CN113698567B

CN113698567B - Hydrophilic siloxane modified polyurethane or polyurethane-urea aqueous dispersion, preparation method and application

Info

Publication number: CN113698567B
Application number: CN202010435533.8A
Authority: CN
Inventors: 尹逊迪; 纪学顺; 晋云全; 刘姗; 王萃萃
Original assignee: Wanhua Chemical Group Co Ltd; Wanhua Chemical Ningbo Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd; Wanhua Chemical Ningbo Co Ltd
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2023-01-13
Anticipated expiration: 2040-05-21
Also published as: CN113698567A

Abstract

The invention provides a hydrophilic siloxane modified polyurethane or polyurethane-urea aqueous dispersion and a preparation method thereof, which can be applied to the fields of coatings, adhesives and the like. Siloxane groups can be introduced on the surfaces of polyurethane or polyurethane-urea aqueous dispersion colloidal particles through siloxane with hydrophilic groups, and the siloxane groups on the surfaces of the colloidal particles are hydrolyzed and crosslinked during the drying and activating processes of the aqueous dispersion, so that the crosslinking density is increased, and the heat resistance, the damp heat resistance and the like of the adhesive obtained by the aqueous dispersion are obviously improved.

Description

Hydrophilic siloxane modified polyurethane or polyurethane-urea aqueous dispersion, preparation method and application

Technical Field

The invention belongs to the technical field of polyurethane dispersions, and particularly relates to a hydrophilic siloxane modified polyurethane or polyurethane-urea aqueous dispersion, a preparation method and application thereof.

Background

The polyurethane or polyurethane-urea aqueous dispersion only takes water as a dispersion medium, has no pollution to the environment in the using process, is non-combustible, non-explosive, safe and reliable, and is widely applied to the fields of coatings, adhesives and the like. However, most of the waterborne polyurethane has a linear structure, and the water resistance, the solvent resistance, the heat resistance and the like of the waterborne polyurethane are not ideal, so that the application range of the waterborne polyurethane is limited. In order to improve the resistance of aqueous polyurethanes, crosslinking or crosslinkable groups are usually introduced into the aqueous polyurethane.

In order to improve the adhesion properties of the aqueous polyurethane-polyurea dispersions, the crosslinking density can be increased by reacting the residual hydroxyl groups in the aqueous polyurethane-polyurea dispersion with isocyanates by means of the addition of isocyanate curing agents during use. In the patent US4870129A, hydroxyl is introduced into polyurethane or polyurethane-polyurea by adopting the method, and is compounded with isocyanate when in use, so that the adhesive strength and the heat resistance are obviously improved. However, in this method, the isocyanate reacts with water in addition to the hydroxyl group, resulting in a shortened working time of the adhesive, and the adhesive can be prepared just as it is, which brings extra trouble to the construction.

CN102216359A introduces a polyurethane or polyurethane-polyurea dispersoid with terminal carboxyl, and the polyurethane or polyurethane-polyurea dispersoid can quickly generate a crosslinking reaction after being compounded with carbodiimide due to the high activity of the terminal carboxyl, so that the film coating performance is obviously improved. However, carboxylic acids catalyze the hydrolysis of ester bonds, which affects the stability of aqueous polyurethane or polyurethane urea dispersions, and carbodiimides are inherently poorly stable, which is detrimental to the storage of such systems.

In addition, siloxane can be introduced into polyurethane or polyurethane-urea for self-crosslinking, so that the crosslinking density of the system is increased, and the product performance is improved. Patent CN 108250390A discloses a polyurethane or polyurethane-urea aqueous dispersion with a side chain containing a non-steric hindrance siloxane group, in the drying and activating processes, siloxanes on the side chain are hydrolyzed and crosslinked with each other, so that the crosslinking density is increased, but the siloxanes with low polarity can migrate into colloidal particles in the preparation process of the aqueous dispersion, so that the collision probability among the siloxanes is reduced, most of the siloxanes are crosslinked in the colloidal particles, and the activation performance of a product is seriously influenced while excellent heat resistance is obtained.

Disclosure of Invention

The invention aims to provide a hydrophilic siloxane modified polyurethane or polyurethane-urea aqueous dispersion applicable to the fields of coatings, adhesives and the like and a preparation method thereof, aiming at the problem of poor resistance of the conventional aqueous polyurethane or polyurethane-urea. Siloxane groups can be introduced on the surfaces of polyurethane or polyurethane-urea aqueous dispersion colloidal particles through siloxane with hydrophilic groups, and the siloxane groups on the surfaces of the colloidal particles are hydrolyzed and crosslinked during the drying and activating processes of the aqueous dispersion, so that the crosslinking density is increased, and the heat resistance, the damp heat resistance and the like of the adhesive obtained by the aqueous dispersion are obviously improved.

In order to achieve one aspect of the above purpose, the invention adopts the following technical scheme:

an aqueous polyurethane or polyurethane-urea dispersion, the reaction product resulting from the reaction of a composition comprising:

a) At least one siloxane i) component,

the siloxane i) has the general formula:

wherein the group R contains at least one isocyanate reactive group and at least one hydrophilic group, and at least one group in R1, R2 and R3 is methoxy or ethoxy;

b) At least one polyol component having a functionality of 2 to 4;

c) At least one polyisocyanate component;

d) At least one component of a hydrophilic compound having hydrophilic groups comprising one or both of ionic groups and potentially ionic groups, said hydrophilic compound containing from 2 to 3 isocyanate-reactive groups; the ionic groups are preferably carboxylate and/or sulfonate groups; the potential ionic group is preferably a carboxyl group and/or a sulfonic group; the isocyanate reactive groups are preferably hydroxyl and/or amino groups;

e) Optionally, a component of an isocyanate-reactive nonionic hydrophilic compound;

f) Optionally, a compound containing 1 to 3 NCO-reactive functional groups, preferably a compound containing 1 to 3 amino and/or hydroxyl groups in the molecule;

g) Optionally, other isocyanate reactive compounds.

The component a) is used in an amount of 0.05 to 4wt%, preferably 0.2 to 2.5wt%, based on the total solid weight of the composition; the amount of component b) is from 60 to 92% by weight, preferably from 75 to 90% by weight; the amount of component c) is from 6 to 30% by weight, preferably from 8 to 20% by weight; the amount of component d) is from 0.2 to 5.5% by weight, preferably from 1 to 3% by weight; the amount of component e) is from 0 to 6% by weight, preferably from 0.5 to 3% by weight; the amount of component f) is from 0 to 7% by weight, preferably from 0.5 to 3% by weight; the amount of component g) is 0 to 2 wt.%.

The hydrophilic groups of the siloxane i) are selected from one or more of ionic groups, potentially ionic groups and non-ionic groups; the ionic groups are preferably carboxylate and/or sulfonate groups; the potentially ionic group is preferably a carboxyl group and/or a sulfonic group; the nonionic group is preferably a polyoxyethylene ether.

