Ionic liquid type waterborne polyurethane dispersion, and preparation method therefor and use thereof

Abstract

Disclosed in the present application is an ionic liquid type waterborne polyurethane dispersion, which is characterized in that a cationic waterborne polyurethane dispersion is obtained by grafting a cationic liquid to a waterborne polyurethane resin main body by means of a chemical reaction, wherein the cationic liquid is derived from an ionic liquid alcohol. Further provided in the present application are a preparation method for and the use of the ionic liquid type waterborne polyurethane dispersion. In the present application, the cationic liquid is grafted to the waterborne polyurethane resin main body by means of a chemical reaction, thereby solving the problems of low conductivity and a low lithium ion transference number of a polymer-based electrolyte.

Description

An ionic liquid type aqueous polyurethane dispersion and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of lithium battery solid electrolytes, and in particular to an ionic liquid type aqueous polyurethane dispersion and a preparation method and application thereof. Background Art

[0002] Lithium metal, with its high theoretical capacity and low redox potential, has attracted widespread attention in the battery field. However, conventional electrolytes pose safety concerns such as localized overheating and thermal runaway during charge and discharge. Solid-state electrolytes can effectively address these issues. Currently, polymer-based electrolytes, due to their flexibility and processability, have been widely adopted in solid-state batteries, but they still suffer from issues such as low conductivity and low ion transference numbers.

[0003] Traditional solid-state electrolytes, such as polyethylene oxide (PEO), typically exhibit low electrical conductivity or a low metal ion transport coefficient (approximately 0.2) due to the strong coordination of metal ions with polar groups in the polymer backbone. To address this issue, various polymer structures have been designed and proposed to enhance metal ion transport and transference numbers. For example, the introduction of loosely coordinated repeating units (e.g., polycarbonate, polyester, or polytetrahydrofuran) can weaken the coordination of metal ions with the polymer backbone, increasing the transference number of Li+ or Na+. Designing polymers that restrict anion movement can also increase the transference number of lithium ions. Alternatively, block copolymers or cross-linked polymer chains can be used to enhance ionic conductivity. In recent years, polyionic liquids (PILs), whose monomers are polymerizable ionic liquid cations, have emerged as promising solid-state solvents for lithium salts and exhibit promising performance. However, they also present safety issues such as leakage. Furthermore, due to their unique lithium-anion-polycation co-coordination structure, the ionic conductivity of these materials increases with increasing salt concentration even at low salt concentrations. This is in stark contrast to traditional solid electrolytes, where the coordination effect dominates at low concentrations, resulting in a negative correlation between conductivity and salt concentration. These limitations have been addressed by using PEO (polyethylene oxide)-based solid polymer electrolytes (SPEs) as modifiers. HACC-TFSI (polysaccharide quaternary ammonium salt polyionic liquid) hybrid SPEs exhibit an expanded amorphous region and enhanced ionic conductivity. The interaction between the quaternary ammonium salt cations and the TFSI- anions in the hybrid SPEs promotes the dissociation of Li+ and TFSI-, further improving ion mobility. Furthermore, the hybrid SPEs exhibit superior electrochemical stability, mechanical strength, and thermal stability compared to blank SPEs without HACC-TFSI.

[0004] Waterborne polyurethane resin is a copolymer composed of hard segments and soft segments, with adjustable hardness and softness. The hard segment is mainly composed of groups such as strongly polar and rigid urethane groups. Due to the large cohesive energy, hydrogen bonds can be formed between molecules, and they gather together to form hard segment microphase regions. The soft segment is mainly composed of macromolecular diols, which promotes the formation of a larger free volume of waterborne polyurethane. Although the soft segment and the hard segment have a certain degree of miscibility, the hard segment phase region and the soft segment phase region are thermodynamically incompatible, resulting in microphase separation, and the soft segment microregion and the hard segment microregion exhibit their own glass transition temperature, thereby providing excellent transmission channels for ions.

[0005] Chinese patent CN107394264B discloses a high-temperature resistant aqueous polyurethane solid electrolyte and its preparation method. The polymer solid electrolyte prepared by the invention has high ionic conductivity, high temperature resistance and excellent thermal stability. It also has good dimensional stability and high-temperature ionic conductivity under high temperature conditions of 140°C. However, the invention uses polyisosorbide terephthalate polyester diol and polyethylene glycol as soft segments and isocyanate as initiator, and forms an aqueous polyurethane resin through conventional chain extenders and then mechanically mixes it with lithium salt to form a solid electrolyte. It mainly uses polyethylene glycol as a hydrophilic component and transmission channel, and its conductivity is very limited. In the medium and low temperature range, the conductivity is lower than that of the product using polyethylene glycol as the initiator alone. It is difficult to effectively solve the ionic conductivity problem and does not have universal applicability; Chinese patent CN115612166A discloses a water-based An alkaline solid electrolyte of polyurethane ion-conducting polymer composite foam and a preparation method thereof. The invention adopts a chemical foaming method, introduces an ion-conducting polymer with an aqueous polyurethane foam as a skeleton, and soaks it in an alkaline solution to obtain an alkaline solid electrolyte based on aqueous urethane / ion-conducting polymer composite foam. The ion-conducting polymer serves as an ion transport carrier, forming an ion transport path in the aqueous polyurethane foam, thereby enabling the material to obtain excellent comprehensive performance, so that the electrolyte not only has excellent mechanical properties and good resilience, but also has good stability under alkaline conditions; at the same time, the alkaline solid electrolyte prepared by the present invention has low volume resistivity and high room temperature conductivity. However, the invention adopts dihydroxymethylbutyric acid as a hydrophilic chain extender, which is an anionic type product. It will have a relatively strong interaction force with lithium ions in lithium salts, limiting the number of lithium ion migrations. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of this application is to provide an ionic liquid-type aqueous polyurethane dispersion, which solves the problems of low conductivity and low lithium ion migration number in polymer-based electrolytes by grafting cationic ionic liquids onto the aqueous polyurethane resin body through chemical reaction.

