Preparation method of phenolic resin

Abstract

The invention belongs to the technical field of resin, particularly relates to a preparation method of phenolic resin, and aims to solve the problems of weak bonding strength and high formaldehyde emission in the prior art, the invention provides the following scheme: the preparation method comprises the following steps: S1, taking parts by weight; comprising 35-50 parts of phenol, 25-40 parts of formaldehyde, 3-6 parts of a catalyst, 5-8 parts of modified lime powder and 5-10 parts of modified graphite powder, the phenol needs to be melted into liquid in a water bath at the temperature of 40-50 DEG C for standby application, a 37% aqueous solution is used for the formaldehyde, and the raw materials are crushed by a crushing knife, so that the raw materials can be prevented from caking, the reaction effect of the raw materials is guaranteed, and the production cost is reduced. The height of the stirring rod can be adjusted according to needs, the reaction efficiency of the raw materials can be guaranteed, the bonding strength of the phenolic resin can be guaranteed through material combination of phenol, formaldehyde, the catalyst, the modified lime powder and the modified graphite powder, and meanwhile, due to thorough reaction, the release amount of formaldehyde can be reduced, and the environmental protection performance can be enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of resins, and in particular to a method for preparing a phenolic resin. Background Art

[0002] The Chinese patent document with application number 202111324608.6 discloses a method for preparing a phenolic resin, and in particular relates to a method for preparing a phenolic resin, comprising: ① after phenol and formaldehyde are added, stirring evenly, adding an organic amine catalyst below 45°C, and controlling the pH value between 8.5 and 9.0; ② steam heating to 55°C, heating to 80°C, and maintaining for a period of time; ③ cooling to 70°C, adding melamine; ④ maintaining at 60-70°C for a period of time; ⑤ cooling to 55°C, adding urea; ⑥ maintaining at 50-60°C for a period of time; ⑦ performing vacuum dehydration, controlling the dehydration temperature below 60°C, and after dehydration, adding an ethanol solvent and stirring evenly; ⑧ adding a pre-prepared PVB ethanol solution, stirring evenly, cooling to below 75°C and unloading; the preparation method of the phenolic resin of the present invention can prepare a phenolic resin with low free phenol and free formaldehyde content.

[0003] However, the preparation method of phenolic resin also has some problems. For example, the bonding strength of phenolic resin is weak, and after long-term use, the materials are prone to peeling. Moreover, since phenolic resin uses formaldehyde, it is affected by processing technology. During use, phenolic resin easily releases formaldehyde, which limits its environmental protection. At the same time, the reactors used are mostly general reactors. During the addition process of raw materials, it is difficult to ensure that they will not agglomerate, which affects the reaction effect of the raw materials. The height of the agitator is fixed and cannot be adjusted, which affects the uniformity of mixing. Summary of the Invention

[0004] Based on the problems of weak bonding strength and high formaldehyde release in the background art, the present invention proposes a method for preparing phenolic resin.

[0005] The present invention provides a method for preparing a phenolic resin, comprising the following steps: S1: by weight, including 35 to 50 parts of phenol, 25 to 40 parts of formaldehyde, 3 to 6 parts of catalyst, 5 to 8 parts of modified lime powder and 5 to 10 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for use. Formaldehyde uses a 37% aqueous solution; S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: filtering to remove undispersed lumps or impurities, and placing the filtered resin into a clean, dry, and sealed container to obtain a phenolic resin; The above-mentioned special reactor includes a reactor body, the top of the reactor body is bolted to a transmission box, the left side of the transmission box is bolted to a crushing tank, the left side of the bottom of the crushing tank is connected to a feeding pipe, the bottom end of the feeding pipe is connected to the interior of the reactor body, the interior of the crushing tank is rotatably connected to a rotating shaft, the surface of the rotating shaft is bolted to a crushing knife, the interior of the reactor body is rotatably sleeved with a connecting shaft, the bottom end of the connecting shaft is bolted to a stirring frame, the surface of the connecting shaft is slidably connected to a connecting cylinder, the surface of the connecting cylinder is bolted to a stirring rod, a power mechanism is keyed between the right end of the rotating shaft and the top end of the connecting shaft, and an adjustment mechanism is rotatably sleeved on the top end of the connecting cylinder surface. The preferred materials can be used to crush the raw materials with a crushing knife to avoid agglomeration of the raw materials and ensure the reaction effect of the raw materials. In addition, the height of the stirring rod can be adjusted as needed to ensure the efficiency of the raw material reaction. In addition, the material combination of phenol, formaldehyde, catalyst, modified lime powder and modified graphite powder can ensure the bonding strength of the phenolic resin. At the same time, due to the thorough reaction, the release of formaldehyde can be reduced and the environmental protection performance is enhanced.

[0006] Preferably, in S1, the raw materials of the modified lime powder include lime powder and titanate coupling agent, the treating agent is anhydrous ethanol with a water content of <500ppm, and the weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:1, which can enhance compatibility.

