Fluorosilicone waterborne polyurethane and preparation method thereof

Abstract

The invention discloses fluorosilicone waterborne polyurethane and a preparation method thereof, and the fluorosilicone waterborne polyurethane is prepared from the following raw materials in parts by weight: 180 to 230 parts of hydroxyl-terminated compound, 30 to 40 parts of polyisocyanate, 6 to 10 parts of siloxane chain extender, 0.4 to 0.7 part of catalyst, 15 to 20 parts of hydrophilic monomer, 10 to 15 parts of triethylamine and 400 to 550 parts of deionized water. According to the fluorine-silicon waterborne polyurethane, the fluorine-containing siloxane chain extender with a specific structure is designed and adopted, so that the reaction activity in the preparation process of a prepolymer and the structure of a final polymer are effectively regulated and controlled, and a waterborne polyurethane dispersion which is moderate in viscosity and stable in storage and can improve the performance through subsequent crosslinking is successfully prepared; according to the method, the problems that high-crosslinking-degree waterborne polyurethane is difficult to prepare by a traditional prepolymer method and gelation and hydrolysis are easily caused by direct application of amino siloxane are solved, and a new technical approach is provided for preparation of the high-performance waterborne polyurethane.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterborne polyurethane, and in particular relates to a fluorosilicone waterborne polyurethane and a preparation method thereof. Background Art

[0002] Solvent-based polyurethane (PU) is widely used in applications such as wood surface protection, adhesives, and artificial leather due to its excellent performance. However, the production, application, and curing processes of PU require the addition of large amounts of volatile organic solvents, which pose health and safety risks and environmental pollution. Unlike solvent-based PU, water-based PU uses water as its medium. Water is non-flammable, non-explosive, non-toxic, and odorless, thus preventing environmental pollution. Furthermore, it offers favorable application conditions, is safe to produce and apply, and poses no health risks to construction personnel or operators. Furthermore, water is inexpensive and readily available, significantly reducing product costs. Consequently, it has attracted increasing attention and is a viable alternative to solvent-based PU.

[0003] As an environmentally friendly polymer material, waterborne polyurethane has become a research hotspot in the fields of coatings, adhesives, and leather treatment agents due to its advantages such as the absence of organic solvents or extremely low organic solvent content, adjustable film-forming properties, and wide application. Its preparation methods are diverse, of which the acetone method and prepolymer dispersion method are the more commonly used technical routes in industry. However, the traditional acetone method requires the use of large amounts of acetone as a solvent, which consumes a lot of energy during the synthesis and desolventization and recovery processes. At the same time, acetone has a low boiling point and is easily volatile, making it difficult to achieve a recovery rate of more than 99%, resulting in large carbon emissions and energy waste. While the prepolymer dispersion method avoids the use of large amounts of organic solvents, it faces difficulties such as high prepolymer viscosity and difficulty in emulsification, making it difficult to promote on a large scale. In addition, the waterborne polyurethane resin prepared has a low molecular weight, basically no cross-linking structure, and a narrow range of applications.

[0004] In order to solve the above problems, the commonly used solutions are mainly to reduce the viscosity of the prepolymer by using special isocyanates, special polyols, a small amount of high-boiling point solvents, or dilution with acrylic active monomers, and then synthesize polyurethane dispersions. However, due to the viscosity limitation of the prepolymer, it is impossible to synthesize products with high cross-linking degree, high strength and excellent performance. In addition, high-power emulsification equipment is required for production emulsification, which is difficult to operate and has poor product stability. At the same time, based on environmental protection and performance requirements, the use of the prepolymer method to prepare water-based polyurethane dispersions with high cross-linking degree is an inevitable trend and also a difficulty in the industry.

