U.S. patent application number 12/217173 was filed with the patent office on 2008-10-30 for easy-to-peel securely attaching bandage.
This patent application is currently assigned to I DID IT, INC.. Invention is credited to Ernest D. Buff, Marni Markell Hurwitz, Dave Narasimhan.
Application Number | 20080269661 12/217173 |
Document ID | / |
Family ID | 38620395 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080269661 |
Kind Code |
A1 |
Hurwitz; Marni Markell ; et
al. |
October 30, 2008 |
Easy-to-peel securely attaching bandage
Abstract
A bandage remains securely attached to the skin of a wearer
during extended exposure to arid, humid or wet conditions. The
bandage is readily removed from the attached condition upon
application of pressure to its exterior surface. Adhesive portions
of the contain pockets or microcapsules filled with an
adhesive-inactivating ingredient. The pockets are formed in the
backing layer. Microcapsules, if present, are incorporated in the
adhesive. The adhesive inactivating ingredient comprises oil from
vegetable source, mineral source or fatty acids. The wearer
ruptures the pockets or microcapsules by applying pressure to the
bandage above the adhesive portions. The adhesive-inactivating
ingredient is thereby released at the skin-adhesive interface,
permitting an easy, pain-free removal of the bandage.
Inventors: |
Hurwitz; Marni Markell; (Far
Hills, NJ) ; Narasimhan; Dave; (Flemington, NJ)
; Buff; Ernest D.; (Far Hills, NJ) |
Correspondence
Address: |
Ernest D. Buff;Ernest D. Buff & Associates, LLC
231 Somerville Road
Bedminster
NJ
07921
US
|
Assignee: |
I DID IT, INC.
|
Family ID: |
38620395 |
Appl. No.: |
12/217173 |
Filed: |
July 2, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11408502 |
Apr 21, 2006 |
7396976 |
|
|
12217173 |
|
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Current U.S.
Class: |
602/57 ; 156/196;
427/207.1 |
Current CPC
Class: |
A61F 13/0203 20130101;
A61L 15/58 20130101; Y10T 156/1002 20150115 |
Class at
Publication: |
602/57 ;
427/207.1; 156/196 |
International
Class: |
A61L 15/50 20060101
A61L015/50; B29C 65/52 20060101 B29C065/52; B05D 5/10 20060101
B05D005/10 |
Claims
1. A bandage, comprising: a. a backing layer; b. a plurality of
portions of the backing layer containing an adhesive appointed for
contact with skin of a bandage wearer; c. a plurality of
microcapsules containing an adhesive-inactivating ingredient
disposed in the adhesive-containing portions of the backing layer;
d. said microcapsules being operative to rupture upon application
of pressure or scratching by the bandage wearer, thereby releasing
said adhesive-inactivating ingredient; e. said
adhesive-inactivating ingredient, upon release, being delivered at
the skin contacting interface of said adhesive, reducing adhesive
bond strength and enabling pain-free removal of said bandage. f. a
central wound-contacting absorbent pad bonded by hot melt glue or
strong adhesive to said backing layer; wherein said backing layer
is embossed with microcapsules, filled with said
adhesive-activating ingredient and sealed with a second polymeric
layer prior to the application of said adhesive.
2. A bandage as recited by claim 1, wherein the adhesive is
selected from a group consisting of acrylic-based, dextrin-based,
and urethane-based adhesives, and adhesives based on natural and
synthetic elastomers.
3. A bandage as recited by claim 1, wherein the adhesive releasing
ingredient is a member selected from the group consisting of
vegetable oil, olive oil, safflower oil, cotton seed oil, peanut
oil, soybean oil, caster oil, sesame oil, mineral oil, liquid
paraffin or fatty acids, and mixtures thereof.
4. (canceled)
5. (canceled)
6. A bandage as recited by claim 1, wherein said microcapsules are
present in the adhesive contained by the adhesive-containing
portions of said backing layer.
7. (canceled)
8. (canceled)
9. A bandage as recited by claim 1, wherein said microcapsules
contain about 5 to 20 volume percent of adhesive-inactivating
ingredient as compared to the volume of said adhesive.
10. A method for producing an easy-to-peel, securely attaching
bandage, comprising the steps of: a. selecting a first polymeric
layer; b. embossing said first polymeric layer to form a plurality
of microcapsules therein; c. filling said microcapsules with an
adhesive-inactivating ingredient; d. selecting a second polymeric
layer; e. spreading said second polymeric layer over said first
polymeric layer to cover said filled microcapsules; f. bonding said
second polymeric layer to said first polymeric layer to form filled
microcapsules of adhesive-inactivating ingredient having a backing
layer; and g. applying skin-contacting adhesive to portions of said
backing layer, whereby release of the adhesive-inactivating
ingredient can be triggered, and said bandage can be removed from
the skin easily and without pain, when the wearer applies pressure
to or scratches the backing layer, causing rupture of said
microcapsules.
