Heat sterilizable elastic
US 2734503 A
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Feb. 14, 1956 I DOYLE 2,734,503
HEAT STERILIZABLE ELASTIC FILM BACKED BANDAGE Filed Aug. 9, 1952 INVENTOR.
BY Jafn '17. (15% United States PatentO amen I-IEAT- S TERILIZ ABLE ELASTIC NDAG .2 m D Pseri ld, i l-i stt eq t Th K ndall i' n Boston, M sai a w rarsn e 9 M chusetts Application August 1952 Ser al 3 9?;52
12 Claims. (Cl. 128- 156) This invention is concerned with sterilizable, and sterilized, adhesive ready-to-apply bandages of the type comprising a pad dressing and an adhesive backing strip. Theinvention is concerned particularly with such bandsee ha lat l anno t d but" eas atta hable p ymer c el i tast n Elastic bandages of the woven elastic thread type of the over-twist thread type have been utilized from time to time to provide bandages having elasticity of a' b b t e e b e ha e'b w 't nsafiif fq v bea e o t r b k ne a be-s t he so n be ame dirty, wet and stained. The provision of a comparatively taw bandage n e si ile 9 suited Whisk has an elastic character sufii ciently low modulus as to be almost like a second shin has long been a goal of e r ea ba da e i dl 'st B atles-e w th a c P a fi m b ing ul ap a t amide e answer which the industry was seel ting. Unfortunately,
hi her he e h h s o g n ifi9lti i iis a $99 2 fi ms a he ve anda es- In t e it at re dv ta adhesi nda e e u by e ood and rag mit et t6 i v a Wr p d nd Ste le Bse us h the means universally used jfor positive after ch ing te liza t i e able. f a ble t at sash po itive m ns be t ze in st ili n e P a t e r a taapply bandages. llp until bandages ade in accordance h t i n an' e imm r l; fi s er sterilized bandages were commercially available because of no practical solution of inherent difiiculties which reuse un i h l isto tis a id de ete ous ha ehem cal hange suc banda e sinus anta in er.- Pa nts w teri iza n t m erat r It is the object of this invention to proyide bandages comprising dressing material adhered to elastically conformable but substantially undistorted polymeric film backed adhesive tapes having low modulus (within the range of from 1090 to 2400 pounds per square inch of cross sectional area) at 100% elongation, which after manufacture may be subjected to ordinary heat-sterilization temperatures without appreciable distortion or change in dimensions and without substantial'physicochemical deterioration.
The invention is illustrated in the accompanying drawings, n which: c
Figure l a plan view in perspective of a sterilized bandage in anenvelope, 1 i I Figure 2 is a plan view in perspective of a bandage after removal ofthe wrapper,
Fig re 3 is a perspective view showing the. adhesive protective covering being removed, and I Figure ,4 is a perspective .view showing the bandage applied over a knuckle. 7 Referring to Figures 1, 2,3 and 4, thewrapped sterilized bandage 10 indicates the condition of the bandagc' when received by a purchaser. After removal of the .wrapper or Vinyl 'chlcride vi'nyl acetate copolymers 2,734,503 at nt d Feb.- 14; 9 6
an adherent pressure-sensitive adhesive 20, a superimposed adherent pad dressing 2 2" and adhesive protective strips 24 nd 26; A turned back portion 28 of strip 26 fa ita remov of th s ps Ready-to apply'bandages have as a common feature protective coverings for the pressure-sensitive adhesive such as 24 and 26. These coverings which are generally of crinoline, or some other flexible sheet material relatively easily separated from the adhesive, are usually applied as a final step prior. to cutting individual bandages'from a web;
As has been indicated, one of the difiiculties which has confronted elastic plastic bandage entrepreneurs has been unsightly distortion of bandages by sterilization. I have discovered that the distortion in bandages brought about during heat-sterilization is due" to shrinkage of the film in one dimension (with accompanying slight expansion thereof in another dimension) while the film is adherent to the protective covering 'whi'ch lattershrinks either none at all or in a different degree or direction. I have further discovered that 'such'heat-initiated alterations in dimension are largely reversions approaching in degree the changes from the original dimensions caused by'stretching the film in themachine direction during processing. I have found that by adhering only substantially unstretched or relaxed adhesive tape to the protective covering, the distortion due to shrinkage inay be' eliminated for all practical purposes. i
