US3888247A

US3888247A - First aid bandage

Info

Publication number: US3888247A
Application number: US404890A
Authority: US
Inventors: Carl B Stenvall
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1973-10-10
Filing date: 1973-10-10
Publication date: 1975-06-10
Anticipated expiration: 1992-06-10
Also published as: DK134216C; DE2448664A1; FR2247197A1; GB1494643A; DK514374A; AU7413174A; SE7412268L; JPS5825461B2; CA1048363A; DE2448664B2; JPS5065091A; SE415445B; FR2247197B1; DK134216B

Abstract

A first aid bandage is disclosed comprising a flexible backing, preferably microporous, having an adhesive layer applied thereover with an absorbent pad covering an intermediate portion of said backing and secured thereto by said adhesive layer and a strip of microporous breathable surgical tape superposed over said absorbent pad and lightly adhered to the adhesive of said flexible backing while having its adhesive surface exposed such that the entire surface of the first aid bandage is adhered to a wound site.

Description

United States Patent Stenvall 1 June 10, 1975 [54] FIRST AID BANDAGE 3,521,631 7/1970 Gardner et al 128/156 [75] Inventor. Carl B. Stenvall, Portchester, NY. Primary Examiner-Aldrich F Medbery 1 Assigneer Minnesota Mining and Attorney, Agent, or Firm-Alexander, Sell, Steldt &

Manufacturing Company, St. Paul, D L H m Minnv [22] Filed: Oct. 10, 1973 [57] ABSTRACT 21 App| 404,391) A first aid bandage is disclosed comprising a flexible backing, preferably microporous, having an adhesive layer applied thereover with an absorbent pad cover- [52] [1.8. CI 128/155; 128/156 ing an intermediam portion of said backing and [5 i] Ilrl. A6 Afilf 13/00 cured thereto Said adhesive layer and a Strip of [58] Fleld of Search [561334 335 croporous breathable surgical tape superposed over said absorbent pad and lightly adhered to the adhesive Reierences and of said flexible backing while having its adhesive sur- UNITED STATES PATENTS face exposed such that the entire surface of the first 2 838178 5/1958 Barr 123 155 aid bandage is dhered o a wo i 3 431l,3'1l 4/1969 Fischer ct all 128/156 7 CI 4 D F. 1520.306 7/1970 Gardner et a1 128/335 films guns FIRST AID BAN DAGE BACKGROUND OF THE INVENTION First aid bandages of the type wherein a pad of soft absorbent material is laid over a wound and held in place by a backing of adhesive tape are well known. Although many modifications have been made in these first aid bandages such as utilizing plastic backings for greater comformability, perforations for increased air flow, better adhering adhesives and coloring of the backing to approximate skin tones, none of the modifications has been especially directed to promote wound healing or to the reduction of disfiguring scar formation.

SUMMARY OF THE INVENTION The present invention is directed to a first aid bandage which promotes faster healing of wounds with a marked decrease or elimination of scar formation. The first aid bandage of the invention comprises a flexible adhesively coated backing having an absorbent pad secured thereto and a strip of microporous breathable surgical tape superposed thereover and being lightly adhered to the adhesive of said flexible backing around its peripheral surface, the exposed surface of said surgical tape being covered with adhesive for adhering to the skin of the user. In use, the first aid bandage is applied to a wound site in the conventional manner by grasping the ends of the bandage and stretching it over the wound. In applying the bandage, the wound edges are pulled into approximation and the microporous breathable surgical tape strip is applied directly over the wound thus maintaining the approximated position of the wound edges without interfering with proper ventilation and/or drainage of the wound. Upon cessation of bleeding and exudation, which normally occurs in a clay or less, the flexible backing and absorbent pad is removed from the wound site without disturbing the originally lightly adhered microporous breathable surgical tape strip which is left in contact with the wound until healing has been effected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of a first aid bandage of the invention;

FIG. 2 is a sectional view of the bandage of FIG. 1, with dimensions exaggerated to show details more clearly;

FIG. 3 is a sectional view of the bandage as applied to a wound; and

FIG. 4 is a sectional view of the bandage after bleeding and exudation have ceased and showing the back ing and absorbent pad being removed from the wound site.

