Bio-based water-based anionic polyurethane sizing agent with ultraviolet resistance and high solid content as well as preparation method and application of bio-based water-based anionic polyurethane sizing agent

Abstract

The invention provides a bio-based waterborne anionic polyurethane sizing agent with ultraviolet resistance and high solid content as well as a preparation method and application thereof, and belongs to the technical field of sizing agents. The method comprises the following steps: mixing polyether glycol, diisocyanate, a hydrophilic chain extender, a catalyst and a solvent, then carrying out a reaction, carrying out an end-capping reaction on a prepolymer and an end-capping reagent so as to obtain a waterborne polyurethane emulsion, adding a neutralizer into the waterborne polyurethane emulsion, carrying out a neutralization reaction, and thus obtaining the waterborne polyurethane. And carrying out self-emulsifying reaction on the obtained polyurethane main slurry and water to obtain the bio-based waterborne anionic polyurethane sizing agent. The bio-based water-based anionic polyurethane sizing agent disclosed by the invention is beneficial to synchronously realizing better infiltration of carbon fibers and chemical bonding with PA6 resin, so that a carbon fiber composite material shows better mechanical properties and can stably exist in a long-term ultraviolet irradiation environment.

Description

Technical Field

[0001] This invention relates to the field of sizing agents, and more particularly to a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content, its preparation method, and its application. Background Technology

[0002] Carbon fiber, due to its superior properties such as high strength, high modulus, and low density, is widely used in aerospace, automotive, and sporting goods industries. However, in the preparation of composite materials, the interfacial bonding performance between carbon fiber and the matrix resin often determines the overall mechanical properties of the material. Nylon resin, as a commonly used thermoplastic matrix material, has good wear resistance and toughness, but its weak polarity leads to significant interfacial compatibility issues with the inert surface of carbon fiber. This insufficient interfacial bonding force makes it difficult to effectively transfer loads, and the composite material is prone to delamination, cracking, and other failure phenomena, thus limiting the engineering applications of carbon fiber / nylon composites.

[0003] Studies have found that sizing carbon fibers can effectively improve the mechanical properties of carbon fiber / nylon composites. Patent CN112359603B describes a method for preparing chain extenders grafted with nano-oxides, then reacting them with polyols and diisocyanates to synthesize hyperbranched polyurethane, which is then dispersed in an aqueous phase to obtain a sizing agent suitable for carbon fiber surface treatment. This imparts excellent UV resistance to the material and extends the service life of the composite. However, this method still has certain limitations in practical applications. For example, it involves numerous synthesis steps, including chain extender preparation, polyurethane prepolymer generation, and subsequent neutralization treatment, resulting in a long operation time. Furthermore, it requires organic solvents and metal catalysts, increasing the complexity and cost of the preparation process, which is not conducive to industrial application. Patent CN119241807A discloses a water-based polyurethane sizing agent, the main component of which is linear polyurethane. This agent is prone to yellowing and aging under long-term light exposure, which may limit its application.

[0004] Therefore, it is of great significance to provide a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content. Summary of the Invention

[0005] The purpose of this invention is to provide a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content, as well as its preparation method and application, in order to address the shortcomings of existing technologies.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content, comprising the following steps: 1) Polyether diol, diisocyanate, hydrophilic chain extender, catalyst and solvent are mixed and reacted to obtain a prepolymer; 2) The prepolymer and the end-capping agent undergo an end-capping reaction to obtain an aqueous polyurethane emulsion. A neutralizing agent is added to the aqueous polyurethane emulsion for a neutralization reaction to obtain the polyurethane main slurry. 3) The polyurethane main slurry and water undergo a self-emulsification reaction to obtain a bio-based waterborne anionic polyurethane sizing agent; Step 1) The hydrophilic chain extender contains hydroxy acid and cellulose, wherein the hydroxy acid is 2,2-dihydroxymethylbutyric acid or 2,2-dihydroxymethylpropionic acid, and the cellulose is hydroxyethyl cellulose or hydroxymethyl cellulose.

[0007] Preferably, the mass ratio of the polyether diol, diisocyanate, hydrophilic chain extender, catalyst and solvent in step 1) is 0.1~10:2~10:0.1~10:0.01~0.04:1~10.

