Skin care sponge

A hydrophilic open-celled poly (urea/urethane) sponge derived from a prepolymer produced by the reaction of a polyoxyalkylene polyol with a stoichiometric excess of an organic polysocyanate, said sponge containing substantially uniformly distributed throughout the pores thereof a readily releasable skin care composition and methods of making same and using same for treating skin. It has of course long been known to treat the skin for various purposes by applying thereto a skin care composition, such application being commonly effected by first impregnating an absorbent fibrous pad or sponge applicator with the composition, or supplying a quantity of such composition to the surface of the pad or sponge applicator, and then transferring said composition to the skin by wiping and rubbing same with the applicator. This method is subject to certain disadvantages, among which are the tiresome and time-consuming repetitive step of first supplying the applicator with a quantity of the composition, the difficulty of controlling the amount of composition so applied to the skin, the tendency to permanently or temporarily misplace the container holding the composition, and the like.

U.S. Pat. No. 3,002,937 discloses a polyester-urethane sponge having 
specified proportions of large and small cells and containing a releasable 
detergent but no skin care component as such, and the method of producing 
same is further disadvantageous in requiring careful selection of the 
emulsifying agent employed in the foaming reaction and the use of small 
proportions of the bubble or cell producing water reactant, thereby 
limiting the amount of detergent dissolved therein for incorporation in 
the foaming reaction and resulting impregnated sponge. 
U.S. Pat. No. 3,810,841 also discloses a polyesterurethane sponge 
containing a releasable synthetic detergent composition, the method of 
producing same also involving the use of relatively small proportions of 
water reactant and incorporating the detergent, optionally in combinations 
with a dry emollient such as ethoxylated lanolin or high molecular weight 
polyethylene glycols, in the form of dry solid particles in the 
non-aqueous polyurethane-forming reactant prior to addition thereto of the 
water reactant. This method is thus further disadvantageous in requiring 
careful control of the sizes of the dry solid particles to conform with 
the cell strand thicknesses and the cell or pore sizes of the sponge, in 
being limited to the use of dry solid particles as releasable functional 
agents, and their addition only to the non-aqueous polyurethane-forming 
reactant and none to the water reactant, thereby sacrificing the 
homogenizing and/or solubilizing action of water. 
U.S. Pat. No. 3,007,883 discloses a polyurethane sponge also prepared with 
a small proportion of water reactant, the foaming reaction being conducted 
in the presence of a small proportion of lecithin, optionally with an 
emulsifier to control the pore structure of the sponge. The patent refers 
to the prior use of surface active agents, including lanolin and lecithin, 
as emulsifying agents to control pore size, but neither such prior art nor 
the patented subject matter involves, teaches or contemplates a sponge 
product impregnated with a releasable functional agent, much less a skin 
care composition. 
Further, most if not all of the foaming procedures of the above-discussed 
patents involve unduly long setting or curing periods. 
It is an object of this invention to provide a device and methods which 
will not be subject to one or more of the above disadvantages. Another 
object of the invention is the provision of an improved form of skin care 
sponge. Still another object of the invention is the provision of a sponge 
product containing relatively large amounts of skin care composition in 
readily releasable form and over longer periods of time or cycles of use. 
A further object of the invention is the provision of of improved methods 
for producing such products. Yet a further object of the invention is the 
provision of such methods involving shorter setting or curing periods 
and/or better means of controlling the foaming reaction and the structure 
of the resulting sponge and the like. And a still further object of the 
invention is the provision of improved methods of treating skin employing 
such products. Other objects and advantages will appear as the description 
proceeds. 
The attainment of the above objects is made possible by this invention 
which includes the provision of a hydrophilic open-celled poly 
(urea/urethane) sponge derived from a prepolymer produced by the reaction 
of a polyoxyalkylene polyol with a stoichiometric excess of an organic 
polysocyanate, said sponge containing substantially uniformly distributed 
throughout the pores thereof a readily releasable skin care composition 
and methods of making same and using same for treating skin. 
