A polyvinyl alcohol fiber composite modified sulfur-based adhesive and its preparation method

Abstract

This invention relates to the field of adhesive technology, specifically to a polyvinyl alcohol fiber composite modified sulfur-based adhesive and its preparation method. The preparation method includes: S1. Mixing aggregates and mineral fillers evenly and preheating to 130-140℃ to obtain a preliminary mixture; S2. Adding modified sulfur and fiber modifier to the preliminary mixture, stirring at 130-140℃ for 10-15 minutes to obtain a secondary mixture; S3. Pouring the secondary mixture into a preheated mold, holding at 130-140℃ for 10-15 minutes, and cooling and demolding to obtain the polyvinyl alcohol fiber composite modified sulfur-based adhesive. This invention, through the formation of a stable sulfur chain structure by modifying sulfur, significantly reduces the brittleness of sulfur crystals. It also works synergistically with resin and fiber modifiers to further block media penetration, improve the adhesive's durability, overall flexibility, and impact resistance, and is perfectly matched with a dedicated constant-temperature construction device, achieving full-process control from preparation to molding.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a polyvinyl alcohol fiber composite modified sulfur-based adhesive and its preparation method. Background Technology

[0002] Polyvinyl alcohol fiber-modified sulfur-based adhesive is a novel thermoplastic cold-setting composite material made from polyvinyl alcohol fibers, dicyclopentadiene-modified sulfur, mineral fillers, and aggregates. This material features short setting time, high early strength, excellent crack resistance, strong chemical corrosion resistance, and recyclability. Unlike traditional cement-based adhesives, its core binding component is dicyclopentadiene-modified sulfur, requiring no water or cement addition during preparation and no special curing. Based on this characteristic, the material can be demolded after only a few hours of standing at room temperature following casting, and its compressive strength at one day is almost at its final strength. Therefore, this material shows broad application prospects in areas such as rapid road repair, chemically resistant structures, and in-situ space construction.

[0003] While polyvinyl alcohol fiber-modified sulfur-based adhesives offer excellent performance, their application is limited by existing traditional equipment, hindering the full realization of their properties. Unmodified sulfur is brittle, has a high shrinkage rate, and exhibits weak interfacial bonding with fibers and aggregates, easily leading to cracking and insufficient strength. Simply adding polyvinyl alcohol fibers and sulfur cannot achieve the ideal balance between early strength and long-term durability. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a polyvinyl alcohol fiber composite modified sulfur-based adhesive and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing a polyvinyl alcohol fiber composite modified sulfur-based adhesive includes the following preparation steps:

[0007] S1. By weight, mix 62-66 parts of aggregate and 4-8 parts of mineral filler evenly and preheat to 130-140℃ to obtain a preliminary mixture;

[0008] S2. Add 30-35 parts of modified sulfur and 2-5 parts of fiber modifier to the preliminary mixture obtained in step S1, maintain the temperature at 130-140℃, and stir at a speed of 200-300r / min for 10-15min to obtain the secondary mixture.

[0009] S3. Pour the mixture obtained in step S2 into a preheated mold, keep it at 130-140℃ for 10-15 minutes, and after cooling and demolding, obtain polyvinyl alcohol fiber composite modified sulfur-based adhesive.

[0010] The preparation of modified sulfur includes the following steps:

[0011] S11. By mass, heat 28-32 parts of sulfur to a molten state and add 0.8-1 parts of dicyclopentadiene, and stir at 200-250 r / min for 10-15 min at 130-140℃.

[0012] S12. Add 4-6 parts of resin modifier, 0.3-0.7 parts of γ-aminopropyltriethoxysilane and 0.8-1.2 parts of nano-silica to the product obtained in step S11, and continue stirring at 250-300 r / min for 10-15 min at 130-140℃ to obtain modified sulfur.

