US 3577516 A
Description (OCR text may contain errors)
1971 F. E. souu: E
PREPARATION or sun on BANDAGE Filed D60. 3, 1969 1 mvsm'oag mic/$56 0 04 p wwlgyh ATTORNEYS United States Patent 3,577,516 PREPARATION OF SPRAY 0N BANDAGE Francis E. Gould, Princeton, and Thomas H. Shepherd,
Hopewell, N.J., assignors to National Patent Development Corporation, New York, N.Y.
Continuation-impart of applications Ser. No. 567,856,
July 26, 1966, now Patent No. 3,520,949, Ser. No.
650,259, June 30, 1967, and Ser. No. 654,044, July 5,
1967. This application Dec. 2, 1969, Ser. No. 881,376
Int. Cl. A611 15/00 US. Cl. 424-46 17 Claims ABSTRACT OF THE DISCLOSURE A bandage is formed in situ on a wound by spraying on separately or simultaneously a hydrophilic water insoluble polymer and a high boiling plasticizer or solvent therefor. Preferably the polymer is a hydroxy lower alkyl acrylate or methacrylate. Medically active ingredients can be included in the composition.
The present application is a continuation-in-part of application Ser. No. 567,856 filed July 26, 1966 now Pat. 3,520,949 issued July 21, 1970; application Ser. No. 650,259, filed June 30, 1967 and now abandoned; and application Ser. No. 654,044, filed July 5, 1967.
The present application relates to spray-on bandages.
A spray-on bandage offers a convenient, easy method of protecting minor wounds, cuts and/or abrasions during the healing process, and avoids certain undesirable characteristics associated with the use of substrates coated with pressure sensitive adhesives and gauze pads; such as pain and peeling of hair during removal, disagreeable appearance, adhesion of the healing area to the gauze pad, etc. i
The requirements for a fully acceptable spray-on bandage include the following:
(1) It protects the wound from air borne bacteria and dirt.
(2) It has moisture vapor permeability sufiicient to prevent accumulation of aqueous fluid under the bandage.
(3) It must be non-toxic and non-irritating to the skin.
(4) It should not adhere to the wound area or permit infiltration by regenerating tissue.
(5) It should not cause a burning or stinging sensation when applied.
(6) It should not be water soluble or rendered tacky by contact with water to avoid dirt accumulation.
(7) It should be readily removeable when desired.
Prior art spray-on products suffer from a number of disadvantages with respect to the above criteria. Thus prior art materials having the desired moisture vapor permeability coupled with water resistance must be applied as a spray from alcohol or similar solvent solution which causes a strong burning sensation in the wound area.
It is an object of the present invention to develop a spray-on bandage having all seven of the above set forth desirable characteristics while avoiding the disadvantages of prior art spray-on bandages.
Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific Patented May 4, 1971 example, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
It has now been found that these objects can be attained and a film forming action can be caused by applying a mixture of a powder of certain water insoluble, hydrophilic polymers having a high moisture vapor permeability with high boiling non-toxic polar plasticizer solvents therefore to, in effect, create a room temperature gelling plastisol which has high moisture vapor permeability, is sufficiently adherent to the skin to remain in place for extended periods of time, and adequately protects wound areas from contamination. Films produced by this technique are readily removed by soaking the bandages area in water for a few minutes which loosens the bond between the plastisol film and the skin. The film can then be readily pulled from the skin surface without discomfort.
The invention can be used to form spray-on bandages not only for human wounds but also is useful in the field of veterinary medicine for wounds on the skins of animals such as dogs, cats, sheep, cattle (e.g. to protect cows having mastitis on their teats), goats, pigs and horses and zoological animals such as lions, tigers, deer, zebra, etc.
Furthermore there can be incorporated in the films of the invention medically active ingredients which will diffuse from the film to the wound area over extended periods of time and keep the wound area free from infection, or provide local anesthesia or analgesia properties.
The medically active ingredients can be incorporated in the film by either 1) having them impregnated in the polymer or (2) mixing the active ingredient with the polymer powder, or (3) dissolving or dispersing the active ingredient in the high boiling plasticizer-solvent.
