A moisture-proof phenolic resin, a grinding wheel and a preparation method thereof

Abstract

The present application relates to a kind of moisture-proof phenolic resin, grinding wheel and its preparation method, the moisture-proof phenolic resin is made of raw material comprising the following components: phenol 1000 mass parts;37wt% of formaldehyde 1000-1500 mass parts;Organic amine catalyst 30-100 mass parts;Organic acid anhydride 5-30 mass parts;Melamine 50-150 mass parts;Methyl potassium silicate 50-150 mass parts.The moisture-proof phenolic resin is not easy to absorb moisture in air, not easy to form group, can be used to prepare resin grinding wheel, improve the yield of grinding wheel.

Description

Technical Field

[0001] This invention relates to the field of materials, specifically to a moisture-resistant phenolic resin, a grinding wheel, and a method for preparing the same. Background Technology

[0002] The production process of resin grinding wheels generally includes the following main steps: mixing, resting, loading, molding, drying and curing, and packaging. With the automation and rapid advancement of resin grinding wheel production, the loading process has become increasingly automated, but the performance requirements for the rested material are extremely high. Phenolic resin can be used as the resin mixture for resin grinding wheels; however, because ordinary phenolic resin easily absorbs moisture from the air, the mixed material after resting is prone to absorbing moisture and clumping during storage. This leads to uneven material distribution, poor dynamic balance of the grinding wheel, and surface defects during molding, affecting the yield of the resin grinding wheels. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the primary objective of this invention is to provide a moisture-resistant phenolic resin that does not readily absorb moisture from the air, is not prone to clumping, and can be used to prepare resin grinding wheels.

[0004] A second objective of this invention is to provide a method for preparing the moisture-resistant phenolic resin.

[0005] A third objective of this invention is to provide a grinding wheel prepared from the moisture-proof phenolic resin, which has uniform quality and good dynamic balance.

[0006] A fourth objective of this invention is to provide a method for preparing the grinding wheel.

[0007] To achieve the first objective of this invention, this invention provides a moisture-proof phenolic resin, which is prepared from raw materials containing the following components: 1000 parts by weight of phenol; 1000-1500 parts by weight of 37 wt% formaldehyde; 30-100 parts by weight of organic amine catalyst; 5-30 parts by weight of organic acid anhydride; 50-150 parts by weight of melamine; and 50-150 parts by weight of potassium methylsilicate.

[0008] In some embodiments of the present invention, the organic amine catalyst is triethanolamine.

[0009] In some embodiments of the present invention, the organic anhydride is maleic anhydride.

[0010] In some embodiments of the present invention, the raw materials comprise the following components: 1000 parts by weight of phenol; 1200-1300 parts by weight of 37 wt% formaldehyde; 50-60 parts by weight of organic amine catalyst; 10-20 parts by weight of organic acid anhydride; 100-150 parts by weight of melamine; and 100-150 parts by weight of potassium methylsilicate.

[0011] To achieve the second objective of this invention, this invention provides a method for preparing the moisture-proof phenolic resin described in any of the above embodiments, comprising the following steps: Step 1: Adding phenol, a portion of formaldehyde, and an organic amine catalyst into a reaction vessel and reacting at a first temperature for a first preset time; Step 2: Adding the remaining formaldehyde dropwise into the reaction vessel and reacting at a second temperature for a second preset time; Step 3: Adding melamine and continuing the reaction for a third preset time; Step 4: Cooling down, adding organic acid anhydride, and reacting at a third temperature to a preset viscosity; Step 5: Cooling down to a fourth temperature, adding potassium methylsilicate, and discharging the material.

[0012] In some embodiments of the present invention, the portion of formaldehyde is 10-20 wt% of all formaldehyde, and the remaining portion of formaldehyde is the formaldehyde remaining after removing the portion of formaldehyde from all formaldehyde.

[0013] In some embodiments of the present invention, the first temperature is 70-85°C and the first preset time is 30-60 min.

[0014] In some embodiments of the present invention, the second temperature is 90-96°C and the second preset time is 60-90 min.

[0015] In some embodiments of the present invention, the third preset time is 30 to 50 minutes.

[0016] In some embodiments of the present invention, the third temperature is 60-70°C, and the preset viscosity is 10-20 Pa·s.

[0017] In some embodiments of the present invention, the fourth temperature is 30–45°C.