The isocyanate-reactive groups of the siloxane i) comprise one or both of hydroxyl and secondary amino groups.

Said siloxane i) being obtainable by reacting a siloxane ii) with a compound having hydrophilic and/or potentially hydrophilic groups; including, but not limited to, a reaction between isocyanate and an isocyanate-reactive group, a reaction between an epoxy group and an amino group, a ring-opening reaction between an amino group and a sultone or lactone, an addition reaction between an amino group and a double bond, or an addition reaction between a hydrosilane and an allyl group;

the siloxane ii) is selected from one or more of aminosiloxanes, isocyanatosiloxanes, epoxysiloxanes and hydridosiloxanes; preferably an aminosiloxane; more preferably one or more of N-beta- (aminoethyl) -gamma-aminopropyltrimethoxysilane, N-beta- (aminoethyl) -gamma-aminopropyltriethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldimethoxysilane, N-beta- (aminoethyl) -gamma-aminopropylmethyldiethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-aminopropylmethyldimethoxysilane, gamma-aminopropylmethyldiethoxysilane;

the compound with the hydrophilic group and/or the potential hydrophilic group is selected from one or more of polyoxyethylene ether, amino acid, acrylic acid, acrylate, 1,4-buthanesulfonic lactone, 1,3-propane sultone, butyrolactone and propane lactone; the polyoxyethylene ether is preferably hydroxyl-terminated polyoxyethylene ether, epoxy polyoxyethylene ether, amino polyoxyethylene ether or allyl polyoxyethylene ether, and the compound with a hydrophilic group and/or a potential hydrophilic group is preferably one or more of hydroxyl-terminated polyoxyethylene ether, 1,4-butanesultone and 1,3-propanesultone.

The molar ratio of the added reactive functional groups of the siloxane ii) to the compound having hydrophilic groups and/or potentially hydrophilic groups is 2:1 to 1:4, preferably 1.2.

The component b) is a dihydric and/or polyhydric alcohol with the number average molecular weight of 20-15000; preferably from 60 to 5000 dihydric and/or polyhydric alcohols; more preferably one or more of polyesters having a functionality of 2 to 3 and a number average molecular weight of 400 to 5000, polycarbonates, polylactone polyols, polyether polyols, and small molecule alcohols having a functionality of 2 to 4 and a number average molecular weight of 60 to 400.

Suitable polyester polyols may be linear polyester diols and/or slightly branched polyester diols (which may contain small amounts of polyester polyols having a functionality of greater than 3) which may be obtained, for example, by dehydration condensation of polyols with carboxylic acids and/or anhydrides such as aliphatic, cycloaliphatic, aromatic dicarboxylic or polycarboxylic acids or their corresponding anhydrides, and the like, by known means, examples of which include, but are not limited to, succinic acid, methylsuccinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexane dicarboxylic acid, maleic acid, fumaric acid, trimellitic acid, phthalic anhydride, trimellitic anhydride, succinic anhydride, or mixtures thereof; the polyol to be subjected to the dehydration condensation is preferably a low molecular weight polyol (e.g., a polyol having a molecular weight of not more than 400), examples of which include, but are not limited to, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, 1,8-octanediol, 43 zxft 9843-decanediol, 1,12-dodecane diol, or a mixture of several thereof. Optionally, a polyhydric alcohol having a higher functionality, such as trimethylolpropane, glycerol or pentaerythritol, may also be added when the above-described dehydration condensation is carried out. Cycloaliphatic, aromatic polyols are also suitable as polyols for the preparation of the polyester polyols.

Preferably, the carboxylic acid or anhydride subjected to dehydration condensation is one or more of phthalic acid, isophthalic acid, terephthalic acid and adipic acid, and the polyhydric alcohol subjected to dehydration condensation is preferably one or more of ethylene glycol, butanediol, hexanediol and neopentyl glycol.

The polyester polyols may also be homopolymers or copolymers of lactones, obtainable by ring-opening reaction of lactones or mixtures of lactones with suitable di-and/or higher-functional low molecular weight polyols. Wherein the lactone is preferably butyrolactone, epsilon caprolactone, methyl-epsilon caprolactone and mixtures thereof, and the polyol may be a low molecular weight polyol as described above as a structural component of the polyester polyol, preferably a linear polyester polyol of epsilon caprolactone is ring-opened using butanediol, hexanediol, 2,2-dimethyl-1,3-propanediol or mixtures thereof.

The component b) can also be a polycarbonate polyol having hydroxyl groups prepared using a diol, which may be 1,4-butanediol or 1,6-hexanediol, and a carbonate, which may be a diaryl carbonate or a dialkyl carbonate. The diaryl carbonate comprises diphenyl carbonate and the dialkyl carbonate comprises dimethyl carbonate; preferably, the polycarbonate polyol is a polycarbonate polyol prepared by reacting 1,6-hexanediol with dimethyl carbonate.

The polyether polyol is selected from one or more of polypropylene oxide polyol, polyethylene oxide polyol, polytetrahydrofuran polyol, and copolymer polyol thereof.

The functionality of the small molecule alcohol of the component b) according to the invention having a molecular weight of 60 to 400 is 2 to 4, examples of suitable small molecule alcohols include, but are not limited to, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 24 zxft 4924-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dimethylolpropane, trimethylolpropane, pentaerythritol or mixtures thereof.

The polyisocyanates of component c) are organic compounds having at least two isocyanate groups, preferably diisocyanates. Suitable diisocyanates may be one or more of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4' -dicyclohexylmethane diisocyanate, 4,4' -dicyclohexylpropane diisocyanate, 1,4-benzene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4' -diphenylmethane diisocyanate, 2,2' -and 2,4' -diphenylmethane diisocyanate, tetramethylxylene diisocyanate and p-xylylene diisocyanate. Preferred are mixtures of one or more of hexamethylene diisocyanate, isophorone diisocyanate, 4,4' -dicyclohexylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate.

Polyisocyanates known in the art having a functionality of more than 3 isocyanate groups per molecule, such as polyisocyanates prepared by modification of simple aliphatic, cycloaliphatic, araliphatic and/or aromatic diisocyanates or modified polyisocyanates synthesized from at least two diisocyanates, for example having uretdione, isocyanurate, urethane, allophanate, biuret, carbodiimide, iminooxadiazinedione and/or oxadiazinetrione structures, may also be included in component c) in small amounts, preferably not more than 15% by weight of the total amount of component c).

In the present invention, the potentially ionic group in component d) refers to a functional group having a covalent bond, which can be converted into a corresponding salt by adding a neutralizing agent as the pH of the solution changes. Preferred potentially ionic groups include acid groups, which are carboxyl (-COOH) and/or sulfonic (-SO) groups ₃ H) (ii) a Preferred NCO-reactive groups are hydroxyl and/or amino groups.

