Water-based polyurethane dispersion

Abstract

The present invention relates to an aqueous polyurethane dispersion comprising a polyurethane A having pendant acid salt groups and terminal carbonyl groups, and optionally a multifunctional compound B having a functional group capable of reacting with the carbonyl group of polyurethane A. The present invention further relates to a method for producing said aqueous polyurethane dispersion, and to a coating comprising said aqueous polyurethane dispersion.

Description

[Technical field]

[0001] The present invention relates to aqueous polyurethane dispersions of polyurethanes containing carbonyl groups and, optionally, polyfunctional compounds having functional groups capable of reacting with the polyurethane carbonyl groups. The present invention also relates to methods for preparing said aqueous dispersions and to aqueous coating formulations prepared from said dispersions for application to and curing on a wide range of substrates. [Background technology]

[0002] Water-based polyurethanes are known in the art.

[0003] WO 2006086322 and U.S. Patent Application Publication No. 2006264568 disclose a) a urethane polymer having a number average molecular weight of at least 2000 Daltons; b) a ketone-functional molecule having a number average molecular weight of less than 2000 Daltons having at least one ketone-functional moiety; c) at least one molecule of a number average molecule less than 2000 daltons having at least one hydrazine moiety co-reactive with said ketone functional moiety; and d) water Disclosed is an aqueous dispersion of a polyurethane comprising: In the case of urethane polymers containing ketone-functional moieties, the ketone-functional moieties are incorporated into the polyurethane by reaction of a diisocyanate with the reaction product of levulinic acid and the diglycidyl ether of bisphenol A, thus referring to a polyurethane containing pendant ketone functionality.

[0004] EP 332326 discloses an aqueous self-crosslinking coating composition comprising an aqueous dispersion comprising at least one polyurethane polymer, said composition having hydrazine (or hydrazone) functional groups and carbonyl functional groups present in the composition to provide a self-crosslinking reaction, said at least one polyurethane polymer participating via azomethine formation from reaction of the hydrazine (or hydrazone) functional groups and the carbonyl functional groups during and / or after film formation from the aqueous composition.

[0005] U.S. Pat. No. 5,147,926 states: A) has a carbonyl group and is dispersed in water in the presence of ammonia or an organic amine; a) an organic polyisocyanate; b) compounds containing one or more active hydrogen atoms and one or more bases or one or more groups capable of salt formation, and c) polyurethanes obtained by reaction of carbonyl-containing mono- and / or polyalcohols selected from hydroxyacetone, hydroxybenzaldehyde, acetoin, benzoin or mixtures; B) a polyhydrazide; Disclosed is a shelf-stable crosslinkable aqueous polyurethane dispersion comprising: In US Patent No. 5,147,926, suitable carbonyl-containing mono- and / or polyalcohols c) are described, for example, hydroxyacetone, hydroxybenzaldehyde, acetoin and benzoin. Adducts of diepoxides, such as 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), and ketocarboxylic acids, such as pyruvic acid and levulinic acid, are also described as suitable. Other suitable components c) described are ketocarboxylates, which can be obtained by partial esterification of ketocarboxylic acids with polyalcohols or by partial transesterification of ketocarboxylates with polyalcohols (partial esters). These esters also have one or more, preferably two, hydroxyl groups.

[0006] DE 19647982 A1 discloses aqueous dispersions containing polyurethane polymers having structural units containing keto and amide groups. For example, N-(2-hydroxyethyl)acetoacetamide can be prepared in MEK by the following procedure: a) a polyester polyol consisting of adipic acid, isophthalic acid and 1,6-hexanediol; b) dimethylolpropionic acid, c) 1,4-butanediol, and d) Isophorone diisocyanate It is described to react with The polyurethane prepolymer so formed was neutralized with triethylamine and dispersed in water, and then diethyl ether amine was added to the dispersion. After removing the process solvent, the dispersion had a solids content of 34.9% and a pH value of 7.6.

[0007] Object of the invention The present invention aims to provide an aqueous dispersion for a coating composition that does not exhibit the limitations of the prior art.

[0008] It is an object of the present invention to provide an aqueous polyurethane dispersion having improved solubility and redissolution properties compared to state of the art systems.

[0009] It is a further object of the present invention to provide an aqueous polyurethane dispersion for use in coating formulations that are part of a multi-layer system having improved intercoat adhesion. Summary of the Invention

[0010] The present invention relates to - polyurethane A having pendant acid groups and terminal carbonyl groups, and optionally a polyfunctional compound B having functional groups capable of reacting with the carbonyl groups of the polyurethane A The present invention discloses an aqueous polyurethane dispersion comprising: Where: Said polyurethane A, in its solid, non-neutralized form, a weight average molecular weight comprised between 3,000 and 30,000 g / mol, as measured by GPC in tetrahydrofuran calibrated with polystyrene standards; - characterized by a carbonyl content of more than 150 mmol / kg, The polyurethane A is an isocyanate-functional polyurethane prepolymer A1 containing acid groups, and - 50 to 100 moles of carbonyl-functional building blocks A2 per 100 isocyanate equivalents of the isocyanate-functional polyurethane prepolymer A1, said carbonyl-functional building blocks A2 being reaction products of α,β ethylenically unsaturated groups containing compounds containing a carbonyl group A21 and a primary amine A22, said primary amine A22 being selected from the group consisting of alkylamines, alkanolamines and mixtures thereof, and - from 0 to 50 moles of a primary amine A22, per 100 isocyanate equivalents of the isocyanate-functional polyurethane prepolymer A1, said primary amine A22 being selected from the group consisting of alkylamines, alkanolamines and mixtures thereof, and - one or more acid neutralizing compounds N is the reaction product with Where: said carbonyl functional component A2 has the formula R 1 -NH-R 2 (In the formula, R 1 is an alkyl or hydroxyalkyl moiety, and R 2 is a molecular entity containing a carbonyl group), said carbonyl-functional building blocks A2 are linked to the isocyanate-functional polyurethane prepolymer A1 by urea bonds, The carbonyl-functional building blocks A2 are attached to the ends of the isocyanate-functional polyurethane prepolymer A1.

[0011] Preferred embodiments of the present invention disclose one or more of the following features. Polyurethane A, in its solid non-neutralized form, -0 mmol / kg hydroxyl content (R 1 is an alkyl group and an optional additional alkylamine, or - Hydroxyl content (R 1 is a hydroxyalkyl group and an optional additional alkanolamine, or Hydroxyl content (R) between -0 mmol / kg and at least 250 mmol / kg 1 is a mixture of alkyl and hydroxyalkyl groups, and optionally additional alkylamines, alkanolamines, or mixtures thereof. The carbonyl groups of the carbonyl functional building block A2 are of the ketone and / or aldehyde type. The carbonyl functional building block A2 is - α,β ethylenically unsaturated groups, including compounds containing a carbonyl group A21, the α,β ethylenically unsaturated groups being vinyl alkyl ketones having 4 to 7 carbon atoms, such as acrolein, methacrolein, diacetone acrylamide, crotonaldehyde, 4-vinylbenzaldehyde, vinyl methyl ketone, and the like, as well as compounds of the formula CH2=CHR 3 -C=OO-CHR 4 -CR 5 R 6 -C=OH acryloxy- and methacryloxy-alkylpropanols, 3 is H or methyl, and R 4 is H or alkyl of 1 to 3 carbon atoms, R 5 is alkyl of 1 to 3 carbon atoms, R 6 is an alkyl group of 1 to 4 carbon atoms; - Primary amines A22 selected from the group consisting of C1-C6 alkylamines, C1-C6 alkanolamines and mixtures thereof It is a Michael addition reaction product of The carbonyl functional building block A2 is primary amines A22 of the formula HO-(CH2)n-NH2 and / or H-(CH2)n-NH2, where n is an integer from 1 to 6, and -Diacetone acrylamide A21 It is a Michael addition reaction product of The isocyanate-functional polyurethane prepolymer A1 is one or more polyisocyanates I, one or more isocyanate-reactive compounds IC having at least two isocyanate-reactive groups selected from the group consisting of monomeric compounds ICM, polymeric compounds ICP and mixtures thereof, and one or more isocyanate-reactive monomers ICMA having at least two isocyanate-reactive groups and at least one acid group or group capable of forming an acid when in contact with water; is the reaction product of Here, the isocyanate groups of I are in stoichiometric excess over the isocyanate-reactive groups of IC and ICMA. - the (optional) polyfunctional compound B contains at least two hydrazide functional groups. - the (optional) polyfunctional compound B is selected from the group consisting of oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, cyclohexanedicarboxylic acid dihydrazide, azelaic acid dihydrazide and sebacic acid dihydrazide. The molar ratio of the carbonyl functional groups of the polyurethane A to the functional groups of the polyfunctional compound B is 0.7 to 1.3.

