Patent Application
20150133844
The present invention relates to adhesive articles that are easily removable from the substrate on which they are disposed. More particularly, the invention relates to adhesive articles such as medical tapes and wound covers with easy to tear regions for removal from the skin of a mammal.
Adhesive articles such as tapes and wound covering bandages are well known in the art and are used for various medical applications for humans and other mammals and for sports protection of humans. In the case of wound covering bandages, a sterile wound-covering pad contacts the wound, and a backing layer coated with a pressure sensitive adhesive provides secure attachment of the bandage to bare skin adjacent to a wound.
Recently, adhesives have been developed for adhesive articles such as bandages that do not peel off even when the bandage is wetted by sweat or swimming activity. The corners of the article are often shaped to prevent easy release of the bandage.
All these developments make removal of the bandage difficult, especially when the area of the skin is covered with hair. Bandage removal is typically so painful that most users remove the bandage by pulling sharply, as fast as possible, to minimize the duration of pain. This action sometimes causes further cuts and wounds to the user, especially when the bandages are repeatedly removed and replaced on the wound site.
When bandages are used to treat small appendages (fingers or toes), the bandage is often wrapped around the appendage, and the backing layer overlaps. In these cases, the adhesion of the overlap is stronger than the adhesion of the bandage to the skin. Frequently, to avoid pulling the bandage sharply, a user employs a sharp instrument such as a knife, scissor, or even a scalpel to assist in removing the bandage from the skin. This procedure could cut the user seriously enough to warrant stitches.
To overcome the issue of difficult removal of adhesive articles, others have used “pull-tabs”, pieces of backing with no adhesive jutting out from edges of the backing. In other cases, the backing has regions of low adhesion to help in removal from the skin. Another easy-removal method is to have solid beads containing oil that can be broken to release the oil into the adhesive region to disrupt the adhesion.
For example, Silber, U.S. Pat. No. 4,526,166, purports to disclose a bandage including first and second carrier strips. The first strip includes a liquid absorbent, soft, pad of material which is to be placed over a wound. The second strip carries an adhesive to be placed onto the patient's skin at a location spaced from the wound. The two strips have ends which are connected by a releasable attachment forming a third element such as a tear string which is easily manipulable to free the strips from one another. This enables lifting of the pad and first strip independently of the second strip, so that force applied to the second strip to free it from the skin is not transferable to the first strip and wound.
Stebbings et al., U.S. Pat. No. 7,078,582, purports to disclose pressure sensitive adhesive articles and methods, particularly stretch removable adhesive articles that are preferably for use in adhering to skin or like delicate surfaces. Preferably, stretch removability of the article occurs as a result of the selection of a stretch removable pressure sensitive adhesive. In one embodiment of the articles and methods, the adhesive and backing delaminate upon removal. In another embodiment of the articles and methods, the backing includes a predefined tab located in a central location of the backing.
These solutions have failed to completely solve the issue of difficult removal of adhesive articles. Pull tabs can accidently catch and release the article prematurely. The beads with oil can rupture accidently and release the article prematurely. And controlling the amount of adhesive in various regions of the backing is difficult.
There remains a need in the art for adhesive articles that adhere well to mammalian skin and are easily removable therefrom at will without causing excessive pain or risk of further damage. This need has been exacerbated by the inherent difficulty in creating a bandage adhesive that bonds well and, at the same time, can be readily removed with minimal difficulty during peeling of the bandage away from mammalian skin.
Surprisingly, we have found a novel way to improve the ease with which an adhesive article may be removed from a user's skin. In one aspect of the invention, an elongate adhesive article having a length substantially greater than a width, includes a backing layer having an adhesive layer and a single weakened region formed of a removable strip of backing layer that is oriented substantially perpendicular to the article length. The removable strip of backing layer is at least partially defined by a pair of lines of weakness separated by a gap of between about 2 and about 15 mm. The elongate article may include an absorbent pad in the form of an adhesive bandage or sticking plaster.