[0018] In some embodiments of the present invention, in step four, maleic anhydride is added to adjust the pH value to a weakly acidic state, wherein adjusting the pH value to a weakly acidic state means adjusting the pH value to 6.5 to 7.0.

[0019] In some embodiments of the present invention, in step five, potassium methylsilicate is added to adjust the pH value to a weakly alkaline state, wherein adjusting the pH value to a weakly alkaline state means adjusting the pH value to 7.0 to 8.0.

[0020] To achieve the third objective of this invention, this invention provides a grinding wheel made from raw materials comprising the following components: 100 parts by weight of abrasive; 7-10 parts by weight of moisture-resistant phenolic resin; 23-25 ​​parts by weight of resin powder; and 10-15 parts by weight of filler; wherein the moisture-resistant phenolic resin is the moisture-resistant phenolic resin described in any of the above embodiments or the moisture-resistant phenolic resin prepared by any of the above preparation methods.

[0021] To achieve the fourth objective of this invention, this invention provides a method for preparing the above-mentioned grinding wheel, comprising the following steps: Step A: mixing resin powder and filler to obtain a first mixture; mixing abrasive and moisture-proof phenolic resin to obtain a second mixture; gradually adding the second mixture to the first mixture and mixing evenly to obtain a final mixture; Step B: allowing the final mixture to stand at a fifth temperature and a first humidity for a fourth preset time; Step C: placing the material obtained in Step B, spreading it flat, shaping it, and drying and curing it.

[0022] In some embodiments of the present invention, the fifth temperature is 16-18°C, the first humidity is 45-50%, and the fourth preset time is 10-12 hours.

[0023] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0024] The moisture-proof phenolic resin of this invention uses organic amines as catalysts and organic acid anhydrides as pH-adjusting acids during the preparation of phenolic resin, avoiding the use of inorganic alkalis and acids, thereby reducing the water absorption of the resin. Simultaneously, melamine is used to modify the phenolic resin, reducing its overall hydrophilicity, and potassium methylsilicate is added as a hydrophobic agent to further reduce the water absorption capacity of the mixed material, thus achieving an overall moisture-proof effect for the phenolic resin. This moisture-proof phenolic resin, used as a resin liquid to prepare resin grinding wheels, results in a mixture that does not easily absorb moisture and clump during storage after setting. The material is evenly distributed during molding, resulting in grinding wheels with good dynamic balance, few surface defects, and a high yield. Detailed Implementation

[0025] The embodiments of the present invention provide a moisture-proof phenolic resin, which can be used to prepare various resin grinding wheels with good quality uniformity, and is particularly beneficial for preparing ultra-thin cutting resin grinding wheels.

[0026] Specifically, the moisture-proof phenolic resin of this embodiment is prepared from raw materials containing the following components: 1000 parts by weight of phenol; 1000-1500 parts by weight of 37 wt% formaldehyde; 30-100 parts by weight of organic amine catalyst; 5-30 parts by weight of organic acid anhydride; 50-150 parts by weight of melamine; and 50-150 parts by weight of potassium methylsilicate. The 37 wt% formaldehyde is an aqueous solution containing formaldehyde, with a formaldehyde mass fraction of 37%. Phenol, organic amine catalyst, organic acid anhydride, melamine, and potassium methylsilicate can all be of industrial grade purity. Phenol and formaldehyde are used as the main raw materials for forming the phenolic resin molecular chain; their condensation polymerization yields a long molecular chain of phenolic resin. The organic amine catalyst is used to catalyze the polymerization of phenol and formaldehyde; compared to inorganic bases, organic amine catalysts can reduce the water absorption of the resin. Organic acid anhydrides, used as pH adjusters, can promote the dehydration of phenolic resin at the end of phenolic polymerization, increasing the degree of polymerization. Compared to inorganic acids, organic acid anhydrides can reduce the water absorption of the resin. Melamine can participate in the polymerization process of phenolic resin, further reducing its hydrophilicity and moisture absorption. Potassium methylsilicate, as a hydrophobic agent, has strong alkalinity and can form polymethylsilicic acid, further improving water resistance.

