Conjugated diene continuous polymerization method

Abstract

The invention relates to the field of rubber, and discloses a continuous polymerization method of conjugated diene. The method comprises the following steps: 1) mixing a component A and a component E, performing homogenization treatment and first aging, mixing a first mixture, a component D and a component B, performing second aging, mixing the mixture and a component C, performing third aging, and performing fourth aging on the mixture to obtain a rare earth catalyst; and 2) under a polymerization reaction condition, conjugated diene, the rare earth catalyst obtained in the step 1) and a second organic solvent are continuously fed into a polymerization unit for contact, and the homogenizing stirring linear speed of the homogenizing treatment is 8-20 m / s. According to the method, a catalyst preparation process and a polymerization process are continuously integrated, so that the production efficiency is improved, the labor intensity is reduced, the operation cost is reduced, automatic production is easily realized, a polymerization product with stable performance is obtained, and the method has a great industrial application prospect.

Description

Technical Field

[0001] The invention relates to the field of rubber, in particular to a method for continuous polymerization of conjugated dienes. Background Art

[0002] Compared with lithium, nickel, titanium and cobalt-based cis-butadiene rubber, cis-butadiene rubber prepared by rare earth catalysts has the highest cis structure and the lowest vinyl unit, and the branching degree is very small, which makes the macromolecular chain have high regularity and perfect linear structure, giving rare earth cis-butadiene rubber high strength, high wear resistance and good dynamic mechanical properties to ensure that the tires made of it meet the development needs in terms of high speed, energy saving, safety and environmental protection, and are particularly suitable for tread rubber and sidewall rubber. Therefore, rare earth cis-butadiene rubber is considered to be a cis-butadiene rubber with the best development prospects.

[0003] At present, the methods for preparing rare earth catalysts all adopt the intermittent aging method without exception. For example, CN101045768A discloses a rare earth catalyst and its preparation method, and specifically discloses that the preparation method of the catalyst includes adding rare earth organic compound, conjugated diene and alkyl aluminum in an aging container in sequence, reacting for 1-10 minutes, and then adding chloride to continue the reaction for 5 minutes to 24 hours. Michelin Company disclosed a synthetic polyisoprene and its preparation method in CN1479754A, wherein the rare earth catalyst used is composed of conjugated diene / rare earth phosphate / alkyl aluminum / halide, and its preparation method is relatively complicated and 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 preparation of the catalyst by intermittent aging will cause fluctuations in the performance of the polymer product, because: although each batch of catalysts is prepared according to certain conditions, it is difficult to control them to be exactly the same, so that the performance of the obtained catalyst is still different, and the performance of the polymer finally obtained is greatly fluctuated. Summary of the invention

[0004] The object of the present invention is to provide a novel method for continuous polymerization of conjugated dienes, which continuously integrates a catalyst preparation process and a polymerization process, thereby not only improving production efficiency, reducing labor intensity, and reducing operating costs, but also easily realizing automated production to obtain a polymer product with stable performance, and having great industrial application prospects.

[0005] The applicant of the present application has found through in-depth research that the neodymium carboxylate used in rare earth polymerization is usually in an associated state. If it is not treated, it is easy to form multiple active centers, which will lead to reduced efficiency of neodymium use and poor polymer uniformity. By adding a homogenizer to disassociate before aging the catalyst, the use of the catalyst can be reduced and the stability of the catalyst can be further improved.

[0006] In order to achieve the above object, the present invention provides a method for continuous polymerization of conjugated dienes, characterized in that the method comprises the following steps:

[0007] 1) In the presence of a first organic solvent, component A and component E are respectively sent to a first mixing unit for first mixing, then enter a homogenizer for homogenization, enter a first coil for first aging, and then enter a first buffer unit to obtain a first mixture; the first mixture, component D and component B are respectively sent to a second mixing unit for second mixing, then enter a second coil for second aging, and then enter a second buffer unit to obtain a second mixture; the second mixture and component C are respectively sent to a third mixing unit for third mixing, then enter a third coil for third aging, and then enter a third buffer unit to obtain a third mixture; the third mixture is sent to a fourth coil for fourth aging to obtain a rare earth catalyst;

[0008] 2) under polymerization reaction conditions, the conjugated diene, the rare earth catalyst obtained in step 1) and the second organic solvent are continuously fed into the polymerization unit for contact,

[0009] Wherein, the homogenizing stirring linear speed of the homogenizing treatment is 8-20m / s,

[0010] 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 a compound represented by formula (2),

[0011] Formula (1) Formula (2)

[0012] In formula (1), R a1 , R a2 , R b1 , R b2 , R c1 and R c2 Each is independently a hydroxyl group, a C1-C20 alkyl group or a C1-C20 alkoxy group;

[0013] In formula (2), R d1 , R d2 and R d3 Each is independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group.

[0014] Preferably, the homogenization treatment conditions include: homogenization stirring linear speed of 10-20 m / s, and residence time of 3-6 min.

[0015] Preferably, the conditions for the first mixing include: a temperature of 10-60°C, preferably 30-50°C.

[0016] Preferably, the first aging conditions include: temperature of 10-60°C, residence time in the first coil of 2-60h, preferably 5-10h, and linear speed in the first coil of 0.1-50cm / min, preferably 0.15-0.5cm / min.

[0017] Preferably, the second mixing conditions include: a temperature of 0-50°C, preferably 20-40°C.

[0018] Preferably, the second aging conditions include: temperature of 0-50°C, residence time in the second coil of 5-120 min, preferably 20-45 min, and linear speed in the second coil of 0.1-50 cm / min, preferably 0.5-1 cm / min.

[0019] Preferably, the conditions for the third mixing include: a temperature of 10-80°C, preferably 50-70°C.

[0020] Preferably, the conditions for the third aging include: a temperature of 10-80° C., a residence time in the third coil of 30-180 min, preferably 90-150 min, and a linear speed in the third coil of 0.1-50 cm / min, preferably 0.6-1.5 cm / min.

[0021] Preferably, the conditions for the fourth aging include: a temperature of 0-40° C., a residence time in the fourth coil of 1-48 hours, preferably 12-24 hours, and a linear speed in the fourth coil of 0.1-50 cm / min, preferably 0.6-1.5 cm / min.

[0022] Preferably, the first mixing unit, the second mixing unit and the third mixing unit are static mixers.

[0023] Preferably, the first buffer unit, the second buffer unit and the third buffer unit are buffer tanks.

[0024] Preferably, the molar ratio of the component A to the component E is 1:0.2-0.4.

[0025] Preferably, the molar ratio of the component A to the component B is 1:12-30.

[0026] Preferably, the molar ratio of the component A to the component C is 1:2-5.

[0027] Preferably, the molar ratio of the component A to the component D is 1:10-80.

[0028] Preferably, in formula (1), R a1 , R a2 , R b1 , R b2 , R c1 and R c2 Each is independently hydroxy, C4-C12 alkyl or C4-C12 alkoxy, preferably hydroxy, 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-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyloxy, n-octyl, n-nonyl, n-decyl, n-undecyloxy or n-dodecyloxy.

[0029] In formula (2), R d1 , R d2 and R d3 Each is independently hydroxy, 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-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyloxy, n-octyl, n-nonyl, n-decyl, n-undecyloxy or n-dodecyloxy.