A second 'difliculty which has confronted those who would provide h'eat sterilize d bandages having low modulus at elongation, has been the practical attainment of sufiiciently low tensile-stress inbackings capable of physically withstanding sterilization temperatures. 1 have discovered that there exist three possibilities for such backings, having melting points above sterilization temperatures, namely: high molecular weight internally;pla sticized polymeric films; high molecular" weight pol mer films plasticized with molecular wcightpolymrs of the same monomer; and high molecular weight polymer films plasticizedwith polymers of othermon'oi ners. The employment of non-polymeric plasticizers (examples of which are given incolumn 4, lines 13 "to 2I)'universally used to reduce the modulus of elasticity incrdinary films must'be carefully limited, as hereinafter explained, when adhesives are used with films intended for bandages which are to undergo heat-sterilization. i
0f the internally plasticized group of possible backings I have found the following to be satisfactory to produce the elastioplastic film bandages having low modulus at i099?) elongation, of this inventioni N- alkyl polyamides ,Chlo hated and chlorosulfonated polyethylene Polyamides containing oxo and thioxo linkages Of the group consisting of high molecular weight polymers plasticizedwith low molecular weight polymers of the same monomer, films of polymerized tetrafluorethylone and polymerized trifiuoromonochloroethylene are examples of those suitable for the bandages of this invention. v v.
The third group, which I consider most suitable for bandage backing materials of this 'inventionfconsis'ts of high molecular weight polymers and c'opolyrne'rjs plasticized with polymeric plasticizers ofdifferent monomers In group are:
than the polymer plasticized. Polymerized vinyl chloride polymerized vinylidene chloride Polymerized vinyl fluoride Pol'ymerized vinylidene fluoride 'Yinyl' chloride-acrylonitrile copolymers Chlorinated p'oly rne'n'zed' "ethylene Vinyl chloride-vinylidene chloride copolymers Vinyl chloride-vinyl acetate and vinylidene chloride terpolymers Vinylidene chloride-vinyl acetate copolymers Polyvinyl alcohol cross-linked with hexamethylene diisocyanate or other cross-linking agents Polyurethanes such as that obtained by interaction of polyethylene glycols and hexamethyl diisocyanate and Elastic cellulose ethers In polymers of monomers including vinyl acetate, the latter should not be used in excess of of the total monomer weight.
A third difficulty, which has not been fully appreciated by some manufacturers of plastic adhesive tapes having higher modulus characteristics in plastic backings, has been the possibility of physico-chemical instability brought about by interdittusion and migration of plasti cizers from and between the film and the pressure-sensitive adhesive. This problem has been known to exist even under ordinary storage conditions. Solutions have been proposed in the past but the severe effects of heatsterilization upon physico-chemical stability have not been encountered by any of the plastic tapes which heretofore have been available such as those for plastic scaling, for anticorrosion wrappings and for electrical resistance wrappings. The Oace Patent No. 2,559,990 has proposed certain plasticizers for polymeric-backed tapes containing predominately vinyl chloride but the proposed proportions of polymeric and non-polymeric plasticizers utilized are not satisfactory. for tapes having low modulus at 100% elongation which are to be subjected to sterilization temperatures. I have found that it is not enough to consider the plasticizer associated with the backing alone; the plasticizer in the pressure-sensitive adhesive must be considered as well.
In accordance with this invention I have discovered that those tapes having the greatest degree of physicochemical stability are those in which both the backing and the adhesive are completely free of non-polymeric type plasticizers. Backings of the third group indicated above may be effectively plasticized to low modulus at 100% elongation solely with from 25 to 40% based 011 the weight of the backing of one of the modified or unmodified polymerized condensation products of a polyhydric alcohol and a polybasic acid or with acrylonitrile rubbers. Examples of the former are the viscous alkyd resins which are mixtures of oil-modifiedpolyesters of sebacic acid and other polybasic acids sold under the designation, Paraplex Resins, by the Resinous Products and Chemical Company, Philadelphia, Pa. These resins may presently be purchased in four molecular species by the designations 6-25, G-40, G-50 and G-60. Other plasticizers in this general group are the polyglycol azelates sold under the trade name Plastolein 9715 and X-960-R by Emery Industries Inc., Cincinnati, Ohio, the polyethylene sebacate-azelates sold under the trade name Harflex 500 by the Hardesty Chemical Co. Inc., New York, N. Y., and the polyesters sold by The General Electric Company of Pittsfield, Mass., under the designations 2557 and 2559.
