U.S. patent application number 10/454814 was filed with the patent office on 2003-10-23 for impregnated matrix and method for making same.
This patent application is currently assigned to Unilever Home & Personal Care USA, Division of Conopco, Inc.. Invention is credited to Sheridan, Christopher H..
Application Number | 20030199838 10/454814 |
Document ID | / |
Family ID | 26867306 |
Filed Date | 2003-10-23 |
United States Patent
Application |
20030199838 |
Kind Code |
A1 |
Sheridan, Christopher H. |
October 23, 2003 |
Impregnated matrix and method for making same
Abstract
A substantially flexible, dry matrix, which contains not more
than about 3% moisture at room temperature, is impregnated with a
water free treatment mixture containing a lipid and a surfactant.
In a preferred embodiment, the mixture includes a glycol, a
surfactant and a lipid emollient, lubricant, medicament or skin
protectant. Methods for manufacturing and using the impregnated
matrices are also taught.
Inventors: |
Sheridan, Christopher H.;
(Cresskill, NJ) |
Correspondence
Address: |
UNILEVER
PATENT DEPARTMENT
45 RIVER ROAD
EDGEWATER
NJ
07020
US
|
Assignee: |
Unilever Home & Personal Care
USA, Division of Conopco, Inc.
|
Family ID: |
26867306 |
Appl. No.: |
10/454814 |
Filed: |
June 4, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10454814 |
Jun 4, 2003 |
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09998151 |
Nov 29, 2001 |
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09998151 |
Nov 29, 2001 |
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09613033 |
Jul 10, 2000 |
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09613033 |
Jul 10, 2000 |
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08868344 |
Jun 3, 1997 |
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6103644 |
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08868344 |
Jun 3, 1997 |
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08560035 |
Nov 17, 1995 |
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08560035 |
Nov 17, 1995 |
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08171676 |
Dec 22, 1993 |
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Current U.S.
Class: |
604/289 |
Current CPC
Class: |
A61Q 19/00 20130101;
Y10T 442/2262 20150401; A61K 8/0212 20130101; Y10T 442/2311
20150401; Y10T 442/2205 20150401; Y10T 442/674 20150401; Y10T
442/2098 20150401; Y10T 442/20 20150401; A61K 8/027 20130101; Y10T
442/2484 20150401; Y10T 442/2508 20150401; Y10T 442/2525 20150401;
Y10T 428/249962 20150401 |
Class at
Publication: |
604/289 |
International
Class: |
A61M 035/00 |
Claims
Therefore, I claim:
1. A dry matrix comprising a. a plurality of fibers; and b. a film
on at least part of said fibers, said film comprising: i. at least
one member selected from the group consisting of lipid emollients,
lubricants and protectants; and ii. a surfactant.
2. The dry matrix of claim 1, wherein said surfactant comprises a
glycol.
3. The dry matrix of claim 1, wherein said surfactant is a member
of the group consisting of cationic and anionic surfactants.
4. The dry matrix of claim 1, wherein said plurality of fibers have
regions with a hydrophobic character and regions with a hydrophilic
character.
5. The dry matrix of claim 1, wherein said surfactant comprises
between about 15%-50%, by weight, of said film.
6. The dry matrix of claim 1, wherein said film composition has a
viscosity, at 25.degree. C. of less than about 300 cps.
7. The dry matrix of claim 1, wherein said surfactant has a
hydrophilic-lipophilic balance between about 4 and 11.
8. The dry matrix of claim 1, wherein the only water present is
said dry matrix is bound to said plurality of fibers.
9. The dry matrix of claim 1 comprises substantially no added
water.
10. The dry matrix of claim 2 wherein said glycol is present in an
amount between about 1% and about 99% by weight of said film
composition.
11. The dry matrix of claim 2 wherein said glycol is selected from
the group consisting of propylene glycol, polyethylene glycol and
methoxy polyethylene glycol.
12. The dry matrix of claim 2 wherein said glycol is present in an
amount between about 4% and about 50% by weight of said film
composition.
13. The dry matrix of claim 1, wherein said emollient is selected
from the group consisting of stearyl ether, caproic esters and
lanolin.
14. The dry matrix of claim 13, wherein said emollient is present
in said film composition in an amount of up to about 50% by weight
of said film composition.
15. The dry matrix of claim 1, wherein said lubricant is a member
selected from the group consisting of mineral oil, petrolatum and
wax.
16. The dry matrix of claim 15, wherein said lubricant is present
in said film composition in an amount up to about 50% by weight of
said film composition.
17. The dry matrix of claim 1, wherein said protectant is selected
from the group consisting of dimethyl polysiloxane, cyclomethicone
and lanolin.
18. The dry matrix of claim 17, wherein said protectant is present
in the non-aqueous mixture in an amount up to about 50% by weight
of the non-aqueous mixture.
