Bio-based polyurethane waterproof finishing agent as well as preparation method and application thereof

Abstract

The preparation method comprises the following steps: (1) reacting bio-based isocyanate with bio-based polyol under the action of a catalyst, adding a dye and a bio-based chain extender after the reaction is finished, continuing a chain extension reaction, adding a diluent and an end-capping reagent after the reaction is finished, and adding an initiator after the reaction is finished; carrying out a semi-terminated reaction to prepare a semi-terminated isocyanate intermediate; and (2) adding a hydrophobic modified monomer and an initiator into the reaction system in the step (1), adding an end-capping reagent to carry out an end-capping reaction after the polymerization reaction is finished, cooling after the reaction is finished, adding a neutralizer, and removing the diluent after the neutralization reaction is finished, thereby obtaining the bio-based waterborne polyurethane waterproof finishing agent. When the finishing agent is applied to the textile, the finished textile is soft in hand feeling and good in air permeability. The waterproof finishing agent not only can be used for waterproof finishing of textiles, but also can be used for waterproof finishing in the fields of umbrellas, tents, car paints, walls and the like.

Description

Technical Field

[0001] The invention relates to a bio-based polyurethane waterproof finishing agent and a preparation method and application thereof, belonging to the technical field of functional finishing of textiles. Background Art

[0002] Waterborne polyurethane is a polyurethane system that uses water instead of organic solvents as a dispersion medium. It is widely used due to its advantages such as no pollution, environmental friendliness, easy cleaning of residual glue, good compatibility, and easy modification. However, most of the synthetic materials of polyurethane currently come from petroleum resources. Over-reliance will aggravate resource waste. Due to the high pollution and shortage of petroleum resources, polyurethane materials are not conducive to environmental protection, and the cost continues to increase, which restricts its application development. With the development of green production, it is necessary to develop green and environmentally friendly waterborne polyurethane materials.

[0003] Bio-based polyurethane is a polyurethane material that is prepared by partially or completely using renewable biological resources (such as vegetable oils, biomass or other natural materials). Bio-based polyurethane replaces traditional petroleum-based raw materials by partially or completely using renewable biological resources, thereby achieving more environmentally friendly and sustainable material production. Bio-based polyurethane has been widely studied in the automotive industry, building materials, coatings and adhesives. With the advancement of technology and the growth of market demand, bio-based polyurethane is expected to be more widely used in the future.

[0004] Polyurethane waterproof coating is a coating process that forms an impermeable continuous film on the surface of fabric for waterproofing. However, the coating usually makes the fabric thick, hard and airtight, and requires the addition of various additives such as adhesives, which poses environmental problems and limits its application in textiles. In addition, the colorant in general waterproof coatings is usually dispersed in the color paste, which cannot be guaranteed to be evenly dispersed, resulting in color difference and poor migration resistance. Summary of the invention

[0005] [Technical issues]

[0006] The synthetic raw materials of polyurethane are mostly derived from petroleum resources, which is not conducive to environmental protection. Traditional textile waterproof coatings will cause the fabric to be thick, too hard to touch, and not breathable. In addition, additional additives such as adhesives need to be added, which is environmentally friendly. There will also be color differences and poor migration resistance.

[0007] [Technical solution]

[0008] In order to solve the above problems, the present invention application provides a bio-based polyurethane waterproof finishing agent and its preparation method and application. The colorant is anchored in the main chain of the waterborne polyurethane through chemical bonds to ensure the dye loading amount, and a hydrophobic modified monomer is introduced into the side chain to give the polyurethane hydrophobicity to achieve the purpose of waterproofing. The finishing agent has the characteristics of soft film-forming feel, good air permeability, good migration resistance, and uniform coloring, and no additional additives and dyeing are required, and the material is environmentally friendly. The invention can be widely used in the waterproof finishing of textiles such as swimsuits, umbrellas, and assault jackets. Compared with traditional waterproof finishing agents, it has the characteristics of soft feel, good air permeability, and is not easy to fade and has uniform coloring.