[0030] Preferably, the neodymium phosphonate compound represented by formula (1) is one or more of the following compounds:

[0031] R a1 , R a2 , R b1 , R b2 , R c1 and R c2 A compound which is 2-ethylhexyloxy,

[0032] R a1 , R a2 , R b1 , R b2 , R c1 and R c2 A compound containing 2-ethylhexyl,

[0033] R a1 , R b1 and R c1 The compound is 2-ethylhexyl and R a2 , R b2 and Rc2 It is a 2-ethylhexyloxy compound.

[0034] Preferably, the compound represented by formula (2) is one or more of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester and di-(2-ethylhexyl)phosphonic acid.

[0035] Preferably, the alkyl aluminum compound is selected from trialkyl aluminum and / or dialkyl aluminum hydride.

[0036] Preferably, the alkyl aluminum compound is one or more of trimethyl aluminum, triethyl aluminum, tripropyl aluminum, tributyl aluminum, tripentylaluminum, trihexylaluminum, triisobutylaluminum, diethylaluminum hydride, dipropylaluminum hydride, dibutylaluminum hydride and diisobutylaluminum hydride.

[0037] The halogenated compound is one or more of diethylaluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, monochlorosilane, dichlorosilane, trichlorosilane and silicon tetrachloride.

[0038] Preferably, the conjugated diene is one or more of butadiene, isoprene, piperylene, 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene and 2,3-dimethylbutadiene.

[0039] Preferably, the first organic solvent is one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes;

[0040] Preferably, the amount of the first organic solvent used can be such that, based on the neodymium phosphonate compound represented by formula (1), the concentration of the rare earth catalyst is 1×10 -4 -1mol / L.

[0041] Preferably, the amount of the rare earth catalyst used is such that the amount of component A used is 20-200 μmol relative to 1 mol of component D.

[0042] Preferably, the second organic solvent is one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes.

[0043] Preferably, based on 100 parts by weight of the conjugated diene, the amount of the second organic solvent is 400-900 parts by weight.

[0044] Preferably, in step 2), the polymerization unit comprises at least 2 polymerization reactors connected in series, preferably 3-10 polymerization reactors connected in series, and more preferably 3-5 polymerization reactors connected in series.

[0045] 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 fed into the polymerization unit.

[0046] 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, and more preferably 10-60°C; the contact time in each polymerization reactor is independently 10-90min, preferably 20-80min, and more preferably 30-60min; the total contact time in each polymerization reactor does not exceed 300min, preferably 90-180min, and more preferably 110-150min.

[0047] The inventor of the present invention has found that in the industrial production of conjugated diene polymers, an intermittent process is used to prepare a catalyst, and the prepared catalyst needs to be stored in a catalyst storage tank and can be used up after a period of time. During this period of time, the catalyst components still react with each other, so that its properties change, thereby causing the molecular weight and distribution of the polymer products produced at different times to change in the process of continuous polymerization to produce conjugated diene polymers, and these different molecular weights and the polymers distributed therein are mixed in a glue tank or a coagulant, and the final product is actually a mixture, showing a wider molecular weight distribution. However, the wider molecular weight distribution of polymers can cause the vulcanization network of vulcanized rubber to be more sparse, and the density of the elastic effective part in the network decreases, thereby causing the reduction of the physical and mechanical properties of the vulcanized rubber, limiting its application. In addition, the use of intermittent aging to prepare catalysts has brought many inconveniences to production, such as the need to repeatedly carry out catalyst preparation work, labor intensity is large, control costs are high, non-productive operation time is very long, and the loss of materials is large.

[0048] The present invention skillfully combines a mixing unit (preferably a static mixer) and a coil to continuously prepare a rare earth catalyst, which can not only ensure that the components are fully mixed and reacted in the mixing unit to obtain a homogeneous system, but also because the coil is a push-flat flow reactor, in the coil, the mixture obtained after full contact in the mixing unit flows into the coil at a stable flow rate, moves forward in parallel, and there is almost no back mixing along the direction of material movement, thereby ensuring that the time from the reaction material particles entering the coil to leaving the coil (i.e., the residence time of the particles in the coil) is equal. Therefore, the components of the rare earth catalyst can be fully aged and reacted to obtain a catalyst with stable properties. The catalyst with stable properties obtained by continuous preparation is then sent to a polymerization reaction system, and the performance fluctuation of the obtained polymer is small. According to a preferred embodiment of the present invention, when the linear velocity through the first coil is 0.15-0.4 cm / min, the linear velocity through the second coil is 0.7-0.95 cm / min, the linear velocity through the third coil is 0.9-1.25 cm / min, and the linear velocity through the fourth coil is 0.9-1.25 cm / min, the performance of the obtained polymer is 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, obtaining a polymer product with stable performance, and having great industrial application prospects.

[0049] In addition, the inventors of the present invention have also found that the neodymium carboxylate used in rare earth polymerization is usually in an associated state. If it is not treated, it is easy to form multiple active centers, which will lead to reduced efficiency of neodymium use and poor polymer uniformity. By adding a homogenizer to disassociate before aging the catalyst, the use of the catalyst can be reduced and the stability of the catalyst can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of the method for continuous polymerization of conjugated dienes of the present invention.

[0051] Description of Reference Numerals

[0052] 1 First static mixer 2 Homogenizer

[0053] 3 First coil 4 First buffer tank

[0054] 5 Second static mixer 6 Second coil

[0055] 7 Second buffer tank 8 Third static mixer

[0056] 9 The third coil 10 The third buffer tank

[0057] 11 Fourth coil 12 Aggregation unit DETAILED DESCRIPTION

[0058] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0059] The present invention provides a method for continuous polymerization of conjugated dienes, wherein the method comprises the following steps:

[0060] 1) In the presence of a first organic solvent, component A and component E are respectively sent to a first mixing unit for first mixing, then enter a homogenizer for homogenization, enter a first coil for first aging, and then enter a first buffer unit to obtain a first mixture; the first mixture, component D and component B are respectively sent to a second mixing unit for second mixing, then enter a second coil for second aging, and then enter a second buffer unit to obtain a second mixture; the second mixture and component C are respectively sent to a third mixing unit for third mixing, then enter a third coil for third aging, and then enter a third buffer unit to obtain a third mixture; the third mixture is sent to a fourth coil for fourth aging to obtain a rare earth catalyst;

[0061] 2) under polymerization reaction conditions, the conjugated diene, the rare earth catalyst obtained in step 1) and the second organic solvent are continuously fed into the polymerization unit for contact,

[0062] Wherein, the homogenizing stirring linear speed of the homogenizing treatment is 8-20m / s,

[0063] 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 a compound represented by formula (2),

[0064] Formula (1) Formula (2)

[0065] In formula (1), R a1 , R a2 , R b1 , R b2 , R c1 and R c2 Each is independently a hydroxyl group, a C1-C20 alkyl group or a C1-C20 alkoxy group;

[0066] In formula (2), R d1, R d2 and R d3 Each is independently a hydroxyl group, a C4-C12 alkyl group or a C4-C12 alkoxy group.

[0067] In the present invention, "homogeneous stirring linear velocity" refers to the movement velocity of the outer apex of the homogenous stirring blade in the liquid.