[0005] Cross-linking waterborne polyurethanes can improve their mechanical strength and hydrolysis resistance. Conventional approaches involve adding multifunctional small-molecule monomers or macromolecular triols to enhance cross-linking. For example, adding aminosilicone to the prepolymer is a common method for increasing cross-linking. However, aminosilicone is highly reactive and prone to gelation. Furthermore, siloxanes are susceptible to hydrolysis, rendering them ineffective. Chinese patent application CN101974221A discloses a method for synthesizing a water-based polyurethane emulsion for reinforcing non-woven fabrics. The method involves adding a polyether polyol, a small molecule diol, and toluene diisocyanate to a reaction vessel and reacting them at 75-80°C for one hour to obtain a prepolymer. Trimethylolpropane and dimethylolpropionic acid are then added, along with a cosolvent (N,N-dimethylacetamide) and a catalyst (dibutyltin dilaurate), and the mixture is reacted at 70°C for two hours. The mixture is cooled to 50°C, and triethylamine is added for neutralization. After neutralization, the mixture is emulsified and dispersed in deionized water. A diamine chain extender is then added dropwise for chain extension. The mixture is then defoamed and filtered to obtain a water-based polyurethane emulsion. This invention improves the strength, wear resistance, and water resistance of water-based polyurethanes by reducing the amount of hydrophilic groups, increasing the content of hard segments and benzene rings in the water-based polyurethane structure, and performing partial internal crosslinking. However, the polyurethanes obtained using this method, which uses multifunctional small molecule monomers or large molecule triols, have a low degree of crosslinking, limiting the potential for improving the performance of polyurethane products. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a fluorosilicone waterborne polyurethane and a preparation method thereof.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A fluorosilicone waterborne polyurethane comprising the following raw materials in parts by weight:

[0009] 180-230 parts of terminal hydroxyl compound, 30-40 parts of polyisocyanate, 6-10 parts of siloxane chain extender, 0.4-0.7 parts of catalyst, 15-20 parts of hydrophilic monomer, 10-15 parts of triethylamine, and 400-550 parts of deionized water.

[0010] Preferably, the terminal hydroxyl compound is one or more of terminal hydroxyl polyacrylate, terminal hydroxyl polyester, and terminal hydroxyl polyether; the polyisocyanate is one or more of diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hexamethylene diisocyanate trimer, tetramethyl-m-xylylene diisocyanate, and methylcyclohexane diisocyanate.

[0011] Preferably, the catalyst is one or more of dibutyltin dilaurate, stannous isooctanoate, zinc isooctanoate, and bismuth isooctanoate.

[0012] Preferably, the hydrophilic monomer is one or both of dihydroxypropionic acid and dihydroxybutyric acid.

[0013] Preferably, the structural formula of the siloxane chain extender is as follows:

[0014]

[0015] Preferably, the preparation method of the siloxane chain extender comprises the following steps:

[0016] S1, adding hexafluoropropylene oxide dimer to diethyl ether, then adding glycidol, stirring and reacting, and removing the solvent by reduced pressure distillation after the reaction is completed to obtain hexafluoropropylene oxide dimer epoxy ester;

[0017] S2. Hexafluoropropylene oxide dimer epoxy ester and aminopropyl trimethoxysiloxane were added to a three-necked flask, nitrogen was introduced, and a constant temperature reaction was carried out to obtain a siloxane chain extender.

[0018] Preferably, in step S1, the molar ratio of hexafluoropropylene oxide dimer to glycidol is 1:1, the stirring reaction temperature is 25-30° C., and the time is 10-15 hours.

[0019] In the present invention, the reaction process in step S1 is as follows:

[0020]

[0021] Preferably, in step S2, the molar ratio of hexafluoropropylene oxide dimer epoxy ester to aminopropyl trimethoxysiloxane is 1:1, and the stirring reaction temperature is 20-25° C. and the time is 3-5 hours.

[0022] In the present invention, the reaction process in step S2 is as follows:

[0023]

[0024] The present invention also provides a method for preparing a fluorosilicone waterborne polyurethane, comprising the following steps:

[0025] (1) Add a terminal hydroxyl compound and a hydrophilic monomer to a three-necked flask, dehydrate under vacuum conditions for 1-2 hours, cool to below 40°C, then add a polyisocyanate and a catalyst, and stir to obtain a mixture;

[0026] (2) nitrogen is introduced into the mixture in step (1) under stirring conditions, and then the temperature is raised to 60-100° C. and kept warm for 1-3 hours. After the NCO content of the test system has been reduced to the theoretical value, a siloxane chain extender is added and the temperature is continued to be kept warm until the NCO content is completely reacted to obtain a polyurethane prepolymer;

[0027] (3) adding triethylamine to the polyurethane prepolymer in step (2) to carry out a neutralization reaction, and slowly adding deionized water under high-speed stirring after the reaction is completed to form a stable emulsion.