[0008] Preferably, the polyether diol is polyethylene glycol or polypropylene glycol, and the molecular weight of the polyether diol is 200-2000; the diisocyanate is isoflavone diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate; the catalyst is dibutyltin dilaurate; and the solvent is acetone or N,N-dimethylformamide.

[0009] Preferably, the reaction temperature in step 1) is 75~85℃ and the reaction time is 2~5h; the end-capping reaction temperature in step 2) is 75~85℃ and the end-capping reaction time is 0.5~2h; the neutralization reaction temperature is 40~50℃ and the neutralization reaction time is 0.3~1h; the reaction in step 1) and the end-capping reaction in step 2) are carried out under a protective atmosphere.

[0010] Preferably, the mass ratio of the capping agent in step 2) to the polyether diol in step 1) is 0.1~10:0.1~10; the mass ratio of the waterborne polyurethane emulsion to the neutralizing agent in step 2) is 1~5:0.1~10.

[0011] Preferably, the capping agent in step 2) comprises one or more of caffeic acid, ferulic acid, curcumin and tannic acid, and the neutralizing agent is triethylamine.

[0012] Preferably, the mass ratio of the aqueous polyurethane emulsion in step 2) to the water in step 3) is 1~5:90~99; the self-emulsification reaction time in step 3) is 15~40 min, and the rotation speed is 200~500 r / min.

[0013] The present invention also provides a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content prepared by the above preparation method.

[0014] The present invention also provides the application of the aforementioned bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content in carbon fiber.

[0015] The beneficial effects of this invention are: 1) The main sizing agent of this invention is polyurethane, which is compatible with thermoplastic resins. The bio-based end-capped monomers in the sizing agent possess UV resistance properties, protecting the sizing agent from yellowing and imparting UV resistance to the composite material. By adjusting the ratio of anionic groups and soft segments, it achieves a high solids content. The sizing agent of this invention is not only storage stable but also effectively improves the interfacial bonding between carbon fiber and polyamide 6 (PA6), enhancing the mechanical properties of the CF / PA6 composite material and endowing it with excellent UV resistance. This bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content can be used in various fields, such as the preparation of materials for carbon paper and sports equipment.

[0016] 2) The polyurethane of the present invention has a polymer structure with anti-ultraviolet properties, which can protect the aromatic polyurethane from degradation and yellowing under ultraviolet light. It also has the characteristics of low viscosity and high density of oxygen-containing groups such as hydroxyl and carboxyl groups, which is conducive to simultaneously achieving better impregnation of carbon fibers and chemical bonding with PA6 resin, so that the carbon fiber composite material exhibits better mechanical properties and can exist stably under long-term ultraviolet light irradiation. Attached Figure Description

[0017] Figure 1 The structural formula of the polyurethane in the polyurethane main slurry of the present invention is shown below; Figure 2 SEM image of commercially available T300 carbon fiber after slurry removal; Figure 3 This is a SEM image of commercially available T300 carbon fiber after sizing with a water-based anionic polyurethane sizing agent with UV resistance, as described in Example 1. Figure 4 The image shows the infrared spectrum of the waterborne polyurethane emulsion in Example 1. Detailed Implementation

[0018] This invention provides a method for preparing a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content, comprising the following steps: 1) Polyether diol, diisocyanate, hydrophilic chain extender, catalyst and solvent are mixed and reacted to obtain a prepolymer; 2) The prepolymer and the end-capping agent undergo an end-capping reaction to obtain an aqueous polyurethane emulsion. A neutralizing agent is added to the aqueous polyurethane emulsion for a neutralization reaction to obtain the polyurethane main slurry. 3) The polyurethane main slurry and water undergo a self-emulsification reaction to obtain a bio-based waterborne anionic polyurethane sizing agent; Step 1) The hydrophilic chain extender contains hydroxy acid and cellulose, wherein the hydroxy acid is 2,2-dihydroxymethylbutyric acid or 2,2-dihydroxymethylpropionic acid, and the cellulose is hydroxyethyl cellulose or hydroxymethyl cellulose.

[0019] In this invention, the viscosity of hydroxyethyl cellulose is preferably 200~7000 mPa·s, more preferably 800~5000 mPa·s, and even more preferably 2000~4000 mPa·s; the viscosity of hydroxymethyl cellulose is preferably 100~10000 mPa·s, more preferably 1000~8000 mPa·s, and even more preferably 3000~6000 mPa·s.