[0013] Preferably, the preparation of the fiber modifier includes the following steps:

[0014] S21. Dissolve 0.3-0.4 parts of dopamine hydrochloride in 26-30 parts of Tris-HCl buffer by weight, add 3-4 parts of polyvinyl alcohol fiber, shake and react at 35-40℃ for 10-12h, wash with deionized water until the water is clear, and dry at 60℃ to obtain PDA modified fiber.

[0015] S22. Disperse 0.4-0.6 parts of nano-silica ultrasonically in 8-12 parts of anhydrous ethanol, add 0.4-0.6 parts of KH-560 and 0.2-0.4 parts of isopropyltris(dioctylpyrophosphate)titanate and continue ultrasonic dispersion for 10-15 min to obtain a dispersion.

[0016] S23. Add the PDA-modified fiber obtained in step S21 to the dispersion obtained in step S22, stir at 200-250 r / min at 50℃ for 1-2 h, filter to remove the fiber, wash with ethanol 2-3 times, and vacuum dry at 70℃ for 3-4 h to obtain the fiber modifier.

[0017] Preferably, the preparation of the resin modifier includes the following steps:

[0018] S121. By weight, heat 2-4 parts of epoxy resin E-51 and 0.8-1.2 parts of polyurethane prepolymer to 75-80℃ and stir at 200-300 r / min for 15-20 min.

[0019] S122. While maintaining the temperature, add 1.6-2 parts of methylhexahydrophthalic anhydride, 0.05-0.07 parts of 2,4,6-tris(dimethylaminomethyl)phenol, 0.3-0.5 parts of KH-560 and 0.08-0.12 parts of antioxidant 1010 to the mixture obtained in step S121 and stir for 20-25 minutes.

[0020] S123. Cool the product after mixing in step S122 to 60°C, slowly add 1-3 parts of styrene-butadiene rubber latex, stir at a speed of 350-400 r / min for 15-20 min to avoid local demulsification, and degas under a vacuum of -0.095 MPa for 10-15 min to obtain the resin modifier.

[0021] Preferably, the mineral filler is selected from one or more of fly ash, silica fume, coal gangue powder, waste glass powder, sludge ash, metallurgical dust, slag powder, rice husk ash, and straw ash.

[0022] Preferably, the aggregate is selected from one or more of the following: river sand, quartz sand, manufactured sand, lake sand, tailings sand, recycled fine aggregate, and aeolian sand.

[0023] Preferably, the preheating temperature in step S3 is 130-140℃.

[0024] Preferably, the oscillation reaction speed in step S21 is 80-100 r / min.

[0025] Preferably, the frequency of ultrasonic dispersion in step S22 is 40 kHz.

[0026] Preferably, the stirring speed in step S122 is 350-400 r / min.

[0027] A polyvinyl alcohol fiber composite modified sulfur-based adhesive is prepared by the above preparation method.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] This invention modifies sulfur to form a stable sulfur chain structure, significantly reducing the brittleness of sulfur crystals. It also works synergistically with resin modifiers and fiber modifiers to further block media penetration, improve the durability, overall flexibility, and impact resistance of the adhesive, and is perfectly matched with a dedicated constant temperature construction device, achieving full process control from preparation to molding. Attached Figure Description

[0030] Figure 1 This is a process flow diagram for preparing the polyvinyl alcohol fiber composite modified sulfur-based adhesive of the present invention;

[0031] Figure 2 This is a flow chart of the preparation process of the modified sulfur of this invention;

[0032] Figure 3 This is a flow chart of the preparation process of the fiber modifier of the present invention;

[0033] Figure 4 This is a flow chart of the preparation process of the resin modifier of the present invention. Detailed Implementation

[0034] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] Please see Figure 1-4 The present invention provides a technical solution:

[0036] Example 1

[0037] A method for preparing a polyvinyl alcohol fiber composite modified sulfur-based adhesive:

[0038] Before preparing the polyvinyl alcohol fiber composite modified sulfur-based adhesive, the resin modifier, modified sulfur, and fiber modifier are prepared first:

[0039] The preparation of resin modifiers includes the following steps:

[0040] S121. Heat 2g of epoxy resin E-51 and 0.8g of polyurethane prepolymer (PUP) to 75°C and stir at 200r / min for 15min.