[0012] The present invention further provides a method for preparing an aqueous polyurethane dispersion, comprising the steps of: a. mixing one or more polymeric compounds ICP having at least two isocyanate-reactive groups with one or more monomers ICM having at least two isocyanate-reactive groups in the presence of one or more isocyanate-reactive monomers ICMA having at least two isocyanate-reactive groups and an acid group or a group capable of forming an acid when contacted with water, and heating the mixture under stirring at a temperature of at least 60° C. for at least 10 minutes; b. continuously adding substoichiometric amounts of one or more polyfunctional isocyanates I to the mixture of step a) over a period of 10 minutes to 80 minutes while maintaining the temperature in the range of 60° C. to 150° C. to form a hydroxyl-functional polyurethane prepolymer; c. maintaining the reaction product of step b) at a temperature comprised between 120 and 135°C for 30 to 90 minutes, followed by cooling to a temperature comprised between 60 and 100°C; d. adding a stoichiometric excess of one or more polyfunctional isocyanates I at once to the hydroxyl-functional polyurethane prepolymer of step c) with stirring at a temperature between 60° C. and 130° C., optionally in the presence of one or more compounds ICM and ICMA, and continuing the reaction at a temperature between 70° C. and 150° C. for at least 1 hour to form an isocyanate-functional polyurethane prepolymer A1 having an isocyanate value corresponding to the theoretical value of 1; e. adding a mixture of compound A2, optionally one or more primary amines A22 and optionally water to the isocyanate-functional polyurethane prepolymer A1 of step d) at rest at a temperature comprised between 70 and 95° C., and homogenizing for at least 10 minutes at the temperature obtained to convert the isocyanate-functional polyurethane prepolymer A1 into a polyurethane containing terminal carbonyl groups; f. adding one or more neutralizing agents N at a time to the polyurethane of step e) containing acid groups and carbonyl groups in water and homogenizing for at least 10 minutes to convert the acid groups to their corresponding salts to obtain polyurethane A containing pendant acid groups and terminal carbonyl groups; g. adding deionized water preheated at a temperature comprised between 50 and 70° C. continuously to the polyurethane A of step f) under vigorous stirring for at least 10 minutes and homogenizing at a temperature comprised between 50 and 70° C. for at least another 20 minutes to form an aqueous dispersion of polyurethane A; h. cooling the aqueous dispersion of polyurethane A of step g) to a temperature below 40° C. and optionally adding a multifunctional compound B; i. adding deionized water to the aqueous dispersion of step h) comprising polyurethane A and optionally polyfunctional compound B to adjust the solids content to 40+ / -1% (by weight); A method is disclosed that includes:

[0013] Preferred embodiments of the method of the present invention exhibit one or more of the following features: the carbonyl-functional building block A2 added in step e) is heating A21 under nitrogen at a temperature comprised between 50 and 80°C until completely melted; adding a molar excess of 1 to 45 percent of A22 at once; heating the mixture of A21 and A22 at a temperature comprised between 60° C. and 85° C. for a time comprised between 1 h and 24 h until complete conversion of the ethylenically unsaturated bonds, as confirmed by Fourier transform infrared spectroscopy; It is prepared by - the one or more neutralizing agents N added in step f) are selected from the group consisting of primary, secondary and tertiary amines and strong Arrhenius bases, such as hydroxides of alkali metals and alkaline earth alkali metals.

[0014] The present invention further discloses a coating composition comprising an aqueous polyurethane dispersion and one or more additives selected from the group consisting of organic solvents, defoamers, coalescing agents, flow control agents, rheology additives, fillers, pigments, active pigments, dyes, wetting agents, emulsifiers, surfactants, thickeners, heat stabilizers, leveling agents, anti-crush agents, anti-settling agents, UV absorbers, and antioxidants.

[0015] Preferred embodiments of the coating compositions of the present invention provide for self-crosslinking reaction by azomethine formation during and / or after film formation.

[0016] The present invention further discloses the use of a coating composition comprising the aqueous polyurethane dispersion for coating a substrate selected from the group consisting of wood, engineered wood, metal, glass, fabric, composites, concrete, ceramic, leather, paper, plastics and foams. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] - polyurethane A having pendant acid groups and terminal carbonyl groups, and optionally a polyfunctional compound B having functional groups capable of reacting with the carbonyl groups of the polyurethane A An aqueous polyurethane dispersion comprising It has been found to result in coating compositions with improved solubility and resolubility.

[0018] Preferably, the aqueous polyurethane dispersion comprises a polyurethane A having pendant acid salt groups and terminal carbonyl groups, and a multifunctional compound B having functional groups capable of reacting with the carbonyl groups of polyurethane A.

[0019] The polyurethanes A of the present invention are the reaction products of an isocyanate-functional polyurethane prepolymer A1 with a carbonyl-functional component A2 or with a mixture comprising an isocyanate-functional polyurethane prepolymer A1 and one or more primary amines A22, the carbonyl-functional component A2 being of the formula R 1 -NH-R 2 (In the formula, R 1 is an alkyl or hydroxyalkyl moiety, and R 2 is a molecular entity that contains a carbonyl group) contains a secondary amine group.

[0020] The isocyanate-functional polyurethane prepolymer A1 is the reaction product of a stoichiometric excess of one or more polyisocyanates I relative to the sum of the isocyanate-reactive compounds IC.

[0021] The isocyanate-reactive compound IC used in the present invention preferably comprises at least two isocyanate-reactive groups and is selected from monomeric compounds ICM having at least two isocyanate-reactive groups, polymeric compounds ICP having at least two isocyanate-reactive groups, and monomeric compounds ICMA having at least two isocyanate-reactive groups and at least one acid group or acid group precursor, and mixtures thereof.

[0022] The one or more polyisocyanates I are selected from the group consisting of aromatic or aliphatic or mixed aliphatic-aromatic isocyanates, preferably trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), propylene diisocyanate, ethyl ethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1-methyltrimethylene diisocyanate, cyclopentylene 1,3-diisocyanate, cyclohexylene 1,4-diisocyanate, cyclohexylene 1,2-diisocyanate, phenylene 1,3-diisocyanate, phenylene 1,4-diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, biphenylene 4,4'-diisocyanate, bis-(4-isocyanate), tert-butyl diisocyanate, ... isocyanatophenyl)methane (MDI), naphthylene 1,5-diisocyanate, naphthylene 1,4-diisocyanate, 1-isocyanatomethyl-5-isocyanato-1,3,3-trimethylcyclohexane (IPDI), bis-(4-isocyanatocyclohexyl)methane (H12-MDI), 4,4'-diisocyanatodiphenyl ether, 2,3-bis-(8-isocyanatooctyl)-4-octyl-5-hexylcyclohexene, trimethylhexamethylene diisocyanate, 1,3-bis(2-isocyanatopropan-2-yl)benzene, meta-tetramethylxylylene diisocyanate (TMXDI), uretdiones of the above diisocyanates, isocyanurates of the above diisocyanates and allophanates of the above diisocyanates and mixtures thereof.

[0023] Preferably, the one or more polyisocyanates are selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-bis(2-isocyanatopropan-2-yl)benzene, and mixtures thereof.

[0024] The one or more polyisocyanates I can be derived from petrochemical feedstocks.

