A fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion, a preparation method and application thereof

Abstract

The application discloses a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion and a preparation method and application thereof, and belongs to the technical field of polyurethane emulsion synthesis. The preparation method comprises the following steps: reacting poly-1,4-butanediol adipate, dihydroxyl-terminated polysiloxane and diisocyanate under the action of a catalyst to obtain a prepolymer; adding a hydrophilic chain extender, a small-molecule dihydric alcohol chain extender and a crosslinking agent, a fluorine-containing end-capping agent and a neutralizing agent into the prepolymer in sequence to obtain a polymerization product through reaction; adding water into the polymerization product, performing high-speed shearing emulsification, and performing rotary evaporation until no solvent drops, and the fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion is obtained. The fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion obtained through the preparation method has excellent dispersibility, colloid stability and extremely strong adhesion, the latex film has excellent mechanical properties, hydrophobicity and anti-natural environment corrosion and chemical medium corrosion performance, and is expected to be applied in the fields of water-resistant coatings and water-resistant adhesives.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane emulsion synthesis, and particularly relates to a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion, a preparation method and application thereof. BACKGROUND

[0002] The information disclosed in the background of the present application is only intended to increase the understanding of the overall background of the present application and should not necessarily be regarded as acknowledging or implicitly suggesting that this information constitutes prior art known to those skilled in the art.

[0003] Waterborne polyurethane is a new type of polyurethane product which uses water instead of traditional organic solvents as a dispersion medium. With the advantages of green environmental protection, safety and good film forming performance, it is gradually replacing traditional organic solvent type polyurethane and is applied in daily life. However, the waterborne polyurethane segment is mostly linear structure and contains rich hydrophilic groups, which makes the waterborne polyurethane film lower than the traditional organic solvent type polyurethane in mechanical properties, hydrophobic properties and corrosion resistance.

[0004] The fluorosilicon composite modified waterborne polyurethane emulsion reported in the prior art generally has poor adhesion performance, and the emulsion film is difficult to simultaneously satisfy high mechanical properties and high corrosion resistance after film formation. Therefore, it is an urgent problem to be solved to provide a fluorosilicon composite modified waterborne polyurethane emulsion with strong adhesion performance, strong mechanical properties and high corrosion resistance by adjusting the types and contents of fluorine-containing alcohol and polysiloxane. SUMMARY

[0005] Therefore, the present application provides a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion, a preparation method and application thereof. The fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion provided by the present application not only has excellent dispersibility and colloidal stability, but also exhibits extremely strong adhesion performance. The waterborne polyurethane film prepared by using the emulsion exhibits excellent mechanical properties, and also exhibits excellent hydrophobicity and corrosion resistance to natural environment and chemical medium.

[0006] In a first aspect, the present application provides a preparation method of a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion, comprising the following steps:

[0007] Under an inert atmosphere, a prepolymer is obtained by reacting poly-1,4-butanediol adipate, dihydroxyl-terminated polysiloxane and diisocyanate under the action of a catalyst; a hydrophilic chain extender is added to the prepolymer and then reacted, followed by adding a small molecule dihydric alcohol chain extender and a crosslinking agent for reaction, then adding a fluorine-containing end-capping agent for reaction, and finally adding a neutralizing agent, to obtain a polymerization product; water is added to the polymerization product, high-speed shearing emulsification is performed, and rotary evaporation is performed until no solvent drops, to obtain the fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion.

[0008] The amount of the dihydroxyl-terminated polysiloxane is 4-6wt% of the total mass of the raw materials of the polymerization product.

[0009] Preferably, the number average molecular weight of the poly-1,4-butanediol adipate is 1500-2500 Da; the molecular weight of the dihydroxyl-terminated polysiloxane is 1000-3000 Da, and the viscosity is 600-1000 mPa·s.

[0010] Preferably, the mass ratio of the poly-1,4-butanediol adipate, diisocyanate, catalyst, hydrophilic chain extender, small molecule diol chain extender, crosslinking agent, fluorine-containing end-capping agent, and neutralizing agent is (43-47):(28-34):(0.01-0.02):(3-6):(2.5-4):(0.8-1.5):(5-7):(3-4).

[0011] Preferably, the diisocyanate is selected from one or more of isophorone diisocyanate, 4,4-diisocyanate dicyclohexyl methane, or toluene diisocyanate.

[0012] Preferably, the catalyst is selected from one or more of dibutyltin dilaurate, monobutyl tin oxide, dibutyl tin oxide, and dibutyl tin diacetate.

[0013] Preferably, the hydrophilic chain extender is selected from one or more of dimethylol propanoic acid, dimethylol butanoic acid, and 3,4-dihydroxyphenyl propanoic acid.

[0014] Preferably, the hydrophilic chain extender is first dissolved in an organic solvent, and then added to the prepolymer; the organic solvent is selected from one or more of acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, or methyl formate; and the amount ratio of the hydrophilic chain extender and the organic solvent is (2-4) g:10 mL.

[0015] Preferably, the crosslinking agent is selected from one or more of trimethylolpropane, glycerol, pentaerythritol, or butanetetrol.

[0016] Preferably, the small molecule diol chain extender is selected from one or more of 1,4-butanediol, ethylene glycol, diethylene glycol, pentanediol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, or 1,6-hexanediol.

[0017] Preferably, the fluorine-containing end-capping agent is selected from one or more of 1H,1H,2H,2H-perfluoro-1-octanol, hexafluoroisopropyl alcohol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, or 1H,1H,2H,2H-perfluoro-1-decanol.

[0018] Preferably, the neutralizing agent is one or more of trimethylamine, triethylamine, tributylamine, and triethanolamine.

[0019] Preferably, the diisocyanate is isophorone diisocyanate; the catalyst is dibutyl tin dilaurate; the hydrophilic chain extender is dimethylol propionic acid; the crosslinking agent is trimethylol propane; the small molecule diol chain extender is selected from 1,4-butanediol; and the fluorine-containing end-capping agent is 1H,1H,2H,2H-perfluoro-1-octanol.

