Water-containing ABS (Acrylonitrile Butadiene Styrene) resin powder extruding and blending device and process

Abstract

The invention belongs to the field of ABS (Acrylonitrile Butadiene Styrene) resin production processes, and discloses a water-containing ABS resin powder extruding and blending device and process. The extruder comprises 10 sections of cylinders, a die head and a screw rod in the cylinders which are connected in sequence, and the screw rod is used for conveying and / or shearing materials; the feeding structure comprises 3-5 metering feeding units and a gravity flow conveying pipeline, and each metering feeding unit comprises a weightlessness scale and a discharging pipeline; temperature control units are respectively arranged in each section of the barrel body and the die head and are used for monitoring and adjusting the temperature; a water vapor outlet is formed in the side wall of the fifth section of the cylinder body; and vacuum exhaust ports are respectively formed in the seventh section and the ninth section of the cylinder body. According to the water-containing ABS resin powder extrusion blending process, the technical problems of continuous feeding, water removal, resin blending and the like of water-containing materials are solved, and an efficient, continuous and stable ABS resin wet extrusion process is realized.

Description

Technical Field

[0001] The invention belongs to the field of ABS resin production technology, and in particular relates to a water-containing ABS resin powder extrusion blending device and technology. Background Art

[0002] ABS resin is a two-phase structure in which the rubber phase is dispersed in the SAN resin phase. At present, the main international ABS resin production processes are emulsion grafting-bulk SAN blending process and continuous bulk process. The continuous bulk process dissolves the polymerized rubber in the polymerized monomer, so it basically does not involve the problem of co-extrusion. However, the continuous bulk process has a special equipment structure and a small number of product types, and its application field is limited, so this process has not been widely adopted. The emulsion grafting-bulk SAN blending ABS production process has the characteristics of mature technology, excellent product performance, a wide variety, and easy brand switching. Currently, more than 85% of ABS products are produced by this process.

[0003] The emulsion grafting-bulk SAN blending process includes four parts: rubber synthesis, ABS grafted polymer synthesis, SAN resin synthesis, and mixing, blending and extrusion. Among them, SAN resin is usually synthesized through bulk process, while ABS grafted polymer is first synthesized into polybutadiene rubber particles through emulsion polymerization process, and then styrene and acrylonitrile are grafted on the outer layer of rubber particles to form ABS grafted polymer. ABS grafted polymer and SAN resin are mixed to form ABS resin. In the traditional emulsion grafting-bulk SAN blending process, ABS grafting polymerization and SAN polymerization are independent of each other. After producing ABS grafted polymer dry powder and SAN resin particles, they are blended through an extruder. Each process unit of this process is independent, with great operational flexibility, multiple production grades, and flexible production. It is suitable for the production of special materials, special grades, small batches, and colored products. This process is also called a dry process.

[0004] The traditional ABS graft polymer production process is mainly through air or nitrogen fluidized bed drying process, the process is: the condensed ABS graft polymer slurry is pumped to a vacuum belt filter for cleaning and filtering, the electrolyte, emulsifier and other water-soluble substances added in the reaction process are removed, and the slurry is filtered to form a filter cake with a water content of about 50wt%, the filter cake falls into an extrusion dehydrator or a centrifugal dehydrator by gravity, and is further dehydrated to 10-30wt%, the dehydrated material is crushed into fine powder by a crusher, the fine powder is added to the fluidized bed dryer, the moisture content of the dried powder is less than 1wt%, the dry powder is stored in the silo, and the air delivery pipeline is used to intermittently feed the material according to the operation of the extruder during use. The fluidized bed drying process has high energy consumption and material consumption, serious environmental pollution, and there is a safety hazard of powder combustion and explosion. Domestic and foreign companies have experienced flash explosions of dryers or powder combustion accidents. At the same time, the drying process also causes the powder to age, reducing product performance, especially affecting the whiteness of the final product.

[0005] The best process route to solve the safety hazards of the drying process of ABS grafted polymer is to cancel the fluidized bed drying process. There are three technical difficulties in the wet extrusion of ABS resin. The first is to continuously and stably add the water-containing material to the extruder to prevent water vapor from flowing back along the feeding system, which will cause material bridging. The second is that the water added to the extruder can be fully released and discharged from the extruder through a specific device at a designated position, and the water discharge process cannot bring the material out. The third is that on the basis of completing the addition of water-containing materials and the removal of water from the extruder, the components can still be mixed and dispersed evenly to ensure the product quality of the blend.

[0006] Therefore, it is necessary to provide an extrusion process suitable for blending water-containing ABS wet powder with materials such as SAN resin, to solve the problems of steam bridging, water vapor escape, rubber dispersion, product quality control, etc. caused by water vaporization during the addition of wet powder, and to achieve an efficient, continuous and stable ABS resin wet extrusion process. Summary of the invention

[0007] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide an extrusion process suitable for blending water-containing ABS wet powder with materials such as SAN resin, solve the problems of steam bridging, water vapor escape, rubber dispersion, product quality control, etc. caused by water vaporization during the addition of wet powder, and realize an efficient, continuous and stable ABS resin wet extrusion process.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A water-containing ABS resin powder extrusion and blending device, comprising a feeding structure and an extruder;

[0010] The extruder includes 10 sections of a barrel, a die head and a screw in the barrel, which are connected in sequence. The screw is used to convey and / or shear the material.

