Preparation method of anti-breaking cutting grinding wheel

Abstract

The present application relates to a kind of preparation method of anti-fracture cutting grinding wheel with strength and toughness, which can maintain stable cutting force and anti-fracture performance under high negative pressure condition.The anti-fracture cutting grinding wheel is made of brown corundum, molybdenum disulfide modified phenolic resin, aramid fiber-alumina composite filler, enhanced glass fiber mesh, hexamethylenetetramine and PTFE toughening agent as raw materials.The synergistic effect between aramid fiber-alumina composite filler is utilized to provide high strength, high toughness and high wear resistance, so that the grinding wheel is not easy to break in high load cutting process.Aramid fiber can absorb and disperse stress, and alumina can enhance wear resistance and cutting ability.Molybdenum disulfide modified phenolic resin can reduce the continuous temperature of grinding wheel during high temperature cutting.Molybdenum disulfide is chemically inert, so it is not easy to oxidize at high temperature, thereby protecting the phenolic resin matrix from oxidation damage, and having good thermal stability.The present application is suitable for grinding wheel preparation technical field.

Description

Technical Field

[0001] This invention relates to the field of grinding wheel manufacturing technology, and in particular to a method for manufacturing a fracture-resistant cutting grinding wheel. Background Technology

[0002] With the rapid development of China's machinery manufacturing industry, a growing number of parts in domestic compressor components, hydraulic components, seals, and automotive engines, transmissions, and steering pumps are being machined using grinding wheels for double-end face grinding. Traditional resin grinding wheels suffer from problems because the fillers used in their manufacturing process cannot provide excellent mechanical properties, making it difficult to maintain stability under high-temperature, high-speed cutting environments. Furthermore, the resin binders used cannot provide reliable adhesion. Therefore, traditional resin grinding wheels are prone to breakage under high-load conditions, affecting production efficiency and posing safety hazards. This invention aims to address the problem of grinding wheel breakage by researching both the grinding wheel filler and the modified resin. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and to provide a method for preparing a fracture-resistant cutting wheel that has strength and toughness and can maintain stable cutting force and fracture resistance under high negative pressure conditions.

[0004] The technical solution adopted in this invention is as follows: This invention discloses a method for preparing an anti-fracture cutting wheel, which involves taking the following raw materials in the indicated mass percentages: 50-55% brown fused alumina, 20-25% molybdenum disulfide modified phenolic resin, 10-15% aramid fiber-alumina composite filler, 5-8% reinforced glass fiber mesh, 3-5% hexamethylenetetramine, and 1-2% PTFE toughening agent; including the following steps: S1) Mixing preparation: Weigh out brown fused alumina, molybdenum disulfide modified phenolic resin, aramid fiber-alumina composite filler, reinforced glass fiber mesh, hexamethylenetetramine, and PTFE toughening agent, and mix them evenly to obtain the mixture;

[0005] S2) To manufacture a grinding wheel blank, clean the mold and apply a release agent. Fill the mold with the mixture obtained in S1 and cold press it to form a grinding wheel blank.

[0006] S3) Pre-curing treatment: Place the mold in S2 in an environment with a temperature of 80-100℃ and let it stand for 90 minutes for low-temperature pre-curing;

[0007] S4) Curing: Remove the mold from S3, allow it to cool naturally to room temperature, then transfer it to an oven or curing furnace and set the temperature to 150-200℃ for high-temperature curing.

[0008] S5) Demolding: Remove the mold from the oven or curing oven in S4, allow it to cool naturally or with cold water to room temperature, and then demold to obtain the anti-breakage cutting wheel.

[0009] Furthermore, the molybdenum disulfide modified phenolic resin in step S1 is prepared by the following method:

[0010] a. Weigh molybdenum disulfide powder (purity ≥99%, particle size 1-5μm) and mix it evenly with phenolic resin prepolymer in a certain proportion (the amount of molybdenum disulfide added is usually 5%-20% of the mass of phenolic resin).

[0011] b. Degas the mixture obtained in step a under a vacuum environment;

[0012] c. Cool the mixture obtained in step b to room temperature and preheat it in a mold until the mixture melts and flows in the mold;

[0013] d. Heat the mold in c at high temperature until the phenolic resin undergoes a cross-linking and curing reaction to obtain molybdenum disulfide modified phenolic resin.

[0014] Further, in step b, the mixture is placed in a vacuum drying oven at a temperature of 50-70°C for degassing treatment for 1-2 hours.

[0015] Furthermore, in step c, the preheating temperature is 70-90℃, and the preheating continues for 1-2 hours.

