CA1048363A

CA1048363A - First aid bandage

Info

Publication number: CA1048363A
Application number: CA74209162A
Authority: CA
Inventors: Carl B. Stenvall
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1973-10-10
Filing date: 1974-09-13
Publication date: 1979-02-13
Also published as: JPS5065091A; FR2247197A1; GB1494643A; JPS5825461B2; DE2448664A1; US3888247A; SE415445B; SE7412268L; FR2247197B1; DK134216C; DK514374A; DK134216B; DE2448664B2; AU7413174A

Abstract

ABSTRACT

A first aid bandage comprising a flexible backing, preferably microporous, having an adhesive layer applied there-over 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 being disposed in the same direction as the adhesive layer such that the entire surface of the first aid bandage is adhered to a wound site.

Description

~i`.N. 9lo~û3Ll ~33~3 First Aid Banda~e First aid bandages o~ the type wherein a pad of soft absorbent materlal is laid over a wound and held in place by a backing of adhesive tape are well known. Although many modi~ications have been made in these first aid bandages such as utiliæing plastic backings for greater con~ormability, per-forations 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 ln wound healing or to the reduction of disfiguring scar forma-tion.
The present invention is directed to a first aid bandage which promotes faster healing of wounds with a marked decrease or elimination of scar ~ormation. 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 there-over and being lightly adhered to the adhesive of' said flexl- -~ble backing around its peripheral sur~ace, the exposed surface of said surgical tape being covered wlth 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 grasp-ing the ends of the bandage and stretching it over the wound.
In applying the har~age, the wound edges are pulled in~o approximation and the microporous breathable sur~ical tape strip is applied directly over the wound thus maintaining the approximated position of the wound edges without inter-fering with proper ventilation and/or drainage of the wound.
Upon cessation o~ bleedlng and e~udation, which normally occurs in a day or less, the flexible backing and absorbent pad is removed from thc wound site without c~isturbing the originally lightly adhered microporous breathable surgical tape strip which is left in contact with the wound until healinx has been effected.
According to the broadest aspect of the invention there is provided a first aid bandage comprising a first Elexible adhesively coated sheet alld a second flexible adhesively coated sheet centrally superposed over said first sheet and being lightly releasably adhered to the adhesive oE said first sheet, the adhesively coated surEace 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.
Figure 1 is a plan view of a first aid bandage of the invention, Figure 2 is a sectional view of the bandage of Figure 1, with dimensions exaggerated to show details more clearly:
Figure 3 is a sectional view of the bandage as applied to a wound;
and Figure 4 is a sectional view oE the bandage after bleeding and exudation have ceased and showing the backing and absorbent pad being removed from the wound site.
The first aid bandage 10 of the present invention comprises a microporous flexible backing 11 having a layer of adhesive 12 to the central portion of which an absorbent pad 13 is adherently secured~ all as is common in the prior art. AdditionallyJ 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 11. The adhesive 15 of microporous 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 aclhesive.
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 si~

~ Lq~
11 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 1 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. Addi-0 tionally, 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 Ulrich's U.S. Patent No.

2,884,126~ issued December 13~ 1960, being a pure rubbery copolymer of isoctyl acrylate and acrylic acid in a 94:6 ratio, ;
tackified by the addition of 40~ 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 11 in a coating weight of 7.5 grains/4"x6"
(7.5 grains/10 cm. x 15 cm.).
- Absorbent pad 13 is formed from an airlaid web o-F
rayon fibers having a ream weight of 80 lbs/ream (36 kg/ream), to which has been laminated a 3/4 mil (.019 mm) porous poly-ethylene film generally as described in El~redge and Petters U.S. Patent 3,285,245, issued November 15, 1966.
Microporous breathable surgical tape strip 14 is a tape produced in accordance with Copeland's U.S. Patent

3,121,021 issued February 11, 1964, utilizing the same tackified adhesive set forth hereinabove in a coating weight of 8.5 grains/4" x 6" (8.5 grains (10 cm x 15 cm) and a silicone low adhesion backsize coating in place of the urethane (carbamate) copolymer backsize coating utilized by Copeland. This backsize coating is imperceptibly thin but provides a fibrous back surface having a reduced adhesion to the pressure-sensitive 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 11 and absorbent pad 13 from microporous breathable surgical tape 14 15 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 (2.5 cm) width will allow preferen-tial removal of flexible backing 11 and pad 13 from wound site W while leaving microporous breathable surgical tape 14 undis-turbed for removal after healing has been substantially advanced.
Typical adhesion values between the components of first aid bandage 10 and of flexible backing 11 and microporous :
breathable surgical tape 14 to skin were as follows:

3~

Adhesion in g./in. (g./2.54 cm) width at O hrs. 24 hrs.
Tape 14 to skin 67.5 159.0 Backing 11 to Tape 14 99.0 99~
Backing 11 to skin 47.0 114.0 Although not wishing to be bound by any theory or basis for the e~fectiveness of first aid bandage 10 in promoting healing of wounds, the following is offered as a posslble explanation o~ its extreme effectivenessO The initial stage of wound healing is bleedlngO One of the many functions o~ blood is to act as a natural seal over wounds, i.eO~ 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 whlch not only protects the wound from invasion by micro-organisms but also maintains the proper environment for healing. The importance o~ this proper environment under the scab cannot ~:
be overemphasizedO The scab not only provides a barrier to entrance by mlcro-organlsms but probably more ~mportantly, it functions as a semi-permeable membrane under which is provided the correct oxygen and moisture concentration ~or healing.
A ~irst aid dresslng or bandage should, to be most effective, augment the healing process. Un~ortunately, known first aid bandages usually applied an absorbent pad directly over the wound whlch 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 o~ the clot or scab. A serious dls-advantage was the fact that this reinforced clot or scab was unnecessarily thick so that it reduced diffusion o~

.. .

necessary air to the wound and thus delayed the healing process. Thls reinforced clot or scab also interferred with dirfusion of moisture vapor ~rom the healing site.
Under excessively high humidity conditions, the few con&
taminating micro-organisms normally present on the skin can multiply at a phenomenal rate changing the environ-ment under the clot from a healing situation to an infec-tion 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 dress-ing 10 of the present invention has an underlying relatively non-elastic, microporous tape 14 having a microporous adhe-sive 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 there-to. It 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 uncomfort-able because of its lack of conformability. Such a short length of tape would be cumbersome to apply accurately;
however, being adhesively fixed to the relatively long flexible backing 11 of dressing 10, the act of applying ~: ' ' ', ~83~3 flrst aid dressing 10 in the conventional manner auto-matically causes correct application of tape 14 over the wound site W. Once the composite first aid dress-ing 10 is in place over the wound site W, blood and other exudates from the wound may pass through the short micro-porous tape 14 lnto 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 al}ow ~or cessation of bleeding and for clotting to occur, back-ing 11 and pad 13 of the dressing can be stripped awayleaving only the short breathable microporous surgical tape 14 adhered over the wound~ As noted the adhesive bond between backing 11 and tape 14 is designed to be less than the adhesive bond between tape 14 and the skin, so that removal of backing 11 and pad 13 does not disturb 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 micro-organisms and providing bene~iclal entrance of oxygen and moisture .. ' ~ :. ;;:

33~3 concentratlon 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 rixed approximation to each other during and throughout the healing process. For larger or more traumatlc incised wounds, it has been customary to sew or suture the wound edges kogether to immobilize the wound during healing. Unfortunately, suturing a i wound requires considerable expertlse which is not nor-mally available during a first aid circumstance. Withthe first aid dressing 10 of the present invention and its totally adhesive skin facing surface, short relatiuely in-elastic breathable microporous surgical tape 14 ~unctions ; in the manner of sutures with equivalent to superlor results Not only does tape 14 approximate and immobilize the incised wound edges but it also holds the edges in better relation-ship than does suturing by eliminating the gaps which-occur between stitches and hence causes less cosmetic scar ~Qrma tion, 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 bandage~ known to the art especially during the normal flexure o~ the skin during movement of the portion o~ the body to which the bandage or dressing is appliedO
It will be at once apparent that first aid bandage 10 may be fabricated-with a large variety o~
materials provided only that the resultant ~irst aid bandage is provided with an inner wound contacting strip .

3~3 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 11. Thus, first aid bandages 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 o~ polyurethane, plasticized polyvinyl ; :~
chloride ethylene vinyl acetate copolymer, plasticized cellulose acetateJ
polyethylene, polyester and nylon and nonwoven materials comprised of 10 dacron , rayon, nylon ccllulosic 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, nylon, cellulosic materials and mixtures thereof; and absorbent pad 13 has been constructed of a variety of absorbent materials including cotton, rayon9 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 10 has been shown as being rectangular in shape, having dimensions of about 3 inches by 3/4 20 inch (7.6 cm by 1.9 cm), with an absorbent pad 13 measuring about 1/2 inch (1.27 cm) by 3/4 inch (1.27 cm x 1.9 cm) and a microporous :
breathable surgical tape strip 14 measuring about 3/4 inch by 1 inch (1.9 cm x 2.54 cm), it will be obvious that the first aid dressing 10 may be fabricated in various other * Trade Mark "~
.,. .;
- . , ~ . . . ;

3~3 shapes with the components thereof having a variety o~
dimensionsg the only requirement being that the micro-porous breathable surgical tape 14 be releasably adhesively adhered to the backing strip.

,

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

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 1 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 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.

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 sur-face 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 band-age is adhered to a wound in use.