[0011] The feeding structure includes 3-5 metering feeding units and gravity flow conveying pipelines.

[0012] The metering and feeding unit includes a loss-in-weight scale and a discharge pipeline, and the discharge pipeline is connected to the cylinder of the first section through the same gravity flow conveying pipeline, and is used for continuous metering and adding ABS wet powder, SAN resin and additives;

[0013] The gravity flow conveying pipeline forms an angle of 10-30 degrees with the horizontal plane. The material on the gravity flow conveying pipeline uses SAN resin as a carrier, and relies on friction and vibration of the gravity flow conveying pipeline to achieve premixing of ABS wet powder and SAN resin;

[0014] Each section of the barrel and the die head is provided with a temperature control unit for monitoring and adjusting the temperature;

[0015] The side wall of the 5th section cylinder is provided with a water vapor outlet, and the 7th and 9th sections cylinder are respectively provided with vacuum exhaust ports.

[0016] Furthermore, the water vapor outlet is connected to a reverse thrust exhaust device, which includes a screw barrel, a reverse thrust screw and a variable frequency speed regulating device. The reverse thrust exhaust device is connected to the water vapor outlet through the screw barrel, the reverse thrust screw is arranged in the screw barrel, one end of the reverse thrust screw is connected to the variable frequency speed regulating device, and the variable frequency speed regulating device is used to drive the reverse thrust screw to rotate axially. The reverse thrust screw is close to the extruder and has a head with a small lead thread of the compression section. The material in the barrel only contacts the head of the reverse thrust screw. The diameter of the reverse thrust screw is equal to the diameter of the extruder screw, and the length of the reverse thrust screw is 4 times the diameter of the extruder screw. A heating temperature control device is arranged in the screw barrel, and the air outlet of the reverse thrust exhaust device is connected to the first vacuum system. The exhaust port of the reverse thrust exhaust device is provided with a detachable glass window for observing the operating status of the equipment.

[0017] Furthermore, the two vacuum exhaust ports are respectively connected to the second vacuum system.

[0018] Furthermore, a devolatilizer injection port is provided below the 8th section of the cylinder.

[0019] In a second aspect, the present invention discloses a method for extruding and blending aqueous ABS resin powder, based on the above-mentioned aqueous ABS resin powder extrusion and blending device.

[0020] Furthermore, a method for extruding and blending aqueous ABS resin powder comprises:

[0021] The ABS wet powder, SAN resin and additives are respectively fed into the same gravity flow conveying pipeline through a metering feeding unit for premixing to obtain a premix;

[0022] feeding the premix into an extruder, removing moisture from the premix and discharging it from a first vacuum system;

[0023] Blending and dispersing the premix from which water has been removed;

[0024] Adding a devolatilizer from a devolatilizer injection port to the premix after blending and dispersion to remove volatiles and discharge them from the second vacuum system;

[0025] The premix after volatile matter removal is pressurized and passed through a filter screen, then extruded from a die head, and then pelletized after water cooling to obtain ABS resin particles.

[0026] Further, before removing the moisture in the premix and discharging it from the first vacuum system, the method comprises:

[0027] The premix is ​​fed into the extruder from the material inlet of the first barrel, cooled in the first and second barrels, and compressed in the second barrel to form a sealing plug.

[0028] Furthermore, before removing the moisture in the premix and discharging it from the first vacuum system, the method further comprises:

[0029] The temperature of the first section barrel is controlled within 50℃, and the temperature of the second section barrel is controlled within 100℃.

[0030] Furthermore, the water content of the ABS wet powder is less than 20wt%.

[0031] Furthermore, the content of ABS wet powder in the premix is ​​less than 30wt%.

[0032] Further, the particle size of the rubber in the ABS wet powder is 0.05-10 microns;

[0033] The particle size of ABS wet powder is less than 5×5×5mm.

[0034] Furthermore, the additives include lubricants and antioxidants,

[0035] The lubricant includes one or a mixture of any two or more of N,N'-ethylenebisstearamide, oleamide, pentaerythritol distearate, pentaerythritol tetrastearate, ethylene glycol distearate, glycerol distearate, diethylene glycol distearate, magnesium stearate, calcium stearate, zinc stearate, fluoroelastomer, etc.;

[0036] The antioxidant includes one or a mixture of two or more of hindered phenols, phosphite antioxidants, thioesters, etc. in any proportion;

[0037] The lubricant and antioxidant in the premix are mixed in powder or granule form and then added, and the content of the auxiliary agent in the premix is ​​greater than 1.2wt%.

[0038] Further, the rotation speed of the extruder is 100-600 rpm, and the torque is 60-75%.

[0039] Further, the premix is ​​fed into an extruder, and moisture in the premix is ​​removed and discharged from a first vacuum system, comprising:

[0040] The moisture in the extruder is discharged to the first vacuum system through the reverse exhaust device;

[0041] The reverse thrust screw of the reverse thrust exhaust device has a rotation speed of 100-600 rpm.

[0042] Furthermore, the vacuum degree of the first vacuum system is controlled at 40-50 KPa.

