CN116987219A - Process for continuous polymerization of conjugated diolefins - Google Patents

Abstract

The invention relates to the field of rubber, and discloses a continuous polymerization method of conjugated diene, which comprises the following steps: 1) In the presence of a first organic solvent, carrying out first mixing on the component A and the component E, and then carrying out first aging to obtain a first mixture; performing second aging after performing second mixing on the first mixture, the component D and the component B to obtain a second mixture; thirdly, mixing the second mixture with the component C for the third time to obtain a third mixture; fourth aging is carried out on the third mixture to obtain a rare earth catalyst; 2) Under the polymerization reaction condition, the conjugated diene and the rare earth catalyst are continuously fed into a polymerization unit to be contacted with an organic solvent. According to the method, the catalyst preparation process and the polymerization process are continuously integrated, so that the production efficiency is improved, the labor intensity is reduced, the operation cost is reduced, the automatic production is easy to realize, and the polymerization product with stable performance is obtained, and has great industrial application prospect.

Description

Method for continuous polymerization of conjugated dienes

Technical field

The present invention relates to the field of rubber, and in particular, to a method for continuous polymerization of conjugated dienes.

Background technique

Compared with lithium-based, nickel-based, titanium-based, and cobalt-based butadiene rubber, butadiene rubber prepared using rare earth catalysts has the highest cis structure and the lowest vinyl unit, and the degree of branching is very small, making the macromolecular chain have The high regularity and perfect linear structure give rare earth butadiene rubber high strength, high wear resistance and good dynamic mechanical properties to ensure the development needs of tires made from it in terms of high speed, energy saving, safety and environmental protection. Especially suitable for tread rubber and sidewall rubber. Therefore, rare earth butadiene rubber is considered to be the most promising type of butadiene rubber.

At present, all methods for preparing rare earth catalysts adopt intermittent aging. For example, CN101045768A discloses a rare earth catalyst and its preparation method, and specifically discloses that the preparation method of the catalyst includes sequentially adding a rare earth organic compound, a conjugated diene and an alkyl aluminum into an aging container, and reacting for 1-10 minutes. Then, add chloride and continue the reaction for 5 minutes to 24 hours. Michelin disclosed a synthetic polyisoprene and its preparation method in CN1479754A. The rare earth catalyst used is composed of conjugated diene/rare earth phosphate/alkylaluminum/halide. The preparation method is relatively complicated. It is divided into seven stages, each stage has strict requirements on temperature and time, and the final prepared catalyst needs to be stored at -15°C. However, the use of intermittent aging to prepare catalysts will cause fluctuations in the performance of the polymerization product. This is because although each batch of catalysts is prepared according to certain conditions, it is difficult to control them exactly the same, thus affecting the performance of the resulting catalyst. Differences also exist and lead to large fluctuations in the properties of the resulting polymer.

Contents of the invention

The object of the present invention is to provide a new method for the continuous polymerization of conjugated dienes, which continuously integrates the catalyst preparation process and the polymerization process, thereby not only improving production efficiency, reducing labor intensity, and reducing operating costs, but also It is also easy to realize automated production and obtain polymer products with stable performance, which has great industrial application prospects.

In order to achieve the above object, the present invention provides a method for continuous polymerization of conjugated dienes, which is characterized in that the method includes the following steps:

1) In the presence of the first organic solvent, component A and component E are respectively sent to the first mixing unit for the first mixing, then enter the first coil for the first aging, and then enter the first In the buffer unit, the first mixture is obtained; the first mixture, component D and component B are sent to the second mixing unit respectively for the second mixing, and then enter the second coil for the second aging, Then it enters the second buffer unit to obtain the second mixture; the second mixture and component C are sent to the third mixing unit respectively for the third mixing, and then enter the third coil for the third aging. , and then enters the third buffer unit to obtain the third mixture; the third mixture is sent to the fourth coil for the fourth aging to obtain the rare earth catalyst;

2) Under polymerization reaction conditions, continuously feed the conjugated diene, the rare earth catalyst obtained in step 1) and the second organic solvent into the polymerization unit for contact,

Among them, component A is a neodymium phosphonate compound represented by formula (1); component B is an alkyl aluminum compound; component C is a halogenated compound; component D is a conjugated diene; component E is Compounds represented by formula (2),

In formula (1), R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are each independently a hydroxyl group, a C1-C20 alkyl group or a C1-C20 alkoxy group;

In formula (2), R ^d1 , R ^d2 and R ^d3 are each independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group.

Preferably, the conditions for the first mixing include: the temperature is 10-60°C, preferably 30-50°C.

Preferably, the conditions for the first aging include: the temperature is 10-60°C, the residence time in the first coil is 2-60h, preferably 5-10h, and the linear speed in the first coil is 0.1-50cm/min, preferably 0.3-0.5cm/min.

Preferably, the second mixing conditions include: the temperature is 0-50°C, preferably 20-40°C.

Preferably, the second aging conditions include: the temperature is 0-50°C, the residence time in the second coil is 5-120min, preferably 20-45min, and the linear speed in the second coil is 0.1-50cm/min, preferably 0.6-1cm/min.

Preferably, the third mixing condition includes: the temperature is 10-80°C, preferably 50-70°C.

Preferably, the third aging conditions include: the temperature is 10-80°C, the residence time in the third coil is 30-180min, preferably 90-150min, and the linear speed in the third coil is 0.1-50cm/min, preferably 0.7-1.5cm/min.

Preferably, the conditions for the fourth aging include: the temperature is 0-40°C, the residence time in the fourth coil is 1-48 hours, preferably 12-24 hours, and the line in the fourth coil is The speed is 0.1-50cm/min, preferably 0.7-1.5cm/min.

Preferably, the first mixing unit, the second mixing unit and the third mixing unit are static mixers.

Preferably, the first buffer unit, the second buffer unit and the third buffer unit are buffer tanks.

Preferably, the molar ratio of component A and component E is 1:0.2-0.4.

Preferably, the molar ratio of component A and component B is 1:12-30.

Preferably, the molar ratio of component A and component C is 1:2-5.

Preferably, the molar ratio of component A and component D is 1:10-80.

Preferably, in formula (1), R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are each independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group, preferably a hydroxyl group , n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, 2-ethylpentyl, n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyl Oxygen, 2-methylpentyloxy, 2-ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-ethylhexyloxy, n-heptyloxy, n-octyloxy, n-hexyloxy Nonyloxy, n-decyloxy, n-undecyloxy or n-dodecyloxy.

In formula (2), R ^d1 , R ^d2 and R ^d3 are each independently hydroxyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, 2-ethyl Pentyl, n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-butoxy base, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, 2-methylpentyloxy, 2-ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-Ethylhexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy or n-dodecyloxy.

Preferably, the neodymium phosphonate compound represented by formula (1) is one or more of the following compounds,

R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are compounds of 2-ethylhexyloxy,

R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are compounds of 2-ethylhexyl,

A compound in which R ^a1 , R ^b1 and R ^c1 are 2-ethylhexyl and R ^a2 , R ^b2 and R ^c2 are 2-ethylhexyloxy.

