JP2017128711A - Method for producing conjugated diene polymer utilizing parallel polymerization reactor - Google Patents

Abstract

The present invention relates to a method for producing a conjugated diene polymer which complements the shortcomings of the existing batch type and continuous type and can exhibit desired physical properties when producing a rubber composite material.
Two or more batch or continuous polymerization reactors are arranged in parallel to independently polymerize linear and branched structures, and the resulting reaction product of anionic solution polymerization is obtained. It includes a step of mixing the product into a solution and producing a product.
[Selection] Figure 1

Description

  The present invention uses a parallel polymerization process technique to produce a low molecular weight (linear (hereinafter also referred to as “linear”), using two or more reactors during the production of an anion solution polymerization conjugated diene polymer. A high molecular weight linear structure and a high molecular weight branched (hereinafter also referred to as “branched”) structure, respectively, a low molecular weight linear structure through a solution blend, a high molecular weight linear structure, It is a process technology that can produce rubbers with excellent cold flow and wear characteristics with low Mooney viscosity by adjusting the content of high molecular weight branch structure.

  The solution styrene butadiene rubber (SSBR) obtained by solution polymerization generally uses an organic metal catalyst having carbon anionic property as an initiator, and the molecular weight and molecular weight distribution are characteristic of the polymerization method called anionic polymerization. Of course, not only the polymer micro-structure, but also the macro-structure can be adjusted, and when used for tire treads, it is a rubber material that improves braking performance on wet roads and improves the fuel ratio. is there. More specifically, the solution styrene butadiene rubber produced by solution polymerization is roughly classified into a batch type and a continuous type. The batch-type process is a method using a single reactor, in which a solvent, a raw material, and a randomizing agent are charged into the reactor, an initiator is charged, polymerization proceeds, the reaction is terminated, and a solution of styrene butadiene is obtained. A rubber solution is produced. The continuous process, which is the other method, is a process of cleaning the reactor by continuously adding solvent, raw material, randomizing agent and initiator to the front end of two or more reactors connected in series using a metering pump. This is a method for continuously producing a solution of a solution of styrene butadiene rubber without using any solvent. The continuous reaction has advantages in terms of productivity and production unit cost compared to the batch reaction. On the other hand, the batch method is inferior in productivity and production cost compared with the continuous method, but has advantages over the continuous method such as control of the molecular structure and production of a polymer having a narrow molecular weight distribution. However, rubber composites made from batch solution styrene butadiene rubber have lower molecular weight than continuous solution styrene butadiene rubber, and showed poor performance in terms of mechanical strength and wear. In recent years, not only the fuel ratio and braking performance on wet road surfaces, but also the wear performance that leads to the life of the tire has become important, and it is necessary to supplement the previously used solution styrene butadiene rubber. Specifically, in batch reaction, terminal modification and coupling reaction are simultaneously performed in one reactor, and the terminal modification conjugation is performed by adjusting the coupling ratio and terminal modification ratio, and using different types of terminal modifiers. There are limits to the production of diene polymers.

  In the case of a product produced through an existing batch process, an organic metal catalyst such as alkyl lithium having carbon anionic property is used as an initiator. The polymerization initiator is characterized by being a polymerization initiator that can be expressed by the following chemical formula.

        R (Li) x

  In the chemical formula, R is a hydrocarbyl group having 2 to 8 carbon atoms per R group, and x is an integer of 1 to 4. A modified conjugated polymer is produced by polymerizing a solution styrene butadiene rubber whose terminal is activated with an anion using the initiator, and additionally using a compound capable of simultaneously acting as a coupling agent and a modifier. To do. In general, commercially produced solution-polymerized conjugated diene rubbers contain less than 60% of divalent or higher branched structures, and among them, trivalent or higher branched structures exceed 10% of the total content. Absent. When manufacturing a tire tread with such a modified conjugated diene system, the fuel ratio performance and the braking performance on wet road surfaces can be ensured, but the molecular weight of the product manufactured in a batch type is 200,000 to 600,000 g / mol, When the composite material is manufactured with silica, the wear characteristics that affect the tire life are significantly reduced compared to the existing emulsion styrene butadiene rubber and carbon black composite material. Products produced through a continuous process can be used to complement the wear characteristics, but unlike the batch process, the continuous process controls the precise molecular structure and molecular distribution, and adjusts the terminal denaturation rate. Therefore, the fuel ratio performance and the braking performance on wet roads are inferior to those of the batch system.

