Note: Descriptions are shown in the official language in which they were submitted.
93sg
1046373
COLD THERAPY ADHES IVE BANDAGE
The invention relates to improvements in
adhesive bandages and is particularly concerned with the
construction and assembly of adhesive bandages having
cold transmitting properties integrally associated
therewith.
A wide variety of products are currently
available on the market in the field of wound dressing~.
For example, sterile and medicated gauze-type dressings
are widely employed in hospitals after ma~or surgery
and also in the home for minor accidental in~uries.
However, in spite of their wide acceptance, the gauze-
type dressings are not without their disadvantages.
For instance, frequent changes of such dressings
are necessary in order to observe that the healing
process ic proceeding as desired. These frequent
changes are accompanied by discomfort to the
patient since some adherence to the wound or wound
exudate normally occurs. The gauze-type dressings also
require removal to renew medication.
Various polymeric materials have also been
investigated for use in the treatment of wounds, burns
and other skin disorders. For example, collagen, poly-
vinyl alcohol, gelatin and a wide variety of polymeric
2.
- . - - .. . .. , ~ .. - . ~ . ,
9359
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materials have been disclosed in the literature as
being useful in the treatment of accidental and
surgical wounds. However, in most instances these
materials are neither transparent, nor do they control
the growth of bacteria. Moreover, many patients have
been found to be allergic to these dressings which in
many instances necessitated a return to the use of the
gauze-type product.
Devices for lowering temperature at select
sites are also widely employed in the treatment of
animals and humans. Ice has been employed for many
years and is well known for relieving the discomfort
of pain and swelling and for injuries suffered
accidentally, in athletics or as a result of other
endeavors. However, while the well known ice pack
may have a degree of flexibility it requires the crush-
ing of ice, is cumbersome to use and does not provide
a uniform cooling surface. Moreover, as the ice or the
frozen water-alcohol mixtures attain room temperature,
it reverts entirely to the liquid state and provides
additional disadvantages in handling, particularly if
the enclosing container is not completely leakproof.
It has long been recognized that there is a
need for combining the advantages of a conventional
gauze-type wound dressing with a device for lowering
temperatures in one "overall" dressing or bandage.
Unfortunately however, prior art attempts have not been
entirely sati~factory due to the attendant disadvantages
' ' ' ~ .:
9359
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which far outweighed any benefits received. For
example, in the case where the absorbing material
is placed directly over the wound with the cooling
device over the absorbing material, there is a loss of
cooling efficiency to the wound due to the insulating pro-
perties of the absorbent material. Where ice or froze~ water-
alcohol mixtures are utilized as the cooling medium,
once the mixtures attain room temperature, they
revert entirely to the liquid state and are subject
to leakage in which case the absorbent dressing is
a 180 sub;ect to saturation.
~t i8 therefore an object of the present
invention to provide a novel, flexible adhesive bandage
having fluid absorbing as well as cold transmitting
properties integrally associated therewith. Another
ob~ect is to provide a novel dressing that can act as
both an absorbent for body fluid exudate from a wound
or in~ury as well as a colt therapy to the involved
area.
These and other ob~ects will become apparent
from the following description of the invention taken
in conjùnction with the accompanying drawings in which
Fig. 1 is a perspective plan view partially
cut away of the cold therapy adhesive bandage, exposing
the constituents.
Fig. 2 is a cross-sectional view taken along
the lines 2-2 of Fig. 1.
Fig. 3 is a bottom view with the release
4.
. .
.. . ..
.
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1046373 9359
strips pulled away exposing the dressing composite.
Fig. 4 is a view similar to Fig. 2 showing
a broader aspect of the invention, i.e., without the
outer covering and release strips.
Broadly contemplated, the present invention
provides a combination ab~orbent dressin& and flexible
cooling device comprising:
(a) a dressing composite comprising in com-
bination, a hydrophobic top sheet for
placement adjacent to the body and
having a plurality of valvular open-
ings therein, a substantially liquid
impermeable backing sheet, and an
absorbent material disposed between
said top sheet and backing sheet
and being characterized by its ability
to absorb liquid passed through
said openings, and a system of
dimples disposed on said top
sheet;
(b) a cooling device associated with
said dressing composite comprising
a flexible packaging material
encompassing and sealing an
insoluble hydrophilic gel; and
(c) an insulating material covering said
cooling device and said dressing composite.
