Waterborne polyurethane dispersion and composition containing the same

Abstract

The present invention relates to an aqueous polyurethane dispersion and a composition containing the same. The polyurethane is obtained by reacting the following components: at least two polyols, a polyisocyanate, a chain extender, and a neutralizer; wherein the at least two polyols include a polyol having a tertiary amine group.

Description

Technical Field

[0001] The present invention relates to an aqueous polyurethane dispersion (PUD), and more particularly, to a cationic aqueous polyurethane dispersion (CAPUD). The PUD is particularly useful for improving the mechanical properties of polyurethane foams, genuine leather, synthetic leather, or fabrics. Background Art

[0002] Polyurethane (PU) is widely used in leather finishing, wood coatings, paints, adhesives, plastics, steel, textiles, footwear, and paper due to its wide range of adjustable hardness, low-temperature resistance, excellent flexibility, and strong adhesion. Solvent-based PUs typically use large amounts of organic solvents, and the resulting volatile organic compounds (VOCs) can have adverse effects on the environment and the human body. With increasingly stringent environmental regulations worldwide, the demand for and performance requirements for waterborne PUs have been increasing in recent years.

[0003] During the preparation of waterborne polyurethanes, to obtain a stably dispersed polyurethane emulsion, hydrophilic groups are generally introduced into the polyurethane oligomer (prepolymer) molecules, enabling emulsification in water. Depending on the charge of the introduced groups, waterborne polyurethanes can be categorized as cationic waterborne polyurethanes (CAPUD), anionic waterborne polyurethanes, nonionic waterborne polyurethanes, and hybrid waterborne polyurethanes.

[0004] Common waterborne polyurethane dispersions are mostly anionic. Cationic waterborne polyurethane (CAPUD) is a type of polyurethane that is susceptible to yellowing, particularly at high temperatures, due to its inherent urethane structure and the presence of quaternary ammonium ions. This makes CAPUD susceptible to yellowing, which is exacerbated by high temperatures. Therefore, commercialization of CAPUD remains challenging.

[0005] When a waterborne polyurethane dispersion is used as a basecoat in a coating, a protective clearcoat is generally applied over the basecoat. However, clearcoats typically contain organic solvents. If the basecoat film based on the waterborne polyurethane dispersion has poor solvent resistance, the organic solvents in the clearcoat will corrode the surface of the coating, resulting in problems such as loss of gloss or uneven color.

[0006] If waterborne polyurethane dispersion is used as a surface treatment agent or as the outermost topcoat in a coating, the end product will encounter situations where it will be cleaned or wiped with solvents (such as alcohol), and the solvent resistance requirements are more stringent.

[0007] Therefore, there is an urgent need in the art for a novel CAPUD that has a simple preparation method and improves the aforementioned disadvantages (e.g., improved yellowing resistance at high temperatures (hereinafter referred to as "heat yellowing resistance") and / or solvent resistance). Summary of the Invention

[0008] In view of the above problems, the present invention first provides an aqueous polyurethane dispersion, wherein the polyurethane is obtained by reacting the following components: at least two polyols, a polyisocyanate, a chain extender, and a neutralizer; wherein the at least two polyols include a polyol having a tertiary amine group.

[0009] The present invention further provides a coating composition comprising the aqueous polyurethane dispersion of the present invention and a colorant.

[0010] The present invention further provides an adhesive composition comprising the aqueous polyurethane dispersion of the present invention and a resin. DETAILED DESCRIPTION

[0011] To facilitate understanding of the disclosure set forth herein, several terms are defined below.

[0012] All numbers expressing amounts, ratios, physical characteristics, and the like used in this specification and claims are to be understood as being modified in all instances by the term "about." As used herein, the term "about" means an acceptable error for the particular value as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined.

[0013] Herein, unless otherwise specified, the singular forms "a," "an," and "the" also include the plural forms. Any and all examples and exemplary terms ("for example," "for example," and "such as") herein are intended only to further illustrate the present disclosure and are not intended to limit the scope of the present invention. The terms in this specification should not be construed as implying that any unclaimed method or condition may constitute an essential feature for practicing the present invention.

[0014] The word "or" with respect to a list of two or more items includes all of the following interpretations: any one of the items in the list, all of the items in the list, and any combination of the items in the list.

[0015] All ranges disclosed herein should be understood to encompass any and all subranges subsumed therein. For example, the range of "1 to 10" should be considered to include any and all subranges between a minimum of 1 and a maximum of 10, including both the maximums 1 and 10; that is, all subranges starting with a minimum of 1 or greater and ending with a maximum of 10 or less, such as 1 to 6.7, 3.2 to 8.1, or 5.5 to 10, and any number within that range, such as 2.6, 4.7, or 7.3.

[0016] As used herein, "polyurethane" refers to a polymer including oligomers (e.g., prepolymers) containing a carbamate group "-OC(=O)-NH-". As is known in the art, polyurethanes may contain other groups in addition to carbamate groups, such as, but not limited to, urea, alloate, biuret, carbodiimide, oxazolidinyl, isocyanurate, uretdione, ester, ether, carbonate, hydrocarbon, fluorocarbon, alcohol, thiol, amine, hydrazide, siloxane, silane, ketone, or olefin, etc.

