Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0828—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing sulfonate groups or groups forming them
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
  • A61L15/26—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/42—Use of materials characterised by their function or physical properties
  • A61L15/425—Porous materials, e.g. foams or sponges
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2101/00—Manufacture of cellular products

Definitions

• the invention relates to a process for the production of polyurethane foams, by foaming and drying of mixtures of special polyurethane dispersions with n ⁇ tzer ⁇ .
• hydrophilic polyurethane foams are generally used for this purpose. These are obtained by reacting mixtures of diisocyanates and polyols or NCO-functional polyurethane prepolymers with water in the presence of certain catalysts and (foam) additives. As a rule, aromatic diisocyanates are used here, since they are best foamed. Numerous embodiments of these methods are known, for example described in US 3,978,266, US 3,975,567 and EP-A 0 059 048. However, the aforementioned methods have the disadvantage that reactive mixtures must be used, containing diisocyanates or corresponding prepolymers whose handling is technically complicated , because eg appropriate protective measures are required.
• foams from polyurethane dispersions by adding air in the presence of suitable (foam) additives by vigorous stirring. After drying and curing, so-called mechanical polyurethane foams are obtained.
• foams are described in connection with wound dressings in EP-A 0 235 949 and EP-A 0 246 723, either adding a self-adherent polymer to the foam or applying the foam to a film of a self-adherent polymer. The use of the foams as such, i. without self-adherent polymers is not described.
• EP-A 0 235 949 and EP-A 0 246 723 compulsorily describe the use of polyaziridines as crosslinkers which, according to the current state of knowledge, should only be used to a limited extent owing to their toxicity.
• US Pat. No. 4,655,210 describes the use of the aforementioned mechanical foams for wound dressings, which have a special construction of carrier, foam and skin contact layer.
• Dispersions are anionically hydrophilicized by incorporation of certain carboxylic acids such as dimethylolcarboxylic acids and neutralization of the carboxylic acids with tertiary amines, for example triethylamine.
• carboxylic acids such as dimethylolcarboxylic acids
• tertiary amines for example triethylamine.
• the ammonium carboxylates thus formed are decomposable, especially at higher temperatures, thereby releasing the amines again become. This is a great disadvantage in the processing of such products and especially in skin contact.
• the dimethy lolcarbon yarnren were also used dissolved, for example, in dimethylformamide or N-methylpyrrolidone, whereby the finished products have a high total content of health-critical volatile organic compounds (VOC), in the case of used Witcobond TM 290 H 10.8 g / liter (without water).
• VOC health-critical volatile organic compounds
• EP-A 0 760 743 moreover describes such mechanical foams based on latex dispersions, which however do not consist of polyurethanes and have inferior mechanical properties.
• Object of the present invention was therefore the provision of new wound dressings based on polyurethanes, which are accessible in the simplest possible way and without the use of harmful building components or additives. Another prerequisite is that these wound dressings have good mechanical properties, a high absorption capacity of physiological saline solution and a high water vapor permeability. Furthermore, the foams should have a satisfactory water resistance.
• foaming compositions which comprise special aqueous polyurethane dispersions and crosslinkers, and then drying them with at least partial crosslinking.
• the present invention therefore provides a process for the production of foamed articles, preferably wound dressings, in which compositions comprising anionic hydrophilized aqueous polyurethane dispersions (I) by means of sulfonate groups are foamed together with crosslinkers (II) and dried with at least partial chemical crosslinking.
• crosslinking means the formation of covalent bonds between reactive groups of the crosslinker and the polyurethanes contained in the polyurethane dispersions.
• Wound coatings of polyurethane foams in the context of the invention are porous materials, preferably with at least partially present open-celledness, which essentially consists of
• These dispersions for anionic hydrophilization preferably contain only sulfonate groups.
• the specific polyurethane dispersions (I) preferably have a low degree of hydrophilic anionic groups, preferably from 0.1 to 15 milliequivalents per 100 g of polyurethane (solid resin).
• the number average particle size of the specific polyurethane dispersions is preferably less than 750 nm, more preferably less than 500 nm, determined by means of laser correlation spectroscopy.
• the polyurethane dispersions (I) preferably have solids contents of from 30 to 70% by weight, particularly preferably from 50 to 70% by weight, very particularly preferably from 55 to 65% by weight and in particular from 60 to 65% by weight on the polyurethane contained therein.