[0027] This embodiment addresses the problem of ordinary phenolic resin in the prior art easily absorbing water and clumping together, leading to uneven material distribution and affecting the quality of resin grinding wheels. Based on the characteristics of phenolic resin, effective moisture-absorbing modification was performed on the phenolic resin, significantly reducing its water absorption capacity during the feeding process, thereby improving the yield of resin grinding wheels. During the mixing process of resin grinding wheel production, the phenolic resin liquid, as the main binder, encapsulates most of the abrasive, filler, and phenolic resin powder together. The phenolic resin liquid is the main factor affecting the moisture absorption capacity of the material after proofing. Therefore, this embodiment improves the process by reducing the water absorption capacity of the phenolic resin liquid during the feeding process of the resin grinding wheel. The water absorption of phenolic resin is mainly due to the hydroxyl groups on the phenol or the sodium phenolate (or barium phenolate, etc.) after being alkalized by a catalyst. Based on this, the phenolic resin in this embodiment uses organic amines as catalysts and organic acid anhydrides as pH adjusters to reduce the water absorption of phenolic resin. At the same time, melamine is used to modify it to reduce the overall hydrophilicity of the resin. Potassium methylsilicate is also added as a hydrophobic agent to further reduce the water absorption capacity of the mixed material, thereby achieving overall water-resistant performance.

[0028] The main principle behind the above formula's moisture-proof effect is as follows:

[0029] (1) Organic amine catalysts and organic acid anhydrides: In the polymerization process of phenolic resin, if an inorganic base is used as a catalyst, it will react with phenol to form phenolic base, which has a strong ionization ability and easily absorbs moisture. The reaction formula for the formation of phenolic base by reacting phenol with an inorganic base such as NaOH is shown below:

[0030] .

[0031] In this embodiment, the organic amine catalyst does not react with phenol, thus reducing its ionization ability and making it less prone to absorbing moisture.

[0032] Similarly, this embodiment uses organic acid anhydrides instead of inorganic acids as the acid for pH adjustment, which can also reduce material ionization and thus reduce the resin's absorption of moisture.

[0033] (2) Melamine: Melamine is a triazine-based nitrogen-containing heterocyclic organic compound. Its nitrogen-containing six-membered heterocyclic structure is stable and not easily hydrolyzed. Furthermore, the three amino groups on melamine can participate in the polymerization of phenolic resin, binding to the phenolic resin molecular chain. This allows melamine to be stably and uniformly dispersed in the phenolic resin and to act as a cross-linking agent, further improving the waterproof performance of the phenolic resin. The molecular chain obtained by melamine participating in the polymerization of phenolic resin is shown below:

[0034] .

[0035] (3) Potassium methylsilicate: Potassium methylsilicate is strongly alkaline and reacts rapidly with water and carbon dioxide (or other acids) in the air to form polymethylsilicic acid. Polymethylsilicic acid has good hydrophobicity, thus improving waterproof performance. The waterproof mechanism of potassium methylsilicate is shown in the following reaction formula:

[0036]

[0037] As can be seen from the above, this embodiment uses organic amine catalysts, organic acid anhydrides, melamine, and potassium methylsilicate, combined with different aspects of the phenolic resin polymerization process, to modify the phenolic resin to prevent moisture absorption, and finally obtains a phenolic resin with good moisture resistance, which is suitable as a resin liquid for resin grinding wheels.

[0038] In some examples, the raw materials of the moisture-proof phenolic resin of this embodiment consist of the following components: 1000 parts by weight of phenol; 1000-1500 parts by weight of 37 wt% formaldehyde; 30-100 parts by weight of organic amine catalyst; 5-30 parts by weight of organic acid anhydride; 50-150 parts by weight of melamine; and 50-150 parts by weight of potassium methylsilicate. The raw materials of this moisture-proof phenolic resin do not contain any components other than those listed above, further simplifying the formulation.

[0039] In some examples, relative to 1000 parts by weight of phenol, 37 wt% formaldehyde can be 1000, 1100, 1200, 1300, 1400, or 1500 parts by weight; organic amine catalysts can be 30, 40, 50, 60, 70, 80, 90, or 100 parts by weight; and organic acid anhydrides can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 1 7, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 parts by weight; melamine can be 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 parts by weight; potassium methylsilicate can be 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 parts by weight.

[0040] In some examples, the organic amine catalyst is triethanolamine. Triethanolamine is basic, can catalyze the polymerization of phenol and formaldehyde, and does not cause the reactants or reaction products to ionize, thus reducing the water absorption of phenolic resin. Triethanolamine also has the advantage of being readily available as a raw material.

