Aqueous polyurethane dispersions and applications thereof

Abstract

The present application relates to aqueous polyurethane dispersions and applications thereof. The aqueous polyurethane dispersion comprises polyurethane and / or polyurethane-urea and aliphatic alcohol esters. The aqueous polyurethane dispersion of the present invention is capable of both maintaining stability of a dispersion emulsion under conditions of lower temperatures and providing good initial heat resistance, thereby satisfying the requirements of downstream applications.

Description

[0001] 2024PF30080-Foreign Countries

[0002] - 1 -

[0003] AQUEOUS POLYURETHANE DISPERSIONS AND APPLICATIONS

[0004] THEREOF

[0005] TECHNICAL FIELD

[0006] The present invention relates to the technical field of polyurethanes, and in particular to aqueous polyurethane dispersions and applications thereof.

[0007] BACKGROUND ART

[0008] Compared with solvent-based adhesives, aqueous polyurethane adhesives have advantages such as low volatile organic compound (VOC) emission, environmental friendliness and non-toxicity, as well as safe operation, which meet the requirements of the industry for green and environmental protection. As people's awareness of environmental protection continues to grow, aqueous polyurethane adhesives are getting widely used in fields such as automotive interior decoration and shoe materials.

[0009] However, currently aqueous polyurethane adhesives still face some challenges during application, for example, storage stability under low temperature conditions. Many aqueous polyurethane dispersions, after being stored for a period of time at low temperatures (e.g. 5 °C), may experience a drastic increase in viscosity and may even undergo gelling, which restricts the use of adhesives prepared from these aqueous polyurethane dispersions in regions or during time periods with colder climates.

[0010] In addition, typical aqueous polyurethane dispersions have relatively poor initial heat resistance, with the adhesive strength significantly decreased at the temperature of 80 °C or even 60 °C, thereby resulting in quality issues such as loss of adhesion between freshly bonded parts.

[0011] At present, practitioners in the art have tried lots of methods to improve heat resistance of polyurethane dispersions. CN104004486A discloses preparing aqueous adhesives with good heat resistance and no after-tack at 120°C by adding inorganic materials such as a siloxane coupling agent, talc, titanium dioxide and fumed silica into polyurethane dispersions. While this approach of adding inorganic components can improve the initial heat resistance, it tends to decrease the initial adhesive strength of the polyurethane dispersions per se, making them unsuitable for application scenarios with high requirements of initial adhesive strength. CN103435760A discloses preparing two- component aqueous polyurethane adhesives by adding an isocyanate curing agent into polyurethane dispersions, thereby improving the crosslinking density of the adhesives after curing, and rendering them with better heat resistance. However, this approach can effectively improve heat resistance only after crosslinking the isocyanate curing agent, 2024PF30080-Foreign Countries

[0012] - 2 - i.e. it generally takes about 3 days before this can happen, which is of little help to initial heat resistance.

[0013] Therefore, there remains a demand in the art for a aqueous polyurethane dispersion that is capable of both maintaining relative stability of a dispersion emulsion under conditions of lower temperatures (e.g. 5°C) and providing good initial heat resistance, thereby satisfying the requirements of downstream applications.

[0014] SUMMARY OF THE INVENTION

[0015] One objective of the present invention is to provide an aqueous polyurethane dispersion that is capable of both maintaining relative stability of a dispersion emulsion under conditions of lower temperatures (e.g. 5 °C) and providing good initial heat resistance.

[0016] Thus, according to a first aspect of the present invention, there is provided an aqueous polyurethane dispersion, comprising:

[0017] (i) polyurethane and / or polyurethane-urea prepared by reaction of a system comprising components a)-c) and optional components d)-e): a) at least one crystalline polyol, b) at least one polyisocyanate, c) at least one hydrophilic compound comprising NCO reactive functional groups, wherein hydrophilic groups of the hydrophilic compound comprise one or more of ionic groups, potentially ionic groups and nonionic groups, d) a small molecule alcohol different from components a) and c), comprising 1 to 4 NCO reactive functional groups and having a molecular weight of 32 to 400 g / mol, e) an additional isocyanate reactive compound, which is one or more of amine chain extenders and amine chain terminating agents, and

[0018] (ii) at least one aliphatic alcohol ester, which is a reaction product of one or more aliphatic diols and one or more C2-C18 monocarboxylic acids, wherein the amount of the at least one aliphatic alcohol ester is 1 to 8 wt.% of the solid content of the aqueous polyurethane dispersion, and the weight-average molecular weight of the polyurethane and / or polyurethaneurea is 260,000 g / mol or greater.

[0019] According to a second aspect of the present invention, there is provided a coating, an adhesive, a sealant or an ink prepared using the above aqueous polyurethane dispersion. 2024PF30080-Foreign Countries

[0020] - 3 -

[0021] According to a third aspect of the present invention, there is provided use of the coating, adhesive, sealant or ink for preparing a coated product, an adhesive product, a sealed product or a printed product.

[0022] According to a fourth aspect of the present invention, there is provided an article comprising a substrate coated, bonded, sealed or printed with said coating, adhesive, sealant or ink.

[0023] The aqueous polyurethane dispersion of the present invention is capable of both maintaining stability of a dispersion emulsion under conditions of lower temperatures (e.g. 5 °C) and providing good initial heat resistance, thereby satisfying the requirements of downstream applications.

[0024] DETAILED DESCRIPTION OF THE INVENTION

[0025] Some embodiments of the present invention are now described for the purpose of illustration rather than limitation.

[0026] Aqueous Polyurethane Dispersion

[0027] According to a first aspect of the present invention, there is provided an aqueous polyurethane dispersion, comprising:

[0028] (i) polyurethane and / or polyurethane-urea, prepared by reaction of a system comprising components a)-c) and optional components d)-e): a) at least one crystalline polyol, b) at least one polyisocyanate, c) at least one hydrophilic compound comprising NCO reactive functional groups, wherein hydrophilic groups of the hydrophilic compound comprise one or more of ionic groups, potentially ionic groups and nonionic groups, d) a small molecule alcohol different from components a) and c), comprising 1 to 4 NCO reactive functional groups and having a molecular weight of 32 to 400 g / mol, e) an additional isocyanate reactive compound, which is one or more of amine chain extenders and amine chain terminating agents, and

[0029] (ii) at least one aliphatic alcohol ester, which is a reaction product of one or more aliphatic diols and one or more C2-C18 monocarboxylic acids, wherein the amount of the at least one aliphatic alcohol ester is 1 to 8 wt.% of the solid content of the aqueous polyurethane dispersion, and 2024PF30080-Foreign Countries

[0030] - 4 - the weight-average molecular weight of the polyurethane and / or polyurethaneurea is 260,000 g / mol or greater.

