阅读说明：本技术 一种合成无规溶聚丁苯橡胶的方法 (Method for synthesizing random solution polymerized styrene butadiene rubber ) 是由 徐炜 秦雄芬 王雪 王世朝 杨洪友 李维兵 骆宝进 于 2019-08-22 设计创作，主要内容包括：本发明涉及聚合物合成领域,公开了一种合成无规溶聚丁苯橡胶的方法,该方法包括：在惰性溶剂和有机锂引发剂存在下,将丁二烯单体和苯乙烯单体形成的混合物料进行间歇聚合反应,其中,控制所述混合物料的进料速度,使得所述混合物料在(30-55)min加完,并且,所述间歇聚合反应的引发温度为(20-50)℃。根据本发明提供的方法得到的溶聚丁苯橡胶具有无规分布的特点,从而使得其应用性能更为优异；而且不必须加入调节剂或是必须采用高温聚合工艺,从而可以节约生产成本。(The invention relates to the field of polymer synthesis, and discloses a method for synthesizing random solution polymerized styrene-butadiene rubber, which comprises the following steps: performing batch polymerization on a mixed material formed by butadiene monomer and styrene monomer in the presence of an inert solvent and an organic lithium initiator, wherein the feeding speed of the mixed material is controlled so that the mixed material is added in (30-55) min, and the initiation temperature of the batch polymerization is (20-50) DEG C. The solution-polymerized styrene-butadiene rubber obtained by the method provided by the invention has the characteristic of random distribution, so that the application performance of the solution-polymerized styrene-butadiene rubber is more excellent; and no regulator is needed to be added or a high-temperature polymerization process is needed, so that the production cost can be saved.)

1. A method of synthesizing a random solution-polymerized styrene-butadiene rubber, the method comprising: performing batch polymerization on a mixed material formed by butadiene monomer and styrene monomer in the presence of an inert solvent and an organic lithium initiator, wherein the feeding speed of the mixed material is controlled so that the mixed material is added in (30-55) min, and the initiation temperature of the batch polymerization is (20-50) DEG C.

2. The method of claim 1, wherein the feed rate of the mixed feed is controlled such that the butadiene monomer and the styrene monomer are added over (40-50) min.

3. The process of claim 1 or 2, wherein the initiation temperature of the batch polymerization reaction is (25-35) ° c.

4. The method according to any one of claims 1 to 3, wherein the butadiene monomer and the styrene monomer are used in a weight ratio of (3.5 to 6): 1.

5. the method according to any one of claims 1-3, wherein the method further comprises: after the batch polymerization reaction is completed, a coupling agent is added to the reaction system to perform a coupling reaction.

6. The process according to claim 5, wherein the coupling agent is used in a molar ratio to the organolithium initiator, calculated as lithium element, of (0.05-0.45): 1, preferably (0.15-0.30): 1.

7. the method of claim 5 or 6, wherein the method further comprises: carrying out termination reaction on the system obtained after the coupling reaction is carried out, and adding an anti-aging agent into the system;

preferably, the anti-aging agent is selected from at least one of anti-aging agent 264, anti-aging agent 1076, anti-aging agent 1010 and anti-aging agent 1520.

8. The process according to any one of claims 1 to 7, wherein the inert solvent is selected from at least one of cyclohexane, n-hexane, n-heptane, cyclopentane.

9. The process according to any one of claims 1 to 7, wherein the inert solvent is present in a weight ratio of (5-9): 1 of cyclohexane and n-hexane.

10. The method of any one of claims 1-9, wherein the method further comprises: controlling the feed rate of the mixed materials so that the peak temperature of the batch polymerization reaction is not higher than 90 ℃; preferably not higher than 85 deg.c.

Technical Field

The invention relates to the field of polymer synthesis, in particular to a method for synthesizing random solution polymerized styrene-butadiene rubber.

Background

After decades of development, the solution polymerized styrene-butadiene rubber has become a synthetic rubber for the tread of a radial tire of a high-performance car, which is widely applied to tire production lines at home and abroad.

