Water dispersible polyurethane

Abstract

The present invention relates to an aqueous dispersion comprising dispersed particles, wherein the dispersed particles comprise a polyurethane, wherein the polyurethane comprises structural units derived from at least a) at least one organic polyisocyanate, b) at least one isocyanate-reactive compound bearing a carboxylate group, and c) at least one organic isocyanate-reactive polyol, wherein at least one of the compounds b) bearing a carboxylate group has the following structural formula: II(1) R2(R3)-N-C-R1-COO ‑ , wherein R1 is a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms, or a divalent cycloaliphatic hydrocarbon group having 6 to 8 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 8 carbon atoms, and R2 and R3 are 2-hydroxypropyl.

Description

[0001] The present invention relates to an aqueous dispersion comprising dispersed particles of a specific water-dispersible polymer containing a urethane bond, a coating composition thereof, and a coating obtained by using the coating composition.

[0002] Polyurethane aqueous dispersions and their use in coatings are well known in the art. It is well known in the coatings industry that polyurethane binders can be applied to a variety of substrates to provide coatings with good mechanical and chemical resistance.

[0003] Water-dispersible polyurethanes are prepared using at least one organic polyisocyanate, at least one organic polyol and compounds designed to provide stability to dispersions in water. To increase molecular weight, they are often chain extended after dispersion in water. The chain extension can be achieved by reacting the terminal isocyanate groups of an isocyanate-terminated polyurethane prepolymer with water, or by adding a diamine to the initial dispersion that will react with the isocyanate groups faster than water. A very common compound designed to provide stability to dispersions in water is 2,2-dimethylolpropionic acid, which is used as an ionic precursor; the carboxylic acid groups are neutralized with, for example, ammonia to impart dispersibility. See, for example, US9,074,038B2 and US9,790,317B2. 2,2-Dimethylolpropionic acid is a potentially ionic monomer having a carboxylic acid group and two hydroxyl groups reactive toward isocyanate groups, and has the following structural formula:

[0004]

[0005] The carboxylic acid groups represent "potentially ionic" groups, whereas the salt groups obtained by neutralizing the carboxylic acid groups to carboxylate groups are "ionic" groups. Conversion of any potentially ionic water-dispersing groups present in the prepolymer to ionic water-dispersing groups can be obtained by neutralization before, after or simultaneously with formation of the aqueous prepolymer dispersion.

[0006] A disadvantage of using 2,2-dimethylolpropionic acid is that relatively high amounts are required to prepare stable dispersions, leading to a relatively high acid number of the resulting high content of salt groups, i.e., carboxylate groups, of the polyurethane. Polyurethanes with high acid numbers tend to produce materials that are completely soluble in water or to produce particles of very small particle size, both of which lead to increased viscosity of the dispersion. In turn, relatively high levels of acid groups in polyurethanes tend to make coatings made therefrom inherently more sensitive to water, less hydrolytically stable, and therefore less durable.

[0007] It is therefore advantageous to employ lower acid numbers in the polyurethane, but certainly not at the expense of the effectiveness of the water dispersibility and stability of the aqueous dispersion.

[0008] It is an object of the present invention to provide a water-dispersible polyurethane which can have a relatively low acid number without at the same time negatively affecting the stability of the aqueous dispersion of the polyurethane.

[0009] According to the present invention, there is provided a water-dispersible polyurethane comprising at least the following structural units derived from:

[0010] a) at least one organic polyisocyanate,

[0011] b) at least one isocyanate-reactive compound bearing organic carboxylate groups for providing chain-pendant carboxylate ion dispersing groups in the polyurethane, and

[0012] c) at least one organic isocyanate-reactive polyol,

[0013] At least one of the compounds b) having a carboxylate group has the following structural formula

[0014]

[0015] in

[0016] R1 is a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms, preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms, or a divalent cycloaliphatic hydrocarbon group having 6 to 8 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 8 carbon atoms,

[0017] R2 and R3 are both 2-hydroxypropyl. The present invention also relates to an aqueous polyurethane dispersion, wherein the polyurethane comprises structural units derived from a), b) and c) as defined above.

[0018] It has been surprisingly found that amide carboxylic acid compounds of formula (1) can be used to stabilize polyurethanes in water. In addition, it has been surprisingly found that even when using amide carboxylic acid compounds of formula (1) in lower amounts than 2,2-dimethylol propionic acid (DMPA), stabilization can also be achieved, resulting in a lower acid value of the polyurethane, thereby resulting in better water resistance. Compared with DMPA-stabilized polyurethane dispersions, the polyurethanes of the present invention surprisingly also allow dispersions with higher solids content of controlled viscosity. The present invention even allows solids content in the range of +45% by weight, even in the range of +50% by weight, while viscosity remains controllable aqueous dispersions. High viscosity coatings or paint compositions are undesirable because more effort will be required to apply the coatings or paint compositions. Higher solids content coatings or paint compositions are advantageous because they make the coating or painting process less labor-intensive and time-consuming, particularly considering that the previous layer needs to be sufficiently dry before applying the successive layers. Thus, at lower solid contents, the coater must apply, for example, three coats of coating on the substrate instead of two, resulting in higher labor costs and longer drying times. Thus, using the present invention, polyurethanes with low acid values ​​can be obtained, and they allow dispersions with higher solid contents with controlled viscosities. Another advantage of the present invention is that the polyurethanes of the present invention have narrow particle size distributions. Narrow particle size distributions tend to result in better storage stability of aqueous dispersions due to a reduction in the amount of larger particle fractions that are more susceptible to sedimentation. Again, the presence of very small particles or even solubilized polymer fractions will be reduced, thereby reducing the viscosity of the final dispersion.

[0019] US5053317 describes a radiation polymerizable mixture comprising a solvent-based polyurethane containing carboxylate groups and urea groups; in an example, an addition product formed from succinic anhydride and diethanolamine is used as a reactant for preparing the polyurethane to remove the uncured coating area by washing with an aqueous solution. US4686240 relates to a method for preparing water-blown polyurethane foam using certain foam modifiers. In Example 10, an adduct of succinic anhydride and diethanolamine is used as a foam modifier. US4616061 describes an aqueous solution or dispersion of a polyisocyanate addition product, the aqueous solution or dispersion containing a certain amount of incorporated sulfonate and / or carboxylate groups and optional ethylene oxide units to ensure its solubility or dispersibility in water, and the polyisocyanate addition product further contains acylated urea groups formed by reaction of acid groups with intrachain polycarbodiimide groups. These patent publications do not describe aqueous dispersions comprising polyurethane particles comprising pendant carboxylate groups incorporated by reacting an amide carboxylic acid compound as defined in the present invention.

[0020] For all upper and / or lower boundaries of any range given herein, unless otherwise specifically indicated, the boundary values ​​are included in the given range. Thus, when it is said from x to y, it is meant to include x and y and also all intermediate values.

[0021] The term "aliphatic hydrocarbon group" refers to optionally branched alkyl, alkenyl and alkynyl groups. The term "cycloaliphatic hydrocarbon group" refers to cycloalkyl and cycloalkenyl groups optionally substituted by at least one aliphatic hydrocarbon group. The term "aromatic hydrocarbon group" refers to a benzene ring optionally substituted by at least one aliphatic hydrocarbon group. The aliphatic hydrocarbon group is preferably an alkyl group. Examples of alicyclic hydrocarbon groups having 7 carbon atoms are cycloheptyl and methyl-substituted cyclohexyl. Examples of aromatic hydrocarbon groups having 7 carbon atoms are methyl-substituted phenyl. Examples of aromatic hydrocarbon groups having 8 carbon atoms are xylyl and ethyl-substituted phenyl.

[0022] R1 is a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms, preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms, or a divalent cycloaliphatic hydrocarbon group having 6 to 8 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 8 carbon atoms. R1 is preferably an optionally branched C2-C6 alkyl group, an optionally branched C2-C6 alkenyl group, a C6-C8 cycloalkyl group or a C6-C8 cycloalkenyl group.

[0023] R2 and R3 are both 2-hydroxypropyl (CH3-CH(OH)-CH2-).

[0024] Preferably at least 25 wt %, more preferably at least 30 wt %, even more preferably at least 40 wt %, even more preferably at least 50 wt %, even more preferably at least 75 wt %, even more preferably at least 90 wt % and most preferably 100 wt % of component b) is according to formula (1).

[0025] Preferably, the polyurethane is the reaction product of at least

[0026] A) at least one organic polyisocyanate,

[0027] B') at least one isocyanate-reactive compound bearing an organic carboxylic acid, which serves to provide pendant carboxylate ion dispersing groups in the polyurethane,

[0028] C) at least one organic isocyanate-reactive polyol, and

[0029] D) at least one neutralizing agent for neutralizing at least a portion of the carboxylic acid groups,

[0030] At least one of the carboxylic acid-bearing compounds B') has the following structural formula

[0031]

[0032] wherein R1, R2 and R3 are as defined above.