Preferred ionic groups are carboxylate (-COO) ^- ) And/or sulfonate (-SO) ₃ ^- )。

Preferably, examples of component d) include, but are not limited to, one or more of dihydroxy carboxylic acids, trihydroxy carboxylic acids, dihydroxy sulfonic acids, trihydroxy sulfonic acids, diamino sulfonic acids, triamino sulfonic acids, diamino carboxylic acids, triamino carboxylic acids, salts thereof (alkali metal salts, alkaline earth metal salts, and/or ammonium salts), and the like.

Particularly preferably, component d) is one or more of the Michael (Michael) addition products formed by the addition of one or more of dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, dihydroxysuccinic acid, N- (2-aminoethyl) -2-aminoethanesulfonic acid, N- (3-aminopropyl) -3-aminopropanesulfonic acid, N- (2-aminoethyl) -3-aminopropanesulfonic acid, and salts thereof, and/or acrylic acid, methacrylic acid, maleic acid and fumaric acid to amines such as ethylenediamine, butanediamine, isophoronediamine and/or 8978 zx8978-hexanediamine.

If component d) contains a potentially ionic group, the neutralizing agent is preferably added to the composition before, during or after component d) is added to the composition. The neutralizing agent is added in an amount that makes part or all of the potentially ionic groups ionic. Suitable neutralizing agents are, for example, one or more of primary amines, secondary amines, tertiary amines, alkali metal compounds and alkaline earth metal compounds, preferred neutralizing agents are one or more of ethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, 2-amino-2-methyl-1-propanol, morpholine, N-methylmorpholine, dimethylisopropylamine, N-methyldiethanolamine, triethylamine, dimethylcyclohexylamine, ethyldiisopropylamine, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide and the like.

In general, the amount of neutralizing agent added is such that the degree of neutralization is at least 50%, preferably at least 70%, and not more than 150%, based on the total molar amount of acid groups introduced. It is understood by those skilled in the art that free neutralizing agents are present in the system in addition to the acid groups being neutralized to form ionic groups. The degree of neutralization is particularly preferably from 90 to 110%. Wherein the degree of neutralization = the molar amount of added neutralizing agent/the total molar amount of introduced acid groups.

More preferably, component d) is N- (2-aminoethyl) -2-aminoethanesulfonate and/or dimethylolpropionate.

Component e) according to the invention is an NCO-reactive, nonionically hydrophilicizing compound component, preferably a polyoxyethylene ether containing at least one hydroxyl or amino group, more preferably a polyoxyethylene ether containing only one hydroxyl or amino group, for example a methyl polyoxyethylene ether. Examples of initiators for making the polyoxyethylene ethers include, but are not limited to, saturated monoalcohols, unsaturated alcohols, aromatic alcohols, araliphatic alcohols, secondary monoamines and heterocyclic secondary amines, wherein the saturated monoalcohols can be one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomeric pentanols, hexanols, heptanols, octanols, nonanols, n-decanols, n-dodecanol, n-tetradecanol, n-hexadecanol, cyclohexanol, hydroxymethylcyclohexane or 3-ethyl-3-hydroxymethyloxacyclo; the unsaturated alcohol may be one or more of allyl alcohol, 1,1-dimethyl-allyl alcohol, or oleyl alcohol; the aromatic alcohol can be one or more of phenol, isomeric cresol or hydroxymethyl phenol; the araliphatic alcohol may be one or more of benzyl alcohol, anisyl alcohol, or cinnamyl alcohol; the secondary monoamine may be one or more of dimethylamine, diethylamine, dipropylamine, diisopropylamine, di-N-butylamine, diisobutylamine, bis (2-ethylhexyl) -amine, N-methylcyclohexylamine, N-methyldicyclohexylamine, N-ethylcyclohexylamine, or N-ethyldicyclohexylamine; the heterocyclic secondary amine may be one or more of morpholine, pyrrolidine or piperidinoethylpyrazole; preferred starters are saturated monoalcohols having up to 4 carbon atoms, methanol being particularly preferred as starter. Preferred is a monofunctional polyethoxy ether having a number average molecular weight of 200 to 8000 and an ethylene oxide number of 4 to 200, and more preferred is a polyethylene glycol monomethyl ether having a number average molecular weight of 500 to 3000 and an ethylene oxide number of 12 to 75.

Component f) according to the invention is a compound containing 1 to 3, preferably 2 to 3, NCO-reactive functional groups, which may be one or more of hydroxyl, primary and secondary amino groups. Preferably, at least one NCO-reactive functional group of component f) is a primary or secondary amino group. The component f) may be an aliphatic or cycloaliphatic primary or secondary monoamine such as ethylamine, diethylamine, isopropylamine, butylamine or cyclohexylamine, and also aminoalcohols which contain both amino and hydroxyl groups, such as ethanolamine, diethanolamine, N-methylethanolamine, diisopropanolamine, 1,3-diamino-2-propanol, N- (2-hydroxyethyl) ethylenediamine, N-bis (2-hydroxyethyl) ethylenediamine and 2-propanolamine, and also diamines and triamines, such as ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentylenediamine, 1,6-hexylenediamine, 1,7-heptylenediamine, 1,8-octylenediamine, 1,9-nonylenediamine, 1,10-decyldiamine, 4,4 '-diaminodicyclohexylmethane, N' -dimethyl-1,3-propylenediamine, N-benzylethylenediamine, N '-diphenylethylenediamine, N-methylethylenediamine, m-phenylenediamine, 1,3-cyclohexylenediamine, N' -dimethylethylenediamine, isophoronediamine, piperazine, 1,4-diaminocyclohexane and diethylenetriamine, and may also be specific amines, such as adipic acid dihydrazide, hydrazine. Mixtures of two or more of the above compounds may also be used.

Component f) according to the invention is preferably a mixture of isophoronediamine and N- (2-hydroxyethyl) ethylenediamine in a molar ratio of 0.5 to 10, more preferably 1 to 5:1, for example 2:1 or 4:1.

Component g) according to the invention may be a blocking agent or an unsaturated compound containing a polymerization-active group, as is customary in the art; the blocking agent can be removed by heating at a relatively high temperature, such as 130 ℃ or higher, and is preferably one or more of butanone oxime, dimethylpyrazole, caprolactam, malonate, triazole, dimethyl triazole, tert-butylbenzylamine and cyclopentanone carboxyethyl ester; the unsaturated compound containing a polymerization active group is preferably one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, pentaerythritol triacrylate, and products obtained by reacting monoepoxides, diepoxides and/or polyepoxides with hydroxyl functional groups of acrylic acid or methacrylic acid, wherein polyepoxides refer to oxides having more than three rings.