[0020] Preferably, the inert atmosphere is selected from one or more of nitrogen, argon, helium or neon.

[0021] Preferably, in the step of reacting to obtain the prepolymer under the action of the catalyst, the reaction temperature is 70-90℃, and the reaction time is 80-110 min; in the step of reacting after adding the hydrophilic chain extender, the reaction temperature is 70-90℃, and the reaction time is 110-140 min; in the step of reacting after adding the small molecule diol chain extender and the crosslinking agent, the reaction temperature is 70-90℃, and the reaction time is 80-110 min; 110-140 min; in the step of reacting after adding the fluorine-containing end-capping agent, the reaction temperature is 70-90℃, and the reaction time is 110-140 min; and in the step of obtaining the polymerization product, the reaction temperature is 40-50℃, and the reaction time is 50-70 min.

[0022] Preferably, in the step of adding water to the polymerization product, the mass ratio of the polymerization product to water is 3:(6-8).

[0023] Preferably, the rotation speed of the high-speed shearing emulsification is 8000-12000 r / min, and the time of the high-speed shearing emulsification is 8-15 min.

[0024] Preferably, the temperature of the rotary evaporation is 45-55℃.

[0025] In a second aspect, the present application provides a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion prepared by the above preparation method.

[0026] In a third aspect, the present application provides an application of the above fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion as a water-resistant coating or a water-resistant adhesive.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] (1) The present application uses polybutylene adipate and dihydroxy-terminated polysiloxane together as the soft segment of the water-based polyurethane, uses the segment formed by diisocyanate, hydrophilic chain extender and small molecular diol chain extender as the hard segment, and uses hydrophobic fluorine-containing monomer as the end-capping agent, so that the fluorosilicon composite modified hyperbranched water-based polyurethane emulsion is prepared by high-speed shearing emulsification method after polymerization, the preparation method of the present application greatly reduces the amount of organic solvent, greatly reduces the production cost and the harm of reactants to human health and natural environment while ensuring the performance of the product, and the whole production process of the product does not involve high temperature and high pressure reaction, the production scheme is scientific and reasonable, and the production process is safe and reliable.

[0029] (2) The fluorosilicon composite modified hyperbranched water-based polyurethane emulsion obtained by the preparation method of the present application has excellent dispersibility and colloidal stability, and also exhibits extremely strong adhesion performance, the water-based polyurethane emulsion film prepared by using the water-based polyurethane emulsion exhibits excellent mechanical properties, and also exhibits excellent hydrophobicity and corrosion resistance to natural environment and chemical medium (including acid, alkali and salt), which is expected to greatly expand its application in the field of water-resistant coatings and water-resistant adhesives. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, the schematic embodiments of the present application and the description thereof serve to explain the present application, and do not constitute undue limitation on the present application. Obviously, other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0031] Figure 1 is a structural formula schematic diagram of the polymerization product in example 1 of the present application;

[0032] Figure 2 is an infrared spectrum diagram of the water-based polyurethane emulsion of example 1 and comparative examples 1-5 of the present application;

[0033] Figure 3 is the anti-graffiti performance determination picture of the water-based polyurethane emulsion film of example 1 of the present application;

[0034] Figure 4 is the adhesion performance determination picture of the FSiWPU5 emulsion of example 1 of the present application. DETAILED DESCRIPTION

[0035] It should be pointed out that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0036] The application provides a preparation method of fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion, and comprises the following steps:

[0037] Under an inert atmosphere, poly-1,4-butanediol adipate, dihydroxy-terminated polysiloxane and diisocyanate are reacted under the action of a catalyst to obtain a prepolymer; a hydrophilic chain extender is added to the prepolymer for reaction, then a small-molecule dihydric alcohol chain extender and a crosslinking agent are added for reaction, a fluorine-containing end-capping agent is added for reaction, and finally a neutralizing agent is added, so that a polymerization product is obtained; water is added to the polymerization product, high-speed shearing emulsification is performed, and rotary evaporation is performed until no solvent drops, so that the fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion is obtained.

[0038] The addition amount of the dihydroxy-terminated polysiloxane is 4-6 wt% of the total mass of raw materials of the polymerization product.

[0039] In the application, the polymerization product is synthesized by using a step-by-step polymerization method, which can maintain a small emulsion particle size, ensure the stability of the emulsion while ensuring the excellent performance of the waterborne polyurethane coating or film. The dihydroxy-terminated polysiloxane and the fluorine-containing end-capping agent are introduced to modify the waterborne polyurethane, and the obtained emulsion has high emulsion stability and high adhesion, and the latex film prepared therefrom has high strength, high toughness, high water resistance, high chemical corrosion resistance and excellent anti-graffiti performance.

[0040] The application finds that the addition amount of the dihydroxy-terminated polysiloxane has a significant influence on the fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion obtained finally, the appropriate addition of the dihydroxy-terminated polysiloxane can greatly improve the adhesion of the emulsion, and the strength, toughness, hydrophobicity and chemical corrosion resistance of the latex film are all improved; however, too much addition of the dihydroxy-terminated polysiloxane will adversely affect the performance in all aspects, and even the performance in the strength, hydrophobicity and chemical corrosion resistance is worse than that of the emulsion without the dihydroxy-terminated polysiloxane, therefore, the application limits the addition amount of the dihydroxy-terminated polysiloxane to 4-6 wt% of the total mass of raw materials of the polymerization product, and more preferably 5 wt%.

[0041] It should be noted that the "total mass of raw materials of the polymerization product" refers to the total mass of poly-1,4-butanediol adipate, dihydroxy-terminated polysiloxane, diisocyanate, a catalyst, a hydrophilic chain extender, a small-molecule dihydric alcohol chain extender, a crosslinking agent, a fluorine-containing end-capping agent and a neutralizing agent.

