Preparation method and application of epoxidized medium-high vinyl liquid polybutadiene

Abstract

The invention belongs to the field of rubber materials, and particularly relates to a preparation method and application of epoxidized medium-high vinyl liquid polybutadiene, a butadiene solution, a conditioning agent and an initiator are subjected to an anionic polymerization reaction, and then the product and hydrogen are subjected to an end-capping termination reaction to obtain end-capped medium-high vinyl liquid polybutadiene; and reacting the terminated medium-high vinyl liquid polybutadiene with formic acid, and then performing epoxidation modification reaction with hydrogen peroxide to obtain the epoxidized medium-high vinyl liquid polybutadiene. The obtained epoxidized medium-high vinyl polybutadiene rubber can be used as a compatilizer, has good compatibility with solution polymerized styrene-butadiene rubber and white carbon black, is stable in performance after being compounded, and has wide market application and development prospects in preparation of green tires.

Description

Technical Field

[0001] The present invention belongs to the field of rubber materials, and specifically relates to a preparation method and application of epoxidized medium-high vinyl liquid polybutadiene. Background Art

[0002] Solution-polymerized styrene-butadiene rubber (SSBR) synthesized by living anionic polymerization can meet the requirements of various high-performance tires for tread rubber. Studies have found that there are two main reasons for the rolling resistance of tires. First, due to the free chain ends in the rubber cross-linking network, it cannot effectively participate in the elastic recovery process during periodic cyclic deformation, resulting in hysteresis and energy loss; second, due to the hysteresis caused by the binding and detachment between rubber macromolecules and reinforcing agents, energy loss is caused. At present, white carbon black is widely used as a reinforcing agent in solution-polymerized styrene-butadiene rubber tread rubber. However, due to the presence of a large number of hydroxyl groups on the surface of white carbon black, the surface polarity is strong, making it easy for particles to interact with each other and easily agglomerated, so its surface is generally hydrophilic and oleophobic, making it difficult for white carbon black to infiltrate and disperse in the organic phase, making it less compatible with rubber macromolecules, resulting in reduced rubber processing, vulcanization and mechanical properties. Therefore, it is usually necessary to add a compatibilizer during the SSBR processing in order to increase the compatibility of the solution-polymerized styrene-butadiene rubber matrix and the silica filler and prepare a new energy-saving tire that has both anti-skid properties and low rolling resistance.

[0003] The present invention proposes to adopt a microchannel polymerization reactor, an epoxidation static mixer and a time-delay tube reactor in series combination to prepare epoxidized medium-high vinyl polybutadiene as a compatibilizer for SSBR rubber. Polybutadiene rubber is the world's second largest general-purpose synthetic rubber, second only to styrene-butadiene rubber, synthesized using butadiene as a monomer and different catalysts and polymerization methods. According to its microstructural differences, it can be divided into five products: high cis polybutadiene rubber, low cis polybutadiene rubber, medium vinyl polybutadiene rubber, high vinyl polybutadiene rubber and high trans polybutadiene rubber. Among them, medium-high vinyl polybutadiene rubber has excellent anti-slip performance and low rolling resistance, and wear resistance also maintains a good level, which is suitable for the development requirements of current green tires. When liquid polybutadiene is used for the volume expansion of SSBR, it is necessary to solve the problem that its molecular chain polarity is very low and it is difficult to be compatible with the polar filler in the processing of SSBR. Epoxidation modification can enable polybutadiene rubber to overcome the above-mentioned shortcomings, introduce epoxy groups, and achieve performance synergy between SSBR and white carbon black in processing.

[0004] At present, domestic literature and patents on the epoxidation modification of polybutadiene rubber are mainly focused on liquid polybutadiene with relatively low molecular weight, and the epoxidation research on high molecular weight polybutadiene rubber is focused on polybutadiene rubber with high cis-1,4 structure content or 1,2-polybutadiene with 1,2-structure content greater than 95%. CN104448059A discloses a method for preparing a high cis-1,4 hydroxyl-containing polybutadiene liquid rubber, wherein the epoxidized cis-1,4 hydroxyl-containing polybutadiene liquid rubber is reacted in a reaction medium under the action of an oxidative cracking agent to obtain a high cis-1,4 hydroxyl-containing epoxidized terminal aldehyde polybutadiene liquid rubber, and the high cis-1,4 hydroxyl-containing epoxidized terminal aldehyde polybutadiene liquid rubber is reduced in the presence of a reaction medium and a reducing agent to obtain a high cis-1,4 hydroxyl-containing epoxidized terminal aldehyde polybutadiene liquid rubber. The high cis-1,4 hydroxyl-containing epoxidized terminal aldehyde polybutadiene liquid rubber has a number average molecular weight of 2000 to 13000 g / mol and an epoxidation degree of 1 to 30%. The preparation process uses a "one-pot method", which has the disadvantages of long reaction time, low selectivity of reaction conditions, and low epoxidation degree of the obtained product. CN107459591A discloses a method for preparing epoxidized medium-high vinyl polybutadiene rubber, wherein the medium-high vinyl polybutadiene rubber is dissolved in an organic solvent under nitrogen protection to obtain a rubber glue, and then the acidified product is mixed with a phase transfer catalyst to obtain a mixture after acidification with an organic carboxylic acid, and then a hydrogen peroxide solution containing tungstate is added dropwise to the mixture for epoxidation. The weight average molecular weight of the epoxidized medium-high vinyl polybutadiene rubber is 1×10 5 ~10×10 5 , epoxidation degree 5 to 25%. The disadvantages of this preparation process are long reaction time, low epoxidation efficiency, low epoxidation degree of the obtained product, and high molecular weight will lead to high viscosity of the gel, which is not conducive to microchannel discharge and mixed rubber dispersion. At present, there are no reports in the literature and patents on the use of epoxidized liquid polybutadiene as a compatibilizer for the volume expansion modification of solution polystyrene butadiene rubber. The prior art has problems such as long reaction time, low condition selectivity, strong heat release, and difficulty in temperature control. In addition, the existing epoxidation modification method for polybutadiene rubber cannot obtain liquid rubber with a higher epoxidation degree. The epoxy group can cooperate well with SSBR and white carbon black in the processing of tread rubber. Therefore, in order to obtain epoxidized liquid polybutadiene with suitable molecular weight, higher epoxidation degree and higher vinyl content, a more efficient preparation method is needed. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art and provide an epoxidized medium-high vinyl liquid polybutadiene rubber and its preparation method and application. The problems of strong heat release, slow and difficult removal, difficult temperature control, long reaction time, etc. of small molecular weight polymers in the initial stage of anion reaction process are solved at the microchannel scale, and formic acid and hydrogen peroxide can be fully contacted with polybutadiene rubber solution at the microchannel scale, significantly improving epoxidation efficiency, achieving continuity, and achieving designable epoxidation value and epoxidation degree.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The invention discloses a preparation method of epoxidized medium-high vinyl liquid polybutadiene. The method comprises the following steps: a butadiene solution is subjected to anionic polymerization reaction with a regulator and an initiator, and then subjected to a capping termination reaction with hydrogen to obtain capped medium-high vinyl liquid polybutadiene. The capped medium-high vinyl liquid polybutadiene is firstly reacted with formic acid and then subjected to an epoxidation modification reaction with hydrogen peroxide to obtain the epoxidized medium-high vinyl liquid polybutadiene.