[0043] Furthermore, the vacuum degree of the second vacuum system is controlled at 15-25 KPa.

[0044] Furthermore, the temperature of the barrel and the die of the 3rd to 10th sections is controlled at 210-230°C.

[0045] Technical effects and advantages of the present invention:

[0046] 1. The aqueous ABS resin powder extrusion blending process of the present invention solves the technical problems of continuous feeding of aqueous materials, water removal, resin blending, etc.

[0047] 2. The aqueous ABS resin powder extrusion blending process of the present invention is simple, the equipment structure is simple, can meet the requirements of continuous production, the equipment operation cost is low, and the process and equipment are reliable. The functional design of different areas of the extruder screw is fully utilized to achieve the process purposes of water separation, removal, blending and devolatilization, etc., each functional area is compactly connected, and the equipment is efficient. At the same time, the weightless feeding process is used for premixing, and the feeding and premixing functions are integrated to reduce the premixing equipment, save investment, simplify the process, and reduce the operation links.

[0048] 3. The aqueous ABS resin powder extrusion blending process of the present invention is suitable for the blending and extrusion of ABS wet powder with a certain water content, and can achieve the effect of dry powder blending and extrusion. At the same time, due to the effect of the devolatilization aid, the volatile content of the ABS resin can be significantly reduced, thereby improving the product quality.

[0049] 4. The aqueous ABS resin powder extrusion blending process of the present invention is suitable for continuous production in large-scale equipment, and is also suitable for the extrusion process of processing aqueous materials in small production lines of modification plants, meeting the processing requirements of recycled aqueous materials.

[0050] 5. Compared with the existing wet extrusion technology, the present invention improves the efficiency of wet extrusion by adding wet powder premixing, extruder dehydration, devolatilization blending design and reverse thrust exhaust device, etc. The functions of each part are closely connected, the length of the extruder screw is reduced, and the reliability of equipment operation is improved.

[0051] 6. Compared with the existing dry extrusion technology, the present invention expands the application scope of the production line and can process and produce water-containing materials, while the overall quality of the product is improved.

[0052] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of an aqueous ABS resin powder extrusion and blending device of the present invention. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] like Figure 1 As shown, the present invention provides an aqueous ABS resin powder extrusion and blending device, including a feeding structure and an extruder;

[0056] The extruder includes 10 sections of a barrel, a die head and a screw in the barrel, which are connected in sequence. The screw is used to convey and / or shear the material.

[0057] The feeding structure includes 3-5 metering feeding units and gravity flow conveying pipelines.

[0058] The metering and feeding unit includes a loss-in-weight scale and a discharge pipeline. The discharge pipeline is connected to the first section of the cylinder through the same gravity flow conveying pipeline and is used for continuous metering and adding of ABS wet powder, SAN resin and additives.

[0059] The gravity flow conveying pipeline forms an angle of 10-30 degrees with the horizontal plane. The material on the gravity flow conveying pipeline uses SAN resin as a carrier, and relies on friction and vibration of the gravity flow conveying pipeline to achieve premixing of ABS wet powder and SAN resin;

[0060] Each section of the barrel and the die head is provided with a temperature control unit for monitoring and adjusting the temperature;

[0061] The side wall of the 5th section cylinder is provided with a water vapor outlet, and the 7th and 9th sections cylinder are respectively provided with vacuum exhaust ports.

[0062] In order to eliminate the risk of high-temperature decomposition and combustion of ABS grafted powder caused by the extruder extruding the ABS grafted powder alone, releasing toxic gases, and to solve the problem of lack of SAN resin feeding to the extruder due to feeder failure, two metering feeding units can be set up to add SAN resin. Even if one of the metering feeding units fails, it can still ensure that a part of SAN resin is added to the extruder. At the same time, the two metering feeding units can also realize the feeding of two different SAN resins, thereby realizing the production of ABS resins with different properties.

[0063] In some embodiments of the present invention, the water vapor outlet is connected to a reverse thrust exhaust device, which includes a screw barrel, a reverse thrust screw and a variable frequency speed regulating device. The reverse thrust exhaust device is connected to the water vapor outlet through the screw barrel, the reverse thrust screw is arranged in the screw barrel, one end of the reverse thrust screw is connected to the variable frequency speed regulating device, and the variable frequency speed regulating device is used to drive the reverse thrust screw to rotate axially. The reverse thrust screw is close to the extruder and has a head with a small lead thread of the compression section. The material in the barrel only contacts the head of the reverse thrust screw. The diameter of the reverse thrust screw is equal to the diameter of the extruder screw. In this way, the size of the reverse thrust screw is the largest, the size of the exhaust channel is the largest, and the length of the reverse thrust screw is 4 times the diameter of the extruder screw, ensuring that the reverse thrust screw has a sufficiently large exhaust space. A heating and temperature control device is arranged in the screw barrel to prevent water vapor from condensing at the reverse thrust exhaust device. The air outlet of the reverse thrust exhaust device is connected to the first vacuum system, and the lateral exhaust port of the reverse thrust exhaust device is provided with a detachable glass window.

[0064] In some embodiments of the present invention, the seventh and ninth sections of the cylinder are respectively provided with vacuum exhaust ports, and the two vacuum exhaust ports are respectively connected to the second vacuum system.