[0017] As used herein, an "aqueous dispersion" refers to a dispersion that contains a substantial amount of water. In some aspects, the aqueous dispersion contains at least 5% by weight of water, based on the total weight of all solvents (including water), such as, but not limited to, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 90% by weight. Suitable water content ranges may include any combination of these values. The aqueous dispersion may contain other ingredients, such as water-compatible organic solvents. For example, an aqueous polyurethane dispersion of the present invention may mean a dispersion comprising water and a polyurethane, wherein the polyurethane is dispersed in an aqueous medium containing at least 20% by weight of water. The dispersion may also contain water-compatible organic materials (such as alcohols and other polar organic solvents).

[0018] The aqueous polyurethane dispersion of the present invention is obtained by reacting the polyurethane with the following ingredients: at least two polyols, a polyisocyanate, a chain extender, and a neutralizer. The aqueous polyurethane dispersion achieves stable dispersion in water by introducing ionic hydrophilic groups into the polyurethane molecules. Ionic hydrophilic groups can be classified as anionic (e.g., dimethylolpropionic acid and sulfonates) or cationic (e.g., N-methyldiethanolamine), depending on the type of neutralization. In some aspects, the aqueous polyurethane dispersion is a cationic aqueous polyurethane dispersion (CAPUD).

[0019] The polyurethane contained in the CAPUD of the present invention can be prepared by forming a polyurethane oligomer, chain extension, and neutralization (quaternization). The following details the composition and preparation of the polyurethane of the present invention, in conjunction with the above steps.

[0020] Formation of polyurethane oligomers:

[0021] The polyurethane oligomers disclosed herein are formed from a polyisocyanate and at least two polyols. The at least two polyols include a polyol having a tertiary amine group. The polyol having a tertiary amine group is hydrophilic (and can be used as a hydrophilic chain extender), which improves the dispersibility of the polyurethane in water, making it transparent and stably dispersed in water. The polyol can provide a source of active hydrogen for reaction with isocyanate groups via the -NCO+HX→-NH-C(=O)-X reaction. In some aspects, in addition to the polyol having a tertiary amine group described herein, the at least two polyols further include another polyol different from the polyol having a tertiary amine group (hereinafter referred to as "other polyol").

[0022] In some aspects, the polyisocyanate may first react with other polyols to form an intermediate, which is then reacted with a polyol having a tertiary amine group to form a polyurethane oligomer. The reaction equation is shown below:

[0023] - Formation of intermediates:

[0024]

[0025] - Formation of polyurethane oligomers:

[0026]

[0027] wherein R1, R2, R3, R4 and R5 each independently represent a saturated straight-chain or branched saturated hydrocarbon group, which may have 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and most preferably 1 to 4 carbon atoms, such as but not limited to: methyl, ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, isobutyl, tert-butyl), pentyl, hexyl and the like.

[0028] I.1 Polyisocyanates

[0029] In some aspects, the polyisocyanate has an average of greater than one isocyanate group; the polyisocyanate has an average of more than two isocyanate groups; the polyisocyanate has an average of more than three isocyanate groups; the polyisocyanate has an average of more than four isocyanate groups.

[0030] In some aspects, the polyisocyanate includes aliphatic polyisocyanates, aromatic polyisocyanates, heterocyclic polyisocyanates, and oligomerization products thereof. The polyisocyanates may be used alone or as a mixture of two or more. Dimers, trimers, and oligomers of the above polyisocyanates may also be used.

[0031] Suitable aliphatic polyisocyanates may be chain aliphatic polyisocyanates or cyclic aliphatic polyisocyanates (hereinafter referred to as "cycloaliphatic polyisocyanates").

[0032] Suitable chain aliphatic polyisocyanates include, but are not limited to, α,Ω-alkylene diisocyanates having 5 to 20 carbon atoms, such as hexamethylene-1,6-diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, 2,4,4-trimethyl-hexamethylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, lysine diisocyanate, etc. Preferred chain aliphatic polyisocyanates include, but are not limited to, hexamethylene-1,6-diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, or 2,4,4-trimethyl-hexamethylene diisocyanate.

[0033] Suitable cycloaliphatic polyisocyanates include, but are not limited to, dicyclohexylmethane diisocyanate (DIISOCYANATE) and dicyclohexylmethane diisocyanate (DIISOCYANATE). 12 MDI), isophorone diisocyanate (IPDI), cyclohexane diisocyanate, bis-(isocyanomethyl)cyclohexane, methylcyclohexane diisocyanate, cyclohexane triisocyanate, isomers thereof, etc. Preferred cycloaliphatic polyisocyanates include, but are not limited to, dicyclohexylmethane diisocyanate or isophorone diisocyanate.

[0034] Suitable aromatic polyisocyanates include, but are not limited to, 4,4'-methylenediphenyl diisocyanate (MDI), toluene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, tetralinapthylene diisocyanate, diphenylene diisocyanate, dimethyldiphenylene diisocyanate, dichlorodiphenylene diisocyanate, triphenylmethane triisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, 1,4-xylylene diisocyanate, 1,3-xylylene diisocyanate, and isomers thereof. Preferred aromatic polyisocyanates include, but are not limited to, 4,4'-methylenediphenyl diisocyanate or toluene diisocyanate.