• polyurethane dispersions preferably have less than 0.5% by weight, more preferably less than 0.2% by weight, based on the total dispersions, of unbound organic amines.
• Such preferably used polyurethane dispersions (I) are obtainable in which
• polymeric polyols having number average molecular weights of 400 to
• Step B) are dispersed in water.
• the prepolymer can be completely or partially converted into the anionic form before, during or after the dispersion by admixing a base.
• hydrophilizing agents which have at least one NCO-reactive group, such as amino, hydroxy or thiol groups, and furthermore -COO " or -SO 3 " or -PO 3 2 ' as anionic or their fully or partially protonated acid forms as potentially anionic groups.
• Suitable polyisocyanates of component A1) are the aliphatic or cycloaliphatic polyisocyanates of an NCO functionality greater than or equal to 2 known to the person skilled in the art.
• polystyrene resin examples include 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, and the isomeric bisisocyanate.
• HDI 1,6-hexamethylene diisocyanate
• IPDI isophorone diisocyanate
• 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate examples include 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, and the isomeric bisisocyanate.
• polyisocyanates which have a functionality of> 2, with uretdione, isocyanurate, urethane, allophanate, biuret, iminooxadiazinedione or oxadiazinetrione structures and mixtures thereof.
• Hexamethylene diisocyanate, isophorone diisocyanate or the isomeric bis (4,4'-isocyanatocyclohexyl) methanes and mixtures of the abovementioned diisocyanates are particularly preferably used in Al).
• polymeric polyols having a number average molecular weight M n of 400 to 8000 g / mol, preferably from 400 to 6000 g / mol and particularly preferably from 600 to 3000 g / mol. These preferably have an OH functionality of from 1.5 to 6, particularly preferably from 1.8 to 3, very particularly preferably from 1.9 to 2.1.
• Such polymeric polyols are the polyester polyols known per se in polyurethane coating technology, 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. These can be used in A2) individually or in any mixtures with each other.
• polyester polyols are the known polycondensates of di- and optionally tri- and tetraols and di- and optionally tri- and tetracarboxylic acids or hydroxycarboxylic acids or lactones.
• free polycarboxylic acids it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols for the preparation of the polyesters.
• diols examples include ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols such as polyethylene glycol, furthermore 1,2-propanediol, 1,3-propanediol, butanediol (1,3), butanediol (1,4), hexanediol ( l, 6) and isomers, neopentyl glycol or
• Hydroxypivalic acid neopentyl glycol esters, with hexanediol (1,6) and isomers, butanediol (1,4), neopentyl glycol and neopentyl glycol hydroxypivalate being preferred.
• polyols such as trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate.
• phthalic acid isophthalic acid, terephthalic acid, tetrahydrophthalic 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-methyl succinic acid, 3,3-diethylglutaric acid and / or 2 , 2-dimethyl- ethylsuccinic acid are used.
• the acid source used may also be the corresponding anhydrides.
• monocarboxylic acids such as benzoic acid and hexanecarboxylic acid may additionally be used.
• Preferred acids are aliphatic or aromatic acids of the abovementioned type.
• adipic acid isophthalic acid and phthalic acid.
• Hydroxycarboxylic acids which may be co-used as reactants in the preparation of a hydroxyl-terminated polyester polyol include hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid, hydroxystearic acid and the like.
• Suitable lactones are caprolactone, butyrolactone and homologs. Preference is given to caprolactone.
• hydroxyl-containing polycarbonates preferably polycarbonatediols, having number-average molecular weights M n of from 400 to 8000 g / mol, preferably from 600 to 3000 g / mol.
• carbonic acid derivatives such as diphenyl carbonate, dimethyl carbonate or phosgene
• diols examples include ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bishydroxymethylcyclohexane, 2-Methyl-l, 3-propanediol, 2,2,4-Trimethylpentandiol-l, 3, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A and lactone-modified diols of the aforementioned type in question.
• the diol component contains 40 to 100 wt .-% of hexanediol, preferably 1,6-hexanediol and / or hexanediol derivatives.
• hexanediol derivatives are based on hexanediol and have terminal OH groups in addition to ester or Ethergrupp ⁇ n.
