U.S. patent application number 13/383048 was filed with the patent office on 2012-05-03 for water-vapor permeable adhesive bandages.
Invention is credited to Christian Hausen, Michael Horstmann, Tobias Kleudgen, Karin Ludwig, Patrick Mohr.
Application Number | 20120109033 13/383048 |
Document ID | / |
Family ID | 43303903 |
Filed Date | 2012-05-03 |
United States Patent
Application |
20120109033 |
Kind Code |
A1 |
Horstmann; Michael ; et
al. |
May 3, 2012 |
WATER-VAPOR PERMEABLE ADHESIVE BANDAGES
Abstract
The present invention relates to adhesive bandages provided with
a water-vapor permeable back layer and an adhesive layer, in which
the adhesive layer includes 10 weight percent of a disperse
internal phase of hydrophilic particles that are water-swellable in
an outer phase that includes at least 10 weight percent of a
styrene block copolymer and at least 20 weight percent of an ester
gum of the colophony, and that can further contain at least one
anti-virus substance.
Inventors: |
Horstmann; Michael;
(Neuwied, DE) ; Hausen; Christian; (Vettelschoss,
DE) ; Mohr; Patrick; (Bad Breisig, DE) ;
Ludwig; Karin; (Datzeroth, DE) ; Kleudgen;
Tobias; (Ettringen, DE) |
Family ID: |
43303903 |
Appl. No.: |
13/383048 |
Filed: |
July 3, 2010 |
PCT Filed: |
July 3, 2010 |
PCT NO: |
PCT/EP2010/004029 |
371 Date: |
January 9, 2012 |
Current U.S.
Class: |
602/41 |
Current CPC
Class: |
A61L 2300/408 20130101;
A61L 15/44 20130101; A61L 2300/608 20130101; A61L 15/24 20130101;
A61L 15/58 20130101; A61L 15/24 20130101; C08L 25/04 20130101 |
Class at
Publication: |
602/41 |
International
Class: |
A61F 13/00 20060101
A61F013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 14, 2009 |
DE |
10 2009 032 866.1 |
Nov 12, 2009 |
DE |
10 2009 052 943.8 |
Claims
1. A skin plaster comprising a water-vapor-permeable back layer and
an adhesive layer which comprises 10% by weight of a disperse inner
phase of hydrophilic, water-swellable particles in an outer phase
comprising at least 10% by weight of a styrene block copolymer and
at least 20% by weight of an ester resin of colophony.
2. The skin plaster as claimed in claim 1, wherein the material for
the back layer is selected from the group which comprises
polyethylene films, polypropylene films, polyvinyl chloride films,
polyether amide films, polyamide films, polyester films, ethylene
vinyl acetate films, woven fabrics, knitted fabrics, foams and
polyurethane films.
3. The skin plaster as claimed in claim 1, wherein the back layer
is microporous or perforated.
4. The skin plaster as claimed in claim 1, wherein the styrene
block copolymer is selected from the group which consists of
styrene-olefin-styrene block copolymers.
5. The skin plaster as claimed in claim 4, wherein the olefin block
is based on one or more compounds which is/are selected from the
group which comprises isoprene, butadiene, ethylene, butylene,
polyisobutylene.
6. The skin plaster as claimed in claim 1, wherein the styrene
block copolymer is a styrene-isoprene-styrene block copolymer.
7. The skin plaster as claimed in claim 1, wherein the ester resin
of colophony is selected from the group which comprises esters of
colophony with glycerol, esters of colophony with pentaerythritol
and esters of colophony with glycols.
8. The skin plaster as claimed in claim 1, wherein the ester resin
of colophony is an ester of one or more resin acids.
9. The skin plaster as claimed in claim 1, wherein the hydrophilic,
water-swellable particles are hydrocolloids.
10. The skin plaster as claimed in claim 1, wherein the
hydrophilic, water-swellable particles consist of a material which
is selected from the group of compounds which consists of starch
flour, celluloses, chitosan, pectin, gum arabic, guar seed flour,
carob seed flour, agar, carrageenan, alginates, gelatin,
caseinates, dextrins, xanthan, or synthetic polymers selected from
polyacrylic acids, polyvinyl alcohols, polyvinyl acetates,
polyhydroxyalkyl acrylates, polyhydroxyalkyl methacrylates,
polyacrylamides, polystyrenesulfonates, polyvinylpyrrolidones,
polyglycols, copolymers, graft copolymers and mixtures of said
polymers.