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. . ... .. , , ~ ............. ~: . ~
. ~ . ~ '
~ 0~6 3 7 ~ 9359
Optionally, there is provided a release strip on the
lower surface of the device as protection against
contamination.
In a more specific aspect, the present
invention provides a combination absorbent dressing and
flexible cooling device comprising:
(a) an outer sheet having two end segments
containing an adhesive material on the
lower surfaces thereof and a middle
segment;
(b) a dressing composite comprising in com-
bination, a hydrophobic top sheet for
placement adjacent to the body and
having a plurality of valvular open-
ings therein, a substantially liquid
impermeable backing sheet, and an
absorbent material disposed between
said top sheet and backing sheet
and being characterized by its ability
to absorb liquid passed through said
openings, and a system of dimples
disposed on said top sheet;
(c) a cooling device disposed between said
outer sheet and said dressing composite
comprising a flexible packaging material
encompassing and sealing an insoluble
hydrophilic gel;
(d) an insulating material disposed between
said cooling device and said outer sheet; and
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(e) a release strip disposed on the lower
surface of said combination absorbent
dressing and flexible cooling device in
adhesive engagement with said end segments.
For a cle~rer understanding of the invention,
reference is made to the drawings and ~n partic~lar to
Fig. 1 thereof. The combination absorbent dressing and
flexible cooling device generally depicted by reference
numeral 10 (and hereinafter referred to as cold bandage,)
includes an outer sheet 11 which serves as the upper,
outer covering for the cold bandage. The outer sheet 11,
i8 preferably fabricated from a liquid impermeable
material, such as an olefinic or vinyl material. The
outer sheet 11, has two end segments 12 and 13 which
are adhesively treated on the bottom surface and a
middle segment 14 constituting the area between opposing
end segments 12 and 13.
Referring to Fig. 2, it will be seen that
situated below the middle segment 14 of the outer
sheet 11 is a dressing composite including an absorbent
material (pad) 15 substantially centrally located and
sandwiched between a thin, flexible backing sheet 16
of liquid impermeable material, such as polyethylene
or polyvinylidene chloride film, and a thin flexible
top sheet 17 also of a normally liquid impermeable
material. Top sheet 17 has a plurality of valvular
openings or slits 18 therein and a system of depressed
areas ~dimpleQ) 19 (both as shown in Fig. 3) which slits
and dimples will be described in greater detail hereinafter.
.. , , . : . :
9359
10 ~ 73
Backing sheet 16 and topsheet 17 are of approxi-
mately equal size and are of a length and width slightly
greater than the corresponding dimensions of absorbent
pad 15. The edges of backing sheet 16 and topsheet 17
are sealed to each other around the entire periphery
and iust outside the outermost edges of absorbent pad 15.
The sealing can be accomplished by any convenient means,
such as the use of an adhesive, but heat sealing is
preferred and is indicated by heat seal 22 around the
periphery of the topsheet and backing sheet. As shown
in Figs. 1 and 2, sitiuated between the outer sheet 11
and the dressing composite, is a cooling device containing
a flexible packaging material 24 which encompasses and
seals an insoluble hydrophilic ge~ 25. The cooling
device when in the frozen state, is of the type which is
easily moldable into various configurations without loss
of dimensional stability, and when in the unfrozen state,
the gel contained in said device does not flow.
The cooling device is insulated from the atmosphere
by provision of an insulating material 26 which is
disposed between the cooling device and the outer sheet.
It wiLl be noted that the overall dimensions of the
insulating material are greater than the backing sheet 16,
the topsheet 17 and the cooling device so that the
insulating material can effectively blanket the cooling
device and dressing composite. In order to prevent substantial
displacement of the insulating material and the cooling
device, the edges of the insulating material are adhered
such as by heat sealing and the like to the edges of the
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104ti373
topsheet 17 and the backing sheet 16. It will, of
course, be understood that this is a preferred embodiment
and that the insulating material need not be adhered as
shown.