[0031] The solid content of the aqueous polyurethane dispersion in the present application refers to nonvolatile substances in the aqueous polyurethane dispersion.

[0032] The weight-average molecular weight in the present application is measured using gel chromatography. The chromatograph was a liquid chromatograph from Agilent, utilizing a polyester copolymer-type gel permeation chromatography (GPC) column with an exclusion limit of up to 1,000,000 g / mol. The concentration of the sample is approximately 0.006 g / mL, and the sample size was 100 pL. Using dimethylacetamide (DMAc) as the mobile phase, the analysis is conducted at a column temperature of 60 °C, and a differential refraction detector was employed for detection. The final weight-average molecular weight is based on a polystyrene standard material as the standard, components with a molecular weight of 200 or higher are included for calculation.

[0033] Preferably, the weight-average molecular weight of the polyurethane and / or polyurethane-urea is in a range of 260,000 to 1,000,000 g / mol. More preferably, the weight-average molecular weight is in a range of 260,000 to 500,000 g / mol. Even more preferably, the weight-average molecular weight is in a range of 260,000 to 400,000 g / mol.

[0034] The aqueous polyurethane dispersion comprises water. Preferably, the aqueous polyurethane dispersion has a solid content of 15 to 70 wt.%.

[0035] More preferably, the aqueous polyurethane dispersion has a solid content of 30 to 65 wt.%.

[0036] Even more preferably, the aqueous polyurethane dispersion has a solid content of 40 to 60 wt.%.

[0037] The solid content can be determined using an HS153 moisture analyzer from Mettler Toledo in accordance with DIN-EN ISO 3251 :2019, at a heating temperature of 120 °C. When the weight loss of the sample is less than 1 mg / 140 seconds, the test endpoint is determined.

[0038] Preferably, the pH value of the aqueous polyurethane dispersion is in a range of 4 to 11.

[0039] More preferably, the pH value of the aqueous polyurethane dispersion is in a range of 5 to 10.

[0040] The pH value can be determined using a PB-10 pH meter from the German company Sartorius. 2024PF30080-Foreign Countries

[0041] - 5 -

[0042] Preferably, the average particle size of the aqueous polyurethane dispersion is in a range of 20 to 750 nm.

[0043] More preferably, the average particle size of the aqueous polyurethane dispersion is in a range of 50 to 450 nm.

[0044] Even more preferably, the average particle size of the aqueous polyurethane dispersion is in a range of 100 to 300 nm.

[0045] Most preferably, the average particle size of the aqueous polyurethane dispersion is in a range of 150 to 250 nm.

[0046] The average particle size is determined using a ZEN 1600 tester through laser correlation (a laser particle size analyzer) from the British company Malvern. In accordance with the ISO 13321 : 1996 test method, one drop (approximately 0.05 g) of a sample is added to 50 ml of ultrapure water, and the diluted sample is tested at a temperature of 23.0 ± 0.1 °C. The refractive index (RI) is measured at 1.590. The absorbance rate is 0.010. Water is selected as the dispersing medium (temperature: 23.0 °C; viscosity: 0.9308 cP; RI: 0.330). The equilibrium time set to 60 seconds, a disposable cuvette DTS0012 is used. The positioning method employed is automatic attenuation selection, searching for the optimal position. The analysis model is universal (normal resolution), and the measurement angle is 173° backscattering (default value for NIBS). 3 repeated test is performed for one sample, and 10 measurements taken for each test, with a duration of 10 seconds for each measurement.

[0047] Preferably, the viscosity of the aqueous polyurethane dispersion is in a range of 300 to 6,000 mPa s.

[0048] The viscosity is measured at 23.0 °C using a DV-II+Pro rotational viscometer from Brookfield in accordance with ISO 2555:2018. The rotor type is S62-64, the rotational speed is 30 RPM, and the testing temperature is 23 °C.

[0049] Component a): crystalline polyol

[0050] As used in the present application, the polyol refers to an alcohol compound comprising at least two hydroxyl groups in the molecule.

[0051] As used in the present application, the term “crystalline polyol” refers to that the polyol has a melting enthalpy of not less than 15 J / g.

[0052] The melting enthalpy is obtained from the first heating curve over a temperature range from 20 °C to 100 °C, using differential scanning calorimetry (DSC), according to method A in DIN 65467: 1999, with sample loading 10 to 20 mg and a heating rate of 20 K / min. 2024PF30080-Foreign Countries

[0053] - 6 -

[0054] Preferably, the melting enthalpy of the crystalline polyol is in a range of 25 J / g to 100 J / g.

[0055] The crystalline polyol may be an aliphatic and / or aromatic polyester polyol.

[0056] Preferably, the crystalline polyol used for the preparation of the polyurethane and / or polyurethane-urea is selected from one or more of diols having a numberaverage molecular weight of 62 to 15,000 g / mol and triols having a number-average molecular weight of 92 to 15,000 g / mol.

[0057] More preferably, the crystalline polyol is selected from one or more of diols having a number-average molecular weight of 62 to 5,000 g / mol and triols having a number-average molecular weight of 92 to 5,000 g / mol.

[0058] Most preferably, the crystalline polyol is selected from one or more polyester polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 500 to 2,500 g / mol, polycarbonate polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 400 to 2,500 g / mol, polyether polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 200 to 2,500 g / mol, and polylactone polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 250 to 2,500 g / mol.

[0059] The number-average molecular weight in the present application is measured using GPC, employing tetrahydrofuran as the mobile phase with a differential refractive detector, and the molecular weight is calculated based on polystyrene as the standard material, components with a molecular weight of 200 or higher is included for calculation.

[0060] The polyester polyol is preferably one or more of the following: a linear polyester polyol, a lightly branched polyester polyol, and a homopolymer or a mixed polymer of a lactone. The linear polyester polyol or the lightly branched polyester polyol is prepared by including the following components: aliphatic, alicyclic or aromatic di- or poly- carboxylic acids, for example succinic acid, methyl succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonane dicarboxylic acid, decane dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexane dicarboxylic acid, maleic acid, fumaric acid, malonic acid or trimellitic acid; acid anhydride, for example phthalic anhydride, trimellitic anhydride or succinic anhydride or a mixture thereof; and low molecular weight polyol, and optinally higher functionality polyol, for example, trimethylolpropane, glycerol or pentaerythritol, alicyclic and / or aromatic di- and poly-hydroxyl compounds. 2024PF30080-Foreign Countries

[0061] - 7 -

[0062] The homopolymer or the mixed polymer of a lactone is preferably obtained by adding the lactone or the lactone mixture such as butyrolactone, e-caprolactone and / or methyl-e- cap rolactone to an appropriate di- and / or higher functional initiator molecule. The e- caprolactone preferably is a polymer of e-caprolactone.