[0041] S122. While maintaining the temperature, add 1.6g of methylhexahydrophthalic anhydride, 0.05g of 2,4,6-tris(dimethylaminomethyl)phenol, 0.3g of KH-560 and 0.08g of antioxidant 1010 to the mixture obtained in step S121, and stir at 350r / min for 20min.

[0042] S123. Cool the product after mixing in step S122 to 60°C, slowly add 1g of styrene-butadiene rubber latex, stir at 350r / min for 15min to avoid local demulsification, and degas under vacuum of -0.095MPa for 10min to obtain the resin modifier.

[0043] The preparation of modified sulfur includes the following steps:

[0044] S11. Heat 28g of sulfur to a molten state and add 0.8g of dicyclopentadiene. Stir at 200r / min for 10min at 130℃.

[0045] S12. Add 4g of resin modifier, 0.3g of γ-aminopropyltriethoxysilane and 0.8g of nano-silica to the product obtained in step S11, and continue stirring at 250r / min for 10min at 130℃ to obtain modified sulfur.

[0046] The preparation of fiber modifiers includes the following steps:

[0047] S21. Dissolve 0.3g of dopamine hydrochloride in 26g of Tris-HCl buffer, add 3g of polyvinyl alcohol fiber, and react with shaking at 80r / min at 35℃ for 10h. Wash with deionized water until the water is clear, and dry at 60℃ to obtain PDA modified fiber.

[0048] S22. Disperse 0.4g of nano-silica in 8g of anhydrous ethanol at a frequency of 40kHz, add 0.4g of KH-560 and 0.2g of isopropyltris(dioctylpyrophosphoryloxy)titanate and continue ultrasonic dispersion for 10min to obtain a dispersion.

[0049] S23. Add the PDA-modified fiber obtained in step S21 to the dispersion obtained in step S22, stir at 200 r / min for 1 h at 50 °C, filter to remove the fiber, wash twice with ethanol, and vacuum dry at 70 °C for 3 h to obtain the fiber modifier.

[0050] S1. Mix 62g of river sand and 4g of fly ash evenly and preheat to 130℃ to obtain a preliminary mixture;

[0051] S2. Add 30g of modified sulfur and 2g of fiber modifier to the preliminary mixture obtained in step S1, maintain the temperature at 130℃, and stir at a speed of 200r / min for 10min to obtain the secondary mixture;

[0052] S3. Pour the secondary mixture obtained in step S2 into a preheated (130°C) mold, keep it at 130°C for 10 minutes, and after cooling and demolding, obtain polyvinyl alcohol fiber composite modified sulfur-based adhesive.

[0053] Example 2

[0054] A method for preparing a polyvinyl alcohol fiber composite modified sulfur-based adhesive:

[0055] Before preparing the polyvinyl alcohol fiber composite modified sulfur-based adhesive, the resin modifier, modified sulfur, and fiber modifier are prepared first:

[0056] The preparation of resin modifiers includes the following steps:

[0057] S121. Heat 4g of epoxy resin E-51 and 1.2g of polyurethane prepolymer (PUP) to 80°C and stir at 300r / min for 20min.

[0058] S122. While maintaining the temperature, add 2g of methylhexahydrophthalic anhydride, 0.07g of 2,4,6-tris(dimethylaminomethyl)phenol, 0.5g of KH-560 and 0.12g of antioxidant 1010 to the mixture obtained in step S121, and stir at 400r / min for 25min.

[0059] S123. Cool the product after mixing in step S122 to 60°C, slowly add 3g of styrene-butadiene rubber latex, stir at 400r / min for 20min to avoid local demulsification, and degas under vacuum of -0.095MPa for 15min to obtain the resin modifier.

