Polyurethane dispersions

Abstract

The present invention relates to aqueous polyurethane dispersion containing at least one polyurethane, at least one organic dialkyl dicarbonate and at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these, further to the use of organic dialkyl dicarbonates for reducing microorganisms in an aqueous polyurethane dispersion, to a process for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms and to an article, cosmetic, coating, adhesive layer, coating formulation, adhesive formulation and / or cosmetic formulation obtainable therefrom.

Description

[0001] Polyurethane dispersions

[0002] The present invention relates to aqueous polyurethane dispersion containing at least one polyurethane, at least one organic dialkyl dicarbonate and at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these, further to the use of organic dialkyl dicarbonates for reducing microorganisms in an aqueous polyurethane dispersion, to a process for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms and to an article, cosmetic, coating, adhesive layer, coating formulation, adhesive formulation and / or cosmetic formulation obtainable therefrom.

[0003] Aqueous polyurethane dispersions, the addition of reagents having biocidal effects to preserve the polyurethane dispersions and the use of corresponding polyurethane dispersions are already known to those skilled in the art.

[0004] DE 19810819 discloses a process for treating liquid coating materials which comprise an in-can preservative. For this purpose, a reagent is added to the coating material immediately before use thereof, which decomposes the in-can preservative. Isothiazolinones are disclosed as suitable in-can preservatives; examples of suitable in-can preservatives are in particular chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone or methyltrimethyleneisothiazolinone.

[0005] US 2018 / 258300 discloses a printer ink composition comprising synthetic resin particles, for example polyurethane particles, pigments, glycol ethers and water. This composition may comprise additives, for example preservatives. The water with which the composition is produced may be treated in advance with hydrogen peroxide to remove microbes.

[0006] US 2017 / 156340 discloses antimicrobial coatings for implants, medical instruments, devices or hospital equipment. For this purpose, a polymer provided with a metal derivative is attached to the surface, which develops a biocidal effect in the presence of hydrogen peroxide.

[0007] JP 2018 053 170 discloses a printer ink containing a polyurethane dispersion of crosslinkable, urethane-based resin. The printer ink may also comprise preservatives. Furthermore, the water used to produce the printer ink may be treated with hydrogen peroxide beforehand to make it sterile. However, it has been found that peroxides such as hydrogen peroxide are not compatible with other biocides readily suitable for in-can preservation, for example isothiazolinones such as 5-chloro-2- methylisothiazolinone and 2-methylisothiazolinone.

[0008] It is an object of the present invention to provide an aqueous polyurethane dispersion which not only exhibits consistently high quality and consistently good performance up to the time of its processing, in particular by the customer, but is also largely free from microorganisms, such as for example bacteria, yeasts and moulds, during its processing, in particular for producing articles, cosmetics, coatings, adhesives or adhesive layers. To ensure long-term stabilization of the aqueous polyurethane dispersion it shall be possible to allow treatment in the presence of established biocides such as isothiazolinones such as 5-chloro-2-methylisothiazolinone and 2-methylisothiazolinone. These may be employed for in-can preservation but have the disadvantage that the employable amounts are very limited if a classification of the final product as a hazardous substance or hazardous material is to be avoided. Therefore, they are less optimal for utilization as a biocide for initial germ reduction. Compatibility of the germ-reducing treatment in the context of the object with isothiazolinones is therefore necessary.

[0009] It is a further object to provide a process for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms.

[0010] These objects are achieved by the aqueous polyurethane dispersion according to the invention containing at least one polyurethane, at least one organic dialkyl dicarbonate and at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di -tert-butyl dicarbonate and / or mixtures of at least two of these.

[0011] These objects are further achieved by the process according to the invention for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms comprising at least the steps of

[0012] (A) providing an aqueous polyurethane dispersion containing at least one polyurethane;

[0013] (B) treating the aqueous polyurethane dispersion from step (A) with at least one organic dialkyl dicarbonate selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these; to obtain an aqueous polyurethane dispersion comprising a reduced amount of microorganisms. These objects are also achieved by the use according to the invention of at least one organic dialkyl dicarbonate for reducing microorganisms in an aqueous polyurethane dispersion containing at least one polyurethane, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these.

[0014] In the context of the invention, "reduced amount of microorganisms" or "for reducing microorganisms" is understood as meaning that the number of microorganisms in the aqueous polyurethane dispersion defined as a colony-forming unit (CFU) after 72 hours of growth in the respective test system is reduced compared to the CFU density of the untreated polyurethane dispersion, is preferably less than 10 000 CFU / ml, is particularly preferably less than 1000 CFU / ml, is yet more preferably less than 100 CFU / ml, in each case according to DIN EN ISO 6222 (K5) 1999- 07. However it is generally possible to employ direct or indirect means for quantification suitable for the respective type of microorganisms. In the case of bacteria for example it is possible to use the BacTrac analysis described in the experimental section or surface-viable count, plaque assay or a dip test. Preferably, the amount of microorganisms is reduced to such an extent that the BacTrac 4300 from SY-EAB Gerate GmbH indicates no germ load after 24 hours, preferably 48 hours, especially preferably after 72 hours test duration in the aqueous polyurethane dispersion. Compared to the original polyurethane dispersion the germ load based on colony-forming unit (CFU) is reduced here by at least 80%, preferably by at least 99%, determined with the BacTrac 4300 from SY-EAB Gerate GmbH as also described in the experimental section of this document. This is based on the amount of microorganisms in the aqueous polyurethane dispersion at the commencement of the measurement (time 0). To this end 1 ml of the polyurethane-polyurea-polyurethane dispersion was poured into the BiMedia 001C measuring cell (order number 41-440011). The measuring cell was sealed with the screw cap (order number 41-440012+) and placed in the measurement unit of the BacTrac 4300 which was temperature-controlled to 30°C.

[0015] It has surprisingly been found that the aqueous polyurethane dispersions according to the invention remain germ-free over a period of at least 6 months as a result of the initial germ reduction or germ elimination, optionally in combination with in-can preservation biocides, provided they are in an originally sealed container. It is also possible here to employ aqueous polyurethane dispersions which would not be employable according to the current prior art because a classical biocide treatment of polyurethane dispersions would require such high amounts of biocide that a typically unacceptable chemicals legislation labelling of the resulting polyurethane dispersion would have to be effected.

[0016] The present invention is described in detail below. In the context of the present invention the word “a” in connection with countable parameters is to be understood as meaning a numeral only when this is stated explicitly (for instance by the expression "precisely one"). When reference is made hereinbelow for example to “ a polyisocyanate” the word “a” is to be understood as meaning merely the indefinite article and not the number one, this therefore also encompasses an embodiment in which two or more, for example structurally dissimilar, polyisocyanates are present.

[0017] “Aqueous polyurethane dispersion” in the context of the invention is understood as meaning an aqueous polyurethane dispersion, aqueous emulsion, aqueous suspension, or an intermediate state / intermediate form thereof, preferably an aqueous polyurethane dispersion, aqueous emulsion and / or aqueous suspension. The term “polyurethane dispersion” is particularly preferably understood as meaning an aqueous emulsion and / or an aqueous suspension. The term “polyurethane dispersion” refers to both polyurethane dispersions and polyurethane-(poly)urea-polyurethane dispersions. The term “polyurethane” refers to both polyurethane and polyurethane-(poly)urea.

[0018] In the context of the invention the term "microorganisms" is understood as meaning for example algae, bacteria, fungi, yeasts and viruses, preferably bacteria, fungi, yeasts and yet more preferably bacteria and / or yeasts.

[0019] According to the invention the terms “comprising” or “containing” preferably mean “essentially consisting of’ and particularly preferably “consisting of’. It should be noted that the features listed individually in the claims can be combined with one another in any technically advantageous manner (even across category boundaries, for example between process and apparatus) and specify further configurations of the invention. The description additionally characterizes and specifies the invention.

[0020] It should also be noted that a conjunction “and / or” used herein, between two features and linking them to one another is always to be interpreted in such a way that in a first configuration of the subject matter of the invention only the first feature can be present, in a second configuration only the second feature can be present and in a third configuration both the first and the second feature can be present.