In the present invention, the aqueous dispersion of polyurethane or polyurethane-urea preferably has a solids content of 15 to 70wt%, more preferably 35 to 60 wt%; the pH of the dispersion is preferably from 4 to 11, more preferably from 5 to 10; the average particle diameter of the solid phase particles in the system is preferably 20 to 1000nm, more preferably 50 to 450nm.

The present invention also provides a process for the preparation of the above-described aqueous polyurethane or polyurethane-urea dispersions by reacting components b), c), d), e) and optionally g) in a one-stage or multi-stage reaction to form an isocyanate-terminated prepolymer and then reacting this prepolymer with component a) and optionally f) in a one-stage or two-stage reaction; or reacting components b), c), e) and optionally g) in one or more reaction stages to form an isocyanate-terminated prepolymer, which is then reacted in one or more reaction stages with components a), d) and optionally f), and is then dispersed or dissolved with water, wherein optionally solvents are used which can be removed partly or completely by distillation during or after the dispersion.

The preparation of the aqueous polyurethane or polyurethane-urea dispersions according to the invention can be carried out in one or more stages in homogeneous phase or, in the case of a multistage reaction, in the dispersed phase in partial reaction. The complete or partial polymerization is followed by a dispersing, emulsifying or dissolving step. Optionally, the latter dispersed phase may be further subjected to a step of polyaddition or modification.

All processes known from the prior art, such as the emulsifier shear dispersion process, the acetone process, the prepolymer mixing process, the melt emulsification process, the ketimine process and the solid spontaneous dispersion process or their derivatization processes, can be used for the preparation of the aqueous dispersions of polyurethanes or polyurethane-ureas described above. An overview of these methods can be found in Methoden der organischen Chemie (Houben-Weyl, erweiterung-und zur 4. Aufiage, vol. E20, H.Bartl and J.Falbe, stuttgart, new York, thieme 1987, p. 1671-1682); the melt emulsification method, prepolymer mixing method and acetone method are preferred; the acetone process is particularly preferred.

Suitable solvents may be acetone, butanone, tetrahydrofuran, methyl isobutyl ketone, dioxane, acetonitrile, dipropylene glycol dimethyl ether, 1-methyl-2-pyrrolidone, etc., and may be added in portions or at one time at the start of the reaction, during the reaction, or at any stage after the end of the reaction. Acetone and butanone are preferred, acetone being more preferred.

The ratio of the molar amount of isocyanate groups to the sum of the molar amounts of hydroxyl and amino groups used to prepare the aqueous polyurethane or polyurethane-urea dispersion of the invention is from 0.6 to 2.5, preferably from 1.0 to 1.85.

The conversion is usually monitored by tracking the NCO content of the reaction mixture. For this purpose, spectroscopic measurements (for example determination of infrared or near-infrared spectra, refractive index) and chemopotentiometric titrations (for example chemical titrations via removal of a sample), preferably chemopotentiometric titrations, can be carried out.

The catalyst may be used in batch or in one-shot form at any stage during, or after the reaction, and may be any catalyst known to those skilled in the art for accelerating the reaction of NCO with OH, such as triethylamine, 1,4-diazabicyclo- [2,2,2] -octane, dibutyltin dilaurate, zinc isooctoate, bismuth isooctoate, zinc neodecanoate and bismuth neodecanoate, dibutyltin oxide, tin bis- (2-ethylhexanoate), and the like. Bismuth neodecanoate and bismuth isooctanoate are preferable, and bismuth neodecanoate is more preferable.

The chain extension reaction is generally carried out at a temperature of from 10 to 100 c, preferably from 25 to 60 c.

The organic solvent optionally used, for example acetone, is distilled off during and/or after the dispersion.

The aqueous dispersion of the present invention can be used in the fields of preparing coating agents, adhesives, sealants, etc.

The polyurethanes or polyurethane-ureas described herein are prepared by modification of silicones having hydrophilic groups. Since the siloxane used has a hydrophilic group, under the traction of the hydrophilic group during the formation of the aqueous dispersion, the siloxane can migrate to the surface of the latex particle and hydrolyze to form a silicon hydroxyl group. In the drying and activating processes, the siloxane on the surface of the latex particles is easy to hydrolyze and crosslink mutually, the crosslinking density is increased, the heat resistance, the humidity resistance and the like of the adhesive obtained by the method can be obviously improved by only adding a small amount of siloxane components, and the activation performance is prevented from being poor due to the introduction of a large amount of siloxane components.

Compared with the existing waterborne polyurethane-polyurea, the aqueous dispersion prepared by the hydrophilic silane modification of the invention is used as an adhesive, and has excellent initial heat resistance, later heat resistance and wet-heat hydrolysis resistance. The existing aqueous polyurethane-polyurea dispersoid needs to be added with a cross-linking agent such as isocyanate or carbodiimide before use, needs to be mixed according to the proportion before construction, has complex operation, and the prepared glue has short opening time and needs to be used in a specified time. The aqueous dispersion can meet the performance requirement without adding additional cross-linking agents such as isocyanate or carbodiimide, can be used as a single-component product, is simple to operate and long in opening time, and greatly improves the construction efficiency.

The aqueous dispersion siloxane of the invention has small addition amount and good stability of the aqueous dispersion. The compound system based on the epoxy resin has excellent stability and long storage time, and is suitable for preparing high-quality paint and sealant, especially adhesive.

The aqueous dispersions of polyurethanes or polyurethane-ureas prepared according to the invention can be used alone or together with auxiliary substances and additives known from coatings and adhesives technology. Such as emulsifiers, light stabilizers, such as UV absorbers and sterically Hindered Amines (HALS), antioxidants, fillers, antisettling agents, antifoaming and/or wetting agents, flow regulators, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, pigments, dyes, matting agents, adhesion promoters (Tackifier) and the like. The additives and/or auxiliaries can be added before/after the polymerization or after the dispersion.

The aqueous dispersions of polyurethanes or polyurethane-ureas prepared according to the invention can also be used in combination with other aqueous or solvent-containing oligomers or polymers, for example, polyethylene, polyvinyl alcohol, polyvinyl esters, polyvinyl ethers, polyvinyl chloride, polystyrene, polybutadiene, polyurethanes, polyurethane-polyureas, polyurethane-polyacrylates, polyesters, polyacrylates and/or copolymers dispersions or emulsions or aqueous or organic solutions. The compatibility of such mixtures must be tested in each case using simple preliminary tests.

The aqueous dispersions of polyurethanes or polyurethane-ureas prepared according to the invention and the adhesives or binder combinations based thereon are suitable for bonding any substrates, for example all types of metals, alloys, wood-based materials, particle board, ceramics, stone, concrete, asphalt, hard fibers, glass fibers, carbon nanotubes, leather, textiles and other inorganic materials. They are also suitable for bonding rubber materials such as natural and synthetic rubbers, various plastics such as polyurethane, polyvinyl acetate, polyvinyl chloride, etc. The same applies to thermoplastics such as ABS (acrylic-butadiene-styrene), PC (polycarbonate), polyolefin plastics and mixtures thereof.

