Preparation process of urea-formaldehyde glue for producing plywood

Abstract

The invention relates to the technical field of plywood processing, and particularly discloses a preparation process of urea-formaldehyde glue for plywood production, which comprises the following steps: raw material preparation, reaction device preparation, feeding, urea addition, condensation polymerization, acidification, cooling and adjustment, and filtration. According to the preparation technology of the urea-formaldehyde glue for producing the plywood, the preparation equipment of the urea-formaldehyde glue for producing the plywood is provided. The preparation equipment comprises a main console, a reaction mechanism, a solid preprocessing mechanism, a temperature control system, a storage tank, a first conveying pump, a base frame, a second conveying pump and a filtering module. According to the preparation process of the urea-formaldehyde glue for producing the plywood, by optimizing the mixing and adding processes, the reaction time can be shortened, the production efficiency can be improved, the bonding strength and stability of the urea-formaldehyde glue can be improved through uniform mixing and efficient reaction, and the quality of a final product is enhanced; and the mixture is added below the liquid level, so that side reactions such as hydrolysis of urea can be reduced, and the purity and performance of the product are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of plywood processing, in particular to a preparation process of urea-formaldehyde glue for producing plywood. Background Art

[0002] Urea-Formaldehyde Resin (UF Resin for short) is a synthetic resin adhesive made by polycondensation of urea and formaldehyde under the action of alkaline or acidic catalysts. Since it was invented in the early 20th century, this adhesive has become one of the most commonly used adhesives in the wood processing industry. The preparation of urea-formaldehyde adhesive is based on the polycondensation reaction between urea and formaldehyde. Under alkaline conditions, urea and formaldehyde first form monomethylol urea, and then further polycondense under acidic conditions to form a high molecular weight resin. Urea-formaldehyde adhesive is widely used in the wood processing industry, such as the production of plywood, particleboard, fiberboard, and furniture manufacturing. It is also used for bonding other materials, such as paper, fabric and foam plastics. In the prior art, during the processing of urea-formaldehyde glue, solid urea and formaldehyde solution are reacted by direct mixing, which leads to uneven mixing, affecting the uniformity of the reaction and the quality of the final product. In addition, the existing stirring and mixing method reduces the contact area between urea and formaldehyde solution, resulting in a slow reaction speed, which affects the efficiency of large-scale production and processing. Summary of the invention

[0003] The object of the present invention is to provide a process for preparing urea-formaldehyde glue for producing plywood, so as to at least solve the technical problems mentioned in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a process for preparing urea-formaldehyde glue for producing plywood, characterized in that it comprises the following steps: Step 1: Raw material preparation: prepare the following raw materials: urea: purity ≥99%, formaldehyde: concentration 37%, alkaline catalyst: ammonia water, acidic catalyst: hydrochloric acid; Step 2: Prepare the reaction device: clean the reaction device to ensure that there are no impurities, and preheat the heating system to the set temperature; Step 3: Adding materials: Add formaldehyde solution into the reaction device according to the molar ratio of formaldehyde to urea of ​​1.5:1 to 2.0:1, add an appropriate amount of alkaline catalyst, and adjust the pH value to 7.5-9.0; Step 4: Urea addition: pre-processing solid urea so that it is quantitatively mixed with the formaldehyde solution to form a mixture, and adding the mixture to a position below the liquid level of the formaldehyde solution; Step 5: Polycondensation reaction: polycondensation reaction is carried out at a reaction temperature of 80°C-100°C, and the reaction time is usually 1-3 hours, until the desired viscosity is reached; Step 6: Acidification: After the reaction reaches a certain extent, add an acid catalyst and adjust the pH value to 4.5-5.5 to promote resin curing; Step 7: Cooling and adjustment: After the reaction is completed, cool the resin to 40℃-50℃, and adjust the viscosity and solid content as needed. The viscosity is usually between 500-2000cps and the solid content is 50%-70%; Step 8: Filtration: Filter the resin to remove possible impurities.

[0005] Preferably, the reaction device includes: a main console, a reaction mechanism, a solid pre-processing mechanism, a temperature control system, a storage box, a first delivery pump, a base frame, a second delivery pump and a filter module; the reaction mechanism is arranged on the rear side of the main console; the solid pre-processing mechanism is arranged on the right side of the reaction mechanism; the temperature control system is arranged on the right side of the main console, and the temperature control system and the main console are electrically connected; the number of the storage boxes is two, and the two storage boxes are adjacently arranged on the left side of the main console; the first delivery pump is arranged on the right side of the storage box, the first delivery pump is connected to the two storage boxes through pipelines, and the first delivery pump is electrically connected to the main console; the base frame is installed at the rear bottom of the reaction mechanism; the second delivery pump is installed on the top front side of the base frame, and the second delivery pump is electrically connected to the main console; the filter module is installed on the top rear side of the base frame, the second delivery pump is connected to the filter module through pipelines, and the filter module is electrically connected to the main console.

[0006] Preferably, the reaction mechanism comprises: a base shell, a bottom liner, a discharge pipe, an outer shell, a temperature control pipe joint, a maintenance platform, a top liner, a pressure relief valve, a liquid inlet valve pipe and a mixing component; the base shell is fixedly installed at the rear bottom of the main console; the bottom liner is arranged on the inner top of the base shell; the discharge pipe is arranged in the middle of the bottom end of the discharge pipe, one end of the discharge pipe is connected to the bottom of the inner cavity of the bottom liner, and the other end of the discharge pipe is connected to the second delivery pump; the outer shell is arranged on the outer side of the top end of the base shell in the up and down direction; the temperature control pipe joint is arranged Installed at the front opening of the outer shell, the temperature control pipe joint and the temperature control system are connected through a pipeline; the maintenance platform is arranged on the outside of the base shell and the outer shell; the top inner tank is installed at the top of the bottom inner tank, the bottom of the inner cavity of the top inner tank is communicated with the inner cavity of the bottom inner tank, and the top of the top inner tank extends out of the top of the outer shell; the pressure relief valve is installed at the rear opening of the top of the top inner tank, and the pressure relief valve is electrically connected to the main console; the liquid inlet valve pipe is installed at the top opening of the top inner tank; the mixing component is arranged in the inner cavity of the top inner tank.