In order to protect the lower surface of the
cold bandage from contamination, the cold bandage is
provided with release strips 27. The release strips 27
are adhered to the lower surface of the end segments 12
and 13 and prior to affixing the cold bandage to a
localized area, the release strips can be removed by
pulling on end tabs 28 and 29 in a manner such as to
remove the release strips from the cold bandage.
As mentioned previously, the outer sheet 11
is preferably fabricated from a liquid impermeable material
such as a polyvinylchloride, or polyethylene film.
The thickness of the film can vary within a range of
about ~05 to .2 mils. Various other type materials
can be employed such as non-woven cloth, treated
paper and the like, but are not as preferred as the
film materials. The adhesive utilized on the lower
surface of the end segments 12 and 13 can be of the
pressure-sensitive type conventionally employed in
the pressure-sensitive tape art. Thus, the pressure
sensitive adhesive has more self cohesion and adhesion
to ~he end segments than to either release strip or
to thç skin so that it peels easily from the latter
without depositing any adhesive. The material used
in the fabrication of the topsheet and backing sheet
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10~373
of the dressing composite of the present invention are
also not limited to any particular chemical composition
since it is their physical properties rather than their
chemical properties which are important in the articles
of the invention. These materials should, of course,
be thin, flexible, self-supporting, and substantially
water impermeable films. Preferably they are thermo-
pl~stic materials which are capable of being heat sealed
to each other.
The backing sheet 16 is preferably an olefinic
or vinyl film. Polyethylene or polyvinlidene chloride
film of a thickness of from about 0.4 to about 1.5 mils
are most preferred. ~ -
Any film which is useful as a backing sheet
will also be useful as a topsheet for the absorbent
dressing of the invention, It is preferable, however,
to use a film for the topsheet which resembles cloth
more closely in feel and appearance since it is this
portion of the article which will come in contact with
the skin of the user. One film which has been found
particularly useful is ethylene-ethyl acrylate film,
This copolymer is cloth-like, and soter than poly-
ethylene film. The film should have a thickness
of from about 0.4 to about 2.0 mils with about
1.0 to 1.5 mils being preferred.
A~ described above, the topsheet is made from
a substantially liquid impenmeable film and must be
provided with openings to be effective as the absorbent
dressing composite of the present invention. These
openings in the topsheet mu~t be capable of opening
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10~i373
to permit passage of liquid to the absorbent material.
The openings are preferably substantially straight slits
as contrasted to circular openings, curved openings
and the like, Thus, referring specifically to Fig. 3,
it will be seen that the topsheet, has a system of
openings (slits) identified by reference num~ral 18
and a system of depressed areas 19 (dimples). The
slits 18 are arranged in longitudinal rows in a manner
such that each row constitutes a longitudinal array
of substantially parallel straight slits each angularly
dispo8ed with respect to the longitudinal axis of the
row, Ad~acent rows are similarly disposed except that
the slits are arranged in a manner such that the end
points of each slit lie in a line substantially
between the end points of corresponding slits in the
ad~acent alternate rows. The slits useful in the
present invention are preferably substantially straight
slits. The slits should each be from about 0.03 to zbout
0.50 inch in length. Preferably there are from
about 10 to about 1000 slits per square inch, each
of such slits being from about 0.07 to about 0.20 inch
in length. The most preferredjfilm contains about 81
slits per square inch, each about 0.10 inch in length.
The slits can be formed according to the
methods and apparatus disclosed in U.S. Patent 3,762,255
issued October 2, 1973 and assigned to Union Carbide
Corporation.
The depressed areas (dimples) are distributed
across the surface of the topsheet in the manner shown in
Fig. 3. Thus, it will be seen that the topsheet 17 contains
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10~373
a plurality of dimples arranged in staggered parallel
rows along the surface of the topsheet 17 and which extend
above the plane of the topsheet (Figures 2 and 3).