In another aspect of the invention, a method of using such an elongate article includes the steps of applying the article to the skin of a mammal, removing a strip from the article; and removing the remainder of the article from the skin. The step of removing the strip includes gripping the removable strip of backing layer proximate the first side edge of the article and pulling the removable strip of backing layer away from the skin to which it is applied, thereby fracturing the backing layer along the lines of weakness. The removable strip is then removed from the adhesive article, leaving a remainder of the adhesive article adhered to the skin.
An embodiment of this invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which
a is an enlarged portion of the elongate adhesive article of
a is an enlarged portion of the elongate adhesive article of
a-c are a representation of one removal method of the elongate adhesive article of the present invention from a user's finger.
Again, adhesive articles that adhere well to for human and other mammalian skin are often difficult to remove, especially when they are applied around fingers and toes. Therefore, we have provided novel elongate adhesive articles that are easily removable from mammalian skin without causing excessive pain or risk of further damage.
Backing layer 11 may have various shapes, including but not limited to, rectangular, oval, ovoid, or oblong. The shape of the elongate adhesive article 10 is defined by the shape of backing layer 11. Backing layer 11 may be thin, highly flexible or deformable, water-impervious, and clear or opaque. In general, the thickness of backing layer 11 is between about 0.05 to 0.2 millimeter (“mm”) to achieve the forming and flexing characteristics desired.
It is desired for the material used in backing layer 11 to be both conformable to the contours of the body, and flexible so as to permit free movement of the body part wearing the product. Further, backing layer 11 could be lightweight, and may be elastic (elastomeric) in character. It can be a woven or nonwoven fabric, a film or a foam. Polymeric materials useful in forming the backing layer 11 include polyolefin (such as polyethylene), polyurethane, and polyvinylchloride. Other examples of backings include, but are not limited to, nonwoven, woven, or knitted fabrics such as cotton, polyester, polyurethane, rayon and the like.
A polyethylene film may be used as backing layer 11, and particularly effective results can be achieved with stretchable, elastomeric films formed of polyurethane, which has the further advantage of gas (including water vapor) transmissibility. It is to be understood, however, that other flexible, water insoluble polymeric films known in the art may be used. Furthermore, backing layer 11 may be formed from closed-cell polymeric foam, particularly one with an integral skin covering the side facing away from the skin of the user. Foam layers formed of polyurethane or polyethylenes are suitable, while other polymeric foams having similar properties may be used. In addition, backing layer 11 may be made from other polyolefins, vinyl polyethylene acetate, textile non-woven fabrics, rubber, or other materials known in the adhesive article art. Polymers used to make backing layer 11 used in bandages of the present invention may exhibit viscosity of about 500 to 500,000 centipoises at temperatures of about 190° C., or about 1,000 to 30,000 centipoises at temperatures of about 190° C., or about 3,000 to 15,000 centipoises at temperatures of about 190° C. Backing layer 11 may be impermeable to liquid, but permeable to gas, which allows the wound and the skin to which the elongate adhesive article 10 of the present invention is adhered to breathe. In one embodiment, backing layer 11 may have pores of such a size that will allow only the passage of gases, which have molecules of extremely small size. Finally, one can conceive of a backing layer that is perforated for more ventilation of the skin. Perforations may be circular in area and have a range of diameters, such as from about 0.1 to about 0.8 millimeters. However, backing layer 11 may be totally impermeable to gases, when necessary.
In one preferred embodiment, the backing layer comprises a woven fabric having either a warp or weft oriented substantially across the width of the elongate article. Thus a tear propagated across the elongate article will tend to continue until the article is separated by removal of the removable strip 15. In another embodiment, the backing layer comprises an oriented polymer in which a tear propagated across the elongate article will tend to continue until the article is again separated by removal of the removable strip 15.
Again, the length of the backing layer is substantially greater than the width. Preferably, the width of backing layer 11 is at least about 10 mm, more preferably at least about 15 mm or at least about 20 mm. In a preferred embodiment, the width of backing layer 11 is less than about 100 mm, more preferably, less than about 70 mm, and most preferably, less than about 40 mm. Thus, the width of backing layer 11 may be between about 10 mm and 100 mm, preferably between about 15 mm and 70 mm, more preferably between about 20 mm and 40 mm. In one embodiment the width of backing layer 11 is about 25 mm.