11. The skin plaster as claimed in claim 1, wherein the adhesive
layer is not thicker than 300 .mu.m.
12. The skin plaster as claimed in claim 1, wherein the skin
plaster exhibits a water vapor permeability in a period of 24 hours
is at least 50 g/m.sup.2.
13. The skin plaster as claimed in claim 1, wherein the skin
plaster has an absorption capacity of at least 40 g/m.sup.2/6
h.
14. The skin plaster as claimed in claim 1, wherein the skin
plaster additionally has an absorbent covering.
15. The skin plaster as claimed in claim 1, wherein the skin
plaster additionally has a single-part or multi-part, detachable
protective layer or protective film which completely or partly
covers the adhesive layer on its surface facing the back layer.
16. The skin plaster as claimed in claim 1, wherein the skin
plaster comprises at least one antiviral active ingredient.
17. The skin plaster as claimed in claim 16, wherein the antiviral
active ingredient is selected from the group which comprises
aciclovir, valacyclovir, penciclovir, famciclovir, brivudine,
adenine arabinoside, phosphonoformic acid, silicic acid,
n-docosanol and idoxuridine.
18. The skin plaster as claimed in claim 16, wherein the content of
active ingredient(s) is 0.1 to 20% by weight, based on the mass of
the adhesive layer.
19. The skin plaster as claimed in claim 8, wherein the ester of
one or more resin acids is an ester of abietic acid and/or an ester
of pimaric acid.
20. The skin plaster as claimed in claim 10, wherein the compound
is cellulose and the cellulose is carboxymethylcellulose.
21. The skin plaster as claimed in claim 11, wherein the adhesive
layer s not thicker than 200 .mu.m.
22. The skin plaster as claimed in claim 11, wherein the adhesive
layer is not thicker than 150 .mu.m.
23. The skin plaster as claimed in claim 11, wherein the adhesive
layer is not thicker than 100 .mu.m.
24. The skin plaster as claimed in claim 12, wherein the water
vapor permeability in a period of 24 hours is at least 80
g/m.sup.2.
25. The skin plaster as claimed in claim 12, wherein the water
vapor permeability in a period of 24 hours is at least 100
g/m.sup.2.
26. The skin plaster as claimed in claim 13, wherein the absorption
capacity of the skin plaster is at least 50 g/m.sup.2/6 h.
27. The skin plaster as claimed in claim 13, wherein the absorption
capacity of the skin plaster is at least 60 g/m.sup.2/6 h.
28. The skin plaster as claimed in claim 13, wherein the absorption
capacity of the skin plaster is at least 70 g/m.sup.2/6 h.
29. The skin plaster as claimed in claim 18, wherein the content of
active ingredient(s) is 1.0 to 10% by weight, based on the mass of
the adhesive layer.
Description
[0001] The present invention relates to skin plasters, i.e.
plasters for covering an area of the surface of a living being,
which can adhere to the skin, as in patent application DE 10 2009
032 866.1.
[0002] The invention relates in particular to skin plasters with a
high water-vapor permeability.
[0003] Usually, plasters for treating or preventing wounds or
pressure points comprise a back layer and an adhesive layer. The
back layer can be occlusive, i.e. impermeable to water vapor, and,
as a result, cause an increase in undesired moisture underneath
(=in the area of the application site of) the skin plaster, which
leads to skin irritations and shortened wearing time.
[0004] There have been numerous attempts to develop skin plasters
with an increased water-vapor permeability which allow an
evaporation of moisture that arises on the surface of the skin
through the skin plaster. As a result, an undesired accumulation of
moisture and the associated detachment of the skin plaster or
increase in the level of bacteria underneath the skin plaster can
be avoided.
[0005] The problem for the person skilled in the art when
developing water-vapor-permeable skin plasters consists in
providing a skin-compatible pressure-sensitive adhesive which at
the same time has a high adhesive power and a high water-vapor
permeability and/o3r water-absorption capacity.
[0006] The prior art discloses, for example, water-containing
adhesives which are based virtually entirely on water-soluble
polymers. However, the adhesive power of the water-containing
adhesives is perceived as inadequate. Moreover, skin plasters with
an adhesive layer based on water-soluble polymers come off after a
wearing time of a few hours because the adhesive layer dries out
and, in so doing, loses its adhesive power.
