Improved EVA (Ethylene Vinyl Acetate) hot melt adhesive production system and application thereof in hot melt adhesive production

Abstract

The invention belongs to the technical field of hot melt adhesive production, and particularly relates to an improved EVA hot melt adhesive production system and application. The improved EVA hot melt adhesive production system comprises a stirring kettle, a melt pump, a filtering device, an extrusion die head, an underwater granulator, a dehydrator, a vibrating screen, a forced air drying system and the like, and further comprises an atomizing device which comprises an auxiliary solution storage tank, a metering pump, a valve FV and an atomizing nozzle. The atomizing nozzle is arranged on a transverse section of a pipeline I between the dehydrator and the vibrating screen; and a material outlet of the additive solution storage tank is connected with a material liquid inlet on the atomizing nozzle through the metering pump and the valve FV in sequence. Compared with the EVA hot melt adhesive production system before improvement, the improved EVA hot melt adhesive production system has the advantages that the cleaning time of scale deposit of the pipeline I is relatively prolonged by 0.67-1.56 times, and the time from bagging to hardening of EVA hot melt adhesive particles is relatively prolonged by 3.00-5.56 times.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hot melt adhesive production, and particularly relates to an improved EVA hot melt adhesive production system and application thereof in EVA hot melt adhesive production. BACKGROUND

[0002] In the traditional EVA hot melt adhesive production industry, due to the appearance characteristics of EVA hot melt adhesive, after being stored for a period of time after being bagged and stacked, relatively serious particle adhesion and even large block hardening phenomenon often occur, which affects the product quality and subsequent use. In the prior art, an additive is usually added dropwise to the EVA hot melt adhesive particles before they are bagged, so as to achieve the effect of preventing the EVA hot melt adhesive particles from adhering and being hardened. However, this adding method cannot guarantee that the surface of the EVA hot melt adhesive particles is attached by the additive, and cannot guarantee the uniformity of the attachment of the additive on the surface of the EVA hot melt adhesive particles, so the anti-hardening effect is poor. Meanwhile, the EVA hot melt adhesive particles are prone to adhere to the pipeline during production, causing the pipeline of the production system to be scaled, which needs to be cleaned frequently, increasing the production cost. SUMMARY

[0003] The purpose of the present application is to solve the technical problems of poor anti-hardening effect of EVA hot melt adhesive particles and scaling of the pipeline of the production system, and provide an improved EVA hot melt adhesive production system and application thereof in EVA hot melt adhesive production.

[0004] The technical solution of the present application is as follows: In a first aspect, the present application provides an improved EVA hot melt adhesive production system, which adopts the following technical solution: An improved EVA hot melt adhesive production system, comprising a stirring kettle, a bottom valve, a melt pump, a filtering device, an extrusion die, an underwater pelletizer, a constant-temperature water tank, a water circulating pump, a dehydrator, a vibrating screen and an air blowing drying system, further comprising an atomizing device; The bottom of the stirring kettle is provided with a discharge port, the discharge port at the bottom of the stirring kettle is connected with the melt pump, the filtering device and the extrusion die through a pipeline in sequence after passing through a valve FI, and the extrusion die is used for directly underwater pelletizing the filtered EVA hot melt adhesive melt after being extruded through the extrusion die; the cutting speed of the corresponding underwater pelletizer is controlled, so that EVA hot melt adhesive particles of a required size are obtained; The melt pump is used for pumping the EVA hot melt adhesive melt, the rotating speed of the melt pump is 26-28 r / min, and the conveying rate is 20-25 kg / min; The filtering device is provided with filtering holes with a diameter of 100-400 um, and the filtering device is arranged to filter the impurities in the production process or raw materials, so as to ensure the quality of the EVA hot melt adhesive particles; The outer ring of the extrusion die is provided with 60-80 holes, each hole is a 3mm±0.1mm round hole; The underwater pelletizer is further provided with a cooling water inlet and a material outlet; The constant temperature water tank is provided with a water inlet and a water outlet, the water inlet of the constant temperature water tank is connected with the water supply pipeline through a valve FII, the water outlet of the constant temperature water tank is connected with the cooling water inlet of the underwater pelletizer through a pipeline and a water circulating pump, so as to provide cooling water required by the underwater pelletizer during underwater cutting; The underwater pelletizer is a circular cutting, and the cutting rotation speed is 1000-1200r / min; The dewatering machine is provided with a material tangent inlet, a material outlet and a water outlet; The material outlet of the underwater pelletizer is connected with the material tangent inlet of the dewatering machine through a pipeline, so as to realize that the mixed material of the EVA hot melt adhesive particle crude product obtained by underwater cutting and the cooling water is discharged into the dewatering machine; The dewatering machine is a high-speed centrifuge with a rotation speed of 1200-1400r / min, which separates the EVA hot melt adhesive particle crude product and the cooling water used in the underwater cutting process by centrifugal separation; The water outlet of the dewatering machine is returned to the constant temperature water tank through a valve FIII, so as to realize the recycling and reuse of the cooling water used in the underwater pelletizer during production, thereby saving water resources; A branch pipeline is arranged on the pipeline between the valve FIII and the dewatering machine, the branch pipeline is connected to the factory waste collection place through a valve FIV, so that the waste liquid generated during the cleaning of the dewatering machine is treated in the unified three-waste treatment system of the factory; The material outlet of the dewatering machine is connected with the material inlet of the vibrating screen through a pipeline I; The vibrating screen is further provided with a material outlet; The pipeline I is divided into a horizontal section and a vertical section, the horizontal section of the pipeline I from the material outlet of the dewatering machine is downwardly inclined at an angle of 30-45°, the length of the horizontal section of the pipeline I is 1.0-1.2m, and the vertical section of the pipeline I is vertically corresponding to the material inlet of the vibrating screen, so that the vibrating screen receives the EVA hot melt adhesive particle crude product after dehydration by the dewatering machine; The air blowing drying system comprises an air blower and an air blowing dryer, and the air blowing dryer is provided with a tangent feeding inlet and a bottom discharge port; The material outlet of the vibrating screen is connected with the tangent feeding inlet of the air blowing dryer through a pipeline; The receiving tank of the EVA hot melt adhesive particles is arranged at the bottom discharge port of the air blowing dryer, and is used to receive the EVA hot melt adhesive particles after air drying by the air blowing dryer; A branch pipe is arranged on the pipe between the material outlet of the vibrating screen and the tangential inlet of the blast dryer, and is connected with the blower for providing working air for the blast dryer; The blower provides air at a pressure of 0.2-0.3 Mpa and a temperature of 37-39℃. The atomizing device is one, two, three or four sets, each set of the atomizing device comprising an auxiliary agent solution storage tank, a metering pump, a valve FV and an atomizing nozzle, the valve FV being a one-way valve. The atomizing nozzle of the atomizing device is arranged on the upper half of the pipe cross section of the pipe I at a position 0.8-0.9 m away from the material outlet of the dewatering machine, so that the EVA hot melt adhesive granules can be atomized by the auxiliary agent as soon as they enter the pipe I, thereby effectively preventing the EVA hot melt adhesive granules from being caked in the pipe I, and preventing the EVA hot melt adhesive granules from blocking the vibrating screen when passing through the vibrating screen, thereby improving the production continuity and production efficiency. The atomizing nozzle is connected with the pipe I by means of the external thread connection member arranged on the atomizing nozzle and the internal thread connection member welded on the pipe I. Preferably, the atomizing nozzle is of the model SK508 produced by Dongguan Hengxin Spray Technology Co., Ltd., and the inner diameter of the material liquid outlet of the atomizing nozzle body is 3 mm, and the inner diameters of the material liquid inlet and the air inlet of the atomizing nozzle body are both 10 mm. The inner diameter ratio of the material liquid outlet of the atomizing nozzle body to the inner diameter of the pipe I is 3:100. The installation angle of the atomizing nozzle on the pipe I is 30-90° according to the angle between the center line of the atomizing nozzle body and the direction of the material flow in the pipe I. The installation depth of the atomizing nozzle on the pipe I is -0.5-4.0 cm according to the length of the atomizing needle protruding from the inner wall of the pipe I. The auxiliary agent solution storage tank is provided with a discharge pipe, the inlet of the discharge pipe being 5-8 mm away from the bottom of the auxiliary agent solution storage tank, the outlet of the discharge pipe being connected with the material liquid inlet of the atomizing nozzle body through the metering pump and the valve FV in sequence, and the air inlet of the atomizing nozzle body being connected with the compressed air input pipe through the valve FVI. The valve FV is a one-way valve and is arranged close to the material liquid inlet of the atomizing nozzle body. The bottom of the auxiliary agent solution storage tank is provided with a blowdown port, which is connected to a factory blowdown collection through a pipeline by a valve FVII, so that the waste liquid generated during cleaning of the auxiliary agent solution storage tank enters the unified three-waste treatment system of the factory for treatment. The valve FV in the atomizing device is a one-way valve, which is installed and arranged close to the inlet of the material liquid of the atomizing nozzle body, and the purpose is to prevent the siphon phenomenon from causing abnormal flow of the auxiliary agent solution and affecting the stability of the product quality of the EVA hot melt adhesive particles.