19. The dry matrix of claim 1, wherein said medicament is a member
selected from the group consisting of zinc oxide, aloe, titanium
dioxide, miconazole, bacitracin, neomycin, polymyxin, vitamins A,
D, and E, salicylic acid, retinoic acid, resorcinol, benadryl,
sulfadiazine, sulfaguanidine, citronellol and hydrocortisone, and
is present in an amount up to about 50% by weight.
20. A method of treating a skin surface comprising the steps of: a.
obtaining a dry matrix comprising i. a plurality of fibers; and ii.
a film on at least part of said fibers, said film comprising: a) at
least one member selected from the group consisting of lipid
emollients, lubricants and protectants; and b) a surfactant; and b.
rubbing said skin surface.
Description
[0001] This application is a continuation-in-part of co-pending
application Ser. No. 08/560035 filed ______, which in turn is a
continuation-in-part of application Ser. No. 171,676 filed Dec. 22,
1993.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a treated matrix and method
for making and using the same. More particularly, the present
invention relates to a matrix treated with at least one lipid,
emollients, lubricants, antimicrobial agents, skin protectants or
medicaments and a surfactant. This matrix transfers the lipid to a
skin surface as a thin film on contact.
[0004] 2. Description of the Art
[0005] Heretofore, emollients, protectants, medicaments and
lubricants that are slightly, or not, soluble in water have been
applied using emulsions of oil and water. Examples of such
emulsions include skin lotions and other skin care products.
However, such emulsions are non-uniform, separate, and are
susceptible to bacterial growth. While the addition of surfactants
improves and extends the life of emulsion,, such additions do not
solve the problems since oil and water simply do not mix. Moreover,
such compositions are difficult to formulate and apply.
[0006] U.S. Pat. No. 5,091,102, entitled Method of Making a Dry
Antimicrobial Fabric, issued to Sheridan, the applicant herein, on
Feb. 25, 1992, and was assigned to the same assigned as the present
application. This patent is directed to a method of making a
substantially flexible dry matrix or towel for use in cleaning a
surface by removing dust and/or organic film products. The Sheridan
U.S. Pat. No. 5,091,102 matrix includes a glycol compound, a
cationic surfactant, and antimicrobial agent and, in a preferred
form, a nonionic surfactant, each of which is water soluble.
[0007] As disclosed in Sheridan U.S. Pat. No. 5,091,102, in example
1 thereof, at col. 9 line 40-col. 10 line 23, commercially
available dust cloths cannot clean a surface because they are
incompatible with water and leave an oil-in-water smear behind.
Even when squeezed dry, they are oil and create more dirt to be
cleaned. The invention described in Sheridan U.S. Pat. No.
5,091,102 solved the problem by being able to clean with water.
Because the components are water soluble, they are able to clean
the surface with water. Sheridan's success was attributable to
restricting the cleaning components to water soluble materials.
[0008] Sheridan U.S. Pat. No. 5,091,102, however, did not address
the specific problem confronted herein, namely providing a vehicle
or matrix for transferring and emollient, lubricant, protectant,
and/or medicament where at least one of the components was water
insoluble as defined in the CRC Handbook of Chemistry and Physics,
i.e., an emollient, petrolatum, zinc oxide, vitamin A, vitamin D,
zinc carbonate, etc., or of low water solubility, i.e., slightly
soluble.sup.1 in water such as zinc citrate, zinc phenate,
sulfadiazole, sulfa-guanidine, citronellol, hydantoin, etc. As used
herein, the terms soluble and slightly soluble are used in the
conventional sense (see Hackh's Chemical Dictionary, for example).
This is particularly applicable to transferring a skin care product
to the skin from the matrix. .sup.1 Slightly soluble--soluble in
water on a relative scale: 1=insoluble, 2=slightly insoluble,
3=soluble, 4=very soluble, 5=miscible (CRC Handbook of Chemistry
and Physics, 75th Edition, David R. Gide, page 1-3).
Soluble--capable of mixing with a liquid (dissolving) to form a
homogeneous solution The degree of solubility may conventionally be
expressed: very soluble--less than 1 part solvent freely
soluble--from 1 to 10 parts solvent soluble--from 10 to 30 parts
solvent sparingly soluble--from 30 to 100 parts solvent slightly
soluble--from 100 to 1000 parts solvent very slightly soluble--from
1000 to 10,000 parts solvent insoluble--more than 10,000 parts
solvent needed to dissolve 1 part substance (solute). (Hackh's
Chemical Dictionary, 3d Edition, p.787.)
SUMMARY OF THE INVENTION
[0009] Against the foregoing background, it is a primary object of
the present invention to provide a dry matrix which is impregnated
with a mixture of at least one liquid surfactant and a lipid such
as an emollient, a lubricant, a medicament and/or a skin
protectant.sup.2. .sup.2 "[L]ipids are material which are soluble
in organic solvents and essentially insoluble in water." R. M.