11. A method for producing an easy-to-peel, securely attaching
bandage, comprising the steps of: a. producing microcapsules that
contain an adhesive-inactivating ingredient; b. mixing said
microcapsules with a skin-contacting adhesive to produce a
microcapsule-containing adhesive; c. selecting a backing layer; d.
coating said skin contacting portions of the bandage with said
microcapsule-containing adhesive; whereby release of the
adhesive-inactivating ingredient can be triggered on demand,
enabling said bandage to be removed from the skin easily and
without pain, upon application of pressure to the backing layer,
and consequent rupture of said microcapsules.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to bandages; and, more
particularly to releasable bandages, such as wound dressings, gauze
retainers or splints that remain securely attached during use, but
can be painlessly released upon demand.
[0003] 2. Description of the Prior Art
[0004] Bandages are well known in the art and are used for various
medical applications and sports protection. Sterile bandages
marketed under well-recognized trade names, such as `Band-Aid`,
`Cural` and the like, that provide secure attachment of the
bandage's adhesive portion to bare skin adjacent to a wound. A
sterile wound-covering pad contacts the wound. More recently,
adhesives have been developed for bandages that do not peel off
even when the bandage is wetted by sweat or swimming activity. The
corners of the bandages are oftentimes shaped to prevent easy
release of the bandage. All these developments prevent easy removal
of the bandage, especially when the area of the skin is covered
with hair. Bandage removal is typically so painful that most
patients and doctors remove the bandage by pulling sharply, as fast
as possible, to minimize the duration of pain. No solution is
presently available that allows easy, pain-free or reduced-pain
removal of a bandage. The pain problem becomes more severe as the
size of the bandage increases, as is the case for splint
restrainers or gauzes.
[0005] Several patents detail construction of bandages and
selection of adhesives, which improve skin adhesion. Some patents
address the shape of the bandage so that the edges do not readily
peel off. Some patents provide a covering that prevents the
wound-contacting portion of the dressing from sticking to the
wound, thereby reducing pain of bandage removal. None of these
patents addresses the problem of pain associated with removal of
the adhesive tape that retains the bandage against the skin.
[0006] Several patents address use of release layers normally
coated on the side of a bandage opposed to the adhesive coated
surface, enabling the peeling of a wound adhesive tape. This
release layer is applied to the backside that is opposed to the
adhesive side of the polymeric tape and has nothing to do with the
release of the tape from the skin. These tape release compositions
are not discussed. In fact, the presence of this release layer on
the skin is not useful since the tape will no longer adhere to the
skin.
[0007] U.S. Pat. No. 4,140,115 to Schonfeld discloses pressure
sensitive adhesive compositions for coating articles to be attached
to skin. Skin damage, i.e., the stripping of tissue cells from the
stratum corneum, caused by removal of a backing material which has
been held in adherent contact with a skin surface by means of a
pressure sensitive adhesive composition coated on the backing
material, is markedly reduced by incorporation of about 4 to 20% by
weight of an unreacted polyol uniformly dispersed in the
water-insoluble pressure sensitive adhesive mass. Suitable polyols
include polyethylene glycol and polypropylene sorbitol monolaurate.
The unreacted polyol is always present in the adhesive reducing the
tackiness of the adhesive and easy release of the adhesive tape is
achieved at the expense of the adhesive properties.
[0008] U.S. Pat. Nos. 4,693,776 and 4,732,808 to Krampe et al.
disclose macromer reinforced pressure sensitive skin adhesive sheet
material. A skin adhesive coated sheet material is provided which
is coated with a polymer that exhibits an enhanced level of initial
adhesion when applied to skin but resists objectionable adhesion
build up over time. The skin adhesives are comprised of a macromer
reinforced acrylate copolymer, which has a creep compliance value
at least about 1.2.times.10.sup.-5 cm.sup.2/dyne. A stable chemical
complex of iodine, iodide and a pressure-sensitive adhesive is also
provided wherein the adhesive has a creep compliance value of at
least about 1.0.times.10.sup.-5 cm.sup.2/dyne measured when the
adhesive composition is substantially free of iodine. The adhesive
contains a monomeric acrylate or methacrylate ester of a
non-tertiary alcohol, at least one ethylenically unsaturated
compound copolymerizable with monomeric acrylate or methacrylate
ester and a macromer. The addition of these macromer is always
present in the adhesive, which degrades as a function. Easy peel of
the adhesive layer does not occur until this degradation has
occurred and the bandage cannot be removed without pain at any time
selected by the user.