[0016] Further, in step d, the mold is heated to 150-180°C and heated continuously for 3 hours.

[0017] Finally, the aramid fiber-alumina composite filler in step S1 is prepared by the following method: e. First, the acyl chloride group (-COCI) of terephthaloyl chloride undergoes a condensation reaction with the amino group (-NH2) of phenylenediamine to produce polyterephthaloyl chloride;

[0018] f. The PPTA polymer chain formed by the reaction of poly(terephthalamide) obtained in e with p-phenylenediamine (PPTA) and hydrogen chloride (HCl) interacts with each other through hydrogen bonds to obtain filament fiber;

[0019] g. Weigh alumina powder and mix it evenly with the aramid fiber obtained in f to obtain aramid fiber-alumina composite filler.

[0020] The beneficial effects of this invention are as follows: This invention improves upon both the filler and the modified resin. During the mixing process, aramid fiber-alumina composite filler and molybdenum disulfide-modified phenolic resin are added. The aramid fiber-alumina composite filler, through synergistic action, provides comprehensive performance of high strength, high toughness, and high wear resistance, making the grinding wheel less prone to breakage during high-load cutting. Aramid fibers can absorb and disperse stress, while alumina enhances wear resistance and cutting ability, allowing the grinding wheel to maintain stable performance even under prolonged high-intensity use. Simultaneously, the aramid fiber-alumina composite filler can be uniformly distributed within the resin matrix, improving stress distribution and reducing stress concentration through its structural characteristics, further enhancing the grinding wheel's fracture resistance. The addition of molybdenum disulfide-modified phenolic resin can reduce the sustained temperature of the grinding wheel during high-temperature cutting. The chemical inertness of molybdenum disulfide makes it less prone to oxidation at high temperatures, thus protecting the phenolic resin matrix from oxidative damage and exhibiting good thermal stability. Therefore, this invention possesses both strength and toughness, maintaining stable cutting force and fracture resistance under high negative pressure conditions. Detailed Implementation

[0021] This invention provides a method for preparing a grinding wheel, comprising the following raw materials in the indicated mass percentages: 50-55% brown fused alumina, 20-25% molybdenum disulfide modified phenolic resin, 10-15% aramid fiber-alumina composite filler, 5-8% reinforced glass fiber mesh, 3-5% hexamethylenetetramine, and 1-2% PTFE toughening agent; the mixing ratio is shown in the table below.

[0022] Element Weight percentage (%) Brown fused alumina 50～55 Molybdenum disulfide modified phenolic resin 20～25 Finnfiber-alumina composite filler 10～15 Reinforced fiberglass mesh 5～8 Hexamethylenetetramine 3～5 PTFE toughening agent 1～2

[0023] Includes the following steps,

[0024] S1) Preparation of the mixture: Weigh brown fused alumina, molybdenum disulfide modified phenolic resin, aramid fiber-alumina composite filler, reinforced glass fiber mesh, hexamethylenetetramine, and PTFE toughening agent and mix them evenly to obtain the mixture.

[0025] S2) To manufacture a grinding wheel blank, clean the mold and apply a release agent. Fill the mold with the mixture obtained in S1 and cold press it to form a grinding wheel blank.

[0026] S3) Pre-curing treatment: Place the mold in S2 in an environment with a temperature of 80-100℃ and let it stand for 90 minutes for low-temperature pre-curing;

[0027] S4) Curing: Remove the mold from S3, allow it to cool naturally to room temperature, then transfer it to an oven or curing furnace and set the temperature to 150-200℃ for high-temperature curing.

[0028] S5) Demolding: Remove the mold from the oven or curing oven in S4, allow it to cool naturally or with cold water to room temperature, and then demold to obtain the anti-breakage cutting wheel.

[0029] Compared to traditional resin grinding wheels, this invention incorporates aramid fiber-alumina composite filler and molybdenum disulfide-modified phenolic resin during the manufacturing process. In the aramid fiber-alumina composite filler, the aramid fiber molecular chains contain rigid benzene rings and strong hydrogen bonds, giving it extremely high tensile strength and modulus. Simultaneously, hydrogen bonds and intramolecular covalent bonds endow the aramid fibers with high toughness and impact resistance, effectively absorbing and dispersing stress. Alumina has an extremely high Mohs hardness (approximately 9), significantly improving the grinding wheel's wear resistance and cutting ability. The high melting point of alumina (approximately 2054°C) ensures its stability in high-temperature environments. The addition of molybdenum disulfide-modified phenolic resin can reduce the sustained temperature of the grinding wheel during high-temperature cutting. The chemical inertness of molybdenum disulfide makes it less prone to oxidation at high temperatures, thus protecting the phenolic resin matrix from oxidative damage and exhibiting good thermal stability. This invention uses polytetrafluoroethylene (PTFE) toughening agent, which demonstrates excellent stability against almost all acids, alkalis, and organic solvents, greatly improving the chemical corrosion resistance of the composite material. PTFE has a high melting point of 327℃, maintaining chemical stability at high temperatures without degradation or deterioration, further enhancing the thermal stability of the grinding wheel.

