Synthesis method of new SSBR product
By adding magnesium salt additives and cyclohexane to the coagulation and recycling system, the problem of glue leakage during high viscosity PBT processing is solved, and cost reduction and product quality improvement are achieved.
Patent Information
- Application Number
- CN202510337643.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2025-06-13
AI Technical Summary
The existing high-viscosity PBT is prone to leakage during processing, resulting in large production costs and losses.
By continuously adding magnesium salt additives to the coagulation and recovery system, the particle size of the product is increased and the cyclohexane is recycled and reused, the design and process flow of the coagulation and recovery system is improved.
It effectively solves the problem of glue leakage, reduces production costs, and improves the quality of the product.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of new material processing, and specifically to a synthesis method of a new SSBR product. Background Art
[0002] In recent years, the solid-phase tackifying technology has been adopted to replace PTT with PBT products having a degree of polymerization of 150-200 and a molecular weight of ≥40,000 for blending with PET, and then weaving into clothing fabrics. However, this method has a relatively high cost.
[0003] Polybutylene terephthalate (PBT) is a milky white semi-transparent to opaque, semi-crystalline thermoplastic polyester, which has high heat resistance and low cost. PBT high-viscosity products with a degree of polymerization of about 100 and a molecular weight of 20,000-35,000 can meet the requirements of textiles and film products. Spinning has excellent elongation elastic recovery rate and is easy to dye, and is widely used in fields such as brush filaments, wig filaments, and pre-oriented filaments for core-spun yarns. Therefore, the high-viscosity PBT produced by the CP one-step method greatly reduces the production cost and is more conducive to market promotion.
[0004] However, the existing high-viscosity PBT is prone to glue leakage during the processing, resulting in a large loss of production cost. Therefore, improvement is needed. Summary of the Invention
[0005] The purpose of the present invention is to provide a synthesis method of a new SSBR product to solve the problem of glue leakage that easily occurs in the existing high-viscosity PBT during the processing, resulting in a large loss of production cost as mentioned in the above background art.
[0006] To achieve the above purpose, the present invention provides the following technical solution: A synthesis method of a new SSBR product, comprising the following steps: S1. Raw material refining: Feeding crude styrene into a group of drying absorption towers to obtain refined styrene; Feeding crude butadiene through a group of rectification towers to obtain refined butadiene; Feeding crude cyclohexane through a rectification tower to obtain refined cyclohexane; S2. Polymerization reaction: Feeding the refined cyclohexane, refined styrene, and refined butadiene prepared in step S1 into a polymerization reactor according to a molar mass ratio of 23.32:1:2.35, and stirring and mixing for 10 minutes; then, under the conditions of an initiation temperature of 53°C and an initiation pressure of 0.3 Mpa, adding an initiator to initiate the polymerization reaction. Under the action of the initiator, styrene and butadiene undergo a rapid polymerization reaction. Then, when the temperature reaches 115-120°C and the pressure reaches 0.45 Mpa, under the reaction conditions of high temperature and high pressure, staying for 1 hour to make the final conversion rate reach more than 99% and the molecular weight reach 130,000-140,000; S3. Coagulation and recovery system: A terminator and an antioxidant are added to the product after the polymerization reaction in step S2, and then it is sent into the blending tank in the blending system. Then, it is pumped from the blending tank into the coagulation and recovery system by a glue spraying pump. Under the action of hot water and stirring, the glue liquid is dispersed into small glue droplets the size of pearls in the coagulation kettle of the coagulation and recovery system. At the same time, a magnesium salt auxiliary agent is continuously added to the coagulation and recovery system at a content of about 100 - 200 ppm in water. The cyclohexane in the small glue droplets is evaporated and recovered into the crude cyclohexane refining system in step S1 for recycling. The solvent-free rubber particles are sent into the next dehydration and drying system by hot water; S4. Dehydration and drying system: The rubber particles first pass through a vibrating screen to remove 50% of the free water, then are buffered in a rubber washing tank, and then enter another vibrating screen for sieving. Then, the rubber particles with a water content of 50% enter an extrusion dehydrator. After the rubber particles are frictionally heated inside the extrusion dehydrator, small particles with a water content of less than 20% are formed. The small particles fall freely into an expansion dryer. The rubber particles are heated and pressurized under the shearing of the shear screws in the barrel of the expansion dryer, and finally flash out from the barrel, controlling the water content to 8 - 12%. Then, it is buffered by a wedge-shaped fluidized bed and then transported to the packaging system; S5. Packaging system: The rubber particles enter an electronic scale for weighing, are pressed into blocks, undergo metal detection and weight detection, are surface-coated with a film and then bagged, and are palletized and stored in the warehouse by a robot.