  Conventionally, a conjugated diene polymer polymerization method uses a single batch reactor, and a conjugated diene polymer whose initial terminal is activated by an anion to ensure molecular structure and mechanical properties during polymerization of the conjugated diene polymer. After the production of the diene polymer, a coupling agent or a modifier is additionally added. Such a polymerization method has a feature that only one kind of product is produced in one reactor, and the conjugated diene polymer thus produced is coupled with a molecular weight of a linear polymer. Independent control of the molecular weight of the branched polymer is not possible. For these reasons, the performance that appears after the production of a rubber composite material using an inorganic filler is limited in terms of mechanical properties (tensile strength, elongation rate, hardness), wear performance, and the like.

  Unlike the existing batch polymerization process, the present invention uses two or more reactors and a large number of storage tanks to polymerize products with controlled molecular microstructure and macrostructure in each reactor, and then in solution. The present invention relates to a method for producing a conjugated diene polymer, which blends at a constant ratio and complements the shortcomings of the existing batch type and continuous type, and can exhibit desired physical properties when producing a rubber composite material.

  The present invention relates to a method for producing a solution-polymerized conjugated diene polymer produced by using a parallel polymerization process technique, and more particularly, two or more reactions during the production of an anion solution polymerized conjugated diene polymer. A low molecular weight linear structure, a high molecular weight linear structure, and a high molecular weight branch structure using a vessel, respectively, and then a low molecular weight linear structure, a high molecular weight linear structure, and a high molecular weight branch through solution blending. It is a process technology that can produce rubbers with excellent cold flow and wear properties at low Mooney viscosities by adjusting the shape and content.

The method for producing a conjugated diene polymer according to the present invention includes the following steps.
(1) The molecular weight is adjusted by controlling the fine molecular structure and the terminal modification is performed, and the conjugated diene polymers different from each other in the coupling method and efficiency are manufactured by controlling the macromolecular structure in different polymerization reactors. Storing in different storage tanks; and
(2) A prepolymerized and stored conjugated diene polymer is blended in a desired ratio, and finally a heavy molecular weight can be adjusted while maintaining the same or low Mooney viscosity through the process of commercialization. It is divided into the stages of obtaining coalescence.

  In the initiator presented in the step (1), not only alkyllithium, alkylsodium and alkylpotassium, but also anionic polymerization characteristics of solution styrene butadiene rubber (SSBR) using an initiator having a specific anion form It can be used to produce various structures using polymerization techniques such as molecular weight adjustment, terminal modification, and coupling. In step (2), the blend ratio is adjusted to adjust the terminal modification rate, Mooney viscosity, and weight average molecular weight, as well as the processability, tensile strength, viscoelasticity, and wear performance of rubber composites. There are advantages that can be done.

  The additional terminal modifier or coupling agent in the step (1) can be any generally capable of reacting with an anion, and the molecular weight increases depending on the number of functional groups or the structure of the polymer is deformed. Is obtained. In general, tin series, alkoxysilane, or silyl halide can be used, and a compound containing a glycidyl group is also used.

For example, the tin series includes diphenyltin dichloride, dibutyltin dichloride, dihexyltin dichloride, dioctyltin dichloride, phenyltin trichloride, butyltin trichloride, octyltin trichloride, tetrachlorotin, tetramethoxytin, tetraethoxytin, tetrapropoxytin The alkoxysilane series is dimethyldimethoxysilane, diethyldimethoxysilane, dipropyldimethoxysilane, dibutyldimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, methyltriethoxysilane , Ethyltriethoxysilane, propyltriethoxysilane, butyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, etc. It is.
The silyl halide series is diphenyldichlorosilane, dihexyldichlorosilane, dioctyldichlorosilane, dibutyldichlorosilane, dimethyldichlorosilane, methyltrichlorosilane, phenyltrichlorosilane, hexyltrichlorosilane, octyltrichlorosilane, butyltrichlorosilane, methyltrichlorosilane, tetrachlorosilane Etc. are used.