[0007] To solve the above problems, the technical solutions adopted in this application are as follows:

[0008] The embodiment of the present application provides an ionic liquid-based waterborne polyurethane dispersion, characterized in that a cationic waterborne polyurethane dispersion is obtained by grafting a cationic liquid onto a waterborne polyurethane resin body through a chemical reaction, wherein the cationic liquid is derived from an ionic liquid alcohol.

[0009] As a further preferred solution, the ionic liquid aqueous polyurethane dispersion described in the examples of the present application has a number average molecular weight of 30,000 to 80,000 and a particle size of 20 to 80 nm.

[0010] As a further preferred solution, the ionic liquid aqueous polyurethane dispersion described in the embodiment of the present application has a solid content by mass of 20-45%, a viscosity at 25° C. of 30-200 mPa.s, and a pH value of 7-9.

[0011] As a further preferred embodiment, the ionic liquid aqueous polyurethane dispersion described in the embodiment of the present application is a cationic aqueous polyurethane dispersion obtained by chemical polymerization of monomer components having the following mass percentages:

[0012] Polycarbonate diol 8%~18%;

[0013] Isocyanate 6%~16%;

[0014] Ionic liquid alcohol 2%~10%;

[0015] Silane coupling agent 1%~5%;

[0016] Chain extender 0.01%~1.5%;

[0017] Catalyst 0.01%~0.5%;

[0018] Antioxidant 0.03%~0.3%;

[0019] Deionized water balance.

[0020] As a further preferred solution, the polycarbonate diol described in the examples of the present application has a hydroxyl value of 50-150 mgKOH / g and a number average molecular weight of 800-2000.

[0021] As a further preferred embodiment, the isocyanate described in the embodiments of the present application is one or a mixture of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate trimer, isophorone diisocyanate trimer, and hexamethylene diisocyanate trimer.

[0022] As a further preferred embodiment, the ionic liquid alcohol described in the embodiment of the present application is one or a mixture of N-methyl-N-butyldiethanolamine bromide, N,N-dibutyldiethanolamine bromide, N,N-dimethyl-N-butylethanolamine bromide, N-(N-methyl-N-butyl)-N-(N,N-dimethylaminoethyl-N-butyl)ethanolamine bromide; the ionic liquid alcohol has the chemical structural formula shown in the following (a) to (d):

[0023] .

[0024] As a further preferred embodiment, the silane coupling agent described in the embodiment of the present application is 3-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)ethyldiethoxysilane, N-(β-aminoethyl-γ-aminopropyl)trimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)triethoxysilane; the chain extender is 3,3'-dichlorobenzidine, 2,6-dichlorobenzidine, The invention relates to a catalyst comprising one or a mixture of piperazine, ethylenediamine, diethylenetriamine, 1,6-hexanediamine, isophoronediamine and trihydroxymethylpropane; the catalyst comprises one or a mixture of dibutyltin dilaurate, stannous octoate and organic bismuth; the antioxidant comprises one or a mixture of poly(dipropylene glycol)phenyl phosphite, diethylenethiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate and 2,6-di-tert-butyl-4-methylphenol.

[0025] The embodiment of the present application also provides a method for preparing an ionic liquid-type aqueous polyurethane dispersion, which adopts the reaction of polycarbonate diol, isocyanate and ionic liquid alcohol, and the steps are as follows: heating the reactant polycarbonate diol to a first preset temperature in a reactor, vacuum dehydration treatment and then cooling to a second preset temperature, adding a catalyst under the action of a protective gas, heating to a third preset temperature and reacting for 120-150 minutes, cooling to a second preset temperature, adding ionic liquid alcohol and reacting for 120-150 minutes, cooling to a fourth preset temperature, and then adding a chain extender and a silane coupling agent dissolved in a solvent dropwise to the reactor, stirring evenly after the addition is complete, heating to the second preset temperature and reacting for 60-120 minutes, adding an antioxidant and stirring evenly, cooling to a fifth preset temperature, gradually adding deionized water dropwise to the reactor for dispersion and emulsification, continuing to stir after the addition is complete, and then vacuum removing the solvent and filtering to obtain a product.

[0026] As a further preferred embodiment, the preparation method described in the embodiment of the present application further includes the step of preparing an ionic liquid alcohol: adding an amine compound to a reactor, adding an organic solvent under the action of a protective gas, stirring evenly, and then adding a brominated alkane to react. After the reaction is completed, the ionic liquid alcohol is obtained and set aside.

[0027] As a further preferred scheme, the first preset temperature described in the embodiment of the present application is 100~120℃, the second preset temperature is 50~70℃, the third preset temperature is 75~85℃, the fourth preset temperature is 35~35℃, and the fifth preset temperature is 35~45℃.

[0028] As a further preferred embodiment, in the preparation method described in the examples of the present application, the vacuum degree during vacuum dehydration and vacuum removal of solvent is above 0.092 MPa.

[0029] The embodiments of the present application also provide the use of ionic liquid aqueous polyurethane dispersions in solid electrolytes for lithium batteries.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The ionic liquid-based aqueous polyurethane dispersion described in this application is a cationic dispersion that can coordinate with anions in lithium salts, restrict anion mobility, and greatly increase the migration number of lithium ions. At the same time, due to the introduction of ionic liquid, the stability of the cationic structure is improved. Compared with conventional cationic aqueous polyurethane dispersions, it has excellent anti-yellowing properties.

[0032] 2. The ionic liquid-based aqueous polyurethane dispersion described in this application grafts the ionic liquid into the polyurethane molecular structure through a polymerization reaction; on the one hand, it can achieve excellent electrical conductivity, solve the risk of leakage after battery puncture, and reduce the crystallinity of the material through random copolymerization of multiple types of materials; on the other hand, the long side chains in the ionic liquid structure can increase the free volume of the amorphous region, further effectively providing lithium ion transmission channels.