[0020] In this invention, the polyether diol, hydrophilic chain extender, and end-capping agent described in step 1) are dried and then mixed. The drying temperature is preferably 110~130℃, more preferably 120℃, and the drying time is preferably 1.5~2.5h, more preferably 2h.

[0021] In this invention, the mass ratio of polyether diol, diisocyanate, hydrophilic chain extender, catalyst and solvent in step 1) is preferably 0.1~10:2~10:0.1~10:0.01~0.04:1~10, more preferably 1~8:3~7:1~8:0.02~0.03:3~8, and even more preferably 3~6:4~6:3~6:0.025:4~6.

[0022] In this invention, the polyether diol is preferably polyethylene glycol or polypropylene glycol, and the molecular weight of the polyether diol is preferably 200-2000, more preferably 500-1500, and even more preferably 800-1000; the diisocyanate is preferably isoflavone diisocyanate, toluene diisocyanate, or diphenylmethane diisocyanate; the catalyst is preferably dibutyltin dilaurate; and the solvent is preferably acetone or N,N-dimethylformamide.

[0023] In this invention, the reaction temperature in step 1) is preferably 75~85℃, more preferably 77~83℃, and even more preferably 80℃, and the reaction time is preferably 2~5h, and even more preferably 3~4h; the end-capping reaction temperature in step 2) is preferably 75~85℃, more preferably 77~83℃, and even more preferably 80℃, and the end-capping reaction time is preferably 0.5~2h, and even more preferably 1~1.5h; the neutralization reaction temperature is preferably 40~50℃, more preferably 42~48℃, and even more preferably 45~46℃, and the neutralization reaction time is preferably 0.3~1h, and even more preferably 0.5~0.75h; the reaction in step 1) and the end-capping reaction in step 2) are preferably carried out under a protective atmosphere.

[0024] In this invention, the mass ratio of the capping agent in step 2) to the polyether diol in step 1) is preferably 0.1~10:0.1~10, more preferably 2~8:2~8, and even more preferably 4~6:4~6; the mass ratio of the aqueous polyurethane emulsion to the neutralizing agent in step 2) is preferably 1~5:0.1~10, more preferably 2~4:2~8, and even more preferably 3:4~6.

[0025] In this invention, the capping agent in step 2) preferably includes one or more of caffeic acid, ferulic acid, curcumin and tannic acid, and the neutralizing agent is preferably triethylamine.

[0026] In this invention, after the neutralization reaction is completed, the solvent in the emulsion is removed by vacuum filtration to obtain the polyurethane main slurry.

[0027] In this invention, the mass ratio of the aqueous polyurethane emulsion in step 2) to the water in step 3) is preferably 1~5:90~99, more preferably 2~4:92~97, and even more preferably 3:94~95; the self-emulsification reaction time in step 3) is preferably 15~40 min, more preferably 20~35 min, and even more preferably 25~30 min; the rotation speed is preferably 200~500 r / min, more preferably 300~400 r / min, and even more preferably 350 r / min.

[0028] The present invention also provides a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content prepared by the above preparation method.

[0029] In this invention, the bio-based aqueous anionic polyurethane is a bio-based polyphenol-terminated aqueous polyurethane or a polyhydroxy bio-based alcohol-terminated aqueous polyurethane.

[0030] The present invention also provides the application of the aforementioned bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content in carbon fiber.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] In the embodiments, all raw materials used were commercially available; all parts of raw materials were by weight; the release agent was Weiling C-3 type release agent produced by Shanghai Xuling New Material Technology Co., Ltd. The release agent is used for demolding after hot pressing to prepare composite materials, so as to avoid the mold and composite material sticking together and failing to form.

[0033] Example 1

[0034] Polypropylene glycol-800, 2,2-dimethylolbutyric acid, hydroxymethyl cellulose (viscosity 800~1500 mPa·s), and curcumin were dried in an oven at 120℃ for 2 hours and then cooled for later use. Four parts of polypropylene glycol-800, 0.7 parts of 2,2-dimethylolbutyric acid, and 2 parts of isoflavone diisocyanate were added to a three-necked flask containing 8 parts of acetone. Under a nitrogen atmosphere, the temperature was raised to 75℃ at 180 r / min and maintained for 1 hour. Then, 0.5 parts of hydroxymethyl cellulose and 0.02 parts of dibutyltin dilaurate were added dropwise, and the reaction continued for another 2 hours to obtain a prepolymer. Three parts of curcumin were added to the prepolymer, and the mixture was end-capped at 75℃ under a nitrogen atmosphere for 1 hour. During this time, an appropriate amount of acetone was added to adjust the viscosity of the system and maintain its agitation capability, resulting in an aqueous polyurethane emulsion.