[0065] In some embodiments of the present invention, a devolatilizer injection port is provided below the eighth section of the cylinder.

[0066] The working principle of the device is as follows: ABS wet powder, SAN resin and additives are quantitatively transported to the same feeding pipeline through multiple metering feeding units, and the ABS wet powder and SAN resin are premixed by friction between the materials and pipeline vibration, and then enter the first section of the barrel. By controlling the first and second sections of the barrel at a lower temperature, the position where the water in the ABS wet powder is vaporized is far away from the feeding port, and the temperature of the third to tenth sections of the barrel is controlled at 210-230℃. The water in the ABS wet powder begins to vaporize in large quantities at the third section of the barrel. Here, the material is melted and plasticized under the heating of the barrel and the shearing action of the extruder screw, and the polymer melt interface is continuously sheared by the screw. Cut and update, the separated water vapor enters the 5th section of the cylinder through the water vapor diffusion channel, and is discharged into the first vacuum system from the reverse thrust exhaust device. The material carried by the water vapor is pushed back to the 5th section of the cylinder through the reverse thrust screw to avoid blocking the water vapor outlet, and then the material is blended and dispersed in the 6th section of the cylinder, and then the material is sheared in the 8th section of the cylinder. At the same time, the devolatilizer is added through the devolatilizer injection port below the 8th section of the cylinder to assist the extruder in removing volatiles from the resin. The volatiles enter the second vacuum system from the exhaust ports of the 7th and 9th sections of the cylinder. The material after the volatiles are removed is pressurized by the screw and extruded from the die through the filter screen. After water cooling, it is pelletized to obtain ABS resin particles.

[0067] In a second aspect, the present invention further discloses a method for extruding and blending aqueous ABS resin powder, based on the above-mentioned aqueous ABS resin powder extrusion and blending device.

[0068] In some embodiments of the present invention, a method for extruding and blending aqueous ABS resin powder comprises:

[0069] The ABS wet powder, SAN resin and additives are respectively fed into the same gravity flow conveying pipeline through a metering feeding unit for premixing to obtain a premix;

[0070] feeding the premix into an extruder, removing moisture from the premix and discharging it from a first vacuum system;

[0071] Blending and dispersing the premix from which water has been removed;

[0072] Adding a devolatilizer from a devolatilizer injection port to the premix after blending and dispersion to remove volatiles and discharge them from a second vacuum system, wherein the devolatilizer includes desalted water or nitrogen;

[0073] The premix after volatile matter removal is pressurized and passed through a filter screen, then extruded from a die head, and then pelletized after water cooling to obtain ABS resin particles.

[0074] It should be noted that the present invention focuses on solving the technical problems of continuous and stable feeding of water-containing materials, separation and gasification of water in the extruder, removal of gasified water, blending and dispersion of blends, and removal of volatiles. The continuous and stable addition process of ABS wet powder adopts a loss-in-weight scale continuous metering feeding method to achieve metering and feeding of ABS wet powder. After the ABS wet powder enters the extruder, the water vapor will be vaporized by heat, and the vaporized water vapor will be reversed along the extruder feeding port, resulting in material bridging at the feeding port, and continuous production cannot be achieved. To solve this problem, the present invention takes measures from three aspects: First, premixing ABS wet powder with main components such as SAN resin to avoid uneven feeding of wet powder, fluctuation of water vaporization, and fluctuation of water vapor pressure in the extruder. By premixing, ABS wet powder and SAN resin can be added relatively evenly to avoid concentrated water vaporization, stabilize the water vapor pressure after vaporization, and thus improve the total water content of ABS wet powder used in this technology. First, the water content of ABS wet powder can reach up to 20%, and the total water content of materials added to the extruder can reach up to 7.5% (the maximum addition ratio of ABS wet powder is 30%). Premixing is to continuously feed into a feeding pipeline through multiple weight loss scales at the same time, and there is a certain friction contact between the materials to achieve premixing and dispersion of ABS wet powder in SAN resin. The key points of this process include: adding SAN resin and ABS wet powder to the same feeding pipeline at the same time, so that the two have the opportunity to contact in the pipeline; the feeding amount of SAN resin is greater than the feeding amount of ABS wet powder, and the feeding pipeline first adds SAN resin, and then adds ABS wet powder, forming a feeding mode with SAN resin as the carrier; the feeding pipeline has a certain inclination angle, and the material has friction on the pipe wall, relying on friction and pipeline vibration to achieve premixing of ABS wet powder and SAN resin. If necessary, a vibration device can be set on the feeding pipeline to assist in the dispersion and mixing of materials. The second is to make the water vaporization point in the ABS wet powder away from the feeding port. The position of water vaporization is controlled by controlling the temperature of the extruder barrel. Usually, the first section of the barrel where the feeding port of the twin-screw extruder is located is not equipped with a heating device, only cooling water is passed, and no temperature display and control are set. The second section of the barrel is heated and controlled. In order to avoid premature vaporization of water, the present invention moves the vaporization point toward the forward direction of the extruder material, cancels the electric heating of the second section barrel, and simultaneously sets a temperature control unit at the first section and the second section barrel (the first section and the second section barrel are cooling water control systems), which can monitor the barrel temperature and cooling water flow rate, ensure that the temperature of the second section barrel is lower than 100°C, and prevent a large amount of water from vaporizing. By moving the water vaporization point backward, the resistance of the vaporized water returning from the feeding port is increased.The third is to design the screw combination to guide the direction of water vapor. In order to completely prevent the vaporized water from flowing back along the feeding port, the screw combination is designed. On the one hand, a reasonable compression ratio of the solid conveying section is set, the filling ratio of the feeding section is increased, and the solid material is used to form a sealing plug to increase the resistance to water vapor reflux; on the other hand, the screw combination after the vaporization point is designed to increase the water vapor diffusion channel and guide the water vapor to be discharged along the designed channel.