According to a further aspect of this invention, the above-defined sponge 
is prepared by reacting said prepolymer with an aqueous dispersion 
(including emulsion or solution) of the skin care composition containing 
about 30 to 200% of water by weight of the prepolymer. The water in said 
dispersion reacts in known manner with isocyanate groups in the prepolymer 
to release carbon dioxide gas bubbles which produce the desired foam or 
sponge product containing the in situ impregnated skin care composition 
substantially uniformly distributed throughout its pores in readily 
releasable form due to the open or reticulated pore or cell structure of 
the product. 
According to a still further aspect of this invention, an improved skin 
treating method is provided simply by rubbing or wiping the skin with the 
above-defined impregnated sponge, desirably after first moistening the 
sponge with water or other aqueous medium to facilitate release of the 
skin care composition therefrom and, when a flexible sponge is employed, 
to soften the sponge. The sponge can be used repeatedly, additional 
amounts of skin care composition being released each time by suitable 
squeezing of the sponge. When the skin care composition is a liquid, e.g., 
an oil, the physical squeezing action is sufficient to release the 
composition to the surface of the sponge, but desirably such release is 
facilitated by the emulsifying action of surface active agents in the 
composition. When the skin care composition is a fatty, unctuous, greasy, 
or slippery solid, the physical squeezing action is generally insufficient 
and release to the surface of the sponge must generally be aided or made 
possible by the emulsifying action of said surface active agent in the 
composition, in conjunction with the sponge-moistening aqueous medium. 
When such surface active agent is present in the skin care composition, it 
will accordingly be understood that most if not all the emollient will be 
applied to the skin in the form of an oil-in-water or water-in-oil 
emulsion, or an aqueous dispersion. 
When the sponge is finally depleted of its supply of skin care composition, 
it may be employed in the manner of an unimpregnated natural or synthetic 
sponge. The sponge products per se generally have densities of about 3 to 
6 lbs./ft..sup.3, have a wide range of pore sizes varying from about 30 to 
100 pores per inch (ppi), and hold about 10 to 20 times their own weight 
of water. 
Methods of preparing hydrophilic open celled poly (urea/urethane) sponges 
or foams from an isocyanate capped prepolymer produced by reaction of a 
polyoxyalkylene polyol with a stoichiometric excess of an organic 
diisocyanate, by addition thereto and reaction therewith of suitable 
proportions of water, especially relatively large amounts of water ranging 
from about 30 to 200% by weight of the prepolymer, are known and no claim 
is accordingly made thereto per se. For example, reference is made to such 
methods and products disclosed in U.S. Pat. No. 3,833,386, which 
disclosures are incorporated herein by such reference. Somewhat similar 
disclosures are to be found in U.S. Pat. Nos. 3,598,772 and 3,171,820, in 
"German Plastics Practice" published by Debell and Richardson, 1946, 
Chapter 21, "Plastic Foam," pages 462-465 and in "Papers Presented at the 
Atlantic Meeting: Synthesis of Isocyanate Polymers" published by the 
American Chemical Society, Division of Paints, Plastics and Printing Ink 
Chemistry, September, 1956. Applicants however claim as their essential 
inventive concept the inclusion or dispersion of an emollient composition, 
especially those of the type disclosed below, into the said water reactant 
prior to its admixture and reaction with said prepolymer, thereby enabling 
the attainment of the desired improved and unexpected results. 
According to a preferred embodiment, the isocyanate capped prepolymer is 
formulated in such a manner as to give crosslinked, three dimensional 
network polymers on reaction with water to cause foaming, namely by use of 
a prepolymer having an average isocyanate functionality greater than 2 and 
up to about 6 or more depending on the composition of the polyol and 
capping agent components. In generaly, such prepolymers may be prepared by 
reacting a polyol having an average hydroxyl functionality greater than 2, 
such as polyoxyethylenated glycerol, trimethylolpropane, 
trimethylolethane, tetramethylolbutane, pentaerythritol, or sucrose or 
mixtures thereof or the like, with a stoichiometric excess of an organic, 
preferably aromatic, diisocyanate or polyisocyanate or mixture thereof. 