[0008] Specifically:

[0009] (1) a solution containing butadiene, a regulator, and an initiator are subjected to anionic polymerization reaction in a microchannel reaction unit to obtain a medium-high vinyl polybutadiene solution;

[0010] (2) the medium-high vinyl polybutadiene solution obtained in step (1) is subjected to a capping termination reaction with hydrogen in a static mixing reaction unit 1 to obtain a capped medium-high vinyl liquid polybutadiene;

[0011] (3) The blocked medium-high vinyl liquid polybutadiene obtained in step (2) is reacted with formic acid in a static mixing reaction unit 2, and then reacted with hydrogen peroxide in a static mixing reaction unit 3 for epoxidation modification; finally, alkali washing, desalting, centrifugation, and drying are performed to obtain epoxidized medium-high vinyl liquid polybutadiene.

[0012] The microchannel reaction unit is composed of a microchannel polymerization reactor 1 and a time-delay tube reactor 1 connected in series;

[0013] The static mixing reaction unit 1 is composed of a static mixer 1 and a time-delay tube reactor 2 connected in series;

[0014] The static mixing reaction unit 2 is composed of a static mixer 2 and a time-delay tube reactor 3 connected in series;

[0015] The static mixing reaction unit 3 is composed of a static mixer 3 and a time-delay tube reactor 4 connected in series.

[0016] Furthermore, the preparation method of epoxidized medium-high vinyl liquid polybutadiene includes anionic polymerization reaction, hydrogen end-capping termination reaction and epoxidation reaction, and the specific steps are:

[0017] (1) Anionic polymerization reaction: The initiator and the regulator are mixed and then enter the microchannel reaction unit with the butadiene-containing solution in two ways to carry out anionic polymerization reaction, thereby obtaining a medium-high vinyl polybutadiene solution;

[0018] Alternatively, the solution containing butadiene is mixed with a regulator and then enters the microchannel reaction unit with an initiator in two ways to perform anionic polymerization to obtain a medium-high vinyl polybutadiene solution;

[0019] (2) Hydrogen end-capping and termination reaction: the medium-high vinyl polybutadiene solution obtained in step (1) is subjected to an end-capping and termination reaction with hydrogen in a static mixing reaction unit 1 to obtain an end-capped medium-high vinyl liquid polybutadiene;

[0020] (3) The blocked medium-high vinyl liquid polybutadiene obtained in step (2) is reacted with formic acid in a static mixing reaction unit 2, and then reacted with hydrogen peroxide in a static mixing reaction unit 3 for epoxidation modification; and then alkali washing, desalting, centrifugation, and drying are performed to obtain epoxidized medium-high vinyl liquid polybutadiene.

[0021] In step (1): the microchannel polymerization reactor 1 and the time-delay tube reactor 1 are placed in a cold bath at -80°C to -40°C; the residence time in the microchannel reaction unit is 20 to 55 minutes;

[0022] In step (2): the static mixer 1 and the delay tube reactor 2 are placed in a water bath at 25°C to 65°C; the residence time in the static mixing reaction unit 1 is 10 to 35 minutes;

[0023] In step (3): static mixer 2, delayed tube reactor 3, static mixer 3, and delayed tube reactor 4 are placed in a water bath at 25° C. to 70° C.; the total residence time in static mixing reaction unit 2 and static mixing reaction unit 3 is 30 to 90 min;

[0024] In step (2), the molar ratio of hydrogen to butadiene in the medium-high vinyl polybutadiene is 0.30-0.45:1;

[0025] In step (3), the molar ratio of formic acid to butadiene in the medium-high vinyl polybutadiene solution is 0.05 to 1.20:1; and the molar ratio of hydrogen peroxide to butadiene in the medium-high vinyl polybutadiene is 0.10 to 1.20:1.

[0026] The butadiene-containing solution in step (1) is obtained by dissolving butadiene in a mixed solvent; the mixed solvent is one or more inert solvents selected from alkanes, cycloalkanes and aromatic hydrocarbons, preferably one or more selected from hexane, cyclohexane, benzene, toluene, xylene and the like;

[0027] The initiator in step (1) is one or more of n-butyl lithium, sec-butyl lithium, tert-butyl lithium and isobutyl lithium;

[0028] The regulator in step (1) is one or more of sodium tert-amyl alcohol, ditetrahydrofurfuryl propane, diethylene glycol dimethyl ether and tetramethylethylenediamine.