[0030] The molybdenum disulfide modified phenolic resin in step S1 is prepared by the following method.

[0031] a. Weigh molybdenum disulfide powder (purity ≥99%, particle size 1-5μm) and mix it evenly with phenolic resin prepolymer in a certain proportion (the amount of molybdenum disulfide added is usually 5%-20% of the mass of phenolic resin).

[0032] b. Place the mixture obtained in step a in a vacuum drying oven at a temperature of 50-70℃ for degassing treatment to eliminate any bubbles that may have been generated in step a. The treatment time is 1-2 hours.

[0033] c. After vacuum degassing, cool the mixture obtained in step b to room temperature. Store the mixture in a sealed container during the cooling process to prevent moisture and oxidation. After cooling, put the mixture into a mold for preheating until the mixture melts and flows in the mold. The preheating temperature is 70-90℃, and the preheating is continued for 1-2 hours.

[0034] d. Heat the mold in c to 150-180℃ and continue heating for 3 hours until the phenolic resin undergoes a cross-linking and curing reaction to obtain molybdenum disulfide modified phenolic resin.

[0035] The molds used in the above steps possess high-temperature resistance and chemical corrosion resistance. Molybdenum disulfide is a layered compound with excellent lubrication and high-temperature resistance. Its layered crystal structure gives it a low coefficient of friction and good lubrication properties. Molybdenum disulfide can maintain its lubrication properties at high temperatures, preventing resin decomposition caused by high temperatures.

[0036] The aramid fiber-alumina composite filler in step S1 is prepared by the following method.

[0037] e. First, the acyl chloride group (-COCI) of terephthaloyl chloride undergoes a condensation reaction with the amino group (-NH2) of phenylenediamine to produce polyterephthaloyl chloride;

[0038] f. The PPTA polymer chain formed by the reaction of poly(p-phenylene terephthalamide) obtained in e with p-phenylenediamine (PPTA) and hydrogen chloride (HCl) interacts with each other through hydrogen bonds to obtain filament fiber (n(COCI-C6H4-COCI)+n(H2N-C6H4-H2N));

[0039] g. Weigh alumina powder and mix it evenly with the aramid fiber obtained in f to obtain aramid fiber-alumina composite filler.

[0040] The aramid fiber-alumina composite filler has the following characteristics:

[0041] 1) High strength and high toughness: Aramid fibers have a rigid aromatic ring structure and strong hydrogen bonding, providing extremely high tensile strength and toughness. The hydrogen bonds between its molecular chains can absorb and disperse stress during the cutting process, preventing the generation and propagation of cracks; the crystal structure of alumina provides high hardness and wear resistance, enabling the grinding wheel to maintain stable performance during high-intensity use.

[0042] 2) High temperature resistance and chemical stability: The chemical inertness and high temperature resistance of aramid fiber make it difficult to decompose in high temperature environments, thus maintaining its mechanical properties; Alumina has a high melting point and chemical corrosion resistance, making it stable in high temperature and chemical corrosion environments.

[0043] 3) Comprehensive performance optimization: The composite filler of aramid fiber and alumina provides high strength, high toughness and high wear resistance through synergistic effect, making the grinding wheel less prone to breakage during high-load cutting; aramid fiber absorbs and disperses stress, while alumina enhances wear resistance and cutting ability, so that the grinding wheel maintains stable performance during long-term high-intensity use;

[0044] 4) Improved stress distribution: Composite fillers can be evenly distributed in the resin matrix, and through their structural characteristics, they can improve stress distribution, reduce stress concentration, and further improve the grinding wheel's resistance to breakage.

