Dispersions having a reduced content of free thermally eliminable, isocyanate-reactive blocking agents

Abstract

The present invention relates to the use of at least one organic dialkyl dicarbonate for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent. The invention also relates to a process for producing an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, to an aqueous crosslinker dispersion which is obtained or is obtainable by the process according to the invention, and also to an article, coating, adhesive layer, coating formulation and / or adhesive formulation which is obtainable therefrom.

Description

[0001] 2024PF30060 - Foreign Countries

[0002] - 1 -

[0003] Dispersions having a reduced content of free thermally eliminable, isocyanate-reactive blocking agents

[0004] The present invention relates to the use of at least one organic dialkyl dicarbonate for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent. The invention also relates to a process for producing an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanatereactive blocking agents, to an aqueous crosslinker dispersion which is obtained or is obtainable by the process according to the invention, and also to an article, coating, adhesive layer, coating formulation and / or adhesive formulation which is obtainable therefrom.

[0005] Aqueous dispersions comprising crosslinker with isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent inevitably contain a certain amount of free blocking agent. This free blocking agent is present as residual, unreacted material that has not formed covalent chemical bonds with the isocyanate functional groups of the crosslinker. The presence of this free blocking agent may result from various factors, including but not limited to, incomplete reaction during the blocking process, equilibrium conditions, adhesion of blocking agent to the equipment above the reactor filling level or the deliberate addition of excess blocking agent to ensure complete reaction of isocyanate groups.

[0006] Chemically blocking of the reactive isocyanate groups in a crosslinker to result in a crosslinker that can be formulated into a stable system with standard co-reactants and additives is known in the art and is described in for example the handbook Polyurethanes, Coatings, Adhesives and Sealants, 2nd Revised Edition, by Ulrich Meier-Westhues, Karsten Danielmeier, Peter Kruppa and Edward P. Squiller. Chemical crosslinking is initiated after application by curing at elevated temperature; the blocking agent is cleaved at elevated cure temperature, allowing the isocyanate-reactive co-reactant to replace the blocking agent resulting in a cured system. Many thermally eliminable, isocyanatereactive blocking agents are classified as hazardous substances; therefore, the remaining content of these substances in aqueous crosslinker dispersions should ideally be kept as low as possible. Generally speaking, the thermally eliminable, isocyanate-reactive blocking agents used in synthesis of crosslinker having blocked isocyanate groups have a boiling point of greater than 100°C (at 1 atm) or form an azeotrope with water and can therefore not be easily removed by distillation from aqueous systems.

[0007] It is an object of the present invention to provide an aqueous crosslinker dispersion having a low content of thermally eliminable, isocyanate-reactive blocking agents, which has consistently high quality and consistently good performance properties up to the time of its processing, in particular 2024PF30060 - Foreign Countries

[0008] - 2 - by the customer, and is also suitable for being processed in particular for the production of articles, coatings, adhesives or adhesive layers. To ensure long-term stabilization of the aqueous crosslinker dispersion, it should be possible to reduce the content of thermally eliminable, isocyanate-reactive blocking agents in the presence of established biocides such as isothiazolinones such as 5-chloro-2- methylisothiazolinone and 2-methylisothiazolinone.

[0009] It is a further obj ect of the present invention to provide a process for producing an aqueous crosslinker dispersion having a reduced amount of thermally eliminable, isocyanate-reactive blocking agents.

[0010] These objects are achieved by the use according to the invention of at least one organic dialkyl dicarbonate for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent, wherein the thermally eliminable, isocyanate-reactive blocking agents is preferably selected from pyrazoles, oximes and mixtures thereof.

[0011] These objects are further achieved by the process according to the invention for producing an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, comprising at least the steps of:

[0012] (A) providing an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent;

[0013] (B) treating the aqueous crosslinker dispersion from step (A) with at least one organic dialkyl dicarbonate; to obtain an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents.

[0014] These objects are further achieved by the aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, which is obtained or is obtainable by the process according to the invention.

[0015] Surprisingly, it was found that the use according to the invention, and also the process according to the invention, made it possible to reduce the content of thermally eliminable, isocyanate-reactive blocking agents in aqueous crosslinker dispersions by using at least one organic dialkyl dicarbonate, without reducing the quality and performance properties of the dispersion. It is further possible to reduce the content of thermally eliminable, isocyanate-reactive blocking agents in the presence of 2024PF30060 - Foreign Countries

[0016] - 3 - established biocides such as isothiazolinones, thereby making it possible to reduce operating steps and optimize production operations.

[0017] The present invention is described in detail below.

[0018] In the context of the invention, “reducing the content of thermally eliminable, isocyanate-reactive blocking agents” or “reduced content of thermally eliminable, isocyanate-reactive blocking agents” is understood to mean that the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion is lower 24 hours after the addition or use of the at least one organic dialkyl dicarbonate than, or relative to, the content of thermally eliminable, isocyanatereactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate. In the context of the invention, “reducing the content of thermally eliminable, isocyanate-reactive blocking agents” or “reduced content of thermally eliminable, isocyanate-reactive blocking agents” is preferably understood to mean that the isocyanate-reactive group or at least one isocyanate-reactive group in the thermally eliminable, isocyanate-reactive blocking agent have reacted with the at least one organic dialkyl dicarbonate thereby forming new covalent bonds. The at least one thermally eliminable, isocyanate-reactive blocking agent is distinct from the at least one crosslinker. Preferably, the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is reduced by more than 80% by weight, particularly preferably more than 90% by weight, more preferably more than 95% by weight, yet more preferably more than 98% by weight, relative to the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate. Preferably, the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is in the range from 0% by weight to 0. 1% by weight, particularly preferably in the range from 0% by weight to 0.01% by weight, relative to the total weight of the aqueous dispersion as 100% by weight. The content or concentration of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion is / was determined or measured as follows:

[0019] The content of free, i.e. not chemically reacted, thermally eliminable, isocyanate-reactive blocking agent is determined by means of high-performance liquid chromatography with mass spectrometry coupling (HPLC-MS) using reversed phase columns (RP columns) with water as running medium. Detection is carried out via electrospray ionisation in positive mode (ESI+). Alternative analytical methods for quantification of the content not chemically reacted, thermally eliminable, isocyanatereactive blocking agent might be apply when appropriate. 2024PF30060 - Foreign Countries

[0020] - 4 -

[0021] In the context of the present invention, the word “a”or “an” in connection with countable parameters is to be understood as meaning the number “one” 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 covers an embodiment in which two or more, for example structurally dissimilar, polyisocyanates are present.

[0022] “Aqueous dispersion” in the context of the invention means an aqueous dispersion, aqueous emulsion, aqueous suspension, or an intermediate state / intermediate form thereof, which comprises a significant amount of water, typically more than 20% by weight in relation to the total aqueous dispersion. Preferably, “aqueous dispersion” in the context of the invention means an aqueous dispersion, aqueous emulsion and / or aqueous suspension. Particularly preferably, the term “aqueous dispersion” means an aqueous emulsion and / or an aqueous suspension.

[0023] According to the invention, the terms “comprising” or “containing” preferably mean “consisting essentially of’ and particularly preferably mean “consisting of’. It should be noted that the features listed individually in the claims can be combined with one another in any technically useful way (even across category boundaries, for example between method and device) and demonstrate further configurations of the invention. The description additionally characterizes and specifies the invention.