[0007] Preferably, the mixing component comprises: a hollow rotating shaft, a nozzle, a locking frame, a stirring rod, a through-hole tube, a shell, a first motor and a gear set; the hollow rotating shaft is rotatably connected to the top opening of the inner cavity of the top liner through a bearing in the up and down directions; the number of the nozzles is three, and the three nozzles are arranged at intervals from bottom to top on the bottom of the outer wall of the hollow rotating shaft; the number of the locking frames is several, and several locking frames are installed at intervals from top to bottom on the outer wall of the hollow rotating shaft; the number of the stirring rods is two groups, the number of the stirring rods in each group is several, and the two groups of stirring rods are installed at intervals on the outside of several locking frames, and the left and right stirring rods are arranged at intervals. The mixing rod is staggered; the through-hole tube is inserted into the bottom of the inner cavity of the hollow rotating shaft along the up-down direction; the outer shell is installed on the top of the top inner tank, and the top of the hollow rotating shaft extends into the bottom of the inner cavity of the outer shell; the first motor is installed on the top of the outer shell, and the rotating end of the first motor extends into the top of the inner cavity of the outer shell, and the first motor is electrically connected to the main console; the number of the gear sets is two, and the two gear sets are respectively arranged on the upper and lower sides of the inner cavity of the outer shell, and the transmission gears in the two gear sets are connected by a linkage shaft, and the driving gears in the two gear sets are respectively connected to the rotating end of the first motor and the top of the outer wall of the hollow rotating shaft.

[0008] Preferably, the mixing component also includes: a first rotating shaft, a connecting gear, a second rotating shaft, a cam, a bevel gear set, a connecting plate, a spring, a roller seat and a telescopic joint; the first rotating shaft is rotatably connected to the top end of the inner cavity of the shell through a bearing; the connecting gear key is connected to the top of the outer wall of the first rotating shaft, and the connecting gear is meshed with the front side of the driving gear of the top gear set; the second rotating shaft is rotatably connected to the front side of the outer wall of the shell through a bearing in the front-to-back direction; the cam is arranged at the rear end of the axis of the second rotating shaft; one end of the bevel gear set is keyed to the bottom end of the first rotating shaft, and the other end of the bevel gear set is keyed to the outer wall of the second rotating shaft; the connecting plate is arranged at the top of the outer wall of the through-hole tube in the front-to-back direction; one end of the spring is installed on the front side of the bottom end of the connecting plate, and the other end of the spring is connected to the bottom end of the inner wall of the shell; the roller seat is installed on the front side of the top of the connecting plate, and the bottom end of the cam is in contact with the top of the roller seat; one end of the telescopic joint is rotatably connected to the top of the inner cavity of the through-hole tube through a bearing.

[0009] Preferably, the hollow shaft is driven to rotate by the first motor under the transmission of the upper and lower gear sets, thereby driving the stirring rod to rotate circumferentially to stir and mix the reactants inside the top liner. During the stirring and mixing process, the connecting gear drives the first shaft to rotate under the action of the top gear set, so that the second shaft drives the cam to rotate, and the side wall of the cam itself intermittently contacts the roller seat to drive the roller seat to squeeze the spring under the cooperation of the connecting plate, so that the connecting plate drives the inner cavity of the hollow shaft to move up and down, thereby realizing intermittent opening and closing of the inside of the nozzle.

[0010] Preferably, the solid pre-processing mechanism comprises: a solid pre-processing mechanism shell, a trough body shell, a guide rail assembly, a lifting frame, an electric grinding disc, a cover body shell, a first electric telescopic rod, a connecting frame, a circular trough body, a drainage joint pipe, a sealing gasket, a second electric telescopic rod, a storage tank, a first pump body and a second pump body; the solid pre-processing mechanism shell is rotatably connected to the top opening of the inner cavity of the top liner through a bearing in the up and down direction; the trough body shell is installed on the right side of the top of the solid pre-processing mechanism shell; the guide rail assembly is arranged on the outside of the left top opening of the solid pre-processing mechanism shell in the up and down direction; the lifting frame is arranged on the right side of the limit end of the guide rail assembly; the electric grinding disc is arranged on the inner side of the lifting frame, and the electric grinding disc is electrically connected to the main console; the cover body shell is installed on the top of the solid pre-processing mechanism shell and is located on the left side of the trough body shell; the first electric telescopic rod is installed at the bottom end of the inner cavity of the cover body shell through a bracket, and the first electric telescopic rod is electrically connected to the main console; the connecting frame is arranged on the top of the inner cavity of the cover body shell, and the right side of the connecting frame is connected by the outside of the trough body shell. The opening of the shell extends to the left side of the lifting frame and is fixedly connected to the lifting frame, and the bottom end of the connecting frame is connected to the telescopic end of the first electric telescopic rod; the circular trough body is arranged at the bottom end of the inner cavity of the trough body shell; the drainage joint pipe is inserted at the bottom opening of the circular trough body; the sealing gasket is arranged on the top of the drainage joint pipe; the second electric telescopic rod is arranged at the bottom end of the inner cavity of the solid pre-processing mechanism shell, the telescopic end of the second electric telescopic rod is fixedly connected to the bottom end of the drainage joint pipe, and the second electric telescopic rod is electrically connected to the main console; the storage tank is installed at the top left front of the solid pre-processing mechanism shell; the first pump body is arranged at the top of the solid pre-processing mechanism shell and is located on the right side of the storage tank, the first pump body and the storage tank are connected through a pipeline, and the first pump body is electrically connected to the main console; the second pump body is arranged at the top of the solid pre-processing mechanism shell and is located on the rear side of the first pump body, the second pump body and the drainage joint pipe are connected through a pipeline, the second pump body is connected to the other end of the telescopic joint through a pipeline, and the second pump body is electrically connected to the main console.

