Large-particle-size diamond coated grinding belt and preparation process and application thereof

Abstract

The invention provides a large-particle-size diamond coating grinding belt and a preparation process and application thereof. The grinding belt sequentially comprises a flexible base material, a diamond coating and a glue coating layer from inside to outside. The diamond coating is prepared from 30 to 55 parts of large-particle-size diamond micro powder, 5 to 10 parts of aluminum oxide micro powder, 3 to 10 parts of a thickening agent and 25 to 62 parts of low-TG-point polyurethane resin; the adhesive coating layer comprises the following components in parts by weight: 10-40 parts of epoxy resin and 60-90 parts of polyurethane resin with a high TG point; the preparation process comprises the following steps: preparing coating liquid for preparing the diamond coating; preparing glue coating liquid for preparing a glue coating layer; coating a base material with the coating liquid to form a diamond coating; coating the diamond coating with the coating liquid; and the product coated with the glue is rewound and cured. High-strength combination of the large-particle diamond and the resin binding agent can be achieved, meanwhile, the abrasive particle exposure height and the cutting efficiency are improved, the preparation process is simple, and the cost is controllable.

Description

Technical Field

[0001] This invention relates to the field of superhard material coating technology, and more specifically, to a large-particle-diameter diamond-coated abrasive belt, its preparation process, and its application, particularly suitable for abrasive belts, abrasive discs, and other grinding tools for precision grinding of high-hardness materials. Background Technology

[0002] Diamond-coated abrasive belts hold a core position in high-end manufacturing due to their irreplaceable hardness and lifespan advantages, but cost and technological barriers remain major obstacles to widespread adoption. In the future, with accelerated innovation in coating processes and domestic substitution, this product is expected to achieve wider applications in semiconductors, new energy, and other fields, while continuously iterating towards ultra-precision and environmentally friendly directions.

[0003] With the rapid development of high-end manufacturing industries such as semiconductors, optical glass, ceramics, and cemented carbide, the demand for diamond abrasive belts continues to rise. Applications include precision grinding and polishing of silicon carbide (SiC) wafers in the semiconductor industry; processing of sapphire glass (for mobile phone screens and camera covers) in the 3C industry; grinding of roller components in the automotive industry; and processing and polishing of rollers in the paper industry. Globally, the diamond-coated abrasives market is projected to exceed $1 billion in 2023, with an annual growth rate of approximately 8%-10%.

[0004] Currently, there are still some problems with large-particle-coated diamond abrasive paper products. The main problems are as follows: 1. Insufficient adhesion: Large diamond particles have a small specific surface area and weak interfacial bonding with the resin binder, making them prone to falling off during high-speed grinding. Since the grinding belt products are all in a single layer of uniformly distributed diamond particles, the larger the particles, the less stable their fixation in the resin binder. The particles are not easily supported, and under high grinding tension and speed, the particles are prone to falling off, causing scratches and reducing the product's continuous grinding ability. 2. Low cutting force: In the manufacturing process of traditional coated abrasive belts, the diamond particles are excessively coated with resin, resulting in an insufficient proportion of effective cutting edges (usually <40%). If the solid content of the diamond particles is increased, firstly, particle sedimentation will easily occur during the slurry preparation and dispersion process, resulting in a decrease in the effective coating rate; secondly, the adhesive content in the coating will decrease, reducing the bonding effect of fixing the diamond particles and causing a significant decrease in cutting force. 3. Short lifespan: The poor heat resistance of the binder causes the resin to soften at high temperatures, leading to premature failure of the abrasive grains; in addition, the choice of substrate film will also reduce the adhesion of the coating, resulting in the shedding of abrasive grains during the grinding process and the end of the lifespan.