[0033] 3. The preparation method of the ionic liquid-based aqueous polyurethane dispersion described in this application has excellent electrolyte miscibility stability and can exist stably under a wide pH range. At the same time, it has excellent film-forming properties, excellent water resistance and acid and alkali resistance, and can be used in metal surface treatment, glass fiber and other fields.

[0034] The present invention will be further described in detail below with reference to specific embodiments. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] The term "comprising" and other equivalent descriptions in the description and claims of this application are intended to cover non-exclusive inclusions, including both the contents clearly described in the description and claims and the steps or units that are not described in the description and claims but are inherent in the product, method or structure.

[0037] The embodiment of the present application provides an ionic liquid-based waterborne polyurethane dispersion, characterized in that a cationic waterborne polyurethane dispersion is obtained by grafting a cationic liquid onto a waterborne polyurethane resin body through a chemical reaction, wherein the cationic liquid is derived from an ionic liquid alcohol.

[0038] Research in this application has found that regulating the molecular weight of an ionic liquid-based aqueous polyurethane dispersion significantly improves its construction performance when used as a solid electrolyte for lithium batteries. Therefore, in a preferred embodiment of this application, the number average molecular weight of the ionic liquid-based aqueous polyurethane dispersion described in the embodiments of this application is 30,000-80,000, preferably 31,000-71,000, and further, 47,000-58,000. When the dispersed particle size of the aqueous polyurethane dispersion particles is too large, the stability of the dispersion is generally poor and particles are prone to sedimentation. When the dispersed particle size of the aqueous polyurethane dispersion particles is too small, the emulsion viscosity is high, the double layer of the particles is thicker, the charge interaction is stronger, and the aqueous polyurethane dispersion is prone to creaming. Therefore, in some embodiments of this application, the particle size of the ionic aqueous polyurethane dispersion is 20-80 nm, preferably 32-40 nm.

[0039] The solid content of the aqueous polyurethane dispersion affects its application in lithium-ion battery solid electrolytes. In order to meet the required performance of the application, the solid content of the ionic liquid aqueous polyurethane dispersion described in the examples of the present application is 20-45%, the viscosity at 25°C is 30-200 mPa.s, and the pH value is 7-9.

[0040] As a further preferred embodiment, the ionic liquid aqueous polyurethane dispersion described in the embodiment of the present application is a cationic aqueous polyurethane dispersion obtained by chemical polymerization of monomer components having the following mass percentages:

[0041] Polycarbonate diol 8%~18%;

[0042] Isocyanate 6%~16%;

[0043] Ionic liquid alcohol 2%~10%;

[0044] Silane coupling agent 1%~5%;

[0045] Chain extender 0.01%~1.5%;

[0046] Catalyst 0.01%~0.5%;

[0047] Antioxidant 0.03%~0.3%;

[0048] Deionized water balance.

[0049] Polycarbonate diol (PCDL) is a specialty polyol with excellent overall performance. Its molecular structure contains a large number of carbonate bonds, which gives the resulting polyurethane excellent mechanical properties and thermal stability. In the examples of this application, PCDL is used as the soft segment of the polyurethane. Preferably, in specific examples of this application, the hydroxyl value of the PCDL is 50-150 mgKOH / g. In some embodiments, the hydroxyl value of the PCDL is 80-150 mgKOH / g, 100-150 mgKOH / g, or 120-150 mgKOH / g. The molecular weight of the soft segment affects the glass transition temperature and dispersion properties of the polyurethane dispersion. Adjusting the molecular weight of the PCDL can improve the dispersion properties of the polyurethane dispersion. To obtain a polyurethane dispersion with a reasonable glass transition temperature and dispersion properties, the polycarbonate diol used in this application has a number average molecular weight of 800-2000. In some embodiments, the number average molecular weight of the polycarbonate diol is 1000-2000, or 1200-2000, or 1500-2000. In this application, the aqueous polyurethane dispersion is used in lithium battery solid electrolytes. To regulate the performance of the polyurethane, in some embodiments of this application, the amount of polycarbonate diol used is 8wt%-18wt%; preferably, the amount of polycarbonate diol used is 8wt%-12wt%, or 8wt%-15wt%, or 10wt%-15wt%, or 12wt%-18wt%, or 10wt%-12wt%. In a specific embodiment of the present application, the polycarbonate diol can be selected from but not limited to product models T5650, T5651, T5652, G3450, G3451, G3452 produced by Asahi KASEI, or product models UH-100, UH-200, UM-90 produced by UBE, or a mixture of two or more thereof.

[0050] In the embodiments of the present application, the isocyanate forms the hard segment phase of the polyurethane. The hard segment is an important indicator for determining the mechanical and physical properties of the polyurethane, and the selection of the hard segment phase needs to consider compatibility with the soft segment. In some embodiments of the present application, the isocyanate is one or a mixture of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate trimer, isophorone diisocyanate trimer, and hexamethylene diisocyanate trimer. Considering the impact of isocyanate and polycarbonate diol on the performance of the polyurethane dispersion, the amount of isocyanate used in this application is 6wt% to 16wt%. Preferably, in some embodiments, the amount of the isocyanate used is 8wt% to 12wt%, or 7wt% to 13wt%, or 10wt% to 15wt%, or 8wt% to 15wt%.

[0051] The ionic liquid alcohol in the embodiments of the present application refers to an ionic liquid with an alcoholic hydroxyl group, preferably an ionic liquid alcohol with a long side chain, and can be a monohydric alcohol, a dihydric alcohol, or a polyhydric alcohol. Preferably, in some embodiments, the ionic liquid alcohol is N-methyl-N-butyldiethanolamine bromide, N,N-dibutyldiethanolamine bromide, N,N-dimethyl-N-butylethanolamine bromide; N-(N-methyl-N-butyl)-N-(N,N-dimethylaminoethyl-N-butyl)ethanolamine bromide, or a mixture thereof; the ionic liquid alcohol has the chemical structural formula shown in the following (a) to (d):

[0052] .