[0041] In some examples, the organic anhydride is maleic anhydride, which can dehydrate the reactants and further promote the reaction. Maleic anhydride itself is a dehydration product of maleic acid and lacks active hydrogen ions, making it difficult for it to generate hydrogen ions. Compared to inorganic acids such as sulfuric acid and hydrochloric acid, maleic anhydride can also reduce the water absorption of phenolic resin.

[0042] In some examples, the raw materials comprise the following components: 1000 parts by weight of phenol; 1200-1300 parts by weight of 37 wt% formaldehyde; 50-60 parts by weight of organic amine catalyst; 10-20 parts by weight of organic acid anhydride; 100-150 parts by weight of melamine; and 100-150 parts by weight of potassium methylsilicate. When the amounts of each component are within the above ranges, the resulting moisture-absorbing phenolic resin can better reduce water absorption.

[0043] In some examples, the preparation method of the above-mentioned moisture-proof phenolic resin includes the following steps:

[0044] Step 1: Add phenol, a portion of formaldehyde, and organic amine catalyst into the reaction vessel and react at a first temperature for a first preset time;

[0045] Step 2: Add the remaining formaldehyde dropwise into the reaction vessel and react at the second temperature for the second preset time;

[0046] Step 3: Add melamine and continue the reaction for the third preset time;

[0047] Step 4: Cool down, add organic acid anhydride, and react at the third temperature to the preset viscosity;

[0048] Step 5: Cool down to the fourth temperature, add potassium methylsilicate, and discharge.

[0049] As can be seen from the above, in the preparation process of phenolic resin in this embodiment, organic amine catalysts, organic acid anhydrides, melamine, and potassium methylsilicate are used for modification at different steps, integrating the water-absorbing modification effects of organic amine catalysts, organic acid anhydrides, melamine, and potassium methylsilicate into each stage of phenolic resin polymerization. Specifically, the organic amine catalyst, as a low-water-absorbing catalyst for the polymerization of phenol and formaldehyde, is added to the reaction vessel, such as a reactor, in step one. To avoid an overly vigorous reaction and better control the degree of polymerization of the phenolic resin, formaldehyde is added in two steps: phenol and formaldehyde undergo initial polymerization in step one, and formaldehyde is gradually added dropwise in step two for further reaction. In step three, melamine is added in the later stages of phenolic resin polymerization, enabling the bonding of six-membered nitrogen heterocycles to the molecular chain of the phenolic resin and increasing the degree of crosslinking, thus reducing the resin's water absorption. In step four, organic acid anhydrides are added as low-water-absorbing pH adjusters to promote resin dehydration and further polymerization. Step 5 involves further mixing potassium methylsilicate into the phenolic resin. Potassium methylsilicate can be evenly dispersed in the phenolic resin. Potassium methylsilicate itself can form hydrophobic polymethylsilicic acid in the air, reducing the water absorption of the resin.

[0050] In some examples, the portion of formaldehyde is 10-20 wt% of all formaldehyde, and the remaining portion of formaldehyde is the formaldehyde remaining after removing the portion of formaldehyde from all formaldehyde, thereby better balancing the polymerization degree of steps one and two and better controlling the polymerization of phenolic resin.

[0051] In some examples, the first temperature is 70–85°C and the first preset time is 30–60 min, allowing phenol and a portion of formaldehyde to be fully prepolymerized.

[0052] In some examples, the second temperature is 90–96°C and the second preset time is 60–90 min, allowing phenol and the prepolymer of phenol and a portion of formaldehyde to further polymerize with the remaining formaldehyde.

[0053] In some examples, the third preset time is 30 to 50 minutes, allowing the phenolic resin and melamine to react fully.

[0054] In some examples, the third temperature is 60-70°C and the preset viscosity is 10-20 Pa·s. Adding organic acid at a slightly lower temperature further promotes the resin dehydration reaction, avoids the reaction being too violent, increases the degree of polymerization of the resin, and obtains the required viscosity, so that the resin liquid can better disperse the abrasive, filler and resin powder in the subsequent preparation of resin grinding wheels.

[0055] In some examples, the fourth temperature is 30–45°C to avoid premature reaction of potassium methylsilicate.

