Plastic production system

Abstract

The utility model provides a plastic production system. The plastic production system comprises a first mixing device, a main pipeline and a second mixing device. The first mixing equipment is sequentially provided with a first feeding hole, a second feeding hole, a third feeding hole and a fourth feeding hole in the material flowing direction; the second feeding hole is connected with a melt feeding pipe which can be opened or closed and is used for inputting the melt of the first polymer; a third feed port and a mixed discharge port; the main pipeline comprises a first branch pipe and a second branch pipe which can be opened or closed, and the first branch pipe is connected with the third feeding hole and is used for inputting a melt of a second polymer into the third feeding hole; and the second mixing equipment is arranged at the downstream of the mixed discharge hole and the main pipeline, is connected with the mixed discharge hole through a discharge pipeline, and is connected with the main pipeline through a second branch pipe. According to the utility model, the polymer is directly and continuously blended and modified, and an additive can be added in the blending process of various polymerization kettles to more flexibly change and improve the product performance.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of plastic production system. BACKGROUND

[0002] At present, there are few reports on the modification method of special engineering plastics products prepared by continuous or intermittent method. The utility model provides a kind of method for on-line modification of special engineering plastic melt prepared by continuous or intermittent reactor, which can continuously or intermittently produce engineering plastic melt from the reactor, and deliver to the molding equipment through special feeding metering system to complete on-line continuous processing, while adding functional additives such as additives, fillers, etc. as needed, realizing on-line mixing, so as to prepare a plurality of modified engineering plastic products.

[0003] Engineering plastic modification refers to improving or improving the performance of engineering plastics by adding various additives, changing the morphology or structure of plastics, etc. such as density, hardness, precision, appearance, processability, transparency, mechanical properties, electromagnetic properties, chemical properties, corrosion resistance, aging resistance, wear resistance, thermal properties, flame retardancy, barrier properties, etc. The purpose is to meet the special requirements of material performance in specific application fields, while reducing cost and improving production efficiency. The method of plastic modification can be divided into physical method and chemical method. Among them, the physical method mainly improves its performance by adding substances or blending with other resins; the chemical method mainly modifies the morphology and structure by chemical reaction.

[0004] The manufacturing process of traditional engineering plastic modified products represented by patent CN114957979B relies on virgin granular material as starting material, and mainly realizes modification by adjusting screw process parameters as a single means. However, due to the batch feeding mode adopted in the process, the difference between batches is difficult to avoid, which directly leads to the inconsistency of product quality, specifically manifested as low physical property index. In addition, the granular raw material used in traditional technology must undergo a change from solid to molten state, i.e. remelting process, which not only increases energy consumption and production cost, but also involves high-temperature degradation, which may damage the physical and chemical performance index of the product, thereby reducing the product quality.

[0005] Patent application CN101016411A discloses a method for online modification of engineering plastics: melt polymer of certain molecular weight obtained by continuous polymerization is directly sent to a screw extruder, and appropriate additives are added according to product requirements, and the mixture is uniformly extruded by the screw extruder. This scheme is only suitable for modification of melt polymer produced by continuous polymerization, and a screw extruder with large processing capacity and good performance is required, which has high equipment cost and large floor area. It cannot perform blending modification operation. At the same time, the scheme does not optimize the material conveying metering device, and material is prone to accumulate in the pipeline during long-term operation of the equipment, causing impurities in the product, yellow spot material and black spot material.

[0006] Utility model patent CN1035546C discloses a method and device for directly and continuously modifying polymer melt, i.e. by separating a side stream melt from the melt stream to be modified, dispersing the additives previously added to the melt in a specially designed screw extruder, and then mixing the additive melt collection with the melt stream to be modified. This scheme can only be used for additive modification and cannot perform blending modification operation of multiple polymers. The scheme does not optimize the material conveying metering device, and material is also prone to accumulate in the pipeline during long-term operation, causing impurities in the product, yellow spot material and black spot material. Utility model content

[0007] The utility model discloses a plastic production system to solve the technical problems of relying on the original granular material and being difficult to perform blending modification operation of multiple polymers in the prior art. The utility model makes the polymer directly and continuously blend and modify, and additives can be added in the blending process of multiple polymer kettles to more flexibly change and improve product performance.

[0008] To achieve the above object, the utility model adopts the following technical scheme:

[0009] Firstly, the utility model provides a plastic production system, which comprises a first mixing device, a main pipeline and a second mixing device.

[0010] The first mixing device is sequentially provided with a first feeding port, a second feeding port, a third feeding port and a mixed discharge port along the material flow direction.

[0011] The first feeding port is used for adding additives.

[0012] The second feeding port is connected with a melt feeding pipe that can be opened or closed and is used for inputting the melt of the first polymer.

[0013] The third feeding port and the mixed discharge port.

[0014] The main pipe comprises a first branch pipe and a second branch pipe, which are openable or closable, the first branch pipe is connected with the third feeding port and used for inputting the melt of the second polymer into the third feeding port;

[0015] The second mixing device is arranged downstream of the mixing discharge port and the main pipe, and is connected with the mixing discharge port through a discharge pipe and connected with the main pipe through the second branch pipe.

[0016] In the utility model, the first mixing device can be a screw extruder.

