Method for sizing polyvinyl acetate glue in the continuous production of shaving board

Abstract

This invention relates to the technical field of adhesive application in particleboard production, specifically a method for applying polyvinyl acetate (PVC) adhesive in continuous particleboard production. The application steps are as follows: Step 1: Mix the PVC adhesive stock solution with water to prepare a PVC adhesive solution with a mass percentage concentration of 12-13%; Step 2: Continuously stir the prepared PVC adhesive solution at a low speed; Step 3: Pump the prepared PVC adhesive solution through a static mixer in the adhesive application system and mix it evenly with process water, then apply it to the material in the surface mixing machine through a two-fluid nozzle. The two-fluid nozzle is supplied with air from an air distribution unit, and each branch outlet of the air distribution unit is equipped with a separate air pressure regulating valve. This method for applying PVC adhesive in continuous particleboard production improves atomization and uniformity of adhesive application, and reduces the amount of PVC adhesive required.

Description

Technical Field

[0001] This invention relates to the technical field of adhesive application in particleboard production, specifically a method for applying polyvinyl acetate adhesive in the continuous production of particleboard. Background Technology

[0002] Traditional particleboard often uses adhesives with high formaldehyde content, which have poor environmental performance. Currently, isocyanate adhesives are commonly used, but isocyanate adhesives tend to stick to steel strips when applied to the surface of particleboard, resulting in a high failure rate. Polyvinyl acetate emulsion is a single-component emulsion with advantages such as low price, easy production, high bonding strength, and non-toxicity. Due to its wide compatibility with other resins, excellent adhesion, lower bonding pressure, colorless and transparent adhesive film that does not stain the material surface, and flexibility, using polyvinyl acetate adhesive to replace part of the isocyanate adhesive in particleboard can reduce the failure rate and improve production efficiency. Therefore, more and more particleboard manufacturers are using polyvinyl acetate adhesive in their particleboard production.

[0003] Application research has revealed that the modified polyvinyl acetate adhesive has a high viscosity, resulting in poor flowability and atomization when applied directly using a pump sprayer. This leads to uneven application and excessive application amounts during production. Therefore, it is necessary to design an application method that provides good atomization, uniform application and mixing, and reduces the amount of polyvinyl acetate adhesive required. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a method for applying polyvinyl acetate adhesive in continuous particleboard production. This method can improve the atomization effect and the uniformity of adhesive application, and can reduce the amount of polyvinyl acetate adhesive applied.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for applying polyvinyl acetate adhesive in continuous particleboard production includes the following steps: Step 1: Mix the original polyvinyl acetate adhesive liquid with water to prepare a polyvinyl acetate adhesive solution with a mass percentage concentration of 12-13%.

[0006] Step 2: Continuously stir the prepared polyvinyl acetate adhesive solution at a low speed. The stirring speed should not exceed 70 rpm.

[0007] Step 3: The prepared polyvinyl acetate adhesive solution is pumped through the static mixer of the adhesive application system and mixed evenly with the process water. Then, it is applied to the material in the surface adhesive mixer through a two-fluid nozzle. The two-fluid nozzle is supplied with air from the air distribution package, and each branch outlet of the air distribution package is equipped with a separate air pressure regulating valve.

[0008] A further preferred embodiment is that the mass ratio of the polyvinyl acetate adhesive solution to the process water is 7:(11-12), the process water is clean water, and the proportion of process water added will be slightly adjusted according to the moisture content of the wood shavings used in the paving.

[0009] A further preferred embodiment: The adhesive application system includes an inlet cylinder, a mixing pipe, a T-shaped distribution pipe, and a gas distribution manifold. One end of the inlet cylinder is connected to one end of the mixing pipe, and the other end of the inlet cylinder is provided with multiple adhesive inlet pipes. Multiple process water inlet pipes are provided on the inlet cylinder, and the outlet of the process water inlet pipe is inclined towards the mixing pipe. The inclined arrangement of the process water inlet pipe can concentrate and mix the process water and the adhesive introduced from the adhesive inlet pipe in the inlet cylinder before entering the mixing pipe for further mixing. The other end of the mixing pipe is connected to the middle pipe of the T-shaped distribution pipe. For easy disassembly and assembly, the liquid inlet cylinder and the T-shaped distribution pipe are connected to the mixing pipe by flanges. A spiral blade is fixedly installed inside the mixing pipe, and the spiral blade is arranged along the length of the mixing pipe. The T-shaped distribution pipe is equipped with multiple glue outlet pipes. Each glue outlet pipe is connected to a two-fluid nozzle through a glue delivery pipe. The air distribution manifold is equipped with multiple branch outlet pipes. The air distribution manifold is connected to an air compressor. A pressure regulating valve is installed on the branch outlet pipe. The pressure regulating valve precisely regulates the nozzle air pressure to ensure stable and continuous air pressure and maintain the optimal atomization effect of the glue application nozzle. Each branch outlet pipe is connected to a two-fluid nozzle through a gas delivery pipe. The two-fluid nozzle is installed inside the surface glue mixer. The two-fluid nozzle for applying polyvinyl acetate adhesive solution is connected to the air distribution unit, and each branch outlet is equipped with an individual air pressure regulating valve to precisely adjust the nozzle air pressure, ensuring stable and continuous air pressure, maintaining the optimal atomization effect of the nozzle, and making the application and mixing of polyvinyl acetate adhesive solution more uniform.