[0042] In the application, the number average molecular weight of the poly-1,4-butanediol adipate is 1500-2500 Da; the molecular weight of the dihydroxy-terminated polysiloxane is 1000-3000 Da, and the viscosity is 600-1000 mPa·s.

[0043] In the present application, the mass ratio of the poly(1,4-butanediol adipate), diisocyanate, catalyst, hydrophilic chain extender, small molecule diol chain extender, crosslinking agent, fluorine-containing end-capping agent and neutralizing agent is (43-47):(28-34):(0.01-0.02):(3-6):(2.5-4):(0.8-1.5):(5-7):(3-4).

[0044] In the present application, the diisocyanate is selected from one or more of isophorone diisocyanate, 4,4-diisocyanate dicyclohexyl methane or toluene diisocyanate, and isophorone diisocyanate is more preferable.

[0045] In the present application, the catalyst is selected from one or more of dibutyl tin dilaurate, monobutyl tin oxide, dibutyl tin oxide, dibutyl tin diacetate, and dibutyl tin dilaurate is more preferable.

[0046] In the present application, the hydrophilic chain extender is selected from one or more of dimethylol propanoic acid, dimethylol butanoic acid, 1,2-propanediol-3-sodium sulfonate, N-methyl-N,N di(2-hydroxyethyl) betaine or 1,4-butanediol-2-sodium sulfonate, and dimethylol propanoic acid is more preferable.

[0047] In the present application, since the hydrophilic chain extender is usually solid, the hydrophilic chain extender is first dissolved in an organic solvent, and then added to the prepolymer; the organic solvent is selected from one or more of acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran or methyl formate, and acetone is more preferable. The amount ratio of the hydrophilic chain extender and the organic solvent is (2-4) g:10 mL. The boiling point of the selected organic solvent in the present application is lower than that of water, which can be removed in the subsequent rotary evaporation process. In the present application, the organic solvent can be added to the system to maintain a suitable viscosity during the reaction according to the viscosity, and the amount and step of addition are not specially limited, and the method commonly used in the art for controlling viscosity by adding organic solvent can be used.

[0048] In the present application, the crosslinking agent is selected from one or more of trimethylolpropane, glycerol, pentaerythritol or butanetetrol, and trimethylolpropane is more preferable, which has a lower melting point and is in a molten state at the temperature of the polymerization reaction, facilitating the reaction.

[0049] In the present application, the small molecule diol chain extender is selected from one or more of 1,4-butanediol, ethylene glycol, diethylene glycol, pentanediol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol or 1,6-hexanediol, and 1,4-butanediol is more preferable.

[0050] In the present application, the fluorine-containing end-capping agent is selected from one or more of 1H, 1H, 2H, 2H-perfluoro-1-octanol, hexafluoroisopropanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol or 1H, 1H, 2H, 2H-perfluoro-1-decanol, and is more preferably 1H, 1H, 2H, 2H-perfluoro-1-octanol.

[0051] In the present application, the neutralizing agent is one or more of trimethylamine, triethylamine, tributylamine or triethanolamine, and is more preferably triethylamine.

[0052] In the present application, the inert atmosphere is selected from one or more of nitrogen, argon, helium or neon, and is preferably nitrogen.

[0053] In the present application, in the step of reacting to obtain the prepolymer under the action of the catalyst, the reaction temperature is 70-90℃, and the reaction time is 80-110min; in the step of adding the hydrophilic chain extender and then reacting, the reaction temperature is 70-90℃, and the reaction time is 110-140min; in the step of adding the small-molecule dihydric alcohol chain extender and the crosslinking agent and then reacting, the reaction temperature is 70-90℃, and the reaction time is 80-110min or 110-140min; in the step of adding the fluorine-containing end-capping agent and then reacting, the reaction temperature is 70-90℃, and the reaction time is 110-140min; and in the step of obtaining the polymerization product, the reaction temperature is 40-50℃, and the reaction time is 50-70min.

[0054] In the present application, in the step of adding water to the polymerization product, the mass ratio of the polymerization product to water is 3:(6-8).

[0055] In the present application, the rotation speed of the high-speed shearing emulsification is 8000-12000r / min, and the time of the high-speed shearing emulsification is 8-15min.

[0056] In the present application, the temperature of the rotary evaporation is 45-55℃. The rotary evaporation is used to remove the organic solvent added in the system, and the temperature of the rotary evaporation can be determined by the boiling point of the selected organic solvent by those skilled in the art.

[0057] The present application also provides a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion prepared by the above preparation method. The fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion prepared by the present application has extremely strong adhesion and colloidal stability, and the latex film obtained therefrom has high strength, high toughness, high chemical resistance, high hydrophobicity and high anti-graffiti performance.

[0058] The present application also provides the application of the above fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion as a water-resistant coating or a water-resistant adhesive.

[0059] The technical solutions of the present application are further described below in combination with specific examples. In the following examples, the number average molecular weight of polybutylene adipate (PBA) is 2000 Da, the molecular weight of the dihydroxyl-terminated polysiloxane (PDMS) is 2000 Da, and the viscosity is 800 mPa·s.

[0060] Example 1

[0061] The present example provides a preparation method of a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion. The mass fraction of dihydroxyl-terminated polysiloxane in the raw materials is 5 wt%.