[0017] The screw extruder can be divided into 6-8 zones according to temperature; the first feeding port is arranged in the first zone along the material flow direction; the second feeding port is arranged in the second zone along the material flow direction; and the third feeding port is arranged in the third zone along the material flow direction.

[0018] The screw diameter of the screw extruder can be 50-150mm, for example, 75mm.

[0019] The length-diameter ratio of the screw of the screw extruder can be (20-50):1, preferably (30-40):1.

[0020] In the utility model, the second mixing device can be a dynamic mixer or a static mixer.

[0021] In the utility model, the discharge pipe can be provided with an injection valve.

[0022] The injection valve and the discharge pipe can be connected through flanges.

[0023] The mixing discharge port and the discharge pipe can be connected through flanges.

[0024] The second branch pipe and the feeding port of the second mixing device can be connected through flanges.

[0025] The first branch pipe and the third feeding port can be connected through flanges.

[0026] The first branch pipe and the main pipe can be connected through flanges.

[0027] The flange connection can adopt quick flanges.

[0028] The first feeding port can be connected with an additive feeding pipe.

[0029] The end of the additive feeding pipe, which is away from the first feeding port, can be connected with the discharge port of an additive feeding device. The additive feeding device can be provided with a metering module.

[0030] In the utility model, the one end of the melt feeding pipe far from the second feeding port can be connected with the discharge port of the first final polymerization reactor.

[0031] In the utility model, the discharge port of the first final polymerization reactor can be provided with a bottom valve.

[0032] Preferably, the bottom valve is an electric top-bottom valve.

[0033] In the utility model, the bottom valve can be connected with the flange of the melt feeding pipe.

[0034] Preferably, the bottom valve is connected with the flange of the elbow, and the elbow is connected with the melt feeding pipe.

[0035] In the utility model, the melt feeding pipe can be provided with a metering device.

[0036] Preferably, the metering device is a combination of a melt metering pump or a melt pump and a flow meter.

[0037] In the utility model, the inlet and outlet of the metering device can be preferably connected with the melt feeding pipe through flanges.

[0038] Preferably, the flange connection can adopt a quick flange.

[0039] In the utility model, the feeding port of the main pipeline can be connected with the discharge port of the second final polymerization reactor.

[0040] In the utility model, the discharge port of the second final polymerization reactor can be provided with a bottom valve.

[0041] Preferably, the bottom valve is an electric top-bottom valve.

[0042] In the utility model, the bottom valve can be connected with the flange of the main pipeline.

[0043] Preferably, the bottom valve is connected with the flange of the elbow, and the elbow is connected with the main pipeline.

[0044] Preferably, the flange connection can adopt a quick flange.

[0045] In the utility model, the main pipeline can be provided with a metering device.

[0046] Preferably, the metering device is a combination of a melt metering pump or a melt pump and a flow meter.

[0047] In the utility model, the inlet and outlet of the metering device can be preferably connected with the main pipeline through flanges.

[0048] In the utility model, the main pipeline can be perpendicular to the ground.

[0049] The second branch pipe can be provided with a cleaning outlet.

[0050] The cleaning outlet can be arranged between the connecting position of the discharge pipeline and the main pipeline and the second mixing device.

[0051] In the second aspect, the utility model provides a kind of plastic production method, it uses the plastic production system as described above, controls the opening or closing of the melt feed pipe and the first branch pipe, carries out the switching of at least following several kinds of working conditions:

[0052] The plastic production method includes the following steps in the working condition one that the melt feed pipe is opened and the first branch pipe is closed:

[0053] The additive is added to the first feed port, the first polymer melt is added to the second feed port, and the second polymer melt is added to the main pipeline.

[0054] The additive and the first polymer melt are uniformly mixed in the first mixing device, and the obtained mixture is discharged through the mixing discharge port and then enters the second mixing device through the discharge pipeline, and is uniformly mixed with the second polymer melt added to the second mixing device through the second branch pipe.

[0055] The plastic production method includes the following steps in the working condition two that the melt feed pipe and the first branch pipe are opened:

[0056] The additive is added to the first feed port, the first polymer melt is added to the second feed port, and the second polymer melt is added to the main pipeline.

[0057] The additive, the first polymer melt and part of the second polymer melt are uniformly mixed in the first mixing device, and the obtained mixture is discharged through the mixing discharge port and then enters the second mixing device through the discharge pipeline, and is uniformly mixed with the remaining second polymer melt added to the second mixing device through the second branch pipe.

[0058] The plastic production method includes the following steps in the working condition three that the first branch pipe is opened and the melt feed pipe is closed:

[0059] The additive is added to the first feed port, and the second polymer melt is added to the main pipeline.

[0060] The additive and the portion of the second polymer melt are mixed uniformly in the first mixing device, and the resulting mixture is discharged through the mixing outlet and into the second mixing device through the discharge conduit, where it is mixed uniformly with the remaining second polymer melt that is fed into the second mixing device through the second branch.

[0061] In the utility model, the first polymer can be polyamide. The polyamide is preferably PA6, PA66, PAMXD6, PAMXD10, PAMXD12, PA610, PA612, PA410 or PA66-PA610 copolymer.

[0062] In the utility model, the relative viscosity of the first polymer can be 2-2.7, for example 2.0-2.2.

