阅读说明：本技术 一种反式丁戊橡胶的脱挥方法 (Devolatilization method of trans-butyl amyl rubber ) 是由 翟姣 崔丽云 吴文雷 王奇 李兰阁 刘宁 徐继开 于 2020-06-11 设计创作，主要内容包括：本发明提供了一种反式丁戊橡胶的脱挥方法,包括以下步骤：a)将反式丁戊橡胶装入萃取槽,导入超临界流体,将萃取压力升至5MPa～35MPa；所述超临界流体为超临界二氧化碳；b)在上述萃取压力下,通过流动的超临界流体对反式丁戊橡胶进行萃取,分别得到含有挥发分的超临界流体和萃取后的反式丁戊橡胶；c)将步骤b)得到的萃取后的反式丁戊橡胶进行减压,得到脱挥后的反式丁戊橡胶。与现有技术相比,本发明提供的脱挥方法利用超临界流体来脱除反式丁戊橡胶中残留的单体和二聚体,借助超临界流体良好的溶解性和扩散性能,在特定工艺步骤及条件下,实现较好的整体作用,能够增大挥发分在流体中的溶解度并提高挥发分在聚合物中的传质速率,实现深度脱挥。(The invention provides a devolatilization method of trans-butadiene-isoprene rubber, which comprises the following steps: a) loading trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and increasing the extraction pressure to 5-35 MPa; the supercritical fluid is supercritical carbon dioxide; b) extracting the trans-butadiene rubber by flowing supercritical fluid under the extraction pressure to respectively obtain supercritical fluid containing volatile and extracted trans-butadiene rubber; c) decompressing the extracted trans-butadiene rubber obtained in the step b) to obtain the devolatilized trans-butadiene rubber. Compared with the prior art, the devolatilization method provided by the invention utilizes the supercritical fluid to remove the residual monomers and dimers in the trans-butadiene rubber, realizes better integral action under specific process steps and conditions by virtue of good solubility and diffusion performance of the supercritical fluid, can increase the solubility of volatile components in the fluid and improve the mass transfer rate of the volatile components in the polymer, and realizes deep devolatilization.)

1. A devolatilization method of trans-butyl amyl rubber comprises the following steps:

a) loading trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and increasing the extraction pressure to 5-35 MPa; the supercritical fluid is supercritical carbon dioxide;

b) extracting the trans-butadiene rubber by flowing supercritical fluid under the extraction pressure to respectively obtain supercritical fluid containing volatile and extracted trans-butadiene rubber;

c) decompressing the extracted trans-butadiene rubber obtained in the step b) to obtain the devolatilized trans-butadiene rubber.

2. The devolatilization method according to claim 1, characterized in that said trans-butadiene rubber in step a) has a total volatile content of 1% to 5%, an isoprene content of 2000ppm to 6000ppm and a dimer content of 2000ppm to 6000 ppm.

3. The devolatilization method as claimed in claim 1, wherein the loading amount of said extraction vessel in step a) is 100g to 500g, and the temperature is 30 ℃ to 60 ℃.

4. The devolatilization process according to claim 1 wherein said extraction pressure in step a) is comprised between 10MPa and 15 MPa.

5. The devolatilization process according to claim 1, wherein said extraction in step b) is carried out at a temperature ranging from 30 ℃ to 60 ℃, a flow rate ranging from 5kg/h to 8kg/h and a time ranging from 0.5h to 4 h.

6. The devolatilization process according to claim 1, wherein said pressure reduction in step c) is carried out at a pressure of 0MPa for a period of time comprised between 5 and 20 min.

7. The devolatilization process as claimed in any one of claims 1 to 6 wherein said step b) further comprises:

and leading out the obtained supercritical fluid containing the volatile components, and sequentially carrying out reduced pressure separation and adsorption to obtain the purified supercritical fluid.

8. The devolatilization method according to claim 7, wherein said derived frequency is comprised between 3 times/h and 5 times/h.

9. The devolatilization method according to claim 7 wherein said separation under reduced pressure is carried out at a temperature of 40 ℃ to 50 ℃ and a pressure of 4.5MPa to 5 MPa.

10. The devolatilization method according to claim 7, wherein said adsorption is by activated carbon adsorption.

Technical Field

The invention relates to the technical field of polymer devolatilization, in particular to a devolatilization method of trans-butadiene rubber.