[0007] Preferably, the water value of the refined styrene prepared in step S1 is less than or equal to 15 ppm; the water value of the refined butadiene is less than or equal to 15 ppm; the water value of the refined cyclohexane is less than or equal to 20 ppm.
[0008] Preferably, three coagulation kettles are provided in step S3, and they are connected in sequence to perform three micro-negative pressure coagulation operations on the transported product. Among them, the temperature of the first coagulation kettle is controlled at 80 - 85 °C, and the pressure is controlled at a micro-negative pressure state of 1 - 10 kPa; the temperature of the second coagulation kettle is controlled at 103 - 108 °C, and the pressure is controlled at a micro-negative pressure state of 30 - 50 kPa; the temperature of the second coagulation kettle is controlled at 103 - 105 °C, and the pressure is controlled at a micro-negative pressure state of 1 - 10 kPa.
[0009] Preferably, in step S3, the temperature of the polymerized product is controlled within 109 °C, and after staying at a high temperature for 5 minutes, a terminator is added for termination.
[0010] Preferably, in step S4, while the rubber particles are being transported forward in the wedge-shaped fluidized bed, the volatile content of the rubber particles is controlled below 0.75%.
[0011] Preferably, in step S4, a Johnson screen structure with gradually decreasing gaps is adopted for the vibrating screen, which reduces the leakage of glue while increasing the dehydration effect of the rubber particles.
[0012] In step S4, the rubber particles are subjected to self-reflux friction inside the expansion dryer cylinder, and the temperature of the rubber particles is ensured to be not lower than 130 °C.
[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: In order to solve the problems of large glue leakage, large loss and easy particle breakage in the coagulation recovery system, a magnesium salt additive is continuously added to the coagulation recovery system at a content of about 100-200 ppm in water, which greatly increases the particle size of the product, solves the problem of glue leakage, and recovers and reuses cyclohexane, further reducing the processing cost. Specific embodiments
[0014] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Example 1
[0015] An embodiment provided by the present invention: A synthesis method of a new SSBR product, comprising the following steps: S1. Raw material refining: Send the crude styrene into a group of drying absorption towers to obtain refined styrene; Send the crude butadiene through a group of rectifying towers to obtain refined butadiene; Send the crude cyclohexane through a rectifying tower to obtain refined cyclohexane; S2. Polymerization reaction: Put the refined cyclohexane, refined styrene, and refined butadiene prepared in step S1 into the polymerization reactor according to a molar mass ratio of 23.32:1:2.35, and stir and mix for 10 minutes; then, under the conditions of an initiation temperature of 53 °C and an initiation pressure of 0.3 Mpa, add an initiator to initiate the polymerization reaction. Under the action of the initiator, styrene and butadiene undergo a rapid polymerization reaction. Then, when the temperature reaches 115-120 °C and the pressure reaches 0.45 Mpa, under the reaction conditions of high temperature and high pressure, stay for 1 hour to make the final conversion rate reach more than 99% and the molecular weight reach 130,000-140,000; S3. Coagulation and Recovery System: A terminator and an antioxidant are added to the product after the polymerization reaction in step S2, and then it is sent into the blending tank in the blending system. Then, it is pumped into the coagulation and recovery system from the blending tank by a glue spraying pump. Under the action of hot water and stirring, the glue liquid is dispersed into small glue droplets the size of pearls in the coagulation kettle of the coagulation and recovery system. In step S3, there are three coagulation kettles in total, which are connected in sequence to perform three times of micro-negative pressure coagulation operations on the transported product. The temperature of the first coagulation kettle is controlled at 80 - 85 °C, and the pressure is controlled at a micro-negative pressure state of 1 - 10 kPa; the temperature of the second coagulation kettle is controlled at 103 - 108 °C, and the pressure is controlled at a micro-negative pressure state of 30 - 50 kPa; the temperature of the second coagulation kettle is controlled at 103 - 105 °C, and the pressure is controlled at a micro-negative pressure state of 1 - 10 kPa; meanwhile, a magnesium salt additive is