Coupled polymer asphalt modifier, its preparation and application in asphalt modification

Abstract

The present invention belongs to the field of asphalt polymer modification, and specifically relates to a coupled polymer asphalt modifier, which comprises a coupled polymer A and a coupled polymer B; the coupled polymer A is expressed as (SB) n1 X1; the expression of the coupled polymer B is [S1-(S2 / B)] n2 X2. The present invention also provides the preparation and application of the modifier, as well as a waterproofing membrane containing the modifier. The present invention has discovered that the combination of dual-coupling polymers A and B can produce synergy, effectively improving the asphalt modification effect.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt modification, and particularly relates to a coupled polymer asphalt modifier. Background Art

[0002] With the development of modern science and technology and the construction industry, people's requirements for the quality of waterproof membranes, construction safety, and environmental protection are constantly increasing. Self-adhesive polymer modified asphalt waterproof membranes eliminate the safety and environmental pollution problems caused by hot-melt construction, and are therefore increasingly attracting attention and favor from the industry.

[0003] Self-adhesive polymer modified asphalt waterproof membrane is a self-adhesive waterproof membrane with polymer modified asphalt as the base material, the surface of which is covered with isolation materials such as polyethylene film or aluminum film, and has no base or polyester base reinforcement.

[0004] Self-adhesive polymer modified asphalt waterproofing membranes have high requirements for the high temperature stability, low temperature flexibility, bonding strength and adhesion of the matrix material. Adding SBS to self-adhesive membranes can improve the high temperature stability and low temperature performance of asphalt, but SBS itself has poor viscosity, and a single SBS modifier is difficult to meet various performance requirements. Commercially available waterproofing membranes usually add a variety of modifiers such as powdered styrene-butadiene rubber (SBR), SIS, and thickening resins. However, the self-adhesive modified asphalt waterproofing membranes in the above-mentioned prior art still have some problems. For example, some membranes use two modifiers, SBS and SBR. SBS and SBR have different melting temperatures in asphalt, and SBR contains a small amount of gel, which is not conducive to melting processing; some use SBS, SIS, and thickening resin as modifiers. The bonding performance is better than that of the SBS modifier alone, but the low temperature flexibility is poor, and at around -20°C, it is difficult to meet higher requirements. Summary of the Invention

[0005] The first object of the present invention is to provide a coupled polymer asphalt modifier (also referred to as a coupled polymer asphalt modifier for modified asphalt in the present invention), the composite composition having high production efficiency, excellent high and low temperature performance, and high bonding strength.

[0006] The second object of the present invention is to provide a method for preparing the coupled polymer asphalt modifier.

[0007] The third object of the present invention is to provide a modified asphalt to which the coupled polymer asphalt modifier is added.

[0008] The fourth object of the present invention is to provide an application of the modified asphalt, which can be used to prepare a self-adhesive polymer modified asphalt waterproof roll with excellent performance, and the prepared waterproof roll has comprehensive excellent properties such as heat resistance, low temperature resistance and high peel strength.

[0009] In order to achieve the above technical objectives, the present invention provides a coupled polymer asphalt modifier, comprising a coupled polymer A and a coupled polymer B;

[0010] The expression of the coupled polymer A is (SB) n1 X1;

[0011] The expression of the coupled polymer B is [S1-(S2 / B)] n2 X2;

[0012] SB and S1-(S2 / B) are polymer arms, where SB is a styrene-butadiene diblock; S1 is a styrene block, and S2 / B is a random copolymer of butadiene and styrene;

[0013] n1 and n2 are the number of polymer arms, and X1 and X2 are coupling residues.

[0014] The present invention has found that the combination of double-coupled polymers A and B can produce synergy and effectively improve the effect of asphalt modification.

[0015] Preferably, in polymer A, n1 is 1 to 4; preferably 3 to 4;

[0016] Preferably, the coupling efficiency (CE) of polymer A is greater than or equal to 85%, preferably 85 to 95%.

[0017] Preferably, the total styrene content of polymer A is in the range of 35-40%; the number average molecular weight (Mn) is in the range of 250,000-300,000; and the tensile strength is greater than 20 MPa.

[0018] In the present invention, polymer A under the parameters can have better synergy with polymer B, can effectively improve the heat resistance and cohesive strength of the modified asphalt, and improve low-temperature flexibility; the product is an expanded particle with a fast melting rate in asphalt, which can improve processing performance.