Polymer powders useful in this invention include polymers of hydroxy lower alkyl acrylates and methacrylates alone or coplyrners with each other, e.g. copolymers of 1 to 99% of each. Such polymers include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxy propyl acrylate and hydroxypropyl methacrylates. The preferred polymers are hydroxy lower alkyl methacrylates, especially hydroxyethyl methacrylate polymers.
There are also be used copolymers of the hydroxyalkyl acrylates and methacrylates with up to weight percent of lower alkyl acrylates and methacrylates, e.g. methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate and butyl methacrylate, hydroxy lower alkoxy lower alkyl acrylates and methacrylates, e.g. diethylene glycol monoacrylate, diethylene glycol mono methacrylate, dipropylene glycol mono acrylate, dipropylene glycol mono methacrylate, acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-ethyl acrylamide, Nethyl methacrylamide, N- propyl acrylamide, N-propyl methacrylamide, N-isopropyl acrylamide, N-isopropyl methacrylamide, lower alkoxy lower alkyl acrylates and methacrylates such as methoxyethyl acrylate, methoxyethyl methacrylate, ethoxyethyl acrylate and ethoxyethyl methacrylate, amine compounds, e.g. p-aminostyrene, 2-amino-4- vinyltoluene, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, piperidinoethyl acrylate, 2-vinyl pyridine, dimethylaminopropyl methacrylate, diacetone acrylamide, diacetone methacrylamide, N- vinyl pyrrolidone.
The copolymerizable material should not be used in such amount as to reduce the compatibility of the hydroxyalkyl acrylate or methacrylate with the solvent or plasticizer or render it either too soluble in water or reduce its hydrophilic properties too greatly.
Usually the hydroxyalkyl acrylate or methacrylate is at least 80% by weight of the total monomers.
Useful, but less preferable, copolymers are prepared from lower alkyl acrylates and methacrylates, e.g. having 1 to 3 carbon atoms in the alkyl group such as methyl acrylate, ethyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate and propyl methacrylate with 3080% of ethoxyethyl acrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, acrylamide, methacrylamide, n-alkyl substituted acrylamides and methacrylamides such as N-methyl acrylamide, N-propyl acrylamide, N-methyl methacrylamide and N-isopropyl methacrylamide and N-vinyl pyrrolidone. Also polymers of the alkyl acrylates and methacrylates with 30-50% of hydroxyethyl and hydroxy propyl acrylates and methacrylates are included in this less preferred category.
In addition to the monomer and monomer mixtures set forth above to prepare polymers there can be added to the monomer or monomer mixture up to 15% by weight of the total monomers of acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid.
While in Shepherd patent 3,428,043 there is described the use of a bandage comprising a fabric having an infrequently cross-linked hydrophilic polymer combined therewith the polymers of the present invention unlike those set forth in the Shepherd patent are substantially devoid of cross-linking. Thus while the slight amount of crosslinking ethylene glycol dimethacrylate impurity (about 0.1 to 0.2% normally present in hydroxyethyl methacrylate can be tolerated any cross-linking agent present should not be sufiicient to interfere with compatibility of the hydrophilic polymer with the plasticizer-solvent so as to prevent plastisol formation or otherwise interfere with the formation of the bandage on the wound.
The presently most preferred polymer is Hydron S, a commercially available polymer of hydroxyethyl methacrylate. It is essentially a homopolymer except for the presence of a trace (about 0.1% by weight) of ethylene glycol dimethacrylates.
The main requirements of the polymers useful in the present invention are:
(2) Sufficient hydrophilic character to possess moisture vapor permeability of at least 200 grams/sq. meter/ 24 hours/mil, preferably at least 500 grams/sq. meter/24 hours/mil.
(3) Susceptibility to solvation (plastisol formation) by the useful polar plasticizer-solvents.
(4) Insolubility in water.
(5) Sufficient friability to be able to be prepared as a finely divided powder, e.g. less than 100 mesh and preferably less than 200 mesh (Tyler Screen series).