[0063] The polyester polyol preferably is 1,4-butanediol polyadipate diol.

[0064] Advantageously, the amount of the crystalline polyol is 50 to 97 wt.%, preferably 60 to 95 wt.%, more preferably 70 to 93 wt.% of the solid content of the aqueous polyurethane dispersion.

[0065] Component b): polyisocyanate

[0066] The polyisocyanate used for the preparation of polyurethane and / or polyurethaneurea may be an organic compound comprising at least two isocyanate groups.

[0067] Preferably, the polyisocyanate is selected from diisocyanates represented by the formula Y(NCO)2, wherein Y represents a divalent aliphatic hydrocarbon group having 4 to 12 carbon atoms, a divalent alicyclic hydrocarbon group having 6 to 15 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms or a divalent araliphatic hydrocarbon group having 7 to 15 carbon atoms.

[0068] As examples of the polyisocyanate, mention may be made of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexylpropane diisocyanate, 1,4-benzene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, tetramethyl dimethylphenylene diisocyanate, and p-phenylene dimethyl diisocyanate.

[0069] More preferably, the polyisocyanate is selected from diisocyanates represented by the formula Y(NCO)2, wherein Y represents a divalent aliphatic hydrocarbon group having 4 to 12 carbon atoms or a divalent alicyclic hydrocarbon group having 6 to 15 carbon atoms.

[0070] Even more preferably, the polyisocyanate is selected from tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and 4,4'-dicyclohexylpropane diisocyanate.

[0071] Most preferably, the polyisocyanate is a mixture of hexamethylene diisocyanate and isophorone diisocyanate. 2024PF30080-Foreign Countries

[0072] - 8 -

[0073] Advantageously, the amount of the polyisocyanate is 2 to 80 wt.%, preferably 4 to 60 wt.%, more preferably 5 to 40 wt.% of the solid content of the aqueous polyurethane dispersion.

[0074] Component c): hydrophilic compound

[0075] The hydrophilic compound comprises NCO reactive functional groups, and the hydrophilic groups of the hydrophilic compound comprise one or more of ionic groups, potentially ionic groups and nonionic groups,

[0076] The hydrophilic compound used in the present application is different from component a) crystalline polyol.

[0077] In particular, the hydrophilic groups of the hydrophilic compound may be sulfonium, ammonium, phosphine, carboxylate, sulfonate or phosphonate groups, or groups (potentially ionic groups) that can be converted into the above groups by salification, or polyether groups, and may be covalently linked to a polymer chain through isocyanate reactive groups.

[0078] The salification can be carried out by the addition of an organic base (e.g. a tertiary amine) or an inorganic base (e.g. an alkali metal hydroxide or ammonia). Preferably, an aqueous solution of N-(2-aminoethyl)-2-aminoethane sulfonate, or an aqueous solution of dimethylolpropionate or (N-(2-aminoethyl)-2-aminoethane carboxylate (e.g. KV 1386) is used.

[0079] The NCO reactive functional groups of the hydrophilic compound are preferably hydroxyl and / or amino groups.

[0080] In some embodiments, the hydrophilic compound is an ionic or potentially ionic compound.

[0081] Examples of suitable ionic or potentially ionic compounds include mono- and dihydroxycarboxylic acid, dihydroxydicarboxylic acid, mono- and diaminocarboxylic acid, mono- and dihydroxysulfonic acid, mono- and diaminosulfonic acid, mono- and dihydroxyphosphonic acid or mono- and diaminophosphonic acid and the salt thereof, such as dihydroxymethyl propionic acid, dihydroxymethyl butanoic acid, hydroxyneopentanoic acid, N-(2-aminoethyl)alanine, 2-(2-amino-ethylamino) ethanesulfonic acid, ethylenediamine propyl- or butylsulfonic acid, 1,2- or -1,3- propanediamine ethanesulfonic acid, malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3,5-diaminobenzoic acid, an adduct of IPDI and acrylic acid (EP -A 0916647, Example 1) and the alkali metal salt and / or ammonium salt thereof, an adduct of sodium bisulfite on butene-2-diol-l,4, polyether sulfonate, a propoxylated adduct of 2-butenediol and NaHSCE (e.g. Formulae I-III as described in 2024PF30080-Foreign Countries

[0082] - 9 -

[0083] DE-A 2 446 440), and structural units that can be converted into cationic groups, such as N-methyl-diethanolamine. In addition, the salt of cyclohexylamino propanesulfonic acid (CAPS) from WO-A 01 / 88006 can be used as an anionic hydrophilic compound.

[0084] Preferred ionic or potentially ionic compounds are those having a carboxyl or carboxylate and / or sulfonate group and / or an amino group.

[0085] Preferably, the hydrophilic compound is selected from 6-aminohexanoate, lysinate, N-(2-aminoethyl)-P-alaninate, 2-[(2-aminoethyl)amino]ethanesulfonate and 3 -(cyclohexylamino)- 1 -propanesulfonate.

[0086] More preferably, the hydrophilic compound is selected from 2-[(2- aminoethyl)amino]ethanesulfonate and 3 -(cyclohexylamino)- 1 -propanesulfonate.

[0087] Most preferably, the hydrophilic compound is selected from sodium 2-[(2- aminoethyl)amino]ethanesulfonate and sodium 3 -(cyclohexylamino)- 1- propanesulfonate.

[0088] Advantageously, the amount of the hydrophilic compound is 0.1 to 45 wt.%, preferably 0.2 to 30 wt.%, more preferably 0.3 to 10 wt.% of the solid content of the aqueous polyurethane dispersion.

[0089] Component d) small molecule alcohol

[0090] In some embodiments, the system for preparing polyurethane and / or polyurethane-urea comprises component d).

[0091] As examples of the small molecular alcohols, mention may be made of ethanol, propanol, 2-propanol, n-butanol, sec-butanol, n-hexanol and the isomers thereof, 2- ethylhexanol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, di ethylene glycol monobutyl ether, 1,2-propanediol monomethyl ether, 1,3-propanediol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, 1 -octanol, 1 -dodecanol, 1 -cetyl alcohol, lauryl alcohol and stearyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3 -propylene glycol, 1,4-butylene glycol, 1,3- butanediol, 2,3-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-l,3- propanediol, 1,4-dihydroxymethyl cyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cy cl ohexanedi ethanol, 1,4-, 1,3-, 1,2-dihydroxybenzene or 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 2024PF30080-Foreign Countries

[0092] - 10 - tricyclodecane dimethanol, trimethylolpropane, glycerol, pentaerythritol, dipentanetriol or a mixture of at least two of the above.