[0075] The water in the ABS wet powder begins to vaporize in large quantities at the third section of the extruder barrel. Here, the material is melted and plasticized under the heating of the barrel and the shearing action of the extruder screw. The polymer melt interface is constantly updated by the screw shearing. The water in the ABS wet powder vaporizes when it encounters heat, but the vaporized water cannot be completely separated and discharged, and is easily wrapped in the molten resin. In order to solve the technical problem of sufficient separation of vaporized water, three measures are taken. First, a reasonable water vapor diffusion channel is designed so that the separated water vapor can be discharged in time to avoid being sheared by the screw and wrapped in the resin again; second, the power of water vapor removal is increased, and the first vacuum system is set at the exhaust port to increase the power of water vapor removal; third, the screw shearing element is added to achieve sufficient update of the molten resin interface, ensure that all water can be separated from the resin, and solve the problem of large water vapor diffusion resistance in the molten resin. Through these measures, the water can be fully separated to avoid the unstable phenomena such as material strip shaking and strip blasting caused by water carried at the extruder die discharge. In the process of the separated water vapor leaving the extruder, the water vapor will bring the material out, causing the exhaust port to be blocked. For this reason, a reverse exhaust device is designed at the water vapor outlet of the 5th section of the barrel. The function of the reverse exhaust device is to discharge the water vapor and prevent the material from being discharged. The reverse exhaust device uses a twin screw with the same diameter as the extruder (so that the size of the reverse screw is maximized and the exhaust channel size is maximized). The length of the reverse screw is about 4D. The head of the screw is provided with a small lead thread of the compression section, and the other parts are large lead threads. The material in the extruder only contacts the head of the reverse screw. The reverse screw is connected to a variable frequency speed regulating device to ensure that it has enough speed to push the material back to the extruder. At the same time, in order to prevent water vapor from condensing at the reverse exhaust device, a heating temperature control device is provided on the screw barrel. The exhaust port of the reverse exhaust device is downward to prevent the condensed water from flowing back to the extruder, and a glass window that can be quickly removed is provided to facilitate observation of the operating status of the equipment. To avoid condensation of water vapor, the reverse screw and the exhaust port are as short as possible.

[0076] In some embodiments of the present invention, before removing moisture from the premix and discharging from the first vacuum system, the method comprises:

[0077] The premix is ​​fed into the extruder from the material inlet of the first barrel, cooled in the first and second barrels, and compressed in the second barrel to form a sealing plug.

[0078] In some embodiments of the present invention, before removing moisture from the premix and discharging from the first vacuum system, the method further comprises:

[0079] The temperature of the first section barrel is controlled within 50°C, and the temperature of the second section barrel is controlled within 100°C.

[0080] In some embodiments of the present invention, the water content of the ABS wet powder is less than 20 wt %.

[0081] In some embodiments of the present invention, the content of ABS wet powder in the premix is ​​less than 30 wt %.

[0082] In some embodiments of the present invention, the particle size of the rubber in the ABS wet powder is 0.05-10 microns;

[0083] The particle size of ABS wet powder is less than 5×5×5mm. The small particle size of ABS wet powder is conducive to the stable addition of wet powder to the extruder, as well as the stable and efficient removal of moisture in the extruder.

[0084] In some embodiments of the present invention, the auxiliary agent comprises a lubricant and an antioxidant.

[0085] The lubricant includes one or a mixture of any two or more of N,N'-ethylenebisstearamide, oleamide, pentaerythritol distearate, pentaerythritol tetrastearate, ethylene glycol distearate, glycerol distearate, diethylene glycol distearate, magnesium stearate, calcium stearate, zinc stearate, fluoroelastomer, etc.;

[0086] The antioxidant includes one or a mixture of two or more of hindered phenols, phosphite antioxidants, thioesters, etc. in any proportion;

[0087] The lubricant and antioxidant in the premix are added after being mixed in powder or flake form, and the content of the auxiliary agent in the premix is ​​greater than 1.2wt%.

[0088] In some embodiments of the present invention, the speed of the extruder is 100-600 rpm, and the torque is 60-75%. Due to different torques, the material filling ratio in the extruder screw is different, so the extruder torque has a greater impact on the blending and dispersion effect and the extrusion dehydration effect.

[0089] In some embodiments of the present invention, the premix is ​​fed into an extruder, and the moisture in the premix is ​​removed and discharged from a first vacuum system, comprising:

[0090] The moisture in the extruder is discharged to the first vacuum system through the reverse exhaust device;

[0091] The reverse thrust screw of the reverse thrust exhaust device has a rotation speed of 100-600 rpm.