[0005] By using the above technical scheme, the improved EVA hot melt adhesive production system can uniformly atomize the EVA hot melt adhesive particles, thereby effectively prolonging the time required for cleaning the accumulated dirt of the EVA hot melt adhesive particles on the pipeline I due to adhesion, and effectively prolonging the time from the start of stacking to the start of solidification during the storage process of the EVA hot melt adhesive particles. Compared with the original EVA hot melt adhesive production system (the EVA hot melt adhesive particles produced by the original EVA hot melt adhesive production system are treated with the same auxiliary agent and the same amount before being packaged), the time required for cleaning the accumulated dirt of the EVA hot melt adhesive particles on the pipeline I is relatively prolonged by 0.67-1.56 times, thereby relatively reducing the production cost and improving the production efficiency. At the same time, the time from the start of stacking to the start of solidification during the storage process of the EVA hot melt adhesive particles is relatively prolonged by 3.00-5.56 times, thereby improving the product quality.

[0006] Preferably, when the atomizing needle of the atomizing nozzle extends into the inner wall of the pipeline I and protrudes from the inner wall by a consistent length, the installation angle of the atomizing nozzle of the atomizing device on the pipeline I is 45-80° according to the included angle between the center line of the atomizing nozzle body of the atomizing nozzle and the direction of the material flow in the pipeline I. Further preferably, the center line corresponding to the material liquid nozzle of the atomizing nozzle and the direction of the material flow in the pipeline I are 45°.

[0007] Preferably, when the included angle between the center line of the atomizing nozzle body of the atomizing nozzle and the direction of the material flow in the pipeline I is consistent, the atomizing needle of the atomizing nozzle extends into the inner wall of the pipeline I and protrudes from the inner wall by a length of 2-3 cm. Further preferably, the installation depth of the atomizing nozzle of the atomizing device on the pipeline I is 3 cm according to the length by which the atomizing needle of the atomizing nozzle extends into the inner wall of the pipeline I and protrudes from the inner wall.

[0008] Preferably, the improved EVA hot melt adhesive production system adopts 2, 3 or 4 sets of atomization devices when the angle between the atomizing nozzle body center line of the atomizing nozzle and the material flow direction in the pipeline I is consistent, and the length of the atomizing needle of the atomizing nozzle protruding from the inner wall of the pipeline I is consistent, each set of atomization device includes one auxiliary solution storage tank, one metering pump, one valve FV and one atomizing nozzle, and the atomizing nozzle of each set of atomization device is arranged on the upper half pipe of the pipeline I at the position of 0.8-0.9m from the material outlet of the dehydrator of the pipeline I; Further preferably, the improved EVA hot melt adhesive production system adopts 4 sets of atomization devices; Further more preferably, when the atomization device is 4 sets, the installation angle of the atomizing nozzle of each set of atomization device is 45° according to the angle between the atomizing nozzle body center line of the atomizing nozzle and the material flow direction in the pipeline I, and the installation depth is 3cm according to the length of the atomizing needle of the atomizing nozzle 16 protruding from the inner wall of the pipeline I.

[0009] In the second aspect, the application provides the application of the above-mentioned improved EVA hot melt adhesive production system in EVA hot melt adhesive, which adopts the following technical scheme: The application of an improved EVA hot melt adhesive production system in EVA hot melt adhesive, the specific steps are as follows: (1) melt the raw materials used for preparing EVA hot melt adhesive in a stirred tank to obtain EVA hot melt adhesive melt; (2) load the additives used for preparing EVA hot melt adhesive into an additive solution storage tank, then add water, and stir uniformly to obtain an additive aqueous solution with a mass percentage concentration of 25-30%; The additive is an organic silicon-based anti-adhesive agent, preferably SH-3011 produced by Shanghai Chu Yijia Organic Silicon Material Co., Ltd.; The amount of the additive is 0.04-0.10% of the total weight of the raw materials used for preparing EVA hot melt adhesive; The application of the application, the use of the additive in the amount range has no effect on the use performance of the EVA hot melt adhesive particles produced by technical detection; In this application, only hot melt adhesive for bookbinding is used as an example, but the application of the additive in other hot melt adhesive products is not limited; (3) the EVA hot melt adhesive melt obtained in step (1) is filtered by a filter device under the action of a melt pump, then extruded through an extrusion die, and then cut into particles in a underwater pelletizer; The pump speed of the melt pump 2 is 26-28r / min, and the delivery capacity is 20-25kg / min; The temperature of the water in the constant temperature water tank is controlled to be 15-25℃ during the cutting process, and the rotating speed of the underwater cutting machine is 1000-1200r / min; (4) The mixture of the EVA hot melt adhesive granules and the cooling water obtained in step (3) is introduced into the dehydrator for centrifugal separation and dehydration to separate the EVA hot melt adhesive granules from the cooling water; The separated cooling water is introduced into the constant temperature water tank by the water circulating pump for recycling; The rotating speed of the centrifugal separation process of the dehydrator is controlled to be 1200-1400r / min; The flow rate of the EVA hot melt adhesive granules from the material outlet of the dehydrator is 0.35-0.45kg / s; (5) The valve FV and the valve FVI are opened, and the metering pump is started. The additive aqueous solution in the additive solution storage tank is introduced into the pipeline I between the dehydrator and the vibrating screen through the atomizing nozzle after the valve FV under the action of the metering pump, so as to spray the EVA hot melt adhesive granules after the dehydration in the dehydrator to obtain the atomized EVA hot melt adhesive granules; In the spraying process, the pressure of the compressed air introduced into the air inlet of the atomizing nozzle main body of the atomizing nozzle is 0.3-0.4Mpa, and the flow rate is 60mL / min. The flow rate of the additive solution introduced into the liquid inlet of the atomizing nozzle main body of the atomizing nozzle is 12-24mL / min; The flow rate of the additive solution introduced into the liquid inlet of the atomizing nozzle in the present application is only used as an example of the hot melt adhesive product for bookbinding. The specific flow rate of the additive solution is adjusted according to the corresponding EVA hot melt adhesive product prepared; (6) The atomized EVA hot melt adhesive granules in step (5) are introduced into the vibrating screen through the pipeline I for screening to remove the particles with a diameter greater than 7mm and the particles and fine powder with a diameter less than 5mm. The qualified EVA hot melt adhesive granules are dried by the air drying system, and the obtained EVA hot melt adhesive granule product is introduced into the receiving storage tank 12 of the EVA hot melt adhesive granules, and is bagged and stacked according to the product specifications; The diameter of the qualified EVA hot melt adhesive granules is 5-7mm; The air used in the air dryer of the air drying system is sent by the air blower. The air pressure of the air blower is 0.2-0.3Mpa, and the temperature is 37-39℃.

