Aqueous sbs latex, its preparation method and application

Abstract

The present application relates to a kind of water-based SBS latex and its preparation method and application, the water-based SBS latex includes the dispersed phase portion of 5-55wt% of water-based SBS latex and the continuous phase portion of 45-95wt% formed by water.The water-based SBS latex of the present application can keep ideal mechanical stability, freeze-thaw stability and storage stability, avoid the possible emulsion separation of latex when environmental change greatly widen the adaptability of water-based SBS latex.The water-based SBS latex can be used in the field of asphalt modification, waterproof coating, adhesive.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to an aqueous SBS latex, its preparation method, and its application. Background Technology

[0002] SBS (styrene-butadiene-styrene block copolymer) is a triblock copolymer with styrene and butadiene as monomers. It combines the properties of both plastics and rubber, and is known as the "third-generation synthetic rubber." It possesses excellent tensile strength, a high coefficient of surface friction, good low-temperature performance, excellent electrical properties, and good processability, making it the most consumed thermoplastic elastomer. The SBS polymer chain is a combination of two block polymers with tandem plastic and elastic segments. Each intermediate polybutadiene segment (PB) is connected to a polystyrene segment (PS) at both ends. The soft segments (PB) and hard segments (PS) are incompatible. The hard polystyrene segments associate to form physical cross-linking points, which are chemically bonded to the soft polybutadiene segments in the middle. This phase-separated structure is called a microscopic two-phase separation structure. The polystyrene segments at both ends of the molecular chain aggregate to form nanoscale physical cross-linked regions, called microregions; while the polybutadiene segments form a soft, continuous phase, exhibiting high elasticity.

[0003] In recent years, water-based SBS latex has been widely used in areas such as emulsified asphalt modification, adhesives, waterproof coatings, and concrete modification due to its advantages such as being environmentally friendly, convenient to transport, simple to apply, and easy to use. It also avoids the high energy consumption required for heating operations. At the same time, its application performance is easy to adjust, which is conducive to the expansion of applications.

[0004] The preparation of waterborne SBS latex mainly involves external emulsification, which uses high-speed shearing to emulsify an SBS resin solution containing solvent or viscosity reducer in water under conditions of high surfactant presence. Examples include Zhang Qinqin's doctoral dissertation, "Study on the Influence of Emulsification of SBS Modified Asphalt on its Application Performance," and Luo Zhengbin's master's thesis, "Preparation of SBS Latex for Asphalt and its Application in Microsurfacing," including CN105237780B and CN106554470B. Due to its microscopic phase separation structure, SBS has poor self-emulsification and is difficult to disperse. Existing technologies prepare waterborne SBS latex by dissolving SBS in organic solvents such as toluene and cyclohexane to reduce resin viscosity, followed by dispersion and emulsification, and then solvent removal. While adding solvents makes SBS easier to disperse and emulsify in the presence of surfactants, the solvent removal process leads to increased collisions in the SBS latex due to increased temperature, and the high temperature also accelerates surfactant adsorption-desorption, resulting in easy sludge formation in the SBS latex and even demulsification during solvent removal. The presence of a large amount of surfactant in the system leads to rapid solvent evaporation during solvent removal, which can easily generate excessive foam, causing foam overflow or pipeline blockage. Slow solvent evaporation severely impacts production efficiency, and prolonged high-temperature shearing of SBS latex accelerates its instability. Furthermore, the addition of a large amount of surfactant may cause a decrease in water resistance when SBS latex is used in applications requiring high water resistance, such as building waterproofing. Storage stability of water-based SBS latex is also a major challenge in the industry. Because SBS has a lower density than water, it is prone to stratification during storage. As stratification worsens, the upper layers of SBS latex become increasingly compressed, and since surfactant adsorption is non-irreversible, this eventually leads to the formation of hard clumps that cannot be dispersed. Currently, the large particle size of water-based SBS latex and the weak stability of the surfactant result in poor freeze-thaw stability and mechanical stability, significantly limiting its applications. Waterborne SBS latex prepared using existing technologies often suffers from low solids content, instability, and easy demulsification. Poor stability has also been a persistent challenge in the industry, severely impacting the use of waterborne SBS latex. Summary of the Invention

[0005] Addressing the shortcomings of existing technologies and the strong hydrophobicity of SBS, this invention utilizes the high hydrophilicity of PVP to improve its hydrophilicity. Simultaneously, by modifying PVP with diisobutylene, the strong compatibility between diisobutylene and the butadiene segments in SBS is leveraged to stabilize the SBS latex and resolve the aforementioned issues. Furthermore, the modified PVP also has a thickening effect, further enhancing the stability of the SBS latex and preventing emulsion separation.