[0056] In some examples, maleic anhydride is added to adjust the pH to a slightly acidic level, specifically to 6.5–7.0. Within this pH range, organic anhydrides can better promote the dehydration polymerization of phenolic resins. The desired pH value can be obtained by introducing an appropriate amount of maleic anhydride.

[0057] In some examples, in step five, potassium methylsilicate is added to adjust the pH to a slightly alkaline state, specifically to 7.0–8.0, which improves the storage stability of the resulting hygroscopic phenolic resin. The pH can be adjusted by introducing an appropriate amount of potassium methylsilicate, or by adding other pH adjusters to obtain the desired pH value.

[0058] In some examples, this embodiment also provides a grinding wheel comprising the aforementioned moisture-absorbing phenolic resin. The grinding wheel is a resin grinding wheel made from raw materials comprising the following components: 100 parts by weight of abrasive; 7-10 parts by weight of moisture-absorbing phenolic resin; 23-25 ​​parts by weight of resin powder; and 10-15 parts by weight of filler. The moisture-absorbing phenolic resin, as a resin liquid, can effectively disperse and bind the abrasive, resin powder, and filler, and improve the overall moisture-absorbing performance of the material.

[0059] In some examples, the raw material of the grinding wheel consists of the following components: 100 parts by weight of abrasive; 7-10 parts by weight of moisture-resistant phenolic resin; 23-25 ​​parts by weight of resin powder; and 10-15 parts by weight of filler. The grinding wheel does not contain any other components besides those listed above. In other embodiments, relative to 100 parts by weight of abrasive, the grinding wheel may also contain 0.5-5 parts by weight of additives, such as pigments.

[0060] In some examples, relative to 100 parts by weight of abrasive; the moisture-resistant phenolic resin may be 7, 8, 9, or 10 parts by weight; the resin powder may be 23, 24, or 25 parts by weight; and the filler may be 10, 11, 12, 13, 14, or 15 parts by weight.

[0061] In some examples, the abrasive may be at least one of silicon carbide, diamond, white fused alumina, and brown fused alumina; the resin powder may be solid phenolic resin powder; and the filler may be at least one of silica sand, alumina, and zirconium oxide.

[0062] In some examples, the above-mentioned method for preparing the grinding wheel includes the following steps:

[0063] Step A: Mix the resin powder and filler to obtain the first mixture; mix the abrasive and the moisture-absorbing phenolic resin to obtain the second mixture; gradually add the second mixture to the first mixture and mix evenly to obtain the final mixture;

[0064] Step B: Allow the final mixture to rest at a fifth temperature and a first humidity for a fourth preset time;

[0065] Step C: Place the material obtained in Step B, spread it out, shape it, and dry and cure it.

[0066] Step A is the mixing step, which ensures a more uniform mixing of phenolic resin powder, abrasive, filler, and resin liquid. Step B involves allowing the final mixture to rest at a fifth temperature and first humidity level for a fourth preset time, a resting step where the mixed material is placed in a low-temperature, low-humidity environment to allow volatile substances to evaporate completely. Step C, material spreading, is the feeding step, typically performed at room temperature using automated, metered or volumetric feeding equipment to spread the rested material. Step C also allows the material to be spread onto a mesh screen, which acts as a framework to further enhance the strength of the resin grinding wheel.

[0067] In some examples, the fifth temperature is 16–18°C, the first humidity is 45–50%, and the fourth preset time is 10–12 hours, thereby improving the material's perming effect.

[0068] In some examples, the average temperature during storage is 25–26°C, the average humidity is 80–85%, and the average storage time is 2–4 hours. This step represents the average environmental parameters and duration for material storage in the grinding wheel production process, awaiting loading.

[0069] The present application will be further described in detail below through specific embodiments. In the following embodiments or comparative examples, the raw materials with the same name have the same source and physical properties, and the steps described are the same.

[0070] Example 1

[0071] The moisture-proof phenolic resin of this embodiment is composed of the following components: 1000 parts by weight of phenol; 1500 parts by weight of 37 wt% formaldehyde; 100 parts by weight of triethanolamine; 30 parts by weight of maleic anhydride; 50 parts by weight of melamine; and 50 parts by weight of potassium methylsilicate.