[0007] Preferably, in S1, the preparation method of the modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a fine powder, the particle size is controlled at 5 μm, and dried to a moisture content of <0.5%, the titanate coupling agent is diluted with anhydrous ethanol to a concentration of 10% to 20% to obtain a titanate solution, the diluted titanate solution is added to the reactor, the stirring speed is controlled at 800-1200 rpm, and the lime powder is slowly added, the mass ratio is: lime powder: titanate Coupling agent = 100: 0.5~2.0, the temperature is controlled at 60-70℃, which is lower than the boiling point of ethanol 78℃, to form a uniform slurry with no visible particle agglomeration. The reaction is kept warm for 30-40 minutes, and the system changes from a slurry to a loose powder. The reaction end point is marked by complete evaporation of ethanol. The obtained powder is introduced into the oven and dried and cured in an 80℃ oven for 1 hour to strengthen chemical bonding. Finally, it is crushed again using a jet mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder with good modification effect.

[0008] Preferably, in S1, the preparation method of the modified graphite powder is as follows: obtaining graphite powder, using the strong mechanical shear force of a ball mill to crush the graphite powder into smaller powders, and then using ultraviolet irradiation to treat the surface of the graphite powder to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder, which can effectively enhance the effect of the graphite powder.

[0009] Preferably, the power mechanism includes a power motor, a main bevel gear, a secondary bevel gear and a pulley assembly. The surface of the power motor is bolted to the opening at the bottom right side of the transmission case. The output end of the power motor is key-connected to the axis of the main bevel gear. The teeth of the main bevel gear are engaged with the teeth of the secondary bevel gear. The axis of the secondary bevel gear is key-connected to the top of the connecting shaft. The power motor is key-connected to the pulley assembly. The power supply of the power motor is turned on. The power supply adopts an external power supply or an internal power supply and is controlled by a controller. The power motor can drive the main bevel gear to rotate, the main bevel gear can drive the secondary bevel gear to rotate, and the secondary bevel gear can drive the connecting shaft to rotate.

[0010] Preferably, the pulley assembly includes a driving wheel, a transmission belt and a passive wheel. The surface of the output end of the power motor is key-connected to the axis of the driving wheel, the inner side of the driving wheel is transmission-connected to the bottom end inside the transmission belt, the top end inside the transmission belt is transmission-connected to the inner side of the passive wheel, and the right end of the rotating shaft is key-connected to the axis of the passive wheel. The power motor can drive the driving wheel to rotate, the driving wheel can drive the transmission belt to rotate, and the transmission belt can drive the passive wheel to rotate. The radius of the driving wheel is four times the radius of the passive wheel, which can produce an acceleration effect on the passive wheel, and the passive wheel can drive the rotating shaft to rotate.

[0011] Preferably, the adjusting mechanism includes a reduction motor, a crankshaft, a transmission rod and a reciprocating assembly. The surface of the reduction motor is connected to the left bolt inside the transmission box, the output end of the reduction motor is connected to the top key of the crankshaft, the bottom end of the crankshaft is rotatably sleeved with the inside of the transmission box, the curved part of the crankshaft is rotatably sleeved with the left end of the transmission rod, the transmission rod is hinged to the reciprocating assembly, the power supply of the reduction motor is turned on, the reduction motor is controlled by a controller, the reduction motor is fixed to the transmission box to ensure the stability of the reduction motor, the reduction motor can drive the crankshaft to rotate, the crankshaft is rotatably arranged with the transmission box through a bearing, and the structure of the crankshaft and the transmission rod enables it to drive the transmission rod to move to the left.

[0012] Preferably, the reciprocating assembly includes a rack, a pinion, a rotating rod, an inclined plate and an adjusting assembly. The right end of the transmission rod is hinged to the left end of the rack, the bottom of the rack is slidably connected to the inside of the transmission box, the axis of the pinion is keyed to the top of the rotating rod, the top of the rotating rod surface is rotatably sleeved with the hole on the top of the reactor body, the bottom end of the rotating rod extends to the interior of the reactor body and is keyed to the axis of the inclined plate, the inclined plate is rollingly connected to the adjusting assembly, the transmission rod can drive the rack to move to the left, the rack is slidably set with the transmission box through a slide rail to guide the rack, the rack can drive the pinion to rotate, the pinion can drive the rotating rod to rotate, the rotating rod is rotatably set with the reactor body through a bearing, and the rotating rod can drive the inclined plate to rotate.

[0013] Preferably, the adjustment assembly includes a roller, a connecting frame and a connecting sleeve. There are two rollers. The axes of the two rollers are rotatably connected to the sides of the connecting frame. The surfaces of the two rollers are respectively connected to the right sides of the top and bottom of the inclined plate. The bottom of the connecting frame is bolted to the top of the connecting sleeve. The inside of the connecting sleeve is rotatably sleeved with the top of the surface of the connecting tube. The inclined plate can rotate between the two rollers. The inclined state of the inclined plate can drive the two rollers to move downward, the rollers can drive the connecting frame to move downward, the connecting frame can drive the connecting sleeve to move downward, and the connecting sleeve can drive the connecting tube to move downward.