[0019] Preferably, the viscosity of the toluene solution of polymer A (25° C., 15%) is 500 to 1500 mPa.s, preferably 600 to 1000 mPa.s.

[0020] Preferably, in polymer B, n2 is 2 to 4;

[0021] Preferably, the coupling efficiency of polymer B is 15 to 30%, preferably 20 to 25%.

[0022] Preferably, in polymer B, the ratio of S1 to S2 is greater than or equal to 2:1; more preferably, it is 2 to 4:1.

[0023] Preferably, the total styrene content of polymer B is 15-25%, more preferably 18-23%. The number average molecular weight is 240,000-320,000, more preferably 270,000-300,000. The random structure content of the polybutadiene / styrene chain segments is 85-95%, and the tensile strength is greater than 4 MPa.

[0024] Preferably, the viscosity of the toluene solution of polymer B (25° C., 15%) is 1800 to 3300 mPa.s, preferably 2400 to 2800 mPa.s.

[0025] In the present invention, polymer B under the preferred parameters has a lower content of polystyrene structure and a higher content of butadiene / styrene random copolymer structure. When used in combination with polymer A, it can exhibit better synergy, which helps to further improve the low-temperature resistance and bonding strength of the modified asphalt. In addition, the coupled structure improves the cohesion of the polymer, which can reduce the cold flow of the random polymer and solve the problem of low-strength random polymer agglomerating into powder and difficulty in equipment feeding, thereby improving the adaptability and output of industrial production.

[0026] Preferably, the mass ratio of polymer A to polymer B is 3 / 7 to 7 / 3, more preferably 4 / 6 to 6 / 4.

[0027] The present invention also provides a method for preparing the coupled polymer asphalt modifier, which comprises preparing polymer A and polymer B, and then mixing the two to obtain the coupled polymer asphalt modifier.

[0028] In the present invention, polymer A and polymer B can be prepared by existing methods.

[0029] For example, the preparation process of polymer A is:

[0030] Step (1):

[0031] Styrene, polymerization solvent, alkyl lithium initiator, and regulator are preliminarily subjected to a first stage polymerization reaction to obtain S-Li;

[0032] Step (2):

[0033] After the polymerization in step (1) is completed, the temperature of the polymerization system is controlled to be less than or equal to 95° C. (preferably 60 to 95° C.), and then butadiene is introduced to carry out the second stage polymerization to obtain SB-Li;

[0034] Step (3):

[0035] A coupling agent is added to the polymerization system of step (2) to carry out a coupling reaction to obtain the polymer A; the coupling agent is a chlorosilane, preferably silicon tetrachloride. The molar ratio of the coupling agent to the active lithium (alkyl lithium initiator) is 0.25 to 0.32. The alkyl lithium initiator is preferably a C1 to C4 alkyl lithium, and its amount is, for example, 1 to 1.6 mmol / 100 g of total monomers. The regulating agent is, for example, THF, and its volume concentration in the polymerization solvent is, for example, 0.01 to 0.06 mL / L.

[0036] Preferably, the polymer B glue is prepared by the following method: first, a portion of styrene monomer is added to a polymerization reactor filled with a solvent to react to form polystyrene blocks; then, the remaining styrene monomer and butadiene monomer are mixed evenly in a mixer, and continuously and slowly added to the reactor to form butadiene / styrene random segments; and then, a coupling agent is added to react to obtain the polymer B glue.

[0037] For example, the preparation process of polymer B is:

[0038] Step (a):

[0039] Styrene, polymerization solvent, alkyl lithium initiator, and regulator are preliminarily subjected to a first stage polymerization reaction to obtain S1-Li;

[0040] Step (b):

[0041] After the polymerization in step (a) is completed, the temperature of the polymerization system is controlled to be 70-95° C., and then a mixed monomer comprising styrene and butadiene is slowly and continuously introduced to carry out a second stage of random copolymerization to obtain S1-(S2 / B)-Li;

[0042] Step (c):

[0043] A coupling agent is added to the polymerization system of step (b) to carry out a coupling reaction to obtain the polymer B. The coupling agent is a chlorosilane, preferably a dialkyldichlorosilane. The molar ratio of the coupling agent to the active lithium (alkyllithium initiator) is 0.075 to 0.15. The alkyllithium initiator is preferably a C1 to C4 alkyllithium, and its amount is, for example, 0.6 to 1.5 mmol / 100 g of total monomer. The regulating agent is, for example, THF, and its volume concentration in the polymerization solvent is, for example, 0.01 to 0.06 mL / L.