Compounds containing glycidyl groups are 4,4'-methylenebis (N, N-diglycidylaniline), N, N-diglycidyl-4-glycidoxyaniline, N, N-diglycidylaniline, N, N, N '-N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminodiphenylmethane and the like are used.
In addition, an aminosilane derivative containing an ester group such as tertiary butyl acrylate or ((triacryloxypropyl) trimethoxysilane) is used.
The terminal modifiers and coupling agents exemplified above can be used alone or in admixture of two or more. Illustrating compounds is not intended to limit the structure, but can be anything that can react with the terminal end having anionic activity, such as tin series, alkoxysilane series, silyl halide series, glycidyl series It is.

  In the method for producing a conjugated diene polymer according to the present invention, the solvent used in the process is produced by using two or more batch-type or continuous polymerization reactors in the form of a solution in the polymerization step (1). The hydrogen solvent is n-hexane, n-heptane, cyclohexane, isooctane, methylcyclopentane, benzene, toluene, xylene, tetrahydrofuran, etc., which can be used alone or in combination of two or more. . A monomer is added so that it may become 5 to 50 weight% in the said hydrocarbon solvent. Preferably it is added at a level of 15 to 35% by weight. If it is less than 5% by weight, the polymerization time may be long or the reaction may be difficult, and if it is 50% by weight or more, the solution viscosity will increase, making it difficult to control the molecular weight and heat of reaction, and uniform stirring during polymerization will be difficult.

In the method for producing a conjugated diene polymer according to the present invention, in the step (1), the reaction temperature may vary depending on the solvent, and the polymerization is generally possible at 10 to 160 ° C. The microstructure can be changed depending on the polymerization temperature, and the polymerization temperature can be adjusted according to the purpose.
The batch reactor according to the present invention is a continuous stirred tank reactor (CSTR), and the impala type is paddle, anchor, helical ribbon, double-helical ribbon, Use one or more of the turbines.
The conjugated diene polymer according to the present invention is neodymium produced by solution polymerization, although the catalyst is different from isoprene rubber (IR) and butadiene rubber (BR), which can additionally perform anion polymerization in addition to styrene butadiene rubber (SSBR). Diene rubbers such as butadiene rubber (NdBR) can also be produced through the above process.

  The present invention relates to a method for producing a solution-polymerized conjugated diene polymer produced by using a parallel polymerization process technique, and more particularly, two or more reactions during the production of an anion solution polymerized conjugated diene polymer. The low molecular weight linear structure, the high molecular weight linear structure, and the high molecular weight branch form are respectively produced using a vessel, and then the contents of the low molecular weight linear structure and the high molecular weight branch form through solution blending are adjusted. Thus, it is possible to produce a rubber having excellent cold flow and wear characteristics at a low Mooney viscosity.

It is the schematic of the manufacturing process of a conjugated diene type polymer.

  Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrative purposes only, and the present invention is not limited to these examples.

[Production example]
[Production of linear styrene-butadiene polymer]
In a 2 m ³ volume autoclave reactor, 34 kg of styrene, 136 kg of 1,3-butadiene, and 830 kg of hexane were added, and 2 L of tetramethylethylenediamine (TMEDA) was added. Here, n-BuLi was added, and a linear SBR having a molecular weight (Mw) of about 120,000 or 150,000 g / mol was polymerized through a polymerization reaction. Thereafter, ethanol as a reaction terminator was added to terminate the polymerization, and 0.2 wt% of an antioxidant I-1076 was added to the polymer to produce a linear SBR solution. The produced linear SBR solution was transferred to a separate storage tank for storage.