[0005] Based on the above problems, existing solutions include surface roughening treatment and adding coupling agents. The drawbacks of surface roughening treatment are: although chemical etching or plasma treatment can improve the bonding force, it will damage the strength of diamond (strength loss of about 15-30%), and the cost of grinding belts will increase significantly. The drawbacks of adding coupling agents are: silane coupling agents only improve the bonding of micron-sized particles and have a certain anti-settling effect, but their effect on large diamond particles is limited.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a large-particle-diameter diamond-coated abrasive belt, its preparation process, and its application. This invention achieves a high-strength bond between large-particle diamond and resin binder, while simultaneously improving the abrasive grain tip height and cutting efficiency. The preparation process is simple and cost-controllable.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A large-particle-size diamond-coated abrasive belt comprises, from the inside out: a flexible substrate, a diamond coating, and an adhesive layer; The diamond coating comprises the following components by weight: 30-55 parts of large-particle-size diamond micro powder, 5-10 parts of alumina micro powder, 3-10 parts of thickener, and 25-62 parts of low-TG point polyurethane resin. The adhesive layer comprises the following components by weight: 10-40 parts epoxy resin and 60-90 parts high TG point polyurethane resin.

[0009] Furthermore, the flexible substrate is a PET tape base or a polyimide high-temperature resistant film substrate with a thickness of 75~125μm.

[0010] Furthermore, the particle size of the large-particle-size diamond micro powder is 40~200μm, and the thickness of the diamond coating is ±10μm of the particle size of the large-particle-size diamond micro powder.

[0011] Furthermore, the particle size of the alumina micro powder is 3~6μm.

[0012] Furthermore, the thickener is one or a combination of bentonite, nano-silica, cellulose, fatty alcohol, fatty acid, ether, and associative polyurethane thickeners.

[0013] Furthermore, the polyurethane resin with a low TG point is a polyurethane resin with a TG ≤ 30℃.

[0014] Furthermore, the thickness of the adhesive layer is 3~10μm.

[0015] Furthermore, the high TG point polyurethane resin is a polyurethane resin with TG ≥ 55℃.

[0016] Furthermore, the epoxy equivalent of the epoxy resin is 1000~3000 g / eq.

[0017] The above-mentioned process for preparing large-particle-size diamond-coated abrasive belts includes the following steps: Step S1: Prepare the coating solution for preparing the diamond coating; Step S2: Prepare the adhesive liquid for preparing the adhesive layer; Step S3: Apply the coating liquid onto the substrate to form a diamond coating; Step S4: Apply the adhesive liquid onto the diamond coating; Step S5: Rewind and cure the coated product.

[0018] Further, the method for preparing the coating liquid for diamond coating in step S1 is as follows: add a mixed adhesive of low TG point polyurethane resin to large-particle-size diamond micro powder in a certain proportion, add a mixed solvent, add alumina micro powder and thickener in a certain proportion, disperse fully to obtain a slurry, add polyurethane curing agent to the slurry to obtain the coating liquid.

[0019] Further, step S2 involves preparing the adhesive liquid for the coating layer as follows: take a mixture of polyurethane resin and epoxy resin with a high TG point in proportion, add a mixed solvent, add a polyurethane curing agent, and disperse evenly to obtain the adhesive liquid.

[0020] Furthermore, in step S5, during the rewinding process of the coating machine, the drying tunnel is heated in three zones; in step S5, the curing adopts a gradient curing process, first curing at 35~80℃ for 1~24h, and then curing at 60~100℃ for 12~48h.

[0021] The above-mentioned large-particle-size diamond-coated abrasive belts and the above-mentioned preparation process of large-particle-size diamond-coated abrasive belts are applied in the preparation of large-particle-size diamond-coated abrasive belts and large-particle-size diamond-coated abrasive discs.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention relates to a large-particle-diameter diamond-coated abrasive belt and its preparation process, which achieves a high-strength bond between large-particle diamond and resin binder, while improving the abrasive grain tip height and cutting efficiency. The preparation process is simple and cost-controllable.

[0023] 2. The present invention relates to a large-particle-size diamond-coated abrasive belt and its preparation process. By coating large-particle diamond micro-powder with a resin binder into a thin film, multi-layer coating can significantly improve the coating adhesion of the large-particle diamond abrasive belt product and the cutting force during product use, ensuring that the workpiece being ground can have a continuous and stable removal effect.

