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Patent 2692799 Summary

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(12) Patent Application: (11) CA 2692799
(54) English Title: PROCESS FOR PRODUCING POLYURETHANE FOAMS FOR WOUND MANAGEMENT
(54) French Title: PROCEDE DE FABRICATION DE MOUSSES DE POLYURETHANNE POUR LE TRAITEMENT DES BLESSURES
Status: Dead
Bibliographic Data
(51) International Patent Classification (IPC):
  • A61L 15/42 (2006.01)
  • C08L 75/00 (2006.01)
(72) Inventors :
  • MAGER, MICHAEL (Germany)
  • LUDEWIG, MICHAEL (Germany)
  • MATNER, MATHIAS (Germany)
  • DIETZE, MELITA (Germany)
  • FUGMANN, BURKHARD (Germany)
(73) Owners :
  • BAYER MATERIALSCIENCE AG (Germany)
  • BAYER MATERIALSCIENCE AG (Germany)
(71) Applicants :
  • BAYER MATERIALSCIENCE AG (Germany)
  • BAYER INNOVATION GMBH (Germany)
(74) Agent: FETHERSTONHAUGH & CO.
(74) Associate agent:
(45) Issued:
(86) PCT Filing Date: 2008-06-27
(87) Open to Public Inspection: 2009-01-15
Examination requested: 2013-06-25
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/EP2008/005259
(87) International Publication Number: WO2009/007018
(85) National Entry: 2010-01-07

(30) Application Priority Data:
Application No. Country/Territory Date
07013425.9 European Patent Office (EPO) 2007-07-10

Abstracts

English Abstract




The present invention relates to novel polyurethane-based wound
contact materials, obtained by foaming and curing of silane-terminated
polyurethanes.


French Abstract

La présente invention concerne de nouveaux pansements à base de polyuréthanne qui sont obtenus par expansion et durcissement de polyuréthannes à terminaison silane.

Claims

Note: Claims are shown in the official language in which they were submitted.




-13-

Claims


1. Use of foams obtainable from silane-terminated polyurethane prepolymers as
wound contact
materials.


2. Process for producing wound contact materials wherein a composition
comprising

a) silane-terminated polyurethane prepolymers (1) comprising more than one
alkoxysilane
group

obtainable by reacting

i) polyurethane prepolymers (A) having free isocyanate groups to an average
NCO
functionality of at least 1.5 with

ii) di- and/or trialkoxysilanes (B) having amino, hydroxyl and/or thiol groups
bonded to
the silicon atom via an alkylene radical,

or
iii) polyhydroxy compounds (C) having an average OH functionality of at least
1.5 with

iv) di- and/or trialkoxysilanes (D) having isocyanate and/or isothiocyanate
groups bonded
to the silicon atom via an alkylene radical,

b) (foam) additives (II)

c) optionally catalysts (III),

d) optionally blowing agents (IV), and also

e) optionally further, auxiliary and adjunct materials (V)

is foamed, applied to a substrate before, during or after foaming and finally
cured in the
presence of water.


3. Process according to Claim 2, characterized in that the silane-terminated
prepolymers (I) are
based on polyisocyanates or polyisocyanate mixtures having exclusively
aliphatically and/or
cycloaliphatically bound isocyanate groups and an average NCO functionality of
2 to 4.


4. Process according to Claim 2 or 3, characterized in that additives (II)
comprise nonionic
surfactants based on polyether siloxanes.



-14-


5. Process according to any one of the Claims 2 to 4, characterized in that
the compositions to be
foamed comprise, based on dry substance, 85 to 99.9 parts by weight of silane-
terminated
polyurethane prepolymer (I) and 0.1 to 15 parts by weight of the (foam)
additive (II) and also 0
to 50 parts by weight of auxiliary and adjunct materials (V).


6. Process according to any one of the Claims 2 to 5, characterized in that
water is added for
curing, in an amount such that the molar ratio of alkoxysilane groups in the
silane-terminated
prepolymer to added water is less than or equal to 1.


