An improved EVA hot melt adhesive production system and its application in hot melt adhesive production

Abstract

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. The improved EVA hot melt adhesive production system comprises a stirring kettle, a melt pump, a filtering device, an extrusion die, an underwater pelletizer, a dewatering machine, a vibrating screen and a blast drying system, and further comprises an atomizing device. The atomizing device comprises an additive solution storage tank, a metering pump, a valve FV and an atomizing nozzle. The atomizing nozzle is installed on a transverse section of a pipeline I between the dewatering machine and the vibrating screen. A material outlet of the additive solution storage tank is connected to a material liquid inlet of the atomizing nozzle in sequence through the metering pump and the valve FV. Compared with the EVA hot melt adhesive production system before the improvement, the improved EVA hot melt adhesive production system relatively prolongs the pipeline I fouling cleaning time by 0.67-1.56 times, and prolongs the time from the beginning of bagging to the beginning of solidification of the EVA hot melt adhesive particles by 3.00-5.56 times.

Description

Technical Field

[0001] This application belongs to the field of hot melt adhesive production technology, and specifically relates to an improved EVA hot melt adhesive production system and its application in EVA hot melt adhesive production. Background Technology

[0002] In the traditional EVA hot melt adhesive production industry, due to the appearance characteristics of EVA hot melt adhesive, after being bagged, stacked, and stored for a period of time, severe particle adhesion and even large-scale caking often occur, affecting product quality and subsequent use. Current technology typically involves adding additives to the EVA hot melt adhesive granules before bagging to prevent adhesion and caking. However, this method cannot guarantee that the additives are evenly adhered to the surface of the EVA hot melt adhesive granules, nor can it guarantee the uniformity of the additive adhesion, resulting in poor anti-caking performance. Furthermore, during production, EVA hot melt adhesive granules easily adhere to pipelines, causing scaling in the production system, requiring frequent cleaning, and increasing production costs. Summary of the Invention

[0003] The purpose of this application is to provide an improved EVA hot melt adhesive production system and its application in EVA hot melt adhesive production, in order to solve the aforementioned technical problems such as poor anti-caking effect of EVA hot melt adhesive particles and scaling of pipelines in the production system.

[0004] The technical solution of this application is as follows:

[0005] In a first aspect, this application provides an improved EVA hot melt adhesive production system, which adopts the following technical solution:

[0006] An improved EVA hot melt adhesive production system includes a mixing tank, a bottom valve, a melt pump, a filter, an extrusion die, an underwater pelletizer, a constant temperature water tank, a water circulation pump, a dewatering machine, a vibrating screen, and a blower drying system, and also includes an atomizing device;

[0007] The bottom of the mixing tank is equipped with a discharge port. After passing through valve FI, the discharge port is connected to the melt pump, filter device and extrusion die head in sequence via pipeline. The extrusion die head extrudes the filtered EVA hot melt adhesive material and then directly passes it to the underwater pelletizer for underwater pelletizing. By controlling the cutting speed of the underwater pelletizer, coarse EVA hot melt adhesive particles with the required particle size can be obtained.

[0008] The melt pump is used to pump EVA hot melt adhesive melt material. The speed of the melt pump is 26-28 r / min and the conveying rate is 20-25 kg / min.

[0009] The filter pore diameter of the filter device is 100-400um. The purpose of the filter device is to filter out unmeltable impurities in the production process or raw materials to ensure the quality of EVA hot melt adhesive granules.

[0010] The outer ring of the extrusion die is provided with 60-80 holes, each hole being a round hole with a diameter of 3mm ± 0.1mm;

[0011] The underwater pelletizer is also equipped with a cooling water supply port and a material discharge port;

[0012] The constant temperature water tank is equipped with an inlet and an outlet. The inlet of the constant temperature water tank is connected to the water supply pipeline through valve FII, and the outlet of the constant temperature water tank is connected to the cooling water supply port of the underwater pelletizer through a water circulation pump to provide the cooling water required by the underwater pelletizer when it is cutting underwater.

[0013] The underwater pelletizer is a circular cutter with a cutting speed of 1000-1200 r / min;

[0014] The dewatering machine is equipped with a material tangential inlet, a discharge outlet, and a drain outlet;

[0015] The material outlet of the underwater pelletizer is connected to the material tangential inlet of the dewatering machine through a pipeline, so as to discharge the EVA hot melt adhesive granules obtained after underwater cutting and the mixture of cooling water into the dewatering machine together.

[0016] The dehydrator is a high-speed centrifuge with a rotation speed of 1200-1400 r / min, which separates the crude EVA hot melt adhesive particles from the cooling water used in the underwater pelletizing process by centrifugation.

[0017] The drain outlet on the dewatering machine flows back into the constant temperature water tank through valve FIII, so as to realize the recycling and reuse of the cooling water used in the underwater pelletizer during the production process, thereby saving water energy.

[0018] A branch pipeline is installed on the pipeline between valve FIII and the dewatering machine. This branch pipeline goes through valve FIV to the factory's wastewater collection point so that the waste liquid generated during the cleaning of the dewatering machine can be treated in the factory's unified waste treatment system.

[0019] The material outlet of the dewatering machine is connected to the material inlet of the vibrating screen via pipe I;

[0020] The vibrating screen is also equipped with a material outlet;

[0021] The aforementioned pipe I is divided into a horizontal section and a vertical section. The horizontal section of pipe I, which comes out of the material outlet of the dewatering machine, has a downward inclination of 30-45° and a length of 1.0-1.2m. The vertical section of pipe I is perpendicular to the material inlet of the vibrating screen so that the vibrating screen can receive the coarse EVA hot melt adhesive granules after dewatering by the dewatering machine.

[0022] The aforementioned blower drying system includes a blower and a blower dryer, the blower dryer being equipped with a tangential feed inlet and a bottom discharge outlet;

[0023] The material outlet of the vibrating screen is connected to the tangential feed inlet of the blower dryer via a pipeline;

[0024] The receiving tank for EVA hot melt adhesive granules is located at the bottom discharge port of the blower dryer and is used to receive the EVA hot melt adhesive granules after they have been dried by the blower dryer.

