U.S. patent number RE33,353 [Application Number 07/359,833] was granted by the patent office on 1990-09-25 for thin film surgical dressing with delivery system.
This patent grant is currently assigned to Minnesota Mining and Manufacturing Company. Invention is credited to Steven B. Heinecke.
United States Patent |
RE33,353 |
Heinecke |
September 25, 1990 |
**Please see images for:
( Certificate of Correction ) ** |
Thin film surgical dressing with delivery system
Abstract
A pressure sensitive adhesive composite with a delivery system
having particular benefit in application of very thin backings such
as high moisture vapor permeable films widely used as medical
dressings is disclosed. The composite has a backing coated with
adhesive on at least a portion of the backing and liner over the
adhesive. At least one edge of the backing is a delivery strip
which is separable from the remainder of the backing. The liner is
securely adhered to the delivery strip and releaseably adhered to
the remainder of the adhesive coated backing. The bond between the
a liner and the delivery strip is strong enough that the delivery
strip will separate from the remainder of the backing before it
will separate from the liner.
Inventors: |
Heinecke; Steven B. (New
Richmond, WI) |
Assignee: |
Minnesota Mining and Manufacturing
Company (St. Paul, MN)
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Family
ID: |
27000649 |
Appl.
No.: |
07/359,833 |
Filed: |
May 31, 1989 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
695042 |
Jan 24, 1985 |
04598004 |
Jul 1, 1986 |
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Current U.S.
Class: |
428/41.5;
428/131; 428/132; 428/137; 428/192; 428/343; 428/352; 428/354;
428/914; 602/57 |
Current CPC
Class: |
A61F
13/023 (20130101); A61L 15/58 (20130101); A61L
15/58 (20130101); C08L 53/00 (20130101); C08L
39/06 (20130101); C08L 33/14 (20130101); C08L
33/08 (20130101); C08L 33/02 (20130101); A61F
2013/00808 (20130101); A61F 2013/00817 (20130101); A61F
2013/00846 (20130101); A61F 2013/00868 (20130101); A61F
2013/0091 (20130101); A61F 2013/00982 (20130101); Y10T
428/24322 (20150115); Y10T 428/24777 (20150115); Y10T
428/2848 (20150115); Y10T 428/2839 (20150115); Y10T
428/24281 (20150115); Y10T 428/1462 (20150115); Y10T
428/24273 (20150115); Y10T 428/28 (20150115) |
Current International
Class: |
A61F
13/02 (20060101); A61L 15/16 (20060101); A61L
15/58 (20060101); A61F 13/00 (20060101); C09J
007/02 (); A61F 013/02 () |
Field of
Search: |
;428/378,40,914,192,343,136,352,132,137,354,41 ;128/155,156 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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81304905 |
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Oct 1981 |
|
EP |
|
0051935 |
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May 1982 |
|
EP |
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84300752.7 |
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Feb 1984 |
|
EP |
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0120570 |
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Oct 1984 |
|
EP |
|
Primary Examiner: Herbert; Thomas J.
Attorney, Agent or Firm: Sell; Donald M. Kirn; Walter N.
Bjorkman; Dale A.
Claims
What is claimed is:
1. An adhesive composite comprising a backing wherein at least one
edge of the backing is a delivery strip which is separable by
perforations from the remainder of the backing;
a pressure sensitive adhesive coated on at least a portion of one
surface of the backing; and
a liner which is adhered to the delivery strip with sufficient
tenacity to result in separation along the perforations of the
delivery strip from the remainder of the backing before the liner
separates from the delivery strip and which liner is releasably
adhered to the remainder of the backing.Iadd., wherein the liner is
strip coated with releasing agent such that the portion contacting
the delivery strip is free of releasing agent and the portion
contacting the remainder of the film has releasing agent.
.Iaddend.
2. The composite of claim 1 wherein the backing is a polymeric
film.
