Method for preparing CBC through full hydrogenation of block copolymer SEBS

Abstract

The invention discloses a method for preparing CBC through full hydrogenation of a block copolymer SEBS, and relates to the technical field of high polymer materials. The method comprises the following steps: refining SEBS base rubber and removing impurities to obtain an SEBS rubber solution; adding the SEBS glue solution into a CBC jet hydrogenation kettle, adding an impurity removal agent to remove impurities, and then adding a supported catalyst to carry out hydrogenation reaction to obtain a CBC glue solution; performing flash evaporation on the CBC glue solution to recover the solvent; carrying out solid-liquid separation on the CBC glue solution and the supported catalyst; preliminarily concentrating the CBC glue solution through a scraper evaporator; carrying out flash evaporation and concentration on the CBC glue solution; the CBC glue solution enters a double-screw devolatilization machine, and a degassing agent is added for solvent removal; and extruding, pelletizing, centrifuging and drying the CBC glue solution to obtain the CBC. After the SEBS base rubber is subjected to refining and impurity removal treatment, the hydrogenation efficiency of a benzene ring of polystyrene in the hydrogenation reaction process is improved, and the gel content of the product is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a method for preparing CBC by the full hydrogenation of a block copolymer SEBS. Background Art

[0002] In the existing industrial production technology of cyclic block copolymers (CBC), the aromatic rings of the block polystyrene and the carbon-carbon double bonds of the polybutadiene in the polystyrene-butadiene-styrene copolymer (SBS) are simultaneously fully hydrogenated to directly produce CBC products. Moreover, the hydrogenation reaction in the hydrogenation kettle is usually carried out by a full-mixing stirrer or a rotating foam stirrer reactor (RFSR) for the hydrogenation reaction of the CBC glue solution.

[0003] However, there are the following defects in the current CBC hydrogenation process: (1) The basic rubber used is the polystyrene-butadiene-styrene copolymer (SBS), and the hydrogenation time usually requires 6 - 8 hours. Moreover, since the high-efficiency catalyst needs to hydrogenate the C = C double bonds in the polybutadiene block, the amount of hydrogenation catalyst used is relatively large. (2) The mixing effect of the glue solution and hydrogen in the CBC hydrogenation kettle during the hydrogenation reaction is average, and the hydrogenation reaction rate is slow, which directly affects the industrial production efficiency. (3) In the existing industrial CBC post-treatment technology for removing residual VOCs, the residual VOCs in the product are relatively high, which will cause environmental pollution during the post-processing of the product and increase the material consumption in production.

[0004] Therefore, it is of great research significance to develop a new CBC production process. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing CBC by the full hydrogenation of a block copolymer SEBS. After the polystyrene-ethylene-butene-styrene copolymer (SEBS) basic rubber is treated by a refining and impurity-removing method in the present invention, the hydrogenation efficiency of the polystyrene benzene ring during the hydrogenation reaction is improved, and the gel content of the product is reduced.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for preparing CBC by the full hydrogenation of a block copolymer SEBS, comprising the following steps:

[0008] (1) Add SEBS into the SEBS sol kettle containing a solvent, introduce an inert gas and carry out refining and impurity-removing to obtain a SEBS glue solution;

[0009] (2) Feed the impurity-removed SEBS glue solution into the CBC basic rubber buffer tank for storage;

[0010] (3) Add the SEBS glue solution to the CBC jet hydrogenation reactor, then add a purification agent for impurity removal, and then add a supported catalyst for hydrogenation reaction to obtain the CBC glue solution;

[0011] (4) The CBC glue solution is discharged into the CBC flash buffer tank for flash evaporation to recover the solvent;

[0012] (5) Transport the CBC glue solution to the CBC glue blending tank, then transport the CBC glue solution to the inlet buffer tank of the centrifuge, and then transport it to the CBC glue centrifuge for solid-liquid separation of the glue solution and the supported catalyst. The supported catalyst is separated and collected into the catalyst separation and collection mobile tank, and the CBC glue solution is separated and transported to the outlet buffer tank of the centrifuge;

[0013] (6) After the CBC glue solution is pumped out from the outlet buffer tank of the centrifuge, an antioxidant is added, and it is mixed evenly through a static mixer, and then heated through a preheater and transported to a wiped film evaporator;