[0025] Alternatively and preferably, where possible, the polyisocyanate I is obtained from renewable feedstocks. Particularly preferred is isophorone diisocyanate obtained from bio-based acetone. Other preferred polyisocyanates partially derived from renewable feedstocks are, for example, 1,5-pentamethylene diisocyanate, diisocyanates of the methyl or ethyl ester of l-lysine, isosorbide-based diisocyanates, furan-based diisocyanates, bis(4-isocyanato-2-methoxyphenoxy)alkanes, bis(4-isocyanato-2,6-dimethoxyphenoxy)alkanes, 2,4-diisocyanato-1-pentadecylbenzene, di- and polyisocyanates based on fatty acids, dimer fatty acids and vegetable oils, 1-isocyanato-10-[(isocyanatomethyl)thio]decane and the product known under the trade name TOLONATE®X FLO 100.

[0026] In yet another alternative, the one or more polyisocyanates I are derived from petrochemical and / or renewable feedstocks.

[0027] In the context of this specification, "renewable feedstock" refers to a natural resource that replenishes, either by natural renewal or other repetitive processes (within a finite period on the human time scale) to replace portions depleted by use and consumption. A substance or mixture of substances derived from such renewable feedstocks should have a bio-based carbon content totaling more than 20% by weight of the total carbon content of the substance or mixture, where the bio-based carbon content is determined using the ASTM D6866-20 standard.

[0028] The monomeric compound ICM having at least two isocyanate-reactive groups is preferably a monomeric compound having at least two hydroxyl groups, or having at least two primary amino groups, or having at least one hydroxyl group and at least one primary amino group.

[0029] The monomeric compound ICM having at least two isocyanate reactive groups can be obtained from petrochemical feedstocks.

[0030] Preferably, the monomeric compound ICM having at least two hydroxyl groups is selected from the group consisting of 1,2-ethanediol, 1,2- and 1,3-propanediol, 1,2- and 1,4-butanediol, 2,2'-oxydi(ethan-1-ol), 2,2-dimethyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,4-bis-hydroxymethylcyclohexane, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,18-octadecanediol, 1,21-heneicosanediol, 1,25-pentacosanediol, isosorbide, isomannide, isoidide and mixtures thereof.

[0031] Alternatively and preferably, where possible, said monomeric compounds ICM having at least two hydroxyl groups (eg, 1,3-propanediol, isosorbide, isomannide, isoidide) are obtained from renewable feedstocks.

[0032] In yet another alternative, said monomeric compound ICM having at least two hydroxyl groups is derived from a petrochemical and / or renewable feedstock.

[0033] Preferably, the monomeric compound ICM having at least two primary amino groups is selected from the group consisting of 1,4-diaminobutane, 1,6-diaminohexane, 2-methyl-1,5-diaminopentane and mixtures thereof.

[0034] Preferably, the monomeric compound ICM having at least one hydroxyl group and at least one primary amino group is selected from the group consisting of ethanolamine, propanolamine, 2-(2-amino-ethylamino-)ethanol and mixtures thereof.

[0035] The monomer compound ICM is one or more monomeric compounds having at least two hydroxyl groups and one or more monomeric compounds having at least two primary amino groups, or one or more monomeric compounds having at least two hydroxyl groups, and one or more compounds having at least one hydroxyl group and at least one primary amino group, or one or more monomeric compounds having at least two primary amino groups, and one or more compounds having at least one hydroxyl group and at least one primary amino group, or -one or more monomeric compounds having at least two hydroxyl groups, one or more monomeric compounds having at least two primary amino groups, and one or more compounds having at least one hydroxyl group and at least one primary amino group. The mixture may include:

[0036] Preferably, the polymeric compound ICP having at least two isocyanate-reactive groups is a polymeric compound ICP having at least two hydroxyl groups.

[0037] Preferably, the polymeric compound ICP is characterized by a hydroxyl number comprised between 20 and 400 mg KOH / g, more preferably between 40 and 300 mg KOH / g, most preferably between 50 and 250 mg KOH / g.

[0038] The polymeric compound ICP can be derived from petrochemical feedstocks.

[0039] Preferably, the polymeric compound ICP having at least two hydroxyl groups is selected from the group consisting of polyesters having at least two hydroxyl groups ICP1, polyethers having at least two hydroxyl groups ICP2, polycarbonates having at least two hydroxyl groups ICP3, and mixtures thereof.

[0040] The polyester ICP1 having at least two hydroxyl groups preferably has two hydroxyl groups and is prepared from a stoichiometric excess of one or more diols and one or more diacids, said diols are preferably selected from the group consisting of 1,2-ethanediol, 1,2- and 1,3-propanediol, 1,2- and 1,4-butanediol, 2,2'-oxydi(ethan-1-ol), 2,2-dimethyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,4-bis-hydroxymethylcyclohexane, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,18-octadecanediol, 1,21-heneicosanediol, 1,25-pentacosanediol, isosorbide, isomannide, isoidide and mixtures thereof; said diacids are preferably selected from the group consisting of malonic acid, succinic acid, glutaric acid, adipic acid, octanedioic acid, and dimer fatty acids having up to 40 carbon atoms, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid and mixtures thereof.

[0041] Optionally, one or more hydroxycarboxylic acids, such as hydroxybenzoic acid, lactic acid, gamma hydroxybutyric acid, δ-hydroxyvaleric acid, and ε-hydroxycaproic acid, may be used in combination with one or more diols to prepare the hydroxyl functional polyester ICP1.

[0042] Preferably, polyester ICP1 is a condensation product of a diacid selected from the group consisting of adipic acid, isophthalic acid and mixtures thereof, with a stoichiometric excess of a diol selected from the group consisting of 1,4-butanediol, 1,6-hexanediol, 2,2'-oxydi(ethan-1-ol), 2,2-dimethyl-1,3-propanediol and mixtures thereof, said polyester being characterized by a hydroxyl number comprised between 20 and 400 mg KOH / g, preferably between 30 and 250 mg KOH / g, more preferably between 40 and 150 mg KOH / g, and an acid number less than 3 mg KOH / g, preferably less than 2 mg KOH / g, more preferably less than 1 mg KOH / g, said acid number being generated by residual and terminal unreacted acid functionalities.

[0043] In an alternative and preferred method, where possible, the diol (e.g., 1,3-propanediol), diacid (e.g., succinic acid) or hydroxycarboxylic acid (e.g., lactic acid) used in the preparation of polyester ICP1 is obtained from renewable feedstocks.

[0044] In yet another alternative, the polyester ICP1 is derived from petrochemical and / or renewable feedstocks.

[0045] By hydroxyl-functional polyester ICP1 having two hydroxyl groups, the present invention should be understood as a polyester having approximately two hydroxyl groups and a negligible amount of carboxylic acid groups, since 100% conversion is rarely achieved.

[0046] The polyether ICP2 is preferably a poly(oxyalkylene) glycol containing between 2 and 6 alkyl radicals, more preferably the polyether is selected from the group consisting of poly(oxyethylene) glycol, poly(oxypropylene) glycol, poly(oxytetramethylene) glycol and mixtures thereof.

[0047] Polyethers ICP2 having at least two hydroxyl groups include products obtained by polymerization of cyclic oxides, such as ethylene oxide, propylene oxide or tetrahydrofuran, or by addition of one or more such oxides to a polyfunctional initiator, such as water, ethylene glycol, propylene glycol, diethylene glycol, cyclohexane dimethanol, glycerol, trimethylolpropane, pentaerythritol or bisphenol A. Particularly useful polyethers include polyoxypropylene diols and triols, poly(oxyethylene-oxypropylene) diols and triols obtained by simultaneous or sequential addition of ethylene oxide and propylene oxide to polytetramethylene ether glycols obtained by polymerization of a suitable initiator and tetrahydrofuran. Amine-terminated polyether polyols can also be used.

[0048] Preferably, the polyether ICP2 is a poly(oxyalkylene) glycol containing between 2 and 4 alkyl radicals, more preferably the polyether is selected from the group consisting of poly(oxyethylene) glycol, poly(oxypropylene) glycol, poly(oxytetramethylene) glycol and mixtures thereof.