However, the application of solution polymerized styrene-butadiene rubber in the field of all-steel tires is in the beginning stage at present. Compared with the traditional emulsion polymerized styrene-butadiene rubber, the solution polymerized styrene-butadiene rubber can adjust the molecular configuration proportion such as the content of styrene and vinyl in a larger range, can reduce the self terminal group of the molecular chain of the sizing material through molecular modification technologies such as molecular coupling, terminal functionalization and the like, and improves the hysteresis heat-generating property of the sizing material. Moreover, the interaction between the rubber material and the filler or other compounding agents can be improved by grafting various types of special groups, so that the special processing performance is obtained, the application performance of the rubber material in practical use is optimized, the balance of rolling resistance and wet-skid resistance of the rubber material applied to tread rubber is improved, and a car tire product with higher grade, more environmental protection and safety is obtained.

From the application of the solution polymerized styrene butadiene rubber products in the current domestic and foreign markets, the random solution polymerized styrene butadiene rubber with low vinyl and low styrene content is a product with characteristics, and can be applied to the tire tread rubber with special requirements on rolling resistance and wear resistance.

At present, the synthesis method of the low-styrene low-vinyl random solution polymerized styrene-butadiene rubber is generally to add a structure regulator or carry out polymerization under high temperature conditions. For example, CN102344530A uses a two-component regulator to synthesize a high vinyl solution-polymerized styrene-butadiene rubber with random distribution.

Disclosure of Invention

The invention aims to provide a novel method for synthesizing randomly distributed solution polymerized styrene-butadiene rubber without adding a regulator or carrying out polymerization reaction at high temperature on the premise of ensuring the monomer conversion rate to be 100 percent so as to obtain the random solution polymerized styrene-butadiene rubber with low block content of styrene structural units.

In order to achieve the above object, the present invention provides a method for synthesizing a random solution-polymerized styrene-butadiene rubber, the method comprising: performing batch polymerization on a mixed material formed by butadiene monomer and styrene monomer in the presence of an inert solvent and an organic lithium initiator, wherein the feeding speed of the mixed material is controlled so that the mixed material is added in (30-55) min, and the initiation temperature of the batch polymerization is (20-50) DEG C.

The invention can obtain the low-styrene low-vinyl solution polymerized butadiene styrene rubber with random distribution by specifically controlling the feeding time without adding a regulator or carrying out polymerization reaction at high temperature, and has the characteristic of 100 percent of monomer conversion rate.

Further, the method of the invention also has the advantage of saving production cost.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As previously described, the present invention provides a method for synthesizing a random solution-polymerized styrene-butadiene rubber, the method comprising: performing batch polymerization on a mixed material formed by butadiene monomer and styrene monomer in the presence of an inert solvent and an organic lithium initiator, wherein the feeding speed of the mixed material is controlled so that the mixed material is added in (30-55) min, and the initiation temperature of the batch polymerization is (20-50) DEG C.

In order to make the block content of styrene in the random solution-polymerized styrene-butadiene rubber obtained by the method of the present invention lower, it is preferable to control the feeding rate of the mixed material so that the butadiene monomer and the styrene monomer are added up in (40 to 50) min.

Preferably, the initiation temperature of the batch polymerization reaction is (25-35) ° c. That is, the batch polymerization in the process of the present invention can obtain a low styrene low vinyl solution-polymerized styrene-butadiene rubber having a random distribution when it is carried out at an initiation temperature of (25 to 35) ° C.

Preferably, the butadiene monomer and the styrene monomer are used in a weight ratio of (3.5-6): 1.

according to a preferred embodiment, the method further comprises: after the batch polymerization reaction is completed, a coupling agent is added to the reaction system to perform a coupling reaction.

In the present invention, the completion of the batch polymerization reaction is marked by the fact that the contents of both the butadiene monomer and the styrene monomer in the reaction system are less than 1% by weight. The above content test can be carried out, for example, by nuclear magnetism or the like.

In the present invention, the organolithium initiator is preferably added at once.

The present invention is not particularly limited in particular kind of the coupling agent, and various kinds of coupling agents conventionally used in the art may be used, and one of the coupling agents is exemplified in the examples of the present invention, and those skilled in the art should not be construed as limiting the present invention.

Preferably, the molar ratio of the coupling agent to the organolithium initiator calculated on the lithium element is (0.05-0.45): 1, more preferably (0.15-0.30): 1.

the specific type of organolithium initiator is not particularly limited in the present invention, and those skilled in the art can perform various organolithium initiators conventionally used in the art.

According to another preferred embodiment, the method further comprises: and (3) carrying out termination reaction on the system obtained after the coupling reaction, and adding an anti-aging agent into the system.