[0062] In a four-necked flask equipped with a thermometer, a mechanical stirring rod, a spherical condenser, and a nitrogen inlet, nitrogen was introduced for 20 min to ensure a nitrogen atmosphere in the flask. After the temperature of the oil bath was raised to 80℃, 27.0 g of polybutylene adipate (PBA), 3.0 g of dihydroxyl-terminated polysiloxane (PDMS), 18.54 g of isophorone diisocyanate (IPDI), and 0.01 g of dibutyltin dilaurate (DBTDL) were added. The reaction was continued at 80℃ for 90 min to obtain a prepolymer. Then, 2.67 g of dimethylol propionic acid (DMPA) and 10 mL of acetone were added, and the reaction was continued at 80℃ for 120 min. Then, 1.90 g of 1,4-butanediol (BDO) and 0.59 g of trimethylolpropane (TMP) were added, and the reaction was continued at 80℃ for 90 min. Then, 3.56 g of 1H,1H,2H,2H-perfluoro-1-octanol was added, and the reaction was continued at 80℃ for 120 min. The -NCO of the system was measured by the di-n-butylamine method. When the theoretical requirement was reached, the temperature of the system was reduced to 45℃, 2.02 g of triethylamine was added, and the reaction was continued at 45℃ for 60 min to obtain a polymerization product. The total amount of acetone used in the entire synthesis process was about 35 mL. The structural formula of the polymerization product in this example is shown in Figure 1 .

[0063] Then, 50.00 g of the polymerization product was transferred to a beaker, 116.67 g of deionized water was added, and the emulsification was carried out at room temperature using a high-speed shearing emulsifier at a speed of 9000 r / min for 10 min. Then, the emulsified product was rotary evaporated at 50℃ until no solvent dropped to obtain a waterborne polyurethane emulsion, which was recorded as FSiWPU5, and the R value (the ratio of isocyanate groups to hydroxyl groups) was 1.3.

[0064] Example 2

[0065] The present example provides a preparation method of a fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion.

[0066] In a four-necked flask equipped with a thermometer, a mechanical stirring bar, a spherical condenser and a nitrogen inlet, nitrogen was bubbled for 20 min to ensure a nitrogen atmosphere in the flask. After the temperature of the oil bath was raised to 80°C, 27.0 g of polybutylene adipate (PBA), 3.0 g of dihydroxyl-terminated polysiloxane (PDMS), 18.54 g of toluene diisocyanate (TDI), 0.01 g of dibutyltin dilaurate (DBTDL) were added, and the reaction was continued at 80°C for 90 min to obtain a prepolymer. Then, 2.67 g of dimethylol butanoic acid (DMBA, dissolved in 10 mL of acetone) was added, and the reaction was continued at 80°C for 120 min. Then, 1.90 g of 1,4-butanediol (BDO) and 0.59 g of glycerol were added, and the reaction was continued at 80°C for 90 min. Then, 3.56 g of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol was added, and the reaction was continued at 80°C for 120 min. The -NCO content of the system was determined by the di-n-butylamine method. When the -NCO content reached the theoretical requirement, the temperature of the system was lowered to 45°C, 2.02 g of triethylamine was added, and the reaction was continued at 45°C for 60 min to obtain a polymerization product. The total amount of acetone used in the entire synthesis process was about 35 mL.

[0067] Then, 50.00 g of the polymerization product was transferred to a beaker, 116.67 g of deionized water was added, and the mixture was emulsified at room temperature for 10 min by using a high-speed shearing emulsifier. Then, the emulsified product was rotary evaporated at 50°C until no solvent droplets were observed to obtain an aqueous polyurethane emulsion.

[0068] Example 3

[0069] The present example provides a method for preparing a fluorosilicon composite modified hyperbranched aqueous polyurethane emulsion.

[0070] In a four-necked flask equipped with a thermometer, a mechanical stirrer, a spherical condenser and a nitrogen inlet, nitrogen was bubbled for 20 min to ensure a nitrogen atmosphere in the flask. After the temperature of the oil bath was raised to 80°C, 27.0 g of polybutylene adipate (PBA), 3.0 g of dihydroxyl-terminated polysiloxane (PDMS), 18.2 g of 4,4-diisocyanate dicyclohexyl methane (HMDI), 0.01 g of dibutyl tin oxide (DBTO) were added, and the reaction was continued at 80°C for 90 min to obtain a prepolymer. Then, 3.2 g of dimethylol propionic acid (DMPA, dissolved in 15 mL of acetone) was added, and the reaction was continued at 80°C for 120 min. Then, 1.80 g of ethylene glycol and 0.5 g of trimethylolpropane (TMP) were added, and the reaction was continued at 80°C for 90 min. Then, 3.56 g of hexafluoroisopropyl alcohol was added, and the reaction was continued at 80°C for 120 min. The -NCO of the system was measured by the di-n-butylamine method. When the theoretical requirement was reached, the temperature of the system was reduced to 45°C, 2.02 g of triethanolamine was added, and the reaction was continued at 45°C for 60 min to obtain a polymerization product. The total amount of acetone used in the entire synthesis process was about 40 mL.

[0071] Then, 50.00 g of the polymerization product was transferred to a beaker, 116.67 g of deionized water was added, and the emulsification was carried out at room temperature for 10 min by using a high-speed shearing emulsifier. Then, the emulsified product was rotary evaporated at 50°C until no solvent dropped to obtain a waterborne polyurethane emulsion.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that no dihydroxyl-terminated polysiloxane is added in the raw materials of this comparative example, and the missing amount is made up by polybutylene adipate. The specific difference is that 30.0 g of polybutylene adipate (PBA) and 0 g of dihydroxyl-terminated polysiloxane (PDMS) are added in this comparative example, and the obtained fluorine-modified hyperbranched waterborne polyurethane emulsion is denoted as FWPU, and the R value is 1.3.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 1 is that the mass fraction of dihydroxyl-terminated polysiloxane in the raw materials of this comparative example is 10 wt%. The specific difference is that 24.0 g of polybutylene adipate (PBA) and 6.0 g of dihydroxyl-terminated polysiloxane (PDMS) are added in this comparative example, and the obtained fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion is denoted as FSiWPU10, and the R value is 1.3.

[0076] Comparative Example 3

[0077] The comparative example is compared with example 1, the difference is that the mass fraction of dihydroxyl-terminated polysiloxane in the raw materials of the comparative example is 15wt%, and the specific difference is that the comparative example adds 21.0g of poly-1,4-butanediol adipate (PBA), 9.0g of dihydroxyl-terminated polysiloxane (PDMS), and the obtained fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion is recorded as FSiWPU15, and the R value is 1.3.