DETAILED DESCRIPTION OF THE INVENTION The first aid bandage of the present invention comprises a microporous flexible backing 11 having a layer of adhesive I2 to the central portion of which an absorbent pad 13 is adherently secured, all as is common in the prior art. Additionally, in accordance with the present invention, a strip of microporous breathable surgical tape 14 is superposed over the absorbent pad 13 and is lightly adherently secured to the adhesive 12 of said flexible backing II. The adhesive 15 of mi croporous breathable surgical tape strip 14 is outwardly exposed so that in use. the entire skin-facing surface of first aid bandage 10 which is applied over a wound site W is adhesive. First aid bandage 10 would be provided with suitable adhesive protective cover sheet or sheets (not shown) as is customary for such bandages and a protective outer wrap (also not shown) to insure sterility.

As exemplified in the drawings, flexible backing II comprises a microporous polyurethane film produced by stretch orienting a calcium carbonate filled polyurethane film thus causing the originally filled nonporous unoriented film to become microporous. Films thus produced have been found to have a thickness of about 5 mils with pores ranging in diameter from I to 20 microns, with an average pore size of 15 microns. The films were found to have porosity values adequate to keep the underlying skin area free from maceration. having yielded Gurley Densometer values of 30 to 40 seconds per 50 cc. of air. Additionally, as shown in the drawings, flexible backing 11 is provided with die cut apertures 16 to provide for increased ventilation.

Adhesive layer 12 is an acrylate pressure-sensitive adhesive of the type described in Ulrichs US. Pat. No. 2,884,126, being a pure rubbery copolymer of isoctyl acrylate and acrylic acid in a 94:6 ratio, tackified by the addition of 40 percent of a highly stabilized ester resin tackifier, commercially available from Hercules Chemical Co. under the trade name Foral 85. This adhesive is coated onto flexible backing II in a coating weight of 7.5 grains/4 X 6 inches.

Absorbent pad 13 is formed from an airlaid web of rayon fibers having a ream weight of lbs/ream, to which has been laminated a 34; mil porous polyethylene film generally as described in Eldredge and Petters US. Pat. No. 3,285,245.

Microporous breathable surgical tape strip 14 is a tape produced in accordance with Copelands US. Pat. No. 3,121,02l, utilizing the same tackified adhesive set forth hereinabove in a coating weight of 8.5 grains/4 X 6 inches and a silicone low adhesion backsize coating in place of the urethane (carbarnate) copolymer backsize coating utilized by Copeland. This backsize coating is imperceptibly thin but provides a fibrous back surface having a reduced adhesion to the pressuresensitive adhesive layer 12. The light adhesion is, however, sufficient to permit of adequate adhesion between microporous breathable surgical tape 14 and flexible backing 11 to provide a unitary first aid bandage 10 until it is desired to separate surgical tape 14 from the bandage, i.e., strip backing 11 and pad 13 from wound site W.

It will be appreciated that the limits of force necessary to preferentially remove flexible backing II and absorbent pad 13 from microporous breathable surgical tape 14 are dependent on the degree of adhesion of surgical tape 14 to the underlying skin and the degree of adhesion of surgical tape 14 to flexible backing 11. It has been found that an adhesion difference of 10 grams/inch width will allow preferential removal of flexible backing ll and pad 13 from wound site W while leaving microporous breathable surgical tape 14 undisturbed for removal after healing has been substantially advanced.

Typical adhesion values between the components of first aid bandage l0 and of flexible backing 11 and microporous breathable surgical tape 14 to skin were as follows:

Adhesion in g./in. Width at (1 hrs. 24 hrs.