[0024] 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.

[0025] In the present invention, the at least one thermally eliminable, isocyanate-reactive blocking agent present in the dispersion comprises thermally eliminable, isocyanate-reactive blocking agent that exists as residual, unreacted material that has not formed covalent chemical bonds with isocyanate functional groups present in the components used in the synthesis of the crosslinker. Preferably, the at least one thermally eliminable, isocyanate-reactive blocking agent present in the dispersion is thermally eliminable, isocyanate-reactive blocking agent that exists as residual, unreacted material that has not formed covalent chemical bonds with isocyanate functional groups present in the components used in the synthesis of the crosslinker.

[0026] The present invention relates to the use of at least one organic dialkyl dicarbonate for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker 2024PF30060 - Foreign Countries

[0027] - 5 - dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent.

[0028] In a preferred embodiment, the thermally eliminable, isocyanate-reactive blocking agent is apyrazole and / or an oxime. A preferred pyrazole is 3,5-dimethylpyrazole. Preferred oximes are 2-butanone oxime and / or acetone oxime.

[0029] The present invention encompasses the use of crosslinkers wherein isocyanate functional groups have been blocked with one or more isocyanate-reactive blocking agents. Any such blocked crosslinker can be employed in the context of this invention, provided it is in the form of an aqueous dispersion. It should be noted that aqueous dispersions of such blocked crosslinkers are well-known to those skilled in the art of crosslinker chemistry. The selection and application of appropriate blocking agents, as well as methods for preparing these aqueous dispersions, are within the purview of a person having ordinary skill in the field.

[0030] In a preferred embodiment, the at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, was obtained or is obtainable by reacting the following synthesis components:

[0031] (a) optionally at least one diol and / or polyol component;

[0032] (b) at least one di- and / or polyisocyanate component;

[0033] (c) at least one thermally eliminable, isocyanate-reactive blocking agent;

[0034] (d) at least one isocyanate-reactive component comprising at least one hydrophilizing group; and

[0035] (e) optionally at least one mono-, di- and / or tri-amino-fimctional and / or hydroxyamino- fimctional compound; and

[0036] (f) optionally other isocyanate-reactive compounds, wherein the components (a), (b), (c), (d), (e) and (f) are distinct.

[0037] The proportions of the reaction partners are preferably selected such that the equivalent ratio of the isocyanate groups of isocyanate component (b) to the isocyanate-reactive groups of components (a), (c), (d), (e) and (f) is 1 :0.6 to 1: 1 .5 and with even more preferred preference is 1 :0.7 to 1: 1.3 and in particular preference is 1:0.7 to 1:0.97.

[0038] In a preferred embodiment, no component (a) is used. In this preferred embodiment, the crosslinker is preferably a polyisocyanate comprising isocyanate groups that are blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and being hydrophilized with for example an amino-functional building block. 2024PF30060 - Foreign Countries

[0039] - 6 -

[0040] In another preferred embodiment, the crosslinker is a polyurethane comprising isocyanate groups that are blocked with at least one thermally eliminable, isocyanate-reactive blocking agent. In this preferred embodiment, component (a) is not optional and is thus used as synthesis component for the preparation of the polyurethane. 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 18 000 g / mol, particularly preferably 62 to 4000 g / mol.

[0041] Examples of suitable synthesis 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, very particularly preferably 2 hydroxyl groups. Mixtures of various such compounds are also possible.

[0042] While the teaching of the present invention may in principle be realized with any dispersed polyurethane polymer comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, the at least one polyurethane comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent present in the aqueous polyurethane dispersion preferably contains 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 comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent is based on polyether polyols and / or polyester polyols and / or polycarbonate polyols. In a preferred embodiment, the at least one polyurethane comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent 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.

[0043] 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 2024PF30060 - Foreign Countries

[0044] - 7 - or pentaerythritol. Cycloaliphatic and / or aromatic di- and polyhydroxyl compounds are of course also suitable as polyhydric alcohols for producing the polyester polyols. Instead 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.

[0045] 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.

[0046] 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 polyurethane dispersion adhesives in the event that the aqueous polyurethane dispersions are used for producing adhesives.

[0047] 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 synthesis components (a) are homopolymers, copolymers and graft polymers of propylene oxide, ethylene oxide and tetrahydrofuran, which are accessible by addition of the epoxides mentioned or of tetrahydrofuran onto low-molecular-weight diols or triols, such as those mentioned above as synthesis components for polyester polyols, or onto higher-functional low-molecular-weight polyols such as pentaerythritol or sugar, or onto water.

[0048] 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. 2024PF30060 - Foreign Countries

[0049] - 8 -

[0050] 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.

[0051] 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 as described above.

[0052] The polyol component (a) is preferably present in the at least one polyurethane used according to the invention in an amount of 20% to 92% by weight, particularly preferably 30% to 90% by weight and very particularly preferably 65% to 80% by weight, wherein the sum of the components (a), (b), (c), (d) and optionally (e) and (f) present in each case amounts to 100% by weight.

[0053] Suitable as components (b) are 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.

[0054] Examples of such diisocyanates to be preferably used 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.

[0055] 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 prepared for example by modification of simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates and are 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). 2024PF30060 - Foreign Countries

[0056] - 9 -

[0057] 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,

[0058] 1.3- and l,4-bis(isocyanatomethyl)benzene, 1,3- and l,4-bis(l-isocyanato-l-methylethyl)benzene, bis(4-( 1 -isocyanato- 1 -methylethyl)phenyl) carbonate, 4,4'-diisocyanato-2,2-dicyclohexylpropane,

[0059] 1.4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'- diisocyanatodiphenylmethane, 2,2'- and 2,4'-diisocyanatodip, tetramethylxylylene diisocyanate, p- xylylene diisocyanate, p-isopropylidene diisocyanate, and mixtures consisting of these compounds.

[0060] More 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 and their polyisocyanurates or mixtures of their polyisocyanurates. Particularly preferred components (b) are hexamethylene diisocyanate, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane , 4,4'- diisocyanatodicyclohexylmethane and any mixture of at least two thereof and their polyisocyanurates or mixtures of their polyisocyanurates.

[0061] Component (b) is present in the at least one crosslinker used 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 65% by weight, wherein the sum of the components (a), (b), (c), (d) and optionally (e) and (f) present in each case amounts to 100% by weight.

[0062] Examples for thermally eliminable, isocyanate-reactive blocking agents (components (c)) are amines like diisopropylamine or JV-tert. -butyl -benzylamin, oximes like 2-butanon oxime, acetonoxime or cyclohexanonoxime, lactames like caprolactam, triazols or pyrazols like 3,5-dimethylpyrazole. Preferred thermally eliminable, isocyanate-reactive blocking agents (components (c)) are at least one oxime and / or at least one pyrazole. A preferred pyrazole is 3,5-dimethylpyrazole. Preferred oximes are 2-butanone oxime and / or acetone oxime. In case the thermally eliminable, isocyanate-reactive blocking agent (c) is 3,5-dimethylpyrazole, the crosslinker comprises isocyanate groups blocked with

[0063] 3.5-dimethylpyrazole. In case the thermally eliminable, isocyanate-reactive blocking agent (c) is 2- butanone oxime, the crosslinker comprises isocyanate groups blocked with 2-butanone oxime. In case the thermally eliminable, isocyanate-reactive blocking agent (c) is acetone oxime, the crosslinker comprises isocyanate groups blocked with acetone oxime.