[0024] 3. The large-particle-size diamond-coated abrasive belt of this invention uses a slurry configuration of matrix resin and large-particle-size diamond micropowder, which ensures a high diamond micropowder content. This high powder content increases the density of the diamond particles arranged in a single layer within the coating, while maintaining sufficient surface area of ​​the diamond particles exposed outside the adhesive layer, laying the foundation for improved cutting force. The addition of fine-grained alumina micropowder, as a reinforcing phase, increases fixation sites in the coating, filling the spaces between the low-density diamond particles in the matrix resin with solids, enhancing the anti-collapse resistance of the effective abrasive particles during product use. The fine-grained alumina micropowder fills the resin microcracks and forms a mechanical interlock with the large-particle diamond micropowder, improving adhesion. The selection of small-particle-size alumina micropowder serves two purposes: firstly, it does not affect the exposure of the large-particle diamond grinding edge, and secondly, it acts as a semi-fixing agent.

[0025] 4. The large-particle-size diamond-coated grinding belt of the present invention uses fine-particle alumina micro powder combined with thickener bentonite or nano-silica to form an anti-settling system, which can significantly improve the anti-settling effect of the slurry, and the diamond particles have fixed support positions in the coating system.

[0026] 5. The large-diameter diamond-coated abrasive belt of this invention uses a high-hardness resin to improve the overall coating adhesion and tensile strength, ensuring that the diamond particles and cutting edges are still exposed, while also serving as a secondary reinforcement of the coating.

[0027] 6. The preparation process of the large-diameter diamond-coated abrasive belt of the present invention includes three-zone heating in the drying tunnel during the rewinding process, with temperatures of 80℃-120℃-90℃ respectively, so that the resin initially coats the particles and prevents adhesion during product shaping and curing; the curing adopts a gradient curing process, first curing to enhance the interfacial bonding, and then raising the temperature to fully cure, thereby improving the heat resistance of the resin. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a stereoscopic photograph of the large-diameter diamond-coated abrasive belt of the present invention under a high-power microscope. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0031] A large-particle-diameter diamond-coated abrasive belt comprises, from the inside out: a flexible substrate, a diamond coating, and an adhesive layer.

[0032] Preferably, the flexible substrate is a PET tape-based or polyimide high-temperature resistant film substrate with a thickness of 75~125μm, including but not limited to 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, and 125μm, and preferably a pre-coated or corona-treated substrate.

[0033] The pre-coated substrate with corona treatment is treated by the supplier. To improve the adhesion of the abrasive coating, a substrate with pre-coating or corona treatment is selected for coating production. To improve the coating adhesion and sustainable high grinding capability of diamond grinding belts, a PET substrate with a pre-coated surface is selected as the coating substrate. Compared with ordinary PET substrates, this has good solvent-based slurry spreading performance, which can greatly enhance the bonding ability between the coating and PET.

[0034] Preferably, the diamond coating comprises the following components in parts by weight: 30-55 parts of large-particle-size diamond micro powder (including but not limited to 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, and 55 parts), 5-10 parts of alumina micro powder (including but not limited to 5 parts, 8 parts, and 10 parts), 3-10 parts of thickener (including but not limited to 3 parts, 6 parts, 9 parts, and 10 parts), and 25-62 parts of polyurethane resin with a low TG point (glass transition temperature) (≤30°C) (including but not limited to 25 parts, 28 parts, 32 parts, 36 parts, 40 parts, 44 parts, 48 ​​parts, 52 parts, 56 parts, 60 parts, and 62 parts).

[0035] The diamond coating uses a slurry composed of a base resin and large-particle-size diamond micropowder, ensuring a high diamond micropowder content. This high powder content increases the density of diamond particles arranged in a single layer within the coating, while simultaneously maintaining sufficient surface area of ​​the diamond particles exposed outside the adhesive layer, laying the foundation for improved cutting force in subsequent applications.

[0036] The base resin for the diamond coating is a low-TG polyurethane resin, which increases the toughness of the coating and prevents brittle fracture during use, thus preventing sand shedding.