[0010] Adopting the technical scheme, the surface of the EVA hot melt adhesive particle finished product is uniformly attached by the auxiliary agent, so that the starting caking time of the EVA hot melt adhesive particle finished product in subsequent storage can be effectively prolonged. Further, after the surface of the EVA hot melt adhesive particle finished product is uniformly attached by the auxiliary agent, the fouling of the pipeline during production can be prevented, the production cost of fouling treatment is effectively reduced, and the production efficiency is relatively improved.

[0011] The beneficial technical effects of the present application An improved EVA hot melt adhesive production system of the present application only increases an atomizing device in the original EVA hot melt adhesive production system. The precise metering of the auxiliary agent is realized by the use of the metering pump in the added atomizing device. The installation position, installation angle, and the length of the atomizing needle of the atomizing nozzle of the atomizing device extending into the pipeline I between the dewatering machine and the vibrating screen are synergistically enhanced, so that the auxiliary agent mist is fully attached to the surface of the EVA hot melt adhesive particles, thereby improving the technical problems of fouling of the pipeline I of the EVA hot melt adhesive production system and poor anti-caking effect of the EVA hot melt adhesive particles. Compared with the EVA hot melt adhesive production system without improvement (without adding an atomizing device, using the same auxiliary agent and the same amount of auxiliary agent to process the obtained EVA hot melt adhesive particles before bagging the EVA hot melt adhesive particles), the fouling cleaning time of the pipeline I is relatively prolonged by 0.67-1.56 times, thereby relatively reducing the production cost and improving the production efficiency; the time from the start of bagging and stacking to the start of caking during the storage of the EVA hot melt adhesive particles is relatively prolonged by 3.00-5.56 times; Further, the improved EVA hot melt adhesive production system of the present application can effectively prolong the fouling cleaning time of the pipeline I and the time from the start of bagging and stacking to the start of caking of the EVA hot melt adhesive particle product. In addition, due to the use of the metering pump in the atomizing device, the automatic and precise metering of the auxiliary agent can be realized. Under the premise of a specified amount of auxiliary agent, the quality of the EVA hot melt adhesive particle product will not be affected by the addition of the auxiliary agent. In addition, after one and a half years of product application by the customer, it is also verified that the addition of the auxiliary agent does not affect the quality of the EVA hot melt adhesive particle product.

[0012] Further, the improved EVA hot melt adhesive production system of the present application also has the advantages of simple operation and safe and reliable production process. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1, the production process flow diagram of the improved EVA hot melt adhesive production system of Example 1, wherein 1 is a stirred tank, 2 is a melt pump, 3 is a filter device, 4 is an extrusion die, 5 is an underwater pelletizer, 6 is a constant temperature water tank, 7 is a water circulating pump, 8 is a dewatering machine, 9 is a vibrating screen, 10 is a blower, 11 is a forced air dryer, 12 is a receiving tank for EVA hot melt adhesive particles, 13 is an additive solution tank, 14 is a metering pump, 15 is a valve FV, 16 is an atomizing nozzle, 17 is a discharge valve FI, 18 is a valve FII, 19 is a valve FIII, 20 is a valve FIV, 21 is a valve FVI, and 22 is a valve FVII; Figure 2 , the production process flow diagram of the EVA hot melt adhesive production system without using an atomizing device in the control example, wherein 1 is a stirred tank, 2 is a melt pump, 3 is a filter device, 4 is an extrusion die, 5 is an underwater pelletizer, 6 is a constant temperature water tank, 7 is a water circulating pump, 8 is a dewatering machine, 9 is a vibrating screen, 10 is a blower, 11 is a forced air dryer, 12 is a receiving tank for EVA hot melt adhesive particles, 17 is a discharge valve FI, 18 is a valve FII, 19 is a valve FIII, and 20 is a valve FIV; Figure 3 , the arrangement diagram of two atomizing nozzles 16 of two sets of atomizing devices in Example 2 on the pipe I cross section of pipe I; Figure 4 , the arrangement diagram of three atomizing nozzles 16 of three sets of atomizing devices in Example 3 on the pipe I cross section of pipe I; Figure 5 , the arrangement diagram of four atomizing nozzles 16 of four sets of atomizing devices in Example 4 on the pipe I cross section of pipe I. DETAILED DESCRIPTION

[0014] The present application will be further described below by specific examples and in conjunction with the drawings, but the present application is not limited thereto.

[0015] The model and manufacturer information of the special equipment used in the embodiments of the present application are as follows: Device name Model Manufacturer information Stirred tank HT250L Linyi Haixin Chemical Equipment Co., Ltd. Melt pump MP-M-2500CC Zhengzhou Haikai Melt Pump Co., Ltd. Filter device HK-DP-2R-250 Zhengzhou Haikai Melt Pump Co., Ltd. Extrusion die 012 Suzhou Demagi Precision Tool Co., Ltd. Underwater pelletizer KSFM-2000 Taizhou Kefei Rubber and Plastic Machinery Co., Ltd. Dehydrator KSFM-2000 Taizhou Kefei Rubber and Plastic Machinery Co., Ltd. Vibrating screen ZS-820 Xinxiang Tuowei Machinery Manufacturing Co., Ltd. Atomizing nozzle SK508 Dongguan Hengxin Spray Technology Co., Ltd. Metering pump CT-005-10 Dongguan Hongqiang Environmental Protection Engineering Co., Ltd. The judgment method of the pipe I fouling cleaning time in the application embodiments of the present application: The improved EVA hot melt adhesive production system or the original EVA hot melt adhesive production system, according to the calculation of 8 batches per day (2h of continuous operation for each batch), 1.0-1.5h interval between each adjacent two batches, from the new use of pipe I (the pipe between the dewatering machine and the vibrating screen) or the calculation from the last cleaning end of pipe I, to the time when a layer of particle powder with a thickness of more than 0.5cm is accumulated on the inner wall of pipe I, which is recorded as the pipe I fouling cleaning time; The judgment method of the time when the bagged bookbinding hot melt adhesive particle product begins to set in the application embodiments of the present application: The time when the bagged bookbinding hot melt adhesive particle product begins to set is calculated from the EVA hot melt adhesive particle finished product of 25 kg per bag, and the time when the set block with a size of 5 cm*5 cm*5 cm or above is formed is recorded as the time when the bagging begins to set. Example 1