[0063] In the utility model, the density of the first polymer at 25 DEG C. can be 1.20-1.25 g / mL, for example 1.21 g / mL.

[0064] In the utility model, the melting point of the first polymer can be 230-240 DEG C., for example 232-238 DEG C.

[0065] In the utility model, the second polymer can be polyamide. The polyamide is preferably PA6, PA66, PAMXD6, PAMXD10, PAMXD12, PA610, PA612, PA410 or PA66-PA610 copolymer.

[0066] In the utility model, the relative viscosity of the second polymer can be 2-3.2, for example 2.5-2.7 or 2.4-2.6.

[0067] In the utility model, the density of the second polymer at 25 DEG C. can be 1.12-1.15 g / mL.

[0068] In the utility model, the melting point of the second polymer can be 210-260 DEG C., for example 247-253 DEG C. or 217-223 DEG C.

[0069] In the utility model, the first polymer and the second polymer can be different polyamides.

[0070] In the utility model, the additive can be one or more of glass fiber, antioxidant, coupling agent, lubricant, montmorillonite, elastomer and anti-blocking agent, and optionally the first polymer and / or the second polymer.

[0071] Preferably, the glass fiber is short glass fiber or long glass fiber. The length of the short glass fiber is preferably 1-3 mm.

[0072] Preferably, the antioxidant is a phosphite antioxidant or a hindered phenolic antioxidant.

[0073] Preferably, the coupling agent is a silane coupling agent, such as KH550 or KH560.

[0074] Preferably, the elastomer is a nylon elastomer, a polyolefin elastomer, or a polyethylene octene co-elastomer.

[0075] Preferably, the anti-blocking agent is talc, diatomite, or silica.

[0076] Preferably, the lubricant is a polyethylene wax.

[0077] Preferably, the montmorillonite is a nano-montmorillonite.

[0078] In the working condition one or the working condition two, the mass flow ratio of the additive to the first polymer melt can be (0.1-2):1, such as 0.7:5.7, 1.5:6, or 8:5.7.

[0079] In the working condition one or the working condition two, the mass flow ratio of the second polymer melt introduced into the main pipeline to the first polymer melt can be (1-4):1, such as 15:5.7, 15:6, or 14.3:5.7.

[0080] In the working condition one, the mass flow of the second polymer melt introduced into the main pipeline can be greater than the mass flow of the first polymer melt.

[0081] Preferably, in the working condition two, the mass flow of the second polymer melt introduced into the main pipeline is greater than the mass flow of the first polymer melt, and the mass flow of the first polymer melt is greater than the mass flow of the second polymer melt introduced into the first branch pipeline.

[0082] In the working condition one, the mass flow ratio of the first polymer melt to the second polymer melt introduced into the first branch pipeline can be (0.5-3):1, such as 5.7:3.

[0083] In the working condition two or the working condition three, the mass flow ratio of the additive to the second polymer melt introduced into the first branch pipeline can be (0.1-3):1, such as 1.5:6, 8:3, or 8:5.7.

[0084] In the second or third working condition, the mass flow ratio of the second polymer melt introduced into the main pipeline to the second polymer melt introduced into the first branch pipe can be (1.5-6):1, preferably (2-6):1, for example 21:6, 15:3 or 20.7:5.7.

[0085] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the first zone on the screw extruder along the material flow direction can be 220-240 DEG C.

[0086] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the second zone on the screw extruder along the material flow direction can be 235-240 DEG C.

[0087] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the third zone on the screw extruder along the material flow direction can be 240-250 DEG C.

[0088] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the fourth zone on the screw extruder along the material flow direction can be 250-265 DEG C.

[0089] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the fifth zone on the screw extruder along the material flow direction can be 260-280 DEG C.

[0090] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the sixth zone on the screw extruder along the material flow direction can be 250-290 DEG C.

[0091] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the seventh zone on the screw extruder along the material flow direction can be 235-240 DEG C.

[0092] In the utility model, when the first mixing equipment is a screw extruder, the temperature of the eighth zone on the screw extruder along the material flow direction can be 220-230 DEG C.

[0093] In the utility model, when the first mixing equipment is a screw extruder, the rotational speed of the screw extruder can be 300-900 rpm, preferably 550-600 rpm.

[0094] In the utility model, when the first mixing equipment is a screw extruder, the vacuum degree of the screw extruder can be 0.05-0.09 MPa, preferably 0.05-0.07 MPa.

[0095] The plastic production method further comprises a fourth working condition that the melt feeding pipe and the first branch pipe are closed, and comprises the following steps:

[0096] The additive is added to the first feeding port, and the second polymer melt is added to the main pipe;

[0097] The additive is discharged through the mixing discharge port and then enters the second mixing device through a discharge pipe to be uniformly mixed with the second polymer melt added to the second mixing device through the second branch pipe.

[0098] On the basis of not violating the common sense of the art, the above-mentioned preferred conditions can be combined arbitrarily, that is, the preferred examples of the utility model are obtained.

[0099] The reagent and raw material used in the utility model are commercially available.