[0014] (7) The CBC glue solution is preliminarily concentrated by the wiped film evaporator. The wiped film evaporator is heated by high-temperature heat transfer oil, and the temperature is controlled by the ratio of the recovered solvent to the solvent of the feed glue solution. The solvent is recovered at the top of the wiped film evaporator and recycled to the solvent refining system;

[0015] (8) The CBC glue solution is transported to a heater after being preliminarily concentrated by the wiped film evaporator, and after heating, it enters the flashing and concentrating tank for feed of the devolatilizer for flashing and concentration;

[0016] (9) After the CBC glue solution comes out from the flashing and concentrating tank for feed of the devolatilizer, it is heated by a heater and then enters a twin-screw devolatilizer. A degassing agent is added in the twin-screw mixing section of the devolatilizer to remove the solvent. The solvent collected at the devolatilization port is recycled to the solvent refining system;

[0017] (10) The CBC product is obtained after the CBC glue solution is extruded, pelletized, centrifuged, and dried by the twin-screw devolatilizer.

[0018] Preferably, in the step (1), the concentration of the SEBS glue solution is 5-8%.

[0019] If the sol concentration of the SEBS glue solution is too high, the solubility of SEBS is poor, and the catalyst cannot react fully; if the sol concentration of the SEBS glue solution is too low, the production capacity decreases. Therefore, by controlling the concentration of the SEBS glue solution, it is beneficial to improve the hydrogenation efficiency.

[0020] Preferably, when an inert gas is introduced in the step (1), the temperature of the SEBS sol kettle is controlled at 55-65 °C, and the operation time is 25-30 min, so that the oxygen content of the glue solution in the system ≤ 2 ppm.

[0021] Preferably, when refining and removing impurities from the SEBS rubber solution in step (1), the temperature of the SEBS sol kettle is controlled at 85 - 95 °C, the operation time is 1 - 3 h, so that the water content in the rubber solution ≤ 50 ppm.

[0022] Preferably, in step (1), the total dissolution time of the SEBS sol kettle is controlled at 8 - 12 h.

[0023] Preferably, in step (2), the temperature in the CBC base rubber buffer tank is controlled at 85 - 95 °C, the liquid level is controlled at 2 - 80%, and the pressure is controlled at 0.1 - 0.3 MPa.

[0024] Preferably, in step (3), the feed temperature of the CBC jet - flow hydrogenation kettle is controlled at 150 - 165 °C, and the pressure before feeding is controlled at 0.5 - 0.8 MPa.

[0025] Preferably, in step (3), the hydrogenation reaction temperature of the CBC jet - flow hydrogenation kettle is controlled at 168 - 175 °C, the hydrogenation reaction pressure is maintained at 6.8 - 7.2 MPa, and the total completion time of the hydrogenation reaction is controlled at 3.5 - 4.5 h.

[0026] Preferably, in step (4), the temperature in the CBC flash buffer tank is controlled at 80 - 90 °C, the liquid level is controlled at 3.1 - 78%, and the pressure is controlled at 0.05 - 0.2 MPa.

[0027] Preferably, in step (5), the temperature of the centrifuge inlet buffer tank is controlled at 75 - 80 °C, the liquid level is controlled at 68.5 - 75%, and the pressure is controlled at 0.05 - 0.13 MPa.

[0028] Preferably, in step (5), the temperature at the inlet of the CBC rubber solution centrifuge is controlled at 75 - 80 °C, the pressure is controlled at 0.1 - 0.18 MPa, and the back pressure at the centrifuge outlet is controlled at 0.25 - 0.3 MPa;

[0029] Preferably, in step (5), the temperature of the centrifuge outlet buffer tank is controlled at 75 - 80 °C, the pressure is controlled at 0.1 - 0.3 MPa, and the liquid level is controlled at 5 - 80%.

[0030] Preferably, in step (6), the temperature of the pre - heater is controlled at 135 - 150 °C.

[0031] Preferably, in step (7), the heat - transfer oil temperature of the scraper evaporator is controlled at 150 - 170 °C, the temperature of the scraper evaporator is controlled at 110 - 135 °C, the pressure is controlled at - 30~ - 50 KPa, and the liquid level is controlled at 30 - 60%.

[0032] Preferably, in the step (8), the pressure of the degassing machine feed flash tank is controlled at 0.0001 - 0.2 MPa, and the temperature is controlled at 85 - 95 °C.