[0016] An improved EVA hot melt adhesive production system comprises a stirred tank, a discharge valve F1, a melt pump, a filtering device, an extrusion die, an underwater pelletizer, a constant temperature water tank, a water circulating pump, a dewatering machine, a vibrating screen and a blowing drying system, and further comprises a set of atomizing device; The production process flow diagram of the improved EVA hot melt adhesive production system is shown in Figure 1 , Figure 1 1 is the stirred tank, 2 is the melt pump, 3 is the filtering device, 4 is the extrusion die, 5 is the underwater pelletizer, 6 is the constant temperature water tank, 7 is the water circulating pump, 8 is the dewatering machine, 9 is the vibrating screen, 10 is the air blower, 11 is the air dryer, 12 is the receiving tank of EVA hot melt adhesive particles, 13 is the auxiliary solution storage tank, 14 is the metering pump, 15 is the valve FV, 16 is the atomizing nozzle, 17 is the discharge valve FI, 18 is the valve FII, 19 is the valve FIII, 20 is the valve FIV, 21 is the valve FVI, and 22 is the valve VII; The stirred tank 1 is provided with a feeding port and a bottom discharge port, and the bottom discharge port of the stirred tank 1 is connected with the melt pump 2, the filtering device 3 and the extrusion die 4 in sequence through the pipe after the discharge valve FI 13; The pump speed of the melt pump 2 is 26-28 r / min, and the conveying rate is 22 kg / min; The filtering hole diameter of the filtering device 3 is 200 um; The extrusion die 4 is provided with 60 holes, each hole is a circular hole with a straight diameter of 3 mm±0.1 mm; the extrusion die 4 is used to extrude the filtered EVA hot melt adhesive melt through the extrusion die 4, and then the extruded product is cut by the underwater pelletizer 5; by controlling the cutting speed of the corresponding underwater pelletizer 5, the EVA hot melt adhesive particle crude product with the required particle size can be obtained; The underwater pelletizer 5 is also provided with a cooling water inlet and a material discharge outlet; the underwater pelletizer 5 has a cutting rotating speed of 1000 r / min during operation; The constant temperature water tank 6 is provided with a water inlet and a water outlet; the water supply pipe is connected with the water inlet of the constant temperature water tank 6 through the valve FII 18; the water outlet of the constant temperature water tank 6 is connected with the cooling water inlet of the underwater pelletizer 5 through the pipe and the water circulating pump 7, so as to provide the cooling water required by the underwater pelletizer 5 for underwater pelletization; The dewatering machine 8 is provided with a material tangential inlet, a material outlet and a water outlet; the dewatering machine 8 is a high-speed centrifuge with a rotating speed of 1200r / min; The material outlet of the underwater pelletizer 5 is connected with the material tangential inlet of the dewatering machine 8 through a pipeline, so as to realize the discharge of the EVA hot melt adhesive particle crude product and water after underwater cutting into the dewatering machine 8; The water outlet of the dewatering machine 8 is connected with the constant-temperature water tank 6 through a valve FIII19, so as to realize the recycling of the cooling water used in the production process of the underwater pelletizer 5, thereby saving water resources; A branch pipeline is arranged on the pipeline between the valve FIII19 and the dewatering machine 8, and the branch pipeline is connected with a factory waste collection place through a valve FIV20, so that the waste liquid generated during the cleaning of the dewatering machine can be treated in the unified three-waste treatment system of the factory; The material outlet of the dewatering machine 8 is connected with the material inlet of the vibrating screen 9 through a pipeline I; The pipeline I is divided into a horizontal section and a vertical section, and the downward inclination of the horizontal section of the pipeline I is 45°, the length of the horizontal section of the pipeline I is 1m, and the outlet of the vertical section of the pipeline I is vertically corresponding to the material inlet of the vibrating screen 9; The air blowing drying system comprises an air blowing dryer 11 and an air blower 10, and the air blowing dryer 11 is provided with a tangential feeding inlet and a bottom discharge outlet; The vibrating screen 9 is also provided with a material outlet; The material outlet of the vibrating screen 9 is connected with the tangential feeding inlet of the air blowing dryer 11 through a pipeline; An EVA hot melt adhesive particle receiving tank 12 is arranged at the bottom discharge outlet of the air blowing dryer 11, and is used for receiving the EVA hot melt adhesive particles after air drying in the air blowing dryer 11; The air blower 10 is used for air supply to the air blowing dryer 11, and the air supply pressure is 0.25Mpa and the temperature is 37-39℃; A branch pipeline is arranged on the pipeline of the vibrating screen 9 and the air blowing dryer 11, and is close to the material outlet of the vibrating screen 9, the branch pipeline is connected with the air blower 10, and the branch pipeline is 0.2-0.3m away from the material outlet of the vibrating screen 9; The atomizing device comprises an auxiliary agent solution tank 13, a metering pump 14, a valve FV15 and an atomizing nozzle 16; The valve FV15 is a one-way valve, and is used for preventing the backflow of the auxiliary agent solution during the operation of the improved EVA hot melt adhesive production system; The atomizing nozzle 16 is arranged at the transverse section of the pipeline I from the material outlet of the dewatering machine 8 to the material inlet of the vibrating screen 9, and is arranged at the midpoint of the upper half of the pipeline cross section of the pipeline I near the material outlet of the dewatering machine 8 (i.e. at the midpoint of the upper half of the pipeline cross section of the pipeline I near the material outlet of the dewatering machine 8, i.e. at the middle position of the upper half of the pipeline cross section of the pipeline I near the material outlet of the dewatering machine 8); The atomizing nozzle 16 is connected to the pipeline I through the external thread connection member arranged on the atomizing nozzle 16 and the internal thread connection member welded on the pipeline I. The atomizing nozzle 16 is of the model SK508 and is produced by Dongguan Hengxin Spray Technology Co., Ltd. The inner diameter of the material liquid outlet of the atomizing nozzle body of the atomizing nozzle 16 is 3 mm, and the inner diameters of the material liquid inlet and the air inlet of the atomizing nozzle body are both 10 mm. The inner diameter ratio of the material liquid outlet of the atomizing nozzle body of the atomizing nozzle 16 to the inner diameter of the pipeline I is 3:100. The installation angle of the atomizing nozzle 16 is 60° according to the included angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in the pipeline I. The installation depth of the atomizing nozzle 16 is 2.0 cm according to the length of the atomizing needle of the atomizing nozzle 16 protruding from the inner wall of the pipeline I. The discharge pipe is arranged in the auxiliary solution storage tank 13 of the atomizing device. The inlet of the discharge pipe is 8 mm away from the bottom of the auxiliary solution storage tank. The outlet of the discharge pipe is connected to the material liquid inlet of the atomizing nozzle body of the atomizing nozzle 16 in sequence through the metering pump 14 and the valve FV15. The air inlet of the atomizing nozzle body of the atomizing nozzle 16 is connected to the compressed air input pipeline through the valve FVI21. The valve FV15 is a one-way valve, and is arranged at a position 0.2-0.3 m away from the material liquid inlet of the atomizing nozzle body of the atomizing nozzle 16. The auxiliary solution storage tank 13 is provided with a sewage outlet. The sewage outlet is connected to the factory sewage collection through the pipeline and the valve FVII22, so that the waste liquid generated during the cleaning of the auxiliary solution storage tank can be treated in the unified three-waste treatment system of the factory. Comparative Example