Of the group of acrylonitrile rubbers suitable as plasticizers, examples are the butadiene-acrylonitrile copolymers sold under the trade name, Hycar, by the B. F. Goodrich Chemical Co., Cleveland, Ohio, and under the trade name Paracril by the Naugatuck Division of the U. S. Rubber Company, New York, N. Y.
While plastic elastic adhesive tapes preferred for the bandages of this invention attain the greatest degree of physico-chemical stability when only polymeric plasticizers are used in both the adhesive and the backing, I have obtained acceptable results when an amount of non-polymeric plasticizer not more than of the order of 3% of the total weight of the backing and adhesive is utilized where the ratio between adhesive weight to the total weight varies from to 40%. Such small amounts of non-polymeric plasticizer appear insutficient to materially change the optimum characteristics of the tape during or after heat-sterilization. It is immaterial also whether this amount of non-polymeric plasticizer be utilized all in the plastic back, all in the adhesive or divided. Very probably such non-polymeric plasticizers seek a balance eventually regardless of where they are initially placed.-
Of the non-polymeric type plasticizers suitable for the tapes of the bandages of this invention to the extent of the order of 3% of the weight of the backing and adhesive, the following are examples:
Dioctyl phthalate Butyl benzoyl benzyl phthalate Dioctyl sebacate Di-Z-ethylhexyl adipate Ethylene diabietate Octyl diphenyl phosphate Methyl Cellosolve ricinoleate Trioctyl phosphate Opaque or filled film backings are preferred for the bandages of this invention but transparent unfilled films with transparent or opaque adhesives are entirely satisfactory.
In general, fillers useful in rubber compounding may be used in the backings of this invention with the possible exception of certain amphoteric and alkaline earth oxides, especially zinc oxide, which appears to have some detrimental effect especially upon the vinyl chloride and vinylidene chloride backings of this invention. The preferred filler for the backings in products of this invention is titanium dioxide. Other recommended fillers are hydrated silica, precipitated silica, alumina hydrate, calcium silicate, magnesium silicate, whiting and carbon black.
All of the vinyl chloride and vinylidene chloride polymers useful in the products of this invention should be stabilized by methods well known in the vinyl film industry. Stabilizers which are useful for protection against the deteriorating effects of heat and light are barium ricinoleate, cadmium ricinoleate, barium 2- ethylhexoate, cadmium 2-ethylhexoate, dibutyl tin dilaurate, dibutyl tin maleate, dibutyl tin oxide, dibutyl di phenyl tin, bisglycidyl tin dilaurate, strontium ureate, strontium naphthenate, dioctyl pyrophosphate, polymerized alkyl phenoxy epoxides, and glycidyl phenyl ether.
FILMS A preferred example of the films suitable for the products of this invention was prepared from a white polyvinyl chloride organosol material in accordance with the following formula:
Example I Parts by weight An emulsion copolymer of vinyl chloride and vinyl acetate containing 93-95% vinyl chloride and having a particle size of approximately 5-10 micr n A modified polymerized condensation product of The formula was ground in a water-jacketed pebble mill for 48 hours to a point of adequate dispersion without substantial increase in viscosity.
Following deaeration and screening to remove undispersed pigment or resin particles, the organosol was metered in suitable wet thickness onto a heavy supercalendered paper by means of an adjustable floating knife of the type well known in the coating and spreading indnst'r'y. Thereafter it was passed through a multiple zoned oven increasing in temperature from approximately 125 F. to approximately 525 F. or to such temperatureas would permit adequate fusing or the polyvinyl chloride resin. After fusing, the film was one which at room temperature exhibited adequate physical charaeteristics' of tensile, elongation, modulus of elasticity, elastic recovery and tear resistance.