[0009] U.S. Pat. No. 5,412,035 to Schmitt et al. discloses
pressure-sensitive adhesives. Pressure-sensitive adhesive
compositions containing a crystalline polymeric additive having a
molecular weight of less than 25,000 and a melting point greater
than 23 degree C., preferably 30 to 60 degree C., coated on a
flexible backing. The presence of the additive causes the pressure
sensitive adhesive to lose adhesive strength when heated to the
melting point of the additive. The base resin of the pressure
sensitive adhesive is a polyacrylate or a styrene/butadiene
copolymer. The additive, which is a side chain crystallizable
polymer, is present in an amount ranging from 1 to 35%. Heat has to
be applied to release this bandage. Application of heat to a wound
is extremely painful and may, in the worst case, retard the healing
process of the wound.
[0010] U.S. Pat. No. 5,947,917 to Carte et al. discloses an
adhesive bandage or tape. A water resistant, flexible, dermal
adhesive product for conformable topical application to human skin,
the dermal adhesive product comprising a backing sheet having an
adhesive for removably adhering the sheet to the skin, wherein the
adhesive is a highly crosslinked pressure sensitive adhesive
composition comprising the polymerization reaction product of about
75% to about 95% of a mixture of at least two alkyl acrylate or
methacrylate esters, about 1% to about 10% ethylenically
unsaturated carboxylic acid, and about 10% to about 20% vinyl
lactam, by dry weight of solids, preferably about 80% to about 90%
of a mixture of at least two alkyl acrylate or methacrylate esters,
about 2% to about 5% ethylenically unsaturated carboxylic acid, and
about 10% to about 20% vinyl lactam, by dry weight of solids. This
water resistant adhesive for bandage is very effective in attaching
to the skin of the user; but is difficult to peel without undue
pain.
[0011] U.S. Pat. No. 6,077,589 to De Carvalho discloses adhesive
tape. The adhesive tape substratum is embossed to provide an
increased apparent thickness with protuberances and projections.
The adhesive contacts the skin only at the apexes or extreme points
of projections, leaving the remainder of the skin substratum
distant. This arrangement allows free circulation of air and water
vapor near to or around the non-adhered regions. The adhesive is
said to be easier to peel, due to its limited contact area with the
skin; but does not allow secure retention of the bandage.
[0012] U.S. Pat. No. 6,368,687 to Joseph et al. discloses a low
trauma adhesive article. A low trauma pressure-sensitive adhesive
coated substrate comprising a sheet material, tape or laminate
structure designed to adhere to skin or like surfaces. The
pressure-sensitive adhesive layer of this adhesive coated substrate
is a fibrous adhesive layer generally having a basis weight of from
5 to 200 g/m.sup.2 applied to a conformable backing or substrate.
The fibrous adhesive layer has a textured outer face and persistent
porosity between discrete adhesive fibers. Generally, the fibrous
adhesive layer has a MVTR (measured by ASTM E 96-80 at 40.degree.
C.) of at least 1000 g/m.sup.2/day, preferably at least 6000
g/m.sup.2/day. The adhesive fibers comprise polyalphaolefin
adhesive or acrylate pressure-sensitive adhesive. These fibers have
to be bonded to the backing by means other than relying on the
pressure sensitive adhesive coating applied to the fibers. The easy
peel of these fibers is only due to the limited contact between the
fibers and the skin surface. This limited skin contact feature also
limits the adhesive property of the backing strip to the skin,
preventing secure attachment of the bandage.
[0013] U.S. Pat. No. 6,566,577 to Addison et al. discloses wound
dressings having low adherency. The wound dressings are of the
island type, having as adhesive-coated backing sheet and an
absorbent island supported on the backing sheet. The island
comprises a layer of liquid absorbent material enclosed in an
envelope of textured perforated ethyl methyl acrylate thermoplastic
film. The film presents a ribbed or embossed perforated surface
having low adherency to the wound. The film island at the rear
surface of the envelope is perforated and smoothed to provide good
attachment to the backing sheet with controlled water vapor
transmission rate. The liquid absorbing island of the wound
dressing has low adherency to the wound due to the presence of rib
textured perforated thermoplastic film. The backing sheet that
carries the absorbing island is adhered to skin to retain the wound
dressing and no disclosure is provided for easily peeling this
backing sheet from the skin with undue pain.
[0014] U.S. Pat. No. 6,743,964 to Yoshida et al. discloses a pad
and adhesive bandage. A pad has an approximate-quadrangular portion
and approximate-arched portions attached to both lateral sides of
the approximate-quadrangular portion. All the periphery of the pad
is sealed with ultrasonic treatment. L represents the length of the
approximate-quadrangular portion in the direction parallel to the
lateral axis, S represents the length of the
approximate-quadrangular portion in the direction parallel to the
vertical axis and R represents a radius of said approximate-arched
portion. The geometrical relation between L, S and R satisfies
following relations.