[0025] A branch pipe is installed on the pipe between the material outlet of the vibrating screen and the tangential feed inlet of the blower dryer, and 0.2-0.3m away from the material outlet of the vibrating screen. This branch pipe is connected to the blower to provide working air to the blower dryer.

[0026] The blower described above delivers air at a pressure of 0.2-0.3 MPa and a temperature of 37-39°C.

[0027] The atomizing device is 1, 2, 3 or 4 sets, and each atomizing device includes 1 auxiliary agent solution storage tank, 1 metering pump, 1 valve FV and 1 atomizing nozzle, wherein the valve FV is a one-way valve;

[0028] The atomizing nozzle of the atomizing device is located on the transverse section of pipe I from the material outlet of the dewatering machine to the material inlet of the vibrating screen, and on the upper half of the cross-section of pipe I, about 0.8-0.9m from the material outlet of the dewatering machine. This allows the coarse EVA hot melt adhesive particles to be quickly atomized by the additive after entering pipe I, thereby effectively preventing the coarse EVA hot melt adhesive particles from scaling in pipe I. In addition, when the EVA hot melt adhesive particles pass through the vibrating screen, it is less likely to clog the vibrating screen and cause production abnormalities, thereby improving production continuity and production efficiency.

[0029] The connection between the atomizing nozzle and the pipe I is achieved by connecting the external threaded connector on the atomizing nozzle with the internal threaded connector welded to the pipe I via a threaded connection; alternatively, a flange connection can be used.

[0030] Preferably, the atomizing nozzle is model SK508, manufactured by Dongguan Hengxin Spray Technology Co., Ltd., and the inner diameter of the liquid spray nozzle body is 3mm, while the inner diameter of the liquid inlet and air inlet of the atomizing nozzle body is 10mm.

[0031] The ratio of the inner diameter of the liquid nozzle on the atomizing nozzle body to the inner diameter of pipe I is 3:100.

[0032] The installation angle of the atomizing nozzle on pipe I is 30-90°, according to the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I.

[0033] The installation depth of the atomizing nozzle on pipe I is 0.5-4.0 cm, depending on the length of the atomizing needle of the atomizing nozzle extending into the inner wall of pipe I and protruding from the inner wall.

[0034] The atomizing device is equipped with a discharge pipe in the auxiliary agent solution storage tank. The inlet of the discharge pipe is 5-8 mm 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.

[0035] The valve FV is a one-way valve, and its installation position is close to the liquid inlet of the atomizing nozzle body;

[0036] The bottom of the auxiliary agent solution storage tank is equipped with a drain outlet, which is connected to the factory's wastewater collection point via valve FVII and pipeline, so that the waste liquid generated during the cleaning of the auxiliary agent solution storage tank can be treated in the factory's unified waste treatment system.

[0037] The valve FV in the atomizing device is a one-way valve, and it is installed near the liquid inlet of the atomizing nozzle body. The purpose is to prevent the siphon phenomenon from causing abnormal flow of the additive solution, which would affect the stability of the product quality of EVA hot melt adhesive particles.

[0038] By adopting the above technical solution, the improved EVA hot melt adhesive production system can atomize EVA hot melt adhesive particles uniformly. This effectively extends the time required to clean the scale buildup caused by EVA hot melt adhesive particles adhering to pipe I during the EVA hot melt adhesive production process. It also effectively extends the time from the start of palletizing to the start of caking during the storage of EVA hot melt adhesive particles. Compared with the original EVA hot melt adhesive production system (which produces crude EVA hot melt adhesive particles and then treats them with the same additives and dosage before bagging), the time required to clean scale buildup in pipe I is extended by 0.67-1.56 times, thereby relatively reducing production costs and improving production efficiency. At the same time, the time from the start of bagging and palletizing to the start of caking during the storage of EVA hot melt adhesive particles is extended by 3.00-5.56 times, thus improving product quality.

[0039] Preferably, when the atomizing needle of the atomizing nozzle extends into the inner wall of pipe I and protrudes from the inner wall for the same length, the installation angle of the atomizing nozzle of the atomizing device on pipe I is 45-80°, according to the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I.

[0040] More preferably, the centerline of the liquid spray nozzle is at a 45° angle to the direction of the material flow in pipe I.

[0041] Preferably, when the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I is consistent, the length of the atomizing needle of the atomizing nozzle extending into the inner wall of pipe I and protruding from the inner wall is 2-3 cm.

[0042] More preferably, the installation depth of the atomizing nozzle of the atomizing device on the pipe I is 3 cm, which is the length by which the atomizing needle of the atomizing nozzle extends into the inner wall of the pipe I and protrudes from the inner wall.

[0043] Preferably, when the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I is consistent, and the length of the atomizing needle of the atomizing nozzle extending into the inner wall of pipe I and protruding from the inner wall is consistent, the improved EVA hot melt adhesive production system adopts 2, 3 or 4 sets of atomizing devices. Each atomizing device includes 1 auxiliary agent solution storage tank, 1 metering pump, 1 valve FV and 1 atomizing nozzle. The atomizing nozzle of each atomizing device 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.

[0044] A further optimized and improved EVA hot melt adhesive production system employs four atomization devices;

[0045] More preferably, in the case of 4 sets of atomizing devices, the installation angle of the atomizing nozzle of each atomizing device is 45° with the angle between the center line of the atomizing nozzle body and the material flow direction in the pipe I, and the installation depth is 3cm with the length of the atomizing needle of the atomizing nozzle 16 extending into the pipe I and protruding from the inner wall of the pipe I.

[0046] Secondly, this application provides an improved EVA hot melt adhesive production system for use in EVA hot melt adhesives, employing the following technical solution:

[0047] The application of an improved EVA hot melt adhesive production system in EVA hot melt adhesives involves the following specific steps:

[0048] (1) Melt the raw materials used to prepare EVA hot melt adhesive in a stirring tank to obtain EVA hot melt adhesive melt material;

[0049] (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.