3. The adhesive composite of claim 2 wherein the adhesive coated
film has moisture/vapor transmission rate of at least 300 g/m.sup.2
/24 hrs/37.degree. C./100-10% RH and the adhesive is
biocompatible.
4. The adhesive composite of claim 3 wherein the film is
transparent. .[.5. The adhesive composite of claim 2 wherein the
liner is strip coated with releasing agent such that the portion
contacting the delivery strip is free of releasing agent and the
portion contacting the remainder of the
film has releasing agent..]. 6. The adhesive composite of claim
.[.5.].
.Iadd.1 .Iaddend.wherein the releasing agent is silicone. 7. The
adhesive composite of claim .[.5.]. .Iadd.1 .Iaddend.wherein the
adhesion of the pressure sensitive adhesive coated on the delivery
strip to the liner is
increased by irradiation. 8. The adhesive composite of claim 7
wherein the pressure sensitive adhesive is a copolymer of
iso-octylacrylate and
acrylamide. 9. The adhesive composite of claim 2 wherein the film
has two delivery strips at opposing edges of the film and the liner
is comprised of at least a first segment and a second segment
wherein the first segment is adhered to one delivery strip and the
second segment is adhered to the
opposing delivery strip. 10. The adhesive composite of claim 2
wherein the film has a delivery strip at one edge and pull tab at
the opposing edge.
. The adhesive composite of claim 10 wherein the pull tab is
releasably adhered to the film with greater tenacity than the
adhesion of releasable
portions of the liner. 12. A method of applying a thin flexible
adhesive coated film to a substrate wherein the film has a delivery
strip along at least one edge thereof which is separable from the
remainder of the film and a liner adhered to the adhesive-coated
surface of the film which liner is adhered to the delivery strip
portion of the film with sufficient tenacity to result in
separation of the delivery strip from the remainder of the film
before the liner-delivery strip bond fails and which is releasably
adhered to the remainder of the film.Iadd., wherein the liner is
strip coated with releasing agent such that the portion contacting
the delivery strip is free of releasing agent and the portion
contacting the remainder of the film has releasing agent,
.Iaddend.comprising:
removing the liner from the substrate contacting surface of
film;
placing the substrate contacting surface in intimate contact with
the skin; and
separating the liner and delivery strip from the film.
Description
FIELD OF INVENTION
The present invention relates to pressure sensitive adhesive (PSA)
composites comprising a backing coated on at least one side with
adhesive. More particularly it relates to a PSA composite having a
delivery system to aid placing the composite on a surface. The
invention is of particular benefit in applications of very thin
films such as the high moisture vapor permeable films widely used
as medical dressings.
BACKGROUND
Although the present invention is useful in any adhesive composite
needing a delivery system, it has particular benefit in connection
with transparent film dressings and surgical drapes. These
dressings and drapes are widely used as a protective layer over a
wound, facilitating healing in a moist environment while acting as
a barrier to liquids and bacteria. Dressings of this type are
available under trade names such as Tegaderm.TM. (3M, St. Paul, MN)
Bioclosure.TM. (Johnson & Johnson, New Brunswick, N.J.) and
Op-Site.TM. T. J. Smith & Nephew, Hull, England). Uniflex.TM.
(Howmedica, Largo, Fla.), U.S. Pat. No. 3,645,835, which is hereby
incorporated by reference, describes one such moisture vapor
permeable, water bacteria impermeable dressing.
The polymeric films used in such dressings are extremely thin,
flimsy, and supple. They are supplied with a releasable protective
liner overlying the adhesive coated surface of the film. When the
liner is removed the adhesive coated film tends to fold and stick
to itself forming wrinkles which render smooth aseptic application
of a dressing or drape to skin very difficult. Various delivery
systems have been proposed to obviate this problem.