[0093] Preferably, the small molecule alcohol is selected from 1,4-butylene glycol, 1,6- hexanediol and neopentyl glycol.

[0094] Advantageously, the amount of the small molecule alcohol is 0 to 5 wt.%, preferably 0 to 3 wt.%, more preferably 0 to 1 wt.% of the solid content of the aqueous polyurethane dispersion.

[0095] Component e): additional isocyanate reactive compounds

[0096] In some embodiments, the system for preparing polyurethane and / or polyurethane-urea comprises component e).

[0097] The additional isocyanate reactive compounds in the present application refer to compounds that can react with isocyanate groups other than components a), c) and d). They are selected from amine chain extenders and amine chain terminating agents.

[0098] For example, the additional isocyanate reactive compound may be water, hydrazine, hydrazide, aliphatic or alicyclic monoamines, diamines or triamines, hydroxy functional monoamines or diamines.

[0099] Preferably, the additional isocyanate reactive compound is selected from ethylenediamine, isophorone diamine, diethylenetriamine, ethanolamine, N- methylethanolamine, diethanolamine, diisopropanolamine, 1, 3 -diamino-2 -propanol, N-(2 -hydroxy ethyl)-ethylenediamine, N,N-bis(2 -hydroxy ethyl)-ethylene diamine and 2-propanolamine.

[0100] More preferably, the additional isocyanate reactive compound is selected from isophorone diamine, N-(2-hydroxyethyl)-ethylidenediamine and diethanolamine.

[0101] Advantageously, the amount of the additional isocyanate reactive compound is 0.1 to 10 wt.%, preferably 0.3 to 8 wt.%, more preferably 0.5 to 5 wt.% of the solid content of the aqueous polyurethane dispersion.

[0102] Component (ii): aliphatic alcohol ester

[0103] The aliphatic alcohol ester in the aqueous polyurethane dispersion is a reaction product of one or more aliphatic diols and one or more C2-C18 monocarboxylic acids.

[0104] Preferably, the aliphatic alcohol ester is not crystalline.

[0105] As examples of the aliphatic diols, mention may be made of ethylene glycol, 1,2- propanediol, 1,3 -propanediol, butylene glycol, pentanediol, hexanediol, heptanediol, 2024PF30080-Foreign Countries

[0106] - 11 - octanediol, 2-methylbutanediol, 2-methylpentanediol, 2,2,4-trimethyl-l,3-pentanediol and the like.

[0107] The one or more hydrogen atoms on the aliphatic diols are optionally substituted with an amino group, a nitro group or a halogen (e.g. fluorine, chlorine, bromine or iodine).

[0108] The aliphatic diol is preferably selected from linear or branched C2-C12 diols, more preferably selected from linear or branched C4-C10 diols, most preferably selected from branched C4-C10 diols.

[0109] As examples of the C2-C18 monocarboxylic acids, mention may be made of acetic acid, propionic acid, butyric acid, valeric acid, caprylic acid, isopropionic acid, isobutyric acid, isovaleric acid and the like.

[0110] The aliphatic monocarboxylic acid is preferably selected from linear or branched C2-C14 monocarboxylic acids, more preferably selected from linear or branched C3- C10 monocarboxylic acids, most preferably selected from branched C3-C8 monocarboxylic acids.

[0111] Preferably, the aliphatic alcohol ester is a reaction product of an aliphatic diol selected from branched C4-C10 diols and one or more monocarboxylic acids selected from branched C3-C8 monocarboxylic acids.

[0112] Most preferably, the aliphatic alcohol ester is selected from alcohol ester-12 (i.e., 2,2,4-trimethyl-l,3-pentanediol monoisobutyrate) and alcohol ester-16 (i.e., 2,2,4- trimethyl-l,3-pentanediol diisobutyrate).

[0113] Advantageously, the amount of the aliphatic alcohol ester is 1 to 8 wt.%, preferably 1 to 4 wt.%, more preferably 1 to 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0114] Other Components

[0115] The aqueous polyurethane dispersion of the present invention may also comprise one or more other components that are typically added to aqueous polyurethane dispersions, for example, solvents, preservatives, external emulsifiers, crosslinkers, etc.

[0116] A person of ordinary skill in the art may adjust the amounts of these other components as needed, so that the aqueous polyurethane dispersion of the present invention is not significantly and adversely affected. 2024PF30080-Foreign Countries

[0117] - 12 -

[0118] Preparation of Aqueous Polyurehtane Dispersion

[0119] The aqueous polyurehtane dispersion of the present invention can be prepared by methods commonly used in the art, such as emulsification and dispersion, prepolymer mixing, acetone process, melt emulsification, ketoimide solid phase dispersion and relevant derivative methods thereof.

[0120] For example, the aqueous polyurethane dispersion of the present invention can be prepared by a method comprising the steps of:

[0121] (A) reacting components a), b) and d) at 60 to 120 °C to form an isocyanate- terminated prepolymer, and using acetone for dissolution;

[0122] (B) reacting the prepolymer with component c) and optional e) at 20 to 60 °C;

[0123] (C) adding distilled water for dispersion and emulsification;

[0124] (D) removing the solvent acetone by vacuum, and then adding component (ii) and optional other components to obtain an aqueous polyurethane dispersion.

[0125] The aqueous polyurethane dispersion of the present invention is capable of maintaining stability of a dispersion emulsion under conditions of lower temperatures (e.g. 5 °C). For example, the viscosity variation rate is less than 300% after storage at the temperature of 5 °C for 4 weeks. This greatly reduces the risk of quality issues during transportation, storage and use under low temperatures.

[0126] In addition, the aqueous polyurethane dispersion of the present invention has good initial heat resistance. In the present application, the thermal stability of the aqueous polyurethane dispersion is characterized by the initial heat resistance of an adhesive comprising the aqueous polyurethane dispersion. Good initial heat resistance can ensure that sufficient heat resistance can still be maintained even under conditions of bonding and lamination at elevated ambient temperatures, making it unlikely to have such issues as peeling and delamination.

[0127] Application of Aqueous Polyurethane Dispersion

[0128] The aqueous polyurethane dispersion of the present invention can be used for preparing coatings, adhesives, sealants and inks.

[0129] According to the second aspect of the present invention, there is provided a coating, an adhesive, a sealant or an ink prepared using the above aqueous polyurethane dispersion.