[Production of branched styrene-butadiene polymer]
In a 2 m ³ volume autoclave reactor, 34 kg of styrene, 126 kg of 1,3-butadiene and 830 kg of hexane were added, and 2 L of tetramethylethylenediamine (TMEDA) was added, and then the reactor temperature was raised to 50 ° C. while rotating with a stirrer. Here, n-BuLi was put and polymerized to polymerize linear SBR having Mw of about 300,000 or 350,000 g / mol. After 10 minutes had passed since the reaction temperature reached the maximum temperature, 10 kg of butadiene was added to replace the terminal end of the polymer with butadiene active anions for 5 minutes. Here, 3-glycidoxypropyltrimethoxysilane was added at a ratio of 1/3 with respect to the number of moles of n-BuLi and allowed to react for 10 minutes. After the reaction, ethanol was added to terminate the polymerization, and an antioxidant I-1076 was added in an amount of 0.2 wt% to the polymer to produce a branched SBR solution. The produced branched SBR solution was transferred to a separate storage tank for storage.

[Production of blended final products]
After the linear SBR and the branch SBR manufactured in advance are transferred to the blend tank in various proportions of linear and branch based on the total solid content of 100 parts by weight, the mixture is stirred for 30 minutes to prepare a uniform mixed solution. Utilizing existing stripper and product process, polymer blend products were manufactured. Detailed examples are described in detail in the following examples.

The characteristics of the composite using the conjugated diene polymer and the inorganic filler produced were analyzed through the following method.
1. Analysis of polymer microstructure The microstructure of the polymerized polymer was confirmed using Bruker's 400 MHz 1H-NMR.
2. Measurement of molecular weight Molecular weight was measured by connecting two polystyrene 5 μm mixed-C columns from PLgel in series, a polystyrene standard sample (molecular weight 5000 g / mol) together with a polymer, and a solvent using tetrahydrofuran (THF). A refractive index detector (RI) was used as a detector.
3. Tensile Experiment A vulcanized test piece was manufactured using a universal testing machine (LLOYD UTM) in accordance with ASTM 412 tensile test method by producing a c-type dumbbell.
4). Mooney viscosity The Mooney viscosity of the conjugated diene polymer itself was measured using a Mooney viscometer (Alpha technology) at 100 ° C. with reference to ML (1 + 4).
5. Cold flow
The cold flow of the conjugated diene polymer itself is the method presented by Chevron Philips, and the sample is manufactured to a size of 29.0 (D) x 12.5 (T) mm, under a load of 216 g at 65 ° C. The deformation was measured after 1 hour.
6). DIN Abrasion Test A cylinder with a diameter of 10 mm and a height of 10 mm was made from a vulcanized specimen and measured according to ASTM D 5963 DIN abrasion test method using a DIN ABRASION TESTER. .

Example 1
1) linear styrene - styrene autoclave reactor producing 2m ³ volume of butadiene polymer 34 kg, 1,3-butadiene 136 kg, placed hexane 830 kg, tetramethylethylenediamine (TMEDA) After 2L turned stirrer reactor temperature The temperature was raised to 50 ° C. while turning. Here, n-BuLi was added, and a linear SBR having an Mw of 150,000 g / mol was polymerized through a polymerization reaction. After the reaction, ethanol was added to stop the polymerization, the polymer was transferred to a separate storage tank, and 0.2 wt% of the antioxidant I-1076 was added to the polymer to produce a linear SBR solution. did.

2) branch-shaped styrene-butadiene polymer prepared 2m ³ volume autoclave reactor styrene 34 kg, 1,3-butadiene 126 kg, placed hexane 830 kg, tetramethylethylenediamine (TMEDA) After 2L charged, the reactor temperature The temperature was raised to 50 ° C. while rotating with a stirrer. Here, n-BuLi was put and polymerized to polymerize linear SBR having Mw of 300,000 g / mol. After 10 minutes had passed since the reaction temperature reached the maximum temperature, 10 kg of butadiene was added to replace the terminal end of the polymer with butadiene active anions for 5 minutes. Here, 3-glycidoxypropyltrimethoxysilane was added at a ratio of 1/3 with respect to the number of moles of n-BuLi and allowed to react for 10 minutes. After the reaction, ethanol was added to stop the polymerization, the polymer was transferred to a separate storage tank, and I-1076, an antioxidant, was added to the polymer in an amount of 0.2 wt% to form a branched SBR solution. Manufactured.