[0035] Suitable heterocyclic isocyanates include, but are not limited to, 5,5′-methylenebisfuran isocyanate, 5,5′-isopropylidenebisfuran isocyanate, isomers thereof, and the like.

[0036] I.2 At least two polyols

[0037] Herein, the at least two polyols include a polyol having a tertiary amine group and “other polyols”.

[0038] Herein, "polyol" is a material having two or more hydroxyl groups or functional groups that can be reduced to hydroxyl groups and react with NCO-groups in the molecule.

[0039] The polyols used in the present invention are long-chain polyols (e.g., those with a number-average molecular weight (Mn) of 80 g / mol to 10,000 g / mol) with an average of two or more hydroxyl groups or functional groups reducible to hydroxyl groups and reactive with NCO- groups per molecule. These polyols possess active hydrogens reactive with polyisocyanates, reacting with isocyanate groups via the following reaction: -NCO + HX → -NH-C(=O)-X. Higher molecular weight polyols contribute to the formation of soft segments in polyurethanes, while lower molecular weight polyols contribute to the formation of hard segments.

[0040] In some aspects, based on the total weight of the reactants for forming the polyurethane, the lower limit of the amount of the at least two polyols is 25 weight%, and the upper limit of the amount of the at least two polyols is 55 weight%. Suitable amounts of the at least two polyols are, for example but not limited to, 25 weight%, 26 weight%, 27 weight%, 28 weight%, 29 weight%, 30 weight%, 31 weight%, 32 weight%, 33 weight%, 34 weight%, 35 weight%, 36 weight%, 37 weight%, 38 weight%, 39 weight%, 40 weight%, 41 weight%, 42 weight%, 43 weight%, 44 weight%, 45 weight%, 46 weight%, 47 weight%, 48 weight%, 49 weight%, 50 weight%, 51 weight%, 52 weight%, 53 weight%, 54 weight% or 55 weight%, and ranges thereof can be any combination of the above values.

[0041] I.2.1 Polyols with tertiary amine groups

[0042] In the present invention, a polyol with a tertiary amine group reacts its active hydrogen atoms via the reaction -NCO+HX→-NH-C(=O)-X. After the reaction, the polyol is located on the backbone of the polyurethane oligomer, providing nitrogen atoms that can be quaternized. Therefore, the polyol with a tertiary amine group not only acts as a chain extender but also enhances the hydrophilicity of the polyurethane oligomer, significantly improving the appearance and dispersion stability of CAPUD. The inventors have discovered that poor water dispersibility of polyurethane can easily lead to a milky white appearance and even delamination of the CAPUD. In contrast, the present invention effectively improves the dispersibility of the polyurethane in water by introducing hydrophilic groups from a polyol with a tertiary amine group into the polyurethane backbone. The resulting CAPUD exhibits a transparent appearance and is stable and free of delamination.

[0043] In some aspects, the number average molecular weight (Mn) of the polyol having a tertiary amine group is limited to 80 g / mol, and the upper limit of the Mn of the polyol having a tertiary amine group is 500 g / mol. Suitable Mn values ​​include, but are not limited to, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 250, 260, 280, 300, 350, 400, 450, or 500 g / mol, and the range can be any combination of the above values. In some aspects, the polyol having a tertiary amine group includes, but is not limited to, N-methyldiethanolamine (N-MDEA), N-ethyldiethanolamine (EDEA), N-propyldiethanolamine (PDEA), N-butyldiethanolamine (BDEA), or 3-(dimethylamino)-1,2-propanediol. The polyol having a tertiary amino group may be used alone or as a mixture of two or more.

[0044] In some aspects, the amount of the polyol having a tertiary amine group is 6 to 15 weight %, based on the total weight of all polyols and polyisocyanates. Suitable amounts of the polyol having a tertiary amine group are, for example, but not limited to, 6 weight %, 6.5 weight %, 7 weight %, 7.5 weight %, 8 weight %, 8.5 weight %, 9 weight %, 9.5 weight %, 10 weight %, 10.5 weight %, 11 weight %, 11.5 weight %, 12 weight %, 12.5 weight %, 13 weight %, 13.5 weight %, 14 weight %, 14.5 weight % or 15 weight %.

[0045] I.2.2 “Other polyols”

[0046] In some aspects, the other polyol comprises: a polyether polyol, a polyester polyol, or a polycarbonate polyol.

[0047] In some aspects, the lower limit of the number average molecular weight (Mn) of the other polyols is 500 g / mol, and the upper limit of the number average molecular weight (Mn) of the polyols is 10,000 g / mol. Suitable number average molecular weights (Mn) are, for example, but not limited to, 500, 1,000, 1,500, 2,000, 2,500, 3,000, 3,500, 4,000, 4,500, 5,000, 5,500, 6,000, 6,500, 7,000, 7,500, 8,000, 8,500, 9,000, 9,500, or 10,000, and ranges thereof can be any combination of the above values.