[0014] Preferably, the sliding holes on both sides of the top of the connecting sleeve are slidably connected with guide rods, the top of the guide rod is connected to the top bolt inside the reactor body, the surface of the connecting shaft is provided with a planar structure, the surface of the connecting shaft is slidably connected to the inside of the connecting tube, the guide rod guides the connecting sleeve to facilitate the up and down movement of the connecting sleeve, and the structure of the connecting shaft makes it convenient for the connecting shaft to drive the connecting tube to rotate, and also allows the connecting tube to move up and down on the surface of the connecting shaft.

[0015] Beneficial effects of the present invention: Optimized materials can be used, and a crushing knife can be added to crush the raw materials to avoid agglomeration of the raw materials and ensure the reaction effect of the raw materials. In addition, the height of the stirring rod can be adjusted as needed to ensure the efficiency of the raw material reaction. In addition, the material combination of phenol, formaldehyde, catalyst, modified lime powder and modified graphite powder can ensure the bonding strength of the phenolic resin. At the same time, due to the thorough reaction, the release of formaldehyde can be reduced and the environmental protection performance can be enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the front structure of the present invention; Figure 2 This is a schematic diagram of the power mechanism structure proposed by the present invention; Figure 3 This is a rear view schematic diagram of the adjustment mechanism proposed by the present invention; Figure 4 This is a schematic diagram of the three-dimensional structure of the connecting sleeve proposed by the present invention; Figure 5 The working flow diagram proposed by the present invention.

[0017] In the figure: 1. Reactor body; 2. Transmission box; 3. Crushing tank; 4. Feeding pipe; 5. Power motor; 6. Main bevel gear; 7. Sub-bevel gear; 8. Connecting shaft; 9. Stirring frame; 10. Driving wheel; 11. Transmission belt; 12. Driven wheel; 13. Rotating shaft; 14. Crushing knife; 15. Reducer motor; 16. Crankshaft; 17. Transmission rod; 18. Rack; 19. Pinion; 20. Rotating rod; 21. Inclined plate; 22. Roller; 23. Connecting frame; 24. Connecting sleeve; 25. Guide rod; 26. Connecting cylinder; 27. Stirring rod. DETAILED DESCRIPTION

[0018] The present invention will be further explained below with reference to specific embodiments.

[0019] Reference Figure 5 , Example 1 This embodiment provides a method for preparing a phenolic resin, comprising the following steps: S1: by weight, including 45 parts of phenol, 35 parts of formaldehyde, 5 parts of catalyst, 7 parts of modified lime powder and 8 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for standby use. Formaldehyde uses a 37% aqueous solution. The raw materials of the modified lime powder include lime powder and titanate coupling agent. The treating agent is anhydrous ethanol with a water content of <500ppm. The weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:1. The preparation method of the modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a tiny powder with a particle size controlled at 5μm, and dried to a moisture content of <0.5%. The titanate coupling agent is diluted with anhydrous ethanol to a concentration of 16% to obtain a titanate solution. The diluted titanate solution is added to the reactor and stirred at a speed of 5000rpm. The speed was controlled at 1100 rpm, and lime powder was slowly added in a mass ratio of lime powder to titanate coupling agent of 100:1.0. The temperature was controlled at 65°C, which was lower than the boiling point of ethanol at 78°C, to form a uniform slurry with no visible particle agglomeration. The reaction was kept warm for 37 minutes, and the system changed from a slurry to a loose powder. The reaction endpoint was marked by complete evaporation of ethanol. The obtained powder was introduced into an oven and dried and cured in an oven at 80°C for 1 hour to strengthen chemical bonding. Finally, the powder was crushed again using a jet mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder. The preparation method of modified graphite powder was as follows: graphite powder was obtained, and the graphite powder was crushed into smaller powders using the strong mechanical shear force of a ball mill. The surface of the graphite powder was then treated with ultraviolet radiation to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder. S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: Filter to remove undispersed lumps or impurities, and put the filtered resin into a clean, dry, and sealed container to obtain phenolic resin.