[0049] Alternatively and preferably, where possible, the polyether ICP2 is a poly(oxyalkylene) glycol derived from renewable feedstocks, more preferably a poly(oxyalkylene) glycol derived from bio-based 1,3-propanediol.

[0050] In yet another alternative, the polyether ICP2 is derived from petrochemical and / or renewable feedstocks.

[0051] Polycarbonate ICP3 compounds having at least two hydroxyl groups are preferably prepared by reaction of a polyol, such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, 1,4-bishydroxymethylcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane, neopentyl glycol, trimethylolpropane or pentaerythritol, with a dicarbonate, such as dimethyl, diethyl or diphenyl carbonate, or with phosgene.

[0052] Alternatively and preferably, where possible, the polycarbonate ICP3 compounds are derived from renewable feedstocks, more preferably bio-based polyols (e.g., bio-based 1,3-propanediol or 1,5-pentanediol).

[0053] In yet another alternative, the polycarbonate ICP3 compounds are derived from petrochemical and / or renewable feedstocks.

[0054] Other polymeric compounds ICP useful for the preparation of the isocyanate-functional polyurethane prepolymers A1 of the present invention include polyesteramides, polythioethers, polyacetals, polyolefins or polysiloxanes, said other compounds ICP having at least two hydroxyl groups.

[0055] The monomeric compound ICMA having at least two isocyanate-reactive groups and at least one acid group or acid group precursor, such as an anhydride, is preferably a monomer having at least two hydroxyl groups and at least one acid group or acid group precursor. More preferably, the one or more ICMA monomers are selected from the group consisting of 2,2-(bishydroxymethyl)acetic acid, 2,2-(bishydroxymethyl)propionic acid, 2,2-(bishydroxymethyl)butyric acid, and mixtures thereof.

[0056] The monomeric compound ICMA having at least two isocyanate-reactive groups and at least one acid group or acid group precursor is converted to anionic dispersant groups in a later stage of the preparation of polyurethane A by converting the acid groups to acid-salt groups by the addition of one or more neutralizing compounds N.

[0057] The one or more neutralizing compounds N are preferably selected from the group consisting of primary, secondary and tertiary amines and strong Arrhenius bases, such as the hydroxides of alkali metals and alkaline earth alkali metals.

[0058] More preferably, the neutralizing compound N is selected from the group consisting of ammonia, compounds having not more than one hydroxyl group and at least one tertiary amino group per molecule, and mixtures thereof.

[0059] Most preferably, the neutralizing compound N is selected from the group consisting of ammonia, trimethylamine, N,N-dimethylaminoethanol, 1-dimethylamino-2-propanol, 1-dimethylamino-3-propanol, 1-deoxy-1-(dimethylamino)-D-glucitol, N-(2-hydroxyethyl)piperazine and mixtures thereof.

[0060] The carbonyl functional building block A2 has the formula R 1 -NH-R 2 wherein R 1 is an alkyl or hydroxyalkyl moiety, and R 2 is a molecular entity containing a carbonyl group and is the reaction product of an α,β ethylenically unsaturated containing compound containing a carbonyl group A21 with a primary amine A22 selected from the group consisting of C1-C6 alkylamines, C1-C6 alkanolamines and mixtures thereof.

[0061] The primary alkylamine A22 is selected from the group consisting of methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, n-amylamine, isoamylamine, n-hexylamine, 2-aminohexane, isohexylamine, 3,3-dimethyl-2-butanamine, 2-amino-4-methylpentane, 3,3-dimethylbutylamine, 3,3-dimethyl-2-butylamine, 1-amino-2-ethyl-n-butane, 3-amino-3-methylpentane and mixtures thereof.

[0062] Preferably, the primary alkylamine A22 is selected from the group consisting of one or more structures of formula CH3-(CH2)n-NH2, where n is an integer from 1 to 5 (or H-(CH2)n-NH2, where n is an integer from 1 to 6), more preferably the primary alkylamine A22 is butylamine.

[0063] Primary alkanolamines A22 are methanolamine, ethanolamine, 3-amino-1-propanol, 3-amino-2-propanol, 1-amino-2-propanol, 4-amino-1-butanol, 3-amino-1-butanol, 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, 5-amino-1-pentanol, 4-amino-1-pentanol, 3-amino-1-pentanol, 2-amino-1-pentanol, 5-amino-2-pentanol, 4-amino-2-pentanol, 3-amino-2-pentanol, The amino acid residue is selected from the group consisting of ethanol, 1-amino-3-pentanol, 2-amino-3-pentanol, 4-amino-2-methyl-1-butanol, 4-amino-3-methyl-1-butanol, 2-amino-3-methyl-1-butanol, 4-amino-2-methyl-2-butanol, 3-amino-2,2-dimethyl-1-propanol, 6-amino-1-hexanol, 2-amino-1-hexanol, 3-amino-1-hexanol, 6-amino-3-hexanol, 2-amino-3-methylpentan-1-ol and mixtures thereof.

[0064] Preferably, the primary alkanolamine A22 is selected from the group consisting of one or more structures of formula HO-(CH2)n-NH2, where n is an integer from 1 to 6, more preferably the primary alkanolamine A22 is an ethanolamine.

[0065] The α,β-ethylenically unsaturated group containing compounds containing a carbonyl group A21 include acrolein, methacrolein, diacetone acrylamide, crotonaldehyde, 4-vinylbenzaldehyde, vinyl alkyl ketones of 4 to 7 carbon atoms (such as vinyl methyl ketone), as well as compounds of the formula: CH2=CHR 3 -C=OO-CHR 4 -CR 5 R 6 -C=OR 7 , (In the formula, R 3 is H or methyl, and R 4 is H or alkyl having 1 to 3 carbon atoms, and R 5 is an alkyl group having 1 to 3 carbon atoms; R 6 is an alkyl group having 1 to 4 carbon atoms; R 7 is H or alkyl having 1 to 3 carbon atoms), and is selected from the group consisting of acryloyloxy and methacryloyloxy alkyl propanols.

[0066] Preferably, the α,β ethylenically unsaturated group containing compound containing a carbonyl group A21 is diacetone acrylamide.

[0067] As is known in the art, the reaction of a primary amine A22 with an α,β ethylenically unsaturated group-containing compound containing a carbonyl group A21 is a Michael addition reaction in which A22 is the Michael donor and A21 is the Michael acceptor.

[0068] The polyurethane A of the present invention is isocyanate-functional polyurethane prepolymers A1, - a secondary amine of the carbonyl-functional building block A2, any primary amine of compound A22, is the reaction product of The carbonyl-functional building blocks A2 and optional compounds A22 are attached to the isocyanate-terminated polyurethane prepolymer A1 by urea bonds.

[0069] Preferably, polyurethane A is, for every 100 isocyanate equivalents of isocyanate-functional polyurethane prepolymer A1, isocyanate-functional polyurethane prepolymers A1, - 50 to 100 mol, preferably 70 to 99 mol, of a secondary amine of carbonyl-functional building block A2, - 0 to 50 mol, preferably 1 to 30 mol, of any compound A22 primary amine, It is the reaction product of

[0070] Preferably, the carbonyl group is of the ketone or aldehyde type.

[0071] The carbonyl-functional building blocks A2 are attached at the ends of the isocyanate-functional polyurethane prepolymer A1 to provide a polyurethane A that contains terminal carbonyl groups.

[0072] The polyurethane A of the present invention is substantially free of pendant carbonyl groups, i.e. the polyurethane comprises less than 5%, preferably less than 4%, more preferably less than 3%, most preferably less than 2%, most preferably less than 1%, most preferably 0% pendant carbonyl groups, relative to the total number of carbonyl groups, where pendant carbonyl groups are to be understood as carbonyl group containing molecular entities attached to the polyurethane at positions along the entire length of the polyurethane, but not at the ends of the polyurethane.

[0073] Preferably, polyurethane A contains only terminal carbonyl groups and no pendant carbonyl groups.