[0028] Preferably, the temperature of the vacuum dehydration in step (1) is 100-120°C and the time is 1-2h; the temperature of the neutralization reaction in step (3) is 50-70°C and the time is 40-60min; the speed of the high-speed stirring is 1000-1500r / min, and the stirring time is 30-40min.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The fluorosilicone waterborne polyurethane provided by the present invention effectively regulates the reaction activity during the prepolymer preparation process and the structure of the final polymer by designing and adopting a fluorosilicone chain extender with a specific structure, and successfully prepares a waterborne polyurethane dispersion with moderate viscosity, storage stability, and the ability to improve performance through subsequent cross-linking. This method overcomes the problems of the traditional prepolymer method that is difficult to prepare highly cross-linked waterborne polyurethanes and the direct application of aminosilicone that easily leads to gelation and hydrolysis, and provides a new technical approach for the preparation of high-performance waterborne polyurethanes.

[0031] (2) The fluorosilicone waterborne polyurethane provided by the present invention has an added siloxane chain extender, which, through molecular structure design, converts the highly active primary amino group in aminopropyltrimethoxysiloxane into a relatively mild secondary amino group with a relatively mild reaction activity, and at the same time introduces a highly hydrophobic fluorine-containing chain segment, which can significantly reduce the reaction rate of the chain extender in the synthesis of the polyurethane prepolymer, effectively avoid the gelation phenomenon caused by too fast a reaction, and ensure the smooth preparation of the prepolymer; at the same time, the introduction of the fluorocarbon chain also helps to improve the hydrophobicity of the polymer chain segment, thereby improving the hydrolysis sensitivity of the siloxane part, and improving the storage stability of the final waterborne polyurethane emulsion and the hydrolysis resistance of the cured material; in addition, the excellent weather resistance inherent in the fluorocarbon chain segment itself can significantly improve the resistance of the final polyurethane material to ultraviolet aging and chemical corrosion, thereby extending its service life.

[0032] (3) The fluorosilicone waterborne polyurethane provided by the present invention, by introducing a siloxane chain extender, not only helps to improve the flexibility of the polyurethane main chain and contributes to the increase of the molecular weight of the final polymer, but also improves the problems of low molecular weight and insufficient mechanical strength of the traditional prepolymer method waterborne polyurethane. Moreover, since the trimethoxysilane functional group is retained in the chain extender, after the waterborne polyurethane is formed into a film, these groups can trigger hydrolysis and condensation reactions under moisture or heating conditions to form a siloxane cross-linked network, so that the final polyurethane material has higher cross-linking density, hardness, wear resistance and chemical resistance; in addition, the presence of the silane group is also conducive to enhancing the interfacial interaction and chemical bonding between the polyurethane and the hydroxyl-containing inorganic substrate or filler (such as silica commonly used in sports field materials, etc.), thereby improving the overall performance and durability of the composite material. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from commercially purchased raw materials.

[0035] The hydroxyl-terminated polyacrylate was prepared according to the literature (Effect of Molecular Weight of Hydroxyl-Terminated Polyacrylate on PUA Properties, Chen Guangmei, Chen Wei, et al., Applied Chemical Industry, December 2011); the hydroxyl-terminated polyester was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd., item number PA98433; the hydroxyl-terminated polyether was Clariant's Polyglykol AB 25-8, with a number-average molecular weight of 1800; the bishydroxyl polyether was purchased from Real Madrid Technology's PPG1000, with a number-average molecular weight of 1000; the NCO content was determined according to Method A in GB12009.4-2016. Other hydroxyl-terminated polyethers were purchased from Haian Petrochemical.

[0036] Example 1

[0037] A fluorosilicone waterborne polyurethane comprising the following raw materials in parts by weight:

[0038] 230 parts of hydroxyl-terminated polyether with a number average molecular weight of 4000, 40 parts of isophorone diisocyanate, 10 parts of siloxane chain extender, 0.7 parts of dibutyltin dilaurate, 20 parts of dihydroxypropionic acid, 15 parts of triethylamine, and 550 parts of deionized water.

[0039] The preparation method of the siloxane chain extender comprises the following steps:

[0040] S1. Add 33.2 g of hexafluoropropylene oxide dimer to 500 mL of ether, then add 7.4 g of glycidol, and react at 27° C. with stirring for 13 h. After the reaction is completed, remove the solvent by distillation under reduced pressure to obtain hexafluoropropylene oxide dimer epoxy ester;

[0041] S2. Add 38.6 g of hexafluoropropylene oxide dimer epoxy ester and 17.9 g of aminopropyltrimethoxysiloxane into a three-necked flask, pass nitrogen gas through it, and react at a constant temperature of 23° C. for 4 hours to obtain a siloxane chain extender.