Preferably, the compound represented by formula (2) is di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester and di-(2-ethylhexyl)phosphonic acid. of one or more.

Preferably, the alkyl aluminum compound is selected from trialkyl aluminum and/or dialkylaluminum hydride.

Preferably, the alkyl aluminum compound is trimethylaluminum, triethylaluminum, tripropylaluminum, tributyl aluminum, tripentyl aluminum, trihexyl aluminum, triisobutylaluminum, diethyl aluminum One or more of aluminum hydride, dipropylaluminum hydride, dibutylaluminum hydride and diisobutylaluminum hydride.

The halogenated compounds are diethyl aluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, monochlorosilane, dichlorosilane, trichlorosilane and One or more types of silicon tetrachloride.

Preferably, the conjugated dienes are butadiene, isoprene, piperylene, 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene and 2,3 - one or more dimethylbutadienes.

Preferably, the first organic solvent is one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes;

Preferably, the amount of the first organic solvent is such that the concentration of the rare earth catalyst is 1×10 ^-4 -1 mol/L based on the neodymium phosphonate compound represented by formula (1).

Preferably, the rare earth catalyst is used in an amount such that the amount of component A is 20-200 μmol relative to 1 mol of component D.

Preferably, the second organic solvent is one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes.

Preferably, based on 100 parts by weight of conjugated diene, the amount of the second organic solvent is 400-900 parts by weight.

Preferably, in step 2), the polymerization unit includes at least 2 polymerization reactors in series, preferably 3-10 polymerization reactors in series, and more preferably 3-5 polymerization reactors in series.

Preferably, according to the flow direction of the materials, the fourth coil is connected in series with the first polymerization reactor, so that the rare earth catalyst obtained in step 1) is directly sent to the polymerization unit.

Preferably, in step 2), the polymerization reaction conditions include: the temperature in each polymerization reactor is independently -30°C to 80°C, preferably 0-70°C, more preferably 10-60°C; The contact time in each polymerization reaction kettle is independently 10-90min, preferably 20-80min, more preferably 30-60min; the total contact time in each polymerization reaction kettle does not exceed 300min, preferably 90-180min, More preferably, it is 110-150min.

The inventor of the present invention discovered that in the industrial production of conjugated diene polymers, an intermittent process is used to prepare the catalyst, and the prepared catalyst needs to be stored in a catalyst storage tank and used for a period of time before it is used up. During this period of time, reactions will still occur between the various components of the catalyst, causing its properties to change, resulting in the molecular weight and molecular weight of the polymer products produced at different times during the continuous polymerization process to produce conjugated diene polymers. Its distribution is always changing. These polymers with different molecular weights and distributions are mixed in a glue tank or a coagulation kettle. The final product is actually a mixture, showing a wider molecular weight distribution. However, the wider molecular weight distribution of the polymer will cause the vulcanization network of the vulcanized rubber to be looser, and the density of the elastic effective part in the network will decrease, thereby reducing the physical and mechanical properties of the vulcanized rubber and limiting its application. In addition, the use of intermittent aging to prepare catalysts brings many inconveniences to production, such as the need for multiple catalyst preparations, high labor intensity, high control costs, long non-productive operation times, and large material losses. Large and so on.

The present invention cleverly combines a mixing unit (preferably a static mixer) and a coil to continuously prepare the rare earth catalyst. It not only ensures that the components are fully mixed and reacted in the mixing unit to obtain a homogeneous system, but also because the disk The tube is a push-over flow reactor. In this coil, the mixture obtained after full contact in the mixing unit flows into the coil at a stable flow rate and moves forward in parallel. There is almost no backmixing along the direction of material movement, so that It can ensure that the time from the reaction material particles entering the coil to leaving the coil (that is, the residence time of the particles in the coil) is equal. Therefore, each component of the rare earth catalyst can be fully aged and reacted to obtain a catalyst with stable properties. Then the catalyst with stable properties obtained through continuous preparation is fed into the polymerization reaction system, and the performance of the obtained polymer will fluctuate less. According to a preferred embodiment of the present invention, when the linear velocity passing through the first coiled tube is 0.25-0.4cm/min, the linear velocity passing through the second coiled tube is 0.7-0.95cm/min, and the linear velocity passing through the second coiled tube is 0.7-0.95cm/min, When the linear speed of the third coiled tube is 0.9-1.25cm/min and the linear speed passing through the fourth coiled tube is 0.9-1.25cm/min, the properties of the polymer obtained are more stable. In addition, the continuous polymerization method of the present invention has continuously integrated the catalyst preparation process and the polymerization process, thereby not only improving production efficiency, reducing labor intensity, and reducing operating costs, but also easily realizing automated production and obtaining polymer products with stable performance. , which has great industrial application prospects.

Description of drawings

Figure 1 is a schematic diagram of the continuous polymerization method of conjugated dienes of the present invention.

Explanation of reference signs

1 First static mixer 2 First coil

3 First buffer tank 4 Second static mixer

5 Second coil 6 Second buffer tank

7 The third static mixer 8 The third coil

9 The third buffer tank 10 The fourth coil

11 aggregation unit

Detailed ways

The endpoints of ranges and any values disclosed herein are not limited to the precise range or value, but these ranges or values are to be understood to include values approaching such ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges. These values The scope shall be deemed to be specifically disclosed herein.

The invention provides a method for continuous polymerization of conjugated dienes, wherein the method includes the following steps:

1) In the presence of the first organic solvent, component A and component E are respectively sent to the first mixing unit for the first mixing, then enter the first coil for the first aging, and then enter the first In the buffer unit, the first mixture is obtained; the first mixture, component D and component B are sent to the second mixing unit respectively for the second mixing, and then enter the second coil for the second aging, Then it enters the second buffer unit to obtain the second mixture; the second mixture and component C are sent to the third mixing unit respectively for the third mixing, and then enter the third coil for the third aging. , and then enters the third buffer unit to obtain the third mixture; the third mixture is sent to the fourth coil for the fourth aging to obtain the rare earth catalyst;

2) Under polymerization reaction conditions, continuously feed the conjugated diene, the rare earth catalyst obtained in step 1) and the second organic solvent into the polymerization unit for contact,

Among them, component A is a neodymium phosphonate compound represented by formula (1); component B is an alkyl aluminum compound; component C is a halogenated compound; component D is a conjugated diene; component E is Compounds represented by formula (2),

In formula (1), R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are each independently a hydroxyl group, a C1-C20 alkyl group or a C1-C20 alkoxy group;

In formula (2), R ^d1 , R ^d2 and R ^d3 are each independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group.

According to the present invention, from the perspective of convenience of description, the mixing unit in which component A and component E are continuously contacted is called a "first mixing unit", and the continuous contact between the first mixture and component B and component D is called a "first mixing unit". The mixing unit in contact is called the "second mixing unit", and the mixing unit that continuously contacts the second mixture with component C is called the "third mixing unit". The type of the mixing unit is well known to those skilled in the art, as long as continuous and sufficient mixing can be achieved, and will not be described again here.