Article 10 has a single weakened region 14 at least partially defined by two lines of weakness 16 which originate from first side edge 11a, and are disposed along the y-axis. The resulting removable strip has a width (defined by the maximum distance between the two lines of weakness 16) between about 2 mm and 15 mm, preferably between about 2 mm and 10 mm, more preferably between about 2 mm and 6 mm, and most preferably about 4 mm.
While
Preferably, the lines of weakness 16 are substantially parallel. However, it may be acceptable for the lines to converge or diverge as long as they provide a removable strip 15 of backing layer 11.
Weakness elements 16a may be any shape, including circular, elliptical, linear, arrow- or V-shaped, Y-shaped, S-shaped, chevron, a partial-chevron, and a dot pattern. In some embodiments, a simple linear pattern of linear cuts is used, in which the cuts are aligned to create a single, broken separation line that extends laterally across the elongate adhesive article 10.
In some embodiments, the weakness elements are of equal length. This is shown in the enlarged view if
The sizes of weakness elements 16a and the distance between them help to determine the force required to tear and remove the removable strip 15.
As shown in
Again, the backing layer 11 of the elongate adhesive article 10 has an adhesive layer associated with, preferably disposed on, the first surface thereof. In general, any of a variety of pressure-sensitive adhesives can be utilized as adhesive layer 12. In particular, pressure-sensitive adhesives that are biocompatible with human skin are typically utilized. In some embodiments, an adhesive of the present invention may also be either generally water soluble or generally insoluble, or dispersible in an aqueous environment. For instance, commercially available dispersible pressure-sensitive adhesive is sold under the trade name of HL-9415-X and is available from H.B. Fuller Company. Another suitable adhesive includes about 10-75% by weight of a polyalkyloxazoline polymer, 10-75% by weight of a functional diluent comprising a hydroxy compound or a carboxylic acid compound, and 5-50% by weight of a tackifier.
Adhesive layer 12 may comprise hydrocolloids. The hydrocolloid element used may be any substance that has a good performance in this utilization, as for example, sodium carboxymethylcellulose, pectin, xanthan gum, polysaccharides, sodium or calcium alginates, chitosan, seaweed extract (cageenan), polyaspartic acid, polyglutamic acid, hyaluronic acid or salts and derivatives thereof, among others.
Hydrocolloids, just as sodium carboxymethylcellulose and pectin, among others, are agents that form gels as soon as they come into contact with the bodily fluids from the wound. When used in adhesive bandages, these hydrocolloids are combined with elastomers and/or adhesives. Preferably, the adhesive bandage should provide a humid environment but without saturation, cicatrisation, which is a situation suitable for acceleration of the healing,
Adhesive layer 12 may be any conventional adhesive known for such use, as for example pressure acrylic adhesives, among others. Additionally, such an adhesive may contain a resin for increasing adhesion, a cohesion increasing agent, an absorption agent (preferably a polyacrylate superabsorbent, a polyacrylate salt superabsorbent or a mixture thereof), a plasticizer and optionally a pigment. The adhesive layer may further be configured in discontinuous patterns, arranged in lines, screen, spray or any other which a person skilled in the art understands as discontinuous, composed by an elastomeric base.
To aid in the removal of the elongate adhesive article 20 from a substrate on which it is disposed, user would lift an edge of the removable strip 28 from the substrate starting between the pair of slits 27 using for example, a finger nail. In this manner, the pair of slits 27 acts as a “pick point”, or “starting point”. User would then tear lines of weakness 26 starting from first side edge 21a, along their length across the backing layer, and remove the removable strip 28. The user can then use the torn edges remaining on the elongate adhesive article 20 as a tab to aid in the removal of the remaining pieces of article 20 from the substrate.
Details of backing layer 21, adhesive layer 22, and lines of weakness 26, and slits 27 are the same as those discussed in the first embodiment (
As shown in
As shown in
Slits 27 may be any shape, including circular, elliptical, linear, arrow- or V-shaped, Y-shaped, S-shaped, chevron, or partial-chevron. In some embodiments, a simple linear pattern of slits is used, in which the slits are aligned to create a single, broken separation line that extends laterally across the elongate adhesive article 10.
