WATER SOLUBLE SHEET COMPOSITION
FIELD OF THE INVENTION
The present invention relates to a composition in the form of a soluble sheet
which has a variety of uses, particularly in the personal care field.
BACKGROUND OF THE INVENTION
The prior art discloses various uses for soluble films. For instance, soluble
films have been used to enclose materials. U.S. Patent No. 5,385,737 to Shigeno,
et al. and Patent No. 4,544,693 to Surgant disclose soluble capsules into which
various substances can be placed.
Soluble films have also been used for cosmetic purposes. For example, U.S.
Patent No. 6,060,547 to Canter et al. discloses a water-in-oil emulsion film used to
form a makeup foundation. Another cosmetic application of water soluble films is
found in U.S. Patent No. 4,126,142 to Saute, which discloses a face mask which is
applied to the skin, allowed to dry, and then removed.
U.S. Patent No. 5,948,430 to Zerbe, et al, discloses a soluble film for oral
administration. The film is used for the delivery of materials via the mucous
membranes, particularly the buccal mucosa.
Although means for forming films for various applications are known in the
art, there is a need for a water soluble film which will bind surfactant and other
ingredients, and which, when exposed to water, will dissolve and provide personal
cleansing such as can be obtained from, for example, hand soap or body wash.
There is also a need for a water soluble film to which skin care ingredients may be
added and which will release such skin ingredients upon exposure to sufficient
moisture.
SUMMARY OF THE INVENTION
The present invention is a composition in the form of a soluble sheet or film
which has a variety of uses, particularly in the personal care field. Such sheets are
preferably water soluble, which aids in their use in the personal care field. The
water soluble sheets of this invention will bind surfactant and other ingredients, and
which, when exposed to water, will dissolve and provide personal cleansing such
as can be obtained from, for example, a soap bar or a liquid body wash.
An important component of these water soluble sheets is a so-called "base
composition," which includes a water soluble film forming polymer, a polyvinyl
alcohol, and a humectant such as propylene glycol. Surfactant may be added to the
liquid base composition so that, when the composition is dried into sheet form, the
sheet will generate foam when exposed to water and have cleansing properties. At
this stage, skin care ingredients may also be added to the base composition in
addition to or in place of the surfactant. Moreover, volatile alcohols or
hydrocarbons may also be incorporated into the liquid base composition to facilitate
drying of the composition to form the flexible sheet product.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a water soluble sheet product formed from
a novel base composition. Even without the addition of other ingredients, the base
composition, if allowed to dry, will form a water soluble sheet. As used herein, all
weights given represent the weight of the material in a 100% active form in the
composition.
The base composition includes from about 0.75% to about 5% by weight of
a water soluble polymer, from about 6.5% to about 23% by weight of polyvinyl
alcohol, and from about 0.75% to about 12% be weight of a humectant, with the
preferred humectant being propylene glycol. The remainder of the base
composition is water. Up to about 2% by weight of magnesium aluminum silicate
may also be added to the base composition to enhance its slip characteristics.
However, magnesium aluminum silicate results in a more viscous base composition,
which, in turn, effects the thickness of the resulting soluble sheet product.
The preferred water soluble polymer is polyvinylpyrrolidone (PVP), and the
most preferred PVP is 2-pyrrolidone, 1-ethenyl-homopolymer having an average
molecular weight of about 60,000 Daltons. Such PVP is available as PVP K-30
from International Speciality Products, in Wayne, New Jersey. Although it has been
discovered that PVP is the water soluble polymer which works best in the base
composition of the present invention, other water soluble polymers may be used in
place of or in combination with PVP. These water soluble polymers include
polyquaternium 10, magnesium aluminum silicate, VP/VA copolymer, ethyl ester
of PVM/MA copolymer, and sodium magnesium silicate. A suitable
polyquaternium 10 is available as Celquat CS 230M from National Starch in
Bridgewater, New Jersey. A suitable VP/VA copolymer is available as PVA 735
from International Specialty Products in Wayne, New Jersey. A suitable ethyl ester
of PVM/MA is available as Omnirez 2000 from International Specialty Products in
Wayne, New Jersey. An acceptable sodium magnesium silicate is available as
Veegum K from R.T. Vanderbilt in Norwalk, Connecticut. The level of water
soluble polymer or combination of water soluble polymers used in the base
composition should range from about 0.75% to about 5% by weight.