In the present invention, if necessary, the mixing unit can adopt an external jacket for temperature control operation. For example, the temperature in the mixing unit can be controlled within the required range through the circulating medium in the jacket. The circulating medium includes a heating medium and a cooling medium. The types of the heating medium and cooling medium are well known to those skilled in the art. For example, specific examples of the heating medium include but are not limited to hot water; specific examples of the cooling medium Including but not limited to ice-water mixture and frozen brine, preferably frozen brine.

As the mixing unit, one or more of a static mixer, a dynamic mixer and a stirring tank can be used. Since a static mixer has the advantage of saving energy, it is particularly preferred in the present invention that the mixing unit uses a static mixer.

The type of static mixer is well known to those skilled in the art and can be any of the existing static mixers with turbulence. For example, the sx model static mixer of Qidong Great Petrochemical Equipment Company, Nantong Fangsheng Petrochemical Company can be used. Equipment Co., Ltd.'s SH model static mixer and Hera (Shanghai) Industrial Technology Co., Ltd.'s K model static mixer, etc.

According to the present invention, the types of the coils (the first to fourth coils, hereinafter also referred to as coils) are well known to those skilled in the art. After in-depth research, the inventor of the present invention found that when the third coil is used, The linear speed of one coil is 0.25-0.4cm/min, the linear speed of the second coil is 0.7-0.95cm/min, the linear speed of the third coil is 0.9-1.25cm/min and When the linear velocity passing through the fourth coil is 0.9-1.25 cm/min, the flow pattern of the material in the reactor is closer to plug flow, and the activity of the obtained rare earth catalyst is higher. Further preferably, the coil is an adiabatic reactor, which is not only more conducive to sufficient aging and reaction among the above five components to form a catalyst with more stable properties, but also saves energy.

In the present invention, the diameter of the coiled pipe can be selected according to the scale of polymerization, for example, it can be 3-300 mm, preferably 5-100 mm.

In the present invention, the method of sending component A and component E respectively into the first mixing unit is not particularly limited. For example, a metering pump can be used to send component A solution and component E solution into the first mixing unit respectively. in the mixed unit.

In addition, the speed at which the component A solution and the component E solution are respectively fed into the first mixing unit can be selected according to the scale of the polymerization. For example, the feeding speed of the component A solution can be, for example, 100-2000 mL/ h, preferably 500-1000mL/h. The feeding speed of the component E solution can be, for example, 10-200 mL/h, preferably 50-100 mL/h.

In the present invention, the method of sending the first mixture, component D and component B into the second mixing unit respectively is not particularly limited. For example, a metering pump can be used to pump the first mixture, component D The solution and the component B solution are fed separately into the second mixing unit.

The speed of feeding the first mixture, component D solution and component B solution into the second mixing unit respectively can be selected according to the scale of polymerization. For example, the feeding speed of the first mixture can be Component A. The total speed of the solution and the component E solution, the feeding speed of the component D solution can be 50-2000mL/h, preferably 500-1000mL/h. The feeding speed of the component B solution can be 100-2000mL/h, preferably 300-1000mL/h.

In the present invention, the method of sending the second mixture and the component C solution into the third mixing unit respectively is not particularly limited. For example, a metering pump can be used to send the second mixture and the component C solution into the third mixing unit respectively. to the first mixing unit.

In addition, the speed at which the second mixture and the component C solution are respectively fed into the third mixing unit can be selected according to the scale of the polymerization. For example, the feeding speed of the second mixture can be the component A solution, The total speed of the component E solution, the component D solution and the component B solution, the feeding speed of the component C solution can be 100-1000mL/h, preferably 200-500mL/h.

According to the present invention, the type of the buffer unit (the first buffer unit to the fourth buffer unit, hereinafter also referred to as the buffer unit) is various containers for storing liquids known to those skilled in the art, and may be a buffer tank, for example.

According to the present invention, in step 1), although the rare earth catalyst of the present invention can be obtained as long as the five components of the catalyst are continuously contacted in the mixing unit according to the above method, and the mixture obtained by contact is continuously aged in the coil, There are no special restrictions on the contact and aging conditions. However, in order to eliminate or reduce the influence of various components in the air on catalyst preparation, preferably, the contact and aging are performed in an inert atmosphere. The inert atmosphere refers to any gas or gas mixture that does not chemically interact with the reactants and products, such as nitrogen and one or more gases from group zero of the periodic table of elements. In addition, the conditions for continuously contacting component A and component E in the first mixing unit usually also include temperature, and the temperature can be selected within a wide range, usually in order to further facilitate the interaction between the components. For uniform mixing and reaction, the temperature can be 10-60°C, preferably 30-50°C. In addition, the mixing time only needs to ensure that the components are fully mixed, for example, it can be 2-60 hours. The extension of the contact time is conducive to achieving molecular-level dispersion of each component, but taking into account the effect and efficiency, the conditions for the first aging include: the temperature can be 10-60°C, preferably 30-50°C. The residence time in the coil can be 2-60h, preferably 5-10h, and the linear speed in the first coil can be 0.1-50cm/min, preferably 0.1-25cm/min, and more preferably 0.2-10cm/ min, more preferably 0.2-5cm/min, more preferably 0.2-1cm/min, more preferably 0.3-0.8cm/min, more preferably 0.3-0.5cm/min, more preferably 0.3-0.4cm/min.

Similarly, the conditions for continuously contacting the first mixture with component B and component D in the second mixing unit also include: the temperature may be 0-50°C, preferably 20-40°C. The conditions for continuous aging of the mixture in the second coil also include: the temperature may be 0-50°C, preferably 20-40°C, and the residence time in the second coil may be 5-120 min, preferably 20-45min, the linear speed in the second coil can be 0.1-50cm/min, more preferably 0.1-25cm/min, more preferably 0.2-10cm/min, more preferably 0.3-8cm/min, more preferably It is 0.5-1cm/min, more preferably 0.6-1cm/min, more preferably 0.7-0.95cm/min.

The conditions for continuously contacting the second mixture and component C in the third mixing unit also include: the temperature may be 10-80°C, preferably 50-70°C. The conditions for continuous aging of the mixture in the coil also include that the temperature can be 10-80°C, preferably 50-70°C, and the residence time in the third coil can be 30-180min, preferably 90-150min , the linear speed in the third coil can be 0.1-50cm/min, more preferably 0.1-25cm/min, more preferably 0.2-10cm/min, more preferably 0.3-8cm/min, more preferably 0.5- 5cm/min, more preferably 0.6-2cm/min, more preferably 0.7-1.5cm/min, more preferably 0.8-1.3cm/min, further preferably 0.9-1.25.

The conditions for continuous aging of the third mixture in the fourth coil include: the temperature is 0-40°C, preferably 10-30°C, and the residence time in the fourth coil can be 1-48 hours, preferably It is 12-24 hours, and the linear speed in the fourth coil can be 0.1-50cm/min, more preferably 0.1-25cm/min, more preferably 0.2-10cm/min, more preferably 0.3-8cm/min, It is more preferably 0.5-5cm/min, more preferably 0.6-2cm/min, more preferably 0.7-1.5cm/min, more preferably 0.8-1.3cm/min, still more preferably 0.9-1.25.