[0006] To achieve the above objectives, in a first aspect of the present invention, an aqueous SBS latex is provided, the aqueous SBS latex comprising a dispersed phase portion comprising 5-55 wt% of the total weight of the aqueous SBS latex and a continuous phase portion formed of water comprising 45-95 wt% of the total weight of the aqueous SBS latex.

[0007] Furthermore, the dispersed phase portion comprises an inner layer of SBS resin accounting for 89-98 wt% of the total weight of the dispersed phase, an outer layer of modified PVP accounting for 1-10 wt% of the total weight of the dispersed phase, and a solvent accounting for 0.1-1 wt% of the total weight of the dispersed phase.

[0008] In a second aspect of the present invention, a method for preparing an aqueous SBS latex is provided, comprising the following steps:

[0009] A. Prepare SBS adhesive solution and modified PVP aqueous solution separately;

[0010] B. The SBS adhesive solution was dispersed at high speed into a modified PVP aqueous solution to prepare an SBS suspension;

[0011] C. The SBS suspension is subjected to desolventizing treatment to obtain water-based SBS latex.

[0012] In a specific embodiment, a method for preparing an aqueous SBS latex includes the following steps:

[0013] a. Dissolve SBS resin in a solvent to prepare a 10-25 wt% SBS adhesive solution;

[0014] b. Mix the modified PVP with water and set aside;

[0015] c. At 50-70℃, the SBS adhesive solution is dispersed at high speed into the modified PVP aqueous solution to prepare an SBS suspension;

[0016] d. The prepared SBS suspension is vacuumed at 60-70℃ to remove solvent until the solvent content is less than 1wt% (based on the dispersed phase in the SBS latex) to obtain aqueous SBS latex.

[0017] Preferably, the solvent in step a can be selected from one or two of toluene and cyclohexane, more preferably cyclohexane;

[0018] Preferably, the dissolution temperature in step a is 50-70℃, the dissolution time is, for example, 1-2 hours, and the concentration of the dissolved SBS adhesive solution is 15-25 wt%, such as 18%, 20%, or 23%. If the concentration is too high, the viscosity of the SBS adhesive solution will be too high, which is not conducive to dispersion; if the concentration is too low, more solvent needs to be removed, which increases the solvent removal process and affects efficiency.

[0019] Preferably, the SBS resin mentioned in step a is selected from industrially produced SBS finished products, preferably one or more of the following: SBS resin from Baling Petrochemical Company, SBS resin from Asahi Kasei Corporation of Japan, SBS resin from Anic Company of Italy, SBS resin from Petrochim Company of Belgium, SBS resin from Kumho Corporation of South Korea, and SBS resin from KRATON Company of the United States; more preferably one or more of the following: YH-792, YH-791, YH-796, YH-188, YH-801, and Daogai-2# from Baling Petrochemical Company.

[0020] Preferably, the modified PVP in step b is diisobutylene-modified PVP, specifically obtained by copolymerization of diisobutylene and vinylpyrrolidone (NVP), with the molar percentage of diisobutylene in the modified PVP being 5-20%.

[0021] The modified PVP is prepared by mixing solvent and diisobutylene evenly in a reaction vessel, adding initiator and vinylpyrrolidone, reacting for a period of time, and then removing solvent to obtain modified PVP.

[0022] Specifically, in the preparation method of the modified PVP, the solvent is a solvent with a boiling point greater than 140℃, such as N-methylpyrrolidone, dimethylformamide, etc.; the initiator is di-tert-butyl peroxide;

[0023] Specifically, the reaction temperature is 90-130℃, the addition time of the initiator and vinylpyrrolidone is controlled to be 1-3h, and the reaction continues for 3-8h after the addition is completed.

[0024] Specifically, the molar ratio of diisobutylene to vinylpyrrolidone is 1:5 to 1:20, preferably 1:4 to 1:10;

[0025] Specifically, the initiator accounts for 0.1%-0.5% of the total mass of the monomers (diisobutylene and vinylpyrrolidone).

[0026] Specifically, the solvent removal operation is an existing technology, such as drying at 100-180℃ for 4-8 hours to remove the solvent to obtain modified PVP.

[0027] Preferably, modified PVP is dissolved in water to obtain modified PVP aqueous solutions of different concentrations.

