A method for preparing a phenol-formaldehyde resin sphere

Abstract

The present application relates to the technical field of high polymer materials, and particularly relates to a preparation method of phenolic resin spheres. The present application is simple in process and easy to be industrialized, and can complete polymerization and solidification at normal pressure and low temperature by using common sodium phenolate and formaldehyde as raw materials. Through the synergistic dispersion and stabilization of surfactants, polyethylene glycol and polyvinyl alcohol, and in combination with the sphere forming process under acidic solidification conditions, the resin can be effectively controlled to be uniformly dispersed before solidification, and adhesion or agglomeration can be avoided. The obtained phenolic resin spheres are regular in shape, smooth in surface, and narrow in particle size distribution, which can ensure the pre-polymer to be fully crosslinked, promote the solidification depth, increase the crosslinking density in the resin spheres, and thus enhance the pressure resistance, heat resistance and chemical stability of the resin spheres, so that the resin spheres have wide application range and can meet different particle size and performance requirements.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically a method for preparing phenolic resin balls. Background Technology

[0002] Porous carbon materials, due to their high specific surface area, tunable pore structure, and good conductivity, show broad application prospects in the new energy field, especially in the field of silicon-carbon anode materials for lithium-ion batteries, where porous carbon plays a crucial role as a core framework. Loading nano-silicon into the pore structure of porous carbon can effectively buffer the volume expansion of silicon during charge and discharge, improving the cycle stability of the electrode material.

[0003] Currently, the preparation of high-performance porous carbon materials typically uses thermosetting phenolic resin spheres as a precursor, processed through carbonization and activation. Phenolic resin spheres are produced by polymerizing phenol and formaldehyde under alkaline catalysis to generate phenolic resin, which is then cured into spheres under specific conditions. This process is mature, and the resulting porous carbon products have controllable structures and excellent performance, making it the mainstream technology in the field of silicon-carbon anode materials.

[0004] During coal tar processing, a large amount of sodium phenolate aqueous solution is generated as a byproduct, mainly composed of sodium salts of a mixture of phenol, cresol, and xylenol. Currently, the main treatment method for this byproduct is acid hydrolysis to obtain mixed phenols, followed by purification and separation to obtain monomeric phenol products such as phenol, o-cresol, m-cresol, p-cresol, and xylenol. However, this acid hydrolysis process generates a large amount of phenol- and salt-containing wastewater. The phenolic substances are highly toxic and have poor biodegradability, and the high salt content makes wastewater treatment difficult and costly, severely restricting the resource recovery and utilization of sodium phenolate. Some studies have attempted to use carbon dioxide instead of strong acids for decomposition or to perform advanced wastewater treatment for recycling, but these still suffer from drawbacks such as complex processes and low treatment efficiency. No solutions have yet been proposed to address these technical problems. Summary of the Invention

[0005] To address the problems in related technologies, this invention proposes a method for preparing phenolic resin balls to overcome the aforementioned technical issues in existing technologies. The purpose of this invention is to obtain phenolic resin balls using readily available and economically sourced raw materials through simple operation processes and parameters. These balls can be used as a production raw material for porous carbon in silicon-carbon anode materials in the new energy field, meeting performance requirements and significantly reducing production costs. Furthermore, this invention provides a new direction for the resource utilization of coal coking by-products, and the wastewater treatment process is simple and inexpensive, demonstrating promising development prospects.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add sodium phenolate solution to reaction flask, stir and heat to reaction temperature, start adding formaldehyde solution to carry out polymerization reaction, continue to maintain reaction temperature for a period of time after the formaldehyde solution is added, and obtain phenolic resin. Step S2: Add water to adjust the concentration of the phenolic resin, then add surfactant, polyethylene glycol and polyvinyl alcohol, and adjust the pH of the system to acidic with sulfuric acid; Step S3: Heat to the curing temperature. After the phenolic resin is dispersed into spheres, continue to add formaldehyde solution and maintain the curing temperature to carry out the curing reaction. Step S4: Separate and dry to obtain phenolic resin balls.

[0007] Preferably, in step S1, the molar ratio of the sodium phenolate solution to the formaldehyde solution is 1:2.

[0008] Preferably, in step S1, the concentration of the sodium phenolate solution is 20% to 50%.

[0009] Preferably, the surfactant is Span 80.