[0050] The additive is an organosilicon anti-sticking agent, preferably SH-3011, produced by Shanghai Chuyijia Organosilicon Materials Co., Ltd.

[0051] 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;

[0052] The inventors of this application used the additives within the specified dosage range to produce EVA hot melt adhesive particles, and after technical testing, the particles met the corresponding requirements for use in EVA hot melt adhesive particle products and had no impact on the performance of the EVA hot melt adhesive particle products.

[0053] This application uses hot melt adhesive for bookbinding as an example only, but does not limit the application of additives in other hot melt adhesive products;

[0054] (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 fed into an underwater pelletizer for underwater pelletizing.

[0055] The pumping speed of melt pump 2 is 26-28 r / min, and the conveying capacity is 20-25 kg / min;

[0056] 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;

[0057] (4) The EVA hot melt adhesive granules obtained after granulation in water in step (3) and the mixture of cooling water are fed into a dewatering machine for centrifugal separation and dewatering to achieve the separation of EVA hot melt adhesive granules and cooling water.

[0058] The separated cooling water is then recycled into a constant temperature water tank via a water circulation pump.

[0059] The centrifugal separation process of the above-mentioned dehydrator is controlled at a speed of 1200-1400 r / min;

[0060] 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;

[0061] (5) Open valves FV and FVI, start the metering pump, and the auxiliary aqueous solution in the auxiliary solution storage tank is sprayed into the pipeline 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. Spray the EVA hot melt adhesive particles after dehydration in step (4) to obtain the atomized EVA hot melt adhesive particles.

[0062] 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.

[0063] The flow rate of the additive solution entering the feed inlet of the atomizing nozzle in this application is only an example of a hot melt adhesive product for bookbinding. The specific flow rate of the additive solution should be adjusted according to the corresponding EVA hot melt adhesive product being prepared.

[0064] (6) The atomized EVA hot melt adhesive particles in step (5) are fed into a vibrating screen through pipe I for screening to remove particles with a diameter greater than 7 mm, particles with a diameter less than 5 mm, and fine powder. The qualified EVA hot melt adhesive particles screened out are dried by a blower drying system. The finished EVA hot melt adhesive particles are then fed into the EVA hot melt adhesive particle receiving tank 12 and bagged and stacked according to product specifications.

[0065] The diameter of qualified EVA hot melt adhesive granules is 5-7mm;

[0066] 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℃.

[0067] Using the above technical solution, the surface of the obtained EVA hot melt adhesive granules is uniformly coated with additives, which can effectively extend the time before the EVA hot melt adhesive granules begin to clump during subsequent storage. Furthermore, after the surface of the EVA hot melt adhesive granules is uniformly coated with additives, scaling in pipelines during production can be prevented, effectively reducing the production cost of scaling treatment and thus relatively improving production efficiency.

[0068] Beneficial technical effects of this application

[0069] This application discloses an improved EVA hot melt adhesive production system, which simply adds an atomizing device to the original EVA hot melt adhesive production system. The addition of a metering pump in the atomizing device enables precise metering of additives. The installation position and angle of the atomizing nozzle on the pipeline I between the dewatering machine and the vibrating screen, as well as the length of the atomizing needle of the atomizing nozzle extending into the pipeline I, are synergistically enhanced, allowing the additive mist to fully adhere to the surface of the EVA hot melt adhesive particles. This improves the technical problems of fouling in the pipeline I and poor anti-caking effect of EVA hot melt adhesive particles in the EVA hot melt adhesive production system. Compared to the previous EVA hot melt adhesive production system (without adding an atomizing device, and using the same additives and dosage to treat the EVA hot melt adhesive granules before bagging), the cleaning time for pipe I scale buildup was extended by 0.67-1.56 times, thus relatively reducing production costs and improving production efficiency; the time from bagging and stacking to the start of caking during EVA hot melt adhesive granule storage was extended by 3.00-5.56 times.

[0070] Furthermore, the improved EVA hot melt adhesive production system of this application can effectively extend the cleaning time required for pipe I to remove scale buildup and the time from bagging and stacking of EVA hot melt adhesive granules to the start of caking. Additionally, due to the use of a metering pump in the atomization device, automatic and accurate metering of additives can be achieved. Under the premise of the specified additive dosage, the quality of the EVA hot melt adhesive granules will not be affected by the addition of additives. Moreover, after a year and a half of product application by customers, the conclusion that the addition of additives does not affect the quality of the EVA hot melt adhesive granules has been verified.

[0071] Furthermore, the improved EVA hot melt adhesive production system of this application also has the advantages of simple operation and safe and reliable production process. Attached Figure Description

[0072] Figure 1 Example 1: A schematic diagram of the production process of an improved EVA hot melt adhesive production system. In the figure, 1 is a mixing 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 circulation pump, 8 is a dehydrator, 9 is a vibrating screen, 10 is a blower, 11 is a blower dryer, 12 is a receiving tank for EVA hot melt adhesive particles, 13 is an auxiliary agent solution storage tank, 14 is a metering pump, 15 is valve FV, 16 is an atomizing nozzle, 17 is a discharge valve FI, 18 is valve FII, 19 is valve FIII, 20 is valve FIV, 21 is valve FVI, and 22 is valve FVII.

[0073] Figure 2A schematic diagram of the production process of the EVA hot melt adhesive production system without atomization device in the comparative embodiment. In the figure, 1 is a mixing 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 circulation pump, 8 is a dewatering machine, 9 is a vibrating screen, 10 is a blower, 11 is a blower dryer, 12 is a receiving and storage 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.

[0074] Figure 3 A schematic diagram of the arrangement of the two atomizing nozzles 16 of the two atomizing devices in Example 2 on the cross section of pipe I;

[0075] Figure 4 A schematic diagram of the arrangement of the three atomizing nozzles 16 of the three atomizing devices in Example 3 on the cross section of pipe I;

[0076] Figure 5 A schematic diagram of the arrangement of the four atomizing nozzles 16 of the four atomizing devices in Example 4 on the cross section of pipe I. Detailed Implementation

[0077] The present application will be further described below with reference to specific embodiments and accompanying drawings, but this does not limit the present application.