[0037] Preferably, the particle size of the large-particle-size diamond micro powder is 40~200μm, including but not limited to 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, and 200μm, and more preferably 45~100μm.

[0038] Preferably, the thickness of the diamond coating is ±10μm of the particle size of the large-diameter diamond powder, and the thickness of the diamond coating varies depending on the size of the diamond particles.

[0039] Preferably, the large-diameter diamond is one or a combination of resin-bonded diamond and metal-bonded diamond.

[0040] Preferably, the alumina micro powder has a particle size of 3~6μm, including but not limited to 3μm, 4μm, 5μm, and 6μm. Adding fine-grained alumina micro powder acts as a reinforcing phase, increasing fixation sites in the coating and filling the spaces between diamond particles in the matrix resin with solids, thus enhancing the anti-collapse resistance of the effective grinding particles during product use. The fine-grained alumina micro powder fills resin microcracks and simultaneously forms a mechanical interlock with the larger diamond micro powder particles, improving adhesion. The selection of small-grained alumina micro powder serves two purposes: firstly, it does not affect the exposure of the grinding edge of the large diamond particles, and secondly, it provides a semi-fixing effect.

[0041] Preferably, the thickener is one or a combination of bentonite, nano-silica, cellulose, fatty alcohol, fatty acid, ether, and associative polyurethane thickeners; preferably bentonite or nano-silica, by adding bentonite or nano-silica, thickening substances are introduced into the slurry to increase the viscosity of the slurry, while preventing large diamond particles from settling during the slurry circulation process.

[0042] By using fine-grained alumina powder combined with thickeners such as bentonite or nano-silica to form an anti-settling system, the anti-settling effect of the slurry can be significantly improved, and the diamond particles have fixed support positions in the coating system.

[0043] Preferably, the polyurethane resin with a low TG point is a polyurethane resin with a TG ≤ 30℃, and the polyurethane resin with a low TG point can be purchased directly from the market.

[0044] Preferably, the adhesive layer comprises the following components by weight: 10-40 parts of epoxy resin (including but not limited to 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, and 40 parts), and 60-90 parts of polyurethane resin with a high TG point (≥55℃) (including but not limited to 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, and 90 parts); the adhesive layer resin uses a high-hardness resin blend to improve the adhesion and tensile strength of the overall coating.

[0045] Preferably, the thickness of the adhesive layer is 3~10μm, including but not limited to 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, and preferably 5~7μm; while ensuring that the diamond particles still have exposed cutting edges, it also serves as a secondary reinforcement coating.

[0046] Preferably, the polyurethane resin with a high TG point is a polyurethane resin with a TG ≥ 55℃, and the polyurethane resin with a high TG point can be purchased directly from the market.

[0047] Preferably, the epoxy equivalent of the epoxy resin is 1000~3000g / eq, including but not limited to 1000g / eq, 1000g / eq, 1500g / eq, 2000g / eq, 2500g / eq, and 3000g / eq.

[0048] The above-mentioned process for preparing large-particle-size diamond-coated abrasive belts includes the following steps: Step S1: Prepare the coating solution for preparing the diamond coating; Step S2: Prepare the adhesive liquid for preparing the adhesive layer; Step S3: Apply the coating liquid onto the substrate to form a diamond coating; Step S4: Apply the adhesive liquid onto the diamond coating; Step S5: Rewind and cure the coated product; Step S6: Cut, package, and test the cured product.

[0049] Preferably, the method for preparing the coating liquid for preparing the diamond coating in step S1 is as follows: a mixed adhesive of low TG point polyurethane resin is added to large-particle-size diamond micro powder in a certain proportion, a mixed solvent is added, alumina micro powder and thickener are added in a certain proportion, and the mixture is fully dispersed to obtain a slurry. A polyurethane curing agent is added to the slurry to obtain the coating liquid.

[0050] Preferably, the solid content of the mixed adhesive of low TG point polyurethane resin in step S1 is 25% to 50%, including but not limited to 25%, 30%, 35%, 40%, 45%, and 50%.