[0029] The microchannel polymerization reactor 1 is an impinging flow reactor; the delayed tube reactor 1, the delayed tube reactor 2, the delayed tube reactor 3, and the delayed tube reactor 4 are all coil tube reactors;

[0030] Static mixer 1, static mixer 2 and static mixer 3 are all fully mixed tube reactors.

[0031] The molecular weight (Mn) of the medium-high vinyl polybutadiene prepared in step (1) is 3000-12000, the molecular weight distribution is 1.00-1.20, and the content of 1,2-structural units is 50-95% by weight; the epoxidized medium-high vinyl liquid polybutadiene obtained in step (3) has an epoxidation degree of 15%-50%.

[0032] The epoxidized medium-high vinyl liquid polybutadiene prepared by the preparation method is used as a compatibilizer for preparing SSBR vulcanized rubber.

[0033] Compared with the prior art, the beneficial effects of the present disclosure include:

[0034] The epoxidized medium-high vinyl polybutadiene rubber of the present invention is prepared by combining a microchannel polymerization reactor, an epoxidation static mixer and a time-delay tube reactor in series in the presence of an initiator, a regulator, hydrogen, formic acid and hydrogen peroxide. The obtained epoxidized medium-high vinyl polybutadiene rubber can be used as a compatibilizer, has good compatibility with solution-polymerized styrene-butadiene rubber and white carbon black, has stable performance after compounding, and has broad market application and development prospects in the preparation of "green tires".

[0035] The present invention is based on anionic polymerization mode, and completes the entire preparation method through a microchannel reactor, so that the materials are fully contacted and reacted, and the problems of strong heat release, slow and difficult removal, difficult temperature control, and long reaction time of small molecular weight polymers in the initial stage of anionic reaction are solved. The molecular weight (Mn) of the medium-high vinyl liquid polybutadiene rubber prepared by the method of the present invention is 3000-12000, the molecular weight distribution is 1.00-1.20, the content of 1,2-structural units is 50-95% by weight, and the epoxidation degree of the epoxidized medium-high vinyl liquid polybutadiene is 15%-50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a process flow chart of the present invention.

[0037] Figure 2 This is a schematic structural diagram of a microchannel polymerization reactor 1 used in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The specific implementation modes of the present invention are further described below in conjunction with examples. It should be noted that the specific implementation modes described here are only for illustrating and explaining the present invention, and are not limited to the present invention.

[0039] The microchannel polymerization reactor 1 of the present invention is an impinging flow reactor; the delayed tube reactor 1, the delayed tube reactor 2, the delayed tube reactor 3, and the delayed tube reactor 4 are all coil tube reactors; the static mixer 1, the static mixer 2, and the static mixer 3 are all fully mixed tube reactors. The reaction devices of the present invention can all be purchased commercially.

[0040] Example 1

[0041] (1) 120.3 g of refined butadiene was dissolved in a mixed solvent of 880.0 g of n-hexane (528.0 g), cyclohexane (87.8 g) and benzene (264.2 g) (mixing ratio was 6:1:3). 35.5 mL of 1.3 M sec-butyl lithium initiator and 2.3 mL of ditetrahydrofuran (tetrahydrofuran to sec-butyl lithium) (the molar ratio of ditetrahydrofuran to sec-butyl lithium was 0.30:1) were mixed in 50 mL of n-hexane, and the butadiene solution and the initiator and regulator solution were metered into a reactor consisting of a microchannel polymerization reactor 1 and a time-delay tube reactor 1 in series by using a micrometering pump in two ways for reaction. The microchannel polymerization reactor 1 and the time-delay tube reactor 1 were placed in a -50°C cold bath, and the efficient mixing mass transfer and heat transfer of the microchannel were utilized. Characteristics: The initial initiation reaction of small molecule butadiene is carried out in the microchannel polymerization reactor 1, and then enters the delay tube reactor 1 to continue the anionic polymerization reaction; the residence time of the solution in the reactor is 21.4 minutes, and an 11.1wt% vinyl polybutadiene solution (the content of 1,2-structural units is 61.2wt%, the content of 1,4-structural units is 38.8wt%) is obtained, the solution viscosity is 57cps, the molecular weight is 3942, and the distribution is 1.03; the product enters the polymer buffer tank 1.

[0042] (2) The medium-vinyl polybutadiene solution is simultaneously passed through a reactor consisting of a static mixer 1 and a delay tube reactor 2 in series via a metering pump and 0.5 MPa low-pressure hydrogen at 1.2 L / min (the molar ratio of hydrogen to butadiene in the medium-vinyl polybutadiene is 0.30:1) in two routes for end-capping termination reaction. The static mixer 1 and the delay tube reactor 2 are placed in a 35° C. water bath. The residence time in the delay tube reactor 2 is 18.5 min. The product enters the polymer buffer tank 2.

[0043] (3) The blocked medium-vinyl polybutadiene solution and 21.1 mL of formic acid (the molar ratio of formic acid to butadiene in the medium-vinyl polybutadiene is 0.22:1) are metered into a reactor consisting of a static mixer 2 and a time-delay tube reactor 3 in series in two ways through a micro-metering pump, and then 56.5 mL of 30% hydrogen peroxide (the molar ratio of hydrogen peroxide to butadiene in the medium-vinyl polybutadiene is 0.25:1) is metered into a reactor consisting of a static mixer 3 and a time-delay tube reactor 4 in series through a branch line with a micro-metering pump. The epoxidation modification reaction was carried out in the reactor, and the static mixer 2, the delay tube reactor 3, the static mixer 3, and the delay tube reactor 4 were placed in a 35°C water bath. The residence time in the static mixer 2 and the delay tube reactor 3 was 5.0 min, and the residence time in the static mixer 3 and the delay tube reactor 4 was 27.5 min. The product entered the polymer buffer tank 3, and then was alkaline washed with 5wt% sodium hydroxide solution, washed with water for 3 times for desalination, centrifuged, and dried to obtain 115.1g of epoxy degree ( 1 H-NMR test analysis, calculated based on the spectrum) 19.6% of medium-vinyl liquid polybutadiene rubber.