[0009] The technical solution adopted by the present invention is as follows:

[0010] The first object of the present invention is to provide a method for preparing a bio-based waterborne polyurethane waterproof finishing agent, comprising the following steps:

[0011] (1) bio-based isocyanate and bio-based polyol react under the action of a catalyst, and after the reaction, a dye and a bio-based chain extender are added to continue the chain extension reaction, and after the reaction, a diluent and a blocking agent are added to carry out a semi-blocking reaction to obtain a semi-blocked isocyanate intermediate;

[0012] (2) adding a hydrophobic modified monomer and an initiator to the reaction system of step (1), adding a capping agent to carry out a capping reaction after the polymerization reaction is completed, cooling the reaction after the reaction is completed, adding a neutralizing agent, and removing the diluent after the neutralization reaction is completed to obtain the bio-based waterborne polyurethane waterproof finishing agent;

[0013] The solid content of the bio-based waterborne polyurethane waterproof finishing agent is 10-60wt%.

[0014] In one embodiment of the present invention, in step (1), the bio-based isocyanate is one or more of toluene diisocyanate, dimer acid diisocyanate, 1,5-pentane diisocyanate, and lysine diisocyanate.

[0015] In one embodiment of the present invention, in step (1), the bio-based polyol is one or more of epoxidized tung oil alcoholysate (EGTO), rosin polyether polyol, castor oil-based polyol, rapeseed oil polyol, isosorbide-based polyester polyol, and wood fiber-based polyol.

[0016] In one embodiment of the present invention, in step (1), the average molecular weight of the bio-based polyol is 200-3000.

[0017] In one embodiment of the present invention, in step (1), the hydroxyl value of the biopolyol is 100-400 mg / g and the functionality is 2-4.

[0018] In one embodiment of the present invention, in step (1), the catalyst is one or more of stannous octoate, stannous oleate, dibutyltin dilaurate, triethylenediamine, dimethylethanolamine, N-methylmorpholine, and N,N-dimethylcyclohexylamine.

[0019] In one embodiment of the present invention, in step (1), the molar ratio of bio-based isocyanate to bio-based polyol is 2-6:1.

[0020] In one embodiment of the present invention, in step (1), the amount of catalyst used is 0.05-0.2% of the total mass of bio-based isocyanate and bio-based polyol.

[0021] In one embodiment of the present invention, in step (1), the dye is a dye containing amino or hydroxyl groups in its structure, including but not limited to one or more of Disperse Blue 14, Reactive Yellow 5, Disperse Red 19, Disperse Red 58, Acid Red 299, Disperse Black 9, and Disperse Red 64.

[0022] In one embodiment of the present invention, in step (1), the bio-based chain extender is one or more of sodium 1,2-dihydroxy-3-propanesulfonate, aminosulfonate (AAS-Na), sodium ethylenediaminesulfonate (X506), sodium N,N-di(2-hydroxyethyl)-2-aminoethanesulfonate, and sodium 1,2-dihydroxy-3-propyl ester sulfonate.

[0023] In one embodiment of the present invention, in step (1), the molar ratio of bio-based isocyanate to dye is 5-30:1; the molar ratio of bio-based isocyanate to bio-based chain extender is 8-25:1.

[0024] In one embodiment of the present invention, in step (1), the diluent is one or more of acetone, N,N-diformamide, and N-methylpyrrolidone; the capping agent is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, N,N-dimethylethanolamine (DMEA), and trimethylolpropane.

[0025] In one embodiment of the present invention, in step (1), the amount of the diluent is 50-150% of the total mass of the reactants; and the molar ratio of the capping agent to the bio-based isocyanate is 1:3-10.

[0026] In one embodiment of the present invention, in step (1), the conditions for the reaction of bio-based isocyanate and bio-based polyol are: 70-100° C., and the reaction time is 1-3 hours.

[0027] In one embodiment of the present invention, in step (1), the conditions for the chain extension reaction are: 70-100° C., and the reaction time is 2-6 hours.

[0028] In one embodiment of the present invention, in step (1), the conditions for the semi-end-capping reaction are: 50-80° C., and the reaction time is 1-2 h.

[0029] In one embodiment of the present invention, in step (2), the hydrophobically modified monomer is one or more of hexafluorobutyl methacrylate, dodecafluoroheptyl methacrylate, octadecyl methacrylate, and vinyl-terminated polydimethylsiloxane;

[0030] In one embodiment of the present invention, in step (2), the initiator is one or more of ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride.

[0031] In one embodiment of the present invention, in step (2), the molar ratio of the hydrophobically modified monomer to the end-capping agent is 1-10:10; and the amount of the initiator is 1-3% of the total mass of the hydrophobically modified monomer and the end-capping agent.