0.5S< or =L< or =4S between L and S;
0.5S< or =R<S between S and R.
[0015] The pad prevents peeling-off from four corners thereof and
intrusion of water. This is a geometrical relationship between the
dimensions of the elements of the adhesive pad when exposed to
moisture. This disclosure does not suggest a method or means for
enabling a bandage to be peeled easily without pain.
[0016] U.S. Pat. No. 6,747,183 to Siegwart et al. discloses an
adhesive bandage with improved comfort and fit. An adhesive bandage
having a backing material; an adhesive applied to at least one
second major surface of the backing material; and a wound
contacting a pad secured to the backing by a portion of the
adhesive. The bandage has a tapered portion and a non-tapered
portion with rounded edges. The length of the tapered portion of
the bandage ranges from about 30% to about 70% of the total length
of the bandage. The adhesive to bond the wound-contacting pad
includes a hot melt adhesive or styrenic block copolymers and
tackifying resins, or ethylene copolymers, including ethylene vinyl
acetate copolymers. The adhesive for the bandage portion includes
acrylic based, dextrin based, and urethane based adhesives as well
as those based on natural rubber or synthetic elastomers including
amorphous polyolefins, for example, amorphous polypropylene. The
comfort of the adhesive bandage is due to the geometrical shape of
the adhesive ends and does not allow easy painless removal of the
bandage.
[0017] U.S. Pat. No. 6,942,683 to Dunshee discloses a wound closure
system and method. The system uses a flowable adhesive together
with wound closure such as wound bridge. The skin paint includes
1-40% of a siloxane-containing polymer; 60-99% of an Alkane-Based
Siloxane Polymer Reaction Solvent; and 0-15% of adjuvants.
[0018] U.S. Pat. No. 6,946,177 to Abe et al. discloses an adhesive
composition and adhered structure, which can be thermally peeled
with ease. The adhesive composition contains (i) from 55 to 95 wt.
% of a tackifying polymer and (ii) from 4 to 40 wt. % of a
crystalline polycaprolactone polymer based on a total weight of the
composition. The tackifying polymer is cross-linked polymer that is
compatible with the polycaprolactone which melts upon application
of heat allowing easy peel of the adhesive. Application of heat
also heats the wound in addition to heating the adhesive ends of a
bandage, which is extremely painful and damaging to the wound.
After peeling, the melted polycaprolactone is retained on the skin,
which may cause irritation of skin.
[0019] Notwithstanding the efforts of prior art workers to
construct a bandage that adheres to the skin securely in wet and
dry conditions, these progressive developments have inherently
resulted in bandages that are more difficult to peel of the skin
especially when the user of the bandage has hair on the skin,
resulting in extreme pain. Compositions and structures that
decrease adhesion due to the incorporation of monomeric precursors
of polymers or the geometrical approaches that limit the area of
contact of the adhesive with the skin also compromise the overall
adhesion of the bandage, resulting in inferior products. There
remains a need in the art for a flexible bandage that adheres well
to the skin and is easily removable from the skin at will without
causing excessive pain to the user. This need has been exacerbated
by the inherent difficulty in creating an bandage adhesive that
bonds well and, at the same time, can be readily removed with
minimal pain during peeling of the bandage away from the skin.
SUMMARY OF THE INVENTION
[0020] The present invention provides a flexible bandage that
adheres well to the skin and is readily removed upon demand.
Bonding of the bandage to the skin is so strong that the bandage
can remain securely in place--even under water--for an extended
period of time. Removal of the bandage is painless. The user
experiences substantially no pain during peeling of the bandage
away from the skin.
[0021] Generally stated, the bandage has an adhesive layer
comprising at least one pocket (and preferably a plurality of
pockets) or a plurality of microcapsules of an adhesive
inactivating ingredient that is readily released when the user
desires to remove the bandage. The bandage for example, may be
removed by the application of pressure to the external surface of
the adhesive portion or by scratching the external surface of the
bandage. This application of pressure causes the pockets or
microcapsules to break, releasing the adhesive inactivating
ingredient. Due to the arrangement of the microcapsules within the
adhesive layer, the adhesive inactivating ingredient is released at
the interface between the skin and the adhesive-coated backing
layer, enabling the bandage to be peeled away from the skin easily
and without pain.
[0022] The backing layer of the bandage may be provided with
pockets that contain the adhesive inactivating ingredient.