[0078] The model and manufacturer information of the special equipment used in the embodiments of this application are as follows:

[0079] Equipment Name model Manufacturer information Stirring vessel HT250L Linyi Haixin Chemical Equipment Co., Ltd. melt pump MP-M-2500CC Zhengzhou Haike Melt Pump Co., Ltd. Filtration device HK-DP-2R-250 Zhengzhou Haike Melt Pump Co., Ltd. Extrusion die 012 Suzhou Demag Precision Tools Co., Ltd. underwater pelletizer KSFM-2000 Taizhou Kefei Rubber & Plastic Machinery Co., Ltd. dehydrator KSFM-2000 Taizhou Kefei Rubber & 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.

[0080] The method for determining the cleaning time required for the scale buildup in pipe I in various application embodiments of this application:

[0081] For both the improved EVA hot melt adhesive production system and the existing EVA hot melt adhesive production system, based on a production of 8 batches per day (each batch operates continuously for 2 hours), with an interval of 1.0-1.5 hours between each two adjacent batches, the time from when pipe I (the pipe between the dewatering machine and the vibrating screen) is put into use or when pipe I is cleaned for the last time, until a layer of particulate powder with a thickness of more than 0.5 cm accumulates on the inner wall of pipe I, is recorded as the cleaning time required for the scale buildup in pipe I.

[0082] Methods for determining the initial solidification time of hot melt adhesive granules for bookbinding obtained in various application embodiments of this application after bagging:

[0083] The time from the start of bagging 25kg bags of EVA hot melt adhesive granules (i.e., hot melt adhesive granules for bookbinding) until the formation of clumps larger than 5cm*5cm is recorded as the time when clumping begins after bagging. Example 1

[0084] An improved EVA hot melt adhesive production system includes a mixing tank, a discharge valve F1, a melt pump, a filter device, an extrusion die, an underwater pelletizer, a constant temperature water tank, a water circulation pump, a dewatering machine, a vibrating screen, and a blower drying system, and also includes an atomization device.

[0085] A schematic diagram of the production process of the improved EVA hot melt adhesive production system described above is shown below. Figure 1 As shown, Figure 1 In the diagram, 1 is a mixing 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 circulation pump, 8 is a dewatering machine, 9 is a vibrating screen, 10 is a blower, 11 is a blower dryer, 12 is a receiving tank for EVA hot melt adhesive particles, 13 is an auxiliary agent solution storage tank, 14 is a metering pump, 15 is valve FV, 16 is an atomizing nozzle, 17 is a discharge valve FI, 18 is valve FII, 19 is valve FIII, 20 is valve FIV, 21 is valve FVI, and 22 is valve VII.

[0086] The mixing vessel 1 is equipped with a feeding port and a bottom discharge port. The bottom discharge port of the mixing vessel 1 is connected to the melt pump 2, the filter device 3 and the extrusion die 4 in sequence through the discharge valve FI13.

[0087] The melt pump 2 has a pumping speed of 26-28 r / min and a delivery rate of 22 kg / min;

[0088] The filter pore diameter of the filter device 3 is 200 μm;

[0089] The outer ring of the extrusion die 4 is provided with 60 holes, each hole being a round hole with a diameter of 3mm ± 0.1mm; the extrusion die 4 is used to extrude the filtered EVA hot melt adhesive material through the extrusion die 4 and then to perform underwater pelletizing in the underwater pelletizer 5; by controlling the cutting speed of the underwater pelletizer 5, coarse EVA hot melt adhesive particles with the required particle size can be obtained;

[0090] The underwater pelletizer 5 is also equipped with a cooling water supply port and a material discharge port; the cutting speed of the underwater pelletizer 5 during operation is 1000 r / min;

[0091] The constant temperature water tank 6 is provided with an inlet and an outlet. The water supply pipe is connected to the inlet of the constant temperature water tank 6 through valve FII18. The outlet of the constant temperature water tank 6 is connected to the cooling water supply port of the underwater pelletizer 5 through a water circulation pump 7 to provide the cooling water required for underwater pelletizing by the underwater pelletizer 5.

[0092] The dewatering machine 8 is equipped with a material tangential inlet, a discharge outlet, and a drain outlet; the dewatering machine 8 is a high-speed centrifuge with a rotation speed of 1200 r / min;

[0093] The material outlet of the underwater pelletizer 5 is connected to the material tangential inlet of the dewatering machine 8 through a pipe, so as to discharge the EVA hot melt adhesive particles coarsely cut underwater in the underwater pelletizer 5 and water together into the dewatering machine 8.

[0094] The drain outlet on the dewatering machine 8 flows back into the constant temperature water tank 6 through valve FIII19, so as to realize the recycling and reuse of the cooling water used in the underwater pelletizer 5 in the production process, thereby saving water energy.

[0095] A branch pipeline is installed on the pipeline between valve FIII19 and dewatering machine 8. This branch pipeline goes through valve FIV20 to the factory's sewage collection point so that the waste liquid generated during the cleaning of the dewatering machine can be treated in the factory's unified waste treatment system.

[0096] The material outlet of the dewatering machine 8 is connected to the material inlet of the vibrating screen 9 via pipe I;

[0097] The aforementioned pipe I is divided into a horizontal section and a vertical section. The downward inclination of the horizontal section of pipe I, which exits from the material outlet of the dewatering machine 8, is 45°. The length of the horizontal section of pipe I is 1m. The outlet of the vertical section of pipe I is perpendicular to the material inlet of the vibrating screen 9.

[0098] The aforementioned blower drying system includes a blower dryer 11 and a blower 10. The blower dryer 11 is provided with a tangential feed inlet and a bottom discharge outlet.