3) Production of blend SBR After mixing 1) and 2) produced in advance at a ratio of 1) 20 parts by weight (40 kg) and 2) 80 parts by weight (160 kg), based on 100 parts by weight of the total solid content, The mixture was stirred for 30 minutes to produce a uniform mixed solution, and hexane as a solvent was removed using a steam stripper. Most of the water is removed from the resulting solid using a dehydrator, residual water is removed using a hot air dryer, and then transferred and packaged in units of 35 kg using a baler to provide a conjugated diene polymer. A blended product was produced.

Example 2
The same procedure as in Example 1 was performed except that the mixing ratio of the linear and branched shapes was changed to 40:60 weight ratio in the production process of 3) blend SBR of Example 1.
Example 3
Example 1 3) The same procedure as in Example 1 except that the blend ratio of linear and branched was changed to 60:40 weight ratio in the production process of blend SBR.
Example 4
The same procedure as in Example 1 was performed except that the mixing ratio of the linear and branched shapes was changed to 80:20 weight ratio in the production process of 3) blend SBR of Example 1.

Example 5
1) linear end-modified styrene - butadiene polymers prepared 2m ³ volume autoclave reactor styrene 34 kg, 1,3-butadiene 136 kg, placed hexane 830 kg, tetramethylethylenediamine (TMEDA) After 2L charged, reactor temperature The temperature was raised to 50 ° C. while rotating with a stirrer. Here, n-BuLi was added, and a linear SBR having an Mw of 120,000 g / mol was polymerized through a polymerization reaction. After the reaction, ethanol was added to stop the polymerization, the polymer was transferred to a separate storage tank, and 0.2 wt% of the antioxidant I-1076 was added to the polymer to produce a linear SBR solution. did.

2) branch-shaped styrene-butadiene polymer prepared 2m ³ volume autoclave reactor styrene 34 kg, 1,3-butadiene 126 kg, placed hexane 830 kg, tetramethylethylenediamine (TMEDA) After 2L charged, the reactor temperature The temperature was raised to 50 ° C. while rotating with a stirrer. Here, n-BuLi was put and polymerized to polymerize linear SBR having Mw of 350,000 g / mol. After 10 minutes had passed since the reaction temperature reached the maximum temperature, 10 kg of butadiene was added to replace the terminal end of the polymer with butadiene active anions for 5 minutes. Here, 3-glycidoxypropyltrimethoxysilane was added at a ratio of 1/3 with respect to the number of moles of n-BuLi and allowed to react for 10 minutes. After the reaction, ethanol was added to stop the polymerization, the polymer was transferred to a separate storage tank, and I-1076, an antioxidant, was added to the polymer in an amount of 0.2 wt% to form a branched SBR solution. Manufactured.

3) Production of blend SBR After mixing 1) and 2) produced in advance at a ratio of 1) 20 parts by weight (40 kg) and 2) 80 parts by weight (160 kg), based on 100 parts by weight of the total solid content, The mixture was stirred for 30 minutes to produce a uniform mixed solution, and hexane as a solvent was removed using a steam stripper. Most of the water is removed from the resulting solid using a dehydrator, residual water is removed using a hot air dryer, and then transferred and packaged in units of 35 kg using a baler to provide a conjugated diene polymer. A blended product was produced.