[0035] Two parts of aqueous polyurethane emulsion were cooled to 45°C, and 1.4 parts of triethylamine were added. The mixture was neutralized at 45°C for 0.5 h, and the solvent was removed by vacuum filtration to obtain the polyurethane main slurry. 98 parts of deionized water were added to the polyurethane main slurry, and the mixture was self-emulsified at 220 r / min for 20 min to obtain a curcumin-terminated aqueous anionic polyurethane sizing agent with UV resistance.

[0036] The curcumin-terminated waterborne anionic polyurethane sizing agent with UV protection properties in this embodiment was tested according to GB / T1725-2007 and had a solid content of 45.6%.

[0037] Example 2

[0038] Polypropylene glycol-800, 2,2-dimethylolbutyric acid, hydroxymethyl cellulose (viscosity 4000 mPa·s), and ferulic acid were dried in an oven at 120℃ for 2 hours and then cooled for later use. 2.5 parts of polypropylene glycol-800, 0.81 parts of 2,2-dimethylolbutyric acid, and 3.37 parts of isoflavone diisocyanate were added to a three-necked flask containing 7 parts of acetone. Under a nitrogen atmosphere, the temperature was raised to 75℃ at 180 rpm and maintained for 1 hour. Then, 0.5 parts of hydroxymethyl cellulose and 0.02 parts of dibutyltin dilaurate were added dropwise, and the reaction continued for another 2 hours to obtain a prepolymer. 3 parts of ferulic acid were added to the prepolymer, and the mixture was end-capped at 75℃ under a nitrogen atmosphere for 1 hour. During this time, an appropriate amount of acetone was added to adjust the viscosity of the system and maintain its agitation capability, resulting in an aqueous polyurethane emulsion.

[0039] Two parts of aqueous polyurethane emulsion were cooled to 42°C, and 1.6 parts of triethylamine were added. The mixture was neutralized at 42°C for 0.5 h, and the solvent was removed by vacuum filtration to obtain the polyurethane main slurry. 98 parts of deionized water were added to the polyurethane main slurry, and the mixture was self-emulsified at 270 r / min for 20 min to obtain a ferulic acid-terminated aqueous anionic polyurethane sizing agent with UV resistance.

[0040] The ferulic acid-terminated waterborne anionic polyurethane sizing agent with UV resistance in this embodiment was tested according to GB / T1725-2007 and has a solid content of 55%.

[0041] Example 3

[0042] Polyethylene glycol-500, 2,2-dimethylolpropionic acid, hydroxyethyl cellulose (viscosity 1500~2500 mPa·s), and caffeic acid were dried in an oven at 120℃ for 2 hours and then cooled for later use. Four parts of polyethylene glycol-500, 0.8 parts of 2,2-dimethylolpropionic acid, and 2.6 parts of toluene diisocyanate were added to a three-necked flask containing 6 parts of N,N-dimethylformamide. Under a nitrogen atmosphere, the temperature was raised to 85℃ at 180 r / min and maintained for 1.5 hours. Then, 0.5 parts of hydroxyethyl cellulose and 0.02 parts of dibutyltin dilaurate were added dropwise, and the reaction continued for 3 hours to obtain a prepolymer. Three parts of caffeic acid were added to the prepolymer, and the mixture was end-capped at 85℃ under a nitrogen atmosphere for 1 hour. During this time, an appropriate amount of N,N-dimethylformamide was added to adjust the viscosity of the system and maintain its agitation capability, resulting in an aqueous polyurethane emulsion.

[0043] Two parts of aqueous polyurethane emulsion were cooled to 48°C, and 1.6 parts of triethylamine were added. The mixture was neutralized at 48°C for 0.5 h, and the solvent was removed by vacuum filtration to obtain the polyurethane main slurry. 98 parts of deionized water were added to the polyurethane main slurry, and the mixture was self-emulsified at 240 r / min for 20 min to obtain a caffeic acid-terminated aqueous anionic polyurethane sizing agent with UV resistance.