[0048] Polyether polyols can be obtained in a known manner by reacting a starting compound containing reactive hydrogen atoms (e.g., water or a diol used to prepare polyester polyols) with an alkylene oxide, such as, but not limited to, ethylene oxide, propylene oxide, butylene oxide, ethylene oxide, tetrahydrofuran, epichlorohydrin, or a mixture thereof. Preferred polyethers include polytetrahydrofuran (PTHF) and poly(propylene glycol) (PPG).

[0049] Polyester polyols are typically esterified products prepared by reacting an organic carboxylic acid with a stoichiometric amount of a diol. Suitable polyols for use in the reaction include, but are not limited to, polyethylene glycol adipate, polyethylene terephthalate polyol, polycaprolactone polyol, phthalate polyol, sulfonated polyol, or mixtures thereof.

[0050] In some aspects, organic carboxylic acids used to make polyester polyols include dicarboxylic acids and tricarboxylic acids and anhydrides, such as maleic acid, maleic anhydride, succinic acid, glutaric acid, glutaric anhydride, adipic acid, suberic acid, pimelic acid, azelaic acid, sebacic acid, chlorobridgeic acid, 1,2,4-butanetricarboxylic acid, phthalic acid, isomers of phthalic acid, phthalic anhydride, fumaric acid, tetrabromophthalic anhydride and acids, dimerized fatty acids such as oleic acid, and mixtures thereof. Preferred polycarboxylic acids used to make polyester polyols include aliphatic or aromatic dibasic acids.

[0051] The diols used to make polyester polyols can be aliphatic diols, cycloaliphatic diols or aromatic diols, such as but not limited to: alkylene glycols, such as ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, hexanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol; other diols, such as bisphenol-A, cyclohexanediol ... Dimethanol (1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl-2-ethylpropane-1,3-diol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, caprolactone diol, dimer ester diol, hydroxylated bisphenol, polyether diol, halogenated diol, or mixtures thereof. Preferred diols include ethylene glycol, butanediol, hexanediol, and neopentyl glycol.

[0052] In some aspects, the polyester polyol is a polyester diol, such as, but not limited to, hexanediol neopentyl glycol, adipic acid polyester diol, propylene glycol maleic anhydride adipic acid polyester diol, hexanediol neopentyl glycol, and fumaric acid polyester diol.

[0053] In some aspects, the polycarbonate polyol may be a compound obtained by reacting a diol with a diaryl carbonate (such as, but not limited to, diphenyl carbonate). In some aspects, the diol used to produce the polycarbonate polyol may be, for example, but not limited to, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, or a mixture thereof.

[0054] The inventors of the present application have also discovered that, in the present invention, using polycarbonate polyol can make CAPUD have better solvent resistance than using polyester polyol and / or polyether polyol as other polyols, which is beneficial for the application of the obtained CAPUD in anti-fingerprint paint resin.

[0055] In some aspects, other polyols further include, for example but not limited to, polycaprolactone polyols, polyamide polyols, polyesteramide polyols, polyacetal polyols, polythioether polyols, polysiloxane polyols, ethoxylated polysiloxane polyols, halogenated polyester polyols, halogenated polyether polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, polyisoprene polyols, polyisobutylene polyols, alkyd-modified polyols, polythioether polyols, hydroxyl-containing acrylic and methacrylic polymers and copolymers, or hydroxyl-containing epoxides.

[0056] The above-mentioned other polyols may be used alone or as a mixture of two or more.

[0057] In some aspects, based on the total weight of all polyols and polyisocyanates, the lower limit of the amount of other polyols is 28 weight percent, and the upper limit of the amount of other polyols is 50 weight percent. Suitable amounts of other polyols include, but are not limited to, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 weight percent, and the range can be any combination of the above values.

[0058] As shown in the reaction equation above, the resulting polyurethane oligomer is terminated with isocyanate groups (NCO). In some aspects, the molar ratio of isocyanate groups (NCO) of the polyisocyanate used in the present invention to hydroxyl groups (OH) of all polyols is 1.5 to 2. Suitable ratios include, but are not limited to, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, or 2, and any combination of these values ​​may be included.

[0059] If necessary, hindered phenols can be added during the formation of polyurethane oligomers. Hindered phenols can capture peroxide free radicals and / or alkoxy free radicals to inhibit the oxidation reaction of polyurethane, thereby improving the heat yellowing resistance. Preferred hindered phenols include, but are not limited to, 2,6-tert-butyl-4-methylphenol, bis(3,5-tert-butyl-4-hydroxyphenyl) sulfide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Ciba 1010), or a combination thereof.

[0060] The amount of hindered phenol can be adjusted as needed. In some aspects, based on the total weight of all polyols and polyisocyanates, the lower limit of the amount of hindered phenol is 0.5 wt.%, and the upper limit of the amount of hindered phenol is 1 wt.%. Preferred amounts of hindered phenol include, but are not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 wt.%, and any combination thereof can be included.