According to the present invention, in step (1), the optional range of the amount of each component is wide. In order to further optimize the continuous polymerization method of the present invention, for the present invention, the molar ratio of component A and component E can be 1:0.2-0.4, preferably 1:0.25-0.35; the molar ratio of component A and component B can be 1:12-30, preferably 1:15-20; the molar ratio of component A and component C It can be 1:2-5, preferably 1:2.5-4.5; the molar ratio of component A and component D can be 1:10-80, preferably 1:35-65.

According to the present invention, the component A is a neodymium phosphonate compound represented by the following formula (1).

Formula 1)

Among them, R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are each independently a hydroxyl group, a C1-C20 alkyl group or a C1-C20 alkoxy group, preferably a hydroxyl group or a C4-C12 alkyl group. Or C4-C12 alkoxy group, more preferably hydroxyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, 2-ethylpentyl, n-hexyl , 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-butoxy, isobutoxy , sec-butoxy, tert-butoxy, n-pentyloxy, 2-methylpentyloxy, 2-ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-ethylhexyloxy base, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy or n-dodecyloxy.

In a preferred embodiment of the present invention, the neodymium phosphonate compound represented by formula (1) is one or more of the following compounds,

R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are compounds of 2-ethylhexyloxy,

R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are compounds of 2-ethylhexyl,

A compound in which R ^a1 , R ^b1 and R ^c1 are 2-ethylhexyl and R ^a2 , R ^b2 and R ^c2 are 2-ethylhexyloxy.

According to the present invention, the optional range of the types of the alkyl aluminum compounds is relatively wide, and all alkyl aluminum compounds commonly used in the field can achieve the purpose of the present invention. For the present invention, in step 1), the alkyl aluminum compound is preferably selected from trialkylaluminum and/or dialkylaluminum hydride, more preferably trimethylaluminum, triethylaluminum, tripropylaluminum, One of tributyl aluminum, tripentyl aluminum, trihexyl aluminum, triisobutylaluminum, diethyl aluminum hydride, dipropylaluminum hydride, dibutyl aluminum hydride and diisobutylaluminum hydride or Various.

According to the present invention, the optional range of the types of halogenated compounds is relatively wide, and all halogenated compounds commonly used in the field can achieve the purpose of the present invention. For the present invention, in step 1), the halogenated compound is preferably diethyl aluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, or monochloride. One or more of silane, dichlorosilane, trichlorosilane and silicon tetrachloride.

According to the present invention, the optional range of the types of conjugated dienes is relatively wide, and all conjugated dienes commonly used in the field can achieve the purpose of the present invention. For the present invention, in step 1) and step 2), the conjugated diene is preferably each independently a C ₄ -C ₆ conjugated diene, and further preferably is butadiene, isoprene, piperylene One or more of 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene and 2,3-dimethylbutadiene, more preferably butadiene and /or isoprene, particularly preferably butadiene.

According to the present invention, component E is a compound represented by formula (2).

Formula (2)

In formula (2), R ^d1 , R ^d2 and R ^d3 are each independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group, preferably a hydroxyl group, n-butyl group, isobutyl group or sec-butyl group. , tert-butyl, n-pentyl, 2-methylpentyl, 2-ethylpentyl, n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-Decyl, n-Undecyl, n-dodecyl, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, 2-methylpentyloxy, 2 -Ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-ethylhexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-11 Alkoxy or n-dodecyloxy.

In a preferred embodiment of the present invention, the compound represented by formula (2) is di(2-ethylhexyl)phosphate (R ^d1 and R ^d2 are 2-ethylhexyloxy and R ^d3 is hydroxyl) compound), 2-ethylhexyl mono-2-ethylhexyl phosphate (a compound in which R ^d1 is 2-ethylhexyl, R ^d2 is 2-ethylhexyloxy and R ^d3 is hydroxyl) and di-(2- One or more of ethylhexyl)phosphonic acids (compounds in which R ^d1 and R ^d2 are 2-ethylhexyl and R ^d3 is hydroxyl).

According to the present invention, the purpose of the present invention can be achieved according to the foregoing technical solutions. Taking into account the conversion rate of the conjugated diene and the properties of the resulting polymer, for the present invention, preferably, in step 2), the polymerization unit includes At least 2 polymerization reaction kettles in series, further preferably including 3-10 polymerization reaction kettles in series, more preferably including 3-5 polymerization reaction kettles in series.

Among them, the polymerization reaction kettle can use an external jacket for temperature control operation. For example, the temperature in the polymerization reaction kettle can be controlled within the required range through a circulating medium (heating medium or cooling medium) in the jacket. The types of heating medium and cooling medium used are well known to those skilled in the art. For example, specific examples of the heating medium include but are not limited to hot water; specific examples of the cooling medium include but are not limited to ice-water mixture and frozen brine. , preferably frozen brine.

Those skilled in the art can easily understand that in order to continuously use the rare earth catalyst prepared in step 1) for the production of polymers in step 2), that is, to realize the continuous integration of the preparation of the catalyst and the polymerization of conjugated dienes, according to the materials In the flow direction, the fourth coil is connected in series with the first polymerization reactor, so that the rare earth catalyst obtained by contacting in step 1) is directly sent to the polymerization unit.

According to the present invention, preferably, the method of the present invention further includes: under polymerization reaction conditions, before continuously sending the conjugated diene, the rare earth catalyst and the inert organic solvent into the polymerization unit for contact, the conjugated diene is Olefins, rare earth catalysts and inert organic solvents are premixed. The optional range of the premixing conditions is wide. The temperature and time of the premixing can be reasonably selected according to the flow rate of the conjugated diene, rare earth catalyst and inert organic solvent. Generally, the premixing is performed at normal temperature (5-40°C). It takes 5-20 minutes to mix the above three components evenly. The premixing can be carried out in a conventional kettle premixer. In this case, according to the flow direction of the material, the fourth coil is connected in series with the kettle-type premixer, and the kettle-type premixer is connected in series with the first polymerization reactor, thereby realizing the preparation and conjugation of the catalyst. Continuous integration of diene polymerization. The specific implementation process is well known to those skilled in the art and will not be described in detail here.

According to the present invention, the object of the present invention can be achieved according to the foregoing technical solutions. In order to further optimize the continuous polymerization method of the present invention, for the present invention, it is preferred that in step 2), the polymerization reaction conditions include: The temperature is independently -30°C to 80°C, preferably 0-70°C, and more preferably 10-60°C; the contact time in each polymerization reactor is independently 10-90min, preferably 20-80min, More preferably, it is 30-60 min; the total contact time in each polymerization reactor does not exceed 300 min, preferably 90-180 min, and more preferably 110-150 min.