Burton & F. C. Guerra, FUNDAMENTALS OF LIPID CHEMISTRY, 2
(1974).
[0010] It is another object of the present invention to provide a
method of making the impregnated matrix of the present
invention.
[0011] It is a further object of the present invention to provide a
substantially water-free treated matrix for shipping.
[0012] It is yet a further object of the present invention to
provide a treated matrix that does not require packaging effective
to prevent the evaporation of water or solvents.
[0013] It is yet another object of the present invention to provide
a treated matrix that is microbially stable, even when not packaged
within a moisture migration barrier.
[0014] It is a still further object of the present invention to
provide such a matrix which, when exposed to water and pressure,
will substantially instantaneously form an emulsion which can serve
to transfer the surfactant, the emollient, lubricant, medicament
and/or protectant from the matrix to a skin surface.
[0015] To accomplish these and other objects of the present
invention, the composition of the present invention comprises a
substantially flexible, dry matrix having a moisture content not
exceeding about 3%, impregnated with a water-free treatment
mixture. The matrix is adapted to transfer lipid components in said
treatment mixture to a skin surface on contact. The treatment
mixture preferably includes at least one liquid surfactant and at
least one lipid. The lipid is preferably selected from the group of
emollients, lubricants, medicaments and skin protectants. A method
for forming said impregnated matrix is further provided as is a
method for applying a lipid emollient, lubricant, medicament and/or
protectant mixture to skin.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The present invention relates to a substantially dry matrix
or matrix of the type which is described, for example, in U.S. Pat.
No. 5,091,102 the disclosure of which is hereby expressly
incorporated herein by reference thereto. Such matrix is
substantially dry and is devoid of any water other than the water
which may be naturally present in the matrix as manufactured and
the matrix remains dry to the touch after impregnation with the
treatment mixture. A typical matrix for use in the present
invention is a cellulosic material, which while dry to the touch,
may contain up to about 3% water.
[0017] As used herein, the term matrix may further include the
finished matrix, cloth or towel product, i.e., a wipe, garment,
etc.
[0018] A useful matrix may contain natural or synthetic fibers,
processed into woven, non-woven or knitted form, a flexible foam,
or combinations thereof, in a basis weight range generally of
between 5 and about 200 grams per square yard and preferably
between 15 and about 100 grams per square yard. A preferred matrix
is comprised of woven or non-woven thermoplastic filaments or
fibers, preferably of polypropylene, with a basis weight range of
between about 5 and about 100 grams per square yard, preferably
between 15 and 40 grams per square yard. The tensile strength of
such a matrix must be sufficient to enable the wipe to be used
without shredding or disintegrating and should generally be between
about 0.5 and about 1.5 pounds per inch of width. The matrix can
consist of a single layer of the filaments or fibers or a foam
layer or it can consist of a plurality of layers of the same
filaments or fibers and/or foam which have been adhered by using
any suitable method such as sonic, thermal or mechanical bonding,
etc. Final selection of the matrix will, of course, depend upon its
actual intended application.
[0019] Particularly preferred matrices include fibers selected from
the group consisting of polypropylene, polyester, nylon and
cellulosic, such as cellulose, cotton, rayon, hemp, etc. and foams
selected from the group consisting of polyurethane, polypropylene,
polyethylene, polyester, etc.
[0020] A treatment mixture preferably consists of at least one
surfactant and a lipid emollient, and/or protectant, and/or a
medicament, and/or lubricant. The treatment mixture is applied to
the matrix and impregnated therein. When the matrix is applied to
skin, the lipid is readily transferred thereto and remains on the
skin as a film. In another aspect of the present invention, when
the matrix is exposed to water at the point of use and pressure is
applied by squeezing, or rubbing, the matrix, the treatment mixture
forms an unstable emulsion which maybe adapted to release the lipid
onto the skin.
[0021] The treatment mixture preferably includes a glycol, and more
preferably propylene glycol, USP, although any glycol which is
safe, nontoxic and possesses the ability to coat fibers uniformly
may be used. The glycol used desirably imparts a softness to the
dry matrix. The glycol may act as a non-ionic liquid surfactant, or
in any other conventional capacity for which glycol is used in the
cosmetic and pharmaceutical industries.
[0022] Polyethylene glycol and CARBOWAX.RTM. (methoxy polyethylene
glycol), may also be used in the present invention. These compounds
are members of a family of linear polymers formed by the addition
reaction of ethylene oxide. The generalized formula for
polyethylene glycol is:
HO--(CH.sub.2CH.sub.2O).sub.n--H
[0023] and for the methoxy polyethylene glycol is:
CH.sub.3O--(CH.sub.2CH.sub.2O).sub.n--H
[0024] wherein "n" is the average number of repeating oxyethylene
groups. The repeating ether linkages and terminal hydroxyl groups
give rise to the water solubility of the polyethylene glycol.