[0021] The aqueous polyurethane dispersion according to the invention contains at least one polyurethane, at least one organic dialkyl dicarbonate and at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these. In a preferred embodiment the aqueous polyurethane dispersion is an aqueous polyurethane dispersion comprising a reduced amount of microorganisms.

[0022] According to the invention it is generally possible to employ any polyurethane known to those skilled in the art in the aqueous polyurethane dispersion.

[0023] In a preferred embodiment the at least one polyurethane has been obtained or is obtainable by reacting the following synthesis components:

[0024] (a) at least one diol and / or polyol component;

[0025] (b) at least one di- and / or polyisocyanate component;

[0026] (c) at least one component comprising at least one hydrophilizing group;

[0027] (d) optionally mono-, di- and / or triamino-functional and / or hydroxyamino-functional compounds; and

[0028] (e) optionally other isocyanate-reactive compounds; wherein the components (a), (b), (c), (d) and (e) are distinct.

[0029] Suitable diol and / or polyol components (a) are compounds having at least two isocyanate-reactive hydrogen atoms and a number-average molecular weight (determined by GPC in THF as eluent at 23°C, calibrated using polystyrene standards) of preferably 62 to 18000 g / mol, particularly preferably 62 to 4000 g / mol.

[0030] Examples of suitable structural components (a) are polyether polyols, polyester polyols, polycarbonate polyols, polylactones and polyamides. Preferred polyols (a) preferably have 2 to 4, particularly preferably 2 to 3 hydroxyl groups, especially preferably 2 hydroxyl groups. Mixtures of various such compounds are also possible.

[0031] While the teaching of the present invention may in principle be realized with any dispersed polyurethane or polyurethane-urea polymer the at least one polyurethane present in the aqueous polyurethane dispersion according to the invention preferably comprises as component (a) one or more polyester polyols and / or one or more polyether polyols and / or one or more polycarbonate polyols. In a preferred embodiment the least one polyurethane is based on poly ether polyols and / or polyester polyols and / or polycarbonate polyols. In a further preferred embodiment the at least one polyurethane is based on at least one polyester polyol, preferably polyester diol, and / or at least one polyether polyol, preferably polyether diol, and / or at least one polycarbonate polyol, preferably polycarbonate diol. Suitable polyester polyols are in particular linear polyester diols or also sparsely branched polyester polyols, as can be produced in a known manner from aliphatic, cycloaliphatic or aromatic di- or polycarboxylic acids such as succinic acid, methylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, terephthalic acid, isophthalic acid, o-phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, maleic acid, fumaric acid, malonic acid or trimellitic acid, and acid anhydrides such as o-phthalic, trimellitic or succinic anhydride or mixtures thereof with polyhydric alcohols, such as ethanediol, di-, tri-, tetraethylene glycol, propane- 1,2-diol, di-, tri-, tetrapropylene glycol, propane-1, 3-diol, butane- 1,4-diol, butane- 1,3 -diol, butane-2,3-diol, pentane-l,5-diol, hexane- 1,6-diol, 2, 2-dimethylpropane-l, 3-diol, 1,4-dihydroxycyclohexane, 1,4- dimethylolcyclohexane, octane-1, 8-diol, decane- 1,10-diol, dodecane- 1, 12-diol or mixtures thereof, optionally with the additional use of higher-functional polyols such as trimethylolpropane, glycerol or pentaerythritol. Cycloaliphatic and / or aromatic di- and polyhydroxyl compounds are of course also suitable as polyhydric alcohols for producing the polyester polyols. In place of the free polycarboxylic acid, it is also possible to use for the production of the polyesters the corresponding polycarboxylic anhydrides or corresponding polycarboxylic esters of lower alcohols or mixtures thereof.

[0032] The polyester polyols may also be homopolymers or copolymers of lactones preferably obtained by addition reaction of lactones or lactone mixtures, such as butyrolactone, s-caprolactonc and / or methyl-8-caprolactone, onto suitable di- and / or higher-functional starter molecules, for example the low-molecular-weight polyhydric alcohols mentioned above as synthesis components for polyester polyols. Preference is given to the corresponding polymers of 8-caprolactone.

[0033] Polycarbonates having hydroxyl groups are also suitable as polyhydroxyl components (a), for example those that can be produced by reacting diols such as butane- 1,4-diol and / or hexane- 1,6-diol with diaryl carbonates, for example diphenyl carbonate, dialkyl carbonates, for example dimethyl carbonate, or phosgene. The at least partial use of polycarbonates having hydroxyl groups can improve the resistance to hydrolysis of the polyurethane or polyurethane-urea-polyurethane dispersion adhesives in the event that the polyurethane dispersions according to the invention are used for producing adhesives.

[0034] Examples of suitable polyether polyols are the polyaddition products of styrene oxides, of ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, epichlorohydrin, and mixed addition and grafting products thereof, and also the polyether polyols obtained by condensation of polyhydric alcohols or mixtures of the same and obtained by alkoxylation of polyhydric alcohols, amines and amino alcohols. Polyether polyols particularly suitable as structural components (a) are homopolymers, copolymers, and graft polymers of propylene oxide, of ethylene oxide and of tetrahydrofiiran, which are accessible by addition of the epoxides mentioned or of tetrahydrofiiran onto low-molecular-weight diols or triols, such as those mentioned above as structural components for polyester polyols, or onto higher-functional low-molecular-weight polyols such as pentaerythritol or sugar, or onto water.

[0035] Suitable components (a) are also low-molecular-weight diols, triols, and / or tetraols such as ethanediol, di-, tri-, tetraethylene glycol, propane- 1,2-diol, di-, tri-, tetrapropylene glycol, propane- 1,3-diol, butane- 1,4-diol, butane-l,3-diol, butane-2,3-diol, pentane-l,5-diol, hexane- 1,6-diol, 2,2- dimethylpropane-l,3-diol, 1,4-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, octane-1, 8-diol, decane- 1,10-diol, dodecane- 1,12-diol, neopentyl glycol, cyclohexane- 1,4-diol, cyclohexane- 1,4- dimethanol, 1,4-, 1,3-, 1,2-dihydroxybenzene or 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), TCD diol, trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol or mixtures thereof, optionally with the additional use of other diols or triols not mentioned.

[0036] Polyols used may also be reaction products of the polyols mentioned, in particular of the low- molecular-weight polyols, with ethylene oxide and / or propylene oxide.

[0037] The low-molecular-weight components (a) preferably have a molecular weight of 62 to 400 g / mol and are further preferably used in combination with the polyester polyols, polylactones, polyether polyols and / or polycarbonate polyols described above.

[0038] The polyol component (a) is preferably present in the at least one polyurethane employed according to the invention in an amount of 20% to 94% by weight, particularly preferably in an amount of 30% to 90% by weight and very particularly preferably in an amount of 65% to 90% by weight, wherein the components (a), (b), (c), optionally (d) and optionally (e) present in each case sum to 100% by weight.

[0039] Suitable components (b) include any organic compounds having at least two free isocyanate groups per molecule. Preference is given to using diisocyanates of general formula Y(NCO)2, wherein Y is a divalent aliphatic hydrocarbon radical having 4 to 12 carbon atoms, a divalent cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, a divalent aromatic hydrocarbon radical having 6 to 15 carbon atoms or a divalent araliphatic hydrocarbon radical having 7 to 15 carbon atoms.

[0040] Examples of such diisocyanates to be used with preference are tetramethylene diisocyanate, methylpentamethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, l-isocyanato-3,3,5-trimethyl-5- isocyanatomethylcyclohexane (isophorone diisocyanate; IPDI), 4,4'- diisocyanatodicyclohexylmethane, 4,4'-diisocyanato-2,2-dicyclohexylpropane, 1,4- diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'- diisocyanatodiphenylmethane, 2,2'- and 2,4'-diisocyanatodiphenylmethane, tetramethylxylylene diisocyanate, p-xylylene diisocyanate, p-isopropylidene diisocyanate, and mixtures consisting of these compounds.