One such delivery system utilizes a frame to support the edges of
the film during its application. European Pat. Appln. No. 81 30
4905 describe a composite having a relatively thin polymeric film
which is conformable to animal anatomic surfaces. A pressure
sensitive adhesive is coated to at least a portion of one surface
of the polymeric film. A release liner is attached to the adhesive
coated surface of the film. A second releasable layer or carrier is
attached to the opposing (exposed) surface of the film. This second
releasable layer is attached to the film more tenaciously than the
release liner is adhered to the adhesive side of the film and is
preferably a frame adhered to the periphery of the film. In use the
releasable layer stays with the film until the film is affixed to
the substrate, at which time it may be removed.
Another delivery system is utilized in the Op-Site.TM. dressing. In
that dressing the film is provided with a pull tab along one edge
of the film. The releasable liner is removed by peeling the liner
and the pull tab away from each other. The pictorial instructions
supplied with the product suggest that the dressing should be
applied by grasping the pull tab and the releasable liner which has
been partially removed and then placing the film on the intended
site. Thereafter the releasable liner is completely peeled off and
the dressing smoothed to the skin surface. The pull tab can be left
in place or, in an alternative embodiment, the pull tab and the
film to which it is adhered are removed from the remainder of the
dressing by separation along perforations provided for this
purpose. U.S. Pat. No. 4,413,621 describes such a dressing.
A third delivery system is described in European Pat. Appln. No. 84
30 0752.7 (publication No. 0,120,570). That application describes a
wound dressing made of a film that is coated on one face with a
biocompatible adhesive. One or more liner sheets are releasably
adhered to the adhesive coated surface. Release retarding means are
provided along one edge or a pair of opposed edges of the dressing
to require a greater force to separate the layers (film, adhesive,
and liner) at the edge or edges than at the remainder of the
contact area. The release retarding means may be a thicker strip of
the polymeric film, a stiffer piece of film adhered to the film at
its edges, a strip of liner backing wrapped around the edge of the
film and adhered to the surface of the film, or a strip attached to
the exposed surfaces of both the film and the backing.
Alternatively an adhesive having greater tenacity than the quick
release adhesion of the biocompatible adhesive for the liner may be
used.
SUMMARY OF THE INVENTION
The adhesive composite of the present invention has three layers--a
backing, a pressure sensitive adhesive layer coated on at least a
portion of one surface of the backing, and a liner over the
adhesive. At least one edge of the backing is a delivery strip
which is separable from the remainder of the backing. The liner is
securely adhered to the delivery strip portion of the
adhesive-coated backing and it is releasably adhered to the
remaining surface of the adhesive-coated backing. The bond between
the liner and the delivery strip is strong enough that the delivery
strip will separate from the remainder of the backing before it
will separate from the liner.
The backing is preferably a film provided with perforations to
define the delivery strip edge. In use pulling firmly on the liner
which is adhered to the delivery strip of the film but which has
been peeled back from the remaining areas of the film will cause
the film to tear along the perforations.
The preferred adhesive coated film is permeable to moisture and
vapor and should transmit moisture vapor at a rate of at least 300
g/m.sup.2 /24 Hrs/37.degree. C./100-10% RH. Preferably the adhesive
coated film transmits moisture vapor at a rate of at least 700
g/m.sup.2 /24 Hrs/37.degree. C./100-10% RH. When a high moisture
vapor permeable film is used the adhesive is preferably
biocompatible. Most preferably the PSA composite comprises high
moisture vapor permeable film, a biocompatible adhesive and is
transparent.
The preferred method of securely attaching the liner to the
delivery strip entails use of a conventional liner material which
has been strip coated with a releasing agent, e.g. silicone. In the
preferred embodiment the liner is left free of any releasing agent
along the strip that contacts the delivery strip of the film. The
remaining surfaces of the liner, that is those areas that will
releasably contact the PSA coated film, are coated with the
releasing agent. In a composite of this type, the adhesion of the
liner to the pressure sensitive adhesive coated on the delivery
strip may be increased by irradiation. Adhesives which increase
their adhesion upon irradiation are known in the art. When the
adhesive is a copolymer of iso-octylacrylate and acrylamide
irradiation to increase adhesion can take place simultaneously with
sterilization when gamma irradiation is used.