[0020] Reference Figure 5 , Example 2 This embodiment provides a method for preparing a phenolic resin, comprising the following steps: S1: by weight, including 45 parts of phenol, 34 parts of formaldehyde, 4 parts of catalyst, 8 parts of modified lime powder and 9 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for standby use. Formaldehyde uses a 37% aqueous solution. The raw materials of the modified lime powder include lime powder and titanate coupling agent. The treating agent is anhydrous ethanol with a water content of <500ppm. The weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:1. The preparation method of the modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a tiny powder with a particle size controlled at 5μm, and dried to a moisture content of <0.5%. The titanate coupling agent is diluted with anhydrous ethanol to a concentration of 16% to obtain a titanate solution. The diluted titanate solution is added to the reactor and stirred at a speed of 1000 rpm. The speed was controlled at 1100 rpm, and lime powder was slowly added in a mass ratio of lime powder to titanate coupling agent of 100:1.0. The temperature was controlled at 65°C, which was lower than the boiling point of ethanol at 78°C, to form a uniform slurry with no visible particle agglomeration. The reaction was kept warm for 37 minutes, and the system changed from a slurry to a loose powder. The reaction endpoint was marked by complete evaporation of ethanol. The obtained powder was introduced into an oven and dried and cured in an oven at 80°C for 1 hour to strengthen chemical bonding. Finally, the powder was crushed again using a jet mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder. The preparation method of modified graphite powder was as follows: graphite powder was obtained, and the graphite powder was crushed into smaller powders using the strong mechanical shear force of a ball mill. The surface of the graphite powder was then treated with ultraviolet radiation to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder. S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: Filter to remove undispersed lumps or impurities, and put the filtered resin into a clean, dry, and sealed container to obtain phenolic resin.

[0021] Reference Figure 5 , Example 3 This embodiment provides a method for preparing a phenolic resin, comprising the following steps: S1: by weight, including 44 parts of phenol, 36 parts of formaldehyde, 5 parts of catalyst, 6 parts of modified lime powder and 9 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for standby use. Formaldehyde uses a 37% aqueous solution. The raw materials of the modified lime powder include lime powder and titanate coupling agent. The treating agent is anhydrous ethanol with a water content of <500ppm. The weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:1. The preparation method of the modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a tiny powder with a particle size controlled at 5μm, and dried to a moisture content of <0.5%. The titanate coupling agent is diluted with anhydrous ethanol to a concentration of 16% to obtain a titanate solution. The diluted titanate solution is added to the reactor and stirred at a speed of 5000rpm. The speed was controlled at 1100 rpm, and lime powder was slowly added in a mass ratio of lime powder to titanate coupling agent of 100:1.0. The temperature was controlled at 65°C, which was lower than the boiling point of ethanol at 78°C, to form a uniform slurry with no visible particle agglomeration. The reaction was kept warm for 37 minutes, and the system changed from a slurry to a loose powder. The reaction endpoint was marked by complete evaporation of ethanol. The obtained powder was introduced into an oven and dried and cured in an oven at 80°C for 1 hour to strengthen chemical bonding. Finally, the powder was crushed again using a jet mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder. The preparation method of modified graphite powder was as follows: graphite powder was obtained, and the graphite powder was crushed into smaller powders using the strong mechanical shear force of a ball mill. The surface of the graphite powder was then treated with ultraviolet radiation to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder. S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: Filter to remove undispersed lumps or impurities, and put the filtered resin into a clean, dry, and sealed container to obtain phenolic resin.

[0022] Reference Figure 5 , Example 4 This embodiment provides a method for preparing a phenolic resin, comprising the following steps: S1: by weight, including 45 parts of phenol, 36 parts of formaldehyde, 4 parts of catalyst, 7 parts of modified lime powder and 8 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for standby use. Formaldehyde uses a 37% aqueous solution. The raw materials of the modified lime powder include lime powder and titanate coupling agent. The treating agent is anhydrous ethanol with a water content of <500ppm. The weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:1. The preparation method of the modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a tiny powder with a particle size controlled at 5μm, and dried to a moisture content of <0.5%. The titanate coupling agent is diluted with anhydrous ethanol to a concentration of 16% to obtain a titanate solution. The diluted titanate solution is added to the reactor and stirred at a speed of 5000rpm. The speed was controlled at 1100 rpm, and lime powder was slowly added in a mass ratio of lime powder to titanate coupling agent of 100:1.0. The temperature was controlled at 65°C, which was lower than the boiling point of ethanol at 78°C, to form a uniform slurry with no visible particle agglomeration. The reaction was kept warm for 37 minutes, and the system changed from a slurry to a loose powder. The reaction endpoint was marked by complete evaporation of ethanol. The obtained powder was introduced into an oven and dried and cured in an oven at 80°C for 1 hour to strengthen chemical bonding. Finally, the powder was crushed again using a jet mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder. The preparation method of modified graphite powder was as follows: graphite powder was obtained, and the graphite powder was crushed into smaller powders using the strong mechanical shear force of a ball mill. The surface of the graphite powder was then treated with ultraviolet radiation to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder. S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: Filter to remove undispersed lumps or impurities, and put the filtered resin into a clean, dry, and sealed container to obtain phenolic resin.