In the present invention, the polyvinyl alcohol functions as a film former, and
it is used in conjunction with the water soluble polymer. In the preferred
embodiment of the invention, the polyvinyl alcohol used has a hydrolysis of
between about 87% and 90%. A suitable polyvinyl alcohol having the preferred
hydrolysis range is available as AirVol polyvinyl alcohol supplied by Air Products
and Chemicals, Inc. in Allentown, Pennsylvania. Either AirVol 540, having a
hydrolysis of between about 87% and 89%, or AirVol 523 S, having a hydrolysis of
between about 87% and 90%> is preferred. In the most preferred embodiment of the
invention, AirVol 523 S is used because it best enhances the solubility of the soluble
sheet product. It has been found that a polyvinyl alcohol having a hydrolysis below
87%o results in a sheet which is less soluble. Above 90%, the sheet again loses
some solubility.
The preferred humectant is propylene glycol, which serves to aid the sheet
product to absorb water. In addition to propylene glycol, other humectants which
can be used as the humectant in the base composition of the present invention
include: (1) glycerin; (2) dipropylene glycol; (3) glyceryl polymethracrylate; and
(4) glyceryl polymethracrylate in combination with propylene glycol. The level of
humectant used in the base composition is normally from about 0.75% to about 12%
by weight. However, additional humectant can be added depending upon the end
use and desired characteristics of the soluble sheet. However, the amount of
humectant added should not adversely effect the formation of the soluble sheet
product.
In the preferred embodiment of the base composition, from about 1.5% to
about 2.5%o by weight of PVP, from about 13.5% to about 14.5% by weight of
polyvinyl alcohol, and from about 2.5% to about 3.5% of propylene glycol are used.
In the most preferred embodiment, about 1.75% of a PVP having an average
molecular weight of about 60,000 Daltons, about 13.91% of polyvinyl alcohol
having a hydrolysis between about 89% and 90%), and about 2.94%» of propylene
glycol are used. The balance of the base composition is water.
In preparing the base composition of this invention, the water soluble
polymer and water are placed into a heatable container. With constant agitation,
polyvinyl alcohol is then slowly added to the water and water soluble polymer
mixture. When the polyvinyl alcohol has become saturated (starts to swell), heat is
applied until the mixture reaches about 180 °F . The mixture is agitated throughout
the heating process. Once the mixture has reached 180 °F, heating is discontinued.
At this point, the humectant is added. Preferably, agitation is continued until the
mixture has cooled to about 120 °F, although additives and water my be added to
the base composition while it is still hot. The base composition can be stored in a
tightly covered container. If it is to be stored for a long period of time prior to its
use for formation of the sheet product, a preservative such as DMDM hydantion
may be added. A suitable DMDM hydantion is available as Mackstat DM from
Mclntyre in University Park, Illinois.
In accordance with the present invention, various ingredients may be
combined with the base composition depending upon the intended use of the final
product. As used herein, the combination of base composition and surfactant and/or
other ingredients is referred to as the liquid product composition. I have found that
the base composition is compatible with a rather wide variety of surfactants,
emollients, humectants, beads, exfoliating agents, colorants and fragrance additives.
Once the desired ingredients have been combined with such the base composition,
the resulting liquid product composition is then dried to form the water soluble
sheet product. When the base composition is combined with such other ingredients,
the level of PVP, polyvinyl alcohol, and propylene glycol in the liquid product
composition should be as follows: about 0.15% to about 0.35 % by weight of PVP;
about 1.3% to about 2.78% by weight of polyvinyl alcohol; and about 0.15% to
about 0.59% by weight of propylene glycol. In general, a liquid product
composition useful for skin conditioning can include up to about 50% by weight of
skin feel ingredients, about 15% to about 90% by weight of the base composition,
with the balance of the liquid product composition being water. Although up to
about 50%) by weight of the liquid product composition may be skin feel
ingredients, depending upon the chosen skin feel ingredient, less than 50% by
weight of the liquid product composition should be used if formation of the soluble
sheet product is adversely effected.
In general, when surfactant is added to the base composition, a composition
useful for personal cleansing should include about 15% to about 90%» by weight of
the base composition, and to up to about 65% by weight of surfactant. As is
discussed in more detail below, water soluble soaps, anionic surfactants, nonionic
surfactants, cationic surfactants, and surfactant blends may all be added to the base
composition. The combined weight of surfactant should not exceed about 65% by
weight of the liquid product composition; however, the amount of surfactant which
can be added without adversely effecting the formation of the soluble sheet product
depends upon the chosen surfactant.