According to the present invention, the amount of the rare earth catalyst can be appropriately selected based on the principles of industrial economy. Generally speaking, the smaller the amount of catalyst, the greater the molecular weight of the polymerized product obtained, but the slower the polymerization rate; the greater the amount of catalyst, the A faster polymerization rate will increase the cost, and may also increase the ash content in the polymerized product, which is not conducive to subsequent processing or application of the product. Therefore, considering all factors, the amount of the homogeneous rare earth catalyst is such that the amount of component A is 20-200 μmol relative to 1 mol of the component D;

According to the present invention, the second organic solvent may be any existing organic solvent that does not chemically interact with the reactants and reaction products. Generally, the organic solvents in step 1) and step 2) can be the same or different, and are each independently selected from one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes; specifically, they can be each independently selected from benzene. , toluene, ethylbenzene, xylene (including o-xylene, m-xylene and p-xylene), pentane and its isomers (for example: n-pentane, isopentane, methylcyclopentane, 2-methylcyclopentane pentane and 3-methylpentane), hexane and its isomers (for example: n-hexane, cyclohexane), heptane and its isomers (for example: n-heptane), octane and its isomers One or more of the following structures (for example: n-octane), cyclohexane and raffinate. The amount of the organic solvent used can be conventionally selected in the art and is not particularly limited. Generally speaking, in step 1), the amount of the first organic solvent can be such that the concentration of the rare earth catalyst is 1×10 ^-4 -1 mol/L based on the neodymium phosphonate compound represented by formula (1) , to ensure the smooth progress of the mixing and aging process and to obtain a highly active rare earth catalyst. In step 2), based on 100 parts by weight of conjugated diene, the amount of the second organic solvent can be 400-900 parts by weight, which not only enables the polymerization reaction to proceed smoothly, but also can obtain higher yields. Rate.

According to the present invention, after the polymerization reaction is completed, various methods commonly used in the art can be used to deactivate the active polymer. For example, active polymer chains can be deactivated by adding terminators to the polymerization reaction system. The type and amount of the terminator can be conventionally selected in the art and is not particularly limited, as long as the terminator can deactivate the polymer chain with active end groups. Generally, the terminator may be one or more selected from the group consisting of water, C ₁ -C ₆ aliphatic alcohols, C ₄ -C ₁₂ aliphatic carboxylic acids, and aryl polyhydroxy compounds. The aryl polyhydroxy compound refers to a compound in which at least two hydrogen atoms on the benzene ring are substituted by hydroxyl groups. Preferably, the terminator is one or more of water, methanol, ethanol, isopropyl alcohol and 2,6-di-tert-butylhydroquinone. The present invention has no particular limitation on the amount of the terminator, as long as the amount of the terminator can deactivate the active species in the polymer product, which will not be described again here.

The continuous polymerization method of the present invention will be briefly described below with reference to the accompanying drawings. Figure 1 is a schematic diagram of the method for continuous polymerization of conjugated dienes of the present invention. As shown in Figure 1, first, in the presence of the first organic solvent, component A and component E are pumped into the first static state by a metering pump respectively. In the mixer 1, it enters the first coil 2, and then enters the first buffer tank 3 to obtain the first mixture, and then the first mixture, component D and component B are pumped into the second static mixer 4 by a metering pump. , enters the second coil 5, and then enters the second buffer tank 6 to obtain the second mixture, and then the second mixture and component C are pumped into the third static mixer 7 by a metering pump, and then enter the third coil 8, Then it enters the third buffer tank 9 to obtain a third mixture, and then the third mixture is continuously aged in the fourth coil 10 to obtain a rare earth catalyst; the obtained rare earth catalyst is continuously sent to the polymerization unit 11 . Among them, the static mixer and the polymerization reaction kettle used in the polymerization unit adopt a circulating medium introduced into the external jacket for temperature control, thereby realizing the preparation of the catalyst and the continuous production of conjugated diene polymerization.

The present invention will be described in detail through examples below, but the present invention is not limited to the following examples.

In the following examples and comparative examples, the microstructure of the synthesized polymer product was measured using a German Bruker Tensor27 mid-infrared spectrometer and a German Bruker 400MHz nuclear magnetic resonance instrument. The solvent was deuterated chloroform; the Mooney viscosity was measured by an automatic Mooney viscometer ( SMV-300 type, purchased from Shimadzu Corporation) was measured, and the test temperature was 100°C.

In the following examples and comparative examples, the monomer conversion rate refers to the percentage of monomer converted into polymer, which is calculated by the ratio of the weight of the polymer to the weight of the monomer entering the polymerization section, that is,

In the following examples and comparative examples, neodymium phosphonate is a compound in formula (1) in which R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are 2-ethylhexyloxy groups (purchased from Inno Kai Company); the phosphonic acid is bis(2-ethylhexyl)phosphate (purchased from Bailingwei).

Example 1

This example is used to illustrate the continuous polymerization method provided by the present invention.

Aggregation according to the flow chart shown in Figure 1

(1) Preparation of rare earth catalysts

Under nitrogen protection, use a metering pump to continuously add a neodymium phosphonate/hexane solution with a concentration of 0.03 mol/L into the first static mixer (sx model purchased from Qidong Great Petrochemical Equipment Company, the same below). 0.1mol/L phosphonic acid/hexane solution, the control flow rate is 600mL/h and 40mL/h respectively, the operating temperature is 30°C, the residence time after entering the first coil (pipe diameter is 6mm) is 8h, and the linear speed is 0.38 cm/min. After the first buffer tank is filled with material, a metering pump is used to continuously add diisobutyl hydrogenation with a concentration of 0.55mol/L into the second static mixer (sx model purchased from Qidong Great Petrochemical Equipment Company, the same below) Aluminum/hexane solution and butadiene-hexane solution with a concentration of 1.2mol/L, flow rates are 523mL/h and 680mL/h respectively, operating temperature is 40°C, and residence time enters the second coil (pipe diameter is 6mm) is 20min, and the linear speed is 0.78cm/min. After the second buffer tank is filled with material, a metering pump is used to continuously add diethyl monochloride with a concentration of 0.17mol/L into the third static mixer (sx model purchased from Qidong Great Petrochemical Equipment Company, the same below) The aluminum/hexane solution has a flow rate of 280mL/h, an operating temperature of 60°C, a residence time of 120min when entering the third coil (pipe diameter: 6mm), and a linear speed of 0.94cm/min. After the material is filled into the third buffer tank, it is placed in the fourth coil (pipe diameter is 6mm), the residence time is 12 hours, the linear speed is 0.94cm/min, and a light yellow-green rare earth catalyst is obtained;

(2) Preparation of butadiene rubber

The rare earth catalyst obtained from the fourth coil outlet, butadiene (the molar ratio of Nd and Bd is 6×10 ^-5 ) and hexane (wherein, the flow rates of butadiene and hexane are 16.2kg/h respectively) , 120kg/h) are continuously fed into the kettle-type premixer and premixed at normal temperature to obtain mixed reaction raw materials. The mixed reaction raw materials are continuously fed into four polymerization reactors in series. The residence time of the materials in the four polymerization reactors is are all 40 minutes, and the circulating medium is passed through the jacket of each reactor. The temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 30°C, 40°C, and 50℃, 55℃. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 89-92%, the cis 1,4-structure content of the product is 98.3-98.5%, the weight average molecular weight is 2.91×10 ⁵ -3.08×10 ⁵ , and the molecular weight distribution index is 1.99-2.24. In the final mixed product, the content of cis 1,4-structure is 98.7%, the weight average molecular weight is 3.04×10 ⁵ , and the molecular weight distribution index is 2.13.

