); skin conditioning agents; solvents (liquids employed to
dissolve components found useful in the cosmetics or drugs); and
surfactants (as cleansing agents, emulsifying agents, solubilizing
agents, and suspending agents).
[0037] Ranges are used to describe the relative quantities of
compounds in the compositions of the invention and ranges are used
to describe the relative physical properties of the compositions of
the invention. It is understood that the ranges are by way of
illustration only and that one of skill in the art would recognize
that the nature of the specific compositions dictates the levels to
be applied to achieve the desired results. The levels of components
are ascertainable by routine experimentation in view of the present
disclosure.
[0038] The compositions of the invention typically have a melting
point of from about 32.degree. C. to about 100.degree. C. Melting
behavior in this range provides compositions that are relatively
immobile and localized on the bodyfacing surface of the bodyside
liner of the absorbent article at room temperature. Though
relatively immobile and localized at room temperature, the
compositions are also readily transferable to the wearer of the
article at body temperature through natural rubbing or friction
during wearing and through adhesion of the composition to the skin
of the wearer. The compositions also maintain their integrity and
are not completely liquid at elevated temperatures such as may be
experienced during storage. Stability in a solid state at elevated
temperatures is made possible, in part, by the increase in
viscosity provided by the viscosity enhancers. Desirably, the
compositions of the invention are easily transferable to the skin
by way of normal contact, including adhesion of the composition to
the skin, wearer motion or body heat. Because the compositions are
relatively immobilized on the bodyfacing surfaces of the articles,
the quantities of the compositions necessary to provide the desired
skin barrier benefits are reduced. In addition, special barrier or
wrapping materials may not be necessary for the articles of the
invention.
[0039] The compositions of the invention have high shear
viscosities of less than about 5,000 centipoise at processing
temperatures such as at a temperature of about 60.degree. C. or
higher. The melting points and, therefore, the processing
temperatures vary for different compositions of the invention. At
about 55.degree. C. or less, the compositions have low shear
viscosities greater than about 50,000 centipoise. The compositions
may also have a penetration hardness of from about 5 millimeters to
about 365 millimeters at 25.degree. C.
[0040] In addition to the articles and compositions already
described, the present invention is also directed to absorbent
articles that include an outer cover, a liquid permeable bodyside
liner, an absorbent body and a composition on at least a portion of
the bodyside liner. The bodyside liner defines a bodyfacing surface
and the bodyside liner is connected in superposed relation to the
outer cover. The absorbent body is located between the bodyside
liner and the outer cover. The composition is on at least a portion
of the bodyfacing surface of the bodyside liner.
[0041] The composition can include from about 0.1 to about 95
percent by weight of natural fats or oils. The natural fats and
oils may be selected from avocado oil, borage oil, sunflower oil,
soybean oil, corn oil, cottonseed oil and mixtures of such fats and
oils. The composition can also include from about 0.1 to about 10
percent by weight of sterols and sterol derivatives. The sterols
and sterol derivatives may be selected from cholesterol,
sitosterol, stigmasterol, tall oil sterol, soy sterol and mixtures
of such sterols. Additionally, the composition can include from
about 1 to about 95 percent by weight of one or more emollients.
The emollients may be selected from petrolatum, silicone oils,
dimethicone, esters, hydrogenated vegetable/animal oils,
triglycerides, glycerol esters, propylene glycol esters,
alkoxylated alcohols, alkoxylated carboxylic acid, lanolin and
mixtures of such emollients. The composition can also include from
about 5 to about 95 percent by weight of one or more solidifying
agents. The solidifying agents may be selected from alkyl
silicones, beeswax, behenyl behenate, behenyl benzoate,
C.sub.24-C.sub.28 alkyl dimethicone, C.sub.30 alkyl dimethicone,
cetyl methicone, stearyl methicone, cetyl dimethicone, stearyl
dimethicone, cerotyl dimethicone, candelilla wax, carnauba,
cerasin, hydrogenated microcrystalline wax, jojoba wax,
microcrystalline wax, lanolin wax, ozokerite, paraffin, cetyl
esters and mixtures of such solidifying agents. The composition
further includes from about 0 1 to about 40 percent by weight of
one or more viscosity enhancers. The viscosity enhancers may be
selected from ethylene/vinyl acetate copolymers, organically
modified clays, polyethylene, silica and mixtures of such viscosity
enhancers. The composition also includes from about 0.1 to about 20
percent by weight of one or more decoupling polymers. The
decoupling polymers may be selected from homopolymers of acrylic
acid, acrylic acid/maleic acid copolymers, poly(2-hydroxy ethyl
acrylate), polysaccharides, cellulose ethers, polyglycerols,
polyacrylamides, polyvinylalcohol/polyvinylether copolymers,
poly(sodium vinyl sulphonate), poly(2-sulphato ethyl methacrylate)
and poly(acrylamidomethylpropane sulphonate) and mixtures of such
decoupling polymers. The composition may also include a rheology
modifier and a natural clay or synthetic analog of a natural clay
to provide a rheological benefit.
[0042] The articles with respect to this aspect of the invention
may have compositions on at least a portion of the bodyfacing
surface of the bodyside liner in which the compositions may have
certain physical properties. For example, the compositions may have
melting points of from about 32.degree. C. to about 100.degree. C.
such that the compositions are relatively immobile on the
bodyfacing surface at room temperature but are readily transferable
to the skin at body temperature. The compositions may also have
viscosities less than about 5,000 centipoise at temperatures of
about 60.degree. C. and higher and viscosities greater than about
50,000 centipoise at temperatures of about 55.degree. C. and lower.
Additionally, the compositions may have a penetration hardness of
from about 5 millimeters to about 365 millimeters at 25.degree. C.
The compositions may be applied to at least a portion of the
bodyfacing surface in an amount of from about 0.1 grams per meter
squared (g/m.sup.2) to about 30 g/m.sup.2. Those of skill in the
art will know how to modify the components and attributes of the
compositions encompassed by the invention to achieve the desired
benefits to the skin barrier and reduction in inflammatory response
of the skin based on the disclosure provided herein.
[0043] The present invention is further directed to a method of
applying a composition to a bodyfacing surface of a bodyside liner
of an absorbent article. The method of the invention includes a
step of heating a composition to a temperature above the melting
point of the composition. The composition can have a melting point
of from about 32.degree. C. to about 100.degree. C. The composition
can include an emollient, a viscosity enhancer and a decoupling
polymer. The composition can also include fats and oils, sterols or
sterol derivatives, solidifying agents, rheology modifiers or
clays. The method further includes a step of applying the
composition to the bodyfacing surface of a bodyside liner of an
absorbent article. The bodyfacing surface is that surface of the
absorbent article that comes into contact with the skin of the
wearer of the absorbent article. Other components of the absorbent
article besides the bodyside liner may come into contact with the
skin of the wearer. The composition can also be applied to those
components including the waist elastics, the leg elastics,
containment flaps and any other components coming into contact with
the skin.
[0044] The composition can be applied to the bodyfacing surface
using a variety of techniques including foam application, spraying,
slot coating, printing or combinations of these application
techniques. The method of the invention also includes a step of
resolidifying the composition. The composition can be resolidified
in a variety of ways including chilling, slow cooling, curing or a
combination of these techniques. Further, the composition can have
a penetration hardness of from about 5 to about 365 millimeters at
25.degree. C. after the step of resolidification.
[0045] In an additional aspect, the present invention is directed
to a method for protecting the skin barrier on a skin surface of a
user. The method can include a step of contacting the skin surface
of a user with a bodyfacing surface of a liner material. The liner
material may be any type of woven or non-woven material. More
specifically, the liner material is of a material that is typically
used for the bodyside liner of an absorbent article. The bodyfacing
surface of the liner material has a composition on it. The
composition can include an emollient, a viscosity enhancer and a
decoupling polymer. More specifically, the composition can include
from about 40 to about 95 percent by weight of emollients, from
about 1 to about 40 percent by weight of viscosity enhancers and
from about 0.1 to about 20 percent by weight of decoupling
polymers.
[0046] The method can also include a step of maintaining the
bodyfacing surface of the liner material in contact with the skin
surface of a user for a sufficient amount of time to transfer the
composition to the skin surface. For purposes of the method, a
sufficient amount of time would be the amount of time necessary for
enough of the composition to have been transferred so as to benefit
the skin barrier. The method of the invention further includes a
step of repeating contact of the skin surface with the bodyfacing
surface of the liner material for a sufficient amount of time in
order to provide a benefit to the skin barrier function of the
wearer's skin. The repeated contact can occur by either applying
additional composition to the bodyfacing surface of the liner
material or by applying a new liner material having a full amount
of the composition on the bodyfacing surface.
[0047] The absorbent articles, methods and compositions of the
invention advantageously protect the skin barrier and subdue
inflammation in such a way not observed with conventional absorbent
articles and compositions. Consequently, use of the absorbent
articles and compositions of the invention protect the skin barrier
against damage caused by physical and biological irritations. It is
to be understood that both the foregoing general description and
the following detailed description are exemplary and are intended
to provide further explanation of the invention claimed. The
accompanying drawings, that are incorporated in and constitute part
of this specification, are included to illustrate and provide a
further understanding of the articles, methods and compositions of
the invention. Together with the description, the drawings serve to
explain the various aspects of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] The present invention will be more fully understood and
further advantages will become apparent when reference is made to
the following detailed description of the invention and the
accompanying drawings. The drawings are merely representative and
are not intended to limit the scope of the claims. Like parts of
the absorbent articles depicted in the drawings are referred to by
the same reference numerals.
[0049] FIG. 1 representatively shows a partially cut away, top plan
view of an absorbent article according to one aspect of the
invention in a stretched and laid flat condition with the surface
of the article that contacts the skin of the wearer facing the
viewer;
[0050] FIG. 2 representatively shows a sectional view of the
absorbent article of FIG. 1 taken along line 2--2; and
[0051] FIG. 3 representatively shows a top plan view of the
bodyside liner of the absorbent article of FIG. 1 with the surface
that contacts the wearer facing the viewer.
[0052] FIG. 4 graphically represents the relationship between
transfer amount and penetration hardness for compositions of the
invention and previously known compositions.
[0053] FIG. 5 graphically represents the relationship between
viscosity and shear rate for compositions of the invention and
previously known compositions.
[0054] FIG. 6 graphically represents the relationship between
viscosity and shear rate for compositions of the invention and
previously known compositions.
DETAILED DESCRIPTION OF THE INVENTION
[0055] The present invention is directed to solving problems
related to protecting the skin barrier and subduing inflammatory
response when the skin is exposed to causes of physical and
biological damage. Similarly, the present invention is directed to
solving problems related to the prevention and treatment of diaper
rash.
[0056] The present disclosure of the invention will be expressed in
terms of its various components, elements, constructions,
configurations, arrangements and other features that may also be
individually or collectively referenced by the term, "aspect(s)" of
the invention, or other similar terms. It is contemplated that the
various forms of the disclosed invention may incorporate one or
more of its various features and aspects, and that such features
and aspects may be employed in any desired, operative combination
thereof.
[0057] It should also be noted that when employed in the present
disclosure, the terms "comprises", "comprising" and other
derivatives from the root term "comprise" are intended to be
open-ended terms that specify the presence of any stated features,
elements, integers, steps, or components, and are not intended to
preclude the presence or addition of one or more other features,
elements, integers, steps, components or groups thereof.
[0058] The present invention encompasses compositions, compositions
as they are applied to the bodyfacing materials of absorbent
articles, absorbent articles including compositions and methods of
applying compositions to absorbent articles. The following detailed
description will be made in the context of one type of absorbent
article, a disposable diaper that is adapted to be worn by infants
about their lower torso. It is readily apparent, however, that the
absorbent article of the present invention would also be suitable
for use as another type of absorbent article, such as a feminine
care pad, an incontinence garment, a training pant, a prefastened
or refastenable diaper pant, a wound dressing or a nursing pad.
Further, the compositions of the invention are not limited to
application on the bodyfacing materials of absorbent articles. For
example, the compositions of the inventions could be used on
skin-contacting substrates such as tissues, wet (pre-moistened)
wipe materials and cosmetic pads (such as for cleansing or
buffing).
[0059] FIG. 1 is a representative plan view of a disposable diaper
10 of the present invention in a flat-out, uncontracted state
(i.e., with all elastic induced gathering and contraction removed).
The bodyfacing surface 11 of the diaper 10, that is, the surface 11
of the diaper 10 that contacts the wearer is facing the viewer. The
compositions of the invention can be applied to one or more
bodyfacing materials that are components of the diaper 10. As used
herein, the term `bodyfacing material` includes, but is not limited
to, materials such as the bodyside liner or topsheet, elastic
material, tissue, intake and distribution material, absorbent
material, and backsheet material. Each of these materials and
components of a diaper 10 are described more fully herein. The
compositions of the invention are applied to one or more of the
bodyfacing materials in order to have a beneficial effect on the
skin barrier. The bodyfacing material of the present invention can
be a single layer or multi-layered.
[0060] With reference to FIG. 1, the diaper 10 generally defines a
front waist section 12, a rear waist section 14, and an
intermediate section 16 that interconnects the front and rear waist
sections 12 and 14. The front and rear waist sections 12 and 14
include the general portions of the diaper 10 that are constructed
to extend substantially over the wearer's front and rear abdominal
regions, respectively, during use. The intermediate section 16 of
the diaper 10 includes the general portion of the diaper 10 that is
constructed to extend through the wearer's crotch region between
the legs.
[0061] The diaper 10 includes a vapor permeable backsheet or outer
cover 20, a liquid permeable topsheet or bodyside liner 22
positioned in facing relation with the outer cover 20, and an
absorbent body 24, such as an absorbent pad, which is located
between the outer cover 20 and the bodyside liner 22. The outer
cover 20 defines a length and a width that, in the illustrated
aspect, coincide with the length and width of the diaper 10. The
absorbent body 24 generally defines a length and width that are
less than the length and width of the outer cover 20, respectively.
Thus, marginal portions of the diaper 10, such as marginal sections
of the outer cover 20, may extend past the terminal edges of the
absorbent body 24. In the illustrated aspects, for example, the
outer cover 20 extends outwardly beyond the terminal marginal edges
of the absorbent body 24 to form side margins and end margins of
the diaper 10. The bodyside liner 22 is generally coextensive with
the outer cover 20 but may optionally cover an area that is larger
or smaller than the area of the outer cover 20, as desired. In
other words, the bodyside liner 22 is connected in superposed
relation to the outer cover 20. The outer cover 20 and bodyside
liner 22 are intended to face the garment and body of the wearer,
respectively, while in use.
[0062] To provide improved fit and to help reduce leakage of body
exudates from the diaper 10, the diaper side margins and end
margins may be elasticized with suitable elastic members, such as
single or multiple strands of elastic. The elastic strands may be
composed of natural or synthetic rubber and may optionally be heat
shrinkable or heat elasticizable. For example, as representatively
illustrated in FIG. 1, the diaper 10 may include leg elastics 26
which are constructed to operably gather and shirr the side margins
of the diaper 10 to provide elasticized leg bands which can closely
fit around the legs of the wearer to reduce leakage and provide
improved comfort and appearance. Similarly, waist elastics 28 can
be employed to elasticize the end margins of the diaper 10 to
provide elasticized waists. The waist elastics 28 are configured to
operably gather and shirr the waist sections to provide a
resilient, comfortably close fit around the waist of the wearer. In
the illustrated aspects, the elastic members are illustrated in
their uncontracted, stretched condition for the purpose of
clarity.
[0063] Fastening means, such as hook and loop fasteners 30, are
employed to secure the diaper 10 on a wearer. Alternatively, other
fastening means, such as buttons, pins, snaps, adhesive tape
fasteners, cohesives, mushroom-and-loop fasteners, or the like, may
be employed. Additionally, more than two fasteners can be provided,
particularly if the diaper 10 is to be provided in a prefastened
configuration. The fasteners can vary in size and form.
[0064] The diaper 10 may further include other layers between the
absorbent body 24 and the bodyside liner 22 or outer cover 20. For
example, as representatively illustrated in FIGS. 1 and 2, the
diaper 10 may include a ventilation layer 32 located between the
absorbent body 24 and the outer cover 20 to insulate the outer
cover 20 from the absorbent body 24, to improve air circulation and
to effectively reduce the dampness of the garment facing surface of
the outer cover 20. The ventilation layer 32 may also assist in
distributing fluid exudates to portions of the absorbent body 24
that do not directly receive the insult. The diaper 10 may also
include a surge management layer 34 located between the bodyside
liner 22 and the absorbent body 24 to prevent pooling of the fluid
exudates and further improve air exchange and distribution of the
fluid exudates within the diaper 10.
[0065] The diaper 10 may be of various suitable shapes. For
example, the diaper may have an overall rectangular shape, T-shape
or an approximately hourglass shape. In the shown aspect, the
diaper 10 has a generally I-shape. The diaper 10 further defines a
longitudinal direction 36 and a lateral direction 38. Other
suitable diaper components that may be incorporated on absorbent
articles of the present invention include containment flaps, waist
flaps, elastomeric side panels, and the like which are generally
known to those skilled in the art. Likewise, if the diaper 10 is to
be sold in a prefastened condition, the diaper 10 may have passive
bonds (not shown) that join the rear waist section 14 with the
front waist section 12.
[0066] Examples of diaper configurations suitable for use in
connection with the instant application that may include other
diaper components suitable for use on diapers are described in U.S.