[0010] A further preferred embodiment includes an adhesive inlet regulating valve installed on the adhesive inlet pipe. This regulating valve not only adjusts the adhesive flow rate but also facilitates maintenance of all pipelines. When a pipeline requires maintenance, closing the regulating valve does not affect the normal operation of other pipelines and prevents leakage due to the inability to seal the affected pipeline.

[0011] A further preferred embodiment: the adhesive inlet pipe is connected to the mixer via a pump pipe, and the pump pipe is equipped with an adhesive pump and a liquid flow meter. The mixer can continuously maintain low-speed stirring of the prepared polyvinyl acetate adhesive solution to ensure the uniformity and stability of the prepared solution; the liquid flow meter independently meters and applies the prepared polyvinyl acetate adhesive solution.

[0012] A further preferred embodiment includes an inlet regulating valve installed on the process water inlet pipe. This inlet regulating valve not only adjusts the water flow rate of each pipeline but also facilitates maintenance of all pipelines. When a pipeline requires maintenance, closing the inlet regulating valve does not affect the normal operation of other pipelines and prevents leakage due to the inability to close the valve.

[0013] A further preferred embodiment: The process water inlet pipe is connected to the water tank via a pump pipe, which is equipped with a water pump and a liquid flow meter. The metered polyvinyl acetate adhesive solution is first mixed evenly with the process water in a static mixer, and then applied to the material in the surface mixing machine through a two-fluid nozzle. The polyvinyl acetate adhesive solution is mixed evenly with the process water (ordinary clean water) in the static mixer, undergoing a second dilution. The total volume of the diluted solution is larger, and the number of two-fluid nozzles used increases from 2-3 before mixing in the static mixer to 5-6 after mixing, effectively doubling the number of nozzles. This doubles the application area of ​​the polyvinyl acetate adhesive solution, resulting in a larger and more comprehensive application and mixing of the adhesive material.

[0014] A further preferred embodiment includes a dispensing regulating valve installed on the dispensing pipe. This valve facilitates adjustment of the dispensing volume of each dispensing pipe, and combined with the adjustment of the air distribution manifold, ensures more uniform dispensing and mixing of the adhesive.

[0015] The application method of this polyvinyl acetate adhesive in continuous particleboard production has the following advantages: 1. This application method involves first preparing a polyvinyl acetate (PVC) adhesive solution from the original PVC adhesive liquid. Then, the metered PVC adhesive solution is mixed evenly with process water using a static mixer before being applied to the material in the surface mixing machine via a two-fluid nozzle. The PVC adhesive solution undergoes a second dilution after being evenly mixed with process water in the static mixer, resulting in a larger total volume of solution. The number of two-fluid nozzles used increases from 2-3 before mixing to 5-6 after mixing, effectively doubling the number of nozzles. This doubles the application area of ​​the PVC adhesive solution, resulting in a larger and more comprehensive application area, more uniform mixing, better atomization, and more even application.

[0016] 2. The two-fluid nozzle for applying polyvinyl acetate adhesive solution is connected to an air distribution unit, and each branch outlet is equipped with an individual air pressure regulating valve to precisely adjust the nozzle air pressure, ensuring stable and continuous air pressure and maintaining optimal atomization effect. This results in more uniform mixing of the polyvinyl acetate adhesive solution. The consumption of polyvinyl acetate adhesive has been reduced from 4 kg / m³ to approximately 1.8 kg / m³ after technical optimization, achieving the goal of reducing polyvinyl acetate adhesive consumption and saving costs.