[0041] In addition to these simple diisocyanates, polyisocyanates containing heteroatoms in the radical linking the isocyanate groups and / or having a functionality of more than 2 isocyanate groups per molecule are also suitable. The former are polyisocyanates having a uretdione, isocyanurate, urethane, allophanate, biuret, carbodiimide, iminooxadiazinedione, and / or oxadiazinetrione structure that are produced for example by modification of simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates and composed of at least two diisocyanates. An example of an unmodified polyisocyanate having more than 2 isocyanate groups per molecule is, for example, 4- isocyanatomethyloctane 1,8 -diisocyanate (nonane triisocyanate).

[0042] Preferred diisocyanates (b) are pentamethylene diisocyanate, methylpentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1- isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'- diisocyanatodicyclohexylmethane , 1,3- and l,4-bis(isocyanatomethyl)benzene, 1,3- and 1 ,4-bis( 1- isocyanato-l-methylethyl)benzene, bis(4-(l-isocyanato-l-methylethyl)phenyl) carbonate, 4,4'- diisocyanato-2,2-dicyclohexylpropane, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6- diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2 ,2'- and 2,4'- diisocyanatodiphenylmethane, tetramethylxylylene diisocyanate, p-xylylene diisocyanate, p- isopropylidene diisocyanate, and mixtures consisting of these compounds.

[0043] Particularly preferred components (b) are 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, hexamethylene diisocyanate, 4,4'-diisocyanatodicyclohexylmethane, l-isocyanato-3,3,5-trimethyl- 5-isocyanatomethylcyclohexane, and also mixtures consisting of these compounds.

[0044] Component (b) is present in the at least one polyurethane employed according to the invention in an amount of generally 5% to 60% by weight, preferably 6% to 45% by weight and particularly preferably 7% to 25% by weight, wherein the components (a), (b), (c), optionally (d) and optionally (e) present in each case sum to 100% by weight.

[0045] Suitable components (c) are, for example, components comprising sulfonate or carboxylate groups, for example diamino compounds or dihydroxy compounds additionally bearing sulfonate and / or carboxylate groups, for example the sodium, lithium, potassium, tert-amine salts of N-(2- aminoethyl)-2-aminoethanesulfonic acid, N-(3-aminopropyl)-2-aminoethanesulfonic acid, N-(3- aminopropyl)-3-aminopropanesulfonic acid, N-(2-aminoethyl)-3-aminopropanesulfonic acid, the analogous carboxylic acids, dimethylolpropionic acid, dimethylolbutyric acid, the reaction products in the sense of a Michael addition of 1 mol of diamine, for example ethane- 1,2-diamine or isophoronediamine, with 2 mol of acrylic acid or maleic acid.

[0046] The acids are preferably used directly in the form of their sulfonate or carboxylate salts. However, it is also possible to add some or all of the neutralizing agents necessary for salt formation only during or after production of the polyurethanes.

[0047] Tertiary amines particularly readily suitable and preferred for salt formation include for example triethylamine, dimethylcyclohexylamine and / or ethyldiisopropylamine. Other amines may also be used for salt formation, for example ammonia, diethanolamine, triethanolamine, dimethylethanolamine, methyldiethanolamine, aminomethylpropanol and also mixtures of the amines cited and also other amines. These amines are advantageously added only after formation of the prepolymer composed of the components (a) and (b).

[0048] It is also possible to use, for neutralization purposes, other neutralizing agents, for example sodium, potassium, lithium and calcium hydroxides.

[0049] Further suitable components (c) are non-ionically hydrophilizing, mono- or difimctional polyethers based on alcohol- or amine-started ethylene oxide polymers or ethylene oxide / propylene oxide copolymers, for example polyether LB 25 (Covestro Deutschland AG, Leverkusen, Germany), diols having a polyether side-chain containing ethylene oxide units (for example Ymer N120, Perstorp Holding AB, Malmo, Sweden) or MPEG 750, i.e. methoxypolyethylene glycol having a molecular weight of 750 g / mol, obtainable for example under the trade name Pluriol® 750 from BASF SE, Germany.

[0050] Preferred components (c) are N-(2-aminoethyl)-2-aminoethanesulfonate, N-(2-aminoethyl)-2- aminoethanecarboxylate, and the salts of dimethylolpropionic acid and dimethylolbutyric acid.

[0051] Component (c) is present in the at least one polyurethane employed according to the invention preferably in an amount of 0. 1% to 15% by weight, particularly preferably 0.5% to 10% by weight, very particularly preferably 0.8% to 5% by weight and yet more preferably 0.9% to 3.0% by weight, wherein the components (a), (b), (c), optionally (d) and optionally (e) present in each case sum to 100% by weight.

[0052] Suitable components (d) according to the invention are mono-, di-, trifunctional amines and / or mono- , di-, trifunctional hydroxyamines, for example aliphatic and / or alicyclic primary and / or secondary monoamines, for example ethylamine, diethylamine, the isomeric propyl- and butylamines, higher linear aliphatic monoamines and cycloaliphatic monoamines, for example cyclohexylamine. Further examples are amino alcohols, i.e. compounds containing amino and hydroxyl groups in the same molecule, for example ethanolamine, N-methylethanolamine, diethanolamine, diisopropanolamine, l,3-diamino-2 -propanol, N-(2-hydroxyethyl)ethylenediamine, N,N-bis(2- hydroxyethyl)ethylenediamine and 2-propanolamine.

[0053] Further examples are diamines and triamines, for example ethane- 1,2-diamine, hexamethylene- 1,6- diamine, l-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (isophoronediamine), piperazine, 1,4- diaminocyclohexane, bis(4-aminocyclohexyl)methane, and diethylenetriamine. Adipic dihydrazide, hydrazine, and hydrazine hydrate are additionally suitable. It is of course also possible to use mixtures of a plurality of the compounds (d) mentioned, optionally also together with compounds (d) that are not mentioned.

[0054] Preferred components (d) are ethane- 1,2-diamine, l-amino-3,3,5-trimethyl-5- aminomethylcyclohexane, diethylenetriamine, diethanolamine, ethanolamine, N-(2- hydroxyethyl)ethylenediamine, and N,N-bis(2-hydroxyethyl)ethylenediamine.

[0055] Components (d) serve as di- or trifunctional chain extenders, preferably in order to build up higher molecular weights, or in the form of monofunctional compounds to limit molecular weights, and / or optionally as a means of incorporating additional reactive groups such as free hydroxyl groups. If (poly)amines (d) are not used, the polymers formed are pure polyurethanes which more preferably do not contain any urea groups.

[0056] Component (d) is preferably present in the at least one polyurethane employed according to the invention in an amount of 0% to 10% by weight, particularly preferably 0% to 5% by weight and very particularly preferably 0.2% to 3% by weight, wherein the components (a), (b), (c), optionally (d) and optionally (e) present in each case sum to 100% by weight.

[0057] Components (e) for optional co-use according to the invention may be for example aliphatic, cycloaliphatic or aromatic monoalcohols having 2 to 22 C atoms, for example ethanol, butanol, hexanol, cyclohexanol, isobutanol, benzyl alcohol, stearyl alcohol, 2-ethylethanol.

[0058] Components (e) may preferably be present in the at least one polyurethane employed according to the invention in an amount of 0% to 20% by weight, particularly preferably 0% to 10% by weight, wherein the components (a), (b), (c), optionally (d) and optionally (e) present in each case sum to 100% by weight. The lateral and / or terminal carboxyl groups can in principle be incorporated into the polymer skeleton via any of the synthesis components (a) to (e). They are preferably incorporated via components (c), (d) and / or (e).

[0059] Incorporation via component (c) can be accomplished for example by using dimethylolpropionic acid or dimethylolbutyric acid in the absence of neutralizing agent or with neutralizing agent added in a substoichiometric amount.