[0033] The present invention also relates to an aqueous polyurethane dispersion, wherein the polyurethane is the reaction product of at least

[0034] A) at least one organic polyisocyanate,

[0035] B') at least one isocyanate-reactive compound bearing an organic carboxylic acid, which serves to provide pendant carboxylate ion dispersing groups in the polyurethane,

[0036] C) at least one organic isocyanate-reactive polyol, and

[0037] D) at least one neutralizing agent for neutralizing at least a portion of the carboxylic acid groups,

[0038] At least one of the carboxylic acid-bearing compounds B') has the following structural formula

[0039]

[0040] wherein R1, R2 and R3 are as defined above.

[0041] The carboxylic acid-bearing compound B') of formula (2) is a diol. More preferably, the carboxylic acid-bearing compound B') of formula (2) is the reaction product of at least diisopropanolamine and a cyclic anhydride. The cyclic anhydride is preferably selected from the group consisting of succinic anhydride, glutaric anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, phthalic anhydride, and any mixture thereof. More preferably, the cyclic anhydride is selected from the group consisting of glutaric anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and any mixture thereof. Most preferably, the cyclic anhydride is glutaric anhydride. Most preferably, the carboxylic acid-bearing diol B') of formula (2) is the reaction product of glutaric anhydride and diisopropanolamine.

[0042] The carboxylic acid-bearing compound B') of formula (2) is preferably obtained by reacting a cyclic anhydride with diisopropanolamine at atmospheric pressure and at a temperature equal to or higher than the melting point of the cyclic anhydride. Typically, the reaction temperature is at most 10°C higher than the melting point of the cyclic anhydride. The carboxylic acid-bearing compound B') can be prepared in situ and preferably is not isolated. For example, a glutaric acid-based diol having the formula

[0043]

[0044] It can be prepared, for example, by mixing a diol solution with diisopropanolamine, heating this mixture to a temperature slightly above the melting point of glutaric anhydride, for example to 60-65° C., to which glutaric anhydride is added. To prepare the polyurethane, the diolamide glutaric acid is then further reacted with at least one organic polyisocyanate (A) and at least one organic isocyanate-reactive polyol (C) to obtain a higher molecular weight prepolymer. Preferably, the higher molecular weight prepolymer thus obtained is neutralized with a neutralizing agent (e.g. triethylamine) to obtain a water-dispersible polyurethane and then mixed with water to obtain an aqueous dispersion of the polyurethane.

[0045] It has surprisingly been found that a smaller amount of carboxylic acid-bearing compound B') is required to stabilize the urethane dispersion than when DMPA is used. Most DMPA-containing polyurethanes have an acid number of 12 or more in order to be stable in water. Using the amic acid diols according to the invention, polyurethanes with an acid number as low as 5 can be obtained, while being stable at room temperature for at least 2 weeks, preferably at least 4 weeks, more preferably at least 8 weeks, and most preferably at 50° C. for at least 4 weeks. Thus, the polyurethanes according to the invention can have a lower acid number than similar polyurethanes internally stabilized by using 2,2-dimethylolpropionic acid, without negatively affecting the stability of the aqueous dispersion of the polymer. When using carboxylic acid-bearing compound B') of formula (2), acid numbers as low as 5 mg KOH / g of polyurethane can be obtained, while when using 2,2-dimethylolpropionic acid, acid numbers of at least about 12 mg KOH / g of polyurethane are required (usually acid numbers between 16 mg KOH / g and 22 mg KOH / g) to prepare a stable dispersion without having to add additional external stabilizers, i.e. surfactants, which is advantageous because surfactants impart water sensitivity to the coating. The acid value of the polyurethane according to the present invention is preferably in the range of 5 mg KOH / g polyurethane to 30 mg KOH / g polyurethane, more preferably in the range of 5.5 mg KOH / g polyurethane to 22 mg KOH / g polyurethane, even more preferably 6 mg KOH / g polyurethane to 16 mg KOH / g polyurethane, most preferably 6 mg KOH / g polyurethane to 14 mg KOH / g polyurethane. As used herein, the acid value is the mass of potassium hydroxide (KOH) in milligrams required to neutralize one gram of solid polymer.

[0046] Furthermore, it has been surprisingly found that the present invention allows obtaining polyurethanes having smaller particle sizes compared to urethane dispersions prepared with DMPA, without having to increase the acid number or even having a lower acid number, while at the same time the viscosity remains controllable. Dispersed particles comprising the polyurethane according to the invention advantageously have a particle size of 15 nm to 1000 nm, more preferably 20 nm to 600 nm, more preferably 50 nm to 400 nm, most preferably 60 nm to 250 nm. In the context of the present invention, the particle size and particle size distribution are measured as described in the experimental part.

[0047] Methods for preparing polyurethanes are known in the art and are described, for example, in Polyurethane Handbook 2. nd Edition, a Carl Hanser publication, 1994, by G. Oertel. The polyurethane can be prepared in a conventional manner by reacting at least A), B') and C) by methods well known in the prior art. Typically, an isocyanate-terminated polyurethane prepolymer is first formed by reacting at least components A), B') and C), the carboxylic acid groups are at least partially converted into salt groups by reaction with a neutralizing agent, and the isocyanate-terminated polyurethane prepolymer (I) is then optionally chain-extended with an active hydrogen-containing compound (II). In a preferred embodiment, the polyurethane according to the invention is the reaction product of at least

[0048] (I) an at least partially neutralized isocyanate-terminated polyurethane prepolymer formed by reacting at least (A), (B'), (C) and (D) with a degree of neutralization of preferably 1.25 to 0.25 stoichiometric amount, more preferably 0.95 to 0.3 stoichiometric amount, most preferably 0.8 to 0.4 stoichiometric amount, and

[0049] (II) an active hydrogen-containing chain-extending compound. The at least partially neutralized isocyanate-terminated prepolymer is obtained by reacting at least (A), (B'), (C) and (D), wherein the neutralizing agent is added in an amount sufficient to neutralize preferably 1.25 to 0.25 stoichiometric amount of the carboxylic acid groups introduced into the prepolymer by the carboxylic acid-bearing compound B'), more preferably 0.95 to 0.3, most preferably 0.8 to 0.4 stoichiometric amount of the carboxylic acid groups.

[0050] In a specific embodiment, the product value of the polyurethane acid value expressed in mg KOH / g (preferably in the range of 5-30 mg KOH / g) and the degree of neutralization expressed in stoichiometric amount (preferably in the range of 1.25 to 0.25) is preferably 3 to 35, more preferably 3.5 to 24, more preferably 4 to 16, most preferably 4 to 12, and particularly preferably 5 to 10. The product value of the polyurethane acid value expressed in mg KOH / g and the degree of neutralization expressed in stoichiometric amount is also referred to herein as the neutralized acid value.

[0051] The polyurethane according to the present invention may further comprise structural units derived from other components in addition to components A), B'), C). The polyurethane according to the present invention optionally further comprises structural units derived from at least one organic isocyanate-reactive monool containing a double bond (component E), such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxy-2,2-dimethylpropyl (meth)acrylate. Preferably, component E) is 2-hydroxyethyl (meth)acrylate. The most preferred component E) is 2-hydroxyethyl methacrylate. Relative to the total amount of components used to prepare the polyurethane (the structural units of the polyurethane are generated from the components), the amount of this other component E) is preferably in the range of 0% by weight to 5% by weight, more preferably 0% by weight to 4% by weight, and even more preferably 0% by weight to 3% by weight. In a particular embodiment, the amount of component E) is in the range of 0.05% to 5% by weight, preferably 0.1% to 4% by weight, even more preferably 0.5% to 3% by weight, relative to the total amount of the components used to prepare the polyurethane from which the structural units of the polyurethane are derived.

[0052] In case the polyurethane according to the invention is the reaction product of components A), B'), C), D), E) and an active hydrogen-containing chain-extending compound (II), the total amount of the components used to prepare the polyurethane (from which the structural units of the polyurethane are derived) refers herein to the total amount of components A), B'), C) and E), thus excluding the amount of the neutralizing agent D) and the amount of the active hydrogen-containing chain-extending compound (II).

[0053] The present invention also relates to a polyurethane which is the reaction product of at least components A), B'), C), D), optionally E) and preferably component II). Components A), B'), C), D), E) and II) and their amounts are as described herein.

[0054] Component A)

[0055] The organic polyisocyanate A) used for preparing the polyurethane according to the invention is a polyisocyanate containing at least two free isocyanate groups. Preferably, the organic polyisocyanate A) comprises at least one diisocyanate Y(NCO)2. Such an organic diisocyanate may be an aliphatic (this term includes cycloaliphatic), araliphatic or aromatic polyisocyanate. Preferably, Y represents a divalent aliphatic hydrocarbon radical having 4 to 10 carbon atoms, more preferably 5 to 9 carbon atoms; a divalent cycloaliphatic hydrocarbon radical having 6 to 13 carbon atoms, more preferably 8 to 13 carbon atoms; a divalent aromatic hydrocarbon radical having 6 to 13 carbon atoms; or a divalent araliphatic hydrocarbon radical having 7 to 15 carbon atoms.