Example 2

This example is used to illustrate the continuous polymerization method provided by the present invention.

Aggregation according to the flow chart shown in Figure 1

(1) Preparation of rare earth catalysts

Under nitrogen protection, use a metering pump to continuously add a neodymium phosphonate/hexane solution with a concentration of 0.03 mol/L and a phosphonic acid/hexane solution with a concentration of 0.1 mol/L into the first static mixer. The control flow rates are respectively 560mL/h and 60mL/h, the operating temperature is 35°C, the residence time into the first coil (pipe diameter is 6mm) is 6h, and the linear speed is 0.37cm/min. After the first buffer tank is filled with material, use a metering pump to continuously add diisobutylaluminum hydride/hexane solution with a concentration of 0.55mol/L and butadiene with a concentration of 1.2mol/L into the second static mixer. Hexane solution, the flow rate is 413mL/h and 950mL/h respectively, the operating temperature is 20°C, the residence time entering the second coil (pipe diameter is 6mm) is 45min, and the linear speed is 0.93cm/min. After the second buffer tank is filled with material, use a metering pump to continuously add diethyl aluminum monochloride/hexane solution with a concentration of 0.17mol/L into the third static mixer, with a flow rate of 480mL/h and an operating temperature of 50 ℃, entering the third coil (pipe diameter is 6mm), the residence time is 150min, and the linear speed is 1.21cm/min. After the material is filled into the third buffer tank, it is placed in the fourth coil (pipe diameter is 6mm), the residence time is 15 hours, the linear speed is 1.21cm/min, and a light yellow-green rare earth catalyst is obtained;

(2) Preparation of butadiene rubber

The rare earth catalyst obtained from the fourth coil outlet, butadiene (the molar ratio of Nd to Bd is 5.6×10 ^-5 ) and hexane (the flow rates of butadiene and hexane are 16.2kg/h respectively) , 120kg/h) are continuously fed into the kettle-type premixer and premixed at normal temperature to obtain mixed reaction raw materials. The mixed reaction raw materials are continuously fed into four polymerization reactors in series. The residence time of the materials in the four polymerization reactors is are all 40 minutes, and the circulating medium is passed through the jacket of each reactor. The temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 30°C, 40°C, and 50℃, 55℃. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 88-93%, the cis 1,4-structure content of the product is 98.1-98.3%, the weight average molecular weight is 2.41×10 ⁵ -2.65×10 ⁵ , and the molecular weight distribution index is 2.25-2.48. In the final mixed product, the content of cis 1,4-structure is 98.2%, the weight average molecular weight is 2.54×10 ⁵ , and the molecular weight distribution index is 2.32.

Example 3

This example is used to illustrate the continuous polymerization method provided by the present invention.

Aggregation according to the flow chart shown in Figure 1

(1) Preparation of rare earth catalysts

Under nitrogen protection, use a metering pump to continuously add a neodymium phosphonate/hexane solution with a concentration of 0.03 mol/L and a phosphonic acid/hexane solution with a concentration of 0.1 mol/L into the first static mixer. The control flow rates are respectively 350mL/h and 70mL/h, the operating temperature is 50°C, the residence time into the first coil (pipe diameter is 6mm) is 5h, and the linear speed is 0.25cm/min. After the first buffer tank is filled with material, use a metering pump to continuously add diisobutylaluminum hydride/hexane solution with a concentration of 0.55mol/L and butadiene with a concentration of 1.2mol/L into the second static mixer. Hexane solution, the flow rate is 541mL/h and 850mL/h respectively, the operating temperature is 30°C, the residence time entering the second coil (pipe diameter is 6mm) is 25min, and the linear speed is 0.75cm/min. After the second buffer tank is filled with material, use a metering pump to continuously add diethyl aluminum monochloride/hexane solution with a concentration of 0.17mol/L into the third static mixer, with a flow rate of 400mL/h and an operating temperature of 45 ℃, entering the third coil (pipe diameter is 6mm), the residence time is 180min, and the linear speed is 0.98cm/min. After the material is filled with the third buffer tank, it enters the fourth coil (pipe diameter is 6mm), the residence time is 24 hours, the linear speed is 0.98cm/min, and a light yellow-green rare earth catalyst is obtained;

(2) Preparation of butadiene rubber

The rare earth catalyst obtained from the fourth coil outlet, butadiene (the molar ratio of Nd to Bd is 3.91×10 ^-5 ) and hexane (the flow rates of butadiene and hexane are 14.5kg/h respectively) , 120kg/h) are continuously fed into the kettle-type premixer and premixed at normal temperature to obtain mixed reaction raw materials. The mixed reaction raw materials are continuously fed into four polymerization reactors in series. The residence time of the materials in the four polymerization reactors is are all 40 minutes, and the circulating medium is passed through the jacket of each reactor. The temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 30°C, 40°C, and 50℃, 55℃. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 89-92%, the cis 1,4-structure content of the product is 98.0-98.5%, the weight average molecular weight is 2.51×10 ⁵ -2.78×10 ⁵ , and the molecular weight distribution index is 2.33-2.52. In the final mixed product, the content of cis 1,4-structure is 98.2%, the weight average molecular weight is 2.63×10 ⁵ , and the molecular weight distribution index is 2.45.

Example 4

This example is used to illustrate the continuous polymerization method provided by the present invention.

Aggregation according to the flow chart shown in Figure 1

(1) Preparation of rare earth catalysts

Under nitrogen protection, use a metering pump to continuously add a neodymium phosphonate/hexane solution with a concentration of 0.03 mol/L and a phosphonic acid/hexane solution with a concentration of 0.1 mol/L into the first static mixer. The control flow rates are respectively 500mL/h and 40mL/h, the operating temperature is 35°C, the residence time into the first coil (pipe diameter is 6mm) is 6h, and the linear speed is 0.32cm/min. After the first buffer tank is filled with material, use a metering pump to continuously add diisobutylaluminum hydride/hexane solution with a concentration of 0.55mol/L and butadiene with a concentration of 1.2mol/L into the second static mixer. Hexane solution, the flow rate is 620mL/h and 850mL/h respectively, the operating temperature is 50℃, the residence time entering the second coil (pipe diameter is 6mm) is 7min, and the linear speed is 0.82cm/min. After the second buffer tank is filled with material, use a metering pump to continuously add diethyl aluminum monochloride/hexane solution with a concentration of 0.17mol/L into the third static mixer, with a flow rate of 350mL/h and an operating temperature of 55 ℃, entering the third coil (pipe diameter is 6mm), the residence time is 120min, and the linear speed is 1.02cm/min. After the material is filled into the third buffer tank, it is placed in the fourth coil (pipe diameter is 6mm), the residence time is 18 hours, the linear speed is 1.02cm/min, and a light yellow-green rare earth catalyst is obtained;