[0025] Polyethylene glycol is generally available in average
molecular weights ranging from 200 to 8000 and methoxy polyethylene
glycol is available is average molecular weights ranging from 300
to 5000.
[0026] The treatment mixture typically contains a glycol in an
amount between 1% and about 99% by weight of the treatment mixture
and, preferably, between about 4% and about 50% by weight.
[0027] The treatment mixture optionally also contains other
nonionic and cationic surfactants, either separately or in
combination. The cationic and nonionic surfactants described in
U.S. Pat. No. 5,091,102, the disclosure of which is hereby
incorporated herein by reference, may be used in the present
invention. Preferred cationic surfactants can be selected from any
of the well-known classes of water soluble quaternary ammonium
compounds. Such classes include the quaternary heteronium.sup.3
compounds such as cetyl pyridinum chloride and polymeric quaternary
compounds of the general formula: 1The term "heteronium compound"
is defined in Hackh's Chemical Dictionary, 4th Edition, as a
"hetero--prefix (Greek) indicating unlikeness or difference" and
"onium--suffix and indicating a complex cation . . . "
[0028] wherein R.sub.1 and R.sub.2 are selected from an alkyl
group, an alkyl ether group and a hydroxyalkyl group each
containing from 1 to 3 carbon atoms. R.sub.3 is an alkyl group
containing from 6 to 20 carbon atoms, and R.sub.4 is selected from
an alkyl group containing 6 to 20 carbon atoms, an aralkyl group
wherein alkyl contains 1 to 2 carbon atoms and heterocyclic
radicals and X.sup.- is a suitable anion such as halide, e.g.,
chloride, bromide and iodide or nitrate, methosulfate or
acetate.
[0029] A particularly useful compound having the general formula
listed above is one wherein R and R.sub.1 and R.sub.2 are alkyl
groups having 1-3 carbon atoms, R.sub.3 is an alkyl benzyl group
such as dodecylbenzyl, R.sub.4 is a polypropylene oxide group, and
X is chloride.
[0030] Particularly useful quaternary ammonium compounds of the
above-indicated generated formula are the C.sub.8-18 alkyl dimethyl
ammonium chlorides and mixtures thereof.
[0031] Examples of such cationic surfactants which may be used
include: Stepan BTC 2125M or BTC 65.
[0032] The preferred amount of cationic surfactants compound to be
included in the treatment mixture in accordance with the present
invention ranges between about 0.5% and about 50% by weight, and
preferably is between about 1% and about 25% by weight.
[0033] The preferred glycol compounds themselves exhibit nonionic
surfactant properties. In addition, however, depending upon the
specific end use to which the matrix is to be put, the mixture may
also be optionally contain up to about 0.5% to 50% by weight of
another nonionic surfactant in addition to the glycol specified
herein. Suitable nonionic surfactants include those selected from
the group consisting of:
[0034] (a) the polyethylene oxide condensates of alkyl and dialkyl
phenols, having a straight or branched alkyl group of from about 6
to about 12 carbon atoms with ethylene oxide, wherein the amount of
ethylene oxide present is from about 3 to about 25 moles per mole
of alkyl phenol;
[0035] (b) the condensation products of aliphatic alcohols with
ethylene oxide of the formula RO (C.sub.2H4O).sub.n H and/or
propylene oxide of the formula RO(C.sub.3H.sub.6O).sub.nH: wherein
in either or both cases R is a straight or branched alkyl group
having from about 8 to 22 carbon atoms, and n is 3 to 40;
[0036] (c) polyoxyethylene polyoxypropyl block polymers.
[0037] When employed in accordance with the present invention, the
nonionic surfactant may be present in the treatment mixture in an
amount up to about 50% by weight of the treatment mixture and,
preferably, in an amount between 0.5 to 50% and most preferably
about 5% and about 40% by weight of the total mixture.
[0038] The surfactant composition used in the dry matrix of the
present invention may alternatively comprise a non-ionic and an
anionic surfactant.
[0039] It is also desired that the surfactant composition used in
the dry matrix of the present invention has a
hydrophilic-lipophilic balance between about 4 and 11.
[0040] As previously stated, the treatment mixture further contains
a lipid which can be one or more members of the group of
emollients, lubricants, surface protectants, and medicaments for
transfer to the skin surface.
[0041] Useful emollients include stearyl ethers and caproic esters.
Emollients serve to soften skin. A particularly preferred emollient
is a caprylic/caproic ester, most preferably the product sold by
HULS America under the trademark MYGLIOL 812.sup.4 .sup.4insoluble
in water.
[0042] The emollient should be included in the treatment mixture in
an amount between about 5% and about 70% by weight of the treatment
mixture, and preferably, in an amount between about 20% and about
40%.