When the base composition is blended with selected ingredients, it is
preferred that the combination of the base composition and such ingredients include
about 20% by weight of base composition. However, the amount of base
composition used will vary depending upon the desired viscosity of the liquid
product composition and the corresponding desired thickness of the soluble sheet
product. In general, the more viscous the liquid product composition is, the thicker
the soluble sheet product formed from the liquid product composition will be. The
amount of surfactant added will vary depending upon the particular surfactant
chosen and the effect desired by the user. The addition of water is not required for
blending the base composition with a surfactant, but the change in the viscosity of
the base composition and surfactant mixture caused by the addition of water will
assist in the dispersal of additive components. Dilution with water will also reduce
product cost and produce thinner sheets.
In connection with the disclosure of surfactants, soaps, skin feel ingredients
and other ingredients, various exemplary formulations are given. These examples
are illustrative only, and they are not intended and do not limit the invention in any
way.
Anionic surfactants are the preferred surfactants for use with the base
composition of the present invention. Anionic surfactants which are compatible
with the base composition include ammonium laureth sulfate, sodium laureth
sulfate, and TEA-cocoyl glutamate. A suitable ammonium laureth sulfate is
available as Standapol A from Cognis in Ambler, Pennsylvania. Sodium laureth
sulfate is also available from Cognis as Standapol ES-2. A suitable TEA-cocoyl
glutamate is available as Amisoft CT-125 from Ajinomoto USA, Inc. in Teaneck,
New Jersey.
When used as the surfactant in the making of the flexible sheet product of
the present invention, anionic surfactants produce a quick and long lasting lather.
Up to about 47% by weight of anionic surfactant can be added to the base
composition of the present invention. The following are representative
formulations embodying the present invention where anionic surfactants are mixed
with the base composition to form a liquid product composition which may then be
dried to form the soluble sheet product. As used in the Examples 1 through 5
below, the base composition includes about 1.75% PVP K-30, about 13.91%)
AirVol 523 S, about 2.94% propylene glycol, and about 81.4% water.
Example 1
Ingredient Percentage by Weight
Base Composition 20 - 21% Ammonium Laureth Sulfate 20%-24% Deionized Water Balance
Example 2
Ingredient Percentage by Weight
Base Composition 20 - 21% Ammonium Laureth Sulfate 10 - 12% Deionized Water Balance
Example 3
Ingredient Percentage by Weight
Base Composition 89 - 90% Sodium Laureth Sulfate 2.5 - 3% Deionized Water Balance
Example 4
Ingredient Percentage by Weight
Base Composition 20 - 21% Sodium Laureth Sulfate 14 - 18% Deionized Water Balance
Example 5
Ingredient Percentage by Weight
B ase composition 20 - 21 )
TEA-Cocoyl Glutamate 17- 18%
Deionized Water Balance
Nonionic surfactants may also be added to the base composition of the
present invention. However, when used as the only surfactant, such a mixture of
nonionic surfactants with the base composition will not form sheets. Consequently,
in order to achieve the formation of the desired soluble sheet product, it is necessary
to include a companion surfactant, such as an anionic surfactant, cationic surfactant,
amphoteric surfactant, or a surfactant blend. Depending to a degree upon the
nonionic surfactant chosen, up to about between 26% and 30%) by weight of a
nonionic surfactant can be incorporated into the liquid product composition. In
general, nonionic surfactant may be added to the base composition until the point
at which film formation, and, consequently, the formation of the soluble sheet
product, is adversely effected. However, in order to achieve sheet formation, the
total amount of nonionic and other surfactant added should not exceed about 65 >
by weight of the liquid product composition. In order to form satisfactory sheets,
the nonionic surfactant should be added to the base composition in lower levels than
the other surfactants to be included in the mixture.
Cationic surfactants can also be used to form the sheets of the present
invention. Compatible cationic surfactants include DL pyrrolidone carboxylic acid
ethyl cocoyl arginate and sunflowerseedamidopropyl dimethylamine lactate. A
suitable DL pyrrolidone carboxylic acid ethyl cocoyl arginate is available as CAE
from Ajinomoto USA, Inc. in Teaneck, New Jersey. Depending upon the cationic
surfactant selected, up to about between 4.9% and 48% by weight of cationic
surfactant can be incorporated into the liquid product composition. The maximum
level of surfactant will vary depending upon the particular cationic surfactant
chosen. Thus, in order to obtain formation of the soluble sheet product, it has been
discovered that the maximum level of DL pyrrolidone carboxylic acid ethyl cocoyl
arginate that can be added to the liquid composition is about 4.9%) by weight, and
the maximum level of sunflowerseedamidopropyl dimethylamine lactate that can
be incorporated into the liquid product composition is about 12%) by weight. In
general, cationic surfactant may be added to the base composition until the point at
which film formation, and consequently, the formation of the sheet, is adversely
effected.