[0092] In some embodiments of the present invention, the vacuum degree of the first vacuum system is controlled at 40-50 KPa.

[0093] In some embodiments of the present invention, the vacuum degree of the second vacuum system is controlled at 15-25 KPa.

[0094] In some embodiments of the present invention, the temperature of the barrel and the die of the 3rd to 10th sections is controlled at 210-230°C.

[0095] In order to better illustrate the present invention, the following examples and comparative examples are provided.

[0096] The raw materials of each embodiment and comparative example are shown in Table 1 by weight.

[0097] Table 1

[0098]

[0099]

[0100] Example 1

[0101] Process: ABS wet powder (water content 12wt%, φ5mm×5mm granules), SAN resin (water content 0.5wt% or less, φ3mm×3mm granules) and additives (powder or granular EBS, antioxidant 168, antioxidant 1010) are measured by weight loss scale according to the ratio shown in Table 1, and continuously added to the extruder from the first section barrel. The water is vaporized to form water vapor through the heating and mechanical friction of the third section barrel of the extruder, and the water vapor is discharged through the reverse thrust exhaust device connected to the fifth section barrel. The materials are heated and mixed by the extruder, and nitrogen is added to the eighth section barrel to help the extruder remove volatiles from the resin. The molten resin after de-volatilization is pressurized by the extruder through the filter screen and extruded from the die head in strips. The extruded resin strips are water-cooled and pelletized to form ABS resin particles. The water vapor discharged from the fifth section barrel is extracted by the first vacuum system, and the volatiles carried by the de-volatilization agent are extracted by the second vacuum system connected to the seventh and ninth sections barrels.

[0102] Equipment status:

[0103] 1. The discharge pipeline diameter of the SAN resin metering and feeding unit is 300mm, and the discharge pipeline diameter of the ABS wet powder metering and feeding unit is 200mm. The diameter of the common feeding pipeline connecting the two is 450mm, and the common feeding pipeline is inclined at an angle of 15 degrees to the vertical direction.

[0104] 2. Extruder configuration: screw diameter 133mm, screw length-diameter ratio 40:1, 10-section barrel, the first section barrel is provided with a feed port, the side wall of the fifth section barrel is provided with a steam outlet, the seventh and ninth sections barrel are provided with exhaust ports upward, and the lower part of the eighth section barrel is provided with a devolatilizer injection port.

[0105] 3. Reverse thrust exhaust configuration, reverse thrust screw diameter 133mm, reverse thrust screw length-to-diameter ratio 4:1.

[0106] 4. Two vacuum systems, the water vapor outlet is connected to the first vacuum system, and the exhaust ports of the 7th and 9th sections of the cylinder are connected to the second vacuum system.

[0107] Process settings:

[0108] 1. Production load: the total feed rate of all raw materials is 7000 kg / h, and the distribution ratio of each group is set according to Table 1.

[0109] 2. The barrel temperature of each section of the extruder shall be set according to Table 2.

[0110] Table 2 Extruder temperature settings

[0111]

[0112] 3. The extruder screw speed is 400rpm and the torque is controlled below 75%.

[0113] 4. The screw barrel temperature of the reverse thrust exhaust device is 200°C, and the speed of the reverse thrust screw is 200rpm.

[0114] 5. The vacuum degree of the first vacuum system is 50 kPa, and the vacuum degree of the second vacuum system is 25 kPa.

[0115] 6. The die head pressure of the extruder is controlled at about 65 bar and the temperature is controlled at about 260°C.

[0116] In Example 1, the extruder was operated continuously for 24 hours at 7000 kg / h.

[0117] Example 2

[0118] The raw materials, equipment, process conditions, and operation process used in Example 1 are the same, and the extrusion production load is the same. The difference is that the amount of ABS wet powder added in Example 2 is increased. The specific formula is shown in Table 1.

[0119] Example 3

[0120] The raw materials, equipment, process conditions, operation process and formula used in Example 2 are the same, except that the extrusion production load of Example 3 is 4 tons / hour.

[0121] Example 4

[0122] The equipment, process conditions and operation process are the same as those in Example 2, except that two SAN resins with different melt flow rates are selected in Example 4. SAN1 is the same as the SAN resin in Example 2, and SAN2 is a high-flow SAN resin. SAN1:SAN2=10:90.

[0123] Example 5

[0124] The difference from Example 2 is that the water content of the ABS wet powder in Example 5 is 10%, and other raw materials, equipment and process conditions, operation process, formulation and other conditions are the same.

[0125] Example 6

[0126] The difference from Example 2 is that in Example 6, 1% desalted water is used as a devolatilizer, and other raw materials, equipment, process conditions, operation process, formulation and other conditions are the same.

[0127] Example 7

[0128] The difference from Example 2 is that the water content of the wet powder in Example 7 is 20%, and other raw materials, equipment and process conditions, operation process, formulation and other conditions are the same.

[0129] Example 8

[0130] The difference from Example 2 is that the vacuum degree of the first vacuum system and the second vacuum system of Example 8 is controlled at about 80 kPa, and other raw materials, equipment and process conditions, operating procedures, formulations and other conditions are the same.