[0068] According to the present invention, for the sake of convenience of description, the mixing unit in which component A and component E are continuously in contact is called the "first mixing unit", the mixing unit in which the first mixture is continuously in contact with components B and D is called the "second mixing unit", and the mixing unit in which the second mixture is continuously in contact with component C is called the "third mixing unit". The types of the mixing units are well known to those skilled in the art, and any type of mixing unit can be used as long as continuous and sufficient mixing can be achieved, and will not be described in detail herein.

[0069] In the present invention, the mixing unit may adopt an external jacket for temperature control operation as required, for example, the temperature in the static mixer may be controlled within a required range by a circulating medium in the jacket. The circulating medium includes a heating medium and a cooling medium, and the types of the heating medium and the 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 include but are not limited to ice-water mixtures and frozen brine, preferably frozen brine.

[0070] As the mixing unit, one or more of a static mixer, a dynamic mixer and a stirred tank can be used. Since a static mixer has the advantage of energy saving, it is particularly preferred in the present invention that the mixing unit uses a static mixer.

[0071] The types of the static mixer are well known to those skilled in the art, and may be various existing static mixers with turbulence, for example, the static mixer of model SX of Qidong Great Petrochemical Equipment Co., Ltd., the static mixer of model SH of Nantong Fangsheng Petrochemical Equipment Co., Ltd., and the static mixer of model K of Hera (Shanghai) Industrial Technology Co., Ltd., etc.

[0072] According to the present invention, the types of the coils (the first coil to the fourth coil, hereinafter referred to as coils) are well known to those skilled in the art. The inventors of the present invention have found through in-depth research that when the linear velocity through the first coil is 0.15-0.4 cm / min, the linear velocity through the second coil is 0.7-0.95 cm / min, the linear velocity through the third coil is 0.9-1.25 cm / min, and the linear velocity through the fourth coil is 0.9-1.25 cm / min, the flow pattern of the material in the reactor is closer to the piston 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 the full aging and reaction between the above five components, forming a catalyst with more stable properties, but also can save energy.

[0073] In the present invention, the diameter of the coil can be selected according to the scale of polymerization, for example, it can be 3-300 mm, preferably 5-100 mm.

[0074] In the present invention, the method of feeding component A and component E into the first mixing unit is not particularly limited. For example, a metering pump may be used to feed the component A solution and the component E solution into the first mixing unit.

[0075] In addition, the speeds of feeding the component A solution and the component E solution into the first mixing unit can be selected according to the scale of polymerization, for example, the feeding speed of the component A solution can be 100-2000 mL / h, preferably 500-1000 mL / h. The feeding speed of the component E solution can be 10-200 mL / h, preferably 50-100 mL / h.

[0076] In the present invention, after the first mixing, the mixture enters the homogenizer for homogenization, and the homogenization stirring line speed of the homogenization treatment is 5-30 m / s. Preferably, the conditions of the homogenization treatment include: the homogenization stirring line speed is 10-20 m / s, and the residence time is 3-6 min; more preferably, the conditions of the homogenization treatment include: the homogenization stirring line speed is 15-18 m / s, and the residence time is 3.5-4 min.

[0077] As the homogenizer, for example, an in-line homogenizer of model F22Z manufactured by Fluker Corporation can be used.

[0078] In the present invention, the method of feeding the first mixture, component D and component B into the second mixing unit is not particularly limited. For example, a metering pump can be used to feed the first mixture, component D solution and component B solution into the second mixing unit.

[0079] The speed of feeding the first mixture, component D solution and component B solution into the second mixing unit can be selected according to the scale of polymerization. For example, the feeding speed of the first mixture can be the total speed of component A solution and component E solution, the feeding speed of component D solution can be 50-2000mL / h, preferably 500-1000mL / h. The feeding speed of component B solution can be 100-2000mL / h, preferably 300-1000mL / h.

[0080] In the present invention, the method of feeding the second mixture and component C into the third mixing unit respectively is not particularly limited. For example, a metering pump may be used to feed the second mixture and component C solution into the first mixing unit respectively.

[0081] In addition, the speeds at which the second mixture and 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 total speed of component A solution, component E solution, component D solution and component B solution, and the feeding speed of component C solution can be 100-1000mL / h, preferably 200-500mL / h.

[0082] According to the present invention, the types of the buffer units (the first to fourth buffer units, hereinafter also referred to as buffer units) are various containers for storing liquids known to those skilled in the art, for example, buffer tanks.

[0083] According to the present invention, in step 1), although the rare earth catalyst of the present invention can be obtained by continuously contacting the five components of the catalyst in the mixing unit according to the above method, and continuously aging the contacted mixture in the coil, there is no particular restriction on the contact and aging conditions. However, in order to eliminate or reduce the influence of the components in the air on the catalyst preparation, preferably, the contact and aging are carried out in an inert atmosphere. The inert atmosphere refers to any gas or gas mixture that does not chemically react with the reactants and products, such as nitrogen and one or more of the zero group gases of the periodic table. In addition, the conditions for continuously contacting component A and component E in the first mixing unit generally also include temperature, and the temperature can be selected in a wide range. Usually, in order to further facilitate the uniform mixing and reaction between the components, 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 2-60h. The extension of contact time is beneficial to the molecular-level dispersion of each component, but considering the effect and efficiency comprehensively, the conditions of the first aging include: the temperature can be 10-60°C, preferably 30-50°C, the residence time in the first 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, more preferably 0.15-10cm / min, more preferably 0.15-5cm / min, more preferably 0.15-1cm / min, more preferably 0.16-0.8cm / min, more preferably 0.18-0.5cm / min, more preferably 0.18-0.4cm / min.

[0084] Similarly, the conditions for continuously contacting the first mixture with component B and component D in the second mixing unit also include: the temperature can be 0-50° C., preferably 20-40° C. The conditions for continuously aging the mixture in the second coil also include: the temperature can be 0-50° C., preferably 20-40° C., the residence time in the second coil can be 5-120 min, preferably 20-45 min, and the linear speed in the second coil can be 0.1-50 cm / min, more preferably 0.1-25 cm / min, more preferably 0.2-10 cm / min, more preferably 0.3-8 cm / min, more preferably 0.6-1 cm / min, more preferably 0.5-1 cm / min, more preferably 0.5-0.95 cm / min.

[0085] The conditions for continuously contacting the second mixture with component C in the third mixing unit also include: the temperature can be 10-80° C., preferably 50-70° C. The conditions for continuously aging the mixture in the coil also include: the temperature can be 10-80° C., preferably 50-70° C., the residence time in the third coil can be 30-180 min, preferably 90-150 min, and the linear speed in the third coil can be 0.1-50 cm / min, more preferably 0.1-25 cm / min, more preferably 0.2-10 cm / min, more preferably 0.3-8 cm / min, more preferably 0.5-5 cm / min, more preferably 0.6-2 cm / min, more preferably 0.7-1.5 cm / min, more preferably 0.7-1.3 cm / min, and further preferably 0.6-1.25.