[0044] For example, the adhesive liquid of polymer A and the adhesive liquid of polymer B are mixed evenly, and then coagulated, expanded, dried and pelletized; or the rubber particles of polymer A and the rubber particles of polymer B are mixed evenly in a mixer to obtain the coupled polymer asphalt modifier.

[0045] The present invention also provides an application of the coupled polymer asphalt modifier, which is used as an asphalt modifier.

[0046] The preferred application is to use it as a modifier for asphalt waterproofing membranes;

[0047] In a further preferred application, the waterproof membrane is a flame-baked or self-adhesive waterproof membrane.

[0048] The present invention also provides a modified asphalt of the coupled polymer asphalt modifier, comprising the coupled polymer asphalt modifier, petroleum asphalt, a plasticizer, an antioxidant and an inorganic filler.

[0049] Preferably, the petroleum asphalt includes one of the asphalts labeled 10# to 110#, and 90# asphalt is more preferred.

[0050] Preferably, the plasticizer is at least one of naphthenic oil, white oil, engine oil, third-line oil, and fourth-line oil. More preferably, third-line oil is used.

[0051] Preferably, the antioxidant is antioxidant 1010.

[0052] Preferably, the inorganic filler includes at least one of calcium carbonate, white carbon black, talc, cement powder and kaolin.

[0053] The modified asphalt of the present invention comprises 50-55 parts of petroleum asphalt, 5-15 parts of plasticizer, 3-7 parts of coupled polymer asphalt modifier, 0.2-0.6 parts of antioxidant and 5-12 parts of inorganic filler.

[0054] The present invention also provides a method for preparing the coupled polymer asphalt modifier-modified asphalt, and the preparation method is as follows:

[0055] 1) Weigh the above raw materials according to the formula weight;

[0056] 2) Preparation of polymer-modified asphalt: petroleum asphalt and plasticizer are added to a reactor, heated to 150-160°C, and stirred to melt; a coupled polymer asphalt modifier and antioxidant 1010 are added, and stirred at a speed of 60-100 r / min for 20-30 minutes to allow the modifier to fully swell; the temperature is raised to 180-190°C, and sheared in a high-shear mixer emulsifier at a shear rate of 4000-4500 r / min for 30-40 minutes; an inorganic filler is added, and the mixture is stirred evenly to obtain the polymer-modified asphalt.

[0057] The present invention also provides an application of the polymer modified asphalt, wherein the polymer modified asphalt is used to prepare a self-adhesive polymer modified asphalt waterproofing membrane.

[0058] The present invention also provides a waterproof roll material, comprising the modified asphalt;

[0059] Preferably, it comprises a carrier, and the modified asphalt compounded on the carrier.

[0060] Beneficial effects:

[0061] 1. The present invention provides a dual-coupled polymer asphalt modifier composed of coupled polymers A and B. The combination of these polymers creates a synergistic effect, improving the overall performance of the modified asphalt. For example, coupled polymer A imparts the modified asphalt with excellent high-temperature performance, cohesive strength, and low-temperature flexibility, while coupled polymer B imparts excellent low-temperature performance and adhesive strength. The synergistic effect of the two polymers results in a polymer-modified asphalt with a high softening point, excellent low-temperature flexibility, good tack retention, and high peel strength.

[0062] 2. The coupled polymers A and B of the present invention have specific structures and molecular weights and can be obtained by anionic polymerization. The products are in the form of fluffy particles. As modifiers, they have a fast swelling rate and a short melting time in asphalt, overcoming the defects of complex melting procedures and poor melting processing performance of SBS combined with multiple modifiers such as SBR and SIS in asphalt.

[0063] 3. The preparation process of the polymer modified asphalt of the present invention is simple, the process conditions are mature, the efficiency is high, and it is conducive to industrial production and application.

[0064] 4. The self-adhesive polymer modified asphalt waterproof membrane prepared by the present invention exhibits good comprehensive performance, with a softening point of over 106°C, low-temperature flexibility without cracks below -29°C, peel strength ≥1.8N / mm, and sustained adhesion ≥54min. DETAILED DESCRIPTION

[0065] The following examples are intended to illustrate the present invention but are not intended to limit the present invention in any way.