[0056] Examples of suitable aliphatic polyisocyanates include ethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclopentylene diisocyanate, p-tetra-methylxylene diisocyanate (p-TMXDI) and its meta-isomer (m-TMXDI), hydrogenated 2,4-toluene diisocyanate, hydrogenated 2,6-toluene diisocyanate, 1-isocyanato-1-methyl-3(4)-isocyanatomethyl-cyclohexane (1-isocyanato-1-methyl-3(4)-isocyanatomethyl-cyclohexane, IMCI), pentamethylene diisocyanate, and mixtures thereof. Suitable non-aliphatic polyisocyanates include p-xylene diisocyanate, 1-4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate and mixtures thereof. Mixtures of aliphatic polyisocyanates and aromatic polyisocyanates can be used, as can polyisocyanates modified by the introduction of carbamate, allophanate, urea, biuret, carbodiimide, uretonimine or isocyanurate residues.

[0057] The organic polyisocyanate A) is preferably at least one aliphatic diisocyanate. The organic polyisocyanate A) is more preferably selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate (1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane), methylene dicyclohexyl diisocyanate (4,4'-diisocyanato-dicyclohexyl-methane), triisocyanurate of hexamethylene diisocyanate, biuret of hexamethylene diisocyanate, and any mixtures of these compounds.

[0058] The amount of component A) is preferably 10% to 59% by weight, more preferably 15% to 55% by weight, and even more preferably 20% to 50% by weight, relative to the total weight of the components used to prepare the polyurethane (from which the structural units of the polyurethane are derived). As used herein, the structural units of the polyurethane are derived from at least components A), B'), C) and optionally E), but not from the neutralizing agent D) and not from the chain extending compound (II).

[0059] Component B')

[0060] At least a portion of component B') is according to formula (2).

[0061] Component B') may further comprise an isocyanate-reactive compound containing an ionic or potentially ionic water-dispersing group but having a structural formula different from that of formula (2). Preferred ionic water-dispersing groups are anionic water-dispersing groups. Preferred anionic water-dispersing groups are obtained from carboxylic acid, phosphoric acid and / or sulfonic acid groups. Examples of such compounds include carboxyl-containing diols other than compound B') of formula (2), such as dihydroxyalkanoic acids, such as 2,2-dimethylol propionic acid (DMPA) or 2,2-dimethylolbutanoic acid (DMBA). Alternatively, a sulfonate group may be used as an anionic water-dispersing group.

[0062] Preferably at least 25 wt %, more preferably at least 30 wt %, even more preferably at least 40 wt %, even more preferably at least 50 wt %, even more preferably at least 75 wt %, even more preferably at least 90 wt % and most preferably 100 wt % of component B') is according to formula (2).

[0063] Suitable and preferred examples of carboxylic acid-bearing compounds B′) of formula (2) for preparing the polyurethanes according to the invention are described above.

[0064] The amount of component B') is generally 1 to 15% by weight, preferably 2 to 9% by weight and even more preferably 2.5 to 6% by weight, relative to the total weight of the components for preparing the polyurethane from which the structural units of the polyurethane are derived.

[0065] Component C)

[0066] Component C) can be selected from any polyol that can be used for polyurethane synthesis. Component C) is at least one other organic isocyanate reactive polyol other than component B'). Component C) preferably has a number average molecular weight greater than 400 Daltons, more preferably greater than 450 Daltons. The number average molecular weight of component C) is preferably less than or equal to 6000 Daltons, more preferably less than or equal to 3000 Daltons, most preferably less than or equal to 2000 Daltons, and particularly preferably ≤1500 Daltons. As used herein, the number average molecular weight of the hydroxyl-containing component is determined by multiplying the equivalent weight of the component by the OH functionality of the component (the OH functionality of the polyol is given by the supplier; in the case where the polyol is a diol, the OH functionality is 2). The equivalent weight of the component is calculated by dividing 56100 by the OH value of the component. The OH value of the component is measured by titrating a known mass of the component according to ASTM D4274 and is expressed as mg KOH / g.

[0067] In particular, component C) can be a polyester polyol, a polyester amide polyol, a polyether polyol, a polythioether polyol, a polycarbonate polyol, a polyacetal polyol, a polyethylene polyol and / or a polysiloxane polyol. Preferably, component C) comprises at least one polyol selected from the group consisting of polyester (amide) polyols, polyether polyols, polycarbonate polyols and any mixture thereof. More preferably, component C) comprises at least one polyol selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyols and any mixture thereof.

[0068] Component C) may also optionally contain organic isocyanate-reactive diols, such as ethylene glycol and hexylene glycol, having a molecular weight of 62 to 400 daltons, preferably 62 to 450 daltons. The amount of such organic isocyanate-reactive diols is preferably in the range of 0% to 10% by weight, more preferably 0% to 5% by weight, relative to the total amount of the components used to prepare the polyurethane from which the structural units of the polyurethane are derived.

[0069] In a preferred embodiment, the polyol C) is a polyester polyol, a polyether polyol and / or a polycarbonate polyol, optionally in combination with a polyol containing fatty acid residues.

[0070] The amount of component C) is preferably 40 to 89% by weight, more preferably 43 to 83% by weight, even more preferably 47.5 to 77.5% by weight, relative to the total amount of components for preparing the polyurethane from which the structural units of the polyurethane are derived.

[0071] Component D)

[0072] The conversion of the potentially ionic water-dispersing groups present in the prepolymer (obtained by reacting at least A), B') and C) into ionic water-dispersing groups can be carried out by neutralization before, after or simultaneously with the formation of the aqueous dispersion of the prepolymer. Preferably, the conversion of the carboxylic acid groups present in the prepolymer obtained by reacting at least A), B') and C) into salt groups is carried out before or simultaneously with the addition of water to the prepolymer.

[0073] The neutralizing agent D) is a base, which is preferably selected from the group consisting of ammonia, an amine or an inorganic base. Suitable amines include tertiary amines, such as triethylamine or N,N-dimethylethanolamine. Suitable inorganic bases include alkali metal hydroxides and carbonates, such as lithium hydroxide, sodium hydroxide or potassium hydroxide.

[0074] The neutralizing agent is preferably used in such an amount that the molar ratio of ionic and potentially ionic water-dispersing groups to neutralizing groups of the neutralizing agent is in the range of 0.25 to 1.25, more preferably 0.3 to 0.95, even more preferably 0.4 to 0.8.

[0075] In a preferred embodiment of the present invention, the amount of component A) is 10% to 59% by weight, the amount of component B') is 1% to 15% by weight, the amount of component C) is 40% to 89% by weight, and the amount of component E) is 0% to 5% by weight, relative to the total weight of the components for preparing the polyurethane (from which the structural units of the polyurethane are derived). In another preferred embodiment of the present invention, the amount of component A) is 15% to 55% by weight, the amount of component B') is 2% to 9% by weight, the amount of component C) is 42.9% to 82.9% by weight, and the amount of component E) is 0.1% to 4% by weight, relative to the total weight of the components for preparing the polyurethane (from which the structural units of the polyurethane are derived). In another preferred embodiment of the present invention, the amount of component A) is 20% to 50% by weight, the amount of component B') is 2.5% to 6% by weight, the amount of component C) is 47.0% to 77.0% by weight, and the amount of component E) is 0.5% to 3% by weight, relative to the total weight of the components for preparing the polyurethane (the structural units of the polyurethane are derived from the components).

[0076] Component (II)

[0077] Preferably, the isocyanate-terminated polyurethane prepolymer is chain extended with an active hydrogen-containing chain extension compound. Active hydrogen-containing chain extension compounds that can react with isocyanate-terminated prepolymers include water, amino alcohols, primary or secondary diamines or polyamines (including compounds containing primary and secondary amino groups), hydrazines, and substituted hydrazines. Examples of such chain extension compounds that can be used herein include 2-(methylamino)ethylamine, aminoethylethanolamine, aminoethylpiperazine, diethylenetriamine, and alkylenediamines (e.g., ethylenediamine), and cyclic amines (e.g., isophoronediamine). Compounds such as hydrazine, azines such as acetone azine, substituted hydrazines such as dimethylhydrazine, 1,6-hexamethylene-bis-hydrazine, carbodihydrazide, hydrazide of dicarboxylic acids, adipic acid dihydrazide, oxalic acid dihydrazide, isophthalic acid dihydrazide, (di)aminosulfonates, hydrazide prepared by reacting lactone with hydrazine, bis-half-carbodihydrazide, and dihydrazide carbonate of diols may also be useful. Preferably, the chain-extending compound is selected from the group consisting of hydrazine, hydrazide, primary diamine, secondary diamine, compounds containing primary and secondary amino groups, and any mixture thereof.