When DL pyrrolidone carboxylic acid ethyl cocoyl arginate (CAE) is added
to the base composition and dried to form the flexible sheet product, a stretchy, thin
sheet which quickly dissolves in water is formed. In order to prevent over-dryness
of the sheet, the DL pyrrolidone carboxylic acid ethyl cocoyl arginate should be
solublized in propylene glycol prior to addition to the base composition. Following
is a representative formulation embodying the present invention of the combination
of a base composition and surfactant mixture using DL pyrrolidone carboxylic acid
ethyl cocoyl arginate. As used in Example 6 and 7, the base composition includes
about 1.75% PVP K-30, about 13.91% AirVol 523S, about 2.94% propylene
glycol, and about 81.4% water.
Example 6
Ingredient Percentage by Weight
Base composition 20-21% CAE 4 - 4.9%
Propylene Glycol 44 - 45% Deionized Water Balance
"* 1 In mixtures containing DL pyrrolidone carboxylic acid ethyl cocoyl arginate,
foam production of the sheet may be enhanced by the addition of a betaine.
Nevertheless, it has been found that limited foam is generated by a mixture
containing DL pyrrolidone carboxylic acid ethyl cocoyl arginate unless an anionic
surfactant is also added to the mixture. The following is an example of a preferred
16 mixture including DL pyrrolidone carboxylic acid ethyl cocoyl arginate and an
anionic surfactant, sodium laureth sulfate:
Example 7
Ingredient Percentage by Weight
Base composition 19-20%
CAE 2 -3 %
Sodium Laureth Sulfate 7 - 9%
Propylene Glycol 28.5% - 29.5% l',6 Deionized Water Balance
As previously noted, in order to achieve the formation of suitable sheets, the total
amount of cationic and other surfactant added should not exceed about 65% by
weight of the liquid product composition.
Water soluble soaps can also be used in the formation of the soluble sheet
product of the present invention. It can be used to modify the lather generation
potential of the soluble sheet and to slow the solubility of the sheet. Up to about
between 2% and 22% weight of soap can be incorporated into the liquid product
composition, depending upon the soap chosen. In general, soap and synthetic
surfactant may be added to the base composition until the point at which film
formation, and consequently, the formation of the soluble sheet product, is
adversely effected. Soap can be the only surfactant added to the base composition,
or, alternatively, it may be combined with another surfactant for addition to the base
composition. In order to achieve the formation of sheets, the total amount of soap
and synthetic surfactant should not exceed about 65% by weight of the liquid
product composition. Compatible soaps include sodium octonoate and potassium
soaps. The following is an example of a composition using sodium octonoate. As
used in Example 8, the base composition includes about 1.75% PVP K-30, about
13.91% AirVol 523S, about 2.94% propylene glycol, and about 81.4% water.
Example 8
Ingredient Percentage by Weight
Base composition 19.5 - 20.5%
Sodium Octonoate 9 - 10%
Sodium Laureth Sulfate 12 - 15% Deionized Water Balance
Triethanolamine potassium vegetable oil soap is also a compatible soap and
is available as Mackanate WGS from Mclntyre in University Park, Illinois. The
following is an example of a mixture with Mackanate WGS. As used in Example
9, the base composition includes about 1.75% PVP K-30, about 13.91% AirVol
523 S, about 2.94% propylene glycol, and about 81.4% water.
Example 9
Ingredient Percentage by Weight
Base composition 19.5 - 20.5%
Mackanate WGS 19.5 - 20.5%
Deionized Water Balance
Skin feel ingredients, including skin conditioners such as vitamin E acetate,
silicones, petrolatum and aloe may be added to the base composition with or
without a surfactant. When used without a surfactant, a sheet containing such skin
conditioning additives may be applied directly to wet skin, such as right after
bathing or showering. When the sheet with skin conditioning additives is applied
to wet skin, the sheet dissolves leaving the skin conditioner on the skin.