7. Wound contact materials obtainable by a process according to any one of the
Claims 2 to 6.

8. Use of compositions comprising

a) silane-terminated polyurethane prepolymers (I) comprising at least one
alkoxysilane
group

b) (foam) additives (II)

c) optionally catalysts (III),

d) optionally blowing agents (IV), and also

e) optionally further, auxiliary and adjunct materials (V)
for producing contact materials for wound management.

Description

Note: Descriptions are shown in the official language in which they were submitted.



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PROCESS FOR PRODUCING POLYURETHANE FOAMS FOR WOUND
MANAGEMENT

The present invention provides novel polyurethane-based wound contact
materials, obtained by
foaming and curing silane-terminated polyurethanes.

The use of wound contact materials made of foams for managing weeping wounds
is prior art.
Owing to their high absorbency and their good mechanical properties,
polyurethane foams
produced by reaction of mixtures of diisocyanates and polyols or NCO-
functional polyurethane
prepolymers with water in the presence of certain catalysts and also (foam)
additives are generally
used. Aromatic diisocyanates are generally employed, since they are best
foamable. Numerous
forms of these processes are known, for example described in US 3,978,266, US
3,975,567 and
EP-A 0 059 048. However, the aforementioned processes have the disadvantage
that they require
the use of reactive mixtures, comprising diisocyanates or appropriate NCO-
functional
prepolymers, whose handling is technically inconvenient and costly, since
appropriate protective
measures are necessary for exaniple. Direct application of these mixtures to
(human) skin is not
possible because of the high reactivity of the isocyanate groups present.

As well as through the use of compositions comprising free isocyanate groups,
polyurethane foams
can also be produced using silane-terminated polyurethane prepolymers which
are foamable
through use of blowing agents. Numerous embodiments are known for producing
sealing and
insulating foams, for example describe(i in EP-A 1 098 920. The use of the
compositions for
producing wound contact materials was hitherto not recognized. Nor have the
critical requirements
for use as wound contact materials, such as good water vapour permeability and
high liquid uptake
capacity, hitherto been described.

It is an object of the present invention to provide polyurethane wound contact
materials which
avoid the abovementioned disadvantages of using isocyanato-containing,
reactive mixtures.

It has now been found that silane-terminated polyurethane prepolymers (STPs),
surprisingly, are
likewise very useful as wound contact materials for medical applications after
foaming and curing
through crosslinking of the silane groups.

The present invention accordingly provides for the use of foatns obtainable
from silane-terminated
polyurethane prepolymers as wound contact materials.

The present invention further provides a process for producing wound contact
materials wherein a
composition comprising

a) silane-terminated polyurethane prepolymers (I)


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b) (foam) additives (11)

c) optionally catalysts (III),

d) optionally blowing agents (IV), and also

e) optionally further, auxiliary and adjunct materials (V)

is foamed, applied to a substrate before, during or after foaming and finally
cured in the presence
of water.

The present invention further provides the wound contact materials obtainable
by the process of
the invention.

The invention further provides for the use of compositions comprising

a) silane-terminated polyurethane prepolymers (i) comprising more than one
alkoxysilane
group

b) (foam) additives (II)

c) optionally catalysts (III),

d) optionally blowing agents (IV), and also

e) optionally further, auxiliary and adjunct materials (V)
for producing contact materials for wound management.

Polyurethane foam wound contact materials herein are porous materials,
preferably having at least
partly an open-cell content, which consist essentially of polyurethanes
crosslinked via siloxane
bonds Si-O-Si and protect wounds by closing out germs or ambient effects,
provide rapid and high
absorption of physiological saline or exudate and ensure optimal wound
conditions through
suitable perviousness to moisture.

Silane-terminated polyurethane prepo9ymers (1) for the purposes of the
invention include all
(pre)polymers having more than one urethane group and more than one
alkoxysilane group, which
are capable in the presence of water and if appropriate catalysts (I11) of
reacting via siloxane bonds
Si-O-Si to form crosslinked polyuretha(ies.