Another example of a preferred type of film was prepared from 'a flesh-colored organosol of polyvinyl chloride material in the samemanner as was used in preparing Example I but according to the following formula:
Example II v Parts by weight An emulsion copolymer of vinyl chloride and vinylidene chloride where the vinyl chloride A further example of a preferred type of film was prepared from a white organosol from a polymer predominately vinylidene chloride in the same manner as was used in preparing Example I from the following formula:
Example 111 Parts by weight PRIMERS Because of the relatively poor anchorage which hydrocarb'on adhesives achieve with some of the suitable backings, particularly the vinyl chloride and vinylidene 5 chloride polymer baokings, I prefer to utilize a primer to be applied to the backing prior to application of the adhesive. As my preferred primer I utilize the following:
Example I Parts by weight Latex (55% solids) of 60-65 parts monomeric vinyl chloride polymerizedwith 40-35 parts butadien acrylonitrile copolymer in 75:25 ratio 100 Latex (60% solids) of polymer of 2-chlorobutadiene r Y r v r r 100 Dispersion of condensation products of heptaldehyde and polyamines solids) 10 Methyl cellulose ether (1200 cps.) 1
Other primers satisfactory for use with vinyl chloride and vinylidene chloride backings and hydrocarbon adhesives are:
Example 11 Parts by weight Latex (55% solids) of 60-65 parts monomeric vinyl chloride polymerized with 40-35 parts butadiene-acrylonitrile copolymer in 75.25 ratio--- 100 Natural rubber latex (centrifuged) 100 Ammonium caseinate (added as solution) 1.7
films of this invention, the following are given:
Example 1 Parts by weight #1 pale crepe natural rubber 35 Dihydro abietic acid (tackifying resin) 15 Heat treated wood rosin (tackifying resin) 15 Zinc oxide 28 Polyisobutylene 2 I Age resistors 3.5 Solvents, blended hydrocarbons 150 Example II Parts by weight Polyisobutylene (high molecular weight) 15 #1 thin pale crepe natural rubber 12 0 Factice (White) -4 5 Glycerol ester of dihydroabietic acid (tackifying Ie Slll) Polyterpene resin (tackifying resin) 10 Dihydroabietic acid (tackifying resin) 5 Zinc oxide 25 Precipitated silica 3 Polyisobutylene (low molecular weight) 6 Age resistors l a 3.0 White lanolinfi 1 Solvents, blended hydIQCafbOnS ..l 150 Example III Parts by weight GR-S rubber-X496-SP 56 Pale crepe rubber 16 Precipitated hydrated silica 11 Age resistors 4.5 Synthetic beeswax 1.5 Titanium dioxide 8 Rosin, 40% polymerized 34.2 Hydrogenated rosin 34.2
butadiene 25 Morpholino abietate (10% aqueous solution) 5.0 'Carboxymethyl cellulose .5
Example V Parts by weight Latex 50% solids) of a copolymerization of methylacrylate and butylacrylate in 1:1 ratio Hydroxyethyl cellulose .5
Example VI Latex 50% solids) of a copolymerization in equal parts of vinyl chloride, acrylonitrile and ethyl acrylate In addition to the above primers, that illustrated in Example I of the Oace patent above mentioned or the primer claimed in claim 1 of the Hopkins Patent No. 2,555,745 may be utilized.
ADHESIVES As examples of adhesives preferred for the adhesive Solvents, blended hydrocarbon 250 An example of a pressure-sensitive adhesive which may be applied directly to backings of vinyl chloride and vinylidene chloride is as follows:
7 Example IV Parts by weight Copolymer of methyl acrylate-ethyl acrylate 50 Aryl toluene sulfonamide-formaldehyde polymer (tackifying resin) Terpene modified phenol formaldehyde polymer (tackifying resin) 10 Polyhydric alcohol ester of maleic modified heatisomcrized wood rosin (tackifying resin) 1O Benzoylbenzyl phthalate 3 Modified polymerized condensation polymer of dicarboyxylic acid and polyhydric alcohol l2 Precipitated silica 8 Alkylated polyhydroxyphenol 3 Mixed solvents: (xylol-80%; propanol--10%;
methylisobutyl ketone10%) 150 The above adhesives are prepared by milling the clastomers on a chilled mill for fifteen minutes, adding the tackifying resins while heating to 220-225 F. The mix is then transferred to a suitable internal mixing device such as the Baker-Perkins mixer where the remaining ingredients, with the exception of the solvent, are added and the whole mixed for fifteen minutes at 220225 F. Thereafter cooling water is circulated through the mixer jacket. The solvent blend is added slowly so as to avoid excessive loss by evaporation. When the solvent addition has been completed, the adhesive is ready for spreading.