[0078] Comparative example 4

[0079] The comparative example is compared with example 1, the difference is that the mass fraction of dihydroxyl-terminated polysiloxane in the raw materials of the comparative example is 20wt%, and the specific difference is that the comparative example adds 18.0g of poly-1,4-butanediol adipate (PBA), 12.0g of dihydroxyl-terminated polysiloxane (PDMS), and the obtained fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion is recorded as FSiWPU20, and the R value is 1.3.

[0080] Comparative example 5

[0081] The comparative example is compared with example 1, the difference is that the mass fraction of dihydroxyl-terminated polysiloxane in the raw materials of the comparative example is 20wt%, and the specific difference is that the comparative example adds 18.0g of poly-1,4-butanediol adipate (PBA), 12.0g of dihydroxyl-terminated polysiloxane (PDMS), and the obtained fluorosilicon composite modified hyperbranched waterborne polyurethane emulsion is recorded as FSiWPU20, and the R value is 1.3.

[0082] In a four-necked flask equipped with a thermometer, a mechanical stirring rod, a spherical condenser and a nitrogen inlet, nitrogen was introduced for 20 minutes to ensure that the flask was in a nitrogen atmosphere. After the temperature of the oil bath was raised to 80°C, 27.0g of poly-1,4-butanediol adipate (PBA), 3.0g of dihydroxyl-terminated polysiloxane (PDMS), 16.71g of isophorone diisocyanate (IPDI), and 0.01g of dibutyltin dilaurate (DBTDL) were added. The reaction was continued at 80°C for 90 minutes to obtain a prepolymer. Then 2.39g of dimethylol propionic acid (DMPA, dissolved in 35mL of acetone) was added and the reaction was continued at 80°C for 120 minutes. Then 1.70g of 1,4-butanediol (BDO) and 0.53g of trimethylolpropane (TMP) were added and the reaction was continued at 80°C for 90 minutes. The -NCO content of the system was measured by the di-n-butylamine method. When the theoretical requirement was reached, the temperature of the system was lowered to 45°C, 1.81g of triethylamine was added, and the reaction was continued at 45°C for 60 minutes to obtain a polymer product.

[0083] Then 50.00g of the polymer product was transferred to a beaker, 116.67g of deionized water was added, and the emulsion was emulsified at room temperature for 10 minutes using a high-speed shear emulsifier. Then the emulsified product was rotary evaporated at 50°C until no solvent droplets were observed to obtain a waterborne polyurethane emulsion, recorded as SiWPU5, and the R value was 1.3.

[0084] Test example

[0085] 1. The infrared spectrum of the dried waterborne polyurethane emulsion of Example 1 and Comparative Examples 1-5 was determined:

[0086] The infrared spectrum of each sample is shown in Figure 1, and the vibration absorption peaks are as follows: Figure 2 No vibration absorption peak appeared at about 2270 cm -1 , indicating that the -NCO groups had reacted completely; 3357 cm -1 was the -N-H stretching vibration absorption peak; 2923-2850 cm -1 corresponded to the C-H symmetric and asymmetric absorption peaks of CH2 groups; 1723 cm -1 was the C=0 stretching vibration absorption peak; 1161 cm -1 was the C-O-C asymmetric stretching vibration absorption peak; 1243 cm -1 was the C-F stretching vibration peak; 1099 cm -1 was the characteristic absorption peak of Si-O-Si, and 801 cm -1 was the characteristic absorption peak of Si-CH3. The typical waterborne polyurethane absorption peaks appeared in the infrared spectrum, which proved that the waterborne polyurethane was successfully prepared and that the polysiloxane and fluorocarbon groups were successfully introduced into the system.

[0087] 2. The physical properties of the waterborne polyurethane emulsion of Example 1 and Comparative Examples 1-5 were determined:

[0088] The test results are shown in Table 1. The fluorosilicone waterborne polyurethane emulsion was placed in a centrifuge tube and centrifuged at 3500 r / min for 15 min, and no layering appeared, indicating that it had excellent colloidal stability. After six months, no precipitation or demulsification occurred, indicating that it had long-term stability. The adhesion of the waterborne polyurethane did not change with the change in the content of polysiloxane, and it had good adhesion performance. Due to the flexibility of polysiloxane itself, the pencil hardness of the film decreased to some extent after the addition of polysiloxane.

[0089] Table 1 Physical property determination of waterborne polyurethane emulsion

[0090]

[0091] Note: In Table 1, the centrifugal stability determination method is: centrifuge the emulsion sample at a speed of 3500 r / min for 15 min, and if no layering appears, it means that it can exist stably; adhesion according to national standard GB / T9286-1998 "Paint and varnish - Crosshatch method for paint films"; pencil hardness according to national standard GB / T6739-1996 "Pencil hardness test method for coating film".

[0092] 3. The particle size distribution and PDI of the waterborne polyurethane emulsion of Example 1 and Comparative Examples 1-5 were determined:

[0093] Take 50 μl of aqueous polyurethane emulsion sample, dilute with deionized water to 8 ml, and then test the emulsion particle size distribution and polymer dispersion index (PDI) using a dynamic light scattering nanoparticle size analyzer at 25 °C. Three measurements were taken and the average value was recorded. The results are shown in Table 2.

[0094] Table 2 Average particle size and PDI of waterborne polyurethane emulsions

[0095]

[0096] As shown in Table 2, when the percentage of other monomers such as fluorinated alcohols in the fixed system remains unchanged, increasing the polysiloxane content from 0 wt% to 10 wt% increases the emulsion particle size from 38.58 nm to 55.85 nm, with little effect on the latex particle size. However, when the polysiloxane content continues to increase, the emulsion particle size increases sharply with the increase of polysiloxane percentage. When the polysiloxane addition is 15 wt%, the emulsion particle size reaches 88.30 nm. This is because after polysiloxane, as a hydrophobic monomer, is embedded in the main chain of waterborne polyurethane, it changes the ratio of hydrophilic and hydrophobic segments in the waterborne polyurethane chain. Furthermore, the Si-O-Si main chain in polysiloxane is covered by hydrophobic methyl side chains. Therefore, during emulsification, the hydrophobic polysiloxane coils inside the latex particles, while the hydrophilic groups wrap around the latex particles. Thus, with the increase of hydrophobic polysiloxane content, the particle size becomes larger and the distribution becomes uneven.