Such silane-terminated prepolymers are obtainable by reacting

i) polyurethane prepolymers (A) having free isocyanate groups to an average
NCO


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functionality of at least 1.5 with

ii) di- and/or trialkoxysilanes (B) having amino, hydroxyl and/or thiol groups
bonded to the
silicon atom via an alkylene radical,

or
iii) polyhydroxy compounds (C) having an average OH functionality of at least
1.5 with

iv) di- and/or trialkoxysilanes (D) having isocyanate and/or isothiocyanate
groups bonded to
the silicon atom via an alkylene raclical.

The polyurethane prepolymers (A), which contain free isocyanate groups, are
obtainable in a
conventional manner by the reaction of organic polyisocyanates with
polyhydroxy compounds
having a functionality of 1.5 to 6 by using the organic polyisocyanates in
excess (molar ratio
NCO/OH > 1).

Suitable polyisocyanates include the well-known aromatic, araliphatic,
aliphatic or cycloaliphatic
polyisocyanates having an average NCO functionality of > 2.

Examples of such suitable polyisocyariates are 1,4-butylene diisocyanate, 1,6-
hexamethylene
diisocyanate (HDI), isophorone diisocyanate (IPDI), 2,2,4 and/or 2,4,4-
trimethylhexamethylene
diisocyanate, the isomeric bis(4,4'-isocyanatocyclohexyl)methanes or their
mixtures of any desired
isomer content, 1,4-cyclohexylene diisocyanate, 1,4-phenylene diisocyanate,
2,4- and/or
2,6-toluylene diisocyanate, 1,5-naphthylene diisocyanate, 2,2'- and/or 2,4'-
and/or 4,4'-diphenyl-
methane diisocyanate, 1,3- and/or 1,4-bis(2-isocyanatoprop-2-yl)benzene
(TMXDI), 1,3-bis-
(isocyanatomethyl)benzene (XDI), and also alkyl 2,6-diisocyanatohexanoate
(lysine diisocyanates)
having Cl-C8-alkyl groups, and 4-isocyanatomethyl-1,8-octane diisocyanate
(nonane triisocyanate)
and triphenylmethane 4,4',4"-triisocyanate.

As well as the aforementioned polyisocyanates, it is also possible to use,
proportionally, modified
diisocyanates or triisocyanates of uretdione, isocyanurate, urethane,
alloplianate, biuret, imino-
oxadiazinedione and/or oxadiazinetriorne structure.

Preferably, the polyisocyanates or polyisocyanate mixtures of the
aforementioned kind have
exclusively aliphatically and/or cycloaliphatically attached isocyanate groups
and an average NCO
functionality in the range from 2 to 4, preferably in the range from 2 to 2.6
and more preferably in
the range from 2 to 2.4. It is particularly preferable to utilize 1,6-
hexamethylene diisocyanate,
isophorone diisocyanate, the isomeric bis(4,4'-isocyanatocyclohexyl)methanes,
and also mixtures
thereof.


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Useful polyhydroxy compounds for component (C) include all well-known
polyurethane coating
technology polyester polyols, polyacrylate polyols, polyurethane polyols,
polycarbonate polyols,
polyether polyols, polyester polyacrylate polyols, polyurethane polyacrylate
polyols, polyurethane
polyester polyols, polyurethane polyether polyols, polyurethane polycarbonate
polyols and
polyester polycarbonate polyols that have an average OH functionality of at
least 1.5. These can be
used individually or in any desired mixtures with each or one another.
Preference, however, is
given to using polyether polyols.

Polyester polyols for component (C) are the well-known polycondensates formed
from di- and also
optionally tri- and tetraols and di- and also optionally tri- and
tetracarboxylic acids or hydroxy
carboxylic acids or lactones. Instead of the free polycarboxylic acids it is
also possible to use the
corresponding polyearboxylic anhydrides or corresponding polycarboxylic esters
of lower alcohols
for preparing the polyesters.

Examples of suitable diols for producing polyester polyols are ethylene
glycol, butylene glycol,
diethylene glycol, triethylene glycol, polyalkylene glycols such as
polyethylene glycol, also
1,2-propanediol, 1,3-propanediol, butanediol(1,3), butanediol(1,4),
hexanediol(1,6) and isomers,
neopentyl glycol or neopentyl glycol hydroxypivalate, of which hexanediol(1,6)
and isomers,
neopentyl glycol and neopentyl gtycol hydroxypivalate are preferred.
Trimethylolpropane,
glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl
isocyanurate are
suitable, for example, as triols and tetraols.