[0044] Example 2

[0045] (1) 122.3 g of refined butadiene was dissolved in a mixed solvent of 881.8 g of n-hexane (617.2 g), cyclohexane (88.3 g) and benzene (176.3 g) (mixing ratio was 7:1:2). 19.5 mL of 1.3 M sec-butyl lithium initiator and 4.2 mL of ditetrahydrofuran (tetrahydrofuran to sec-butyl lithium) (the molar ratio of ditetrahydrofuran to sec-butyl lithium was 1.10:1) were mixed in 65 mL of n-hexane, and the butadiene solution and the initiator and regulator solution were metered into a reactor consisting of a microchannel polymerization reactor 1 and a time-delay tube reactor 1 in series by using a micrometering pump in two ways for reaction. The microchannel polymerization reactor 1 and the time-delay tube reactor 1 were placed in a -60°C cold bath, and the efficient mixing mass transfer and heat transfer of the microchannel were utilized. Characteristics: The initial initiation reaction of small molecule butadiene is carried out in the microchannel polymerization reactor 1, and then enters the delay tube reactor 1 to continue the anionic polymerization reaction; the residence time of the solution in the reactor is 34.5 minutes, and a 10.9wt% high vinyl polybutadiene solution (the content of 1,2-structural units is 79.5wt%, the content of 1,4-structural units is 20.5wt%) is obtained, the solution viscosity is 78cps, the molecular weight is 7115, and the distribution is 1.05; the product enters the polymer buffer tank 1.

[0046] (2) The high vinyl polybutadiene solution is simultaneously passed through a reactor consisting of a static mixer 1 and a delay tube reactor 2 in series via a metering pump and 0.5 MPa low-pressure hydrogen at 1.5 L / min (the molar ratio of hydrogen to butadiene in the high vinyl polybutadiene is 0.36:1) in two routes for end-capping termination reaction. The static mixer 1 and the delay tube reactor 2 are placed in a 35°C water bath. The residence time in the delay tube reactor 2 is 20.6 min. The product enters the polymer buffer tank 2.

[0047] (3) The blocked high vinyl polybutadiene solution and 38.4 mL of formic acid (the molar ratio of formic acid to butadiene in the high vinyl polybutadiene is 0.40:1) are metered into a reactor consisting of a static mixer 2 and a delay tube reactor 3 in series in two ways through a micro-metering pump, and then 105.2 mL of 30% hydrogen peroxide (the molar ratio of hydrogen peroxide to butadiene in the high vinyl polybutadiene is 0.45:1) is metered into a reactor consisting of a static mixer 3 and a delay tube reactor 4 in series through a branch line with a micro-metering pump. The epoxidation modification reaction was carried out in the reactor, the static mixer 2, the delay tube reactor 3, the static mixer 3, and the delay tube reactor 4 were placed in a 45°C water bath, the residence time in the static mixer 2 and the delay tube reactor 3 was 8.0 min, the residence time in the static mixer 3 and the delay tube reactor 4 was 34.5 min, the product entered the polymer buffer tank 3, and then was washed with 5wt% sodium hydroxide solution, washed with water for desalination for 3 times, centrifuged, and dried to obtain 117.4g of epoxy degree ( 1 H-NMR test analysis, calculated based on the spectrum) 35.4% high vinyl liquid polybutadiene rubber.

[0048] Example 3

[0049] (1) 125.6 g of refined butadiene was dissolved in a mixed solvent of 886.5 g of n-hexane (620.5 g), cyclohexane (88.5 g) and toluene (177.5 g) (mixing ratio was 7:1:2). 15.5 mL of 1.3 M sec-butyl lithium initiator was dissolved in 70 mL of n-hexane, 4.5 mL of ditetrahydrofurfuryl propane (the molar ratio of ditetrahydrofurfuryl propane to sec-butyl lithium was 1.70:1) and 3.5 mL of diethylene glycol dimethyl ether (the molar ratio of diethylene glycol dimethyl ether to sec-butyl lithium was 1.80:1) were mixed in the butadiene solution, and a micrometering pump was used to meter the mixed solution of the butadiene solution and the regulator and the initiator into a reactor composed of a microchannel polymerization reactor 1 and a time-delayed tube reactor 1 in series for reaction. The microchannel polymerization reactor 1 and the time-delayed tube reactor 1 were placed in a reactor. In a -70°C cold bath, the microchannel's efficient mixed mass transfer and heat transfer characteristics are utilized to carry out the initial initiation reaction of small molecule butadiene in the microchannel polymerization reactor 1, and then the solution enters the delay tube reactor 1 to continue the anionic polymerization reaction; the residence time of the solution in the reactor is 44.5 minutes, and an 11.3wt% high vinyl polybutadiene solution (the content of 1,2-structural units is 90.3wt%, and the content of 1,4-structural units is 9.7wt%) is obtained, the solution viscosity is 125cps, the molecular weight is 10247, and the distribution is 1.05; the product enters the polymer buffer tank 1.

[0050] (2) The high vinyl polybutadiene solution is simultaneously passed through a reactor consisting of a static mixer 1 and a delay tube reactor 2 in series through a metering pump and 0.5 MPa low-pressure hydrogen at 1.8 L / min (the molar ratio of hydrogen to butadiene in the high vinyl polybutadiene is 0.45:1) to perform a capping termination reaction. The static mixer 1 and the delay tube reactor 2 are placed in a 35°C water bath. The residence time in the delay tube reactor 2 is 28.5 min; and then the solution enters the polymer buffer tank 2.