Alternatively, any polyoxythylenated polyol or mixture thereof may be 
reacted with a polyisocyanate having an average isocyanate functionality 
greater than 2 such as triphenyl methane-4,4',4"-triisocyanate, 
benzene-1,3,5-triisocyanate, toluene-2,4,6-triisocyanate, PAPI (Upjohn; 
polymethylene polyphenylisocyanate having nearly 3 isocyanate groups per 
molecule and an isocyanate equivalent weight of 133; U.S. Pat. No. 
2,683,730), or mixtures thereof or the like. 
The polyoxyethylene polyol reactants are water soluble reaction products 
derived from the polymerization of ethylene oxide in the presence of a 
polyhydroxy compound such as water, ethylene glycol, propylene glycol, 
butylene glycol, diethylene glycol, and the polyhydroxy compounds 
described above and may have a weight average molecular weight of about 
200 to 20,000, preferably about 600 to 6,000. These polyols may contain up 
to 40 mole percent, preferably up to 25 mole percent or less of a 
relatively hydrophobic comonomer such as propylene or butylene oxide in 
the form of a random or block copolymer. 
Useful polyisocyanates other than those referred to above include the 
following diisocyanates: xylene-, chlorophenylene-, diphenylmethane-4,4'-, 
naphthalene-1,5-, 3,3'-dimethyl-4,4'-biphenylene-, 
2,2',5,5'-tetramethyl-4,4'-biphenylene-, 4,4'-sulfonylbis (phenyl)-, 
4,4'-methylene orthotolyl-, hexamethylene-, ethylene-, trimethylene-, 
tolyene-diisocyanate, the corresponding isothiocyanates, and the like. The 
mixed 80/20 tolylene 2,4/2,6 isomers are preferred. 
A stoichiometric excess of the polyisocyanate reactant is generally 
employed to assure complete capping, such as in about a 1.1 to 4:1 
preferably about 2 to 3:1 molar ratio of isocyanate to hydroxyl. The 
reaction may be carried out in an inert moisture-free atmosphere such as 
under a nitrogen blanket at atmospheric pressure at a temperature in the 
range of from about 0.degree. C. to about 120.degree. C. for up to 20 or 
more hours. 
In contrast to the usual polyurethane foam reactions involving use of the 
theoretical 1/2 mole of water per mole of --NCO, the presently preferred 
process employs from about 30 to 200% of water by weight of the capped 
prepolymer, or about 6.5 up to about 390 moles of water, desirably about 
20 to 200 moles of water per NCO group. This large amount of water aids in 
enabling the attainment of improved and unexpected results by inclusion 
therein of increased amounts of the skin care composition in addition to 
improvements in the properties of the sponge structure per se. 
The skin care compositions useful in the practice of this invention are 
well known per se and may have a wide variety of uses, functions or 
purposes. As exemplary of such uses and compositions, in the physical form 
of liquids, oils, creams, lotions, pastes, ointments, and (preferably 
fatty, unctuous, greasy, waxy or slippery), solids and the like, there may 
be mentioned baby skin preparations, bath oils, skin softening, 
conditioning, rejuvenating, relaxing, soothing, analgesic, antiseptic, 
antibiotic, germicidal, cleansing, after-shave, sunscreen, emollient, 
make-up, protective, perfume, deodorant, anti-perspirant, burn, massage, 
liniment and other skin preparations and the like. In addition to the 
necessary dosage amount of any active functional ingredient required for 
obtaining the desired effect on the skin, such skin care compositions 
generally contain an emollient component to control or neutralize any 
detrimental effects of the functional ingredient on the skin and/or to 
retain or improve, the condition of the skin. 
The emollient materials useful in the sponge products and processes of this 
invention are generally organic oils or unctuous (fatty, waxy, slippery, 
greasy) solids, synthetic or of animal/vegetable or mineral origin, well 
known in the art for improving conditioning, relaxing, softening and/or 
soothing the skin. They are generally water insoluble or water-dispersible 
but may be water soluble. Examples of suitable emollient substances 
include liquid and solid petrolatum, silicones, theobroms, almond, orris, 
olive, palm, coconut, cottonseed, corn and other vegetable oils, 
sulfonated oils, cholesterol, lanolin and derivatives such as 
polyoxyethylenated and polyoxypropylenated lanolin, spermaceti, natural 
and synthetic fatty esters and salts such as polyglycol stearate, glyceryl 
mono-, di- and tri-stearates, isopropyl sebacate and myristate, sorbitan 
sesquioleate and calcium and aluminum stearates, higher fatty alcohols 
such as cetyl, oleyl and stearyl alcohols, polyethylene glycol, e.g. M.W. 