[0066] In the embodiment:

[0067] The softening point of modified asphalt was measured using an HDLR-IV asphalt high temperature softening point tester.

[0068] The low-temperature flexibility of modified asphalt was measured using a fully automatic low-temperature flexibility tester.

[0069] The peel strength of modified asphalt was measured using a BLD-200N electronic peel testing machine.

[0070] The CZY-6S adhesion tester was used to measure the adhesion of modified asphalt.

[0071] Performance testing method:

[0072] Softening point is carried out according to GB / T 4507-2014;

[0073] Low temperature flexibility is carried out in accordance with GB / T 328.14;

[0074] Peel strength is carried out according to GB / T 328.20;

[0075] The stickiness is tested according to 5.15 of GB / T 35467-2017;

[0076] Heat resistance is tested according to method B in GB / T 328.11;

[0077] The water-impermeability test is carried out according to Method B in GB / T 328.10.

[0078] Example 1

[0079] To a 5-liter polymerization kettle, 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added, stirred, and heated to 50-60°C. 105 g of styrene was added, and 7.5 ml of 0.5 mol / L n-butyl lithium was added via syringe to initiate styrene. After reacting for 20-25 minutes, 195 g of butadiene was pressurized with nitrogen to carry out a second stage reaction. The temperature was controlled at 65-95°C for 25-30 minutes, and then 2.9 ml of 0.4 mol / L silicon tetrachloride was added to carry out a third stage reaction. After reacting for 15-20 minutes, a coupled polymer A1 gel having a mass concentration of 13.3% cyclohexane solution was obtained. The measured Mn = 262,000 and the coupling efficiency was 89.8%.

[0080] Example 2

[0081] In Example 1, other conditions remained unchanged, except that the amounts of styrene, n-butyl lithium, butadiene, and silicon tetrachloride were set to 114 g, 7.3 ml, 186 g, and 2.6 ml, respectively. The results showed that the mass concentration of the coupled polymer A2 solution was 13.3%, Mn = 274,000, and the coupling efficiency was 94.6%.

[0082] Example 3

[0083] In Example 1, other conditions remained unchanged, except that the amounts of styrene, n-butyl lithium, butadiene, and silicon tetrachloride were set to 120 g, 7.0 ml, 180 g, and 2.2 ml, respectively. The results showed that the mass concentration of the coupled polymer A3 solution was 13.3%, Mn = 289,000, and the coupling efficiency was 85.2%.

[0084] Example 4

[0085] In a 5-liter polymerization kettle, 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added, and 4.3 ml of 0.5 mol / L n-butyl lithium was added. 45 g of styrene was polymerized in a first stage. 21 g of styrene (S / B = 7 / 78) and 234 g of butadiene were mixed in a mixer. The mixed monomers were then slowly and continuously pressed into the polymerization kettle for a second stage reaction. The temperature was controlled at 70-95°C. In the third stage, 1.6 ml of 0.2 mol / L dichlorodimethylsilane was added for coupling. The coupling time was 15-20 min to obtain [S1-(S2 / B)] n The Si glue (coupling polymer B1) has a mass concentration of 13.3%, a measured Mn of 285,000, a coupling efficiency of 24.5%, and a random structure content of the polybutadiene / styrene chain segment of 86.0%.

[0086] Example 5

[0087] In Example 4, other conditions remained unchanged, except that the amounts of n-butyl lithium, primary styrene, secondary styrene, butadiene, and dichlorodimethylsilane were set to 4.5 ml, 54 g, 15 g, 231 g, and 1.1 ml, respectively. The results showed that the mass concentration of the coupled polymer B2 solution was 13.3%, Mn = 270,000, the coupling efficiency was 20.2%, and the random structure content of the polybutadiene / styrene chain segments was 93.8%.

[0088] Example 6

[0089] In Example 4, other conditions remained unchanged, except that the amount of n-butyl lithium was set to 6.3 ml, the amount of primary styrene to 36 g, the amount of secondary styrene to 18 g, and the amount of butadiene to 246 g. Dichlorodimethylsilane was replaced with silicon tetrachloride (0.4 mol / L), the amount of which was set to 0.6 ml. The results showed that the mass concentration of the coupled polymer B3 solution was 13.3%, Mn = 301,000, the coupling efficiency was 23.5%, and the random structure content of the polybutadiene / styrene chain segments was 90.5%.