[0060] Compounds suitable for the incorporation of carboxyl groups as component (d) are, for example, those which contain only one isocyanate-reactive amino group and thus, in the production of the polyurethanes according to the invention, result in terminal carboxyl groups by reaction with the isocyanate component. Linear aliphatic, branched aliphatic, aliphatic-aromatic and aromatic aminocarboxylic acids are suitable. Examples include aminocarboxylic acids having a primary or secondary amino group, such as alanine, 6-aminohexanoic acid, aminoundecanoic acid, 8- aminooctanoic acid, 5 -aminopentanoic acid, 4-aminobutyric acid, aminobenzoic acid, 4- aminomethylcyclohexanecarboxylic acid, 2-aminohexanoic acid, 4-aminocyclohexanecarboxylic acid, 12-aminododecanoic acid and / or 9-aminononacarboxylic acid.

[0061] Compounds suitable for the incorporation of carboxyl groups as component (d) are, for example, diaminocarboxylic acids which each have 2 isocyanate-reactive amino groups and thus, in the production of the at least one polyurethane, result in lateral carboxyl groups by reaction with the isocyanate component. Examples of these are lysine, arginine and / or histidine.

[0062] Compounds suitable for the incorporation of carboxyl groups as component (e) are, for example, hydroxycarboxylic acids which contain only one hydroxyl group, for example hydroxypivalic acid, hydroxyacetic acid and / or 2-hydroxypropanoic acid.

[0063] The production of the aqueous polyurethane dispersions according to the invention may employ all processes known from the prior art such as emulsifier, shear force, acetone, prepolymer mixing, melt emulsifying, ketimine and solid spontaneous dispersing processes or derivatives thereof. A summary of these methods can be found in Methoden der organischen Chemie (Houben-Weyl, Erweiterungs- und Folgebande zur 4. Auflage, volume E20, H. Bartl and J. Falbe, Stuttgart, New York, Thieme 1987, pages 1671 to 1682). According to the invention, preference is given to the melt emulsification, prepolymer mixing, and acetone processes. Particular preference is given to the acetone process. The use and implementation of the acetone process is prior art and is known to those skilled in the art from EP -A 0 232 778, for example. In a preferred embodiment the at least one polyurethane is present in an amount of 5% to 64% by weight, preferably 30% to 60% by weight, particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion.

[0064] In a preferred embodiment the water content of the aqueous polyurethane dispersions according to the invention is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion.

[0065] The aqueous polyurethane dispersion according to the invention contains at least one compound having a biocidal effect. In the context of the present invention, "having a biocidal effect” means that the corresponding compound can control microorganisms, in particular bacteria and / or fungi, can prevent them from multiplying or kill them and must appear in the list of the relevant substances and the associated suppliers of substances and products according to Article 95 of the Biocidal Products Regulation (BPR) [Regulation (EU) No. 334 / 2014, 11 March 2014] (20.03.2024 version). The at least one compound having a biocidal effect is distinct from the organic dialkyl dicarbonate.

[0066] Suitable compounds having a biocidal effect include all biocides known to those skilled in the art, for example algicides, bactericides, fungicides against fungi, insecticides, antifungal agents against yeasts and virucides.

[0067] Compounds having a biocidal effect preferably include one or more bactericides, fungicides against fungi, antifungals against yeasts and / or a mixture of at least two of these. The employed compound having a biocidal effect is preferably at least one biocide for in-can preservation.

[0068] In a preferred embodiment the at least one compound having a biocidal effect is a bactericide, fungicide and / or algicide, preferably at least one isothiazolinone, particularly preferably selected from the group consisting of chloromethylisothiazolinone (CMIT), methylisothiazolinone (MIT), benzisothiazolinone, octylisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two of these, yet more preferably selected from the group consisting of 5- chloro-2-methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof. The at least one compound having a biocidal effect is distinct from the at least one organic dialkyl dicarbonate.

[0069] In a preferred embodiment the at least one compound having a biocidal effect is present in an amount of 1 to 1000 mg / kg based on the total aqueous polyurethane dispersion.

[0070] The at least one organic dialkyl dicarbonate has the formula R-O-C(=O)-O-C(=O)-O-R', wherein R and R' are alkyl groups and R and R’ are preferably identical. Examples include dimethyl dicarbonate, diethyl dicarbonate and di-tert-butyl dicarbonate, preferably dimethyl dicarbonate and diethyl dicarbonate, very particularly preferably dimethyl dicarbonate.

[0071] In a preferred embodiment the at least one organic dialkyl dicarbonate is dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, preferably dimethyl dicarbonate.

[0072] In a preferred embodiment the at least one organic dialkyl dicarbonate is present in an amount of 0.1 g / kg to 50 g / kg, preferably of 0.1 g / kg to 20 g / kg, based on the total aqueous polyurethane dispersion.

[0073] In addition to the aforementioned components the aqueous polyurethane dispersion according to the invention may contain any component appearing suitable to a person skilled in the art. Examples of components additionally present include binders known in coatings and adhesives technology, assistant and additive substances, in particular emulsifiers and light stabilizers, especially UV absorbers, also fillers and auxiliaries, in particular anti-settling agents, defoaming and / or wetting agents, flow auxiliaries, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, especially pigments, dyes or matting agents, tackifiers, so-called tackifiers, or mixtures thereof.

[0074] In a preferred embodiment the aqueous polyurethane dispersion additionally contains components selected from binders, assistant and additive substances, fillers, auxiliaries, flow auxiliaries, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0075] The present invention further relates to a process for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms comprising at least the steps of:

[0076] (A) providing an aqueous polyurethane dispersion containing at least one polyurethane;

[0077] (B) treating the aqueous polyurethane dispersion from step (A) with at least one organic dialkyl dicarbonate selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these; to obtain an aqueous polyurethane dispersion comprising a reduced amount of microorganisms.

[0078] Details and preferred embodiments of the organic dialkyl dicarbonate and of the at least one compound having a biocidal effect are already described further above and apply correspondingly to the process according to the invention.

[0079] Details and preferred embodiments of the aqueous polyurethane dispersion provided in step (A) of the process according to the invention are already described further above and apply correspondingly to the process according to the invention. The aqueous polyurethane dispersion contains microorganisms in a different amount provided said dispersion has not been produced and packaged under sterile conditions. The aqueous polyurethane dispersion provided in step (A) contains at least one polyurethane and microorganisms. The aqueous polyurethane dispersion provided in step (A) differs from the aqueous polyurethane dispersion obtained by step (B) in that the amount of microorganisms in the aqueous polyurethane dispersion after step (B) is reduced / smaller compared to the provided aqueous polyurethane dispersion in step (A).

[0080] In the context of the present invention "providing” means that the aqueous polyurethane dispersion may be present in any form which appears suitable to those skilled in the art and in which it is possible to be treated according to step (B) of the process according to the invention. The aqueous polyurethane dispersion is preferably provided in a container or reactor, for example a stirred reactor. The addition of the at least one organic dialkyl dicarbonate may further also be carried out after transferring the aqueous polyurethane dispersion into a mixing vessel, in particular fitted with a stirrer or recirculation pump. The addition of the at least one organic dialkyl dicarbonate and the treatment of the aqueous polyurethane dispersion with at least one organic dialkyl dicarbonate may also be carried out directly into the delivery container of the polyurethane dispersion.

[0081] According to the invention the aqueous polyurethane dispersion has the concentrations of ingredients described further above. However, according to the invention it is also possible for the aqueous polyurethane dispersion to be diluted or concentrated before step (A). Suitable concentrations of the at least one polyurethane present are here 5% to 64% by weight, preferably 30% to 60% by weight, very particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion. In a preferred embodiment the water content in the aqueous polyurethane dispersions before step (A) is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion.

[0082] According to the invention the aqueous polyurethane dispersion may be mixed with at least one further aqueous polymer dispersion, for example with an aqueous polyurethane dispersion of at least one further film-forming polymer, before step (B) of the process according to the invention.

[0083] Step (B) of the process according to the invention can generally be carried out at any temperature that appears suitable to those skilled in the art. In a preferred embodiment step (B) is carried out at 1°C to 100°C, preferably at 5°C to 50°C, particularly preferably at 10°C to 30°C.