[0042] A method for preparing a fluorosilicone waterborne polyurethane, characterized by comprising the following steps:

[0043] (1) Add a hydroxyl-terminated polyether with a number average molecular weight of 4000 and dihydroxypropionic acid into a three-necked flask, dehydrate at 110° C. under vacuum conditions for 1.5 h, cool to below 40° C., then add isophorone diisocyanate and dibutyltin dilaurate, and stir to obtain a mixture;

[0044] (2) nitrogen was introduced into the mixture in step (1) under stirring conditions, and then the temperature was raised to 80° C. and kept warm for 2 hours. After the NCO content of the test system had decreased to the theoretical value, a siloxane chain extender was added and the temperature was continued to be kept warm until the NCO content was completely reacted to obtain a polyurethane prepolymer;

[0045] (3) triethylamine was added to the polyurethane prepolymer in step (2), and the mixture was neutralized at 60° C. for 50 min. After the reaction was completed, deionized water was slowly added under high-speed stirring at a speed of 1300 r / min for 35 min to form a stable emulsion.

[0046] Example 2

[0047] A fluorosilicone waterborne polyurethane comprising the following raw materials in parts by weight:

[0048] 190 parts of hydroxyl-terminated polyester with a number average molecular weight of 2000, 33 parts of dicyclohexylmethane-4,4'-diisocyanate, 7 parts of siloxane chain extender, 0.5 parts of stannous isooctanoate, 17 parts of dihydroxybutyric acid, 12 parts of triethylamine, and 450 parts of deionized water.

[0049] The preparation method of the siloxane chain extender comprises the following steps:

[0050] S1. Add 33.2 g of hexafluoropropylene oxide dimer to 500 mL of ether, then add 7.4 g of glycidol, and react at 27° C. with stirring for 12 h. After the reaction is completed, remove the solvent by distillation under reduced pressure to obtain hexafluoropropylene oxide dimer epoxy ester;

[0051] S2. Add 38.6 g of hexafluoropropylene oxide dimer epoxy ester and 17.9 g of aminopropyltrimethoxysiloxane into a three-necked flask, pass nitrogen gas through it, and react at a constant temperature of 23° C. for 4 hours to obtain a siloxane chain extender.

[0052] A method for preparing a fluorosilicone waterborne polyurethane, characterized by comprising the following steps:

[0053] (1) Adding a hydroxyl-terminated polyester with a number average molecular weight of 2000 and dihydroxybutyric acid into a three-necked flask, dehydrating the mixture at 110° C. for 1.5 h under vacuum conditions, cooling the mixture to below 40° C., then adding dicyclohexylmethane-4,4'-diisocyanate and stannous isooctanoate, and stirring the mixture to obtain a mixture;

[0054] (2) nitrogen was introduced into the mixture in step (1) under stirring conditions, and then the temperature was raised to 90° C. and kept warm for 2 hours. After the NCO content of the test system had decreased to the theoretical value, a siloxane chain extender was added and the temperature was continued to be kept warm until the NCO content was completely reacted to obtain a polyurethane prepolymer;

[0055] (3) triethylamine was added to the polyurethane prepolymer in step (2), and the mixture was neutralized at 60° C. for 50 min. After the reaction was completed, deionized water was slowly added under high-speed stirring at a speed of 1200 r / min for 35 min to form a stable emulsion.

[0056] Example 3

[0057] A fluorosilicone water-based polyurethane comprising the following raw materials in parts by weight:

[0058] 220 parts of hydroxy-terminated polyacrylate with a number average molecular weight of 3000, 38 parts of methylcyclohexane diisocyanate, 9 parts of siloxane chain extender, 0.6 parts of dibutyltin dilaurate, 18 parts of dihydroxypropionic acid, 13 parts of triethylamine, and 500 parts of deionized water.

[0059] The preparation method of the siloxane chain extender comprises the following steps:

[0060] S1. Add 33.2 g of hexafluoropropylene oxide dimer to 500 mL of ether, then add 7.4 g of glycidol, and react at 25° C. with stirring for 15 h. After the reaction is completed, remove the solvent by distillation under reduced pressure to obtain hexafluoropropylene oxide dimer epoxy ester;

[0061] S2. Add 38.6 g of hexafluoropropylene oxide dimer epoxy ester and 17.9 g of aminopropyltrimethoxysiloxane into a three-necked flask, pass nitrogen gas through it, and react at a constant temperature of 20° C. for 5 h to obtain a siloxane chain extender.