[0043] Useful lubricants include mineral oil.sup.5 petrolatum.sup.6
and wax.sup.7. Lubricants serve to protect skin and prevent
moisture loss. They also function as humectants. A particularly
preferred lubricant is mineral oil and, most preferably, the
mineral oil product sold by J. T. Baker under the trademark Mineral
Oil USP. The lubricant may be included in the treatment mixture in
an amount between about 1% and about 50% by weight of the treatment
mixture and, preferably, in an amount between about 1% and about
15%. .sup.5 Insoluble in water. .sup.6 Insoluble in water. .sup.7
Insoluble in water.
[0044] Useful protectants include the polysiloxanes.sup.8,
dimethicone.sup.9 and cyclomethicone.sup.10. A particularly
preferred protectant is dimethyl polysiloxane, and most preferably,
the silicone product sold by General Electric, under the trademark
Silicone Fluid SF96-350. .sup.8 Insoluble in water. .sup.9
Immiscible in water. .sup.10 Immiscible in water.
[0045] The protectant, when so included, should comprise between
about 5% and about 50% by weight of the treatment mixture and,
preferably, be present in an amount between about 10% and about
25%. It will be appreciated, however, that the actual amount of
protectant will vary depending upon the particular protectant and
the application.
[0046] In a similar manner, medicaments such as, for example, zinc
oxide.sup.11, aloe, titanium dioxide.sup.12, sulfadiazine.sup.13,
sulfaguanidine.sup.14, citronellol.sup.15 and the like can also be
included for application to the skin surface. Other pharmacological
agents that could be included would be (a) vitamins A, C, D,
E.sup.16 etc. (b) antimicrobials such as bacitracin, neomycin,
miconazole, oxyquinoline, polymycin, and the like, (c)
anti-inflammatory agents such as steroids, (d) antihistamine agents
such as benadryl, (e) anti-acne agents such as salicylic acid or
retinoic acid.sup.17 etc. .sup.11 Insoluble in water. .sup.12
Insoluble in water. .sup.13 Sparingly soluble in water. .sup.14
Sparingly soluble in water. .sup.15 Very slightly soluble in water.
.sup.16 Insoluble in water. .sup.17 Insoluble in water.
[0047] It will of course be appreciated that the treatment mixture
may contain the lipid emollients, lubricants, protectants, and
medicaments, either singularly or in combination, depending upon
the particular application.
[0048] In order to prepare an impregnated matrix, a treatment
preparation is made by strongly agitating the components. This
preparation is added to the matrix.
[0049] The matrix may be prepared in the manner described in U.S.
Pat. No. 5,091,102. Commercially manufactured matrices may also be
used such as, for example, DuPont's Sontara matrix which consists
of a mixture of cellulosic and synthetic fibers normally supplied
in a basis weight of 62 grams per square yard.
[0050] The matrix is then coated with the treatment mixture using a
conventional transfer process such as, for example, the process
described U.S. Pat. No. 5,091,102. In such a process, continuous
rolls of the matrix are passed between an engraved roller and a
smooth roller under pressure. The engraved roller includes a
plurality of cells and cavities that are defined by specific shape
and dimensions. During operation, the engraved roller is partially
submerged in the treatment mixture and rotates there through
causing the mixture to fill the cavities of the engraved portions
of the engraved roller. Excess mixture which may accumulate is
removed by a doctor blade. The mixture remaining in the cells of
the engraved roller is transferred by way of pressure absorption
and surface tension into the matrix as it passes under pressure
between the engraved roller and smooth roller. It will, of course,
be appreciated that the treatment mixture may also be applied to
the matrix by other treatment methods such as spraying, dipping,
extrusion or reverse rolls.
[0051] The treated matrix containing the predetermined measured
volume of treatment mixture may be wound onto rolls and/or is
converted into the desired product.
[0052] The "water-free" treated matrix is dry to touch on
fabrication, no separate drying step being required to dry the
same.
[0053] The impregnated or treated matrix may then be used for
direct application of the emollient, lubricant, medicament and/or
surface protection to the skin. When such matrix is placed in
contact with the skin, the lipid is transferred out of the matrix
and onto the skin in the form of a thin film. Furthermore, when the
treated matrix is exposed to water it the point of use and
sufficiently squeezed, or rubbed, the glycol, surfactants and
emollient, protectant, medicament and/or lubricant substantially
instantaneously form an emulsion with the water, which can transfer
the lipid to the skin surface.
[0054] It will be appreciated that the treated or impregnated
matrix containing non-aqueous components can be composed of one
layer or multiple layers.