[0060] The preparation of modified sulfur includes the following steps:

[0061] S11. Heat 32g of sulfur to a molten state and add 1g of dicyclopentadiene. Stir at 250r / min for 15min at 140℃.

[0062] S12. Add 6g of resin modifier, 0.7g of γ-aminopropyltriethoxysilane and 1.2g of nano-silica to the product obtained in step S11, and continue stirring at 300r / min for 15min at 140℃ to obtain modified sulfur.

[0063] The preparation of fiber modifiers includes the following steps:

[0064] S21. Dissolve 0.4g of dopamine hydrochloride in 30g of Tris-HCl buffer, add 4g of polyvinyl alcohol fiber, and shake at 100r / min at 40℃ for 12h. Wash with deionized water until the water is clear, and dry at 60℃ to obtain PDA modified fiber.

[0065] S22. Disperse 0.8g of nano-silica in 12g of anhydrous ethanol at a frequency of 40kHz, add 0.6g of KH-560 and 0.4g of isopropyl tris(dioctyl pyrophosphate) titanate and continue ultrasonic dispersion for 15min to obtain a dispersion.

[0066] S23. Add the PDA-modified fiber obtained in step S21 to the dispersion obtained in step S22, stir at 250 r / min for 2 h at 50 °C, filter to remove the fiber, wash three times with ethanol, and vacuum dry at 70 °C for 4 h to obtain the fiber modifier.

[0067] S1. Mix 66g of river sand and 8g of silica fume evenly and preheat to 140℃ to obtain a preliminary mixture;

[0068] S2. Add 35g of modified sulfur and 5g of fiber modifier to the preliminary mixture obtained in step S1, maintain the temperature at 140℃, and stir at a speed of 300r / min for 15min to obtain the secondary mixture.

[0069] S3. Pour the secondary mixture obtained in step S2 into a preheated (140°C) mold, keep it at 140°C for 15 minutes, and after cooling and demolding, obtain polyvinyl alcohol fiber composite modified sulfur-based adhesive.

[0070] Example 3

[0071] A method for preparing a polyvinyl alcohol fiber composite modified sulfur-based adhesive:

[0072] Before preparing the polyvinyl alcohol fiber composite modified sulfur-based adhesive, the resin modifier, modified sulfur, and fiber modifier are prepared first:

[0073] The preparation of resin modifiers includes the following steps:

[0074] S121. Heat 2.5g of epoxy resin E-51 and 0.9g of polyurethane prepolymer (PUP) to 76°C and stir at 220r / min for 16min.

[0075] S122. While maintaining the temperature, add 1.7g of methylhexahydrophthalic anhydride, 0.055g of 2,4,6-tris(dimethylaminomethyl)phenol, 0.35g of KH-560 and 0.09g of antioxidant 1010 to the mixture obtained in step S121, and stir at 360r / min for 21min.

[0076] S123. Cool the product after mixing in step S122 to 60°C, slowly add 1.5g of styrene-butadiene rubber latex, stir at 360r / min for 16min to avoid local demulsification, and degas under vacuum of -0.095MPa for 11min to obtain the resin modifier.

[0077] The preparation of modified sulfur includes the following steps:

[0078] S11. Heat 29g of sulfur to a molten state and add 0.85g of dicyclopentadiene. Stir at 220r / min for 11min at 132℃.

[0079] S12. Add 4.5g of resin modifier, 0.4g of γ-aminopropyltriethoxysilane and 0.9g of nano-silica to the product obtained in step S11, and continue stirring at 260r / min for 11min at 132℃ to obtain modified sulfur.

[0080] The preparation of fiber modifiers includes the following steps:

[0081] S21. Dissolve 0.32g of dopamine hydrochloride in 27g of Tris-HCl buffer, add 3.2g of polyvinyl alcohol fiber, and react with shaking at 85r / min at 36℃ for 10.5h. Wash with deionized water until the water is clear, and dry at 60℃ to obtain PDA modified fiber.