[0053] In some embodiments of the present application, an ionic liquid alcohol with the above-described structure is introduced into the main structure of a waterborne polyurethane resin. On the one hand, the resulting polyurethane dispersion is positively charged, forming a cationic polyurethane dispersion. When used as a solid electrolyte for lithium batteries, it can coordinate with anions in lithium salts, restricting anion flow, thereby greatly increasing the transference number of lithium ions. On the other hand, the incorporation of the ionic liquid gives the polyurethane dispersion a stable cationic structure, which is more resistant to yellowing than conventional cationic waterborne polyurethane dispersions. Furthermore, the ionic liquid alcohol used in the embodiments of the present application is an ionic liquid alcohol with long side chains. Long side chains can increase the free volume of the amorphous region and effectively provide lithium ion transport channels. In the embodiments of the present application, the amount of the ionic liquid alcohol used is 2 wt% to 10 wt%. Preferably, in some embodiments, the amount of the ionic liquid alcohol used is 3 wt% to 8 wt%, or 2 wt% to 5 wt%, or 5 wt% to 8 wt%, or 5 wt% to 10 wt%.

[0054] Furthermore, in some embodiments, the ionic liquid alcohol is prepared using the following method: an alcoholamine compound is added to a reactor, an organic solvent is added under a protective gas atmosphere, and the mixture is stirred until uniform. A brominated alkane is then added for reaction. After the reaction is complete, the ionic liquid alcohol is obtained and set aside. During the preparation of the ionic liquid alcohol, the protective gas is nitrogen or an inert gas at 55-65°C, and the molar ratio of the alcoholamine to bromobutyl is (1.01-1.05):1. The bromobutyl is added dropwise at a rate of 1.5-2.5 g / min. Preferably, the rate is 2.0 g / min.

[0055] The silane coupling agent described in the embodiments of the present application is one or a mixture of 3-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)ethyldiethoxysilane, N-(β-aminoethyl-γ-aminopropyl)trimethoxysilane, and N-(β-aminoethyl-γ-aminopropyl)triethoxysilane. Preferably, the silane coupling agent is used in an amount of 2 wt% to 5 wt%. In the reaction system of the polyurethane dispersion, the silane coupling agent provides an organosilicon component that has a flame retardant effect after the reaction. In this way, a flame-retardant functional monomer is incorporated into the polyurethane body, achieving flame retardant properties and meeting safety requirements during lithium battery applications.

[0056] The reaction system of the present application also includes a chain extender. In the present application, considering that amine chain extenders have high cohesive energy, fast reaction speed, and low required reaction temperature, in some embodiments of the present application, amine chain extenders are mainly used. Specifically, the chain extender is one or more mixtures of 3,3'-dichlorobenzidine, 2,6-dichloropiperazine, ethylenediamine, diethylenetriamine, 1,6-hexanediamine, isophoronediamine, and trimethylolpropane. In the embodiments of the present application, in order to avoid the fast reaction speed of the amine chain extender, which causes the relative molecular weight of the product to increase sharply, resulting in an uncontrolled reaction, it is necessary to control the amount of chain extender added. In some embodiments of the present application, the amount of chain extender is 0.01wt%~1.5wt%; preferably, in some embodiments, the amount of the chain extender is 0.5wt%~1.0wt%, or 0.05wt%~0.5wt%, or 0.1wt%~1.0wt%, or 0.01wt%~1.5wt%.

[0057] The reaction system of the present application also includes a catalyst. In some embodiments, the catalyst is one or a mixture of dibutyltin dilaurate, stannous octoate, and organic bismuth; the antioxidant is one or a mixture of poly(dipropylene glycol) phenyl phosphite, diethylenethiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,5-di-tert-butyl-4-hydroxyphenylpropionate, and 2,6-di-tert-butyl-4-methylphenol.

[0058] The embodiment of the present application also provides a method for preparing an ionic liquid-type aqueous polyurethane dispersion, which adopts the reaction of polycarbonate diol, isocyanate and ionic liquid alcohol, and the steps are as follows: heating the reactant polycarbonate diol to a first preset temperature in a reactor, vacuum dehydration treatment and then cooling to a second preset temperature, adding a catalyst under the action of a protective gas, heating to a third preset temperature and reacting for 120-150 minutes, cooling to a second preset temperature, adding ionic liquid alcohol and reacting for 120-150 minutes, cooling to a fourth preset temperature, and then adding a chain extender and a silane coupling agent dissolved in a solvent dropwise to the reactor, stirring evenly after the addition is complete, heating to the second preset temperature and reacting for 60-120 minutes, adding an antioxidant and stirring evenly, cooling to a fifth preset temperature, gradually adding deionized water dropwise to the reactor for dispersion and emulsification, continuing to stir after the addition is complete, and then vacuum removing the solvent and filtering to obtain a product.

[0059] As a further preferred scheme, the first preset temperature described in the embodiment of the present application is 100~120℃, the second preset temperature is 50~70℃, the third preset temperature is 75~85℃, the fourth preset temperature is 35~35℃, and the fifth preset temperature is 35~45℃.

[0060] As a further preferred embodiment, in the preparation method described in the examples of the present application, the vacuum degree during vacuum dehydration and vacuum removal of solvent is above 0.092 MPa.

[0061] The embodiments of the present application also provide the use of ionic liquid aqueous polyurethane dispersions in solid electrolytes for lithium batteries.

[0062] Example 1

[0063] This embodiment provides an ionic liquid-based aqueous polyurethane dispersion, which is prepared by the following method:

[0064] Preparation of ionic liquid alcohol: 90 g of N-methyldiethanolamine was placed in a reactor under nitrogen protection. 30 g of ethyl acetate solvent was added and stirred evenly at 60°C for 15 min. 102.4 g of bromobutane was gradually added dropwise to the reactor at a dropwise addition rate of about 2 g / min. After the addition was complete, the reaction was carried out at 60°C for 60 min. After the reaction was completed, the target product was obtained by discharging the material.