[0130] The coating, adhesive, sealant or ink may further comprise one or more additives selected from: an emulsifier, a light stabilizer, an antioxidant, a bactericide, a filler, an anti-settling agent, an antifoaming agent, a wetting agent, a flow modifier, a reactive 2024PF30080-Foreign Countries

[0131] - 13 - diluent, a plasticizer, a neutralizer, a catalyst, an auxiliary solvent, a thickener, a pigment, a dye, a matting agent, a crosslinker, and a tackifier.

[0132] The crosslinker can be, for example, polyisocyanates, carbodiimides or aziridines.

[0133] The amounts of the additives may be adjusted as needed.

[0134] In some embodiments, the present invention provides an adhesive, comprising the aqueous polyurethane dispersion and a thickener, wherein the thickener accounts for 0.5 to 2.0 wt.% based on the total weight of the adhesive.

[0135] According to a third aspect of the present invention, there is provided use of the coating, adhesive, sealant or ink mentioned above for preparing a coated product, an adhesive product, a sealed product or a printed product.

[0136] Preferably, the coated product, adhesive product, sealed product or printed product is thermally activated.

[0137] According to a fourth aspect of the present invention, there is provided an article comprising a substrate coated, bonded, sealed or printed with said coating, adhesive, sealant or ink.

[0138] Preferably, the article is thermally activated.

[0139] The substrate may be, for example, a rubber, plastic, paper, cardboard, wood, textile, metal, alloy, fabric, fiber, artificial leather, leather, inorganic material, human or animal hair and human or animal skin.

[0140] The article can be prepared by applying the aqueous polyurethane dispersion to the substrate by brushing, dipping, spraying, roller coating, blade coating, flow coating, pouring, printing or transfer printing, preferably by brushing, dipping or spraying, followed by drying, heating activating and bonding.

[0141] The description of various features in the present application may be combined where there is no contradiction, all of which fall within the scope of protection in the present application.

[0142] The expression “and / or” in the present application refers to one or all of the elements mentioned.

[0143] All percentages in the present application are by weight, unless otherwise specified.

[0144] The analytical measurements as described in the present application are all performed at 23±2 °C, unless otherwise specified. 2024PF30080-Foreign Countries

[0145] - 14 -

[0146] The expressions “comprising” and “including” as described in the present application cover the circumstances further comprising or including other elements not specifically mentioned and the circumstances consisting of the elements mentioned.

[0147] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the field the present invention belongs to. When the definition of a term in the present description conflicts with the meaning as commonly understood by a person of ordinary skill in the field the present invention belongs to, the definition described herein shall prevail.

[0148] Unless otherwise specified, all numerical values expressing the amounts of components, reaction conditions and the like in the description and claims should be understood as being modified by the term “about”. Therefore, unless indicated to the contrary, the numerical values described herein are approximate values subject to variations according to the desired performance.

[0149] Examples

[0150] The conception of the present invention, the specific structure and the resulting technical effects will be further illustrated hereinafter in conjunction with the Examples, so that a person of ordinary skill in the art can fully understand the objectives, features and effects of the present invention. It is not difficult for a person of ordinary skill in the art to understand that the Examples herein are for the purpose of illustration only, and the scope of the present invention is not limited thereto.

[0151] Main Raw Materials

[0152] The main raw materials used in the following Examples are as follows. Unless otherwise specified, all the chemical reagents used are analytically pure.

[0153] Polyester I : Difunctional polyester polyol based on adipic acid and 1,4-butanediol, having a number-average molecular weight Mn of 2,250 g / mol, a hydroxyl value of 50 mg KOH / g, a glass transition temperature of -61 °C, a melting temperature of 49 °C, and a melting enthalpy of 80 J / g.

[0154] Isocyanate 1: Hexamethylene diisocyanate (Desmodur® H, Covestro Deutschland AG).

[0155] Isocyanate 2: Isophorone diisocyanate (Desmodur® I, Covestro Deutschland AG).

[0156] Hydrophilic chain extender: Aqueous solution of sodium N-(2-aminoethyl)-2- aminoethane sulfonate at a concentration of 49.5 wt.%, commercially available as VESTAMIN® A 95 from Evonik Chemical Company. 2024PF30080-Foreign Countries

[0157] - 15 -

[0158] Texanol: Alcohol ester-12, commercially available from Eastman Chemical Company.

[0159] TXIB: Alcohol ester- 16, commercially available from Eastman Chemical Company.

[0160] DINP: Diisononyl phthalate, commercially available from Sinopharm Chemical Reagent Co., Ltd.

[0161] Benzoflex 50: Benzoate plasticizer, commercially available from Eastman Chemical Company.

[0162] DMM: Dipropylene glycol dimethyl ether, commercially available from Dow Chemical Company.

[0163] DPM: Dipropylene glycol monomethyl ether, commercially available from Dow Chemical Company.

[0164] PMA: Propylene glycol methyl ether acetate, commercially available from Dow Chemical Company.

[0165] Glycerol: Freeze-thaw stabilizer, commercially available from Sinopharm Chemical Reagent Co., Ltd.

[0166] TERGITOL FT 893: Freeze-thaw stabilizer, commercially available from Dow Chemical Company.

[0167] Borchigel L75N: Polyurethane associative thickener, commercially available from Borchers.

[0168] Testing Methods Used

[0169] The isocyanate (NCO) content was determined by volume in accordance with DIN- EN ISO 11909: 2007.

[0170] The viscosity of the aqueous polyurethane dispersion was measured at 23 °C using aDV-II+Pro rotational viscometer from Brookfield in accordance with ISO 2555:2018. The rotor type was S62-64, the rotational speed was 30 RPM, and the testing temperature was 23 °C.

[0171] The initial heat resistance test was conducted as follows:

[0172] A PVC leather (with an overall size of 2.5 cm*20 cm; the glued and laminated area is 2.5 cm* 10 cm) and an ABS sheet (with an overall size of 2.5 cm* 12.5 cm; the glued and laminated area is 2.5 cm* 10 cm) were used as test substrate. The ABS sheet was wiped with ethanol prior to lamination. 2024PF30080-Foreign Countries

[0173] - 16 -

[0174] The surfaces of the PVC leather and ABS were coated with an adhesive using a 100 pm wire-wound rod, and then placed in an oven at 50 °C to dry for 10 min. After drying, they were left at room temperature for 1 h, then put in the oven again at 60 °C for 10 min for activation. The activated sample was taken out of the oven, manually positioned, and laminated by rolling back and forth once with a 4.5 kg roller. Immediately after lamination, it was placed in the oven at 80 °C, and a 100 g weight was applied, with the weight positioned at angle close to 180 degrees relative to the sample. The peeling time of the sample was recorded. The longer the peeling time, the better the initial heat resistance of the adhesive. In the present application, when the time required for the weight to fall off (peeling 10 cm) exceeds 60 min, it is considered as qualified.