[0064] The thermally eliminable, isocyanate-reactive blocking agent (c) is preferably present in the at least one crosslinker used according to the invention in an amount of generally 1% to 50% by weight, preferably 3% to 40% by weight and particularly preferably 5% to 35% by weight, wherein the sum 2024PF30060 - Foreign Countries

[0065] - 10 - of the components (a), (b), (c), (d) and optionally (e) and (f) present in each case amounts to 100% by weight.

[0066] Suitable components (d) 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, hydroxy pivalic 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.

[0067] 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 crosslinkers.

[0068] Tertiary amines particularly 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 which consists of the components (a) and (b).

[0069] It is also possible to use, for neutralization purposes, other neutralizing agents, for example sodium, potassium, lithium and calcium hydroxides.

[0070] Further suitable components (d) 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.

[0071] Preferred components (d) are N-(2-aminoethyl)-2-aminoethanesulfonate, N-(2-aminoethyl)-2- aminoethanecarboxylate, and the salts of dimethylolpropionic acid, hydroxy pivalic acid and dimethylolbutyric acid. 2024PF30060 - Foreign Countries

[0072] - 11 -

[0073] Component (d) is preferably present in the at least one crosslinker used according to the invention 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 sum of the components (a), (b), (c), (d) and optionally (e) and (f) present in each case amounts to 100% by weight.

[0074] Suitable components (e) for optional co-use 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 methylamine, 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, 1, 3 -diamino-2 -propanol, N-(2- hydroxyethyl)ethylenediamine, N,N-bis(2-hydroxyethyl)ethylenediamine and 2-propanolamine.

[0075] 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 (e) mentioned, optionally also together with compounds (e) that are not mentioned.

[0076] Preferred components (e) 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.

[0077] Components (e) 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. If (poly)amines (e) are not used and component (a) is used, the polymers formed are pure polyurethanes which more preferably do not contain any urea groups. If component (a) and (e) are used for preparing the polyurethane, the polyurethane is a polyurethane-polyurea. In the present invention, component (e) is preferably used for preparing the polyurethane-polyurea. Accordingly, the polyurethane used in the present invention is preferably a polyurethane-polyurea.

[0078] Component (e) is preferably present in the at least one polyurethane-polyurea used according to the invention in an amount of 0.1% to 10% by weight, particularly preferably 0.2% to 5% by weight and very particularly preferably 0.5% to 3% by weight, wherein the sum of the components (a), (b), (c), (d), (e) and optionally (f) present in each case amounts to 100% by weight. 2024PF30060 - Foreign Countries

[0079] - 12 -

[0080] Components (f) 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.

[0081] Components (f) may preferably be present in the at least one crosslinker used according to the invention in an amount of 0% to 20% by weight, particularly preferably 0% to 10% by weight, wherein the sum of the components (a), (b), (c), (d) and optionally (e) and (f) in each case amounts to 100% by weight.

[0082] The crosslinker preferably comprises lateral and / or terminal carboxyl groups which can in principle be incorporated into the polymer skeleton via any of the synthesis components (a) to (f). They are preferably incorporated via components (d), (e) and optionally (f).

[0083] Incorporation via component (d) 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.

[0084] Compounds suitable for the incorporation of carboxyl groups as component (e) are, for example, those which contain only one isocyanate-reactive amino group and thus, in the production of the crosslinkers 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.

[0085] Compounds suitable for the incorporation of carboxyl groups as component (e) are, for example, diaminocarboxylic acids which each have 2 isocyanate-reactive amino groups and thus, in the production of the at least one crosslinker, result in lateral carboxyl groups by reaction with the isocyanate component. Examples of these are lysine, arginine and / or histidine.

[0086] Compounds suitable for the incorporation of carboxyl groups as component (f) are, for example, hydroxycarboxylic acids which contain only one hydroxyl group, for example hydroxypivalic acid, hydroxyacetic acid and / or 2-hydroxypropanoic acid.

[0087] In order to produce the aqueous crosslinker dispersions, use may be made of any processes known from the prior art such as emulsifying shear force, acetone, prepolymer mixing, melt emulsification, ketimine and solid spontaneous dispersing processes or derivatives thereof. A summary of these 2024PF30060 - Foreign Countries

[0088] - 13 - methods can be found in Methoden der organischen Chemie [Methods of Organic Chemistry] (Houben-Weyl, Erweiterungs- und Folgebande zur 4. Auflage [Expansion and Supplementary Volumes for the 4th Edition], 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.

[0089] In a preferred embodiment, the at least one crosslinker 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 relative to the total aqueous crosslinker dispersion.

[0090] 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.

[0091] In a preferred embodiment, 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, diisobutyl dicarbonate and / or mixtures of at least two thereof; the organic dialkyl dicarbonate is preferably dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, and is particularly preferably dimethyl dicarbonate.

[0092] In a preferred embodiment, the at least one organic dialkyl dicarbonate is present in an amount of 0.001 g / kg to 100 g / kg, preferably of 0.1 g / kg to 50 g / kg, particularly preferably of 0.1 g / kg to 20 g / kg, relative to the total aqueous crosslinker dispersion.

[0093] In a preferred embodiment, the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate is in the range from 0.0001% by weight to 5% by weight, preferably from 0.01% by weight to 1% by weight, most preferred from 0.02% by weight to 0.1% by weight, relative to the total weight of the aqueous crosslinker dispersion as 100% by weight, wherein the thermally eliminable, isocyanate-reactive blocking agent or thermally eliminable, isocyanate-reactive blocking agents is / are preferably selected from pyrazoles and / or oximes.

[0094] In a preferred embodiment, the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is in the range from 0% by weight to 0.1% by weight, particularly preferably from 0% by weight to 0.01% by weight, relative to the total weight of the aqueous dispersion as 2024PF30060 - Foreign Countries

[0095] - 14 -

[0096] 100% by weight, wherein the thermally eliminable, isocyanate-reactive blocking agent or thermally eliminable, isocyanate-reactive blocking agents is / are preferably selected from pyrazoles and / or oximes.

[0097] In a preferred embodiment, the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is reduced by more than 80% by weight, preferably more than 90% by weight, particularly preferably more than 95% by weight, yet more preferably more than 98% by weight, relative to the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate as 100% by weight, wherein the thermally eliminable, isocyanate-reactive blocking agent or thermally eliminable, isocyanate-reactive blocking agents is / are preferably selected from pyrazoles and / or oximes.

[0098] The content of thermally eliminable, isocyanate-reactive blocking agent in the aqueous crosslinker dispersion is / was determined or measured as follows:

[0099] The concentrations of free, i.e., not chemically reacted, thermally eliminable, isocyanate-reactive blocking agent were determined by means of high-performance liquid chromatography with mass spectrometry coupling (HPLC-MS) using reversed phase columns (RP columns) with water as running medium. Detection is carried out via electrospray ionisation in positive mode (ESI+).