[0074] Preferably, polyurethane A contains a carbonyl group at at least one end thereof, more preferably polyurethane A contains a carbonyl group at all ends thereof, and most preferably polyurethane A is a linear polyurethane containing carbonyl groups at both ends thereof.

[0075] Polyurethane A is characterized in its solid non-neutralized form by a weight average molecular weight comprised between 3,000 and 30,000 g / mol, preferably between 5,000 and 20,000 g / mol, more preferably between 7,000 and 20,000 g / mol and most preferably between 7,000 and 15,000 g / mol.

[0076] Polyurethane A, in its solid non-neutralized form, is characterized by a carbonyl content of more than 150 mmol / kg, preferably between 170 and 700 mmol / kg, more preferably between 200 and 700 mmol / kg, most preferably between 250 and 700 mmol / kg or even between 300 and 700 mmol / kg.

[0077] Polyurethane A, in its solid, unneutralized form, is -0 mmol / kg hydroxyl content (The carbonyl functional building block A2 is the reaction product of an α,β ethylenically unsaturated group containing compound containing a carbonyl group A21 and a C1-C6 primary alkylamine A22, any primary amine A22 is a C1-C6 primary alkylamine, or by a hydroxyl content of at least 250 mmol / kg, preferably between 250 mmol / kg and 650 mmol / kg, more preferably between 350 mmol / kg and 550 mmol / kg (The carbonyl-functional building block A2 is the reaction product of an α,β-ethylenically unsaturated group containing compound containing a carbonyl group A21 and a C1-C6 primary alkanolamine A22, any primary amine A22 is a C1-C6 primary alkanolamine, or - by a hydroxyl content comprised between 5 mmol / kg and at least 250 mmol / kg, preferably between 10 mmol / kg and 640 mmol / kg, more preferably between 20 mmol / kg and 530 mmol / kg (The carbonyl functional building block A2 is a reaction product of an α,β ethylenically unsaturated containing compound containing a carbonyl group A21 and a primary amine A22, which contains a mixture of C1-C6 primary alkylamines and C1-C6 primary alkanolamines; Optional primary amine A22 is a mixture of C1-C6 alkylamines and C1-C6 alkanolamines. Can be characterized.

[0078] Polyurethane A, in its solid non-neutralized form, is characterized by an acid content, derived from the pendant acid groups of the monomeric compound ICMA, of between 300 and 700 mmol / kg, preferably between 350 and 650 mmol / kg, more preferably between 400 and 600 mmol / kg, and most preferably between 450 and 550 mmol / kg.

[0079] By polyurethane A, in its solid non-neutralized form, the invention is to be understood as follows. -Non-neutralized polyurethane A (Polyurethane A in which the carboxylic acid groups or acid group precursors of monomeric compound ICMA are not converted to anionic dispersant groups by the addition of one or more neutralizing compounds N. In its unneutralized form, Polyurethane A contains pendant acid groups or acid group precursors). -Solid Polyurethane A (Polyurethane A, not including the deionized water added with carbonyl-functional building block A2 for the preparation of carbonyl-terminated non-neutralized polyurethane A)

[0080] Polyfunctional compounds B having functional groups capable of reacting with the carbonyl groups of polyurethane A include polyhydrazides and polyhydrazones. Examples of such polyhydrazides and polyhydrazones include: formula: -H2N-NH-C(O)-R 8 -C(O)-NH-NH2 dicarboxylic acid bishydrazide, and formula: R 9 R 10 C=N-NH-C(O)-R 8 -C(O)-NH-N=CR 9 R 10 Dicarboxylic acid bishydrazone (In the formula, R 8 is a covalent bond, a polyalkylene (preferably polymethylene), an alicyclic group having 1 to 34 carbon atoms, or a divalent aromatic ring; R 9 and R 10 is selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups. Examples of suitable dihydrazides include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, cyclohexanedicarboxylic acid dihydrazide, azelaic acid dihydrazide, and sebacic acid dihydrazide.

[0081] Other suitable compounds B are polyhydrazides of carbonic acid, such as carbonic acid dihydrazides and compounds of the general formula: H2N-NH-CO-(NH-NH-CO-) x -NH-NH2 (wherein x is 1 to 5, preferably 1 to 3), and Bisemicarbazides, in particular those of the general formula: H2N-NH-CO-NH-R 11 -HN-CO-NH-NH2 Aliphatic and alicyclic bissemicarbazides of the formula: 11 - is a linear or branched aliphatic radical of 2 to 7 carbon atoms or a carbocyclic radical of 6 to 8 carbon atoms, for example o-, m- or p-phenylene or toluene or cyclohexylidene or methylcyclohexylidene) It is a compound of the formula: Other suitable compounds B are polyhydrazides of aromatic polycarboxylic acids, such as the dihydrazides of phthalic acid, terephthalic acid and isophthalic acid, and also the dihydrazides, trihydrazides and tetrahydrazides of pyromellitic acid. Other suitable compounds B are trihydrazides, such as nitrilotriacetic acid trihydrazide, and tetrahydrazides, such as ethylenediaminetetraacetic acid tetrahydrazide. Other suitable compounds B are dihydrazino- and trihydrazino-triazines, thiocarbohydrazides and N,N'-diaminoguanidines, as well as hydrazinopyridine derivatives of the type 2-hydrazino-pyridine-5-carboxylic acid hydrazide, 3-chloro-2-hydrazinopyridine-5-carboxylic acid hydrazide, 6-chloro-2-hydrazinopyridine-4-carboxylic acid hydrazide and 2,5-dihydrazinopyridine-4-carboxylic acid and bis-thiosemicarbazide, as well as bis-hydrazines of alkylene-bis-acrylamides, dihydrazines of dihydrazinoalkanes and aromatic hydrocarbons, such as 1,4-dihydrazinobenzene, 1,3-dihydrazinobenzene and 2,3-dihydrazinonaphthalene.

[0082] Preferably, the polyfunctional compound B is adipic dihydrazide.

[0083] Preferably, the aqueous polyurethane dispersion of the present invention contains polyurethane A having pendant acid salt groups and terminal carbonyl functional groups, and polyfunctional compound B, and the molar ratio of the carbonyl functional groups of polyurethane A to the (hydrazide) functional groups of polyfunctional compound B is 0.7 to 1.3, preferably 0.8 to 1.2, and more preferably 0.9 to 1.1.

[0084] The aqueous dispersion comprising the polyurethane A and the polyfunctional compound B is preferably - Solids content between 30% and 60% (by weight) -Kinematic viscosity at 23°C and 100 rpm according to ISO2555-1974, between 50 and 5,000 mPa.s; - pH between 7 and 8.5 according to DIN 19268; - Z-average particle size according to ISO 22412 comprised between 20 and 150 nm; It is characterized by:

[0085] The aqueous polyurethane dispersion is a. mixing one or more polymeric compounds ICP having at least two isocyanate-reactive groups with one or more monomers ICM having at least two isocyanate-reactive groups in the presence of one or more isocyanate-reactive monomers ICMA having at least two isocyanate-reactive groups and an acid group or a group capable of forming an acid when contacted with water, and heating the mixture under stirring at a temperature of at least 60°C, preferably at least 80°C, more preferably at least 100°C, most preferably at least 120°C for at least 10 minutes, preferably at least 20 minutes; b. continuously adding substoichiometric amounts of one or more polyfunctional isocyanates I to the mixture of step a) over a period of 10 minutes to 80 minutes, preferably 20 minutes to 70 minutes, more preferably 30 minutes to 60 minutes while maintaining the temperature in the range of 60° C. to 150° C., preferably 80° C. to 140° C., more preferably 100° C. to 135° C., to form a hydroxyl-functional polyurethane prepolymer; c. maintaining the reaction product of step b) at a temperature comprised between 120 and 135°C, preferably between 130 and 135°C, for 30 to 90 minutes, preferably between 40 and 80 minutes, more preferably between 50 and 70 minutes, followed by cooling to a temperature comprised between 60 and 100°C, preferably between 70 and 90°C; d. adding at once, with stirring at a temperature between 60°C and 130°C, preferably between 70°C and 90°C, to the hydroxyl-functional polyurethane prepolymer of step c), a stoichiometric excess of a further amount of one or more polyfunctional isocyanates I, optionally in the presence of one or more compounds ICM and ICMA, and continuing the reaction at a temperature between 70°C and 150°C, preferably between 75°C and 90°C, for at least 1 hour, preferably comprised between 1 and 3 hours, more preferably comprised between 1 and 2 hours, to form an isocyanate-functional polyurethane prepolymer A1 (confirmed by titration) having an isocyanate value corresponding to the theoretical value of 1; e. adding a mixture of carbonyl-functional building blocks A2, optionally one or more primary amines A22 and optionally water all at once to the isocyanate-functional polyurethane prepolymer A1 of step d) at rest at a temperature comprised between 70 and 95°C, preferably between 75 and 90°C, and homogenizing at the obtained temperature for at least 10 minutes, preferably at least 15 minutes, to convert the isocyanate-functional polyurethane prepolymer A1 into a polyurethane containing terminal carbonyl groups; f. adding one or more neutralizing agents N at a time to the polyurethane of step e) containing acid groups and carbonyl groups in water and homogenizing for at least 10 minutes, preferably at least 15 minutes, to convert the acid groups to the corresponding salts and obtain polyurethane A; g. adding deionized water preheated at a temperature comprised between 50 and 70°C, preferably between 55 and 65°C, continuously to the polyurethane A of step f) under vigorous stirring for at least 10 minutes, preferably at least 15 minutes, and homogenizing at a temperature comprised between 50 and 70°C, preferably between 55 and 65°C, for at least another 20 minutes, preferably at least another 30 minutes to form an aqueous dispersion of polyurethane A; h. cooling the aqueous dispersion of polyurethane A of step g) to a temperature below 40° C., preferably below 30° C., and optionally adding a multifunctional compound B; i. adding deionized water to the aqueous dispersion of step h) comprising polyurethane A and optionally polyfunctional compound B to adjust the solids content to 40+ / -1% (by weight); It is prepared in a multi-step process including:

[0086] Calculation of theoretical isocyanate values, as well as confirmation thereof by titration, are well known to those skilled in the art and are routinely performed.

[0087] Addition in one go in steps d) to f) is to be understood as addition over a period of time that is at least 50% less, preferably at least 60% less, more preferably at least 70% less, most preferably at least 80% less, or even at least 90% less than the homogenization time of the final mixture.

[0088] The carbonyl functional building block A2 added in step e) is heating A21 under nitrogen at a temperature comprised between 50 and 80°C, preferably between 60 and 70°C, until completely melted; adding A22 in a molar excess of 1 to 45 percent, preferably 1 to 35 percent, at once; heating the mixture of A21 and A22 at a temperature between 60° C. and 85° C., preferably between 65° C. and 80° C., for a period of time between 1 h and 24 h, preferably between 1 h and 15 h, until complete conversion of the ethylenically unsaturated bonds, as confirmed by Fourier transform infrared spectroscopy (FTIR); It is prepared in a separate reaction by

[0089] Addition of A22 to A21 in one go should be understood as addition over a period of time that is at least 50% less, preferably at least 60% less, more preferably at least 70% less, most preferably at least 80% less, or even at least 90% less than the homogenization time of the mixture of A22 and A21.

[0090] The aqueous dispersions of the present invention are preferably used in aqueous coating compositions further comprising one or more additives selected from the group consisting of organic solvents, defoamers, coalescing agents, flow control agents, rheological additives, fillers, pigments, active pigments, dyes, wetting agents, emulsifiers, surfactants, thickeners, heat stabilizers, leveling agents, anti-crush agents, anti-settling agents, UV absorbers and antioxidants.

[0091] Alternatively, the aqueous polyurethane dispersion of the present invention can be used in an aqueous adhesive composition. More specifically, the aqueous adhesive composition comprises the aqueous polyurethane dispersion and one or more additives selected from the group consisting of organic solvents, defoamers, fusing agents, flow control agents, rheological additives, fillers, pigments, active pigments, dyes, wetting agents, emulsifiers, surfactants, thickeners, heat stabilizers, leveling agents, anti-fracture agents, anti-settling agents, UV absorbers, and antioxidants.

[0092] The aqueous coating composition of the present invention can be applied to a wide variety of substrates selected from the group consisting of wood, engineered wood, metal, glass, fabric, composites, concrete, ceramic, leather, paper, plastics and foam.

[0093] The water-based coating composition can be applied to a substrate by any conventional method including brushing, flow coating, roll coating, drawdown, coil coating, curtain coating, immersion coating, dip coating, spray coating, vacuum coating, and the like.

[0094] Generally, the water-based coating composition is applied at a liquid coating thickness adapted to obtain a dry film thickness comprised between 5 and 50 μm, preferably between 8 and 40 μm, more preferably between 10 and 30 μm, and most preferably between 10 and 20 μm.

[0095] The water-based coating composition provides a self-crosslinking reaction via azomethine formation during and / or after film formation. EXAMPLES

[0096] The following illustrative examples are intended merely to illustrate the present invention and are not intended to limit or define the scope of the present invention.

[0097] Example 1: Synthesis of keto-functional building block A2 by Michael addition A nitrogen purged reactor was charged with 150.00 g (0.8864 mol) of solid diacetone acrylamide (A21) and heated to 65°C until the material was completely melted. A slight molar excess of 72.19 g (1.1819 mol) of ethanolamine (A22) was then added to the reactor in one go and the resulting reaction mixture was stirred at 70°C-75°C for 1-4 hours until complete conversion of the double bonds of diacetone acrylamide as confirmed by FTIR measurements. The reaction product was then cooled to ambient temperature and used as a crude product without further purification in the synthesis of carbonyl terminated polyurethanes. The keto functional building block (A2) was characterized by a keto content of 3.9894 mmol / g, an amino content of 5.3193 mmol / g and a hydroxyl content of 5,3193 mmol / g.

[0098] Examples 2 and 3: Synthesis of keto-functional building blocks A2 by Michael addition Table 1 reproduces the composition of the keto-functional building block A2 of Examples 2-3. The keto-functional building block A2 of Examples 2 and 3 was prepared according to the process of Example 1.

[0099] [Table 1]

[0100] Example 4: Synthesis of an aqueous dispersion containing polyurethane A having pendant acid groups and terminal carbonyl groups and polyfunctional compound B A nitrogen purged reactor was charged with 275.21 g (0.201 moles) of polyester diol (ICP) (consisting of 18.2% 1,6-hexanediol, 18.1% diethylene glycol, 11.5% neopentyl glycol, 18.4% isophthalic acid and 33.8% adipic acid), 0.15 g (0.0014 moles) of neopentyl glycol (ICM) and 31.33 g (0.2344 moles) of dimethylol propionic acid (ICMA), followed by heating to 130°C and homogenization at 130°C for 30 minutes. Then, 26.10 g (0.1499 moles) of toluene diisocyanate (I) was added continuously over a period of 45-60 minutes, thereby constantly maintaining the resulting reaction temperature in the range of 130°C-135°C. After the entire amount of toluene diisocyanate (I) was added, the resulting reaction mixture was maintained at 130°C-135°C for 1 hour and then cooled to 80°C. Then, 101.31 g (0.4147 moles) of meta-tetramethyl xylylene diisocyanate (TMXDI) (I) was added to the reactor in one portion and the resulting reaction mixture was stirred at 80°C-85°C until the theoretical isocyanate value was reached, as confirmed by titration. The typical reaction time for this step was 1-2 hours at a temperature of 80°C-85°C. As soon as the theoretical isocyanate value was confirmed by titration, a mixture of 9.92 g of the keto-functional building block (A2) of Example 1 in deionized water was added to the reaction mixture in one portion and homogenized at the resulting reaction temperature for 15 minutes. Then, dimethylethanolamine neutralizer (N) in 100 g of deionized water was added to the reactor in one portion and homogenized at the resulting reaction temperature for 15 minutes. 550 g of deionized water preheated to 60° C. was then added continuously to the reactor with vigorous stirring over a period of 15 minutes, and the resulting emulsion was homogenized for another 30 minutes at 60° C. The reaction mixture was then cooled to a temperature below 40° C., and 15.31 g (0.087 moles) of adipic dihydrazide (B) was added and homogenized for 15 minutes. Adjustment of the solids content of the final emulsion to 40+ / -1% was performed by addition of 62.42 g of deionized water. The polyurethane dispersion is characterized by a solids content of 40.1% (by weight), a pH (10% aqueous solution) of 7.6, a Z-average particle size of 25 nm, and a dynamic viscosity of 1802 mPa.s.The solid non-neutralized polyurethane (A) is characterized by a weight average molecular weight (Mw) of 10,030 g / mol, a keto content of 368 mmol / kg, a hydroxyl content of 490 mmol / kg and an acid content of 490 mmol / kg.