Alternatively, the adhesive inactivating ingredient may be
contained in capsules or microcapsules that are applied
concurrently with the adhesive layer of the bandage. The overall
volume of the pockets or microcapsules determines the amount of the
adhesive inactivating ingredient available. Once released, the
adhesive inactivating agents spread to an area at the skin-adhesive
interface that defines the region of adhesive inactivation. The
pockets included in the backing layer may be spaced apart, and the
size of the pockets may be large enough to inactivate the adhesive
in the region therebetween. However, when microcapsules are used,
they may be distributed more uniformly and closely spaced, since
each of the microcapsules contains only a small amount of the
adhesive inactivating ingredient.
[0023] The adhesive inactivating ingredient is contained in pockets
within the backing sheet in the first embodiment of the invention.
In the second embodiment of the invention, the adhesive
inactivating ingredient is contained in microcapsules that are
incorporated in the adhesive layer. In the first embodiment, the
backing sheet is fabricated from two polymeric sheets. The first
polymeric sheet is embossed to create the packets and filled with
the adhesive inactivating ingredient. The shape of the pockets may
be spherical, cylindrical or elongated or any suitable shape. The
pockets may be interconnected to form a continuous single pocket
such as an interconnected channel. The pockets may be arranged to
have a decorative shape such as a picture frame that is within a
short, approximately 1/8 inch to 5/16 of an inch, distance from the
edges of the bandage skin contacting portion. The central portion
of the picture frame may have one or more x-shaped interconnected
pockets providing a decorative appearance. The second polymeric
sheet, which is substantially thinner, is bonded to the first sheet
with embossed and ingredient filled pockets thereby encapsulating
the adhesive inactivating ingredient in the backing sheet. The
application of pressure or scratching the outer surface of the
backing sheet breaks the pockets on the thinner second polymeric
sheet thereby releasing the adhesive inactivating ingredient at the
skin-adhesive interface.
[0024] The glue used for attachment to skin comprises acrylic
based, dextrin based, and urethane based adhesives as well as those
based on natural and synthetic elastomers. The adhesives may also
include amorphous polyolefins including amorphous polypropylene,
such as HL-1308 from HB Fuller or Rextac RT 2373 from Huntsman
(Odesssa, Tex.). Water resistant adhesives include polymerization
reaction product two alkyl acrylate or methacrylate ester monomers
such as butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate,
isooctyl acrylate, isononyl acrylate, isodecyl acrylate, methyl
acrylate, methylbutyl acrylate, 4-methyl-2-pentyl acrylate,
sec-butyl acrylate, ethyl methacrylate, isodecyl methacrylate,
methyl methacrylate with ethylenically unsaturated carboxylic acid,
a vinyl lactam, and including a crosslinking agent.
[0025] It has been surprisingly found that an oily composition
inactivates the adhesive. The oily composition comprises oils
selected from vegetable oils such as olive oil, safflower oil,
cotton seed oil, peanut oil, soybean oil, caster oil, sesame oil
and the like and mineral based oils such as mineral oil or liquid
paraffin. Other oily compositions include fatty acids that have a
melting point lower than 20.degree. C.
[0026] The oily adhesive inactivating ingredient may be contained
in pockets of the embossed backing layer. The spreadability of the
oily adhesive inactivating ingredient is determined by its volume,
viscosity and its surface tension. Since pockets contain larger
volume of the adhesive inactivating ingredient, they can be spaced
apart further based on the volume. The volume is generally in the
range of 0.01 cc to 0.5 cc and the spacing between the pockets is
in the range of 0.01 cm to 0.2 cm. Microcapsules are generally
small and contain only a small quantity of adhesive inactivating
ingredient and can only spread over a small distance approximating
a few times the diameter of the microcapsule. However, these
microcapsules are added to the adhesive and are nearly uniformly
dispersed in the adhesive layer. Therefore, the appropriate measure
is the relative volume of the adhesive inactivating ingredient as
compared to the volume of the adhesive. This ratio is typically in
the ratio of 5 to 20%.