The aqueous dispersions according to the invention can be used to prepare coating agents, adhesives and/or sealants by techniques known from coating technology or adhesive technology and to be used in these fields.

At the same time, the preparation method of the self-crosslinking aqueous polyurethane or polyurethane-urea dispersion of the invention is simple and easy.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are shown in the examples, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

2. The raw material sources are as follows:

PBA1000: polyadipic acid-1,4-butanediol ester diol, OH number =112mg KOH/g, purchased from Wanhua chemical group, inc., product designation WHP-104;

PBA2000: polyadipic acid-1,4-butanediol ester diol, OH number =56mg KOH/g, purchased from Wanhua chemical group, inc., product designation WHP — 204;

PBA4000: polyadipic acid-1,4-butanediol ester diol, OH number =28mg KOH/g, purchased from Wanhua chemical group, inc., product designation WHP — 404;

PPG2000: polyoxypropylene diol, OH number =56mg KOH/g, purchased from Shandong Lanxingdong chemical industry, inc., product designation DL2000D;

HDI: purchased from the Wanhua chemical group, inc., product brand:

HDI；

IPDI: purchased from the Wanhua chemical group, inc., product brand:

IPDI；

TDI-80: purchased from the Wanhua chemical group, inc., product brand: WANNATE TDI-80;

MPEG1200: polyethylene glycol monomethyl ether, number average molecular weight 1200g/mol, purchased from waukee;

mer N120: difunctional polyether, trimethylolpropane polyethylene glycol monomethyl ether, number average molecular weight 1000g/mol, purchased from boston;

PEG1000: bifunctional polyethers, polyethylene glycol, number average molecular weight 1000g/mol, purchased from national medicine reagents;

isocyanatopropyltrimethoxysilane: purchased from mai chart, brand a-Link 35;

n- (β -aminoethyl) - γ -aminopropyltriethoxysilane: purchased from a national medicine reagent, with purity of 97%;

1,3-propane sultone: purchased from aladine reagent, 99% pure;

silane I: 51.25g (0.25 mol) of isocyanatopropyltrimethoxysilane and 500g (0.5 mol) of PEG1000 are uniformly mixed, 0.01g of dibutyltin dilaurate is dropwise added, the temperature is increased to 75 ℃, timing is started, the temperature is kept for 4 hours, the NCO content is tested to be 0.02%, and the mixture is collected for standby.

Silane II: 36g (0.5 mol) of acrylic acid is dripped into a 500ml three-neck flask filled with 179.3g (1 mol) of 3-aminopropyltrimethoxysilane, dripping is finished for 30min, and after dripping is finished, heat preservation is carried out for 12h at 50 ℃ to obtain silane II.

Silane III: adding 8.9g (0.1 mol) of alanine into 100g of dimethylformamide, stirring and heating to 50 ℃, preserving heat, slowly dropwise adding 23.6g (0.1 mol) of gamma- (2,3-glycidoxy) propyl trimethoxy silane, finishing dropping for 30min, and preserving heat for 12h at 50 ℃ after finishing dropping to obtain a dimethylformamide solution of silane III with the mass fraction of 24.5%.

Silane IV: 26.4g (0.1 mol) of N- (beta-aminoethyl) -gamma-aminopropyltriethoxysilane is added into 200ml of ethyl acetate, stirred and heated to 50 ℃, and then heat preservation is carried out, 12.2g (0.1 mol) of 1,3-propane sultone is dripped in, and dripping is finished within 30 min. During the dropwise addition, a large amount of white solid precipitated. After the dropwise addition, the mixture is kept at 60 ℃ for 1h, then cooled to 5 ℃ and kept at the temperature for 12h, then filtered, washed with ethyl acetate at 5 ℃ for three times, and dried in vacuum at 50 ℃ to obtain 34.93g of a white powdery product with the yield of 90.5%.

Example 1

280g of dehydrated polyester PBA2000, 20g of dehydrated polyether PPG2000, 72g of TDI-80, 1g of dehydrated MPEG1200, 12g of 1, 4-butanediol, 9g of dimethylolpropionic acid, 5g of silane I, 60g of acetone were placed in a 1L four-necked round-bottomed flask equipped with a nitrogen inlet and outlet, and the mixture was stirred at 70 ℃ until NCO reached 1.11%. The prepolymer was dissolved in 425g of acetone and cooled to 35 ℃ and then neutralized with 5.4g of triethylamine and stirred for 5min, after which the mixture was dispersed by adding 500g of water. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. A solvent-free aqueous polyurethane-polyurea dispersion was obtained having a solids content of 45% by weight and an average particle diameter of 240nm, determined by laser correlation (laser granulometer) in the dispersed phase.

Example 2

300g of dehydrated PBA2000, 5g of dehydrated MPEG1200, 14g of dehydrated YMR 120, 38.5g of HDI, 48g of acetone, 0.04g of bismuth neodecanoate were charged into a 1L four-necked round-bottomed flask equipped with a nitrogen inlet/outlet, and the mixture was stirred at 80 ℃ until NCO reached 1.44%. The prepolymer was dissolved in 494g of acetone and cooled to 50 ℃. 20g of an aqueous solution containing 0.4g N- (2-aminoethyl) -2-aminoethanesulfonic acid sodium salt 3g IPDA and 0.3g hydroxyethylethylenediamine was added to the acetone solution in which the prepolymer was dissolved while vigorously stirring. After 5min 1g of silane II were added and vigorous stirring was continued for 15min, after which the mixture was dispersed by adding 346g of water and, after dispersion, neutralized by adding 0.4g of triethylamine. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 are added and water is added to adjust the solids content. A solvent-free aqueous polyurethane-polyurea dispersion is obtained having a solids content of 50% by weight and an average particle diameter of 230nm in the dispersed phase, determined by laser correlation.

Example 3

300g of dehydrated PBA4000, 5g of dehydrated MPEG1200, 21g of HDI, 46g of acetone, 0.04g of bismuth neodecanoate were added to a 1L four-necked round-bottomed flask equipped with a nitrogen inlet and outlet, and the mixture was stirred at 90 ℃ until NCO reached 1.14%. The prepolymer was dissolved in 614g of acetone and cooled to 50 ℃ and 1.92g of butanone oxime was added and the temperature was maintained for 1h. 15g of an aqueous solution in which 1.5g N- (2-aminoethyl) -2-aminoethanesulfonic acid sodium salt, 0.1g of IPDA and 0.2g of hydroxyethylethylenediamine were dissolved was added to an acetone solution in which the prepolymer was dissolved, while vigorously stirring the mixture. After 5min, 1.22g of a 24.5% strength by mass solution of silane III in dimethylformamide are added and vigorous stirring is continued for 15min, after which the mixture is dispersed by adding 258g of water and, after dispersion, neutralized by adding 0.08g of triethylamine. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. A solvent-free aqueous polyurethane-polyurea dispersion was obtained having a solids content of 55% by weight and an average particle diameter of 310nm in the dispersed phase, determined by laser correlation.