[0023] Reference Figure 5 , Example 5 This embodiment provides a method for preparing a phenolic resin, comprising the following steps: S1: by weight, including 42 parts of phenol, 38 parts of formaldehyde, 6 parts of catalyst, 7 parts of modified lime powder and 7 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for standby use. Formaldehyde uses a 37% aqueous solution. The raw materials of the modified lime powder include lime powder and titanate coupling agent. The treating agent is anhydrous ethanol with a water content of <500ppm. The weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:1. The preparation method of the modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a tiny powder with a particle size controlled at 5μm, and dried to a moisture content of <0.5%. The titanate coupling agent is diluted with anhydrous ethanol to a concentration of 16% to obtain a titanate solution. The diluted titanate solution is added to the reactor and stirred at a speed of 5000rpm. The speed was controlled at 1100 rpm, and lime powder was slowly added in a mass ratio of lime powder to titanate coupling agent of 100:1.0. The temperature was controlled at 65°C, which was lower than the boiling point of ethanol at 78°C, to form a uniform slurry with no visible particle agglomeration. The reaction was kept warm for 37 minutes, and the system changed from a slurry to a loose powder. The reaction endpoint was marked by complete evaporation of ethanol. The obtained powder was introduced into an oven and dried and cured in an oven at 80°C for 1 hour to strengthen chemical bonding. Finally, the powder was crushed again using a jet mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder. The preparation method of modified graphite powder was as follows: graphite powder was obtained, and the graphite powder was crushed into smaller powders using the strong mechanical shear force of a ball mill. The surface of the graphite powder was then treated with ultraviolet radiation to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder. S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: Filter to remove undispersed lumps or impurities, and put the filtered resin into a clean, dry, and sealed container to obtain phenolic resin.

[0024] Reference Figure 1-4The above-mentioned special reactor includes a reactor body 1, the top of the reactor body 1 is bolted to a transmission box 2, the left side of the transmission box 2 is bolted to a crushing tank 3, the left side of the bottom of the crushing tank 3 is connected to a feeding pipe 4, the bottom end of the feeding pipe 4 is connected to the interior of the reactor body 1, the interior of the crushing tank 3 is rotatably connected to a rotating shaft 13, the surface of the rotating shaft 13 is bolted to a crushing knife 14, the interior of the reactor body 1 is rotatably sleeved with a connecting shaft 8, the bottom end of the connecting shaft 8 is bolted to a stirring frame 9, the surface of the connecting shaft 8 is slidably connected to a connecting cylinder 26, the surface of the connecting cylinder 26 is bolted to a stirring rod 27, a power mechanism is keyed between the right end of the rotating shaft 13 and the top of the connecting shaft 8, and an adjustment mechanism is rotatably sleeved on the top of the surface of the connecting cylinder 26. The power mechanism includes a power motor 5, a main bevel gear 6, a sub-bevel gear 7 and a pulley assembly. The surface of the power motor 5 is connected with the open bolt at the bottom right side of the transmission case 2. The output end of the power motor 5 is key-connected with the axis of the main bevel gear 6. The teeth of the main bevel gear 6 are meshed with the teeth of the sub-bevel gear 7. The axis of the sub-bevel gear 7 is key-connected with the top of the connecting shaft 8. The power motor 5 is key-connected with the pulley assembly. The power supply of the power motor 5 is connected. The power supply adopts an external power supply or an internal power supply and is controlled by a controller. The power motor 5 can drive the main bevel gear 6 to rotate, the main bevel gear 6 can drive the sub-bevel gear 7 to rotate, and the sub-bevel gear 7 can drive the connecting shaft 8 to rotate. The pulley assembly includes a driving wheel 10, a transmission belt 11 and a driven wheel 12. The power motor 5 The surface of the output end is key-connected with the axis of the driving wheel 10, the inner side of the driving wheel 10 is connected to the bottom end of the transmission belt 11, the top of the transmission belt 11 is connected to the inner side of the passive wheel 12, the right end of the rotating shaft 13 is key-connected with the axis of the passive wheel 12, the power motor 5 can drive the driving wheel 10 to rotate, the driving wheel 10 can drive the transmission belt 11 to rotate, the transmission belt 11 can drive the passive wheel 12 to rotate, the radius of the driving wheel 10 is four times the radius of the passive wheel 12, which can produce an acceleration effect on the passive wheel 12, and the passive wheel 12 can drive the rotating shaft 13 to rotate, the adjusting mechanism includes a reduction motor 15, a crankshaft 16, a transmission rod 17 and a reciprocating assembly, the surface of the reduction motor 15 is connected to the left bolt inside the transmission box 2, the reduction The output end of the speed reduction motor 15 is key-connected to the top of the crankshaft 16, and the bottom end of the crankshaft 16 is rotatably sleeved inside the transmission case 2. The curved portion of the crankshaft 16 is rotatably sleeved to the left end of the transmission rod 17. The transmission rod 17 is hinged to the reciprocating assembly. The power supply of the speed reduction motor 15 is turned on, and the speed reduction motor 15 is controlled by a controller. The speed reduction motor 15 is fixed by the transmission case 2 to ensure the stability of the speed reduction motor 15. The speed reduction motor 15 can drive the crankshaft 16 to rotate. The crankshaft 16 is rotatably arranged with the transmission case 2 through a bearing. The structure of the crankshaft 16 and the transmission rod 17 enables it to drive the transmission rod 17 to move to the left. The reciprocating assembly includes a rack 18, a pinion 19, a rotating rod 20, a tilting plate 21 and an adjusting assembly. The right end of the transmission rod 17 is hinged to the left end of the rack 18.The bottom of the rack 18 is slidably connected to the inside of the transmission box 2, the axis of the pinion 19 is keyed to the top of the rotating rod 20, the top of the surface of the rotating rod 20 is rotatably sleeved with the hole on the top of the reactor body 1, the bottom end of the rotating rod 20 extends to the interior of the reactor body 1 and is keyed to the axis of the inclined plate 21, and the inclined plate 21 is rollingly connected to the adjusting assembly, and the transmission rod 17 can drive the rack 18 to move left, and the rack 18 is slidingly set with the transmission box 2 through the slide rail to guide the rack 18, and the rack 18 can drive the pinion 19 to rotate, and the pinion 19 can drive the rotating rod 20 to rotate, and the rotating rod 20 is rotatably set with the reactor body 1 through the bearing, and the rotating rod 20 can drive the inclined plate 21 to rotate. The adjusting assembly includes a roller 22, a connecting frame 23 and a connecting sleeve 24. There are two rollers 22, and the axis centers of the two rollers 22 are rotatably connected to the side of the connecting frame 23. The surfaces of the two rollers 22 roll with the right side of the top and bottom of the inclined plate 21 respectively. The bottom of the connecting frame 23 is bolted to the top of the connecting sleeve 24, and the interior of the connecting sleeve 24 is rotatably connected to the top of the surface of the connecting cylinder 26. The inclined plate 21 can rotate between the two rollers 22. The inclined state of the inclined plate 21 can drive the two rollers 22 to move downward. The rollers 22 can drive the connecting frame 23 to move downward. The connecting frame 23 can drive the connecting sleeve 24 to move downward. The connecting sleeve 24 can drive the connecting cylinder 26 to move downward. The sliding holes on both sides of the top of the connecting sleeve 24 are slidably connected with guide rods 25. The top of the guide rods 25 is bolted to the top inside the reactor body 1. The surface of the connecting shaft 8 is provided with a flat structure. The surface of the connecting shaft 8 is slidably connected to the interior of the connecting cylinder 26. The guide rods 25 guide the connecting sleeve 24 to facilitate the up and down movement of the connecting sleeve 24. The structure of the connecting shaft 8 makes it convenient for the connecting shaft 8 to drive the connecting cylinder 26 to rotate, and also allows the connecting cylinder 26 to move up and down on the surface of the connecting shaft 8.