[0051] Preferably, the method for preparing the adhesive liquid for preparing the adhesive layer in step S2 is as follows: take a mixture of polyurethane resin and epoxy resin with a high TG point in proportion, add a mixed solvent, add a polyurethane curing agent, and disperse evenly to obtain the adhesive liquid.

[0052] Preferably, the solid content of the mixed adhesive of high TG point polyurethane resin and epoxy resin in step S2 is 25% to 50%, including but not limited to 25%, 30%, 35%, 40%, 45%, and 50%.

[0053] Preferably, the mixed solvent in steps S1 and S2 is a mixture of butanone, ethyl acetate and toluene in a mass ratio of 1:1~2:1~2, and the mass ratio includes, but is not limited to, 1:1:1, 1:1:2, 1:2:1 and 1:2:2.

[0054] Preferably, in step S5, during the rewinding process of the coating machine, the drying tunnel is heated in three zones at temperatures of 80℃-120℃-90℃ respectively, so that the resin initially coats the particles and prevents them from sticking together during product setting and curing.

[0055] Preferably, the curing process in step S5 adopts a gradient curing process. First, it is cured at 35~80℃ (including but not limited to 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃) for 1~24h (including but not limited to 1h, 5h, 10h, 15h, 20h, 24h) to enhance the interfacial bonding. Then, it is cured at 60~100℃ (including but not limited to 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃) for 12~48h (including but not limited to 12h, 24h, 36h, 48h) to fully cure and improve the heat resistance of the resin.

[0056] Example 1 A process for preparing large-particle-size diamond-coated abrasive belts includes the following steps: 1. Take 500g of artificial single-crystal diamond micro powder with D50=60μm and 50g of alumina micro powder with D50=5μm, and set aside. 2. Add 1200g of mixed adhesive A with a solid content of 25% to the diamond micro powder, then add 700g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:1:1, add 50g of alumina micro powder and 50g of bentonite thickener, and disperse thoroughly by ball mill or ultrasonic disperser to obtain slurry. Add 100g of polyurethane curing agent to the slurry to obtain coating liquid. Among them, the mixed adhesive A is a mixture of two low-TG point polyurethane resins with different TG points, namely, TG=7℃ polyurethane resin and TG=10℃ polyurethane resin, in a mass ratio of 3:1. 3. Take 1000g of mixed adhesive B with a solid content of 25%, add 500g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:1:1, add 120g of polyurethane curing agent, and disperse evenly by high-speed stirring to obtain the adhesive liquid. The mixed adhesive B is obtained by mixing polyurethane resin (high TG point polyurethane resin) with TG=70℃ and epoxy resin with epoxy equivalent of 2500g / eq at a mass ratio of 4:1. 4. The coating liquid is processed by a coating machine to form a coating with a thickness of 65μm on a 75μm PET substrate. Its microstructure consists of a single layer of diamond particles with gaps between them. 5. The coating after step 4 is re-processed by a coating machine, and an adhesive layer with a thickness of 5μm is applied on the coating containing diamond abrasive. 6. After the adhesive coating process is completed, the product is rewound by the coating machine, and the drying tunnel is heated in three zones at temperatures of 80℃-120℃-90℃ respectively. 7. Place the product in a curing oven to cure, first at 80℃ for 24 hours, then at 100℃ for 48 hours; 8. Cut, package, and test the product after curing.