1500 and mixtures thereof and the like. 
According to a preferred embodiment of the invention, there is included in 
the aqueous skin care compositions employed in the practice of this 
invention a surfactant, preferably those which are nonionically or 
anionically surface active. These surfactants, in addition to stabilizing 
and improving the foaming action and cell structure of the sponge, perform 
multiple functions in the said skin care compositions and the resulting 
impregnated sponge products of the invention. Thus, they act as 
emulsifying or dispersing agents for dispersing the composition in the 
water reactant medium and subsequently in the remoistening aqueous medium, 
facilitate the skin treating use of the sponge product, improve the 
uniformity of the resulting film of skin care composition on the skin, and 
perform a simultaneous detersive function on the skin. 
Suitable surfactants of the nonionic type include, for example, 
polyoxyethylenated higher molecular weight reactive hydrogen-containing 
compounds such as the reaction products of about 2 to 30 moles of ethylene 
oxide with 1 mole of such compounds containing about 6 to 20 or more 
carbon atoms including fatty acids such as palmitic acid, monohydric and 
polyhydric alcohols such as Oxotridecyl alcohol (from tetrapropylene or 
triisobutylene), oleylalcohol, lauryl alcohol and polyoxypropylene glycol, 
and alkyl phenols such as nonyl phenol, and mixtures thereof and the like. 
Suitable surfactants of the anionic type include the sodium, potassium, 
ammonium and amine salts of the sulfate and primary and secondary 
phosphate esters of the above-described polyoxyethylenated nonionic 
surfactants, such salts of fatty acids (soaps), of alkyl aryl sulfonic 
acids such as dodecylbenzene sulfonic acid, of fatty alcohol sulfates and 
phosphates such as lauryl sulfate and phosphate, of the sarcosinic acids, 
of lauryl sulfoacetic acid, of N-acyl taurides such as N-oleoyl-N-methyl 
tauride, of higher ethers and esters of isethionic acid, and mixtures 
thereof and the like. 
In preparing the sponge products of this invention, there are in general 
employed, by weight of the prepolymer, about 30 to 200% and preferably 
about 60 to 120% of tap or deionized water, about 6 to 100% and preferably 
about 10 to 30% of the skin care composition of which about 5 to 100% may 
be an emollient substance, and preferably about 2 to 12% of the 
surfactant, the higher ranges of about 6 to 12% of the surfactant being 
preferred when a simultaneous cleansing function on the skin is desired. 
Other known types of surfactants may be included in the aqueous reactant to 
stabilize and improve the cell or pore structure of the sponge, such as 
from about 0.5 to 5%, by weight of the prepolymer, of Union Carbide's 
Silicone L-520, Dow Corning DC-200 silicone stabilizer, and the like. 
In some instance, some degree of simultaneous abrading action on the skin 
may be desired, for example to remove dead tissue or the like. For this 
purpose a small amount, for example, about 0.5 to 5%, of a finely divided 
abrasive material having a maximum diameter less than the pore size of the 
sponge structure may be included to permit the material to be readily 
released from the sponge. Generally, such abrasive particles should have a 
diameter ranging from about 1 to 100 microns. Examples of suitable 
abrasive materials include without limitation kaolin, clay, diatomaceous 
earth, calcium carbonate, pumice, talc, chromium oxide, iron oxide, fused 
synthetic aluminum oxide, garnet, permetite, feldspar, and the like. Such 
materials may be admixed with either the aqueous reactant or the 
non-aqueous prepolymer reactant. 
Another useful additive to the water reactant, generally in weight 
concentrations of about 0.02 to 2%, is an emulsion stabilizer, thickener 
and/or protective colloid such as triethanolamine sulfate, 
carboxymethylcellulose, polyvinylpyrrolidone, polyacrylic acid, and the 
water insoluble but water swellable acidic carboxylic cross-linked 
polymers commercially available as Carbopols and disclosed in U.S. Pat. 