[0025] Working principle: Add modified lime powder and modified graphite powder through the feed port of the crushing tank 3, turn on the power of the power motor 5, which adopts an external power supply or an internal power supply and is controlled by the controller. The power motor 5 can drive the main bevel gear 6 to rotate, the main bevel gear 6 can drive the sub-bevel gear 7 to rotate, the sub-bevel gear 7 can drive the connecting shaft 8 to rotate, the connecting shaft 8 can drive the stirring frame 9 to rotate, the connecting shaft 8 can drive the connecting cylinder 26 to rotate, the connecting cylinder 26 can drive the stirring rod 27 to rotate, the power motor 5 can drive the driving wheel 10 to rotate, the driving wheel 10 can drive the transmission belt 11 to rotate, and the transmission belt 11 can drive the passive wheel 12 to rotate. The radius of the active wheel 10 is four times the radius of the passive wheel 12, which can produce an acceleration effect on the passive wheel 12. The passive wheel 12 can drive the rotating shaft 13 to rotate, and the rotating shaft 13 can drive the crushing knife 14 to rotate. The crushing knife 14 can crush the modified lime powder and modified graphite powder inside the crushing tank 3 to avoid agglomeration. Open the valve of the feeding pipe 4 and pour it into the interior of the reactor body 1. When the thickening mixing effect is needed, the power motor 5 can be paused and the reduction The power supply of the speed reduction motor 15 is controlled by a controller. The speed reduction motor 15 is fixed by the transmission box 2 to ensure the stability of the speed reduction motor 15. The speed reduction motor 15 can drive the crankshaft 16 to rotate. The crankshaft 16 is rotated by the bearing and the transmission box 2. The structure of the crankshaft 16 and the transmission rod 17 enables it to drive the transmission rod 17 to move to the left. The transmission rod 17 can drive the rack 18 to move to the left. The rack 18 is slidably set with the transmission box 2 through the slide rail to guide the rack 18. The rack 18 can drive the pinion 19 to rotate. The pinion 19 It can drive the rotating rod 20 to rotate. The rotating rod 20 is rotatably arranged with the reactor body 1 through a bearing. The rotating rod 20 can drive the inclined plate 21 to rotate. The inclined plate 21 can rotate between the two rollers 22. The inclined state of the inclined plate 21 can drive the two rollers 22 to move downward. The rollers 22 can drive the connecting frame 23 to move downward. The connecting frame 23 can drive the connecting sleeve 24 to move downward. The connecting sleeve 24 can drive the connecting tube 26 to move downward. The connecting tube 26 can drive the stirring rod 27 to move downward. In this way, the height of the stirring rod 27 can be adjusted.