[0100] The positive progress effect of the utility model is that:

[0101] (1) The plastic production system of the utility model can flexibly adjust the use of related pipelines and valves, can quickly and conveniently obtain the required modified products, blended products, and reduce unqualified products; various different types of engineering plastic products can be simultaneously produced on one production line;

[0102] (2) The plastic production system of the utility model has a small overall volume, reduces the cost, can be used for intermittent and continuous production at the same time; the application field is wider, and after the plastic production system, it can not be directly fed into a pelletizer, but can be fed into a solvent type or melting type film casting machine to make a film;

[0103] (3) The plastic production system of the utility model has a metering function, can realize accurate metering of the modified melt in a molten state; the main pipe is vertical, utilizes the gravity to make the material be discharged as much as possible, prevents the material from gathering at the pipe turning part or "dead zone"; a mesh changer can be additionally installed on the metering device, filters the polyamide melt, and reduces the impurities contained in the melt;

[0104] (4) The plastic production system of the utility model can add the additive feeding device to the unqualified polymer chip for recycling, utilizes the irregular material generated in the unmodified polymer product, feeds the irregular material into the additive feeding device to be remelted in the feeding machine, and is used for the production of blended modified products;

[0105] (5) The plastic production system of the utility model, the pipeline flange between equipment can realize quick dismounting, for example, the top valve outlet, melt pump inlet and outlet, injection valve inlet and outlet of reactor and the inlet of mixer all adopt quick flange, and spare pipeline and flange which can be replaced are prepared simultaneously; when yellow and black spot material appears in product, the clean spare pipeline can be used to replace the material residual pipeline to continue production, and the material residual pipeline is treated by calcination and cleaning and the like to continue to be used as spare;

[0106] (6) The plastic production system of the utility model, a cleaning outlet can be arranged in the second branch pipe, cleaning liquid can be added in the reactor to complete cleaning, nitrogen gas is discharged at the same time, and the pipeline can be cleaned, and the nitrogen gas can be used as a nitrogen gas purging gas;

[0107] (7) The plastic production method of the utility model can realize switching operation of two polymer melt blending modification and single melt modification with additives, and the process index and range of raw materials can be selected. BRIEF DESCRIPTION OF DRAWINGS

[0108] Figure 1 It is a schematic diagram of the plastic production system in example 1.

[0109] The numbers in the drawing represent: additive feeding device 1, first terminal polymerization reactor 2, screw extruder 3, discharge pipeline 36, second terminal polymerization reactor 4, mixer 5, injection valve 6, main pipeline 7, first branch pipe 73 and second branch pipe 75. DETAILED DESCRIPTION

[0110] The utility model will be further illustrated by the following examples, but the utility model is not limited in the scope of the examples. The experimental method without specific conditions in the following examples is selected according to conventional method and condition or commodity instruction.

[0111] In the following examples and application examples, the basic conditions of raw materials used are as follows:

[0112] Glass fiber, length 1-3mm, diameter 9-13um, purchased from ZhenShi Group HengShi Fiber Base Industry Co., Ltd.

[0113] Antioxidant, model 1098;

[0114] Coupling agent, model KH560;

[0115] Lubricant, polyethylene wax, purchased from Honeywell, model A-C6A.

[0116] Elastomer, polyethylene octene copolymer elastomer (POE), purchased from American Dow Chemical Company, model 7467.

[0117] Anti-adhesion agent, silica, purchased from Sunway New Material Co., Ltd., model TAISIL 100.

[0118] Polyamide (MXD6) was prepared from m-xylylenediamine and adipic acid with a mass ratio of 100:110.53 in sequence through an amidation kettle, a prepolymerization kettle and a first terminal polycondensation reactor 2. The feeding temperature of m-xylylenediamine and adipic acid was 25-30℃. The temperature of the amidation reaction in the amidation kettle was 135℃, the residence time was 0.5h, and the pressure was 0.3MPa. The temperature of the prepolymerization reaction in the prepolymerization kettle was 230℃, the pressure was 0.6MPa, and the residence time was 2h. The temperature of the terminal polycondensation reaction in the first terminal polycondensation reactor 2 was 235-240℃, the pressure was-0.1MPa, and the residence time was 1.5h. MXD6: melting point 235±3℃, relative viscosity 2.1±0.1, density at 25℃ about 1.21g / mL.

[0119] PA66 was prepared from hexamethylenediamine and adipic acid and was finally obtained in the second terminal polycondensation reactor 4, molecular formula (C 10 H 22 N2O2) n , melting point 250±3℃, density at 25℃ 1.15g / mL, relative viscosity 2.5-2.7.

[0120] PA6 was prepared from caprolactam polymerization and was finally obtained in the second terminal polycondensation reactor 4, molecular formula (C6H 11 NO) n , melting point 220±3℃, density at 25℃ about 1.12g / mL, relative viscosity 2.5±0.1.

[0121] Relative viscosity: the ratio of the viscosity of a high molecular solution to the viscosity of a pure solvent at the same temperature, which is a dimensionless quantity. Reference standard: GB / T 12006.1-2009.

[0122] Example 1

[0123] A plastic production system, such as Figure 1 , comprises an additive feeding device 1, a first terminal polycondensation reactor 2, a screw extruder 3, a second terminal polycondensation reactor 4 and a mixer 5. The screw extruder 3 is provided with a first feeding port, a second feeding port, a third feeding port and a mixed discharging port in sequence along the material flow direction.