The configuration of these dimples can be circu-
lar, eliptical, rectangular, diamond shaped, and the like, the
important criteria being that they be formed in a manner such
that topsheet is not broken during or after fabrication.
I have found that the full advantages of the
present invention are not achieved if, during fabrication
of the dimples, the topsheet is broken, cut or melted to
any signiflcant extent. I have found that the preferred
form of the dimple is circular as shown in Figures 2 and
3).
The dimples can be formed in the topsheet in a
variety of ways. The easiest and therefore the most
preferred method involves the use of a roller equipped
with heating means and having a number of spikes or probes
extending therefrom across the width of the roller and
around its circumference, The spikes, pins, or probes,
which have smooth, rounded end points, can be spaced as
desired on the roller in order to provide the desired
number of dimples to the dressing composite. The dimples
are provided on the dressing composite preferably after the
openings, but prior to complete fabrication of the dressing
composite, and this operation can be effected by passing
the dressing composite containing the openings in contact
with the heated roller. In this technique, the dre~sing
composi~e is supported on a resilient back-up member, such
as an endless conveyor belt, or a resilient back-up roller,
The depth of the dimple can be controlled by limiting the
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104~373
depth to which the probes depress the film. If desired,
portions of the topsheet may be retained in their untreated
(without the dimples) condition. This can be accomplished,
for example, along a narrow strip near the periphery of
the topsheet. Since the topsheet is thermoplastic, the
amount of heat and pres~ure applied to the areas to be
treated should be strictly controlled in order to avoid
sub~tantially puncturing the topsheet. As a general
rule, the amount of heat required should be enough to
~often the film, and the amount of pressure should be
sufficient to plastically distort the film to the general
contour of the probe. It will, of course, be understood
that the correct heat and pressure conditions will
depend (among othex variables) upon the residence time
of the treated dressing composite, i.e., the length of
time the topsheet is in contact with the roller; the
thlckness of the dressing composite pad, etc. The
correct conditions, however, can be easily ascertained
by one skilled in the art and hence no further
description of the conditions appears necessary.
Referring specifically to Figure 2, it will
be seen that the dimples 19 extend above the plane of the
topsheet 17 a short distance, and that the absorbent
material 15 immediately above the dimples, is in a
co~pressed stste. At the site where a dimple is formed
over a portion of a slit, that slit will be opened to a
much greater degree than corresponding slits situated
remote from the dimples 19, However, because of the
placement of the dimples, the slits disposed between
corresponding dimples are opened to a greater extent
1046373 9359
than would be the case if no dimples were present. This is
attributed to the fact that the pressure exerted on the
surface of the topsheet by the dimples causes the slits to
open slightly under the influence of the stretching of the
topsheet. Portions of the compressed absorbent pad are
associated with these opened slits, and because of this
association, almost instantaneous wicking is achieved.
As the liquid is transferred to the absorbent pad 15, the
absorbent pad absorbs the liquid throughout its entire area
until either partial or full saturation.
The dimples can be arranged on the absorbent
article in a variety of patterns. Thus, the overall
design effect can be diamond shaped, curvilinear, herringbone
and the like. The preferred design configuration is a
system of substantially straight staggered, parallel rows
along the surface of the topsheet. The number of dimples
per square inch of absorbent pad area can be varied over
a relatively wide range. Improvements have been noted
utilizing as little as 1 dimple (having a diameter of
.05 inch) per square inch of absorbent pad. I have further
observed that good results are obtained when as many as
100 dimples (.05 inch diameter) per square inch of
absorbent pad area are utilized. It wlll of course be
understood that the number of dimples per square inch of
absorbent pad area depends on the dimple size.
As a general rule, dimple size can be in the
range of about .025 to about 0.250 inch diameter. From
the standpoint of functional and aesthetic qualities, it
is preferred that the dimpl~ size range from about .075
to about 0.150 inch diameter.
The absorbent pad 15 can be one or more layers of
absorbent tissue paper or wadding stacked to the desired
thickness.