• Such derivatives are obtainable by reaction of hexanediol with excess caprolactone or by etherification of hexanediol with itself to give di- or triethylene glycol.
• Hydroxyl-containing polycarbonates are preferably built linear.
• polyether polyols can be used. Suitable examples are the polytetra methylene glycol polyethers known per se in polyurethane chemistry, such as are obtainable by polymerization of tetrahydrofuran by means of cationic ring opening.
• polyether polyols are the per se known addition products of styrene oxide, ethylene oxide, propylene oxide, butylene oxide and / or epichlorohydrin to di- or polyfunctional starter molecules.
• Polyether polyols, based on the at least proportional addition of ethylene oxide to di- or polyfunctional starter molecules, can also be used as component A4) (nonionic hydrophilicizing agents).
• starter molecules it is possible to use all known compounds according to the prior art, such as, for example, water, butyldiglycol, glycerol, diethylene glycol, trimethylolpropane, propylene glycol, sorbitol, ethylenediamine, triethanolamine, 1,4-butanediol.
• polyols of the stated molecular weight range having up to 20 carbon atoms such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butylene glycol, cyclohexanediol, 1,4 cyclohexanedimethanol,
• ester diols of the stated molecular weight range, such as ⁇ -hydroxybutyl- ⁇ -hydroxy-caproic acid ester, ⁇ -hydroxyhexyl- ⁇ -hydroxybutyric acid ester, adipic acid ( ⁇ -hydroxyethyl) ester or terephthalic acid bis ( ⁇ -hydroxyethyl) ester.
• monofunctional isocyanate-reactive hydroxyl group-containing compounds can also be used in A3).
• monofunctional compounds are ethanol, n-butanol, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether,
• Suitable anionic hydrophilic compounds of component A4) are salts of
• Suitable nonionically hydrophilicizing compounds of component A4) are, for example, polyoxyalkylene ethers which contain at least one hydroxyl, amino or thiol group.
• Examples are the monohydroxy-functional, on average 5 to 70, preferably 7 to 55 ethylene oxide units per molecule having Polyalkylenoxidpolyetheralkohole as they are accessible in a conventional manner by alkoxylation of suitable starter molecules (eg in Ulimann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 19 , Verlag Chemie, Weinheim pp. 31-38). These are either pure polyethylene oxide ethers or mixed polyalkylene oxide ethers, wherein they contain at least 30 mol%, preferably at least 40 mol%, of ethylene oxide units based on all the alkylene oxide units present.
• Particularly preferred nonionic compounds are monofunctional mixed polyalkylene oxide polyethers which have 40 to 100 mol% of ethylene oxide and 0 to 60 mol% of propylene oxide units.
• Suitable starter molecules for such nonionic hydrophilicizing agents are saturated monoalcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-
• Butanol the isomeric pentanols, hexanols, octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, the isomeric methylcyclohexanols or hydroxymethylcyclohexane, 3-ethyl-3- hydroxymethyloxetane or tetrahydrofurfuryl alcohol, diethylene glycol monoalkyl ethers, such as, for example, diethylene glycol monobutyl ether, unsaturated alcohols, such as allyl alcohol, 1,1-dimethylallyl alcohol or
• Oleic alcohol aromatic alcohols such as phenol, the isomeric cresols or methoxyphenols, araliphatic alcohols such as benzyl alcohol, anisalcohol or cinnamyl alcohol, secondary monoamines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis (2-ethylhexyl) amine, N-methyl and N-ethylcyclohexylamine or dicyclohexylamine and heterocyclic secondary amines such as morpholine, pyrrolidine, piperidine or 1H-pyrazole.
• Preferred starter molecules are saturated monoalcohols of the abovementioned type. Particular preference is given to using diethylene glycol monobutyl ether or n-butanol as starter molecules.
• Alkylene oxides which are suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, which can be used in any desired order or even as a mixture in the alkoxylation reaction.
• organic di- or polyamines such as, for example, 1,2-ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophorone diamine, isomer mixture of 2 , 2,4- and 2,4,4-Trirnethylhexamethylenediamm, 2-methyl- pentamethylenediamine, diethylenetriamine, 4,4-diaminodicyclohexylmethane and / or dimethyl ethylenediamine.