[0051] (3) The blocked high vinyl polybutadiene solution and 39.1 mL of formic acid (the molar ratio of formic acid to butadiene in the high vinyl polybutadiene is 0.40:1) are metered into a reactor consisting of a static mixer 2 and a delay tube reactor 3 in series in two ways through a micro-metering pump, and then 106.0 mL of 30% hydrogen peroxide (the molar ratio of hydrogen peroxide to butadiene in the high vinyl polybutadiene is 0.45:1) is metered into a reactor consisting of a static mixer 3 and a delay tube reactor 4 in series through a branch line with a micro-metering pump. The epoxidation modification reaction was carried out in the reactor, the static mixer 2, the delay tube reactor 3, the static mixer 3, and the delay tube reactor 4 were placed in a 45°C water bath, the residence time in the static mixer 2 and the delay tube reactor 3 was 8.0 min, the residence time in the static mixer 3 and the delay tube reactor 4 was 40.5 min, the product entered the polymer buffer tank 3, and then was washed with 5wt% sodium hydroxide solution, washed with water for 3 times for desalination, centrifuged, and dried to obtain 119.3g of epoxy degree (1 H-NMR test analysis, calculated based on the spectrum) 37.8% of high vinyl liquid polybutadiene rubber.

[0052] Example 4

[0053] (1) 118.5 g of refined butadiene was dissolved in a mixed solvent of 876.6 g of n-hexane (526.2 g), cyclohexane (89.6 g) and benzene (260.8 g) (mixing ratio was 6:1:3). 38.5 mL of 1.6 M n-butyl lithium initiator was dissolved in 50 mL of n-hexane, 14.2 mL of 1.4 M sodium tert-amyl alcoholate solution (the molar ratio of sodium tert-amyl alcoholate to n-butyl lithium was 0.50:1) and 2.8 mL of diethylene glycol dimethyl ether (the molar ratio of diethylene glycol dimethyl ether to n-butyl lithium was 0.50:1) were mixed in the butadiene solution, and a micro-metering pump was used to meter the mixed solution of the butadiene solution and the regulator and the initiator into a reactor composed of a microchannel polymerization reactor 1 and a delay tube reactor 1 connected in series for reaction. The microchannel polymerization reactor 1 and The delayed tube reactor 1 is placed in a -50°C cold bath, and the high-efficiency mixed mass transfer and heat transfer of the microchannel are used to carry out the initial initiation reaction of small molecule butadiene, and then enters the delayed tube reactor 1 to continue the anionic polymerization reaction; the residence time of the solution in the reactor is 23.5 minutes, and a 10.8wt% vinyl polybutadiene solution (the content of 1,2-structural units is 60.1wt%, and the content of 1,4-structural units is 39.9wt%) is obtained, the solution viscosity is 51cps, the molecular weight is 3359, and the distribution is 1.03; the product enters the polymer buffer tank 1.

[0054] (2) The medium-vinyl polybutadiene solution is simultaneously passed through a reactor consisting of a static mixer 1 and a delay tube reactor 2 in series through a metering pump and 0.5 MPa low-pressure hydrogen at 1.2 L / min (the molar ratio of hydrogen to butadiene in the medium-vinyl polybutadiene is 0.30:1) to perform a capping termination reaction. The static mixer 1 and the delay tube reactor 2 are placed in a 35°C water bath. The residence time in the delay tube reactor 2 is 17.2 min; the product enters the polymer buffer tank 2.

[0055] (3) The blocked medium-vinyl polybutadiene solution and 34.5 mL of formic acid (the molar ratio of formic acid to butadiene in the medium-vinyl polybutadiene is 0.36:1) are metered into a reactor consisting of a static mixer 2 and a delay tube reactor 3 in series by two ways through a micro-metering pump, and then 56.5 mL of 30% hydrogen peroxide (the molar ratio of hydrogen peroxide to butadiene in the medium-vinyl polybutadiene is 0.25:1) is metered into a reactor consisting of a static mixer 3 and a delay tube reactor 4 in series by a branch through a micro-metering pump. The epoxidation modification reaction was carried out in the reactor, and the static mixer 2, the delay tube reactor 3, the static mixer 3, and the delay tube reactor 4 were placed in a 35°C water bath. The residence time in the static mixer 2 and the delay tube reactor 3 was 6.5 min, and the residence time in the static mixer 3 and the delay tube reactor 4 was 24.5 min. The product entered the polymer buffer tank 3, and then was alkaline washed with 5wt% sodium hydroxide solution, washed with water for 3 times for desalination, centrifuged, and dried to obtain 111.7g of epoxy degree ( 1 H-NMR test analysis, calculated based on the spectrum) 21.8% of medium-vinyl liquid polybutadiene rubber.

[0056] Example 5

[0057] (1) 122.4 g of refined butadiene was dissolved in a mixed solvent of 880.8 g of n-hexane (618.5 g), cyclohexane (86.4 g) and toluene (175.9 g) (mixing ratio was 7:1:2). 26.0 mL of 1.6 M n-butyl lithium initiator was dissolved in 62 mL of n-hexane, 14.3 mL of 1.4 M sodium tert-amyl alcoholate solution (the molar ratio of sodium tert-amyl alcoholate to n-butyl lithium was 1.00:1) and 3.0 mL of tetramethylethylenediamine (the molar ratio of tetramethylethylenediamine to n-butyl lithium was 1.00:1) were mixed in the butadiene solution, and a micrometering pump was used to meter the mixed solution of the butadiene solution and the regulator and the initiator into a reactor composed of a microchannel polymerization reactor 1 and a delay tube reactor 1 in series for reaction. The microchannel polymerization reactor 1 and the delay tube reactor 1 were connected in series to form a reactor. The time-delayed tube reactor 1 is placed in a -60°C cold bath, and the microchannel's efficient mixed mass transfer and heat transfer are used to carry out the initial initiation reaction of small molecule butadiene, and then enters the delayed tube reactor 1 to continue the anionic polymerization reaction; the residence time of the solution in the reactor is 32.2 minutes, and an 11.0wt% high vinyl polybutadiene solution (the content of 1,2-structural units is 86.2% by weight, and the content of 1,4-structural units is 13.8% by weight) is obtained, the solution viscosity is 75cps, the molecular weight is 6842, and the distribution is 1.04; the product enters the polymer buffer tank 1.