[0097] 4. Hydrophobic properties of the waterborne polyurethane emulsions and elemental analysis of the latex film surface in Examples 1 and Comparative Examples 1-5:

[0098] A certain amount of fluorosilicone waterborne polyurethane emulsion was weighed and poured into a polytetrafluoroethylene (PTFE) mold. After drying at room temperature for 48 hours, it was dried in an oven at 60°C for 24 hours to obtain a waterborne polyurethane film. A certain amount of fluorosilicone waterborne polyurethane emulsion was weighed and uniformly coated onto a tinplate. After drying at room temperature for 48 hours, it was dried in an oven at 60°C for 24 hours, resulting in a waterborne polyurethane film that adhered tightly to the tinplate. After film formation on the tinplate, the contact angle was tested using the seat drop method to characterize its hydrophobic properties. A 2cm x 2cm sample of the waterborne polyurethane film was cut from the PTFE mold, immersed in deionized water for 24 hours, and its water absorption rate was calculated. The results are shown in Table 3. A 0.5cm x 0.5cm sample was cut from the PTFE film, and the surface composition of the film was analyzed using X-ray photoelectron spectroscopy (XPS). The results are shown in Table 4.

[0099] Table 3 Contact Angle and Water Absorption Rate of Polyurethane Latex Film

[0100]

[0101] Table 4 Percentage of surface elements of the adhesive film (unit: %)

[0102]

[0103] As can be seen from Table 3 and Table 4, the water resistance of the adhesive film first increases and then decreases with the increase of the content of polysiloxane. When the polysiloxane is not introduced into the waterborne polyurethane segment, the contact angle of the adhesive film is 104.44°, and the water absorption rate is 5.60%; when the content of other monomers such as fluorine-containing alcohol in the system is fixed, the content of polysiloxane is increased from 0wt% to 5wt%, the contact angle of the adhesive film is increased to 113.56°, and the water absorption rate is reduced to 5.55%, and the water resistance of the adhesive film is improved to a certain extent; but when the content of polysiloxane continues to increase, the water resistance of the adhesive film decreases with the increase of the content of polysiloxane, and when the content of polysiloxane is 20wt%, the contact angle of the adhesive film reaches 94.91°, and the water absorption rate increases to 8.21%. In order to explain this phenomenon, the fluorosilicone waterborne polyurethane adhesive film is tested by XPS to determine the element composition of the film surface (Table 4), and it is found that the migration behavior of fluorine and silicon elements to the surface of the adhesive film during the film forming process is not a cooperative relationship but a competitive relationship. The embedded polysiloxane in the main chain will hinder the migration efficiency of the terminal fluorocarbon group. When the content of polysiloxane is increased from 0wt% to 5wt%, although the content of fluorine element on the surface of the adhesive film is slightly reduced, the migration of silicon element to the surface can make up for the blank of fluorine element, so the contact angle of the adhesive film does not decrease and slightly increases, and the water resistance of the adhesive film is improved; but when the content of polysiloxane continues to increase, the content of fluorine element on the surface of the adhesive film decreases sharply, the content of silicon element continues to rise and reaches saturation, and the ability of polysiloxane to reduce surface energy is lower than that of fluorocarbon group, so the contact angle and water absorption rate of the adhesive film decrease and increase respectively with the continuous increase of the content of polysiloxane, and the water resistance of the adhesive film decreases.

[0104] 5. Mechanical property determination of the waterborne polyurethane adhesive film of Example 1 and Comparative Examples 1-5:

[0105] The mechanical properties of the polyurethane adhesive film were tested according to GB / T16777-2008 standard. A certain amount of fluorosilicone waterborne polyurethane emulsion was poured into a polytetrafluoroethylene mold, dried at room temperature for 48h, and then dried in an oven at 60℃ for 24h to obtain the waterborne polyurethane adhesive film. The dumbbell-shaped sample was cut from the adhesive film with a dumbbell-shaped cutter, and the mechanical properties including tensile stress and elongation at break were tested by a universal material testing machine with a tensile rate of 50mm / min. The test results are shown in Table 5.

[0106] Table 5 Mechanical property determination of the polyurethane adhesive film

[0107]

[0108] As can be seen from Table 5, when the percentage content of other monomers such as fluorine-containing alcohol in the fixing system is unchanged, the tensile strength of the adhesive film first increases and then decreases with the increase of the polysiloxane content. When the percentage content of polysiloxane is 5wt%, the maximum tensile strength of the adhesive film is 62.82 MPa, the elongation at break is 757.75%, and the toughness is 211.43 MJ / m 3 , showing the best mechanical properties. This is because, in the process of forming the waterborne polyurethane emulsion film, the hard segment composed of isocyanate and chain extender and the soft segment composed of polyol have a tendency of spontaneous separation due to the difference in polarity and molecular motion deformation ability of the chain segment, forming a special aggregation structure, i.e. microphase separation. The addition of polysiloxane enhances the microphase separation of the adhesive film and improves the directional movement of the microphase segment under the action of external force in the stretching process, thereby improving the tensile strength of the adhesive film. When the percentage content of polysiloxane is greater than 5wt%, the mechanical properties show a downward trend. This is because too much polysiloxane leads to too strong microphase separation, thereby reducing the interaction force between the soft and hard segments, resulting in a decrease in the mechanical properties of the adhesive film.