Pat. No. 4,798,603 issued Jan. 17, 1989, to Meyer et al.; U.S. Pat.
No. 5,176,668 issued Jan. 5, 1993, to Bernardin; U.S. Pat. No.
5,176,672 issued Jan. 5, 1993, to Bruemmer et al.; U.S. Pat. No.
5,192,606 issued Mar. 9, 1993, to Proxmire et al., and U.S. Pat.
No. 5,509,915 issued Apr. 23, 1996 to Hanson et al., the
disclosures of which are herein incorporated by reference.
[0067] The various components of the diaper 10 are integrally
assembled together employing various types of suitable attachment
means, such as adhesive, sonic bonds, thermal bonds or combinations
thereof. In the shown aspect, for example, the bodyside liner 22
and outer cover 20 are assembled to each other and to the absorbent
body 24 with lines of adhesive, such as a hot melt,
pressure-sensitive adhesive. Similarly. other diaper components,
such as the elastic members 26 and 28, fastening members 30, and
ventilation and surge layers 32 and 34 may be assembled into the
diaper 10 by employing the above-identified attachment
mechanisms.
[0068] The outer cover 20 of the diaper 10, as representatively
illustrated in FIG. 1, is composed of a substantially vapor
permeable material. The permeability of the outer cover 20 is
configured to enhance the breathability of the diaper 10 and to
reduce the hydration of the wearer's skin during use without
allowing excessive condensation of vapor, such as urine, on the
garment facing surface of the outer cover 20 that can undesirably
dampen the wearer's clothes. The outer cover 20 is generally
constructed to be permeable to at least water vapor and has a water
vapor transmission rate of at least about 1000 g/m.sup.2/24 hr.,
desirably at least about 1500 g/m.sup.2/24 hr, more desirably at
least about 2000 g/m.sup.2/24 hr., and even more desirably at least
about 3000 g/m.sup.2/24 hr. For example, the outer cover 20 may
define a water vapor transmission rate of from about 1000 to about
6000 g/m.sup.2/24 hr. Materials that have a water vapor
transmission rate less than those above do not allow a sufficient
amount of air exchange and undesirably result in increased levels
of skin hydration.
[0069] The outer cover 20 is also desirably substantially liquid
impermeable. For example, the outer cover 20 may be constructed to
provide a hydrohead value of at least about 60 cm, desirably at
least about 80 cm, and more desirably at least about 100 cm when
subjected to the Hydrostatic Pressure Test. Materials that have
hydrohead values less than those above undesirably result in the
strike through of liquids, such as urine, during use. Such fluid
strike through can undesirably result in a damp, clammy feeling on
the outer cover 20 during use.
[0070] The outer cover 20 may be composed of any suitable materials
that either directly provide the above desired levels of liquid
impermeability and air permeability or, in the alternative,
materials that can be modified or treated in some manner to provide
such levels. In one aspect, the outer cover 20 may be a nonwoven
fibrous web constructed to provide the required level of liquid
impermeability. For example, a nonwoven web composed of spunbond or
meltblown polymer fibers may be selectively treated with a water
repellent coating or laminated with a liquid impermeable, vapor
permeable polymer film to provide the outer cover 20. In a
particular aspect of the invention, the outer cover 20 may include
a nonwoven web composed of a plurality of randomly deposited
hydrophobic thermoplastic meltblown fibers that are sufficiently
bonded or otherwise connected to one another to provide a
substantially vapor permeable and substantially liquid impermeable
web. The outer cover 20 may also include a vapor permeable nonwoven
layer that has been partially coated or otherwise configured to
provide liquid impermeability in selected areas.
[0071] Examples of suitable materials for the outer cover 20 are
also described in U.S. Pat. No. 5,482,765 issued Jan. 9, 1996 in
the name of Bradley et al. and entitled "NONWOVEN FABRIC LAMINATE
WITH ENHANCED BARRIER PROPERTIES"; U.S. Pat. No. 5,879,341 issued
Mar. 9, 1999 in the name of Odorzynski et al. and entitled
"ABSORBENT ARTICLE HAVING A BREATHABILITY GRADIENT"; U.S. Pat. No.
5,843,056 issued Dec. 1, 1998, in the name of Good et al. and
entitled "ABSORBENT ARTICLE HAVING A COMPOSITE BREATHABLE
BACKSHEET"; and U.S. patent application Ser. No. 08/882,712 filed
Jun. 25, 1997, in the name of McCormack et al. and entitled "LOW
GAUGE FILMS AND FILM/NONWOVEN LAMINATES", the disclosures of which
are herein incorporated by reference.
[0072] In a particular aspect, the outer cover 20 is provided by a
microporous film/nonwoven laminate material that includes a
spunbond nonwoven material laminated to a microporous film. The
spunbond nonwoven comprises filaments of about 1.8 denier extruded
from a copolymer of ethylene with about 3.5 weight percent
propylene and defines a basis weight of from about 17 to about 25
grams per square meter. The film comprises a cast coextruded film
having calcium carbonate particles therein and defines a basis
weight of about 58 grams per square meter prior to stretching. The
film is preheated, stretched and annealed to form the micropores
and then laminated to the spunbond nonwoven. The resulting
microporous film/nonwoven laminate based material has a basis
weight of from about 30 to about 60 grams per square meter and a
water vapor transmission rate of from about 3000 to about 6000
g/m.sup.2/24 hr. Examples of such film/nonwoven laminate materials
are described in more detail in U.S. patent application Ser. No.
08/882,712 filed Jun. 25, 1997, in the name of McCormack et al. and
entitled "LOW GAUGE FILMS AND FILM/NONWOVEN LAMINATES", the
disclosure of which has been incorporated by reference.
[0073] In another aspect, the outer cover 20 is provided by an
extensible material. Further, the outer cover 20 can also be
provided by a material having stretch in both the longitudinal 36
and lateral 38 directions. Extensible and stretchable outer cover
materials can be used in absorbent articles to provide various
benefits including better fitting articles.
[0074] The bodyside liner 22, as representatively illustrated in
FIGS. 1 and 2, defines a bodyfacing surfacel 1 that is compliant,
soft feeling. and nonirritating to the wearer's skin. Further, the
bodyside liner 22 may be less hydrophilic than the absorbent body
24, to present a relatively dry surface to the wearer, and may be
sufficiently porous to be liquid permeable, permitting liquid to
readily penetrate through its thickness. A suitable bodyside liner
22 may be manufactured from a wide selection of web materials, such
as porous foams, reticulated foams, apertured plastic films,
natural fibers (for example, wood or cotton fibers), synthetic
fibers (for example, polyester or polypropylene fibers), or a
combination of natural and synthetic fibers. The bodyside liner 22
is suitably employed to help isolate the wearer's skin from liquids
held in the absorbent body 24.
[0075] Various woven and nonwoven fabrics can be used for the
bodyside liner 22. For example, the bodyside liner 22 may be
composed of a meltblown or spunbond web of polyolefin fibers. The
bodyside liner 22 may also be a bonded-carded web composed of
natural and/or synthetic fibers. The bodyside liner 22 may be
composed of a substantially hydrophobic material, and the
hydrophobic material may, optionally, be treated with a surfactant
or otherwise processed to impart a desired level of wettability and
hydrophilicity. In a particular aspect of the present invention,
the bodyside liner 22 comprises a nonwoven, spunbond, polypropylene
fabric composed of about 2.8-3.2 denier fibers formed into a web
having a basis weight of about 22 grams per square meter and a
density of about 0.06 gram per cubic centimeter.
[0076] In a particular aspect of the present invention, the
bodyside liner 22 may be surface treated with about 0.3 weight
percent of a surfactant mixture that contains a mixture of AHCOVEL
Base N-62 and GLUCOPON 220UP surfactants in about a 3:1 ratio based
on a total weight of the surfactant mixture. The AHCOVEL Base N-62
surfactant is purchased from Hodgson Textile Chemicals Inc., a
business having offices in Mount Holly, N.C., and includes a blend
of hydrogenated ethoxylated castor oil and sorbitan monooleate in a
55:45 weight ratio. The GLUCOPON 220UP surfactant is purchased from
Henkel Corporation and includes alkyl polyglycoside. The surfactant
may also include additional ingredients such as aloe. The
surfactant may be applied by any conventional means, such as
spraying, printing, brush coating, foam or the like. The surfactant
may be applied to the entire bodyside liner 22 or may be
selectively applied to particular sections of the bodyside liner
22, such as the medial section along the longitudinal centerline of
the diaper, to provide greater wettability of such sections.
[0077] The absorbent body 24 of the diaper 10, as representatively
illustrated in FIG. 1, may suitably comprise a matrix of
hydrophilic fibers, such as a web of cellulosic fluff, mixed with
particles of a high-absorbency material commonly known as
superabsorbent material. In a particular aspect, the absorbent body
24 includes a matrix of cellulosic fluff, such as wood pulp fluff,
and superabsorbent hydrogel-forming particles. The wood pulp fluff
may be exchanged with synthetic, polymeric, meltblown fibers or
with a combination of meltblown fibers and natural fibers. The
superabsorbent particles may be substantially homogeneously mixed
with the hydrophilic fibers or may be nonuniformly mixed.
Alternatively, the absorbent body 24 may include a laminate of
fibrous webs and superabsorbent material or other suitable matrix
for maintaining a superabsorbent material in a localized area.
[0078] The absorbent body 24 may have any of a number of shapes.
For example, the absorbent body 24 may be rectangular, I-shaped, or
T-shaped. It is generally preferred that the absorbent body 24 is
narrower in the intermediate section than in the front or rear
waist sections of the diaper 10. The absorbent body 24 may be
provided by a single layer or, in the alternative, may be provided
by multiple layers, all of which need not extend the entire length
and width of the absorbent body 24. In a particular aspect of the
invention, the absorbent body 24 can be generally T-shaped with the
laterally extending cross-bar of the "T" generally corresponding to
the front waist section 12 of the absorbent article for improved
performance, especially for male infants. In the illustrated
aspects, for example, the absorbent body 24 across the front waist
section 12 of the article has a cross-directional width of about 18
centimeters, the narrowest portion of the intermediate section 16
has a width of about 7.5 centimeters and in the rear waist section
14 has a width of about 11.4 centimeters.
[0079] The size and the absorbent capacity of absorbent body 24
should be compatible with the size of the intended wearer and the
liquid loading imparted by the intended use of the absorbent
article. Further, the size and the absorbent capacity of the
absorbent body 24 can be varied to accommodate wearers ranging from
infants through adults. In addition, it has been found that with
the present invention, the densities and/or basis weights of the
absorbent body 24 can be varied. In a particular aspect of the
invention, the absorbent body 24 has an absorbent capacity of at
least about 300 grams of synthetic urine.
[0080] In aspects wherein the absorbent body 24 includes the
combination of hydrophilic fibers and high-absorbency particles,
the hydrophilic fibers and high-absorbency particles can form an
average basis weight for the absorbent body 24 that is within the
range of about 400-900 grams per square meter. In certain aspects
of the invention, the average composite basis weight of such an
absorbent body 24 is within the range of about 500-800 grams per
square meter, and preferably is within the range of about 550-750
grams per square meter to provide the desired performance.
[0081] To provide the desired thinness dimension to the various
configurations of the absorbent article of the invention, the
absorbent body 24 can be configured with a bulk thickness that is
not more than about 0.6 centimeters. Preferably, the bulk thickness
is not more than about 0.53 centimeters, and more preferably is not
more than about 0.5 centimeters to provide improved benefits. The
bulk thickness is determined under a restraining pressure of 0.2
psi (1.38 kPa).
[0082] The high-absorbency material can be selected from natural,
synthetic, and modified natural polymers and materials. The
high-absorbency materials can be inorganic materials, such as
silica gels, or organic compounds, such as crosslinked polymers.
The term "crosslinked" refers to methods for effectively rendering
normally water-soluble materials substantially water insoluble but
swellable. Such methods include, for example, physical
entanglement, crystalline domains, covalent bonds, ionic complexes
and associations, hydrophilic associations such as hydrogen
bonding, and hydrophobic associations or Vander Waals forces.
[0083] Examples of synthetic, polymeric, high-absorbency materials
include the alkali metal and ammonium salts of poly(acrylic acid)
and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers),
maleic anhydride copolymers with vinyl ethers and alpha-olefins,
poly(vinyl pyrrolidone), poly(vinyl morpholinone), poly(vinyl
alcohol), and mixtures and copolymers thereof. Further polymers
suitable for use in the absorbent body 24 include natural and
modified natural polymers, such as hydrolyzed acrylonitrile-grafted
starch, acrylic acid grafted starch, methyl cellulose,
carboxymethyl cellulose, hydroxypropyl cellulose, and the natural
gums, such as alginates, xanthan gum, locust bean gum, and the
like. Mixtures of natural and wholly or partially synthetic
absorbent polymers can also be useful in the present invention.
[0084] The high absorbency material may be in any of a wide variety
of geometric forms. As a general rule, it is preferred that the
high absorbency material be in the form of discrete particles.
However, the high absorbency material may also be in the form of
fibers, flakes, rods, spheres, needles, or the like. In general,
the high absorbency material is present in the absorbent body 24 in
an amount of from about 5 to about 90 percent by weight, desirably
in an amount of at least about 30 percent by weight, and even more
desirably in an amount of at least about 50 percent by weight based
on a total weight of the absorbent body 24. For example, in a
particular aspect, the absorbent body 24 may include a laminate
which includes at least about 50 percent by weight and desirably at
least about 70 percent by weight of high-absorbency material
overwrapped by a fibrous web or other suitable material for
maintaining the high-absorbency material in a localized area.
[0085] An example of high-absorbency material suitable for use in
the present invention is SANWET IM 3900 polymer available from
Hoechst Celanese, a business having offices in Portsmouth,
Virginia. Other suitable superabsorbents may include FAVOR SXM 880
polymer obtained from Stockhausen, a business having offices in
Greensboro, N.C.
[0086] Optionally, a substantially hydrophilic tissue wrapsheet
(not illustrated) may be employed to help maintain the integrity of
the structure of the absorbent body 24. The tissue wrapsheet is
typically placed about the absorbent body 24 over at least the two
major facing surfaces thereof. The tissue wrapsheet can be composed
of an absorbent cellulosic material, such as creped wadding or a
high wet-strength tissue. In one aspect of the invention, the
tissue wrapsheet can be configured to provide a wicking layer that
helps to rapidly distribute liquid over the mass of absorbent
fibers constituting the absorbent body 24.
[0087] The absorbent body 24 of the different aspects of the
present invention further includes a plurality of zones of high air
permeability which allow air and vapors to readily pass through the
absorbent body 24 and through the vapor permeable outer cover 20
out of the diaper 10 into ambient air. For example, the absorbent
body 24 may include a plurality of air passageways that provide the
absorbent body 24 with zones or regions of high air permeability.
The portions of the absorbent body 24 adjacent the air passageways
provide zones or regions of high absorption. The zones of high air
permeability are designed to provide the maximum air exchange from
the absorbent body 24 while the zones of high absorption are
designed to receive and hold the majority of the body exudates. The
absorbent body 24 may define any number of zones of high air
permeability that provide the improved air exchange. Desirably, the
absorbent body 24 defines at least 3 and more desirably at least 5
different zones of high air permeability for improved
performance.
[0088] The zones of high air permeability, such as the air
passageways, are configured to enhance the breathability of the
article to reduce the hydration of the wearer's skin during use
without allowing excessive condensation of vapor, such as urine, on
the garment facing surface of the outer cover 20. Such condensation
of vapor on the outer surface of the diaper 10 can undesirably
dampen the wearer's clothes. The zones of high air permeability are
generally located in the area of the diaper over which air and
vapor can transfer from the bodyside liner 22, through the
absorbent body 24 and any other intervening layer or layers of
material, and out the vapor permeable outer cover 20. For example,
the zones of high air permeability may be located throughout the
entire absorbent body 24 or may be selectively located in those
regions of the absorbent body 24 that provide the maximum air
exchange, such as the intermediate section 16 of the diaper 20. In
a particular aspect, the zones of high air permeability are located
in the front and intermediate sections 12 and 16, respectively, of
the diaper 10 for improved air exchange.
[0089] The zones of high absorption, on the other hand, are not
designed to transfer a high level of air and vapor from the
interior of the diaper 10. Thus, the air exchange from the bodyside
liner 22 of the diaper 10 to the outer cover 20 of the diaper and
into the ambient atmosphere (exterior of the diaper 10) occurs
generally through the absorbent body 24 in the zones of high air
permeability. Some air exchange through the absorbent body 24 can
also occur in the zones of high absorption to a limited degree. The
zones of high air permeability may have any desired configuration
including rectangular, circular, hourglass, oval, and the like, and
may also include selected longitudinal or lateral strips or
multiple regions which may be intermittently located.
[0090] The zones of high air permeability may have any desired
dimensions that effectively provide improved air exchange while
preventing excessive condensation of vapor from the absorbent body
24 through and onto the garment facing surface of the outer cover
20. Desirably, the zones of high air permeability may define a
total area of from about 5 to about 75 percent, more desirably at
least about 10 percent, even more desirably from about 10 to about
70 percent, and still more desirably from about 10 to about 60
percent of the total surface area of the absorbent body 24 of the
diaper 10. For example, in a diaper 10 intended for use on a medium
sized infant, the zones of high air permeability may define a total
area of from about 6 to about 90 square centimeters.