[0057] Example 2 A process for preparing large-particle-size diamond-coated abrasive belts includes the following steps: 1. Take 500g of synthetic single-crystal diamond micro powder with D50=100μm and 75g of alumina micro powder with D50=5μm, and set aside. 2. Add 1500g of mixed adhesive A with a solid content of 25% to the diamond micro powder, then add 700g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:1:2, add 75g of alumina micro powder, add 70g of bentonite thickener, and disperse thoroughly by ball mill or ultrasonic disperser to obtain slurry. Add 120g of polyurethane curing agent to the slurry to obtain coating liquid. Among them, the mixed adhesive A is a mixture of two low TG point polyurethane resins with different TG points, namely TG=-15℃ polyurethane resin and TG=13℃ polyurethane resin, in a mass ratio of 3:1. 3. Take 1000g of mixed adhesive B with a solid content of 25%, add 500g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:1:2, add 150g of polyurethane curing agent, and disperse evenly by high-speed stirring to obtain the adhesive liquid. The mixed adhesive B is obtained by mixing polyurethane resin with TG=67℃ (high TG point polyurethane resin) and epoxy resin with epoxy equivalent of 3000g / eq at a mass ratio of 4:1. 4. The coating liquid is processed by a coating machine to form a coating with a thickness of 96μm on a 125μm PET substrate. Its microstructure consists of a single layer of diamond particles with gaps between them. 5. The coating after step 4 is re-processed by the coating machine, and an adhesive layer with a thickness of 7μm is applied on the coating containing diamond abrasive. 6. After the adhesive coating process is completed, the product is rewound by the coating machine, and the drying tunnel is heated in three zones at temperatures of 80℃-120℃-90℃ respectively. 7. Place the product in a curing oven to cure, first at 80℃ for 24 hours, then at 100℃ for 48 hours; 8. Cut, package, and test the product after curing.

[0058] Example 3 A process for preparing large-particle-size diamond-coated abrasive belts includes the following steps: 1. Take 500g of synthetic single-crystal diamond powder with D50=45μm and 50g of alumina powder with D50=5μm, and set aside. 2. Add 1000g of mixed adhesive A with a solid content of 25% to diamond micro powder, then add 500g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:2:1, add 50g of alumina micro powder, add 30g of bentonite thickener, and disperse thoroughly by ball mill or ultrasonic disperser to obtain slurry. Add 100g of polyurethane curing agent to slurry to obtain coating liquid. Among them, the mixed adhesive A is obtained by mixing two low TG point polyurethane resins with different TG points, namely TG=-15℃ polyurethane resin and TG=10℃ polyurethane resin, in a mass ratio of 3:1. 3. Take 1000g of mixed adhesive B with a solid content of 25%, add 500g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:2:1, add 100g of polyurethane curing agent, and disperse evenly by high-speed stirring to obtain the adhesive liquid. The mixed adhesive B is obtained by mixing polyurethane resin with TG=67℃ (high TG point polyurethane resin) and epoxy resin with epoxy equivalent of 2100g / eq at a mass ratio of 4:1. 4. The coating liquid is processed by a coating machine to form a coating with a thickness of 49μm on a 75μm PET substrate. Its microstructure consists of a single layer of diamond particles with gaps between them. 5. The coating after step 4 is re-processed by the coating machine, and an adhesive layer with a thickness of 3μm is applied on the coating containing diamond abrasive. 6. After the adhesive coating process is completed, the product is rewound by the coating machine, and the drying tunnel is heated in three zones at temperatures of 80℃-120℃-90℃ respectively. 7. Place the product in a curing oven to cure, first at 80℃ for 24 hours, then at 100℃ for 48 hours; 8. Cut, package, and test the product after curing.

[0059] Example 4 A process for preparing large-particle-size diamond-coated abrasive belts includes the following steps: 1. Take 500g of artificial single-crystal diamond micro powder with D50=60μm and 50g of alumina micro powder with D50=5μm, and set aside. 2. Add 1200g of mixed adhesive A with a solid content of 25% to the diamond micro powder, then add 700g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:1:1, add 50g of alumina micro powder, add 50g of nano-silica thickener, and disperse thoroughly by ball mill or ultrasonic disperser to obtain slurry. Add 100g of polyurethane curing agent to the slurry to obtain coating liquid. Among them, the mixed adhesive A is a mixture of two low-TG point polyurethane resins with different TG points, namely, TG=7℃ polyurethane resin and TG=10℃ polyurethane resin, in a mass ratio of 3:1. 3. Take 1000g of mixed adhesive B with a solid content of 25%, add 500g of a mixed solvent of butanone, ethyl acetate and toluene in a mass ratio of 1:1:1, add 120g of polyurethane curing agent, and disperse evenly by high-speed stirring to obtain the adhesive liquid. The mixed adhesive B is obtained by mixing polyurethane resin (high TG point polyurethane resin) with TG=70℃ and epoxy resin with epoxy equivalent of 2500g / eq at a mass ratio of 4:1. 4. The coating liquid is processed by a coating machine to form a coating with a thickness of 65μm on a 75μm PET substrate. Its microstructure consists of a single layer of diamond particles with gaps between them. 5. The coating after step 4 is re-processed by a coating machine, and an adhesive layer with a thickness of 5μm is applied on the coating containing diamond abrasive. 6. After the adhesive coating process is completed, the product is rewound by the coating machine, and the drying tunnel is heated in three zones at temperatures of 80℃-120℃-90℃ respectively. 7. Place the product in a curing oven to cure, first at 80℃ for 24 hours, then at 100℃ for 48 hours; 8. Cut, package, and test the product after curing.