[0124] In this embodiment, the additive feeding device 1 is connected to the first feeding port of the screw extruder 3 through an additive feeding pipe. The first finishing reactor 2 is connected to the second feeding port of the screw extruder 3 through a melt feeding pipe. The second finishing reactor 4 is connected to the feeding port of the mixer 5 through the main pipe 7 and the second branch pipe 75. The mixing outlet of the screw extruder 3 is connected to the second branch pipe 75 through the outlet pipe 36, and the outlet pipe 36 is provided with an injection valve 6 for controlling the flow of the outlet pipe 36. Part of the injection valve 6 can be installed on the second branch pipe 75, but it does not control the second branch pipe 75. The main pipe 7 is connected to the third feeding port of the screw extruder 3 through the first branch pipe 73.

[0125] In this embodiment, the screw extruder 3 is divided into a first zone, a second zone, a third zone, a fourth zone, a fifth zone and a sixth zone along the material flow direction according to different temperatures. In other embodiments, there can be a seventh zone and an eighth zone. The first feeding port is arranged in the first zone. The second feeding port is arranged in the second zone. The third feeding port is arranged in the third zone. The outlet of the mixer 5 is connected to the feeding port of the cutting machine through a product pipe. In this embodiment, the mixer 5 is a static mixer. In other embodiments, the mixer 5 is a dynamic mixer. In this embodiment, the cutting machine is an underwater strip cutting granulator. In other embodiments, the cutting machine is a dry cutting granulator or a casting machine.

[0126] In this embodiment, the additive feeding device 1 is provided with a weighing module. In this embodiment, solid additives and / or solid product chips can be added to the additive feeding device 1, and the solid product chips can be a special-shaped material of unmodified product chips.

[0127] In this embodiment, a melt metering pump is arranged on the melt feeding pipe. In this embodiment, the main pipe 7 is provided with a melt metering pump. The melt metering pump has a metering function and can accurately meter the molten polymer. In this embodiment, a mesh changer is arranged on the outlet of the melt metering pump to filter the polymer melt and reduce impurities in the melt. In other embodiments, the melt metering pump can be replaced by a combination of a general melt pump, a flow meter and an adjusting valve.

[0128] In the embodiment, the discharge port of the first finishing reactor 2 is provided with an electric top and bottom valve, which is connected with the elbow through a quick flange. The elbow is connected with the melt feeding pipe. In the embodiment, the inlet and outlet of the melt metering pump on the melt feeding pipe are connected with the melt feeding pipe through a quick flange. In the embodiment, the discharge port of the second finishing reactor 4 is provided with an electric top and bottom valve, which is connected with the elbow through a quick flange. The elbow is connected with the main pipe 7. In the embodiment, the inlet and outlet of the melt metering pump on the main pipe 7 are connected with the main pipe 7 through a quick flange. In the embodiment, the main pipe 7 is connected with the feeding port of the mixer 5 through a quick flange. In the embodiment, the product pipe is connected with the discharge port of the mixer 5 through a quick flange. In the embodiment, the injection valve 6 and the discharge pipe 36 are connected through a quick flange. The mixing discharge port of the screw extruder 3 is connected with the discharge pipe 36 through a quick flange. The second branch pipe 75 is connected with the feeding port of the mixer 5 through a quick flange.

[0129] In the embodiment, the main pipe 7 is vertically arranged, so that the material is discharged as much as possible by gravity, and is prevented from gathering at the pipe bending part or the "dead zone". In other embodiments, the electric top and bottom valve can be replaced by other forms of bottom valve or discharge valve. In the embodiment, the pipe flanges between the devices can be quickly disassembled, and the prefabricated spare pipes and flanges that can be replaced are prepared. When yellow and black spots are found in the product, the clean spare pipe can be quickly replaced to continue production, and the material residual pipe can be used again after calcination and cleaning.

[0130] In the embodiment, a cleaning outlet can be arranged between the discharge pipe 36 and the second branch pipe 75 and the mixer 5. Ethylene glycol cleaning liquid can be added in the reactor to complete cleaning, and nitrogen gas is discharged, so that the bottom valve, the discharge pipeline, the melt metering pump and the injection valve can be cleaned, and nitrogen gas can be used as a blowing gas.

[0131] Embodiment 2

[0132] A control method of a plastic production system, which adopts the plastic production system in embodiment 1. The polymer melt of the first finishing reactor 2 can be mixed with the additives of the additive feeding device 1, and then the mixture is melted and mixed in the screw extruder 3 to form a modified melt in a molten state. The polymer melt of the second finishing reactor 4 is input into the mixer 5 through the main pipe 7 after being pressurized by the melt metering pump. The polymer melt of the second finishing reactor 4 can also be added into the screw extruder 3 through the first branch pipe 73. In general, the following working conditions can be divided:

[0133] Case one, the specific operation as follows: open the additive feeding pipe, melt feeding pipe, main pipe 7 and discharge pipe 36, close the first branch pipe 73. The first polymer melt in the first final polymerization reactor 2 is mixed with the additive of the additive feeding device 1, and then the mixture is melt-mixed by the screw extruder 3 to form the modified melt in the molten state; then, the second polymer melt in the second final polymerization reactor 4 is mixed with the modified melt flowing out of the discharge pipe 36 in the mixer 5.