[0109] 6. Thermal stability determination of the waterborne polyurethane emulsion film of Example 1 and Comparative Examples 1-5:

[0110] A certain amount of fluorosilicon waterborne polyurethane emulsion was poured into a polytetrafluoroethylene mold, dried at room temperature for 48h, and then dried in an oven at 60℃ for 24h to obtain a waterborne polyurethane adhesive film. 5-10mg of the sample was cut and heated from 25℃ to 600℃ at a heating rate of 20℃ / min under nitrogen atmosphere using a high-precision thermal gravimetric analyzer. The test results are shown in Table 6.

[0111] Table 6 Thermal stability of waterborne polyurethane emulsion film

[0112]

[0113] Note: In Table 6, T 10％ refers to the temperature at which 10% weight loss occurs, T 50％ refers to the temperature at which 50% weight loss occurs, and T 90％ refers to the temperature at which 90% weight loss occurs.

[0114] From Table 6, the thermal stability of the waterborne polyurethane adhesive film can be analyzed from two stages, the first stage is about 250-400°C, mainly the decomposition of the urethane bond in the chain segment with poor thermal stability; the second stage is about 400-600°C, mainly the decomposition of the soft segment macromolecular polyol. It can be seen that with the increase of polysiloxane content, the thermal stability of the waterborne polyurethane adhesive film in the second decomposition stage has a significant increase, because the high bond energy and high ionization tendency of Si-O bond make the polysiloxane segment can absorb more heat, enhance the thermal stability of the chain segment.

[0115] 7. Natural environment resistance and chemical resistance of the waterborne polyurethane adhesive film of Example 1 and Comparative Examples 1-5

[0116] A certain amount of fluorosilicone waterborne polyurethane emulsion was weighed and uniformly coated on a tin plate, and after drying at room temperature for 48 h and drying in an oven at 60°C for 24 h, the waterborne polyurethane formed a film on the tin plate and tightly adhered to the tin plate. After the film was formed on the tin plate, the tin plate was placed outdoors to experience the influence of the natural environment, and the corrosion resistance and natural environment resistance of the tin plate were tested. The test results are shown in Table 7.

[0117] Table 7 Natural environment resistance of the waterborne polyurethane adhesive film

[0118]

[0119] From the above test results, it can be seen that after 42 days of treatment, the film did not appear blistering, peeling and other phenomena, and played a good corrosion protection effect on the coated substrate, indicating that the prepared fluorosilicone waterborne polyurethane has excellent natural environment corrosion resistance and can be applied in metal corrosion protection.

[0120] A certain amount of fluorosilicone waterborne polyurethane emulsion was weighed and uniformly coated on a tin plate, and after drying at room temperature for 48 h and drying in an oven at 60°C for 24 h, the waterborne polyurethane formed a film on the tin plate and tightly adhered to the tin plate. After the film was formed on the tin plate, the tin plate was placed in 5% sulfuric acid solution (Table 8), 5% sodium chloride solution (Table 9), and 5% sodium bicarbonate solution (Table 10) respectively to test its chemical environment resistance.

[0121] Table 8 Acid resistance of the waterborne polyurethane adhesive film

[0122]

[0123]

[0124] Table 9 Salt resistance of the waterborne polyurethane adhesive film

[0125]

[0126] Table 10 Alkali resistance of waterborne polyurethane latex films

[0127]

[0128]

[0129] As can be seen from Tables 8 to 10, when the polysiloxane content is 5 wt% (Example 1), after immersion in 5% sulfuric acid or 5% sodium chloride solution for 30 days, the latex film did not exhibit blistering or peeling, indicating that it has excellent resistance to acid and salt chemical environments; after immersion in 5% sodium bicarbonate solution for 20 days, the film did not exhibit blistering or peeling, indicating that it has excellent resistance to alkali chemical environments.

[0130] 8. Anti-graffiti performance test of the waterborne polyurethane latex film in Example 1:

[0131] A certain amount of FSiWPU5 emulsion from Example 1 was weighed and uniformly coated onto a wooden board. After drying at room temperature for 48 hours, it was dried in an oven at 60°C for 24 hours, thus forming a waterborne polyurethane film on the wooden board to create a stain-resistant coating. The droplet flow behavior of two different liquids (orange juice and stained water) dropped onto the inclined stain-resistant coating was tested to study the coating's liquid oleophobicity and stain-resistant properties. A water-based pen anti-graffiti test was performed. The coating was fully marked and allowed to dry completely in a well-ventilated environment for one minute. After this, the markings were wiped off with a dry paper towel, and photographs were taken to record the appearance before and after erasure.

[0132] Test results are as follows Figure 3 As shown, orange juice and water can easily slide off the coating without leaving any trace, while when they slide off ordinary wood or wood coated with ordinary wood varnish, they leave obvious water stains. This contrast demonstrates that the prepared FSiWPU5 coating has excellent anti-fouling properties and can effectively protect the wood. Furthermore, anti-graffiti ability is also an important criterion for evaluating the anti-fouling performance of a coating. In this study, the anti-graffiti performance of the coating was judged by observing the shrinkage behavior of water-based marker ink. The images shown compare the shrinkage behavior of water-based marker ink on different substrates. It can be seen that the ink did not shrink on the wood or the varnished wood. Conversely, because the FSiWPU5 coating surface contains abundant low surface energy fluorine and silicon elements, the marker ink on the FSiWPU5 coated wood exhibited extremely obvious shrinkage behavior, and the ink could be easily wiped off with thin paper without leaving any visible traces, indicating that the coating has excellent anti-graffiti performance.

[0133] 9. Adhesion performance determination of aqueous polyurethane emulsions in Examples 1-2 (Examples 1 and 2):

[0134] Two tinplate pieces or wood boards were adhered together using the waterborne polyurethane emulsion of Example 1, Comparative Examples 1-2, with an adhered area of 2.5 cm 2 After the emulsion was dried, the adhesion performance of the emulsion was tested, and the testing process and results are shown in Figure 4 and Table 11.