[0007] The prior art also describes hydrocolloid adhesive masses
for producing non-occlusive skin plasters. Classic hydrocolloid
adhesive masses are traditionally produced from vegetable gums with
the addition of further natural products and are as a rule applied
in a thick layer. Such masses are used for example as edge adhesive
masses for colostomy bags.
[0008] Particularly suitable hydrocolloid adhesive masses are
described in U.S. Pat. No. 3,339,546, in particular an adhesive
mass comprising polyisobutylenes and one or more hydrocolloids
which can swell in aqueous liquids.
[0009] Further examples of hydrocolloid adhesive masses are known
from U.S. Pat. No. 4,231,369 and U.S. Pat. No. 4,367,632.
[0010] U.S. Pat. No. 4,231,369 discloses a sealing material for
colostomy bags, comprising at least one crosslinked elastomer as
basis for an external, continuous phase in which at least one
hydrocolloid is dispersed. The elastomer can be a
styrene-olefin-styrene block copolymer or an ethylene-propylene
block copolymer. In addition, the outer phase comprises a tackifier
from the group of polymers and copolymers of dicyclopentadiene,
alpha-pinene or beta-pinene.
[0011] U.S. Pat. No. 4,367,732 relates to skin plasters consisting
of an elastic film and a weakly elastic adhesive. This adhesive
comprises:
[0012] (I) a continuous phase comprising [0013] (a) a physically
crosslinked elastomer in the form of a styrene-isoprene-styrene
block copolymer or ethylene-propylene block copolymer, [0014] (b) a
hydrocarbon resin in the form of a polymer or copolymer of
cyclopentadiene, dicyclopentadiene, alpha-pinene and/or
beta-pinene, [0015] (c) an antioxidant, [0016] (d) optionally an
oil extender consisting of one or more mineral oils, and [0017] (e)
optionally a plasticizer, which is polar to the elastomer, for
example an ester of a polyethylene glycol or polypropylene glycol,
or an ester of a di- or polybasic carboxylic acid with a preferably
aliphatic alcohol, and
[0018] (II) a phase dispersed in the continuous phase and
comprising one or more water-swellable hydrocolloids.
[0019] The elastic film which forms the back layer should be
water-impermeable, preference being given to an elastic,
water-impermeable polyurethane film.
[0020] The adhesive in the case of the skin plaster can be present
in the form of a relatively thin layer, which has a thickness of
0.25 to 3 mm and preferably a thickness of about 1.1 mm.
[0021] In more recent times, very thin skin plasters with and
without the addition of water-swellable particles have also been
developed. For example, WO 2006/130461 A1 discloses thin,
non-occlusive skin plasters for treating virus-induced lesions.
These skin plasters comprise a back layer and an adhesive layer
which is essentially free from hydrocolloid particles. The skin
plasters reportedly have a thickness of only 10 to 1500 .mu.m, it
being described how the adhesive layer can be between 20 and 200
.mu.m in thickness.
[0022] WO 2005/051333 A1 describes skin plasters which have a
water-vapor-permeable back layer and a skin-friendly,
hydrocolloid-particle-containing adhesive layer. The thickness of
the adhesive layer of these skin plasters is at least in the edge
region of the skin plaster 20 to 300 .mu.m, the water-vapor
permeability of the skin plasters is 200 to 1000 g/m.sup.2 and the
moisture absorption of the skin plaster is 40 to 600 g/m.sup.2/6
h.
[0023] The plasters known from the prior art, however, do not have
a satisfactory adhesive power coupled with adequately high
water-vapor permeability.
[0024] The object of the present invention was therefore to provide
skin plasters which have a good adhesive power coupled with high
water-vapor permeability.
[0025] Surprisingly, the object is achieved by a skin plaster which
comprises a back layer made of a water-vapor-permeable material,
preferably a film of polyurethane, and an adhesive layer which
comprises 10% by weight of a disperse inner phase of hydrophilic,
water-swellable particles in an external phase comprising at least
10% by weight of a styrene block copolymer and at least 20% by
weight of an ester resin of colophony.
[0026] The back layer of the skin plaster according to the
invention is water-vapor permeable. Materials that are suitable in
principle for a back layer are polyolefin films, for example made
of polyethylene or polypropylene, polyvinyl chloride films,
polyether amide films, polyamide films, polyester films, ethylene
vinyl acetate films, woven fabrics, knitted fabrics, foams and
polyurethane films. Within the context of the invention, the term
"films" is used both for polymer films and for polymer foils.