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104~;373
Absorbent materials other than tissue and
wadding will of course be useful in the diaper con-
struction of the present invention. For example,
absorbent non-woven pads can be fabricated to any
desired thickness and substituted for the absorbent
pads described above. One such absorbent pad which
has been used extensively in disposable diapers is
a wood pulp product commonly known as wood fluff and
is prepared in the same manner as a non-woven fabric.
In addition, foam materials having the desired degree of
absorbency can also be employed.
The only criteria for utility in the present
invention are that the material be absorbent, be capable
of being fabricated in the form of a pad, be compatible
with the liquid with which it will come in contact and
be non-irritating to the skin.
The flexible packaging material of the cooling
device can be a common plastic bag which is sealed around
the edges and is fabricated of a material which
has appropriate heat transfer rates. Merely as illustrative,
suitable materials for this purpose include films fabricated
from polyethylene or polyvinylidine chloride. Disposed
within the flexible plastic material is an insoluble
hydrophilic gel.
The term "insolubilization" as employed throughout
the specification and appended claims is utilized herein
to define the formation of a gel which is essentially solid
at temperstures below about 35-C. The insolubilization can
be effected by a wide variety of methods and includes,
15.
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1046373 9359
but is not limited to, ionizing and nonionizing radiation,
and chemical cross-linking through covalent and ionic
bonding.
In practice a wide variety of hydrophilic gels
can be employed in the preparation of the cooling device
of this invention. The only requirements of the particular
gel chosen is that it be capable of retaining relatively
large quantities of a liquid which can easily be transformed
from the liquid to solid state by simple cooling procedures.
If the liquid does not enter the solid state then it is
impossible to take advantage of the latent heat of fusion.
Although numerous liquids can be employed, water is preferred
in order to take advantage of the large heat of fusion
(144 B.t.u. per pound). Water can be employed as the sole
liquid, other liquids such as alcohols can be used, or
mixtures of water and other liquids or solutes can be
employed.
Illustrative hydrophilic gels which are useful
in the cooling device of this invention can be prepared by
appropriate techniques from the following starting materia~s,
among others;
Poly(ethylene oxide),
Polyvinyl wrrolidone,
Polyacrylamide,
Anionic polyacrylamide,
Polyvinylalcohol,
Maleic anhydride-vinylether copolymers,
Polyacrylic acid,
Ethylene-maleic anhydride copolymers,
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1046373
Po lyviny lether,
Dextran,
Gelatin,
Hydroxy propyl cellulose,
Methyl cellulose,
Carboxymethyl cellulose,
Hydroxyethyl-carboxymethyl cellulose,
Hydroxyethyl cellulose,
Propyleneglycol alginate,
Sodium alginate,
Polyethyleneimine,
Polyvinyl alkyl pyridinium halides, e.g. polyvinyl-n-butyl-
pyridinium bromide,
Polyproline,
Natural starches,
Casein,
Proteins,
Polymethacrylic acid,
Polyvinylsulfonic acid,
Polystyrene sulfonic acid,
Polyvinylamine,
Poly-4-vinylpyridine, polymerized monoesters of olefinic
acids, polymerized diesters of olefinic acids, acrylamide
and difunctional polymerizable materials, e.g. diacids,
diesters or diamides, and the like.
It should be noted that the starting materials
are not only those listed above, but includes copolymers
of one or more of either the aforementioned compounds
or materials similar to these. For example, copolymers
of ethylene oxide and minor or major amounts of other
17.
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104t;373
alkylene oxides can also be used.
In most instances, the gel need only contain
the insoluble swollen polymer and the liquid, e.g., water.
If desired however, it can also include other materials to
control the physical and chemical properties such as
freezing point, chemical stability, color, smell, crystal
size and growth rate.
Although a single reinforced layer exhibits
optimum conformability to the object being cooled, it is
sometimes neces~ary or de~irable to have a greater cooling
capacity than can be conveniently obtained in a single
layer. This can be achieved by the formation of a
multilayer device.