[0099] The vibrating screen 9 also has a material outlet;

[0100] The material outlet of the vibrating screen 9 is connected to the tangential feed inlet of the blower dryer 11 via a pipe;

[0101] The receiving tank 12 for EVA hot melt adhesive particles is located at the bottom discharge port of the blower dryer 11 and is used to receive the EVA hot melt adhesive particles after they have been dried by the blower dryer 11.

[0102] The blower 10 is used to supply air to the blower dryer 11, with a pressure of 0.25 MPa and a temperature of 37-39°C.

[0103] A branch pipe is provided on the pipe between the material outlet of the vibrating screen 9 and the blower dryer 11, and near the material outlet of the vibrating screen 9. This branch pipe is connected to the blower 10, and the branch pipe is 0.2-0.3m away from the material outlet of the vibrating screen 9.

[0104] The atomizing device includes an auxiliary agent solution storage tank 13, a metering pump 14, a valve FV 15, and an atomizing nozzle 16;

[0105] The valve FV15 is a one-way valve used to prevent backflow of the auxiliary agent solution when the improved EVA hot melt adhesive production system is in operation.

[0106] The atomizing nozzle 16 is located at the midpoint of the upper half of the cross-section of the pipe I from the material outlet of the dewatering machine 8 to the material inlet of the vibrating screen 9, and 0.9m from the material outlet of the dewatering machine 8 (the midpoint of the upper half of the pipe is the middle position of the upper half of the cross-section of the pipe I 0.9m from the material outlet of the dewatering machine 8).

[0107] The connection between the atomizing nozzle 16 and the pipe I is achieved by connecting the external threaded connector on the atomizing nozzle 16 and the internal threaded connector welded to the pipe I through a threaded engagement.

[0108] The atomizing nozzle 16, model SK508, is manufactured by Dongguan Hengxin Spray Technology Co., Ltd. The inner diameter of the liquid spray nozzle of the atomizing nozzle body of the atomizing nozzle 16 is 3mm, and the inner diameter of the liquid inlet and air inlet of the atomizing nozzle body are both 10mm.

[0109] The ratio of the inner diameter of the liquid spray nozzle on the atomizing nozzle body of the atomizing nozzle 16 to the inner diameter of the pipe I is 3:100.

[0110] The installation angle of the atomizing nozzle 16 is 60°, with the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in the pipe I being 60°.

[0111] The installation depth of the atomizing nozzle 16 is such that the length of the atomizing needle of the atomizing nozzle 16 extending into the inner wall of the pipe I and protruding from the inner wall is 2.0 cm.

[0112] The auxiliary agent solution storage tank 13 in the atomizing device is equipped with a discharge pipe. The inlet of the discharge pipe is 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 of the atomizing nozzle 16 after passing through the metering pump 14 and valve FV15. The air inlet of the atomizing nozzle body of the atomizing nozzle 16 is connected to the compressed air input pipeline through valve FVI21.

[0113] The aforementioned valve FV15 is a one-way valve, installed 0.2-0.3m from the liquid inlet of the atomizing nozzle body of the atomizing nozzle 16;

[0114] The bottom of the auxiliary agent solution storage tank 13 is provided with a drain outlet, which is connected to the factory's wastewater collection point via valve FVII22 and pipeline, so that the waste liquid generated during the cleaning of the auxiliary agent solution storage tank can be treated in the factory's unified waste treatment system.

[0115] Comparative Examples

[0116] An EVA hot melt adhesive production system without an atomizing device differs from Example 1 in that it lacks an atomizing device; otherwise, it is identical to Example 1. The production process flow diagram of this EVA hot melt adhesive production system without an atomizing device is shown below. Figure 2 As shown, Figure 2 1 is a mixing 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 circulation pump, 8 is a dewatering machine, 9 is a vibrating screen, 10 is a blower, 11 is a blower dryer, 12 is a receiving and storage 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.

[0117] Examples 2-4

[0118] An improved EVA hot melt adhesive production system differs from Example 1 only in that:

[0119] The atomizing devices described in Examples 2-4 are 2 sets, 3 sets, and 4 sets, respectively; each atomizing device includes, as in Example 1, an auxiliary agent solution storage tank 13, a metering pump 14, a valve FV 15, and an atomizing nozzle 16;

[0120] Each atomizing nozzle 16 is located on the upper half of the cross-section of pipe I, 0.9m from the material outlet of dewatering machine 8, in the transverse section of pipe I (the upper half of the pipe is the cross-section of pipe I located 0.9m from the material outlet of dewatering machine 8, and above the horizontal centerline of pipe I parallel to the ground). The schematic diagrams of the arrangement of the atomizing nozzles of the 2, 3, and 4 atomizing devices in Examples 2-4 on the upper half of the cross-section of pipe I are shown below. Figure 3 , 4 As shown in Figure 5;

[0121] Figure 3 In accordance with Embodiment 2, when there are two atomizing devices, the two atomizing nozzles are arranged at an angle of 60° between the center lines of the main body of the atomizing nozzles on the upper half of the cross section of the pipe I, which is 0.9m away from the material outlet of the dewatering machine 8. The two atomizing nozzles divide the upper half of the cross section of the pipe I into three equal parts.

[0122] Figure 4In embodiment 3, when there are 3 atomizing devices, the atomizing nozzles are arranged at an angle of 45° between the center lines of the main body of each two adjacent atomizing nozzles on the upper half of the cross section of the pipe I, which is 0.9m away from the material outlet of the dewatering machine 8. The 3 atomizing nozzles divide the upper half of the cross section of the pipe I into 4 equal parts.

[0123] Figure 5 In embodiment 4, when there are 4 atomizing devices, they are arranged on the upper half of the cross section of the pipe I, which is 0.9m away from the material outlet of the dewatering machine, with the included angle of the center lines of the main body of each two adjacent atomizing nozzles being 60°. The 4 atomizing nozzles 16 divide the upper half of the cross section of the pipe I into 3 equal parts.

[0124] Examples 5-8

[0125] An improved EVA hot melt adhesive production system differs from Example 1 in that:

[0126] The installation angle of the atomizing nozzle 16 on the transverse section of pipe I is 30°, 45°, 80° and 90° respectively, depending on the angle between the center line of the atomizing nozzle body and the material flow direction in pipe I.