[0100] In a preferred embodiment, the aqueous crosslinker dispersion comprises at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, wherein the at least one compound having a biocidal effect is preferably a bactericide, fungicide and / or algicide, particularly preferably at least one isothiazolinone, is more preferably selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two thereof, is yet more preferably selected from the group consisting of 5-chloro-2- methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof, wherein the at least one compound having a biocidal effect is preferably present in an amount of 1 to 1000 mg / kg relative to the total aqueous crosslinker dispersion.

[0101] 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, and prevent them from reproducing or kill them.

[0102] Suitable compounds having a biocidal effect include all biocides known to those skilled in the art, for example algicides, bactericides, fungicides against fungi, insecticides, antimycotic agents against yeasts, and virucides. 2024PF30060 - Foreign Countries

[0103] - 15 -

[0104] The compound having a biocidal effect used is preferably at least one bactericide, fungicide against fungi, antimycotic agent against yeasts and / or a mixture of at least two thereof. The compound having a biocidal effect used is preferably at least one biocide for in-can preservation.

[0105] In addition to the aforementioned components the aqueous dispersion may also contain any component appearing suitable to a person skilled in the art. Examples of components additionally present include binders, biocides, in-can preservatives, assistant and additive substances, in particular emulsifiers and light stabilizers, in particular UV absorbers, also fillers and auxiliaries, in particular anti-settling agents, defoaming and / or wetting agents, levelling agents, reactive diluents , plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, in particular pigments, dyes or matting agents, tackifiers, or mixtures thereof, known in coatings and adhesives technology.

[0106] In a preferred embodiment, the aqueous crosslinker dispersion additionally contains components selected from binders, assistant and additive substances, fillers, auxiliaries, levelling agents, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0107] In a preferred embodiment of the use according to the invention, the at least one organic dialkyl dicarbonate is used in the process according to the invention for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion.

[0108] The present invention further relates to a process for producing an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, comprising at least the steps of:

[0109] (A) providing an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanatereactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent;

[0110] (B) treating the aqueous crosslinker dispersion from step (A) with at least one organic dialkyl dicarbonate; to obtain an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents.

[0111] Details and preferred embodiments of the organic dialkyl dicarbonate have already been described above and apply correspondingly to the use according to the invention. Details and preferred embodiments of the aqueous crosslinker dispersion provided in step (A) of the process according to the invention have already been described above and apply correspondingly to the process according to the invention. 2024PF30060 - Foreign Countries

[0112] - 16 -

[0113] The thermally eliminable, isocyanate-reactive blocking agent are preferably at least one pyrazole and / or at least one oxime. A preferred pyrazole is 3,5-dimethylpyrazole. Preferred oximes are 2- butanone oxime and / or acetone oxime.

[0114] In the context of the present invention, "providing” means that the aqueous crosslinker dispersion may be present in any form which appears suitable to those skilled in the art and in which it is possible to treat it according to step (B) of the process according to the invention. The aqueous crosslinker 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 crosslinker 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 crosslinker dispersion with at least one organic dialkyl dicarbonate may also be carried out directly in the delivery container of the dispersion.

[0115] According to the invention, the aqueous dispersion has the concentrations of ingredients described above. However, it is also possible according to the invention for the aqueous crosslinker dispersion to be diluted or concentrated before step (A). Suitable concentrations of the at least one crosslinker present are 5 to 64% by weight, preferably 30 to 60% by weight, very particularly preferably 40 to 50% by weight, in each case relative to the total aqueous crosslinker dispersion.

[0116] According to the invention, the aqueous crosslinker dispersion may be mixed with at least one further aqueous polymer dispersion, for example with an aqueous dispersion of at least one further filmforming polymer, before step (B) of the process according to the invention.

[0117] 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.

[0118] 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.

[0119] In step (B) the aqueous crosslinker dispersion may preferably be stirred, in particular using apparatuses known to those skilled in the art, in particular propeller stirrers, anchor stirrers, dissolver disks, 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 crosslinker dispersion (A) using, for example, peristaltic pumps, diaphragm pumps, eccentric screw pumps. 2024PF30060 - Foreign Countries

[0120] - 17 -

[0121] Details and preferred embodiments of the at least one organic dialkyl dicarbonate used in step (B) of the process according to the invention have already been described above and apply correspondingly to the process according to the invention.

[0122] In the treatment in step (B), reaction of the at least one organic dialkyl dicarbonate in water, i.e. hydrolysis with the water of the crosslinker dispersion, releases at least one alcohol. Examples are the release 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 part. The carbon dioxide formed in the reaction of the at least one organic dialkyl dicarbonate in the water, i.e., hydrolysis with the water of the crosslinker dispersion, either remains physically dissolved in the dispersion, reacts with water to form carbonic acid or carbonates, and / or may be removed from the dispersion. Partial or complete removal of the carbon dioxide formed is possible by heating the dispersion or by applying vacuum.

[0123] Before adding the at least one organic dialkyl dicarbonate to the aqueous crosslinker 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 2-butanone, or N-alkyl pyrrolidones such as N- methyl -2 -pyrrolidone, N-ethyl -2 -pyrrolidone or N-butyl -2 -pyrrolidone. Use is preferably made of solvents which do not decompose the organic dialkyl dicarbonate or deactivate its effect. Further additives may also be added to the dialkyl dicarbonate before addition to the aqueous dispersion. In a preferred variant, the dialkyl dicarbonate is added in pure form, i.e. without further premixing or pre-dilution.

[0124] 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 metered addition rate of the at least one organic dialkyl dicarbonate is controlled using a liquid flowmeter unit and a metering unit coupled thereto.

[0125] What is ultimately obtained after step (B) of the process according to the invention as a result of reactions including the hydrolysis of the at least one organic dialkyl dicarbonate is an aqueous crosslinker dispersion which is largely free of the organic dialkyl dicarbonate used. Before it is applied or used, the aqueous crosslinker dispersion obtained preferably no longer contains any organic dialkyl dicarbonate. 2024PF30060 - Foreign Countries

[0126] - 18 -

[0127] According to the invention, it is possible to add at least one compound having a biocidal effect which is distinct from the at least one organic dialkyl dicarbonate before, after or simultaneously with step (B).

[0128] However, it is also possible for the aqueous crosslinker dispersion obtained in step (B) 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.

[0129] According to the invention, it is possible for the aqueous dispersion to be used after step (B) for producing articles, coatings, adhesive layers or adhesives.

[0130] In a preferred embodiment, step (B) is followed by at least the following step (C):

[0131] (C) production of articles, coatings, adhesive layers or adhesives from the aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents obtained in step (B).

[0132] Appropriate processes carried out in step (C) of the process according to the invention are known per se to those skilled in the art, for example,

[0133] • dip coating, in particular for the production of gloves, preferably for use in the medical field,

[0134] • production of aqueous adhesive dispersions that are processed with and without crosslinkers, for example isocyanate or polycarbodiimide crosslinkers,

[0135] • 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,

[0136] • production and / or coating of textiles, leather or synthetic leather and microfibre-based textiles or synthetic leather,

[0137] • use in coatings or adhesives in combination with hydroxy-functional resins

[0138] • use in sizes in the production of carbon fibres, glass fibres or fibres of other mineral materials which are preferably used for producing fibre-reinforced composite materials,

[0139] • coatings on plastics, metallic materials, wood, composite materials, ceramic materials, mineral substrates such as stone,

[0140] • and also on previously coated substrates. 2024PF30060 - Foreign Countries

[0141] - 19 -

[0142] Preferred articles according to the invention are selected for example from articles produced by dip coating, for example disposable gloves or condoms, covers or sleeves for medical devices, probes, endoscopes, coated textiles, bandages, fdms for wound dressings, medical foams or wearable patches.