Useful dicarboxylic acids include phthalic acid, isophthalic acid,
terephthalic acid, tetra-
hydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid,
adipic acid, azelaic
acid, sebacic acid, glutaric acid, tetrachlorophthalic acid, maleic acid,
fumaric acid, itaconic acid,
malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethyl glutaric acid
and/or
2,2-dimethylsuccinic acid. The corresponding anhydrides can also be used as a
source of acid.
Preferred acids are aliphatic or aromatic acids of the aforementioned kind.
Adipic acid, isophthalic
acid and optionally trimellitic acid are particularly preferred.

Hydroxy carboxylic acids useful as reaction participants in the preparation of
a polyester polyol
having terminal hydroxyl groups include for example hydroxycaproic acid,
hydroxybutyric acid,
hydroxydecanoic acid, hydroxystearic acid and the like. Suitable lactones
include caprolactone,
butyrolactone and homologues. Caprolactone is preferred.

Useful polyhydroxy compounds for component (C) further include polycarbonates,
preferably
polycarbonate diols, having number average molecular weights Mõ in the range
from 400 to
8000 g/mol, preferably in the range from 600 to 3000 g/mol. These are
obtainable in a
conventional manner by reaction of carbonic acid derivatives, such as diphenyl
carbonate,


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5-
dimethyl carbonate or phosgene, with polyols, preferably diols.

Examples of diols useful for preparing polycarbonates are ethylene glycol, 1,2-
propanediol, 1,3-
propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol,
neopentyl glycol,
1,4-bishydroxymethylcyclohexane, 2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-
pentanediol,
dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene
glycols, bisphenol A
and lactone-modified diois of the aforementioned kind.

The polycarbonate diol preferably contains 40% to 100% by weight of
hexanediol, preference
being given to 1,6-hexanediol and/or hexanediol derivatives based on the
underlying diols. Such
hexanediol derivatives are based on hexanediol and have ester or ether groups
as well as terminal
OH groups. Such derivatives are obtainabhe by reaction of hexanediol with
excess caprolactone or
by etherification of hexanediol with itself to form di- or trihexylene glycol.

Useful polyhydroxy compounds for component (C) further include polyether
polyols. Suitable are
for example the polytetramethylene glycol polyethers which are known per se in
polyurethane
chemistry and are obtainable by polymerization of tetrahydrofuran by means of
cationic ring
opening.

Preferred polyether polyols for component (C) include the well-known addition
products of
styrene oxide, ethylene oxide, propylene oxide, butylene oxides and/or
epichlorohydrin onto di- or
polyfunctional starter molecules, of which addition products of ethylene oxide
or propylene oxide,
and also mixtures of those mentioned, are particularly preferred. Very
particular preference is
given to addition products of ethylene oxide and propylene oxide in each of
which the weight
fraction of ethylene oxide is at least 5% to 80% by weight, preferably 10% to
65% by weight and
more preferably 10% to 30% by weight, this weight fraction being based on the
total of ethylene
oxide and propylene oxide units present in the addition product, plus the
starter molecules used.
The alkoxylation with etliylene oxide or propylene oxide can take place under
base catalysis or
through use of double metal cyanide (DPvIC) compounds.

Useful starter molecules for preparing the polyether polyols of component (C)
include all prior art
low molecular weight polyols, organic polyamines and/or water, for example
butyl diglycol,
glycerol, diethylene glycol, trimethylolpropane, propylene glycol, sorbitol,
ethylenediamine,
triethanolamine, 1,4-butanediol. Preferi-ed starter molecules are water,
ethylene glycol, propylene
glycol, 1,4-butanediol, diethylene glycel, butyl diglycol or any mixtures
thereof.

The number average molecular weight Mõ of the polyether polyols is preferably
in the range from
300 to 20 000 g/mol, more preferably in the range from 1000 to 12 000 g/inol
and most preferably
in the range from 2000 to 6000 g/mol.