[0082] S22. Disperse 0.5g of nano-silica in 9g of anhydrous ethanol at a frequency of 40kHz, add 0.5g of KH-560 and 0.3g of isopropyl tris(dioctyl pyrophosphate) titanate and continue ultrasonic dispersion for 11min to obtain a dispersion.

[0083] S23. Add the PDA-modified fiber obtained in step S21 to the dispersion obtained in step S22, stir at 220 r / min at 50℃ for 1.5 h, filter to remove the fiber, wash twice with ethanol, and vacuum dry at 70℃ for 3.5 h to obtain the fiber modifier.

[0084] S1. Mix 63g of manufactured sand and 5g of coal gangue powder evenly and preheat to 132℃ to obtain a preliminary mixture;

[0085] S2. Add 31g of modified sulfur and 3g of fiber modifier to the preliminary mixture obtained in step S1, maintain the temperature at 132℃, and stir at a speed of 220r / min for 11min to obtain the secondary mixture;

[0086] S3. Pour the secondary mixture obtained in step S2 into a preheated (132°C) mold, keep it at 132°C for 11 minutes, and after cooling and demolding, obtain polyvinyl alcohol fiber composite modified sulfur-based adhesive.

[0087] Example 4

[0088] A method for preparing a polyvinyl alcohol fiber composite modified sulfur-based adhesive:

[0089] Before preparing the polyvinyl alcohol fiber composite modified sulfur-based adhesive, the resin modifier, modified sulfur, and fiber modifier are prepared first:

[0090] The preparation of resin modifiers includes the following steps:

[0091] S121. Heat 3g of epoxy resin E-51 and 1.1g of polyurethane prepolymer (PUP) to 78°C and stir at 280r / min for 18min.

[0092] S122. While maintaining the temperature, add 1.9g of methylhexahydrophthalic anhydride, 0.06g of 2,4,6-tris(dimethylaminomethyl)phenol, 0.45g of KH-560 and 0.11g of antioxidant 1010 to the mixture obtained in step S121, and stir at 380r / min for 24min.

[0093] S123. Cool the product after mixing in step S122 to 60°C, slowly add 2.5g of styrene-butadiene rubber latex, stir at 380r / min for 18min to avoid local demulsification, and degas under vacuum of -0.095MPa for 14min to obtain the resin modifier.

[0094] The preparation of modified sulfur includes the following steps:

[0095] S11. Heat 31g of sulfur to a molten state and add 0.95g of dicyclopentadiene. Stir at 240r / min for 14min at 138℃.

[0096] S12. Add 5.5g of resin modifier, 0.6g of γ-aminopropyltriethoxysilane and 1.1g of nano-silica to the product obtained in step S11, and continue stirring at 280r / min for 14min at 138℃ to obtain modified sulfur.

[0097] The preparation of fiber modifiers includes the following steps:

[0098] S21. Dissolve 0.36g of dopamine hydrochloride in 28g of Tris-HCl buffer, add 3.6g of polyvinyl alcohol fiber, and react with shaking at 95r / min at 38℃ for 11.5h. Wash with deionized water until the water is clear, and dry at 60℃ to obtain PDA modified fiber.

[0099] S22. Disperse 0.7g of nano-silica in 11g of anhydrous ethanol at a frequency of 40kHz, add 0.56g of KH-560 and 0.36g of isopropyltris(dioctylpyrophosphoryloxy)titanate and continue ultrasonic dispersion for 14min to obtain a dispersion.

[0100] S23. Add the PDA-modified fiber obtained in step S21 to the dispersion obtained in step S22, stir at 240 r / min at 50℃ for 1.5 h, filter to remove the fiber, wash three times with ethanol, and vacuum dry at 70℃ for 3.5 h to obtain the fiber modifier.