[0044] The caffeic acid-terminated waterborne anionic polyurethane sizing agent with UV resistance in this embodiment was tested according to GB / T1725-2007 and had a solid content of 52%.

[0045] Example 4

[0046] Polyethylene glycol-200, 2,2-dimethylolpropionic acid, hydroxymethyl cellulose (viscosity 10000 mPa·s), and tannic acid were dried in an oven at 120℃ for 2 hours and then cooled for later use. Eight parts of polyethylene glycol-200, 0.8 parts of 2,2-dimethylolpropionic acid, and 2.6 parts of isoflavone diisocyanate were added to a three-necked flask containing 8 parts of acetone. Under a nitrogen atmosphere, the temperature was raised to 85℃ at 180 rpm and maintained for 1 hour. Then, 0.5 parts of hydroxymethyl cellulose and 0.02 parts of dibutyltin dilaurate were added dropwise, and the reaction continued for 3 hours to obtain a prepolymer. Eight parts of tannic acid were added to the prepolymer, and the mixture was end-capped at 85℃ under a nitrogen atmosphere for 1.5 hours. During this time, an appropriate amount of acetone was added to adjust the viscosity of the system and maintain its agitation capability, resulting in an aqueous polyurethane emulsion.

[0047] Two parts of aqueous polyurethane emulsion were cooled to 45°C, and 1.6 parts of triethylamine were added. The mixture was neutralized at 45°C for 0.5 h, and the solvent was removed by vacuum filtration to obtain the polyurethane main slurry. 98 parts of deionized water were added to the polyurethane main slurry, and the mixture was self-emulsified at 240 r / min for 20 min to obtain a tannic acid-terminated aqueous anionic polyurethane sizing agent with UV resistance.

[0048] The tannic acid-terminated waterborne anionic polyurethane sizing agent with UV resistance in this embodiment was tested according to GB / T1725-2007 and had a solid content of 42%.

[0049] The waterborne anionic polyurethane sizing agents with UV resistance prepared in Examples 1-4 were used to sizing desizing carbon fibers (T300). The carbon fibers were immersed in the waterborne anionic polyurethane sizing agents with UV resistance prepared in Examples 1-4 for 5 minutes, and then dried in an oven at 100°C for 1 hour. The microstructure of the carbon fiber surface before and after sizing was observed using electron microscopy. The SEM image of the desizing carbon fibers after sizing with the waterborne anionic polyurethane sizing agent with UV resistance prepared in Example 1 is shown below. Figure 3 As shown, by Figure 3 It can be seen that water-based anionic polyurethane sizing agent can be uniformly coated on the carbon fiber surface, and the surface grooves are basically eliminated, filling the defects on the carbon fiber surface, and the two have good bonding properties.

[0050] Application Example 1

[0051] Commercially available T-300 carbon fibers that have been completely desizing were impregnated in an aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 1 for 5 minutes. Then, they were hot-pressed with polyamide 6 at 250°C and 1.5 MPa for 30 minutes. After cooling to room temperature, a release agent was added and the mixture was removed to obtain the composite material.

[0052] Application Example 2

[0053] The aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 1 of Application Example 1 was replaced with the aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 2, and other process conditions were the same as in Application Example 1.

[0054] Application Example 3

[0055] The aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 1 of Application Example 1 was replaced with the aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 3, and other process conditions were the same as in Application Example 1.

[0056] Application Example 4

[0057] The aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 1 of Application Example 1 was replaced with the aqueous anionic polyurethane sizing agent with UV resistance prepared in Example 4, and other process conditions were the same as in Application Example 1.

[0058] Comparative Application Example 1

[0059] Commercially available T-300 carbon fiber that has been completely desizing was hot-pressed with polyamide 6 at 250°C and 1.5 MPa for 30 minutes. After cooling to room temperature, the composite material was obtained.

[0060] The composite materials corresponding to Examples 1-4 and Comparative Application Example 1 were subjected to bending tests and UV-aged bending tests. The prepared composite material sheets were cut into three-point bending test strips with dimensions of 80mm×13mm×2mm. The bending modulus and bending strength were obtained by testing with a universal testing machine. The results are shown in Table 1.