Plasticizer-solvents useful for film formation in combination with the polymer-powders include water soluble polar compounds including glycols such as propylene glycol, ethylene glycol, trimethylene glycol, butanediol-1,3, butanediol-l,4, hexanediol-2,5, 2-methyl-2,4-pentanediol, heptanediol-2,4, 2-ethyl-1,3-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycols and other polyethylene glycols having a molecular weight up to 800 (e.g. hydroxy terminated polymers of ethylene oxide having average molecular weights of 200 800), dipropylene glycol, tripropylene glycol and other polypropylene glycols having molecular weights up to 900, propylene glycol nionoethyl ether, mono acetin, trl(hydroxyethyl) citrate,
di(hydroxypropyl) oxalate, hydroxypropyl acetate, glyceryl triacetate, glyceryl tributyrate, liquid sorbitolethylene oxide adducts, liquid glycerine-ethylene oxide adducts, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol diacetate.
The ratio of the plasticizer-solvent to the polymer is not particularly critical and satisfactory results are obtained in the range of from %-20% polymer to 20%- 80% plasticizer-solvent, more preferably 3070% polymer to 70-30% plasticizer-solvent.
Unless otherwise indicated, all parts and percentages are by weight.
In practice, it has been found that a light application of the plasticizer-solvent to the skin followed by application of the polymer powder results in adherence of a sufficient quantity of the powder to the area wet with the plasticizer-solvent to result in a strong, tough, adherent film. The film can be built up to any desired thickness but is usually about 10 mils.
The spray-on bandage of this invention is most conveniently applied using aerosol spray techniques although a layer of liquid followed by a layer of polymer can be applied by brushing, dabbing, etc. The bandage may be applied by a Z-separate spray technique wherein the plasticizer-solvent is first applied, followed by application of the powder from a separate container. Alternatively, the powder and liquid may be applied simultaneously from separate aerosol cans and valves which have a common activating mechanism. In some cases the powder and liquid may be applied from the same can in which case, the presence of the propellant in the can prevents solvation and agglomeration of the powder by the plasticizer solvent.
Suitable propellants include those well known in the art. There can be used compressed gases such as carbon dioxide, nitrous oxide, nitrogen, liquified volatile hydrocarbons such as propane, n-butane, isobutane and 2-methyl butane, methylene chloride, vinyl chloride, fluorinated compounds including perhalogenated compounds and fluorinated hydrocarbons such as dichlorodifiuoromethane (Freon l2), trichlorofluoromethane, 1,2-dichlorotetrafluoroethane, octofiuorocyclobutane, chlorodifiuoromethane, 1,1-difluoroethane, vinyl fluoride, vinylidene fluoride, l-chloro-l,t-difluoroethane. The propellant should contain a substantial amount of volatile material boiling at not over 20 C., but there can also be present a significant amount of less volatile material boiling up to 50 C.
The invention will be understood best in connection with the drawings wherein:
FIG. 1 is a perspective view illustrating the spraying of the plasticizer-solvent according to the invention;
FIG. 2 is a perspective view showing the spraying of the polymer;
FIG. 3 is a view of the finishing bandage; and
FIG. 4 is a view of an alternative method according to the invention.
Referring more specifically to FIGS. 1 and 2 of the drawings there is shown a skin area 2, e.g. on the arm, having a cut 4 thereon. From aerosol can 6, there is directed a spray 8 of appropriate plasticizer-solvent, e.g. propylene glycol by means of propellant, e.g. dichlorodifluoromethane. After the spraying of the plasticizer-solvent is completed, there is then sprayed from aerosol can 10 powdered Hydron S 12 on top of the plasticizer solvent. The Hydron S merges with the plasticizer-solvent to form the completed bandage 14 as a plastisol as shown in FIG. 3.
In the form of the invention illustrated in FIG. 4 a single aerosol can 16 is provided with a chamber 18 for the Hydron S and a separate chamber 20 for the propylene glycol plasticizer-solvent. When valve 22 is operated in the direction of the arrow, it releases the polymer 18 and plasticizensolvent together with the propellant as shown to coat the wound 24 on skin 26 to provide a bandage.
Example 1 This example illustrates the use of a technique of forming a spray-on bandage which does not possess all of the advantages of the invention.
Into a 6 ounce aerosol can was charged 10 grams of a 10% solid solution of Hydron S in 45 grams of 95% ethanol and 20 grams of methylene chloride. The can was sealed with a valve and 25 cc. of Freon 12 were added as the propellant. The resulting spray placed a good film upon the skin surface but was objectionable because of inherent sting response when applied to the wound. Replacement of a portion of the ethanol with water did not appreciably decrease the sting.
POWDER SPRAYS Example 2 In this example a two can system was employed.