Background

Trans-butyl-pentyl rubber is a new generation of functional synthetic rubber material, which has excellent fatigue resistance, wear resistance and low thermal property; meanwhile, the preparation method adopts bulk polymerization, and has the advantages of simple process, low equipment investment, high production capacity, easy serialization, no solvent and low production cost.

The residual volatile components in the polymer not only affect the performance of products, but also cause environmental pollution and threaten the safety and health of people. With the increasing awareness of people on environmental protection, safety and health, devolatilization becomes a key process of post-polymerization treatment in the production process of trans-butadiene-isoprene rubber. The difficulty of diffusion devolatilization is obviously increased because the trans-butyl-pentyl rubber has the characteristics of high viscosity, high elasticity and heat sensitivity. In the process of diffusion devolatilization, the vacuum degree and the temperature are key factors influencing devolatilization; the mass transfer rate of the volatile component determines the devolatilization effect, and the volatile component is fully removed by improving the interface updating speed, the vacuum of the system and the better temperature.

However, in actual production, such as a devolatilization process of the double screw rod, the viscosity of the system is continuously improved along with the continuous reduction of the volatile content, and the high elasticity and high viscosity of the product hinder the interface updating, so that the temperature of the system is increased, the polymer is degraded, and equipment is blocked. If the volatile components are removed by a hot nitrogen purging mode, only the diffusion speed of the volatile components on the surface of the polymer can be increased, and the mass transfer speed of the volatile components in the polymer cannot be increased.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for devolatilizing trans-butadiene rubber, which can increase the solubility of volatile components in a fluid and increase the mass transfer rate of the volatile components in a polymer, thereby realizing deep devolatilization.

The invention provides a devolatilization method of trans-butadiene-isoprene rubber, which comprises the following steps:

a) loading trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and increasing the extraction pressure to 5-35 MPa; the supercritical fluid is supercritical carbon dioxide;

b) extracting the trans-butadiene rubber by flowing supercritical fluid under the extraction pressure to respectively obtain supercritical fluid containing volatile and extracted trans-butadiene rubber;

c) decompressing the extracted trans-butadiene rubber obtained in the step b) to obtain the devolatilized trans-butadiene rubber.

Preferably, the total volatile content of the trans-butadiene rubber in the step a) is 1-5%, the content of isoprene is 2000-6000 ppm, and the content of dimer is 2000-6000 ppm.

Preferably, the loading amount of the extraction tank in the step a) is 100g to 500g, and the temperature is 30 ℃ to 60 ℃.

Preferably, the extraction pressure in step a) is 10MPa to 15 MPa.

Preferably, the extraction temperature in the step b) is 30-60 ℃, the flow rate is 5-8 kg/h, and the time is 0.5-4 h.

Preferably, the pressure of the reduced pressure in the step c) is 0MPa, and the pressure reduction time is 5min to 20 min.

Preferably, the step b) further comprises:

and leading out the obtained supercritical fluid containing the volatile components, and sequentially carrying out reduced pressure separation and adsorption to obtain the purified supercritical fluid.

Preferably, the derived frequency is 3 times/h to 5 times/h.

Preferably, the temperature of the reduced pressure separation is 40-50 ℃, and the pressure is 4.5-5 MPa.

Preferably, the adsorption mode is activated carbon adsorption.

The invention provides a devolatilization method of trans-butadiene-isoprene rubber, which comprises the following steps: a) loading trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and increasing the extraction pressure to 5-35 MPa; the supercritical fluid is supercritical carbon dioxide; b) extracting the trans-butadiene rubber by flowing supercritical fluid under the extraction pressure to respectively obtain supercritical fluid containing volatile and extracted trans-butadiene rubber; c) decompressing the extracted trans-butadiene rubber obtained in the step b) to obtain the devolatilized trans-butadiene rubber. Compared with the prior art, the devolatilization method provided by the invention utilizes the supercritical fluid to remove the residual monomers and dimers in the trans-butadiene rubber, realizes better integral action under specific process steps and conditions by virtue of good solubility and diffusion performance of the supercritical fluid, can increase the solubility of volatile components in the fluid and improve the mass transfer rate of the volatile components in the polymer, and finally achieves the purpose of deep devolatilization. Experimental results show that the devolatilization method provided by the invention can reduce the volatile content of trans-butadiene rubber from 1.11% to 0.1%, reduce the content of monomer isoprene from 3609.79ppm to below 350ppm, and reduce the content of dimer from 4744.80ppm to below 340 ppm.