[0134] Case two, the specific operation as follows: open the additive feeding pipe, melt feeding pipe, main pipe 7, discharge pipe 36 and first branch pipe 73. The first polymer melt in the first final polymerization reactor 2 and part of the second polymer melt in the second final polymerization reactor 4 are mixed with the additive of the additive feeding device 1, and then the mixture is melt-mixed by the screw extruder 3 to form the modified melt in the molten state; then, the remaining second polymer melt in the second final polymerization reactor 4 is mixed with the modified melt flowing out of the discharge pipe 36 in the mixer 5.

[0135] Case three, the specific operation as follows: open the additive feeding pipe, main pipe 7, discharge pipe 36 and first branch pipe 73, close the melt feeding pipe. The first final polymerization reactor 2 does not discharge. Part of the second polymer melt in the second final polymerization reactor 4 is mixed with the additive of the additive feeding device 1, and then the mixture is melt-mixed by the screw extruder 3 to form the modified melt in the molten state; then, the remaining second polymer melt in the second final polymerization reactor 4 is mixed with the modified melt flowing out of the discharge pipe 36 in the mixer 5.

[0136] Case four, the specific operation as follows: the melt feeding pipe and the first branch pipe 73 are closed, the additive is added to the first feeding port, and the second polymer melt is added to the main pipe 7; the additive is discharged through the mixing discharge port, and then enters the mixer 5 through the discharge pipe 36 to be uniformly mixed with the second polymer melt added to the mixer 5 through the second branch pipe 75.

[0137] Case five, the specific operation as follows: open the main pipe 7, close the additive feeding pipe, melt feeding pipe, discharge pipe 36 and first branch pipe 73. The polymer melt in the second final polymerization reactor 4 is directly sent to the pelletizer.

[0138] Application example 1: case one in example 2

[0139] The short glass fiber 457 kg, antioxidant 1098, 2.4 kg, coupling agent KH560, 15.4 kg and lubricant polyethylene wax 5.2 kg are first uniformly mixed by a mixer to form an additive, which is added to the additive feeding device 1 and added to the screw extruder 3 at a speed of 8 kg / min.

[0140] The polyamide (MXD6) outfeed from the first finishing reactor 2 was fed to the screw extruder 3 at a rate of 5.7 kg / min via a melt metering pump, the additives being fed in the first zone and the polyamide (MXD6) being fed in the second zone.

[0141] The screw extruder 3 had a capacity of over 830 kg / h, a screw diameter of 75 mm, a screw length-diameter ratio of 40:1, and the temperatures of the zones were: 220°C in the first zone, 235°C in the second zone, 250°C in the third zone, 265°C in the fourth zone, 280°C in the fifth zone, and 290°C in the sixth zone. The speed of rotation was set at 600 rpm for melt blending extrusion. The vacuum was -0.07 MPa. The additives and the polyamide (MXD6) in the molten state were mixed in the screw extruder 3 to form a modified melt.

[0142] The PA 66 obtained in the second finishing reactor 4 was discharged at a rate of 15 kg / min via a melt metering pump and mixed with the modified melt flowing from the outfeed conduit 36 in the mixer 5.

[0143] The resulting mixed product was sent to an underwater pelletizer for slicing, and the product obtained was in the form of cylinders φ 3.0 x 3.0 mm ± 5%.

[0144] Example 2: Case 1 in Example 2

[0145] The coupling agent KH560, 28.8 kg, the polyethylene octene copolymer elastomer 47.7 kg, the lubricant polyethylene wax 4.5 kg, the antioxidant 1098, 4.5 kg, and the anti-blocking agent silicon dioxide 4.5 kg were first mixed uniformly in a mixer to form additives, which were fed to the additive feeding device 1 and fed to the screw extruder 3 at a rate of 1.5 kg / min.

[0146] The polyamide (MXD6) outfeed from the first finishing reactor 2 was fed to the screw extruder 3 at a rate of 6 kg / min via a melt metering pump, the additives being fed in the first zone and the polyamide (MXD6) being fed in the second zone.

[0147] The screw extruder 3 had a capacity of over 450 kg / h, a screw diameter of 65 mm, a screw length-diameter ratio of 35:1, and the temperatures of the zones were: 240°C in the first zone, 240°C in the second zone, 240°C in the third zone, 250°C in the fourth zone, 260°C in the fifth zone, 250°C in the sixth zone, 240°C in the seventh zone, and 230°C in the eighth zone. The speed of rotation was set at 550 rpm for melt blending extrusion. The vacuum was -0.07 MPa. The additives and the polyamide (MXD6) in the molten state were mixed in the screw extruder 3 to form a modified melt.

[0148] The PA6 product obtained in the second terminal polymerization reactor 4 is mixed with the modified melt flowing out from the discharge pipe 36 in the mixer 5 at a speed of 15 kg / min through a melt metering pump.

[0149] The mixed product obtained is sent to an underwater pelletizer for slicing, and the product obtained is a cylindrical product with a diameter of 3.0 mm and a height of 3.0 mm ± 5%.