[0055] When the matrix or wipe of the present invention is first
treated with the mixture of partially water and oil soluble
surfactants and emollients, antimicrobial agents, lubricants and/or
medicaments, at least one of which is a lipid, the lipid material
is believed to be absorbed on the lipophillic portion of the fibers
composing the matrix and spreads to form a thin film. When the
treated wipe is contacted with water at the point of use, the
aqueous phase is also absorbed by the hydrophilic portion of the
fibers and spreads to form a thin film. However, the emulsion does
not form (to any substantial degree) until (shear) energy (rubbing)
is applied to mix the matrix surfaces. The two immiscible phases
are both present absorbed on the surfaces of the fibers as high
surface area films in close contact. Rubbing the matrix or treated
wipe on skin, creates sufficient shear energy to overcome the
viscous resistance of the liquids and disperses the oil phase in
the aqueous phase creating an instant emulsion. The emulsion
transports the lipid material to the skin surface. Once the
shearing action stops, the emulsion breaks and the phases once
again separate on the matrix fiber. The emulsion reforms when
energy, i.e. rubbing, resumes. It should be noted that without the
emulsion, the lipid remains on the matrix.
[0056] In an alternative application of the treated matrix of the
present invention, the matrix is moistened and rubbed just before
use to form an unstable emulsion that is effective to transfer a
lipid to a skin surface when the skin is wet.
[0057] An emulsion is a dispersion of a first liquid in a second
immiscible liquid. Since most emulsions contain water as one of the
two phases, emulsions are usually classified as either an
oil-in-water (O/W) emulsion having droplets of oil dispersed in a
continuous water phase, or a water-in-oil (W/O) emulsion having
droplets of water dispersed in a continuous oil phase. The
continuous liquid, or phase, is referred to as the dispersion
medium, and the discontinuous liquid, or phase, is the disperse
phase.
[0058] One cannot prepare a stable emulsion of two pure immiscible
liquids. Rather, an emulsion requires a third component: an
emulsifying agent or surfactant. Generally, adding a surfactant
lowers the interfacial tension of the two phases which allows an
emulsion to form when the two immiscible liquids are mechanically
agitated. During agitation, both liquids form droplets with one of
the liquids becoming continuous and the other remaining in droplet
form when an emulsifier (a stabilizing compound) is included in the
agitated mixture. However, if this mixture of droplets does not
include the emulsifier, the droplets will separate into two phases
when the agitation ceases.
[0059] The type of emulsion, O/W or W/O, is determined in part by
the volume ratio of the two liquids, provided the ratio is
sufficiently high. For example with a 5% water and 95% oil volume
present (an oil to water phase ratio of 19), the emulsion will be a
W/O type. For moderate ratios (between about 0.3 and 3), the type
of emulsion is determined by several such as the order of addition
and the type of emulsifier. One liquid slowly added to the other
with agitation usually results in the last added phase being the
continuous one. However, the phase in which the emulsifier is most
soluble is generally the continuous phase. For example, water
soluble soaps stabilize oil-in-water emulsions whereas water
insoluble soaps stabilize water-in-oil emulsions.
[0060] Emulsification creates new surfaces between the two phases,
namely the surfaces between the droplets. Such surface creating
processes require energy: the surface free energy. Numerically, the
surface free energy is identical to the surface tension. However,
most of the energy consumed during emulsification is used to
overcome the viscous resistance of the liquids during agitation,
and not to enlarge the interface. As a consequence, low viscosity
liquids are easier to emulsify than high viscosity fluids. Based on
this observation, it is preferred that the viscosity at 25.degree.
C. of the lipid material used in the present invention is less than
about 300 cps.
[0061] Through the use of agitation or shear forces, emulsification
usually breaks the original phases into progressively smaller
droplets. Variations in the mode of agitation, the nature and
amount of emulsifying agent, pH and temperature changes also affect
emulsification.
[0062] Commercial applications usually require emulsions to be
stable for months, if not longer. But, how stability is defined,
and how it is measured, depends upon the specific application.
Nonetheless, when an emulsion breaks down, the dispersed droplets
coalescence, or flocculate. During flocculation, droplets combine
into large droplets until finally the droplets achieve an
observable separate phase. A fully separated emulsion consists of
separate oil and water layers.
[0063] Both the charge at the interface and the packing of the
emulsifier molecules effect the stability of an emulsion. Emulsions
with a small average droplet size are more stable. For this reason,
commercial emulsions are often prepared with homogenizers that
rapidly reduce droplet sizes.
[0064] While a low viscosity makes emulsification easier, a high
viscosity retards flocculation, and thus improves the emulsion's
stability.
[0065] The treated matrix of this invention is impregnated with a
mixture of a liquid surfactant and a lipid, which preferredly is a
skin protectant, antimicrobial agent and/or emollient.
[0066] In an alternative embodiment, directly before use, at least
about three parts, by volume, of water is added to each part, by
volume of the treated matrix. The towel is then rubbed on skin.