[0011] Preferably, the solid pre-processing mechanism also includes: a guide shell, a quantitative feed roller, a second motor, a feed hopper, a nozzle pipe, a fixed frame, a guide hopper and a third electric telescopic rod; the guide shell is arranged at the top opening on the right side of the inner cavity of the trough shell; the quantitative feed roller is rotatably connected to the right side of the inner cavity of the guide shell through a bearing; the second motor is arranged on the inner side of the guide shell, the rotating end of the second motor is connected to the rear end of the axis of the quantitative feed roller, and the second motor is electrically connected to the main console; the feed hopper is arranged on the top right side of the guide shell, and the bottom end of the inner cavity of the feed hopper is connected to the guide shell The inner cavity of the shell is communicated; the nozzle pipe is arranged at the top left side of the inner cavity of the guide shell, and the guide shell and the first pump body are connected by a pipeline; the fixing frame is installed on the left side of the bottom end of the guide shell; the guide bucket is rotatably connected to the left side of the fixing frame through a pin shaft seat; the number of the third electric telescopic rods is two, one end of the two third electric telescopic rods is rotatably connected to the front and rear ends on the left side of the inner cavity top of the guide shell through a pin shaft seat, and the other ends of the two third electric telescopic rods are respectively rotatably connected to the front and rear ends of the inner side of the guide bucket through a pin shaft seat, and the third electric telescopic rod is electrically connected to the main console.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. Urea granules enter the guide shell through the feed hopper, and the second motor drives the quantitative feeding roller to rotate in the inner cavity of the guide shell, so that the material in the inner cavity of the guide shell is quantitatively discharged. The first pump body quantitatively pumps the formaldehyde solution in the storage tank into the nozzle pipe, so that the nozzle pipe sprays the urea granules and mixes with it. The mixture enters the inner cavity of the circular tank along the guide bucket. After the mixture is quantitatively discharged, the second motor and the first pump body stop working, the third electric telescopic rod shortens and drives the guide bucket to rotate upward, the first electric telescopic rod drives the connecting frame to move downward, and the connecting frame drives the lifting frame to move downward under the limiting action of the guide rail assembly, and the grinding disc inside the electric grinding disc moves to the inner cavity of the circular tank. The motor inside the electric grinding disc drives the grinding disc to rotate to grind the mixture in the inner cavity of the circular tank, so that the urea granules and the formaldehyde solution are fully mixed.

[0013] 2. The hollow shaft is driven to rotate by the first motor under the transmission of the upper and lower gear sets. The hollow shaft drives the stirring rod to rotate circumferentially with the cooperation of the locking frame to stir and mix the reactants inside the top liner. During the stirring and mixing process, the connecting gear drives the first shaft to rotate under the action of the top gear set, and drives the second shaft under the transmission of the bevel gear set, so that the second shaft drives the cam to rotate. The side wall of the cam itself intermittently contacts the roller seat to drive the roller seat to squeeze the spring under the cooperation of the connecting plate, so that the connecting plate drives the inner cavity of the hollow shaft to move up and down, thereby realizing intermittent opening and closing of the inside of the nozzle, and maintaining the connection between the through-hole tube and the second pump body under the expansion and contraction of the expansion joint. The second pump body pressurizes the mixture and discharges it through the through-hole tube and the nozzle to below the liquid level of the formaldehyde solution inside the top liner.

[0014] In summary, the present invention can shorten the reaction time and improve production efficiency by optimizing the mixing and adding process. Uniform mixing and efficient reaction can improve the bonding strength and stability of urea-formaldehyde glue and enhance the quality of the final product. Adding the mixture below the liquid surface can reduce the occurrence of side reactions such as hydrolysis of urea, thereby improving the purity and performance of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Exploded diagram of the reaction mechanism; Figure 3 for Figure 2 Exploded diagram of the reaction mechanism; Figure 4 for Figure 3 A magnified image of point A; Figure 5 for Figure 4 The enlarged view of point B; Figure 6 for Figure 2 Exploded diagram of the solid pre-processing mechanism; Figure 7 for Figure 3 Enlarged view of point C.

[0016] In the figure: 1. main console, 2. reaction mechanism, 21. base shell, 22. bottom liner, 23. discharge pipe, 24. outer shell, 25. temperature control pipe joint, 26. maintenance platform, 27. top liner, 28. pressure relief valve, 29. inlet valve pipe, 3. mixing component, 31. hollow shaft, 32. nozzle, 33. locking frame, 34. stirring rod, 35. through-hole pipe, 36. shell, 37. first motor, 38. gear set, 39. first shaft, 310. connecting gear, 311. second shaft, 312. cam, 313. bevel gear set, 314. connecting plate, 315. spring, 316. roller seat, 317. telescopic joint, 4. solid pre-processing mechanism, 41. solid pre-processing Mechanism shell, 42, trough shell, 43, guide rail assembly, 44, lifting frame, 45, electric grinding disc, 46, cover shell, 47, first electric telescopic rod, 48, connecting frame, 49, circular trough, 410, drainage joint pipe, 411, sealing gasket, 412, second electric telescopic rod, 413, storage tank, 414, first pump body, 415, second pump body, 416, guide shell, 417, quantitative feeding roller, 418, second motor, 419, feeding hopper, 420, nozzle pipe, 421, fixing frame, 422, guiding hopper, 423, third electric telescopic rod, 5, temperature control system, 6, storage box, 7, first delivery pump, 8, base frame, 9, second delivery pump, 10, filter module. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-Figure 7 The present invention provides a technical solution: a process for preparing urea-formaldehyde glue for producing plywood, characterized in that it comprises the following steps: Step 1: Raw material preparation: prepare the following raw materials: urea: purity ≥99%, formaldehyde: concentration 37%, alkaline catalyst: ammonia water, acidic catalyst: hydrochloric acid; Step 2: Prepare the reaction device: clean the reaction device to ensure that there are no impurities, and preheat the heating system to the set temperature; Step 3: Adding materials: Add formaldehyde solution into the reaction device according to the molar ratio of formaldehyde to urea of ​​1.5:1 to 2.0:1, add an appropriate amount of alkaline catalyst, and adjust the pH value to 7.5-9.0; Step 4: Urea addition: pre-processing solid urea so that it is quantitatively mixed with the formaldehyde solution to form a mixture, and adding the mixture to a position below the liquid level of the formaldehyde solution; Step 5: Polycondensation reaction: polycondensation reaction is carried out at a reaction temperature of 80°C-100°C, and the reaction time is usually 1-3 hours, until the desired viscosity is reached; Step 6: Acidification: After the reaction reaches a certain extent, add an acid catalyst and adjust the pH value to 4.5-5.5 to promote resin curing; Step 7: Cooling and adjustment: After the reaction is completed, cool the resin to 40℃-50℃, and adjust the viscosity and solid content as needed. The viscosity is usually between 500-2000cps and the solid content is 50%-70%; Step 8: Filtration: Filter the resin to remove possible impurities.