Example 4

300g of dehydrated polyester PBA1000, 131.3g of IPDI, 0.2g of dehydrated Ymer120, 0.1g of pentaerythritol, 23.7g of dimethylolpropionic acid, 4g of silanI, 77g of acetone and 0.04g of bismuth neodecanoate were placed in a 1L four-neck round-bottomed flask equipped with a nitrogen inlet and outlet and the mixture was stirred at 70 ℃ until the NCO reached 1.74%. The prepolymer was dissolved in 393g of acetone and cooled to 35 ℃, then 9.4g of triethylamine was added for neutralization and stirring for 5min, then the mixture was dispersed by adding 571g of water, 12g of an aqueous solution in which 2.37g of ethylenediamine was dissolved was added to the dispersion after the dispersion was completed, and stirring was continued for 5min. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. An aqueous dispersion of solvent-free polyurethane-polyurea was obtained having a solids content of 45% by weight and an average particle diameter of 180nm as determined by laser correlation (laser granulometer) in the dispersed phase.

Example 5

200g of dehydrated PBA4000, 100g of dehydrated PBA1000, 5g of dehydrated MPEG1200, 21g of HDI, 21g of IPDI, 49g of acetone, 0.04g of bismuth neodecanoate were placed in a 1L four-necked round-bottomed flask equipped with a nitrogen inlet and outlet, and the mixture was stirred at 70 ℃ until the NCO reached 1.51%. The prepolymer was dissolved in 483g of acetone and cooled to 50 ℃. An aqueous solution of 35g in which 2.5g of sodium N- (2-aminoethyl) -2-aminoethanesulfonate, 0.8g of IPDA and 0.8g of hydroxyethylethylenediamine were dissolved was added to an acetone solution in which the prepolymer was dissolved, and the mixture was vigorously stirred. After 5min 1g of silane IV was added and vigorous stirring was continued for 15min, after which the mixture was dispersed by adding 400g of water. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. An aqueous dispersion of a solvent-free polyurethane-polyurea was obtained having a solids content of 45% by weight and an average particle diameter of 150nm as determined by laser correlation in the dispersed phase.

Example 6

300g of dehydrated polyester PBA2000, 70g of TDI-80, 1g of dehydrated MPEG1200, 10g of 1, 4-butanediol, 9g of dimethylolpropionic acid, 15g of silane I, 60g of acetone, and 0.04g of bismuth neodecanoate were charged into a 1L four-necked round-bottomed flask equipped with a nitrogen inlet/outlet, and the mixture was stirred at 60 ℃ until NCO reached 1.22%. The prepolymer was dissolved in 435g of acetone and cooled to 35 ℃, then 5.4g of triethylamine was added for neutralization and stirring for 5min, then the mixture was dispersed by adding 760g of water, after the dispersion was complete 15g of an aqueous solution in which 3g of ethylenediamine was dissolved was added to the dispersion, and stirring was continued for 5min. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. A solvent-free aqueous polyurethane-polyurea dispersion was obtained having a solids content of 35% by weight and an average particle diameter of 40nm, determined by laser correlation (laser granulometer) in the dispersed phase.

Example 7

300g of dehydrated polyester PBA1000, 137g of IPDI, 2g of dehydrated MPEG1200, 6g of dimethylolpropionic acid, 4g of silane I and 0.04g of bismuth neodecanoate were placed in a 1L four-necked round bottom flask equipped with a nitrogen inlet and outlet and the mixture was stirred at 70 ℃ until the NCO reached 4.38%. The prepolymer was dissolved in 147g of acetone and cooled to 50 ℃ and 10g of butanone oxime were added and the reaction continued until the NCO reached 3.38%. The prepolymer was cooled to 35 ℃, 4.5g of triethylamine was then added to neutralize and stir for 5min, the mixture was then dispersed by adding 326g of water, 170g of an aqueous solution in which 32g of ipda and 1g of hydroxyethylethylenediamine were dissolved was added to the dispersion after dispersion was complete, and stirring was continued for 5min. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. A solvent-free aqueous polyurethane-polyurea dispersion is obtained having a solids content of 50% by weight and an average particle diameter of 520nm, determined by laser correlation (laser granulometer) in the dispersed phase.

Comparative example 1

200g of dehydrated PBA4000, 100g of dehydrated PBA1000, 5g of dehydrated MPEG1200, 21g of HDI, 21g of IPDI, 49g of acetone, 0.04g of bismuth neodecanoate were placed in a 1L four-necked round-bottomed flask equipped with a nitrogen inlet and outlet, and the mixture was stirred at 70 ℃ until the NCO reached 1.51%. The prepolymer was dissolved in 483g of acetone and cooled to 50 ℃. An aqueous solution of 35g in which 2.5g of sodium N- (2-aminoethyl) -2-aminoethanesulfonate, 0.8g of IPDA and 0.8g of hydroxyethylethylenediamine were dissolved was added to an acetone solution in which the prepolymer was dissolved, and the mixture was vigorously stirred. After 5min 1g N- (. Beta. -aminoethyl) -gamma. -aminopropyltriethoxysilane was added and vigorous stirring continued for 15min, after which the mixture was dispersed by addition of 400g water. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. A solvent-free aqueous polyurethane-polyurea dispersion was obtained having a solids content of 45% by weight and an average particle diameter of 170nm in the dispersed phase, determined by laser correlation.

Comparative example 2

200g of dehydrated PBA4000, 100g of dehydrated PBA1000, 5g of dehydrated MPEG1200, 21g of HDI, 21g of IPDI, 49g of acetone, 0.04g of bismuth neodecanoate were placed in a 1L four-necked round-bottomed flask equipped with a nitrogen inlet and outlet, and the mixture was stirred at 70 ℃ until the NCO reached 1.51%. The prepolymer was dissolved in 483g of acetone and cooled to 50 ℃.5g of a 50% aqueous solution of sodium N- (2-aminoethyl) -2-aminoethanesulfonate and 0.6g of IPDA in 35g of an aqueous solution were added to an acetone solution containing the prepolymer and vigorously stirred. After 5min 2.5g N- (. Beta. -aminoethyl) -gamma. -aminopropyltriethoxysilane was added and vigorous stirring was continued for 15min, after which the mixture was dispersed by addition of 400g water. After separation of the acetone by distillation, 4g of the emulsifier Tween 20 were added and the solids content was adjusted by addition of water. A solvent-free aqueous polyurethane-polyurea dispersion was obtained having a solids content of 45% by weight and an average particle diameter of 190nm in the dispersed phase, determined by laser correlation.