Component A was made by charging a six ounce aerosol can with 20 grams of propylene glycol, sealing with a dispensing valve and then additionally charging with 80 cc. of Freon 12.
Component B was made by charging a six ounce aerosol can with 10 grams of Hydron S powder (270 to 325 mesh, Tyler sieve), sealing with a powder valve and further charging with a mixture of 10 grams of methylene chloride and 20 cc. of Freon 12.
For use, a light coat of Component A (liquid) was sprayed upon skin, e.g. a hand having a cut therein, leaving a wet film. The wet film was then oversprayed with Component B (powder) until the skin area was white and slightly dusty. Within 10-30 seconds the powder and liquid coalesced to form a flexible protective skin coating which was readily removable after soaking the hand in water.
In Examples 3-6 a one can system was employed.
Example 3 A single, two chambered aerosol can assembly was utilized in conjunction with a conventional codispensing valve assembly. Filling was as follows:
A six ounce aerosol can was charged with 10 grams of Hydron S powder, 220 to 325 mesh, and sealed with a co-dispensing valve and bag assembly. The bag chamber was then charged with a mixture of 8 grams of propylene glycol and 32 grams of Freon 12. Depression of the valve button then codispersed powder and liquid which formed a skin covering over a wound, e.g. on the hand.
Example 4 To alter humectant, physical and adhesive properties of the final spray-on bandage other coalescent solvents can be used in combination with or in replacement of propylene glycol. Numerous solvents of this type are set forth above. Among the preferred solvents of this type are glycerine, polyethylene glycol, monoacetin and triacetin.
A six ounce aerosol can was charged with 10 grams of Hydron S powder, 270 to 325 mesh and sealed with a codispensing valve and bag assembly. The bag chamber was then charged with a mixture of 4 grams of glycerine, 4 grams of propylene glycol and 32 grams of Freon 12. The resulting bandage showed increased humectant properties and good adhesion to the skin surrounding a wound, eg on a leg.
Example 5 The procedure of Example 4 was repeated replacing the propylene glycol by 4 grams of polyethylene glycol 200 (polyethylene glycol having an average molecular weight of about 200) to obtain a bandage on the skin over and around the wound.
Example 6 The procedure of Example 4 was repeated replacing the propylene glycol by 4 grams of triacetin to obtain a satisfactory bandage over the wound.
Example 7 The procedure of Example 2 was repeated replacing the propylene glycol by polyethylene glycol 200 to obtain a satisfactory bandage.
Example 8 As previously pointed out in place of Hydron S other linear copolymers can be used. The term copolymers is intended to include polymers of two or more copolymerizable materials, i.e. it is generic to terpolymers, tetrapolymers, etc. These copolymers can be prepared as stated from combinations of hydroxyethyl methacrylate mono mer with the monomers of hydroxypropyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, butyl acrylate, t-butylaminoethyl methacrylate, diethylaminoethyl rnethacrylate, methacrylic acid, acrylic acid, itaconic acid, diacetone acrylamide, etc.
A copolymer prepared from 50% hydroxyethyl methacrylate and 50% methyl methacrylate was pulverized to 270 to 325 mesh, 10 grams of the powder charged into a six ounce aerosol can and sealed with a codispensing valve and bag assembly. The bag chamber was charged with a mixture of 4 grams of propylene glycol, 4 grams of triacetin and 32 grams of Freon 12. The resulting spray gave a skin coating around a wound similar to those set forth in Examples 2-7.
Example 8 was repeated using a terpolymer of 50% hydroxypropyl methacrylate, 10% methacrylic acid and 40% diacetone acrylamide with similar results.
Furthermore medicinally active ingredients such as germicides, fungicides, antibiotics, steroids, local anesthetics or the like may be utilized by having the medicinally active ingredient suspended or entrapped in the polymer, or if desired dissolved in the liquid phase of the system. Examples of such medicinally active ingredients include benzocaine, xylocaine, aspirin, sodium omadine (a derivative of 1-hydroxypyridine-Z-thione), hexachlorophene, bacitracin, cortisone, trimethyl benzyl ammonium chloride, cetyl pyridinium chloride, penicillin, Aureomycin (chlorotetracycline), chlorornycetin (chloromphenicol), merthiolate, sulfanilamide, sulfathiaozole, sulfaguanidine, sulfapyridine, salicylic acid, Griseofulvin, undecylenic acid, zinc undecylenate, tetracycline, hydroxytetracycline (Terramycin), dienestrol, ethynyl estradiol, diethyl stilbesterol, estradiol, myltestosterone, progesterone, ascorbic acid.