[0084] Step (B) of the process according to the invention can generally be carried out at any pressure that appears suitable to those skilled in the art, preferably at atmospheric pressure. In step (B) the aqueous polyurethane dispersion may preferably be stirred, in particular using apparatuses known to those skilled in the art, in particular propeller stirrers, anchor stirrers, dissolver discs, helical stirrers, jet stirrers, for example Visco-Jet®. The mixing and / or dissolution in step (B) of the process according to the invention may also be carried out by pumped recirculation of the aqueous polyurethane dispersion (A) using, for example, peristaltic pumps, diaphragm pumps, eccentric screw pumps.

[0085] In the treatment in step (B), reaction of the at least one organic dialkyl dicarbonate in water, i.e. the hydrolysis with the water of the polyurethane dispersion, liberates at least one alcohol. Examples are the liberation of ethanol from diethyl dicarbonate or methanol from dimethyl dicarbonate. These alcohols may be removed from the product, for example by distillation, or may optionally also remain in the product mixture in whole or in part. The carbon dioxide formed in the reaction of the at least one organic dialkyl dicarbonate in water, i.e. the hydrolysis with the water of the polyurethane- polyurea-polyurethane dispersion, either remains physically dissolved in the polyurethane dispersion, reacts with water to form carbonic acid or to form carbonates and / or may be removed from the polyurethane dispersion. Partial or complete removal of the carbon dioxide formed is possible by heating the polyurethane dispersion or by applying vacuum.

[0086] The reaction time after addition of the at least one organic dialkyl dicarbonate to the polyurethane dispersion is preferably one minute to 24 hours. The batch is preferably actively mixed, for example stirred, during this time. It is also possible to provide a post-reaction phase without active stirring and this may also be carried out in the delivery container.

[0087] Before adding the at least one organic dialkyl dicarbonate to the aqueous polyurethane dispersion the dialkyl dicarbonate may be dissolved in a suitable solvent. Examples include water-miscible solvents, for example water, monoalcohols, for example methanol or ethanol, glycols, for example propylene glycol, ketones, for example acetone, or N-alkyl pyrrolidones such as N-methyl-2- pyrrolidone, N-ethyl -2 -pyrrolidone or N-butyl -2 -pyrrolidone. It is preferable to employ solvents which do not decompose the dialkyl dicarbonate or deactivate its effect.

[0088] Further additives may also be added to the dialkyl dicarbonate before the addition to the aqueous polyurethane dispersion. In a preferred variant the dialkyl dicarbonate is added in pure form, i.e. without further premixing or pre-dilution.

[0089] In a preferred embodiment metered addition of the at least one organic dialkyl dicarbonate is effected via a nozzle. In a further preferred embodiment metered addition of the at least one organic dialkyl dicarbonate is effected via a mixing apparatus. In a further preferred embodiment the added amount and addition rate of the at least one organic dialkyl dicarbonate is controlled using a liquid flowmeter unit and a metered addition unit coupled thereto. Step (B) of the process according to the invention affords an aqueous polyurethane dispersion largely free of the employed organic dialkyl dicarbonate. In a preferred embodiment the aqueous polyurethane dispersion no longer contains any organic dialkyl dicarbonate 24 hours, preferably 12 hours, yet more preferably 6 hours, yet more preferably 3 hours and most preferably 1 hour after step

[0090] (B) of the process according to the invention, wherein the content of dialkyl dicarbonate is determined by chromatography, preferably by HPLC (High Performance Liquid Chromatography). The aqueous polyurethane dispersion obtained preferably no longer contains any organic dialkyl dicarbonate before the application or use thereof.

[0091] According to the invention it is possible to add at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate before, after or at the same time as step (B). This has the advantage that the amount of microorganisms may be reduced still further and the period in which the polyurethane dispersion comprises only a small amount of microorganisms is markedly extended once again.

[0092] In a preferred embodiment at least the following step (C) is performed before, after or at the same time as step (B):

[0093] (C) adding at least one compound having a biocidal effect, which is distinct from the at least one organic dialkyl dicarbonate, wherein step (C) is preferably performed before or at the same time as step (B).

[0094] However, it is also possible according to the invention for the aqueous polyurethane dispersion obtained in step (B) or step (C) to be supplied to further workup steps, for example the addition of thickeners, pigments, colour pastes, further processing auxiliaries, for example defoamers, wetting auxiliaries, coagulation auxiliaries and / or stabilizers, for example further antioxidants and UV stabilizers, that are suitable for the further processing. Processes for adding the components mentioned are known per se to those skilled in the art.

[0095] According to the invention it is possible that after step (B) or step (C) the aqueous polyurethane dispersion is used to produce articles, cosmetics, coatings; adhesive layers or adhesives, wherein if a step (C) is present this must be performed after or at the same time as step (B).

[0096] In a preferred embodiment at least the following step (D) is performed after step (B) or step (C):

[0097] (D) producing articles, cosmetics, coatings; adhesive layers or adhesives from the aqueous polyurethane dispersion comprising a reduced amount of microorganisms obtained in step (B) or step (C). In a further preferred embodiment at least the following step (D) is performed after step (B) or step

[0098] (C) if step (C) is carried out after step (B):

[0099] (D) producing articles, cosmetics, coatings; adhesive layers or adhesives from the aqueous polyurethane dispersion comprising a reduced amount of microorganisms obtained in step (B) or step (C).

[0100] Appropriate processes carried out in step (D) of the process according to the invention are known per se to those skilled in the art, for example

[0101] • dip coating, in particular for the manufacture of gloves, preferably for use in the medical field,

[0102] • production of aqueous adhesive polyurethane dispersions that are processed with and without crosslinkers, for example isocyanate or polycarbodiimide crosslinkers,

[0103] • production of latent-reactive adhesive layers, adhesive films or adhesive powders, for example described in EP -A 0 922 720 or EP 2 099 840 Bl,

[0104] • production and / or coating of textiles, leather or synthetic leather and microfiber-based textiles or synthetic leather,

[0105] • use of polyurethane dispersion in hairspray, sunscreens, etc.,

[0106] • coatings on plastics, metallic materials, wood, composite materials, ceramic materials, mineral substrates such as stone

[0107] • as well as on previously coated substrates.

[0108] Preferred articles according to the invention are selected for example from articles produced by dip coating, for example disposable gloves or condoms, covers or so-called sleeves for medical devices, probes, endoscopes, coated textiles, bandages, films for wound dressings, medical foams or so-called wearable patches.

[0109] Cosmetics preferred according to the invention are selected, for example, from hairspray, sunscreen cream, conditioner or mascara, etc., more preferably the at least one polyurethane used here serves as a film former.

[0110] Coatings preferred according to the invention are selected, for example, from primer, filler, base coat and top coat systems, coatings of wood, metal and plastics, textiles, leather, artificial leather, each in various industries, for example in cars, large vehicles, ACE (agricultural, construction & earth moving equipment), industrial coatings, furniture or fiberglass sizing.

[0111] Adhesives preferred according to the invention are for example selected from polyurethane dispersion adhesives processed as 1- or 2-component systems, non-reactive and reactive adhesive films, adhesive powders or adhesive layers, in each case applied to substrate surfaces. The present invention also relates to an aqueous polyurethane dispersion comprising a reduced amount of microorganisms obtainable or obtained by the process according to the invention.

[0112] The present invention also relates to an aqueous polyurethane dispersion containing at least one polyurethane and optionally at least one compound having a biocidal effect, characterized in that the number of microorganisms in the aqueous polyurethane dispersion, defined as a colony-forming unit (CFU) after 72 hours of growth in the test system is less than 10 000 CFU / ml, is preferably less than 1000 CFU / ml, is particularly preferably less than 100 CFU / ml, in each case according to DIN EN ISO 6222 (K5) 1999-07.