[0101] Examples 5-9: Synthesis of an aqueous dispersion containing a carbonyl-terminated polyurethane A having pendant acid groups and terminal carbonyl groups and a multifunctional compound B In Table 2, the compositions of the aqueous dispersions containing carbonyl-terminated polyurethane A having pendant acid salt groups and terminal carbonyl groups, and multifunctional compound B are reproduced for Examples 5 to 9. The aqueous dispersions of Examples 5 to 9 were prepared according to the process of Example 4.

[0102] [Table 2-1] [Table 2-2]

[0103] Comparative Examples 10 to 12 Table 3 lists the compositions of the aqueous dispersions of Comparative Examples 10-12, which were prepared according to the process of Example 4, with the following exceptions. For Comparative Example 10, the keto-functional building block A2 of Example 2 is added to the hydroxyl-functional polyurethane prepolymer prior to the addition of the second polyisocyanate I, and a primary alkanolamine A22 is added to the isocyanate-terminated polyurethane A1 resulting from the second addition of polyisocyanate I to the hydroxyl-functional polyurethane prepolymer, the final polyurethane being a hydroxyl-terminated polyurethane containing pendant carbonyl groups. For comparative example 11, there is no addition of keto-functional building block A2, only primary alkanolamine A22 is added to the isocyanate-terminated polyurethane A1, the final polyurethane being a hydroxyl-terminated polyurethane containing no carbonyl groups. For comparative example 12, there is no addition of keto-functional building block A2, but only a primary alkylamine A22 is added to the isocyanate-terminated polyurethane A1, and the final polyurethane is an alkyl group-terminated polyurethane that does not contain carbonyl groups.

[0104] [Table 3-1] [Table 3-2]

[0105] Coating formulations, coating applications, test results Application tests were carried out using ABS / PC plastic panels (BAYBLEND™ T65XF, Covestro AG) used in multiple applications such as automotive interiors and household goods. The following formulations were prepared:

[0106] Example 13: Preparation of Basecoat Formulation Basecoat coating formulations were prepared from the aqueous polyurethane dispersions of Examples 4, 8 and 9 and Comparative Examples 10, 11 and 12 according to the formulations in Table 4. [Table 4]

[0107] Dimethylethanolamine solution (10% strength solution in deionized water) and deionized water (part Q1) were added to the aqueous polyurethane dispersions of Examples 4, 8, 9 and Comparative Examples 10, 11, 12 and homogenized with a mechanical stirrer at 900 revolutions per minute. A 10% strength solution of an acrylic copolymer thickener in deionized water (RHEOVIS™ AS 1130, BASF AG) was stirred for 15 minutes, after which a 3% strength solution of a silicate thickener (LAPONITE™ RD, BYK AG) and further deionized water (part Q2) were added and homogenized for a further 10 minutes at 900 revolutions per minute. The aluminum flake slurry (Part Q3) was prepared in a separate step by charging aluminum flake (silica encapsulated aluminum flake, HYDROLAN™ S-2100, Eckart GmbH), adding anionic wetting agent (ADDITOL XL™ 250, allnex GmbH) and butyl glycol, and homogenizing with a mechanical stirrer at 600 rpm for 30 min. The homogenized Part Q3 was then added to the premixed Parts Q1 and Q2 with stirring at 900 rpm, and homogenized for another 20 min.

[0108] The base coat thus prepared was left to stand for 12 hours at ambient temperature (23°C). Then parts Q4 (wax additive) and Q5 were added and homogenized for another 5 minutes at 900 RPM. Finally, the formulation was completed with part Q6 and homogenized for another 5 minutes at 700 RPM.

[0109] Example 14: Preparation of Clearcoat Formulation Two-part clearcoat compositions were prepared according to the formulations in Table 5. [Table 5]

[0110] The ingredients of Part X were mixed for 15 minutes at 700 revolutions per minute. Before application, a premix of HDI trimer isocyanate crosslinker (DESMODUR brand) N 3390, Coverstro AG, diluted with butyl acetate was added to the mixed Part X (Part Y). Finally, the spray application was adjusted to 21 seconds (DIN 4 cup, 23°C, DIN EN ISO 2431) with the premixed solvent composition of Part Z.

[0111] Example 15: Preparation of test panels The ABS / PC plastic panels containing the basecoat of Example 13 and the clearcoat of Example 14 are shown in Table 6. The coating formulations were applied using a pneumatic spray gun (SATA RP 3000 / 4000 / 5000) at an air pressure of about 1.5-2.0 bar. First, the basecoat formulation was applied at a dry film thickness of about 17+ / -2μm. After application, and after a flash-off time of 10 minutes, a baking step at 60°C (10 minutes) was performed on the applied basecoat formulation. Immediately after the baking step, the clearcoat formulation was applied at a dry film thickness of about 40-45μm. After a flash-off time of 10 minutes, all panels were cured in an oven at 80°C for 30 minutes, followed by a post-cure step at 70°C for 12 hours.

[0112] [Table 6]

[0113] Example 16: Moisture resistance test Panels 1-6 were subjected to a humidity resistance test (hydrolysis aging) according to Volkswagen standard TL 226 carried out in a humidity chamber at 90 + / - 2 °C and a relative humidity of more than 96% for 72 hours. Prior to the evaluation of the intercoat adhesion, after conditioning at room temperature for 4 hours after the test, the intercoat adhesion between the base coat and the clear coat was evaluated in a cross-cut test by tape pull-off (DIN EN ISO 2409) with 0 = complete adhesion and 5 = complete peeling. The test results are shown in Table 7.

[0114] [Table 7]

[0115] As can be seen from Table 7, the use of the novel aqueous polyurethane dispersion according to the present invention as a basecoat layer in a multi-layer (basecoat-clearcoat) system unexpectedly results in significantly improved intercoat adhesion after hot water resistance testing.

Claims

1. A polyurethane A having a pendant acid base and a carbonyl group present at the terminal, and optionally, a polyfunctional compound B having a functional group capable of reacting with the carbonyl group of the polyurethane A An aqueous polyurethane dispersion comprising: The polyurethane A, in its solid non-neutralized form, has a weight average molecular weight of between 3,000 and 30,000 g / mol as measured by GPC in tetrahydrofuran calibrated with polystyrene standards, is characterized by a carbonyl content of more than 150 mmol / kg, The polyurethane A is an isocyanate-functional polyurethane prepolymer A1 containing an acid group, 50 to 100 moles of a carbonyl-functional component A2 (the carbonyl-functional component A2 is a reaction product of an α,β ethylenically unsaturated group-containing compound containing a carbonyl group A21 and a primary amine A22, and the primary amine A22 is selected from the group consisting of alkylamines, alkanolamines and mixtures thereof) per 100 isocyanate equivalents of the isocyanate-functional polyurethane prepolymer A1, 0 to 50 moles of a primary amine A22 (the primary amine A22 is selected from the group consisting of alkylamines, alkanolamines and mixtures thereof) per 100 isocyanate equivalents of the isocyanate-functional polyurethane prepolymer A1, one or more acid-neutralizing compounds N, and is a reaction product of wherein the carbonyl-functional component A2 has the formula R １ -NH-R ２ (wherein R １ is an alkyl or hydroxyalkyl moiety and R ２ is a molecular entity containing a carbonyl group), and contains a secondary amine group the carbonyl-functional component A2 is bonded to the isocyanate-functional polyurethane prepolymer A1 by a urea bond, the carbonyl-functional component A2 is bonded to the terminal of the isocyanate-functional polyurethane prepolymer A1, An aqueous polyurethane dispersion.