Other skin feel ingredients may also be added to the liquid product
composition to provide visual or perceptual sensory or skin conditioning effects to
the ultimate product. Examples include loofah, jojoba beads, oat hulls, walnut
shells, petrolatum, cyclomethicone, sodium PEG-7 olive oil carboxylate, silicones,
aloe, vitamin E acetate, emollients and humectants. These skin feel ingredients can
be added at levels required for aesthetic sensory perception, or skin conditioning
and have the ability to change the texture of the sheet itself.
Skin feel ingredients added to the liquid product composition at provide
visual perceptual sensory, or skin conditioning effects, may be added at the level
desired by the user; however, the amount of material added should not impair film
formation to create the soluble sheet product. In general, a liquid product
composition. Although up to about 50% by weight of the liquid product
composition may be skin feel ingredients, depending upon the chosen skin feel
ingredient, less than 50% by weight of the liquid product composition may have to
be used in order to avoid adversely effecting the formation of the soluble sheet
product.
The following examples further illustrate the present invention in which skin
feel ingredients which enhance the visual or perceptual sensory or skin conditioning
effects are added. These examples are not intended to limit the invention in any
way. Thus, altering the examples, or even using altogether different ingredients
which are within the scope of the claims is not outside the contemplated invention.
As used in Examples 10 through 14, the base composition includes about 1.75%
PVP K-30, about 13.91% AirVol 523S, about 2.94% propylene glycol, and about
81.4% water.
Example 10
Ingredient Percentage by Weight
Base Composition 19 - 20%)
TEA-Cocoyl Glutamate 18 - 19%
Sodium PEG-7 Olive Oil Carboxylate 7 - 8%
Deionized Water Balance
Example 11
Ingredient Percentage by Weight
Base Composition 21-22%
Sodium Laureth Sulfate 9 - 12%
Sodium PEG-7 Olive Oil Carboxylate 11-12% Deionized Water 28-29%
Example 12
Ingredient Percentage by Weight
Base Composition 22 - 23% Ammonium Laureth Sulfate 10 - 13% High Oleic Sunflower Seed Oil 11 - 12% Perfume, Dye, etc. 1.5 - 2.5% Deionized Water Balance
Example 13
Ingredient Percentage by Weight
Ϊ 6 Base Composition 23.5-24.5% Ammonium Laureth Sulfate 9 - 12% Cetearyl Octonoate 10 - 11% Perfume, Dye, etc. 5 - 6% Deionized Water Balance
;,ι
Example 14
26 Ingredient Percentage by Weight
Base composition 42.5 43.5% Ammonium Laureth Sulfate 13 - 17% Jojoba Ester 2 - 3%
Antibacterial agents such as triclosan, benzethonium chloride,
chlorohexidine gluconate (CHG) and triclocarban may also be incorporated into the
liquid product composition.
In the above examples surfactants are used which are typically used in a
variety of personal care cleansing products. However, surfactants which are usually
employed in household cleaning products such as laundry detergents may also be
used in the soluble sheet product. Such an embodiment has particular application
to treatment of stains on clothing. In this embodiment of the invention, sheets
formed by including such surfactants in the base composition are dampened and
applied to the stained area. The sheet is then allowed to remain on the stained area,
providing treatment to the stain, until washing occurs.
Volatile ingredients such as ethanol, petroleum ether, or isopentane can be
incorporated into the liquid product composition to help enhance the drying of the
soluble sheet product. These volatile materials serve to expand the liquid product,
and, at room temperature, cause a skin to form over the inflated surface of the
product. In the dried soluble sheet product, the skin remains semi-inflated, creating
air pockets, or cells, in the soluble sheet product. Air pockets may also be created
in the soluble sheet product by aerosolizing the liquid product composition.
Alternatively, air pockets may be created in the soluble sheet product by
incorporating surfactant and certain oils into the liquid product composition. For
example, an addition of about 11% of sunflower oil to the base composition and
about 10 - 12% ammonium laureth sulfate results in a soluble sheet product with air
pockets or cells.
Once the desired ingredients have been incorporated into the base
composition, the liquid product composition is preferably is spread onto a relatively
flat surface to dry at room temperature. Alternatively, the liquid may be more
rapidly dried by subjecting it to a heat, such as an oven. It has been found that
drying the liquid product composition in about a 140 °F oven works well. However,
higher temperature can be used for faster drying. Enhanced drying can also be
accomplished through a heated spray system, vacuum, or other known drying
methods.