[0033] Preferably, in the step (9), the twin-screw degassing machine is provided with a total of four degassing ports. The pressure of each degassing port is controlled at -30 to -80 KPa, the temperature of each section of the degassing machine is controlled at 160 - 200 °C, the temperature system of the heat transfer oil heating is controlled at 180 - 220 °C, the negative pressure vacuum system is controlled at -30 to -80 KPa, and the pressure of the end template control is controlled at 3.5 - 4.5 MPa.

[0034] Preferably, the raw materials for preparing CBC include the following components in parts by mass:

[0035] 100 parts of SEBS; 560 - 3200 parts of solvent; 0.12 - 0.59 parts of impurity remover; 0.26 - 0.41 parts of supported catalyst; 0.2 - 0.4 parts of antioxidant; 2.2 - 5.1 parts of degassing agent.

[0036] More preferably, the raw materials for preparing CBC include the following components in parts by mass:

[0037] 100 parts of SEBS; 1150 - 1900 parts of solvent; 0.23 - 0.36 parts of impurity remover; 0.28 - 0.38 parts of supported catalyst; 0.27 - 0.35 parts of antioxidant; 2.6 - 4.2 parts of degassing agent.

[0038] Preferably, in the step (1), the average molecular weight distribution of the SEBS is 50,000 - 250,000, the molecular weight distribution is 11,000 - 15,000, the melt index is 0 - 50 g / 10 min, the control index of volatile matter is ≤1%, and the styrene content is 25 - 45%.

[0039] More preferably, the average molecular weight distribution of the SEBS is 60,000 - 200,000, the molecular weight distribution is 11,000 - 14,500, the melt index is 0.1 - 45 g / 10 min, the control index of volatile matter is ≤0.8%, and the styrene content is 25 - 40%.

[0040] Further preferably, the average molecular weight distribution of the SEBS is 70,000 - 150,000, the molecular weight distribution is 11,000 - 13,500, the melt index is 0.1 - 35 g / 10 min, the control index of volatile matter is ≤0.5%, and the styrene content is 25 - 40%.

[0041] Preferably, the EB hydrogenation degree in the SEBS is ≥75%, the content of polyethylene-butene is 55 - 75%, and the content of butene accounts for 35 - 45% of the polyethylene-butene.

[0042] More preferably, in the SEBS, the hydrogenation degree of EB ≥ 90%, the content of polyethylene-butene is 60 - 75%, and the content of butene accounts for 35 - 45% of polyethylene-butene.

[0043] Even more preferably, in the SEBS, the hydrogenation degree of EB ≥ 98%, the content of polyethylene-butene is 60 - 75%, and the content of butene accounts for 35 - 45% of polyethylene-butene.

[0044] Preferably, the particle size of the SEBS is 0.5 - 1.2 mm, and the antioxidant content ≤ 0.6%.

[0045] More preferably, the particle size of the SEBS is 0.5 - 1.0 mm, and the antioxidant content ≤ 0.2%.

[0046] Even more preferably, the particle size of the SEBS is 0.5 - 0.8 mm, and the antioxidant content is 0.

[0047] Preferably, in the step (1), the solvent includes at least one of cyclohexane, cyclopentane, isobutane, n-pentane, isopentane, n-hexane, methylcyclopentane, and n-heptane.

[0048] More preferably, the solvent includes at least one of cyclohexane, cyclopentane, n-hexane, and methylcyclopentane. Even more preferably, it is cyclohexane.

[0049] Preferably, in the step (3), the impurity remover includes at least one of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, and dichloroethylaluminum. By adding the impurity remover in the present invention, residual impurities such as residual water and carbon monoxide can be removed, improving the product quality.

[0050] More preferably, the impurity remover includes at least one of triethylaluminum, triisobutylaluminum, and trioctylaluminum. Even more preferably, it is triisobutylaluminum.

[0051] Preferably, in the step (3), the supported catalyst includes at least one of rhodium-supported catalyst, palladium-supported catalyst, platinum-supported catalyst, nickel / cobalt-supported bimetallic catalyst, rhodium / cobalt-supported bimetallic catalyst, palladium / molybdenum-supported bimetallic catalyst, homogeneous nickel / aluminum catalyst, and metallocene catalyst.

[0052] More preferably, the supported catalyst includes at least one of rhodium-supported catalyst, palladium-supported catalyst, platinum-supported catalyst, nickel / cobalt-supported bimetallic catalyst, rhodium / cobalt-supported bimetallic catalyst, and palladium / molybdenum-supported bimetallic catalyst. Even more preferably, it is palladium / molybdenum-supported bimetallic catalyst.