[0027] The back layer can be monolithic provided it has the
required water-vapor permeability. However, the back layer can also
be microporous or perforated in order to make an otherwise
water-vapor-impermeable polymer film water-vapor-permeable.
[0028] Preferably, the back layer is water-impermeable, but
water-vapor-permeable.
[0029] The preferred material for the back layer is a low-friction,
flexible polymer film. Particularly preferred materials for the
back layer are water-vapor-permeable polyurethane films.
[0030] The back layer has a suitable thickness for the intended
use. The use of thinner back layers leads to skin plasters with
better extensibility and ability to adapt to the surface of the
body.
[0031] Preferably, the back layer has a thickness of less than 30
.mu.m, particularly preferably of less than 20 .mu.m and very
particularly preferably of less than 18 .mu.m. The back layer can
even have a thickness of less than 15 .mu.m, for example a
thickness of 12 .mu.m.
[0032] The water-vapor permeability of the back layer is at least
200 g/24 hours, preferably at least 800 g/24 hours. The water-vapor
permeability is up to 1300 g/24 hours, preferably up to 6000 g/24
hours.
[0033] The adhesive layer of the skin plaster according to the
invention consists of an adhesive which has a continuous outer
phase and an inner phase dispersed in this outer phase. The
continuous outer phase comprises at least 10% by weight of a
styrene block copolymer and at least 20% by weight of an ester
resin of colophony. The weight percentage data refers to the mass
of the adhesive. The inner phase consists of hydrophilic,
water-swellable particles and constitutes at least 10% by weight of
the adhesive mass.
[0034] The adhesive for the adhesive layer of the skin plasters
according to the invention comprises a styrene block copolymer. The
styrene block copolymer is preferably an elastomer from the group
of styrene-olefin-styrene block copolymers. The olefin block can be
based on isoprene, butadiene, other short-chain alkadienes or
alkanes, such as, for example, mixtures of ethylene and butylene,
or polyisobutylene, and also of combinations of these compounds.
Styrene block copolymers that are particularly preferred for the
outer phase are styrene-isoprene-styrene block copolymers.
[0035] The adhesive for the adhesive layer of the skin plasters
according to the invention comprises at least one ester resin of
colophony.
[0036] Colophony is a natural resin which is obtained from the
balsam of conifers. It is the non-distillable, solid residue of
conifer balsam. The distillate is referred to as terpentine oil and
comprises alpha-pinene and beta-pinene as main constituents.
Colophony consists of a mixture of resin acids and terpenes. The
main constituent of colophony is easy-to-oxidize resin acids such
as abietic acid and pimaric acid. By reacting the resin acids of
colophony with polyols such as pentaerythritol, glycerol or
glycols, the so-called colophony esters are obtained, which are
also referred to as ester resins of colophony.
[0037] Consequently, within the context of the present invention,
the term "ester resins of colophony" also includes esters of the
resin acids, in particular esters of abietic acid and/or of pimaric
acid, to which expressly also the esters with pentaerythritol,
glycerol or glycols belong.
[0038] The preparation of colophony esters usually takes place by
batch processes in the molten state at very high temperatures (250
to 300.degree. C.).
[0039] Preferably, the ester resins of colophony for the skin
plasters according to the invention are esters of glycerol, esters
of pentaerythritol or mixtures of these esters.
[0040] The adhesive for the adhesive layer of the skin plasters
according to the invention comprises hydrophilic, water-swellable
particles. Preferably, the hydrophilic, water-swellable particles
are hydrocolloid particles.
[0041] "Hydrocolloids" are understood as meaning a large group of
polysaccharides and proteins which dissolve in water as colloids
and display a high ability for gel formation. Virtually all
hydrocolloids are of natural origin. They are either naturally
occurring hydrophilic polymers or their chemically modified
variants. The hydrocolloids include, for example, starch,
celluloses such as carboxymethylcellulose, chitosan, pectins, gum
arabic, guar seed flour, carob seed flour, agar, carrageenan,
alginates, gelatin, caseinates, dextrins and xanthan.
[0042] For the hydrophilic, water-swellable particles, synthetic
polymers of the same or different monomers are also suitable.
Suitable hydrophilic, water-swellable particles can consist, for
example, of polyacrylic acid, polyvinyl alcohol, polyvinyl acetate,
polyhydroxyalkyl acrylates, polyhydroxyalkyl methacrylates,
polyacrylamides, polystyrene sulfonates, polyvinylpyrrolidone,
polyglycols, copolymers, graft copolymers and mixtures of said
polymers.