[0058] (2) The high vinyl polybutadiene solution is simultaneously passed through a reactor consisting of a static mixer 1 and a delay tube reactor 2 in series via a metering pump and 0.5 MPa low-pressure hydrogen at 1.5 L / min (the molar ratio of hydrogen to butadiene in the high vinyl polybutadiene is 0.36:1) in two routes for end-capping termination reaction. The static mixer 1 and the delay tube reactor 2 are placed in a 35°C water bath. The residence time in the delay tube reactor 2 is 23.6 min. The product enters the polymer buffer tank 2.

[0059] (3) The blocked high vinyl polybutadiene solution and 52.0 mL of formic acid (the molar ratio of formic acid to butadiene in the high vinyl polybutadiene is 0.65:1) are metered into a reactor consisting of a static mixer 2 and a delay tube reactor 3 in series by a micro-metering pump in two ways, and then 113.3 mL of 30% hydrogen peroxide (the molar ratio of hydrogen peroxide to butadiene in the high vinyl polybutadiene is 0.50:1) is metered into a reactor consisting of a static mixer 3 and a delay tube reactor 4 in series by a micro-metering pump through a branch. The epoxidation modification reaction was carried out in the reactor, and the static mixer 2, the delay tube reactor 3, the static mixer 3, and the delay tube reactor 4 were placed in a 45°C water bath. The residence time in the static mixer 2 and the delay tube reactor 3 was 12.0 min, and the residence time in the static mixer 3 and the delay tube reactor 4 was 33.0 min. The product entered the polymer buffer tank 3, and then was washed with 5wt% sodium hydroxide solution, washed with water for desalination for 3 times, centrifuged, and dried to obtain 115.6g of epoxy degree ( 1 H-NMR test analysis, calculated based on the spectrum) 32.5% high vinyl liquid polybutadiene rubber.

[0060] Example 6

[0061] (1) 127.2 g of refined butadiene was dissolved in a mixed solvent of 890.1 g of n-hexane (444.0 g), cyclohexane (180.9 g) and toluene (265.2 g) (mixing ratio was 5:2:3). 16.2 mL of 1.6 M n-butyl lithium initiator was dissolved in 70 mL of n-hexane, 3.9 mL of ditetrahydrofurfuryl propane (the molar ratio of ditetrahydrofurfuryl propane to sec-butyl lithium was 1.50:1), 1.9 mL of diethylene glycol dimethyl ether (the molar ratio of diethylene glycol dimethyl ether to n-butyl lithium was 1.00:1), and 2.0 mL of tetramethylethylenediamine (the molar ratio of tetramethylethylenediamine to n-butyl lithium was 1.00:1) were mixed in the butadiene solution, and a micrometering pump was used to meter the mixed solution of the butadiene solution and the regulator and the initiator into a reactor consisting of a microchannel polymerization reactor 1 and a delay tube reactor 1 connected in series. The reaction is carried out in the microchannel polymerization reactor 1 and the delay tube reactor 1 are placed in a -70°C cold bath, and the initial initiation reaction of small molecule butadiene is carried out by utilizing the efficient mixed mass transfer and heat transfer of the microchannel, and then the solution enters the delay tube reactor 1 to continue the anionic polymerization reaction; the residence time of the solution in the reactor is 42.5 minutes, and an 11.3wt% high vinyl polybutadiene solution (the content of 1,2-structural units is 92.4wt%, and the content of 1,4-structural units is 7.6wt%) is obtained, the solution viscosity is 119cps, the molecular weight is 9922, and the distribution is 1.05; the product enters the polymer buffer tank 1.

[0062] (2) The high vinyl polybutadiene solution is simultaneously passed through a reactor consisting of a static mixer 1 and a delay tube reactor 2 in series via a metering pump and 0.5 MPa low-pressure hydrogen at 1.8 L / min (the molar ratio of hydrogen to butadiene in the high vinyl polybutadiene is 0.45:1) in two routes for end-capping termination reaction. The static mixer 1 and the delay tube reactor 2 are placed in a 35°C water bath. The residence time in the delay tube reactor 2 is 26.4 min. The product enters the polymer buffer tank 2.

[0063] (3) The blocked high vinyl polybutadiene solution and 56.6 mL of formic acid (the molar ratio of formic acid to butadiene in the high vinyl polybutadiene is 0.70:1) are metered into a reactor consisting of a static mixer 2 and a delay tube reactor 3 in series by a micro-metering pump in two ways, and then 133.0 mL of 30% hydrogen peroxide (the molar ratio of hydrogen peroxide to butadiene in the high vinyl polybutadiene is 0.70:1) is metered into a reactor consisting of a static mixer 3 and a delay tube reactor 4 in series by a micro-metering pump through a branch. The epoxidation modification reaction was carried out in the reactor. The static mixer 2, the delay tube reactor 3, the static mixer 3 and the delay tube reactor 4 were placed in a 45°C water bath. The residence time in the static mixer 2 and the delay tube reactor 3 was 13.5 min, and the residence time in the static mixer 3 and the delay tube reactor 4 was 48.3 min. The product entered the polymer buffer tank 3, and then was washed with 5wt% sodium hydroxide solution, washed with water for 3 times for desalination, centrifuged and dried to obtain 120.8g of epoxy degree ( 1 H-NMR test analysis, calculated based on the spectrum) 49.7% of high vinyl liquid polybutadiene rubber.