Nos. 2,798,053; 2,923,692 and 2,980,655. 
Other optional additives to the water reactant include dyes, stains, 
pigments, UV absorbers (0.2-0.5%), optical brighteners (0.02-5%), 
antistatic agents (0.03-1%), wet slip improvers such as Union Carbide's 
Polyox water soluble resin, perfumes, germicides such as hexachlorophene, 
polyvinyl pyrrolidone-iodine complex iodophor, and 
phenoxypolyethoxyethanol-iodine iodophor, sequestering agents such as 
tetrasodium ethylenediamine tetraacetic acid, and the like. Insoluble 
additives in particulate form may be admixed with the water reactant or 
the prepolymer. 
The foaming or sponge-producing reaction between the described aqueous skin 
care composition (water reactant) and the isocyanate-capped prepolymer is 
carried out in known manner, as by simply and quickly thoroughly mixing 
them prior to initiation of substantial gas bubble formation, pouring the 
mixture into a mold, on a moving belt or the like, or employing injection 
procedures, and permitting the foam to rise and set. The reaction is 
exothermic, and may be controlled if desired within a temperature range of 
about 10.degree. to 100.degree. C. Higher temperatures within this range 
hasten the reaction, as would inclusion of known catalysts such as tin 
compounds, for example stannous octoate, and amines, for example trimethyl 
amine, N-methyl- and N-ethylmorpholine and the like. 
Following completion of the foaming reaction, generally in about 1 to 10 
minutes, the impregnated sponge product is preferably dried, if desired 
under vacuum of about 1 to 760 Torr at a temperature of about 0.degree. to 
150.degree. C. and may be cut to any desired size. 
If desired, about 2 to 20%, preferably about 5 to 10%, of diisocyanate 
reactant, preferably tolylene diisocyanate, or other cross-linking agent, 
by weight of the prepolymer may be preliminarily admixed therewith for the 
purpose of obtaining a lower density, larger pore size sponge structure. 
Adjustment of the above proportions and/or other known means may be 
employed to produce a more flexible or more rigid foam or sponge 
structure. Increased hardness and/or rigidity may for example be 
particularly desirable if a simultaneous abrading action on the skin is 
needed.

The following examples are only illustrative of preferred embodiments of 
this invention. All parts and proportions referred to herein and in the 
appended claims are by weight unless otherwise indicated. 
PREPOLYMER A 
A solution of 92 grams of glycerol representing 1 mole, 3 eq. OH, and 1000 
grams of polyoxyethylene glycol 1000 representing 1 mole, 2 eq. OH is 
outgassed at 100.degree. C. and 10 Torr for 2 hours. To the outgassed 
solution is added 870 grams representing 5 moles tolylene diisocyanate 
consisting of an 80/20 mixture of 2,4/2,6 isomers. The reaction solution 
is stirred at 60.degree. C. for 4 hours whereupon the actual isocyanate 
content reaches a constant 2.49 meq. NCO/gram relative to a theoretical 
content of 2.54. The resin product has a pale orange color, a density of 
1.10 and a viscosity (Brookfield No. 4 spindle) at 25.degree. C. of 13,400 
cps. 31.3 parts of the resin product representing 50 mole percent has a 
theoretical molecular weight of 615 as represented by the reaction product 
of 1 mole of glycerol with 3 moles of tolylene diisocyanate, while 68.7 
parts of the resin product representing 50 mole percent has a theoretical 
molecular weight of 1348 as represented by the reaction product of 1 mole 
of polyoxyethylene glycol, M.W. 1000, with 2 moles of tolylene 
diisocyanate. 
PREPOLYMER B 
The above procedure is repeated except for using a polyoxyethylene glycol 
having a weight average molecular weight of 4,000. Corresponding results 
are obtained. 