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Reaction of organic di- or polyisocyanates 'with polyhydroxy compounds having
a functionality of
1.5 to 6 in an NCO/OH molar ratio < I gives polyhydroxy compounds having
urethane groups and
likewise useful as component (C).

Di- and/or trialkoxysilanes having amino, hydroxyl and/or thiol groups and
useful for
component (B) are well known to a person skilled in the art, examples being
amino-
propyltrimethoxysi lane, mercaptopropyltrimethoxysilane,
aminopropylmethyldimethoxysilane,
mercaptopropylmethyldimethoxysilane, ,aminopropyltriethoxysilane,
mercaptopropyltriethoxy-
silane, aminopropylmethyldiethoxysilane, mercaptopropylmethyldiethoxysilane,
aminomethyl-
trimethoxysilane, aminomethyltriethoxysilane, (aminomethyl)methyldimethoxysi
lane,
(aminomethyl)methyldiethoxysilane, N-butylaminopropyltrimethoxysilane, N-
ethylaminopropyl-
trimethoxysi lane, N-phenylaminopropyltrimethoxysilane, diethyl N-(3-
triethoxysilylpropyl)-
aspartate, diethyl N=(3-trimethoxysilylpropyl)aspartate and diethyl N-(3-
dimethoxymethylsilyl-
propyl)aspartate. The use of diethyl N-(3-trimethoxysilylpropyl)aspartate and
aminopropyltrimethoxysi lane is preferred.

Di- and/or trialkoxysilanes having isocyanate and/or isothiocyanate groups and
useful for
component (D) are likewise known in principle.

Examples are isocyanatomethyltrimethoxysi lane, isocyanatomethyltriethoxysi
lane,
(isocyanatomethyl)methyldimethoxysilane,
(isocyanatomethyl)methyldiethoxysilane, 3-isocyanato-
propyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-
isocyanatopropyltriethoxy-
silane and 3-isocyanatopropylmethyldiethoxysilane. Preference is here given to
the use of
3 -isocyanatopropyltrimethoxysi lane and 3-isocyanatopropyltriethoxysilane.

The additives (II) are nonionic, anionic, cationic or zwitterionic surfactants
or mixtures thereof,
which serve in the compositions of the invention to improve foam formation,
foam stability or the
properties of the resulting polyurethane foam. Preferred additives (II) are
nonionic surfactants,
more preferably nonionic surfactants based on polyether siloxanes.

The preferred additives (11) have not orily a stabilizing effect but also a
particularly advantageous
influence with regard to the hydrophilicization of the foams, which manifests
itself in moisture
uptake quantity and rate.

Useful catalysts (III) for inclusion in the compositions of the invention
include in principle all
materials known per se from silicon chemistry wliich catalyse the hydrolysis
and condensation of
alkoxysilanes and silanol groups, respectively. Examples are metal salts,
metal complexes,
organometallic compounds and also a.cids and bases. Preference is given to use
of organic and
inorganic acids or bases and particular preference to the use of organic or
inorganic acids such as


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for example hydrochloric acid or p-tolueriesulphonic acid. When catalysts
(III) are used in the
compositions, they are preferably dissolved in water which is also required
for the actual
crosslinking of the foams.

Blowing agents (IV) can most simply be air or nitrogen, but it is of course
also possible to use any
other blowing agents for foaming the composition of the invention which are
known per se from
polyurethane chemistry. Examples are n-butane, i-butane, propane and dimethyl
ether and also
mixtures thereof.

Useful auxiliary and adjunct materials (V) include for example fillers,
thickeners or thixotroping
agents, antioxidants, light stabilizers, plasticizers, pigments and/or flow
control agents.

Preferred auxiliary and adjunct materials are fillers, preferably inorganic
fillers, which can
contribute to improving the mechanical properties of the polyurethane foam of
the invention.
Useful examples include chalks and finelv divided silicas, in particular fumed
silicas.