[0017] An EVA hot melt adhesive production system without using an atomizing device, which is different from the example 1 in that it does not have an atomizing device, and is the same as the example 1 in other aspects. The production process flow diagram of the EVA hot melt adhesive production system without using an atomizing device is shown in Figure 2 Figure 2 ​M1 is a stirred tank, 2 is a melt pump, 3 is a filter device, 4 is an extrusion die, 5 is an underwater pelletizer, 6 is a constant temperature water tank, 7 is a water circulating pump, 8 is a dewatering machine, 9 is a vibrating screen, 10 is a blower, 11 is a forced air dryer, 12 is a receiving tank for EVA hot melt adhesive particles, 17 is a discharge valve F1, 18 is a valve FII, 19 is a valve FIII, and 20 is a valve FIV. Examples 2-4

[0018] An improved EVA hot melt adhesive production system, which is different from Example 1 only in that: The atomizing devices in Examples 2-4 are 2 sets, 3 sets, and 4 sets, respectively; each set of atomizing device includes an auxiliary agent solution tank 13, a metering pump 14, a valve FV 15, and an atomizing nozzle 16 as in Example 1; Each atomizing nozzle 16 is arranged on the upper half pipe of the pipe cross section of the pipe I at a distance of 0.9 m from the material outlet of the dewatering machine 8, and the arrangement of the atomizing nozzles of the 2 sets, 3 sets, and 4 sets of atomizing devices in Examples 2-4 on the upper half pipe of the pipe cross section of the pipe I is shown in Figs. Figure 3 , 4 , 5, respectively; Figure 3 Corresponding to Example 2, when the atomizing device is 2 sets, 2 atomizing nozzles are arranged on the upper half pipe of the pipe cross section of the pipe I at a distance of 0.9 m from the material outlet of the dewatering machine 8, and the angle between the center lines of the two atomizing nozzle bodies is 60°, and the two atomizing nozzles divide the upper half pipe of the pipe cross section of the pipe I into three equal parts; Figure 4 Corresponding to Example 3, when the atomizing device is 3 sets, each adjacent two atomizing nozzles are arranged on the upper half pipe of the pipe cross section of the pipe I at a distance of 0.9 m from the material outlet of the dewatering machine 8, and the angle between the center lines of the two atomizing nozzle bodies is 45°, and the three atomizing nozzles divide the upper half pipe of the pipe cross section of the pipe I into four equal parts; Figure 5 Corresponding to Example 4, when the atomizing device is 4 sets, each adjacent two atomizing nozzles are arranged on the upper half pipe of the pipe cross section of the pipe I at a distance of 0.9 m from the material outlet of the dewatering machine 8, and the angle between the center lines of the two atomizing nozzle bodies is 60°, and the four atomizing nozzles divide the upper half pipe of the pipe cross section of the pipe I into three equal parts. Examples 5-8

[0019] An improved EVA hot melt adhesive production system, which is different from Example 1 in that: The installation angle of the atomizing nozzle 16 on the transverse section of the pipeline I is 30°, 45°, 80°, and 90°, respectively, according to the angle between the center line of the atomizing nozzle body of the atomizing nozzle and the direction of the material flow in the pipeline I. Examples 9-14

[0020] An improved EVA hot melt adhesive production system, which is different from Example 1 in that: The length of the atomizing needle of the atomizing nozzle 16 protruding into the inner wall of the pipeline I is -0.5 cm (0.5 cm retracted into the inner wall), 0 cm, 1 cm, 3 cm, 3.5 cm, and 4 cm, respectively. Example 15

[0021] An improved EVA hot melt adhesive production system, which is different from Example 1 in that: The atomizing device is 4 sets, and the installation position of the atomizing nozzle 16 of each set of atomizing device on the pipeline I is the same as that of Example 4. The installation angle of each atomizing nozzle 16 on the transverse section of the pipeline I is 45°, according to the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the direction of the material flow in the pipeline I. The length of the atomizing needle of each atomizing nozzle 16 protruding into the inner wall of the pipeline I is 3 cm. Example 1

[0022] An improved EVA hot melt adhesive production system of Example 1 is used for the production of hot melt adhesive for bookbinding: The raw materials used for the preparation of the hot melt adhesive for bookbinding are as follows in terms of weight fraction: Amorphous α-olefin copolymer (Yingchuang Industrial Group 508) 18 parts Hydrogenated alicyclic hydrocarbon resin (Elken Mobil Corporation 5400) 21.5 parts Ethylene-methyl methacrylate copolymer (Sumitomo Chemical Industry Co., Ltd. 5022) 22 parts Pure monomer resin (Sannac Chemical Co., Ltd. SA85) 19 parts #64 paraffin wax (China Petroleum Chemical Group) 18 parts Titanium dioxide (Pangang Group Co., Ltd. R298) 1 part Antioxidant (Pangang Group Co., Ltd. Antioxidant R298) 0.5 parts The amount of the additive (organic silicon-based anti-sticking agent, SH3011, Shanghai Chu Yiqi Silicone Material Co., Ltd.) used for the preparation of the hot melt adhesive for bookbinding is 0.07 parts, i.e., the amount of the additive is 0.07% of the total weight of the raw materials used for the preparation of the hot melt adhesive for bookbinding. The hot melt adhesive for bookbinding is prepared by the following method: (1) melt all raw materials of the hot melt adhesive for bookbinding in the stirring kettle 1 to obtain the melt of the hot melt adhesive for bookbinding; (2) load the auxiliary into the auxiliary solution storage tank 13, then add water, and stir uniformly to obtain an auxiliary aqueous solution with a mass percentage concentration of 25%; (3) under the power action of the melt pump 2, the melt of the hot melt adhesive for bookbinding obtained in step (1) is sequentially filtered through the filter device 3, extruded through the extrusion die 4, and then enters the underwater pelletizer 5 for underwater cutting; The pump speed of the melt pump 2 is 26-28 r / min, and the conveying amount of the melt of the hot melt adhesive for bookbinding is 22 kg / min; The temperature of the cooling water in the constant-temperature water tank 6 is controlled to be 15°C during the cutting process, the cooling water in the constant-temperature water tank 12 is pumped into the underwater pelletizer 5 through the water circulating pump 7, and the cutting speed of the underwater pelletizer 5 during underwater cutting is 1000 r / min; (4) the mixture of the EVA hot melt adhesive granules crude product obtained after underwater cutting in step (3) and the cooling water is introduced into the dehydrator 8 for centrifugal separation and dehydration to realize the separation of the EVA hot melt adhesive granules crude product and the cooling water; The cooling water separated by the dehydrator 8 is returned to the constant-temperature water tank 6 through the valve FIII 19 for recycling; The centrifugal separation process of the dehydrator 8 is controlled at a speed of 1200 r / min; The flow rate of the EVA hot melt adhesive granules crude product when it comes out of the material outlet of the dehydrator 8 is 0.40 kg / s; (5) open the valves FV15 and FVI21, and start the metering pump 14, the auxiliary aqueous solution in the auxiliary solution storage tank 13 is sprayed into the pipeline I between the dehydrator 8 and the vibrating screen 9 through the atomizing nozzle 16 after the valve FV15 under the action of the metering pump 14, to spray the auxiliary on the hot melt adhesive granules crude product for bookbinding after dehydration in step (4) to obtain the atomized hot melt adhesive granules crude product for bookbinding; In the above spraying process, the compressed air input through the air inlet of the atomizing nozzle 16 has a pressure of 0.4 Mpa and a flow rate of 60 mL / min, and the auxiliary solution input through the liquid inlet of the atomizing nozzle 16 has a flow rate of 18 mL / min; (6) The bookbinding hot melt adhesive granules of step (5) are fed into the vibrating screen 9 through the pipeline I to remove the particles with a diameter greater than 7 mm and the particles and fine powder with a diameter less than 5 mm. The qualified bookbinding hot melt adhesive granules are dried by the air dryer 11 to obtain the bookbinding hot melt adhesive granules, which are then fed into the receiving tank 12 of the EVA hot melt adhesive granules and packed according to the specification of 25 kg / bag. The diameter of the qualified bookbinding hot melt adhesive granules is 5-7 mm. The air used by the air dryer 11 is supplied by the air blower 10, and the pressure of the supplied air is 0.25 MPa and the temperature is 38℃. Comparative Example