[0043] The hydrophilic, water-swellable particles have an average
size of less than 125 .mu.m, they are preferably smaller than 100
.mu.m, particularly preferably smaller than 75 .mu.m and very
particularly preferably smaller than 50 .mu.m.
[0044] By virtue of the content of hydrophilic water-swellable
particles in the adhesive layer, with the skin plasters according
to the invention it is possible to achieve good conditions for a
moist wound healing.
[0045] The adhesive layer of the skin plaster according to the
invention can be relatively thick, for example up to 1 mm,
preferably up to 3 mm and particularly preferably up to 5 mm.
[0046] According to preferred embodiments, however, the adhesive
layer of the skin plasters according to the invention is a
comparatively thin layer which is not thicker than 300 .mu.m,
preferably not thicker than 200 .mu.m, particularly preferably not
thicker than 150 .mu.m and very particularly preferably not thicker
than 100 .mu.m. The lower limit which can be given for the
thickness of the adhesive layer is 25 .mu.m, preferably 30 .mu.m.
Thin adhesive layers are preferred because the resulting skin
plaster is also thin and therefore more flexible.
[0047] The thickness of the adhesive layer of the skin plaster
according to the invention can be essentially constant over the
entire surface of the skin plaster. In preferred embodiments,
however, the adhesive layer is thicker in the middle of the skin
plaster than at the edge region. An adhesive layer which tapers to
the edge of the skin plaster avoids the skin plaster rolling up off
the skin and thus prolongs the possible wearing time. In the case
of thin adhesive layers, however, it is also possible to dispense
with a tapering at the edge region without the possible wearing
time being significantly impaired.
[0048] The skin plasters according to the invention are
water-vapor-permeable. The water-vapor permeability of the skin
plasters according to the invention is at least 50 g/m.sup.2,
preferably at least 80 g/m.sup.2, particularly preferably at least
100 g/m.sup.2, in a period of 24 hours. The water-vapor
permeability of the skin plasters according to the invention is
usually below 1000 g/m.sup.2, in the case of specific embodiments
below 400 g/m.sup.2, preferably below 250 g/m.sup.2, particularly
preferably below 150 g/m.sup.2, based on a period of 24 hours.
[0049] On account of the hydrophilic, water-swellable particles in
the adhesive layer, the skin plasters according to the invention
are able to absorb a certain amount of moisture.
[0050] The amount of moisture which can be absorbed is dependent,
inter alia, on the thickness of the adhesive layer, the material of
the hydrophilic, water-swellable particles and their content in the
adhesive layer.
[0051] In preferred embodiments, the skin plaster according to the
invention has an absorption capacity of at least 40 g/m.sup.2/6 h,
preferably of at least 50 g/m.sup.2/6 h, particularly preferably of
at least 60 g/m.sup.2/6 h and very particularly preferably of at
least 70 g/m.sup.2/6 h. The absorption capacity is up to 250
g/m.sup.2/6 h, preferably up to 300 g/m.sup.2/6 h, particularly
preferably up to 400 g/m.sup.2/6 h and very particularly preferably
up to 600 g/m.sup.2/6 h. The absorption capacity is determined by
immersing a skin plaster completely in physiological sodium
chloride solution (0.9 M NaCl in water) at a temperature of
37.degree. C. for a duration of 6 hours, and then determining the
absorbed amount of water.
[0052] The skin plaster according to the invention can have a
covering which absorbs moisture or wound exudate. The absorbent
covering is situated on the surface of the adhesive layer which
faces the back layer. The absorbent layer can consist of any
desired suitable material, for example gauze, alginates, collagens,
foams, superabsorbents or the like. Coverings of this kind and the
materials suitable for them are known to the person skilled in the
art.
[0053] The skin plasters according to the invention are suitable
for covering cut wounds or graze wounds, and also scars, other skin
lesions and the like.
[0054] In one particular embodiment, the skin plasters according to
the invention comprise an antiviral active ingredient or a mixture
of antiviral active ingredients in the adhesive layer.
[0055] The antiviral active ingredient, at least one of the
antiviral active ingredients or the antiviral active ingredients
is/are preferably selected from the group of active ingredients
which includes aciclovir, valaciclovir, penciclovir, famciclovir,
brivudine, adenine arabinoside and phosphonoformic acid, also known
under the proprietary name Foscarnet.