[0064] Comparative Example 1

[0065] The difference between Comparative Example 1 and Example 2 is that the microchannel polymerization reactor 1 in Example 2 is replaced by a conventional impinging flow microchannel reactor, and the other steps are the same as those in Example 2 to obtain a low vinyl polybutadiene solution (the content of 1,2-structural units is 37.2% by weight, the content of 1,4-structural units is 62.8% by weight), the solution viscosity is 82cps, the molecular weight is 7575, and the distribution is 1.12; after epoxidation modification reaction, an epoxidation degree ( 1 H-NMR test analysis, calculated based on the spectrum) 25.4% low vinyl liquid polybutadiene rubber.

[0066] Comparative Example 2

[0067] The difference between Comparative Example 2 and Example 6 is that the steps of anionic polymerization reaction and end-capping termination reaction are the same as those in Example 6, and a high vinyl polybutadiene solution (the content of 1,2-structural units is 91.8% by weight, and the content of 1,4-structural units is 8.2% by weight) is obtained, the solution viscosity is 123 cps, the molecular weight is 9950, and the distribution is 1.05; when performing the epoxidation modification reaction, the static mixer 2, the time-delay tube reactor 3, the static mixer 3, and the time-delay tube reactor 4 are placed in a 20° C. water bath, and the other steps are the same as those in Example 6, and an epoxidation degree ( 1 H-NMR test analysis, calculated based on the spectrum) 4.6% high vinyl liquid polybutadiene rubber.

[0068] Comparative Example 3

[0069] The difference between Comparative Example 3 and Example 6 is that the steps of anionic polymerization reaction and end-capping termination reaction are the same as those in Example 6, and a high vinyl polybutadiene solution (the content of 1,2-structural units is 92.1% by weight, the content of 1,4-structural units is 7.9% by weight) is obtained, the solution viscosity is 117 cps, the molecular weight is 9919, and the distribution is 1.05; when the epoxidation modification reaction is carried out, the residence time in the static mixer 2 and the delayed tube reactor 3 is 3.5 min, and the residence time in the static mixer 3 and the delayed tube reactor 4 is 8.0 min, and the other steps are the same as those in Example 6, and an epoxidation degree ( 1 H-NMR test analysis, calculated based on the spectrum) 3.5% high vinyl liquid polybutadiene rubber.

[0070] Rubber processing conditions

[0071] Formula and vulcanization conditions:

[0072] formula:

[0073] Examples 1 to 6 and Comparative Examples 1 to 3 were used as compatibilizers to prepare SSBR vulcanizates: 100 parts of SSBR; 60 parts of carbon black N234; 4 parts of zinc oxide; 2 parts of stearic acid; 1.8 parts of accelerator; 1.8 parts of sulfur; 2.5 parts of antioxidant; 5 parts of liquid resin; 3 parts of homogenizer; and 2 parts of compatibilizer.

[0074] Comparative Example 4: 100 parts of SSBR; 60 parts of carbon black N234; 4 parts of zinc oxide; 2 parts of stearic acid; 1.8 parts of accelerator; 1.8 parts of sulfur; 2.5 parts of antioxidant; 5 parts of liquid resin; 3 parts of homogenizer; 2 parts of commercially available polymer rubber type compatibilizer MLPB-1 (Beijing Yanshan Jilian Petrochemical Company).

[0075] Curing conditions: 150℃×(t 90 +3)min.

[0076] Performance Characterization

[0077] The vulcanization performance and mechanical properties of SSBR vulcanizate are tested according to relevant national standards.

[0078] Dynamic compression fatigue performance of SSBR vulcanized rubber: A compression fatigue testing machine was used with test conditions of room temperature to 50°C, preheating for 20 minutes, dynamic compression time for 20 minutes, compression frequency of 1800 times / min, stroke of 6 mm, and the specimen bearing a load of 1.0 MPa.

[0079] Mechanical properties of SSBR vulcanizate: electronic universal testing machine was used, and the test conditions were temperature 25℃ and tensile speed 500mm / min.

[0080] The performance test results of SSBR vulcanizate are shown in Table 1.

[0081] Table 1 Performance test results of SSBR vulcanizate

[0082]

[0083] As can be seen from Table 1, under the same addition amount, the tensile strength, 300% tensile stress and tear strength of the SSBR vulcanized rubber prepared by the liquid polybutadiene rubber with higher vinyl content and higher epoxidation degree as a compatibilizer in the embodiment of the present invention are higher, and the compression fatigue temperature rise is low, so that the reinforcing effect of carbon black is better played, and the strength of the vulcanized rubber is increased and more fatigue-resistant. The ratio of 300% tensile stress to 100% tensile stress can characterize the ease of sliding of the macromolecular chain along the surface of the carbon black filler. The larger the ratio, the greater the interaction between the polymer and the filler. The higher the epoxidation degree of the liquid polybutadiene rubber compatibilizer added, the larger the ratio. Therefore, the epoxidized high vinyl liquid polybutadiene of the present invention acts as a compatibilizer in SSBR to play a bonding role, which is beneficial to the dispersion of carbon black, enhances the interaction between rubber and carbon black, thereby weakening the internal friction and reducing heat generation. In addition, the good dispersion of carbon black can organize carbon black particles to form a carbon black network in the vulcanized rubber, so that the hysteresis loss caused by carbon black aggregation is reduced. From the overall embodiment, the high-vinyl liquid polybutadiene compatibilizer is better than the medium-vinyl liquid polybutadiene compatibilizer; at the same time, compared with the commercially available compatibilizer added in the control example, the strength, toughness and fatigue resistance of the vulcanized rubber of the homemade compatibilizer are better than the SSBR vulcanized rubber added with the commercially available compatibilizer.