SUSPENSION OF MEDICALLY ACTIVE INGREDIENTS Example 9 To illustrate use of the invention with a fungicide, a six ounce aerosol can was charged with 9.98 grams of Hydron S powder, 270 to 325 mesh in which was dispersed 0.02 gram of sodium omadine. The can was sealed with a co-dispensing valve and bag assembly. The bag chamber was then charged with a mixture of 8 grams of polyethylene glycol 300 (polyethylene glycol having an average molecular weight of about 300) and 32 grams of Freon 12. The resulting film formed by spraying upon a colony of fungus (Aspergillus niger) showed marked depression of colony growth. The formulation was also sprayed on the skin around a wound to form a bandage.
Example 10 Example 9 was repeated using 9.7 grams of a 50-50 copolymer of hydroxypropyl methacrylate with methoxyethyl methacrylate and having 0.3 gram of hexachlorophene (a germicide) dispersed throughout the finely divided copolymer. The resulting film showed good suppression upon a colony of Salmonella typhosa. A spray on bandage was also prepared over a wound on the scalp.
Example 11 The procedure of Example 10 was repeated replacing the hexachlorophene by 0.3 gram of Bacitracin (or antiseptic). The film formed on spraying showed good suppression upon a colony growth of streptococci. A spray on bandage was also produced on skin on the cheek.
Example 12 The procedure of Example 10 was repeated replacing the hexachlorophene by 0.3 gram of cortisone. When the spray on bandage was formed on the skin good antiinflarnmatory effect upon the skin was noted.
Example 13 The procedure of Example 10 was repeated using 0.3 gram of Benzocaine (ethyl aminobenzoate, a local anesthetic) in place of the hexachlorophene. The resulting film showed good pain suppressing qualities upon abraded skin.
Example 14 Any medically active ingredient that is soluble in ethanol or an ethanol-water mixture can be put into solution with Hydron S or other hydroxyethyl or hydroxypropyl methacrylate polymers. Such solutions are then dried to a solid by any method known to the art, e.g. tray drying, roller drying, vacuum drying, spray drying, and then reduced to sprayable power form to produce an entrapped medically active ingredient.
For example, 9.0 grams of Hydron S plus 1 gram of Benzocaine were dissolved in 30 cc. of 95% ethanol. The solution was vacuum dried and the resulting polymer mix was pulverized to 270 to 325 mesh. This polymer mix was charged into an aerosol can as described in Examples l and 13. Upon spraying to form a bandage, the final film produced on the skin showed the same pain suppressing qualities as in Example 13 above.
Example 15 If the medically active ingredient is soluble in the liquid phase of the system, it can be dissolved in that phase with results similar to those described in Examples 9-14.
For example a six ounce aerosol can was charged with 9.7 grams of Hydron S, 220 to -325 mesh and sealed with a codispensing valve and bag assembly. The bag chamber was then charged with a solution of 8 grams of propylene glycol containing 0.3 gram of hexachlorophene and 32 grams of Freon 12. The sprayed film produced the same suppression of a Salmonella typosa colony as in Example 10. A satisfactory spray-on bandage was also produced on skin having a wound therein.
Obviously the medicinally active ingredient can be added to both the polymer and the plastisol forming solvent or plasticizer.
What is claimed is:
1. In a method of forming a powdery bandage in situ on skin having a wound therein which is readily removable therefrom after soaking, the improvement comprising the steps of (a) applying, as a powder, a hydrophilic water insoluble hydroxy or lower alkoxy lower alkyl acrylate or methacrylate polymer or a copolymer of 20 to 70% of a lower acrylate or methacrylate and 80 to 30% of acrylamide, methacrylamide, N-lower alkyl acrylamide or methacrylamide, or N-vinylpyrrolidone as a powder and (b) applying, simultaneously or in succession, a high boiling liquid plasticizer or solvent therefor which does not cause a burning or stinging sensation when applied on the skin and wound to form a plastisol film on the skin resulting from adherence of the powder to the wound area wet with the non-stinging plasticizer-solvent thereby covering said wound wherein the polymer powder and plasticizer are sprayed from separate containers in succession, or wherein the polymer powder and plasticizer are simultaneously sprayed from separate chambers in a single container, or wherein the polymer powder and plasticizer are sprayed simultaneously from the same chamber in a single container, the plasticizer and polymer powder being kept separate by the propellant which prevents solvation and agglomeration of the polymer powder by the plasticizer.