[0113] The present invention further also relates to the use of at least one organic dialkyl dicarbonate for reducing microorganisms in an aqueous polyurethane dispersion containing at least one polyurethane, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these. The aqueous polyurethane dispersion contains at least one polyurethane and microorganisms prior to the treatment / use with the organic dialkyl dicarbonate.

[0114] Details and preferred embodiments of the aqueous polyurethane dispersion and of the organic dialkyl dicarbonate and of the at least one compound having a biocidal effect are already described further above and apply correspondingly to the use according to the invention.

[0115] In a preferred embodiment the aqueous polyurethane dispersion further contains at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate.

[0116] The present invention also relates to the use according to the invention of the at least one organic dialkyl dicarbonate in the process according to the invention for reducing the amount of microorganisms in an aqueous polyurethane dispersion.

[0117] The present invention also relates to the use according to the invention of the at least one organic dialkyl dicarbonate in a process for reducing the amount of microorganisms in an aqueous polyurethane dispersion. The process steps for reducing the amount of microorganisms in an aqueous polyurethane dispersion may be the same here as those described above.

[0118] The present invention also relates to articles, cosmetics, coatings, adhesive layers, coating formulations, adhesive formulations and / or cosmetic formulations containing at least one aqueous polyurethane dispersion according to the invention or an aqueous polyurethane dispersion according to the invention comprising a reduced amount of microorganisms. Various aspects of the subject matter described herein are set out in the following numbered clauses: Clause 1. Aqueous polyurethane dispersion containing at least one polyurethane, at least one organic dialkyl dicarbonate and at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these.

[0119] Clause 2. The aqueous polyurethane dispersion of clause 1, characterized in that the at least one compound having a biocidal effect is a bactericide, fungicide and / or algicide, preferably at least one isothiazolinone, particularly preferably selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, methyltrimethyleneisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two of these, yet more preferably selected from the group consisting of 5-chloro- 2 -methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof.

[0120] Clause 3. The aqueous polyurethane dispersion of clause 1 or clause 2, characterized in that the at least one organic dialkyl dicarbonate is dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof.

[0121] Clause 4. The aqueous polyurethane dispersion of any of clauses 1 to 3, characterized in that the at least one compound having a biocidal effect is present in an amount of 1 to 1000 mg / kg based on the total aqueous polyurethane dispersion.

[0122] Clause 5. The aqueous polyurethane dispersion of any of clauses 1 to 4, characterized in that the at least one polyurethane is present in an amount of 5% to 64% by weight, preferably 30% to 60% by weight, particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion.

[0123] Clause 6. The aqueous polyurethane dispersion of any of clauses 1 to 5, characterized in that the aqueous polyurethane dispersion additionally contains components selected from binders, assistant and additive substances, fdlers, auxiliaries, flow auxiliaries, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0124] Clause 7. The aqueous polyurethane dispersion of any of clauses 1 to 6, characterized in that the at least one polyurethane has been obtained or is obtainable by reacting the following synthesis components:

[0125] (a) at least one diol and / or polyol component;

[0126] (b) at least one di- and / or polyisocyanate component;

[0127] (c) at least one component comprising at least one hydrophilizing group;

[0128] (d) optionally mono-, di- and / or triamino-functional and / or hydroxyamino-functional compounds; and

[0129] (e) optionally other isocyanate-reactive compounds; wherein the components (a), (b), (c), (d) and (e) are distinct.

[0130] Clause 8. The aqueous polyurethane dispersion of any of clauses 1 to 7, characterized in that the at least one organic dialkyl dicarbonate is present in an amount of 0.001 g / kg to 100 g / kg, preferably from 0.1 g / kg to 50 g / kg, particularly preferably of 0. 1 g / kg to 20 g / kg, based on the total aqueous polyurethane dispersion.

[0131] Clause 9. The aqueous polyurethane dispersion of any of clauses 1 to 8, characterized in that the water content of the aqueous polyurethane dispersions is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion.

[0132] Clause 10. Use of at least one organic dialkyl dicarbonate for reducing microorganisms in an aqueous polyurethane dispersion containing at least one polyurethane, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert- butyl dicarbonate and / or mixtures of at least two of these.

[0133] Clause 11. The use of clause 10, characterized in that the aqueous polyurethane dispersion further contains at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate.

[0134] Clause 12. The use of clause 11, characterized in that the at least one compound having a biocidal effect is a bactericide, fungicide and / or algicide, preferably at least one isothiazolinone, particularly preferably selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, methyltrimethyleneisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two of these, yet more preferably selected from the group consisting of 5-chloro- 2 -methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof.

[0135] Clause 13. The use of any of clauses 10 to 12, characterized in that the at least one organic dialkyl dicarbonate is dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof.

[0136] Clause 14. The use of any of clauses 11 to 13, characterized in that the at least one compound having a biocidal effect is present in an amount of 1 to 1000 mg / kg based on the total aqueous polyurethane dispersion.

[0137] Clause 15. The use of any of clauses 10 to 14, characterized in that the at least one polyurethane is present in an amount of 5% to 64% by weight, preferably 30% to 60% by weight, particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion. Clause 16. The use of any of clauses 10 to 15, characterized in that the aqueous polyurethane dispersion additionally contains components selected from binders, assistant and additive substances, fdlers, auxiliaries, flow auxiliaries, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof. Clause 17. The use of any of clauses 10 to 16, characterized in that the at least one polyurethane has been obtained or is obtainable by reacting the following synthesis components:

[0138] (a) at least one diol and / or polyol component;

[0139] (b) at least one di- and / or polyisocyanate component;

[0140] (c) at least one component comprising at least one hydrophilizing group;

[0141] (d) optionally mono-, di- and / or triamino-functional and / or hydroxyamino-functional compounds; and

[0142] (e) optionally other isocyanate-reactive compounds; wherein the components (a), (b), (c), (d) and (e) are distinct.

[0143] Clause 18. The use of any of clauses 10 to 17, characterized in that the at least one organic dialkyl dicarbonate is present in an amount of 0.001 g / kg to 100 g / kg, preferably from 0. 1 g / kg to 50 g / kg, particularly preferably of 0.1 g / kg to 20 g / kg, based on the total aqueous polyurethane dispersion.

[0144] Clause 19. The use of any of clauses 10 to 18, characterized in that the water content of the aqueous polyurethane dispersions is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion.

[0145] Clause 20. Process for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms, comprising at least the steps of:

[0146] (A) providing an aqueous polyurethane dispersion containing at least one polyurethane;

[0147] (B) treating the aqueous polyurethane dispersion from step (A) with at least one organic dialkyl dicarbonate selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these; to obtain the aqueous polyurethane dispersion comprising a reduced amount of microorganisms.

[0148] Clause 21. The process of clause 20, characterized in that at least the following step (C) is performed before, after or at the same time as step (B):

[0149] (C) adding at least one compound having a biocidal effect, which is distinct from the at least one organic dialkyl dicarbonate, wherein step (C) is preferably performed before or at the same time as step (B).

[0150] Clause 22. The process of clause 20 or clause 21, characterized in that at least the following step

[0151] (D) is performed after step (B) or step (C):

[0152] (D) producing articles, cosmetics, coatings; adhesive layers or adhesives from the aqueous polyurethane dispersion comprising a reduced amount of microorganisms obtained in step (B) or step (C).

[0153] Clause 23. The process of any of clauses 20 to 22, characterized in that step (B) is carried out at 1°C to 100°C, preferably at 5°C to 50°C, particularly preferably at 10°C to 30°C. Clause 24. The process of any of clauses 21 to 23, characterized in that the at least one compound having a biocidal effect is a bactericide, fungicide and / or algicide, preferably at least one isothiazolinone, particularly preferably selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, methyltrimethyleneisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two of these, yet more preferably selected from the group consisting of 5-chloro- 2 -methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof.

[0154] Clause 25. The process of any of clauses 21 to 24, characterized in that the at least one compound having a biocidal effect is present in an amount of 1 to 1000 mg / kg based on the total aqueous polyurethane dispersion.

[0155] Clause 26. The process of any of clauses 20 to 25, characterized in that the at least one organic dialkyl dicarbonate is dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof.