[0053] Preferably, the support of the palladium / molybdenum supported bimetallic catalyst is SiO2, and the palladium / molybdenum supported bimetallic catalyst is loaded with active components. The mass content of the rhodium-cobalt bimetal in the active components is 3-4 wt% of the mass content of the support, preferably 3.5 wt%.

[0054] Preferably, in the step (6), the antioxidant includes at least one of antioxidant 168, antioxidant 1076, antioxidant 1010, antioxidant 1520, antioxidant 3114, antioxidant TNPP, antioxidant 1080, and antioxidant 4500.

[0055] More preferably, the antioxidant includes at least one of antioxidant 1520, antioxidant 168, antioxidant 1076, antioxidant 1010, and antioxidant 4500.

[0056] Further preferably, it is antioxidant 1520 and antioxidant 1076, and the mass ratio of the two is (1-3):8, preferably 3:8.

[0057] Preferably, in the step (9), the degassing agent includes at least one of supercritical carbon dioxide, demineralized water, and supercritical nitrogen.

[0058] More preferably, the degassing agent includes at least one of supercritical carbon dioxide and demineralized water. Further preferably, it is demineralized water.

[0059] It should be noted that the sources of the SEBS described in the present invention include, but are not limited to, Kraton SEBS grade G1652H, Baling SEBS grade YH-501, and Lee Chang Yung SEBS grade 9550.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] (1) The present invention adopts a brand-new CBC production process technology, which can fully hydrogenate the aromatic rings of the polystyrene-ethylene-butene-styrene copolymer (SEBS) base rubber produced by metallocene titanium, metallocene zirconium, aluminum nickel, aluminum cobalt, and catalyst through a hydrogenation reactor to directly produce CBC polyvinylcyclohexane-ethylene-butene-vinylcyclohexane products. Since the present invention does not require hydrogenation of the C=C double bonds in the polybutadiene block, the amount of hydrogenation catalyst used is significantly reduced. After treating the polystyrene-ethylene-butene-styrene copolymer (SEBS) base rubber by a method of refining and removing impurities, the hydrogenation efficiency of the polystyrene benzene ring in the hydrogenation reaction process is improved, and the gel content of the product is reduced.

[0062] (2) The jet-flow hydrogenation kettle adopted in the present invention is used for stirring, which can shorten the hydrogenation reaction time of the CBC glue solution. The hydrogenation time is shortened from the original reaction time of 5.0 - 6.2 h of the fully mixed stirring hydrogenation kettle to the existing 3.0 - 4.0 h, and various parameters are superior to those of the original fully mixed stirring hydrogenation kettle.

[0063] (3) The present invention newly adds an appropriate amount of degassing agent before the devolatilizer to assist in solvent removal, which can form a low-boiling solvent-water azeotrope. After adding the degassing agent, the VOCs content of the final CBC product can be reduced to ≤100 ppm, reaching the level of international advanced medical and polymer materials. Description of the Drawings

[0064] Figure 1 It is a process schematic diagram for the full hydrogenation of the block copolymer SEBS to prepare CBC according to the present invention. Among them, 1 is the SEBS powder screw feeder; 2 is the SEBS sol kettle; 3 is the high-speed dissolution mixer; 4 is the sol kettle glue solution pump; 5 is the CBC base glue buffer tank; 6 is the hydrogenation kettle glue solution feeding pump; 7 is the CBC jet-flow hydrogenation kettle; 8 is the impurity removal agent feeding tank; 9 is the filling port; 10 is the hydrogenation kettle discharge glue pump; 11 is the CBC flash buffer tank; 12 is the flash recovery tank; 13 is the flash tank discharge glue pump; 14 is the CBC glue solution blending tank; 15 is the glue solution blending tank discharge glue pump; 16 is the centrifuge inlet buffer tank; 17 is the CBC glue solution centrifuge; 18 is the catalyst separation and collection mobile tank; 19 is the centrifuge outlet buffer tank; 20 is the centrifuge outlet buffer tank discharge glue pump; 21 is the antioxidant A storage tank; 22 is the antioxidant B storage tank; 23 is the static mixer; 24 is the preheater; 25 is the scraper evaporator; 26 is the solvent recovery buffer tank; 27 is the solvent recovery pump; 28 is the scraper evaporator discharge glue pump; 29 is the heater A; 30 is the devolatilizer feed flash tank; 31 is the heater B; 32 is the twin-screw devolatilizer; 33 is the heat transfer oil heating temperature system; 34 is the degassing agent buffer tank; 35 is the degassing agent feeding pump; 36 is the underwater pelletizing buffer tank; 37 is the centrifugal dryer; 38 is the CBC packaging system. Detailed Embodiments

[0065] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the protection scope and implementation manner of the present invention are not limited thereto.