[0086] The conditions for continuously aging the third mixture in the fourth coil include: a temperature of 0-40°C, preferably 10-30°C, a residence time in the fourth coil of 1-48 hours, preferably 12-24 hours, and a linear speed in the fourth coil of 0.1-50 cm / min, more preferably 0.1-25 cm / min, more preferably 0.2-10 cm / min, more preferably 0.3-8 cm / min, more preferably 0.5-5 cm / min, more preferably 0.6-2 cm / min, more preferably 0.7-1.5 cm / min, more preferably 0.7-1.3 cm / min, and further preferably 0.6-1.25.

[0087] According to the present invention, in step (1), the optional range of the amount of each component is relatively wide. In order to further optimize the continuous polymerization method of the present invention, according to the present invention, the molar ratio of component A to component E is 1:0.2-0.4, preferably 1:0.25-0.35; the molar ratio of component A to component B is 1:12-30, preferably 1:15-20; the molar ratio of component A to component C is 1:2-5, preferably 1:2.5-4.5; preferably, the molar ratio of component A to component D is 1:10-80, preferably 1:35-65.

[0088] According to the present invention, the component A is a neodymium phosphonate compound represented by the following formula (1).

[0089] Formula (1)

[0090] Among them, R a1 , R a2 , R b1 , R b2 , R c1 and R c2Each is independently hydroxy, C1-C20 alkyl or C1-C20 alkoxy, preferably hydroxy, C4-C12 alkyl or C4-C12 alkoxy, more preferably hydroxy, 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-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-undecyloxy or n-dodecyloxy.

[0091] In a preferred embodiment of the present invention, the neodymium phosphonate compound represented by formula (1) is one or more of the following compounds:

[0092] R a1 , R a2 , R b1 , R b2 , R c1 and R c2 A compound which is 2-ethylhexyloxy,

[0093] R a1 , R a2 , R b1 , R b2 , R c1 and R c2 A compound containing 2-ethylhexyl,

[0094] R a1 , R b1 and R c1 The compound is 2-ethylhexyl and R a2 , R b2 and R c2 It is a 2-ethylhexyloxy compound.

[0095] According to the present invention, the alkyl aluminum compound has a wide range of optional types, and the alkyl aluminum compounds commonly used in the art can achieve the purpose of the present invention. According to the present invention, in step 1), the alkyl aluminum compound is preferably selected from trialkyl aluminum and / or dialkyl aluminum hydride, and more preferably one or more of trimethyl aluminum, triethyl aluminum, tripropyl aluminum, tributyl aluminum, tripentylaluminum, trihexylaluminum, triisobutyl aluminum, diethyl aluminum hydride, dipropyl aluminum hydride, dibutyl aluminum hydride and diisobutyl aluminum hydride.

[0096] According to the present invention, the halogenated compound has a wide range of optional types, and the halogenated compounds commonly used in the art can achieve the purpose of the present invention. According to the present invention, in step 1), the halogenated compound is preferably one or more of diethylaluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, monochlorosilane, dichlorosilane, trichlorosilane and silicon tetrachloride.

[0097] According to the present invention, the conjugated diene has a wide range of optional types, and the conjugated dienes commonly used in the art can achieve the purpose of the present invention. According to the present invention, in step 1) and step 2), the conjugated diene is preferably independently a C4-C6 conjugated diene, more preferably one or more of butadiene, isoprene, piperylene 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene and 2,3-dimethylbutadiene, more preferably butadiene and / or isoprene, particularly preferably butadiene.

[0098] According to the present invention, component E is a compound represented by formula (2).

[0099] Formula (2)

[0100] In formula (2), R d1 , R d2 and R d3 Each is independently hydroxy, C4-C12 alkyl or C4-C12 alkoxy, preferably hydroxy, 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-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyloxy, n-octyl, n-nonyl, n-decyl, n-undecyloxy or n-dodecyloxy.

[0101] In a preferred embodiment of the present invention, the compound represented by formula (2) is di(2-ethylhexyl) phosphate (R d1 and R d2 is 2-ethylhexyloxy and R d3 is a hydroxyl compound), 2-ethylhexyl phosphate mono-2-ethylhexyl ester (R d1 is 2-ethylhexyl, R d2 is 2-ethylhexyloxy and R d3 is a hydroxyl compound) and di-(2-ethylhexyl)phosphonic acid (R d1 and R d2 is 2-ethylhexyl and R d3 is a hydroxyl compound) or more.

[0102] According to the present invention, the purpose of the present invention can be achieved according to the above technical scheme. Taking into account the conversion rate of conjugated dienes and the properties of the obtained polymer, for the present invention, preferably, in step 2), the polymerization unit includes at least 2 polymerization reactors connected in series, further preferably includes 3-10 polymerization reactors connected in series, and more preferably includes 3-5 polymerization reactors connected in series.

[0103] The polymerization reactor can be operated with an external jacket for temperature control. For example, the temperature in the polymerization reactor can be controlled within a desired range by 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 mixtures and frozen brine, preferably frozen brine.

[0104] It is easy for a person skilled in the art to understand that in order to continuously use the rare earth catalyst prepared in step 1) for the production of the polymer in step 2), that is, to achieve continuous integration of catalyst preparation and conjugated diene polymerization, the fourth coil is connected in series with the first polymerization reactor according to the flow direction of the materials, so that the rare earth catalyst obtained by contact in step 1) is directly fed into the polymerization unit.

[0105] According to the present invention, preferably, the method of the present invention further comprises: under polymerization reaction conditions, before the conjugated diene, the rare earth catalyst and the inert organic solvent are continuously fed into the polymerization unit for contact, the conjugated diene, the rare earth catalyst and the inert organic solvent are premixed. The optional range of the premixing conditions is relatively wide, and the premixing temperature and time can be reasonably selected according to the flow rates of the conjugated diene, the rare earth catalyst and the inert organic solvent. Generally, the premixing for 5-20 minutes at room temperature (5-40°C) can make the above three components uniformly mixed. The premixing can be carried out in a traditional kettle premixer. In this case, according to the flow direction of the material, the fourth coil is connected in series with the kettle premixer, and the kettle premixer is connected in series with the first polymerization reactor, so as to realize the continuous integration of the preparation of the catalyst and the polymerization of the conjugated diene. The specific implementation process is well known to those skilled in the art and will not be repeated here.

[0106] According to the present invention, the purpose of the present invention can be achieved according to the above technical scheme. In order to further optimize the continuous polymerization method of the present invention, for the present invention, 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, and more preferably 10-60°C; the contact time in each polymerization reactor is independently 10-90min, preferably 20-80min, and more preferably 30-60min; the total contact time in each polymerization reactor does not exceed 300min, preferably 90-180min, and more preferably 110-150min.