[0150] Application Example 3: Working Condition Two in Example 2

[0151] The difference from the application example 1 is that part of the PA66 obtained in the second terminal polymerization reactor 4 is introduced into the screw extruder 3 through the first branch pipe 73 at a speed of 3 kg / min, and is mixed with the additives and the polyamide (MXD6) in the molten state in the screw extruder 3 to form a modified melt, the additives being added from the first zone, the polyamide (MXD6) being added from the second zone, and the PA66 from the first branch pipe 73 being added from the third zone.

[0152] The remaining PA66 obtained in the second terminal polymerization reactor 4 is mixed with the modified melt flowing out from the discharge pipe 36 in the mixer 5 at a speed of 12 kg / min.

[0153] The PA66 discharged through the first branch pipe 73 can be premixed with the MXD6 and the additives in the screw extruder 3, so that the distribution of the additives and the MXD6 in the main PA66 material is better when mixed in the mixer 5, thereby making the overall performance of the material more excellent.

[0154] Application Example 4: Working Condition Three in Example 2

[0155] The difference from the application example 1 is that the first terminal polymerization reactor 2 does not discharge the product, and part of the PA66 obtained in the second terminal polymerization reactor 4 is introduced into the screw extruder 3 through the first branch pipe 73 at a speed of 5.7 kg / min, and is mixed with the additives in the screw extruder 3 to form a modified melt.

[0156] The remaining PA66 discharged from the main pipe 7 through the first branch pipe 73 is still discharged at a speed of 15 kg / min by adjusting the melt metering pump, and is uniformly mixed in the mixer 5.

[0157] Application Example 5: Working Condition Five in Example 2

[0158] The additive feeding device 1 and the first terminal polymerization reactor 2 do not discharge the product, and the PA66 obtained in the second terminal polymerization reactor 4 is discharged at a speed of 15 kg / min through a melt metering pump, and is sent to an underwater pelletizer for slicing, and the product obtained is a cylindrical product with a diameter of 3.0 mm and a height of 3.0 mm ± 5%.

[0159] Application Example 6: Working Condition One in Example 2

[0160] The difference from the application example 1 is that the product produced in the application example 5 is added into the additive feeding device 1, and the 40 kg of the irregular shaped material not meeting the size after granulation is added into the screw extruder 3 at a speed of 0.7 kg / min.

[0161] The PA66 obtained in the second terminal polymerization reactor 4 is discharged at a speed of 14.3 kg / min through the melt metering pump, and is mixed with the modified melt flowing out from the discharge pipeline 36 in the mixer 5.

[0162] Application example 7: working condition three in the example 2

[0163] The difference from the application example 2 is that the first terminal polymerization reactor 2 does not produce the discharge, and part of the PA6 obtained in the second terminal polymerization reactor 4 enters the screw extruder 3 at a speed of 6 kg / min through the first branch pipe 73, and is mixed with the additive in the screw extruder 3 to form the modified melt.

[0164] The remaining PA6 after the main pipeline 7 is branched off through the first branch pipe 73 is still discharged at a speed of 15 kg / min by adjusting the melt metering pump, and is uniformly mixed in the mixer 5.

[0165] After the above application examples 1-7 are operated for a period of time or a certain batch, generally for 1 to 2 weeks, ethylene glycol is added into the first terminal polymerization reactor 2 and the second terminal polymerization reactor 4 for cleaning, is discharged through the cleaning outlet on the main pipeline 7, the pipeline between the equipment is quickly disassembled through the quick flange, the pipeline is quickly replaced with a clean spare pipeline, and the production is continued, the pipeline with residual material is calcined at a high temperature above 330 ℃ and cleaned, and then is used again.

[0166] Comparative application example 1

[0167] The short glass fiber 457 kg, the antioxidant 1098, 2.4 kg, the coupling agent KH560, 15.4 kg, the lubricant polyethylene wax 5.2 kg, PA66 900 kg, and MXD6 342 kg are added into the mixer, and are stirred at 85 ℃ and a stirring speed of 250 r / min for 10 min to obtain a mixed material.

[0168] The mixed material is added into the double screw extruder through the automatic feeding device for mixing and extrusion, the double screw extruder has a processing capacity of more than 1725 kg / h, and then is cooled and granulated through the subsequent granulator.

[0169] Comparative application example 2

[0170] The coupling agent KH560, 28.8 kg, the polyethylene octene copolymer elastomer 47.7 kg, the lubricant polyethylene wax 4.5 kg, the antioxidant 1098, 4.5 kg, the anti-blocking agent silicon dioxide 4.5 kg, MXD6, 360 kg and PA6, 900 kg are mixed in a mixer, and then the mixture is added into a double screw extruder through an automatic feeding device for mixing and extruding, and then cooled and granulated through a subsequent granulator. The processing capacity of the double screw extruder is above 1350 kg / h.

[0171] Comparative application example 2-1

[0172] The difference from the comparative application example 2 is that the mixture (PA6, MXD6 and additives other than the former two) is added into the double screw extruder for extrusion through an automatic feeding device at a certain feeding speed of 22.5 kg / min. The processing capacity of the double screw extruder is above 1350 kg / h.

[0173] Comparative application example 3

[0174] The difference from the application example 1 is that only ordinary flanges are used for connecting the pipes between the devices, no screen changer is arranged, no cleaning outlet is arranged at the second branch pipe 75, and no cleaning, disassembly, calcination and other operations are performed. After two weeks of production, yellow and black spot materials are found in the product.