[0028] Preferably, the concentration of the modified PVP aqueous solution in step b is 10-20 wt%, but this invention does not have any particular limitation.

[0029] Preferably, in step b, hydrochloric acid or acetic acid is used to control the pH to 2-5, and the prepared modified PVP aqueous solution is heated to 50-70℃ for later use.

[0030] The modified PVP can control the particle size of the SBS suspension containing solvent when dispersing it. The more modified PVP added, the smaller the particle size of the SBS suspension containing solvent under the same dispersion conditions. However, after a certain amount of modified PVP is added, the particle size of the suspension essentially stops changing. Sufficient amounts of modified PVP can also improve the stability of the emulsion and the stability of the subsequent product during solvent removal from the SBS suspension containing solvent. As a stabilizer, the modified PVP preferably accounts for 1-10 wt% of the total weight of the dispersed phase, more preferably 1-8 wt%, and even more preferably 1-5 wt%.

[0031] Preferably, in step c, the SBS adhesive is slowly added to the modified PVP aqueous solution under high-speed dispersion conditions, with a dispersion speed of 1000-3000 rpm, preferably 1500-2500 rpm; the high-speed dispersion time is 10-30 min, to prepare an SBS suspension containing solvent with a particle size of 0.5-25 μm.

[0032] Preferably, the particle size of the SBS suspension containing solvent obtained in step c is preferably controlled between 0.5-25 μm, more preferably between 1-20 μm. As the solvent evaporates in step d, the dispersed phase of the SBS suspension will shrink in volume during the solvent removal process. Therefore, the average particle size of the aqueous SBS latex finally obtained in step d is preferably between 2-15 μm.

[0033] Preferably, the vacuuming in step d is performed in a rotary evaporator, but can also be performed in a solvent removal vessel containing a stirrer. The temperature during vacuuming is preferably stable at 60-70°C. Solvent removal is preferably performed by slowly reducing the vacuum level at a stable temperature to prevent material overflow due to excessively low vacuum. Preferably, after a large amount of organic solvent has evaporated, the vacuum level is adjusted to -0.5 to -0.6 kPa, and vacuum distillation is carried out for approximately 1-3 hours to reduce the solvent content to below 1% (based on the dispersed phase portion), at which point vacuuming is stopped.

[0034] Preferably, the solid content (dispersed phase portion) of the final aqueous SBS latex accounts for 5-55 wt% of the total weight of the aqueous SBS latex, more preferably 20-50 wt%.

[0035] In a third aspect, the present invention provides the use of the above-mentioned waterborne SBS latex in the fields of asphalt modification, waterproof coatings, and adhesives.

[0036] Terminology Explanation:

[0037] The “average particle size” is the d50 value measured on the Helos / Sucell wet laser particle size analyzer (from Helos GmbH, Germany).

[0038] The particle size of the SBS suspension was statistically measured using a metallurgical microscope (SG-51) at the Shanghai Optical Instrument Factory.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The high hydrophilicity of PVP improves the hydrophilicity of SBS, thus preventing SBS from demulsifying and precipitating in the aqueous phase.

[0041] (2) By modifying PVP with diisobutylene, the strong compatibility between diisobutylene and butadiene segments in SBS can greatly improve the stability of SBS latex during devolatilization and greatly reduce the occurrence of demulsification.

[0042] (3) Diisobutylene-modified PVP also has a thickening effect, which further improves the storage stability of SBS latex and avoids emulsion separation. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to specific embodiments. However, the embodiments are not intended to limit the invention. Unless otherwise stated, all temperature and pressure units are standard temperature and pressure (STP). Optional addition indicates addition or omission.

[0044] Raw material source:

[0045] SBS resin: Baling Petrochemical Company, YH-791, YH-801, Daogai-2#;

[0046] NVP: Shandong Aite Chemical Co., Ltd.;

[0047] Diisobutylene: Hines;

[0048] Unless otherwise specified, all other ingredients are commercially available.

[0049] Emulsion performance testing:

[0050] 1. Storage stability test: Put about 0.5L of sample into a suitable plastic or glass container, leaving about 10% space inside the bottle. After sealing, put it in a constant temperature drying oven at (50±2)℃. After 2 weeks, take it out and place it at (23±2)℃ for 3 hours. Open the container and observe whether there is any layering, skin formation, hardening and flocculation.