[0107] According to the present invention, the amount of the rare earth catalyst can be appropriately selected based on the principle of industrial economy. Generally speaking, the smaller the amount of the catalyst, the larger the molecular weight of the obtained polymer product, but the slower the polymerization rate; the larger the amount of the catalyst, the faster the polymerization rate, but it will increase the cost and may also increase the ash content in the obtained polymer product, which is not conducive to the subsequent treatment or application of the product. Therefore, considering various factors comprehensively, 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;

[0108] According to the present invention, the second organic solvent can be any existing organic solvent that does not react chemically with the reactants and reaction products. Generally, the organic solvents in step 1) and step 2) can be the same or different, and each can be independently selected from one or more of aromatic hydrocarbons, saturated alkanes and cycloalkanes; specifically, each can be independently selected from one or more of benzene, toluene, ethylbenzene, xylene (including o-xylene, m-xylene and p-xylene), pentane and its isomers (e.g., n-pentane, isopentane, methylcyclopentane, 2-methylpentane and 3-methylpentane), hexane and its isomers (e.g., n-hexane, cyclohexane), heptane and its isomers (e.g., n-heptane), octane and its isomers (e.g., n-octane), cyclohexane and raffinate oil. The amount of the organic solvent can be selected conventionally in the art without particular limitation. 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 -1mol / L to ensure the smooth progress of the mixing and aging process and obtain a rare earth catalyst with higher activity. In step 2), based on 100 parts by weight of the conjugated diene, the amount of the second organic solvent can be 400-900 parts by weight, which not only allows the polymerization reaction to proceed smoothly, but also can obtain a higher yield.

[0109] 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, a terminator can be added to the polymerization reaction system to inactivate the active polymer chain. The type and amount of the terminator can be conventionally selected in the art and are not particularly limited, as long as the terminator can inactivate the polymer chain with active end groups. Generally, the terminator can be selected from water, C1-C6 aliphatic alcohol, C4-C 12 One or more of aliphatic carboxylic acids, aromatic polyhydroxy compounds. The aromatic polyhydroxy compound refers to a compound in which at least two hydrogen atoms on the benzene ring are replaced by hydroxyl groups. Preferably, the terminator is one or more of water, methanol, ethanol, isopropanol and 2,6-di-tert-butylhydroquinone. The present invention does not specifically limit the amount of the terminator, as long as the amount of the terminator can inactivate the active species in the polymer product, which will not be repeated here.

[0110] The continuous polymerization method of the present invention is 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, such as Figure 1 As shown, first, in the presence of a first organic solvent, component A and component E are pumped into a first static mixer 1 by metering pumps, enter a homogenizer 2 for homogenization, enter a first coil 3, and then enter a first buffer tank 4 to obtain a first mixture, then the first mixture, component D and component B are pumped into a second static mixer 5 by metering pumps, enter a second coil 6, and then enter a second buffer tank 7 to obtain a second mixture, then the second mixture and component C are pumped into a third static mixer 8 by metering pumps, enter a third coil 9, and then enter a third buffer tank 10 to obtain a third mixture, and then the third mixture is continuously aged in a fourth coil 11 to obtain a rare earth catalyst; the obtained rare earth catalyst is continuously fed into a polymerization unit 12. Wherein, the polymerization reactors used in the static mixer and the polymerization unit are both controlled by passing a circulating medium into the external jacket, thereby realizing the preparation of the catalyst and the continuous production of conjugated diene polymerization.

[0111] The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

[0112] In the following examples and comparative examples, the homogenizer used was an F22Z online homogenizer manufactured by Fluke.

[0113] In the following examples and comparative examples, the microstructure of the synthesized polymer products was measured using a German Bruker Tensor27 mid-infrared spectrometer and a German Bruker 400 MHz nuclear magnetic resonance spectrometer, and the solvent was deuterated chloroform; the Mooney viscosity was measured using an automatic Mooney viscometer (SMV-300, purchased from Shimadzu Corporation), and the test temperature was 100°C.

[0114] 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 polymer to the weight of monomer entering the polymerization section, that is,

[0115]

[0116] In the following examples and comparative examples, neodymium phosphonate is represented by formula (1), R a1 , R a2 , R b1 , R b2 , R c1 and R c2 The phosphonic acid is di(2-ethylhexyl) phosphate (purchased from J&K).

[0117] Example 1

[0118] This example is used to illustrate the continuous polymerization method provided by the present invention.

[0119] according to Figure 1 The flowchart shown is aggregated

[0120] (1) Preparation of rare earth catalysts

[0121] Under nitrogen protection, a metering pump was used to continuously add a 0.03 mol / L neodymium phosphonate / hexane solution and a 0.1 mol / L phosphonic acid / hexane solution to the first static mixer (purchased from Qidong Great Petrochemical Equipment Company, sx model, the same below). The flow rates were controlled at 400 mL / h and 40 mL / h, respectively. The operating temperature was 30°C and the mixture was sent to a homogenizer with a stirring linear speed of 16 m / s and a residence time of 4 min. The mixture then entered the first coil (with a pipe diameter of 6 mm) with a residence time of 8 h and a linear speed of 0.26 cm / min. After the first buffer tank is filled with materials, a metering pump is used to continuously add a 0.55 mol / L diisobutylaluminum hydride / hexane solution and a 1.2 mol / L butadiene hexane solution to the second static mixer (purchased from Qidong Gelait Petrochemical Equipment Company sx model, the same below), with flow rates of 487 mL / h and 500 mL / h, respectively, and an operating temperature of 40°C. The residence time in the second coil (with a diameter of 6 mm) is 20 min, and the linear velocity is 0.55 cm / min. After the second buffer tank is filled with materials, a metering pump is used to continuously add a 0.12 mol / L diethylaluminum chloride / hexane solution to the third static mixer (purchased from Qidong Gelait Petrochemical Equipment Company sx model, the same below), with a flow rate of 280 mL / h, an operating temperature of 60°C, a residence time in the third coil (with a diameter of 6 mm) of 120 min, and a linear velocity of 0.72 cm / min. The material filled the third buffer tank and then entered the fourth coil (with a diameter of 6 mm) with a residence time of 12 hours and a linear velocity of 0.72 cm / min to obtain a light yellow-green rare earth catalyst;

[0122] (2) Preparation of butadiene rubber

[0123] The rare earth catalyst, butadiene (mol ratio of Nd to Bd is 3.9×10 -5 ) and hexane (wherein, the flow rates of butadiene and hexane are 16.5kg / h and 120kg / h respectively) are continuously fed into a kettle premixer for premixing at room temperature to obtain a mixed reaction raw material, and the mixed reaction raw material is continuously fed into four polymerization reactors connected in series. The residence time of the materials in the four polymerization reactors is 40min. The jacket of each reactor is passed through a circulating medium, and the kettle temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 40°C, 45°C, 55°C, and 60°C, respectively. After the continuous production runs smoothly, a certain amount of glue solution is taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal, and drying, it is analyzed and tested. The results of 24 consecutive samplings are as follows: the monomer conversion rate is 90-95%, the content of the cis-1,4-structure of the product is 97.3-97.5%, and the weight-average molecular weight is 2.97×10 5 -3.16×10 5, the molecular weight distribution index is 1.79-2.04. In the final mixed product, the content of cis-1,4-structure is 97.3%, and the weight average molecular weight is 3.04×10 5 , the molecular weight distribution index is 1.89.

[0124] Example 2

[0125] This example is used to illustrate the continuous polymerization method provided by the present invention.