The adhesive composite of the present invention may be constructed
with two delivery strips at opposing edges of the film. In this
embodiment the liner is comprised of at least first and second
segments wherein the first segment is adhered to one delivery strip
and the second segment is adhered to the opposing delivery strip.
Preferably in this embodiment the two segments of the liner are
releasably adhered to the adhesive coated film and meet near the
center of the film. They are preferably provided with an extension
of liner material to facilitate peeling of the liner segments.
These extensions may be integral with the liner or separate pull
handles adhered to the liner. They may be folded in a conventional
"J" fold. Alternatively one piece of liner can be folded in a "J"
fold while the continuing surface of the second piece of liner
extends beyond the "J" fold of the first.
In an alternative embodiment the film has one delivery strip at one
edge and the liner extends across the entire adhesive-coated
surface of the film. In this embodiment the film is preferably
provided with a pull tab at the edge opposing the delivery strip
edge of the film. In use the pull tab may be left in place after
application of the film, or the pull tab may be releasably adhered
to the film and removed after application of the film. In this
latter alternative the pull tab should adhere to the film with
greater tenacity than the adhesion of the releasable portions of
the liner.
In the method of this invention a thin flexible adhesive coated
film is applied to a substrate wherein the film has a delivery
strip along at least one edge thereof which strip is a separable
from the remainder of the film and a liner is adhered to the
adhesive coated surface of the film which liner is adhered to the
delivery strip of the film with sufficient tenacity to result in
separation of the delivery strip from the remainder of the film
before the liner-delivery strip bond fails and which liner is
releasably adhered to the skin contacting surface of the film. The
composite is applied by removing the liner from the substrate
contacting surface of the film, placing the substrate contacting
surface of the film into intimate contact with the intended site,
and thereafter separating the liner and delivery strip from the
film.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of the adhesive composite of the
present invention;
FIG. 2 is a perspective view of the adhesive composite of the
present invention;
FIG. 3 is a plan view of the adhesive composite of the present
invention showing the liner surface;
FIG. 4 is a cross section of view of the present invention showing
separation of the releasable portions of the liner from an adhesive
coated film;
FIG. 5 is a cross section view of the present invention showing
application of an adhesive coated film to a substrate.
FIG. 6 is a perspective view of an alternative embodiment adhesive
composite showing a composite with a unitary liner and a pull tab
on the film.
DETAILED DESCRIPTION
The delivery system of the present invention is useful in
connection with any backing having a pressure sensitive adhesive
coated on to it. Representative backings include nonwoven fibrous
webs, fibrous film webs, knits, and other familiar backing
materials. The preferred backing materials are polymeric films. The
invention is particularly useful in PSA composites having high
moisture vapor permeable films. U.S. Pat. No. 3,645,835 describes a
method of making such a high vapor/moisture permeable film and a
method for testing its permeability.
The film is also preferably conformable to body surfaces. Generally
the films are from 12 to 25 microns thick. Conformability is
somewhat dependent on thickness, thus the thinner the film the more
conformable it is. In the preferred embodiment the films used in
the device of the present invention are conformable to animal
anatomical surfaces. This means that when the film is applied to an
animal anatomical surface it conforms to the surface even when the
surface is moved. The preferred films are conformable to animal
anatomical joints. When the joint is flexed and then returned to
its unflexed position, the film stretches to accommodate the
flexion of the joint but is resilient enough to continue to conform
to the joint when the joint is returned to its unflexed condition.
A measure of conformability is the F.sub.10 modulus. The F.sub.10
modulus should be no greater than about 1 pound (454 grams) and
preferably less than about 0.8 pounds (363 grams). In the preferred
embodiments of wound dressings and drapes, films which have
F.sub.10 moduli upwards of 2.5 pounds (1135 grams) may be used.