[0066] The materials, reagents, etc. used in the following embodiments are, unless otherwise specified, reagents and materials that can be obtained from commercial channels.

[0067] A method for the full hydrogenation of a block copolymer SEBS to prepare CBC includes the following steps:

[0068] (1) The polystyrene-ethylene-butene-styrene copolymer (SEBS) is conveyed through the SEBS powder screw feeder 1 and added into the SEBS sol kettle 2 containing cyclohexane solvent. The high-speed dissolution mixer 3 and the sol kettle glue liquid pump 4 are started for sol operation. After mixing evenly, SEBS glue liquid is obtained, and the concentration of the SEBS glue liquid is 5-8%. The SEBS used is Kraton SEBS from the United States, with the grade of G1652H.

[0069] 1) The temperature of the SEBS sol kettle is controlled at 55-65 °C. Nitrogen is introduced into the SEBS sol kettle to expel impurities such as oxygen and carbon dioxide in the kettle. The operation time is 30 min, so that the oxygen content in the glue liquid in the system ≤ 2 ppm;

[0070] 2) The temperature of the SEBS sol kettle is controlled at 85-95 °C. The SEBS base rubber is refined to remove impurities, so that the water content in the glue liquid ≤ 50 ppm. The operation time is 1-3 h;

[0071] 3) The total dissolution time of the SEBS sol kettle is controlled at 8-12 h.

[0072] (2) The SEBS glue liquid after impurity removal in the SEBS sol kettle is sent to the CBC base rubber buffer tank 5 for storage, in cooperation with the preparation of materials. The storage temperature is controlled at 85-95 °C, the liquid level is controlled at 2-80%, and the pressure is controlled at 0.1-0.3 MPa.

[0073] (3) The SEBS glue liquid in the CBC base rubber buffer tank 5 enters the CBC jet hydrogenation kettle 7 through the hydrogenation kettle glue liquid inlet pump 6. The impurity remover in the impurity remover feeding tank 8 is transported to the CBC jet hydrogenation kettle 7 through the feeding pump, and the supported catalyst enters the CBC jet hydrogenation kettle 7 from the filling port 9. Then, the hydrogenation reaction is carried out in the CBC jet hydrogenation kettle 7 by metering method to obtain the CBC glue liquid. The specific feeding method is shown in Table 1:

[0074] Table 1

[0075]

[0076]

[0077] The influence of the refinement and impurity removal of the SEBS base rubber in the present invention on the production of hydrogenated CBC polymer is shown in Table 2:

[0078] Table 2

[0079]

[0080]

[0081] Table 2 was obtained by testing under the condition that the reaction conditions such as the addition amount of the supported catalyst, the hydrogenation reaction time, the hydrogenation reaction temperature, and the hydrogenation reaction pressure are basically the same. The following conclusions can be drawn from Table 2:

[0082] ① For the CBC product hydrogenated after the refining and impurity removal process in the SEBE sol kettle using the base rubber with 0% SEBS antioxidant content (no antioxidant in SEBE), under the condition that the reaction conditions are basically the same, the hydrogenation efficiency of the polystyrene benzene ring can reach the control index of ≥98%, the gel content in the glue solution is normal, and this process can stabilize the quality of the CBC product.

[0083] ② For the CBC product hydrogenated without the refining and impurity removal process in the SEBE sol kettle using the base rubber with 0% SEBS antioxidant content (no antioxidant in SEBE), under the condition that the reaction conditions are basically the same, the hydrogenation efficiency of the polystyrene benzene ring of the CBC product is poor, and at the same time, the gel content in the glue solution increases significantly, affecting the product quality.

[0084] ③ For the CBC product hydrogenated after the refining and impurity removal process in the SEBE sol kettle using the base rubber with 0.4% SEBS antioxidant content, under the condition that the reaction conditions are basically the same, the hydrogenation efficiency of the polystyrene benzene ring of the CBC product shows a downward trend and cannot reach the control index of ≥98% for the hydrogenation efficiency of the polystyrene benzene ring.