Preparation of the adhesive

100g of the aqueous dispersion, 0.05g of BYK024 (Beck chemical) were mixed and stirred at 500rpm for 5min, 0.2g of Tego245 (digao) was added and stirred for a further 5min, then 0.15g of Vesmody U604 (Vawawa chemical) was added and stirred at 600rpm for 10min.

Preparation of the samples

Samples were prepared using substrate a (rubber), substrate B (canvas), and substrate C (PVC), respectively.

(1) Two pieces of substrate a were first treated with a treating agent (acetone solution of trichloroisocyanurate, 2 wt%), and then air-dried for use. The adhesive was then thinly applied using a brush to a 2.5cm wide and 15cm long strip of substrate and dried in an oven at 65 ℃ for 5 minutes, after which it was removed at 30kg/cm ² Pressing for 10 seconds to obtain the composite material A.

(2) Composite materials B and C were prepared in the same manner as in step (1).

Testing the peel strength of the composite:

the peel strength was measured with a GOTECH tensile machine at a peel rate of 200 mm/min.

Initial strength: and after pressing, directly testing the peel strength of the laminated board by a tensile machine.

Later strength: after the test piece was left at room temperature for 24 hours, the peel strength was measured.

The test results are shown in Table 1.

TABLE 1 Peel Strength of adhesives on different substrates

The "examples" and "comparative examples" in the above table mean that an adhesive was prepared using the aqueous dispersion prepared in the corresponding examples or comparative examples as a raw material.

As can be seen from Table 1, the one-component adhesive based on the hydrophilic silicone-modified polyurethane-polyurethane urea dispersion provided by the present invention (example 5) has significantly improved initial strength and later strength compared to the one-component adhesive based on the conventional silicone-modified polyurethane-polyurethane urea dispersion (comparative example 1), and a larger amount of conventional silicone needs to be added for modification to obtain the same strength properties (comparative example 2).

Heat resistance of test specimens:

initial heat resistance: the prepared test piece is hung with a weight of 500g and placed in an oven at 80 ℃, and the length of the test piece pulled apart within 30 minutes is tested.

And (3) later-stage heat resistance: the prepared test piece is placed at room temperature for 3 days, a weight of 1 kg is hung, the test piece is placed in a 70 ℃ oven, and the length of the test piece pulled open within 24 hours is tested.

Moisture and heat resistance: the prepared test piece is placed at room temperature for 3 days, a weight of 500g is hung, and the test piece is placed in an oven with the temperature of 70 ℃ and the humidity of 95 percent to test the pulling length of the test piece within 24 hours.

The test results are shown in Table 2.

TABLE 2 Heat resistance of adhesives on different substrates

As seen from Table 1, the one-pack adhesive based on the hydrophilic siloxane-modified polyurethane-polyurethane urea dispersion provided by the present invention (example 5) has significantly improved initial strength, later heat resistance and wet heat resistance, compared to the one-pack adhesive based on the conventional siloxane-modified polyurethane-polyurethane urea dispersion (comparative example 1), mainly because the siloxanes on the surface of the latex particles are more likely to be hydrolyzed and cross-linked with each other, the cross-linking density of the coating film is significantly increased, the heat resistance and wet heat resistance of the coating film are significantly improved, and a larger amount of conventional siloxane is required for modification to obtain the same heat resistance and wet heat resistance (comparative example 2).

Activation temperature of test specimen:

the dispersions prepared in example 5 and comparative example 2 were each knife-coated to a wet film thickness of 150 μm to a high-density fiberboard, the high-density fiberboard and PVC were simultaneously placed in an oven at a certain temperature, and after baking for 10min, whether the PVC tape could be adhered to the high-density fiberboard was observed, and the lowest temperature at which adhesion could be achieved, i.e., the activation temperature, was recorded.

The test results were as follows: the activation temperatures of the dispersions prepared in example 5 and comparative example 2 were 55 ℃ and 60 ℃, respectively, i.e., the activation temperature of the polyurethane or polyurethane-urea aqueous dispersion prepared by modifying with hydrophilic siloxane could be kept low while achieving the same heat resistance and humidity resistance.

Claims

1. An aqueous polyurethane-polyurea dispersion, characterized in that the polyurethane-polyurea is the reaction product obtained by reacting a composition comprising:

a) At least one component of a siloxane i) having the formula:

wherein the group R contains at least one isocyanate reactive group and at least one hydrophilic group, and at least one of R1, R2 and R3 is methoxy or ethoxy;

b) At least one polyol component having a functionality of 2 to 4;

c) At least one polyisocyanate component;

d) At least one component of hydrophilic compound, the hydrophilic group of the hydrophilic compound comprises one or two of ionic group and potential ionic group, the hydrophilic compound contains 2-3 isocyanate reactive groups; e) Optionally, a component of an isocyanate-reactive nonionic hydrophilic compound;

f) Optionally, a compound containing 1 to 3 NCO-reactive functional groups;

g) Optionally, other isocyanate-reactive compounds.

2. The aqueous dispersion according to claim 1, wherein component a) is used in an amount of 0.05 to 4 wt.%, based on the total solids weight of the composition; the amount of the component b) is 60 to 92wt percent; the amount of the component c) is 6 to 30 weight percent; the amount of the component d) is 0.2 to 5.5 weight percent; the amount of the component e) is 0 to 6 weight percent; the amount of the component f) is 0 to 7 weight percent; the amount of component g) is 0 to 2 wt.%.

3. The aqueous dispersion according to claim 2, wherein the component a) is used in an amount of 0.2 to 2.5 wt.%, based on the total solids weight of the composition; the amount of the component b) is 75 to 90 weight percent; the amount of the component c) is 8-20 wt%; the amount of the component d) is 1 to 3 weight percent; the amount of the component e) is 0.5 to 3 weight percent; the amount of the component f) is 0.5 to 3 weight percent; the amount of component g) is 0 to 2 wt.%.

4. The aqueous dispersion according to claim 1 or 2, wherein the hydrophilic groups of the siloxane i) are selected from one or more of ionic groups, potentially ionic groups and non-ionic groups; the ionic group is a carboxylate and/or a sulfonate; the potential ionic group is carboxyl and/or sulfonic group; the nonionic group is polyoxyethylene ether.

5. The aqueous dispersion of claim 1, wherein the isocyanate-reactive groups of siloxane i) comprise one or both of hydroxyl and secondary amino groups.

6. The aqueous dispersion according to claim 1, wherein the siloxanes i) are obtainable by reacting siloxanes ii) with compounds having hydrophilic and/or potentially hydrophilic groups;

the molar ratio of siloxane ii) to compound having hydrophilic and/or potentially hydrophilic groups added is: 2:1-1:4.