[0091] When the total area of the zones of high air permeability is
greater than the above amounts, the diaper 10 may exhibit an
undesirable amount of condensation of vapor on the exposed, garment
facing surface of the outer cover 20 undesirably resulting in a
clammy feeling on the outer surface of the diaper 10. Whereas, when
the total area of the zones of high air permeability is less than
the above amounts, the diaper 10 may exhibit a low level of air
exchange resulting in high levels of skin hydration that can
undesirably lead to skin irritation and rash.
[0092] The zones of high air permeability of the absorbent body 24
of the diaper 10 are constructed to be substantially permeable to
at least air and preferably permeable to water vapor. For example,
the zones of high air permeability of the absorbent body 24 define
a Frazier Porosity value which is at least about 10 percent, more
desirably at least about 20 percent and even more desirably at
least about 50 percent greater than the Frazier Porosity value of
the zones of high absorption of the absorbent body 24. As used
herein, the term "Frazier Porosity" refers to the value determined
according to the Frazier Porosity Test set forth below. When the
zones of high air permeability exhibit Frazier Porosity values less
than those indicated above, the diaper 10 may exhibit a low level
of air exchange resulting in high levels of skin hydration that can
undesirably lead to skin irritation and rash.
[0093] The zones of high air permeability may be provided in a
variety of ways. The zones of high air permeability may be integral
portions of the absorbent body 24 of the absorbent article or may
be provided by apertures, holes or open spaces in the absorbent
body 24. For example, portions of the absorbent body 24 may be
discontinuous or removed to provide the zones. Alternatively, the
zones of high air permeability may be provided by portions of the
absorbent body 24 that are constructed to absorb less fluid
exudates thereby resulting in improved air flow through such
portions in use. For example, portions of the absorbent body 24 may
be void of or contain substantially less high-absorbency material
than other portions of the absorbent body 24 to provide such
improved air flow. Portions of the absorbent body 24 may otherwise
be treated or coated with a solution that renders them hydrophobic
to provide the zones of high air permeability in selected areas. In
other alternative configurations, the zones of high air
permeability may be provided by creating voids or holes in the
absorbent body 24 and placing other materials having a higher air
permeability than the absorbent body 24, such as those materials
described below as being suitable for the surge management layer
34, in the holes or voids.
[0094] Due to the thinness of absorbent body 24 and the high
absorbency material within the absorbent body 24, the liquid uptake
rates of the absorbent body 24, by itself, may be too low, or may
not be adequately sustained over multiple insults of liquid into
the absorbent body 24. To improve the overall liquid uptake and air
exchange, the diaper 10 of the different aspects of the present
invention may further include a porous, liquid-permeable layer of
surge management material 34, as representatively illustrated in
FIG. 1. The surge management layer 34 is typically less hydrophilic
than the absorbent body 24, and has an operable level of density
and basis weight to quickly collect and temporarily hold liquid
surges, to transport the liquid from its initial entrance point and
to substantially completely release the liquid to other parts of
the absorbent body 24. This configuration can help prevent the
liquid from pooling and collecting on the portion of the diaper 10
positioned against the wearer's skin, thereby reducing the feeling
of wetness by the wearer. The structure of the surge management
layer 34 also generally enhances the air exchange within the diaper
10.
[0095] Various woven and nonwoven fabrics can be used to construct
the surge management layer 34. For example, the surge management
layer 34 may be a layer composed of a meltblown or spunbond web of
synthetic fibers, such as polyolefin fibers. The surge management
layer 34 may also be a bonded-carded-web or an airlaid web composed
of natural and synthetic fibers. The bonded-carded-web may, for
example, be a thermally bonded web that is bonded using low melt
binder fibers, powder or adhesive. The webs can optionally include
a mixture of different fibers. The surge management layer 34 may be
composed of a substantially hydrophobic material, and the
hydrophobic material may optionally be treated with a surfactant or
otherwise processed to impart a desired level of wettability and
hydrophilicity. In a particular aspect, the surge management layer
34 includes a hydrophobic, nonwoven material having a basis weight
of from about 30 to about 120 grams per square meter.
[0096] For example, in a particular aspect, the surge management
layer 34 may include a bonded-carded-web, nonwoven fabric that
includes bicomponent fibers and that defines an overall basis
weight of about 83 grams per square meter. The surge management
layer 34 in such a configuration can be a homogeneous blend
composed of about 60 weight percent polyethylene/polyester
(PEIPET), sheath-core bicomponent fibers that have a fiber denier
of about 3 d and about 40 weight percent single component polyester
fibers that have a fiber denier of about 6 d and that have fiber
lengths of from about 3.8 to about 5.08 centimeters.
[0097] In the illustrated aspects, the surge management layer 34 is
arranged in a direct, contacting liquid communication with the
absorbent body 24. The surge management layer 34 may be operably
connected to the bodyside liner 22 with a conventional pattern of
adhesive, such as a swirl adhesive pattern. In addition, the surge
management layer 34 may be operably connected to the absorbent body
24 with a conventional pattern of adhesive. The amount of adhesive
add-on should be sufficient to provide the desired levels of
bonding, but should be low enough to avoid excessively restricting
the movement of liquid from the bodyside liner 22, through the
surge management layer 34 and into the absorbent body 24.
[0098] The absorbent body 24 is positioned in liquid communication
with surge management layer 34 to receive liquids released from the
surge management layer 34, and to hold and store the liquid. In the
shown aspect, the surge management layer 34 includes a separate
layer that is positioned over another, separate layer including the
absorbent body 24, thereby forming a dual-layer arrangement. The
surge management layer 34 serves to quickly collect and temporarily
hold discharged liquids, to transport such liquids from the point
of initial contact and spread the liquid to other parts of the
surge management layer 34, and then to substantially completely
release such liquids into the layer or layers constituting the
absorbent body 24.
[0099] The surge management layer 34 can be of any desired shape.
Suitable shapes include for example, circular, rectangular,
triangular, trapezoidal, oblong, dog-boned, hourglass-shaped, or
oval. In certain aspects, for example, the surge management layer
34 can be generally rectangular-shaped. In the illustrated aspects,
the surge management layer 34 is coextensive with the absorbent
body 24. Alternatively, the surge management layer 34 may extend
over only a part of the absorbent body 24. Where the surge
management layer 34 extends only partially along the length of the
absorbent body 24, the surge management layer 34 may be selectively
positioned anywhere along the absorbent body 24. For example, the
surge management layer 34 may function more efficiently when it is
offset toward the front waist section 12 of the diaper 10. The
surge management layer 34 may also be approximately centered about
the longitudinal center line of the absorbent body 24.
[0100] Additional materials suitable for the surge management layer
34 are set forth in U.S. Pat. No. 5,486,166 issued Jan. 23, 1996 in
the name of C. Ellis et al. and entitled "FIBROUS NONWOVEN WEB
SURGE LAYER FOR PERSONAL CARE ABSORBENT ARTICLES AND THE LIKE";
U.S. Pat. No. 5,490,846 issued Feb. 13, 1996 in the name of Ellis
et al. and entitled "IMPROVED SURGE MANAGEMENT FIBROUS NONWOVEN WEB
FOR PERSONAL CARE ABSORBENT ARTICLES AND THE LIKE"; and U.S. Pat.
No. 5,364,382 issued Nov. 15, 1994 in the name of Latimer et al.
and entitled "ABSORBENT STRUCTURE HAVING IMPROVED FLUID SURGE
MANAGEMENT AND PRODUCT INCORPORATING SAME", the disclosures of
which are hereby incorporated by reference.
[0101] As representatively illustrated in FIG. 1, the diaper 10 may
also include a ventilation layer 32 located between the outer cover
20 and the absorbent body 24. The ventilation layer 32 serves to
facilitate the movement of air within and through the diaper 10 and
prevent the outer cover 20 from being in surface to surface contact
with at least a portion of the absorbent body 24. Specifically, the
ventilation layer 32 serves as a conduit through which air and
water vapor can move from the absorbent body 24 through the vapor
permeable outer cover 20.
[0102] The ventilation layer 32 may be formed from materials
described above as being suitable for the surge management layer 34
such as nonwoven, (e.g., spunbond, meltblown or carded), woven, or
knitted fibrous webs composed of natural fibers and/or synthetic
polymeric fibers. Suitable fibers include, for example, acrylic
fibers, polyolefin fibers, polyester fibers, or blends thereof. The
ventilation layer 32 may also be formed from a porous foam material
such as an open-celled polyolefin foam, a reticulated polyurethane
foam, and the like. The ventilation layer 32 may include a single
layer of material or a composite of two or more layers of material.
In a particular aspect, the ventilation layer 32 includes a
hydrophobic, nonwoven material having a thickness of at least about
0.10 centimeters determined under a restraining pressure of 0.05
psi (0.34 kPa) and a basis weight of from about 20 to about 120
grams per square meter. For example, the ventilation layer 32 may
comprise a bonded-carded-web, nonwoven fabric that includes
bicomponent fibers and that defines an overall basis weight of
about 83 grams per square meter. The ventilation layer 32 in such a
configuration can be a homogeneous blend composed of about 60
weight percent polyethylene/polyester (PE/PET), sheath-core
bicomponent fibers that have a fiber denier of about 3 d and about
40 weight percent single component polyester fibers that have a
fiber denier of about 6 d and that have fiber lengths of from about
3.8 to about 5.08 centimeters.
[0103] The ventilation layer 32 can be of any desired shape.
Suitable shapes include for example, circular, rectangular,
triangular, trapezoidal, oblong, dog-boned, hourglass-shaped, or
oval. The ventilation layer 32 may extend beyond, completely over
or partially over the absorbent body 24. For example, the
ventilation layer 32 may suitably be located over the intermediate
section 16 of the diaper 10 and be substantially centered
side-to-side with respect to the longitudinal centerline 36 of the
diaper 10. It is generally desired that the entire absorbent body
24 be overlaid with the ventilation layer 32 to prevent
substantially all surface to surface contact between the outer
cover 20 and the absorbent body 24. In the illustrated aspects, the
ventilation layer 32 is coextensive with the absorbent body 24.
This allows for the maximum degree of air exchange with minimal
dampness on the garment facing surface of the outer cover 20.
[0104] In the illustrated aspects, the ventilation layer 32 is
arranged in a direct, contacting liquid communication with the
absorbent body 24. The ventilation layer 32 may be operably
connected to the outer cover 20 with a conventional pattern of
adhesive, such as a swirl adhesive pattern. In addition, the
ventilation layer 32 may be operably connected to the absorbent
body 24 with a conventional pattern of adhesive. The amount of
adhesive add-on should be sufficient to provide the desired levels
of bonding, but should be low enough to avoid excessively
restricting the movement of air and vapor from the absorbent body
24 and through the outer cover 20.
[0105] The ventilation layer 32 may further serve to quickly
collect and temporarily hold discharged liquids, which pass through
the absorbent body 24 and, in particular, through the zones of high
air permeability within the absorbent body 24. The ventilation
layer 32 may then transport such liquids from the point of initial
contact and spread the liquid to other parts of the ventilation
layer 32, and then substantially completely release such liquids
into the layer or layers of the absorbent body 24.
[0106] In order to protect the barrier of the skin covered by the
diaper 10, a composition is applied to the bodyfacing surface 11 of
the bodyside liner 22 of the diaper 10. The composition generally
can include emollient(s), viscosity enhancer(s) and decoupling
polymer(s). The composition can also include natural fats or oils,
solidifying agents and sterols or sterol derivatives. Additionally,
the composition can include rheology modifiers and clays. For
example, the compositions of the invention may include from about
40 to about 95 percent by weight of one or more emollients; from
about 0.1 to about 40 percent by weight of one or more viscosity
enhancers; and, from about 0.1 to about 20 percent by weight of one
or more decoupling polymers. The composition may include other
ingredients as well. Ranges are used to describe the relative
amounts of components in the compositions of the invention as well
as to describe the relative physical properties of the
compositions. These ranges are illustrative and one of skill in the
art will recognize that the nature of the composition will dictate
the various levels of components that must be used to achieve the
intended benefit for the skin barrier. The levels can be determined
by routine experimentation in view of the disclosure provided
herein.
[0107] The compositions of the invention can be in a variety of
physical forms including emulsions, lotions, creams, ointments,
salves, suspensions, gels or hybrids of these forms.
[0108] The emollients of the compositions act as lubricants to
reduce the abrasiveness of the bodyside liner 22 to the skin and,
upon transfer to the skin, help to maintain the soft, smooth and
pliable appearance of the skin. Emollients are skin conditioning
ingredients that help to soften, smooth, plasticize, lubricate,
moisturize, improve the appearance of, improve the feel of and
protect the skin. Suitable emollients that can be incorporated into
the compositions include oils such as petroleum based oils,
petrolatum, vegetable based oils, hydrogenated vegetable oils,
animal oils, hydrogenated animal oils, mineral oils, natural or
synthetic oils, alkyl dimethicones, alkyl methicones,
alkyldimethicone copolyols, phenyl silicones, alkyl
trimethylsilanes, dimethicone, lanolin and its derivatives, esters,
branched esters, glycerol esters and derivatives, propylene glycol
esters and derivatives, alkoxylated carboxylic acids, alkoxylated
alcohols, fatty alcohols, triglycerides, alkyl hydroxystearates and
mixtures of such compounds. The esters can be selected from, but
are not limited to, cetyl palmitate, stearyl palmitate, cetyl
stearate, isopropyl laurate, isopropyl myristate, isopropyl
palmitate and mixtures thereof. Ethers such as eucalyptol, cetearyl
glucoside, dimethyl isosorbicide polyglyceryl-3 cetyl ether,
polyglyceryl-3 decyltetradecanol, propylene glycol myristyl ether
and mixtures thereof can also be used as emollients. The fatty
alcohols include octyidodecanol, lauryl, myristyl, cetyl, stearyl
and behenyl alcohol and mixtures thereof. For example, a
particularly well suited emollient is petrolatum. Other
conventional emollients may also be added in a manner that
maintains the desired properties of the compositions set forth
herein.
[0109] To provide improved stability and transfer to the skin of
the wearer, the compositions may include from about 1 to about 95
percent by weight, desirably from about 20 to about 75 percent by
weight, and more desirably from about 40 to about 60 percent by
weight of the emollient. In particular aspects, the emollient can
be at least a minimum of about 1 percent by weight. The emollient
can alternatively be at least about 20 percent, and optionally, can
be at least about 40 percent to provide improved performance. In
other aspects, the emollient can be not more than a maximum of
about 95 percent by weight. The emollient can alternatively be not
more than about 75 percent, and optionally, can be not more than
about 60 percent to provide improved effectiveness. Compositions
that include an amount of emollient greater than the recited
amounts tend to have lower viscosities that undesirably lead to
migration of the composition. Whereas, compositions that include an
amount of emollient less than the recited amounts tend to provide
less transfer to the wearer's skin.
[0110] The solidifying agent(s) in the compositions of the present
invention primarily functions to solidify the composition so that
the composition is a solid at room temperature and has a
penetration hardness of at least 5 mm and has a melting point of at
least 32.degree. C. The solidifying agent may also provide a
tackiness to the composition that improves the transfer by adhesion
to the skin of the wearer. Depending on the solidifying agent
selected, the solidifying agent can also modify the mode of
transfer so that the composition tends to fracture or flake off
instead of actually rubbing off onto the skin of the wearer which
can lead to improved transfer to the skin. The solidifying agent
may further function as an emollient, occlusive agent, moisturizer,
barrier enhancer, viscosity enhancer and combinations thereof. The
solidifying agents may include waxes as well as compounds that
perform functionally as waxes.