[0032] In one embodiment of the present invention, in step (2), the end-capping agent is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, N,N-dimethylethanolamine (DMEA), and trimethylolpropane.

[0033] In one embodiment of the present invention, in step (2), the neutralizing agent is one or more of triethylamine, ammonia water, hydrochloric acid, sodium hydroxide, and acetic acid.

[0034] In one embodiment of the present invention, in step (2), the molar ratio of the end-capping agent to the bio-based chain extender is 1:0.3-1.8; the molar ratio of the neutralizing agent to the bio-based chain extender is 0.5-1.5:1.

[0035] In one embodiment of the present invention, in step (2), the polymerization reaction conditions are: 60-80° C., and reaction time 6-8 h.

[0036] In one embodiment of the present invention, the conditions for the end-capping reaction are: 60-80° C., and the reaction time is 1-2 h.

[0037] In one embodiment of the present invention, the neutralization reaction conditions are: 50-60° C., and the reaction time is 0.5-1 h.

[0038] The second object of the present invention is to provide a bio-based waterborne polyurethane waterproof finishing agent prepared by the above preparation method.

[0039] The third object of the present invention is to provide an application of the above-mentioned bio-based water-based polyurethane waterproof finishing agent in textile finishing.

[0040] In one embodiment of the present invention, the bio-based waterborne polyurethane waterproof finishing agent is applied to textile fabrics by printing or spraying, with a thickness of 20-300 μm.

[0041] In one embodiment of the present invention, the printing method is screen printing, roller printing or digital inkjet printing.

[0042] In one embodiment of the present invention, the spraying method is to use a spray gun to spray on the fabric dried at room temperature at intervals of 20-30 cm, with a spraying speed of 30-60 cm / s, and spray in small amounts and multiple times to ensure the uniformity of the finishing agent coating.

[0043] The fourth object of the present invention is to provide a waterproof colored fabric finished with the above bio-based waterborne polyurethane waterproof finishing agent.

[0044] In one embodiment of the present invention, the above-mentioned bio-based waterborne polyurethane waterproof finishing agent is applied to textile fabrics by printing or spraying, and pre-baked at 50-70°C, and then baked at 130-200°C for 1-5 minutes to obtain a waterproof colored fabric.

[0045] In one embodiment of the present invention, the weight percentage of each component of the waterproof finishing paste for printing or spraying is: 5%-80% of bio-based water-based polyurethane waterproof finishing agent, 0-5% of thickener and the balance of deionized water, and the slurry viscosity is controlled at 100-1000cps.

[0046] In one embodiment of the present invention, a method for preparing a bio-based waterborne polyurethane waterproof finishing agent comprises the following steps:

[0047] Add bio-based isocyanate and bio-based polyol into a flask in a certain proportion, stir evenly at a certain speed, heat to 70-100°C, add catalyst, react for a period of time, slowly add dye and bio-based chain extender into the flask, react for 2-6 hours; cool to 50-80°C, add diluent, then add end-capping agent, and conduct semi-end-capping reaction for 1-2 hours;

[0048] Then raise the temperature to 60-80°C, add the hydrophobic modified monomer, mix well, add the initiator three times by the starvation feeding method, react for 2-3 hours, add 1 / 3 of the initiator, react for 1-2 hours, add 1 / 3 of the initiator, react for 1-2 hours, add the remaining initiator, and react for 0.5-1h; then add the end-capping agent, carry out the end-capping reaction for 1-2h, cool to 50-60°C, add the neutralizing agent, and neutralize for 0.5-1h; remove the reaction diluent by vacuum distillation to obtain a bio-based waterborne polyurethane waterproof finishing agent.

[0049] The beneficial effects of the present invention are:

[0050] The textiles treated with the bio-based waterborne polyurethane waterproof finishing agent of the present invention are soft to the touch and have good air permeability. Compared with the traditional polyurethane waterproof finishing agent, the textiles have bright colors and excellent migration resistance, and are environmentally friendly. The waterproof finishing agent can be used not only for waterproof finishing of textiles, but also for waterproof finishing of umbrellas, tents, car paints, walls and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The schematic diagram of the synthesis route of the present invention is shown in FIG. DETAILED DESCRIPTION

[0052] The present invention is further described below through specific examples, but the embodiments of the present invention are not limited thereto.