[0061] II. Chain extension of polyurethane oligomers:

[0062] II.1 Chain Extenders

[0063] The present invention further utilizes a chain extender to increase the molecular weight of the polyurethane oligomer. The chain extender used in the present invention may comprise a di- or polyfunctional alcohol or a di- or polyfunctional amine, preferably a short-chain di- or polyfunctional alcohol or di- or polyfunctional amine (i.e., a short-chain polyol or short-chain polyamine). When the chain extender comprises a polyamine, the polyamine can form a urea bond (-NHCONH-) with an isocyanate group, which has a stronger polarity than a urethane bond (-NHCOO-). Therefore, the polyurethane obtained using a chain extender comprising a polyamine exhibits improved mechanical strength, mechanical modulus, and heat resistance.

[0064] In some aspects, the polyamine comprises an inorganic amine having an average of more than 2 primary amine groups, secondary amine groups, or a combination thereof. In some aspects, the polyamine comprises an organic polyamine having an average of more than 2 primary amine groups, secondary amine groups, or a combination thereof.

[0065] In some preferred aspects, the polyamine chain extender is an organic polyamine chain extender such as, but not limited to, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), m-xylylenediamine (MXDA), 2-methylpentanediamine, propylenediamine, butanediamine, diethylenetriamine, hexamethylenediamine, cyclohexanediamine, phenylenediamine, toluenediamine, 3,3-dichlorobenzidine, 4,4'-methylene-bis-(2-chloroaniline), 3,3-dichloro-4,4-diaminodiphenylmethane, or mixtures thereof. In some preferred aspects, the polyamine chain extender is an inorganic polyamine chain extender such as, but not limited to, hydrazine (H2N-NH2), substituted hydrazines, and hydrazine hydrate (H2N-NH2·H2O), or mixtures thereof.

[0066] In some aspects, to chain extend the polyurethane oligomer of the present invention, a solvent (for example, but not limited to, a ketone solvent, such as acetone or butanone) may be added to dilute and disperse the polyurethane oligomer after the polyurethane oligomer is formed, and then a chain extender may be added to the diluted polyurethane oligomer dispersion.

[0067] In some aspects, the specific reaction equation of the polyurethane oligomer and the polyamine chain extender is as follows:

[0068]

[0069] wherein R1, R2, R3, R4, and R5 independently have the meanings described above; R6 represents a linear, branched, or aromatic hydrocarbon group having 1 to 20 carbon atoms; and m = 0 or 1. In the above reaction equation, m = 0 indicates the use of hydrazine as the chain extender.

[0070] In some aspects, the number average molecular weight (Mn) of the chain extender has a lower limit of 18 g / mol and an upper limit of 500 g / mol. Suitable number average molecular weights (Mn) are, for example but not limited to, 18, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500, and the range can be any combination of the above values.

[0071] In some aspects, the lower limit of the ratio of the amine groups of the polyamine chain extender to the NCO groups of the polyisocyanate, based on moles, is 0.5; the upper limit of the ratio of the amine groups of the polyamine chain extender to the NCO groups of the polyisocyanate is 1. Suitable ratios include, but are not limited to, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or 1, and the range can be any combination of the above values.

[0072] The aforementioned chain extenders can be used alone or as a mixture of two or more.

[0073] III. Quaternization treatment to form cationic polyurethane:

[0074] III.1 Neutralizer

[0075] To increase the hydrophilicity of the polyurethane and form a stably dispersed CAPUD, a neutralizing agent may be added to the polyurethane of the present invention. This neutralizing agent treats the corresponding nitrogen atoms in the polyurethane backbone, imparting cationic charges to the nitrogen atoms through acid neutralization / quaternization to form ammonium cation centers. In some aspects, the reaction equation for acid-neutralized / quaternized polyurethane is shown below:

[0076]

[0077] wherein R1, R2, R3, R4, R5, R6 and m each independently have the meanings as described above.

[0078] Taking hydrazine as a chain extender as an example, the reaction of acid neutralization / quaternization of polyurethane is the state where m=0 in the above equation.

[0079] Theoretically, tertiary amine groups on the polyurethane backbone can be quaternized with any known neutralizing agent. However, in the present invention, the inventors unexpectedly discovered that using a specific polyacid combination as a neutralizing agent not only increases the number of ionic and / or hydrogen bonds within the polyurethane molecules, leading to an increase in the intermolecular crosslink density and thus improving the solvent resistance of the CAPUD, but also significantly improves the thermal yellowing resistance of the resulting CAPUD.

[0080] In some preferred aspects, the neutralizing agent of the present invention comprises at least two acids, which has advantages such as good stability. In addition, the applicant has found that when the neutralizing agent comprises an organic acid and an inorganic acid, it has the advantage of excellent yellowing resistance. In some aspects, the molar ratio of the organic acid to the inorganic acid is 35 to 50. Suitable molar ratios of the organic acid to the inorganic acid are, for example, but not limited to, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, 40, 40.5, 41, 41.5, 42, 42.5, 43, 43.5, 44, 44.5, 45, 45.5, 46, 46.5, 47, 47.5, 48, 48.5, 49, 49.5 or 50, and the range can be any combination of the above values.

[0081] The organic acid that can be used in the present invention includes formic acid. The inorganic acid that can be used in the present invention includes a polybasic inorganic acid. In some aspects, the polybasic inorganic acid that can be used in the present invention includes phosphoric acid or sulfuric acid.