[0175] Comparative application example 4

[0176] The difference from the application example 1 is that only ordinary flanges are used for connecting the pipes between the devices, no screen changer is arranged, no cleaning outlet is arranged at the second branch pipe 75, and no cleaning, disassembly, calcination and other operations are performed. After four weeks of production, yellow and black spot materials are found in the product.

[0177] Effect implementation example

[0178] 1. Test object: plastic products obtained in the application examples 1-7 and the comparative application examples 1-4.

[0179] 2. Test method:

[0180] (1) Tensile strength: tested according to the test standard ASTM D638;

[0181] (2) Bending strength: tested according to ASTM / D790;

[0182] (3) Elongation at break: tested according to ISO 527-2 / 50;

[0183] (4) Melt index: tested according to ASTM D1238;

[0184] (5) Charpy notched impact strength: tested according to ASTM / D256;

[0185] (6) Color: the polymeric chips were not treated and directly tested by x-rite Ci7600 to test the difference;

[0186] (7) Water absorption: tested according to ISO 62.

[0187] (8) Oxygen transmission rate: tested according to ASTM D3985.

[0188] 3. Test results are shown in the following table:

[0189]

[0190]

[0191] Through the comparison of application example 1, application example 2 and comparative application example 1, comparative application example 2, it can be known that the polymeric melt and the additive can be continuously blended and modified on line.

[0192] Through the comparison of application example 1 and application example 3, it can be known that the distribution of each component in the product is better, the overall performance of the material is improved, the tensile strength and the bending strength of the product are higher, and the water absorption is lower by premixing the polymeric melt and the additive through the first branch pipe.

[0193] Through application examples 1-5, it can be known that the flexible production of various modified products and unmodified products can be realized.

[0194] Through the analysis of application example 6, it can be known that the recycling of the special-shaped material can be realized, and the performance index close to the original production process can be achieved.

[0195]

[0196] Through the comparison of application example 1 and comparative application examples 3-4, the impurities contained in the product can be reduced, and the color index of the product can be effectively improved.

Claims

1. A plastic production system, characterized by, It comprises a first mixing device, a main pipeline and a second mixing device; The first mixing device is sequentially provided with: a first feeding port for adding additives; a second feeding port connected with an openable or closable melt feeding pipe for inputting a melt of the first polymer; a third feeding port and a mixing discharge port; The main pipeline comprises a first branch pipe and a second branch pipe which are openable or closable, and the first branch pipe is connected with the third feeding port for inputting a melt of the second polymer into the third feeding port; The second mixing device is arranged downstream of the mixing discharge port and the main pipeline, and is connected with the mixing discharge port through a discharge pipeline and connected with the main pipeline through the second branch pipe.

2. The plastic production system according to claim 1, characterized in that, The first mixing device is a screw extruder; The screw extruder is divided into 6-8 temperature zones, the first feeding port is arranged in the first zone along the material flow direction, the second feeding port is arranged in the second zone along the material flow direction, and the third feeding port is arranged in the third zone along the material flow direction; The screw diameter of the screw extruder is 50-150 mm; The length-diameter ratio of the screw of the screw extruder is (20-50):

1.

3. The plastic production system according to claim 1, characterized in that, The second mixing device is a dynamic mixer or a static mixer; An injection valve is arranged on the discharge pipeline, and the injection valve and the discharge pipeline are connected by flanges; The mixing discharge port and the discharge pipeline are connected by flanges; The second branch pipe and the feeding port of the second mixing device are connected by flanges; The first branch pipe and the third feeding port are connected by flanges; The first branch pipe and the main pipeline are connected by flanges; The flange connection adopts quick flanges.

4. The plastic production system according to claim 1, characterized by The first feeding port is connected with an additive feeding pipe; The end of the additive feeding pipe away from the first feeding port is connected with a discharge port of an additive feeding device; A metering module is arranged on the additive feeding device.

5. The plastic production system according to claim 1, characterized by The end of the melt feeding pipe away from the second feeding port is connected with a discharge port of a first terminal polymerization reactor; The discharge port of the first terminal polymerization reactor is provided with a bottom valve; The bottom valve and the melt feeding pipe are connected by flanges; A metering device is arranged on the melt feeding pipe.

6. The plastic production system of claim 1, wherein, The feeding port of the main pipeline is connected with a discharge port of a second terminal polymerization reactor; The discharge port of the second terminal polymerization reactor is provided with a bottom valve; The bottom valve and the main pipeline are connected by flanges; A metering device is arranged on the main pipeline.

7. The plastic production system according to claim 5 or 6, characterized in that The bottom valve is an electrically operated top and bottom valve; The bottom valve is connected with an elbow flange, and the elbow is connected with the main pipeline; The metering device is preferably a melt metering pump or a combination of a melt pump and a flowmeter; The inlet and outlet of the metering device are preferably connected with the melt feeding pipe by flanges; The flange connection adopts quick flanges.

8. The plastic production system of claim 1, wherein, The main pipeline is perpendicular to the ground; A cleaning outlet is arranged on the second branch pipe, and the cleaning outlet is arranged between the connection of the discharge pipeline and the main pipeline and the second mixing device.

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