Slits 27 may be perpendicular to the side edge 11a of the backing material or they may be arranged at an angle other than 90°. However, the lines of weakness 26 associated with such angled slits are preferably substantially perpendicular.
In some embodiments, slits 27 are of equal length. The length of the slits may range from about 0.1 mm to about 5 mm, preferably from about 0.25 mm to about 3 mm. If it is desired to minimize the length of the slit and to reduce the likelihood of premature removal of the removal strip, one may desire to limit the slit to a length of between about 0.5 mm and about 1 mm.
Also, as shown in
As mentioned above, to aid in the removal of the elongate adhesive article 20 from a substrate to which it is adhered, user lifts backing layer 21 starting between the pair of slits 27. User then tears perforations 26, starting from first side edge 21a, along their length (along the y-axis), and removes the removable strip 28. In embodiments where the peel strength of the third adhesive section 22c is less than the peel strength of adhesive sections 22a and 22b; thus removal of the removable strip 28 is made easier.
To aid in the removal of bandage 40, user would lift the removable strip 49 starting between the pair of slits 47 using for example, a finger nail. In this manner, the pair of slits 47 acts as a “pick point”, or “starting point”. User would then tear along the lines of weakness 46 starting from one side edge of backing layer 41, across the width of the backing layer, and remove the removable strip 49. The user can start from either first side edge 41a or second side edge 41b of backing layer 41, as each side has a “pick point”. The user can then use the torn edges remaining on bandage 40 as a tab to aid in the removal of the remaining pieces of bandage 40.
Details of backing layer 41, adhesive layer 42, lines of weakness 46, and slits 47 are the same as those discussed in the first and second embodiment (
Bandages 40 as shown in the third embodiment have an absorbent pad 45 associated with first surface of the backing layer 41. Absorbent pad 45 includes a first surface facing the second surface of backing layer 41, and that has a first surface area, and a second surface opposite the first surface and facing the skin, and that has a second surface area. As used herein, “associated with the backing layer” means that absorbent pad 45 is affixed either directly or indirectly to backing layer 41 so that it will not become separated from absorbent pad 45 during normal use.
Again, a user can remove the bandage 40 by lifting an edge of the removable strip 49.
a to 10c are a representation of one removal method of the second embodiment the elongate adhesive article 20 of the present invention from a user's index finger 62.
The process of manufacturing the elongate adhesive articles described above may be any of those conventionally known to produce adhesive bandages. The backing layer and adhesive layer can be obtained by any methods available at present. For example, an extrusion process may be used for obtaining the backing layer. In the same way, the adhesive layer can be made in any known manner. A backing layer as described herein is obtained and an adhesive layer as described herein is applied to the second surface of the backing layer. Optionally, a release layer may be applied to the adhesive layer. The release layer is removed from the adhesive article prior to application by the user.
The process of manufacturing the adhesive bandages articles described above may be similar to the method described above for adhesive articles. The added component, the absorbent pad, can be obtained by any methods available at present. After adhesive layer is applied to the second surface of the backing layer as described herein, the absorbent pad is associated with the adhesive layer, thus bonding the absorbent pad to the backing layer.
The lines of weakness described above may be formed by a variety of manufacturing processes. In some embodiments, mechanical punches may be employed to perforate the materials. Hot pin perforation, also known in the prior art, may be used in the manufacturing process. Kiss cutting and die cutting are also known processes that may be employed to perforate, slit, and/or score.
Ultrasonic perforation is also employed in the prior art. Ultrasonic systems employ ultrasonic equipment adjacent to a pin roll with a fixed gap of space in the path of the web between the ultrasonic equipment and the pin roll. In one embodiment, the ultrasonic system includes a nip roll for providing tension to the web, a pin roll constructed of hardened and/or unhardened steel and a wear resistant coating, and an ultrasonic horn, which is cooled by a stream of forced air. The ultrasonic horn and pin roll are preferably positioned so that there is no gap between the two, and no calibration or extremely precise machining of the pin roll is required. The method of the invention includes holding the web in tension, perforating the web with ultrasonic equipment which is immediately adjacent to a pin roll, and cooling the ultrasonic equipment with a forced stream of air. The resulting material has well defined holes without abnormal tearing, and has a smooth surface with no raised annular edges around the holes.