Example 6
Example 5 3) The same procedure as in Example 5 except that the mixing ratio of the linear and branched shapes was changed to 40:60 weight ratio in the production process of the blend SBR.
Example 7
Example 5 3) The same as Example 5 except that the blend ratio of linear and branched was changed to 60:40 weight ratio in the production process of blend SBR.
Example 8
Example 5 3) The same as Example 5 except that the blend ratio of linear and branched was changed to 80:20 weight ratio in the production process of blend SBR.

Comparative Example 1
In a 2 m ³ volume autoclave reactor, 34 kg of styrene, 126 kg of 1,3-butadiene and 830 kg of hexane were added, and 2 L of tetramethylethylenediamine (TMEDA) was added. Here, 0.85 mol of n-BuLi was added for a polymerization reaction, and after 10 minutes had passed since the reaction temperature reached the maximum temperature, 10 kg of butadiene was added, and the terminal end of the polymer was blocked for butadiene activity for 5 minutes. Replaced with ions. Here, 0.24 mol of 3-glycidoxypropyltrimethoxysilane (GPTMS) was added and reacted for 10 minutes. After the reaction, ethanol was added to terminate the polymerization, the polymer was transferred to a separate storage tank, and I-1076, an antioxidant, was added at 0.2 wt% to the polymer. Thereafter, hexane as a solvent was removed using a steam stripper. Most of the water is removed from the resulting solid using a dehydrator, residual water is removed using a hot air dryer, and then transferred and packaged in units of 35 kg using a baler to provide a conjugated diene polymer. A blended product was produced.
Comparative Example 2
The same operation as in Comparative Example 1 was conducted except that the coupling agent in Comparative Example 1 was changed to Bis (methyldimethoxysilylpropyl) -N-methylamine.

Experimental Example Kneading of Polymer and Inorganic Material and Physical Property Measurement Experiment The rubber composition of the polymer obtained above was kneaded using Thermo Scientific's Haake Polylab OS Rheodrive, and a Banbury rotor was used. The polymers obtained in the examples and comparative examples were blended with the compositions shown in Table 1 below.
Blending proceeded in two stages. Kneading is 75% in the first kneading, and polymer, filler (carbon black), oil, zinc oxide (ZnO), stearic acid, antioxidant (6-PPD) at a rotor speed of 60 rpm. ) To control the temperature and obtain a primary rubber composition at 150 to 160 ° C. In the second kneading, the blend was cooled to room temperature, and sulfur, DPG (Diphenyl Guanidine) and CBS (N-cyclohexyl-2-benzothiazole sulfonamide) were added and kneaded at 90 ° C. or lower for 5 minutes.
Vulcanized rubber is produced by vulcanizing the blended rubber at 160 ° C with a T90 + 5min press.

  The polymers and polymer blends prepared according to the present invention were analyzed and evaluated for performance and are shown in Tables 2-7 below.

The solution styrene butadiene rubber produced through the process of polymerizing the linear and branched structures independently, mixing them into a solution, and commercializing them, compared to the solution styrene butadiene rubber produced in the existing batch system (batch) It was confirmed that the cold flow was low, the storage stability was excellent, the trivalent or higher branch shape was included, and the mechanical strength (tensile strength, modulus) and wear performance were improved. .

Claims (4)

  A method for producing a conjugated diene polymer, wherein two or more batch type or continuous type polymerization reactors are arranged in parallel, and linear and branched structures are polymerized independently. A method for producing a conjugated diene polymer comprising a step of mixing a reaction product of the anionic solution polymerization in a solution state to produce a product.   The conjugated diene polymer according to claim 1, wherein the branched structure content of the tri- or higher valent structure is 15 parts by weight or more based on 100 parts by weight of the total solid content. Method.   The conjugated diene polymer is any one of styrene butadiene rubber (SSBR), isoprene rubber (IR), butadiene rubber (BR), and neodymium butadiene rubber (NdBR). A process for producing a conjugated diene polymer. The batch reactor is a continuous stirred tank reactor (CSTR), and the impala type is paddle, anchor, helical ribbon, double-helical ribbon, turbine ( 2. The method for producing a conjugated diene polymer according to claim 1, wherein the batch reactor uses one or more of turbine).