[0143] Coatings preferred according to the invention are selected for example from primer, fdler, base coat and top coat systems, coatings of wood, metal and plastics, textiles, leather, synthetic leather, each in various industries, for example in cars, large vehicles, ACE (agricultural, construction & earth moving equipment), industrial coatings, furniture or fibreglass sizing.

[0144] Adhesives preferred according to the invention are selected for example from crosslinker dispersion adhesives which are processed as either 1- or 2-component systems, non-reactive and reactive adhesive films, adhesive powders or adhesive layers, in each case applied to substrate surfaces.

[0145] The present invention also relates to an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, which is obtained or is obtainable by the process according to the invention. Details and preferred embodiments of the aqueous crosslinker dispersion and of the organic dialkyl dicarbonate have already been described above and apply correspondingly to the aqueous crosslinker dispersion according to the invention having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, which is obtained or is obtainable by the process according to the invention.

[0146] The present invention also relates to articles, coating, adhesive layer, coating formulation, adhesive formulation and / or medical device formulation containing at least the aqueous crosslinker dispersion according to the invention having a reduced content of thermally eliminable, isocyanate-reactive blocking agents.

[0147] It is preferable to mix the crosslinker dispersion according to the present invention with at least one difunctional, isocyanate-reactive compound, such as any desired polyol component, preferably in the form aqueous dispersions. The present invention is also directed to a one-component system comprising the aqueous dispersion of the present invention and at least one difunctional, isocyanatereactive compound, preferably at least one polyol. Polyol components of this kind may be polyhydroxy polyesters, polyhydroxy polyurethanes, polyhydroxy polyethers, polycarbonate diols or hydroxyl-containing polymers, examples being the conventional polyhydroxy polyacrylates, polyacrylate-polyurethanes and / or polyurethane-polyacrylates. These components generally have a hydroxyl number of 10 to 200, preferably of 50 to 130 mg KOH / g. 2024PF30060 - Foreign Countries

[0148] - 20 -

[0149] Various aspects of the subject matter described herein are set out in the following numbered clauses: Clause 1. Use of at least one organic dialkyl dicarbonate for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent.

[0150] Clause 2. The use of clause 1, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent are at least one pyrazole and / or at least one acetone oxime.

[0151] Clause 3. The use of clause 1 or 2, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent is selected from 3,5-dimethylpyrazole, 2-butanone oxime, acetone oxime, and any mixture of at least two thereof.

[0152] Clause 4. The use of any of clauses 1 to 3, characterized in that the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate is in the range from 0.0001% by weight to 5% by weight, preferably from 0.01% by weight to 1% by weight, most preferred from 0.02% by weight to 0.1% by weight, relative to the total weight of the aqueous crosslinker dispersion as 100% by weight.

[0153] Clause 5. The use of any of clauses 1 to 4, characterized in that the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is reduced by more than 80% by weight, preferably more than 90% by weight, particularly preferably more than 95% by weight, yet more preferably more than 98% by weight, relative to the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate as 100% by weight.

[0154] Clause 6. The use of any of clauses 1 to 5, characterized in that the aqueous crosslinker dispersion contains at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, wherein the at least one compound having a biocidal effect is preferably a bactericide, fungicide and / or algicide, particularly preferably at least one isothiazolinone, yet more preferably is selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two thereof, yet more preferably is selected from the group consisting of 5 -chloro-2-methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof, wherein the at least one compound having a biocidal effect is preferably present in an amount of 1 to 1000 mg / kg relative to the total aqueous crosslinker dispersion.

[0155] Clause 7. The use of any of clauses 1 to 6, 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, 2024PF30060 - Foreign Countries

[0156] - 21 - diisobutyl dicarbonate and / or mixtures of at least two thereof, preferably dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, and particularly preferably is dimethyl dicarbonate.

[0157] Clause 8. The use of any of clauses 1 to 7, characterized in that the at least one crosslinker 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 relative to the total aqueous crosslinker dispersion.

[0158] Clause 9. The use of any of clauses 1 to 8, characterized in that the aqueous crosslinker dispersion contains additional components are present selected from binders, assistants and additives, fdlers, auxiliaries, levelling agents, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0159] Clause 10. The use of any of clauses 1 to 9, characterized in that the at least one crosslinker was obtained or is obtainable by reacting the following synthesis components:

[0160] (a) optionally at least one diol and / or polyol component;

[0161] (b) at least one di- and / or polyisocyanate component;

[0162] (c) at least one thermally eliminable, isocyanate-reactive blocking agent;

[0163] (d) at least one isocyanate-reactive component comprising at least one hydrophilizing group; and

[0164] (e) optionally at least one mono-, di- and / or tri-amino-functional and / or hydroxyaminofunctional compound; and

[0165] (f) optionally other isocyanate-reactive compounds, wherein the components (a), (b), (c), (d), (e) and (f) are distinct.

[0166] Clause 11. The use of any of clauses 1 to 10, characterized in that the at least one crosslinker is a polyurethane, preferably a polyurethane-polyurea.

[0167] Clause 12. The use of any of clauses 1 to 11, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent present in the dispersion comprises thermally eliminable, isocyanate-reactive blocking agent that exists as residual, unreacted material that has not formed covalent chemical bonds with the isocyanate functional groups of the crosslinker, preferably the at least one thermally eliminable, isocyanate-reactive blocking agent present in the dispersion is thermally eliminable, isocyanate-reactive blocking agent that exists as residual, unreacted material that has not formed covalent chemical bonds with the isocyanate functional groups of the crosslinker.

[0168] Clause 13. Process for producing an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, comprising at least the steps of:

[0169] (A) providing an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanatereactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent;

[0170] (B) treating the aqueous crosslinker dispersion from step (A) with at least one organic dialkyl dicarbonate; 2024PF30060 - Foreign Countries

[0171] - 22 - to obtain an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents.

[0172] Clause 14. The process of clause 13, characterized in that, after step (B), at least the following step (C) is carried out:

[0173] (C) production of articles, coatings, adhesive layers or adhesives from the aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents obtained in step (B).

[0174] Clause 15. The process of any of clauses 13 to 14, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking is selected from at least one pyrazole and / or at least one acetone oxime.

[0175] Clause 16. The process of any of clauses 13 to 15, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent is selected from 3,5-dimethylpyrazole, 2-butanone oxime, acetone oxime, and any mixture of at least two thereof.

[0176] Clause 17. The process of any of clauses 13 to 16, characterized in that the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate is in the range from 0.0001% by weight to 5% by weight, preferably from 0.01% by weight to 1% by weight, relative to the total weight of the aqueous crosslinker dispersion as 100% by weight.

[0177] Clause 18. The process of any of clauses 13 to 17, characterized in that the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is reduced by more than 80% by weight, preferably more than 90% by weight, particularly preferably more than 95% by weight, yet more preferably more than 98% by weight, relative to the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate as 100% by weight.