[0078] Preferably, the molar ratio between the active hydrogen present in the active hydrogen chain-extending compound other than water and the isocyanate (NCO) groups present in the isocyanate-terminated polyurethane prepolymer is in the range of 0.5: 1 to 1.2: 1, more preferably 0.6: 1 to 1.1: 1, especially 0.75: 1 to 1.02: 1, most preferably 0.78: 1 to 0.98: 1. Preferably, the isocyanate-terminated polyurethane prepolymer is blended with an aqueous phase comprising a neutralizing agent and a chain-extending compound, or the neutralized isocyanate-terminated polyurethane prepolymer is added to water comprising a chain-extending compound, or (and more preferably) the neutralized isocyanate-terminated polyurethane is mixed with an aqueous phase and the chain-extending compound is added after blending.

[0079] The polyurethane according to the present invention can be prepared by using a polyol containing fatty acid residues, preferably by using a polyol containing unsaturated fatty acid residues as polyol C). Usually the fatty acid residues are attached by ester bonds or amide bonds. Fatty acids are carboxylic acids with short, medium or long fatty chains that can be linear or branched, saturated or unsaturated. Saturated types can contain 4 to 26 carbons, preferably 8 to 20 carbons. Unsaturated types can contain 14 to 22 carbons, preferably 16 to 20 carbons. Relative to the total weight of the components used to prepare the polyurethane (the structural units of the polyurethane are produced from the components), the amount of fatty acid residues is preferably in the range of 20 wt % to 60 wt %, more preferably 25 wt % to 50 wt %, and most preferably 30 wt % to 45 wt %. For the purpose of determining the fatty acid residue content of the polyurethane, it is convenient to use the weight of the fatty acid reactant containing the ester group formed by the terminal acid group of the fatty acid molecule. "Fatty acid residue" as used herein refers to fatty acids, simple derivatives thereof (such as esters (such as C1-4 The fatty acid residues may be obtained from natural and / or artificial sources. Natural sources include animal and / or plant sources. Animal sources may include animal fat, milk fat, fish oil, lard, liver fat, sperm whale oil and / or beef fat and waxes. Examples of waxes are beeswax, candelia wax and / or montan wax. Plant sources may include waxes and / or oils, such as vegetable oils and / or non-vegetable oils. Examples of vegetable oils include balsam pear oil, borage oil, calendula oil, canola oil, castor oil, chinawood oil, coconut oil, pine nut oil, corn oil, cottonseed oil, dehydrated castor oil, linseed oil, grape seed oil, Jacaranda mimosifolia seed, linseed oil, olive, palm oil, palm kernel oil, peanut oil, pomegranate seed oil, rapeseed oil, safflower oil, loofah oil, soybean oil (soybean oil), sunflower oil, tung oil and / or wheat germ oil. Artificial sources include synthetic waxes (e.g., microcrystalline wax and / or paraffin), distilled tall oil (a byproduct of pinewood processing) and / or synthesis (e.g., by chemical and / or biochemical methods). Suitable fatty acids also include (Z)-hexadec-9-enoic acid [palmitoleic acid] (C 16 H 30 O2), (Z)-octadec-9-enoic acid (C 18 H 34 O2), (9Z,11E,13E)-octadecane-9,11,13-triene [α(alpha)eleostearic acid, also known as α-oleostearic acid] acid (C 18 H 30 O2) (where α-eleostearic acid comprises >65% of tung oil fatty acids), licanic acid, (9Z,12Z)-octadec-9,12-dienoic acid (C 18 H 32 O2), (5Z,8Z,11Z,14Z)-eicosyl-5,8,11,14-tetraenoic acid [arachidonic acid] (C 20 H 32 O2), 12-hydroxy-(9Z)-octadec-9-enoic acid (C 18 H 34 O3), (Z)-docosa-13-enoic acid (C 22 H 42 O2), (Z)-eicos-9-enoic acid (C 20 H 3802), (7Z, 10Z, 13Z, 16Z. 19Z)-docosa-7, 10, 13, 16, 19-eicosapentaenoic acid and / or combinations thereof. Preferred fatty acids are tall oil fatty acids, sunflower fatty acids, soybean fatty acids. Preferably, the fatty acids have a linoleic acid content of at least 20% by weight, more preferably at least 30% by weight, most preferably at least 40% by weight.

[0080] Polyurethanes containing structural units derived from unsaturated fatty acid residues are also known in the art as polyurethane alkyd resins, also known as urethane-modified alkyd resins, see, for example, Autoxidizable urethane resins, DA Wicks and ZW Wicks, Progress in Organic Coatings, November 2005, pages 141-149). Preferred urethane-modified alkyd resins are formed from reactants comprising polyisocyanates (usually diisocyanates) and ester polyols containing unsaturated fatty acid residues. The resulting unsaturation in the polyurethane imparts latent crosslinkability, so that when its coating composition (usually with a metal drier salt) is dried, the film-coated material undergoes crosslinking due to the presence of oxygen in the air, thereby improving the properties of the material, such as its chemical resistance, hardness and durability.

[0081] The present invention relates to an aqueous dispersion comprising dispersed particles comprising a polyurethane as defined in the present invention. The dispersed particles are preferably present in an amount of 20% to 60% by weight, more preferably 35% to 58% by weight, even more preferably 40% to 57% by weight, most preferably 45% to 55% by weight relative to the aqueous dispersion, while the viscosity of the dispersion is advantageously maintained preferably below 1000 mPa.s, more preferably below 800 mPa.s, more preferably below 500 mPa.s, most preferably below 300 mPa.s. The dispersed particles may further comprise at least one other polymer that is not a polyurethane according to the present invention. Preferably, at least one other polymer is an addition polymer obtained by free radical addition polymerization of at least one vinyl monomer. Although such a dispersion may comprise a polyurethane and a vinyl polymer as a simple blend of preformed polymers, it is also known that it is more advantageous to form the vinyl polymer in situ by polymerizing one or more vinyl monomers in the presence of a preformed polyurethane aqueous dispersion. Such in situ formation of the vinyl polymer may be advantageous because it may result in greater stability and may further improve the properties of the resulting coating compared to simple blending. It would therefore be most desirable to apply the foregoing techniques to provide aqueous dispersions of polyurethanes of the type described above which additionally incorporate the in situ formed vinyl polymer.

[0082] Therefore, the present invention further relates to a polyurethane-vinyl polymer hybrid obtained by free radical polymerization of at least one vinyl monomer in the presence of a polyurethane as described above; and to an aqueous dispersion comprising dispersed polyurethane-vinyl polymer hybrid particles.

[0083] Polyurethane-vinyl polymer hybrids refer to vinyl polymers prepared by free radical polymerization of vinyl monomers in the presence of polyurethane; by forming an aqueous dispersion of the polyurethane resin and polymerizing one or more vinyl monomers to form the vinyl polymer, so that the vinyl polymer is in situ incorporated into the aqueous dispersion by polymerizing the vinyl monomers used to form the vinyl polymer in the presence of the polyurethane resin.

[0084] Preferably, the weight ratio of polyurethane to vinyl polymer present in the polyurethane vinyl polymer hybrid is in the range of 95:5 to 15:85, more preferably 90:10 to 35:65, more preferably 90:10 to 50:50, most preferably 90:10 to 65:35.

[0085] The acid value of the polyurethane-vinyl polymer hybrid is preferably in the range of 5 mg KOH / g polymer hybrid to 30 mg KOH / g polymer hybrid, more preferably 5.5 mg KOH / g to 22 mg KOH / g, even more preferably 6 mg KOH / g to 16 mg KOH / g, most preferably 6 mg KOH / g polymer hybrid to 14 mg KOH / g polymer hybrid. The neutralized acid value of the polyurethane-vinyl polymer hybrid is preferably 3 to 35, more preferably 3.5 to 24, more preferably 4 to 16, most preferably 4 to 12, particularly preferably 5 to 10.

[0086] Vinyl polymers are obtained by polymerizing vinyl monomers using conventional free radical generating initiator systems. Suitable free radical generating initiators include mixtures distributed between aqueous and organic phases. Suitable free radical generating initiators include inorganic peroxides (e.g. ammonium persulfate, hydrogen peroxide), organic peroxides (e.g. benzoyl peroxide, alkyl hydroperoxides (e.g. tert-butyl hydroperoxide) and cumene hydroperoxide; dialkyl peroxides, such as di-tert-butyl peroxide; peroxyesters, such as tert-butyl perbenzoate, etc.); mixtures may also be used. Peroxide compounds are advantageously used in some cases in combination with suitable reducing agents (redox systems) such as (isoascorbic acid). Azo compounds such as azobisisobutyronitrile may also be used. Metal compounds such as Fe.EDTA (EDTA is ethylenediaminetetraacetic acid) may also be effectively used as part of a redox initiator system. The amount of initiator or initiator system to be used is conventional, for example in the range of 0.05 wt % to 6 wt % based on the weight of the vinyl monomer used.