[0111] The solidifying agents can be selected from alkyl siloxanes,
polymers, hydrogenated vegetable oils having a melting point of
35.degree. C. or greater, fatty acid esters with a melting point of
35.degree. C. or greater, alkyl hydroxystearates (>C.sub.16),
branched esters, alkoxylated alcohols and alkoxylated carboxylic
acid. Additionally, the solidifying agents can be selected from
animal, vegetable and mineral waxes and alkyl silicones. Examples
of solidifying agents include, but are not limited to, the
following: alkyl silicones, alkyl trimethylsilanes, beeswax,
behenyl behenate, behenyl benzoate, C.sub.24-C.sub.28 alkyl
dimethicone, C.sub.30 alkyl dimethicone, cetyl methicone, stearyl
methicone, cetyl dimethicone, stearyl dimethicone, cerotyl
dimethicone, candelilla wax, carnauba, synthetic carnauba, PEG-12
carnauba, cerasin, hydrogenated microcrystalline wax, jojoba wax,
microcrystalline wax, lanolin wax, ozokerite, paraffin, synthetic
paraffin, cetyl esters, behenyl behenate, C.sub.20-C.sub.40 alkyl
behenate, C.sub.12-C.sub.15 lactate, cetyl palmitate, stearyl
palmitate, isosteryl behenate, lauryl behenate, stearyl benzoate,
behenyl isostearate, cetyl myristate, cetyl octanoate, cetyl
oleate, cetyl ricinoleate, cetyl stearate, decyl oleate,
di-C.sub.12-C.sub.15 alkyl fumerate, dibehenyl fumerate, myristyl
lactate, myristyl lignocerate, myristyl myristate, myristyl
stearate, lauryl stearate, octyidodecyl stearate, octyidodecyl
stearoyl stearate, oleyl arachidate, oleyl stearate, tridecyl
behenate, tridecyl stearate, tridecyl stearoyl stearate,
pentaerythrityl tetrabehenate, pentaerythritylhydrogenated
rosinate, pentaerythrityl distearate, pentaerythrityl tetraabeite,
pentaerythrityl tetracocoate, pentaerythrityl tetraperlargonate,
pentaerythrityl tetrastearate, ethylene vinyl acetate,
polyethylene, hydrogenated cottonseed oil, hydrogenated vegetable
oil, hydrogenated squalene, hydrogenated coconut oil, hydrogenated
jojoba oil, hydrogenated palm oil, hydrogenated palm kernel oil,
hydrogenated olive oil, polyamides, metal stearates and other metal
soaps, C.sub.30-C.sub.60 fatty alcohols, C.sub.20+ fatty amides,
polypropylene, polystyrene, polybutane, polybutylene terephthalate,
polydipentane, polypropylene, zinc stearate, dodecyl laurate,
stearyl palmitate, octadecyl hexadecanoate, octadecyl palmitate,
stearyl behenate, docosyl octanoate, tetradecyl-octadecanyl
behenate, hexadecyl-cosanyl hexacosanate, shellac wax, glycol
montanate, fluoranated waxes, C.sub.20-C.sub.40 alkyl
hydroxystearyl stearate and mixtures of such compounds and mixtures
of such compounds. In one aspect, the solidifying agent is a blend
including about 70 weight percent cerasin wax, about 10 weight
percent microcrystalline wax, about 10 weight percent paraffin wax
and about 10 weight percent cetyl esters (synthetic spermaceti
wax). Appropriate solidifying agents also include
alkylmethylsiloxanes that can be described as non-volatile,
occlusive silicone-aliphatic hydrocarbon hybrid waxes. An example
of an alkylmethylsiloxane wax is a
poly(n-alkylmethylsiloxane)dimethylsiloxane. The
poly(n-alkylmethylsiloxa- ne)dimethylsiloxane can have an n-alkyl
substitution of an average of 16 carbon atoms or above with an
average of more than 2 alkyl groups per molecule, with hydrocarbon
contents of at least 40% and with an average molecular weight of at
least 1800 or higher. Examples of desirable alkylmethylsiloxanes
for use in the compositions of the invention include random
copolymers having the following formula:
(CH.sub.3).sub.3SiO((CH.sub.3).sub.2SiO).sub.x(((CH.sub.3)C.sub.3H.sub.6R)-
SiO).sub.ySi(CH.sub.3).sub.3
[0112] The "R" component of the formula can be an aliphatic
hydrocarbon substituent where the chain length is from C.sub.4 to
C.sub.45. In particular, "R" can be C.sub.16, C.sub.16-18,
C.sub.20-24 or C.sub.30-45. For example, C.sub.30-45
alkylmethylsiloxane is commercially available as trade designation
"SF1642" from General Electric Silicones or "AMS-C.sub.30" from Dow
Corning Silicones. The value of "x" is on average more than 2 and
the value of "y" is at least 1. The nature of the
alkylmethylsiloxane must be balanced between its compatibility with
dimethicone or polydimethyl siloxane and its compatibility with
organic compounds like petrolatum and waxes. For example, as "x"
increases, "y" decreases and "R" is small, the molecule increases
its compatibility with dimethicone but increases its compatibility
with organic compounds. Alternatively, as "x" decreases, "y"
increases and "R" is C.sub.18+, the molecule decreases its
compatibility with dimethicone but increases its compatibility with
organic compounds. These solidifying agents can be used to
stabilize dimethicone-containing compositions of the invention.
[0113] To provide improved transfer to the skin of the wearer, the
composition may include from about 5 to about 95 percent by weight,
desirably from about 25 to about 75 percent by weight, and more
desirably from about 30 to about 50 percent by weight of
solidifying agent(s). ). In particular aspects, the solidifying
agent can be at least a minimum of about 5 percent by weight. The
solidifying agent can alternatively be at least about 25 percent,
and optionally, can be at least about 30 percent to provide
improved performance. In other aspects, the solidifying agent can
be not more than a maximum of about 95 percent by weight. The
solidifying agent can alternatively be not more than about 75
percent, and optionally, can be not more than about 50 percent to
provide improved effectiveness. Compositions that include an amount
of solidifying agent less than the recited amounts tend to be too
soft and may have lower viscosities that may undesirably lead to
migration of the composition away from bodyfacing surfaces 11 of
the absorbent article, thus diminishing transfer to the wearer's
skin. Whereas, compositions that include an amount of solidifying
agent greater than the recited amounts tend to provide less
transfer to the wearer's skin.
[0114] One or more viscosity enhancers may be added to the
composition to increase the viscosity, to help stabilize the
formulation on the bodyfacing surface 11 of the bodyside liner 22
and, thereby, to reduce migration and improve transfer to the skin.
The viscosity enhancer increases the meltpoint viscosity of the
compositions to have a high viscosity (greater than about 50,000
centipoise) under low shear at the "hot box car" stability
temperature of about 54.5.degree. C. and at lower temperatures.
Having viscosity at elevated temperatures prevents the compositions
from migrating into or away from the materials to which they are
applied. However, the viscosity enhancer component also provides a
low viscosity (less than about 5,000 centipoise) under shear for
the compositions at process conditions. Typically, process
temperatures are approximately 5.degree. C. above the melting point
of the composition. Generally, the process temperature is about
60.degree. C. or higher. Different compositions of the invention
will have different melting points. The viscosity enhancers of the
invention are capable of maintaining the viscosity of compositions
of the invention up to temperatures just below the desired
processing temperature for a given composition Examples of suitable
viscosity enhancers include polyolefin resins, lipophilic/oil
thickeners, ethylene/vinyl acetate copolymers, organically modified
clays, polyethylene, silica, silica silylate, silica methyl
silylate, colloidal silicone dioxide, cetyl hydroxy ethyl
cellulose, other organically modified celluloses, PVP/decane
copolymer, PVM/MA decadiene crosspolymer, PVP/eicosene copolymer,
PVP/hexadecane copolymer, microcrystalline wax,
hexadecyl-cosanyl-hexacosanate, shellac wax, glycol montanate,
PEG-12 carnauba, synthetic paraffin, ozokerite, C.sub.20-C.sub.40
alkyl hydroxystearyl stearate, polyperfluoromethylisopr- opylether
montan wax and mixtures of these compounds. A particularly well
suited viscosity enhancer is an ethylene/vinyl acetate copolymer
commercially available from E. I. Dupont De Ne Mours under the
trade designation "ELVAX". Additionally, the compounds identified
herein as suitable solidifying agents may also function as
viscosity enhancers to benefit the rheology of the compositions of
the invention.
[0115] To provide the improved transfer to the skin of the wearer,
the composition may include from about 0.1 to about 40 percent by
weight, desirably from about 3 to about 20 percent by weight, and
more desirably from about 5 to about 10 percent by weight of the
viscosity enhancer for reduced migration and improved transfer to
the wearer's skin. ). In particular aspects, the viscosity enhancer
can be at least a minimum of about 0.1 percent by weight. The
viscosity enhancer can alternatively be at least about 3 percent,
and optionally, can be at least about 5 percent to provide improved
performance. In other aspects, the viscosity enhancer can be not
more than a maximum of about 40 percent by weight. The viscosity
enhancer can alternatively be not more than about 20 percent, and
optionally, can be not more than about 10 percent to provide
improved effectiveness.
[0116] The compositions of the invention may also include from
about 0.1 to about 20 percent by weight of one or more anionic
polymers, such as anionic decoupling polymers. More specifically,
the compositions may include from about 0.5 to about 20 percent by
weight of one or more decoupling polymers. Even more specifically,
the compositions may include from about 1 to about 7 percent by
weight of decoupling polymers.). In particular aspects, the
decoupling polymers can be at least a minimum of about 0.1 percent
by weight. The decoupling polymers can alternatively be at least
about 0.5 percent, and optionally, can be at least about 1 percent
to provide improved performance. In other aspects, the decoupling
polymers can be not more than a maximum of about 20 percent by
weight. The decoupling polymers can alternatively be not more than
about 7 percent. The decoupling polymers, in combination with the
other components of the composition, provide several benefits to
the skin, particularly skin that is frequently covered by an
absorbent article and that is exposed to biological insults. As a
class, anionic polymers can contribute to providing the skin health
benefits of the compositions of the invention.
[0117] As a class, anionic polymers can contribute to providing the
skin health benefits of the compositions of the invention. Anionic
polymers are polymers that carry negative charges at their
functional groups which may include carboxylates, sulphonates and
other such functional groups. The number of negative charges
carried by an anionic polymer depends on the number of functional
groups that the polymer has. Generally speaking, the anionic
polymers that contribute to improving skin health in the
compositions of the invention are water-soluble polymers. However,
the compositions of the invention are not limited to including
water-soluble polymers. The anionic polymers may also have
hydrophobic groups, such as lauryl and stearyl groups. These
anionic polymers become hydrophobically modified polymers. Because
such polymers have both hydrophilic and hydrophobic groups in the
same molecule, the polymers behave like surfactants. These
"surfactant-like" polymers are surface active and like to situate
themselves at the interface between hydrophilic and hydrophobic
components. Sometimes, these "surfactant-like" polymers are also
referred to as "polysoaps".
[0118] Examples of decoupling polymers that have been found to
provide skin health benefits in the compositions of the invention
include those polymers having a hydrophilic backbone. The
hydrophilic backbone of the decoupling polymers can be composed of
one or two monomer types or can be composed of three or more
different monomer types. The decoupling polymers of the invention
can include one or more polymers having a hydrophilic backbone of
homopolymers of acrylic acid, acrylic acid/maleic acid copolymers,
poly(2-hydroxyethyl acrylate), polysaccharides, cellulose ethers,
polyglycerols, polyacrylamides, polyvinylalcohol/polyvi- nylether
copolymers, poly(sodium vinyl sulphonate), poly(2-sulphato ethyl
methacrylate), poly(acrylamidomethylpropane sulphonate) and
mixtures of such polymers.
[0119] While the decoupling polymers of the invention may have a
hydrophilic backbone, it is desirable for the decoupling polymers
to have one or more hydrophobic side chains. The hydrophobic side
chains can be part of a monomer unit that is incorporated into the
decoupling polymer by copolymerization with the hydrophilic
backbone. While a variety of hydrophobic side chains can be
copolymerized into the decoupling polymers, the hydrophobic side
chains can include those side chains that, when isolated from their
linkage, are relatively water insoluble. For example, the
hydrophobic side chains and monomers can have solubilities of less
than 1 g/l, less than 0.5 g/l or less than 0.1 g/l in water at
ambient temperature and at a pH of about 3 to about 12.5.
[0120] The hydrophobic side chains can include siloxanes and
saturated and unsaturated alkyl chains. The saturated and
unsaturated alkyl chains can have from 5 to 24 carbon atoms.
Desirably, the alkyl chains have from 6 to 18 carbon atoms and,
more desirably, the alkyl chains have from 8 to 16 carbon atoms.
The hydrophobic side chains can be bonded to a hydrophilic backbone
of the decoupling polymers by an alkoxylene or a polyalkoxylene
linkage, such as a polyethoxy, polypropoxy, butyloxy or mixed
linkage having from 1 to 50 alkoxylene groups. Additionally, the
hydrophobic side chains can be selected from relatively hydrophobic
alkoxy groups such as butylene oxide and propylene oxide. In such
cases, the hydrophobic side chains have the character of a nonionic
surfactant. Additional examples of suitable decoupling polymers are
described in U.S. Pat. No. 5,147,576 issued to Montague et al., the
disclosure of which is incorporated by reference herein.
[0121] Sometimes it is necessary for the compositions of the
invention to include additional components that can be used to
emulsify decoupling polymer(s) with the rest of the composition. If
the decoupling polymer is not properly incorporated into the
composition, it may not have the bioavailability to provide
benefits to the skin. In addition to modifications to the
formulation, decoupling polymers can also be better incorporated
through the use of processing techniques. For compositions of the
invention including some decoupling polymers, it may be necessary
to add an emulsifying agent such as an emulsifier having an HLB
less than 7. An appropriate emulsifying agent is ABIL EM90
emulsifier available from Goldschmidt AG of Germany. Other
appropriate emulsifiers include sorbitan monooleate, sorbitan
sesquioleate, sorbitan trioleate and glycerol monooleate. The
polymers can also be better incorporated into the composition by
using high shear in processing or a suitable viscosity enhancer.
Another option for dispersing a decoupling polymer such as NARLEX
DC-1 polymer is to first blend the polymer with a hydrophilic
solvent such as water, propylene glycol, glycerol or butylene
glycol. Dispersing the decoupling polymer in a hydrophilic solvent
and using an emulsifying agent to incorporate the solvent into the
remainder of the composition provides the decoupling polymer in a
"bioavailable" form in which it can contribute to protecting the
skin barrier and subduing the inflammatory response of the
skin.
[0122] For the reasons described above, emulsifiers or combinations
of emulsifiers, particularly those of HLB below 7, may be useful
for purposes of the present invention at ievels to from about 0.1
to about 10% by weight. Suitable emulsifiers include alkoxylated
C.sub.8-C.sub.30 fatty acids and fatty alcohols. Examples of such
emulsifiers are polyoxyethylene (2) lauryl ether, polyoxyethylene
(3) monostearate, polyoxyethylene (6) cetyl ether and
polyoxyethylene (5) stearyl ether and Myreth-3-Myristate (CTFA
name) available commercially as "Cetiol 1414-E.RTM.". Other
suitable emulsifiers included cetyl phosphate salts and alkyl
dimethicone copolyol, the latter commercially available as ABIL
EM90 emulsifier from Goldschmidt AG of Germany. Phosphatides such
as lecithin may also be useful as emulsifiers in the compositions
of the invention.
[0123] In another aspect, the compositions of the invention may
include from about 0.1 to about 95 percent by weight of natural
fats or oils, from about 0.1 to about 10 percent by weight of
sterols or sterol derivatives, from about 1 to about 95 percent by
weight of emollient, from about 0.1 to about 40 percent by weight
of viscosity enhancer and from about 0.1 to about 20 percent by
weight of decoupling polymer. In such aspects, the compositions of
the invention can include fats and oils that provide a source of
essential and non-essential fatty acids similar to those found in
the skin's natural barrier. Fats and oils include compounds that
are fats, oils, essential oils, fatty acids, fatty alcohols,
phospholipids and mixtures of such compounds. Fats and oils include
oils derived from plant and animal sources. Similarly, the
essential oils include essential oils derived from plant sources.
Those of skill in the art would understand that all compounds
commonly understood to have the structure of or to function as
fats, oils, essential oils, fatty acids, fatty alcohols and
phospholipids can be used as the natural fat or oil component of
the composition of the invention. While an exhaustive list of each
and every fat and oil that could be used in the compositions of the
invention is not provided, those of skill in the art will
understand and appreciate the individual compounds that can serve
as a fat or oil component of the compositions of the invention.
[0124] Representative examples of fats and oils include, but are
not limited to: Avocado Oil, Apricot Oil, Babassu Oil, Borage Oil,
Camellia Oil, Canola Oil, Castor Oil, Coconut Oil, Corn Oil,
Cottonseed Oil, Evening Primrose Oil, Hydrogenated Cottonseed Oil,
Hydrogenated Palm Kernel Oil, Maleated Soybean Oil, Meadowfoam Oil,
Palm Kernel Oil, Peanut Oil, Rapeseed Oil, Safflower Oil,
Sphingolipids, Sweet Almond Oil, Tall Oil, Lanolin, Lanolin
Alcohol, Lauric Acid, Palmitic Acid, Stearic Acid, Linoleic Acid,
Stearyl Alcohol, Lauryl Alcohol, Myristyl Alcohol, Behenyl Alcohol,
Rose Hip Oil, Calendula Oil, Chamomile Oil, Eucalyptus Oil, Juniper
Oil, Sandlewood Oil, Tea Tree Oil, Sunflower Oil, and Soybean Oil.
Another suitable fat/oil for the compositions of the invention is
PROLIPID 141 blend available from International Specialty Products
of Wayne, New Jersey. The PROLIPID 141 blend is a mixture of
glyceryl stearate, fatty acids, fatty alcohols and
phospholipids.
[0125] In order to assist in replenishing skin barrier enhancing
agents, the compositions of the invention may include fats and oils
in an amount of from about 0.1 to about 95 percent by weight,
desirably from about 5 to about 75 percent by weight, and more
desirably from about 10 to about 50 percent by weight of the
composition.). In particular aspects, the fats and oils can be at
least a minimum of about 0.1 percent by weight. The fats and oils
can alternatively be at least about 5 percent, and optionally, can
be at least about 10 percent to provide improved performance. In
other aspects, the fats and oils can be not more than a maximum of
about 95 percent by weight. The fats and oils can alternatively be
not more than about 75 percent, and optionally, can be not more
than about 50 percent to provide improved effectiveness.
[0126] The compositions of the invention also include sterols and
sterol derivatives that act in combination with the natural
fats/oils to provide natural skin barrier enhancement and skin
barrier recovery. Sterols and sterol derivatives that can be used
in the compositions of the invention include, but are not limited
to: .beta.-sterols having a tail on the 17 position and having no
polar groups for example, cholesterol, sitosterol, stigmasterol,
and ergosterol, as well as, C.sub.10-C.sub.30
cholesterol/lanosterol esters, cholecalciferol, cholesteryl
hydroxystearate, cholesteryl isostearate, cholesteryl stearate,
7-dehydrocholesterol, dihydrocholesterol, dihydrocholesteryl
octyldecanoate, dihydrolanosterol, dihydrolanosteryl
octyldecanoate, ergocalciferol, tall oil sterol, soy sterol
acetate, lanasterol, soy sterol, avocado sterols, "AVOCADIN" (trade
name of Croda Ltd of Parsippany, N.J.), sterol esters and similar
compounds, as well as mixtures thereof. The compositions of the
invention can include sterols, sterol derivatives or mixtures of
both sterols and sterol derivatives in an amount of from about 0.1
to about 10 percent by weight, desirably from about 0.5 to about 5
percent by weight and more desirably from about 0.8 to about 1
percent by weight of the composition.). In particular aspects, the
sterols can be at least a minimum of about 0.1 percent by weight.