BRIEF DESCRIPTION OF THE DRAWING
[0027] The invention will be more fully understood and further
advantages will become apparent when reference is had to the
following detailed description of the preferred embodiments of the
invention and the accompanying drawings, in which:
[0028] FIG. 1a is a schematic diagram of a front view of a
conventional bandage with a wound contacting central pad and
adhesive coated end tabs that attach to the skin;
[0029] FIG. 1b is a schematic diagram of a cross sectional view of
a conventional bandage showing a wound contacting central pad, its
attachment to a backing layer and an adhesive coating provided on
the backing layer in the end tabs for attachment to the skin;
[0030] FIG. 2a is a schematic diagram of the first embodiment of
the invention depicting the front view of the bandage with pockets
of adhesive inactivating ingredient contained within the backing
layer of the adhesive coated end tabs of the bandage;
[0031] FIG. 2b is a schematic diagram of a cross sectional view of
a bandage according to the first embodiment of the invention
showing wound contacting central pad, its attachment to a backing
layer, a backing layer with pockets that contain an adhesive
inactivating ingredient and the adhesive coating provided on the
backing layer in the end tabs for attachment to the skin;
[0032] FIG. 3a is a schematic diagram of the second embodiment of
the invention depicting the front view of the bandage with an
adhesive inactivating ingredient contained in the form of
microcapsules that are present within the adhesive layer of the end
tabs of the bandage;
[0033] FIG. 3b is a schematic diagram of a cross sectional view of
a bandage according to the second embodiment of the invention
showing a wound contacting central pad, its attachment to a backing
layer, and end tabs with an adhesive coating on the backing layer
which contains a plurality of microcapsules that encapsulate
adhesive inactivating.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The present invention provides bandage that is well bonded
to the skin, and retains an absorbent pad, splint or the like,
providing a secure medical retaining device. Notwithstanding its
strong bond with the skin, the bandage can be readily peeled
therefrom with virtually no pain at any time at the convenience of
the wearer by either scratching or applying pressure to the outer
surface of the backing layer of the bandage at the adhesive
portion. This scratching action or application of pressure breaks
pockets or microcapsules that release an adhesive inactivating
ingredient at the skin-adhesive interface.
[0035] The bandage typically comprises a backing layer with a
central region for attachment to an absorbent pad and two end
portions which carry an adhesive coating that contacts the skin of
the user and attaches the bandage. The absorbent pad that contacts
the wound surface is attached to the central portion of the backing
layer by hot melt glue or conventional strong glue. Examples of
suitable adhesives include those based on styrenic block copolymers
and tackifying resins such as HL-1491 from HB-Fuller Co. (St. Paul
Minn.), H-2543 from ATO-Findley (Wawatausa, Wis.), and 34-5534 from
National Starch & Chemical (Bridgewater, N.J.). Ethylene
copolymers, including ethylene vinyl acetate copolymers, may also
be used as adhesives to bond the absorbent pad to the backing
sheet. This adhesive retains the absorbent pad on the backing strip
and has nothing to do with peeling of the bandage from the skin.
Bandages, which retain a splint or are used for sports purposes do
not generally, contain this absorbent pad attached to the central
portion of the backing layer.
[0036] The end portions of the backing layer are coated with an
adhesive coating that permits the attachment of the bandage to the
skin. There are specific requirements for the adhesive coating
composition. First, it must be able to contact the skin for a
prolonged period of time without irritating the skin. The adhesive
must have sufficient strength to retain the bandage against the
skin securely, thereby holding the absorbent pad in contact with
the wound, or retaining a splint. The adhesive cannot be rigid and
must be flexible enough to allow movement of the skin. Brittle
adhesives crack and fail easily. Technical improvements in this
area have focused on improving the quality of the adhesive and
strengthening its bond to the skin. The adhesive must also exhibit
a balance between its shear properties and adhesion properties,
which are inversely related. In a "wet flex" performance test for
adhesive bandages, when applied to fingers, the failure modes are:
(i) "flagging", that is, when the overlapped bandage pops open due
to a failure to adhere to itself; and (ii) "ring off", which occurs
when the overlapped bandage loses adhesion to the skin and slips
off. Typically, very soft, highly tacky adhesives exhibit low shear
strength, while hard adhesives are only slightly tacky and exhibit
high shear strength. An adequate degree of adhesive and shear
properties are required so that no adhesive residue remains when
the bandage is removed from the skin of the wearer.
[0037] The glue used for attachment of the bandage to the skin
comprises acrylic based, dextrin based, and urethane based
adhesives as well as those based on natural and synthetic
elastomers. The adhesives may also include amorphous polyolefins
including amorphous polypropylene, such as HL-1308 from HB Fuller
or Rextac RT 2373 from Huntsman (Odesssa, Tex.). Water resistant
adhesives include the polymerization reaction product of (i) two
alkyl acrylate or methacrylate ester monomers such as butyl
acrylate, ethyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate,
isononyl acrylate, isodecyl acrylate, methyl acrylate, methylbutyl
acrylate, 4-methyl-2-pentyl acrylate, sec-butyl acrylate, ethyl
methacrylate, isodecyl methacrylate, and methyl methacrylate with
(ii) ethylenically unsaturated carboxylic acid, (iii) a vinyl
lactam, and (iv) a crosslinking agent. Improvement in adhesive
strength properties have resulted in adhesives that bond well to
the skin and do not peel off or fall off even when the bandage
becomes wet. Unfortunately, the same factors that improve the
adhesive properties of a bandage, also make it very difficult to
remove the bandage from the skin. This is especially the case when
hair is present on the skin. Removal of a bandage that is highly
adhesive tends to pull or dislodge the hair follicles from the
skin, creating a very painful experience.