• 1,2-ethylenediamine 1,2- and 1,3-diaminopropane
• 1,4-diaminobutane 1,6-diaminohexane
• isophorone diamine isomer mixture of 2 , 2,4- and 2,4,4-Trirnethylhexamethylenediamm
• 2-methyl- pentamethylenediamine diethylenetriamine
• component Bl compounds which, in addition to a primary amino group, also have secondary amino groups or, in addition to an amino group (primary or secondary), also OH groups, can be used.
• primary / secondary amines such as diethanolamine, 3-amino-1-methylaminopropane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino-1-methylaminobutane, alkanolamines, such as N-aminoethylethanolamine, ethanolamine , 3-aminopropanol, neopentanolamine.
• component Bl it is also possible to use monofunctional isocyanate-reactive amine compounds, for example methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isononyloxypropylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl (methyl ) - aminopropylamine, Mo ⁇ holin, piperidine, or suitable substituted derivatives thereof, amide amines from diprimary amines and monocarboxylic acids, monoketim of diprimary amines, primary / tertiary amines, such as N, N-dimethylaminopropylamine.
• monofunctional isocyanate-reactive amine compounds for example methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, steary
• Suitable anionically hydrophilicizing compounds of component B2) are alkali metal salts of mono- and diaminosulfonic acids.
• anionic hydrophilizing agents are salts of 2- (2-aminoethylamino) ethanesulfonic acid, ethylenediamine propyl- or -butylsulfonic acid, 1,2- or 1,3-propylenediamine- ⁇ -ethylsulfonic acid or taurine.
• the salt of cyclohexylaminopropanesulfonic acid (CAPS) from WO-A 01/88006 can be used as an anionic hydrophilicizing agent.
• Particularly preferred anionic hydrophilicizing agents B2) are those which contain sulfonate groups as ionic groups and two amino groups, such as the salts of 2- (2-aminoethylamino) ethylsulfonic acid and 1,3-propylenediamine / 3-ethylsulfonic acid.
• hydrophilization it is also possible to use mixtures of anionic and nonionic hydrophilicizing agents.
• the components A1) to A4) and B1) to B2) are used in the following amounts, the individual amounts always adding up to 100% by weight:
• the components A1) to A4) and B1) to B2) are used in the following amounts, the individual amounts always adding up to 100% by weight:
• the components A1) to A4) and B1) to B2) are used in the following amounts, the individual amounts always adding up to 100% by weight:
• the preparation of the special polyurethane dispersions can be carried out in one or more stages in homogeneous or in multistage reaction, in some cases in disperse phase. After complete or partial polyaddition from Al) to A4), a dispersing, emulsifying or dissolving step takes place. This is followed, if appropriate, by a further polyaddition or modification in disperse phase. In this case, all known from the prior art methods such.
• prepolymer mixing method, acetone method or Schmelzdispergier vide can be used. Preference is given to proceeding by the acetone process.
• Suitable solvents are the customary aliphatic, ketofunctional solvents such as acetone, 2-butanone, which may be added not only at the beginning of the preparation, but optionally also in parts later. Preference is given to acetone and 2-butanone, particular preference to acetone.
• the molar ratio of isocyanate groups to isocyanate-reactive groups is 1.05 to 3.5, preferably 1.1 to 3.0, particularly preferably 1.1 to 2.5.
• step B NH 2 - and / or NH-functional components are reacted with the remaining isocyanate groups of the prepolymer.
• chain extension / termination is performed prior to dispersion in water.
• Suitable components for chain extension are organic di- or polyamines B1), such as, for example, ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-
• compounds B1) which, in addition to a primary amino group, also have secondary amino groups or, in addition to an amino group (primary or secondary), also OH groups.
• primary / secondary amines such as diethanolamine, 3-amino-1-methylaminopropane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino-1-methylaminobutane, alkanolamines such as N-aminoethylethanolamine, ethanolamine , 3-aminopropanol, neopentanolamine are used for chain extension or termination.
• amines Bl are usually used with an isocyanate-reactive group, such as methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isononyloxypropylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl (methyl) aminopropylamine, Morpholine, piperidine, or suitable substituted derivatives thereof, amide amines of diprimary amines and monocarboxylic acids, monocrimets of diprimary amines, primary / tertiary amines, such as
• the chain extension of the prepolymers is preferably carried out before the dispersion.