This rubbing provides sufficient shear and agitation to uniformly
disperse the lipid phase in the water phase which facilitates the
transfer of the active ingredients to the skin surface. To achieve
this instant emulsion under low shear conditions of the type
encountered when the skin is rubbed with a wipe, sufficient
surfactant that is partial solubility in both phases must be
present to reduce the interfacial tension and facilitate the
substantially instantaneous formation of the emulsion. In addition,
the viscosity of the dispersed and continuous phase are desirably
kept low by using a lipid with a low viscosity. Such lipids readily
emulsify upon application of "rubbing" shear. While this emulsion
breaks when the matrix is quiescent (i.e., when the rubbing stops),
it reforms with further rubbing.
[0067] To achieve the instant emulsion under low shear of this
invention, the surfactants are desirably present in an amount of at
least about 15% by weight of the lipids, and preferredly between
about 15 and 50% by weight. These surfactants also should exhibit
partial solubility in both the continuous phase (here, water) and
dispersed phase (here, lipid) so that the interfacial tension is
quickly reduced.
[0068] Unlike pre-prepared stable emulsions encountered in
commercial products heretofore, the stability of this in situ
formed emulsion once the rubbing (aggitation) stops is not
importent. In a preferred embodiment of the present invention, the
uniformly dispersed emulsion only exists while the matrix is being
agitated. i.e., rubbed. Nonetheless, this short lived emulsion is
effective to transfer the disperse phase from the matrix to the
rubbed skin surface.
[0069] Ordinarily, the low shear created by rubbing a treated wipe
on a skin surface insufficient to emulsify two immiscible liquids,
particularly when the two insoluble liquids are in a test tube or
mixing tank. The success of this invention is based on the
substantially instantaneous creation of the emulsion on the fibers
of the treated matrix. There, the two liquid phases exist as thin
films coating the matrix fiber surface, which results in a high
surface area films. In the presence of surfactants, these high
surface area thin films mix intimately and emulsify under low
shear.
[0070] The invention will be illustrated by the following examples
which are not to be construed in limitation thereof:
EXAMPLE I
Emollient
[0071] A matrix, composed of air laid cellulose and acrylic binders
weighing approximately 60 grams per yard square was treated with a
non aqueous mixture of lipid emollients and surfactants as set
forth below.
[0072] The matrix is suitable for use as a moistened baby wipe. The
treatment mixture described below was added to the matrix by using
a gravure printing mechanism, the gravure pattern roll of which
contains a uniform geometric cellular structure and turns within a
reservoir of treatment mixture. Any excess mixture being removed by
intimate contact with a doctor blade, transferring the treatment
mixture from its cellular structure to said matrix as the matrix
passes over the gravure roll while under pressure exerted upon the
matrix by a smooth roll parallel to, and above, the gravure
roll.
[0073] The treatment mixture was added to the matrix in an amount
of 10% of the weight of the matrix. Rolls of water-free treated
matrix, which are dry to the touch, were converted into 7".times.8"
"Z" folded, tab connected towels.
[0074] Stacks of these treated towels containing 80 folded
tab-connected sheets, were placed in a dispensing container.
Individual towels made from the water-free treated matrix were
applied directly to the skin. This application left a thin film of
the treatment mixture on the skin which softened the skin
appreciably. These same towels, when contacted with wet skin,
created an unstable emulsion, which allowed for both cleansing and
softening of the skin.
[0075] In one trial, an amount of water equal to three times the
weight of the towel stack was added at one time and the wetted
towels dispensed through an opening provided in the container. The
towels functioned as well as a standard Scott brand Baby Fresh
Moist Towel as a cleaner. The unique difference however, is that in
addition to cleaning skin, the towel of the present invention
transferred the emollients to the skin. Panels of adults who used
the towels of the present invention could discern the added
emollience.
1 CHEMICAL COMPONENT TRADE NAME AMOUNT Caprylic/ Miglyol 812 30.00
Caproic Ester Poly Oxypropylene 15 Stearyl Ether Arlamot-E 41.00
Polysorbate 85 Tween 18.10 Propylene Glycol USP 4.80 Benzalkonium
Chloride BTC-6 4.80 Dowcil 200 0.30 Fragrance 1.00 100.00
EXAMPLE II
Lubricant
[0076] Example I shows that a lipid emollient can be placed
uniformly on the skin by contact using a water free towel or a
moistened towel with pressure to create an unstable emulsion. This
example shows that a lipid lubricant can be applied in a similar
manner.
[0077] A polyethylene and/or polypropylene fiber matrix having a
basis weight of approximately 20 grams per square yard was treated
with the following formula at the rate of 100% of basis weight
yielding an add on of mineral oil (a lubricant) at 9-10%. At this
level of treatment, the matrix was noticeably "soft".
[0078] The water-free treatment mixture was applied to the matrix
in the same manner as described in Example I.