[0023] The bookbinding hot melt adhesive is produced by using the EVA hot melt adhesive production system of the comparative example. The raw materials used for preparing the bookbinding hot melt adhesive are the same as those of application example 1 in terms of the composition and content; and the additives used for preparing the bookbinding hot melt adhesive and the amount of the additives are the same as those of application example 1. The bookbinding hot melt adhesive is produced by using the EVA hot melt adhesive production system of the comparative example. The raw materials used for preparing the bookbinding hot melt adhesive are the same as those of application example 1 in terms of the composition and content; and the additives used for preparing the bookbinding hot melt adhesive and the amount of the additives are the same as those of application example 1. (1) The same as step (1) of application example 1 to obtain the melt of the bookbinding hot melt adhesive. (2) The same as step (2) of application example 1 to obtain the water solution of the additives with a mass percentage concentration of 25%. (3) The same as step (3) of application example 1. (4) The same as step (4) of application example 1. (5) The bookbinding hot melt adhesive granules of step (4) are fed into the vibrating screen 9 through the pipeline I to remove the particles with a diameter greater than 7 mm and the particles and fine powder with a diameter less than 5 mm. The qualified bookbinding hot melt adhesive granules are dried by the air dryer 11 and then fed into the receiving tank 12 of the EVA hot melt adhesive granules. Then, the water solution of the additives with a mass percentage concentration of 25% obtained in step (2) is added into the EVA hot melt adhesive granules to mix uniformly. Then, the EVA hot melt adhesive granules are packed according to the specification of 25 kg / bag. The diameter of the qualified bookbinding hot melt adhesive granules is 5-7 mm. The air used by the air dryer 11 is supplied by the air blower 10, and the pressure of the supplied air is 0.25 MPa and the temperature is 38℃. Application Examples 2-4

[0024] The bookbinding hot melt adhesive is produced by using the improved EVA hot melt adhesive production system of application examples 2-4. The raw materials used for preparing the hot melt adhesive for bookbinding are the same as those in application example 1 in terms of composition and content. The preparation process of the hot melt adhesive for bookbinding is the same as that in application example 1, except that the following is different: the qualified EVA hot melt adhesive particles are dried by a blast drying tower, and then are packed and stacked according to 25 kg / bag.

[0025] In each set of the atomization device in example 2, the pressure of the compressed air input into the air inlet of the atomization nozzle body of each atomization nozzle 16 is 0.4 Mpa, the flow rate is 60 mL / min, and the flow rate of the auxiliary agent solution input into the liquid inlet of the atomization nozzle body of the atomization nozzle 16 is 9 mL / min. The total flow rate of the auxiliary agent solution input into the liquid inlet of the atomization nozzle body of the two atomization nozzles 16 in the two sets of atomization devices is 18 mL / min.

[0026] In each set of the atomization device in example 3, the pressure of the compressed air input into the air inlet of the atomization nozzle body of each atomization nozzle 16 is 0.4 Mpa, the flow rate is 60 mL / min, and the flow rate of the auxiliary agent solution input into the liquid inlet of the atomization nozzle body of the atomization nozzle 16 is 6 mL / min. The total flow rate of the auxiliary agent solution input into the liquid inlet of the atomization nozzle body of the three atomization nozzles 16 in the three sets of atomization devices is 18 mL / min.

[0027] In each set of the atomization device in example 4, the pressure of the compressed air input into the air inlet of the atomization nozzle body of each atomization nozzle 16 is 0.4 Mpa, the flow rate is 60 mL / min, and the flow rate of the auxiliary agent solution input into the liquid inlet of the atomization nozzle body of the atomization nozzle 16 is 4.5 mL / min. The total flow rate of the auxiliary agent solution input into the liquid inlet of the atomization nozzle body of the four atomization nozzles 16 in the four sets of atomization devices is 18 mL / min. Application examples 5-14

[0028] A modified EVA hot melt adhesive production system in examples 5-14 is used for producing the hot melt adhesive for bookbinding. The raw materials used for preparing the hot melt adhesive for bookbinding are the same as those in application example 1 in terms of composition and content. The preparation process of the hot melt adhesive for bookbinding is the same as that in application example 1, except that the following is different: the qualified EVA hot melt adhesive particles are dried by a blast drying tower, and then are packed and stacked according to 25 kg / bag. Application example 15

[0029] Using the improved EVA hot melt adhesive production system of Example 15, the hot melt adhesive for bookbinding is produced: The raw materials used for preparing the hot melt adhesive for bookbinding are the same as those in Application Example 1 in terms of composition and content by weight percentage. The preparation process of the hot melt adhesive for bookbinding is the same as that of Application Example 1 except for the following differences, and the qualified EVA hot melt adhesive particles are finally obtained by air drying through the air drying tower and then packed and stacked according to 25Kg / bag. In each of the four sets of atomizing devices of Example 15, the compressed air with a pressure of 0.4Mpa and a flow rate of 60mL / min is input into the air inlet of the atomizing nozzle body of the atomizing nozzle 16, and the auxiliary solution enters the auxiliary solution inlet of the atomizing nozzle body of the atomizing nozzle 16 at a flow rate of 4.5mL / min. The total flow rate of the auxiliary solution entering the auxiliary solution inlet of the atomizing nozzle body of the four atomizing nozzles of the four sets of atomizing devices is 18mL / min.