[0082] In a preferred aspect, the neutralizing agent used in the present invention comprises formic acid and a polybasic inorganic acid selected from the group consisting of phosphoric acid and sulfuric acid. In some preferred aspects, the neutralizing agent comprises formic acid and phosphoric acid, or formic acid and sulfuric acid, or formic acid, phosphoric acid and sulfuric acid.

[0083] In some aspects, the molar ratio of the neutralizing agent to the tertiary amine-containing polyol is 1.1 to 1.7. Suitable molar ratios of the neutralizing agent to the tertiary amine-containing polyol include, but are not limited to, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, or 1.7, and any combination thereof may be included. It has been found that neutralizing agents comprising formic acid and an inorganic acid selected from the group consisting of phosphoric acid and sulfuric acid are particularly preferred. Formic acid contains an aldehyde group, which has antioxidant properties, and thus can improve the heat-yellowing resistance of polyurethanes. Phosphoric acid increases intramolecular ionic and / or hydrogen bonding, enhancing solvent resistance. This allows the production of CAPUDs with excellent stability, no delamination, and good heat-yellowing resistance. Furthermore, the applicant has discovered that when the molar ratio of formic acid to phosphoric acid is 35 to 50, and the molar ratio of the neutralizer to the tertiary amine-containing polyol is 1.1 to 1.7, a synergistic effect is produced between formic acid and phosphoric acid, resulting in even better thermal yellowing resistance and solvent resistance of the resulting CAPUD.

[0084] In some aspects, the neutralized / quaternized polyurethane is dispersed in water to form CAPUD.

[0085] In some aspects, the tertiary amine groups on the polyurethane backbone are partially neutralized with an acid before dispersing the polyurethane in water. In some aspects, the tertiary amine groups on the polyurethane backbone are partially neutralized with an acid during dispersing the polyurethane in water. In some aspects, the lower limit of the neutralization degree of the tertiary amine groups on the polyurethane backbone is 10 mol%, and the upper limit of the neutralization degree of the tertiary amine groups on the polyurethane backbone is 100 mol%. Suitable tertiary amine neutralization degrees include, but are not limited to, 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol%, 98.5 mol%, 99 mol%, 99.5 mol%, or 100 mol%, and the range can be any combination of the above values. Herein, the neutralization degree of the tertiary amine groups on the polyurethane backbone refers to the proportion of one or more nitrogen atoms on the polyurethane backbone that are neutralized / quaternized. In some embodiments, an excess of acid can be used over the equivalent amount of nitrogen atoms in the polyurethane backbone.

[0086] In some aspects, the solvent used to disperse the polyurethane oligomer described above can be removed as needed.

[0087] In some aspects, the CAPUD of the present invention can be manufactured using known polyurethane technology with various other ingredients and features. Such additives include surfactants, stabilizers, defoamers, antimicrobial agents, antioxidants, rheology modifiers, or mixtures thereof. These additives can be optionally applied before and / or during processing of the CAPUD into a final product, as is known in the art.

[0088] The upper limit of the solid content of the CAPUD of the present invention is 40%, and the lower limit of the solid content is 20%. Suitable solid contents include, but are not limited to, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, or 40%, and the range can be any combination of the above values.

[0089] The upper limit of the pH of the CAPUD of the present invention is 6. Suitable pH values ​​include, but are not limited to, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6, and any combination of these values ​​may be included. It has been found that a pH greater than 6 results in insufficient quaternization and / or insufficient hydrophilicity of the polyurethane, making it difficult to disperse in water and detrimental to storage stability.

[0090] The viscosity of the CAPUD of the present invention can be selected based on actual application requirements. A suitable upper limit of the viscosity is 500 cps, and a lower limit of the viscosity is 10 cps. Suitable viscosities include, but are not limited to, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500 cps, and any combination of the above values ​​may be included.

[0091] Contrary to the inventors' expectations, the polyurethane backbone of the present invention contains optimized ammonium cationic groups, making the CAPUD of the present invention particularly suitable for polyurethane foam, genuine leather, synthetic leather, or fabrics, thereby improving their mechanical properties. In some aspects, the polyurethane backbone of the present invention has a positive charge, compared to anionic waterborne polyurethane dispersions, resulting in improved wettability on the substrates to which it is applied. In some aspects, the CAPUD of the present invention exhibits low sensitivity to water hardness, allowing for use in acidic environments.

[0092] In some embodiments, the CAPUD of the present invention contains substantially no free amines. In some embodiments, the CAPUD of the present invention has a substantially low volatile organic compound (VOC) content (<0.5%).

[0093] In some embodiments, the CAPUD of the present invention imparts improved bonding strength to leather, and can provide the leather with a soft, natural, and plump appearance / feel.

[0094] In some embodiments, the CAPUD of the present invention imparts improved tear strength, abrasion resistance, wrinkle resistance and / or resilience to fabrics. In some embodiments, the CAPUD of the present invention imparts improved antistatic properties to chemical fiber fabrics.

[0095] In some embodiments, the CAPUD of the present invention imparts improved adhesion, mechanical strength, and / or water resistance to metal surfaces or metal fasteners.