[0135] Table 11 Adhesion performance of waterborne polyurethane emulsion

[0136]

[0137] After the emulsion of Example 1 was dried, 25.7 kg of an object could be successfully lifted, indicating that the emulsion had extremely strong adhesion performance. In addition, after the adhered tinplate pieces were immersed in water for 7 days and then taken out, 25.7 kg of a heavy object could still be easily lifted, proving that the emulsion had extremely strong water-resistant adhesion when used as an adhesive. In comparison with the other samples, the FSiWPU5 emulsion of Example 1 exhibited the best adhesion performance on both tinplate and wood boards, which was an unexpected performance and greatly expanded the application of waterborne polyurethane in adhesives, especially water-resistant adhesives.

[0138] In summary, when the percentage content of polysiloxane was 5wt%, the fluorosilicone waterborne polyurethane emulsion had a small particle size and could exist stably for a long time, the emulsion had unexpected adhesion performance; the tensile strength of the adhesive film formed after the emulsion was dried increased, and the mechanical properties were improved; the contact angle of the adhesive film increased while the water absorption rate decreased, and the hydrophobic properties were improved; the thermal stability of the adhesive film increased in the range of 400°C to 500°C; the adhesive film had excellent resistance to natural environmental corrosion and chemical medium (including acid, base and salt) corrosion. Considering comprehensively, when the percentage content of polysiloxane was 5wt%, the comprehensive performance of the fluorosilicone waterborne polyurethane system was the best.

[0139] The above only describes preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a fluorosilicone composite modified hyperbranched waterborne polyurethane emulsion, characterized in that, Includes the following steps: Under an inert atmosphere, poly(1,4-butanediol adipate), dihydroxy-terminated polysiloxane, and diisocyanate were reacted with a catalyst to obtain a prepolymer. A hydrophilic chain extender was added to the prepolymer and the reaction was carried out. Then, a small molecule diol chain extender and a crosslinking agent were added and the reaction was carried out. A fluorinated end-capping agent was added and the reaction was carried out. Finally, a neutralizing agent was added and the reaction was carried out to obtain the polymer product. Water is added to the polymer product, emulsified by high-speed shearing, and rotary evaporated until no solvent drips out, thus obtaining the product. The amount of the dihydroxy-terminated polysiloxane added is 5-6 wt% of the total mass of the raw materials of the polymer product; The mass ratio of poly(1,4-butanediol adipate), diisocyanate, catalyst, hydrophilic chain extender, small molecule diol chain extender, crosslinking agent, fluorinated end-capping agent and neutralizing agent is (43~47):(28~34):(0.01~0.02):(3~6):(2.5~4):(0.8~1.5):(5~7):(3~4).

2. The preparation method according to claim 1, characterized in that, The poly(1,4-butanediol adipate) has a number-average molecular weight of 1500-2500 Da; the dihydroxy-terminated polysiloxane has a molecular weight of 1000-3000 Da and a viscosity of 600-1000 mPa·s.

3. The preparation method according to claim 2, characterized in that, The diisocyanate is selected from one or more of isophorone diisocyanate, 4,4-diisocyanate dicyclohexylmethane, or toluene diisocyanate; The catalyst is selected from one or more of dibutyltin dilaurate, monobutyltin oxide, dibutyltin oxide, and dibutyltin diacetate; The hydrophilic chain extender is selected from one or more of dimethylolpropionic acid, dimethylolbutyric acid, sodium 1,2-propanediol-3-sulfonate, N-methyl-N,N-bis(2-hydroxyethyl)betaine, or sodium 1,4-butanediol-2-sulfonate.

4. The preparation method according to claim 1, characterized in that, The hydrophilic chain extender is first dissolved in an organic solvent and then added to the prepolymer; the organic solvent is selected from one or more of acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, dimethyl sulfoxide, tetrahydrofuran or methyl formate; the ratio of the hydrophilic chain extender to the organic solvent is (2~4) g: 10 mL.

5. The preparation method according to claim 4, characterized in that, The crosslinking agent is selected from one or more of trimethylolpropane, glycerol, pentaerythritol or butanetetraethanol. The small molecule diol chain extender is selected from one or more of 1,4-butanediol, ethylene glycol, diethylene glycol, pentanediol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, or 1,6-hexanediol; The fluorinated end-capping agent is selected from one or more of 1H,1H,2H,2H-perfluoro-1-octanol, hexafluoroisopropanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol or 1H,1H,2H,2H-perfluoro-1-decanol. The neutralizing agent is one or more of trimethylamine, triethylamine, tributylamine, and triethanolamine.

6. The preparation method according to claim 3, characterized in that, The inert atmosphere is selected from one or more of nitrogen, argon, helium, or neon; in the step of reacting to obtain the prepolymer under the action of a catalyst, the reaction temperature is 70-90℃ and the reaction time is 80-110 min; in the step of reacting after adding a hydrophilic chain extender, the reaction temperature is 70-90℃ and the reaction time is 110-140 min; in the step of reacting with a small molecule diol chain extender and a crosslinking agent, the reaction temperature is 70-90℃ and the reaction time is 80-110 min; in the step of reacting with a fluorinated end-capping agent, the reaction temperature is 70-90℃ and the reaction time is 110-140 min; in the step of reacting to obtain the polymer product, the reaction temperature is 40-50℃ and the reaction time is 50-70 min.

7. The preparation method according to claim 1, characterized in that, In the step of adding water to the polymer product, the mass ratio of polymer product to water is 3:(6~8); the rotation speed of the high-speed shear emulsification is 8000~12000 r / min, and the high-speed shear emulsification time is 8~15 min; the temperature of the rotary evaporation is 45~55℃.

8. The fluorosilicone composite modified hyperbranched waterborne polyurethane emulsion prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the fluorosilicone composite modified hyperbranched waterborne polyurethane emulsion as described in claim 8 as a water-resistant coating or water-resistant adhesive.

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