[0038] Prior art workers have contoured the shape of the adhesive
portion of the bandage to prevent edge peel. Efforts have been made
to incorporate monomeric acrylates or polyols to weaken the
adhesive, or to utilize additives that degrade the adhesive as a
function of time. These approaches deteriorate the adhesive,
reducing its performance. Prior art workers have also attempted to
emboss the backing layer, thereby limiting the contact regions of
the adhesive with the skin. This approach limits the adhesive
contact, thereby reducing the bonding strength of the bandage.
[0039] It has been surprisingly found that an oily composition
inactivates the adhesive. The oily composition comprises one or
more oils selected from a vegetable source such as olive oil,
safflower oil, cotton seed oil, peanut oil, soybean oil, caster
oil, sesame oil and the like and mineral based oils such as mineral
oil or liquid paraffin. Other oily compositions include fatty acids
that have a melting point lower than 20.degree. C.
[0040] The first embodiment of the invention uses pockets that
encapsulate the adhesive inactivating ingredient in the backing
layer of the bandage. This is conveniently accomplished by
preparing the backing layer as a two polymeric sheet construction,
wherein the first polymeric sheet is embossed to create pockets.
These embossing shapes may be spherical, cylindrical or elongated
and may be individually separated or interconnected. The pockets
are filled with an adhesive inactivating ingredient. A second
polymeric sheet, which is generally thinner and has low strength
properties, is spread over the first polymeric sheet, covering the
pockets. It is then heat sealed or sealed by other methods to
encapsulate the adhesive inactivating ingredient. This backing
layer is processed in the usual way by attaching the absorbent pad
using hot melt glue and applying the skin contacting adhesive to
the end portions of the bandage. When pressure is applied to the
outer surface of the backing layer, or the backing layer is
scratched, the pockets at the second polymeric sheet rupture,
releasing the adhesive inactivating ingredient at the skin-adhesive
interface. This release provides for easy, pain free removal of the
bandage, and can be triggered at any time that suits the
convenience of the wearer.
[0041] The second embodiment uses a standard backing layer commonly
used to fabricate bandages. The absorbent pad is attached at a
central location by hot melt glue. The adhesive that is applied to
the skin contacting end portions of the backing layer includes
microcapsules that contain the adhesive inactivating ingredient.
The adhesive bonds to the skin effectively and the bandage is
retained on the skin in the usual manner. When release the bandage
is desired, the wearer applies pressure to the adhesive portion of
the bandage, or scratches this region. The microcapsules rupture,
releasing the adhesive inactivating ingredient at the skin-adhesive
interface. With this release, there is effected a pain-free,
effortless removal of the bandage.
[0042] When a pocket or microcapsule breaks, it releases the
adhesive inactivating ingredient. How far the ingredient spreads is
a function of the volume of ingredient contained in the pocket or
microcapsule, and its viscosity and surface tension, or wetting
characteristics. High viscosity oils spread slowly. Reduced surface
tension promotes spreadability. Surfactants reduce the surface
tension and improve spreading capability. Viscosity may be
increased by the addition of thickeners. The pockets are generally
larger and therefore contain a larger volume of the adhesive
inactivating ingredient, and can spread the ingredient over a
larger distance. Typically the pockets may have a volume of 0.01 cc
to 0.5 cc and the spacing between the embossed pockets in the
backing layer may be 0.01 cm to 0.2 cm.
[0043] The microcapsules are generally small in diameter and
contain only a small volume of the adhesive inactivating
ingredient. The adhesive inactivating ingredient spreads
approximately a few times the diameter of the microcapsule.
However, there are many microcapsules, nearly uniformly distributed
in the adhesive layer. The appropriate measure of adhesive
inactivating ingredient is its overall volume as compared to the
volume of the adhesive used. The adhesive inactivating ingredient
volume is typically present in the range of about 5 to 20% of the
volume of the adhesive used. In this manner, the adhesive contains
the microcapsules, with the adhesive inactivating ingredient nearly
uniformly distributed, and affords sufficient volumetric release of
the adhesive inactivating ingredient for effective bandage
removal.
[0044] The oily composition should be contained in the pockets or
microcapsules indefinitely without chemical reaction or
dissolution. The second polymeric sheet encasing the pockets may
include a layer of polyethylene, which is immune to dissolution by
oily compositions. The adhesive inactivating ingredient may be
contained in microcapsules of polymeric or gelatin composition. Use
of gelatin, which dissolves in water, is not a problem when the
adhesive used is water resistant.