[0017] 3. The glue inlet pipe of the glue application system is connected to the mixer through the glue pump pipe. The glue pump pipe is equipped with a glue pump and a liquid flow meter. The mixer can continuously stir the prepared polyvinyl acetate glue solution at a low speed to ensure the uniformity and stability of the prepared solution. The liquid flow meter independently meter and apply the prepared polyvinyl acetate glue solution. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the connection relationship using the adhesive application system; Figure 2 This is a schematic diagram of the planar structure of a static mixer; Figure 3 This is a three-dimensional structural diagram of a static mixer; The names corresponding to the serial numbers in the figure are: 1. Mixer; 2. Adhesive pump; 3. Liquid flow meter one; 4. Glue pump hose; 5. Water pump; 6. Water tank; 7. Water pump hose; 8. Liquid flow meter two; 9. Adhesive inlet pipe; 10. Liquid inlet cylinder; 11. Process water inlet pipe; 12. Mixing pipe; 13. Spiral vane; 14. T-type distribution pipe; 15. Glue outlet regulating valve; 16. Glue outlet pipe; 17. Two-fluid nozzle; 18. Air pressure regulating valve; 19. Air distribution manifold; 20. Branch outlet pipe; 21. Air supply pipe; 22. Glue supply pipe; 23. Glue inlet regulating valve; 24. Water inlet regulating valve. Detailed Implementation

[0019] To provide a more detailed description of the present invention, the following description is provided in conjunction with embodiments and accompanying drawings.

[0020] Example 1

[0021] The following steps can be used to apply polyvinyl acetate adhesive in the continuous production of particleboard: Step 1: Mix the original polyvinyl acetate adhesive liquid with water to prepare a polyvinyl acetate adhesive solution with a mass percentage concentration of 12-13%.

[0022] Step 2: Continuously stir the prepared polyvinyl acetate adhesive solution at a low speed.

[0023] Step 3: The prepared polyvinyl acetate adhesive solution is pumped through the static mixer of the sizing system and mixed evenly with process water. Then, it is applied to the material in the surface mixing machine through a two-fluid nozzle. Air is supplied to the two-fluid nozzle from an air distribution unit, and each branch outlet of the air distribution unit is equipped with a separate air pressure regulating valve. The mass ratio of the polyvinyl acetate adhesive solution to process water is 7:(11-12). The process water is clean water, and the proportion of process water added will be slightly adjusted according to the moisture content of the wood shavings used in the paving.

[0024] like Figure 1-3As shown, the adhesive application system includes an inlet cylinder 10, a mixing pipe 12, a T-shaped distribution pipe 14, and a gas distributor 19. One end of the inlet cylinder 10 is connected to one end of the mixing pipe 12, and the other end of the inlet cylinder 10 is provided with multiple adhesive inlet pipes 9. Multiple process water inlet pipes 11 are also provided on the inlet cylinder 10, with the outlets of the process water inlet pipes 11 inclined towards the mixing pipe 12. The other end of the mixing pipe 12 is connected to the middle pipe of the T-shaped distribution pipe 14. For easy assembly and disassembly, the inlet cylinder 10 and the T-shaped distribution pipe 14 are connected to the mixing pipe 12 using a method... The mixing pipe 12 is connected to the flange, and a spiral blade 13 is fixedly installed inside the mixing pipe 12. The spiral blade 13 is arranged along the length of the mixing pipe 12. The T-shaped distribution pipe 14 is provided with multiple glue outlet pipes 16. Each glue outlet pipe 16 is connected to a two-fluid nozzle 17 through a glue delivery pipe 22. The air distribution manifold 19 is provided with multiple branch outlet pipes 20. The air distribution manifold 19 is connected to an air compressor. The branch outlet pipes 20 are equipped with air pressure regulating valves 18. Each branch outlet pipe 20 is connected to a two-fluid nozzle 17 through an air delivery pipe 21. The two-fluid nozzle for applying polyvinyl acetate adhesive solution is connected to the air distribution manifold and is equipped with an individual air pressure regulating valve at each branch outlet to precisely adjust the nozzle air pressure, ensure stable and continuous air pressure, maintain the optimal atomization effect of the application nozzle, and make the application and mixing of polyvinyl acetate adhesive solution more uniform.

[0025] The adhesive inlet pipe 9 is equipped with an adhesive inlet regulating valve 23. The adhesive inlet pipe 9 is connected to the mixer 1 via a pump pipe 4, which is equipped with a suction pump 2 and a liquid flow meter 3. The process water inlet pipe 11 is equipped with a water inlet regulating valve 24. The process water inlet pipe 11 is connected to the water tank 6 via a pump pipe 7, which is equipped with a water pump 5 and a liquid flow meter 8. The metered polyvinyl acetate adhesive solution is first mixed evenly with process water in a static mixer, and then applied to the material in the surface mixing machine through a two-fluid nozzle. After the polyvinyl acetate adhesive solution is evenly mixed with process water in the static mixer, it undergoes a second dilution. The total volume of the diluted solution is larger, and the number of two-fluid nozzles used increases from 2-3 before mixing in the static mixer to 5-6 after mixing, effectively doubling the number of nozzles. This doubles the application area of ​​the polyvinyl acetate adhesive solution, resulting in a larger and more comprehensive adhesive material area and more uniform application and mixing.