[0087] Examples of vinyl monomers include, but are not limited to, 1,3-butadiene, isoprene; trifluoroethyl (meth)acrylate (TFEMA); dimethylaminoethyl (meth)acrylate (DMAEMA); styrene, α-methylstyrene, (meth)acrylamide and (meth)acrylonitrile; vinyl halides, such as vinyl chloride; vinylidene halides, such as vinylidene chloride vinyl ether; vinyl esters, such as vinyl acetate, vinyl propionate, vinyl laurate; vinyl esters of versatic acid, such as VeoVa 9 and VeoVa 10 (VeoVa is a trademark of Resolution Corporation); heterocyclic vinyl compounds; alkyl esters of monoethylenically unsaturated dicarboxylic acids, such as di-n-butyl maleate and di-n-butyl fumarate; dialkyl itaconates, such as dimethyl itaconate, diethyl itaconate, dibutyl itaconate, particularly those of the formula CH2=CR 4 -COOR 5 Acrylates and methacrylates, where R 4 is H or methyl and R 5is an optionally substituted alkyl or cycloalkyl group of 1 to 20 carbon atoms (more preferably 1 to 8 carbon atoms), examples of the acrylic acid ester and the methacrylic acid ester are methyl methacrylate, ethyl methacrylate, n-butyl (meth)acrylate (all isomers), octyl (meth)acrylate (all isomers), 2-ethylhexyl (meth)acrylate, isopropyl (meth)acrylate and n-propyl (meth)acrylate. A preferred formula is CH2=CR 4 -COOR 5 The monomers include isobornyl (meth)acrylate, butyl (meth)acrylate (all isomers), methyl (meth)acrylate, octyl (meth)acrylate (all isomers) and ethyl (meth)acrylate. Preferably, at least 30% by weight, more preferably at least 50% by weight, and even more preferably at least 70% by weight of the total amount of vinyl monomers used to prepare the vinyl polymer is selected from the group consisting of methyl methacrylate, butyl acrylate, butyl methacrylate, acrylonitrile, styrene, and a mixture of two or more of the monomers. Preferably, the vinyl monomers used to prepare the vinyl polymer are selected from the group consisting of styrene, methyl methacrylate, butyl acrylate, butyl methacrylate, and mixtures thereof. More preferably, at least 30% by weight, preferably at least 50% by weight, and more preferably at least 70% by weight of the total amount of vinyl monomers used to prepare the vinyl polymer is selected from styrene or methyl methacrylate.

[0088] The vinyl monomers may include vinyl monomers with functional groups (e.g., crosslinker groups and / or water dispersing groups). Such functional groups may be introduced directly into the vinyl polymer by free radical polymerization, or may be introduced by reacting reactive vinyl monomers followed by reaction with reactive compounds with the desired functional groups. Examples of suitable vinyl monomers providing crosslinking groups include acrylic and methacrylic monomers having at least one free carboxyl or hydroxyl, epoxy, acetoacetoxy or carbonyl group, such as acrylic and methacrylic acid, glycidyl acrylate, glycidyl methacrylate, acetoacetoxyethyl methacrylate, allyl methacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, and diacetone acrylamide.

[0089] Vinyl monomers providing ionic or potentially ionic water-dispersing groups that can be used as additional vinyl monomers include, but are not limited to, (meth)acrylic acid, itaconic acid, maleic acid, citraconic acid, and styrene sulfonic acid. Preferably, the level of vinyl monomers providing ionic or potentially ionic water-dispersing groups is between 0% and 5% by weight of the total level of vinyl monomers used, more preferably between 0% and 1% by weight, and most preferably less than 0.5% by weight.

[0090] Vinyl monomers providing nonionic water dispersible groups may also be used, including alkoxy polyethylene glycol (meth)acrylates, preferably vinyl monomers having a number average molecular weight of 140 to 3000. Examples of such commercially available monomers include methoxy polyethylene glycol (meth)acrylates. Preferably, the weight average molecular weight (Mw) of the resulting vinyl polymer is at least 60,000 Daltons, more preferably in the range of 100,000 Daltons to 6,000,000 Daltons, and most preferably in the range of 150,000 Daltons to 2,500,000 Daltons.

[0091] Coalescing agents (also referred to as film-forming agents or film-forming aids) are used in coating compositions (e.g., paints) to optimize the film-forming process of polymer binder particles. The film-forming process in the coating composition involves the agglomeration of polymer particles during and after the evaporation of the diluent (mainly water in the present invention), thereby allowing adjacent polymer dispersion particles to contact and fuse. Coalescing agents typically reduce the minimum film-forming temperature of the coating composition. Non-limiting examples of coalescing agents are organic cosolvents. Organic cosolvents can be added before, during, or after the polyurethane is formed to control viscosity. Examples of cosolvents that also function as coalescing agents include water-miscible solvents, such as glycols and glycol ethers (e.g., butyl diglycol, dipropylene glycol methyl ether), alcohols such as isopropyl alcohol, acetone, methyl ethyl ketone, and alkyl ethers of ethylene glycol acetate, or mixtures thereof.

[0092] The prepolymer obtained by the reaction of at least A), B'), C) is preferably promoted by adding 1% to 40% by weight of a diluent (relative to the total weight of the components used to prepare the polyurethane prepolymer) to reduce the viscosity of the prepolymer, more preferably 5% to 35% by weight, and even more preferably 10% to 25% by weight of a diluent. Preferably, the diluent is added at the beginning of the reaction of A), B') and C). In the case where the polyurethane is a urethane-modified alkyd resin-vinyl polymer hybrid or a polyurethane-vinyl polymer hybrid, the diluent present during the reaction of A), B') and C) is preferably a vinyl monomer. Otherwise, the diluent is preferably an aprotic organic cosolvent. Examples of cosolvents include water-miscible solvents, such as acetone, methyl ethyl ketone and alkyl ethers of ethylene glycol or propylene glycol and their analogs, or alkyl ethers of ethylene glycol acetate and their analogs, or mixtures thereof. A preferred diluent (d) (other than a vinyl monomer) is acetone or methyl ethyl ketone, because such a diluent can be easily removed from the composition at the end of the polyurethane preparation.

[0093] In the present invention, the NCO:OH molar ratio of the polyurethane prepolymer is preferably higher than 1, more preferably from 1.1 to 3, even more preferably from 1.3 to 2.2.

[0094] The present invention further relates to a coating or paint composition comprising an aqueous dispersion according to the present invention, and preferably further comprising a solvent, a pigment, a dye, a heat stabilizer, a defoamer, a filler, a matting agent, an ultraviolet light (UV) absorber and / or an antioxidant. More specifically, the aqueous dispersion of the present invention can be used in paint applications, even more specifically in decorative paint compositions. It should be understood herein that oil is a wider variety of paints than decorative paints. Decorative paints are typically used to paint smaller surface areas of the surface of a structure (e.g., window decorations, building fascias, doors and door panels, and the surface of door decorations), while general-purpose paints are used to paint most of the wall and facing materials that constitute the surface area of ​​a building.

[0095] The present invention also relates to a method for coating or painting a substrate, the method comprising applying a coating or lacquer composition according to the present invention to a substrate, and causing or allowing volatiles present in the coating or lacquer composition to be removed. The coating or lacquer composition according to the present invention can be applied to a variety of substrates, such as wood, metal, plastic, leather, glass, paper, or a combination of at least two of these materials, optionally containing a primer and a midcoat. The present invention also relates to a coated or painted substrate obtained by this method.

[0096] The present invention will now be further described with reference to the following examples, but the present invention is by no means limited to these examples. Unless otherwise indicated, all parts, percentages and ratios are on a weight basis.

[0097] Examples and comparative experiments

[0098] abbreviation:

[0099] TDI = toluene diisocyanate, a mixture of 2,4-isomer and 2,6-isomer in a weight ratio of 80 / 20.

[0100] HMDI-12 = Dicyclohexylmethane-4,4'-diisocyanate

[0101] IPDI = Isophorone diisocyanate

[0102] MEK = Methyl Ethyl Ketone

[0103] IPA = Isopropyl Alcohol

[0104] Test Method

[0105] Solid content : 2 grams of wet sample were weighed into an aluminum pan on an analytical balance to 0.001 decimal place. The sample was dried in an oven at 130°C under partial vacuum for 1 hour. The percent solids is the final weight divided by the initial weight.