• the degree of chain extension ie the equivalent ratio of NCO-reactive groups of the compounds used for chain extension and chain termination to free NCO groups of the prepolymer, is between 40 and 150%, preferably between 50 and 120%, particularly preferably between 60 and 120%.
• the aminic components B1) and B2) can, if appropriate, be used in water-diluent or solvent-thinned form in the process according to the invention individually or in mixtures, it being possible in principle for any order of addition to be possible.
• the diluent content in the chain-extending component used in B) is preferably 70 to 95% by weight.
• the dispersion preferably takes place after the chain extension.
• the dissolved and chain-extended polyurethane polymer is optionally added under strong shearing, such as strong stirring, either in the dispersing water or it is conversely, the dispersing water is stirred into the chain-extended polyurethane polymer solutions.
• the water is added to the dissolved chain-extended polyurethane polymer.
• the solvent still present in the dispersions after the dispersion step is then usually removed by distillation. Removal during the dispersion is also possible.
• the residual content of organic solvents in the dispersions essential to the invention is typically less than 1% by weight, preferably less than 0.5% by weight, based on the total dispersion.
• the pH of the dispersions essential to the invention is typically less than
• 8.0 preferably less than 7.5 and is more preferably between 5.5 and 7.5.
• crosslinkers (II) it is possible in principle to use all organic, at least difunctional compounds which form covalent bonds with the polyurethane used of the polyurethane dispersion (I) under the stated drying conditions and thus to the desired improvement of the mechanical properties and / or the
• crosslinkers are unblocked, optionally hydrophilicized polyisocyanates, amide and amine-formaldehyde resins, phenolic resins, aldehyde and ketone resins, e.g. Phenol-formaldehyde resins, resoles, furan resins, urea resins, carbamic acid ester resins, triazine resins, melamine resins, benzoguanamine resins, cyanamide resins and aniline resins.
• crosslinkers are unblocked, optionally hydrophilicized polyisocyanates, amide and amine-formaldehyde resins, phenolic resins, aldehyde and ketone resins, e.g. Phenol-formaldehyde resins, resoles, furan resins, urea resins, carbamic acid ester resins, triazine resins, melamine resins, benzoguanamine resins, cyanamide resins
• unblocked polyisocyanates or melamine resins as crosslinkers, but particularly preferably unblocked polyisocyanates, very particularly preferably hydrophilicized polyisocyanates which can be incorporated particularly easily into the polyurethane dispersion (I) by all common mixing and dispersing techniques.
• compositions to be foamed may also contain auxiliaries and additives (IH).
• auxiliaries and additives are foam auxiliaries, such as foaming agents and stabilizers, thickeners or thixotropic agents, antioxidants, light stabilizers,
• Emulsifiers plasticizers, pigments, fillers and leveling agents.
• auxiliary agents and additives HI
• foam auxiliaries such as foaming agents and stabilizers.
• Commercially available compounds such as fatty acid amides, hydrosulfonates, sulfates or fatty acid salts are suitable, the lipophilic radical preferably containing from 12 to 24 carbon atoms, and alkyl polyglycosides which are known per se to the person skilled in the art by reaction of relatively long-chain monoalcohols (4 to 22 C). Atoms in the alkyl group) with mono-, di- or polysaccharides are available (see, eg, Kirk-Othmer, Encyclopedia of Chemical Technology, John Wiley & Sons, Vol. 24, p. 29).
• foam auxiliaries are EO / PO block copolymers which, according to the person skilled in the art, are known per se by the addition of ethylene oxide and propylene oxide
• OH or NH functional starter molecules are available (see, e.g., Kirk-Othmer, Encyclopedia of Chemical Technology, John Wiley & Sons, Vol. 24, p.
• further additives may be present in the component (IJJ).
• Such further additives may in principle be all anionic, nonionic and cationic surfactants known per se.
• thickeners may be used as thickeners, such as dextrin, starch or cellulose derivatives, e.g. Cellulose ethers or hydroxyethylcellulose, polysaccharide derivatives such as gum arabic, organic fully synthetic thickeners based on polyacrylic acids, polyvinylpyrrolidones, poly (meth) acrylic compounds or polyurethanes (associative thickeners) and also inorganic thickeners such as concreteites or silicic acids.