[0096] In some embodiments, the CAPUD of the present invention is suitable for surface treatment of printed paper and fabric. In some embodiments, the CAPUD of the present invention is suitable for anti-elasticity or permanent wash-free treatment of fabric.

[0097] In some embodiments, the CAPUD of the present invention can be used together with any known colorant to form a coating composition.

[0098] In some embodiments, the CAPUD of the present invention can be used together with any known resin to form an adhesive composition.

[0099] Example

[0100] The present invention is further described in detail below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art may make some non-essential improvements and adjustments to the present invention based on the above-mentioned content of the present invention, which still fall within the scope of protection of the present invention. Before discussing several non-limiting embodiments of the present invention, it should be understood that the present invention is not limited to the details of the specific non-limiting embodiments shown and discussed herein in its application, because the present invention may have other embodiments. In addition, the terms used to discuss the present invention in this article are for descriptive rather than limiting purposes. Furthermore, unless otherwise indicated, the following discussion of similar numbers refers to similar elements.

[0101] Example 1: Preparation of CAPUD samples

[0102] The reagents and raw materials used in the following CAPUD samples are described in Table 1:

[0103] Table 1

[0104]

[0105] The amounts of the following reagents used in each CAPUD sample are listed in Table 2:

[0106] Table 2

[0107]

[0108] Formation of polyurethane oligomer: Add 180g of ETEROL 5650-1000 and 67.5g of ETEROL 5650-3000 to a four-necked flask equipped with an electric stirrer, a temperature controller, and a reflux condenser, and then remove water in vacuo at 120°C for 1 hour. After cooling to 65°C, add 96.5g of IPDI and H 12 MDI 228g and Ciba 3.54 g of 1010 was added to a four-necked flask and reacted at 80° C. for 1 hour. Then 70.65 g of N-MDEA was added to the four-necked flask, and the temperature was raised to 90° C. and maintained at this temperature for 3 hours to produce an NCO-terminated polyurethane oligomer.

[0109] Polyurethane Oligomer Chain Extension: After the mixture is cooled to 70°C, 372g of acetone is added to a four-necked flask to dilute the polyurethane oligomer, and the temperature is then lowered to 45°C. 26.7g of 80% hydrazine hydrate and 27g of deionized water are thoroughly mixed and added dropwise to the four-necked flask over 10 minutes, followed by continuous stirring for 15 minutes.

[0110] Quaternization treatment to form cationic polyurethane: At 25°C, thoroughly mix the amounts of formic acid, acetic acid, and / or phosphoric acid corresponding to each CAPUD sample shown in Table 2 with 1143g of deionized water in a rotating water tank. Then, over 10 minutes, add the acetone-diluted polyurethane oligomer in the four-necked flask to the rotating water tank containing formic acid, acetic acid, and / or phosphoric acid, and rapidly stir and mix for 30 minutes. Finally, add the defoamer. 0.5 g of Foamex 800 was added and vacuum was performed to remove acetone to prepare each CAPUD sample.

[0111] Example 2: Preparation of heat-resistant yellowing and solvent-resistant test samples

[0112] The CAPUD samples 1 to 9 obtained in Example 1 were coated on the surface of a galvanized steel sheet to form a coating, which was then dried at 150° C. for 1 minute to obtain a CAPUD galvanized steel sheet corresponding sample with a dry film thickness of 1 μm.

[0113] Example 3: Physical properties of various CAPUD samples

[0114] Table 3 shows the physical properties of each CAPUD sample:

[0115] Table 3

[0116]

[0117] In Table 3, the measurement methods of various properties are as follows.

[0118] Solids content measurement: First, weigh and record the weight of an empty aluminum dish. Next, weigh 1-2g of the CAPUD sample and place it in the dish. Allow it to level. Then, place it on a hot plate and bake it at 150°C for 15 minutes. Finally, weigh the combined weight (baked sample + aluminum dish) and calculate the solids content.

[0119] Solid content% = (baked sample + aluminum dish - empty aluminum dish) / weight of undried sample

[0120] pH measurement: The CAPUD sample was kept at a constant temperature of 25°C for 1 hour and then measured using a pH meter.

[0121] Viscosity measurement: The CAPUD sample was kept at a constant temperature of 25°C for 1 hour and then measured using a Brookfield LVF#2 at 60 rpm.

[0122] Thermal yellowing resistance was measured using the color difference between the corresponding CAPUD galvanized steel samples before and after high-temperature baking. Before placing the corresponding CAPUD galvanized steel samples from Example 2 in the oven, the b*1 value of each CAPUD galvanized steel sample was measured using a colorimeter. The samples were then baked in a 150°C oven for 30 minutes and then removed. The b*2 value of each CAPUD galvanized steel sample after baking was again measured using a colorimeter. Finally, the Δb value (i.e., b*2 - b*1) was calculated to assess thermal yellowing resistance.

[0123]

[0124] Solvent resistance was measured by rubbing ethanol onto cotton wool. Using an abrasion tester (Model A20-339) with a 1.0 kg load, the corresponding CAPUD galvanized steel specimens from Example 2 were rubbed back and forth 5, 10, 15, and 20 times. The specimens were visually inspected for gloss loss.