continuously added to the coagulation and recovery system at a content of about 100 - 200 ppm in water; the cyclohexane in the small glue droplets is evaporated and recovered into the crude cyclohexane refining system in step S1 for recycling, and the solvent-free rubber particles are sent into the next dehydration and drying system by hot water; S4. Dehydration and Drying System: The rubber particles first pass through a vibrating screen to remove 50% of the free water, then are buffered in a rubber washing tank, and then enter another vibrating screen for sieving. Then, the rubber particles with a water content of 50% enter an extrusion dehydrator. After the rubber particles are friction-heated inside the extrusion dehydrator, small particles with a water content of less than 20% are formed. The small particles fall freely into an expansion dryer. Inside the barrel of the expansion dryer, the rubber particles are pressurized by shearing under the shearing of the shear screws, and finally flash out from the barrel. According to the unique properties of the rubber particles, the present invention reduces the opening rate of the extrusion machine, and adopts the principle of simultaneous extrusion and flash evaporation to ensure the water value at the outlet of the extrusion machine while making the outlet rubber particles in a granular state; the water content is controlled at 8 - 12%; then it is buffered by a wedge-shaped fluidized bed. While the rubber particles are being transported forward in the wedge-shaped fluidized bed, the volatile content of the rubber particles is controlled at less than 0.75%, and then it is transported to the packaging system; in step S4, the rubber particles adopt self-reflux friction inside the barrel of the expansion dryer, and the temperature of the rubber particles is ensured to be not lower than 130 °C; S5. Packaging System: The rubber particles enter an electronic scale for weighing, are pressed into blocks, undergo metal detection and weight detection, are surface-coated with a film, and then are bagged and robotically palletized and stored in the warehouse.
[0016] Preferably, the water value of the refined styrene prepared in step S1 is less than or equal to 15 ppm; the water value of the refined butadiene is less than or equal to 15 ppm; the water value of the refined cyclohexane is less than or equal to 20 ppm.
[0017] Preferably, in step S3, the high temperature of the polymerized product is controlled within 109 °C, and after staying at a high temperature for 5 minutes, a terminator is added for termination.
[0018] Preferably, in order to increase the dehydration effect of the rubber particles, in step S4, the vibrating screen adopts a Johnson mesh structure with gradually decreasing gaps, which reduces the leakage of rubber while increasing the dehydration effect of the rubber particles.
[0019] At the same time, the index data of the product prepared by the present invention were tested, and the specific data are as follows: styrene content 28-32%; block styrene content 20-26%; gel content <0.04%; viscosity of 5% styrene solution 21-29; Mooney viscosity <140.
[0020] Moreover, in order to solve the problems of large rubber leakage, large loss and easy particle breakage in the coagulation recovery system, a magnesium salt additive is continuously added to the coagulation recovery system at a content of about 100-200 ppm in water. Since the magnesium salt has losses, the magnesium salt needs to be continuously replenished. The standard operation method is to ensure that the magnesium salt content in water is 100-200 ppm. When the magnesium salt content is insufficient, magnesium salt is added, which greatly increases the particle size of the product, solves the problem of rubber leakage, and recovers and reuses cyclohexane, further reducing the processing cost.
[0021] All the equipment involved in this embodiment belongs to the conventional technology in the field, so no detailed description will be given here.
[0022] And through experiments, it is proved that before adding magnesium salt, 8 bags of broken rubber leaked per hour, and after adding magnesium salt, it generally dropped to 2 bags / hour. Therefore, adding magnesium salt to this processing equipment can reduce rubber leakage.
[0023] At the same time, a new product prepared by the present invention, defined by the company as CH132, was tested. Finally, the following test table was obtained. It can be clearly found from the following table that the overall volatile matter, gel content and viscosity of the new product prepared by the present invention meet the requirements, and the product data meet the superior grade products in the same industry.