• cellulose derivatives e.g. Cellulose ethers or hydroxyethylcellulose
• polysaccharide derivatives such as gum arabic
• organic fully synthetic thickeners based on polyacrylic acids polyvinylpyrrolidones
• poly (meth) acrylic compounds or polyurethanes associative thickeners
• inorganic thickeners such as concreteites or silicic acids.
• compositions essential to the invention contain, based on dry matter, typically 90 to 99.9 parts by weight of the polyurethane dispersion (I), 0.1 to 10 parts by weight of the crosslinker (H) and 0 to 10 parts by weight of foam auxiliaries (IJJ).
• the compositions essential to the invention based on the dry substance, preferably contain from 87.5 to 98.9 parts by weight of dispersion (I), from 0.1 to 5 parts by weight of crosslinking agent (H) and from 1 to 7.5 parts by weight of foam aid (HI), more preferably 90.5 to 97 parts by weight of the dispersion (I), 0.5 to 2 parts by weight of the crosslinker (U) and 2.5 to 7.5 parts by weight of foam aid (based on the dry substance).
• the foaming in the process of the invention is done by mechanical stirring of the composition at high speeds, by shaking or by relaxation of a propellant gas.
• the mechanical foaming can be carried out with any mechanical stirring, mixing and dispersing techniques. As a rule, this air is entered, but also nitrogen and other gases can be used for this purpose.
• the foam thus obtained is applied to a substrate during foaming or immediately thereafter or placed in a mold and dried.
• the order can be made, for example, by casting or knife coating, but other techniques known per se are possible.
• a multi-layer application with intermediate drying steps is basically also possible.
• the application and the drying can each be carried out batchwise or continuously, but preference is given to a completely continuous process.
• Suitable substrates are papers (e.g., release papers) or films which allow easy release of the wound dressing prior to its use to cover an injured site.
• the drying is usually carried out using known heating and drying equipment, such as (convection) drying cabinets, hot air or IR lamps. typically at elevated temperatures of from 30 to 200 ° C., preferably from 100 to 170 ° C., particularly preferably from 110 to 160 ° C. Preference is given to drying at least two stages starting at temperatures of from 110 to 130 ° C. and subsequent further drying ( Crosslinking) at elevated temperatures of 130 to 160 0 C.
• heating and drying equipment such as (convection) drying cabinets, hot air or IR lamps.
• heated and drying equipment typically at elevated temperatures of from 30 to 200 ° C., preferably from 100 to 170 ° C., particularly preferably from 110 to 160 ° C.
• Preference is given to drying at least two stages starting at temperatures of from 110 to 130 ° C. and subsequent further drying ( Crosslinking) at elevated temperatures of 130 to 160 0 C.
• a further subject matter is the wound dressings obtainable by the process according to the invention.
• the wound dressings typically have foam densities of 50 to before they are dried
• 800 g / liter preferably 100 to 500 g / liter, particularly preferably 100 to 250 g / liter (mass of all starting materials [in g] based on the foam volume of one liter).
• the wound dressings After being dried, the wound dressings have a microporous, open-pore structure with cells which communicate with one another.
• the density of the dried foams is typically below 0.4 g / cm 3 , preferably less than 0.35 g / cm 3 , more preferably 0.01 to 0.3 g / cm 3 and most preferably at 0.1 to 0.3 g / cm 3 .
• the absorption capacity with respect to physiological saline solution in the case of polyurethane foams is typically 100 to 1500%, preferably 300 to 1500%, particularly preferably 300 to 800% (mass of the liquid absorbed, based on the mass of the dry foam, determination according to DIN EN 13726-1, Part 3.2).
• the permeability to water vapor is typically 2000 to 8000 g / 24 h * m 2 , preferably 2000 to 5000 g / 24 h * m 2 , particularly preferably 2000 to 4000 g / 24 h * m 2 (determined according to DIN EN 13726-2, Part 3.2).
• the polyurethane foams have good mechanical strength and high elasticity.
• the values for the maximum stress are greater than 0.2 N / mm 2 and the maximum elongation is greater than 250%.
• the maximum strain is greater than
• the wound dressings after drying typically have a thickness of 0.1 mm to 50 mm, preferably 0.5 mm to 20 mm, more preferably 1 to 10 mm, most preferably 1 to 5 mm.