[0065] Preparation of waterborne polyurethane dispersion: 60g of polycarbonate diol (model UM-90) produced by UBE was added to the reactor according to the ratio, the temperature was raised to 110°C, vacuum dehydrated at 0.092MPa for 90min, cooled to 60°C, protected by nitrogen, 64g of isophorone diisocyanate and 100g of butanone (to dissolve and disperse the polycarbonate diol) were added, stirred evenly for 15min, 0.1g of dibutyltin dilaurate was added, reacted at 80°C for 120min, cooled to 60°C, 38.7g of ionic liquid alcohol a, i.e. N-methyl-N-butyldiethanolamine bromide, reacted for 150min, cooled to 30°C, 4g of 2,6-dichloropiperazine and 6g of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane was dissolved or dispersed in 20g of butanone and gradually added dropwise to the reactor. After the addition was completed, the temperature was gradually raised to 60°C after uniform stirring for 15 minutes, and the reaction was carried out for 60 minutes. 0.5g of antioxidant poly(dipropylene glycol) phenyl phosphite was added and stirred for 15 minutes. The temperature was lowered to 40°C, and 510g of deionized water was gradually added dropwise to the reactor for high-speed dispersion and emulsification. The addition time was 60 minutes. After the addition was completed, stirring was continued for 30 minutes. The butanone was removed by vacuum at 50°C, and the vacuum degree was maintained above 0.092MPa. After the solvent was removed, the material was filtered and discharged. Some deionized water was appropriately added in the intermediate process to obtain an aqueous polyurethane dispersion with a solid content of 25%.

[0066] Example 2

[0067] This embodiment provides an ionic liquid-based aqueous polyurethane dispersion, which is prepared by the following method:

[0068] Preparation of ionic liquid alcohol: 110 g of N-butyldiethanolamine was placed in a reactor under nitrogen protection. 30 g of ethyl acetate solvent was added and stirred evenly at 60°C for 15 min. 92.5 g of bromobutane was gradually added dropwise to the reactor at a dropwise addition rate of about 2 g / min. After the addition was complete, the reaction was carried out at 60°C for 60 min. After the reaction was completed, the target product was obtained by discharging the material.

[0069] Preparation of waterborne polyurethane dispersion: 60g of T5651 polycarbonate diol produced by AsahiKASEI Company was added to the reactor according to the ratio, the temperature was raised to 110°C, vacuum dehydrated at 0.092MPa for 90min, cooled to 60°C, protected by nitrogen, 66g of 4,4'-dicyclohexylmethane diisocyanate and 100g of butanone (to dissolve and disperse polycarbonate diol) were added, stirred evenly for 15min, 0.2g of organic bismuth was added, reacted at 80°C for 120min, cooled to 60°C, and a mixture of 19.3g of ionic liquid alcohol a and 18.5g of ionic liquid alcohol b, i.e., N-methyl-N-butyldiethanolamine bromide and N,N-dibutyldiethanolamine bromide, was added, reacted for 150min, cooled to 30°C, and 4g of 3,3'-dichlorobenzidine, 4g of isophoronediamine, and 3g of 3-Aminopropyltriethoxysilane and 5g N-(β-aminoethyl)-γ-aminopropyltriethoxysilane were dissolved or dispersed in 30g butanone and gradually added dropwise to the reactor. After the addition was completed, the temperature was gradually raised to 60°C and reacted for 60 minutes. 0.5g of antioxidant 3,5-di-tert-butyl-4-hydroxyphenylpropionate was added and stirred for 15 minutes. The temperature was lowered to 40°C and 410g of deionized water was gradually added dropwise to the reactor for high-speed dispersion and emulsification. The addition time was 60 minutes. After the addition was completed, the stirring was continued for 30 minutes. The butanone was removed by vacuum at 50°C, and the vacuum degree was maintained above 0.092MPa. After the solvent was removed, the material was filtered and discharged. Some deionized water was appropriately added in the intermediate process to obtain a water-based polyurethane dispersion with a solid content of 30%.

[0070] Example 3

[0071] This embodiment provides an ionic liquid-based aqueous polyurethane dispersion, which is prepared by the following method:

[0072] Preparation of ionic liquid alcohol: 80 g of N,N-dimethylethanolamine was placed in a reactor under nitrogen protection. 30 g of ethyl acetate solvent was added and stirred evenly at 60°C for 15 min. 121.7 g of bromobutane was gradually added dropwise into the reactor at a dropwise addition rate of about 2 g / min. After the addition was complete, the reaction was carried out at 60°C for 60 min. After the reaction was completed, the target product was obtained by discharging the material.

[0073] Preparation of waterborne polyurethane dispersion: 70g of UBE product model UH-200 polycarbonate diol was added to the reactor according to the ratio, the temperature was raised to 110°C, vacuum dehydrated at 0.092MPa for 120min, cooled to 60°C, protected by nitrogen, 66g of 4,4'-dicyclohexylmethane diisocyanate and 100g of butanone (to dissolve and disperse the polycarbonate diol) were added, stirred evenly for 15min, 0.15g of stannous octoate was added, reacted at 80°C for 120min, cooled to 60°C, 25.8g of ionic liquid alcohol a and 15.2g of ionic liquid alcohol c, i.e., N-methyl-N-butyldiethanolamine bromide and N,N-dimethyl-N-butylethanolamine bromide, were added, reacted for 150min, cooled to 30°C, 8g of 3,3'-dichlorobenzidine and 5g of γ-Aminopropylmethyldiethoxysilane was dissolved or dispersed in 30g of butanone and gradually added dropwise to the reactor. After the addition was completed, the temperature was gradually raised to 60°C after uniform stirring for 15 minutes, and the reaction was carried out for 60 minutes. 0.5g of antioxidant 2,6-di-tert-butyl-4-methylphenol was added and stirred for 15 minutes. The temperature was lowered to 40°C, and 360g of deionized water was gradually added dropwise to the reactor for high-speed dispersion and emulsification. The addition time was 60 minutes. After the addition was completed, the stirring was continued for 30 minutes. The butanone was removed by vacuum at 50°C, and the vacuum degree was maintained above 0.092MPa. After the solvent was removed, the material was filtered and discharged. Some deionized water was appropriately added in the intermediate process to obtain an aqueous polyurethane dispersion with a solid content of 35%.