[0010] Preferably, in step S1, the reaction temperature is 50℃~90℃.

[0011] Preferably, in step S1, the formaldehyde solution is added for 1 to 3 hours, and the reaction temperature is maintained for 2 to 4 hours.

[0012] Preferably, in step S2, water is added to adjust the concentration of the phenolic resin to 10%~30%.

[0013] Preferably, based on the total weight of the phenolic resin after concentration adjustment, the amount of surfactant added is 0.3% to 1%, the amount of polyethylene glycol added is 1% to 2%, and the amount of polyvinyl alcohol added is 0.5% to 1%.

[0014] Preferably, in step S2, the pH value of the system is adjusted to 4-6.

[0015] Preferably, in step S3, the curing temperature is 90℃~100℃, the molar ratio of the formaldehyde solution to the sodium phenolate solution in step S1 is 0.5~1:1, and the curing time after adding the formaldehyde solution is 30min~90min.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention is a method for preparing phenolic resin balls. Common sodium phenolate and formaldehyde are used as raw materials. The polymerization and curing can be completed under normal pressure and low temperature. No high pressure or complex equipment is required. The operation window is wide and it is suitable for large-scale production. Through the synergistic dispersion and stabilization effect of surfactant, polyethylene glycol and polyvinyl alcohol, combined with the balling process under acid curing conditions, the resin can be effectively controlled to be uniformly dispersed before curing, avoiding adhesion or agglomeration. The resulting phenolic resin balls are regular in shape, smooth in surface, and narrow in particle size distribution. (2) This invention is a method for preparing phenolic resin balls. By adopting a two-step aldehyde addition process, the prepolymer is fully cross-linked and the curing depth is promoted, thereby increasing the cross-linking density inside the resin ball and enhancing its compressive strength, heat resistance and chemical stability. It is suitable for adsorption, catalytic carrier or chromatographic packing and other fields. The addition of polyethylene glycol has the functions of pore-forming agent and dispersion stabilizer. By adjusting its dosage and curing time, the pore size and specific surface area of ​​the resin ball can be controlled. (3) This invention is a method for preparing phenolic resin balls. By optimizing the molar ratio of sodium phenolate to formaldehyde and the amount of formaldehyde added during the curing stage, the reaction is ensured to be complete and excessive formaldehyde residue is avoided. The addition of polyvinyl alcohol in the system further reduces the precipitation of free phenol, increases the yield, and reduces the pressure of waste treatment. (4) This invention is a method for preparing phenolic resin balls. By adjusting the dilution concentration, surfactant dosage and curing temperature in S2, resin balls of micron to millimeter size can be flexibly prepared, which can be adapted to various application scenarios such as water treatment, drug sustained release and solid phase extraction. It avoids the large-scale use of organic solvents, and the unreacted formaldehyde can be further consumed in the curing stage, reducing emissions. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0018] Example 1 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 68.80g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 6.0g of polyvinyl alcohol and 13.5g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 54.7g of phenolic resin balls.

[0019] Example 2 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 100g of 45% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 55.30g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 150g of water to dilute and stir evenly. Add 4.2g of polyvinyl alcohol and 9.45g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 2.5g of Span 80 and finally add 6.1g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin is dispersed into spheres, start adding 16g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 44.6g of phenolic resin balls.

[0020] Example 3 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 51.60g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 6.0g of polyvinyl alcohol and 13.5g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 51.6g of phenolic resin balls.

[0021] Example 4 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 86.0g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 6.0g of polyvinyl alcohol and 13.5g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 56.3g of phenolic resin balls.

[0022] Example 5 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 68.80g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 4.8g of polyvinyl alcohol and 13.5g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 55.4g of phenolic resin balls.

[0023] Example 6 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 68.80g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 6.0g of polyvinyl alcohol and 10.8g of polyethylene glycol at 50~55℃ and stir for 10min. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 55.6g of phenolic resin balls.

[0024] Example 7 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 68.80g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 6.0g of polyvinyl alcohol and 13.5g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 56.1g of phenolic resin balls.

[0025] Example 8 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 68.80g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 4.8g of polyvinyl alcohol and 10.8g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.0g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin disperses into spheres, start adding 20g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 53.5g of phenolic resin balls.