[0079] Individual towels made from the water-free treated matrix
were applied to skin by contact. This contact transferred a thin
film of the mixture to the skin. The skin felt noticeably
lubricious. These same towels, when contacted with wet skin,
created an unstable emulsion that also transferred the lubricant to
the skin.
2 CHEMICAL COMPONENT TRADE NAME AMOUNT Propylene Glycol USP 39.50
Polyethylene Glycol PEG 600 13.15 Plurafac-Alcohol Alkoxylate D-25
7.71 Plurafac-Alcohol Alkoxylate B-25-5 7.71 Alcohol Ethoxylate
Genopal 261.60 12.60 Mineral Oil 9.13 Benzalkonium Chloride BTC-6
10.00 Fragrance 0.20 100.00
EXAMPLE III
Medicament
[0080] A matrix consisting of 100% synthetic fiber thermally bonded
to itself and weighing approximately 20-28 grams per square yard
was treated with the water-free formulation listed below. A matrix
treated with only 1 time its weight of formulation was also
evaluated by placing the water-free treated matrix in water and
transferring the medicament from the matrix into the water.
[0081] The treatment preparation was applied as described in
Example I and weighed up to four times the basis weight of the
matrix.
[0082] An individual towel made using the water-free matrix was
applied to the skin by contact which transferred a thin film of the
mixture to the skin. Those same towels, when applied to wet skin
with pressure, created an unstable emulsion which aided the
transfer of the medicament to the skin under those conditions.
3 CHEMICAL COMPONENT TRADE NAME AMOUNT Propylene Glycol USP 50.00
Miconazolc Nitrate 45.00 Benzalkonium Chloride BTC 65 5.00
100.00
EXAMPLE IV
[0083] By using an oil based insect repellent such as citronellol
in the treatment mixture, a water-free treated matrix can be
prepared which transfers the insect repellent to the skin on
contact. In the presence of perspiration or water accompanied by
pressure, the towels of this example form am unstable emulsion that
evenly transfers the insect repellent to the skin.
EXAMPLE V
[0084] An air laid cellulose pulp and acrylic binders matrix
weighing 60 grams per square yard was treated with a substantially
water-free mixture of surfactants, emollients, skin protectants,
preservative, fragrance and propylene glycol as listed below:
4 Chemical Function wt. % Coconut oil Emollient 43.32 Polysorbate
Surfactant 10.33 Poly oxyproplylene Surfactant 10.33 stearyl ether
Propylene glycol Emollient 7.22 Dimethicone Skin Protectant 27.00
Isothiazoline Preservative 0.80 Floragreen Fragrance 1.00
100.00
[0085] The substantially water-free mixture was applied to the
matrix with a gravure pattern roll so that the add on to the air
laid pulp matrix was 18%. The water-free treated matrix was dry to
the touch and did not feel greasy. The water-free treated matrix
was analyzed for weight percent Dimethicone and found to contain
4.1% which corresponds with the theoretical amount predicted on the
matrix. The water-free treated matrix was carefully placed in water
so that it absorbed three times its dry weight in water. When
carefully squeezed only water was expressed from the wetted wipe
demonstrating that no emulsion had formed.
[0086] Another similarly treated wipe was rubbed together for 10
seconds and then squeezed. An unstable emulsion was expressed from
the wipe which separated into phase layers within a few seconds.
The expressed liquid was analyzed for Dimethicone and 1.2% was
found. This experiment demonstrated that the Dimethicone oil was
temporarily emulsified into the aqueous phase and was transferable
from the matrix via the dispersion medium.
EXAMPLE VI
[0087] A sonically bonded matrix of 2.2 oz/sq. yd consisting of a
top and bottom layer of 0.50 oz/sq. yd spun bonded polypropylene
and three inner layers of tissue was treated with the following
non-aqueous formulation.
5 Compound Function Wt. % (paper/cellulose) Propylene glycol
Emollient 25.0 Polyethylene glycol 600 Emollient 10.0 Mineral oil
Lubricant 25.0 Ethoxylated fatty alcohol Surfactant 30.0 Quaternary
fatty amine Preservative 10.0 100.0
[0088] The substantially water-free mixture was applied to the
matrix with a gravure pattern roll so that the add on to the
sonically bonded matrix was 22%. The water-free treated matrix felt
dry to the touch and when rubbed on skin, no oil feel could be
detected, but the skin surface repelled water. A 10 inch square of
water-free treated matrix was wetted with four times its weight in
water. When gently squeezed, only water was expressed from the
wipe.
[0089] Another treated wipe was wetted with substantially the same
weight of water and rubbed for several seconds on the surface of a
forearm. An oily residue was left on the forearm demonstrating that
under the influence of pressure from rubbing the treated wipe on
skin in the presence of water, an unstable emulsion formed.
* * * * *