Tape 14 to skin 67.5 I591) Backing ll to Tape 14 99.0 99.0 Backing l l to skin 47.0 114.0

Although not wishing to be bound by any theory or basis for the effectiveness offirst aid bandage 10 in promoting healing of wounds, the following is offered as a possible explanation of its extreme effectiveness. The initial stage of wound healing is bleeding. One of the many functions of blood is to act as a natural seal over wounds, i.e., to act as a temporary skin while new skin is being regenerated. Blood and exuded plasma normally clots upon contact with air and forms a scab or protective seal which not only protects the wound from invasion by microorganisms but also maintains the proper environment for healing. The importance of this proper environment under the scab cannot be overemphasized. The scab not only provides a barrier to entrance by micro-organisms but probably more importantly, it functions as a semi-permeable membrane under which is provided the correct oxygen and mois ture concentration for healing.

A first aid dressing or bandage should, to be most effective, augment the healing process. Unfortunately, known first aid bandages usually applied an absorbent pad directly over the wound which would soak up the blood and other wound exudates and retain it until sufficient contact with air caused or allowed clotting, the absorbent pad then being an integral part of the clot or scab. A serious disadvantage was the fact that this reinforced clot or scab was unnecessarily thick so that it reduced diffusion of necesssary air to the wound and thus delayed the healing process. This reinforced clot or scab also interferred with diffusion of moisture vapor from the healing site. Under excessively high humidity conditions, the few contaminating micro-organisms normally present on the skin can multiply at a phenomenal rate changing the environment under the clot from a healing situation to an infection situation.

Most first aid bandages known to the art are removed prematurely because of their soiled appearance. This is a serious disadvantage because the blood clot or scab is removed along with the bandage thereby delaying the healing process. When the scab is thus prematurely removed. the growing derma cells are suddenly placed in a hostile environment, dry out and form eschar in an attempt to again seal off the wound site.

As hereinbefore noted, the first aid dressing of the present invention has an underlying relatively nonelastic. microporous tape 14 having a microporous adhesive surface adapted for direct contact with the wound. Tape 14 is hydrophobic" such that it is not readily soiled by blood and the blood clot does not adhere thereto. lt is desirable that tape 14 be short not only for esthetic reasons and for healing purposes but also for comfort since an inelastic bandage adhesively applied to the skin, if not short, tends to feel taut and uncomfortable because of its lack of comformability. Such a short length of tape would be cumbersome to apply accurately; however, being adhesively fixed to the relatively long flexible backing ll of dressing 10, the act of applying first aid dressing in the conventional manner automatically causes correct application of tape 14 over the wound site W. Once the composite first aid dressing 10 is in place over the wound site W, blood and other exudates from the wound may pass through the short microporous tape 14 into absorbent pad 13 and into or through flexible backing 11. Microporous breathable surgical tape 14 has been found to reduce bleeding somewhat more effectively than other first aid dressings known to the art and in so reducing bleeding allows the blood and exudate to clot more quickly and also reduces the need for absorbent capacity in pad 13. Indeed, this latter feature permits the use of a first aid bandage 10 having no absorbent pad 13 especially where the underlying wound is a minor laceration. In this instance the microporous breathable surgical tape 14 functions mainly as a suture" strip.

After sufficient time has elapsed to allow for cessation of bleeding and for clotting to occur, backing H and pad 13 of the dressing can be stripped away leaving only the short breathable microporous surgical tape 14 adhered over the wound. As noted the adhesive bond between backking 11 and tape 14 is designed to be less than the adhesive bond between tape 14 and the skin, so that removal of backing l] and pad 13 does not dis turb tape 14. The short microporous breathable surgical tape 14 is then allowed to remain in place over the wound until healing is substantially advanced, serving as a protective cover over the wound against microorganisms and providing beneficial entrance of oxygen and moisture concentration for healing.

in the case of an incised wound, it is known that such wounds should be drawn closed and the opposing edges held in fixed approximation to each other during and throughout the healing process. For larger or more traumatic incised wounds, it has been customary to sew or suture the wound edges together to immobilize the wound during healing. Unfortunately, suturing a wound requires considerable expertise which is not normally available during a first aid circumstance. With the first aid dressing 10 of the present invention and its totally adhesive skin facing surface, short relatively inelastic breathable microporous surgical tape 14 functions in the manner of sutures with equivalent to superior results. Not only does tape 14 approximate and immobi lize the incised wound edges but it also holds the edges in better relationship than does suturing by eliminating the gaps which occur between stitches and hence causes less cosmetic scar formation. An elastic tape cannot maintain the fixed immobility between opposing wound edges. Nor can this immobility be maintained by having the adhesive attachment remotely located from the wound as is the case with conventional first aid bandages known to the art especially during the normal flexure of the skin during movement of the portion of the body to which the bandage or dressing is applied.