[0062] A method for preparing a fluorosilicone waterborne polyurethane, characterized by comprising the following steps:

[0063] (1) Add hydroxyl-terminated polyacrylate with a number average molecular weight of 3000 and dihydroxypropionic acid into a three-necked flask, dehydrate at 100°C for 2 h under vacuum conditions, cool to below 40°C, then add methylcyclohexane diisocyanate and dibutyltin dilaurate, and stir to obtain a mixture;

[0064] (2) nitrogen was introduced into the mixture in step (1) under stirring conditions, and then the temperature was raised to 60° C. and kept warm for 3 hours. After the NCO content of the test system had decreased to the theoretical value, a siloxane chain extender was added and the temperature was continued to be kept warm until the NCO content was completely reacted to obtain a polyurethane prepolymer;

[0065] (3) adding triethylamine to the polyurethane prepolymer in step (2) and carrying out a neutralization reaction at 50° C. for 60 min. After the reaction is completed, deionized water is slowly added under high-speed stirring at a speed of 1000 r / min for 40 min to form a stable emulsion.

[0066] Example 4

[0067] A fluorosilicone water-based polyurethane comprising the following raw materials in parts by weight:

[0068] 180 parts of hydroxyl-terminated polyether with a number average molecular weight of 2000, 30 parts of diphenylmethane-4,4'-diisocyanate, 6 parts of siloxane chain extender, 0.4 parts of stannous isooctanoate, 15 parts of dihydroxybutyric acid, 10 parts of triethylamine, and 400 parts of deionized water.

[0069] The preparation method of the siloxane chain extender comprises the following steps:

[0070] S1. Add 33.2 g of hexafluoropropylene oxide dimer to 500 mL of ether, then add 7.4 g of glycidol, and react at 30° C. with stirring for 10 h. After the reaction is completed, remove the solvent by distillation under reduced pressure to obtain hexafluoropropylene oxide dimer epoxy ester;

[0071] S2. Add 38.6 g of hexafluoropropylene oxide dimer epoxy ester and 17.9 g of aminopropyltrimethoxysiloxane into a three-necked flask, pass nitrogen gas through it, and react at a constant temperature of 25° C. for 3 h to obtain a siloxane chain extender.

[0072] A method for preparing a fluorosilicone waterborne polyurethane, characterized by comprising the following steps:

[0073] (1) Add a hydroxyl-terminated polyether with a number average molecular weight of 2000 and dihydroxybutyric acid into a three-necked flask, dehydrate at 120° C. for 1 h under vacuum conditions, cool to below 40° C., then add diphenylmethane-4,4'-diisocyanate and stannous isooctanoate, and stir to obtain a mixture;

[0074] (2) nitrogen was introduced into the mixture in step (1) under stirring conditions, and then the temperature was raised to 100° C. and kept warm for 1 hour. After the NCO content of the test system had decreased to the theoretical value, a siloxane chain extender was added and the temperature was continued to be kept warm until the NCO content was completely reacted to obtain a polyurethane prepolymer;

[0075] (3) The polyurethane prepolymer in step (2) was added with triethylamine and neutralized at 70° C. for 40 min. After the reaction was completed, deionized water was slowly added under high-speed stirring at a speed of 1500 r / min for 30 min to form a stable emulsion.

[0076] Comparative Example 1

[0077] A fluorosilicone water-based polyurethane comprising the following raw materials in parts by weight:

[0078] 230 parts of hydroxyl-terminated polyether with a number average molecular weight of 4000, 40 parts of isophorone diisocyanate, 10 parts of aminopropyltrimethoxysiloxane, 0.7 parts of dibutyltin dilaurate, 20 parts of dihydroxypropionic acid, 15 parts of triethylamine, and 550 parts of deionized water.

[0079] A method for preparing a fluorosilicone waterborne polyurethane, characterized by comprising the following steps:

[0080] (1) Add a hydroxyl-terminated polyether with a number average molecular weight of 4000 and dihydroxypropionic acid into a three-necked flask, dehydrate at 110° C. under vacuum conditions for 1.5 h, cool to below 40° C., then add isophorone diisocyanate and dibutyltin dilaurate, and stir to obtain a mixture;

[0081] (2) nitrogen was introduced into the mixture in step (1) under stirring conditions, and then the temperature was raised to 80° C. and kept warm for 2 hours. After the NCO content of the test system had dropped to the theoretical value, aminopropyltrimethoxysiloxane was added and the temperature was continued to be kept warm until the NCO content was completely reacted to obtain a polyurethane prepolymer;

[0082] (3) triethylamine was added to the polyurethane prepolymer in step (2), and the mixture was neutralized at 60° C. for 50 min. After the reaction was completed, deionized water was slowly added under high-speed stirring at a speed of 1300 r / min for 35 min to form a stable emulsion.