• wound dressings can be bonded, laminated or coated with other materials, for example based on hydrogels, (semi-) permeable films, coatings, hydrocolloids or other foams.
• a step for sterilization can be carried out in the process according to the invention.
• sterilization the processes known to those skilled in the art are used, in which sterilization by thermal treatment, chemical substances such as ethylene oxide or irradiation, for example by gamma irradiation.
• Preferred active ingredients of the aforementioned type are those from the group of antiseptics, growth factors, protease inhibitors and non-steroidal anti-inflammatory drugs / opiates.
• the active ingredient comprises an antiseptic biguanide and / or its salt, preferably the hydrochloride.
• a biguanides are compounds derived from the biguanide (C 2 H 7 N 5 ), in particular its polymers.
• Antiseptic biguanides are those compounds which have an antimicrobial effect, ie act as bacteriostats or preferably as bactericides.
• the compounds preferably have a broad activity against many bacteria and can be characterized by an activity against E. coli of at least 0.5 ⁇ g / ml, preferably at least 12 or at least 25 ⁇ g / ml (minimal microbicidal concentration or MMK) in the suspension test).
• a preferred antiseptic biguanide according to this invention is poly (imino [iminocarbonyl] iminopolymethylene), the use of poly (hexamethylene) biguanide (PHMB), also referred to as polyhexanide, being particularly preferred as antiseptic biguanide.
• PHMB poly (hexamethylene) biguanide
• antiseptic biguanides also includes metabolites and / or prodrugs of the antiseptic biguanides Antiseptic biguanides may be present as racemates or pure isoforms.
• the foamed articles of polyurethane foams or the compositions according to the present invention preferably contain antiseptic biguanide and / or its salt, preferably the hydrochloride, in a concentration of 0.01 to 20% by weight, the concentration being from 0.1 to 5 Gew% is particularly advantageous.
• the biguanide can have any molecular weight distribution.
• the solids contents were determined according to DIN-EN ISO 3251.
• NCO contents were determined volumetrically in accordance with DIN EN ISO 11909, unless expressly stated otherwise.
• the indicated viscosities were determined by means of rotational viscometry according to DIN 53019 at 23 ° C. using a rotational viscometer from Anton Paar Germany GmbH, Ostf ⁇ ldern, DE.
• Diaminosulphonate NH 2 -CH 2 CH 2 -NH-CH 2 CH 2 -SO 3 Na (45% in water)
• Desmophen ® C2200 polycarbonate polyol, OH number 56 mg KOH / g, number average molecular weight 2000 g / mol (Bayer MaterialScience AG, Leverkusen, DE)
• PolyTHF ® 2000 Polytetramethylenglykolpolyol, OH number 56 mg KOH / g, number average molecular weight 2000 g / mol (BASF AG,
• PolyTHF ® 1000 Polytetramethylenglykolpolyol, OH number 112 mg KOH / g, number-average number average molecular weight 1000 g / mol (BASF AG, Ludwigshafen, DE)
• Polyether LB 25 monofunctional ethylene oxide / propylene oxide based polyether number average molecular weight 2250 g / mol, OH number 25 mg KOH / g (Bayer MaterialScience AG, Leverkusen, DE)
• Pluronic ® PE 6800 EO / PO block copolymer (BASF AG, Ludwigshafen, DE)
• the determination of the average particle sizes (indicated by the number average) of the polyurethane dispersions was carried out by means of laser correlation spectroscopy (instrument: Malvern Catalyst 1000, Malver Inst. Limited).
• NCO value was reached.
• the finished prepolymer was dissolved with 4830 g of acetone and thereby cooled to 50 0 C and then a solution of 25.1 g Ethylenendiamm, 116.5 g of isophoronediamine, 61.7 g of diammosulfonate and 1030 g of water was added within 10 mm. The stirring time was 10 min. Then was dispersed by adding 1250 g of water. This was followed by removal of the solvent by distillation in vacuo.
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C): 241 mPas
• the finished prepolymer was dissolved with 1005 g of acetone and cooled to 50 0 C and then a solution of 5.70 ethylenediamine, 26.4 g of isophoronediamine, 9.18 g of diammosulfonate and 249.2 g of water within 10 mm zudo- Siert.