[0156] Clause 27. The process of any of clauses 20 to 26, characterized in that the at least one polyurethane is present in an amount of 5% to 64% by weight, preferably 30% to 60% by weight, particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion.

[0157] Clause 28. The process of any of clauses 20 to 27, characterized in that the aqueous polyurethane dispersion additionally contains components selected from binders, assistant and additive substances, fdlers, auxiliaries, flow auxiliaries, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0158] Clause 29. The process of any of clauses 20 to 28, characterized in that the at least one polyurethane has been obtained or is obtainable by reacting the following synthesis components:

[0159] (a) at least one diol and / or polyol component;

[0160] (b) at least one di- and / or polyisocyanate component;

[0161] (c) at least one component comprising at least one hydrophilizing group;

[0162] (d) optionally mono-, di- and / or triamino-functional and / or hydroxyamino-functional compounds; and

[0163] (e) optionally other isocyanate-reactive compounds; wherein the components (a), (b), (c), (d) and (e) are distinct.

[0164] Clause 30. The process of any of clauses 20 to 29, characterized in that the at least one organic dialkyl dicarbonate is present in an amount of 0.001 g / kg to 100 g / kg, preferably from 0. 1 g / kg to 50 g / kg, particularly preferably of 0.1 g / kg to 20 g / kg, based on the total aqueous polyurethane dispersion.

[0165] Clause 31. The process of any of clauses 20 to 30, characterized in that the water content of the aqueous polyurethane dispersions is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion. Clause 32. Aqueous polyurethane dispersion obtainable or obtained by the process of any of clauses 10 to 31.

[0166] Clause 33. Article, cosmetic, coating, adhesive layer, coating formulation, adhesive formulation and / or cosmetic formulation containing at least one aqueous polyurethane dispersion of any of clauses 1 to 9 or an aqueous polyurethane dispersion comprising a reduced amount of microorganisms of clause 32.

[0167] The present invention will now be elucidated by reference to working examples.

[0168] Experimental

[0169] Materials and sources

[0170] The employed polyurethane dispersions (Dispercoll® U 53, Dispercoll® U 54) derive from Covestro Deutschland AG, Leverkusen, DE

[0171] All other chemicals were obtained from Sigma-Aldrich Chemie GmbH, Taufkirchen, DE unless otherwise stated.

[0172] DMDC: Dimethyl dicarbonate

[0173] DEDC: Diethyl dicarbonate

[0174] CMIT : Chloromethylisothiazolinone (5 -chloro-2-methylisothiazolinone)

[0175] MIT: Methylisothiazolinone (2-methylisothiazolinone)

[0176] Preventol® D7: 1.5% by weight aqueous solution of a mixture of 5-chloro-2- methylisothiazolinone / 2-methylisothiazolinone (CAS 55965-84-9), Lanxess Deutschland AG, DE

[0177] Unless otherwise stated all percentages are percentages by weight (% by weight).

[0178] Unless otherwise stated all procedures and analytical measurements were performed at a temperature of 23°C (room temperature).

[0179] Methods:

[0180] Determination of the germ status of the polyurethane-polyurea-polyurethane dispersions:

[0181] The determination of the contamination or the bacterial growth in the polyurethane-polyurea- polyurethane dispersions was carried out using the BacTrac 4300 from SY-LAB Gerate GmbH, Neupurkersdorf, Austria. To this end 1 ml of the polyurethane-polyurea-polyurethane dispersion was poured into the BiMedia 001C measuring cell. The measuring cell was sealed with the screw cap and placed in the measurement unit of the BacTrac 4300 which was temperature-controlled to 30°C.

[0182] The multiplication of the microorganisms in the polyurethane dispersion sample is accompanied by the increase in the metabolic products. The BacTrac 4300 measuring device uses the alternating current resistance (impedance) of the sample as a measure for determining the metabolic products. The threshold value (E) can be specified individually. If the threshold value (E) is exceeded the sample is considered to be non-sterile. For all measurements, the threshold value (E) was set at the value of 8 and the maximum measurement duration at 72 h. The temperature of the sample was 30°C during the measurement.

[0183] Description of diptest system for determining the germ load

[0184] For determining the total germ count as well as that of yeasts and moulds Mikrocount® combi dipslides (Schiilke&Mayr GmbH, Norderstedt, DE) were used based on DIN EN ISO 23321. The dipslides were immersed in the liquid material to be tested (polyurethane dispersion) and after drip- drying cultivated at 30°C for 3 days. The germ load was read using the colony density (number of microorganisms per ml) in the diagram or, in the case of low colony density, the colony count was determined.

[0185] Examples:

[0186] Experiment 1

[0187] A sample of the polyurethane dispersion Dispercoll® U53 was analysed for germs. A significant germ load was determined by dip test.

[0188] The sample was divided into 4 parts of 100 g of the polyurethane dispersion in each case . The samples were stirred in a vessel with a magnetic stirrer and the following was added: a) nothing b) 0.1 g of dimethyl dicarbonate c) 0.5 g of dimethyl dicarbonate d) 1.0 g of dimethyl dicarbonate

[0189] Each mixture was stirred at room temperature for 5 hours. After one day an analysis for germs was performed. Table 1 : Results of analysis of experiment 1

[0190] ** termination of analysis after 72 hours without determining a germ load

[0191] * Higher time values indicate lower germ growth in the test and therefore lower initial load of the sample. The samples were then stored at room temperature and after 8 and 18 days further germ determinations were performed.

[0192] Table 2: Results of the germ determination after 8 and 18 days

[0193] ** termination of analysis after 72 hours without determining a germ load Evaluation: Addition of as little as 0.1% by weight of DMDC (based on the mass of the polyurethane dispersion) achieved an initial reduction in the germ count. However, under these conditions germ multiplication set in again upon storage. The addition of 0.5 or 1.0% by weight of DMDC resulted in germ-free polyurethane dispersions even after 8 or 18 days of storage. Experiment 2

[0194] Another sample of the Dispercoll® U53 polyurethane dispersion was analysed for germs. A germ load was ascertained by dip test.

[0195] The sample was divided into 4 parts of 100 g of the polyurethane dispersion in each case . The samples were stirred in a vessel with a magnetic stirrer and the following was added: a) nothing b) 0.1 g of dimethyl dicarbonate c) 0.5 g of dimethyl dicarbonate d) 1.0 g of dimethyl dicarbonate Each mixture was stirred at room temperature for 5 hours.

[0196] Table 3 : Results of analysis of experiment 2

[0197] ** termination of analysis after 72 hours without determining a germ load

[0198] * Higher time values indicate lower germ growth in the test and therefore lower initial load of the sample.

[0199] Evaluation: Compared to the sample from batch 1 the employed polyurethane dispersion has a lower initial germ load. Addition of as little as 0.1% of DMDC achieved a reduction in the density of microorganisms to such an extent that colony-forming units were no longer detectable (sample b). Experiment 3

[0200] A sample of the contaminated polyurethane dispersion according to experiment 2 was used here.

[0201] The sample was divided into 4 parts of 100 g of the polyurethane dispersion in each case. The samples were stirred in a vessel with a magnetic stirrer and the following was added: a) nothing b) 0.1 g of diethyl dicarbonate c) 0.5 g of diethyl dicarbonate d) 1.0 g of diethyl dicarbonate

[0202] Each mixture was stirred at room temperature for 5 hours.

[0203] Table 4: Results of analysis of experiment 3

[0204] * Higher time values indicate lower germ growth in the test and therefore lower initial load of the sample.

[0205] Evaluation: A reduction in the content of microorganisms was also achieved with diethyl dicarbonate.

[0206] There were no noticeable changes to the polyurethane dispersions during and after the additions of the additives dimethyl dicarbonate and diethyl dicarbonate. Average particle size (measured by a Zetasizer, Malvern Panalytical Ltd, UK) and polyurethane dispersion viscosity (Haake Viscotester iQ, Fisher Scientific GmbH, Schwerte, DE) do not change significantly, but rather only within the range of typical variations of the analytical methods, after addition of the additive dimethyl dicarbonate. Films of the polyurethane dispersions were applied to glass plates (doctor blade 210 pm slot width) and dried at 50°C for 1 hour and then at 120°C for 1 hour. There were no visually detectable differences in flow, fdm quality or the color of the fdms after addition of the additive dimethyl dicarbonate compared to the films without addition of the additives.