[0090] Example 7

[0091] The coupled polymer A glue in Examples 1, 2, and 3 and the coupled polymer B glue in Examples 4, 5, and 6 were mixed evenly in different proportions, and 0.25% 1076 and 0.25% 168 were added and stirred evenly. After condensation with water vapor and hot air drying, the particles were cut into ∮(2-3)×(2-6) mm particles and numbered 1#, 2#, 3#, 4#, 5#, 6#, and 7# for later use.

[0092] The compositions of the coupled polymer asphalt modifiers are shown in Table 1.

[0093] Table 1 Composition of each coupled polymer asphalt modifier (by weight)

[0094]

[0095] Example 8

[0096] 1400g of 90# petroleum asphalt was evenly divided into seven portions (Table 1) and placed in 500ml beakers. 40g of three-line oil was added to each of the seven beakers of asphalt sample, and the mixture was heated to melt, maintaining the system temperature at 155°C. 20g of the coupled polymer asphalt modifier samples 1# to 7# from Example 7 was then added to the beaker, along with 0.6g of antioxidant 1010. The mixture was stirred and allowed to melt for 30 minutes. A high-shear emulsifier was then used to shear the mixture at 4000 rpm for 30 minutes, maintaining the system temperature at 180°C. 35g of talc was then added and stirred until uniformly mixed to produce the polymer-modified asphalt. The modified asphalt was evenly coated onto a PET nonwoven fabric and cooled to room temperature to produce a self-adhesive polymer-modified asphalt waterproofing membrane.

[0097] The test results of each modified asphalt are shown in Table 2 below.

[0098] Table 2 Properties of asphalt waterproof membranes modified with coupled polymer asphalt modifiers prepared in Examples 1# to 7#

[0099]

[0100] Comparative Example 1

[0101] Compared with Example 1, the main difference is that no SB coupled polymer is formed, specifically:

[0102] 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added to a 5-liter polymerization kettle, stirred and heated to 50-60°C, 52.5 g of styrene was added, and 5.0 ml of 0.5 mol / L n-butyl lithium was added by syringe to initiate styrene. After reacting for 20-25 minutes, 195 g of butadiene was pressurized with nitrogen to carry out the second stage reaction. The temperature was controlled at 65-90°C to react for 25-30 minutes, and then 52.5 g of styrene was added to carry out the third stage reaction. After reacting for 20-25 minutes, an SBS glue with a mass concentration of 13.3% cyclohexane solution was obtained, and Mn was measured to be 123,000.

[0103] Comparative Example 2

[0104] Compared with Example 4, the main difference is that no SS / B copolymer arms are formed, specifically:

[0105] To a 5-liter polymerization kettle, 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added, stirred, and heated to 50-60°C. 90 g of styrene was added, and 9.5 ml of 0.5 mol / L n-butyl lithium was added via syringe to initiate the styrene reaction. After a reaction time of 20-25 minutes, 210 g of butadiene was introduced by nitrogen pressure for a second reaction. The temperature was controlled at 70-95°C for 25-30 minutes, and then 2.5 ml of 0.4 mol / L silicon tetrachloride was added for a third reaction. After a reaction time of 15-20 minutes, a (SB)nSi gel solution having a mass concentration of 13.3% cyclohexane solution was obtained. The measured Mn value was 243,000, and the coupling efficiency was 90.5%.

[0106] Comparative Example 3

[0107] 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added to a 5-liter polymerization kettle, stirred and heated to 55-65°C, 22.5 g of styrene was added, and 4.4 ml of 0.5 mol / L n-butyl lithium was added with a syringe to initiate styrene. After reacting for 20-25 minutes, 255 g of isoprene was pressurized with nitrogen to carry out the second stage reaction. The temperature was controlled at 65-85°C to react for 25-30 minutes, and then 22.5 g of styrene was added to carry out the third stage reaction. After reacting for 20-25 minutes, a SIS glue with a mass concentration of 13.3% cyclohexane solution was obtained, and Mn was measured to be 135,000.

[0108] Comparative Example 4

[0109] To a 5-liter polymerization kettle, 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added, stirred, and heated to 50-60°C. 105 g of styrene was added, and 2.3 ml of 0.5 mol / L n-butyl lithium was added via a syringe to initiate the styrene reaction. After reacting for 20-25 minutes, 195 g of butadiene was pressurized with nitrogen to carry out a second stage reaction. The temperature was controlled at 70-90°C, and the reaction was continued for 25-30 minutes to obtain an SB glue solution with a mass concentration of 13.3% cyclohexane solution. Mn was measured to be 260,000.