[0131] Example 9

[0132] The difference from Example 2 is that the barrel temperatures of each section of the extruder in Example 9 are as shown in Table 3, and other raw materials, equipment and process conditions, operating procedures, formulations and other conditions are the same.

[0133] Table 3

[0134]

[0135]

[0136] Embodiment 10:

[0137] The difference from Example 2 is that in Example 10, the extruder speed is lower and the torque is controlled at about 75%. Other raw materials, equipment and process conditions, operation process, formulation and other conditions are the same.

[0138] Comparative Example 1

[0139] The process conditions and operation process are the same as those used in Example 2. Except for the ABS wet powder, other raw materials are the same. The specific formula is shown in Table 1. Comparative Example 1 uses ABS powder without water, and its formula is the same as that of Example 1 in terms of dry basis content.

[0140] The ABS dry powder used in Comparative Example 1 was dried in an air fluidized bed.

[0141] The extruder screw used in Comparative Example 1 has a diameter of 119 mm, an aspect ratio of 31.2, a screw speed of 400 rpm, and an extruder feed rate of 5000 kg / hour.

[0142] Comparative Example 2:

[0143] The process conditions and operation procedures are the same as those used in Example 7. Except for the ABS wet powder, other raw materials are the same. The specific formula is shown in Table 1. Comparative Example 2 uses ABS powder without water, and its formula is the same as that of Example 7 in terms of dry content.

[0144] The ABS dry powder used in Comparative Example 2 was dried in an air fluidized bed.

[0145] The extruder screw diameter used in Comparative Example 2 is 119 mm, the aspect ratio is 31.2, the extruder screw speed is 400 rpm, and the extruder feed rate is 5000 kg / hour.

[0146] Comparative Example 3:

[0147] Except for the ABS wet powder, other raw materials, process conditions, and operation procedures are the same as those in Implementation 2. The specific formula is shown in Table 1.

[0148] The water content of the ABS wet powder in Comparative Example 3 is 25%.

[0149] Comparative Example 4

[0150] The raw materials, equipment, process conditions, and operation procedures are the same as those in Implementation 2. The specific formula is shown in Table 1.

[0151] In Comparative Example 4, the amount of ABS wet powder added was increased from 30% to 50%.

[0152] Comparative Example 5

[0153] The raw materials, equipment, process conditions, and operation procedures are the same as those in Implementation 2. The specific formula is shown in Table 1.

[0154] In Comparative Example 5, the barrel temperature of the first and second sections of the extruder was set to 200°C.

[0155] Comparative Example 6

[0156] The raw materials, equipment, process conditions, and operation procedures are the same as those in Implementation 2. The specific formula is shown in Table 1.

[0157] In Comparative Example 6, the extruder torque is controlled at about 50%.

[0158] Comparative Example 7

[0159] Except for the ABS wet powder, other raw materials, equipment, process conditions, and operation procedures are the same as those in Implementation 2. The specific formula is shown in Table 1.

[0160] The ABS wet powder used in Comparative Example 7 is a wet powder of unqualified size that has been crushed in the upstream production process. Specifically, the length of the wet powder is about 1 cm, which is obviously much larger than the particle size of the wet powder in Example 2.

[0161] The ABS resin obtained in the above examples was injection molded by an injection molding machine to obtain various performance test specimens, the injection molding temperature was 200° C., and the injection molding pressure, speed, injection molding time and other process conditions were the same.

[0162] The properties of the ABS resin obtained in the example are shown in Table 4.

[0163] Table 4

[0164]

[0165]

[0166] The properties of the ABS resin obtained in the comparative example are shown in Table 5.

[0167] Table 5

[0168]

[0169]

[0170] It can be seen from the above data that the extrusion process of the present invention runs stably and the product performance is good, while the dry extrusion products of Comparative Examples 1 and 2 with the same rubber content have poor color and high residual content; the water content in the ABS wet powder of Comparative Example 3 increases, and the water vaporizes seriously during the feeding stage, resulting in backsteam at the feeding port, and the production cannot be continuously and stably operated for a long time; Comparative Example 4 has the same water content as Comparative Example 3, which exceeds the equipment capacity, resulting in unstable production; Comparative Example 5 increases the temperature of the ABS wet powder feeding section, resulting in the powder being easily vaporized in the feeding section, causing backsteam, and the production cannot be continuous and stable; Comparative Example 6 has an extruder speed that is too high, resulting in a low screw filling rate, the powder is sucked out under the action of vacuum, and the production fluctuates; Comparative Example 7 uses large-sized wet powder particles, which makes it difficult to remove moisture, the extrudate contains water, and stable production cannot be achieved.

[0171] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A water-containing ABS resin powder extrusion blending device, characterized in that: It includes a feeding structure and an extruder; The extruder comprises 10 sections of barrels, a die head and a screw in the barrel that are connected in sequence, and the screw is used to convey and / or shear materials; The feeding structure includes 3-5 metering feeding units and a gravity flow conveying pipeline. The metering and feeding unit includes a loss-in-weight scale and a discharge pipeline, and the discharge pipeline is connected to the first section of the cylinder through the same gravity flow conveying pipeline, and is used for continuous metering and adding ABS wet powder, SAN resin and additives; The gravity flow conveying pipeline forms an angle of 10-30 degrees with the horizontal plane. The material on the gravity flow conveying pipeline uses SAN resin as a carrier, and relies on friction and vibration of the gravity flow conveying pipeline to achieve premixing of ABS wet powder and SAN resin; A temperature control unit is provided in each section of the barrel and the die head for monitoring and adjusting the temperature; The side wall of the cylinder described in the 5th section is provided with a water vapor outlet, and the cylinders described in the 7th section and the 9th section are respectively provided with vacuum exhaust ports.