The sterols can alternatively be at least about 0.5 percent, and
optionally, can be at least about 0.8 percent to provide improved
performance. In other aspects, the sterols can be not more than a
maximum of about 10 percent by weight. The sterols can
alternatively be not more than about 5 percent, and optionally, can
be not more than about 1 percent to provide improved
effectiveness.
[0127] The compositions of the invention may also include one or
more rheology modifiers. Rheology modifiers are compounds that
increase the viscosity of the compositions at lower temperatures as
well as process temperatures. Rheology modifiers or suspending
agents are also compounds that provide "structure" to the
compositions to prevent settling out (separation) of insoluble and
partially soluble components. By increasing the viscosity at
process temperatures, the rheology modifiers will increase the
viscosity above 200 centipoise. However, the rheology modifiers are
thixotropic in behavior and, therefore, their viscosity decreases
as shear and pressure increases. Consequently, when the rheology
modifiers are used in the compositions of the invention, they
maintain the suspension of insoluble and partially soluble
components. This capability can be particularly important if,
during processing, the composition must be left stagnant in process
lines and hoses. The rheology modifiers will maintain the
suspension of the insoluble and partially soluble components for a
period of time that depends on the viscosity of the composition and
on the amount of rheology modifier present. The thixotropic
behavior of the rheology modifiers causes their viscosity to drop
when processing is resumed and the composition is no longer
stagnant due to the application of pressure and shear forces. The
rheology modifiers provide different benefits than the viscosity
enhancers described herein. The viscosity enhancers increase the
melt-point viscosity of the compositions, but the viscosity
enhancers may not provide the correct rheology to suspend insoluble
particulates or materials.
[0128] In addition to stabilizing the suspension of insoluble and
partially soluble components, the rheology modifiers of the
invention also help to stabilize the compositions on the bodyfacing
or other materials to which the compositions are applied. Examples
of suitable rheology modifiers include silica, silica silylate,
silica methyl silylate, quaternary starch compounds, quaternary
clay compounds, organically modified clays and mixtures thereof.
The organically modified clays are typically used in combination
with an activator such as propylene carbonate, ethanol, propanol,
acetone, alpha hydroxy acids or mixtures of such activators. Such
rheology modifiers can help maintain the suspension of an insoluble
or partially soluble emollient, such as a siloxane, within the
composition. The compositions of the invention can include from
about 0.5 to about 20 percent by weight of one or more rheology
modifiers.
[0129] The use of one or more than one rheology modifier, such as
an organically modified clay in combination with a silica, can
provide a benefit to the rheology of the compositions by increasing
the viscosity of the compositions at process temperatures. When a
silica, an organically modified clay or both are used in an
ointment or lotion type composition, it is expected that they will
increase the hardness of the composition and, consequently, have a
potentially negative effect on transfer of the ointment to the
skin. However, when a natural clay or a synthetic analog of a
natural clay is used in combination with an organically modified
clay or a silica, there is an unexpected, synergistic enhancement
of the rheology of the composition. The organically modified clay
and silica assist the suspension of the natural clay (or synthetic
analog of the natural clay) in the compositions of the invention.
When a natural clay is combined with an organically modified clay
or a silica, a small amount of shear (such as rubbing) will
unexpectedly cause the composition to become soft and to spread
easily. Therefore, when such a combination is used in the
compositions of the invention, there is an improvement in the
transfer of the composition from the bodyside liner of the article
to the skin. Though these compositions provide improved transfer
from the liner to the skin, they remain stable on the bodyside
liner under storage conditions. Natural clays include
montmorillonite, bentonite, beidellite, hectorite, saponite,
stevensite, magnesium aluminum silicate and similar clays.
Synthetic analogs of natural clays, such as LAPONITE synthetic clay
available from Southern Clay Products Inc. of Gonzales, Tex. can
also be used to provide the rheology benefit to compositions of the
invention when used in combination with organically modified clays
or silica. Natural clays and synthetic analogs of natural clays can
be included in the compositions of the invention in amounts of from
about 0.5 to about 20 percent by weight of the composition.
[0130] The unexpected benefits provided by the combination of
natural clay with organically modified clay or silica in the
compositions of the invention are demonstrated by tests measuring
the relationship between the amount of composition transferred and
the penetration hardness of the composition. Prior to identifying
the benefits provided by combining natural clay with organically
modified clays or silicas, it was believed that as the penetration
hardness of a composition was increased, the less that composition
could be transferred. The penetration hardness of a composition is
typically measured using the standardized method of ASTM D1321. A
method has been developed for measuring the amount of composition
transferred from a surface. Composition transfer is measured using
an Ink Rub Tester such as Model #10-18-01 manufactured by Testing
Machines Inc. For purposes of the method described herein, the Ink
Rub Tester is set to have the following settings: (1) Cycles=50;
(2) Cycles/minute=100; (3) Alarm=on; (4) Pause every=off; and (5)
Count=down. A four pound weighted block is used in order to more
closely simulate the pressure applied by an infant to an absorbent
article, such as a diaper, while sitting or moving. The receptor or
receiving material is held to the four pound weighted block by four
magnets. The four magnets are positioned so that there are two
evenly spaced on either side of the four pound weighted block.
Typically, the receptor material is Natural Silk Noil, style #651,
which is available from Testfabrics, Inc. The receptor material is
cut to have dimensions of 2 inches by 6 inches. Desirably, the
magnets are high powered neodymium magnets having a diameter of
0.25 inches and a height of 0.25 inches. Preferably, the tension on
the receptor material is uniform and the receptor material is held
tightly with no gaps between the weighted block and the receptor
material. The receptor material should not, however, be subjected
to extraordinary strain.
[0131] The base or liner material that is treated with a
composition is centered on a rubber pad that will be brought into
contact with the four pound weighted block during the test. The
liner material is typically a spunbond liner material with UVITEX
fluorescener laced add-on. The planar dimension of the rubber pad
is approximately 2.5 inches by 6 inches. The liner material is
usually cut to dimensions of approximately 3 inches by 9 inches in
order to completely cover the rubber pad. A composition is applied
to the liner material using a slot-coating technique. Desirably,
the slot-coated lines of composition are aligned lengthwise with
the length of the rubber pad and the lines are centered as much as
possible. Both ends of the rubber pad have strips of hook 88 VELCRO
tape adhered to them. The liner material is held in place on the
rubber pad by pressing the liner material against the VELCRO tapes.
The liner material should be as wrinkle-free as possible when
positioned against the rubber pad. Two three inch wide IDL ball
bearing clips are then attached to either end of the rubber pad in
order to hold the liner material in place and to prevent movement
of the liner material.
[0132] Prior to attachment to the four pound weighted block, the
receptor material should be weighed on a balance that is
significant to at least decimal places. Prior to placement on the
weighing plate of the balance, the receptor material should be
tri-folded so that no portion is hanging off of the weighing plate.
Care should be taken to make sure there are no threads hanging from
the receptor material as well. The initial mass of the receptor
material is recorded. Gloves should be worn during handling of each
of the materials in order to prevent transfer of oils naturally
present on hands to the test materials. Once both the receptor
material and liner material are secured, the test is conducted
using the Ink Rub Tester settings described previously. At the end
of the test, the liner material is removed and thrown away. The
receptor material is removed and sprayed with Milty Zerostat 3
Anti-Static Pistol available from SPI Supplies. After removal of
static, the receptor material is once again tri-folded and its mass
is recorded using the balance. The change in mass is the difference
between the initial and final masses of the receptor material and
is representative of the amount of composition transferred from the
liner material.
[0133] A series of Ink Rub Tester tests were conducted on "control"
compositions including only petrolatum and a wax and test
compositions representative of compositions of the invention
containing natural clay in combination with organically modified
clay or silica. The penetration hardnesses of the compositions were
also measured using the standardized test method identified
previously. Descriptions of the compositions, the penetration
hardnesses and the amounts transferred (as measured by the Ink Rub
Tester test method) are provided in Table 1. below. Each of the
liner materials used in the Ink Rub Tester tests had 0.40 grams of
composition applied by slot coating.
1TABLE 1 Average Penetration Average Amount Test Composition
Hardness (millimeters) Transferred (grams) 80% Petrolatum 23.1
0.0223 20% Ozokerite Wax 60% Petrolatum 8.9 0.0106 40% Ozokerite
Wax 40% Petrolatum 6.6 0.0042 60% Ozokerite Wax 20% Petrolatum 1.6
0.0012 80% Ozokerite Wax Composition A 5.2 0.0124 Composition B 7.4
0.0166
[0134] The average penetration hardness measurements are based on a
sample size of ten. The average amount transferred measurements are
based on a sample size of ten. Composition A includes 39.7%
petrolatum; 36% ozokerite wax; 1% alkyl silicone wax; 10% sunflower
oil; 0.8% soy sterol; 1% PROLIPID 141 blend; 2% dimethicone; 7.5%
LAPONITE synthetic analog bentonite clay; and 2% fumed silica.
Composition B includes 37.2% petrolatum; 36% ozokerite wax; 1%
alkyl silicone wax; 10% sunflower oil; 0.8% soy sterol; 1% PROLIPID
141 blend; 2% dimethicone; 10% LAPONITE synthetic analog bentonite
clay; and 2% fumed silica. The values for average amount
transferred are plotted against the values for average penetration
hardness in FIG. 4. The "H1310 Needle" refers to a specific part
for the penetrometer instrument used to measure hardness. With the
non-natural clay compositions, there is a linear relationship
between amount transferred and penetration hardness. With the
natural clay containing compositions, there is also a linear
relationship between the amount transferred and penetration
hardness, however, the slope of the line is significantly greater.
Therefore, unexpectedly, for two compositions of the same
penetration hardness, for example 0.01 meters, the non-natural clay
composition would transfer 0.0095 grams of composition while the
natural clay-containing composition would transfer 0.021 grams of
composition. In order to more fully elaborate upon the unexpected
benefit of combining a natural clay or synthetic analog of a
natural clay with a rheology modifier, the relationship between
viscosity and shear rate was determined for various compositions of
the invention. Ideally, compositions applied to the bodyfacing
surfaces of absorbent articles have a high viscosity at the
stability-measuring temperature of 54.5.degree. C. and a low shear
rate in order to minimize migration of the composition away from
the bodyfacing surfaces. Previously, it was thought that if a
composition had a melting point greater than 55.degree. C., the
composition would not migrate. However, in reality, such
compositions would have components with melting points below the
bulk melting point of the composition. Those lower melting point
components would soften the composition and migration would occur.
Addition of the viscosity enhancers of the invention to
compositions results in significantly greater stability even when
the composition has a bulk melting point below 54.5.degree. C. Even
better stability is achieved when compositions include a rheology
modifier and a natural clay (or synthetic analog of a natural clay)
and, unexpectedly, and as shown by the Ink Rub Test results, the
compositions have improved transfer to the skin of the wearer of
the absorbent article.
[0135] FIG. 5 shows a plot of viscosity versus shear rate and
evidences the unexpected benefits provides by the compositions of
the invention. The viscosity of several compositions was measured
at 75.degree. C. over increasing shear rates The temperature of
75.degree. C. was selected to represent a processing temperature.
The compositions for which viscosity was measured are described in
Table 2 below.
2TABLE 2 Composition Composition Composition Composition Component
A B C Petrolatum 95% 97.4% 92.4% CLAYTON HY 2% 2% organomodified
clay Propylene 0.6% 0.6% Carbonate POLAR GEL NF 5% 5% natural
clay
[0136] CLAYTON HY is an organically modified clay that is available
from Southern Clay Corporation and represents a rheology modifier
of the invention. Propylene carbonate is an activator that
activates the organically modified clay POLAR GEL NF is a natural
clay that is available from American Colloid. The relationship
between viscosity and shear rate is plotted for compositions A-C in
FIG. 5. The relationship between viscosity and shear rate can be
defined by the following equations for each composition:
3 Composition A: y = 0.0384x.sup.-0 7163 Composition B: y =
0.6816x.sup.-0 8911 Composition C: y = 5.2332x.sup.-1.0574
[0137] The results portrayed in FIG. 5 show the synergistic benefit
of combining a rheology modifier with a natural clay (or a
synthetic analog of a natural clay). Composition A, including a
natural clay, has the lowest viscosity over the range of shear
rates. Composition B, including an organically modified clay, has
the next highest viscosity over the range of shear rates. However,
Composition C, including both an organically modified clay and a
natural clay, maintains the highest viscosity over the range of
shear rates. A similar set of experiments were conducted for
silica-containing compositions. The compositions are described in
Table 3. below.
4TABLE 3 Composition Component Composition A Composition B
Composition C Petrolatum 54.9% 57.9% 52.9% Microcrystalline Wax 40%
40% 40% Silica (M5) 2% 2% POLAR GEL NF 5% 5% Natural clay UV
Tracers 0.1% 0.1% 0.1%
[0138] The relationship between viscosity and shear rate for
compositions A-C (described in Table 3.) is depicted in FIG. 6. The
relationship between viscosity and shear rate can be defined by the
following equations for each composition:
5 Composition A: y = 0.3958x.sup.-0.5941 Composition B: y =
1.8522x.sup.-1 0518 Composition C: y = 13.191x.sup.-1.1664
[0139] Composition A, including a natural clay, has the lowest
viscosities over the range of shear rates. Composition B, including
silica, has a higher viscosity over the range of shear rates.
Composition C, including both silica and natural clay, has the
highest viscosities over the range of shear rates and exhibits
strong thixotropic behavior as evidenced by the large negative
exponential value. The combination of the rheology modifier,
silica, with a natural clay provides a synergistic beneficial
effect on the viscosities of the compositions of the invention.
Though viscosities increase, as described previously, the
compositions of the invention show improved transfer from a
liner-type material.
[0140] If it is desired that the composition provide a treatment
for the skin, the composition can also include an active ingredient
such as a diaper rash skin protectant. Skin protectants are drug
products that protect injured or exposed skin or mucous membrane
surface from harmful or annoying stimuli. Suitable active
ingredients, in addition to those mentioned above as suitable
emollients, that can be incorporated into the composition include,
but are not limited to, allantoin and its derivatives, aloe,
aluminum hydroxide gel, calamine, cocoa butter, dimethicone, cod
liver oil, glycerin, kaolin and its derivatives, lanolin and its
derivatives, mineral oil, petrolatum, shark liver oil, talc,
topical starch, zinc acetate, zinc carbonate, zinc oxide and the
like, and mixtures thereof. The composition may include from about
0.10 to about 95 percent by weight of the active ingredient
depending upon the skin protectant, the amount desired to be
transferred to the skin or the amount of a particular skin
protectant required in the U.S. Food and Drug Administration
monograph.
[0141] In order to better enhance the benefits to the wearer,
additional ingredients can be included in the compositions of the
present invention. For example, the classes of ingredients that may
be used and their corresponding benefits include, without
limitation: antifoaming agents (reduce the tendency of foaming
during processing); antimicrobial actives; antifungal actives;
antiseptic actives; antioxidants (product integrity);
antioxidants-cosmetic (reduce oxidation); astringents-cosmetic
(induce a tightening or tingling sensation on skin);
astringent-drug (a drug product that checks oozing, discharge, or
bleeding when applied to skin or mucous membrane and works by
coagulating protein); biological additives (enhance the performance
or consumer appeal of the product); colorants (impart color to the
product); deodorants (reduce or eliminate unpleasant odor and
protect against the formation of malodor on body surfaces); other
emollients (help to maintain the soft, smooth, and pliable
appearance of the skin by their ability to remain on the skin
surface or in the stratum corneum to act as lubricants, to reduce
flaking, and to improve the skin's appearance); external analgesics
(a topically applied drug that has a topical analgesic, anesthetic,
or antipruritic effect by depressing cutaneous sensory receptors,
or that has a topical counterirritant effect by stimulating
cutaneous sensory receptors); film formers (to hold active
ingredients on the skin by producing a continuous film on skin upon
drying); fragrances (consumer appeal); silicones/organomodified
silicones (protection, water resistance, lubricity, softness); oils
(mineral, vegetable, and animal); natural moisturizing agents (NMF)
and other skin moisturizing ingredients known in the art;
opacifiers (reduce the clarity or transparent appearance of the
product); powders (enhance lubricity, oil adsorption, provide skin
protection, astringency, opacity, etc.); skin conditioning agents;
solvents (liquids employed to dissolve components found useful in
the cosmetics or drugs); and surfactants (as cleansing agents,
emulsifying agents, solubilizing agents, and suspending
agents).