[0101] S1. Mix 65g of lake sand and 7g of waste glass powder evenly and preheat to 138℃ to obtain a preliminary mixture;

[0102] S2. Add 34g of modified sulfur and 4g of fiber modifier to the preliminary mixture obtained in step S1, maintain the temperature at 138℃, and stir at a speed of 280r / min for 14min to obtain the secondary mixture.

[0103] S3. Pour the secondary mixture obtained in step S2 into a preheated (138°C) mold, keep it at 138°C for 14 minutes, and after cooling and demolding, obtain polyvinyl alcohol fiber composite modified sulfur-based adhesive.

[0104] Comparative Example 1

[0105] The only difference between Comparative Example 1 and Example 1 is that no resin modifier or fiber modifier was added in this comparative example; the other steps are exactly the same in Comparative Example 1 and Example 1.

[0106] Comparative Example 2

[0107] The only difference between Comparative Example 2 and Example 1 is that the modified sulfur is replaced with ordinary sulfur in this comparative example, while the other steps are exactly the same in Comparative Example 2 and Example 1.

[0108] Performance testing:

[0109] The compressive and flexural strengths of the polyvinyl alcohol fiber-modified sulfur-based adhesives obtained in Examples 1-4 and Comparative Examples 1-2 were tested according to GB / T 17671-1999 "Test Methods for Strength of Cement Mortar". The data are shown in Table 1 below:

[0110] Table 1 Compressive strength and flexural strength

[0111]

[0112] Based on the characteristics of sulfur thermoplastic condensation, the final strength was determined after 1 day during the research process of this invention. As can be seen from the data in Table 1, the polyvinyl alcohol fiber composite modified sulfur-based adhesives obtained in Examples 1-4 are significantly better than those in Comparative Examples 1-2 in terms of compressive strength and flexural strength. This demonstrates the synergistic reinforcing effect of resin modifier, modified sulfur, and fiber modifier. The brittleness of sulfur is effectively improved, and the toughness of the matrix is ​​enhanced.

[0113] Referring to JG / T 24-2000 "Synthetic Resin Emulsion Sand-textured Architectural Coatings", GB / T 17671-1999, and GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete", the bond strength, acid and alkali corrosion resistance, and drying shrinkage of the polyvinyl alcohol fiber composite modified sulfur-based adhesives obtained in Examples 1-4 and Comparative Examples 1-2 were tested respectively. The results are shown in Table 2 below.

[0114] Table 2. Test results of bond strength, acid and alkali corrosion resistance, and drying shrinkage.

[0115]

[0116] The data in Table 2 show that the polyvinyl alcohol fiber composite modified sulfur-based adhesives obtained in Examples 1-4 have better drying shrinkage, bonding strength, and acid corrosion resistance than the comparative examples. This indicates that the synergistic effect of the resin modifier, modified sulfur, and fiber modifier effectively inhibits shrinkage deformation, improves crack resistance, and has a high strength retention rate in acidic environments. This suggests that the stable structure formed by the modified sulfur itself, the dense network formed by the resin modifier, and the fiber modifier blocking the penetration path of corrosive media work together to successfully prepare a polyvinyl alcohol fiber composite modified sulfur-based adhesive with high strength, high toughness, high durability, and excellent workability, thus comprehensively solving the inherent defects of traditional sulfur-based materials.