Useful plasticizers include any natural or synthetic material sufficiently
compatible with the
polyurethane foam. Examples of suitable plasticizers are camphor, esters of
(aliphatic)
dicarboxylic acids, for example of adipic acid, polyesters, in particular
based on adipic, sebacic,
azelaic and phthalic acid acid condensed with 1,3-butanediol, 1,4-butanediol
or 1,6-hexanediol,
and also phosphoric esters, fatty acid esters and hydroxy carboxylic esters
(for example based on
citric acid, tartaric acid or lactic acid).

Curing by crosslinking the alkoxysilane groups to form siloxane bridges takes
place in the
presence of water, which can be directly added in liquid form, for example as
a solvent for the
catalyst, or can come from the air in the form of atmospheric humidity.

The compositions essential to the invention typically contain, based on dry
substance, 80 to
99.9 parts by weight of the silane-terminated polyurethane prepolymer (I) and
0.1 to 20 parts by
weight of the (foam) additive (11). Preferably, the compositions contain,
based on dry substance, 85
to 99.9 parts by weight of silane-terminated polyurethane prepolymer (1) and
0.1 to 15 parts by
weiglit of (foam) additive (ll), more preferably 95 to 99.9 parts by weight of
(1) and 0.1 to 5 parts
by weight of (11).

Auxiliary and adjunct materials (V) are typically added in amounts of 0 to 50
parts by weight,
preferably 10 to 40 parts by weight.

Water added for crosslinking beyond ambient moisture is typically added in an
amount such that
the molar ratio of alkoxy groups to added water is less than or equal to
1(excess water). The molar
ratio is preferably less than or equal to 0.75 and more preferably less than
or equal to 0.55.


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The blowing agent or blowing agent mixture (IV) is typically used in an amount
of 1% to 50% by
weight, preferably 5% to 40% by weight and more preferably 5% to 20% by
weight, the sum total
of the employed components (I), (11) and optionally (III), (IV), (V) being
100% by weight.

The mixing of components (I) and (II) can take place in any order, as can the
mixture with the
optional components (III) to (V).

Preferably, components (I) and (II) and also optionally (III) to (V) are each
provided separately;
that is, the reactive component (I) is provided in the absence of water and
the optional catalyst
(I1I). This gives a composition which is stable in storage at 23 C for at
least 6 months (stable in
storage is to be understood as meaning an increase in the viscosity of the
mixture of less than 50%,
preferably less than 25% and more preferably less than 15% based on the
starting level of the
composition).

Foaming in the process of the invention is accomplished by shaking of the
composition,
mechanical stirring at high speeds of rotation or by decompressing a blowing
gas. After or during
foaming, the composition undergoes curing to obtain the desired polyurethane
foam. Before
complete solidification or curing, i.e. as long as the composition is still
flowable, it can be applied
to a suitable substrate by common app'lication techniques such as pouring or
blade coating. In
addition, the composition can be applied directly to human or animal skin, in
which case foaming
and curing then generally take place simultaneously.

Mechanical foaming can be effected using any desired mechanical stirring,
mixing and dispersing
techniques. Air is generally introduced in the process, but nitrogen and other
gases can also be
used for this purpose.

The foam thus obtained is, in the course of foaming or immediately thereafter,
applied to a
substrate or introduced into a mould and cured.

Application to a substrate can be for e3s:ample by pouring or blade coating,
but other conventional
techniques are also possible. Multilayer application with optionally
intervening curing steps is also
possible in principle.

A satisfactory curing rate for the foanis is observed at a temperature as low
as 20 C. However,
liigher temperatures of preferably more than 30 C can also be employed for
faster curing and
fixing of the foams, for example with t'he aid of conventional heating and
drying apparatus, such as
(circulating air) drying cabinets, hot air or IR radiators.

The compositions may be applied, after foaming or while foaming, directly to
the skin or, in the
course of an industrial manufacture of wound contact materials, to release
papers or foils/films


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which facilitate simple detachment of the wound contact material before its
use for covering an
injured site.

Application and curing can each be carried out batchwise or continuously, but
an entirely
continuous process is preferable for the industrial manufacture of wound
contact materials.

When the composition is applied directly, by spraying for example, to human or
animal skin,
curing likewise takes place very rapidly at ambient conditions and as a result
of the body's
temperature, respectively. The assistance of an external source of heat is
similarly possible here,
although not preferable.