In addition, the devolatilization method provided by the invention has the advantages of simple process, high efficiency, environmental protection, suitability for heat-sensitive, high-viscosity and high-elasticity polymers, and wide application prospect.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a devolatilization method of trans-butadiene-isoprene rubber, which comprises the following steps:

a) loading trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and increasing the extraction pressure to 5-35 MPa; the supercritical fluid is supercritical carbon dioxide;

b) extracting the trans-butadiene rubber by flowing supercritical fluid under the extraction pressure to respectively obtain supercritical fluid containing volatile and extracted trans-butadiene rubber;

c) decompressing the extracted trans-butadiene rubber obtained in the step b) to obtain the devolatilized trans-butadiene rubber.

Firstly, putting trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and raising the extraction pressure to 5-35 MPa; forming a supercritical extraction system. In the present invention, the total volatile content of the trans-butyl rubber is preferably 1% to 5%, more preferably 1% to 3%; the content of isoprene in the trans-butadiene rubber is preferably 2000ppm to 6000ppm, and more preferably 3000ppm to 4000 ppm; the content of the trans-butadiene rubber dimer is preferably 2000ppm to 6000ppm, and more preferably 2000ppm to 5000 ppm. The source of the trans-butadiene rubber is not particularly limited in the present invention, and industrial products well known to those skilled in the art are used.

In the present invention, the loading amount of the extraction tank is preferably 100g to 500g, more preferably 100 g; the temperature of the extraction tank is preferably 30 ℃ to 60 ℃, and more preferably 35 ℃ to 55 ℃.

In the present invention, the supercritical fluid is supercritical carbon dioxide; the temperature of the supercritical carbon dioxide is preferably 20 ℃ above the critical temperature, more preferably 30 ℃ above the critical temperature; the pressure of the supercritical carbon dioxide is preferably higher than the critical pressure by 5MPa, and more preferably higher than the critical pressure by 7.38 MPa; the source of the supercritical carbon dioxide is not particularly limited in the present invention.

The method comprises the steps of firstly, introducing supercritical fluid to carry out pressurization, and extracting when the supercritical fluid reaches the extraction pressure; namely, under the extraction pressure, the trans-butadiene rubber is extracted by the flowing supercritical fluid, and the supercritical fluid containing volatile matters and the extracted trans-butadiene rubber are respectively obtained. The extraction mode is not particularly limited in the invention, and supercritical kettle type static extraction well known to those skilled in the art is adopted; namely, the supercritical carbon dioxide passes through the polymer in a counter-current manner from bottom to top and is fully contacted with the polymer, thereby achieving better extraction effect.

In the present invention, the extraction pressure is preferably 5 to 35MPa, more preferably 10 to 15 MPa; the extraction temperature is preferably 30-60 ℃, and more preferably 35-55 ℃; the flow rate of the extraction is preferably 5 kg/h-8 kg/h, and the flow rate is the flow rate of the supercritical fluid in the extraction process; the extraction time is preferably 0.5 to 4 hours, more preferably 1 to 2 hours.

In the extraction process, the polymer is plasticized and swelled in the supercritical fluid, the mass transfer rate of the volatile components in the polymer is increased, the solubility of the volatile components in the fluid is increased by adjusting the pressure and the temperature, and the volatile components are removed.

In the present invention, the step b) preferably further comprises:

and leading out the obtained supercritical fluid containing the volatile components, and sequentially carrying out reduced pressure separation and adsorption to obtain the purified supercritical fluid. In the present invention, the volatile component mainly includes isoprene monomer, 1, 4-butadiene monomer, and isoprene homopolymer, 1, 4-butadiene homopolymer, and isoprene and 1, 4-butadiene copolymer.

In the present invention, the derived frequency is preferably 3 times/h to 5 times/h, and more preferably 4 times/h; namely, the supercritical fluid containing volatile components obtained by extraction is led out every 15min, so that the volatile component content in the supercritical fluid subjected to extraction is effectively controlled.