2. The aqueous polyurethane dispersion according to claim 1, wherein the polyurethane A, in its solid non-neutralized form, A hydroxyl content of 0 mmol / kg (where R １ is an alkyl group and any additional alkylamine), whereby a hydroxyl content of at least 250 millimoles / kg (R １ being a hydroxyalkyl group and any additional alkanolamine), or The hydroxyl content (R １ which is a mixture of an alkyl group and a hydroxyalkyl group, and also an optional additional alkylamine, alkanolamine, or a mixture thereof) by is characterized by an aqueous polyurethane dispersion.

3. The aqueous polyurethane dispersion according to claim 1, wherein the carbonyl group of the carbonyl-functional component A2 is of the ketone and / or aldehyde type.

4. The aqueous polyurethane dispersion according to claim 1, wherein the carbonyl-functional component A2 is A compound containing a carbonyl group A21, an α,β ethylenically unsaturated group (the α,β ethylenically unsaturated group being a vinyl alkyl ketone having 4 to 7 carbon atoms such as acrolein, methacrolein, diacetone acrylamide, crotonaldehyde, 4-vinylbenzaldehyde, vinyl methyl ketone, and a compound containing a carbonyl group A21 selected from the group consisting of acryloxy- and methacryloxy-alkylpropanols of the formula CH ２ =CHR ３ -C=O-O-CHR ４ -CR ５ R ６ -C=O-H (wherein R ３ is H or methyl, R ４ is H or alkyl having 1 to 3 carbon atoms, R ５ is alkyl having 1 to 3 carbon atoms, R ６ is alkyl having 1 to 4 carbon atoms)), and a primary amine A22 selected from the group consisting of C1-C6 alkylamines, C1-C6 alkanolamines and mixtures thereof, An aqueous polyurethane dispersion which is a Michael addition reaction product.

5. An aqueous polyurethane dispersion according to Claim 1, wherein the carbonyl-functional component A2 is Formula HO-(CH ２ )n-NH ２ and / or H-(CH ２ )n-NH ２ and a primary amine A22 (wherein n is an integer from 1 to 6), diacetone acrylamide A21 and An aqueous polyurethane dispersion which is a Michael addition reaction product.

6. An aqueous polyurethane dispersion according to Claim 1, wherein the isocyanate-functional polyurethane prepolymer A1 is one or more polyisocyanates I and one or more isocyanate-reactive compounds IC having at least two isocyanate-reactive groups selected from the group consisting of monomer compounds ICM, polymer compounds ICP and mixtures thereof, one or more isocyanate-reactive monomers ICMA having at least two isocyanate-reactive groups and a group capable of forming an acid when contacted with at least one acid group or water, is a reaction product of An aqueous polyurethane dispersion in which the isocyanate groups of I are stoichiometrically in excess of the isocyanate-reactive groups of IC and ICMA.

7. The aqueous polyurethane dispersion according to Claim 1, wherein the polyfunctional compound B is present and contains at least two hydrazide functional groups.

8. The aqueous polyurethane dispersion according to Claim 1, wherein the polyfunctional compound B is present and is a reaction product of hydrazine and a polycarboxylic acid.

9. The aqueous polyurethane dispersion according to Claim 1, wherein the polyfunctional compound B is present and is selected from the group consisting of oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide cyclohexanedicarboxylic acid dihydrazide, azelaic acid dihydrazide, and sebacic acid dihydrazide.

10. The aqueous polyurethane dispersion according to Claim 1, wherein the polyfunctional compound B is present and is adipic acid dihydrazide.

11. The aqueous polyurethane dispersion according to Claim 1, wherein the molar ratio of the carbonyl functional group of polyurethane A to the functional group of the polyfunctional compound B is 0.7 to 1.

3.

12. A method for preparing the aqueous polyurethane dispersion according to Claim 1, a. One or more polymer compounds ICP having at least two isocyanate-reactive groups are mixed with one or more isocyanate-reactive monomers ICMA having at least two isocyanate-reactive groups and a group capable of forming an acid when contacted with at least two isocyanate-reactive groups and an acid group or water, and the mixture is heated to a temperature of at least 60° C. for at least 10 minutes with stirring; b. While maintaining the temperature in the range of 60° C. to 150° C., a stoichiometrically excessive amount of one or more polyfunctional isocyanates I is continuously added to the mixture of step a) over a period of 10 minutes to 80 minutes to form a hydroxyl-functional polyurethane prepolymer; c. Maintaining the reaction product of step b) at a temperature comprised between 120 and 135° C. for a period of 30 to 90 minutes and subsequently cooling to a temperature comprised between 60 and 100° C.; d. While stirring at a temperature of 60° C. to 130° C., a stoichiometrically excessive further amount of one or more polyfunctional isocyanates I is added at once to the hydroxyl-functional polyurethane prepolymer of step c), optionally in the presence of one or more compounds ICMA and ICMA, and the reaction is continued at a temperature of 70° C. to 150° C. for at least 1 hour to form an isocyanate-functional polyurethane prepolymer A1 having an isocyanate value corresponding to a theoretical value of 1; e. A mixture of compound A2, optionally one or more primary amines A22, and optionally water is added at once to the isocyanate-functional polyurethane prepolymer A1 of step d) while standing at a temperature comprised between 70 and 95° C., and homogenized at the resulting temperature for at least 10 minutes to convert the isocyanate-functional polyurethane prepolymer A1 into a polyurethane containing a carbonyl group present at the end; f. One or more neutralizing agents N are added at once to the polyurethane of step e) containing acid groups and carbonyl groups in water and homogenized for at least 10 minutes to convert the acid groups into the corresponding salts, to obtain a polyurethane A containing pendant acid salts and a carbonyl group present at the end; g. Deionized water preheated at a temperature included between 50 and 70 °C is continuously added to polyurethane A of step f) for at least 10 minutes while vigorously stirring, and further homogenized for at least 20 minutes at a temperature included between 50 and 70 °C to form an aqueous dispersion of polyurethane A; h. Cooling the aqueous dispersion of polyurethane A of step g) to a temperature below 40 °C and optionally adding a polyfunctional compound B; i. Adding deionized water to the aqueous dispersion of step h) containing polyurethane A and optionally the polyfunctional compound B to adjust the solids content to 40 ± 1% (by weight); A preparation method comprising the above steps.

13. The method according to claim 12, wherein the carbonyl-functional component A2 added in step e) is heated A21 under nitrogen at a temperature included between 50 and 80 °C until it completely melts; adding 1 to 45 percent molar excess of A22 at once; heating the mixture of A21 and A22 to a temperature included between 60 and 85 °C for a time of 1 hour to 24 hours until complete conversion of the ethylenically unsaturated bonds as confirmed by Fourier transform infrared spectroscopy; The method according to claim 12, prepared by the above steps.

14. The method according to claim 12, wherein said one or more neutralizing agents N added in step f) are selected from the group consisting of primary, secondary and tertiary amines and strong Arrhenius bases such as hydroxides of alkali metals and alkaline earth metals.

15. An aqueous polyurethane dispersion according to claim 1, and one or more additives selected from the group consisting of organic solvents, defoamers, fusing agents, flow regulators, rheology additives, fillers, pigments, reactive pigments, dyes, wetting agents, emulsifiers, surfactants, thickeners, heat stabilizers, leveling agents, anti-crushing agents, anti-settling agents, UV absorbers and antioxidants.

16. The coating composition according to claim 15, which provides a self-crosslinking reaction via azomethine formation during and / or after film formation.

17. Use of the coating composition according to claim 15 for coating a substrate selected from the group consisting of wood, engineered wood, metal, glass, cloth, composites, concrete, ceramics, leather, paper, plastics and foams.