[0051] 2. Freeze-thaw stability: Refer to GB / T 20623-2006. Put 50g of latex into a cylindrical plastic or glass container of about 100ml, taking care not to mix in air bubbles. After sealing, put it in a low temperature chamber at -5±2℃ for 18 hours. After that, take it out and place it at 23±2℃ for 6 hours. Repeat this process 3 times. After that, open the container, stir it with a glass rod, and then spread the latex on a glass plate to obtain a uniform thin layer. Observe whether there are any foreign objects such as flocculent matter.

[0052] 3. Mechanical stability: Weigh (400±0.5)g of the filtered emulsion (80 mesh) into a suitable container (approximately 100mm in diameter and 180mm in height) of approximately 1000mL. Place the emulsion on a high-speed disperser base and secure it with clamps. Start the disperser (with a disc-shaped stirring head approximately 40mm in diameter) and adjust the speed to 2500r / min. Disperse for 0.5h, then filter. Rinse the residue on the inner wall of the container into the filter with tap water. Rinse the filter with tap water and observe whether the emulsion has broken down and whether there are obvious flocculations.

[0053] 4. Latex solid content test: Refer to GB-T 2793-1995 for testing.

[0054] 5. Softening Point Test: SBS latex prepared in the examples and comparative examples was added to Qilu 70# emulsified matrix asphalt at a mass ratio of SBS in the SBS latex to asphalt in the emulsified matrix asphalt of 4:100, and thoroughly mixed to prepare modified emulsified asphalt. The softening point of the prepared modified emulsified asphalt was tested according to the national standard GB / T 4507-2014.

[0055] Example 1 of modified PVP preparation

[0056] (1) Add 100g of N-methylpyrrolidone and 40g of diisobutylene to a 1L reactor and stir until homogeneous. (2) Add 0.4g of di-tert-butyl peroxide and 360g of vinylpyrrolidone to a glass bottle and stir until homogeneous. (3) Heat the reactor to 100℃ and use a horizontal pump to add the mixture from (2) dropwise to the reactor over a period of 1 hour. Stir the mixture during the reaction and maintain the temperature at 100℃ for 4 hours. The reaction is then complete. (4) Place the modified PVP solution obtained from the reaction in a vacuum oven at 150℃ and dry for 8 hours to remove the solvent to obtain modified PVP-1.

[0057] Example 2 of modified PVP preparation

[0058] (1) Add 150g of dimethylformamide and 80g of diisobutylene to a 1L reactor and stir until homogeneous. (2) Add 0.9g of di-tert-butyl peroxide and 560g of vinylpyrrolidone to a glass bottle and stir until homogeneous. (3) Heat the reactor to 100℃ and use a horizontal pump to add the mixture from (2) dropwise to the reactor over a period of 2 hours. Stir the mixture during the reaction and maintain the temperature at 120℃ for 3 hours. The reaction is then complete. (4) Place the modified PVP solution obtained from the reaction in a vacuum oven at 150℃ and dry for 8 hours to remove the solvent to obtain modified PVP-2.

[0059] Example 1

[0060] In a 2L sealed reactor with reflux device, 200g of SBS resin (YH-791) and 600g of cyclohexane were mixed and heated to 60℃. The mixture was stirred at 200r / min for 60min to obtain an SBS solution containing solvent, which was then kept at this temperature for later use. In a 3L sealed dispersion vessel with reflux device, 66g of 10wt% modified PVP-1 aqueous solution was taken, and its pH was adjusted to 3 using acetic acid. The temperature was raised to 60℃, and the SBS solution containing solvent was added to the modified PVP aqueous solution through a heat-insulated pipeline while being dispersed at high speed at 2000rpm. The high-speed dispersion was continued for 20min. A sample was taken and observed under a metallographic microscope. The average particle size of the suspension was approximately 4.2µm before dispersion was stopped. The dispersed suspension was transferred to a rotary evaporator, heated to 65℃ and maintained at a constant temperature. Solvent removal was carried out by slowly reducing the vacuum. After a large amount of solvent evaporated, the vacuum was adjusted to -0.5kPa, and vacuum distillation was continued for approximately 2 hours before vacuum extraction was stopped. After cooling to below 45°C, the material is discharged and filtered to obtain water-based SBS latex with an average particle size of 2.7 μm and a solid content of 40.7 wt%.