[0106] Particle Size and Polydispersity: Dissolve 1 drop of wet sample in 100 ml of deionized water and place 2 ml of this solution in a polystyrene cuvette, using a concentration roughly between 0.5 g dispersion / liter deionized water and 1.0 g dispersion / liter deionized water. The samples were tested at 22°C + / - 2°C in a Malvern Zetasizer Nano S90, which reports particle size and polydispersity. The machine uses a scattering angle of 90 degrees and is programmed to perform three consecutive measurements. A standard deviation of the average particle size of less than 2.5% is ideal. The average particle size is reported based on the scattering intensity. A polydispersity of less than 0.03 indicates a very monodisperse particle size distribution. From 0.03 to less than 0.08 indicates a unimodal distribution. From 0.08 to 0.20 is not completely unimodal. Above 0.20 is a very wide distribution and can be bimodal or polydisperse.

[0107] Viscosity: The viscosity of a 100 ml sample was measured at 22°C + / - 2°C using a Brookfield viscometer (Model LVDV-IPrime) using a No. 2 spindle at 60 RPM.

[0108] pH: Perform pH measurements by using a calibrated pH meter with a combination electrode. Calibrate the pH meter daily using a two-point or three-point calibration with pH buffers. Rinse and dry the electrode and then place it in the dispersion. When the measurement stabilizes, take the reading.

[0109] precipitation%: The % sedimentation determination of the final dispersion is performed by half filling an ampoule (which is specially designed for this purpose and clearly marked) and diluting it one to one with deionized water. The resulting diluted dispersion is mixed thoroughly by shaking or inverting the sealed ampoule and then placed in a Centrifuge at 1500 rpm for 15 min in a Rotanta 460, Model 5600-01. Sedimentation was measured by reading the line on the ampoule where the sedimentation level could be visually checked and multiplying the reading by 2 to accommodate the dilution.

[0110] Acid value: The acid value is determined by calculation according to the following formula: [the equivalent number of acid groups present in 1 gram of solid polymer]*56100

[0111] Acid value can also be determined according to ASTM D1639-90 (1996) e1. According to the procedure, a sample dissolved in a good solvent is titrated with an alcoholic potassium hydroxide solution of known concentration (KOH). The difference in titration volume between the sample and the blank is a measure of the acid value of the solid according to the following formula:

[0112] AV=[(V 空白 -V 样品 )*N KOH *56.1] / (W*S / 100)

[0113] in

[0114] AV is the solid acid value in mg KOH / g solid material, V 空白 is the volume of KOH solution used in the blank, V 样品 is the volume of KOH solution used in the sample, N KOH is the normality of the KOH solution, W is the sample weight in grams, S is the solid content of the sample in %. The measurements were performed in duplicate on a Metrohm 702SM Titrino titrator using a potentiometric endpoint (the measurement result was accepted if the difference between the duplicates was <0.1 mg KOH / g solid matter).

[0115] Neutralized acid value: The neutralized acid value is calculated by multiplying the acid value calculated above by the degree of neutralization (expressed in stoichiometric amounts).

[0116] Example 1: Preparation of OH-terminated fatty acid ester modified polyurethane

[0117] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 247 g of a diol made from the diepoxide of bisphenol A and linoleic acid (equivalent weight = 450, OH number = 120) (0.55 equiv) and 13.3 g of diisopropanolamine (0.2 equiv). The reactor was heated to 60° C. and 11.4 g of glutaric anhydride (0.1 equiv) was added over 5 minutes. The reaction of the amine with the anhydride was monitored by infrared until the anhydride band completely disappeared. 42 g of a second polyol (0.14 equiv) made by the reaction of glycerol with linoleic acid (equivalent weight = 300, OH number = 185) was added together with 21 g (0.04) of a nonionic diol made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1. The mixture was stirred and heated to 60°C, and 52.4 g (0.4 equivalent) of HMDI-12 and 44.4 g (0.4 equivalent) of IPDI were added. After a few minutes, 9.1 g of 2-hydroxyethyl methacrylate was added, and the reactor was heated to 90°C until no isocyanate was detected by infrared. The system was cooled to 80°C, and 53 g of MEK and 57 g of isopropyl alcohol IPA were added.

[0118] A dispersion of the resin was prepared by neutralizing the carboxylic acid groups of the diol amic acid obtained by reacting diisopropanolamine with glutaric anhydride by adding 7.12 g (0.08 equivalent) of dimethylaminoethanol. Then, under vigorous stirring, 630 g of water was added within 10 minutes. The dispersion was placed under vacuum to remove the MEK and IPA solvents and a product with a pH of 8.4 in water, a solid content of 38.5%, a particle size of 77 nm, a polydispersity of 0.177 and a viscosity of 100 mPa.s (100 centipoise (cps)) was obtained. When stored at room temperature for at least two months, the sample was visually stable, with no precipitate formed, no phase separation observed, and no significant increase in viscosity (producing a gel-like substance) observed. When stored in an oven at 50°C for 30 days, the sample also remained visually stable, with no precipitate formed, no phase separation observed, and no significant increase in viscosity (producing a gel-like substance) observed.

[0119] Example 2: Preparation of OH-terminated fatty acid ester modified polyurethane-vinyl polymer hybrids

[0120] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 247 g of a diol made from the diepoxide of bisphenol A and linoleic acid (equivalent weight = 450, OH number = 120) (0.55 equiv) and 13.3 g of diisopropanolamine (0.2 equiv). The reactor was heated to 60° C. and 11.4 g of glutaric anhydride (0.1 equiv) was added over 5 minutes. The reaction of the amine with the anhydride was monitored by infrared until the anhydride band completely disappeared. 42.0 g of a second polyol (0.14 equiv) made by the reaction of glycerol with linoleic acid (equivalent weight = 300, OH number = 185) was added together with 21 g (0.04) of a nonionic diol made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1. The mixture was stirred and heated to 60°C, and 52.4 g (0.4 equivalent) of HMDI-12 and 44.4 g (0.4 equivalent) of IPDI were added. After a few minutes, 9.1 g of 2-hydroxyethyl methacrylate was added, and the reactor was heated to 90°C until no isocyanate was detected by infrared. The system was cooled to 80°C, and 53 g of MEK and 57 g of isopropanol were added.

[0121] A dispersion of the resin was prepared by neutralizing the carboxylic acid groups of the diol amic acid obtained by reacting diisopropanolamine with glutaric anhydride by adding 3.56 g (0.04 equivalent) of dimethylaminoethanol. Then, under vigorous stirring, 630 g of water was added over 10 minutes. To this dispersion was added 110 g of methyl methacrylate followed by the addition of 2.2 g of Bruggolite FF6M (from Bruggeman Chemical) in 55 g of water plus 3.14 g of a redox couple of 70% tert-butyl hydroperoxide in 31 g of water over a period of 1 hour. The dispersion was placed under vacuum to remove the MEK and IPA solvents and a product having a pH of 7.52 in water, a solids content of 46.5%, a particle size of 116 nm, a polydispersity of 0.07 and a viscosity of 462 mPa.s (462 cps) was obtained. The samples were visually stable at room temperature and no precipitate was formed, no phase separation, and no large increase in viscosity (producing a gel-like substance) was observed for at least 2 months.

[0122] Example 3: Preparation of OH-terminated fatty acid ester modified polyurethane

[0123] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 247 g of a diol made from the diepoxide of bisphenol A and linoleic acid (equivalent weight = 450, OH number = 120) (0.55 equiv) and 13.3 g of diisopropanolamine (0.2 equiv). The reactor was heated to 60° C. and 11.4 g of glutaric anhydride (0.1 equiv) was added over 5 minutes. The reaction of the amine with the anhydride was monitored by infrared until the anhydride band completely disappeared. 22.5 g of a second polyol (0.08 equiv) made by the reaction of glycerol with linoleic acid (equivalent weight = 300, OH number = 185) was added together with 21 g (0.04 equiv) of a nonionic diol made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1. The mixture was stirred and heated to 60°C, and 52.4 g (0.4 equivalent) of HMDI-12 and 44.4 g (0.4 equivalent) of IPDI were added. After a few minutes, 9.1 g of 2-hydroxyethyl methacrylate was added, and the reactor was heated to 90°C until no isocyanate was detected by infrared. The system was cooled to 80°C, and 53 g of MEK and 57 g of isopropyl alcohol IPA were added.

[0124] A dispersion of the resin was prepared by neutralizing the carboxylic acid groups of the diol amic acid obtained by reacting diisopropanolamine with glutaric anhydride by adding 7.12 g (0.08 equivalent) of dimethylaminoethanol. Then, under vigorous stirring, 550 g of water was added within 10 minutes. The dispersion was placed under vacuum to remove the MEK and IPA solvents, and a product with a pH of 7.24 in water, a solid content of 44.7%, a particle size of 121 nm, a polydispersity of 0.078 and a viscosity of 51 mPa.s (51 cps) was obtained. The sample was visually stable at room temperature after observation for at least 2 months, and no precipitate was formed, no phase separation was observed, and no significant increase in viscosity (producing a gel-like substance) was observed.