[0175] Other testing methods have been described in other parts of the description or belong to common methods in the art.

[0176] Inventive Example 1 (IE 1)

[0177] 450 g of polyester I was dehydrated at 110 °C and 100 mbar for 1 h, then 2.0 g of 1,4-butanediol was added, followed by cooling while stirring. 40.3 g of isocyanate 1 and 14.9 g of isocyanate 2 were added at 60 °C, and stirred at 80 to 90 °C until an isocyanate content of 1.6% was reached to obtain a reactant comprising a prepolymer. The reactant was subsequently dissolved in 760 g of acetone and cooled to 40 °C to obtain an acetone solution with the prepolymer dissolved therein. 11.1 g of an aqueous solution of sodium N-(2-aminoethyl)aminoethane sulfonate and 30 g of an aqueous solution containing 1.1 g of diethanolamine and 1.3 g of hydroxyethyl ethylenediamine were added to the acetone solution with the prepolymer dissolved therein while stirring vigorously. After stirring for 30 min, the mixture was then dispersed by adding 489 g of water. Following the separation of acetone by distillation (the material at this moment was called material A, with a solid content of 50 wt.%), an aliphatic alcohol ester Texanol was added (wherein the weight ratio of the aliphatic alcohol ester Texanol to the material A was 0.8: 100) to obtain an aqueous polyurethane dispersion having a pH of 7.0 and a particle size of 175 nm, wherein the amount of the aliphatic alcohol ester Texanol was 1.6 wt.% of the solid content of the aqueous polyurethane dispersion.

[0178] Upon testing, it was found that the resulting polyurethane and / or polyurethane-urea had a weight-average molecular weight of 291,000 g / mol, and a melting enthalpy of 37.79 J / g.

[0179] The resulting aqueous polyurethane dispersion and Borchigel L75N at a concentration of 25 wt.% were stirred and mixed to obtain an adhesive. The amount of Borchigel L75N was adjusted (in a range of 0.5 to 2.0 wt.% relative to the total amount of the adhesive) so that the viscosity of the adhesive was about 5,000 mPa- s. 2024PF30080-Foreign Countries

[0180] - 17 -

[0181] Inventive Example 2 (IE 2)

[0182] Inventive Example 2 was carried out with reference to Inventive Example 1, except that the weight ratio of the aliphatic alcohol ester Texanol to the material A was 1 : 100, wherein the amount of the aliphatic alcohol ester Texanol was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0183] Inventive Example 3 (IE 3)

[0184] Inventive Example 3 was carried out with reference to Inventive Example 1, except that the weight ratio of the aliphatic alcohol ester Texanol to the material A was 1.5: 100, wherein the amount of the aliphatic alcohol ester Texanol was 3 wt.% of the solid content of the aqueous polyurethane dispersion.

[0185] Inventive Example 4 (IE 4)

[0186] Inventive Example 4 was carried out with reference to Inventive Example 1, except that the weight ratio of the aliphatic alcohol ester Texanol to the material A was 2: 100, wherein the amount of the aliphatic alcohol ester Texanol was 4 wt.% of the solid content of the aqueous polyurethane dispersion.

[0187] Inventive Example 5 (IE 5)

[0188] Inventive Example 5 was carried out with reference to Inventive Example 1, except that the weight ratio of the aliphatic alcohol ester Texanol to the material A was 4: 100, wherein the amount of the aliphatic alcohol ester Texanol was 8 wt.% of the solid content of the aqueous polyurethane dispersion.

[0189] Inventive Example 6 (IE 6)

[0190] Inventive Example 6 was carried out with reference to Inventive Example 1, except that the aliphatic alcohol ester TXIB rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of the aliphatic alcohol ester TXIB to the material A was 0.5: 100, wherein the amount of the aliphatic alcohol ester TXIB was 1 wt.% of the solid content of the aqueous polyurethane dispersion. 2024PF30080-Foreign Countries

[0191] - 18 -

[0192] Inventive Example 7 (IE 7)

[0193] Inventive Example 7 was carried out with reference to Inventive Example 1, except that 1 g of the aliphatic alcohol ester TXIB rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of the aliphatic alcohol ester TXIB to the material A was 1: 100, wherein the amount of the aliphatic alcohol ester TXIB was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0194] Inventive Example 8 (IE 8)

[0195] Inventive Example 8 was carried out with reference to Inventive Example 1, except that 1.5 g of the aliphatic alcohol ester TXIB rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of the aliphatic alcohol ester TXIB to the material A was 1.5: 100, wherein the amount of the aliphatic alcohol ester TXIB was 3 wt.% of the solid content of the aqueous polyurethane dispersion.

[0196] Test Example 1

[0197] The initial viscosity and the viscosity after 4 weeks of storage at 5 °C of the aqueous polyurethane dispersions obtained in Inventive Examples 1-8 were tested, and the viscosity variation rates were determined upon calculation, with the results summarized in Table 1.

[0198] The initial heat resistance of the adhesives comprising the aqueous polyurethane dispersions was tested, with the results summarized in Table 1.

[0199] Table 1

[0200] Material A: The material prior to addition of the aliphatic alcohol ester Texanol in Inventive Example 1. 2024PF30080-Foreign Countries

[0201] - 19 -

[0202] As can be seen from Table 1, the aqueous polyurethane dispersions obtained in Inventive Examples 1-8 exhibited good low-temperature storage stability and initial heat resistance.

[0203] Comparative Example 1 (CE 1)

[0204] Comparative Example 1 was carried out with reference to Inventive Example 1, except that no aliphatic alcohol ester Texanol was added.

[0205] Comparative Example 2 (CE 2)

[0206] Comparative Example 2 was carried out with reference to Inventive Example 1, except that the weight ratio of the aliphatic alcohol ester Texanol to the material A was 0.4: 100, wherein the amount of the aliphatic alcohol ester Texanol was 0.8 wt.% of the solid content of the aqueous polyurethane dispersion.