[0127] Examples 9-14

[0128] An improved EVA hot melt adhesive production system differs from Example 1 in that:

[0129] The lengths of the atomizing needle of the atomizing nozzle 16 that extend into and protrude from the inner wall of the pipe I are -0.5cm (referring to 0.5cm retracted into the inner wall), 0cm, 1cm, 3cm, 3.5cm, and 4cm, respectively. Example 15

[0130] An improved EVA hot melt adhesive production system differs from Example 1 in the following ways:

[0131] The atomizing device consists of 4 sets, and the atomizing nozzle 16 of each set is installed on the pipe I in the same position as in application embodiment 4.

[0132] The installation angle of each atomizing nozzle 16 on the transverse section of pipe I is such that the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in pipe I is 45°.

[0133] Each atomizing nozzle 16 has an atomizing needle that extends into the inner wall of pipe I and protrudes from the inner wall by a length of 3 cm.

[0134] Application Example 1

[0135] The production of hot melt adhesive for bookbinding is carried out using an improved EVA hot melt adhesive production system according to Example 1:

[0136] The raw materials used in the preparation of the hot melt adhesive for bookbinding, calculated by weight, have the following composition and content:

[0137] Amorphous α-olefin copolymer (Evonik Industries 508) 18 parts

[0138] Hydrogenated alicyclic hydrocarbon resin (ElxonMobil 5400) 21.5 parts

[0139] 22 parts of ethylene-methyl methacrylate copolymer (Sumitomo Chemical Co., Ltd. 5022)

[0140] 19 parts of pure monomer resin (SA85 from Pressure Sana Chemical Company).

[0141] #64 Paraffin (China Petroleum & Chemical Corporation) 18 portions

[0142] Titanium dioxide (R298 from Panzhihua Iron and Steel Group Co., Ltd.) 1 part

[0143] Antioxidant (antioxidant R298 from Panzhihua Iron and Steel Group Co., Ltd.) 0.5 parts;

[0144] The amount of additive (organosilicon anti-sticking agent, SH3011, Shanghai Chuyijia Organosilicon Materials Co., Ltd.) used in the preparation of hot melt adhesive for bookbinding is 0.07 parts, which means that the amount of additive is 0.07% of the total weight of the raw materials used in the preparation of the hot melt adhesive for bookbinding.

[0145] The hot melt adhesive used for bookbinding mentioned above is prepared by a method including the following steps:

[0146] (1) All raw materials for preparing hot melt adhesive for bookbinding are melted in a stirring vessel 1 to obtain the melt material of hot melt adhesive for bookbinding;

[0147] (2) The auxiliary agent is put into the auxiliary agent solution storage tank 13, then water is added, and after stirring evenly, an auxiliary agent aqueous solution with a mass percentage concentration of 25% is obtained;

[0148] (3) The hot melt adhesive for bookbinding obtained in step (1) is filtered by the filter device 3 and extruded by the extrusion die 4 under the power of the melt pump 2 and then enters the underwater pelletizer 5 for underwater pelletizing.

[0149] The pumping speed of melt pump 2 is 26-28 r / min, and the conveying rate of hot melt adhesive for bookbinding is 22 kg / min;

[0150] During pelletizing, the temperature of the cooling water in the constant temperature water tank 6 is controlled at 15℃. The cooling water in the constant temperature water tank 12 is pumped into the underwater pelletizer 5 through the water circulation pump 7. The cutting speed of the underwater pelletizer 5 during underwater cutting is 1000r / min.

[0151] (4) The EVA hot melt adhesive granules obtained after granulation in water in step (3) and the mixture of cooling water are fed into the dewatering machine 8 for centrifugal separation and dehydration to achieve the separation of EVA hot melt adhesive granules and cooling water.

[0152] The cooling water separated by the dehydrator 8 is returned to the constant temperature water tank 6 through valve FIII19 for recycling;

[0153] The centrifugal separation process of the aforementioned dehydrator 8 is controlled at a speed of 1200 r / min;

[0154] The flow rate of the above-mentioned coarse EVA hot melt adhesive granules exiting the material outlet of the dewatering machine 8 is 0.40 kg / s;

[0155] (5) Open valves FV15 and FVI21, turn on metering pump 14, and the auxiliary aqueous solution in auxiliary solution storage tank 13 is sprayed into pipeline I between dewatering machine 8 and vibrating screen 9 through valve FV15 and atomizing nozzle 16 under the action of metering pump 14. The auxiliary solution is sprayed onto the hot melt adhesive particles for bookbinding after dewatering by dewatering machine 8 in step (4) to obtain atomized hot melt adhesive particles for bookbinding.

[0156] During the above spraying process, the pressure of the compressed air input to the air inlet of the atomizing nozzle 16 is 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 16 is 18 mL / min.

[0157] (6) The coarse hot melt adhesive particles for bookbinding after atomization in step (5) enter the vibrating screen 9 through pipe I for screening to remove particles with a diameter greater than 7mm, particles with a diameter less than 5mm and fine powder. The qualified coarse hot melt adhesive particles for bookbinding are dried by the blower dryer 11. The finished hot melt adhesive particles for bookbinding are then put into the receiving tank 12 of EVA hot melt adhesive particles and bagged and stacked according to the specification of 25kg / bag.

[0158] The diameter of qualified hot melt adhesive granules for bookbinding is 5-7mm.

[0159] The air used in the blower dryer 11 is supplied by the blower 10, with a pressure of 0.25 MPa and a temperature of 38°C.

[0160] Application Comparative Examples

[0161] The EVA hot melt adhesive production system of the comparative embodiment is used to produce hot melt adhesive for bookbinding. The raw materials used in the preparation of the hot melt adhesive for bookbinding are the same as those in application embodiment 1 in terms of weight parts; the additives used in the preparation of the hot melt adhesive for bookbinding and their dosage are the same as those in application embodiment 1.