[0178] Clause 19. The process of any of clauses 13 to 18, characterized in that the aqueous crosslinker dispersion contains at least one compound having a biocidal effect which is distinct from the organic dialkyl dicarbonate, wherein the at least one compound having a biocidal effect is preferably a bactericide, fungicide and / or algicide, particularly preferably at least one isothiazolinone, yet more preferably is selected from the group consisting of chloromethylisothiazolinone, methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, butylbenzisothiazolinone, dichlorooctylisothiazolinone and / or mixtures of at least two thereof, yet more preferably is selected from the group consisting of 5 -chloro-2-methylisothiazolinone / 2 -methylisothiazolinone and / or mixtures thereof, wherein the at least one compound having a biocidal effect is preferably present in an amount of 1 to 1000 mg / kg relative to the total aqueous crosslinker dispersion.

[0179] Clause 20. The process of any of clauses 13 to 19, 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 2024PF30060 - Foreign Countries

[0180] - 23 - dicarbonate, diisobutyl dicarbonate and / or mixtures of at least two thereof, preferably dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, and particularly preferably is dimethyl dicarbonate.

[0181] Clause 21. The process of any of clauses 13 to 20, characterized in that the at least one crosslinker 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 relative to the total aqueous crosslinker dispersion.

[0182] Clause 22. The process of any of clauses 13 to 21, characterized in that the aqueous crosslinker dispersion contains additional components are present selected from binders, assistants and additives, fdlers, auxiliaries, levelling agents, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0183] Clause 23. The process of any of clauses 13 to 22, characterized in that the at least one crosslinker was obtained or is obtainable by reacting the following synthesis components:

[0184] (a) optionally at least one diol and / or polyol component;

[0185] (b) at least one di- and / or polyisocyanate component;

[0186] (c) at least one thermally eliminable, isocyanate-reactive blocking agent;

[0187] (d) at least one isocyanate-reactive component comprising at least one hydrophilizing group; and

[0188] (e) optionally at least one mono-, di- and / or tri-amino-functional and / or hydroxyaminofunctional compound; and

[0189] (f) optionally other isocyanate-reactive compounds, wherein the components (a), (b), (c), (d), (e) and (f) are distinct.

[0190] Clause 24. The process of any of clauses 13 to 23, 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 from 0.1 g / kg to 20 g / kg, relative to the total aqueous crosslinker dispersion.

[0191] Clause 25. The process of any of clauses 13 to 24, characterized in that the at least one crosslinker is a polyurethane, preferably a polyurethane-polyurea.

[0192] Clause 26. The process of any of clauses 13 to 25, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent present in the dispersion comprises thermally eliminable, isocyanate-reactive blocking agent that exists as residual, unreacted material that has not formed covalent chemical bonds with the isocyanate functional groups of the crosslinker, preferably the at least one thermally eliminable, isocyanate-reactive blocking agent present in the dispersion is thermally eliminable, isocyanate-reactive blocking agent that exists as residual, unreacted material that has not formed covalent chemical bonds with the isocyanate functional groups of the crosslinker. Clause 27. Use according to any of clauses 1 to 12, characterized in that the at least one organic dialkyl dicarbonate is used in a process according to any of clauses 13 to 26 for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion. 2024PF30060 - Foreign Countries

[0193] - 24 -

[0194] Clause 28. Aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, which is obtained or is obtainable by the process according to any of clauses 13 to 27.

[0195] Clause 29. Aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one reaction product of a thermally eliminable, isocyanate-reactive blocking agent with an organic dialkyl dicarbonate.

[0196] Clause 30. Aqueous crosslinker dispersion according to clause 29, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent are at least one pyrazole and / or at least one acetone oxime.

[0197] Clause 31. Aqueous crosslinker dispersion according to clause 29 or 30, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent is selected from 3,5- dimethylpyrazole, 2-butanone oxime, acetone oxime, and any mixture of at least two thereof.

[0198] Clause 32. Aqueous crosslinker dispersion according to any of clauses 29 to 31, characterized in that the at least one reaction product (2) is an alkyl oxy carbonyl derivative of a thermally eliminable, isocyanate-reactive blocking agent.

[0199] Clause 33. Aqueous crosslinker dispersion according to any of clauses 29 to 32, 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, diisobutyl dicarbonate and / or mixtures of at least two thereof, preferably dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, and particularly preferably is dimethyl dicarbonate.

[0200] Clause 34. Aqueous crosslinker dispersion according to any of clauses 29 to 33, characterized in that the at least one crosslinker 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 relative to the total aqueous crosslinker dispersion.

[0201] Clause 35. Aqueous crosslinker dispersion according to any of clauses 29 to 34, characterized in that the aqueous crosslinker dispersion contains additional components are present selected from binders, assistants and additives, fdlers, auxiliaries, levelling agents, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

[0202] Clause 36. Aqueous crosslinker dispersion according to any of clauses 29 to 35, characterized in that the at least one crosslinker was obtained or is obtainable by reacting the following synthesis components:

[0203] (a) optionally at least one diol and / or polyol component;

[0204] (b) at least one di- and / or polyisocyanate component;

[0205] (c) at least one thermally eliminable, isocyanate-reactive blocking agent; 2024PF30060 - Foreign Countries

[0206] - 25 -

[0207] (d) at least one isocyanate-reactive component comprising at least one hydrophilizing group; and

[0208] (e) optionally at least one mono-, di- and / or tri-amino-functional and / or hydroxyaminofunctional compound; and

[0209] (f) optionally other isocyanate-reactive compounds, wherein the components (a), (b), (c), (d), (e) and (f) are distinct.

[0210] Clause 37. Aqueous crosslinker dispersion according to any of clauses 29 to 36, characterized in that the at least one crosslinker is a polyurethane, preferably a polyurethane-polyurea.

[0211] Clause 38. Aqueous crosslinker dispersion according to any of clauses 29 to 37, characterized in that the at least one reaction product (2) is selected from the group consisting of

[0212] 2-butanone, O-(ethoxycarbonyl)oxime (i.e, reaction product of 2-butanone oxime with diethyl dicarbonate);

[0213] 2-butanone, O-(methoxycarbonyl)oxime (i.e., reaction product of 2-butanone oxime with dimethyl dicarbonate);

[0214] I / / -Pyrazolc- 1 -carboxylic acid, 3,5-dimethyl-, methyl ester (i.e., reaction product of 3,5- dimethylpyrazole with dimethyl dicarbonate);

[0215] I / / -Pyrazolc- 1 -carboxylic acid, 3,5-dimethyl-, ethyl ester (i.e., reaction product of 3,5- dimethylpyrazole with diethyl dicarbonate); and any mixture of at least two thereof.

[0216] Clause 39. Aqueous crosslinker dispersion according to any of clauses 29 to 38, characterized in that the at least one reaction product (2) is present in the aqueous crosslinker dispersion in an amount of from 0.0001% by weight to 5% by weight, preferably from 0.01% by weight to 1% by weight, relative to the total weight of the aqueous crosslinker dispersion as 100% by weight.

[0217] Clause 40. One-component system comprising the aqueous crosslinker dispersion of any of clauses 28 to 39 and at least one difunctional, isocyanate-reactive compound, preferably at least one polyol.