However, as the F.sub.10 modulus increases the conformability
decreases and the ability of the film to perform comfortably as
medical dressings likewise decreases.
F.sub.10 modulus as referred to herein is effectively determined
using an Instron Unit Model 1102 from Instron Corp., 2500
Washington Street, Canton, Mass. The cross-head speed of the
Instron is set at ten inches per minute and the chart speed is set
at ten inches (25.4 cm) per minute. The gauge length is set at two
inches (5 cm) with the test sample cut to test a one-inch width
(2.54 cm).
Examples of polymers which are suitable for use as wound dressing
films in the present invention include polyurethane, elastomeric
polyester such as DuPont "Hytrel" polyester elastomer (Wilmington,
Delaware), polyethylene, blends of polyurethane and polyester,
chlorinated polyethylene, styrene/butadiene block copolymers such
as "Kraton" brand thermoplastic rubber (Shell Chemical Company,
Houston Tex.), and polyvinyl chloride.
Particularly preferred films are polyurethane and elastomeric
polyester films. These films combine the desirable properties of
resiliency, high moisture vapor permeability and transparency.
The preferred adhesives which can be used in the preferred wound
dressing embodiment are the normal adhesives which are applied to
the skin such as those described in U.S. Pat. No. Re. 24,906,
particularly a copolymer of 96% iso-octyl acrylate units and 4%
acrylamide units and a copolymer of 94% iso-octyl acrylate units
and 6% acrylic acid units. Other useful adhesives are those
described in U.S. Pat. No. 3,389,827 which comprise block
copolymers having three or more polymer block structures having a
general configuration --A--B--A-- wherein each A is a thermoplastic
polymer block with a glass transition temperature above room
temperature (i.e., above about 20.degree. C.) having an average
molecular weight between about 5000 and 125,000 and B is a polymer
block of a conjugated diene having an average molecular weight
between about 15,000 and 250,000. Additional examples of useful
adhesive are iso-octyl acrylate/n-vinyl pyrrolidone copolymer
adhesives and crosslinked acrylate adhesives such as for example
those described in U.S. Pat. No. 4,112,213. Inclusion in the
adhesive of medicaments or antimicrobial agents such as iodine is
useful for enhancing wound healing and preventing infection. U.S.
Pat. Nos. 4,310,509 and 4,323,557 describe antimicrobial
adhesives.
The liner is preferably strip coated with a releasing agent applied
to the liner only in the areas which will contact the substrate
(e.g. the skin contacting surface of the film). No release agent is
applied to the strips which will contact the delivery strips of the
film. Examples of liners suitable for use in the present invention
are strip coated liners made of kraft papers, polyethylene,
polypropylene or polyester, and are coated with releasing agents
such as fluorochemicals or silicone. U.S. Pat. No. 4,472,480
describes low surface energy perfluorochemical liners. The
preferred liners are silicone coated release papers, polyolefin
films, or polyester films. Examples of the silicone coated release
papers are Polyslik.TM. silicone release papers supplied by H. P.
Smith Co., Chicago, Ill. and silicone coated papers supplied by
Daubert Chemical Co., Dixon, Ill. The preferred liner is
75-W-89-SPT3A-Zoned/PST3A paper available from Schoeller Release
Products, West Chicago, Ill. This products is a polyethylene coated
kraft paper bearing an electron beam cured silicone surface. The
silicone is coated in the areas which are releasably adhered to the
substrate (e.g., skin) contacting surface of the film and uncoated
in the areas which are adhered to the delivery strips of the
film.
Other combinations of adhesive and liner are feasible. Those
skilled in the art are familiar with process of testing a new
adhesive against different liners, or a new liner against different
adhesives in order to arrive at the combination of qualities
desired in the final product. Handbook of Pressure-Sensitive
Adhesive Technology, Chapter 18 "Silicone Release Coatings"Van
Nostrand-Reinhold, 1982, pp. 384-403, which is hereby incorporated
by reference describes the considerations pertinent to selection of
a silicone release liner. U.S. Pat. No. 4,472,480 which is hereby
incorporated by reference describes considerations pertinent to
selection of a perfluoropolyether liner. In the preferred wound
dressing embodiment of the present invention, the choice of
adhesive is limited to those that are safe to use on skin, and
preferably to those that are of the class known as hypollergenic.
