阅读说明：本技术 一种线性双羟基sbs及其制备方法 (Linear dihydroxy SBS and preparation method thereof ) 是由 李静静 邵磊山 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种线性双羟基SBS的制备方法。本发明采用有机锂为引发剂,双官能团试剂为偶联剂,在偶联反应制备SBS的同时在SBS分子链中引入两个羟基,不仅可以在SBS中引入极性基团,提高SBS分子链的极性,同时具有较快的偶联反应速率,偶联效率可以达到80％以上,产物结构与性能稳定,制备工艺简单。该线性双羟基SBS与极性材料具有良好的相容性。(The invention discloses a preparation method of linear dihydroxy SBS. According to the invention, organic lithium is used as an initiator, a bifunctional reagent is used as a coupling agent, two hydroxyl groups are introduced into an SBS molecular chain while SBS is prepared through a coupling reaction, so that a polar group can be introduced into SBS, the polarity of the SBS molecular chain is improved, the coupling reaction rate is high, the coupling efficiency can reach more than 80%, the product structure and the performance are stable, and the preparation process is simple. The linear dihydroxy SBS has good compatibility with polar materials.)

1. A linear dihydroxy SBS has two hydroxy groups on its linear molecular chain.

2. The linear dihydroxy SBS according to claim 1, wherein the mass ratio of structural units derived from styrene to structural units derived from butadiene in the linear dihydroxy SBS is 40:60 to 20: 80.

3. A preparation method of linear dihydroxy SBS comprises:

1) adding a hydrocarbon solvent, styrene and a polar additive into a reactor, then heating to 30-60 ℃, adding an organic lithium initiator, and carrying out a first-stage polymerization reaction;

2) after the temperature is adjusted to 60-65 ℃, adding butadiene into the reactor to carry out second-stage polymerization reaction;

3) adding a bis-epoxy coupling agent into the reactor to perform coupling reaction; -4) adding a terminating agent into the reactor to terminate the coupling reaction, adding an anti-aging agent, removing the hydrocarbon solvent, and drying to obtain the linear dihydroxy SBS.

4. The method according to claim 3, wherein the structural formula of the bis-epoxy-based coupling agent is represented by formula (1):

in the formula (1), R₁And R₂Are the same or different and are each independently selected from H and C₁-C₆Is preferably H and C₁-C₃Alkyl groups of (a); n is 1 to 30, and the molar ratio of the bis-epoxy coupling agent to the available organic lithium is preferably (0.4 to 3): 1.

5. The production method according to claim 3 or 4, wherein in step 1), the hydrocarbon solvent is selected from at least one of cyclohexane, hexane, pentane, benzene, toluene, and xylene; and/or the polar additive is selected from at least one of diethyl ether, anisole, dioxane, tetrahydrofuran, dimethoxyethane, diglyme, triethylamine, tetramethylethylenediamine and pentamethyldiethylenetriamine; and/or the organolithium initiator is n-butyllithium; preferably, the hydrocarbon solvent is used in an amount such that the mass percentage concentration of the system monomer is 10% -25%; and/or the molar ratio of the polar additive to the effective organic lithium is (0.1-10): 1.

6. The preparation method according to any one of claims 3 to 5, wherein the amount of the butadiene added in step 2) is determined according to the mass ratio of the structural units derived from styrene to the structural units derived from butadiene in the prepared linear dihydroxy SBS being 40:60 to 20: 80.

7. The production method according to any one of claims 3 to 6, wherein the time for the first-stage polymerization reaction is 30 to 60 min; and/or

The time of the second-stage polymerization reaction is 20 min-60 min; and/or

The coupling reaction time is 2 min-30 min.

8. The production method according to any one of claims 3 to 7, wherein the terminator is selected from at least one of water, methanol, ethanol, and isopropanol; preferably, the molar ratio of the terminating agent to the available organic lithium is 1: 1-6: 1.

9. The production method according to any one of claims 3 to 8, wherein the antioxidant is at least one selected from the group consisting of 2, 6-di-t-butyl-p-cresol, t-butyl catechol, 2' -methylene-bis (4-methyl-6-t-butylphenol), and trisnonylphenyl phosphite; preferably, the amount of the anti-aging agent is 0.3-3% of the mass of the prepared linear dihydroxy SBS.