[0162] The specific steps for preparing the hot melt adhesive used for bookbinding are as follows:

[0163] (1) Following the same steps (1) as in Example 1, a hot melt adhesive for bookbinding is obtained;

[0164] (2) Following the same steps as in Example 1, an aqueous solution of the additive with a mass percentage concentration of 25% was obtained;

[0165] (3) Same as step (3) in Application Example 1;

[0166] (4) Same as step (4) in Application Example 1;

[0167] (5) After dehydration by the dehydrator 8 in step (4), the coarse hot melt adhesive particles for bookbinding enter the vibrating screen 9 through the pipe I for screening to remove particles with a diameter greater than 7 mm, particles with a diameter less than 5 mm, and fine powder. The qualified hot melt adhesive particles for bookbinding that are screened out are dried by the blower dryer 11 and then enter the receiving tank 12 of EVA hot melt adhesive particles. Then, the 25% mass percentage concentration of the auxiliary agent aqueous solution obtained in step (2) is added to the EVA hot melt adhesive particles and stirred evenly. Then, it is bagged and stacked according to the specification of 25 kg / bag.

[0168] The diameter of qualified hot melt adhesive granules for bookbinding is 5-7mm;

[0169] The air used in the blower dryer 11 is supplied by the blower 10, with a pressure of 0.25 MPa and a temperature of 38°C.

[0170] Application Examples 2-4

[0171] The production of hot melt adhesive for bookbinding is carried out using an improved EVA hot melt adhesive production system according to Examples 2-4:

[0172] The hot melt adhesive used for bookbinding is prepared using raw materials whose composition and content are the same as those in Application Example 1, calculated by weight percentage.

[0173] The preparation process of the hot melt adhesive for bookbinding described above is the same as that in Application Example 1, except for the following differences. The final qualified EVA hot melt adhesive particles are dried in a blower drying tower and then bagged and stacked in 25Kg / bags.

[0174] Example 2 uses two sets of atomizing devices. In each atomizing device, the compressed air input to the air inlet of the atomizing nozzle body of each atomizing nozzle 16 has a pressure of 0.4 MPa and a flow rate of 60 mL / min, and the auxiliary solution input to the liquid inlet of the atomizing nozzle body of the atomizing nozzle 16 has a flow rate of 9 mL / min.

[0175] The total flow rate of the additive solution entering the feed inlet of the two atomizing nozzles 16 of the above two atomizing devices is 18 mL / min.

[0176] Example 3 uses 3 sets of atomizing devices. In each atomizing device: the pressure of the compressed air input to the air inlet of the atomizing nozzle body of each atomizing nozzle 16 is 0.4 MPa and the flow rate is 60 mL / min. The flow rate of the additive solution input to the liquid inlet of the atomizing nozzle body of the atomizing nozzle 16 is 6 mL / min.

[0177] The total flow rate of the additive solution entering the feed inlet of the three atomizing nozzles 16 of the above three atomizing devices is 18 mL / min.

[0178] Example 4 uses 4 sets of atomizing devices. In each atomizing device: the compressed air input to the air inlet of the atomizing nozzle body 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 to the liquid inlet of the atomizing nozzle body of the atomizing nozzle 16 has a flow rate of 4.5 mL / min.

[0179] The total flow rate of the additive solution entering the feed inlet of the four atomizing nozzles 16 of the above four atomizing devices is 18 mL / min.

[0180] Application Examples 5-14

[0181] The production of hot melt adhesive for bookbinding is carried out using an improved EVA hot melt adhesive production system according to Examples 5-14:

[0182] The hot melt adhesive used for bookbinding is prepared using raw materials whose composition and content are the same as those in Application Example 1, calculated by weight percentage.

[0183] The preparation process of the hot melt adhesive for bookbinding described above is the same as that in Application Example 1. The final qualified EVA hot melt adhesive particles are dried in a blower drying tower and then bagged and stacked in 25Kg / bags.

[0184] Application Example 15

[0185] The production of hot melt adhesive for bookbinding is carried out using an improved EVA hot melt adhesive production system according to Example 15:

[0186] The hot melt adhesive used for bookbinding is prepared using raw materials whose composition and content are the same as those in Application Example 1, calculated by weight percentage.

[0187] In the preparation process of the hot melt adhesive for bookbinding, except for the following differences, all other steps are the same as those in Application Example 1. The qualified EVA hot melt adhesive particles are finally dried in a blower drying tower and then bagged and stacked in 25Kg / bag.

[0188] In Example 15, the four atomizing devices are as follows: the compressed air input to the air inlet of the atomizing nozzle body of the atomizing nozzle 16 has a pressure of 0.4 MPa and a flow rate of 60 mL / min; the auxiliary solution input to the liquid inlet of the atomizing nozzle body of the atomizing nozzle 16 has a flow rate of 4.5 mL / min.

[0189] The total flow rate of the additive solution entering the main body of the four atomizing nozzles of the four atomizing devices is 18 mL / min.

[0190] Based on a production rate of 8 batches per day (each batch operating continuously for 2 hours), with an interval of approximately 70 minutes between each adjacent batch, the following statistics were compiled regarding the time required to remove scale buildup in pipe I of the improved EVA hot melt adhesive production system with an atomizing device and the EVA hot melt adhesive production system without an atomizing device and without improvement, and the time from bagging of EVA hot melt adhesive particles to the start of caking:

[0191] Number of atomizing nozzles Installation angle of the atomizing nozzle (°) Installation depth of atomizing nozzle (cm) Time required to remove accumulated dirt (in days) Time from bagging to the onset of crusting (days) Application Example 1 1 60 2.0 150 120 Application Comparative Examples 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

[0192] The table above shows that, by comparing the data from Application Example 1 and Application Comparative Example 1, the improved EVA hot melt adhesive production system, due to the use of an atomizing device (using one atomizing device), results in a 0.67-fold increase in the cleaning time of the accumulated scale in pipe I compared to the original EVA hot melt adhesive production system (which did not use an atomizing device). At the same time, the time from bagging and stacking to the start of caking of the hot melt adhesive particles used for bookbinding is 3.00 times longer.