[0085] The influence of the CBC jet flow hydrogenation kettle 7 of the present invention on the preparation of the hydrogenated CBC glue solution is shown in Table 3 as follows:

[0086] Table 3

[0087]

[0088]

[0089] Table 3 was obtained by testing under the condition that the reaction conditions such as the addition amount of the supported catalyst, the hydrogenation reaction time, the hydrogenation reaction temperature, and the hydrogenation reaction pressure are basically the same. It can be seen from Table 3 that the CBC jet flow hydrogenation kettle adopted by the present invention can shorten the hydrogenation reaction time and significantly improve the production efficiency of the CBC product under the condition that other reaction conditions are basically the same.

[0090] (4) The CBC glue solution is sent into the CBC flash buffer tank 11 by the glue outlet pump 10 of the hydrogenation kettle for flash evaporation to recover the solvent. The temperature in the CBC flash buffer tank 11 is controlled at 80 - 90 °C, the liquid level is controlled at 3.1 - 78%, and the pressure is controlled at 0.05 - 0.2 MPa; part of the solvent is recovered into the flash recovery tank 12 after flash evaporation and then sent to the solvent refining and separation unit for recycling.

[0091] (5) The CBC glue solution in the CBC flash evaporation buffer tank 11 is transported to the CBC glue solution blending tank 14 by the glue solution pump 13 of the flash evaporation tank to evenly distribute the glue solution, making the product quality more stable; the CBC glue solution is transported to the centrifuge inlet buffer tank 16 by the glue solution pump 15 of the blending tank, with the temperature controlled at 75 - 80 °C, the liquid level controlled at 68.5 - 75%, and the pressure controlled at 0.05 - 0.13 MPa; the centrifuge inlet buffer tank 16 enters the subsequent CBC glue solution centrifuge 17 by means of overflow.

[0092] (6) The CBC glue solution centrifuge 17 separates the solid and liquid of the glue solution and the supported catalyst. The supported catalyst (palladium / molybdenum supported bimetallic catalyst) is collected by the centrifuge slag phase separation into the catalyst separation and collection mobile tank 18. After intermittent collection, it is recycled to the catalyst manufacturer for regeneration and then supplied for device circulation use. The CBC glue solution is transported to the centrifuge outlet buffer tank 19 by the centrifuge light phase separation. The inlet temperature of the CBC glue solution centrifuge 17 is controlled at 75 - 80 °C, the pressure is controlled at 0.1 - 0.18 MPa, and the outlet back pressure of the CBC glue solution centrifuge 17 is controlled at 0.25 - 0.3 MPa. The temperature control index of the centrifuge outlet buffer tank 19 is 75 - 80 °C, the pressure control index is 0.1 - 0.3 MPa, and the liquid level is controlled at 5 - 80%.

[0093] (7) After the CBC glue solution comes out of the glue solution pump 20 of the centrifuge outlet buffer tank, antioxidant A (antioxidant 1520) is added to the antioxidant A storage tank 21, and antioxidant B (antioxidant 1076) is added to the antioxidant B storage tank 22. The mass ratio of antioxidant A to antioxidant B is 3:8. Antioxidant A and antioxidant B are mixed evenly by the static mixer 23, and then heated to 135 - 150 °C by the subsequent preheater 24 and transported to the scraper evaporator 25.

[0094] (8) When the glue solution passes through the scraper evaporator 25, it is forced into a CBC glue film by the rotating scraper to increase the evaporation area of the glue solution. The scraper evaporator is heated by high-temperature heat-conducting oil, and the temperature is regulated by the ratio of the extracted solvent to the solvent of the feed glue solution, so as to control the glue solution to be concentrated to 28 - 33% after passing through the scraper evaporator. The solvent is extracted from the top of the scraper evaporator 25 to the solvent recovery buffer tank 26, and finally recycled to the solvent refining system for circulation use by the solvent recovery pump 27. The heat-conducting oil temperature of the scraper evaporator is controlled at 150 - 170 °C, the temperature of the scraper evaporator is 110 - 135 °C, the pressure is -30~-50 KPa, and the liquid level is controlled at 30 - 60%.