As mentioned above, in some embodiments the peel strength the weakened region may be less than the peel strength in other regions of the first, adhesive surface. This can be accomplished several ways. An adhesive having a lower peel strength can be applied in the region corresponding to the removable strip by methods such as using a slot coating die. Alternatively, the adhesive layer may be configured in discontinuous patterns on the backing layer, with less, or no adhesive applied in the region corresponding to the removable strip. This can be accomplished using a screen, a spray or any other method which a person skilled in the art understands as to use to form a discontinuous layer of adhesive. In other embodiments, the region of adhesive corresponding to the removable strip can be covered with permanent facings, such as, a thin backing or sheet material of lesser adhesiveness. One such material is plastic netting sold under the trade name DELNET (Delstar Technologies, Middletown, Del.).
The elongate adhesive articles described above may also be ideally suited to deliver one or more active ingredients such as therapeutics to the surface of the skin. When contained in the bandages 40 of the invention, one or more active ingredients may be contained primarily or exclusively in the absorbent pad 45 of bandage 40. Illustrative classes of active ingredients that may be delivered to the skin via the elongate adhesive bandages 40 of the invention include, but are not limited to, antibiotics, analgesics, antipyretics, antimicrobials, antiseptics, antiallergics, anti-acne, anesthetics, anti-inflammatories, hemostats, cosmetics, vitamins, vasodilators, emollients, pH regulators, antipruritics, counterirritants, antihistamines and steroids. Specific active ingredients that may be delivered to the skin via the dressings of the invention include chlorhexidine, neomycin sulfate, polymyxin-B sulfate, zinc bacitracin, benzalkonium chloride, cetylpyridinium chloride, bupivacaine, tetracaine, cincaine, lidocaine, benzocaine, silver sulfadiazine, hydrocortisone, metandienone, trypsin, tolazoline, heparin, pramoxine, aloe vera, tretinoin, retinol, retinaldehyde, menthol, capsaicin, alpha hydroxy acids and vitamins such as Vitamin E.
The present invention will be better understood from a consideration of the following illustrative examples.
Prototypes were handmade using commercially available wound covering bandages. The commercial bandages used are sold under the trademark BAND-AID® Brand Adhesive Bandages by Johnson & Johnson Consumer Products Company (Skillman, N.J.). The bandages used are sold under the names “Sheer Strips” and “Flexible Fabric”. The dimensions of both bandages were 3-inch length by 0.75-inch width.
The process for making prototypes started with removing the outer wrapping of the bandage. Next, the release layer was removed from the adhesive areas. The bandage was placed, adhesive side down, on a smooth polypropylene sheet that was coated with a thin layer of hand cream. The hand cream kept the adhesive side from strongly adhering to the polypropylene sheet. The polypropylene sheet was placed on a stack of about ten 5-cm by 5-cm POST-IT® Note sheets (3M, Minneapolis, Minn.). The sheets served as cushioning for the cutting procedure.
Slits and pick points were created in the bandage backing layer using a model X3602#2 X-ACTO knife (Elmer's Products, Inc., Westerville, Ohio) to cut four slits (two parallel pairs) through the backing layer. The disposition of the slits was similar to the location of slits 47 shown on
The process for making prototypes was completed by removing the bandage from the smooth polypropylene sheet, and replacing the release layer on the adhesive area.
To demonstrate use of the prototype bandage, the release layer was removed from the bandage, and the bandage was wrapped, adhesive side down, around the index finger of a user. The bandage was wrapped so that there was an overlap of the backing layer. To remove the bandage, the user used a finger nail from the opposite hand to lift a portion of the releasable strip. The user then tore the perforations along their length, removing the removable strip. The user then used the torn edges of the prototype bandage as a tab to unwrap the rest of the bandage from the index finger.
While various embodiments of the invention have been set forth above, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.