Claims

1. A method for preparing epoxidized medium-high vinyl liquid polybutadiene, characterized in that After the butadiene solution undergoes anionic polymerization reaction with a regulator and an initiator, it is then subjected to a capping termination reaction with hydrogen to obtain a capped medium-high vinyl liquid polybutadiene. The capped medium-high vinyl liquid polybutadiene is first reacted with formic acid and then subjected to an epoxidation modification reaction with hydrogen peroxide to obtain an epoxidized medium-high vinyl liquid polybutadiene.

2. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , (1) a solution containing butadiene, a regulator, and an initiator are subjected to anionic polymerization reaction in a microchannel reaction unit to obtain a medium-high vinyl polybutadiene solution; (2) the medium-high vinyl polybutadiene solution obtained in step (1) is subjected to a capping termination reaction with hydrogen in a static mixing reaction unit 1 to obtain a capped medium-high vinyl liquid polybutadiene; (3) The blocked medium-high vinyl liquid polybutadiene obtained in step (2) is reacted with formic acid in a static mixing reaction unit 2, and then reacted with hydrogen peroxide in a static mixing reaction unit 3 for epoxidation modification; finally, alkali washing, desalting, centrifugation, and drying are performed to obtain epoxidized medium-high vinyl liquid polybutadiene.

3. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , The microchannel reaction unit is composed of a microchannel polymerization reactor 1 and a time-delay tube reactor 1 connected in series; The static mixing reaction unit 1 is composed of a static mixer 1 and a time-delay tube reactor 2 connected in series; The static mixing reaction unit 2 is composed of a static mixer 2 and a time-delay tube reactor 3 connected in series; The static mixing reaction unit 3 is composed of a static mixer 3 and a time-delay tube reactor 4 connected in series.

4. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , including anionic polymerization reaction, hydrogen termination reaction and epoxidation reaction, the specific steps are: (1) Anionic polymerization reaction: The initiator and the regulator are mixed and then enter the microchannel reaction unit with the butadiene-containing solution in two ways to carry out anionic polymerization reaction, thereby obtaining a medium-high vinyl polybutadiene solution; Alternatively, the solution containing butadiene is mixed with a regulator and then enters the microchannel reaction unit with an initiator in two ways to perform anionic polymerization to obtain a medium-high vinyl polybutadiene solution; (2) Hydrogen end-capping and termination reaction: the medium-high vinyl polybutadiene solution obtained in step (1) is subjected to an end-capping and termination reaction with hydrogen in a static mixing reaction unit 1 to obtain an end-capped medium-high vinyl liquid polybutadiene; (3) The blocked medium-high vinyl liquid polybutadiene obtained in step (2) is reacted with formic acid in a static mixing reaction unit 2, and then reacted with hydrogen peroxide in a static mixing reaction unit 3 for epoxidation modification; and then alkali washing, desalting, centrifugation, and drying are performed to obtain epoxidized medium-high vinyl liquid polybutadiene.

5. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , In step (1): the microchannel polymerization reactor 1 and the time-delay tube reactor 1 are placed in a cold bath at -80°C to -40°C; the residence time in the microchannel reaction unit is 20 to 55 minutes; In step (2): the static mixer 1 and the delay tube reactor 2 are placed in a water bath at 25°C to 65°C; the residence time in the static mixing reaction unit 1 is 10 to 35 minutes; In step (3): static mixer 2, delayed tube reactor 3, static mixer 3, delayed tube reactor 4 are placed in a water bath at 25°C to 70°C; the total residence time in static mixing reaction unit 2 and static mixing reaction unit 3 is 30 to 90 minutes.

6. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , In step (2), the molar ratio of hydrogen to butadiene in the medium-high vinyl polybutadiene is 0.30 to 0.45:1; In step (3), the molar ratio of formic acid to butadiene in the medium-high vinyl polybutadiene solution is 0.05 to 1.20:1; and the molar ratio of hydrogen peroxide to butadiene in the medium-high vinyl polybutadiene is 0.10 to 1.20:

1.

7. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , The butadiene-containing solution in step (1) is obtained by dissolving butadiene in a mixed solvent; the mixed solvent is one or more inert solvents selected from alkanes, cycloalkanes and aromatic hydrocarbons, preferably one or more selected from hexane, cyclohexane, benzene, toluene, xylene and the like; The initiator in step (1) is one or more of n-butyl lithium, sec-butyl lithium, tert-butyl lithium and isobutyl lithium; The regulator in step (1) is one or more of sodium tert-amyl alcohol, ditetrahydrofurfuryl propane, diethylene glycol dimethyl ether and tetramethylethylenediamine.

8. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 1, characterized in that , The microchannel polymerization reactor 1 is an impinging flow reactor; the delayed tube reactor 1, the delayed tube reactor 2, the delayed tube reactor 3, and the delayed tube reactor 4 are all coil tube reactors; Static mixer 1, static mixer 2 and static mixer 3 are all fully mixed tube reactors.

9. The method for preparing epoxidized medium-high vinyl liquid polybutadiene according to claim 2, characterized in that The molecular weight (Mn) of the medium-high vinyl polybutadiene prepared in step (1) is 3000-12000, the molecular weight distribution is 1.00-1.20, and the content of 1,2-structural units is 50-95% by weight; the epoxidized medium-high vinyl liquid polybutadiene obtained in step (3) has an epoxidation degree of 15%-50%.

10. An epoxidized medium-high vinyl liquid polybutadiene prepared by the preparation method according to claim 1 is used as a compatibilizer to prepare SSBR vulcanizate.

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