In one embodiment of the present invention, the sitane-terminated polyurethane
prepolymer (I) is
mixed with the additive (II) and optionally further, auxiliary and adjunct
materials (V). After
foaming of the mixture, for example due to mechanical incorporation of air or
of some other gas,
catalyst (I11) is added, the (foamed) mixture is applied to a suitable
substrate and finally cured in
the presence of atmospheric humidity. To speed the curing of the foamed
mixture, moreover, water
can be added, which is preferably done tcigether with the (dissolved) catalyst
(III).

In a further embodiment of the present invention, the silane-terminated
polyurethane
prepolymer (I) is mixed with the additive (II) and optionally further,
auxiliary and adjunct
materials (V) and transferred into a suitable pressure container, for example
a spray can.
Thereafter, the blowing agent (IV) is added; as the mixture is applied to a
suitable substrate, it
foams and is cured through atmospheric humidity.

In a further embodiment of the present invention, the silane-terminated
polyurethane
prepolymer (I) is mixed with the additive (II) and optionally further,
auxiliary and adjunct
materials (V) and transferred into a firs1: chamber of a suitable pressure
container, for example into
a spray can, the pressure container having at least 2 separate chambers.
Catalyst (III), which is
preferably mixed with a suitable amolunt of water, is introduced into a second
chamber of the
pressure container. The auxiliary and adjunct materials (V) can also be
admixed in the second
chamber, but this is less preferably. Thten, the blowing agent (IV) is added
to either or both of the
chambers and, finally, the two-component mixture is applied to a suitable
substrate, and at the
same time foaming and curing takes place.

Before curing, the foam densities of the polyurethane foams are typically in
the range from 50 to
800 g/litre, preferably in the range from 100 to 500 g/litre and more
preferably in the range from
100 to 250 g/litre (mass of all input materials [in g] based on the foam
volume of one litre).

After drying, the polyurethane foams have a microporous, at least partially
open-cell structure
comprising intercommunicating cells. The density of the cured foams is
typically below 0.4 g/cm3,


CA 02692799 2010-01-07
WO 2009/007018 PCT/EP2008/005259
- 10-

preferably less than 0.35 g/cm; and more preferably in the range from 0.01 to
0.2 g/cm-.

The DIN EN 13726-1 Part 3.2 physiological saline absorbency is typically 100
and 1500% and
preferably in the range from 300 to 800 /0 for the polyurethane foams (mass of
liquid taken up,
based on mass of dry foam). The DIN EN 13726-2 Part 3.2 vapour transmission
rate is typically in
the range from 500 to 8000 g/24 h * m2, preferably in the range from 1000 to
6000 g/24 h * m2 and
more preferably in the range from 2000 to 5000 g/24 h * m2.

The polyurethane foams exhibit good mechanical strength and high elasticity.
Typically, maximum
stress is greater than 0.1 N/mm2 and maximum extension is greater than 100%.
Preferably,
extension is greater than 200% (determined according to DIN 53504).

After curing, the thickness of the polyurethane foams is typically in the
range from 0.1 mm to
50 mm, preferably in the range from 0.5 mm to 20 mm, more preferably in the
range from I to
10 mm and most preferably in the range from 1 to 5 mm.

The polyurethane foams can moreover be adhered, laminated or coated to or with
further materials,
for example materials based on hydrogels, (semi-) permeable films/foils,
coatings, hydrocolloids or
other foams.

It is likewise possible to add, incorporate or coat with antimicrobially or
biologically active
components which for example have a positive effect with regard to wound
healing and the
avoidance of germ loads.


CA 02692799 2010-01-07
WO 2009/007018 PCT/EP2008/005259
-11-
Examples=

Unless indicated otherwise, all percentages are by weight.

NCO contents were unless expressly mentioned otherwise determined
volumetrically in
accordance with DIN-EN ISO 11909.