[0053] Test method:

[0054] (1) Particle size:

[0055] Take a small amount of sample and dilute it 1000 times with deionized water. Take an appropriate amount of the diluted sample into a particle size dish, and then put it into the Nano-Zs90 Zeta potential and particle size analyzer to measure the particle size and particle size distribution of the sample at 25°C. Measure three times and take the average value.

[0056] (2) Solid content

[0057] The solid content of the sample is determined by the weighing method: a small amount of sample is taken and dried in an oven to constant weight. The ratio of the sample mass after drying to the sample mass before drying is the solid content.

[0058] (3) Feel value:

[0059] Cut an area of ​​100cm on the fabric 2 The PhabrOmeter3 instrument is used to test the softness, resilience and flatness of the fabric.

[0060] (4) Color fastness:

[0061] The samples were tested for rubbing resistance in accordance with GB / T 29865-2013 “Textiles - Tests for Colour Fastness - Colour Fastness to Rubbing”, and for soaping test in accordance with Experiment Method C of GB / T 3921-2008 “Textiles - Tests for Colour Fastness - Colour Fastness to Washing with Soap”. The grey sample card was used to assess the colour fastness to rubbing and the colour fastness to washing with soap.

[0062] (5) Apparent color depth and levelness

[0063] Select 8 points randomly on the surface of the dyed fabric, use Datacolor 650 desktop spectrophotometer to measure the K / S value and ΔE (color difference value) of the dyed fabric, and take the average value.

[0064] (6) Waterproof

[0065] Refer to the method specified in GB / T 4744-2013. The temperature of the test water is 50℃. The water pressure is continuously increased on the sample at a water pressure rise rate of 6.0kPa / min. Observe whether the fabric seeps water and record the level.

[0066] (7)-Determination of NCO content:

[0067] The di-n-butylamine method was used to determine the content of isocyanate groups in the reaction system.

[0068] Accurately weigh 1.5g of sample and put it into a conical flask, add 10ml of anhydrous toluene, shake to dissolve, add 10ml of 1mol / L di-n-butylamine toluene solution with a pipette, shake well, let stand for 15 minutes, add 50ml of isopropanol and 3 drops of 0.1% bromocresol green indicator, and titrate with 0.5mol / L hydrochloric acid standard solution until the sample solution changes from blue to yellow, which is the end point;

[0069] The -NCO content can be calculated according to the following formula (1):

[0070]

[0071] Where V 0 is the volume of blank consumed HCl standard solution (L), V 1 is the volume of HCl standard solution consumed by the sample to be tested (L), C HCl is the concentration of hydrochloric acid standard solution (mol / L), and m is the sample mass (g).

[0072] Embodiment 1:

[0073] A method for preparing a bio-based waterborne polyurethane waterproof finishing agent comprises the following steps:

[0074] 4.24g of bio-based toluene diisocyanate and 10g of castor oil-based polyol (molecular weight of 2000, hydroxyl value of 322mg / g) were added to a four-necked flask equipped with a magnetic stirrer, a reflux condenser and a thermometer, and mechanically stirred at a speed of 500r / min. The mixture was heated to 70°C, and 0.04g of catalyst dibutyltin dilaurate was added, and the reaction was continued for 5h. The content of free -NCO in the system was titrated by the di-n-butylamine method. When the -NCO content reached the theoretical value, 0.2g of disperse blue 14 and 1.78g of bio-based chain extender 1,2-dihydroxy-3-propanesulfonic acid sodium were slowly added to the flask, and 10ml of acetone was added to reduce the viscosity of the system. The reaction was continued for 6h. The temperature was lowered to 60°C, and 0.58g of end-capping agent hydroxyethyl methacrylate was added. The semi-end-capping reaction was continued for 1h. The -NCO content of the system was titrated. When the -NCO content reaches the theoretical value, the temperature is raised to 75°C, 0.5g of hydrophobically modified monomer dodecafluoroheptyl methacrylate is added, and after uniform mixing, 0.2g of initiator ammonium persulfate is added three times by the starvation feeding method, and 1 / 3 of the initiator is added after reacting for 2h, and 1 / 3 of the initiator is added after reacting for 1.5h, and the remaining initiator is added after reacting for 1h, and the reaction is continued for 0.5h; 0.67g of trimethylolpropane is added, and the end-capping reaction is carried out for 1h; the temperature is lowered to 50°C, 1g of neutralizing agent triethylamine is added, and the neutralization reaction is carried out for 30min, 40g of deionized water is added, and the mixture is stirred at a speed of 2000r / min for 1h; the organic solvent is removed by vacuum distillation to obtain a bio-based waterborne polyurethane waterproof finishing agent; the obtained waterproof finishing agent has a particle size of 127.3nm, a PDI of 0.118, and a solid content of 30wt%.