[0125]

[0126] As shown in Table 3, CAPUD samples 1-5 and 7 all achieved Δb values ​​less than 3 in the heat yellowing resistance test. CAPUD samples 1-6 and 9 also demonstrated solvent resistance, with the ability to withstand over 10 rubs without losing gloss. Among these samples, CAPUD samples 1-3 exhibited significantly better heat yellowing resistance (Δb values ​​less than 2) and solvent resistance (able to withstand over 20 rubs).

[0127] The organic acid / inorganic acid molar ratio of CAPUD Sample 4 was 83.34. Without being bound by theory, it has been found that when the organic acid / inorganic acid molar ratio is greater than 50, the strength of the ionic and / or hydrogen bonds between polyurethane molecules is weakened, resulting in inferior solvent resistance compared to CAPUD Samples 1-3. The organic acid / inorganic acid molar ratio of Sample 5 was 18.62. Without being bound by theory, it has been found that when the organic acid / inorganic acid molar ratio (particularly the formic acid / inorganic acid molar ratio; see the description of Sample 6 below) is less than 35, the antioxidant capacity of CAPUD is weakened, resulting in inferior heat yellowing resistance compared to CAPUD Samples 1-3.

[0128] Compared to Sample 1, Sample 6 used acetic acid instead of formic acid, maintaining the organic acid / inorganic acid molar ratio at 37.86. However, Sample 6 exhibited poorer thermal yellowing resistance than Sample 1. Without being bound by theory, this is believed to be due to the lack of antioxidant properties of acetic acid.

[0129] Sample 7 has poor solvent resistance compared to Samples 1 to 3. Without being bound by theory, it is believed that this is because Sample 7 only uses formic acid as a neutralizing agent, and formic acid cannot provide ionic bonds and / or hydrogen bonds between polyurethane molecules.

[0130] Compared to Samples 1-3, Sample 8 exhibited poor thermal yellowing resistance and solvent resistance. Without wishing to be bound by theory, this is believed to be because Sample 8 used only acetic acid as a neutralizing agent, which cannot provide ionic and / or hydrogen bonds between polyurethane molecules and lacks antioxidant properties.

[0131] Sample 9 has poor yellowing resistance compared to Samples 1 to 3. Without being bound by theory, it is believed that this is because Sample 9 only uses phosphoric acid as a neutralizing agent, and phosphoric acid does not have antioxidant properties.

[0132] Those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the scope or spirit of the present invention. In view of the foregoing, the present invention is intended to cover modifications and variations of the present invention, provided that they fall within the scope of the claims and their equivalents.

Claims

1. An aqueous polyurethane dispersion, wherein the polyurethane is obtained by reacting the following components: at least two polyols, polyisocyanates, Chain extenders, and neutralizing agent; The at least two polyols include a polyol having a tertiary amine group, the neutralizer includes an organic acid and an inorganic acid, and the organic acid includes formic acid.

2. The aqueous polyurethane dispersion according to claim 1, wherein the inorganic acid is selected from the group consisting of phosphoric acid and sulfuric acid.

3. The aqueous polyurethane dispersion according to claim 1, wherein the ratio of the organic acid to the inorganic acid is 35 to 50 on a molar basis.

4. The aqueous polyurethane dispersion according to any one of claims 1 to 3, wherein the amount ratio of isocyanate groups (NCO) of the polyisocyanate to hydroxyl groups (OH) of all polyols is 1.5 to 2 on a molar basis.

5. The aqueous polyurethane dispersion according to any one of claims 1 to 3, wherein the chain extender comprises a polyamine, wherein the ratio of the amine groups of the polyamine to the NCO groups of the polyisocyanate is 0.5 to 1 on a molar basis.

6. The aqueous polyurethane dispersion according to any one of claims 1 to 3, wherein the polyol having a tertiary amino group is selected from the group consisting of N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-butyldiethanolamine and 3-(dimethylamino)-1,2-propylene glycol.

7. The aqueous polyurethane dispersion according to any one of claims 1 to 3, wherein the chain extender is a polyamine selected from the group consisting of hydrazine, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), m-xylylenediamine (MXDA), 2-methylpentanediamine, propylenediamine, butanediamine, diethylenetriamine, hexamethylenediamine, cyclohexanediamine, phenylenediamine, toluenediamine, 3,3-dichlorobenzidine, 4,4'-methylene-bis-(2-chloroaniline), 3,3-dichloro-4,4-diaminodiphenylmethane, and the like.

8. The aqueous polyurethane dispersion according to any one of claims 1 to 3, wherein the amount of the polyol having a tertiary amine group is 6 to 15 wt%, based on the total weight of all polyols and the polyisocyanate. 9 . The aqueous polyurethane dispersion according to claim 1 , wherein the neutralizing agent is used in an amount ratio of 1.1 to 1.7 based on moles to the polyol having a tertiary amine group. 10 . A coating composition comprising the aqueous polyurethane dispersion according to claim 1 and a colorant. 11 . An adhesive composition comprising the aqueous polyurethane dispersion according to claim 1 and a resin.

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