[0125] Example 4: Preparation of OH-terminated fatty acid ester modified polyurethane

[0126] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 247 g of a diol made from the diepoxide of bisphenol A and linoleic acid (equivalent weight = 450, OH number = 120) (0.55 equiv) and 13.3 g of diisopropanolamine (0.2 equiv). The reactor was heated to 60° C. and 11.4 g of glutaric anhydride (0.1 equiv) was added over 5 minutes. The reaction of the amine with the anhydride was monitored by infrared until the anhydride band completely disappeared. 22.5 g of a second polyol (0.08 equiv) made by the reaction of glycerol with linoleic acid (equivalent weight = 300, OH number = 185) was added together with 21 g (0.04 equiv) of a nonionic diol made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1. The mixture was stirred and heated to 60°C, and 52.4 g (0.4 equivalent) of HMDI-12 and 44.4 g (0.4 equivalent) of IPDI were added. After a few minutes, 9.1 g of 2-hydroxyethyl methacrylate was added, and the reactor was heated to 90°C until no isocyanate was detected by infrared. The system was cooled to 80°C, and 53 g of MEK and 57 g of isopropanol were added.

[0127] A dispersion of the resin was prepared by neutralizing the carboxylic acid groups of the diol amic acid obtained by reacting diisopropanolamine with glutaric anhydride by adding 7.12 g (0.08 equivalent) of dimethylaminoethanol. Then, under vigorous stirring, 550 g of water was added within 10 minutes. The dispersion was placed under vacuum to remove the MEK and IPA solvents and a product having a pH of 8.4 in water, a solid content of 50%, a particle size of 124 nm, a polydispersity of 0.067 and a viscosity of 850 mPa.s (850 cps) was obtained. The sample was visually stable at room temperature after observation for at least 2 months, with no precipitate formed, no phase separation observed, and no significant increase in viscosity (producing a gel-like substance) observed.

[0128] Example 5: Preparation of NCO-terminated polyurethane

[0129] Into a reactor kettle equipped with an overhead stirrer, a thermometer, and a nitrogen source, 93.5 g of Diexter-G6555-120 polyol (a saturated linear polyester, which is a poly(hexamethylene / neopentyl adipate) diol with a 1,6-hexanediol / neopentyl glycol molar ratio of 55 / 45, from Coim USA inc.) and 4.66 g of diisopropanolamine were placed. The two components were mixed and heated to 50° C. Once the temperature was reached, 3.99 g of glutaric anhydride was added in portions while mixing. The components were heated to 60° C. and mixed for 30 minutes. After 30 minutes, 9.47 g of a nonionic diol (0.04 equivalents) made from TDI, diethanolamine, and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1 was added and mixed. After this, 75.24 g of HMDI-12 isocyanate was added and mixed thoroughly for 10 minutes. 25.0 g of MEK was then added to the reactor. The reactor was then heated to 78 ° C and maintained at this temperature until the actual NCO% of the prepolymer was 6.05%. The prepolymer was then cooled to 55 ° C and 25.0 g of acetone was added, followed by neutralization with 2.12 g of triethylamine. The urethane dispersion was then prepared by pouring the 50 ° C neutralized prepolymer into a solution of 277 g of water, 0.37 g of sodium bicarbonate, 1.2 g of Surfynol 465 (a nonionic dynamic wetting agent for reducing surface tension, from Air Products) at 20 ° C over a period of 20 minutes. Once all the neutralized prepolymers were added to the water, it was mixed for another 5 minutes, and then 24.44 g of 16% hydrazine solution was added to extend the urethane polymer chain. MEK and acetone were stripped off by a rotary evaporator. The polyurethane dispersion had a pH of 7.51, a viscosity of 48 mPa.s (48 cps), a solids content of 47.0%, a particle size of 184 nm, and a polydispersity of 0.27. When stored at room temperature for at least 10 days, the sample appeared to be visually stable, with neither precipitation nor phase separation nor a large increase in viscosity (resulting in a gel-like substance) observed. When stored in an oven at 50° C. for 30 days, the sample also remained visually stable, with neither precipitation nor phase separation nor a large increase in viscosity (resulting in a gel-like substance) observed.

[0130] Example 6: Preparation of NCO-terminated polyurethane

[0131] Into a reactor kettle equipped with an overhead stirrer, a thermometer and a nitrogen source, 93.5 g of Diexter-G6555-120 polyol and 12.64 g of diisopropanolamine were placed. The two components were mixed and heated to 50° C. Once the temperature was reached, 9.69 g of glutaric anhydride was added in portions while mixing. The components were heated to 60° C. and mixed for 30 minutes. After 30 minutes, 11.14 g of a nonionic diol (0.04 equivalents) made of TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1 was added and mixed. After this, 105.6 g of HMDI-12 isocyanate was added and mixed thoroughly for 10 minutes. Then 30.0 g of MEK was added to the reactor. The reactor was then heated to 78° C. and maintained at this temperature until the prepolymer reached an actual NCO value of 6.42%. The prepolymer was then cooled to 55°C and 30.0 g of acetone was added before neutralization with 5.16 g of triethylamine. The urethane dispersion was then prepared by pouring the neutralized prepolymer at 50°C into a solution of 377 g of water, 0.37 g of sodium bicarbonate, 1.2 g of Surfynol 465 at 20°C over a period of 20 minutes. Once all the neutralized prepolymer was added to the water, it was allowed to mix for an additional 5 minutes before 32.15 g of 16% hydrazine solution was added to chain extend the urethane polymer. The MEK and acetone were stripped off by rotary evaporator. The polyurethane dispersion had a pH of 7.2, a viscosity of 200 mPa.s (200 cps), a solids content of 44.4%, a particle size of 60 nm, and a polydispersity of 0.08. The dispersion was diluted with water to 32% solids and then observed to remain stable at room temperature for at least 2 weeks, with neither precipitation nor phase separation nor a large increase in viscosity (resulting in a gel-like substance) observed.

[0132] Example 7: Preparation of OH-terminated fatty acid ester modified polyurethane-vinyl polymer hybrids

[0133] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 250 g of a diol made from the diepoxide of bisphenol A and linoleic acid (equivalent weight = 450, OH number = 120) (0.56 equiv) and 13.3 g of diisopropanolamine (0.2 equiv). The reactor was heated to 60° C. and 15.2 g of tetrahydrophthalic anhydride (0.1 equiv) was added over 5 minutes. The reaction of the amine with the anhydride was monitored by infrared until the anhydride band completely disappeared. 42.0 g of a second polyol (0.14 equiv) made by the reaction of glycerol with linoleic acid (equivalent weight = 300, OH number = 185) was added together with 17.3 g (0.033) of a nonionic diol made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1. The mixture was stirred and heated to 60°C, and 43.2 g (0.32 equivalent) of HMDI-12 and 52.2 g (0.47 equivalent) of IPDI were added. After a few minutes, 9.1 g of 2-hydroxyethyl methacrylate was added, and the reactor was heated to 90°C until no isocyanate was detected by infrared. The system was cooled to 80°C, and 85 g of methyl methacrylate MMA and 90 g of isopropanol were added.

[0134] A dispersion of the resin was prepared by neutralizing the carboxylic acid groups of the diol amic acid obtained by reacting diisopropanolamine with tetrahydrophthalic anhydride by adding 5.34 g (0.06 equivalent) of dimethylaminoethanol. Then, under vigorous stirring, 600 g of water were added over 10 minutes. Over a period of 1 hour, a redox couple of 1.89 g of Bruggolite FF6M in 45 g of water plus 2.7 g of tert-butyl hydroperoxide 70% in 25 g of water was added to the dispersion. The dispersion was placed under vacuum to remove the IPA solvent and a product with a pH of 7.5 in water, a solids content of 52%, a particle size of 197 nm, a polydispersity of 0.06 and a viscosity of 69 mPa.s (69 cps) was obtained. The sample remained visually stable at room temperature for at least 2 months of observation, with neither the formation of precipitates nor the observation of phase separation nor a substantial increase in viscosity (producing a gel-like substance) being observed.

[0135] Example 8: Preparation of NCO-terminated polyurethane

[0136] 93.5 g of Diexter-G6555-120 polyol (0.2 eq.) and 3.06 g of diisopropanolamine (0.05 eq.) were placed in a reactor equipped with an overhead stirrer, a thermometer, and a nitrogen source. The two components were mixed and heated to 60° C. 2.62 g of glutaric anhydride (0.023 eq.) was added and mixed for 30 minutes. The reaction of the amine and the anhydride was monitored by infrared until the anhydride band disappeared completely. 9.47 g of a nonionic diol made of TDI, diethanolamine, and methoxypolyethylene glycol 750 (equivalent weight 557, 0.017 eq.) from Dow Chemical Company in a molar ratio of 1:1:1 was added and mixed for 10 min. 75.24 g of HMDI-12 (0.570 eq.) was added and mixed for 10 min. 25 g of MEK was added and heated and mixed at 78°C for 2.5 hours until the isocyanate% was 5.98%. Cooled to 55°C and diluted with 25 g of acetone and 1.40 g of triethylamine (0.0138 eq.) was added. Dispersed in water prepared with sodium bicarbonate (0.37 g) and surfactant Surfynol 465 (1.2 g) over 5 min, maintaining the temperature between 28-32°C. The polymer was extended with 23.84 g of hydrazine (16% solution, 0.238 eq.). MEK and acetone were stripped off by rotary evaporator. The final dispersion had a solids content of 46.25%, a particle size of 209 nm and a polydispersity of 0.3. The sample was visually stable at room temperature for at least 3 months of observation, with no precipitate formed, no phase separation observed, and no significant increase in viscosity (producing a gel-like substance) observed.