The specific operation for carrying out the termination reaction in the present invention is not particularly limited, and the termination reaction can be carried out by various methods which are conventional in the art, for example, by introducing an appropriate amount of isopropyl alcohol into the system.

Preferably, the anti-aging agent is selected from at least one of anti-aging agent 264, anti-aging agent 1076, anti-aging agent 1010 and anti-aging agent 1520.

According to the present invention, the antioxidant may be used in an amount conventionally used in the art. For example, the antioxidant may be used in an amount of 0.005 to 2% by weight, preferably 0.1 to 0.5% by weight, based on the weight of the random solution-polymerized styrene-butadiene rubber.

According to the present invention, after the anti-aging agent is added, the random solution polymerized styrene-butadiene rubber can be precipitated from the solution by methods such as purification and precipitation, centrifugal separation, filtration, decantation, hot water coagulation, etc., and the solvent in the reaction system can also be removed by a gas stripping method, which is known to those skilled in the art and will not be described herein again.

Preferably, the inert solvent is at least one selected from cyclohexane, n-hexane, n-heptane and cyclopentane.

In order to make the block content of styrene in the random solution-polymerized styrene-butadiene rubber obtained by the method of the present invention lower, the inert solvent is preferably a solvent having a weight ratio of (5-9): 1 of cyclohexane and n-hexane.

Furthermore, it is well known to those skilled in the art that trace amounts of water may be present in the solvent. However, since water is a terminator of anionic polymerization and can terminate the chain extension reaction by proton transfer, it is preferable to remove water from the solvent in the present invention in order to smoothly proceed the polymerization reaction. The water removal method can be to add a water removal agent into the solvent. The type of water scavenger is well known to those skilled in the art and may be, for example, a 5A molecular sieve available from gangkangkangyu chemical company, ltd.

According to a particularly preferred embodiment, the method of the invention further comprises: controlling the feed rate of the mixed materials so that the peak temperature of the batch polymerization reaction is not higher than 90 ℃; more preferably not higher than 85 deg.c. That is, the process of the present invention need not be carried out at elevated temperatures.

The peak temperature described herein represents the highest temperature tested during a batch polymerization reaction.

Also, the process of the present invention is preferably carried out under pressure conditions greater than atmospheric pressure. The pressure referred to in the following description of the present invention indicates gauge pressure unless otherwise specified.

According to a particularly preferred embodiment, the method of the invention comprises:

performing batch polymerization on a mixed material formed by butadiene monomers and styrene monomers in the presence of an inert solvent and an organic lithium initiator, wherein the feeding speed of the mixed material is controlled so that the mixed material is added in (30-55) min, and the initiation temperature of the batch polymerization is (20-50) DEG C; after the batch polymerization reaction is completed, adding a coupling agent into the reaction system to perform a coupling reaction; and then, carrying out termination reaction on the system obtained after the coupling reaction, and adding an anti-aging agent into the system.

The random solution polymerized styrene-butadiene rubber obtained by the method of the present invention has a number average molecular weight of usually 10 to 30 ten thousand and a molecular weight distribution of 1.01 to 1.05.

Also, the block content of the styrene structural unit in the random solution-polymerized styrene-butadiene rubber obtained by the method of the present invention is usually (0.1 to 0.5) wt%; the nonblock content of styrene structural units is generally (12-18)% by weight; the content of vinyl structural units is generally (10-20)% by weight.

The present invention will be described in detail below by way of examples. In the following examples, various raw materials used are commercially available ones unless otherwise specified.

In the following examples, the number average molecular weight and the molecular weight distribution of the polymer product were determined by Gel Permeation Chromatography (GPC) of model LC-10AT from Shimadzu corporation, using tetrahydrofuran as the mobile phase, narrow distribution polystyrene as the standard, and a test temperature of 25 ℃.

In the following examples, the solvent was soaked with 5A molecular sieves (phi. 3X 5, from Daliankang chemical Co., Ltd., previously baked at 500 ℃ for 5 hours) for 1 week before the solvent was applied.