10. Use of the linear dihydroxy SBS according to claim 1 or 2 or prepared according to the preparation method of any one of claims 3 to 9 in the field of plastic materials, coatings and modified materials.

Technical Field

The invention relates to the field of petrochemical industry, in particular to a linear dihydroxy SBS and a preparation method thereof.

Background

Styrene-butadiene-styrene block copolymer (SBS) is a thermoplastic elastomer prepared by adopting an anionic polymerization method, the preparation method comprises a three-step method and a coupling method, and due to the unique structure, the SBS has two performances of rubber and plastic, has elasticity of rubber at normal temperature, can become a plastic material at high temperature, and is widely used in various fields of shoe sole materials, adhesives, asphalt modification, plastic modification and the like. As the molecular structure of the SBS product produced at present does not have other active polar groups, although the SBS product is widely applied to the aspects of shoe making industry, asphalt modification, adhesives, waterproof coiled materials and the like, the bonding property of SBS and other polar materials, the compatibility stability of SBS and asphalt and the like have defects. In addition, the application of SBS in the aspects of blending modification of coating and other materials is relatively lacked. If other active groups are added and connected in SBS molecules to increase the polarity of SBS, the application field of SBS can be widened, the quality of SBS can be further improved, and the defects of SBS can be overcome.

At present, chemical modification functionalization methods (such as SBS grafting reaction, SBS sulfonation and the like) are generally adopted to polarize SBS, secondary processing is needed to be carried out on SBS, the integral structure of SBS chains is damaged, the cost is high, the process is complex, and industrialization is difficult to realize. The anion in-situ polymerization method (including polar monomer in-situ copolymerization and polar group in-situ end capping) can synthesize SBS with polar group in situ, no secondary processing is needed, the product has high functionalization rate and great development potential, but under mild conditions, the anion solution polymerization process can not effectively introduce the polar group-containing monomer, thus greatly limiting the application of the polar monomer in-situ copolymerization method in industry. Compared with polar monomer in-situ copolymerization, the polar group in-situ end capping can introduce the polar group into the SBS tail end through a functionalized initiator or an end capping agent under mild conditions, and the method is simple in process and beneficial to industrialization.

Patent CN101041708A discloses a method for preparing amine-terminated SBS (SBS-N) by using schiff base as anionic polymerization end-capping, and the method is used for modifying asphalt, obviously improving asphalt performance and improving storage stability. Patent CN1923870B discloses a method for preparing storage-stable modified asphalt by using a nitrogen-lithium initiator to initiate and end-capping in-situ synthesis of styrene/butadiene/styrene triblock copolymer with amine and carboxyl groups at two end groups. The introduction of functional groups into SBS can improve its compatibility with asphalt, and therefore there is a trend toward the development of functionalized SBS.

However, the above-mentioned method is to introduce functional groups at the end of SBS by three steps to prepare end group functionalized linear SBS, which has the disadvantages of complicated steps, complex process, many times of feeding, easy introduction of impurities, termination of reaction and long reaction time.

Disclosure of Invention

The invention aims to provide a linear dihydroxy SBS and a preparation method thereof, wherein the preparation method is used for introducing a diepoxy coupling agent to prepare the dihydroxy SBS with a polar functional group by utilizing a coupling method according to an anion polymerization mechanism. The method does not change the original production process for preparing SBS by coupling method, does not need secondary processing treatment on SBS, and has simple preparation process, low cost and easy industrial production. The dihydroxy SBS prepared by the invention has good compatibility with polar materials such as asphalt and the like.

In one aspect, the present invention provides a linear dihydroxy SBS having two hydroxy groups on the linear molecular chain.

In some preferred embodiments of the present invention, in the linear dihydroxy SBS, the mass ratio of structural units derived from styrene to structural units derived from butadiene is 40:60 to 20: 80.