[0026] Example 9 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 200g of 28% sodium phenolate solution to the reaction flask, stir and heat to 60℃, and start adding 68.80g of 37% formaldehyde solution dropwise to carry out the polymerization reaction. Control the dropwise temperature at 60~65℃ and the dropwise time at 2h. After the formaldehyde solution is added, continue to maintain the reaction at this temperature for 2h to finish, and obtain phenolic resin. Step S2: After the reaction is complete, add 120g of water to dilute and stir evenly. Add 6.0g of polyvinyl alcohol and 13.5g of polyethylene glycol at 50~55℃ and stir for 10 minutes. Then add 3.5g of Span 80 and finally add 8.6g of 98% sulfuric acid to adjust the pH of the system to 3~4. Step S3: Heat to 90~95℃ and maintain for 30 minutes. After the phenolic resin is dispersed into spheres, start adding 16g of 37% formaldehyde solution dropwise over 10~15 minutes. After adding the formaldehyde solution, continue to maintain for 1 hour to finish. Step S4: Cool to 60~70℃, filter, wash and dry to obtain 56.0g of phenolic resin balls.

[0027] Comparative Example 1 This invention proposes a technical solution for preparing phenolic resin balls: a method for preparing phenolic resin balls, comprising the following steps: Step S1: Add 50g of phenol and 38.81g of 37% formaldehyde solution to the reaction flask, stir well, add 3.0g of hydrochloric acid, and then heat to 90-95℃ and maintain the temperature for 1 hour to finish the reaction. Step S2: Add a solution prepared by 4.0g polyvinyl alcohol and 200g water, maintain at 80-85℃ for 45min, then add 5.5g hexamethylenetetramine and continue to maintain for 1-2h until yellow solid particles appear in the bottle; Step S3: After cooling, filtering, washing with water, and drying, 58.65g of yellow resin ball particles are obtained.

[0028] As shown in Examples 1-9, within the raw material ratios, temperature, and time ranges defined in this invention, phenolic resin balls weighing over 50g can be obtained, with a stable yield between 80% and 92%. The product particles are regularly spherical with a narrow particle size distribution and no agglomeration. While Comparative Example 1 achieved a acceptable yield, the reaction system required the addition of hexamethylenetetramine, and the sphericity formation process was difficult to control, resulting in a less stable product quality compared to this invention.

[0029] In summary, the preparation method provided by this invention effectively solves many shortcomings of the existing technology for preparing phenolic resin balls and has significant industrial application value.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing phenolic resin balls, characterized in that, Includes the following steps: Step S1: Add sodium phenolate solution to reaction flask, stir and heat to reaction temperature, start adding formaldehyde solution to carry out polymerization reaction, continue to maintain reaction temperature for a period of time after the formaldehyde solution is added, and obtain phenolic resin. Step S2: Add water to adjust the concentration of the phenolic resin, then add surfactant, polyethylene glycol and polyvinyl alcohol, and adjust the pH of the system to acidic with sulfuric acid; Step S3: Heat to the curing temperature. After the phenolic resin is dispersed into spheres, continue to add formaldehyde solution and maintain the curing temperature to carry out the curing reaction. Step S4: Separate and dry to obtain phenolic resin balls.

2. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S1, the molar ratio of the sodium phenolate solution to the formaldehyde solution is 1:

2.

3. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S1, the concentration of the sodium phenolate solution is 20% to 50%.

4. The method for preparing phenolic resin balls according to claim 1, characterized in that: The surfactant is Span 80.

5. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S1, the reaction temperature is 50℃~90℃.

6. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S1, the formaldehyde solution is added over a period of 1 to 3 hours, and the reaction temperature is maintained for 2 to 4 hours.

7. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S2, water is added to adjust the concentration of the phenolic resin to 10%~30%.

8. The method for preparing phenolic resin balls according to claim 1, characterized in that: Based on the total weight of the phenolic resin after concentration adjustment, the amount of surfactant added is 0.3%~1%, the amount of polyethylene glycol added is 1%~2%, and the amount of polyvinyl alcohol added is 0.5%~1%.

9. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S2, the pH value of the system is adjusted to 4-6.

10. The method for preparing phenolic resin balls according to claim 1, characterized in that: In step S3, the curing temperature is 90℃~100℃, the molar ratio of the formaldehyde solution to the sodium phenolate solution in step S1 is 0.5~1:1, and the curing time after adding the formaldehyde solution is 30min~90min.