[0117] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a polyvinyl alcohol fiber composite modified sulfur-based adhesive, characterized in that, The preparation steps include the following: S1. By weight, mix 62-66 parts of aggregate and 4-8 parts of mineral filler evenly and preheat to 130-140℃ to obtain a preliminary mixture; S2. Add 30-35 parts of modified sulfur and 2-5 parts of fiber modifier to the preliminary mixture obtained in step S1, maintain the temperature at 130-140℃, and stir at a speed of 200-300r / min for 10-15min to obtain the secondary mixture. S3. Pour the mixture obtained in step S2 into a preheated mold, keep it at 130-140℃ for 10-15 minutes, and after cooling and demolding, obtain polyvinyl alcohol fiber composite modified sulfur-based adhesive. The preparation of the modified sulfur includes the following steps: S11. By mass, heat 28-32 parts of sulfur to a molten state and add 0.8-1 parts of dicyclopentadiene, and stir at 200-250 r / min for 10-15 min at 130-140℃. S12. Add 4-6 parts of resin modifier, 0.3-0.7 parts of γ-aminopropyltriethoxysilane and 0.8-1.2 parts of nano-silica to the product obtained in step S11, and continue to stir at 250-300 r / min for 10-15 min at 130-140℃ to obtain modified sulfur. The preparation of the fiber modifier includes the following steps: S21. Dissolve 0.3-0.4 parts of dopamine hydrochloride in 26-30 parts of Tris-HCl buffer by weight, add 3-4 parts of polyvinyl alcohol fiber, shake and react at 35-40℃ for 10-12h, wash with deionized water until the water is clear, and dry at 60℃ to obtain PDA modified fiber. S22. Disperse 0.4-0.6 parts of nano-silica ultrasonically in 8-12 parts of anhydrous ethanol, add 0.4-0.6 parts of KH-560 and 0.2-0.4 parts of isopropyltris(dioctylpyrophosphate)titanate and continue ultrasonic dispersion for 10-15 min to obtain a dispersion. S23. Add the PDA modified fiber obtained in step S21 to the dispersion obtained in step S22, stir at 200-250 r / min at 50℃ for 1-2 h, filter to remove the fiber, wash with ethanol 2-3 times, and vacuum dry at 70℃ for 3-4 h to obtain the fiber modifier. The preparation of the resin modifier includes the following steps: S121. By weight, heat 2-4 parts of epoxy resin E-51 and 0.8-1.2 parts of polyurethane prepolymer to 75-80℃ and stir at 200-300 r / min for 15-20 min. S122. While maintaining the temperature, add 1.6-2 parts of methylhexahydrophthalic anhydride, 0.05-0.07 parts of 2,4,6-tris(dimethylaminomethyl)phenol, 0.3-0.5 parts of KH-560 and 0.08-0.12 parts of antioxidant 1010 to the mixture obtained in step S121 and stir for 20-25 minutes. S123. Cool the product after mixing in step S122 to 60°C, slowly add 1-3 parts of styrene-butadiene rubber latex, stir at a speed of 350-400 r / min for 15-20 min to avoid local demulsification, and degas under a vacuum of -0.095 MPa for 10-15 min to obtain the resin modifier.

2. The preparation method of the polyvinyl alcohol fiber composite modified sulfur-based adhesive according to claim 1, characterized in that, The mineral filler is selected from one or more of the following: fly ash, silica fume, coal gangue powder, waste glass powder, sludge ash, metallurgical dust, slag powder, rice husk ash, and straw ash.

3. The preparation method of the polyvinyl alcohol fiber composite modified sulfur-based adhesive according to claim 1, characterized in that, The aggregate is selected from one or more of the following: river sand, quartz sand, manufactured sand, lake sand, tailings sand, recycled fine aggregate, and aeolian sand.

4. The preparation method of the polyvinyl alcohol fiber composite modified sulfur-based adhesive according to claim 1, characterized in that, The preheating temperature in step S3 is 130-140℃.

5. The preparation method of the polyvinyl alcohol fiber composite modified sulfur-based adhesive according to claim 1, characterized in that, The oscillation reaction speed in step S21 is 80-100 r / min.

6. The preparation method of the polyvinyl alcohol fiber composite modified sulfur-based adhesive according to claim 1, characterized in that, In step S22, the frequency of ultrasonic dispersion is 40 kHz.

7. The preparation method of the polyvinyl alcohol fiber composite modified sulfur-based adhesive according to claim 1, characterized in that, The stirring speed in step S122 is 350-400 r / min.

8. A polyvinyl alcohol fiber composite modified sulfur-based adhesive, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

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