[0193] Comparing the data from Application Example 1, Application Comparative Example, and Application Examples 2-4, it can be seen that the improved EVA hot melt adhesive production system, when the atomizing needle of the atomizing nozzle 16 extends into and protrudes from the inner wall of pipe I to a consistent length, and the angle between the center line of the atomizing nozzle body of the atomizing device 16 and the material flow direction in pipe I is consistent, is significantly improved compared to the original EVA hot melt adhesive production system without improvement, due to the use of an atomizing device (Examples 1 and 2-4 use 1, 2, 3, or 4 sets of atomizing devices, respectively). (Without using an atomizing device) (Comparative Example), the cleaning time of scale buildup in pipe I and the time from bagging and stacking of hot melt adhesive particles for bookbinding to the start of caking were significantly longer. In particular, when using 2, 3, and 4 sets of atomizing devices, compared to using 1 set of atomizing devices, the cleaning time of scale buildup in pipe I was extended by 20.0%, 33.3%, and 40.0%, respectively; the time from bagging and stacking of hot melt adhesive particles for bookbinding to the start of caking was extended by 25.0%, 50%, and 53.3%, respectively.

[0194] In particular, in Application Example 4, which uses 4 sets of atomizing devices, the cleaning time of the scale buildup in Pipe I and the time from when the hot melt adhesive particles used for bookbinding start to clump together are both significantly longer.

[0195] Comparing the data from Application Examples 1 and 5-8 in the table above, it can be seen that in the improved EVA hot melt adhesive production system using one atomizing device, when the atomizing needle of the atomizing nozzle 16 extends into the pipe I and protrudes from the inner wall of the pipe I to the same length, the installation angle of the atomizing nozzle 16 on the pipe I is 45-80°, according to the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in the pipe I. The time required to clean the scale buildup in the pipe I of the improved EVA hot melt adhesive production system and the time from bagging and stacking to the start of caking are both relatively long.

[0196] In particular, in application embodiment 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 pipe I is 45°, the time required to clean the scale buildup in the pipe I and the time from the start of bagging and stacking to the start of caking are relatively longer.

[0197] Comparing the data from Application Examples 1 and 9-14 in the table above, it can be seen that in the improved EVA hot melt adhesive production system using one atomizing device, when the angle between the center line of the atomizing nozzle body of the atomizing nozzle 16 and the material flow direction in the pipe I is consistent, the length of the atomizing needle of the atomizing nozzle 16 in the atomizing device extending into the pipe I and protruding from the inner wall of the pipe I is 2.0-3.0cm. The time required to clean the scale buildup in the pipe I of the improved EVA hot melt adhesive production system and the time from bagging and stacking to the start of caking are relatively long.

[0198] In particular, in Application Example 12, when the atomizing needle of the atomizing nozzle 16 in the atomizing device extends into the pipe I and protrudes from the inner wall of the pipe I for a length of 3.0 cm, the cleaning time of the accumulated dirt in the pipe I of the improved EVA hot melt adhesive production system is relatively longer, as is the time from bagging and stacking to the start of caking.

[0199] Comparing the data from Application Example 15 and Application Comparison Example in the table above, it can be seen that the improved EVA hot melt adhesive production system using 4 sets of atomizing devices, with the atomizing nozzle 16 of each atomizing device having an angle of 45° between the center line of the atomizing nozzle body and the material flow direction in pipe I, and the atomizing needle of the atomizing nozzle 16 extending into pipe I and protruding 3cm from the inner wall of pipe I, can relatively extend the cleaning time of the scale buildup in pipe I by 1.56 times compared to the EVA hot melt adhesive production system without atomizing devices; and relatively extend the time from bagging and stacking to the start of caking in the storage process of hot melt adhesive granules for bookbinding by 5.56 times.

[0200] In summary, the improved EVA hot melt adhesive production system of this application addresses the pipe scaling problem of the original EVA hot melt adhesive production system, thereby reducing production costs and increasing production efficiency. It also solves the technical problem of poor anti-caking effect of EVA hot melt adhesive particles produced by the original EVA hot melt adhesive production system, effectively improving the anti-caking effect of EVA hot melt adhesive particles.

[0201] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

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; characterized in that, 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; The auxiliary agent solution storage tank is used to store the auxiliary agent aqueous solution. The mass percentage concentration of the auxiliary agent aqueous solution is 25-30%. The auxiliary agent in the auxiliary agent aqueous solution is an organosilicon anti-sticking agent. The amount of auxiliary agent is 0.04-0.10% of the total weight of the raw materials used in the preparation of EVA hot melt adhesive.

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. The 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 in the preparation of EVA hot melt adhesive are placed into an 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 is an organosilicon anti-sticking agent, namely SH-3011, produced 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 fed into an underwater pelletizer for underwater pelletizing. The speed of the melt pump is 26-28 r / min and the conveying rate is 20-25 kg / min. During the pelletizing process, the temperature of the water in the constant temperature water tank is controlled at 15-25℃ and the speed of the underwater pelletizer is 1000-1200 r / 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 dehydration; The centrifugal separation process of the above-mentioned dewatering machine is controlled at a speed of 1200-1400 r / min; The flow rate of the above-mentioned EVA hot melt adhesive granules when they come out of the material outlet of the dewatering machine is 0.35-0.45 kg / s; (5) Open valves FV and FVI, and start the metering pump. The additive solution in the additive solution storage tank is sprayed into the pipeline 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 crude EVA hot melt adhesive particles after dehydration in step (4) are sprayed to obtain atomized crude EVA hot melt adhesive particles. 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. The flow rate of the additive solution entering 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 EVA hot melt adhesive particle receiving tank and bagged and stacked according to the product specifications. The blower dryer in the blower drying system is supplied with air by a blower. The blower supply air pressure is 0.2-0.3Mpa and the temperature is 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 conveying rate is 22 kg / min; the temperature of the water in the constant temperature water tank is controlled at 15℃ during the pelletizing process and the speed of the underwater pelletizer is 1000 r / 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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