[0019] The reaction device includes: a main console 1, a reaction mechanism 2, a solid pre-processing mechanism 4, a temperature control system 5, a storage box 6, a first delivery pump 7, a base frame 8, a second delivery pump 9 and a filtering module 10; the reaction mechanism 2 is arranged on the rear side of the main console 1; the solid pre-processing mechanism 4 is arranged on the right side of the reaction mechanism 2; the temperature control system 5 is arranged on the right side of the main console 1, the temperature control system 5 is electrically connected to the main console 1, the temperature control system 5 is controlled by the main console 1, and the temperature control system 5 can discharge the internal heat transfer medium into the outer shell 24 through the pipeline and the temperature control pipe joint 25; the number of storage boxes 6 is two, and the two storage boxes 6 are adjacently arranged on the left side of the main console 1, and the outside of the storage box 6 is provided with a valve to pre-fill itself with formaldehyde solution, alkaline catalyst and acid catalyst and other solution raw materials; the first delivery pump 7 is arranged on the right side of the storage box 6, and the first delivery pump 7 is connected to the two storage boxes 6 through a pipeline The first delivery pump 7 is electrically connected to the main console 1, and the first delivery pump 7 is controlled by the main console 1. The first delivery pump 7 can pump the solution raw materials such as formaldehyde solution, alkaline catalyst and acid catalyst pre-stored in the storage box 6 into the top inner tank 27 through the liquid inlet valve pipe 29 according to the process steps; the base frame 8 is installed at the rear bottom of the reaction mechanism 2; the second delivery pump 9 is installed at the top front side of the base frame 8, the second delivery pump 9 is electrically connected to the main console 1, and the second delivery pump 9 is controlled by the main console 1. The second delivery pump 9 can pump the glue in the bottom inner tank 22 and the top inner tank 27 into the filter module 10 through the discharge pipe 23; the filter module 10 is installed on the top rear side of the base frame 8, the second delivery pump 9 is connected to the filter module 10 through a pipeline, the filter module 10 is electrically connected to the main console 1, and the filter module 10 is controlled by the main console 1 to filter the glue.

[0020] As a preferred solution, further, Figure 2As shown, the reaction mechanism 2 includes: a base shell 21, a bottom liner 22, a discharge pipe 23, an outer shell 24, a temperature control pipe joint 25, a maintenance platform 26, a top liner 27, a pressure relief valve 28, a liquid inlet valve pipe 29 and a mixing component 3; the base shell 21 is fixedly installed at the rear bottom of the main console 1; the bottom liner 22 is arranged on the inner top of the base shell 21; the discharge pipe 23 is arranged in the middle of the bottom end of the discharge pipe 23, one end of the discharge pipe 23 is connected to the bottom of the inner cavity of the bottom liner 22, and the other end of the discharge pipe 23 is connected to the second delivery pump 9; the outer shell 24 is arranged on the outside of the top end of the base shell 21 in the up and down direction; the temperature control pipe joint 25 is installed at the front opening of the outer shell 24, and the temperature control pipe joint 25 It is connected to the temperature control system 5 through a pipeline; the maintenance platform 26 is arranged on the outside of the base shell 21 and the outer shell 24; the top inner tank 27 is installed at the top of the bottom inner tank 22, the bottom of the inner cavity of the top inner tank 27 is communicated with the inner cavity of the bottom inner tank 22, and the top of the top inner tank 27 extends out of the top of the outer shell 24; the pressure relief valve 28 is installed at the top rear opening of the top inner tank 27, the pressure relief valve 28 is electrically connected to the main console 1, the pressure relief valve 28 is controlled by the main console 1, and can perform pressure relief operations on the bottom inner tank 22 and the top inner tank 27 to ensure that the pressures of the bottom inner tank 22 and the top inner tank 27 are stable; the liquid inlet valve pipe 29 is installed at the top opening of the top inner tank 27; the mixing component 3 is arranged in the inner cavity of the top inner tank 27.