[0142] An important property of the compositions of the different
aspects of the present invention is their ability to remain on the
surface of the bodyside liner 22 and their resistance to migration
into the diaper 10 such that they can readily be transferred to the
wearer's skin. In this regard, the articles having the compositions
of the present invention applied to their bodyside liner 22 define
a z-direction migration loss of no more than about 55%, desirably
no more than about 50%, more desirably no more than about 45%, even
more desirably no more than about 40% and yet even more desirably
no more than about 35% when subjected to the Z-Direction Lotion
Migration Test set forth below. In articles that have a greater
z-direction migration loss, the composition undesirably migrates
into the interior and along the surface of the bodyside liner 22
and at times through the bodyside liner 22 into the absorbent body
24 of the article which results in a lower reduction in abrasion
and less transfer to the skin of the wearer.
[0143] Another important measure of the compositions of the
different aspects of the present invention is their ability to
resist migration laterally along the surface of the bodyside liner
22. In this regard, the articles having the compositions of the
present invention applied to the bodyside liner 22 define a
cd-direction migration loss of no more than about 40%, desirably no
more than about 35%, more desirably no more than about 30%, even
more desirably no more than about 25% and yet even more desirably
no more than about 20% when subjected to the CD-Direction Lotion
Migration Test set forth below. In articles which have a greater
cd-direction migration loss, the composition undesirably migrates
along the surface of the bodyside liner 22 and at times through the
bodyside liner 22 into the absorbent body 24 of the article which
results in a lower reduction in abrasion and less transfer to the
skin of the wearer.
[0144] Moreover, to provide the improved stability and transfer to
the skin of the wearer, the compositions of the present invention
may define a melting point of from about 32.degree. C. to about
100.degree. C., desirably from about 35.degree. C. to about
80.degree. C., and more desirably from about 40.degree. C. to about
75.degree. C. Compositions that have lower melting points exhibit
migration of the composition during use and at elevated
temperatures in storage that can undesirably result in reduced
transfer to the skin. Whereas, compositions that have higher
melting points may require that the composition be at a temperature
above the flash point of the bodyside liner 22 material which can
undesirably lead to fires. The melting points of the compositions
of the invention cause the compositions to be relatively immobile
and localized on the bodyfacing surface 11 of the diaper 10 at room
temperature and readily transferable to the skin of the wearer at
body temperatures. However, the compositions of the invention are
not completely liquid under extreme storage conditions. Desirably,
the compositions are easily transferable to the skin by way of
normal contact, wearer motion, adhesion or body heat. When the
compositions are relatively immobilized at room temperature, a
lesser quantity of composition is required on the bodyfacing
surface 11 to provide a beneficial effect.
[0145] The composition of the present invention may further define
a low shear viscosity at about 55.degree. C. of greater than about
50,000 centipoise, desirably from about 50,000 to about 1,000,000
centipoise, and more desirably from about 100,000 to about 800,000
centipoise for reduced migration and improved transfer to the skin
of the wearer. Compositions that have lower melt point viscosities
exhibit migration of the composition through the bodyside liner 22
into the absorbent body 24 of the article which can undesirably
result in reduced transfer to the skin. Whereas, compositions that
have higher melt point viscosities may be so solid as to also
exhibit a reduced transfer to the skin.
[0146] Further, to provide the improved stability and transfer to
the skin of the wearer, the compositions of the present invention
may also define a high shear viscosity of less than about 5,000
centipoise, desirably from about 100 to about 500 centipoise, and
more desirably from about 150 to about 250 centipoise at a
temperature of about 60.degree. C. (or higher temperatures
depending on the components and melting point of the
composition).
[0147] The penetration hardness of the compositions of this
invention can be from about 5 to about 365 millimeters, more
desirably from about 10 to about 300 millimeters, more desirably
from about 20 to about 200 millimeters, and still more desirably
from about 40 to about 120 millimeters at 25.degree. C.
(Compositions having a needle penetration hardness greater than 365
millimeters cannot be measured using ASTM method D 1321). The
hardness of the compositions of this invention is important for two
reasons. First, the softer the formulation the more mobile the
formulation will be, making the formulation more likely to migrate
to the inner plies of the diaper 10, which is not desirable.
Secondly, softer compositions tend to be more greasyloily to the
touch, which is also less desirable.
[0148] The composition may be applied to the entire bodyfacing
surface 11 of the bodyside liner 22 or may be selectively applied
to particular sections of the bodyfacing surface 11, such as the
medial section along the longitudinal centerline of the diaper 10,
to provide greater lubricity of such sections and to transfer such
composition to the wearer's skin. Alternatively, the bodyfacing
surface 11 of the bodyside liner 22 may include multiple stripes of
the composition applied thereto as illustrated in FIG. 3. For
example, the bodyfacing surface 11 of the bodyside liner 22 may
include from 1 to 20 stripes 54 of composition extending along the
longitudinal direction of the diaper 10. The stripes 54 may extend
the full length of the bodyside liner 22 or only a portion thereof.
The stripes 54 may also define a width of from about 0.2 to about 1
centimeters.
[0149] The composition should cover a sufficient amount of the
bodyfacing surface 11 of the bodyside liner 22 to ensure adequate
transfer to the skin and reduced abrasion between the bodyside
liner 22 and the wearer's skin. Desirably, the composition is
applied to at least about 5 percent and more desirably at least
about 25 percent of the bodyfacing surface 11 of the bodyside liner
22.
[0150] The composition can be applied to the bodyside liner 22 at
any add-on level that provides the desired transfer benefit. For
example, the total add-on level of the composition can be from
about 0.05 to about 100 mg/cm.sup.2, desirably from about 1 to
about 50 mg/cm.sup.2 and more desirably from about 10 to about 40
mg/cm.sup.2 for improved performance. The add-on amount will depend
upon the desired effect of the composition on the skin barrier
function and the specific composition. As discussed above, the
improved stability and reduced tendency to migrate of the
compositions of the present invention allows a lesser amount of
composition to be applied to the bodyside liner 22 to achieve the
same benefit when compared with conventional compositions.
[0151] The composition may be applied to the bodyside liner 22 in
any of many well known manners. A preferred method to uniformly
apply the composition to the bodyfacing surface 11 of the bodyside
liner 22 is spraying or slot coating. Spraying or slot coating the
composition is the most exact process and offers maximum control of
the composition distribution and transfer rate. However, other
methods, such as rotogravure or flexographic printing and foam
application can be used. The compositions of the present invention
can be applied after the bodyfacing material has been incorporated
into the absorbent article or prior to incorporating the body
facing material into the absorbent article.
[0152] The composition may be applied to the bodyside liner 22 by
(a) heating the composition to a temperature above the melting
point of the composition, causing the composition to melt, (b)
uniformly applying the melted composition to the bodyfacing surface
11 of the bodyside liner 22; and (c) resolidifying the composition
applied to the bodyfacing surface 11. Desirably, resolidification
of the composition occurs almost instantaneously, without the need
for external cooling devices such as chill rolls. This can occur if
the composition is heated to a temperature only slightly above or
at the melting point of the composition. However, external cooling
devices such as chill rolls, either before or after the application
of melt, can be used if desired to accelerate resolidification.
Other cooling methods such as cooling tunnels could also be
used.
[0153] The increased viscosity of the composition at the process
temperature and the instantaneous resolidification tends to impede
penetration of the composition into the bodyside liner 22 and
absorbent body 24 of the diaper 10 and retain it on the bodyfacing
surface 11 of the bodyside liner 22, which is advantageous. For
example, the temperature of the melted composition can
advantageously be less than about 10.degree. C., more desirably
less than about 5.degree. C., and still more desirably less than
about 2.degree. C. above the melting point of the composition prior
to applying it to the bodyside liner 22 for reduced migration. As
the temperature of the melted composition approaches the freezing
point of the composition, the viscosity of the melted composition
generally increases, which further enhances the tendency of the
melted composition to be retained on the bodyfacing surface 11.
[0154] The present invention is also directed to an absorbent
article, such as a diaper 10, that includes an outer cover 20, a
liquid permeable bodyside liner 22, an absorbent body 24 and a
composition. The bodyside liner 22 defines a bodyfacing surface 11.
As already described herein, the bodyfacing surface 11 is that
portion of the article that comes into contact with the skin of the
wearer or user of the article. When the article is a diaper 10, the
bodyfacing surface 11 typically is primarily the bodyside liner 22,
but the bodyfacing surface 11 can also include waist and leg
elastics 26, 28, containment flaps and fasteners 30. When the
article is a primarily two-dimensional substrate such as a tissue
or wet wipe, the entire surface area of the tissue or wet wipe is
the bodyfacing surface 11 as any portion of such articles may
contact the user's skin.
[0155] The bodyside liner 22 is in superposed relation to the outer
cover 20. The absorbent body 24 is located between the bodyside
liner 22 and the outer cover 20. At least a portion of the
bodyfacing surface 11 of the bodyside liner 22 has a composition on
it. The composition includes from about 0.5 to about 75 percent by
weight of natural fats or oils. The natural fats and oils can be
selected from avocado oil, borage oil, sunflower oil, soybean oil,
corn oil, cottonseed oil and mixtures of these compounds. The
composition also includes from about 0.5 to about 5 percent by
weight of sterols or sterol derivatives. The sterols and sterol
derivatives can be selected from cholesterol, sitosterol,
stigmasterol, tall oil sterol, soy sterol and mixtures of these
compounds. Additionally, the composition includes from about 20 to
about 75 percent by weight of one or more emollients. The
emollients can be selected from petrolatum, silicone oils,
dimethicone, lanolin and mixtures of these compounds. The
composition may also include from about 25 to about 75 percent by
weight of one or more solidifying agents. The solidifying agents
may be selected from cerasin, microcrystalline wax, ozokerite,
alkylmethylsiloxanes including alkyl silicones and mixtures of
these compounds. The composition also includes from about 5 to
about 40 percent by weight of one or more viscosity enhancers. The
viscosity enhancers can be selected from ethylene/vinyl acetate
copolymers, polyethylene, silica and mixtures of these compounds.
The composition further includes from about 0.1 to about 20 percent
by weight of one or more decoupling polymers. The decoupling
polymers can be selected from polymers having a hydrophilic
backbone with one or more hydrophobic side-chains including
homopolymers of acrylic acid, acrylic acid/maleic acid copolymers,
poly(2-hydroxy ethyl acrylate), polysaccharides, cellulose ethers,
polyglycerols, polyacrylamides, polyvinylalcohol/polyvi- nylether
copolymers, poly(sodium vinyl sulphonate), poly(2-sulphato ethyl
methacrylate) and poly(acrylamidomethylpropane sulphonate) and
mixtures of such polymers.
[0156] The composition has physical properties that are suitable to
provide a relative degree of immobilization on the bodyfacing
surface 11 at room temperature and to provide sufficient fluid or
transfer properties at body temperature so that the composition can
migrate to the skin. Typically, the composition has a melting point
of from about 32.degree. C. to about 100.degree. C. and a high
shear viscosity less than about 5,000 centipoise at a temperature
of about 60.degree. C. The composition has a low shear viscosity of
greater than about 50,000 centipoise at a temperature of about
55.degree. C. The composition may also have a penetration hardness
of from about 5 millimeters to about 365 millimeters at 25.degree.
C. The composition is typically present on the bodyfacing surface
11 in an amount of from about 0.1 g/m.sup.2 to about 30 g/m.sup.2.
The composition applied to the bodyfacing surface 11 may have
additional ingredients added to it in order to provide additional
benefits or to enhance the functionality and processability of the
composition.
[0157] The present invention is also directed to a method of
applying a composition to a bodyfacing surface 11 of a bodyside
liner 22 of an absorbent article. The method includes a step of
heating a composition to a temperature above the melting point of
the composition. The composition generally protects the skin
barrier and reduces inflammation and may include an emollient, a
viscosity enhancer and a decoupling polymer. The composition may
also include natural fats or oils, sterols or sterol derivatives,
solidifying agents, rheology modifiers and clays. The melting point
of the composition is from about 32.degree. C. to about 100.degree.
C. The method also includes a step of applying the composition to
the bodyfacing surface 11 of a bodyside liner 22 of an absorbent
article. The method further includes a step of resolidifying the
composition. The composition can be applied to the bodyfacing
surface 11 using any of the techniques already describe herein such
as foam application, spraying, slot coating and printing. The
composition can be resolidified using devices that are commonly
used for cooling, such as chill rolls and cooling tunnels, or the
composition can be resolidified or become very viscous by selecting
a combination of ingredients that puts the melting point or high
viscosity close to the processing temperature. When the melting
point of the composition is close to the processing temperature,
the composition should quickly resolidify or become very viscous
after application to the bodyfacing surface 11. Typically, after
resolidification, the composition has a viscosity of greater than
about 50,000 centipoise and a penetration hardness of from about 5
to about 365 millimeters at 25.degree. C.
[0158] The present invention is further directed to a method for
protecting the skin barrier on a skin surface of a user. The method
includes a step of contacting a skin surface of a user of an
absorbent article with a bodyfacing surface 11 of a bodyside liner
material. The method could also include a step of contacting the
skin surface of a user of a tissue or wet wipe article with the
outer surface of the material from which the tissue or wet wipe is
constructed. The bodyfacing surface 11 or outer surface has a
composition on it. The composition may include an emollient, a
viscosity enhancer and a decoupling polymer. The relative amounts
and combinations of composition components can be varied. The
method of the invention also includes a step of maintaining the
bodyfacing surface 11 in contact with the skin surface of the user
for a sufficient amount of time to transfer the composition to the
skin surface. The amount of time is related to the nature of the
composition and its physical properties; different compositions
will transfer to a skin surface at different rates. The method
further includes a step of repeating the maintaining step for a
sufficient period of time to provide a benefit to the skin barrier
function. Therefore, the method includes repeating the contact of
the skin surface with the bodyfacing surface 11 of the liner
material.
[0159] As suggested by the compositions already described herein,
the composition applied to the bodyfacing surface 11 can include
from about 40 to about 95 percent by weight of one or more
emollients, from about 1 to about 40 percent by weight of one or
more viscosity enhancers and from about 0.1 to about 20 percent by
weight of one or more decoupling polymers. Examples of suitable
emollients, viscosity enhancers and decoupling polymers are as
described herein.
[0160] The descriptions of the articles and compositions of the
invention provided herein have included references to various tests
for assessing the attributes or properties of the components of the
articles and compositions as well as the articles and compositions
in their entireties. Descriptions of the test procedures used to
make those assessments are now provided.
[0161] Hydrostatic Pressure Test
[0162] The Hydrostatic Pressure Test is a measure of the liquid
barrier properties of a material. In general, the Hydrostatic
Pressure Test determines the height of water (in centimeters) in a
column that the material will support before a predetermined amount
of water passes through. A material with a higher hydrohead value
indicates it is a greater barrier to liquid penetration than a
material having a lower hydrohead value. The Hydrostatic Pressure
Test is performed according to Method 5514--Federal Test Methods
Standard No. 191A.
[0163] Frazier Porosity Test
[0164] The Frazier Porosity values referred to in the present
specification can be determined employing a Frazier Air
Permeability Tester (Frazier Precision Instrument Co.,
Gaithersburg, Maryland) and Method 5450, Federal Test Methods
Standard No. 191A. For the purposes of the present invention, the
test is conducted with a sample that measures 8 inches.times.8
inches.
[0165] Water Vapor Transmission Test
[0166] A suitable technique for determining the WVTR (water vapor
transmission rate) value of a material is as follows. For the
purposes of the present invention, 3-inch diameter (76 millimeter)
circular samples are cut from the test material and from a control
material, CELGUARD 2500 material (Hoechst Celanese Corporation).
Two or three samples are prepared for each material. Test cups used
for testing are cast aluminum, flanged, 2 inches deep and come with
a mechanical seal and neoprene gasket. The cups are distributed by
Thwing-Albert Instrument Company, Philadelphia, Pa., under the
designation "Vapometer cup #681". One hundred milliliters of
distilled water are poured into each Vapometer cup, and each of the
individual samples of the test materials and control material are
placed across the open top area of an individual cup. Screw-on
flanges are tightened to form a seal along the edges of the cups
leaving the associated test material or control material exposed to
the ambient atmosphere over a 62 millimeter diameter circular area
(an open, exposed area of about 30 cm.sup.2). The cups are then
weighed, placed on a tray, and set in a forced air oven set at
100.degree. F. (38.degree. C.). The oven is a constant temperature
oven with external air circulating through it to prevent water
vapor accumulation inside. A suitable forced air oven is, for
example, a Blue M Power-O-Matic 60 oven distributed by Blue M
Electric Co. of Blue Island, Ill. After 24 hours, the cups are
removed from the oven and weighed. The preliminary, test WVTR value
is calculated as follows: 1 Test WVTR = [ ( grams weight loss over
24 hours ) .times. 7571 ] 24 ( g / m 2 / 24 hours )
[0167] The relative humidity within the oven is not specifically
controlled. Under predetermined set conditions of 100.degree. F.
and ambient relative humidity, the WVTR for CELGUARD 2500 materials
has been determined to be 5000 g/m.sup.2/24 hours. Accordingly,
CELGUARD 2500 material is run as a control sample with each test.
CELGUARD 2500 material is a 0.0025 cm thick film composed of a
microporous polypropylene.
[0168] Z-Direction Composition Migration Test
[0169] This test determines the quantity of composition that
remains on the target area of the bodyfacing surface of an
absorbent article after a given period of time at a given
temperature. Specifically, the purpose of the test is to compare
the amount of composition present in the target zone on articles
stored at a lower temperature with that present on articles stored
at a higher temperature. The test simulates storage at elevated
temperature conditions to which absorbent articles may be
subjected. For example, such articles may be stored in the trunk of
a vehicle or in a warehouse in a warm climate such as in a
warehouse in Arizona in July or August. The z-direction migration
loss is a measure of the composition migration after storage at
130.degree. F. when compared to the composition migration at
73.degree. F. after a fixed period of time. Thus, this test
predicts the amount of composition that will be available on the
bodyfacing surface of the article for transfer to the skin when the
article is used as well as how quickly it will undesirably migrate
away from or along the bodyfacing surface of the article in
use.