The pad dressings of this invention may be of any conventional type or material capable of withstanding sterilization temperatures. They may be absorbent or nonabsorbent, woven or non-woven, fibrous or non-fibrous. Such diverse materials as cotton gauze, synthetic fiber gauzes, felts of cotton, wool and synthetic fibers, sponges such as rubber and synthetic polymer sponges, and algenic sponges, felts and fibrous pads are representative and suitable.
The following general procedure may be employed in producing the novel bandages of this invention:
The plastic film-forming material is spread either in the form of a solution, a plastisol, an organosol or a latex onto a heavy super-calendered paper of the type generally used for preparing cast films. The film is then dried and fused (if necesary) while adherent to the paper. If a primer anchorcoat is desired, the film is run through a reverse roll spreader where it is coated with a skim coating of a suitable primer. The primer is dried either by pasage through a short oven or by other conventional means. An adhesive, as previously described, is then applied to the backing in proper thickness by a suitable knife or reverse roll spreader. The combination then passes through an oven wherein the adhesive is dried. Upon emerging from this oven, the tape and the adherent paper are slit, as a unit, into widths corresponding to the lengths of the finished bandages. Each of the narrow widths is then led to a machine similar to that described in the Eustis Patent No. 2,029,260 wherein dressing materials are spotted onto the adhesive surface and the divided crinoline or other covering strips are applied with the fold-over running lengthwise. At this point the paper carrier-surface is separated from the bandage material, the paper carrier being used to intermittently pull projecting portions of the bandage material out beneath a cut-off knife which severs the bandage strip into successive individual bandages by cutting through the entire bandage strip including the crinoline coverings. The bandages are then wrapped and packaged after which they are heatsterilized.
1. A stable heat-resistantready-to-apply bandage comprising a substantially unstretched, relaxed, polymeric film backing having a low modulus at elongation, a layer of pressure-sensitive adhesive and an adherent pad dressing, said backing and adhesive together containing a total of not more than the order of 3% by weight of non-polymeric plasticizer for said backing.
2. A bandage as claimed in claim 1 wherein the band age is heat-sterilizable.
3. A bandage as claimed in claim 1 wherein the adhesive is a hydrocarbon-elastomer pressure-sensitive adhesive.
4. A bandage as claimed in claim 1 wherein the adhesive is a polymeric acrylic elastomer pressure-sensitive adhesive.
5. A bandage as claimed in claim 1 wherein the polymeric film backing includes an internally plasticized polymer.
6. A bandageas claimed in claim 1 wherein the polymeric film backing includes a polymer plasticized by a polymer of different monomeric origin.
7. A bandage as claimed in claim 1 wherein the polymeric film backing includes a polymer plasticized by a lower molecular weight polymer of the same monomeric origin.
8. A bandage as claimed in claim 1 wherein the polymeric film backing includes a polymer plasticized by a polymer of different monomeric origin derived from a condensation product of a polyhydric alcohol and a polybasic acid.
9. A bandage as claimed in claim 1 wherein the polymeric film backing includes a polymer of monomers including a major proportion of vinyl chloride plasticized by a polymer of different monomeric origin.
10. A bandage as claimed in claim 1 wherein the polymeric film backing includes a polymer of monomers including a major proportion of vinylidene chloride, plasticized by a polymer of difierent monomeric origin.
11. A bandage as claimed in claim 1 wherein the polymeric film backing and the layer of pressure-sensitive adhesive constitute a transparency.
12. A bandage as claimed in claim 1 wherein the polymeric film backing includes a polymer of monomers including a major proportion of vinyl chloride plasticized with 25 to 40% of the total weight of the backing of a polymeric plasticizer derived from a condensation product of a polyhydric alcohol and a polybasic acid.
References Cited in the file of this patent UNITED STATES PATENTS 2,029,260 Eustis et al. Jan. 28, 1936 2,484,045 Morgan Oct. 11, 1949 2,644,804 Rubin July 7, 1953 2,656,331 Sprung Oct. 20, 1953