[0021] As a preferred solution, further, Figure 3 , Figure 4 and Figure 5As shown, the mixing component 3 includes: a hollow shaft 31, a nozzle 32, a locking frame 33, a stirring rod 34, a through-hole tube 35, a shell 36, a first motor 37, a gear set 38, a first shaft 39, a connecting gear 310, a second shaft 311, a cam 312, a bevel gear set 313, a connecting plate 314, a spring 315, a roller seat 316 and a telescopic joint 317; the hollow shaft 31 is rotatably connected to the top opening of the inner cavity of the top liner 27 through a bearing in the up and down directions; the number of the nozzles 32 is three, and the three nozzles 32 are arranged at intervals from bottom to top at the bottom of the outer wall of the hollow shaft 31; the number of the locking frames 33 is several, and the several locking frames 33 are installed at intervals from top to bottom on the outer wall of the hollow shaft 31; the number of the stirring rods 34 is two groups , the number of stirring rods 34 in each group is several, and the two groups of stirring rods 34 are installed at intervals on the outside of several locking frames 33, and the left and right stirring rods 34 are staggered; the through-hole tube 35 is inserted into the bottom of the inner cavity of the hollow shaft 31 along the up and down direction, and the through-hole tube 35 can move up and down in the inner cavity of the hollow shaft 31; the shell 36 is installed on the top of the top liner 27, and the top of the hollow shaft 31 extends into the bottom of the inner cavity of the shell 36; the first motor 37 is installed on the top of the shell 36, and the rotating end of the first motor 37 extends into the top of the inner cavity of the shell 36. The first motor 37 is electrically connected to the main console 1, and the first motor 37 is controlled by the main console 1. The first motor 37 can drive the driving gear in the top gear set 38 to rotate; the number of gear sets 38 is two, The two gear sets 38 are respectively arranged on the upper and lower sides of the inner cavity of the shell 36. The transmission gears in the two gear sets 38 are connected by a linkage shaft. The driving gears in the two gear sets 38 are respectively connected to the rotating end of the first motor 37 and the top of the outer wall of the hollow shaft 31. The large gear in the gear set 38 serves as a driving gear, and the small gear serves as a transmission gear; the first shaft 39 is rotatably connected to the top of the inner cavity of the shell 36 through a bearing. The connecting gear 310 is keyed to the top of the outer wall of the first shaft 39, and the connecting gear 310 is meshed with the front side of the driving gear of the top gear set 38; the second shaft 311 is rotatably connected to the front side of the outer wall of the shell 36 through a bearing in the front and rear directions; the cam 312 is arranged at the rear end of the axis of the second shaft 311, and the cam 312 is driven by its own rotation The roller seat 316 moves up and down; one end of the bevel gear set 313 is keyed to the bottom end of the first rotating shaft 39, and the other end of the bevel gear set 313 is keyed to the outer wall of the second rotating shaft 311, and the bevel gear set 313 plays a transmission role between the first rotating shaft 39 and the second rotating shaft 311; the connecting plate 314 is arranged on the top of the outer wall of the through-hole tube 35 along the front-to-back direction; one end of the spring 315 is installed on the front side of the bottom end of the connecting plate 314, and the other end of the spring 315 is connected to the bottom end of the inner wall of the outer shell 36; the roller seat 316 is installed on the front side of the top of the connecting plate 314, and the bottom end of the cam 312 contacts the top of the roller seat 316; one end of the telescopic joint 317 is rotatably connected to the top of the inner cavity of the through-hole tube 35 through a bearing, and the telescopic joint 317 itself can be telescopic.

[0022] As a preferred solution, further, Figure 6 and Figure 7As shown, the solid pre-processing mechanism 4 includes: a solid pre-processing mechanism shell 41, a tank shell 42, a guide rail assembly 43, a lifting frame 44, an electric grinding disc 45, a cover shell 46, a first electric telescopic rod 47, a connecting frame 48, a circular tank 49, a drainage joint pipe 410, a sealing gasket 411, a second electric telescopic rod 412, a storage tank 413, a first pump body 414, a second pump body 415, a guide shell 416, a quantitative feeding roller 417, a second motor 418, a feed hopper 419, a nozzle pipe 420, a fixing frame 421, a guide hopper 422 and a third electric telescopic rod 423; the solid pre-processing mechanism shell 41 is connected to the solid pre-processing mechanism by a bearing to rotate in the up and down directions. The top opening of the inner cavity of the top liner 27 is connected; the tank shell 42 is installed on the top right side of the solid pre-processing mechanism shell 41; the guide rail assembly 43 is arranged on the outside of the left top opening of the solid pre-processing mechanism shell 41 along the up and down direction; the lifting frame 44 is arranged on the right side of the limit end of the guide rail assembly 43; the electric grinding disc 45 is arranged on the inner side of the lifting frame 44, the electric grinding disc 45 is electrically connected to the main console 1, the electric grinding disc 45 is controlled by the main console 1, and the internal motor of the electric grinding disc 45 can drive the grinding disc to rotate; the cover shell 46 is installed on the top of the solid pre-processing mechanism shell 41 and is located on the left side of the tank shell 42; the first electric telescopic rod 47 is supported by The frame is installed at the bottom end of the inner cavity of the cover shell 46, the first electric telescopic rod 47 is electrically connected to the main console 1, the first electric telescopic rod 47 is controlled by the main console 1, and the first electric telescopic rod 47 drives the connecting frame 48 to move up and down by its own extension and contraction; the connecting frame 48 is set at the top of the inner cavity of the cover shell 46, the right side of the connecting frame 48 extends from the opening of the slot shell 42 to the left side of the lifting frame 44 and is fixedly connected to the lifting frame 44, and the bottom end of the connecting frame 48 is connected to the telescopic end of the first electric telescopic rod 47; the circular slot body 49 is set at the bottom end of the inner cavity of the slot shell 42; the drainage joint pipe 410 is inserted into the bottom opening of the circular slot body 49; the sealing gasket 41 1 is arranged at the top of the drainage joint pipe 410, and the sealing gasket 411 can seal the opening at the bottom end of the inner cavity of the circular trough body 49; the second electric telescopic rod 412 is arranged at the bottom end of the inner cavity of the solid pre-processing mechanism shell 41, and the telescopic end of the second electric telescopic rod 412 is fixedly connected to the bottom end of the drainage joint pipe 410, and the second electric telescopic rod 412 is electrically connected to the main console 1, and the second electric telescopic rod 412 is controlled by the main console 1. The second electric telescopic rod 412 drives the drainage joint pipe 410 to move up and down by its own extension and shortening; the storage tank 413 is installed at the left front of the top of the solid pre-processing mechanism shell 41, and the storage tank 413 stores formaldehyde solution in advance;The first pump body 414 is arranged at the top of the solid pre-processing mechanism housing 41 and is located on the right side of the storage tank 413. The first pump body 414 and the storage tank 413 are connected through a pipeline. The first pump body 414 is electrically connected to the main console 1. The first pump body 414 is controlled by the main console 1. The first pump body 414 can quantitatively pump the formaldehyde solution in the storage tank 413 into the nozzle pipe 420. The second pump body 415 is arranged at the top of the solid pre-processing mechanism housing 41 and is located on the rear side of the first pump body 414. The second pump body 415 and the discharge joint pipe 410 are connected through a pipeline. The second pump body 415 is connected to the other end of the expansion joint 317 through a pipeline, the second pump body 415 is electrically connected to the main console 1, the second pump body 415 is controlled by the main console 1, and the second pump body 415 discharges the mixture inside the circular tank body 49 into the expansion joint 317 through the joint pipe 410; the guide shell 416 is arranged at the top opening on the right side of the inner cavity of the tank shell 42; the quantitative feeding roller 417 is rotatably connected to the right side of the inner cavity of the guide shell 416 through the bearing; the second motor 418 is arranged on the inner side of the guide shell 416, and the rotating end of the second motor 418 and the quantitative feeding roller 417 are rotatably connected to ... The rear end of the axis of the quantitative feeding roller 417 is connected, the second motor 418 is electrically connected to the main console 1, the second motor 418 is controlled by the main console 1, and the second motor 418 can drive the quantitative feeding roller 417 to rotate; the feed hopper 419 is arranged at the top right side of the guide shell 416, and the bottom end of the inner cavity of the feed hopper 419 is communicated with the inner cavity of the guide shell 416; the nozzle pipe 420 is arranged at the top left side of the inner cavity of the guide shell 416, and the guide shell 416 and the first pump body 414 are connected through a pipeline; the fixing frame 421 is installed on the left side of the bottom end of the guide shell 416; the guide hopper 42 2 is rotatably connected to the left side of the fixing frame 421 through a pin shaft seat; the number of the third electric telescopic rods 423 is two, one end of the two third electric telescopic rods 423 is rotatably connected to the front and rear ends of the left side of the inner cavity top of the guide shell 416 through a pin shaft seat, and the other ends of the two third electric telescopic rods 423 are rotatably connected to the front and rear ends of the inner side of the guide bucket 422 through a pin shaft seat, and the third electric telescopic rod 423 is electrically connected to the main console 1, and the third electric telescopic rod 423 is controlled by the main console 1. The third electric telescopic rod 423 drives the guide bucket 422 to rotate by its own extension and contraction. ;