2. A method according to claim 1 wherein the polymer is in finely divided form substantially uncrosslinked and has a moisture vapor permeability of at least 200 grams/ sq. meter/24 hours/mil and the application is accomplished by spraying as an aerosol with the aid of a propellant.
3. A method according to claim 2 wherein the polymer has a moisture vapor permeability of at least 500 grams/ sq. meter/24 hours/mil.
4. A method according to claim 2 wherein there is included an effective amount of a medicinally active antiseptic germicide fungicide or antibiotic, local anaesthetic and/or anti-inflammatory steroid ingredient in at least one of said polymer and said plasticizer, said incorporated medically active ingredients diffusing from the film to the wound area over extended periods of time, thereby keeping the wound area free from infection, infiammation, or providing local anesthesia or analgesia.
5. A method according to claim 2 wherein the polymer powder and plasticizer are sprayed from separate containers in succession.
6. A method according to claim 2 wherein the polymer and plasticizer are simultaneously sprayed from separate chambers in a single container.
7. A method according to claim 2 wherein the polymer powder and plasticizer are sprayed simultaneously from the same chamber in a single container, the plasticizer and polymer powder being kept separate by the propellant which prevents solvation and agglomeration of the polymer powder by the plasticizer prior to spraying.
8. A method according to claim 2 wherein the polymer is selected from the group consisting of polymers of hydroxy lower alkyl acrylates, hydroxy lower alkyl methacrylates.
9. A method according to claim 8 wherein the lower alkyl group has 2 to 3 carbon atoms.
10. A method according to claim 9 wherein the polymer is essentially a homopolymer of hydroxyethyl methacrylate.
11. A method according to claim 9 wherein the polymer is a copolymer of the hydroxy lower alkyl acrylate or methacrylate with each other or with up to 50% of a lower alkyl acrylate or methacrylate, a hydroxy lower alkoxy lower alkyl acrylate or methacrylate, acrylamide, methacrylarnide, N-lower alkyl acrylamides and methacrylamides, lower alkoxy lower alkyl acrylates and methacrylates, diacetone acrylamide, diacetone methacrylamide, N-vinyl pyrrolidone or polymerizable amino substituted mono ethylenically unsaturated monomer.
12. A method according to claim 11 wherein the hydroxy lower alkyl acrylate or methacrylate is hydroxyethyl methacrylate.
13. A method according to claim 11 wherein there is also included in the polymerizable monomers an unsubstituted ethylenically unsaturated carboxylic acid in an amount up to 15%.
14. A method according to claim 9 wherein there is also included in the polymerizable monomers an ethylenically unsaturated carboxylic acid in an amount up to 15% 15. A method according to claim 14 wherein the acid is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid.
16. A method according to claim 2 wherein the polymer is a copolymer of 20 to 70% of a lower alkyl acrylate or methacrylate and to 30% of a lower alkoxy lower alkyl acrylate or methacrylate, acrylamide, methacrylamide, N-lower alkyl acrylamides and methacrylamides, or N-vinyl pyrrolidone.
17. A method according to claim 1 wherein the bandage has a thickness of about 10 mils.
References Cited UNITED STATES PATENTS Brown et a]. 424-81 Leader 424-81 Gallienne et al. 424-81 Wichterle et a] 18-58 Maeder 424-81 Wichterle et a1. 18-58 10 3,269,903 8/1966 Van Fieandt et a1. 424-81 3,400,890 9/1968 Gould 239-36 3,428,043 2/1969 Shepherd 128-268 3,483,870 12/1969 Coover et a1 128-334 5 SHEP K. ROSE, Primary Examiner US. Cl. X.R.
424-28, 32, 33, 45, 7s, 80, 81; 12s s2, 114, 155, 156, 172, 260, 265,268, 334, 335.5