The preferred polyacrylates are adhesives of this class. Liners are
available from a variety of manufacturers in a wide variety of
proprietary formulations. One normally tests these in simulated use
conditions against an adhesive of choice to arrive at a product
with the desired release characteristics.
In the present invention, a parameter in addition to selection of
the adhesive, the liner, and the method of fixation can be varied
to achieve the desired tenacity of adhesion of the liner to the
delivery strip. This factor is the perforations or line of weakness
put into the film to allow breakage of the delivery strip from the
remainder of the film. For example, after the combination of
adhesive and liner which give the desired low peel force when
removing the liner is selected a pattern of perforations is
developed, which is found to hold when the film is gently held taut
while being applied, but which breaks when a slightly greater pull
is applied by the user. Too few perforations will result in a film
which stretches, deforms, and tears unevenly. Too many or too large
perforations will yield a film which tears to readily.
FIG. 1 shows the preferred embodiment of the present invention.
This embodiment is a wound dressing 10 shown as received by the
user. For clarity, protective and sterile outer wrappings are not
shown. The dressing is made of a thin transparent, polymeric film
11 which is moisture vapor permeable, liquid and bacteria
impermeable such as a polyester or polyurethane film. A coating of
biocompatible pressure sensitive adhesive 20 such as non-allergenic
polyacrylate bioadhesive covers the lower, skin contacting surface
of the film. A liner in two segments 31 and 32 covers the adhesive.
The two segments meet near the center of the dressing and are
provided with integral extensions 33 and 34 which serve as handles
to be grasped by the user when removing the liner segments. One
extension 33 is virtually flat; the other extension 34 is shown
folded in a "J" pattern. At the two opposed edges of the film 11
are delivery strips 12 and 13. The delivery strips 12 and 13 are
defined by the edges of the film and the perforation lines 14 and
15. The liner segments 31 and 32 are firmly adhered to the adhesive
coated delivery strips 12 and 13. This affixing may be accomplished
in several ways. The fixation may be mechanical. A heat sea may be
used. Another way is to have the liner strip coated with a release
agent (e.g. silicone). As best shown in FIG. 3, therefore liner 31
is coated with release agent in the portion defined by lines 35 and
36. The remaining portion of the liner (defined by lines 35 and 37)
is left free of release agent. The portion which has no release
agent is firmly adhered to the delivery strip 12, preferably by
increasing the strength of adhesion between the adhesive coated
delivery strip 12 and the liner by irradiation. In the preferred
embodiment where the adhesive is a copolymer of iso-octylacrylate
and acrylamide, the bond between the delivery strip and the liner
may be conveniently increased during sterilization of the product
with gamma irradiation. The bond formed between the liner and the
delivery strip is stronger than the line of weakness (e.g.
perforations 14 and 15 best shown in FIG. 2) which permits
separation of the delivery strip from the skin contacting surface
of the film.
FIG. 4 shows the dressing of FIG. 1 being prepared for application
to a wound. For ease of illustration the dressing has been folded
around line A--A shown in FIGS. 2 and 3. With the film 11 being
extremely flexible and bent as shown in FIG. 4, and where the liner
is chosen so as to have low adhesion of the liner to the film,
liner segment 31 begins to peel off the adhesive coated film. When
a gentle pull is applied to liner segment 31 as indicated by arrow
40, this peeling will continue until the entire segment 31 is
peeled from the film except for the portion defined by lines 35 and
37 which is securely adhered to the delivery strip 12. With
continued gentle pulling of the liner 31 the film will unfold and
the other segment of the liner 32 will peel off the film until the
condition shown in FIG. 5 is reached. Alternatively, the liner
segments 31 and 32 may be peeled from the adhesive coated film
simultaneously. When this procedure is employed the condition shown
in FIG. 5 is similarly reached.