[0170] Specifically, the test is conducted as follows:
[0171] 1. Ten (10) products having a composition applied to the
topsheet or bodyside liner are obtained.
[0172] 2. Five (5) products are placed in a controlled environment
at a temperature of 73.degree. F. and a relative humidity of 50%
for a fixed period of time such as, for example, 28 days. The other
five (5) products are placed in a controlled environment at a
temperature of 130.degree. F. and ambient humidity for the same
period of time.
[0173] 3. The products are removed from the controlled environment
and a sample of the bodyside liner having a width of 3.75 inches
and a length of 13 inches is removed from the center of each
product.
[0174] 4. The samples are then subjected to Soxhlet Extraction with
Gravimetric Analysis (SEGA) as follows. The test apparatus includes
a reboiler, chloroform vapor duct, cold water condenser, holding
tank where the samples are placed and a chloroform recycle duct.
The components of the test apparatus are conventional glassware
well known to those skilled in the art. For example, the reboiler
may include a 250 ml round bottom flask and the vapor duct can
include an 85 ml soxhlet. A sample is placed in the holding tank
and subjected to chloroform washing cycles for 2.5 hours. One
hundred twenty-five milliliters of liquid chloroform is placed in
the reboiler. The chloroform vaporizes and rises up through the
vapor duct into the condenser having tap water therein that, in
turn, causes the chloroform to liquefy and fall into the holding
tank with the sample. The chloroform dissolves the composition from
the liner sample. When the liquid chloroform reaches a high enough
level, the recycle duct returns the chloroform/composition mixture
to the reboiler. The temperature in the reboiler is controlled such
that it is above the boiling point of the chloroform but below that
of the composition such that only the chloroform vaporizes to start
the process over again. One complete wash cycle takes approximately
15 minutes with about 75 milliliters of chloroform circulating
through the liner sample in each cycle. Upon completion, the
chloroform in the evaporator is evaporated utilizing a conventional
vacuum evaporator such as a rotovap commercially available under
the model number Buchi 011 RE 121 for a period of 4 minutes
followed by placing the composition in an aluminum pan and heating
on a hot plate with forced air circulation for an additional 30
minutes.
[0175] 5. The residue (composition) remaining for each sample is
then weighed. The amount of composition recovered from the products
stored at 73.degree. F. is then compared to the amount of
composition recovered from the products stored at 130.degree. F. to
determine the stability of the composition formulation at high
temperature.
[0176] The z-direction migration loss of the absorbent article is
then determined as follows:
[0177] Z-direction migration loss
(%)=[(L.sub.73-L.sub.130)/L.sub.73].time- s.100
[0178] wherein,
[0179] L.sub.73=average weight (g) of composition recovered per
sample stored at 73.degree. F.
[0180] L.sub.130=average weight (g) of composition recovered per
sample stored at 130.degree. F.
[0181] CD-Direction Composition Migration Test
[0182] This test determines the quantity of composition that
remains on the specific location where it is applied on the
bodyfacing surface of an absorbent article after a given period of
time at a given temperature. Specifically, the purpose of the test
is to compare the amount of composition present in the applied
location on the topsheet or bodyside liner with that present on the
remaining portions of the bodyside liners of the articles after
being stored at an elevated temperature. The test simulates storage
at elevated temperature conditions to which absorbent articles may
be subjected. For example, such articles may be stored in the trunk
of a vehicle or in a warehouse in a warm climate such as in a
warehouse in Arizona in July or August. The cd-direction migration
loss is a measure of the lateral composition migration along the
bodyfacing surface of the article after storage at 130.degree. F.
after a fixed period of time. Thus, this test predicts the amount
of composition that will be available in the desired location on
the bodyfacing surface of the article for transfer to the skin when
the article is used as well as how quickly it will undesirably
migrate away from or along the bodyfacing surface of the article in
use.
[0183] Specifically, the test is conducted as follows:
[0184] 1. Five (5) products having a composition applied to the
bodyside liner in a specific pattern are obtained.
[0185] 2. The products are placed in a controlled environment at a
temperature of 130.degree. F. and ambient humidity for a fixed
period of time such as, for example, 28 days.
[0186] 3. The products are removed from the controlled environment
and the bodyside liner on each product is removed and dissected to
remove the portion of the bodyside liner to which the composition
was actually applied. For example, if the composition was applied
as 4 continuous lines having a width of 0.25 inches with spaces of
0.75 inches in between, the 4 strips of bodyside liner would be
removed.
[0187] 4. The samples which include the portions of the bodyside
liner to which the composition was applied are then grouped
together and subjected to Soxhlet Extraction with Gravimetric
Analysis (SEGA) as described above. The remaining portions of the
bodyside liner are also grouped together and subjected to a
separate SEGA extraction.
[0188] 5. The residue (composition) remaining for each group is
then weighed. The amount of composition recovered from the portions
of the bodyside liner to which the composition was applied is then
compared to the amount of composition recovered from the remaining
portions of the bodyside liner to determine the stability of the
composition at high temperature.
[0189] The cd-direction migration loss of the absorbent article is
then determined as follows:
[0190] CD-direction migration loss
(%)=[L.sub.sp/(L.sub.a+L.sub.sp)].times- .100
[0191] wherein,
[0192] L.sub.sp=average weight (g) of composition recovered from
the portions of the bodyside liner to which the composition was not
applied per diaper
[0193] L.sub.a=average weight (g) of composition recovered from the
portions of the bodyside liner to which the composition was applied
per diaper
[0194] The compositions of the present invention can be further
described through examples of compositions considered to be within
the scope of the present invention. The examples provided herein
are intended to be representative of the present invention but are
not intended to delineate the extent of the present invention. To
the extent that amounts of individual components or total
compositions are referred to in terms of "effective amounts",
"effective amount" is understood to mean an amount that will have
the desired effect of that component or composition. For example,
an "effective amount" of one of the compositions of the invention
is understood to mean an amount that, when applied to the
bodyfacing or skin contacting surface of an article, will protect
the barrier of the skin or reduce inflammatory response.
Illustrative examples of the compositions of the invention are
provided in Table 4. below.
6TABLE 4 Formula (weight percent) 1 2 3 4 Petrolatum 50% 55% 51%
64% Ozokerite Wax 43% 33% 30% -- Ethylene Vinyl Acetate Copolymer
5% 5% 10% 25% NARLEX DC-1 polymer 1% 5% 8% 10% EMEREST 2452
surfactant 1% 2% 1% 1% Formula (weight percent) 5 6 7 8 Petrolatum
55% 55% 45% 40% Microcrystalline Wax 36.5% 25% 46.25% 47% Ethylene
Vinyl Acetate Copolymer 7% 8% 5% 5% ACULYN R33 polymer 1% 10% -- --
RHEOTHIX 80-11 polymer -- -- 3% 7% Cetyl Dimethicone Copolymer
0.50% 2% 0.75% 1% Formula (weight percent) 9 10 11 12 Petrolatum
40% 42% 47% 68% Cerasin 35% 30% 25% 22% Ethylene Vinyl Acetate
Copolymer 5% 5% -- 3% Propylene Glycol 5% 5% -- -- Glycerin 2% 2%
-- -- NARLEX DC-1 polymer 3% 6% -- -- RHEOTHIX 80-11 polymer -- --
1% 5% BENTONE TN Organically 10% 10% -- -- Modified Clay Silica --
-- 2% 2% Zinc Oxide -- -- 25% -- Formula (weight percent) 13 14 15
16 Petrolatum 15% 5% -- -- Myristyl Myristate 17% 25% 30% 33%
Behenyl Benzoate -- 35% 20% 30% Behenyl Behenate 50% -- 5% --
C12-C15 Alkyl Benzoate -- 7% 20% 5% Ethylene Vinyl Acetate
Copolymer 5% 3% 2% 2% Octyl Dodecanol -- 10% 5% 5% Silica -- 2% 3%
5% Avocado Oil -- -- -- 5% ACULYN R33 polymer 10% -- -- -- RHEOTHIX
80-11 polymer -- 10% -- -- NARLEX DC-1 polymer -- -- 10% --
Sorbitan Trioleate 3% 3% 5% 5% Formula (weight percent) 17 18 19 20
Petrolatum 64% 53% 48% 40% Cerasin 5% 10% 25% 30% Glycerin 5% 8%
10% 3% Sunflower Oil 10% -- -- -- Echium Oil -- 5% -- -- Borage Oil
-- -- 3% -- Rapeseed Oil -- -- -- 5% Soy Sterol 1% -- -- --
Cholesterol -- 3% -- -- AVOCADIN extract -- -- 5.00% 10% PROLIPID
141 Blend 2% 1% -- -- Glyceryl Stearate SE -- -- 3% 2% BENTONE TN
Organically 10% 15% -- -- Modified Clay Silica -- -- 4% 2% NARLEX
DC-1 polymer 3% -- -- 2% ACULYN R-33 polymer -- 5% -- -- RHEOTHIX
80-11 polymer -- -- 2% 6%
[0195] The decoupling polymers are available from numerous
suppliers. For example, NARLEX DC-1 polymer is available from
National Starch and Chemical Co. ACULYN R-33 polymer is available
from Rohm & Haas company. RHEOTHIK 80-11 polymer is available
from Cognis Corporation.
[0196] As used herein, all recited ranges of amounts, temperatures,
molecular weights and penetration hardnesses are intended to
include all sub-ranges within the recited ranges, even though not
specifically stated. The following examples are presented to
provide a more detailed understanding of the invention.
[0197] In order to evaluate the efficacy of the compositions of the
invention, a human skin culture was selected to model the response
of the human epidermis. EPIDERM skin culture is a cornified,
air-interfaced human skin culture. EPIDERM skin culture has
multiple layers of progressively differentiated keratinocytes
resembling human epidermis. EPIDERM EPI-200 skin culture can be
purchased from MatTek Corporation of Ashland, Mass. Experiments
using EPIDERM skin culture are conducted in six well plates.
Typically, five EPIDERM skin culture inserts are added to five of
the six wells. Each well contains one milliliter of pre-warmed
media that is the same as the EPIDERM skin culture media. The
plates are then incubated in a 37.degree. C., 5% CO.sub.2 incubator
for thirty minutes. After incubation, 15 microliters of test
composition or control are applied to the surface of the EPIDERM
skin culture after removing any residual media. For test
compositions using a petrolatum base, the composition is applied
using a positive-displacement pipettor and spread over the skin
culture surface using a glass rod. The well plates, with the test
compositions/control applied, are incubated in the 37.degree. C.,
5% CO.sub.2 incubator for thirty minutes after which the underlying
media is removed and replaced with fresh, pre-warmed media. Next,
ten microliters of insult solution, either fecal protease or bile
acid, are applied to the surface of the EPIDERM skin culture.
[0198] Infant feces contain proteases that include trypsin and
chymotrypsin (See Haverback, B. J., Dyce, B. J., Gutentag, P. J.,
and Montgomery, D. W. (1963) Measurement of Trypsin and
Chymotrypsin in Stool. Gasteroenterology 44:588-597; and Barbero,
G. J., Sibinga, M. S., Marino, J. M., and Seibel, R. (1966) Stool
Trypsin and Chymotrypsin. Amer. J. Dis. Child 112:536-540). For
internal studies, infant feces were collected and the amount of
total protease and trypsin activities determined for each of the
fecal extracts. To prepare the extract, the feces were suspended in
water and vigorously vortexed. After vortexing, the samples were
held on ice prior to centrifugation at 15,000 times the force of
gravity for 20 minutes. The supernatant was filtered through 0.22
micron cellulose acetate filters and stored at -80.degree. C. until
use. The amount of trypsin activity in the fecal extracts ranged
from 0.4-402 .mu.g/mi (n=19) as measured by the ability of the
sample to hydrolyze a fluorescently-labeled trypsin peptide
substrate (Boc--Gln--Ala--Arg--AMC HCI, BACHEM California,
Incorporated, Torrance, Calif.). Total protease activity was
measured as the ability of the sample to hydrolyze a fluorescent
dye-labeled casein substrate (EnzChek Protease Assay Kit (E-6639),
Molecular Probes, Eugene, Oreg.). Irritation induced in the EPIDERM
skin culture correlated with the total protease as well as trypsin
activities of the fecal extracts. Based on the literature sources
as well as internal data, a trypsin-chymotrypsin insult was chosen
as representative of a fecal insult, specifically a fecal protease
insult, for the examples that follow.
[0199] The insult solution is prepared by diluting a 10 mg/ml stock
solution in phosphate-buffered saline to a working concentration of
250 g/ml. The base of the stock solution is 50 mM NaOAcetate, pH
5.5 and 0.15 M NaCl stored at -80.degree. C. One milliliter of the
stock protease insult solution contains 2558 USP units of trypsin
and 298 USP units of chymotrypsin and is available from Specialty
Enzymes, Inc. of Chino, Calif. The bile acid insult solution can be
prepared by dissolving 65 mg of cholic acid 62 mg of deoxycholic
acid and 31 mg of chenodeoxycholic acid in 10 ml of
phosphate-buffered saline. The bile acid insult components can be
purchased from Sigma Chemical Co. of St. Louis, Mo.
Phosphate-buffered saline, pH 7.4 (hereinafter "PBS") can be
purchased from Life Technologies of Rockville, Md.
[0200] After application of the insult solution, the well plates
are incubated for six hours in the 37.degree. C., 5% CO.sub.2
incubator. At the end of six hours, the well plates are removed
from the incubator, the underlying media is removed and stored at
-80.degree. C. The response of the EPIDERM skin culture to the test
compositions/control and the insult solution is determined by
measuring the amount of interleukin-1 alpha (referred to hereon as
"IL-1"). Interleukin-1 alpha can be quantified using an
Interleukin-1 alpha Quantikine Kit available from R&D Systems
of Minneapolis, Minn. Interleukin-1 alpha measurements are
converted to Log.sub.10 for each of the treatments and the averages
for each treatment are calculated. In order to determine the
ability of the test compositions to reduce skin irritation caused
by the biological insults, the percent mean reduction of IL-1 i s
calculated as follows: 2 % mean reduction of IL - 1 = 100 .times. (
( PJ control + insult ) result - ( test composition + insult )
result ) ( ( PJ control + insult ) result - ( PJ control + PBS )
result )
[0201] (Test composition+insult) result=the measured amount of IL-1
from treatment with a test composition+insult.
[0202] (PJ control+insult) result=the measured amount of IL-1 from
a treatment with a control formulation+insult.
[0203] (PJ control+PBS) result=the measured amount of IL-1 from a
treatment with a control formulation with PBS.
[0204] The greater the % mean reduction of IL-1 the more effective
a composition is at reducing irritation caused by the biological
insult (proteases or bile acids).
[0205] In order to insure that the test compositions/control do not
affect the viability of the EPIDERM skin culture, a MTT assay is
run. The MTT dye is taken up by the cells. The reduction of the dye
as a result of cellular metabolism can be used to measure the
cytotoxicity of the test compositions. In order to confirm
viability, inserts of the EPIDERM skin culture that have already
been subjected to the test compositions and biological insults are
removed from their media and are washed consecutively through
immersion in three different beakers of PBS. Fresh PBS is used for
each test composition or control being evaluated. The PBS is
discarded onto paper towel. The EPIDERM skin culture inserts are
then patted onto paper towel and placed into the wells of a 24 well
plate containing 300 microliters of pre-warmed media. After all of
the EPIDERM skin culture inserts are washed, they are transferred
to new 24 well plates containing 300 microliters of the MTT
reagent. The MTT reagent is thiazolyl blue having the formula
3-[4,5-Dimethylthiazol-2-yl]-2,5-diphen- yltetrzoliumbromide. The
plates are incubated for 2 hours in a 37.degree. C., 5% CO.sub.2
incubator. After incubation, the EPIDERM skin culture inserts are
transferred to 24 well plates and are immersed in 2 milliliters of
MTT extraction buffer. The extraction buffer extracts the MTT
reagent from the cells. The 24 well plates are parafilmed, covered
and placed in ZIPLOCK bags to reduce evaporation of the extraction
buffer. The covered plates are rocked overnight in the dark.
Following overnight rocking, the liquid in the EPIDERM skin culture
inserts is decanted back into the wells. The contents of each well
are mixed and a 200 microliter aliquot is then removed from each
well and transferred to a 96 well plate. The optical density (OD)
of the samples is measured at 570 nm using a spectrophotometer.
Five hundred seventy nanometers is the optimal wavelength at which
to measure the reduced form of MTT reagent. This reading is
subtracted from a background reading at 650 nm to improve data
quality. Percent viability of each test composition+insult relative
to a negative petrolatum control+PBS is recorded as the Mean
OD.sub.test composition+insult divided by the Mean OD.sub.PJ
control+PBS; the quotient then multiplied by 100.
[0206] EPIDERM skin culture studies were conducted to measure the
reduction in IL-1 response between compositions of the invention
and a fecal protease-induced irritation. The studies were conducted
using polymers that are representative of the invention. The
EPIDERM skin culture studies and associated MTT assays were
conducted as already described herein and the results are as
reported in Table 5. below.