[0218] Clause 41. One-component system according to clause 40, wherein the at least one polyol has a hydroxyl number of 10 to 200 mg KOH / g, preferably of 50 to 130 mg KOH / g.

[0219] Clause 42. Article, coating, adhesive layer, coating formulation and / or adhesive formulation obtained by curing the aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents according to clause 28 or obtained by curing the aqueous crosslinker dispersion according to any of clauses 29 to 39.

[0220] The present invention will now be elucidated using examples. 2024PF30060 - Foreign Countries

[0221] - 26 -

[0222] Experimental

[0223] Materials and sources

[0224] The polyurethane dispersions used (Baybond® PU 406, Dispercoll® U 54) were obtained from Covestro Deutschland AG, Leverkusen, DE.

[0225] All other chemicals were obtained from Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany, unless otherwise stated.

[0226] DMDC: Dimethyl dicarbonate

[0227] DEDC: Diethyl dicarbonate

[0228] Butanone oxime

[0229] 3,5-Dimethylpyrazole, Lonza AG, Basel, CH

[0230] CMIT: Chloromethylisothiazolinone (5-chloro-2-methylisothiazolinone)

[0231] MIT: Methylisothiazolinone (2-methylisothiazolinone)

[0232] 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

[0233] Unless otherwise stated, all percentages are percentages by weight (% by weight).

[0234] Unless otherwise stated, all procedures and analytical measurements were performed at a temperature of 23°C (room temperature).

[0235] Methods:

[0236] Method for determining the free, i.e., not chemically reacted, butanone oxime and 3,5- dimethylpyrazole :

[0237] The concentrations of free, i.e. not chemically reacted, butanone oxime and 3,5-dimethylpyrazole is determined by means of high-performance liquid chromatography with mass spectrometry coupling (HPLC-MS) using reversed phase columns (RP columns) with water as running medium. Detection is carried out via electrospray ionisation in positive mode (ESI+). 2024PF30060 - Foreign Countries

[0238] - 27 -

[0239] Examples:

[0240] Experiment 1

[0241] A sample of the polyurethane dispersion Baybond® PU 406 (non-ionic hydrophilic PU dispersion with polyether backbone, Covestro Deutschland AG, Leverkusen, Germany) was mixed with approx. 100 ppm butanone oxime (based on the original dispersion) while stirring at room temperature and left to stand overnight. The mixture was then divided into 4 parts of 50 g each. The samples were stirred in a vessel with a magnetic stirrer and the following was added: a) Nothing (reference) b) 0.05 g dimethyl dicarbonate c) 0.25 g dimethyl dicarbonate d) 0.5 g dimethyl dicarbonate

[0242] Stirring was carried out for 4 hours at room temperature. After a further day at room temperature, approx. 24 hours after addition of the additives, the butanone oxime content was analysed.

[0243] Table 1: Results of analysis of experiment 1 [a) is a reference example not in accordance with the invention]

[0244] Evaluation: Dimethyl dicarbonate as an additive led to a significant reduction in the content of butanone oxime in the sample. 2024PF30060 - Foreign Countries

[0245] - 28 -

[0246] Experiment 2

[0247] A sample of the polyurethane dispersion Baybond® PU 406 (non-ionic hydrophilic PU dispersion with polyether backbone, Covestro Deutschland AG, Leverkusen, Germany) was mixed with approx. 1000 ppm butanone oxime (based on the original dispersion) while stirring at room temperature and left to stand overnight. The mixture was then divided into 4 parts of 50 g each. The samples were stirred in a vessel with a magnetic stirrer and the following was added: a) Nothing (reference) b) 0.05 g dimethyl dicarbonate c) 0.25 g dimethyl dicarbonate d) 0.5 g dimethyl dicarbonate

[0248] Stirring was carried out for 4 hours at room temperature. After a further day at room temperature, approx. 24 hours after addition of the additives, the butanone oxime content was analysed.

[0249] Table 2: Results of analysis of experiment 2

[0250] [a) is a reference example not in accordance with the invention]

[0251] Evaluation: Dimethyl dicarbonate as an additive led to a significant reduction in the content of butanone oxime in the sample.

[0252] Experiment 3

[0253] A sample of the polyurethane dispersion Baybond® PU 406 (non-ionic hydrophilic PU dispersion with polyether backbone, Covestro Deutschland AG, Leverkusen, Germany) was mixed with approx. 100 ppm 3,5-dimethylpyrazole (based on the original dispersion) while stirring at room temperature and left to stand overnight. The mixture was then divided into 4 parts of 50 g each. The samples were stirred in a vessel with a magnetic stirrer and the following was added: a) Nothing (reference) b) 0.05 g dimethyl dicarbonate c) 0.25 g dimethyl dicarbonate d) 0.5 g dimethyl dicarbonate 2024PF30060 - Foreign Countries

[0254] - 29 -

[0255] Stirring was carried out for 4 hours at room temperature. After a further day at room temperature, approx. 24 hours after addition of the additives, the 3,5-dimethylpyrazole content was analysed.

[0256] Table 3: Results of analysis of experiment 3

[0257] [a) is a reference example not in accordance with the invention] Evaluation: Dimethyl dicarbonate as an additive led to a significant reduction in the content of 3,5- dimethylpyrazole in the sample.

[0258] Experiment 4

[0259] A sample of the polyurethane dispersion Baybond® PU 406 (non-ionically hydrophilized PU dispersion with polyether backbone, Covestro Deutschland AG, Leverkusen, Germany) was mixed with approx. 1000 ppm of 3,5-dimethylpyrazole (relative to the original dispersion) while stirring at room temperature and left to stand overnight. The mixture was then divided into 4 parts of 50 g each. The samples were stirred in a container with a magnetic stirrer and the following was added: a) Nothing (reference) b) 0.05 g dimethyl dicarbonate c) 0.25 g dimethyl dicarbonate d) 0.5 g dimethyl dicarbonate

[0260] Stirring was carried out for 4 hours at room temperature. After a further day at room temperature, approx. 24 hours after addition of the additives, the 3,5-dimethylpyrazole content was analysed.

[0261] 2024PF30060 - Foreign Countries

[0262] - 30 -

[0263] Table 4: Results of analysis of experiment 4

[0264] [a) is a reference example not in accordance with the invention]

[0265] Evaluation: Dimethyl dicarbonate as an additive led to a significant reduction in the content of 3,5- Dimethylpyrazole in the sample. Experiment 5

[0266] A sample of the polyurethane dispersion Baybond® PU 406 (non-ionically hydrophilized PU dispersion with polyether backbone, Covestro Deutschland AG, Leverkusen, Germany) was mixed with approx. 1000 ppm of 3,5-dimethylpyrazole (relative to the original dispersion) while stirring at room temperature and left to stand overnight. The mixture was then divided into 3 parts of 50 g each. The samples were stirred in a container with a magnetic stirrer and the following was added: a) Nothing (reference) b) 0.075 g diethyl dicarbonate c) 0.375 g diethyl dicarbonate

[0267] Stirring was carried out for 4 hours at room temperature. After a further day at room temperature, approx. 24 hours after addition of the additives, the 3,5-dimethylpyrazole content was analysed.