[0061] Table 1. Flexural modulus and flexural strength of composite materials in application examples and comparative application examples.

[0062] As shown in Table 1, the mechanical properties of the composite material prepared using the sizing agent of the present invention are significantly improved compared with the unsizing carbon fiber composite material.

[0063] After one week of UV aging with a xenon lamp, the composite materials of Application Examples 1-4 and Comparative Application Example 1 were tested for flexural modulus and flexural strength. The results are shown in Table 2.

[0064] Table 2. Flexural properties of composite materials after UV aging in application examples and comparative application examples.

[0065] After one week of UV aging with a xenon lamp, the composite materials of Application Examples 1-4 and Comparative Application Example 1 were tested for flexural modulus retention rate and flexural strength retention rate. The results are shown in Table 3.

[0066] Table 3. Flexural property retention rate of composite materials after UV aging in application examples and comparative application examples.

[0067] As shown in Tables 2 and 3, the composite material prepared using the sizing agent of the present invention has excellent UV resistance.

[0068] The method of this invention introduces a bio-based small molecule chain extender with an anti-UV structure, and then uses a water-soluble bio-based polyhydroxy polymer for end-capping to prepare an aqueous anionic polyurethane sizing agent with anti-UV properties. The sizing agent of this invention effectively improves the interfacial bonding ability of carbon fiber reinforced polyamide-based resin composites, solves the problem of easy yellowing and degradation failure of aromatic polyurethane sizing agents, and endows the composite material with excellent anti-UV properties.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content, characterized in that, It includes the following steps: 1) Polyether diol, diisocyanate, hydrophilic chain extender, catalyst and solvent are mixed and reacted to obtain a prepolymer; 2) The prepolymer and the end-capping agent undergo an end-capping reaction to obtain an aqueous polyurethane emulsion. A neutralizing agent is added to the aqueous polyurethane emulsion for a neutralization reaction to obtain the polyurethane main slurry. 3) The polyurethane main slurry and water undergo a self-emulsification reaction to obtain a bio-based waterborne anionic polyurethane sizing agent; Step 1) The hydrophilic chain extender contains hydroxy acid and cellulose, wherein the hydroxy acid is 2,2-dihydroxymethylbutyric acid or 2,2-dihydroxymethylpropionic acid, and the cellulose is hydroxyethyl cellulose or hydroxymethyl cellulose.

2. The preparation method according to claim 1, characterized in that, In step 1), the mass ratio of the polyether diol, diisocyanate, hydrophilic chain extender, catalyst, and solvent is 0.1~10:2~10:0.1~10:0.01~0.04:1~10.

3. The preparation method according to claim 1 or 2, characterized in that, The polyether diol is polyethylene glycol or polypropylene glycol, and the molecular weight of the polyether diol is 200-2000; the diisocyanate is isoflavone diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate; the catalyst is dibutyltin dilaurate; and the solvent is acetone or N,N-dimethylformamide.

4. The preparation method according to claim 3, characterized in that, The reaction temperature in step 1) is 75~85℃, and the reaction time is 2~5h; the end-capping reaction temperature in step 2) is 75~85℃, and the end-capping reaction time is 0.5~2h; the neutralization reaction temperature is 40~50℃, and the neutralization reaction time is 0.3~1h; the reaction in step 1) and the end-capping reaction in step 2) are carried out under a protective atmosphere.

5. The preparation method according to claim 4, characterized in that, The mass ratio of the capping agent in step 2) to the polyether diol in step 1) is 0.1~10:0.1~10; the mass ratio of the waterborne polyurethane emulsion to the neutralizing agent in step 2) is 1~5:0.1~10.

6. The preparation method according to claim 4 or 5, characterized in that, Step 2) The capping agent contains one or more of caffeic acid, ferulic acid, curcumin and tannic acid, and the neutralizing agent is triethylamine.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the aqueous polyurethane emulsion in step 2) to the water in step 3) is 1~5:90~99; the self-emulsification reaction time in step 3) is 15~40 min, and the rotation speed is 200~500 r / min.

8. A bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the bio-based waterborne anionic polyurethane sizing agent with UV resistance and high solids content as described in claim 8 in carbon fiber.

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