In the following examples, the conversions measured are all of the total monomer conversion and are calculated as: conversion ═ 100% by weight (weight of initial total monomers-weight of remaining total monomers)/weight of initial total monomers

Example 1

2500g of a mixed solvent (cyclohexane and n-hexane in a weight ratio of 88: 12) and 20ml of an n-butyllithium solution (n-butyllithium concentration: 0.1437mol/L) were sequentially charged into a 5-liter polymerization vessel under a nitrogen atmosphere. The temperature is raised to 30 ℃, and the reaction pressure is 0.1 MPa. 56g of styrene and 317g of butadiene were mixed and slowly fed into the polymerization vessel, the feed rate being controlled so that the mixture of styrene and butadiene was added within 45 minutes and the reaction continued for 15 minutes after the addition, the peak temperature being 75 ℃ and the reaction pressure being 0.30 MPa. A sample was taken 10 minutes after the peak temperature to determine that the conversion reached 100%, at which time the reaction pressure was 0.18 MPa. Then 10ml (0.043mol/L) of silicon tetrachloride solution is added into the reaction kettle to continue the reaction, and after the reaction is carried out for 10 minutes, 0.5ml of isopropanol is added to stop the reaction. After stirring for 15 minutes, 3.0g of the antioxidant 2, 6-di-tert-butyl-p-methylphenol was added.

And (3) coagulating the glue solution by water vapor, and drying by an open mill to obtain a polymerization product. The microstructure of the product was measured and is shown in Table 1.

Example 2

2500g of a mixed solvent (cyclohexane and n-hexane in a weight ratio of 85: 15) and 20ml of an n-butyllithium solution (n-butyllithium concentration: 0.1437mol/L) were sequentially charged into a 5-liter polymerization vessel under a nitrogen atmosphere. The temperature is raised to 25 ℃, and the reaction pressure is 0.1 MPa. 67g of styrene and 306g of butadiene were mixed and slowly fed into the polymerization kettle, the feed rate was controlled, the mixture of styrene and butadiene was added within 40 minutes, and the reaction continued for 10 minutes after the addition, at a peak temperature of 73 ℃ and a reaction pressure of 0.30 MPa. A sample was taken 10 minutes after the peak temperature to determine that the conversion reached 100%, at which time the reaction pressure was 0.18 MPa. Then 10ml (0.043mol/L) of silicon tetrachloride solution is added into the reaction kettle to continue the reaction, and after the reaction is carried out for 10 minutes, 0.5ml of isopropanol is added to stop the reaction. After stirring for 15 minutes, 3.0g of the antioxidant 2, 6-di-tert-butyl-p-methylphenol was added.

And (3) coagulating the glue solution by water vapor, and drying by an open mill to obtain a polymerization product. The microstructure of the product was determined and is shown in Table 1.

Example 3

2500g of a mixed solvent (cyclohexane and n-hexane in a weight ratio of 90: 10) and 20ml of an n-butyllithium solution (n-butyllithium concentration: 0.1437mol/L) were sequentially charged into a 5-liter polymerization vessel under a nitrogen atmosphere. The temperature is raised to 35 ℃, and the reaction pressure is 0.1 MPa. 75g of styrene and 298g of butadiene are mixed and slowly fed into the polymerization kettle, the feeding speed is controlled, the mixture of styrene and butadiene is added within 50 minutes, and the reaction pressure is 0.30MPa when the peak temperature of 70 ℃ is reached after the reaction lasts for 8 minutes. A sample was taken 10 minutes after the peak temperature to determine that the conversion reached 100%, at which time the reaction pressure was 0.18 MPa. Then 10ml (0.043mol/L) of silicon tetrachloride solution is added into the reaction kettle to continue the reaction, and after the reaction is carried out for 10 minutes, 0.5ml of isopropanol is added to stop the reaction. After stirring for 15 minutes, 3.0g of the antioxidant 2, 6-di-tert-butyl-p-methylphenol was added.

And (3) coagulating the glue solution by water vapor, and drying by an open mill to obtain a polymerization product. The microstructure of the product was determined and is shown in Table 1.

Example 4

This example was carried out in a similar manner to example 1, except that the mixture of styrene and butadiene in this example was added in 55 minutes. The remaining operating conditions were the same as in example 1.

The microstructure of the product obtained in this example is shown in Table 1.

Example 5

This example was carried out in a similar manner to example 1, except that the mixture of styrene and butadiene in this example was added in 30 minutes. The remaining operating conditions were the same as in example 1.

The microstructure of the product obtained in this example is shown in Table 1.