It has been observed that the optimum flexibility
and other desirable features are exhibited when the
layers of gel are separated from each other by a thin film
of an inert material. The frozen layers are then permitted
to slide easily over each other and contribute even
greater flexibility than that possessed by multilayers
of the gel alone.
In practice, gels can be made of any practical ,;~
thickneRs, width or length. In one embodiment gels have
been prepared as a continuous tape which measures 3 inches
wide by one-eighth of an inch thick. "Dacron" (a
registered trademark of DuPont Chemical Co., Inc.) gauzes,
both 9 and 20 holes per inch, which can be implanted in the
material as it i6 being insolubilized lend strength to
the resulting gel. Before being packaged the gels may ~-~
be swollen to their maximum liquid content. The product
i8 than cut into predetermined lengths, stacked, if a
multilayer device i8 desired, and then packaged in a
18.
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10~373 9359
polyethylene bag of the appropriate thickness. OptLmum
results are obtained when the gel layers have a separator
to separate them. This film can be applied during the
preparation of the gel. When cooling devices were made
with gel without the backing, the result was some loss
of flexibility when frozen.
Devices of 20 layers of gel and higher have
been made and found to have good flexibility.
The type of separator used to separate the gel
layers is not necessarily critical and a wide variety of
materials can be utilized. The only requirement of the
separator is that they be flexible at reduced temperature
and essentially unreactive with the gel. They do not
have to be a continuous film but can be perforated.
Moreover, the separator can be a material which is
applied to the surface of the gel and which effectively
prevents adhesion of the layers when stacked-such materials
include silicone surfactants, cetyl alcohol and the like.
Any of the numerous products currently on the market
can be employed with satisfactory results. For example,
separators can be composed of polyethylene, polypropylene,
polystyrene, polyvinylchloride, polyethylene terephthalate,
metal foils, and the like. Similarly, the outer covering
or enclosure in which the multilayers of gel are enclosed
can be fashioned from commercially available films or
other packaging materials.
The flexible cooling device of this invention can
be manufactured as a single use, disposable product or as a
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1046373 9359
reusable device. If the device is meant to be disposable
the outer enclosure can be a laminate with insulating
material, such as cloth, polymer foams, paper and the
like, on the outside. The inner portion of the laminate
can be a common plastic such as polyethylene, polypropylene,
and the like, to affect sealing or to protect the gel. A
metal foil can be part of the laminate to prevent the device
from drying out. The primary package can also have
attaching devices at each end to provide a means of securing
the cooling device to the area to be cooled. Finally, the
product can be manufactured and shipped as a sterile item
if desired.
A~ a re-usable cooling device, the outer enclosure
can be a common plastic bag sealed around the edges. This
unit can be supplied with an auxiliary bag into which the
tape i8 placed. This outer bag would be of a material
which hao appropriate heat transfer rates and may have
strings attached at both ends to be used to secure the
tape to the area to be cooled. Both types of product can
be packaged as a unitized structure for example, quilt
like in character. Appropriate performations can be
inserted so that the device can be divided into smaller
pieces.
In one preferred aspect, the novel cooling devices
of this invention are comprised of a hydrophilic, polymeric
gel of at least one insolubilized polymer of the formula:
~ IR3 IR4 ~ , . . ., -
Rl---t C--C--~ R2
Rs R6 n
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wherein Rl and R2 are selected from the group consisting
of hydrogen, alkyl radicals and alkyl substituted aryl
radicals, and wherein R3 is hydrogen when R4 is selected
from the group consisting of hydrogen, methyl, phenyl and
vinyl radicals, R4 is hydrogen when R3 is selected from
the group consisting of hydrogen, methyl, phenyl and vinyl
radicals, R5 is hydrogen when R6 is selected from the group
consisting of hydrogen, methyl, phenyl and vinyl radicals,
and R6 is hydrogen when R5 is selected from the group con-
sisting of hydrogen, methyl, phenyl and vinyl radicals, andn is greater than one.