[0061] Example 2

[0062] In a 2L sealed reactor with reflux device, 110g of SBS resin (YH-801) and 600g of cyclohexane were mixed and heated to 60℃. The mixture was stirred at 200r / min for 60min to obtain an SBS solution containing solvent, which was then kept warm for later use. In a 3L sealed dispersion vessel with reflux device, 25g of 10wt% modified PVP-1 aqueous solution was taken, and its pH was adjusted to 3 using acetic acid. The temperature was raised to 60℃, and the SBS solution containing solvent was added to the modified PVP aqueous solution through a heated pipeline at a high speed of 2000rpm. The high-speed dispersion was carried out for 20min. A sample was taken and observed under a metallographic microscope. The average particle size of the suspension was approximately 10µm before dispersion was stopped. The dispersed suspension was transferred to a rotary evaporator, heated to 65℃ and maintained at a constant temperature. Solvent removal was carried out by slowly reducing the vacuum. After a large amount of solvent evaporated, the vacuum was adjusted to -0.5kPa, and vacuum distillation was continued for approximately 2h before vacuuming was stopped. After cooling to below 45°C, the material is discharged and filtered to obtain water-based SBS latex with an average particle size of 5.6 μm and a solid content of 29.2 wt%.

[0063] Example 3

[0064] In a 2L sealed reactor with reflux device, 200g of SBS resin (Daugai-2#) and 600g of cyclohexane were mixed and heated to 60℃. The mixture was stirred at 200r / min for 60min to obtain an SBS solution containing solvent, which was then kept warm for later use. In a 3L sealed dispersion vessel with reflux device, 40g of a 10wt% modified PVP-2 aqueous solution was taken, and its pH was adjusted to 3 using acetic acid. The temperature was raised to 60℃, and the SBS solution containing solvent was added to the modified PVP aqueous solution through a heated pipeline at a high speed of 2000rpm. The high-speed dispersion was carried out for 20min. A sample was taken and observed under a metallographic microscope. The average particle size of the suspension was approximately 13µm before dispersion was stopped. The dispersed suspension was transferred to a rotary evaporator, heated to 65℃ and maintained at a constant temperature. Solvent removal was carried out by slowly reducing the vacuum. After a large amount of solvent evaporated, the vacuum was adjusted to -0.5kPa, and vacuum distillation was continued for approximately 2h before vacuuming was stopped. After cooling to below 45°C, the material is discharged and filtered to obtain an aqueous SBS latex with an average particle size of 11.4 μm and a solid content of 41.3 wt%.

[0065] Example 4

[0066] In a 2L sealed reactor with reflux device, 200g of SBS resin (YH-188) and 600g of cyclohexane were mixed and heated to 60℃. The mixture was stirred at 200r / min for 60min to obtain an SBS solution containing solvent, which was then kept at this temperature for later use. In a 3L sealed dispersion vessel with reflux device, 20g of 10%wt modified PVP-2 aqueous solution was taken, and its pH was adjusted to 3 using acetic acid. The temperature was raised to 60℃, and the SBS solution containing solvent was added to the modified PVP aqueous solution through a heat-insulated pipeline while being dispersed at high speed at 2000rpm. The high-speed dispersion was continued for 20min. A sample was taken and observed under a metallographic microscope. The average particle size of the suspension was approximately 16µm before dispersion was stopped. The dispersed suspension was transferred to a rotary evaporator, heated to 65℃ and maintained at a constant temperature. Solvent removal was carried out by slowly reducing the vacuum. After a large amount of solvent evaporated, the vacuum was adjusted to -0.5kPa, and vacuum distillation was continued for approximately 2 hours before vacuum extraction was stopped. After cooling to below 45°C, the material is discharged and filtered to obtain an aqueous SBS latex with an average particle size of 14.1 μm and a solid content of 42.2% by weight.

[0067] Comparative Example 1

[0068] Example 3 in CN105237780B

[0069] Comparative Example 2

[0070] Example 1 in CN106554470B

[0071] Comparative Example 3

[0072] In a 2L sealed reactor with reflux device, 200g of SBS resin (YH-188) and 600g of cyclohexane were mixed and heated to 60℃. The mixture was stirred at 200r / min for 60min to obtain an SBS solution containing solvent, which was then kept at this temperature for later use. In a 3L sealed dispersion vessel with reflux device, 2g of OP-10 emulsifier was added to 300g of deionized water. The pH was adjusted to 3 using acetic acid, and the temperature was raised to 60℃. The SBS solution containing solvent was then added to the aqueous solution containing OP-10 emulsifier through a heat-insulated pipeline at a high-speed dispersion of 2000rpm. The mixture was dispersed at high speed for 20min. A sample was taken and observed under a metallographic microscope. The average particle size of the suspension was approximately 16µm before dispersion was stopped. The well-dispersed suspension was transferred to a rotary evaporator, heated to 65°C and maintained at a constant temperature. Solvent removal was carried out by slowly reducing the vacuum. After a large amount of solvent evaporated, the vacuum was adjusted to -0.5 kPa, and vacuum distillation continued for about 2 hours. Vacuuming was then stopped. The mixture was cooled to below 45°C, discharged, and filtered to obtain an aqueous SBS latex with an average particle size of 14.5 μm and a solid content of 43% by weight.