[0072] The preparation method of the moisture-proof phenolic resin is as follows: Step 1: Phenol, a portion of formaldehyde (15 wt% of total formaldehyde), and triethanolamine are added to a reaction vessel and reacted at 80°C for 50 min; Step 2: The remaining portion of formaldehyde (85 wt% of total formaldehyde) is gradually added dropwise to the reaction vessel and reacted at 95°C for 70 min; Step 3: Melamine is added and the reaction continues for 40 min; Step 4: The temperature is lowered, maleic anhydride is added, and the reaction is carried out at 60°C until the viscosity is about 15 Pa·s; Step 5: The temperature is lowered to about 35°C, potassium methylsilicate is added, and the product is discharged.

[0073] The moisture-proof phenolic resin was used to prepare resin grinding wheels. The raw materials for the resin grinding wheels consist of the following components: 100 parts by weight of abrasive silicon carbide; 7 parts by weight of moisture-proof phenolic resin; 23 parts by weight of solid phenolic resin powder; and 15 parts by weight of filler silica sand.

[0074] The preparation method of this grinding wheel is as follows: Resin powder and filler are mixed evenly to obtain a first mixture; abrasive and resin liquid are mixed evenly to obtain a second mixture. The second mixture is gradually added to the first mixture until it is evenly mixed. The final mixture is placed in an environment at 18℃ and 45% humidity for 12 hours to allow it to rest, then removed and placed in an environment at 25℃ and 8% humidity for a period of time. The mixture is then loaded, shaped, and dried for curing to obtain the resin grinding wheel. The grinding wheel specifications are all 107mm*1.2mm*16mm.

[0075] Example 2

[0076] The moisture-proof phenolic resin of this embodiment is composed of the following components: 1000 parts by weight of phenol; 1300 parts by weight of 37 wt% formaldehyde; 60 parts by weight of triethanolamine; 10 parts by weight of maleic anhydride; 100 parts by weight of melamine; and 150 parts by weight of potassium methylsilicate.

[0077] The preparation method of the moisture-proof phenolic resin, the raw material formula of the resin grinding wheel, and the preparation method of the grinding wheel are the same as those in Example 1 above.

[0078] Example 3

[0079] The moisture-proof phenolic resin of this embodiment is composed of the following components: 1000 parts by weight of phenol; 1200 parts by weight of 37 wt% formaldehyde; 50 parts by weight of triethanolamine; 20 parts by weight of maleic anhydride; 150 parts by weight of melamine; and 100 parts by weight of potassium methylsilicate.

[0080] The preparation method of the moisture-proof phenolic resin, the raw material formula of the resin grinding wheel, and the preparation method of the grinding wheel are the same as those in Example 1 above.

[0081] Example 4

[0082] The moisture-proof phenolic resin of this embodiment is composed of the following components: 1000 parts by weight of phenol; 1000 parts by weight of 37 wt% formaldehyde; 30 parts by weight of triethanolamine; 5 parts by weight of maleic anhydride; 150 parts by weight of melamine; and 150 parts by weight of potassium methylsilicate.

[0083] The preparation method of the moisture-proof phenolic resin, the raw material formula of the resin grinding wheel, and the preparation method of the grinding wheel are the same as those in Example 1 above.

[0084] Comparative Example 1

[0085] In this comparative example, commercially available ordinary phenolic resin liquid was used instead of the moisture-proof phenolic resin in Example 1. The raw material formulation and preparation method of the resin grinding wheel were the same as those in Example 1.

[0086] Comparative Example 2

[0087] This comparative example did not use potassium methylsilicate, and potassium methylsilicate was not added in step five. The other components and their proportions in the moisture-proof phenolic resin, the remaining steps in the preparation method of the moisture-proof phenolic resin, the raw material formulation of the resin grinding wheel, and the preparation method of the grinding wheel are the same as in Example 1 above.

[0088] Comparative Example 3

[0089] In this comparative example, sodium methylsilicate is used to replace potassium methylsilicate in Example 1. The other components and their proportions in the moisture-proof phenolic resin, the preparation method of the moisture-proof phenolic resin, the raw material formulation of the resin grinding wheel, and the preparation method of the grinding wheel are the same as in Example 1 above.

[0090] Performance testing

[0091] (1) Material moisture absorption capacity test

[0092] 100g of the material after resin grinding wheel preparation in the examples and comparative examples was taken, and the weight of water absorbed by the material before and after resting was tested to compare the material's moisture absorption capacity. Simultaneously, the material was placed on a 24-mesh sieve and vibrated for 5 minutes to observe the amount of material remaining on the sieve, comparing the effect of moisture absorption capacity on the particle size. The experimental results are shown in Table 1 below.