[0207] Comparative Example 3 (CE 3)

[0208] Comparative Example 3 was carried out with reference to Inventive Example 1, except that diisononyl phthalate (DINP) rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of diisononyl phthalate (DINP) to the material A was 1 : 100, wherein the amount of diisononyl phthalate (DINP) was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0209] Comparative Example 4 (CE 4)

[0210] Comparative Example 4 was carried out with reference to Inventive Example 1, except that a benzoate plasticizer (Benzoflex 50) rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of the benzoate plasticizer (Benzoflex 50) to the material A was 1: 100, wherein the amount of the benzoate plasticizer (Benzoflex 50) was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0211] Comparative Example 5 (CE 5)

[0212] Comparative Example 5 was carried out with reference to Inventive Example 1, except that dipropylene glycol dimethyl ether (DMM) rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of dipropylene glycol dimethyl ether (DMM) to the material A was 1 : 100, wherein the amount of dipropylene glycol 2024PF30080-Foreign Countries

[0213] - 20 - dimethyl ether (DMM) was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0214] Comparative Example 6 (CE 6)

[0215] Comparative Example 6 was carried out with reference to Inventive Example 1, except that dipropylene glycol monomethyl ether (DPM) rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of dipropylene glycol monomethyl ether (DPM) to the material A was 1 : 100, wherein the amount of di propylene glycol monomethyl ether (DPM) was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0216] Comparative Example 7 (CE 7)

[0217] Comparative Example 7 was carried out with reference to Inventive Example 1, except that propylene glycol methyl ether acetate (PMA) rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of propylene glycol methyl ether acetate (PMA) to the material A was 1: 100, wherein the amount of propylene glycol methyl ether acetate (PMA) was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0218] Comparative Example 8 (CE 8)

[0219] Comparative Example 8 was carried out with reference to Inventive Example 1, except that glycerol rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of glycerol to the material A was 1: 100, wherein the amount of glycerol was 2 wt.% of the solid content of the aqueous polyurethane dispersion.

[0220] Comparative Example 9 (CE 9)

[0221] Comparative Example 9 was carried out with reference to Inventive Example 1, but differed in that a freeze-thaw stabilizer TERGITOL FT 893 rather than the aliphatic alcohol ester Texanol was added, and the weight ratio of the freeze-thaw stabilizer TERGITOL FT 893 to the material A was 1 : 100, wherein the amount of the freezethaw stabilizer TERGITOL FT 893 was 2 wt.% of the solid content of the aqueous polyurethane dispersion. 2024PF30080-Foreign Countries

[0222] - 21 -

[0223] Comparative Example 10 (CE 10)

[0224] 450 g of polyester I was dehydrated at 110 °C and 100 mbar for 1 h, then 0.3 g of 1,4-butanediol was added, followed by cooling while stirring. 40.1 g of isocyanate 1 and 10.1 g of isocyanate 2 were added at 60 °C, and stirred at 80 to 90 °C until an isocyanate content of 1.6% was reached to obtain a reactant comprising a prepolymer. The reactant was subsequently dissolved in 760 g of acetone and cooled to 40 °C to obtain an acetone solution with the prepolymer dissolved therein. 14.4 g of an aqueous solution of sodium N-(2-aminoethyl)aminoethane sulfonate and 30 g of an aqueous solution containing 2.4 g of diethanolamine were added to the acetone solution with the prepolymer dissolved therein while stirring vigorously. After stirring for 30 min, the mixture was then dispersed by adding 490 g of water. Following the separation of acetone by distillation (the material at this moment was called material B, with a solid content of 50 wt.%), an aliphatic alcohol ester Texanol was added (wherein the weight ratio of the aliphatic alcohol ester Texanol to the material B was 0.8: 100) to obtain an aqueous polyurethane dispersion having a pH of 6.9 and a particle size of 190 nm, wherein the amount of the aliphatic alcohol ester Texanol was 1.6 wt.% of the solid content of the aqueous polyurethane dispersion.

[0225] Upon testing, it was found that the resulting polyurethane and / or polyurethane-urea had a weight-average molecular weight of 160,000 g / mol, and a melting enthalpy of 37.69 J / g.

[0226] The resulting aqueous polyurethane-urea dispersion and Borchigel L75N at a concentration of 25 wt.% were stirred and mixed to obtain an adhesive. The amount of Borchigel L75N was adjusted (in a range of 0.5 to 2.0 wt.% relative to the total amount of the adhesive) so that the viscosity of the adhesive was about 5,000 mPa- s.

[0227] 2024PF30080-Foreign Countries

[0228] - 22 -

[0229] Test Example 2

[0230] The initial viscosity and the viscosity after 4 weeks of storage at 5 °C of the aqueous polyurethane dispersions obtained in Comparative Examples 1-10 were tested, and the viscosity variation rates were determined through calculation, with the results summarized in Table 2.

[0231] The initial heat resistance of the adhesives comprising the aqueous polyurethane dispersions was tested, with the results summarized in Table 2.

[0232] Table 2

[0233] Material A: The material prior to addition of the aliphatic alcohol ester Texanol in Inventive Example 1.

[0234] Material B: The material prior to addition of the aliphatic alcohol ester Texanol in Comparative Example 10. n.a.: Untested.

[0235] As can be seen from Table 2, the aqueous polyurethane dispersions obtained in Comparative Examples 1-10 failed to demonstrate both good low-temperature storage stability and initial heat resistance.

[0236] Only exemplary embodiments or examples of the present invention are described above, and they are not intended to limit the present invention. For a person of ordinary skill in the art, the present invention may be modified or changed in various manners. Any modification, equivalent replacement, improvement and the like made without 2024PF30080-Foreign Countries

[0237] - 23 - departing from the spirit and principles of the present invention shall fall within the scope of the claims of the present application.

Claims

1. 2024PF30080-Foreign Countries- 24 -Claims:

1. A aqueous polyurethane dispersion, comprising:(i) polyurethane and / or polyurethane-urea prepared by reaction of a system comprising components a)-c) and optional components d)-e): a) at least one crystalline polyol, b) at least one polyisocyanate, c) at least one hydrophilic compound comprising NCO reactive functional groups, wherein hydrophilic groups of the hydrophilic compound comprise one or more of ionic groups, potentially ionic groups and nonionic groups, d) a small molecule alcohol different from components a) and c), comprising 1 to 4 NCO reactive functional groups and having a molecular weight of 32 to 400 g / mol, e) an additional isocyanate reactive compound, which is one or more of amine chain extenders and amine chain terminating agents, and(ii) at least one aliphatic alcohol ester, which is a reaction product of one or more aliphatic diols and one or more C2-C18 monocarboxylic acids, wherein the amount of the at least one aliphatic alcohol ester is 1 to 8 wt.% of the solid content of the aqueous polyurethane dispersion, and the weight-average molecular weight of the polyurethane and / or polyurethaneurea is 260,000 g / mol or greater, preferably 260,000 to 1,000,000 g / mol, more preferably 260,000 to 500,000 g / mol, and even more preferably 260,000 to 400,000 g / mol.

2. The aqueous polyurethane dispersion according to claim 1, wherein the aqueous polyurethane dispersion has a solid content of 15 to 70 wt.%, preferably 30 to 65 wt.% and more preferably 40 to 60 wt.%.