[0075] Weigh 10 g of the bio-based waterborne polyurethane waterproof finishing agent prepared in this embodiment, 0.5 g of the thickener DM-5221G and 20 g of deionized water, control the slurry viscosity at 600 cps, and obtain a waterproof finishing color paste; use a coating machine to coat the fabric, control the coating thickness of the printed coating to 100 μm, dry at 60° C., and bake at 160° C. for 3 min to obtain a waterproof colored fabric.

[0076] Example 2

[0077] A method for preparing a bio-based waterborne polyurethane waterproof finishing agent comprises the following steps:

[0078] The same as Example 1, except that the castor oil-based polyol is adjusted to a wood fiber-based polyol (molecular weight of 2000, hydroxyl value of 422 mg / g), and other conditions remain unchanged.

[0079] Example 3

[0080] A method for preparing a bio-based waterborne polyurethane waterproof finishing agent comprises the following steps:

[0081] The same as Example 1, except that the castor oil-based polyol is adjusted to rapeseed oil-based polyol (molecular weight of 2000, hydroxyl value of 275 mg / g), and other conditions remain unchanged.

[0082] Example 4

[0083] A method for preparing a bio-based waterborne polyurethane waterproof finishing agent comprises the following steps:

[0084] The same as Example 1, except that the dodecafluoroheptyl methacrylate in Example 1 is adjusted to octadecyl methacrylate, and other conditions remain unchanged.

[0085] Example 5

[0086] The water-based polyurethane waterproof finishing agent prepared in Example 1 was weighed in an amount of 80% and the balance was deionized water, the slurry viscosity was controlled at 200 cps, a spray slurry was obtained, and the surface of the fabric was coated by spraying, with an interval of 30 cm, a spraying speed of 40 cm / s, and spraying in small amounts and multiple times, the coating thickness was controlled to be 200 μm, dried at 60° C., and baked at 160° C. for 3 min to obtain a waterproof colored fabric.

[0087] Example 6

[0088] Referring to Example 1, the coating thickness in Example 1 was adjusted to 200 μm, and other conditions remained unchanged.

[0089] Comparative Example 1

[0090] Referring to Example 1, the amount of Disperse Blue 14 in Example 1 was adjusted to 0 g, and the formula of the waterproof finishing color paste was adjusted to: 10 g of bio-based water-based polyurethane waterproof finishing agent, 0.5 g of thickener DM-5221G, 0.1 g of Disperse Blue 14 and 20 g of deionized water.

[0091] Comparative Example 2

[0092] Referring to Example 1, the waterproof finishing color paste in Example 1 was adjusted to 0.9g of commercially available waterproof finishing agent XSY-C308C, 10g of deionized water, 0.2g of thickener, 0.1g of disperse blue 14 and 0.1g of dispersant DM1501 were added. The fabric was coated with a coating machine, the coating thickness of the printed coating was controlled to be 100 μm, dried at 60°C, and baked at 160°C for 3 minutes to obtain a waterproof colored fabric.

[0093] Comparative Example 3

[0094] Referring to Example 1, the coating thickness in Example 1 was adjusted to 300 μm, and other conditions remained unchanged.

[0095] The performance test results of the waterproof colored fabrics obtained in Examples 1-6 and Comparative Examples 1-3 are shown in Table 1 below:

[0096] Table 1

[0097]

[0098] As can be seen from Table 1, the bio-based polyurethane waterproof finishing agent of the present invention can ensure a high air permeability retention rate while maintaining a high anti-static water pressure. Compared with the traditional post-finishing waterproof finishing agent, the present invention has the characteristics of higher color depth and smaller color difference, and has little effect on the color performance of the fabric; at the same time, the fastness and feel of the finished fabric can meet the production and daily use, and the raw materials of this product are all bio-based materials, which has great advantages in energy saving, emission reduction, and green environmental protection.