[0074] Example 4

[0075] This embodiment provides an ionic liquid-based aqueous polyurethane dispersion, which is prepared by the following method:

[0076] Preparation of ionic liquid alcohol: 100 g of N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine was placed in a reactor under nitrogen protection. 30 g of ethyl acetate solvent was added and stirred evenly at 60°C for 15 min. 92.7 g of bromobutane was gradually added dropwise into the reactor at a dropwise addition rate of about 2 g / min. After the addition was complete, the reaction was carried out at 60°C for 60 min. After the reaction was completed, the target product was obtained by discharging the material.

[0077] Preparation of waterborne polyurethane dispersion: 40g of polycarbonate diol G3450 produced by AsahiKASEI and 20g of polycarbonate diol UH-200 produced by UBE were added to the reactor according to the ratio, the temperature was raised to 110°C, vacuum dehydrated at 0.092MPa for 120min, cooled to 60°C, nitrogen was used for protection, and 37g of 4,4'-dicyclohexylmethane diisocyanate, 28g isophorone diisocyanate and 100g butanone (to dissolve and disperse polycarbonate diol) were stirred evenly for 15 minutes, 0.12g dibutyltin dilaurate was added, and the mixture was reacted at 80℃ for 120 minutes. The temperature was lowered to 60℃, and a mixture of 25.8g ionic liquid alcohol a and 19.3g ionic liquid alcohol d, namely N-methyl-N-butyldiethanolamine bromide and N-(N-methyl-N-butyl)-N-(N,N-dimethylaminoethyl-N-butyl)ethanolamine bromide, was added and the mixture was reacted for 150 minutes. The temperature was lowered to 30℃, and 3g 2,6-dichloropiperazine, 2.5g ethylenediamine, 3g γ-aminopropylmethyldiethoxysilane and 4g N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane was dissolved or dispersed in 30g of butanone and gradually added dropwise to the reactor. After the addition was completed, the temperature was gradually raised to 60°C after uniform stirring for 15 minutes, and the reaction was carried out for 60 minutes. 0.5g of antioxidant 2,6-di-tert-butyl-4-methylphenol was added and stirred for 15 minutes. The temperature was lowered to 40°C, and 320g of deionized water was gradually added dropwise to the reactor for high-speed dispersion and emulsification. The addition time was 60 minutes. After the addition was completed, the stirring was continued for 30 minutes. The butanone was removed by vacuum at 50°C, and the vacuum degree was maintained above 0.092MPa. After the solvent was removed, the material was filtered and discharged. Some deionized water was appropriately added in the intermediate process to obtain an aqueous polyurethane dispersion with a solid content of 32%.

[0078] Example 5

[0079] This embodiment provides an ionic liquid-based aqueous polyurethane dispersion, which is prepared by the following method:

[0080] Preparation of waterborne polyurethane dispersion: 30g of polycarbonate diol (UM-90) produced by UBE and 40g of polycarbonate diol (UH-100) produced by UBE were added to the reactor according to the ratio, the temperature was raised to 110°C, vacuum dehydrated at 0.092MPa for 120min, cooled to 60°C, protected by nitrogen, 14g of hexamethylene diisocyanate, 37g of isophorone diisocyanate and 100g of butanone (to dissolve and disperse the polycarbonate diol) were added, stirred evenly for 15min, 0.1g of dibutyltin dilaurate was added, the reaction was carried out at 80°C for 120min, cooled to 60°C, 37.0g of ionic liquid alcohol b, i.e. N,N-dibutyldiethanolamine bromide, reacted for 150min, cooled to 30°C, 1.5g of 2,6-dichloropiperazine and 4g of 3,3'-Dichlorobenzidine and 8g N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane were dissolved or dispersed in 30g butanone and gradually added dropwise to the reactor. After the addition was completed, the temperature was gradually raised to 60°C and reacted for 60 minutes. 0.5g of antioxidant poly(dipropylene glycol) phenyl phosphite was added and stirred for 15 minutes. The temperature was lowered to 40°C and 290g of deionized water was gradually added dropwise to the reactor for high-speed dispersion and emulsification. The addition time was 60 minutes. After the addition was completed, the stirring was continued for 30 minutes. The butanone was removed by vacuum at 50°C, and the vacuum degree was maintained above 0.092MPa. After the solvent was removed, the material was filtered and discharged. Some deionized water was appropriately added during the process to obtain an aqueous polyurethane dispersion with a solid content of 37%.

[0081] Comparative Example 1

[0082] Preparation of waterborne polyurethane dispersion: add 65g of polytetramethylene ether glycol (molecular weight 1000) to the reactor according to the ratio, heat to 110℃, dehydrate under vacuum at 0.092MPa for 120min, cool to 60℃, protect with nitrogen, add 55g of 4,4'-dicyclohexylmethane diisocyanate and 100g of butanone (solubilizer for dispersing macromolecular diol), stir evenly for 15min, add 0.1g of dibutyltin dilaurate, react at 80℃ for 120min, cool to 60℃, add 12g of N-methyldiethanolamine, react for 60min, and gradually add 3.5g of 1,4-Butanediol was added dropwise to the reactor and reacted at 60°C for 120 minutes. 0.5g of antioxidant poly(dipropylene glycol) phenyl phosphite was added and stirred for 15 minutes. The temperature was lowered to 40°C, and 6g of acetic acid was added dropwise for neutralization. After the addition was completed, stirring was continued for 30 minutes. 330g of deionized water was gradually added dropwise to the reactor for high-speed dispersion and emulsification. After the addition was completed, stirring was continued for 30 minutes. Butanone was removed by vacuum at 50°C, and the vacuum degree was maintained above 0.092MPa. After the solvent was removed, the material was filtered and discharged. Some deionized water was appropriately added in the intermediate process to obtain an aqueous polyurethane dispersion with a solid content of 30%.