[0083] Compared with Example 1, the chain extender in this comparative example is aminopropyltrimethoxysiloxane.

[0084] The fluorosilicone waterborne polyurethanes prepared in Examples 1-4 and Comparative Example 1 were subjected to performance tests to test their viscosity and storage stability at room temperature (6 months). They were cured at 60° C. for 4 h, and the tensile strength of the cured films was tested. The test results are shown in Table 1 below.

[0085] Table 1

[0086] Viscosity (cp) Storage stability (6 months) Tensile strength (MPa) Example 1 4500 5000 8.36 Example 2 4200 4800 8.11 Example 3 4300 4700 7.84 Example 4 4700 5300 8.25 Comparative Example 1 9700 Non-flowable, gel 7.19

[0087] As can be seen from Table 1 above, the fluorosilicone waterborne polyurethane prepared in the present invention has moderate viscosity and good storage stability. It also has good mechanical properties after curing and has good application prospects.

[0088] The above content is a further detailed description of the present invention in combination with specific implementation examples. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

[0089] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fluorosilicone waterborne polyurethane, characterized in that: Calculated by weight, it includes the following raw materials: 180-230 parts of terminal hydroxyl compound, 30-40 parts of polyisocyanate, 6-10 parts of siloxane chain extender, 0.4-0.7 parts of catalyst, 15-20 parts of hydrophilic monomer, 10-15 parts of triethylamine, and 400-550 parts of deionized water.

2. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that The terminal hydroxyl compound is one or more of terminal hydroxyl polyacrylate, terminal hydroxyl polyester, and terminal hydroxyl polyether; the polyisocyanate is one or more of diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hexamethylene diisocyanate trimer, tetramethyl-m-xylylene diisocyanate, and methylcyclohexane diisocyanate.

3. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that The catalyst is one or more of dibutyltin dilaurate, stannous isooctanoate, zinc isooctanoate, and bismuth isooctanoate.

4. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that The hydrophilic monomer is one or both of dihydroxypropionic acid and dihydroxybutyric acid.

5. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that The structural formula of the siloxane chain extender is as follows:

6. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that The preparation method of the siloxane chain extender comprises the following steps: S1, adding hexafluoropropylene oxide dimer to diethyl ether, then adding glycidol, stirring and reacting, and removing the solvent by reduced pressure distillation after the reaction is completed to obtain hexafluoropropylene oxide dimer epoxy ester; S2. Hexafluoropropylene oxide dimer epoxy ester and aminopropyl trimethoxysiloxane were added to a three-necked flask, nitrogen was introduced, and a constant temperature reaction was carried out to obtain a siloxane chain extender.

7. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that In step S1, the molar ratio of hexafluoropropylene oxide dimer to glycidol is 1:1, the stirring reaction temperature is 25-30° C., and the time is 10-15 hours.

8. The fluorosilicone waterborne polyurethane according to claim 1, characterized in that: In step S2, the molar ratio of hexafluoropropylene oxide dimer epoxy ester to aminopropyl trimethoxysiloxane is 1:1, and the stirring reaction temperature is 20-25° C. and the time is 3-5 hours.

9. A method for preparing the fluorosilicone waterborne polyurethane according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Adding a terminal hydroxy compound and a hydrophilic monomer to a three-necked flask, dehydrating under vacuum conditions, cooling to below 40° C., then adding a polyisocyanate and a catalyst, and stirring to obtain a mixture; (2) nitrogen is introduced into the mixture in step (1) under stirring conditions, and then the temperature is raised to 60-100° C. and kept warm for 1-3 hours. After the NCO content of the test system has been reduced to the theoretical value, a siloxane chain extender is added and the temperature is continued to be kept warm until the NCO content is completely reacted to obtain a polyurethane prepolymer; (3) adding triethylamine to the polyurethane prepolymer in step (2) to carry out a neutralization reaction, and slowly adding deionized water under high-speed stirring after the reaction is completed to form a stable emulsion.

10. The preparation method according to claim 9, characterized in that The temperature of the vacuum dehydration in step (1) is 100-120° C. and the time is 1-2 h; the temperature of the neutralization reaction in step (3) is 50-70° C. and the time is 40-60 min; the speed of the high-speed stirring is 1000-1500 r / min and the stirring time is 30-40 min.

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