[0137] Comparative experiment A: Preparation of fatty acid ester modified polyurethane

[0138] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 354 g of a diol made from the diepoxide of bisphenol A and linoleic acid (equivalent weight = 450, OH number = 120) (0.75 equivalent) and 10.7 g of dimethylol propionic acid (0.16 equivalent). 26 g of a nonionic diol (0.05) made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1 was added. The mixture was stirred and heated to 60°C, and 83.3 g (0.75 equivalent) of IPDI was added. The reactor was heated to 90°C until no isocyanate was detected by infrared. The system was cooled to 60°C, and 198 g of acetone was added.

[0139] The acid groups of 2,2-dimethylolpropionic acid were neutralized by adding 8.9 g (0.09 equivalent) of triethylamine. Then, 645 g of water were added over 10 minutes with vigorous stirring, resulting in a viscous gel-like paste rather than a fluid dispersion.

[0140] Comparative Experiment B: Preparation of fatty acid ester-modified polyurethane similar to Example 1.

[0141] A 1000 ml round bottom flask equipped with a stirrer and a nitrogen blanket was charged with 247 g of a diol (equivalent weight = 450, OH number = 120) (0.52 equivalents) made from the diepoxide of bisphenol A and linoleic acid and 13.4 g (0.2 equivalents) of 2,2-dimethylolpropionic acid. 42 g of a second polyol (0.14 equivalents) (equivalent weight = 300, OH number = 185) made by reacting glycerol with linoleic acid was added together with 21 g (0.04) of a nonionic diol made from TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a molar ratio of 1:1:1. The mixture was stirred and heated to 60°C, and 52.4 g (0.4 equivalents) of HMDI-12 and 44.4 g (0.4 equivalents) of IPDI were added. After a few minutes, 9.1 g of 2-hydroxyethyl methacrylate was added and the reactor was heated to 90° C. until no isocyanate was detected by infrared. The system was cooled to 80° C. and 53 g of MEK and 57 g of isopropanol were added.

[0142] A dispersion of the resin was prepared by adding 7.12 g (0.08 equivalent) of dimethylaminoethanol to neutralize the carboxylic acid groups of 2,2-dimethylolpropionic acid. Then, under vigorous stirring, 630 g of water was added over 10 minutes. As the water was added, the system became very thick and formed a gel paste and was not fluid.

[0143] Comparative experiment C: Preparation of a polyurethane similar to Example 5.

[0144] Into a reactor kettle equipped with an overhead stirrer, thermometer and nitrogen source, 93.5 g of Diexter-G6555-120 polyol and 4.69 g of 2,2-dimethylol propionic acid were placed. The components were heated to 60°C and mixed for 30 minutes, followed by the addition of 9.47 g of a nonionic diol made by reacting TDI, diethanolamine and methoxypolyethylene glycol 750 (equivalent weight = 510) from Dow Chemical Company in a 1:1:1 molar ratio. After this, 75.24 g of HMDI-12 isocyanate was added and mixed thoroughly for 10 minutes. 25.0 g of MEK was then added to the reactor. The reactor was then heated to 78°C and maintained at this temperature until the prepolymer was just below the theoretical NCO value of 2.34%. The prepolymer was then cooled to 55°C and 25.0 g of acetone was added, followed by neutralization with 2.12 g of triethylamine. The neutralized urethane prepolymer at 50°C was poured into a solution of 277g water, 0.37g sodium bicarbonate, 1.2g Surfynol 465 at 20°C over a period of 20 minutes. The prepolymer would not disperse and formed a solid mass at the bottom of the dispersion vessel.

[0145] In Table 1 below, the present invention using amic acid diols is compared to ester acid diols and the conventional method of stabilizing urethane dispersions with DMPA.

[0146] Table 1

[0147]

Claims

1. An aqueous dispersion comprising dispersed particles, wherein the dispersed particles comprise polyurethane, wherein the polyurethane comprises structural units derived from at least a) at least one organic polyisocyanate, b) at least one isocyanate-reactive compound with carboxylate groups for providing pendant carboxylate ion dispersing groups in the polyurethane, and c) at least one organic isocyanate-reactive polyol, At least one of the compounds b) having a carboxylate group has the following structural formula in R1 is a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms, or a divalent cycloaliphatic hydrocarbon group having 6 to 8 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 8 carbon atoms, R2 and R3 are 2-hydroxypropyl.

2. The aqueous dispersion according to claim 1, wherein R1 is a divalent aliphatic hydrocarbon group having 3 to 6 carbon atoms, or a divalent cycloaliphatic hydrocarbon group having 6 to 8 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 8 carbon atoms.

3. The aqueous dispersion according to any one of claims 1 to 2, wherein the polyurethane is the reaction product of at least A) at least one organic polyisocyanate, B') at least one carboxylic acid-bearing compound for providing pendant carboxylate ion dispersing groups in the polyurethane, C) at least one organic isocyanate-reactive polyol, and D) at least one neutralizing agent for neutralizing at least a portion of the carboxylic acid groups, At least one of the carboxylic acid-bearing compounds B') has the following structural formula wherein R1, R2 and R3 are as defined in claim 1 or 2.

4. The aqueous dispersion according to claim 3, wherein the carboxylic acid-bearing compound B') of formula (2) is a reaction product of diisopropanolamine and a cyclic anhydride selected from the group consisting of glutaric anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and any mixture thereof.

5. The aqueous dispersion according to claim 3, wherein the carboxylic acid-bearing compound B') of formula (2) is a reaction product of glutaric anhydride and diisopropanolamine.

6. The aqueous dispersion according to claim 3, wherein at least 50% by weight of the component B') is according to formula (2).

7. The aqueous dispersion of claim 3, wherein the polyurethane is the reaction product of at least (I) an at least partially neutralized isocyanate-terminated polyurethane prepolymer formed by reacting at least (A), (B'), (C) and (D) at a degree of neutralization of 125% to 25%, and (II) Chain extension compounds containing active hydrogen. 8 . The aqueous dispersion according to claim 1 , wherein the polyurethane has an acid value of 5 to 30 mg KOH / g polyurethane.

9. The aqueous dispersion according to claim 1, wherein the polyurethane is a urethane-modified alkyd polymer comprising an ester polyol containing unsaturated fatty acid residues as polyol C), and wherein the amount of fatty acid residues is in the range of 20% to 60% by weight relative to the total weight of the components for preparing the polyurethane from which the structural units of the polyurethane are derived.

10. The aqueous dispersion according to claim 1, wherein the organic polyisocyanate A) is a polyisocyanate containing at least two free isocyanate groups.

11. The aqueous dispersion according to claim 10, wherein the organic polyisocyanate A) is a diisocyanate Y(NCO)2, wherein Y represents a divalent aliphatic hydrocarbon group having 4 to 10 carbon atoms, a divalent cycloaliphatic hydrocarbon group having 6 to 13 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 13 carbon atoms, or a divalent aromatic aliphatic hydrocarbon group having 7 to 15 carbon atoms. 12 . The aqueous dispersion according to claim 1 , wherein the polyol C) is a polyester polyol, a polyether polyol and / or a polycarbonate polyol, optionally in combination with a polyol containing fatty acid residues.

13. The aqueous dispersion of claim 1, wherein the dispersed particles further comprise at least one vinyl polymer, and the vinyl polymer is obtained in situ by free radical addition polymerization of one or more vinyl monomers in the presence of a preformed aqueous dispersion of the polyurethane of claim 1, and wherein the acid value of the polyurethane-vinyl polymer hybrid is in the range of 5 mg KOH / g polymer hybrid to 30 mg KOH / g polymer hybrid.

14. The aqueous dispersion according to claim 1, wherein the dispersed particles have a particle size of 15 nm to 1000 nm as measured according to a method performed in a Malvern Zetasizer Nano S90, and the acid value of the dispersed polyurethane is 5 mg KOH / g to 30 mg KOH / g.

15. The aqueous dispersion according to claim 1, wherein the dispersed particles are present in the aqueous dispersion in an amount of 20 to 60 wt% relative to the aqueous dispersion, wherein the viscosity of the dispersion is lower than 1000 mPa.s as measured by a method performed in a Malvern Zetasizer NanoS90.

16. A coating or paint composition comprising the aqueous dispersion according to any one of claims 1 to 15.

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