[0095] (9) After the glue solution is preliminarily concentrated by the scraper evaporator 25, it is transported to the heater A 29 by the glue discharge pump 28 of the scraper evaporator. After the temperature is raised to 120 - 145 °C, it enters the flash evaporation tank 30 for feeding the devolatilizer. The pressure of the flash evaporation tank 30 for feeding the devolatilizer is controlled at 0.0001 - 0.2 MPa, and the temperature is controlled at 85 - 95 °C. After the glue solution is concentrated to 38 - 48% by flash evaporation, it is sent to the twin-screw devolatilizer 32 below through the heater B 31.

[0096] (10) After the glue solution comes out of the flash evaporation tank 30 for feeding the devolatilizer, it is heated to 138 - 150 °C by the heater 31 and then enters the twin-screw devolatilizer 32. The twin-screw devolatilizer 32 is provided with a total of four devolatilization ports. The pressure of each section of the devolatilization port is controlled at -30 to -80 KPa. The temperature of each section of the devolatilizer is controlled at 160 - 200 °C. The temperature system of the heat transfer oil heating is controlled at 180 - 220 °C, and the negative pressure vacuum system is controlled at -30 to -80 KPa. The pressure of the end template control is controlled at 3.5 - 4.5 MPa. The glue solution is driven by the rotation and extrusion of the twin-screws to continuously advance. At the same time, the solvent is removed by vacuum pumping at the devolatilization ports respectively. The solvent collected at the devolatilization ports is recycled to the solvent refining system for reuse.

[0097] In the present invention, an appropriate amount of degassing agent (88 - 92 °C) is added to the twin-screw mixing section in front of the 1# port (A) of the devolatilizer to assist in solvent removal, and a cyclohexane solvent - water azeotrope with a low boiling point can be formed. The degassing agent in the degassing agent buffer tank 34 is transported to the twin-screw devolatilizer 32 by the degassing agent feeding pump 35. After adding the degassing agent (desalted water), the glue solution enters the underwater pelletizing buffer tank 36, and after underwater pelletizing, it is sent into the centrifugal dryer 37. The VOCs content of the CBC product can be reduced to ≤100 ppm.

[0098] The influence of different amounts of degassing agent added on the VOCs of the CBC product is shown in Table 4:

[0099] Table 4

[0100]

[0101] It can be seen from Table 4 that when 2.6 - 4.2 parts of degassing agent are added under the same conditions of the glue solution concentration entering the devolatilizer and the temperature of the mixing section of the devolatilizer, it helps to reduce the VOCs content of the CBC product.

[0102] (11) After being extruded, pelletized, and centrifugally dried by the twin-screw devolatilizer 32, the glue solution is sent by air to the CBC packaging system 38 for packaging and warehousing.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing CBC by fully hydrogenating block copolymer SEBS, characterized in that, It includes the following steps: (1) Add SEBS into the SEBS sol kettle containing solvent, introduce inert gas and carry out refining and impurity removal to obtain SEBS glue liquid; (2) Feed the impurity-removed SEBS glue liquid into the CBC base rubber buffer tank for storage; (3) Add the SEBS glue liquid to the CBC jet flow hydrogenation kettle, then add a deimpurifying agent for impurity removal, and then add a supported catalyst for hydrogenation reaction to obtain CBC glue liquid; (4) The CBC glue liquid is discharged into the CBC flash buffer tank for flash evaporation to recover the solvent; (5) Transport the CBC glue liquid to the CBC glue liquid blending tank, then transport the CBC glue liquid to the centrifuge inlet buffer tank, and then transport it to the CBC glue liquid centrifuge for solid-liquid separation of the glue liquid and the supported catalyst. The supported catalyst is collected by separation into the catalyst separation and collection mobile tank, and the CBC glue liquid is transported by separation to the centrifuge outlet buffer tank; (6) After the CBC glue liquid is pumped out from the centrifuge outlet buffer tank, add an antioxidant, mix evenly through a static mixer, and then transport it to a scraping evaporator after heating through a preheater; (7) The CBC glue liquid is preliminarily concentrated through a scraping evaporator. The scraping evaporator is heated by high-temperature heat-conducting oil, and the temperature is controlled by the ratio of the recovered solvent to the solvent of the feed glue liquid. The solvent is taken out from the top of the scraping evaporator and recycled to the solvent refining system for reuse; (8) The CBC glue liquid is transported to a heater after being preliminarily concentrated by the scraping evaporator, and enters a devolatilization machine feed flash tank for flash evaporation and concentration after heating; (9) After the CBC glue liquid comes out from the devolatilization machine feed flash tank, it enters a twin-screw devolatilization machine after being heated by a heater, and a degassing agent is added to remove the solvent in the twin-screw mixing section of the devolatilization machine. The solvent collected at the devolatilization port is recycled to the solvent refining system for reuse; (10) The CBC glue liquid is extruded, pelletized, centrifuged, and dried by the twin-screw devolatilization machine to obtain the CBC product.

2. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as described in claim 1, characterized in that, In the step (1), the concentration of the SEBS glue liquid is 5-8%; and / or, When introducing inert gas in the step (1), the temperature of the SEBS sol kettle is controlled at 55-65°C, and the operation time is 25-30 min; and / or, When carrying out refining and impurity removal on the SEBS glue liquid in the step (1), the temperature of the SEBS sol kettle is controlled at 85-95°C, and the operation time is 1-3 h; and / or, In the step (1), the total dissolution time of the SEBS sol kettle is controlled at 8-12 h.

3. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as described in claim 1, characterized in that, In the step (2), the temperature in the CBC base rubber buffer tank is controlled at 85-95°C, the liquid level is controlled at 2-80%, and the pressure is controlled at 0.1-0.3 MPa; and / or, In the step (4), the temperature in the CBC flash buffer tank is controlled at 80-90°C, the liquid level is controlled at 3.1-78%, and the pressure is controlled at 0.05-0.2 MPa.

4. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as claimed in claim 1, characterized in that, In the step (5), the temperature of the centrifuge inlet buffer tank is controlled at 75-80°C, the liquid level is controlled at 68.5-75%, and the pressure is controlled at 0.05-0.13 MPa.

5. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as described in claim 1, characterized in that, In step (7), the heat transfer oil temperature of the scraper evaporator is controlled at 150 - 170°C, the temperature of the scraper evaporator is controlled at 110 - 135°C, the pressure is controlled at -30 to -50 KPa, and the liquid level is controlled at 30 - 60%.

6. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as described in claim 1, characterized in that, In step (8), the pressure of the feed flash tank of the devolatilizer is controlled at 0.0001 - 0.2 MPa, and the temperature is controlled at 85 - 95°C; and / or, In step (9), the twin-screw devolatilizer is provided with a total of four devolatilization ports. The pressure of each devolatilization port is controlled at -30 to -80 KPa, the temperature of each section of the devolatilizer is controlled at 160 - 200°C, the heat transfer oil heating temperature system is controlled at 180 - 220°C, the negative pressure vacuum system is controlled at -30 to -80 KPa, and the pressure of the end template control is controlled at 3.5 - 4.5 MPa.

7. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as described in claim 1, characterized in that, In step (1), the average molecular weight distribution of the SEBS is 50,000 - 250,000, the molecular weight distribution is 11,000 - 15,000, the melt index is 0 - 50 g / 10 min, the control index of volatile matter is ≤1%, and the styrene content is 25 - 45%; in the SEBS, the EB hydrogenation degree ≥75%, the content of polyethylene-butene is 55 - 75%, the content of butene accounts for 35 - 45% of polyethylene-butene, and the particle size of the SEBS is 0.5 - 1.2 mm.

8. The method for preparing CBC by the full hydrogenation of the block copolymer SEBS as described in claim 1, characterized in that, In step (1), the solvent includes at least one of cyclohexane, cyclopentane, isobutane, n-pentane, isopentane, n-hexane, methylcyclopentane, and n-heptane.

9. The method for preparing CBC by fully hydrogenating the block copolymer SEBS as described in claim 1, characterized in that, In step (3), the scavenger includes at least one of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, and dichloroethylaluminum; and / or, The supported catalyst includes at least one of a rhodium-supported catalyst, a palladium-supported catalyst, a platinum-supported catalyst, a nickel / cobalt-supported bimetallic catalyst, a rhodium / cobalt-supported bimetallic catalyst, a palladium / molybdenum-supported bimetallic catalyst, a homogeneous nickel / aluminum catalyst, and a metallocene catalyst.

10. The method for preparing CBC by the full hydrogenation of the block copolymer SEBS according to claim 1, characterized in that, In step (6), the antioxidant includes at least one of antioxidant 168, antioxidant 1076, antioxidant 1010, antioxidant 1520, antioxidant 3114, antioxidant TNPP, antioxidant 1080, and antioxidant 4500; and / or, In step (9), the degassing agent includes at least one of supercritical carbon dioxide, demineralized water, and supercritical nitrogen.

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