7. The aqueous dispersion according to claim 6, wherein the siloxane ii) is added in a molar ratio to the compound having hydrophilic groups and/or potentially hydrophilic groups of 1.2.

8. A dispersion according to claim 6, wherein the siloxane ii) is selected from one or more of aminosiloxanes, isocyanatosiloxanes, epoxysiloxanes and hydrosiloxanes.

9. The dispersion according to claim 8, wherein the siloxane ii) is an aminosiloxane.

10. The dispersion according to claim 9, wherein the siloxane ii) is one or more of N- β - (aminoethyl) - γ -aminopropyltrimethoxysilane, N- β - (aminoethyl) - γ -aminopropyltriethoxysilane, N- (β -aminoethyl) - γ -aminopropylmethyldimethoxysilane, N- β - (aminoethyl) - γ -aminopropylmethyldiethoxysilane, γ -aminopropyltrimethoxysilane, γ -aminopropyltriethoxysilane, γ -aminopropylmethyldimethoxysilane, γ -aminopropylmethyldiethoxysilane.

11. The aqueous dispersion according to claim 6, wherein the compound having hydrophilic and/or potentially hydrophilic groups is selected from one or more of the group consisting of polyoxyethylene ether, amino acids, acrylic acid, acrylates, 1,4-butanesultone, 1,3-propanesultone, butyrolactone and propiolactone.

12. The aqueous dispersion according to claim 11, wherein said polyoxyethylene ether is a hydroxyl-terminated polyoxyethylene ether, an epoxy-terminated polyoxyethylene ether, an amino-terminated polyoxyethylene ether, or an allyl-terminated polyoxyethylene ether.

13. The aqueous dispersion according to claim 11, wherein the compound having hydrophilic and/or potentially hydrophilic groups is selected from one or more of the group consisting of hydroxy-terminated polyoxyethylene ether, 1,4-butanesultone, 1,3-propanesultone.

14. The aqueous dispersion according to claim 1, wherein component b) is a polyol having a number average molecular weight of 20 to 15000.

15. The aqueous dispersion of claim 14, wherein component b) is a polyol of 60 to 5000.

16. The aqueous dispersion according to claim 15, wherein component b) is one or more of polyesters with a functionality of 2 to 3 having a number average molecular weight of 400 to 5000, polycarbonates, polylactone polyols, polyether polyols and small molecule alcohols with a functionality of 2 to 4 having a number average molecular weight of 60 to 400.

17. Aqueous dispersion according to claim 1, wherein the polyisocyanate of component c) is an organic compound having at least two isocyanate groups.

18. The aqueous dispersion according to claim 17, wherein the polyisocyanate of component c) is a diisocyanate; the diisocyanate is selected from one or more of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4' -dicyclohexylmethane diisocyanate, 4,4' -dicyclohexylpropane diisocyanate, 1,4-benzene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4' -diphenylmethane diisocyanate, 2,2' -and 2,4' -diphenylmethane diisocyanate, tetramethylxylene diisocyanate and p-xylylene diisocyanate.

19. An aqueous dispersion according to claim 1, wherein the hydrophilic groups of the hydrophilic compound are carboxylate and/or sulfonate groups; the potential ionic group is carboxyl and/or sulfonic group; the isocyanate reactive groups are hydroxyl and/or amino groups.

20. The aqueous dispersion according to claim 19, wherein the hydrophilic compounds containing ionic and/or potentially ionic groups in component d) comprise one or more of dihydroxycarboxylic acid, trihydroxycarboxylic acid, dihydroxysulfonic acid, trihydroxysulfonic acid, diaminosulfonic acid, triamino sulfonic acid, diaminocarboxylic acid, triamino carboxylic acid, and salts thereof.

21. The aqueous dispersion according to claim 20, wherein the hydrophilic compounds containing ionic and/or potentially ionic groups in component d) are selected from the group consisting of dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, dihydroxysuccinic acid, N- (2-aminoethyl) -2-aminoethanesulfonic acid, N- (3-aminopropyl) -3-aminopropanesulfonic acid, N- (2-aminoethyl) -3-aminopropanesulfonic acid and salts thereof or michael addition products formed by the addition of one or more of acrylic acid, methacrylic acid, maleic acid and fumaric acid to amines.

22. The aqueous dispersion according to claim 1, wherein component e) is selected from the group consisting of polyoxyethylene ethers containing at least one hydroxyl or amino group.

23. The aqueous dispersion according to claim 22, wherein component e) is selected from the group consisting of polyoxyethylene ethers containing only one hydroxyl or amino group.

24. The aqueous dispersion according to claim 22 or 23, wherein said polyoxyethylene ether has an ethylene oxide number of 4 to 200 per molecule.

25. The aqueous dispersion according to claim 24, wherein said polyoxyethylene ether has an ethylene oxide number per molecule of 12 to 75.

26. The aqueous dispersion according to claim 24, wherein component e) is a polyoxyethylene ether having a number average molecular weight of 200 to 8000 and an ethylene oxide number of 4 to 200.

27. The aqueous dispersion according to claim 25, wherein component e) is a polyethylene glycol monomethyl ether having a number average molecular weight of 500 to 3500 and an ethylene oxide number of 12 to 75.

28. Aqueous dispersion according to claim 1, wherein component f) is a compound containing 1 to 3 amino and/or hydroxyl groups.

29. The aqueous dispersion according to claim 28, wherein at least one NCO-reactive functional group of component f) is a primary or secondary amino group.

30. The aqueous dispersion according to claim 29, wherein component f) is a mixture of isophorone diamine and N- (2-hydroxyethyl) ethylene diamine in a molar ratio of 0.5 to 10.

31. The aqueous dispersion of claim 30, wherein component f) is a mixture of isophorone diamine and N- (2-hydroxyethyl) ethylene diamine of 1 to 5:1.

32. A process for preparing an aqueous dispersion according to any of claims 1 to 31, comprising the steps of: reacting components b), c), d), e) and optionally g) in one or more reaction stages to form an isocyanate-terminated prepolymer, then reacting this prepolymer with components a) and optionally f) in one or two reaction stages, and then dispersing or dissolving with water, wherein optionally a solvent is used which can be partially or completely removed by distillation during or after the dispersion; alternatively, the first and second electrodes may be,

reacting components b), c), e) and optionally g) in one or more reaction stages to form an isocyanate-terminated prepolymer, then reacting this prepolymer with components a), d) and optionally f) in one or more reaction stages, and then dispersing or dissolving with water, wherein optionally a solvent is used which can be partially or completely removed by distillation during or after the dispersing.

33. Use of the aqueous dispersion according to any of claims 1 to 31 or the aqueous dispersion prepared by the process according to claim 32 for the preparation of coating agents, adhesives, sealants.