2. The aqueous ABS resin powder extrusion and blending device according to claim 1, characterized in that: The water vapor outlet is connected to a reverse thrust exhaust device, which includes a screw barrel, a reverse thrust screw and a variable frequency speed regulating device. The reverse thrust exhaust device is connected to the water vapor outlet through the screw barrel, the reverse thrust screw is arranged in the screw barrel, one end of the reverse thrust screw is connected to the variable frequency speed regulating device, and the variable frequency speed regulating device is used to drive the reverse thrust screw to rotate axially. The end of the reverse thrust screw close to the extruder is a head with a small lead thread of the compression section, and the material in the barrel only contacts the head of the reverse thrust screw. The diameter of the reverse thrust screw is equal to the diameter of the extruder screw, and the length of the reverse thrust screw is 4 times the diameter of the extruder screw. A heating temperature control device is arranged in the screw barrel, the air outlet of the reverse thrust exhaust device is connected to the first vacuum system, and the exhaust port of the reverse thrust exhaust device is provided with a detachable glass window.

3. The aqueous ABS resin powder extrusion and blending device according to claim 1, characterized in that: The two vacuum exhaust ports are respectively connected to the second vacuum system.

4. The aqueous ABS resin powder extrusion and blending device according to claim 1, characterized in that: A devolatilizer injection port is provided below the cylinder described in paragraph 8.

5. A method for extruding and blending aqueous ABS resin powder, characterized in that: The method is based on the aqueous ABS resin powder extrusion and blending device according to any one of claims 1 to 4.

6. The aqueous ABS resin powder extrusion blending method according to claim 5, characterized in that: include: The ABS wet powder, SAN resin and additives are respectively fed into the same gravity flow conveying pipeline through a metering feeding unit for premixing to obtain a premix; feeding the premix into an extruder, removing moisture from the premix and discharging it from a first vacuum system; blending and dispersing the premix from which water has been removed; Adding a devolatilizer from a devolatilizer injection port to the premix after blending and dispersion to remove volatiles and discharge them from a second vacuum system; The premix after volatile matter removal is pressurized and passed through a filter screen, and then extruded from a die head, and then pelletized after water cooling to obtain ABS resin particles.

7. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: Before removing the moisture in the premix and discharging it from the first vacuum system, the method comprises: The premix is ​​fed into the extruder from the material inlet of the first barrel, cooled in the first and second barrels, and compressed in the second barrel to form a sealing plug.

8. The aqueous ABS resin powder extrusion blending method according to claim 7, characterized in that: Before removing the moisture in the premix and discharging it from the first vacuum system, the method further comprises: The temperature of the first section barrel is controlled within 50℃, and the temperature of the second section barrel is controlled within 100℃.

9. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: The water content of the ABS wet powder is less than 20wt%.

10. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: The content of ABS wet powder in the premix is ​​less than 30wt%.

11. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: The particle size of the rubber in the ABS wet powder is 0.05-10 microns; The particle size of the ABS wet powder is less than 5×5×5 mm.

12. The method for extruding and blending aqueous ABS resin powder according to claim 6, characterized in that: The auxiliary agent comprises a lubricant and an antioxidant, The lubricant includes one or a mixture of any two or more of N,N'-ethylene bis stearic acid amide, oleic acid amide, pentaerythritol distearate, pentaerythritol tetrastearate, ethylene glycol distearate, glycerol distearate, diethylene glycol distearate, magnesium stearate, calcium stearate, zinc stearate, fluoroelastomer, etc. in any proportion; The antioxidant includes one or a mixture of two or more of hindered phenols, phosphite antioxidants, thioesters, etc. in any proportion; The lubricant and antioxidant in the premix are mixed in powder or granular form and then added, and the content of the auxiliary agent in the premix is ​​greater than 1.2wt%.

13. The method for extruding and blending aqueous ABS resin powder according to claim 6, characterized in that: The rotation speed of the extruder is 100-600 rpm, and the torque is 60-75%.

14. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: The method of feeding the premix into an extruder, removing moisture from the premix and discharging the premix from a first vacuum system comprises: The moisture in the extruder is discharged to the first vacuum system through the reverse exhaust device; The reverse thrust screw of the reverse thrust exhaust device has a rotation speed of 100-600 rpm.

15. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: The vacuum degree of the first vacuum system is controlled at 40-50 KPa.

16. The aqueous ABS resin powder extrusion blending method according to claim 6, characterized in that: The vacuum degree of the second vacuum system is controlled at 15-25 KPa.

17. The method for extruding and blending aqueous ABS resin powder according to claim 6, characterized in that: The temperature of the barrel and die of the 3rd to 10th sections was controlled at 210-230°C.

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