[0026] Comparing conventional phenolic resin with the phenolic resin prepared in Examples 1 to 5, the phenolic resins prepared in Examples 1 to 5 are shown in the following table:

[0027] Phenolic resin and industrial flour are evenly mixed to prepare a sizing agent for standby use, wherein the mass ratio of phenolic resin to industrial flour is 4:1; the sizing agents prepared in the above steps are respectively poured into a gluing machine, the gluing amount on both sides of the poplar veneer is controlled to be 350g / m2, and 5 layers of poplar plywood are paved using an interlayer gluing method; the paved substrate is placed in a cold press, and cold pressed at 0.6-0.8MPa for 30-50min; the cold-pressed substrate is placed in a hot press, and hot pressed at a temperature of 140°C and a pressure of 0.8-1MPa, with a hot pressing speed of 1min / mm and a hot pressing time of 15min. The pressure is released and exhausted for 3min, and the pressure is released to 0 to obtain a board.

[0028] The bonding strength of the board was tested according to the national standard GB / T17657-2013, and the test sample size was 10*2.5cm; Boil in boiling water for 4 hours → bake in an oven at (63±3)℃ for 20 hours → boil in boiling water for 4 hours → cool at room temperature for 10 minutes; The formaldehyde emission of the board prepared by the above method was tested according to the desiccant method in the national standard GB / T17657-2013, and the test sample size was 15*5cm.

[0029] It can be seen from the above table that the bonding strength and environmental performance of the phenolic resin prepared by the present invention are significantly improved, and embodiment 2 is the best embodiment.

[0030] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a phenolic resin, characterized in that: The following steps are involved: S1: by weight, including 35 to 50 parts of phenol, 25 to 40 parts of formaldehyde, 3 to 6 parts of catalyst, 5 to 8 parts of modified lime powder and 5 to 10 parts of modified graphite powder. Phenol needs to be melted into liquid in a 40-50℃ water bath for use. Formaldehyde uses a 37% aqueous solution; S2: Get a special reactor, clean and dry it, pass inert gas into it, add molten phenol into the special reactor, start stirring, slowly add catalyst, and slowly drop 70% to 80% of the total formaldehyde solution. Control the drop rate and maintain the reaction temperature at 50-65°C. After the drop addition is completed, keep the reaction at this temperature for 60 to 90 minutes; S3: Slowly add the modified lime powder and modified graphite powder into the reactor in batches while stirring, and keep stirring to ensure that the modified lime powder and modified graphite powder are fully wetted and evenly dispersed by the resin to form a stable suspension. Continue stirring at a temperature of 60-65°C for 30-60 minutes; S4: Slowly add the remaining 20% to 30% formaldehyde solution dropwise into the reactor. After the addition is complete, gradually raise the temperature to 70-85°C and keep stirring for 60 to 180 minutes; S5: filtering to remove undispersed lumps or impurities, and placing the filtered resin into a clean, dry, and sealed container to obtain a phenolic resin; The above-mentioned special reactor includes a reactor body (1), the top of the reactor body (1) is bolted to a transmission box (2), the left side of the transmission box (2) is bolted to a crushing tank (3), the left side of the bottom of the crushing tank (3) is connected to a feeding pipe (4), the bottom end of the feeding pipe (4) is connected to the inside of the reactor body (1), the inside of the crushing tank (3) is rotatably connected to a rotating shaft (13), the surface of the rotating shaft (13) is bolted to a crushing knife (14), the inside of the reactor body (1) is rotatably sleeved with a connecting shaft (8), the bottom end of the connecting shaft (8) is bolted to a stirring frame (9), the surface of the connecting shaft (8) is slidably connected to a connecting cylinder (26), the surface of the connecting cylinder (26) is bolted to a stirring rod (27), a power mechanism is keyed between the right end of the rotating shaft (13) and the top end of the connecting shaft (8), and an adjustment mechanism is rotatably sleeved on the top end of the surface of the connecting cylinder (26).

2. The method for preparing a phenolic resin according to claim 1, wherein In S1, the raw materials of the modified lime powder include lime powder and titanate coupling agent, the treating agent is anhydrous ethanol with a water content of <500ppm, and the weight ratio of lime powder to titanate coupling agent in the modified lime powder is controlled at 20:

1.