3. The aqueous polyurethane dispersion according to claim 1 or 2, wherein the crystalline polyol is one or more selected from diols having a number-average molecular weight of 62 to 15,000 g / mol and triols having a number-average molecular weight of 92 to 15,000 g / mol, preferably, the crystalline polyol is one or more selected from diols having a number-average molecular weight of 62 to 5,000 g / mol and triols having a numberaverage molecular weight of 92 to 5,000 g / mol, and2024PF30080-Foreign Countries- 25 - more preferably, the crystalline polyol is one or more selected from polyester polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 500 to 2,500 g / mol, polycarbonate polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 400 to 2,500 g / mol, polyether polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 200 to 2,500 g / mol, and polylactone polyols comprising 1.5 to 3 hydroxyl groups with a number-average molecular weight of 250 to 2,500 g / mol.

4. The aqueous polyurethane dispersion according to any one of claims 1 to 3, wherein the amount of the crystalline polyol is 50 to 97 wt.%, preferably 60 to 95 wt.%, more preferably 70 to 93 wt.% of the solid content of the aqueous polyurethane dispersion.

5. The aqueous polyurethane dispersion according to any one of claims 1 to 4, wherein the polyisocyanate is selected from diisocyanates represented by the formula Y(NCO)2, wherein Y represents a divalent aliphatic hydrocarbon group having 4 to 12 carbon atoms, a divalent alicyclic hydrocarbon group having 6 to 15 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms or a divalent araliphatic hydrocarbon group having 7 to 15 carbon atoms, preferably, Y represents a divalent aliphatic hydrocarbon group having 4 to 12 carbon atoms, or a divalent alicyclic hydrocarbon group having 6 to 15 carbon atoms, and more preferably, the polyisocyanate is selected from tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'- dicyclohexylmethane diisocyanate and 4,4'-dicyclohexylpropane diisocyanate.

6. The aqueous polyurethane dispersion according to any one of claims 1 to 5, wherein the amount of the polyisocyanate is 2 to 80 wt.%, preferably 4 to 60 wt.%, more preferably 5 to 40 wt.% of the solid content of the aqueous polyurethane dispersion.2024PF30080-Foreign Countries- 26 -7. The aqueous polyurethane dispersion according to any one of claims 1 to 6, wherein the NCO reactive functional groups of the hydrophilic compound are hydroxyl and / or amino groups; preferably, the hydrophilic compound is an ionic or potentially ionic compound, preferably an ionic or potentially ionic compound having a carboxyl or carboxylate and / or sulfonate group and / or an amino group, more preferably selected from 6-aminohexanoate, lysinate, N-(2-aminoethyl)-P-alaninate, 2-[(2-aminoethyl)amino]ethanesulfonate and 3 -(cyclohexylamino)- 1- propanesulfonate, even more preferably selected from 2-[(2- aminoethyl)amino]ethanesulfonate and 3 -(cyclohexylamino)- 1 -propanesulfonate, and most preferably selected from sodium 2-[(2-aminoethyl)amino]ethanesulfonate and sodium 3 -(cyclohexylamino)- 1 -propanesulfonate.

8. The aqueous polyurethane dispersion according to any one of claims 1 to 7, wherein the amount of the hydrophilic compound is 0.1 to 45 wt.%, preferably 0.2 to 30 wt.%, more preferably 0.3 to 10 wt.% of the solid content of the aqueous polyurethane dispersion.

9. The aqueous polyurethane dispersion according to any one of claims 1 to 8, wherein the reaction system comprises component d) a small molecule alcohol; preferably, the small molecule alcohol is selected from ethanol, propanol, 2-propanol, n-butanol, sec-butanol, n-hexanol and the isomers thereof, 2-ethylhexanol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, 1 -octanol, 1 -dodecanol, 1 -cetyl alcohol, lauryl alcohol and stearyl alcohol, ethylene glycol, di ethylene glycol, tri ethylene glycol, tetraethylene glycol, 1,2-propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3 -propylene glycol, 1,4-butylene glycol,1.3 -butanediol, 2,3-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1.3-propanediol, 1,4-dihydroxymethyl cyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cy cl ohexanedi ethanol,1.4-, 1,3-, 1,2-dihydroxybenzene or 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), tricyclodecane dimethanol, trimethylolpropane, glycerol, pentaerythritol, dipentanetriol or a mixture of at least two of the above.2024PF30080-Foreign Countries- 27 -10. The aqueous polyurethane dispersion according to any one of claims 1 to 9, wherein the amount of the small molecule alcohol is 0 to 5 wt.%, preferably 0 to 3 wt.%, more preferably 0 to 1 wt.% of the solid content of the aqueous polyurethane dispersion.

11. The aqueous polyurethane dispersion according to any one of claims 1 to 10, wherein the reaction system comprises component e) an additional isocyanate reactive compound; preferably, the additional isocyanate reactive compound is selected from ethylenediamine, isophorone diamine, diethylenetriamine, ethanolamine, N- methylethanolamine, diethanolamine, diisopropanolamine, 1, 3 -diamino-2 -propanol, N-(2 -hydroxy ethyl)-ethylenediamine, N,N-bis(2 -hydroxy ethyl)-ethylene diamine and 2-propanolamine; more preferably, the additional isocyanate reactive compound is selected from isophorone diamine, N-(2-hydroxyethyl)-ethylenediamine and diethanolamine.

12. The aqueous polyurethane dispersion according to any one of claims 1 to 11, wherein the amount of the additional isocyanate reactive compound is 0.1 to 10 wt.%, preferably 0.3 to 8 wt.%, more preferably 0.5 to 5 wt.% of the solid content of the aqueous polyurethane dispersion.

13. The aqueous polyurethane dispersion according to any one of claims 1 to 12, wherein the aliphatic diol for preparing the aliphatic alcohol ester is selected from linear or branched C2-C12 diols, more preferably selected from linear or branched C4- C10 diols, most preferably selected from branched C4-C10 diols; the monocarboxylic acid for preparing the aliphatic alcohol ester is selected from linear or branched C2-C14 monocarboxylic acids, more preferably selected from linear or branched C3-C10 monocarboxylic acids, most preferably selected from branched C3-C8 monocarboxylic acids; preferably, the aliphatic alcohol ester is a reaction product of one or more aliphatic diols selected from branched C4-C10 diols and one or more monocarboxylic acids selected from branched C3-C8 monocarboxylic acids, more preferably selected from alcohol ester-12 and alcohol ester-16.

14. A coating, an adhesive, a sealant or an ink, prepared using the aqueous polyurethane dispersion according to any one of claims 1 to 13.

15. An article, comprising a substrate coated, bonded, sealed or printed with the coating, adhesive, sealant or ink according to claim 14.

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