FIG. 5 shows the dressing 10 with the adhesive coated surface
positioned for application the wound. Further increasing the
tension applied to the skin 50 of a patient over a wound 51. The
dressing is made taut by gentle tension applied in directions 41
and 42. It is then smoothed down onto the wound. Further increasing
the tension applied to the film by pulling the liner segments will
cause the film to break along perforation lines 14 and 15. After
the film tears along the perforations 14 and 15 the film lies flat
on the skin and, because of its physical characteristics, forms a
homogeneous and unobtrusive dressing which conforms well to the
contours of the skin. The liner and delivery strips are
discarded.
FIG. 6 shows an alternative embodiment of the present invention.
This embodiment, shown as a wound dressing 100, has a liner 300
formed as one segment. The dressing is made of a thin transparent,
polymeric film 110 which is moisture vapor permeable and liquid and
bacteria impermeable. A coating of biocompatible pressure sensitive
adhesive 200 such as polyacrylate bioadhesive covers the lower skin
contacting surface of the film. A liner 300 covers the adhesive. At
one edge of the film is a delivery strip 120. The delivery strip is
defined by the edge of the film and perforation line 140. At the
opposite end of the film 110 is a pull tab 170. The pull tab 170
may be an extension of the film having no adhesive and without
perforations, or it may have a perforation line 171 so that it can
be removed after application of the dressing to the skin. The liner
is firmly adhered to the delivery strip. The remaining portions of
the liner is releasably adhered to the remainder of the film. To
apply this dressing the user grasps the pull tab 170 and begins to
peel the liner 300. Then holding the pull tab and liner the
releasable portion of the liner is removed and the film is placed
onto the intended site and smoothed. At this time a firm tug will
cause the delivery strip to separate from the remainder of the
film.
The composite of the present invention may be made by conventional
techniques (e.g. extrusion, solvent casting, calendering, and
laminating and the like) which are familiar to those skilled in the
art. (See Modern Plastics Encyclopedia McGraw Hill, 1984-85;
Coating and Laminating Machines, Weiss Converting Technology Co.,
1977.) The method of making a composite is further exemplified by
the following non limiting example.
EXAMPLE
Twenty five grams per square meter of an adhesive prepared in
accordance with U.S. Pat. No. Re. 24,906, which is incorporated by
reference, comprising of copolymer of 96% units of isooctylacrylate
and 4% units acrylamide was applied to a release liner of 78 pounds
(35412 grams) bleached, one-side coated, polyethylene and silicone
paper (Polyslik S-8053, H. P. Smith, Chicago, Ill. utilizing a
standard horizontal knife coater. A 1.1 mil (28 micron) film of
"Estane 58309NAT022 polyurethane resin (B. F. Goodrich, Cleveland,
Ohio) was laminated to the adhesive surface. This material was then
slit to proper width to make the size dressing desired. The
adhesive/film laminate was then removed from the S-8053 release
liner and relaminated to the J folded and flat finished product
release liner (75W-89SPT3A-Zoned/PST3A, Schoeller Release Products,
West Chicago, Ill.) to form a roll of double liner bandage stock
with non-silicone strip or each edge of roll. The perforating and
slitting of the dressing to size were performed using a
die-cutting/printing machine (Model 813, Series KZY223, Mark Andy,
St. Louis, Mo.).
The foregoing description has been directed to particular preferred
embodiments for purposes of illustration and explanation. Those
skilled in the art will appreciate that many modifications will be
possible without departing from the spirit of the invention. For
example the composite may further comprise a gauze dressing or the
pressure sensitive adhesive may be pattern coated to increase
moisture vapor transmission rate and decrease pain upon removal of
a dressing. The following claims are intended to be interpreted to
embrace all such modifications and variations.
* * * * *