[0045] The method of manufacture of the microcapsules is well known
in the art and includes formation of polymeric bubbles that contain
the adhesive inactivating ingredient. For example, soybean oil can
be easily micro encapsulated in the reaction product of ethylene
diamine and toluene diisocyanate. Techniques for producing
microcapsules are detailed in `Microcapsules and other
capsules-Advances since 1975`, edited by M. H. Gutcho, 1979
published by Noyes Data Corporation, the disclosure of which is
specifically incorporated herein by reference.
[0046] FIG. 1a shows generally at 10 a schematic diagram of a front
view of a conventional bandage with a wound-contacting central pad
12 and adhesive coated end tabs 13 that attach the bandage to the
skin.
[0047] FIG. 1b shows generally at 11 a schematic diagram of the
cross section of a conventional bandage, taken along the line XX of
FIG. 1a. The wound contacting central pad 12 is bonded to the
backing layer 14 with hot melt or other permanent adhesive 15. The
backing layer is coated with a skin contacting adhesive 16 on end
tabs.
[0048] FIG. 2a shows generally at 20 a schematic diagram of the
first embodiment of the invention depicting the front view of a
bandage with a wound contacting central pad 12 and adhesive coated
end tabs 13 that attach the bandage to the skin. The end tabs 13
have a plurality of pockets 22 which contain an adhesive
inactivating ingredient 23. The pockets will be covered by the
adhesive on the skin contacting side. They will be buried within
the backing layer and will not be visible. Pockets 22 are shown in
the drawing for clarity.
[0049] FIG. 2b shows generally at 21 a schematic diagram of the
cross section of a bandage of the first embodiment of the present
invention, taken along the line YY of FIG. 2a. The wound contacting
central pad 12 is bonded to the backing layer 14 with hot melt or
other permanent adhesive 15. The backing layer 14 contains pockets
22, which contain adhesive inactivating ingredient 23. The backing
layer 14 is sealed with a second polymeric sheet 24. The adhesive
layer 16 coats the second polymeric sheet 24.
[0050] FIG. 3a shows at 30 a schematic diagram of the second
embodiment of the invention illustrating the front view of a
bandage with wound contacting central pad 12 and adhesive coated
end tabs 13 that attach the bandage to the skin. The adhesive
contains a plurality of microcapsules 32 that contain the adhesive
inactivating ingredient 33 within the adhesive layer 16 of the
bandage's adhesive coated end tabs 34. The microcapsules will be
generally invisible, since they are contained within the adhesive
coating of the end tabs. They are shown for clarity.
[0051] FIG. 3b shows at 31 a schematic diagram of the cross section
of a bandage according to the second embodiment of the invention,
taken along line ZZ of FIG. 3a. The wound-contacting central pad 12
is bonded to the backing layer 14 with hot melt or other permanent
adhesive 15. The backing layer 14 has a coating of adhesive 16 in
the skin contacting areas of the bandage, which contains
microcapsules 32 with adhesive inactivating ingredient 33.
[0052] The key features of the easy to peel securely attaching
bandage includes, in combination, the features set forth below:
[0053] 1. a bandage having a backing layer; [0054] 2. the backing
layer having a plurality of portions coated with adhesive for
attachment to skin; [0055] 3. optionally the backing layer having a
central portion permanently attached to an absorbent pad; [0056] 4.
the backing layer comprising individually separated or
interconnected pockets of an adhesive inactivating ingredient or
the adhesive-containing microcapsules of an adhesive inactivating
ingredient; [0057] 5. application of pressure to or scratching the
outer surface of the backing layer being operative to break the
pockets or microcapsules, thereby releasing the adhesive
inactivated ingredient at the skin-adhesive interface; and [0058]
6. the adhesive inactivating ingredient being an oil selected from
the group consisting of vegetable oils such as olive oil, safflower
oil, cotton seed oil, peanut oil, soybean oil, caster oil, sesame
oil, mineral based oils such as mineral oil or liquid paraffin or
fatty acids, and mixtures thereof.
[0059] The easy to peel securely attaching bandage disclosed herein
can be modified in numerous ways without departing from the scope
of the invention. For example, different bandages geometries,
diverse dispersions of adhesive inactivating ingredient
compartments, and a variety of release methods may be used. These
and other modifications are intended to fall within the scope of
the invention, as defined by the subjoined claims.
[0060] Having thus described the invention in rather full detail,
it will be understood that such detail need not be strictly adhered
to, but that additional changes and modifications may suggest
themselves to one skilled in the art, all falling within the scope
of the invention as defined by the subjoined claims.
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