[0026] The working process of this adhesive application system is as follows: First, according to the set ratio, the polyvinyl acetate adhesive raw liquid and water are added to the mixer 1 and stirred to form a polyvinyl acetate adhesive solution; the liquid flow meter 1 3, the glue inlet regulating valve 23, the liquid flow meter 2 8 and the water inlet regulating valve 24 are adjusted, the glue pump pipe 4 and the water pump 5 are started, and the prepared polyvinyl acetate adhesive solution and process water are quantitatively pumped into the liquid inlet cylinder 10, then through the mixing pipe 12, and due to the setting of the spiral blade 13, the polyvinyl acetate adhesive solution and process water are mixed in the mixing pipe 12 and then enter the T-type distribution pipe 14. Finally, it is transported from the glue outlet pipe 16 to the glue delivery pipe 22 to the two-fluid nozzle 17, and atomized and sprayed out from the two-fluid nozzle 17. According to the atomization effect, the glue outlet regulating valve 15 and the air pressure regulating valve 18 are adjusted so that the two-fluid nozzle 17 achieves the best atomization effect.

[0027] During the trial production process, it was found that after the polyvinyl acetate adhesive solution was uniformly mixed with process water in a static mixer and then diluted twice, the total volume of the diluted solution was larger. The number of two-fluid nozzles used increased from 2-3 before mixing in the static mixer to 5-6 after mixing, effectively doubling the number of nozzles. This doubled the application area of ​​the polyvinyl acetate adhesive solution, resulting in a larger and more comprehensive application area and more uniform mixing. Without affecting product performance, the consumption of polyvinyl acetate adhesive was reduced from 4 kg / m³ to approximately 1.8 kg / m³ after technical optimization, achieving the goal of reducing the consumption of polyvinyl acetate adhesive and saving costs.

[0028] The above description is not intended to limit the present invention, nor is the present invention limited to the above examples. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should be protected by the present invention.

Claims

1. A method for applying polyvinyl acetate adhesive in continuous particleboard production, characterized in that, Includes the following steps: Step 1: Mix the original polyvinyl acetate adhesive solution with water to prepare a polyvinyl acetate adhesive solution with a mass percentage concentration of 12-13%. Step 2: Continuously stir the prepared polyvinyl acetate adhesive solution at a low speed; Step 3: The prepared polyvinyl acetate adhesive solution is pumped through the static mixer of the adhesive application system and mixed evenly with the process water. Then, it is applied to the material in the surface adhesive mixer through a two-fluid nozzle. The two-fluid nozzle is supplied with air from the air distribution package, and each branch outlet of the air distribution package is equipped with a separate air pressure regulating valve.

2. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 1, characterized in that, The mass ratio of the polyvinyl acetate adhesive solution to process water is 7:(11-12).

3. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 1, characterized in that, The adhesive application system includes an inlet cylinder (10), a mixing pipe (12), a T-shaped distribution pipe (14), and a gas distribution manifold (19). One end of the inlet cylinder (10) is connected to one end of the mixing pipe (12), and the other end of the inlet cylinder (10) is provided with multiple adhesive inlet pipes (9). Multiple process water inlet pipes (11) are provided on the inlet cylinder (10). The other end of the mixing pipe (12) is connected to the middle pipe of the T-shaped distribution pipe (14). A fixed container is installed inside the mixing pipe (12). The spiral blade (13) and the T-shaped distribution pipe (14) are provided with multiple glue outlet pipes (16). Each glue outlet pipe (16) is connected to a two-fluid nozzle (17) through a glue supply pipe (22). The air distribution manifold (19) is provided with multiple branch outlet pipes (20). Each branch outlet pipe (20) is equipped with a pressure regulating valve (18). Each branch outlet pipe (20) is connected to a two-fluid nozzle (17) through an air supply pipe (21).

4. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 3, characterized in that, The adhesive inlet pipe (9) is equipped with an adhesive inlet regulating valve (23).

5. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 3 or 4, characterized in that, The glue inlet pipe (9) is connected to the mixer (1) through the glue pump pipe (4), and the glue pump (2) and the liquid flow meter (3) are installed on the glue pump pipe (4).

6. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 3, characterized in that, The process water inlet pipe (11) is equipped with an inlet regulating valve (24).

7. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 3 or 6, characterized in that, The process water inlet pipe (11) is connected to the water tank (6) through the pump pipe (7), and the pump pipe (7) is equipped with a water pump (5) and a liquid flow meter (8).

8. The method for applying polyvinyl acetate adhesive in continuous particleboard production according to claim 3, characterized in that, The dispensing pipe (16) is equipped with a dispensing regulating valve (15).

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