[0030] According to the production of 8 batches per day (each batch is continuously operated for 2h), and the interval between each adjacent two batches is about 70min, the time required for treating the fouling of the improved EVA hot melt adhesive production system with atomizing devices and the pipeline I of the EVA hot melt adhesive production system without atomizing devices and without improvement, and the time from the start of packing the EVA hot melt adhesive particles to the start of setting of the hot melt adhesive for bookbinding in the preparation processes of the above-mentioned Application Examples 1-15 and Application Comparative Examples are as follows: Number of atomizing nozzles (pcs) Installation angle of atomizing nozzle (°) Installation depth of atomizing nozzle (cm) Time for scale treatment (days) Time from bagging start to start of hardening (days) Application Example 1 1 60 2.0 150 120 Application Control Example 0 / / 90 30 Application Example 2 2 60 2.0 180 150 Application Example 3 3 60 2.0 200 180 Application Example 4 4 60 2.0 210 184 Application Example 5 1 30 2.0 120 100 Application Example 6 1 45 2.0 160 145 Application Example 7 1 80 2.0 152 125 Application Example 8 1 90 2.0 147 118 Application Example 9 1 60 -0.5 120 100 Application Example 10 1 60 0 128 116 Application Example 11 1 60 1.0 142 135 Application Example 12 1 60 3.0 175 150 Application Example 13 1 60 3.5 148 138 Application Example 14 1 60 4.0 135 128 Application Example 15 4 45 3.0 230 197 From the data of Application Example 1 and Application Comparative Example in the above table, it can be seen that the improved EVA hot melt adhesive production system, due to the use of atomizing devices (using one set of atomizing device), relative to the original EVA hot melt adhesive production system without improvement (without using atomizing device), the fouling cleaning time of pipeline I is relatively prolonged by 0.67 times, and the time from the start of packing the hot melt adhesive particles for bookbinding to the start of setting is relatively prolonged by 3.00 times.

[0031] From the data of application example 1, application control example and application examples 2-4, it can be seen that when the length of the atomizing needle of the atomizing nozzle 16 extending into the pipeline I and protruding from the inner wall of the pipeline I is consistent, and the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 in the atomizing device and the material flow direction in the pipeline I is consistent, the improved EVA hot melt adhesive production system, which adopts the atomizing device (1, 2, 3 or 4 sets of atomizing devices are adopted in examples 1, 2-4, respectively), has relatively more prolonged pipeline I fouling cleaning time and time from the start of bagging and stacking of the hot melt adhesive particles for bookbinding to the start of solidification. In particular, in application example 4 adopting 4 sets of atomizing devices, the pipeline I fouling cleaning time and the time from the start of bagging and stacking of the hot melt adhesive particles for bookbinding to the start of solidification are relatively more prolonged.

[0032] From the data of application example 1, application examples 5-8 in the above table, it can be seen that when the length of the atomizing needle of the atomizing nozzle 16 extending into the pipeline I and protruding from the inner wall of the pipeline I is consistent, and the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 in the atomizing device and the material flow direction in the pipeline I is 45-80°, the improved EVA hot melt adhesive production system has relatively longer pipeline I fouling cleaning time and time from the start of bagging and stacking to the start of solidification. In particular, in application example 6, when the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in the pipeline I is 45°, the pipeline I fouling cleaning time and the time from the start of bagging and stacking to the start of solidification are relatively longer.

[0033] From the data of application example 1, application examples 9-14 in the above table, it can be seen that when the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in the pipeline I is consistent, and the length of the atomizing needle of the atomizing nozzle 16 extending into the pipeline I and protruding from the inner wall of the pipeline I is 2.0-3.0 cm, the improved EVA hot melt adhesive production system has relatively longer pipeline I fouling cleaning time and time from the start of bagging and stacking to the start of solidification. In particular, according to the application example 12, when the length of the atomizing needle of the atomizing nozzle 16 in the atomizing device extending into the pipeline I and protruding from the inner wall of the pipeline I is 3.0 cm, the improved EVA hot melt adhesive production system has relatively longer pipeline I fouling cleaning time and relatively longer time from the start of bagging and stacking to the start of solidification.

[0034] According to the data of the application example 15 and the application comparison example in the above table, it can be seen that the improved EVA hot melt adhesive production system with four sets of atomizing devices, the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 of each set of atomizing device and the material flow direction in the pipeline I is 45°, the length of the atomizing needle of the atomizing nozzle 16 extending into the pipeline I and protruding from the inner wall of the pipeline I is 3 cm, compared with the EVA hot melt adhesive production system without using the atomizing device, the pipeline I fouling cleaning time can be relatively prolonged by 1.56 times; the time from the start of bagging and stacking to the start of solidification during the storage of hot melt adhesive particles for bookbinding can be relatively prolonged by 5.56 times.

[0035] In summary, the improved EVA hot melt adhesive production system of the present application improves the pipeline fouling technical problem of the original EVA hot melt adhesive production system, relatively reduces the production cost, improves the production efficiency, and solves the technical problem of poor anti-settling effect of the EVA hot melt adhesive particles produced by the original EVA hot melt adhesive production system, which can effectively improve the anti-settling effect of the EVA hot melt adhesive particles.

[0036] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An improved EVA hot melt adhesive production system, comprising a dewatering machine and a vibrating screen, wherein the dewatering machine and the vibrating screen are connected by a pipe I; Its features It also includes an atomizing device, which includes an additive solution storage tank, a metering pump, a valve FV, and an atomizing nozzle; Pipeline I between the dewatering machine and the vibrating screen is divided into a horizontal section and a vertical section. The downward slope of the horizontal section of pipe I, which comes out of the material outlet of the dewatering machine, is 30-45°. The length of the horizontal section of pipe I is 1.0-1.2m. The vertical section of pipe I is perpendicular to the material inlet of the vibrating screen. The atomizing nozzle is located on the upper half of the cross section of pipe I in the transverse section, at a distance of 0.8-0.9m from the material outlet of the dewatering machine; The atomizing nozzle and pipe I are connected by a thread or flange. The atomizing nozzle includes an atomizing nozzle body and an atomizing needle. The atomizing nozzle body is provided with a liquid inlet, an air inlet and a liquid spray nozzle. The atomizing needle is located at the front end of the atomizing nozzle body and is positioned directly opposite the liquid spray nozzle of the atomizing nozzle body. The ratio of the inner diameter of the liquid spray nozzle body to the inner diameter of pipe I is 3:100; The installation angle of the atomizing nozzle is 30-90°, based on the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I. The installation depth of the atomizing nozzle is determined by the length of the atomizing needle of the atomizing nozzle extending into the inner wall of pipe I and protruding from the inner wall, which is -0.5 to 4.0 cm. In the atomizing device, the auxiliary agent solution storage tank is equipped with a discharge pipe. The inlet of the discharge pipe is 5-8mm away from the bottom of the auxiliary agent solution storage tank. The outlet of the discharge pipe is connected to the liquid inlet of the atomizing nozzle body after passing through a metering pump and valve FV in sequence. The air inlet of the atomizing nozzle body is connected to the compressed air input pipeline through valve FVI. The valve FV is a check valve; The bottom of the auxiliary agent solution storage tank is provided with a drain port, and valve FVII is connected to the drain port.