(2) Preparation of butadiene rubber

The rare earth catalyst obtained from the fourth coil outlet, butadiene (the molar ratio of Nd to Bd is 5×10 ^-5 ) and hexane (wherein, the flow rates of butadiene and hexane are 16.2kg/h respectively) , 120kg/h) are continuously fed into the kettle-type premixer and premixed at normal temperature to obtain mixed reaction raw materials. The mixed reaction raw materials are continuously fed into four polymerization reactors in series. The residence time of the materials in the four polymerization reactors is are all 40 minutes, and the circulating medium is passed through the jacket of each reactor. The temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 30°C, 40°C, and 50℃, 55℃. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 89-92%, the cis 1,4-structure content of the product is 98.2-98.5%, the weight average molecular weight is 2.93×10 ⁵ -3.12×10 ⁵ , and the molecular weight distribution index is 2.48-2.79. In the final mixed product, the content of cis 1,4-structure is 98.3%, the weight average molecular weight is 3.02×10 ⁵ , and the molecular weight distribution index is 2.66.

Example 5

This example is used to illustrate the continuous polymerization method provided by the present invention.

Aggregation according to the flow chart shown in Figure 1

(1) Preparation of rare earth catalysts

Under nitrogen protection, use a metering pump to continuously add a neodymium phosphonate/hexane solution with a concentration of 0.04mol/L and a phosphonic acid/hexane solution with a concentration of 0.15mol/L into the first static mixer. The control flow rates are respectively 450mL/h and 28mL/h, the operating temperature is 35°C, the residence time into the first coil (pipe diameter is 6mm) is 6h, and the linear speed is 0.28cm/min. After the first buffer tank is filled with material, use a metering pump to continuously add diisobutylaluminum hydride/hexane solution with a concentration of 0.55mol/L and butadiene with a concentration of 1.5mol/L into the second static mixer. Hexane solution, the flow rate is 524mL/h and 450mL/h respectively, the operating temperature is 50℃, the residence time entering the second coil (pipe diameter is 6mm) is 20min, and the linear speed is 0.55cm/min. After the second buffer tank is filled with material, use a metering pump to continuously add diethyl aluminum monochloride/hexane solution with a concentration of 0.25 mol/L into the third static mixer, with a flow rate of 200 mL/h and an operating temperature of 55 ℃, entering the third coil (pipe diameter is 6mm), the residence time is 120min, and the linear speed is 0.67cm/min. After the material is filled into the third buffer tank, it is placed in the fourth coil (pipe diameter is 6mm), the residence time is 18 hours, the linear speed is 0.67m/min, and a light yellow-green rare earth catalyst is obtained;

(2) Preparation of butadiene rubber

The rare earth catalyst obtained from the fourth coil outlet, butadiene (the molar ratio of Nd to Bd is 5.65×10 ^-5 ) and hexane (where the flow rates of butadiene and hexane are 16.2kg/h respectively) , 120kg/h) are continuously fed into the kettle-type premixer and premixed at normal temperature to obtain mixed reaction raw materials. The mixed reaction raw materials are continuously fed into four polymerization reactors in series. The residence time of the materials in the four polymerization reactors is are all 40 minutes, and the circulating medium is passed through the jacket of each reactor. The temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 30°C, 40°C, and 50℃, 55℃. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 80-91%, the cis 1,4-structure content of the product is 98.3-98.7%, the weight average molecular weight is 2.75×10 ⁵ -3.01×10 ⁵ , and the molecular weight distribution index is 2.63-2.78. In the final mixed product, the content of cis 1,4-structure is 98.5%, the weight average molecular weight is 2.88×10 ⁵ , and the molecular weight distribution index is 2.71.

Comparative example 1

This example serves to illustrate a reference continuous polymerization process.

Butadiene rubber was prepared according to the method of Example 1, except that the coil was replaced by a reaction kettle. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 79-90%, the cis 1,4-structure content of the product is 98.2-98.7%, the weight average molecular weight is 2.43×10 ⁵ -3.36×10 ⁵ , and the molecular weight distribution index is 3.63-4.14. In the final mixed product, the content of cis 1,4-structure is 98.4%, the weight average molecular weight is 2.72×10 ⁵ , and the molecular weight distribution index is 3.87.

Comparative example 2

This example serves to illustrate the reference polymerization method.

(1) Preparation of rare earth catalysts

The rare earth catalyst was prepared according to the order of addition, molar ratio between components, reaction temperature and reaction time in Example 1, except that a batch preparation method was used. Specifically: under nitrogen protection, add 12.3L of neodymium phosphonate/hexane solution with a concentration of 0.03mol/L, 0.8L of phosphonic acid/hexane solution with a concentration of 0.1mol/L, and 10.7L of a concentration of 0.55mol/L. Diisobutylaluminum monohydride/hexane solution and 14L of butadiene/hexane solution with a concentration of 1.2mol/L were added to a reaction kettle with a volume of 100L, and the reaction was carried out at 40°C for 20 minutes. Then, after the temperature of the reaction kettle was raised to 60°C, 5.6L of diethylaluminum monochloride/hexane solution with a concentration of 0.17mol/L was added to the reaction kettle, and the reaction was carried out for 2 hours and 20 minutes to prepare a homogeneous rare earth catalyst. .

(2) Preparation of butadiene rubber

The rare earth catalyst (flow rate: 1.39L/h) and butadiene monomer (flow rate: 16.2kg/h) prepared by the batch method of step (1) (the molar ratio of Nd to Bd is 6×10 ^-5 ) and hexane (120kg/h) were sent to the polymerization section, and the continuous polymerization method was the same as in Example 1. After the continuous production runs smoothly, take a certain amount of glue from the outlet of the fourth reaction kettle every 4 hours, terminate it, remove the solvent, and dry it for analysis and testing. The results of 24 consecutive samplings are: the monomer conversion rate is 72-88%, the cis 1,4-structure content of the product is 98.0-98.7%, the weight average molecular weight is 2.13×10 ⁵ -3.68×10 ⁵ , and the molecular weight distribution index is 2.78-3.58. The final mixed product has a cis 1,4-structure content of 98.2%, a weight average molecular weight of 2.83×10 ⁵ , and a molecular weight distribution index of 4.36.