[0073] The performance test results of the waterborne SBS latex prepared in each embodiment and comparative example are shown in Table 1.

[0074] Table 1. Performance test results of waterborne SBS latex

[0075]

[0076]

[0077] The waterborne SBS latex prepared by the process described in this invention, by adding modified PVP, can maintain ideal mechanical stability, freeze-thaw stability and storage stability without lowering the emulsification point of the modified emulsified asphalt, greatly expanding the adaptability of waterborne SBS latex.

Claims

1. A water-based SBS latex, characterized in that, The aqueous SBS latex comprises a dispersed phase portion of 5-55 wt% and a continuous phase portion of 45-95 wt% formed of water. The dispersed phase comprises an inner layer of SBS resin accounting for 89-98 wt% of the total weight of the dispersed phase, an outer layer of modified PVP accounting for 1-10 wt% of the total weight of the dispersed phase, and a residual solvent after solvent removal accounting for 0.1-1 wt% of the total weight of the dispersed phase; the modified PVP is diisobutylene-modified PVP, obtained by copolymerization of diisobutylene and vinylpyrrolidone, and the molar percentage of diisobutylene in the modified PVP is 5-20%.

2. The water-based SBS latex as described in claim 1, characterized in that, The modified PVP is prepared by mixing solvent and diisobutylene evenly in a reaction vessel, adding initiator and vinylpyrrolidone, reacting for a period of time, and then removing solvent to obtain modified PVP.

3. The water-based SBS latex as described in claim 2, characterized in that, In the preparation method of the modified PVP: The solvent is N-methylpyrrolidone or dimethylformamide; And / or: The initiator is di-tert-butyl peroxide; And / or: the molar ratio of diisobutylene to vinylpyrrolidone is 1:4 to 1:

19.

4. The water-based SBS latex as described in claim 3, characterized in that, In the preparation method of the modified PVP, the amount of initiator is 0.1%-0.5% of the total mass of diisobutylene and vinylpyrrolidone.

5. The water-based SBS latex as described in claim 3, characterized in that, In the preparation method of the modified PVP: the reaction temperature is 90-130℃, the addition time of the initiator and vinylpyrrolidone is controlled to be 1-3h, and the reaction continues for 3-8h after the addition is completed.

6. The water-based SBS latex as described in claim 1, characterized in that, The solvent is one or both of toluene and cyclohexane; And / or: The SBS is selected from one or more of YH-792, YH-791, YH-796, YH-188, YH-801, and Daogai-2#.

7. The water-based SBS latex as described in claim 1, characterized in that, The average particle size of the waterborne SBS latex is 0.5-25 μm.

8. The water-based SBS latex as described in claim 7, characterized in that, The average particle size of the water-based SBS latex is 1-20 μm.

9. A method for preparing the water-based SBS latex according to any one of claims 1-8, characterized in that, The method includes the following steps: a. Prepare SBS adhesive solution and modified PVP aqueous solution separately; b. SBS adhesive solution is dispersed at high speed into modified PVP aqueous solution to prepare SBS suspension; c. The SBS suspension is desolventized to obtain aqueous SBS latex.

10. The preparation method according to claim 9, characterized in that, In step a, the concentration of SBS adhesive solution is 15-25 wt%, and the concentration of modified PVP aqueous solution is 10-20 wt%.

11. The preparation method according to claim 9, characterized in that, In step b, the high-speed dispersion speed is 1000-3000 rpm, the high-speed dispersion time is 10-30 min, and the dispersion temperature is 50-70℃.

12. The preparation method according to claim 11, characterized in that, In step b, the high-speed dispersion speed is 1500-2500 rpm.

13. The preparation method according to claim 9, characterized in that, In step c, the solvent removal is performed using a vacuum method.

14. Use of the waterborne SBS latex according to any one of claims 1-8 or the waterborne SBS latex prepared by the preparation method according to any one of claims 9-13 in the fields of asphalt modification, waterproof coatings, and adhesives.

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