[0110] Comparative Example 5

[0111] 2500 ml of anhydrous cyclohexane and 0.1 ml of tetrahydrofuran were added to a 5-liter polymerization kettle, stirred and heated to 50-60°C, 45 g of styrene was added, and 2.2 ml of 0.5 mol / L n-butyl lithium was added via a syringe to initiate styrene. After reacting for 20-25 minutes, the mixed monomers (21 g of styrene and 234 g of butadiene) were slowly and continuously pressed into the polymerization kettle for a second-stage reaction. The temperature was controlled at 70-95°C. After reacting for 25-30 minutes, an S-(S / B) glue solution was obtained with a mass concentration of 13.3%, a measured Mn of 275,000, and a random structure content of the polybutadiene / styrene chain segment of 89.8%.

[0112] Comparative Example 6

[0113] 0.25% 1076 and 0.25% 168 were added to the adhesives in Comparative Examples 1, 2, 3, 4, and 5, as well as the adhesive A1 in Example 1 and the adhesive B1 in Example 4. The mixture was stirred evenly, condensed with water vapor, dried with hot air, and then cut into particles of ∮(2-3) x (2-6) mm. The polymer particles, or the polymer particles combined with powdered styrene-butadiene SBR or SIS according to different formulations, were numbered 8#, 9#, 10#, 11#, 12#, 13#, 14#, and 15# and set aside.

[0114] The polymers and their formulations are shown in Table 3.

[0115] Table 3 Composition of each polymer modifier

[0116]

[0117] Comparative Example 7

[0118] The steps of Example 8 were followed, with other conditions remaining unchanged, except that the coupled polymer asphalt modifier in Example 8 was replaced with the polymer modifier in Table 3. The properties of the modified asphalt waterproof membranes prepared from the various polymers and their combinations are shown in Table 4.

[0119] Table 4 Performance of polymer modified asphalt waterproof membranes prepared from 8# to 15# in comparative examples

[0120] Typical performance 8# 9# 10# 11# 12# 13# 14# 15# Stickiness (min) 25 30 27 33 15 17 36 23 Low temperature flexibility (℃) -22.0 -21.5 -20.0 -19.0 -21 -26 -20 -32 Softening point (℃) 94.1 102.3 94.6 103.2 62.0 64.7 115.0 78.4 Peel strength (N / mm) 1.1 1.3 1.2 1.4 0.5 0.6 1.5 1.1

[0121] In summary, the coupled polymer asphalt modifier described in the present invention can effectively improve the comprehensive properties of modified asphalt, such as low temperature resistance, heat resistance and adhesion.

Claims

1. A coupled polymer asphalt modifier, characterized in that: Comprising a coupled polymer A and a coupled polymer B; The expression of the coupled polymer A is (SB) n1 X1; The expression of the coupled polymer B is [S1-(S2 / B)] n2 X2; SB and S1-(S2 / B) are polymer arms, where SB is a styrene-butadiene diblock; S1 is a styrene block, and S2 / B is a random copolymer of butadiene and styrene; n1 and n2 are the number of polymer arms, and X1 and X2 are coupling residues; In polymer A, n1 is 3 to 4; The coupling efficiency of polymer A was 85–95%; In polymer B, the ratio of S1 to S2 is greater than or equal to 2:1; n2 is 2 to 4; the coupling efficiency of polymer B is 15 to 30%; The mass ratio of polymer A to polymer B is 3 / 7~7 / 3.

2. The coupled polymer asphalt modifier according to claim 1, characterized in that In polymer A, the total styrene content ranges from 35% to 40%; the number average molecular weight is from 250,000 to 300,000; and the tensile strength is greater than 20 MPa.

3. The coupled polymer asphalt modifier according to claim 1, characterized in that The viscosity of the polymer A toluene solution is 500-1500 mPa.s at 25° C. and 15% concentration.

4. The coupled polymer asphalt modifier according to claim 1, wherein The coupling efficiency of polymer B is 20~25%.

5. The coupled polymer asphalt modifier according to claim 1, characterized in that: In polymer B, the ratio of S1 to S2 is 2~4:

1.