[0093] Table 1 Moisture Absorption Capacity Test

[0094]

[0095]

[0096] (2) Grinding wheel quality test

[0097] Grinding wheels were prepared from the resin grinding wheel raw materials used in the above examples and comparative examples after different resting times following the proofing process, and the dynamic balance pass rate of the grinding wheels was tested. The experimental results are shown in Table 2 below.

[0098] Table 2 Grinding wheel quality test

[0099]

[0100]

[0101] As can be seen from the above embodiments and comparative examples, the resin liquid produced using this embodiment will significantly reduce the water absorption performance of the mixture used in the resin grinding wheel. At the same time, the higher the water absorption performance, the more effectively the uniformity of the mixture will be increased, thereby improving the pass rate of dynamic balance during the production process of the resin grinding wheel.

[0102] Finally, it should be emphasized that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A grinding wheel, characterized in that... It is prepared from raw materials containing the following components: 100 parts by weight of abrasive; 7-10 parts by weight of moisture-proof phenolic resin; 23-25 ​​parts by weight of resin powder; 10-15 parts by weight of filler; The method for preparing the grinding wheel includes the following steps: Step A: Mix the resin powder and filler to obtain the first mixture; mix the abrasive and the moisture-absorbing phenolic resin to obtain the second mixture; gradually add the second mixture to the first mixture and mix evenly to obtain the final mixture; Step B: Allow the final mixture to rest at a fifth temperature and a first humidity for a fourth preset time; Step C: Place the material obtained in Step B, spread it out, shape it, and dry and cure it; The moisture-proof phenolic resin is made from raw materials containing the following components: 1000 parts by weight of phenol 37wt% formaldehyde, 1200-1300 parts by weight. 50-60 parts by weight of organic amine catalyst, 10-20 parts by weight of organic acid anhydride 100-150 parts by weight of melamine 100-150 parts by weight of potassium methylsilicate; The organic amine catalyst is triethanolamine; The organic acid anhydride is maleic anhydride; The preparation method of the moisture-proof phenolic resin includes the following steps: Step 1: Add phenol, a portion of formaldehyde, and organic amine catalyst into the reaction vessel and react at a first temperature for a first preset time; Step 2: Add the remaining formaldehyde dropwise into the reaction vessel and react at the second temperature for the second preset time; Step 3: Add melamine and continue the reaction for the third preset time; Step 4: Cool down, add organic acid anhydride, and react at the third temperature to the preset viscosity; Step 5: Cool down to the fourth temperature, add potassium methylsilicate, and discharge.

2. The grinding wheel according to claim 1, characterized in that: The portion of formaldehyde is 10-20 wt% of all formaldehyde, and the remaining portion of formaldehyde is the formaldehyde remaining after removing the portion of formaldehyde from all formaldehyde.

3. The grinding wheel according to claim 2, characterized in that: The first temperature is 70-85℃, and the first preset time is 30-60 min; The second temperature is 90–96°C, and the second preset time is 60–90 min; The third preset time is 30 to 50 minutes; The third temperature is 60-70℃, and the preset viscosity is 10-20 Pa·s; The fourth temperature is 30–45°C.

4. The grinding wheel according to claim 2 or 3, characterized in that: In step four, an organic acid anhydride is added to adjust the pH value to a weakly acidic level, wherein adjusting the pH value to a weakly acidic level means adjusting the pH value to 6.5 to 7.

0. In step five, potassium methylsilicate is added to adjust the pH value to a slightly alkaline state, which means adjusting the pH value to 7.0-8.

0.

5. The method for preparing a grinding wheel according to any one of claims 1 to 4, characterized in that... Includes the following steps: Step A: Mix the resin powder and filler to obtain the first mixture; mix the abrasive and the moisture-absorbing phenolic resin to obtain the second mixture; gradually add the second mixture to the first mixture and mix evenly to obtain the final mixture; Step B: Allow the final mixture to rest at a fifth temperature and a first humidity for a fourth preset time; Step C: Place the material obtained in Step B, spread it out, shape it, and dry and cure it.

6. The preparation method according to claim 5, characterized in that: The fifth temperature is 16-18℃, the first humidity is 45-50%, and the fourth preset time is 10-12h.

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