2. The improved EVA hot melt adhesive production system as described in claim 1, characterized in that... The atomizing nozzle, model SK508, is manufactured by Dongguan Hengxin Spray Technology Co., Ltd. The inner diameter of the liquid spray nozzle body is 3mm, and the inner diameters of the liquid inlet and air inlet of the atomizing nozzle body are both 10mm.

3. An improved EVA hot melt adhesive production system as described in claim 1, characterized in that... The atomizing device is available in 1, 2, 3 or 4 sets. Each atomizing device includes 1 auxiliary agent solution storage tank, 1 metering pump, 1 valve FV and 1 atomizing nozzle. When there is one atomizing device, the atomizing nozzle is installed on pipe I at the midpoint of the upper half of the cross section of pipe I, which is 0.8-0.9m away from the material outlet of the dewatering machine. When there are two atomizing devices, the two atomizing nozzles are arranged with the center lines of the nozzle bodies of the two atomizing nozzles at an angle of 60° on the upper half of the cross section of the pipe I, which is 0.8-0.9m away from the material outlet of the dewatering machine. The two atomizing nozzles divide the upper half of the pipe into three equal parts. When there are 3 atomizing devices, they are arranged and installed on the upper half of the cross section of the pipe I, which is 0.8-0.9m away from the material outlet of the dewatering machine, with the included angle of the center line of the main body of each two adjacent atomizing nozzles being 45°. The 3 atomizing nozzles divide the upper half of the pipe into 4 equal parts. When there are 4 atomizing devices, they are arranged and installed on the upper half of the cross section of the pipe I, with the angle between the center lines of the main body of each two adjacent atomizing nozzles being 60° and the distance from the material outlet of the dewatering machine being 0.8-0.9m. The 4 atomizing nozzles divide the upper half of the pipe into 3 equal parts.

4. An improved EVA hot melt adhesive production system as described in claim 3, characterized in that... The installation angle of the atomizing nozzle on pipe I is 45-80°, with the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I being 45-80°.

5. An improved EVA hot melt adhesive production system as described in claim 4, characterized in that... The installation angle of the atomizing nozzle on pipe I is 45°, with the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I being 45°.

6. An improved EVA hot melt adhesive production system as described in claim 4, characterized in that... The installation depth of the atomizing nozzle is 2-3 cm, meaning the atomizing needle of the nozzle extends into the inner wall of pipe I and protrudes beyond the inner wall.

7. An improved EVA hot melt adhesive production system as described in claim 6, characterized in that... The installation depth of the atomizing nozzle is defined as the length by which the atomizing needle of the atomizing nozzle extends into the inner wall of pipe I and protrudes beyond the inner wall, which is 3 cm.

8. An improved EVA hot melt adhesive production system as described in claim 4, characterized in that... The installation angle of the atomizing nozzle of each atomizing device on pipe I is 45°, with the center line of the atomizing nozzle body being 45° and the material flow direction in pipe I being 45°. The installation depth of the atomizing nozzle on pipe I is 3cm, with the atomizing needle of the atomizing nozzle extending into the inner wall of pipe I and protruding from the inner wall.

9. The application of the improved EVA hot melt adhesive production system as described in any one of claims 1-8 in the production of EVA hot melt adhesive, characterized in that... The specific steps are as follows: (1) Melt the raw materials used to prepare EVA hot melt adhesive in a stirring tank to obtain EVA hot melt adhesive melt material; (2) The additives used to prepare EVA hot melt adhesive are put into the additive solution storage tank, and then water is added. After stirring evenly, an aqueous solution of additives with a mass percentage concentration of 25-30% is obtained. The additive mentioned is an organosilicon anti-sticking agent, specifically SH-3011, manufactured by Shanghai Chuyijia Organosilicon Materials Co., Ltd. The amount of additive used is 0.04-0.10% of the total weight of the raw materials used in the preparation of EVA hot melt adhesive; (3) The EVA hot melt adhesive material obtained in step (1) is pumped by a melt pump and filtered by a filter device. The EVA hot melt adhesive material is then extruded through an extrusion die and entered into an underwater pelletizer for underwater pelletizing. The melt pump has a rotational speed of 26-28 r / min and a delivery rate of 20-25 kg / min; During the pelletizing process, the water temperature in the constant temperature water tank is controlled at 15-25℃, and the rotation speed of the underwater pelletizer is 1000-1200r / min; (4) The EVA hot melt adhesive granules obtained after underwater pelletizing in step (3) and the mixture of cooling water are fed into a dewatering machine for centrifugal separation and dewatering. The centrifugal separation process of the above-mentioned dehydrator is controlled at a speed of 1200-1400 r / min; The flow rate of the above-mentioned coarse EVA hot melt adhesive granules exiting the material outlet of the dewatering machine is 0.35-0.45 kg / s; (5) Open valves FV and FVI, start the metering pump. The auxiliary solution in the auxiliary solution storage tank is sprayed into the pipe I between the dewatering machine and the vibrating screen through the atomizing nozzle after passing through valve FV under the action of the metering pump. The EVA hot melt adhesive particles crude product after being dehydrated in the dewatering machine in step (4) is sprayed to obtain the atomized EVA hot melt adhesive particles crude product. During the above spraying process, the pressure of the compressed air input to the air inlet of the atomizing nozzle body is 0.3-0.4 MPa and the flow rate is 60 mL / min, and the flow rate of the auxiliary solution input to the liquid inlet of the atomizing nozzle body is 12-24 mL / min. (6) The atomized EVA hot melt adhesive particles in step (5) enter the vibrating screen through pipe I for screening. The EVA hot melt adhesive particles with a diameter of 5-7mm are screened and dried by the blower drying system. The finished EVA hot melt adhesive particles are then placed in the receiving tank of EVA hot melt adhesive particles and bagged and stacked according to the product specifications. The air used in the blower dryer of the blower drying system is supplied by a blower with a pressure of 0.2-0.3 MPa and a temperature of 37-39℃.

10. The application of the improved EVA hot melt adhesive production system as described in claim 9 in the production of EVA hot melt adhesive, characterized in that... The EVA hot melt adhesive mentioned is a hot melt adhesive used for bookbinding, and its preparation process is as follows: In step (2), the amount of additive used is 0.07% of the total weight of the raw materials used in the preparation of hot melt adhesive for bookbinding; In step (3), the speed of the melt pump is 26-28 r / min, and the delivery rate is 22 kg / min; During the pelleting process, the water temperature in the constant temperature water tank is controlled at 15℃, and the rotation speed of the underwater pelletizer is 1000r / min; In step (4), the centrifugal separation process of the dewatering machine is controlled at a speed of 1200 r / min; the flow rate of the coarse hot melt adhesive particles used for bookbinding when they come out of the material outlet of the dewatering machine is 0.40 kg / s; In step (5), the pressure of the compressed air input to the air inlet of the atomizing nozzle body is 0.4 MPa and the flow rate is 60 mL / min, and the flow rate of the additive solution input to the liquid inlet of the atomizing nozzle body is 18 mL / min. In step (6), the blower delivers air at a pressure of 0.25 MPa and a temperature of 38°C.

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