6. The coupled polymer asphalt modifier according to claim 1, characterized in that In polymer B, the total styrene content is 15-25%; the number average molecular weight is 240,000-320,000; the random structure content of the polybutadiene / styrene chain segment is 85-95%; and the tensile strength is greater than 4 MPa.

7. The coupled polymer asphalt modifier according to claim 1, characterized in that: The viscosity of polymer B toluene solution is 1800~3300 mPa.s at 25℃ and 15%.

8. The coupled polymer asphalt modifier according to claim 1, characterized in that: The mass ratio of polymer A to polymer B is 4 / 6~6 / 4.

9. A method for preparing the coupled polymer asphalt modifier according to any one of claims 1 to 8, characterized in that: Polymer A and polymer B are prepared and then mixed to obtain the coupled polymer asphalt modifier.

10. The method for preparing the coupled polymer asphalt modifier according to claim 9, wherein: The preparation process of polymer A is as follows: Step (1): Styrene, polymerization solvent, alkyl lithium initiator, and regulator are preliminarily subjected to a first stage polymerization reaction to obtain S-Li; Step (2): After the polymerization in step (1) is completed, the temperature of the polymerization system is controlled to be 60-95° C., and then butadiene is introduced to carry out the second stage polymerization to obtain SB-Li; Step (3): Adding a coupling agent to the polymerization system of step (2) to carry out a coupling reaction to obtain the polymer A; The coupling agent is chlorosilane.

11. The method for preparing the coupled polymer asphalt modifier according to claim 10, wherein: The coupling agent is silicon tetrachloride.

12. The method for preparing the coupled polymer asphalt modifier according to claim 10, wherein: The molar ratio of the coupling agent to the alkyl lithium initiator is 0.25-0.

32.

13. The method for preparing the coupled polymer asphalt modifier according to claim 9, wherein: The preparation process of polymer B is: Step (a): Styrene, polymerization solvent, alkyl lithium initiator, and regulator are preliminarily subjected to a first stage polymerization reaction to obtain S1-Li; Step (b): After the polymerization in step (a) is completed, the temperature of the polymerization system is controlled to be 70-95° C., and then a mixed monomer comprising styrene and butadiene is slowly and continuously introduced to perform a second stage of random copolymerization to obtain S1-(S2 / B)-Li; Step (c): Adding a coupling agent to the polymerization system of step (b) to carry out a coupling reaction to obtain the polymer B; The coupling agent is chlorosilane.

14. The method for preparing the coupled polymer asphalt modifier according to claim 13, wherein: The coupling agent is dialkyldichlorosilane.

15. The method for preparing the coupled polymer asphalt modifier according to claim 14, wherein: The molar ratio of the coupling agent to the alkyl lithium initiator is 0.075-0.

15.

16. Use of the coupled polymer asphalt modifier according to any one of claims 1 to 8, characterized in that: It is used as a modifier for asphalt.

17. The use of the coupled polymer asphalt modifier according to claim 16, characterized in that: It is used as a modifier for asphalt waterproofing membranes.

18. The use of the coupled polymer asphalt modifier according to claim 17, characterized in that: The waterproof coiled material is a fire-baked or self-adhesive waterproof coiled material.

19. A modified asphalt, characterized in that: The invention comprises the coupled polymer asphalt modifier according to any one of claims 1 to 8, petroleum asphalt, a plasticizer, an antioxidant and an inorganic filler.

20. The modified asphalt according to claim 19, characterized in that The petroleum asphalt is at least one of the asphalts with the grades of 10# to 110#.

21. The modified asphalt according to claim 19, wherein The plasticizer is at least one of naphthenic oil, white oil, engine oil, third-line oil, and fourth-line oil.

22. The modified asphalt according to claim 19, wherein The antioxidant is antioxidant 1010.

23. The modified asphalt according to claim 19, wherein The inorganic filler includes at least one of calcium carbonate, white carbon black, talc, cement powder and kaolin.

24. The modified asphalt according to any one of claims 19 to 23, characterized in that 50-55 parts of petroleum asphalt, 5-15 parts of plasticizer, 3-7 parts of coupled polymer asphalt modifier, 0.2-0.6 parts of antioxidant, 5-12 parts of inorganic filler.

25. A waterproof roll, characterized in that: Comprising the modified asphalt according to any one of claims 19 to 24.

26. The waterproof membrane according to claim 25, characterized in that: The invention comprises a carrier, and the modified asphalt according to any one of claims 19 to 24 compounded on the carrier.

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