[0023] The working principle of the urea-formaldehyde glue preparation equipment for plywood production is as follows: Step 1: The staff pre-adds formaldehyde solution, alkaline catalyst, acid catalyst and other solution raw materials into the storage box 6, the staff pre-adds formaldehyde solution into the guide shell 416, the staff puts solid urea granules into the feed hopper 419, the staff controls the main console 1 to start, and the pre-made program in the main console 1 controls the second motor 418, the first pump body 414, the third electric telescopic rod 423, the first electric telescopic rod 47, the electric grinding disc 45, the second electric telescopic rod 412 and the second pump body 415 to start, and the urea granules in the feed hopper 419 enter the guide shell 416, the second motor 418 drives the quantitative unloading roller 417 to rotate in the inner cavity of the guide shell 416, so that the material in the inner cavity of the guide shell 416 is quantitatively discharged, and the first pump body 414 quantitatively pumps the formaldehyde solution in the storage tank 413 into the nozzle pipe 420, so that the nozzle pipe 420 is sprayed on the inside of the urea granules and mixed with it, and the mixture is discharged along the guide hopper 422 The electric grinding disc 45 is driven by the electric motor 410 to move out of the inner cavity of the circular trough 49, and the urea particles and the formaldehyde solution are fully mixed. After the mixing is completed, the first electric telescopic rod 47 is extended to drive the discharge joint pipe 410 to move to the inner cavity of the circular trough 49, and the mixture in the circular trough 49 is discharged into the inner cavity of the circular trough 49. The mixture in the circular trough 49 is discharged into the telescopic joint 317 under the cooperation of the discharge joint pipe 410 and the second pump body 415. Step 2: The prefabricated program inside the main console 1 controls the first delivery pump 7, the temperature control system 5, the first motor 37 and the pressure relief valve 28 to start. The first delivery pump 7 pumps the formaldehyde solution, alkaline catalyst, acid catalyst and other solution raw materials pre-stored in the storage box 6 into the top inner tank 27 through the liquid inlet valve pipe 29 according to the process steps. The temperature control system 5 discharges the internal heat transfer medium into the outer shell 24 through the pipeline and the temperature control pipe joint 25 to achieve temperature control of the reactants in the top inner tank 27. The first motor 37 drives the hollow shaft 31 to rotate under the transmission of the upper and lower gear sets 38. The hollow shaft 31 drives the stirring rod 34 to rotate circumferentially with the cooperation of the locking frame 33 to stir and mix the reactants in the top inner tank 27. During the stirring and mixing process, the connecting gear 310 drives the first shaft 39 to rotate under the action of the top gear set 38. The transmission of the bevel gear set 313 The second rotating shaft 311 is driven downward, so that the second rotating shaft 311 drives the cam 312 to rotate, and the side wall of the cam 312 intermittently contacts the roller seat 316 to drive the roller seat 316 to squeeze the spring 315 under the cooperation of the connecting plate 314, so that the connecting plate 314 drives the inner cavity of the hollow rotating shaft 31 to move up and down, so as to realize the intermittent opening and closing of the inside of the nozzle 32, and maintain the connection between the through-hole pipe 35 and the second pump body 415 under the expansion and contraction of the expansion joint 317. The second pump body 415 pressurizes the mixture and discharges it from the through-hole pipe 35 and the nozzle 32 to below the liquid level of the formaldehyde solution in the top liner 27. The pressure relief valve 28 performs a pressure relief operation on the inside of the top liner 27 by opening and closing itself to ensure that the internal pressure of the top liner 27 is stable. After the reaction is completed, the second delivery pump 9 pumps the glue in the bottom liner 22 and the top liner 27 into the filter module 10 through the discharge pipe 23 for filtration and discharge.