It will be at once apparent that first aid bandage 10 may be fabricated with a large variety of materials provided only that the resultant first aid bandage is provided with an inner wound contacting strip 14 which is capable of providing an adequate supply of air to the wound (breathability) and permit the passage of blood and exudate therethrough. and wherein the strip 14 is releasably adhered to backing ll. Thus, first aid ban dages according to the invention have been produced utilizing other acrylate adhesives, adhesives based on urethane latices and conventional zinc oxide adhesives for adhesive layer 12 only; materials for flexible backing 11 have included films of polyurethane, vinyl, ethylene vinyl acetate, acetate, polyethylene, polyester and nylon and nonwoven materials comprised of dacron. rayon. acetate, nylon, cellulosic materials and mixtures thereof as well as woven fabrics including those conventionally used for first aid bandages; the materials for strip 14 have included nonwoven materials comprised of dacron, rayon, acetate, nylon, cellulosic materials and mixtures thereof; and absorbent pad 13 has been constructed of a variety of absorbent materials including cotton, rayon, dacron or similar absorbing material and of textile materials as is common in the first aid bandage art for absorbing blood and exudates.

While the first aid bandage has been shown as being rectangular in shape, having dimensions of about 3 by 34 inch, with an absorbent pad 13 measuring about 1% by inch and a microporous breathable surgical tape strip 14 measuring about 74 by 1 inch, it will be obvious that the first aid dressing 10 may be fabricated in various other shapes with the components thereof having a variety of dimensions, the only requirement being that the microporous breathable surgical tape 14 be releasably adhesively adhered to the backing strip.

I claim:

1. A first aid bandage comprising a first flexible adhesively coated sheet having an absorbent pad centrally adhesively secured thereto and a second flexible adhesively coated sheet superposed over said absorbent pad and being lightly releasably adhered to the adhesive of said first sheet, the adhesively coated surface of said second sheet being disposed in the same direction as the adhesively coated surface of said first sheet such that the entire surface of the first aid bandage is adhered to a wound in use.

2. A first aid bandage according to claim 1 wherein said first flexible sheet comprises a microporous film.

3. A first aid bandage according to claim I wherein said first flexible sheet comprises an oriented microporous urethane film having a thickness of about 5 mils.

4. A first aid bandage according to claim 1 wherein said second flexible sheet comprises a nonwoven web of interlaced fibers unified by a fiber-binding sizing agent.

5. A first aid bandage according to claim I wherein said adhesive coating of said first and second flexible sheets is a pressure-sensitive adhesive polymer of a nature that is relatively nonirritating to the human skin.

6. A first aid bandage according to claim 5 wherein said adhesive coating consists solely of a waterinsoluble visco-elastic pressure-sensitive acrylate polymer tackified with a highly stabilized ester resin tackifier.

7. A first aid bandage comprising a first flexible adhesively coated sheet and a second flexible adhesively coated sheet centrally superposed over said first sheet and being lightly releasably adhered to the adhesive of said first sheet, the adhesively coated surface of said second sheet being disposed in the same direction as the adhesively coated surface of said first sheet such that the entire surface of the first aid bandage is adhered to a wound in use.

Claims

3. A first aid bandage according to claim 1 wherein said first flexible sheet comprises an oriented microporous urethane film having a thickness of about 5 mils.

5. A first aid bandage according to claim 1 wherein said adhesive coating of said first and second flexible sheets is a pressure-sensitive adhesive polymer of a nature that is relatively nonirritating to the human skin.

6. A first aid bandage according to claim 5 wherein said adhesive coating consists solely of a water-insoluble visco-elastic pressure-sensitive acrylate polymer tackified with a highly stabilized ester resin tackifier.