In another aspect, the present invention provides a method for preparing linear dihydroxy SBS, comprising:

1) adding a hydrocarbon solvent, styrene and a polar additive into a reactor, then heating to 30-60 ℃, adding an organic lithium initiator, and carrying out a first-stage polymerization reaction;

2) after the temperature is adjusted to 60-65 ℃, adding butadiene into the reactor to carry out second-stage polymerization reaction;

3) adding a bis-epoxy coupling agent into the reactor to perform coupling reaction;

4) adding a terminating agent into the reactor to terminate the coupling reaction, adding an anti-aging agent, removing the hydrocarbon solvent, and drying to obtain the linear dihydroxy SBS.

In some preferred embodiments of the present invention, the structural formula of the diepoxy coupling agent is represented by formula (1):

in the formula (1), R₁And R₂Are the same or different and are each independently selected from H and C₁-C₆Is preferably H and C₁-C₃Alkyl groups of (a); n is 1 to 30, preferablyOptionally, the molar ratio of the bis-epoxy coupling agent to the effective organic lithium is (0.4-3): 1.

According to the invention, the bis-epoxy-based coupling agent is added to the reaction system in a plurality of times, preferably 2 to 5 times.

According to the invention, the coupling rate of the prepared linear dihydroxy SBS can reach more than 80% by adopting the bis-epoxy coupling agent.

In some preferred embodiments of the present invention, the hydrocarbon solvent is selected from at least one of cyclohexane, hexane, pentane, benzene, toluene, and xylene.

In some preferred embodiments of the present invention, the polar additive is selected from at least one of diethyl ether, anisole, dioxane, tetrahydrofuran, dimethoxyethane, diglyme, triethylamine, tetramethylethylenediamine and pentamethyldiethylenetriamine.

In some preferred embodiments of the present invention, the organolithium initiator is n-butyllithium.

In some preferred embodiments of the present invention, the hydrocarbon solvent is used in an amount to provide a system monomer concentration of 10% to 25% by mass.

In some preferred embodiments of the present invention, the molar ratio of the polar additive to the available organolithium is (0.1-10): 1.

According to the invention, in the reaction, one part of the organic lithium initiator is used for impurity removal, the dosage of the organic lithium initiator is enough for completely removing impurities in the reaction system, namely when the system is unchanged from colorless to light yellow, the impurities in the system are considered to be removed, and the other part of the organic lithium initiator is used as the initiator, namely the effective organic lithium initiator, and the dosage is determined according to the designed relative molecular mass.

In some preferred embodiments of the present invention, in the step 2), the butadiene is added in an amount determined according to that the mass ratio of the structural units derived from styrene to the structural units derived from butadiene in the prepared linear dihydroxy SBS is 40:60 to 20: 80.

In some preferred embodiments of the present invention, the time for the first stage polymerization reaction is 30min to 60 min.

In some preferred embodiments of the present invention, the time for the second stage polymerization reaction is 20min to 60 min.

In some preferred embodiments of the present invention, the coupling reaction time is 2min to 30 min.

In some preferred embodiments of the present invention, the terminator is selected from at least one of water, methanol, ethanol, and isopropanol.

In some preferred embodiments of the present invention, the molar ratio of the terminating agent to the available organolithium is 1:1 to 6: 1.

In some preferred embodiments of the present invention, in step 4), after the addition of the terminator to terminate the coupling reaction, an antioxidant is further added, the antioxidant being selected from at least one of 2, 6-di-t-butyl-p-cresol, t-butyl catechol, 2' -methylene-bis (4-methyl-6-t-butylphenol), and trisnonylphenyl phosphite.

In some preferred embodiments of the present invention, the antioxidant is used in an amount of 0.3 to 3% by mass of the linear dihydroxy SBS produced.

The invention further provides application of the linear dihydroxy SBS or the linear dihydroxy SBS prepared by the preparation method in the fields of plastic materials, coatings and modified materials.

Compared with the prior art, the invention has the following advantages:

the invention adopts the bis-epoxy group coupling agent under the condition of anionic polymerization, introduces the dihydroxy polar functional group into SBS by a coupling method, increases the polarity of SBS, and has the advantages of high coupling rate, simple preparation process, low cost, short polymerization time, low energy consumption and material consumption, easy industrialization and better process application prospect. The prepared dihydroxy SBS has good compatibility with polar materials such as asphalt and the like, and has better performance than common SBS.