In the present invention, the process of the reduced pressure separation is preferably performed in a separation tank known to those skilled in the art, and a plurality of separation tanks may be used to perform the reduced pressure separation according to different types of objects to be separated, so as to ensure a better separation effect. In the present invention, the temperature of the reduced pressure separation is preferably 40 to 50 ℃; the pressure for the reduced pressure separation is preferably 4.5MPa to 5 MPa.

In the present invention, the adsorption mode is preferably activated carbon adsorption; the purified supercritical fluid can be recycled.

Furthermore, the volatile matter separated under reduced pressure is preferably also subjected to adsorption treatment; the adsorption treatment mode is preferably activated carbon adsorption; the obtained purified volatile matter can be directly discharged.

After the extraction process is finished, the method carries out the last step: reducing the pressure; and decompressing the extracted trans-butadiene rubber to obtain the devolatilized trans-butadiene rubber. In the invention, the decompression process is preferably realized by cutting off the supercritical fluid inlet and slowly adjusting an air valve at the outlet end of the extraction tank; in addition, in the preferred embodiment of the invention, after the pressure of the extraction tank is the same as that of the separation tank, the air valve is closed, and the vent valve is opened, so that the pressure of the extraction tank is reduced to 0MPa, and suck-back is avoided. In the present invention, the pressure of the reduced pressure is preferably 0MPa, and the pressure reduction time of the reduced pressure is preferably 5 to 20min, and more preferably 5 min. By adopting the decompression process, the invention can further devolatilize the extracted trans-butadiene rubber (the polymer is recovered to the original state from the swelling state, and residual volatile components in the polymer can be removed), thereby playing a certain role in realizing deep devolatilization.

The devolatilization method provided by the invention utilizes the supercritical fluid to remove the residual monomers and dimers in the trans-butadiene rubber, realizes better integral action under specific process steps (pressurization, extraction and decompression) and conditions by virtue of good solubility and diffusion performance of the supercritical fluid, can increase the solubility of volatile components in the fluid and improve the mass transfer rate of the volatile components in the polymer, finally achieves the purpose of deep devolatilization, and improves the product quality.

Meanwhile, in the devolatilization process of the supercritical fluid, the devolatilization temperature is lower, and the degradation of polymers and equipment blockage are effectively avoided; the supercritical carbon dioxide selected by the invention has the advantages of mild critical conditions, environmental protection, safety, no pollution, no additive, low price, easy obtainment and the like; in addition, the invention can realize the recycling of the supercritical carbon dioxide.

The invention provides a devolatilization method of trans-butadiene-isoprene rubber, which comprises the following steps: a) loading trans-butyl-pentyl rubber into an extraction tank, introducing supercritical fluid, and increasing the extraction pressure to 5-35 MPa; the supercritical fluid is supercritical carbon dioxide; b) extracting the trans-butadiene rubber by flowing supercritical fluid under the extraction pressure to respectively obtain supercritical fluid containing volatile and extracted trans-butadiene rubber; c) decompressing the extracted trans-butadiene rubber obtained in the step b) to obtain the devolatilized trans-butadiene rubber. Compared with the prior art, the devolatilization method provided by the invention utilizes the supercritical fluid to remove the residual monomers and dimers in the trans-butadiene rubber, realizes better integral action under specific process steps and conditions by virtue of good solubility and diffusion performance of the supercritical fluid, can increase the solubility of volatile components in the fluid and improve the mass transfer rate of the volatile components in the polymer, and finally achieves the purpose of deep devolatilization. Experimental results show that the devolatilization method provided by the invention can reduce the volatile content of trans-butadiene rubber from 1.11% to 0.1%, reduce the content of monomer isoprene from 3609.79ppm to below 350ppm, and reduce the content of dimer from 4744.80ppm to below 340 ppm.

In addition, the devolatilization method provided by the invention has the advantages of simple process, high efficiency, environmental protection, suitability for heat-sensitive, high-viscosity and high-elasticity polymers, and wide application prospect.

To further illustrate the present invention, the following examples are provided for illustration. The supercritical fluid used in the following examples of the invention is supercritical carbon dioxide, the temperature is higher than the critical temperature of 31.26 ℃, and the pressure is higher than the critical pressure of 7.38 MPa; the content is not less than 99.5% from a carbon dioxide storage tank of the equipment and is of industrial grade.