[0024] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing urea-formaldehyde glue for producing plywood, characterized in that: The following steps are involved: Step 1: Raw material preparation: Prepare the following raw materials: Urea: purity ≥99%, formaldehyde: concentration 37%, alkaline catalyst: ammonia water, acidic catalyst: hydrochloric acid; Step 2: Prepare the reaction device: clean the reaction device to ensure that there are no impurities, and preheat the heating system to the set temperature; Step 3: Adding materials: Add formaldehyde solution into the reaction device according to the molar ratio of formaldehyde to urea of ​​1.5:1 to 2.0:1, add an appropriate amount of alkaline catalyst, and adjust the pH value to 7.5-9.0; Step 4: Urea addition: pre-processing solid urea so that it is quantitatively mixed with the formaldehyde solution to form a mixture, and adding the mixture to a position below the liquid level of the formaldehyde solution; Step 5: Polycondensation reaction: polycondensation reaction is carried out at a reaction temperature of 80°C-100°C, and the reaction time is usually 1-3 hours, until the desired viscosity is reached; Step 6: Acidification: After the reaction reaches a certain extent, add an acid catalyst and adjust the pH value to 4.5-5.5 to promote resin curing; Step 7: Cooling and adjustment: After the reaction is completed, cool the resin to 40℃-50℃, and adjust the viscosity and solid content as needed. The viscosity is usually between 500-2000cps and the solid content is 50%-70%; Step 8: Filtration: Filter the resin to remove possible impurities; The reaction device comprises: Main console (1); A reaction mechanism (2) is arranged on the rear side of the main console (1); A solid pre-processing mechanism (4) is arranged on the right side of the reaction mechanism (2); A temperature control system (5) is arranged on the right side of the main console (1), and the temperature control system (5) and the main console (1) are electrically connected; A storage box (6), wherein the number of the storage boxes (6) is two, and the two storage boxes (6) are arranged adjacent to each other on the left side of the main console (1); A first delivery pump (7) is arranged on the right side of the storage box (6), the first delivery pump (7) is connected to the two storage boxes (6) via a pipeline, and the first delivery pump (7) is electrically connected to the main console (1); A base frame (8) mounted on the rear bottom of the reaction mechanism (2); A second delivery pump (9) is installed on the top front side of the base frame (8), and the second delivery pump (9) is electrically connected to the main console (1); The filter module (10) is installed on the top rear side of the base frame (8), the second delivery pump (9) is connected to the filter module (10) through a pipeline, and the filter module (10) is electrically connected to the main console (1).

2. The process for preparing urea-formaldehyde adhesive for producing plywood according to claim 1, characterized in that: The reaction mechanism (2) comprises: A base housing (21) fixedly mounted on the rear bottom of the main console (1); A bottom liner (22) arranged on the inner top of the base shell (21); A discharge pipe (23) is arranged at the middle of the bottom end of the discharge pipe (23), one end of the discharge pipe (23) is connected to the bottom of the inner cavity of the bottom liner (22), and the other end of the discharge pipe (23) is connected to the second delivery pump (9); An outer shell (24) is arranged on the outer side of the top end of the base shell (21) in the up-down direction; A temperature control pipe joint (25) is installed at the front opening of the outer shell (24), and the temperature control pipe joint (25) and the temperature control system (5) are connected via a pipeline; A maintenance platform (26) is arranged outside the base housing (21) and the outer housing (24); A top liner (27) is mounted on the top of the bottom liner (22); the bottom of the inner cavity of the top liner (27) is in communication with the inner cavity of the bottom liner (22); and the top of the top liner (27) extends beyond the top of the outer shell (24); A pressure relief valve (28) is installed at the rear opening of the top end of the top inner tank (27), and the pressure relief valve (28) is electrically connected to the main console (1); A liquid inlet valve pipe (29) installed at the top opening of the top inner tank (27); A mixing component (3) is arranged in the inner cavity of the top inner container (27).

3. The process for preparing urea-formaldehyde adhesive for producing plywood according to claim 2, characterized in that: The mixing component (3) comprises: A hollow rotating shaft (31) is rotatably connected to the top opening of the inner cavity of the top inner container (27) via a bearing in an up-and-down direction; A nozzle (32), wherein the number of the nozzles (32) is three, and the three nozzles (32) are arranged at intervals from bottom to top on the bottom of the outer wall of the hollow rotating shaft (31); A locking frame (33), wherein the number of the locking frames (33) is a plurality, and the plurality of locking frames (33) are installed at intervals from top to bottom on the outer wall of the hollow rotating shaft (31); Stirring rods (34), the number of the stirring rods (34) being two groups, the number of the stirring rods (34) in each group being a plurality, the two groups of stirring rods (34) being installed at intervals on the outsides of a plurality of locking frames (33), and the left and right stirring rods (34) being staggered; A through-hole tube (35) is inserted into the bottom of the inner cavity of the hollow rotating shaft (31) along the up-down direction; An outer shell (36) is mounted on the top of the top inner container (27), and the top end of the hollow rotating shaft (31) extends into the bottom of the inner cavity of the outer shell (36); A first motor (37) is mounted on the top of the housing (36), a rotating end of the first motor (37) extends into the top of the inner cavity of the housing (36), and the first motor (37) is electrically connected to the main console (1); Gear sets (38), the number of the gear sets (38) is two, the two gear sets (38) are respectively arranged on the upper and lower sides of the inner cavity of the housing (36), the transmission gears in the two gear sets (38) are connected via a linkage shaft, and the driving gears in the two gear sets (38) are respectively connected to the rotating end of the first motor (37) and the top end of the outer wall of the hollow rotating shaft (31).