[0056] The antiviral active ingredient, at least one of the
antiviral active ingredients or the antiviral active ingredients
can also be selected from the group of active ingredients which
comprises silicic acid, n-docosanol and idoxuridine. Although these
active ingredients are not primarily considered to be antiviral,
they nevertheless have a good antiviral effectiveness.
[0057] The content of antiviral active ingredient or of antiviral
active ingredients in the adhesive layer is at least 0.1% by
weight, preferably at least 1.0% by weight, based on the mass of
the active-ingredient-containing adhesive layer. The
active-ingredient-containing adhesive layer can comprise up to 20%
by weight of active ingredient, but preferably comprises not more
than 10% by weight, in each case based on the mass of the
active-ingredient-containing adhesive layer. It is known to the
person skilled in the art that the amount of active ingredient to
be used depends on the active ingredient to be used or the active
ingredient mixture to be used.
[0058] The embodiments of the skin plasters according to the
invention which comprise at least one antiviral active ingredient
are suitable for covering skin lesions which are caused by an
infection with viruses, for example the so-called "herpes blisters"
in the case of an infection with Herpes simples labialis.
[0059] The skin plasters according to the invention have a
removable protective layer or protective film ("release liner")
which covers the adhesive layer on its surface facing the back
layer. The adhesive surface can be covered completely by a
single-part protective layer, or two or more protective layers can
partly cover the adhesive surface, it being preferred for the
entire adhesive surface to be covered. The protective layer(s) or
protective film(s) is/are to be removed prior to or while applying
the skin plaster to the skin.
[0060] Suitable material for the protective layer is, for example,
siliconized paper or plastic films, for example made of
polyethylene terephthalate, polyester, polyethylene, which are
optionally provided with a nonstick coating. Materials for a
protective layer for covering an adhesive layer of skin plasters
are known to the person skilled in the art.
[0061] It is not necessary for the protective layer to have the
same size and/or shape as the skin plaster. It is, for example,
possible to apply two or more skin plasters to a single protective
layer or a plurality of common protective layers.
[0062] In particular, a single-part protective layer can also be
designed as part of the primary packaging for the skin plaster
according to the invention.
[0063] The skin plasters according to the invention can be produced
using known methods for producing skin plasters.
[0064] The skin plasters according to the invention are
exceptionally suitable for a use as covering of cut wounds or graze
wounds, scars, skin lesions and the like, where they have a good
water-vapor permeability and at the same time a high adhesive
power. The skin plasters according to the invention are thus
characterized by a long wearing time and, with them, it is also
possible to create optimum conditions for moist wound healing
without resulting in an undesired accumulation of moisture
underneath the skin plaster.
[0065] The invention is illustrated by the following working
examples:
EXAMPLE 1
[0066] 289.56 g of Foral 85E (a glycol ester of dehydrogenated
colophony) are added, with stirring, to 288.01 g of
special-boiling-point spirit 80/110 and homogenized. 99.23 g of
Kraton D 1161 NU (a linear block copolymer based on styrene and
isoprene) are then added. The mixture is homogenized. Finally, 43.2
p of Na carboxymethylcellulose (CRT 60000 SPA 07) are added and the
mixture is stirred until completely homogeneous.
[0067] The mixture is spread in a thickness of 200 .mu.m on a
polyurethane film on support paper (type U 50, 55 g/m.sup.2 from
Smith & Nephew). The layered mass is dried in the drying
cabinet for 40 min at room temperature and then for 30 min at
60.degree. C. This results in a weight per unit area of 100
g/m.sup.2. It is covered with a release liner (brand: Silphan 100
.mu.m tsp AB1, 140 g/m.sup.2).
EXAMPLE 2
[0068] 72.4 g of Foral 85E and, in three portions, 24.8 g of
[0069] Kraton D1161 are added, with stirring, to 72.0 g of
special-boiling-point spirit 80/110. 10.8 g of sodium
carboxymethylcellulose are then added to the mass and homogenized
with stirring. The bubble-free mass is applied in a coating
thickness of 200 .mu.m to a siliconized PE film and brought from
room temperature to 60.degree. C. in the drying cabinet with
increasing temperature (1.degree./min).
[0070] The resulting laminate with a weight per unit area of 98
g/m.sup.2 is covered with a PU film of thickness 50 .mu.m. Round
plasters with an area of 1.77 cm.sup.2 are punched from the present
laminate.
* * * * *