[0207] Conclusion: Adding dialkyl dicarbonates efficiently reduced the germ count in polyurethane dispersions, in some cases to below the limit of detection. In the experiments dimethyl dicarbonate has proven more effective for reducing the germ count than diethyl dicarbonate.

[0208] Experiment 4

[0209] Compatibility of organic dicarbonates with biocidal active ingredients.

[0210] Polyurethane dispersions are often mixed with isothiazolinones to achieve longer-term container preservation against contamination, even for example upon entry of microorganisms after opening of the container.

[0211] A sample of Dispercoll U 54 was admixed with Preventol D7 and different amounts of DMDC were added at room temperature. After a wait time of one week the contents of biocidal active ingredient (CMIT and MIT) were determined by HPLC.

[0212] Table 5 : Results of analysis of experiment 4

[0213] Evaluation:

[0214] No detectable decomposition of the active ingredients chloromethylisothiazolinone and methylisothiazolinone through addition of dimethyl dicarbonate was observed. Comparative test 1

[0215] Compatibility of hydrogen peroxide with biocidal active ingredients

[0216] To test whether a polyurethane dispersion can analogously also be treated with hydrogen peroxide instead of with dialkyl dicarbonates to reduce the germ load without affecting the further biocidal active ingredients.

[0217] A sample of Dispercoll U 54 was admixed with Preventol D7 and different amounts of hydrogen peroxide (3% solution in water) were mixed in at room temperature. After a wait time of one week the contents of biocidal active ingredient were determined by HPLC.

[0218] Table 6: Results of the analysis of comparative test 1

[0219] Evaluation:

[0220] The active substances chloromethylisothiazolinone and methylisothiazolinone are decomposed by addition of hydrogen peroxide solution, even at very small addition amounts of hydrogen peroxide. In-can preservation with chloromethylisothiazolinone or methylisothiazolinone at the same time as treatment with hydrogen peroxide is thus not possible.

Claims

Claims1. Aqueous polyurethane dispersion containing at least one polyurethane, at least one organic dialkyl dicarbonate and at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di- tert-butyl dicarbonate and / or mixtures of at least two of these.

2. Use of at least one organic dialkyl dicarbonate for reducing microorganisms in an aqueous polyurethane dispersion containing at least one polyurethane, characterized in that the at least one organic dialkyl dicarbonate is selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di -tert-butyl dicarbonate and / or mixtures of at least two of these.

3. The use according to claim 2, characterized in that the aqueous polyurethane dispersion further contains at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate.

4. The use according to claim 3, characterized in that the at least one compound having a biocidal effect is a bactericide, fungicide and / or algicide, preferably at least one isothiazolinone, particularly preferably selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, methyltrimethyleneisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two of these, yet more preferably selected from the group consisting of 5-chloro-2-methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof.

5. The use according to claim 3 or claim 4, characterized in that the at least one compound having a biocidal effect is present in an amount of 1 to 1000 mg / kg based on the total aqueous polyurethane dispersion.

6. The use according to any of claims 2 to 5, characterized in that the at least one organic dialkyl dicarbonate is dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof.

7. The use according to any of claims 2 to 6, characterized in that the at least one polyurethane is present in an amount of 5% to 64% by weight, preferably 30% to 60% by weight, particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion.

8. The use according to any of claims 2 to 7, characterized in that the at least one polyurethane has been obtained or is obtainable by reacting the following synthesis components:(a) at least one diol and / or polyol component;(b) at least one di- and / or polyisocyanate component;(c) at least one component comprising at least one hydrophilizing group;(d) optionally mono-, di- and / or triamino-functional and / or hydroxyamino-functional compounds; and(e) optionally other isocyanate-reactive compounds; wherein the components (a), (b), (c), (d) and (e) are distinct.

9. The use according to any of claims 2 to 8, characterized in that the at least one organic dialkyl dicarbonate is present in an amount of 0.001 g / kg to 100 g / kg, preferably from 0. 1 g / kg to 50 g / kg, particularly preferably of 0.1 g / kg to 20 g / kg, based on the total aqueous polyurethane dispersion.

10. The use according to any of claims 2 to 9, characterized in that the water content of the aqueous polyurethane dispersions is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion.

11. Process for producing an aqueous polyurethane dispersion comprising a reduced amount of microorganisms, comprising at least the steps of:(A) providing an aqueous polyurethane dispersion containing at least one polyurethane;(B) treating the aqueous polyurethane dispersion from step (A) with at least one organic dialkyl dicarbonate selected from the group consisting of dimethyl dicarbonate, diethyl dicarbonate, dipropyl dicarbonate, diisopropyl dicarbonate, methyl ethyl dicarbonate, di-tert-butyl dicarbonate and / or mixtures of at least two of these; to obtain the aqueous polyurethane dispersion comprising a reduced amount of microorganisms.

12. The process according to claim 11, characterized in that at least the following step (C) is performed before, after or at the same time as step (B):(C) adding at least one compound having a biocidal effect, which is distinct from the at least one organic dialkyl dicarbonate, wherein step (C) is preferably performed before or at the same time as step (B).

13. The process according to either of claims 11 or 12, characterized in that at least the following step (D) is performed after step (B) or step (C):(D) producing articles, cosmetics, coatings; adhesive layers or adhesives from the aqueous polyurethane dispersion comprising a reduced amount of microorganisms obtained in step (B) or step (C).

14. The process according to any of claims 11 to 13, characterized in that step (B) is carried out at 1°C to 100°C, preferably at 5°C to 50°C, particularly preferably at 10°C to 30°C.

15. The process according to any of claims 12 to 14, characterized in that the at least one compound having a biocidal effect is a bactericide, fungicide and / or algicide, preferably at least one isothiazolinone, particularly preferably selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, methyltrimethyleneisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two of these, yet more preferably selected from the group consisting of 5-chloro-2-methylisothiazolinone / 2- methylisothiazolinone and / or mixtures thereof.

16. The process according to any of claims 12 to 15, characterized in that the at least one compound having a biocidal effect is present in an amount of 1 to 1000 mg / kg based on the total aqueous polyurethane dispersion.

17. The process according to any of claims 11 to 16, characterized in that the at least one organic dialkyl dicarbonate is dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof.

18. The process according to any of claims 11 to 17, characterized in that the at least one polyurethane is present in an amount of 5% to 64% by weight, preferably 30% to 60% by weight, particularly preferably 40% to 50% by weight, in each case based on the total aqueous polyurethane dispersion.

19. The process according to any of claims 11 to 18, characterized in that the at least one polyurethane has been obtained or is obtainable by reacting the following synthesis components:(a) at least one diol and / or polyol component;(b) at least one di- and / or polyisocyanate component;(c) at least one component comprising at least one hydrophilizing group;(d) optionally mono-, di- and / or triamino-functional and / or hydroxyamino-functional compounds; and(e) optionally other isocyanate-reactive compounds; wherein the components (a), (b), (c), (d) and (e) are distinct.

20. The process according to any of claims 11 to 19, characterized in that the at least one organic dialkyl dicarbonate is present in an amount of 0.001 g / kg to 100 g / kg, preferably from 0. 1 g / kg to 50 g / kg, particularly preferably of 0.1 g / kg to 20 g / kg, based on the total aqueous polyurethane dispersion.

21. The process according to any of claims 11 to 20, characterized in that the water content of the aqueous polyurethane dispersions is in an amount of 36% to 95% by weight, preferably 40% to 70% by weight, particularly preferably 50% to 60% by weight, in each case based on the total aqueous polyurethane dispersion.

22. Aqueous polyurethane dispersion obtainable or obtained by the process according to any of claims 11 to 21.

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