[0126] according to Figure 1 The flowchart shown is aggregated

[0127] (1) Preparation of rare earth catalysts

[0128] Under nitrogen protection, a 0.03 mol / L neodymium phosphonate / hexane solution and a 0.1 mol / L phosphonic acid / hexane solution were continuously added to the first static mixer using a metering pump, and the flow rates were controlled to be 420 mL / h and 35 mL / h, respectively. The operating temperature was 35°C, and the mixture was sent to a homogenizer with a stirring line speed of 15 m / s and a residence time of 5 min. After that, the mixture entered the first coil (with a diameter of 6 mm) for a residence time of 6 h and a line speed of 0.27 cm / min. After the first buffer tank was filled with materials, a 0.55 mol / L diisobutylaluminum hydride / hexane solution and a 1.2 mol / L butadiene hexane solution were continuously added to the second static mixer using a metering pump, and the flow rates were 453 mL / h and 550 mL / h, respectively. The operating temperature was 20°C, and the mixture entered the second coil (with a diameter of 6 mm) for a residence time of 45 min and a line speed of 0.59 cm / min. After the second buffer tank is filled with materials, a metering pump is used to continuously add a 0.12 mol / L diethylaluminum chloride / hexane solution to the third static mixer, with a flow rate of 280 mL / h and an operating temperature of 50°C. The residence time in the third coil (with a diameter of 6 mm) is 150 min and the linear velocity is 0.76 cm / min. After the materials fill the third buffer tank, the residence time in the fourth coil (with a diameter of 6 mm) is 15 hours and the linear velocity is 0.76 cm / min, and a light yellow-green rare earth catalyst is obtained;

[0129] (2) Preparation of butadiene rubber

[0130] The rare earth catalyst, butadiene (mol ratio of Nd to Bd is 4.12×10 -5) and hexane (wherein, the flow rates of butadiene and hexane are 16.5kg / h and 120kg / h respectively) are continuously fed into a kettle premixer for premixing at room temperature to obtain a mixed reaction raw material, and the mixed reaction raw material is continuously fed into four polymerization reactors connected in series. The residence time of the materials in the four polymerization reactors is 40min. The jacket of each reactor is passed through a circulating medium, and the kettle temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 35°C, 45°C, 55°C, and 60°C, respectively. After the continuous production runs smoothly, a certain amount of glue solution is taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal, and drying, it is analyzed and tested. The results of 24 consecutive samplings are as follows: the monomer conversion rate is 89-93%, the content of the cis-1,4-structure of the product is 96.5-97.6%, and the weight-average molecular weight is 2.56×10 5 -2.91×10 5 , the molecular weight distribution index is 2.02-2.31. In the final mixed product, the content of cis-1,4-structure is 97.1%, and the weight average molecular weight is 2.73×10 5 , the molecular weight distribution index is 2.12.

[0131] Example 3

[0132] This example is used to illustrate the continuous polymerization method provided by the present invention.

[0133] according to Figure 1 The flowchart shown is aggregated

[0134] (1) Preparation of rare earth catalysts

[0135] Under nitrogen protection, a 0.03 mol / L neodymium phosphonate / hexane solution and a 0.1 mol / L phosphonic acid / hexane solution were continuously added to the first static mixer using a metering pump, and the flow rates were controlled to be 300 mL / h and 30 mL / h, respectively, and the operating temperature was 50°C. The mixture was sent to a homogenizer with a stirring line speed of 18 m / s and a residence time of 4 min. After that, the mixture entered the first coil (with a diameter of 6 mm) for a residence time of 5 h and a line speed of 0.19 cm / min. After the first buffer tank was filled with materials, a 0.55 mol / L diisobutylaluminum hydride / hexane solution and a 1.2 mol / L butadiene hexane solution were continuously added to the second static mixer using a metering pump, and the flow rates were 486 mL / h and 570 mL / h, respectively, and the operating temperature was 30°C. The mixture entered the second coil (with a diameter of 6 mm) for a residence time of 25 min and a line speed of 0.53 cm / min. After the second buffer tank is filled with materials, a metering pump is used to continuously add a 0.12 mol / L diethylaluminum chloride / hexane solution to the third static mixer, with a flow rate of 280 mL / h, an operating temperature of 45°C, and a residence time of 180 min and a linear velocity of 0.70 cm / min in the third coil (with a diameter of 6 mm). After the materials fill the third buffer tank, they enter the fourth coil (with a diameter of 6 mm) with a residence time of 24 hours and a linear velocity of 0.70 cm / min to obtain a light yellow-green rare earth catalyst;

[0136] (2) Preparation of butadiene rubber

[0137] The rare earth catalyst, butadiene (mol ratio of Nd to Bd is 3.31×10 -5 ) and hexane (wherein, the flow rates of butadiene and hexane are 14.7kg / h and 120kg / h respectively) are continuously fed into a kettle premixer for premixing at room temperature to obtain a mixed reaction raw material, and the mixed reaction raw material is continuously fed into four polymerization reactors connected in series. The residence time of the materials in the four polymerization reactors is 40min. The jacket of each reactor is passed through a circulating medium, and the kettle temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 40°C, 45°C, 55°C, and 60°C, respectively. After the continuous production runs smoothly, a certain amount of glue solution is taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal, and drying, it is analyzed and tested. The results of 24 consecutive samplings are as follows: the monomer conversion rate is 88-92%, the content of the cis-1,4-structure of the product is 96.2-98.1%, and the weight average molecular weight is 2.66×10 5 -2.98×10 5 , the molecular weight distribution index is 2.11-2.32. In the final mixed product, the content of cis-1,4-structure is 96.9%, and the weight average molecular weight is 2.82×105 , the molecular weight distribution index is 2.21.

[0138] Example 4

[0139] This example is used to illustrate the continuous polymerization method provided by the present invention.

[0140] according to Figure 1 The flowchart shown is aggregated

[0141] (1) Preparation of rare earth catalysts

[0142] Under nitrogen protection, a metering pump is used to continuously add a 0.03 mol / L neodymium phosphonate / hexane solution and a 0.1 mol / L phosphonic acid / hexane solution to the first static mixer, and the flow rates are controlled to be 400 mL / h and 40 mL / h, respectively, and the operating temperature is 35°C. The mixture is sent to a homogenizer, and the stirring line speed of the homogenizer is 19 m / s, and the residence time is 3 min. After that, the mixture enters the first coil (with a diameter of 6 mm) and the residence time is 6 h, and the line speed is 0.26 cm / min. After the first buffer tank is filled with materials, a metering pump is used to continuously add a 0.55 mol / L diisobutylaluminum hydride / hexane solution and a 1.2 mol / L butadiene hexane solution to the second static mixer, and the flow rates are 5320 mL / h and 620 mL / h, respectively, and the operating temperature is 50°C. The mixture enters the second coil (with a diameter of 6 mm) and the residence time is 7 min, and the line speed is 0.63 cm / min. After the second buffer tank is filled with materials, a metering pump is used to continuously add a 0.12 mol / L diethylaluminum chloride / hexane solution to the third static mixer, with a flow rate of 280 mL / h and an operating temperature of 55°C. The residence time in the third coil (with a diameter of 6 mm) is 120 min and the linear velocity is 0.79 cm / min. After the materials fill the third buffer tank, they are placed in the fourth coil (with a diameter of 6 mm) for 18 hours and a linear velocity of 0.79 cm / min to obtain a light yellow-green rare earth catalyst;

[0143] (2) Preparation of butadiene rubber

[0144] The rare earth catalyst, butadiene (mol ratio of Nd to Bd is 3.93×10 -5) and hexane (wherein, the flow rates of butadiene and hexane are 16.5kg / h and 120kg / h respectively) are continuously fed into a kettle premixer for premixing at room temperature to obtain a mixed reaction raw material, and the mixed reaction raw material is continuously fed into four polymerization reactors connected in series. The residence time of the materials in the four polymerization reactors is 40min. The jacket of each reactor is passed through a circulating medium, and the kettle temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 40°C, 45°C, 55°C, and 60°C, respectively. After the continuous production runs smoothly, a certain amount of glue solution is taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal, and drying, it is analyzed and tested. The results of 24 consecutive samplings are as follows: the monomer conversion rate is 86-91%, the content of the cis-1,4-structure of the product is 96.5-98.1%, and the weight-average molecular weight is 2.98×10 5 -3.34×10 5 , the molecular weight distribution index is 2.18-2.59. In the final mixed product, the content of cis-1,4-structure is 97.2%, and the weight average molecular weight is 3.16×10 5 , the molecular weight distribution index is 2.32.