Claims
1. A method for synthesizing a new SSBR product, characterized in that: The steps include: S1. Raw material refining: The crude styrene is sent into a set of drying and absorption towers to prepare refined styrene; The crude butadiene is passed through a set of distillation towers to obtain refined butadiene; The crude cyclohexane is distilled in a rectification tower to obtain refined cyclohexane; S2, polymerization reaction: the refined cyclohexane, refined styrene and refined butadiene prepared in step S1 are put into a polymerization reaction kettle at a molar mass ratio of 23.32:1:2.35, and stirred for 10 minutes; then, under the conditions of an initiation temperature of 53°C and an initiation pressure of 0.3Mpa, an initiator is added to initiate the polymerization reaction, under the action of the initiator, styrene and butadiene undergo a rapid polymerization reaction, and then when the temperature reaches 115-120°C and the pressure reaches 0.45Mpa, the reaction is kept for 1 hour under high temperature and high pressure conditions, so that the final conversion rate reaches more than 99% and the molecular weight reaches 130000-140000; S3, condensation recovery system: adding terminator and antioxidant to the product after the polymerization reaction in step S2, and then sending it to the blending tank in the blending system, and then pumping it from the blending tank to the condensation recovery system through the glue spraying pump, and continuously adding magnesium salt auxiliary agent in the condensation recovery system; the colloid particles after the solvent is removed are sent to the next step of dehydration and drying system by hot water; S4, dehydration and drying system: The rubber particles first pass through a vibrating screen to remove 50% of the free water, and then enter another vibrating screen for screening after being buffered in the rubber washing tank. Then the rubber particles with a water content of 50% enter the extrusion dehydrator. After the rubber particles are heated by friction inside the extrusion dehydrator, they form small particles with a water content of less than 20%. The small particles freely fall into the expansion dryer. The rubber particles are heated and pressurized in the cylinder of the expansion dryer under the shearing of the shear screw, and finally flash out from the cylinder to control the moisture content at 8-12%; then they are buffered by the wedge-shaped fluidized bed and transported to the packaging system; S5. Packaging system: After the granules are weighed on the electronic scale, they are pressed into blocks, and then go through metal detection and weight detection. After the surface is coated, they are bagged and then stacked by robots for storage.
2. The method for synthesizing a new SSBR product according to claim 1, characterized in that: The water content of the refined styrene prepared in step S1 is less than or equal to 15 ppm; the water content of the refined butadiene is less than or equal to 15 ppm; and the water content of the refined cyclohexane is less than or equal to 20 ppm.
3. The synthetic method of a new SSBR product according to claim 1, characterized in that: In step S3, there are three condensation kettles in total, which are connected in sequence to realize three micro-negative pressure condensation operations on the transported product, wherein the temperature of the first condensation kettle is controlled at 80-85°C, and the pressure is controlled at a micro-negative pressure state of 1-10kpa; the temperature of the second condensation kettle is controlled at 103-108°C, and the pressure is controlled at a micro-negative pressure state of 30-50kpa; the temperature of the third condensation kettle is controlled at 103-105°C, and the pressure is controlled at a micro-negative pressure state of 1-10kpa.
4. The method for synthesizing a new SSBR product according to claim 1, characterized in that: In step S3 The high temperature of the polymerized product was controlled within 109°C, and after staying at high temperature for 5 minutes, a terminator was added to terminate the polymerization.
5. The method for synthesizing a new SSBR product according to claim 1, characterized in that: In step S4, while the rubber particles are transported forward in the wedge-shaped fluidized bed, the volatile matter of the rubber particles is controlled to be below 0.75%.
6. The method for synthesizing a new SSBR product according to claim 1, characterized in that: In step S4, the vibrating screen adopts a Johnson mesh structure with gradually decreasing gaps, which reduces glue leakage and increases the dehydration effect of the glue particles.
7. A method for synthesizing a new SSBR product according to claim 1, characterized in that: In step S4, the rubber particles are subjected to self-reflux friction in the cylinder of the expansion dryer, and the temperature of the rubber particles is ensured to be not less than 130°C.