Comparative example 1

This comparative example was carried out in a similar manner to example 1, except that: styrene and butadiene were all added to the reaction system at the start of the reaction, specifically as follows:

2500g of a mixed solvent (cyclohexane and n-hexane in a weight ratio of 88: 12), 56g of styrene, 317g of butadiene and 20ml of an n-butyllithium solution (n-butyllithium concentration: 0.1437mol/L) were sequentially charged into a 5-liter polymerization vessel under nitrogen protection. The initiation temperature of the polymerization reaction was 30 ℃ and the reaction pressure was 0.3 MPa. After 15 minutes of reaction, a peak temperature of 80 ℃ was reached, at which time the reaction pressure was 0.38 MPa. A sample was taken 10 minutes after the peak temperature to determine that the conversion reached 100%, at which time the reaction pressure was 0.25 MPa. Then 10ml (0.043mol/L) of silicon tetrachloride solution is added into the reaction kettle to continue the reaction, and after the reaction is carried out for 10 minutes, 0.5ml of isopropanol is added to stop the reaction. After stirring for 15 minutes, 3.0g of the antioxidant 2, 6-di-tert-butyl-p-methylphenol was added.

And (3) coagulating the glue solution by water vapor, and drying by an open mill to obtain a polymerization product. The microstructure of the product was determined and is shown in Table 1.

Comparative example 2

This comparative example was carried out in a similar manner to example 2, except that: styrene and butadiene were all added to the reaction system at the start of the reaction, specifically as follows:

2500g of a mixed solvent, 67g of styrene and 306g of butadiene were sequentially charged into a 5-liter polymerization vessel under nitrogen protection, and 20ml of an n-butyllithium solution (the concentration of n-butyllithium was 0.1437mol/L) was added to conduct polymerization. The initiation temperature of the polymerization reaction was 25 ℃ and the reaction pressure was 0.3 MPa. After 15 minutes of reaction, a peak temperature of 79 ℃ was reached, at which point the reaction pressure was 0.36 MPa. A sample was taken 10 minutes after the peak temperature to determine that the conversion reached 100%, at which time the reaction pressure was 0.23 MPa. Then 10ml (0.043mol/L) of silicon tetrachloride solution is added into the reaction kettle to continue the reaction, and after the reaction is carried out for 10 minutes, 0.5ml of isopropanol is added to stop the reaction. After stirring for 15 minutes, 3.0g of the antioxidant 2, 6-di-tert-butyl-p-methylphenol was added.

And (3) coagulating the glue solution by water vapor, and drying by an open mill to obtain a polymerization product. The microstructure of the product was determined and is shown in Table 1.

Comparative example 3

This comparative example was carried out in a similar manner to example 3, except that: styrene and butadiene were all added to the reaction system at the start of the reaction, specifically as follows:

under the protection of nitrogen, 2500g of a mixed solvent, 75g of styrene and 298g of butadiene were sequentially added to a 5-liter polymerization vessel, and 20ml of an n-butyllithium solution (the concentration of n-butyllithium was 0.1437mol/L) was added to conduct polymerization. The polymerization initiation temperature was 35 ℃ and the reaction pressure was 0.3 MPa. After 15 minutes of reaction, a peak temperature of 75 ℃ was reached, at which point the reaction pressure was 0.33 MPa. A sample was taken 10 minutes after the peak temperature to determine that the conversion reached 100%, at which time the reaction pressure was 0.20 MPa. Then 10ml (0.043mol/L) of silicon tetrachloride solution is added into the reaction kettle to continue the reaction, and after the reaction is carried out for 10 minutes, 0.5ml of isopropanol is added to stop the reaction. After stirring for 15 minutes, 3.0g of the antioxidant 2, 6-di-tert-butyl-p-methylphenol was added.

And (3) coagulating the glue solution by water vapor, and drying by an open mill to obtain a polymerization product. The microstructure of the product was determined and is shown in Table 1.

Comparative example 4

This comparative example was conducted in a similar manner to example 1, except that the mixture of styrene and butadiene in this comparative example was added over 60 minutes. The remaining operating conditions were the same as in example 1.

The microstructure of the product obtained in this example is shown in Table 1.

TABLE 1

From the results in table 1, it can be seen that the solution polymerized styrene-butadiene rubber obtained by the method of the present invention has the characteristic of random distribution, and can achieve the excellent effect of low block content of styrene structural units on the premise of ensuring 100% monomer conversion, so that the application performance is more excellent.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.