[0145] Example 5

[0146] This example is used to illustrate the continuous polymerization method provided by the present invention.

[0147] according to Figure 1 The flowchart shown is aggregated

[0148] (1) Preparation of rare earth catalysts

[0149] Under nitrogen protection, a 0.04 mol / L neodymium phosphonate / hexane solution and a 0.15 mol / L phosphonic acid / hexane solution were continuously added to the first static mixer using a metering pump, and the flow rates were controlled to be 410 mL / h and 30 mL / h, respectively. The operating temperature was 35°C, and the mixture was sent to a homogenizer with a stirring line speed of 12 m / s and a residence time of 6 min. After that, the mixture entered the first coil (with a diameter of 6 mm) for a residence time of 6 h and a line speed of 0.26 cm / min. After the first buffer tank was filled with materials, a 0.55 mol / L diisobutylaluminum hydride / hexane solution and a 1.5 mol / L butadiene hexane solution were continuously added to the second static mixer using a metering pump, and the flow rates were 524 mL / h and 550 mL / h, respectively. The operating temperature was 50°C, and the mixture entered the second coil (with a diameter of 6 mm) for a residence time of 20 min and a line speed of 0.58 cm / min. After the second buffer tank is filled with materials, a metering pump is used to continuously add a 0.12 mol / L diethylaluminum chloride / hexane solution to the third static mixer, with a flow rate of 280 mL / h and an operating temperature of 55°C. The residence time in the third coil (with a diameter of 6 mm) is 120 min and the linear velocity is 0.74 cm / min. After the materials fill the third buffer tank, they are placed in the fourth coil (with a diameter of 6 mm) for 18 hours and a linear velocity of 0.74 m / min to obtain a light yellow-green rare earth catalyst;

[0150] (2) Preparation of butadiene rubber

[0151] The rare earth catalyst, butadiene (mol ratio of Nd to Bd is 5.65×10 -5 ) and hexane (wherein, the flow rates of butadiene and hexane are 16.5kg / h and 120kg / h respectively) are continuously fed into a kettle premixer for premixing at room temperature to obtain a mixed reaction raw material, and the mixed reaction raw material is continuously fed into four polymerization reactors connected in series. The residence time of the materials in the four polymerization reactors is 40min. The jacket of each reactor is passed through a circulating medium, and the kettle temperatures of the first polymerization reactor, the second polymerization reactor, the third polymerization reactor, and the fourth polymerization reactor are controlled at 40°C, 45°C, 55°C, and 60°C, respectively. After the continuous production runs smoothly, a certain amount of glue solution is taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal, and drying, it is analyzed and tested. The results of 24 consecutive samplings are as follows: the monomer conversion rate is 80-91%, the content of the cis-1,4-structure of the product is 96.3-98.1%, and the weight-average molecular weight is 2.55×10 5 -2.86×10 5 , the molecular weight distribution index is 2.23-2.68. In the final mixed product, the content of cis-1,4-structure is 97.4%, and the weight average molecular weight is 2.76×10 5, the molecular weight distribution index is 2.43.

[0152] Comparative Example 1

[0153] This example serves to illustrate a reference continuous polymerization process.

[0154] Butadiene rubber was prepared according to the method of Example 1, except that the coil was replaced by a reactor. After the continuous production was running smoothly, a certain amount of rubber solution was taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal and drying, analysis and testing were performed. The results of 24 consecutive samplings were: the monomer conversion rate was 79-86%, the content of cis 1,4-structure of the product was 96.2-98.3%, and the weight average molecular weight was 2.33×10 5 -3.23×10 5 , the molecular weight distribution index is 3.53-4.24. In the final mixed product, the content of cis-1,4-structure is 97.2%, and the weight average molecular weight is 2.87×10 5 , the molecular weight distribution index is 3.72.

[0155] Comparative Example 2

[0156] This example serves to illustrate a reference polymerization process.

[0157] (1) Preparation of rare earth catalysts

[0158] The rare earth catalyst was prepared according to the order of addition, the molar ratio of each component, the reaction temperature and the reaction time in Example 1, except that an intermittent preparation method was adopted. Specifically, under nitrogen protection, 12.3L of 0.03mol / L neodymium phosphonate / hexane solution, 1.23L of 0.1mol / L phosphonic acid / hexane solution, 15L of 0.55mol / L diisobutylaluminum monohydrogen / hexane solution and 15.4L of 1.2mol / L butadiene / hexane solution were added to a 100L reactor and reacted at 40°C for 20min. Then, after the reactor temperature was raised to 60°C, 8.5L of 0.12mol / L diethylaluminum monochloride / hexane solution was added to the reactor and reacted for 2 hours and 20 minutes to obtain a homogeneous rare earth catalyst.

[0159] (2) Preparation of butadiene rubber

[0160] The rare earth catalyst (flow rate of 1.71 L / h) and butadiene monomer (flow rate of 16.5 kg / h) (mol ratio of Nd to Bd of 3.93×10 -5) and hexane (120 kg / h) were fed into the polymerization section, and the continuous polymerization method was the same as in Example 1. After the continuous production was running smoothly, a certain amount of glue solution was taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal and drying, analysis and testing were performed. The results of 24 consecutive samplings were: the monomer conversion rate was 63-81%, the content of cis-1,4-structure of the product was 96.0-97.7%, and the weight average molecular weight was 2.21×10 5 -3.48×10 5 , the molecular weight distribution index is 2.68-5.18. The content of cis-1,4-structure of the final mixed product is 97.2%, and the weight average molecular weight is 2.63×10 5 , the molecular weight distribution index is 4.76.

[0161] Comparative Example 3

[0162] This example serves to illustrate a reference continuous polymerization process.

[0163] Butadiene rubber was prepared according to the method of Example 1, except that the stirring speed of the homogenizer was 6 m / s. After the continuous production was stable, a certain amount of rubber solution was taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal and drying, analysis and testing were performed. The results of 24 consecutive samplings were: the monomer conversion rate was 82-89%, the content of cis-1,4-structure of the product was 96.1-98.4%, and the weight average molecular weight was 2.53×10 5 -3.15×10 5 , the molecular weight distribution index is 2.43-2.84. In the final mixed product, the content of cis-1,4-structure is 97.1%, and the weight average molecular weight is 2.86×10 5 , the molecular weight distribution index is 2.67.