3. The method for preparing a phenolic resin according to claim 2, wherein In S1, the preparation method of modified lime powder is as follows: lime powder is obtained, poured into the interior of the airflow mill, the airflow mill is started, the lime powder is ground into a fine powder with a particle size controlled at 5 μm, and dried to a moisture content of <0.5%. The titanate coupling agent is diluted with anhydrous ethanol to a concentration of 10% to 20% to obtain a titanate solution, the diluted titanate solution is added to the reactor, the stirring speed is controlled at 800-1200 rpm, and lime powder is slowly added at a mass ratio of lime powder to titanate coupling agent = 100: 0.5~2.

0. The temperature is controlled at 60-70°C, which is lower than the boiling point of ethanol at 78°C, to form a uniform slurry without visible particle agglomeration, and the reaction is kept warm for 30-40 minutes until the system changes from a slurry to a loose powder, indicating the end point of the reaction, and the ethanol is completely volatilized. The obtained powder is introduced into the interior of an oven, dried and solidified in an oven at 80°C for 1 hour to strengthen chemical bonding, and finally pulverized again using a airflow mill and sieved through 300 mesh to ensure particle uniformity to obtain modified lime powder.

4. The method for preparing a phenolic resin according to claim 1, wherein In S1, the preparation method of the modified graphite powder is as follows: obtaining graphite powder, using the strong mechanical shear force of a ball mill to crush the graphite powder into smaller powders, and then using ultraviolet radiation to treat the surface of the graphite powder to generate active sites of free radicals on the surface of the graphite powder to obtain modified graphite powder.

5. The method for preparing a phenolic resin according to claim 1, wherein The power mechanism comprises a power motor (5), a main bevel gear (6), a secondary bevel gear (7) and a pulley assembly, wherein the surface of the power motor (5) is bolt-connected to the opening at the bottom right side of the transmission case (2), the output end of the power motor (5) is key-connected to the axis of the main bevel gear (6), the teeth of the main bevel gear (6) are meshed with the teeth of the secondary bevel gear (7), the axis of the secondary bevel gear (7) is key-connected to the top end of the connecting shaft (8), and the power motor (5) is key-connected to the pulley assembly.

6. The method for preparing a phenolic resin according to claim 5, wherein: The pulley assembly comprises a driving wheel (10), a transmission belt (11) and a driven wheel (12); the surface of the output end of the power motor (5) is key-connected to the axis of the driving wheel (10); the inner side of the driving wheel (10) is transmission-connected to the bottom end of the transmission belt (11); the top end of the transmission belt (11) is transmission-connected to the inner side of the driven wheel (12); and the right end of the rotating shaft (13) is key-connected to the axis of the driven wheel (12).

7. The method for preparing a phenolic resin according to claim 1, wherein The regulating mechanism comprises a reduction motor (15), a crankshaft (16), a transmission rod (17) and a reciprocating assembly, wherein the surface of the reduction motor (15) is bolted to the left side of the transmission case (2), the output end of the reduction motor (15) is key-connected to the top end of the crankshaft (16), the bottom end of the crankshaft (16) is rotatably sleeved to the inside of the transmission case (2), the curved portion of the crankshaft (16) is rotatably sleeved to the left end of the transmission rod (17), and the transmission rod (17) is hinged to the reciprocating assembly.

8. The method for preparing a phenolic resin according to claim 7, wherein: The reciprocating assembly comprises a rack (18), a pinion (19), a rotating rod (20), an inclined plate (21) and an adjusting assembly, wherein the right end of the transmission rod (17) is hinged to the left end of the rack (18), the bottom of the rack (18) is slidably connected to the interior of the transmission box (2), the axis of the pinion (19) is keyed to the top end of the rotating rod (20), the top end of the surface of the rotating rod (20) is rotatably sleeved to the hole at the top of the reactor body (1), the bottom end of the rotating rod (20) extends to the interior of the reactor body (1) and is keyed to the axis of the inclined plate (21), and the inclined plate (21) is rollingly connected to the adjusting assembly.

9. The method for preparing a phenolic resin according to claim 8, wherein: The adjustment assembly includes a roller (22), a connecting frame (23) and a connecting sleeve (24), wherein two rollers (22) are provided, and the axis centers of the two rollers (22) are rotatably connected to the side of the connecting frame (23), and the surfaces of the two rollers (22) are respectively connected to the right sides of the top and bottom of the inclined plate (21) in a rolling manner, and the bottom of the connecting frame (23) is connected to the top of the connecting sleeve (24) by bolts, and the interior of the connecting sleeve (24) is rotatably sleeved to the top of the surface of the connecting cylinder (26).

10. The method for preparing a phenolic resin according to claim 9, wherein: The sliding holes on both sides of the top of the connecting sleeve (24) are slidably connected to guide rods (25), the top of the guide rods (25) is connected to the top bolt inside the reactor body (1), the surface of the connecting shaft (8) is provided with a flat structure, and the surface of the connecting shaft (8) is slidably connected to the inside of the connecting cylinder (26).

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