[0268] Table 5: Results of analysis of experiment 5

[0269] [a) is a reference example not in accordance with the invention] 2024PF30060 - Foreign Countries

[0270] - 31 -

[0271] Evaluation: Diethyl dicarbonate as an additive led to a significant reduction in the content of 3,5- Dimethylpyrazole in the sample.

[0272] Experiment 6

[0273] A sample of the polyurethane dispersion Baybond® PU 406 (non-ionically hydrophilized PU dispersion with polyether backbone, Covestro Deutschland AG, Leverkusen, Germany) was mixed with approx. 1000 ppm butanone oxime (relative to the original dispersion) while stirring at room temperature and left to stand overnight. The mixture was then divided into 4 parts of 50 g each. The samples were stirred in a container with a magnetic stirrer and the following was added: a) Nothing (reference) b) 0.075 g diethyl dicarbonate c) 0.375 g diethyl dicarbonate

[0274] Stirring was carried out for 4 hours at room temperature. After a further day at room temperature, approx. 24 hours after addition of the additives, the 3,5-dimethylpyrazole content was analysed.

[0275] Table 6: Results of analysis of experiment 6

[0276] [a) is a reference example not in accordance with the invention]

[0277] Evaluation: Diethyl dicarbonate as an additive led to a significant reduction in the content of butanone oxime in the sample.

[0278] There were no noticeable changes to the polyurethane dispersions during and after the addition of the additives dimethyl dicarbonate and diethyl dicarbonate. Average particle size (measured by a Zetasizer, Malvern Panalytical Ltd, UK) and dispersion viscosity (Haake Viscotester iQ, Fisher Scientific GmbH, Schwerte, DE) did not change significantly, but rather only within the range of typical variations of the analytical methods. Films of the dispersions were mounted on glass plates (squeegee 210 m gap width and dried at 50°C for 1 hour and then at 120°C for 1 hour). There were no visually discernible differences in the flow, film quality or colour of the films after the addition of the additive dimethyl dicarbonate and diethyl dicarbonate compared to the films without the additive. 2024PF30060 - Foreign Countries

[0279] - 32 -

[0280] Experiment 7

[0281] Compatibility of organic dicarbonates with biocidal active ingredients.

[0282] 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.

[0283] 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. Table 5: Results of analysis of experiment 7

[0284] Evaluation: No detectable decomposition of the active ingredients chloromethylisothiazolinone and methylisothiazolinone through addition of dimethyl dicarbonate was observed.

Claims

2024PF30060 - Foreign Countries- 33 -Claims1. Use of at least one organic dialkyl dicarbonate for reducing the content of thermally eliminable, isocyanate-reactive blocking agents in an aqueous crosslinker dispersion comprising(1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and(2) at least one thermally eliminable, isocyanate-reactive blocking agent.

2. The use according to claim 1, characterized in that the at least one thermally eliminable, isocyanate-reactive blocking agent are at least one pyrazole, preferably 3,5-dimethylpyrazole, and / or at least one oxime, preferably 2-butanone oxime and / or acetone oxime.

3. The use according to any of claims 1 to 2, 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, diisobutyl dicarbonate and / or mixtures of at least two thereof, preferably dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, and particularly preferably is dimethyl dicarbonate.

4. The use according to any of claims 1 to 3, characterized in that the at least one crosslinker is a polyurethane, preferably a polyurethane-polyurea.

5. Process for producing an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents, comprising at least the steps of:(A) providing an aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one thermally eliminable, isocyanate-reactive blocking agent;(B) treating the aqueous crosslinker dispersion from step (A) with at least one organic dialkyl dicarbonate; to obtain an aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanate-reactive blocking agents.

6. The process according to claim 5, characterized in that, after step (B), at least the following step (C) is carried out:(C) production of articles, coatings, adhesive layers or adhesives from the aqueous crosslinker dispersion having a reduced content of thermally eliminable, isocyanatereactive blocking agents obtained in step (B).2024PF30060 - Foreign Countries- 34 -7. The process according to any of claims 5 to 6. characterized in that the thermally eliminable, isocyanate-reactive blocking agent are pyrazoles, preferably 3,5-dimethylpyrazole, and / or oximes, preferably 2-butanone oxime and / or acetone oxime.

8. The process according to any of claims 5 to 7, characterized in that the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion 24 hours after the addition or use of the at least one organic dialkyl dicarbonate is reduced by more than 80% by weight, preferably more than 90% by weight, particularly preferably more than 95% by weight, yet more preferably more than 98% by weight, relative to the content of thermally eliminable, isocyanate-reactive blocking agents in the aqueous crosslinker dispersion before the addition or use of the at least one organic dialkyl dicarbonate as 100% by weight.

9. The process according to any of claims 5 to 8, 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, diisobutyl dicarbonate and / or mixtures of at least two thereof, preferably dimethyl dicarbonate, diethyl dicarbonate and / or a mixture thereof, and particularly preferably is dimethyl dicarbonate.

10. The process according to any of claims 5 to 9, characterized in that the at least one crosslinker 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 relative to the total aqueous crosslinker dispersion.

11. The process according to any of claims 5 to 10, characterized in that the at least one crosslinker was obtained or is obtainable by reacting the following synthesis components:(a) optionally at least one diol and / or polyol component;(b) at least one di- and / or polyisocyanate component;(c) at least one thermally eliminable, isocyanate-reactive blocking agent;(d) at least one isocyanate-reactive component comprising at least one hydrophilizing group; and(e) optionally at least one mono-, di- and / or tri-amino-fimctional and / or hydroxyaminofunctional compound; and(f) optionally other isocyanate-reactive compounds, wherein the components (a), (b), (c), (d), (e) and (f) are distinct.

12. The process according to any of claims 5 to 11, characterized in that the at least one crosslinker is a polyurethane, preferably a polyurethane-polyurea.2024PF30060 - Foreign Countries- 35 -13. Aqueous crosslinker dispersion comprising (1) at least one crosslinker comprising isocyanate groups blocked with at least one thermally eliminable, isocyanate-reactive blocking agent, and (2) at least one reaction product of a thermally eliminable, isocyanate-reactive blocking agent with an organic dialkyl dicarbonate.

14. Aqueous crosslinker dispersion according to claim 13, characterized in that the at least one reaction product (2) is an alkyl oxy carbonyl derivative of a thermally eliminable, isocyanatereactive blocking agent.

15. Aqueous crosslinker dispersion according to claim 13 or 14, characterized in that the at least one reaction product (2) is selected from the group consisting of2-butanone, O-(ethoxycarbonyl)oxime (i.e, reaction product of 2-butanone oxime with diethyl dicarbonate);2-butanone, O-(methoxycarbonyl)oxime (i.e., reaction product of 2-butanone oxime with dimethyl dicarbonate);I H-Pyrazolc- 1 -carboxylic acid, 3,5-dimethyl-, methyl ester (i.e., reaction product of 3,5- dimethylpyrazole with dimethyl dicarbonate);I H-Pyrazolc- 1 -carboxylic acid, 3,5-dimethyl-, ethyl ester (i.e., reaction product of 3,5- dimethylpyrazole with diethyl dicarbonate); and any mixture of at least two thereof.

16. One-component system comprising the aqueous dispersion of any of claims 13 to 15 and at least one difunctional, isocyanate-reactive compound, preferably at least one polyol.

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