[0045] In this invention, the para-hydroxyl groups of molybdenum disulfide can participate in the chain extension reaction of the resin. Through heat treatment or catalytic reaction, covalent bonds are formed between molybdenum disulfide and phenolic resin molecules, enhancing the interfacial bonding force. Simultaneously, the use of PTFE toughening agent effectively improves the toughness and impact resistance of the grinding wheel, significantly reducing the risk of fracture and enhancing overall mechanical strength. Molybdenum disulfide has good lubrication properties, reducing frictional heat generation, decreasing wear, and improving cutting efficiency and grinding wheel lifespan. The addition of molybdenum disulfide and alumina can reduce the sustained temperature of the grinding wheel during high-temperature cutting, and the chemical inertness of molybdenum disulfide makes it less prone to oxidation at high temperatures. This protects the phenolic resin matrix from oxidative damage and prevents thermal degradation during high-temperature cutting, resulting in good thermal stability. Tensile performance tests on the manufactured grinding wheel show that the addition of alumina and aramid fibers significantly improves the elongation at break of the material. The sample achieves high tensile strength, high tensile properties, ideal toughness, and high cutting efficiency. At the same time, aramid fibers and alumina fillers significantly improve the chemical inertness of the grinding wheel, giving it excellent corrosion resistance in acid, alkali, and organic solvent environments. In this invention, the synergistic effect of multiple modified materials enables the grinding wheel to exhibit excellent comprehensive performance under high temperature, high stress, and complex chemical environments.

[0046] This invention, through dual optimization of fillers and modified resins, develops a cutting wheel with excellent fracture resistance, meeting various industrial cutting needs, improving production efficiency, ensuring operational safety, and possessing broad market prospects and application value.

[0047] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. 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 method for preparing a fracture-resistant cutting wheel, characterized in that: Take the following raw materials in the following mass percentages: brown fused alumina 50-55%, molybdenum disulfide modified phenolic resin 20-25%, aramid fiber-alumina composite filler 10-15%, reinforced glass fiber mesh 5-8%, hexamethylenetetramine 3-5%, and PTFE toughening agent 1-2%. Includes the following steps, S1) Preparation of the mixture: Weigh brown fused alumina, molybdenum disulfide modified phenolic resin, aramid fiber-alumina composite filler, reinforced glass fiber mesh, hexamethylenetetramine, and PTFE toughening agent and mix them evenly to obtain the mixture. S2) To manufacture a grinding wheel blank, clean the mold and apply a release agent. Fill the mold with the mixture obtained in S1 and cold press it to form a grinding wheel blank. S3) Pre-curing treatment: Place the mold in S2 in an environment with a temperature of 80-100℃ and let it stand for 90 minutes for low-temperature pre-curing; S4) Curing: Remove the mold from S3, allow it to cool naturally to room temperature, then transfer it to an oven or curing furnace and set the temperature to 150-200℃ for high-temperature curing. S5) Demolding: Remove the mold from the oven or curing oven in S4, allow it to cool naturally or with cold water to room temperature, and then demold to obtain the anti-breakage cutting wheel.

2. The method for preparing a fracture-resistant cutting grinding wheel according to claim 1, characterized in that: The molybdenum disulfide modified phenolic resin in step S1 is prepared by the following method. a. Weigh molybdenum disulfide powder (purity ≥99%, particle size 1-5μm) and mix it evenly with phenolic resin prepolymer in a certain proportion (the amount of molybdenum disulfide added is usually 5%-20% of the mass of phenolic resin). b. Degas the mixture obtained in step a under a vacuum environment; c. Cool the mixture obtained in step b to room temperature and preheat it in a mold until the mixture melts and flows in the mold; d. Heat the mold in c at high temperature until the phenolic resin undergoes a cross-linking and curing reaction to obtain molybdenum disulfide modified phenolic resin.

3. The method for preparing a fracture-resistant cutting grinding wheel according to claim 2, characterized in that: In step b, the mixture is placed in a vacuum drying oven at a temperature of 50-70℃ for degassing treatment for 1-2 hours.

4. The method for preparing a fracture-resistant cutting grinding wheel according to claim 2, characterized in that: In step c, the preheating temperature is 70-90℃, and the preheating continues for 1-2 hours.

5. The method for preparing a fracture-resistant cutting grinding wheel according to claim 2, characterized in that: In step d, heat the mold to 150-180℃ and continue heating for 3 hours.

6. The method for preparing a fracture-resistant cutting grinding wheel according to claim 1, characterized in that: The aramid fiber-alumina composite filler in step S1 is prepared by the following method. e. First, the acyl chloride group (-COCI) of terephthaloyl chloride undergoes a condensation reaction with the amino group (-NH2) of phenylenediamine to produce polyterephthaloyl chloride; f. The PPTA polymer chain formed by the reaction of poly(terephthalamide) obtained in e with p-phenylenediamine (PPTA) and hydrogen chloride (HCl) interacts with each other through hydrogen bonds to obtain filament fiber; Weigh out the alumina powder and mix it evenly with the aramid fiber obtained in f to obtain the aramid fiber-alumina composite filler.