4. A process for preparing urea-formaldehyde adhesive for producing plywood according to claim 3, characterized in that: The mixing component (3) further comprises: A first rotating shaft (39) rotatably connected to the top end of the inner cavity of the housing (36) via a bearing; A connecting gear (310) is key-connected to the top of the outer wall of the first rotating shaft (39), and the connecting gear (310) is meshed with the front side of the driving gear of the top gear set (38); A second rotating shaft (311) is rotatably connected to the front side of the outer wall of the housing (36) via a bearing in the front-to-back direction; A cam (312) is arranged at the rear end of the axis of the second rotating shaft (311); A bevel gear set (313), one end of which is key-connected to the bottom end of the first rotating shaft (39), and the other end of which is key-connected to the outer wall of the second rotating shaft (311); A connecting plate (314) is arranged on the top of the outer wall of the through-hole tube (35) along the front-to-back direction; A spring (315) is mounted at one end on the front side of the bottom end of the connecting plate (314), and the other end of the spring (315) is connected to the bottom end of the inner wall of the housing (36). A roller seat (316) is mounted on the top front side of the connecting plate (314), and the bottom end of the cam (312) is in contact with the top of the roller seat (316); One end of the expansion joint (317) is rotatably connected to the top end of the inner cavity of the through-hole tube (35) via a bearing.

5. A process for preparing urea-formaldehyde adhesive for producing plywood according to claim 4, characterized in that: The first motor (37) drives the hollow rotating shaft (31) to rotate under the transmission of the gear sets (38) on the upper and lower sides, thereby driving the stirring rod (34) to rotate circumferentially to stir and mix the reactants inside the top liner (27). During the stirring and mixing process, the connecting gear (310) drives the first rotating shaft (39) to rotate under the action of the top gear set (38), so that the second rotating shaft (311) drives the cam (312) to rotate, and the side wall of the cam (312) intermittently contacts the roller seat (316) to drive the roller seat (316) to squeeze the spring (315) in cooperation with the connecting plate (314), so that the connecting plate (314) drives the inner cavity of the hollow rotating shaft (31) to move up and down, thereby realizing intermittent opening and closing of the inside of the spray head (32).

6. A process for preparing urea-formaldehyde adhesive for producing plywood according to claim 5, characterized in that: The solid pre-processing mechanism (4) comprises: A solid pre-processing mechanism housing (41) is rotatably connected to the top opening of the inner cavity of the top inner container (27) via a bearing in the up-down direction; A tank housing (42) is mounted on the top right side of the solid pre-processing mechanism housing (41); A guide rail assembly (43) is arranged in the up-down direction outside the left top opening of the solid pre-processing mechanism housing (41); A lifting frame (44) is arranged on the right side of the limiting end of the guide rail assembly (43); An electric grinding disc (45) is arranged on the inner side of the lifting frame (44), and the electric grinding disc (45) is electrically connected to the main console (1); A cover shell (46) mounted on the top of the solid pre-processing mechanism shell (41) and located on the left side of the tank shell (42); A first electric telescopic rod (47) is mounted at the bottom end of the inner cavity of the cover shell (46) via a bracket, and the first electric telescopic rod (47) is electrically connected to the main console (1); A connecting frame (48) is arranged at the top of the inner cavity of the cover body shell (46), the right side of the connecting frame (48) extends from the opening of the tank body shell (42) to the left side of the lifting frame (44) and is fixedly connected to the lifting frame (44), and the bottom end of the connecting frame (48) is connected to the telescopic end of the first electric telescopic rod (47); A circular tank body (49) is arranged at the bottom end of the inner cavity of the tank body shell (42); A liquid discharge joint pipe (410) is inserted into the bottom opening of the circular tank body (49); A sealing gasket (411) is arranged on the top of the liquid discharge joint pipe (410); a second electric telescopic rod (412) disposed at the bottom end of the inner cavity of the solid pre-processing mechanism housing (41), the telescopic end of the second electric telescopic rod (412) being fixedly connected to the bottom end of the liquid discharge joint pipe (410), and the second electric telescopic rod (412) being electrically connected to the main console (1); A storage tank (413) is installed at the front left of the top end of the solid pre-processing mechanism housing (41); a first pump body (414) disposed at the top of the solid pre-processing mechanism housing (41) and located on the right side of the storage tank (413); the first pump body (414) and the storage tank (413) are connected via a pipeline; and the first pump body (414) and the main console (1) are electrically connected; The second pump body (415) is arranged at the top end of the solid pre-processing mechanism housing (41) and is located at the rear side of the first pump body (414); the second pump body (415) and the liquid discharge joint pipe (410) are connected via a pipeline; the second pump body (415) and the other end of the expansion joint (317) are connected via a pipeline; and the second pump body (415) and the main console (1) are electrically connected.

7. A process for preparing urea-formaldehyde adhesive for producing plywood according to claim 6, characterized in that: The solid pre-processing mechanism (4) further comprises: A guide shell (416) is arranged at the top opening of the right side of the inner cavity of the tank shell (42); A quantitative unloading roller (417) is rotatably connected to the right side of the inner cavity of the guide housing (416) via a bearing; A second motor (418) is arranged inside the guide housing (416), a rotating end of the second motor (418) is connected to the rear end of the axis of the quantitative unloading roller (417), and the second motor (418) is electrically connected to the main console (1); A feed hopper (419) is arranged at the top right side of the guide shell (416), and the bottom end of the inner cavity of the feed hopper (419) is in communication with the inner cavity of the guide shell (416); A nozzle pipe (420) is arranged at the top left side of the inner cavity of the guide shell (416), and the guide shell (416) and the first pump body (414) are connected via a pipeline; A fixing frame (421) is installed on the left side of the bottom end of the guide housing (416); A guide bucket (422) is rotatably connected to the left side of the fixing frame (421) via a pin seat; A third electric telescopic rod (423), the number of the third electric telescopic rod (423) is two, one end of the two third electric telescopic rods (423) is rotatably connected to the front and rear ends of the left side of the top of the inner cavity of the guide shell (416) through a pin shaft seat, the other ends of the two third electric telescopic rods (423) are respectively rotatably connected to the front and rear ends of the inner side of the guide bucket (422) through a pin shaft seat, and the third electric telescopic rod (423) is electrically connected to the main console (1).

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