PREPOLYMER C 
A slurry of 100 grams of pentaerythritol, 0.735 mole having 2.94 eq. OH in 
860 grams of tolylene diisocyanate, 4.95 moles having 9.9 eq. NCO 
groups/gram and the mixture ratio of 80/20 of 2,4/2,6 isomers is stirred 
for 24 hours. An orange solution results. To the orange solution is added 
1000 grams outgassed polyoxyethylene glycol representing 1 mole having 2.0 
eq. OH. These reactants are stirred at about 67.degree. C. for 4 hours 
followed by additional stirring at 25.degree. C. for 16 hours whereupon 
the isocyanate content reaches a constant level of 2.63 meq. NCO 
groups/gram relative to a theoretical value of 2.56. The resultant product 
has an orange color, a viscous consistency at 25.degree. C., and upon 
analysis is found to be a solution of about 31 percent by weight (42.5 
mole percent) of the reaction product of 1 mole of pentaerythritol with 4 
moles of tolylene diisocyanate having a theoretical molecular weight of 
832, in about 69 percent by weight (57.5 mole percent) of the reaction 
product of 1 mole of polyethylene glycol, M.W. 1000 with 2 moles of 
tolylene diisocyanate having a theoretical molecular weight of 1348. 
EXAMPLE 1 
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T I 0.4 gram Herbal Floral perfume 
40.0 grams floating bath oil consisting of 
1% Solulan PB-20 emollient liquid 
(1 mole lanolin alcohol reacted with 
20 moles propylene oxide-Amerchol) 
5% Ameroxol OE-2 water-in-oil 
emulsifier liquid (1 mole oleyl alcohol 
reacted with 2 moles ethylene oxide, 
fragranted-Amerchol). 
10% Acetulan spreading, penetrating, 
degreasing and emollient liquid agent 
(acetylated lanolin alcohol-Amerchol) 
56% mineral oil (70 vis.) 
28% isopropyl palmitate 
T II 14.0 grams Pluronic L-64* 
86.0 grams tap water 
T III 
200.00 grams 
PREPOLYMER A 
______________________________________ 
*Reaction product of 60% polyoxypropylene glycol M.W. 1750 with 40% 
ethylene oxideWyandotte. 
Part I is thoroughly dispersed in Part II, and the resulting mixture added 
all at once to Part III, (previously fluidized by warming to 50.degree. 
C.) with vigorous agitation which is continued until creaming occurs 
(about 30 seconds) caused by initial formation of visible CO.sub.2 
bubbles. The mixture is then poured into a 9".times.9".times.2" 
Teflon-coated pan and the foam allowed to rise and set or cure (within 
about 5-7 minutes). The resulting impregnated hydrophilic flexible 
open-celled poly (urea/urethane) sponge product, desirably after drying at 
room or elevated temperatures up to 100.degree. C., and cutting to any 
desired size, is found to be highly effective as a skin conditioner and 
cleanser during a number of bathings until depleted of the impregnated 
skin care composition. 
EXAMPLE 2 
The procedure of Example 1 is repeated using PREPOLYMER B as Part III. 
Similar results are obtained. 
EXAMPLE 3 
The procedure of Example 1 is repeated using PREPOLYMER C as Part III. 
Similar results are obtained. 
EXAMPLE 4 
The procedure of Example 1 is repeated except that the floating bath oil is 
replaced by 4.0 grams of the same said mineral oil, the resulting sponge 
product being highly effective as a skin conditioner, softener and make-up 
remover during many use cycles till depleted of the skin care composition. 
EXAMPLES 5 and 6 
The procedure of Example 4 is repeated using, respectively, PREPOLYMERS B 
and C as Part III. Similar results are obtained. 
EXAMPLE 7 
The procedure of Example 1 is repeated except that the floating bath oil is 
replaced by 35.0 grams of Solution PB-2, a soft solid reaction product of 
1 mole of lanolin alcohol with 2 moles of propyleneoxide (Amerchol). The 
resulting sponge product is similar to that of Example 4. 
EXAMPLES 8 and 9 
The procedure of Example 7 is repeated using, respectively, PREPOLYMERS B 
AND C as Part III. Similar results are obtained. 
This invention has been disclosed with respect to certain preferred 
embodiments, and it will be understood that various modifications and 
variations thereof which will become obvious to persons skilled in the art 
are included within the spirit and purview of this application and the 
scope of the appended claims.