[0099] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing a bio-based waterborne polyurethane waterproof finishing agent, characterized in that: The preparation method comprises the following steps: (1) bio-based isocyanate and bio-based polyol react under the action of a catalyst, and after the reaction, a dye and a bio-based chain extender are added to continue the chain extension reaction, and after the reaction, a diluent and a blocking agent are added to carry out a semi-blocking reaction to obtain a semi-blocked isocyanate intermediate; (2) adding a hydrophobic modified monomer and an initiator to the reaction system of step (1), adding a capping agent to carry out a capping reaction after the polymerization reaction is completed, cooling the reaction after the reaction is completed, adding a neutralizing agent, and removing the diluent after the neutralization reaction is completed to obtain the bio-based waterborne polyurethane waterproof finishing agent; The solid content of the bio-based waterborne polyurethane waterproof finishing agent is 10-60wt%.

2. The preparation method according to claim 1, characterized in that: In step (1), the bio-based isocyanate is one or more of toluene diisocyanate, dimer acid diisocyanate, 1,5-pentane diisocyanate, and lysine diisocyanate; The bio-based polyol is one or more of epoxidized tung oil alcoholysate, rosin polyether polyol, castor oil-based polyol, rapeseed oil polyol, isosorbide-based polyester polyol, and wood fiber-based polyol; the average molecular weight of the bio-based polyol is 200-3000; The catalyst is one or more of stannous octoate, stannous oleate, dibutyltin dilaurate, triethylenediamine, dimethylethanolamine, N-methylmorpholine, and N,N-dimethylcyclohexylamine; The molar ratio of bio-based isocyanate to bio-based polyol is 2-6:1; The amount of the catalyst used is 0.05-0.2% of the total mass of the bio-based isocyanate and the bio-based polyol.

3. The preparation method according to claim 1, characterized in that: In step (1), the dye is a dye containing an amino group or a hydroxyl group in its structure; The bio-based chain extender is one or more of sodium 1,2-dihydroxy-3-propanesulfonate, aminosulfonate, sodium ethylenediaminesulfonate, sodium N,N-di(2-hydroxyethyl)-2-aminoethanesulfonate, and sodium 1,2-dihydroxy-3-propyl estersulfonate; The diluent is one or more of acetone, N,N-diformamide, and N-methylpyrrolidone; The end-capping agent is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, N,N-dimethylethanolamine, and trimethylolpropane; The molar ratio of bio-based isocyanate to dye is 5-30:1; The molar ratio of bio-based isocyanate to bio-based chain extender is 8-25:1; The amount of diluent used is 50-150% of the total mass of the reactants; The molar ratio of the blocking agent to the bio-based isocyanate is 1:3-10.

4. The preparation method according to claim 1, characterized in that: In step (1), the conditions for the reaction of bio-based isocyanate and bio-based polyol are: 70-100° C., reaction time 1-3 h; The conditions of the chain extension reaction are: 70-100°C, reaction time 2-6h; The conditions for the semi-blocking reaction are: 50-80°C for 1-2h.

5. The preparation method according to claim 1, characterized in that: In step (2), the hydrophobically modified monomer is one or more of hexafluorobutyl methacrylate, dodecafluoroheptyl methacrylate, octadecyl methacrylate, and vinyl-terminated polydimethylsiloxane; The initiator is one or more of ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride; The molar ratio of the hydrophobically modified monomer to the end-capping agent is 1-10:10; The amount of the initiator used is 1-3% of the total mass of the hydrophobically modified monomer and the end-capping agent.

6. The preparation method according to claim 1, characterized in that: In step (2), the end-capping agent is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, N,N-dimethylethanolamine, and trimethylolpropane; The neutralizing agent is one or more of triethylamine, ammonia water, hydrochloric acid, sodium hydroxide, and acetic acid; The molar ratio of the end-capping agent to the bio-based chain extender is 1:0.3-1.8; The molar ratio of the neutralizer to the bio-based chain extender is 0.5-1.5:

1.

7. The preparation method according to claim 1, characterized in that: In step (2), the polymerization reaction conditions are: 60-80° C., reaction time 6-8 h; The conditions for the end-capping reaction are: 60-80°C, reaction time 1-2h; The conditions for the neutralization reaction are: 50-60°C, reaction time 0.5-1h.

8. A bio-based waterborne polyurethane waterproof finishing agent prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the bio-based waterborne polyurethane waterproof finishing agent according to claim 8 in textile finishing.

10. The use according to claim 9, characterized in that: It is applied to textile fabrics by printing or spraying, with a thickness of 20-300μm.

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