[0164] Comparative Example 4

[0165] This example serves to illustrate a reference continuous polymerization process.

[0166] Butadiene rubber was prepared according to the method of Example 1, except that the stirring speed of the homogenizer was 22 m / s, and the catalyst became turbid. After the continuous production was stable, a certain amount of rubber solution was taken from the outlet of the fourth reactor every 4 hours, and after termination, solvent removal and drying, analysis and testing were performed. The results of 24 consecutive samplings were: the monomer conversion rate was 53-61%, the content of cis-1,4-structure of the product was 96.1-97.6%, and the weight average molecular weight was 2.65×10 5 -3.33×10 5 , the molecular weight distribution index is 4.83-5.54. In the final mixed product, the content of cis-1,4-structure is 96.9%, and the weight average molecular weight is 2.91×10 5, the molecular weight distribution index is 5.21.

[0167] From the comparison of Examples 1-5 and Comparative Examples 1-2, it can be seen that the continuous polymerization method provided by the present invention can make the molecular weight and distribution of the obtained polymer relatively stable, with less fluctuation and relatively stable performance. From the comparison of Examples 1-4 and 5, it can be seen that when the linear velocity through the first coil is 0.25-0.4cm / min, the linear velocity through the second coil is 0.7-0.95cm / min, the linear velocity through the third coil is 0.9-1.25cm / min, and the linear velocity through the fourth coil is 0.9-1.25cm / min, the performance of the obtained polymer is 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.

[0168] In addition, from the comparison between Example 1 and Comparative Examples 3-4, it can be seen that the homogenizing stirring linear speed needs to be in the range of 10-20 m / s, which can make the molecular weight and distribution of the obtained polymer more stable, less volatile, and more stable in performance.

[0169] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for continuous polymerization of conjugated dienes, characterized in that: The Method The following steps are included: 1) In the presence of a first organic solvent, component A and component E are respectively sent to a first mixing unit for first mixing, then enter a homogenizer for homogenization, enter a first coil for first aging, and then enter a first buffer unit to obtain a first mixture; the first mixture, component D and component B are respectively sent to a second mixing unit for second mixing, then enter a second coil for second aging, and then enter a second buffer unit to obtain a second mixture; the second mixture and component C are respectively sent to a third mixing unit for third mixing, then enter a third coil for third aging, and then enter a third buffer unit to obtain a third mixture; the third mixture is sent to a fourth coil for fourth aging to obtain a rare earth catalyst; 2) under polymerization reaction conditions, the conjugated diene, the rare earth catalyst obtained in step 1) and the second organic solvent are continuously fed into the polymerization unit for contact, Wherein, the homogenization stirring linear speed of the homogenization treatment is 8-20m / s, 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 a compound represented by formula (2), Formula (1) Formula (2) In formula (1), R a1 , R a2 , R b1 , R b2 , R c1 and R c2 Each is 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 Each is 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 homogenization treatment conditions include: homogenization stirring linear speed of 10-20 m / s, residence time of 3-6 min; Preferably, the first aging conditions include: temperature of 10-60°C, residence time in the first coil of 2-60h, preferably 5-10h, and linear speed in the first coil of 0.1-50cm / min, preferably 0.3-0.5cm / min.

3. The method according to claim 1, wherein: The second mixing conditions include: a temperature of 0-50°C, preferably 20-40°C; Preferably, the second aging conditions include: temperature of 0-50°C, residence time in the second coil of 5-120 min, preferably 20-45 min, and linear speed in the second coil of 0.1-50 cm / min, preferably 0.5-1 cm / min.

4. The method according to claim 1, wherein: The third mixing conditions include: a temperature of 10-80°C, preferably 50-70°C; Preferably, the conditions for the third aging include: a temperature of 10-80° C., a residence time in the third coil of 30-180 min, preferably 90-150 min, and a linear speed in the third coil of 0.1-50 cm / min, preferably 0.6-1.5 cm / min.

5. The method according to claim 1, wherein: The fourth aging conditions include: a temperature of 0-40° C., a residence time in the fourth coil of 1-48 hours, preferably 12-24 hours, and a linear speed in the fourth coil of 0.1-50 cm / min, preferably 0.6-1.5 cm / min.

6. The method according to any one of claims 1 to 5, wherein: 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.

7. The method according to claim 1, wherein: The molar ratio of the component A to the component E is 1:0.2-0.4; Preferably, the molar ratio of component A to component B is 1:12-30; Preferably, the molar ratio of component A to component C is 1:2-5; Preferably, the molar ratio of the component A to the component D is 1:10-80.

8. The method according to any one of claims 1 to 5, wherein: In formula (1), R a1 , R a2 , R b1 , R b2 , R c1 and R c2 each independently represents hydroxy, C4-C12 alkyl or C4-C12 alkoxy, preferably hydroxy, 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-hexyl, 2-methylhexyl, 2-ethylhexyl, n-heptyloxy, n-octyl, n-nonyl, n-decyl, n-undecyloxy or n-dodecyloxy; In formula (2), R d1 , R d2 and R d3 each independently represents hydroxy, 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-hexyl, 2-methylhexyl, 2-ethylhexyl, 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 A compound which is 2-ethylhexyloxy, R a1 , R a2 , R b1 , R b2 , R c1 and R c2 A compound containing 2-ethylhexyl, R a1 , R b1 and R c1 The compound is 2-ethylhexyl and R a2 , R b2 and R c2 A compound which is 2-ethylhexyloxy; Preferably, the compound represented by formula (2) is one or more of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester and di-(2-ethylhexyl)phosphonic acid.

9. The method according to any one of claims 1 to 5, wherein: The alkyl aluminum compound is selected from trialkyl aluminum and / or dialkyl aluminum hydride; Preferably, the alkyl aluminum compound is one or more of trimethyl aluminum, triethyl aluminum, tripropyl aluminum, tributyl aluminum, tripentylaluminum, trihexylaluminum, triisobutylaluminum, diethylaluminum hydride, dipropylaluminum hydride, dibutylaluminum hydride and diisobutylaluminum hydride; The halogenated compound is one or more of diethylaluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, monochlorosilane, dichlorosilane, trichlorosilane and silicon tetrachloride.

10. The method according to any one of claims 1 to 5, wherein: The conjugated diene is one or more of butadiene, isoprene, piperylene, 1,3-pentadiene, 1,3-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 used can be such that, based on the neodymium phosphonate compound represented by formula (1), the concentration of the rare earth catalyst is 1×10 -4 -1mol / L.

11. The method according to any one of claims 1 to 5, wherein: The amount of the rare earth catalyst used is 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 the conjugated diene, the amount of the second organic solvent is 400-900 parts by weight.

12. The method according to any one of claims 1 to 5, wherein: In step 2), the polymerization unit comprises at least 2 polymerization reactors connected in series, preferably 3-10 polymerization reactors connected in series, and more preferably 3-5 polymerization reactors connected in series.

13. The method according to claim 12, wherein: 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 fed into the polymerization unit.

14. The method according to claim 12 or 13, 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, and more preferably 10-60°C; the contact time in each polymerization reactor is independently 10-90min, preferably 20-80min, and more preferably 30-60min; the total contact time in each polymerization reactor does not exceed 300min, preferably 90-180min, and more preferably 110-150min.

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