7TABLE 5 Mean Reduction of Polymer Component Interleukin-1 Alpha
Viability Composition of Composition (percentage) (percentage) A 2%
AP-1-a 53% (5) 101% B 2% AP-3 0% (5) 99% C 1% AP-4 0% (5) 96% D 6%
AP-1-b 23% (5) 95% E 6% AP-1-b with 27% (5) 108% EMERSET 2452
emulsifier F 6% AP-1-b with 0% (5) 98% ABIL EM90 emulsifier
[0207] AP-1=NARLEX DC-1 C.sub.12 alkyl polyacrylate polymer
available from National Starch and Chemical Co. AP-1-a and AP-1-b
have concentrations of 20% and 33%, respectively
[0208] AP-3=ACULYN-R 33 polymer is a solution, 5% by weight, of
partially crosslinked acrylate polymer available from Rohm and
Haas.
[0209] AP-4=RHEOTHIK 80-11 polymer is a solution, 10% by weight, of
high molecularweight poly (sulfonic acid) polymer available from
Cognis Corporation.
[0210] EMERSET 2452 is a low HLB surfactant. The make-up of the
compositions in Table 5. is provided in Table 6. below.
8TABLE 6 % EMERSET % % Polymer % 2452 ABIL EM90 Polymer Solution
Petrolatum surfactant emulsifier 2% AP-1-a 20% 80% 0% 0% 2% AP-3
20% 79% 1% 0% 1% AP-4 20% 79% 1% 0% 6% AP-1-b 20% 80% 0% 0% 6%
AP-1-b 20% 79% 1% 0% EMERSET 2452 6% AP-1-b 20% 79% 0% 1% ABIL
EM90
[0211] The IL-1 reduction results of Table 5. show that the
compositions of the invention provide a skin protectant effect as
evidenced by a reduced irritation response. Suppliers of the
polymers provide the polymers as aqueous solutions. As seen by the
results in Table 5., not all of the polymers tested showed activity
with the EPIDERM skin culture test. Without intending to be bound
by theory, it is believed that these polymers would reduce the
irritation response of skin if they were delivered in a different
formulation. The formulations tested may have interfered with the
availability of negative charges at the surface of the polymer
emulsion droplets. Similarly, it is believed that the
surfactants/emulsifiers used could have interfered with the polymer
emulsion interface.
[0212] The reduction of IL-1 results were analyzed to statistically
identify "outlier" results. The EPIDERM skin culture is known to be
variable with the variability attributed to differences in the
culture, variation in the application of treatment and other
uncontrollable factors. A statistical analysis technique was
applied to identify when a result abnormally deviated from the rest
of the data set. The irritation values were first converted to
Log10 in order to make them more Gaussian (bell curve-shaped).
After conversion, the values were analyzed for high or low value
outliers; subsequently, the values were analyzed with a student's
t-test to identify significant differences from the "control". The
statistical analysis used to identify "outliers" is described on
page 460 of the book, "Statistical Methods in Research and
Production" edited by Owen L. Davies and Peter L. Goldsmith,
published by Longman Group Limited, fourth revised edition
published in 1984.
[0213] The compositions of the invention were also evaluated for
their efficacy in a clinical study. The study was directed to
measuring the erythema response to application of an "insult" and
application of compositions of the invention. The control
compositions were 100% petrolatum and 100% irritant mixture. The
test compositions contained from 0.2% to 16.8% polymer; 0.8%
preservatives/stabilizers including propyl paraben, methyl paraben,
disodium EDTA, BHT and NaCI; and a balance of petrolatum. The panel
size for the clinical study was a minimum of 17 adult males and
females. The control and test compositions were applied to areas on
the backs of the adults. Up to sixteen sites on each adult's back
were used for the study. Each test site was 2.5 cm in diameter. The
irritant mixture included trypsin, chymotrypsin and bile acid in
phosphate-buffered saline at a total concentration of 1500 g/ml.
The irritant mixture was either freshly prepared or refrigerated at
-80.degree. C. and defrosted at 37.degree. C. just prior to use and
then held in an ice bath. For each application of the irritant
mixture, 0.2 ml of the irritant mixture was placed into a 25 mm
HILLTOP chamber. Thirty milligram portions of the petrolatum
control and test compositions were applied to the selected sites on
each participant's back for twenty minutes. After application of
the test compositions, the HILLTOP chambers with the irritant
mixture were taped onto each test site and the petrolatum control
site for 24 hrs.; an extra chamber was applied to a previously
untreated site for 100% irritant mixture control. After 24 hrs.,
the HILLTOP chambers were removed. After an additional thirty
minutes, experts evaluated the control and test sites for erythema,
edema and dryness. The experts evaluated the sites using a scoring
scale of 0 to 4 with 0.5 point intervals. The score given for each
site was a combined evaluation for erythema, edema and dryness. The
data recorded by the experts was analyzed using a Nonparametric
Wilcoxon signed rank test statistical treatment to determine
significant differences between two sites and, therefore, between
two compositions. Each test site was treated with a particular
composition and challenged daily with irritant mixture for up to
ten days. When a test site reached a score of 2.5 or more, the test
site was no longer treated or challenged. Participants returned
daily (including weekends) for patch removal, evaluation and
subsequent composition/irritant mixture application.
[0214] The lower the score, the more effective a composition was at
preventing an irritation response. In Table 7. below, the
irritation scores for four different NARLEX DC-1 polymer test
compositions are provided for comparison with the scores for a
petrolatum control and an irritant control. The NARLEX DC-1 polymer
that was used contained 34% solids.
9TABLE 7 Number of 0.2% 1.7% 7.5% 16.8% Days After NARLEX NARLEX
NARLEX NARLEX Application DC-1 DC-1 DC-1 DC-1 of Irritant
Petrolatum Irritant polymer Test polymer Test polymer Test polymer
Test Mixture Control Site Control Site Composition Composition
Composition Composition 1 0.1 0.6 0.2# 0.2# 0.3# 0.9# 2 0.2 0.9 0.4
0.4 0.1 # 0.2# 3 0.5 1.2 0.6 0.7 0.3# 0.2# 4 0.6 1.7 1.0# 0.8#*
0.5# 0.6# 5 1.4 1.9 1.5# 1.3# 1.0# 1.4# 6 1.7 2.1 1.6# 1.6# 1.0#*
1.6# 7 2.0 2.0 1.5# 1.4# 1.2#* 1.7# 8 2.0 2.0 1.5# 1.6# 1.1#* 1.5#
9 1.8 2.3 1.6# 1.7# 1.2#* 1.5# 10 1.9 2.4 1.8# 1.7# 1.5#* 1.7#
[0215] An asterisk ("*") after a value indicates a significant
difference from the petrolatum control. A number sign ("#") after a
value indicates a significant difference from the irritant control
at a confidence level of 95%. The statistical analysis performed
factored in the number of participants at any given time during the
study. The number of participants varied between compositions
because participants were dropped if their erythema scores reached
the upper limit of 2.5. The irritation score results in Table 7.
show that each of the NARLEX DC-1 polymer test compositions reduced
skin irritation from day 1 of the study forward compared with the
irritant control. Therefore, the compositions of the invention
provide a benefit to skin that is exposed to biological insults
such as fecal proteases and bile-acids.
[0216] A second clinical study that was conducted also supports the
efficacy of the compositions of the invention for reducing the
irritation response of skin and for protecting the skin from
irritants. Twelve healthy Caucasian participants were recruited who
were between the ages of 18 and 60. Test areas were marked on the
upper backs of the study participants. This study involved topical
application of 30 I of test composition to the skin followed by
patching with a protease/bile acid mixture in a 2.5 cm diameter
HILLTOP chamber fitted with a pad. The proteases, trypsin and
chymotrypsin (available from Specialty Enzymes and Biochemicals Co.
of Chino, Calif.) were topically applied daily in the form of a
patch having a concentration of 1500 g/ml plus bile acids to
represent a repeated biological insult. The bile acid mixture
included 6 mg/ml cholic acid sodium, 6 mg/ml deoxycholic acid
sodium and 3 mg/ml chenodeoxycholic acid sodium, each in
phosphate-buffered saline (each acid is available from Sigma
Chemical Company of St. Louis, Mo.). The phosphate-buffered saline
had a pH of 7.4 (available from Life Technologies of Rockville,
Md.) and a control site to which only phosphate-buffered saline was
applied was also included in the study.
[0217] When the HILLTOP chambers containing the treated pads were
placed on the designated, randomized test sites on the upper backs
of the test participants, the chambers were covered with SCANPOR
semi-occlusive tape. The chambers remained in place overnight.
During each daily visit, the chambers were removed and the
underlying skin was allowed to air dry for 15-20 minutes. After the
drying period, each test and control site was visually assessed in
a blinded manner by an expert grader. The expert graders made the
visual assessments under consistent lighting and the graders used a
scoring system of 0 (no erythema) to 3 (severe erythema with edema
and vesicles). If a visual score of greater than or equal 2 was
observed for any test site, the site was no longer treated. Every
day, the chambers were re-loaded with 200 L of fresh solution. The
study was conducted for twelve days, Monday through Saturday (the
chambers remained in place from Saturday to Monday).
[0218] Each study participant had four test sites on their upper
back (including the saline and irritant controls): (1)
Phosphate-buffered saline (pH=7.4); (2) Irritant mixture of 1500
g/ml trypsin/chymotrypsin+bile acids; (3) Petrolatum "control"
(containing 98.17% petrolatum; 1.68% ABIL EM90 emulsifier; and
0.15% propylparaben); and (4) Petrolatum plus polymer (containing
82.17% petrolatum; 16% NARLEX DC-1; 1.68% ABIL EM90 emulsifier; and
0.15% propylparaben). The petrolatum used in compositions "3" and
"4" was sourced from Ultrapure Chemical, Inc.; the ABIL EM90
emulsifier was sourced from the Goldschmidt Chemical Company; and
the propylparaben was sourced from Protameen Chemicals. The
cumulative irritation scores are reported for each of the four
sites in Table 8. below. The cumulative irritation scores are based
on the highest erythema value obtained for a site; for example, if
a site reached a score of 2 and was discontinued, but had a score
of 3 on the following day, the score of 3 was used for the
cumulative calculation.
10 TABLE 8 Test Site Cumulative Irritation Score Phosphate-buffered
saline site 80 Irritant Mixture 216 Petrolatum + emulsifier 134
Petrolatum + polymer + emulsifier 102.5
[0219] Using the mean score values reported in Table 9. below, the
data was analyzed using ANOVA statistical analysis. The analysis
showed that the Petrolatum+polymer+emulsifier sites had
significantly lower erythema than the Irritant Mixture sites and
the Petrolatum+emulsifier sites. Therefore, these clinical study
results support the efficacy of the compositions of the inventions
for reducing the irritation response of the skin and for protecting
the skin from irritants.
11 TABLE 9 Test Site Mean Irritation Score Phosphate-buffered
saline site 0.67 Irritant Mixture 1.8 Petrolatum + emulsifier 1.1
Petrolatum + polymer + emulsifier 0.85
[0220] In order to demonstrate that compositions of the invention
do indeed transfer from the liner or other bodyfacing material of
an absorbent article, studies were conducted to quantify the amount
of composition transferred from the liner of a diaper to a TEGADERM
skin patch. The studies were conducted on infants wearing a "Size
3" HUGGIES diaper fitting a child ranging in weight from about 16
to about 28 pounds. The children participating in the studies wore
the test diapers for a period of 6 hours; therefore, the amount of
composition transferred to a TEGADERM skin patch over a period of 6
hours was measured. The children were first evaluated for any type
of diaper rash or skin irritation and, if such irritation was
present, those children did not participate. Prior to application
of the diapers being evaluated in the studies, each participating
child's buttocks were wiped with a HUGGIES NATURAL CARE unscented
wet wipe. A 1.75 square inch TEGADERM adhesive skin patch was then
applied to each participating child's buttocks in such a way that
the entire skin patch would be in contact with the bodyfacing
surface of the bodyside liner of the diaper. Next, a disposable
diaper having a composition of the invention on the bodyfacing
surface of the bodyside liner was applied to each child. The
children wore the test diapers for six hours, however, between the
three and 4 hour time points, the children's' caregivers changed
their diapers and applied a new test diaper. After six hours, the
diapers and the TEGADERM skin patches were removed. The TEGADERM
skin patches were removed by first lifting up one corner of the
patch and then gently pulling back the patch to remove. The skin
patches were placed in individual vials using tweezers to avoid
contamination. The skin patches were then analyzed for the amount
of composition taken up from the bodyside liners of the diapers.
The amount of composition taken up was determined by extracted the
composition from the skin patches and then quantifying the amount
using gravimetric analysis. Descriptions of the compositions tested
and the results of the transfer studies are reported below in Table
10.
12TABLE 10 Add-On Level of Average Amount of Composition to
Composition Diaper Composition Applied to Bodyside Liner
Transferred to Skin Relative Sample Bodyside Liner (grams/18" of
Patch Standard Number (amounts are % by weight) diaper length)
(mg/cm.sup.2) Deviation 1.sup.a Petrolatum, 42.2% 0.2 0.104 23%
Ozokerite Wax, 40% Soy Sterol 0.8% Sunflower Oil, 10% PROLIPID 141
blend, 1% Glycerin, 5% Sorbitan Monooleate, 0.85% Polysorbate 80,
0.15% 2.sup.b Petrolatum, 42.2% 0.2 0.105 18.3% Ozokerite Wax, 40%
Soy Sterol, 0.8% Sunflower Oil, 10% PROLIPID 141 blend, 1%
Glycerin, 5% Sorbitan Monooleate, 0.85% Polysorbate 80, 0.15%
3.sup.c Petrolatum, 60% 0.34 0.074 41.2% Ozokerite Wax, 40% 4.sup.c
Petrolatum, 42.2% 0.24 0.128 23.7% Ozokerite Wax, 40% Soy Sterol,
0.8% Sunflower Oil, 10% PROLIPID 141 blend, 1% Glycerin, 5%
Sorbitan Monooleate, 0.85% Polysorbate 80, 0.15% 5.sup.c
Petrolatum, 41% 0.24 0.084 48.9% Ozokerite Wax, 38.2% Soy Sterol,
0.80% Sunflower Oil, 10% PROLIPID 141 blend, 1% Glycerin, 5%
Sorbitan Monooleate, 0.85% Polysorbate 80, 0.15% Dimethicone, 2%
Alkyl Silicone Wax, 1% 6.sup.c Petrolatum, 42.2% 0.34 0.173 33.2%
Ozokerite Wax, 40% Soy Sterol, 0.8% Sunflower Oil, 10% PROLIPID 141
blend, 1% Glycerin, 5% Sorbitan Monooleate, 0.85% Polysorbate 80,
0.15% 7.sup.a Petrolatum, 42.2% 0.10 0.114 17.5% Ozokerite Wax, 40%
Soy Sterol, 0.8% Sunflower Oil, 10% PROLIPID 141 blend, 1%
Glycerin, 5% Sorbitan Monooleate, 0.85% Polysorbate 80, 0.15%
8.sup.e Petrolatum,41% 0.28 0.103 38.8% Ozokerite Wax, 38.2% Soy
Sterol, 0.80% Sunflower Oil, 10% PROLIPID 141 blend, 1% Glycerin,
5% Sorbitan Monooleate, 0.85% Polysorbate 80, 0.15% Dimethicone, 2%
Alkyl Silicone Wax, 1% 9.sup.d Petrolatum, 42.2% 0.20 0.246 16.7%
Ozokerite Wax, 40% Soy Sterol, 0.8% Sunflower Oil, 10% PROLIPID 141
blend, 1% Glycerin, 5% Sorbitan Monooleate, 0.85% Polysorbate 80,
0.15% 10.sup.e Petrolatum, 42.2% 0.18 0.258 10.0% Ozokerite Wax,
40% Soy Sterol, 0.8% Sunflower Oil, 10% PROLIPID 141 blend, 1%
Glycerin, 5% Sorbitan Monooleate, 0.85% Polysorbate 80, 0.15%
.sup.a= bodyside liner was a spunbond material and the composition
was applied by spray application .sup.b= bodyside liner was a dual
layer liner and the composition was applied by spray application
.sup.c= bodyside liner was a dual layer liner and composition was
applied by slot coating .sup.d= composition was applied in a
pinstripe pattern using a hybrid of spray application and slot
coating .sup.e= bodyside liner was a spunbond material and
composition was applied by slot coating
[0221] The average amount of composition transferred to the skin
patch is based on a sample size of twenty for each diaper sample.
The results in Table 10 show that the compositions of the invention
do indeed transfer from the bodyside liner of the diaper to the
skin of the wearer of the absorbent article. While the compositions
used in these transfer studies did not contain decoupling polymers,
it is expected that similar composition with decoupling polymers
would transfer to the skin similarly. The decoupling polymers are
not expected to impact transfer of the composition from the
bodyside liner to the skin.
[0222] The preceding test results representatively illustrate that
the compositions of the present invention protect the skin barrier
and subdue the inflammatory response of the skin when the skin is
exposed to biological insults. The compositions are efficacious
when applied to the skin directly and when transferred to the skin
from a liner material such as would be a component of an absorbent
article.
[0223] While the invention has been described in detail with
respect to the specific aspects thereof, it will be appreciated
that those skilled in the art, upon attaining an understanding of
the foregoing, may readily conceive of alterations to, variations
of, and equivalents to these aspects. Accordingly, the scope of the
present invention should be assessed as that of the appended claims
and any equivalents thereto.
* * * * *