These hydrophilic gels are polymeric compounds
containing at least one of the structural units shown below:
IRl lR2
- 1 ~ - ,
H
H
_ - I C--C _
R3 R4
Rl R2
_ -H 7 l~ - - _
_ -C--C--O- _
3 4
wherein Rl i8 hydrogen when R2 is selected from the group
consisting of hydrogen, methyl, phenyl and vinyl radicals;
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R2 is hydrogen when Rl is selected from the group consisting
of hydrogen, methyl, phenyl and vinyl radicals; R3 is hydrogen
when R4 is selected from the group consisting of hydrogen,
methyl, phenyl and vinyl radicals; and wherein R4 is hydrogen
when R3 is selected from the group consisting of hydrogen,
methyl, phenyl and vinyl radicals.
These hydrophilic polymerlc gel compounds may in-
clude carbon to carbon cross-linking between straight chain
carbon atoms and the carbon atoms of branch chain methyl
groups and between the carbon atoms of branch chain methyl
groups themselves. In addi~ion a very minor and insignificant
number of bonds may include two oxygen atoms linking the
carbon atoms.
The polymeric gel compounds may contain cross-
linking bonds present as inter-molecular bonds (e.g. between
two different molecules) and intramolecular bonds (e.g.
between carbon atoms of the same molecule), and combina-
tions of intra and intermolecular cross^linking bonds.
The proce8s for producing these polymeric gels
from poly(ethylene oxide) comprises preparing a homogene-
ous water solution of at least one of the water soluble
compounds selected from the following class of com-
pounds:
~ IR3 IR4
t f f ~
R5 R6 n
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wherein Rl and R2 are selected from the group consisting
of hydrogen, alkyl radicals and alkyl substituted aryl
radicals~ R3 is hydrogen when R4 is selected from the
group consisting of hydrogen, methyl, phenyl, and vinyl
radicals, R4 is hydrogen when R3 is selected from the
group consisting of hydrogen, methyl, phenyl and vinyl
radicals, R5 is hydrogen when R6 is selected from the
group consisting of hydrogen, methyl, phenyl and vinyl
radical~, R6 is hydrogen when R5 is selected from the
group consisting of hydrogen, methyl, phenyl and vinyl
radicals, and n is greater than one; submitting the solution
to ionizing radiation for a period of time sufficient to
cause insolubilization of the polymer.
The pH of the solution apparently is not critical
to the operability of the preparation of the polymeric gels
although the time required to cause formation of the gel-
like material can be considerably shortened by utilizing a
starting solution having a pH of about 7Ø
Temperature apparently is not critical to the
operability of the process since the gel-like material has
been formed in solutions having a temperature of just above
the freezing point of the starting solution.
In the treatment of polymers of ethylene oxide in
accordance with the presentinvention it is preferred to utilize
poly(ethylene oxide) having a molecular we~ght ranging
from about lX10 to about 10 ; a starting water solution
containing at least about 0.2 weight percent of poly(ethyl-
ene oxide); and submitting the starting solution to a total
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irradiation dosage of at least about 52.OX10 rads to
produce the gel-like material.
In general, after the hydrophilic polymeric
gels have been prepared, they can be used directly or
further modified by the addition of or the incorporation
of various agents, or other additives, as hereinafter
indicated. Moreover if a higher degree of flexibility of
the frozen hydrophilic polymeric gels is desired, it can be
accomplished by addition of small amounts of glycol such as
ethylene glycol and the like.
In addition to the use of an inert material as
a separator in the cooling device of this invention, the
device itself can contain various strengthening materials
throughout. For example, nylon gauze, rayon mesh, "Dacron"
(a registered trademark of DuPont Chemical Co., Inc.),
cellulose or other textile products mesh can be embedded
in the hydrophiLic gel, or fibers can be embedded in a
random orientation.
In practice, the hydrophilic gel forming step
2Q employed in the preparation of the polymeric gels can be
accomplished prior to, or simultaneously with the placement
of the inert separators and/or the incorporation of an
internal substrate or strengthening agent. An internal
substrate can be incorporated by dipping a matrix prior
to insoLubiLization into the aqueous poly(ethylene
oxide~ solution and then exposing it to insolubilizing
conditions. Other methods for placement of the substrate
wilL readiLy become apparent to those skilled in the art.