[0083] Comparative Example 2

[0084] Preparation of waterborne polyurethane dispersion: Add 70g of polycaprolactone diol (molecular weight 2000) to the reactor according to the ratio, heat to 110℃, dehydrate under 0.092MPa vacuum for 120min, cool to 60℃, protect with nitrogen, add 46g of isophorone diisocyanate and 100g of butanone (to dissolve and disperse the macromolecular diol), stir evenly for 15min, add 0.1g of dibutyltin dilaurate, react at 80℃ for 120min, cool to 60℃, add 9g of N-methyldiethanolamine and 4g of N, N-dimethylethanolamine, react for 60 minutes, gradually add 4.0g of ethylenediamine dropwise to the reactor, react at 60°C for 120 minutes, add 0.5g of antioxidant 2,6-di-tert-butyl-4-methylphenol, stir for 15 minutes, cool to 40°C, add 7.2g of acetic acid dropwise for neutralization, stir for 30 minutes after the addition is complete, gradually add 260g of deionized water dropwise to the reactor for high-speed dispersion and emulsification, continue stirring for 30 minutes after the addition is complete, vacuum remove butanone at 50°C, and maintain the vacuum degree above 0.092MPa. After the solvent is removed, filter and discharge the material. Some deionized water is appropriately added in the intermediate process to obtain a water-based polyurethane dispersion with a solid content of 35%.

[0085] The waterborne polyurethane dispersions prepared by the methods of Examples 1-5 and Comparative Examples 1-2 were tested for performance in accordance with international standards or commonly used industry methods. The emulsion solids content was tested according to GB / T 1725-2007. 3.00 g of the emulsion was placed in an aluminum foil tray approximately 5 cm in diameter. The tray was then placed in a forced-air oven at 105°C for several hours until the weight change between the two measurements was less than 0.01 g. The emulsion solids content was then calculated. Emulsion viscosity was tested according to GB / T 21059-2007. pH was tested according to GB / T 8325-1987. Emulsion particle size was tested according to GB / T 29022-2021. Number-average molecular weight was determined using a TOSOH HLC-8420GPC high-performance gel permeation chromatograph with tetrahydrofuran as the mobile phase. See Table 1 for test results.

[0086] Table 1: Components and properties of waterborne polyurethane dispersions

[0087] Item Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Solid content (wt%) 25303532373035 Viscosity MPa.s 2321283140120150 pH value 7.88.18.38.57.95.85.5 Number average molecular weight 33000310004700058000710002100028000 Particle size, D 50 ,nm3230373540113135

[0088] Application Examples 1-7

[0089] The aqueous polyurethane dispersions prepared according to the methods of Examples 1-5 and Comparative Examples 1-2 were respectively applied in the field of lithium battery solid electrolytes. Application Examples 1-5 used the aqueous polyurethane dispersions of Examples 1-5 to prepare lithium battery solid electrolytes, while Application Examples 6-7 used the polyurethane dispersions described in Comparative Examples 1-2 to prepare lithium battery solid electrolytes. The specific application methods are as follows.

[0090] The solid electrolyte for lithium batteries was prepared as follows: an aqueous polyurethane dispersion and lithium bis(trifluoromethanesulfonyl)imide were mixed in proportion, a small amount of dibutyl phthalate (DPPH) plasticizer was added, and mechanical stirring was followed by passing the mixture through a high-pressure homogenizer at 1500 bar to obtain a solution precursor. An appropriate amount of the precursor solution was weighed and cast onto a polytetrafluoroethylene template. The mixture was dried at room temperature for 48 hours and then vacuum-dried at 60°C for 24 hours to obtain an electrolyte film with a thickness of 250-300 μm. The aqueous polyurethane accounted for 65% of the electrolyte polymer by mass, and the lithium bis(trifluoromethanesulfonyl)imide accounted for 35% of the electrolyte polymer by mass.

[0091] Film Preparation: The electrolyte solution precursor was gently poured into a horizontally placed polytetrafluoroethylene mold, dried at room temperature for 48 hours, and then vacuum-dried at 60°C for 24 hours to form a film. Tensile Strength Testing: The tensile properties of the film were tested using an electronic universal testing machine according to GB / T528-2009 at a rate of 50 mm / min.

[0092] The ionic conductivity of the electrolyte was measured using electrochemical impedance spectroscopy (EIS) using a Princeton Applied Research PARSTAT 4000A electrochemical workstation. A button cell was assembled in the order of the positive electrode shell, solid electrolyte, copper sheet, and negative electrode shell. The EIS test frequency range was 0.1 Hz to 100 kHz, with an amplitude of 5 mV. Before testing, the battery was allowed to rest for approximately 1 hour at each temperature. Three measurements were taken at each temperature, and the average was taken to determine the bulk impedance of the electrolyte at that temperature. The ionic conductivity σ of the electrolyte was calculated as follows:

[0093] σ=L / (R b *S)

[0094] Among them, R b , L and S are the bulk impedance (Ω), thickness (cm) and effective area (cm) of the electrolyte, respectively. 2 The ionic conductivity of the ionic liquid and lithium salt-ionic liquid solution was measured using a DDS-11A digital conductivity meter. A constant temperature water bath was used for temperature control with an accuracy of ±0.1°C.

[0095] Measurements were performed using a Princeton Applied Research PARSTAT 4000A electrochemical workstation using chronoamperometry and AC impedance spectroscopy at 25°C. A button cell was assembled in the order of the positive electrode shell, solid electrolyte, copper sheet, and negative electrode shell. When using the chronoamperometry method for measurement, a polarization voltage (ΔV) of 10 mV was applied across the battery, and the initial current value I0 and the current value Is after reaching steady state were recorded. AC impedance measurements were performed on the battery before and after polarization to obtain the initial interfacial impedance R0 and the interfacial impedance Rs after reaching steady state. The lithium ion transference number of the electrolyte was calculated using the following formula:

[0096] t Li+ =I S / I0*(ΔV-I0R0) / (ΔV-I S R S ))

[0097] See Table 2 for the results.