From the comparison between Examples 1-5 and Comparative Examples 1-2, it can be seen that using the continuous polymerization method provided by the present invention can make the molecular weight and distribution of the obtained polymer more stable, less volatile, and more stable in performance. From the comparison between Examples 1-4 and 5, it can be seen that when the linear speed passing through the first coil is 0.25-0.4cm/min, and the linear speed passing through the second coil is 0.7-0.95cm /min, the linear velocity passing through the third coil is 0.9-1.25cm/min, and the linear velocity passing through the fourth coil is 0.9-1.25cm/min, the properties of the polymer obtained are more stable. In addition, the continuous polymerization method of the present invention not only improves production efficiency, reduces labor intensity, and reduces operating costs by continuously integrating the catalyst preparation process and the polymerization process, but also easily realizes automated production, and has great industrial application prospects.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, many simple modifications can be made to the technical solution of the present invention, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the disclosed content of the present invention. All belong to the protection scope of the present invention.

Claims (10)

1. A method for continuous polymerization of conjugated dienes, characterized in that the method includes the following steps: 1) In the presence of the first organic solvent, component A and component E are respectively sent to the first mixing unit for the first mixing, then enter the first coil for the first aging, and then enter the first In the buffer unit, the first mixture is obtained; the first mixture, component D and component B are sent to the second mixing unit respectively for the second mixing, and then enter the second coil for the second aging, Then it enters the second buffer unit to obtain the second mixture; the second mixture and component C are sent to the third mixing unit respectively for the third mixing, and then enter the third coil for the third aging. , and then enters the third buffer unit to obtain the third mixture; the third mixture is sent to the fourth coil for the fourth aging to obtain the rare earth catalyst; 2) Under polymerization reaction conditions, continuously feed the conjugated diene, the rare earth catalyst obtained in step 1) and the second organic solvent into the polymerization unit for contact, Among them, component A is a neodymium phosphonate compound represented by formula (1); component B is an alkyl aluminum compound; component C is a halogenated compound; component D is a conjugated diene; component E is Compounds represented by formula (2), Formula 1) Formula (2)/> In formula (1), R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are each independently a hydroxyl group, a C1-C20 alkyl group or a C1-C20 alkoxy group; In formula (2), R ^d1 , R ^d2 and R ^d3 are each independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group. 2. The method according to claim 1, wherein the first mixing conditions include: a temperature of 10-60°C, preferably 30-50°C; Preferably, the conditions for the first aging include: the temperature is 10-60°C, the residence time in the first coil is 2-60h, preferably 5-10h, and the linear speed in the first coil is 0.1-50cm/min, preferably 0.3-0.5cm/min; Preferably, the second mixing conditions include: temperature is 0-50°C, preferably 20-40°C; Preferably, the second aging conditions include: the temperature is 0-50°C, the residence time in the second coil is 5-120min, preferably 20-45min, and the linear speed in the second coil is 0.1-50cm/min, preferably 0.6-1cm/min; Preferably, the third mixing conditions include: temperature is 10-80°C, preferably 50-70°C; Preferably, the third aging conditions include: the temperature is 10-80°C, the residence time in the third coil is 30-180min, preferably 90-150min, and the linear speed in the third coil is 0.1-50cm/min, preferably 0.7-1.5cm/min; Preferably, the conditions for the fourth aging include: the temperature is 0-40°C, the residence time in the fourth coil is 1-48 hours, preferably 12-24 hours, and the line in the fourth coil is The speed is 0.1-50cm/min, preferably 0.7-1.5cm/min. Preferably, the first mixing unit, the second mixing unit and the third mixing unit are static mixers; Preferably, the first buffer unit, the second buffer unit and the third buffer unit are buffer tanks. 3. The method according to claim 1, wherein the molar ratio of component A and component E is 1:0.2-0.4; Preferably, the molar ratio of component A and component B is 1:12-30; Preferably, the molar ratio of component A and component C is 1:2-5; Preferably, the molar ratio of component A and component D is 1:10-80. 4. The method according to any one of claims 1 to 3, wherein in formula (1), R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are each independently a hydroxyl group, C4- C12 alkyl group or C4-C12 alkoxy group, preferably hydroxyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, 2-ethylpentyl , n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-butoxy, iso Butoxy, sec-butoxy, tert-butoxy, n-pentyloxy, 2-methylpentyloxy, 2-ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-ethyl Hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy or n-dodecyloxy; In formula (2), R ^d1 , R ^d2 and R ^d3 are each independently hydroxyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, 2-ethyl Pentyl, n-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-butoxy base, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, 2-methylpentyloxy, 2-ethylpentyloxy, n-hexyloxy, 2-methylhexyloxy, 2-ethylhexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy or n-dodecyloxy; Preferably, the neodymium phosphonate compound represented by formula (1) is one or more of the following compounds, R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are compounds of 2-ethylhexyloxy, R ^a1 , R ^a2 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are compounds of 2-ethylhexyl, A compound in which R ^a1 , R ^b1 and R ^c1 are 2-ethylhexyl and R ^a2 , R ^b2 and R ^c2 are 2-ethylhexyloxy; Preferably, the compound represented by formula (2) is di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester and di-(2-ethylhexyl)phosphonic acid. of one or more. 5. The method according to any one of claims 1-3, wherein the alkyl aluminum compound is selected from trialkyl aluminum and/or dialkyl aluminum hydride; Preferably, the alkyl aluminum compound is trimethylaluminum, triethylaluminum, tripropylaluminum, tributyl aluminum, tripentyl aluminum, trihexyl aluminum, triisobutylaluminum, diethyl aluminum One or more of aluminum hydride, dipropylaluminum hydride, dibutylaluminum hydride and diisobutylaluminum hydride; The halogenated compounds are diethyl aluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, monochlorosilane, dichlorosilane, trichlorosilane and One or more types of silicon tetrachloride. 6. The method according to any one of claims 1-3, wherein the conjugated diene is butadiene, isoprene, piperylene, 1,3-pentadiene, 1, One or more of 3-hexadiene, 2,4-hexadiene and 2,3-dimethylbutadiene; Preferably, the first organic solvent is one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes; Preferably, the amount of the first organic solvent is such that the concentration of the rare earth catalyst is 1×10 ^-4 -1 mol/L based on the neodymium phosphonate compound represented by formula (1). 7. The method according to any one of claims 1 to 3, wherein the rare earth catalyst is used in an amount such that the amount of component A is 20-200 μmol relative to 1 mol of component D; Preferably, the second organic solvent is one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes; Preferably, based on 100 parts by weight of conjugated diene, the amount of the second organic solvent is 400-900 parts by weight. 8. The method according to any one of claims 1-3, wherein in step 2), the polymerization unit includes at least 2 polymerization reactors in series, preferably 3-10 polymerization reactors in series, More preferably, it includes 3-5 polymerization reactors in series. 9. The method according to claim 8, wherein, according to the flow direction of the material, the fourth coil is connected in series with the first polymerization reactor, so that the rare earth catalyst obtained in step 1) is directly sent to the polymerization unit. 10. The method according to claim 8 or 9, wherein in step 2), the polymerization reaction conditions include: the temperature in each polymerization reactor is independently -30°C to 80°C, preferably 0- 70°C, more preferably 10-60°C; the contact time in each polymerization reactor is independently 10-90min, preferably 20-80min, more preferably 30-60min; the contact time in each polymerization reactor is The total time does not exceed 300min, preferably 90-180min, more preferably 110-150min.