The novel cooling device of this invention
can be made with hydrophilic gels in a variety of thicknes~es
24. -
1 0~ ~'73 9359
ranging from one reinforced layer of 1 mill~meter
thickness or less, to 20 or more layers to give a total
thickness of several inches, or m~ e.
The insulating material 26 should be of the type
which i8 flexible, and has good insulating properties
so as to retard the effect of the difference in temperature
of the atmosphere and the cooling device Preferably, the
insulating material is a cellular material such as rubber
fo~m, polyurethane foam, polystyrene and the like Most
preferably, the material is capable of being heat sealed to
the backing sheet and top sheet of the absorbent composite.
The thickness of the insulating material would of course
depend upon the degree of protection required, the thickness
of the cooling device, the desired flexibility of the cold
bandage and other obvious considerations. For these
reasons, exact figures for the thickness of the insulating
material are not readily statable Suffice it to state
that the degree of thickness of the insulating ~aterial
can be easily assertained by one skilled in the art
depending on the above mentioned criteria.
The release (or protection) strips 27 can be
formed from materials commonly used inthe adhesive dressing
art.
The cold bandage of the present invention
can be fabricated by a wide variety of techniques.
Merely a~ illustrative, the absorbent composite and
cooling device can be independently fabricated and
placet over each other with the cooling device on
top of the ab~orbent composite, The insu~ting
25.
104f~373
material thereafter can be superimposed over the two and
adhered such as by heat sealing to the absorbent composite
as explained previously. Thereafter the middle segment
of the outer sheet can be superimposed over the entire
assembly and joined thereto. The release strip can
be added as a last step.
I have found that the cold bandage is
particularly suitable for the intended purpose. There
is very little tendency for the ice bandage to "stick"
to the wound as in conventional dressings. This is
partly attributable to the selection of materials
for the top sheet with ethylene ethylacrylate being
the preferred material. Moreover, absorption of body
exudate through the slits by the wicking action of
the absorbent material as enhanced by the dimples
is extremely rapid. Pinpoint transmission of "cold"
to the wound site is accomplished through the dimples
on the absorbent composite. I have found that the
cold transmission is extremely rapid when the dimple
contains some liquid on its surface. Thus, it will
be evident that the cold bandage of the instant
invention has fluid absorbing as well as cold trans-
mitting properties integrally associated therewith
without experiencing any of the disadvantages
characterlstically prevalent in prior art devices.
It will, of course, be understood that
f~r certain uses, it is not necessary that the cold
26.
93sg
~04~3 73
bandage be provided with the outer covering or strip
as shown. For example, the outer strip or covering
can be eliminated when the cold bandage is to be
used with conventional gauze or other type coverings.
Thus referring to Fig. 4, where like parts are
designated by like reference numerals, and where
the choice of materials and constructional details
can be the same as those utilized in the device
of Fig. 1~ it will be seen that the outer covering
has been eliminated together with the release strips.
If désired, however, release strips can be added
and their point of attachment can be at the ends
of the cold bandage.
The term "valvular" as used throughout
the specification and in the claims i~ intended
to refer to apertures in the top sheet which are
capable of opening to permit passage of liquid
under certain circumstances and reclosing to retard
pa~sage of liquid under certain other circumstances.
The term "dimples" are employed to characterize
the depressed areas and mean the depressed areas across
the surface of the top sheet which extend below (or
above) the plane of the top sheet and which are
fabricated in a manner such that there is substantially
no breaking, melting or cutting of the top sheet during
or after fabrication in a manner which would hinder
the controlled passage of liquid to the absorbent pad.
27.
935 9
lQ4t;373
It will also be understood that while the
present invention has been set forth in some detail and
descr~bed with particularity, it is susceptible to
changes, modifications and alterations without departing
from the scope and spirit of the invention as defined
in the appended claims. For example, although the
cold bandage has been shown as having a generally
rectangular configuration, it will, of course, be
understood that it can be circular, eliptical,
diamond shapet or of any other desired practical
configuration.
28.