[0098] Table 2: Film and coating properties

[0099] Components Application Example 1 Application Example 2 Application Example 3 Application Example 4 Application Example 5 Application Example 1 Application Example 2 Young's modulus MPa 250 280 230 290 380 90 30 Ionic conductivity, S cm -1 , 25℃6.1×10 -4 5.5×10 -4 7.3×10 -4 8.2×10 -4 4.7×10 -4 1.2×10 -5 3.6×10 -5 Lithium ion migration number 0.750.730.880.810.630.190.31

[0100] It can be seen from Tables 1 and 2 that, compared with the polyurethane dispersions obtained by Comparative Examples 1 and 2, the solid electrolyte prepared by using the aqueous polyurethane dispersion described in the examples of the present application has excellent ionic conductivity and lithium ion transference number, as well as excellent Young's modulus.

[0101] The above-mentioned implementation mode provided in the embodiment of the present application is only a preferred implementation mode of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and replacements made by technical personnel in this field on the basis of the present invention shall fall within the scope of protection requested by the present invention.

Claims

1. An ionic liquid type aqueous polyurethane dispersion, characterized in that: The cationic waterborne polyurethane dispersion is obtained by grafting a cationic ionic liquid onto a waterborne polyurethane resin body through a chemical reaction, wherein the cationic liquid is derived from an ionic liquid alcohol; and the liquid ionic alcohol is an ionic liquid alcohol with a long side chain.

2. The ionic liquid type aqueous polyurethane dispersion according to claim 1, characterized in that: Its number average molecular weight is 30,000~80,000 and its particle size is 20~80nm.

3. The ionic liquid type aqueous polyurethane dispersion according to claim 1, characterized in that: The solid content is 20~45%, the viscosity at 25°C is 30~200MPa.s, and the pH value is 7~9.

4. The ionic liquid type aqueous polyurethane dispersion according to any one of claims 1 to 3, characterized in that: It is a cationic waterborne polyurethane dispersion obtained by chemical polymerization of the following monomer components by mass percentage: Polycarbonate diol 8%~18%; Isocyanate 6%~16%; Ionic liquid alcohol 2%~10%; Silane coupling agent 1%~5%; Chain extender 0.01%~1.5%; Catalyst 0.01%~0.5%; Antioxidant 0.03%~0.3%; Deionized water balance.

5. The ionic liquid type aqueous polyurethane dispersion according to claim 4, characterized in that: The polycarbonate diol has a hydroxyl value of 50-150 mgKOH / g and a number average molecular weight of 800-2000.

6. The ionic liquid type aqueous polyurethane dispersion according to claim 4, characterized in that: The isocyanate is one or a mixture of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate trimer, isophorone diisocyanate trimer and hexamethylene diisocyanate trimer.

7. The ionic liquid type aqueous polyurethane dispersion according to claim 4, characterized in that: The ionic liquid alcohol is one or a mixture of N-methyl-N-butyldiethanolamine bromide, N,N-dibutyldiethanolamine bromide, N,N-dimethyl-N-butylethanolamine bromide, N-(N-methyl-N-butyl)-N-(N,N-dimethylaminoethyl-N-butyl)ethanolamine bromide; the ionic liquid alcohol has the chemical structural formulas shown in (a) to (d) below: 。 8. The ionic liquid type aqueous polyurethane dispersion according to claim 4, characterized in that: The silane coupling agent is one or a mixture of 3-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)ethyldiethoxysilane, N-(β-aminoethyl-γ-aminopropyl)trimethoxysilane, and N-(β-aminoethyl-γ-aminopropyl)triethoxysilane; the chain extender is 3,3'-dichlorobenzidine, 2,6-dichloropiperazine, ethylenediamine, diethyl The invention discloses a novel catalyst for preparing the present invention, wherein the catalyst is one or a mixture of dibutyltin dilaurate, stannous octoate and organic bismuth; the catalyst is one or a mixture of poly(dipropylene glycol) phenyl phosphite, diethylene thiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate and 2,6-di-tert-butyl-4-methylphenol.

9. A method for preparing the ionic liquid aqueous polyurethane dispersion according to any one of claims 1 to 8, characterized in that: The method adopts polycarbonate diol, isocyanate and ionic liquid alcohol to react, and the steps are as follows: the reactant polycarbonate diol is heated to a first preset temperature in a reactor, and the temperature is lowered to a second preset temperature after vacuum dehydration treatment, a catalyst is added under the action of a protective gas, the temperature is raised to a third preset temperature and reacted for 120 to 150 minutes, the temperature is lowered to a second preset temperature, the ionic liquid alcohol is added and reacted for 120 to 150 minutes, the temperature is lowered to a fourth preset temperature, and then a chain extender and a silane coupling agent dissolved in a solvent are added dropwise to the reactor, and after the dropwise addition is completed, the temperature is raised to the second preset temperature and reacted for 60 to 120 minutes, an antioxidant is added and stirred evenly, the temperature is lowered to a fifth preset temperature, and deionized water is gradually added dropwise to the reactor for dispersion and emulsification, and after the dropwise addition is completed, the stirring is continued, and then the solvent is removed in vacuum and filtered to obtain a product.

10. The preparation method according to claim 9, characterized in that: The invention also includes the steps of preparing ionic liquid alcohol: adding an alcohol amine compound into a reaction kettle, adding an organic solvent under the action of a protective gas, stirring evenly and then adding a brominated alkane for reaction, and obtaining the ionic liquid alcohol after the reaction is completed for standby use.

11. The preparation method according to claim 10, characterized in that The first preset temperature is 100-120°C, the second preset temperature is 50-70°C, the third preset temperature is 75-85°C, the fourth preset temperature is 35-35°C, and the fifth preset temperature is 35-45°C.

12. The preparation method according to claim 10, characterized in that During the vacuum dehydration and vacuum solvent removal process, the vacuum degree is above 0.092 MPa.

13. Use of the ionic liquid aqueous polyurethane dispersion according to any one of claims 1 to 8 in a solid electrolyte for lithium batteries.

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