• the stirring time was 10 min. It was then dispersed by adding 216 g of water. This was followed by removal of the solvent by distillation in vacuo.
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C): 133 mPas
• LB 25 polyether were heated in a standard stirring apparatus at 70 0 C. Then, at 70 0 C within 5 min, a mixture of 237.0 g of hexamethylene carbonate and 313.2 g of isophorone diisocyanate were added and stirred at 120 0 C until the theoretical NCO value was reached.
• the finished prepolymer was dissolved with 4830 g of acetone while cooled to 50 0 C and then a solution of 36.9 g of 1, 4-diaminobutane,
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C.): 126 mPas
• the finished prepolymer was dissolved with 1010 g of acetone while cooled to 50 0 C and then a solution of 5,70 E-thylenediamine, 26.4 g of isophoronediamine, 14.0 g of diaminosulfonate and 250 g of water was added within 10 min. The stirring time was 10 min. Then, by adding 243 g
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C.): 57 mPas
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C): 84 mPas
• NCO value was reached.
• the finished prepolymer was dissolved with 4820 g of acetone while cooled to 50 0 C and then a solution of 27.3 g of ethylenediamine, 126.5 g of isophoronediamine, 67.0 g of diaminosulfonate and 1090 g of water was added within 10 min. The stirring time was 10 min. It was then dispersed by adding 1180 g of water. This was followed by removal of the solvent by distillation in vacuo.
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C): 286 mPas
• Polyurethane dispersion not according to the invention (no sulfonate groups, but only hydrophilization by non-ionic groups and carboxylate groups)
• the finished prepolymer was dissolved with 1010 g of acetone while cooled to 50 0 C and then a solution of 5.3 g of ethylenediamine, 24.4 g of isophoronediamine, 11.9 g of KV 1386 (40% aqueous solution of the sodium salt of N - (2-aminoethyl) - / 3-alanine, BASF AG, Ludwigshafen, DE) and 204 g of water added within 10 min. The stirring time was 10 min. Then, by adding 235 g of water to dispersed. This was followed by removal of the solvent by distillation in vacuo. Due to the high viscosity, a total of 250 g of water had to be added
• the resulting white dispersion had the following properties:
• Viscosity (viscometer, 23 ° C): 162 mPas
• Polyurethane dispersion not according to the invention (no sulfonate groups, but only
• LB 25 polyether were heated in a standard stirring apparatus at 70 0 C. Subsequently, a mixture of 49.7 g of hexamethylene diisocyanate and 65.6 g of isophorone diisocyanate was added at 70 0 C within 5 min and stirred at 120 0 C until the theoretical NCO value was reached.
• the finished prepolymer was dissolved with 1010 g of acetone and thereby cooled to 50 0 C and then a solution of 5.3 g of ethylenediamine, 21.8 g
• the resulting white dispersion had the following properties: Solids content: 52.2%
• Viscosity (viscometer, 23 ° C): 176 mPas
• the amounts of the polyurethane dispersion shown in the table 1 2 (Example 2) of the foam auxiliary agent Pluronic ® 6800 and the crosslinker were mixed and beaten using a commercially available hand stirrer (stirrer made of bent wire) in 10 minutes on a foam volume of 500 ml. Thereafter, the foams were spread on a release paper (wet film thickness: 4 mm). The foams were dried at 120 ° C. for 20 min and at 150 ° C. for 10 min. Pure white, hydrophilic foams with good mechanical properties and a fine pore structure were consistently obtained.
• the crosslinked foams also showed good water resistance.
• Acrafix ML hexamethoxymethylmelamine, Lanxess AG, Leverkusen DE
• Bayhydur 305 non-ionically hydrophilicized polyisocyanate based on hexamethylene diisocyanate, NCO content: 16.2%, Bayer MaterialScience AG, Leverkusen, DE
• Bayhydur 3100 nonionically hydrophilicized polyisocyanate based on hexamethylene diisocyanate, NCO content: 17.4% Bayer MaterialScience AG, Leverkusen, DE
• uncrosslinked foam was prepared, i. the use of a crosslinker was omitted.
• the uncrosslinked foam had a significantly lower water resistance (classification: "low") than the crosslinked foams of Examples 7-9.

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