Detailed Description

The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to the following description.

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

In the following embodiments, the diepoxy coupling agents referred to are as follows:

the coupling agent 1 is shown as a formula (1), wherein R₁And R₂Is hydrogen, n is 1;

the coupling agent 2 is shown as a formula (1), wherein R₁And R₂Is hydrogen, n is 2;

the coupling agent 3 is shown as a formula (1), wherein R₁And R₂Is methyl, n-3;

the coupling agent 4 is shown as a formula (1), wherein R₁Is methyl, R₂Is hydrogen, n is 3;

the coupling agent 5 is shown as a formula (1), wherein R₁Is ethyl, R₂Is hydrogen, n is 4.

Example 1

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate the first-stage polymerization reaction for 30 min; after the first-stage polymerization reaction is finished, adjusting the temperature to 60-65 ℃, and then pressing 583g of butadiene into a polymerization kettle by using nitrogen for reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 0.4, reacting for 15min, terminating the reaction by using 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final polymerization product. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 2

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 0.6, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final polymerization product. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 3

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate the first-stage polymerization reaction for 30 min; after the first-stage polymerization reaction is finished, adjusting the temperature to 60-65 ℃, and then pressing 583g of butadiene into a polymerization kettle by using nitrogen for reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 0.6, reacting for 5min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

From a comparison of example 2 and example 3, it can be seen that the coupling time does not affect the molecular weight distribution and coupling ratio of the functionalized SBS.

Example 4

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 0.8, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 5

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 1.0, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 6

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 2 twice, wherein the molar ratio of the coupling agent 2 to the effective n-butyl lithium is 0.6, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 7

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 3 twice, wherein the molar ratio of the coupling agent 3 to the effective n-butyl lithium is 0.6, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 8

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 4 twice, wherein the molar ratio of the coupling agent 4 to the effective n-butyl lithium is 0.6, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 9

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 5 twice, wherein the molar ratio of the coupling agent 5 to the effective n-butyl lithium is 0.6, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 10

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to be 60-65 ℃, then pressing 250g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 0.4, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final product of polymerization. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

Example 11

In a 10L polymerization vessel, 4.42kg of cyclohexane, 250g of styrene and tetrahydrofuran were introduced under pressure with nitrogen so that the molar ratio of tetrahydrofuran to n-butyllithium as an initiator to be subsequently added was 0.15. Heating, adding n-butyl lithium to break impurities, and when the system is changed from colorless to light yellow, indicating that the impurities in the system are removed. Then 5.2mL of effective n-butyllithium solution (the molar concentration is 2.43mol/L) is rapidly added at 60 ℃ to initiate polymerization for 30 min; after the first-stage polymerization is finished, adjusting the temperature to 60-65 ℃, then pressing 583g of butadiene into a polymerization kettle by using nitrogen, and reacting for 35 min; then adding the coupling agent 1 twice, wherein the molar ratio of the coupling agent 1 to the effective n-butyl lithium is 5, reacting for 15min, terminating with 1.5mL of ethanol, and adding 0.6 mass percent of anti-aging agent according to the mass of the final polymerization product. The anti-aging agent is 2, 6-di-tert-butyl-p-cresol and 2, 2' -methylene-bis (4-methyl-6-tert-butylphenol). And after the polymerization is finished, the reaction product is subjected to gas stripping to remove cyclohexane, and then the product is dried to obtain the dihydroxy SBS, wherein the molecular weight, the molecular weight distribution and the coupling rate of the polymerization product are shown in table 1, and the mechanical properties are shown in table 2.

TABLE 1

As can be seen from the data in Table 1, the linear dihydroxy SBS prepared by the method provided by the invention has proper molecular weight and molecular weight distribution width, and the coupling agent adopted by the invention has higher coupling rate.

TABLE 2

As can be seen from the data in Table 2, the linear dihydroxy SBS prepared by the method provided by the invention has better comprehensive performance.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.