Substances and abbreviations used:
PO propylene oxide
EO ethylene oxide
DBTL dibutyltin dilaurate

Tegostab` B 1048 polyethersiloxane (from Degussa, Dusseldorf, Germany)

Aerosil R 9200 finely divided, fumed silica (from Degussa, D'usseldorf,
Germany)
Mesamoil plasticizer based on an alkylsulphonic ester (from Lanxess,
Leverkusen,
Germany)

Preparation of silane-terminated prepolymer 1(STP 1):

A mixture of 2003.6 g of a difunctional, ethoxylated polyether (OH number 28,
molecular weight
4000 g/mol, PO/EO ratio = 6.5), 214.3 g of 3-isocyanatotrimethoxysilane and
133 l of DBTL was
heated to 60 C with stirring until the NCO content was 0.

Example 1: Production of a foam by base catalysis

1 17.5 g of STP I and 3.8 g of Tegostab B 1048 were mixed in a plastic beaker
using a hand
stirrer and foamed to a volume of about 300 ml over 10 min. Thereafter, 2.5 g
of aqueous
potassium hydroxide solution (1.25 mol/L) were added, whereupon curing took
place within 20 s.
A white foam was obtained.

Example 2: Production of foams by acid catalysis

a) 1 17.5 g of STP I and 3.8 g of Tegostab'o B 1048 were mixed in a plastic
beaker using a
hand stirrer and foamed to a volume of about 300 ml over 10 min. Thereafter,
2.5 g of
a 5% aqueous solution of p-toluenesulphonic acid were added, whereupon curing
took
place within 20 s. A white foam was obtained.

b) Experiment a) was repeated with 2 g of a 20% aqueous solution of p-
toluenesulphonic


CA 02692799 2010-01-07
WO 2009/007018 PCT/EP2008/005259
-12-
acid. Curing to form a white foam took place after just 50 s.

Example 3: Foam with filler and plasticizer

A dissolver was used to initially disperse 50 g of Aerosil R 9200 in 1 17.5 g
of STP 1(almost
transparent dispersion). Thereafter, 25 g of Mesamoll and 3.8 g of Tegostab
B 1048 were added,
and finally the mixture was foamed in a plastic beaker with a hand stirrer to
a volume of about
300 ml over 10 min. After addition of 2.5 g of a 5% aqueous solution of p-
toluenesulphonic acid,
curing to form a white foam was achieved within 20 s.

Representative Drawing

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Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date Unavailable
(86) PCT Filing Date 2008-06-27
(87) PCT Publication Date 2009-01-15
(85) National Entry 2010-01-07
Examination Requested 2013-06-25
Dead Application 2016-05-25

Abandonment History

Abandonment Date Reason Reinstatement Date
2015-05-25 R30(2) - Failure to Respond
2015-06-29 FAILURE TO PAY APPLICATION MAINTENANCE FEE

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $400.00 2010-01-07
Maintenance Fee - Application - New Act 2 2010-06-28 $100.00 2010-06-04
Registration of a document - section 124 $100.00 2011-05-19
Maintenance Fee - Application - New Act 3 2011-06-27 $100.00 2011-06-08
Maintenance Fee - Application - New Act 4 2012-06-27 $100.00 2012-06-12
Maintenance Fee - Application - New Act 5 2013-06-27 $200.00 2013-06-10
Request for Examination $800.00 2013-06-25
Maintenance Fee - Application - New Act 6 2014-06-27 $200.00 2014-06-10
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
BAYER MATERIALSCIENCE AG
BAYER MATERIALSCIENCE AG
Past Owners on Record
BAYER INNOVATION GMBH
DIETZE, MELITA
DIETZLE, MELITA
FUGMANN, BURKHARD
LUDEWIG, MICHAEL
MAGER, MICHAEL
MATNER, MATHIAS
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Description 2010-01-07 12 582
Claims 2010-01-07 2 54
Abstract 2010-01-07 1 5
Cover Page 2010-03-22 1 28
Assignment 2011-05-19 3 157
Assignment 2010-01-07 5 166
PCT 2010-01-07 4 145
Correspondence 2010-03-29 2 137
Correspondence 2010-10-20 1 50
Correspondence 2011-04-28 1 48
Prosecution-Amendment 2013-06-25 2 82
Prosecution-Amendment 2014-11-25 4 224
Correspondence 2015-01-15 2 58