[0060] Comparative Example 1 The difference between this comparative example and Example 1 is that the coating process is omitted, that is, the grinding belt product does not contain a coating layer.

[0061] Comparative Example 2 The difference between this comparative example and Example 1 is that the coating liquid does not contain alumina powder, that is, the diamond coating of the grinding belt product does not contain alumina powder.

[0062] Comparative Example 3 The difference between this comparative example and Example 1 is that the coating liquid does not contain bentonite thickener, that is, the diamond coating of the grinding belt product does not contain bentonite thickener.

[0063] Comparative Example 4 The difference between this comparative example and Example 1 is that the curing is carried out at a constant temperature of 80°C for 48 hours.

[0064] Experimental example: 1. Adhesion tests were conducted on the abrasive belt products prepared in Examples 1-4 and Comparative Examples 1-4. The adhesion of the coating in Examples 1-4 was significantly enhanced by the scribing method, and there was no obvious exposure of the substrate after scribing.

[0065] 2. Cutting force tests were conducted on the grinding belt products prepared in Examples 1-4 and Comparative Examples 1-4. The cutting force of the grinding belt products prepared in Examples 1-4 was significantly improved and the continuous performance was enhanced by grinding the ceramic inserts with a four-corner pressure grinding machine.

[0066] 3. The abrasive shedding of the abrasive belt products prepared in Examples 1-4 and Comparative Examples 1-4 was tested. The ceramic insert was ground by a four-corner pressure grinding machine, and the presence of diamond particles on the surface of the abrasive paper was observed after 20 minutes of continuous grinding. The abrasive shedding of the abrasive belt products prepared in Examples 1-4 was significantly improved.

[0067] IV. The service life of the abrasive paper was tested on the abrasive belt products prepared in Examples 1-4 and Comparative Examples 1-4. The ceramic insert was ground by a four-corner pressure abrasive machine, and the peeling of the coating on the surface of the abrasive paper was observed after grinding for 10 minutes per cycle. The service life of the abrasive belt products prepared in Examples 1-4 was significantly improved.

[0068] V. The test results of the abrasive belt products prepared in Examples 1-4 and Comparative Examples 1-4 are shown in Table 1.

[0069] Table 1. Test results of the abrasive belt products prepared in Examples 1-4 and Comparative Examples 1-4

[0070] As shown in the table above, multi-layer coating can significantly improve the coating adhesion and cutting force of large-particle diamond abrasive belts during use. Furthermore, the multi-layer coating process ensures a high diamond powder content, allowing sufficient diamond particles to be used in the grinding process, enhancing the product's cutting force and continuous performance. Adding fine-grained alumina powder as a reinforcing phase increases the number of solidification sites in the coating, enhancing the anti-collapse resistance of the effective abrasive particles during use and improving service life. The fine-grained alumina powder combined with thickeners such as bentonite or nano-silica forms an anti-settling system, significantly improving the slurry's anti-settling effect and effectively enhancing the product's continuous cutting ability. The rewinding process and gradient curing process first strengthen the interfacial bonding through curing, then fully cures by raising the temperature, increasing the resin's density and thus enhancing the product's adhesion and cutting force.

Claims

1. A large particle size diamond coated abrasive belt characterized in that, From inside to outside, it includes flexible substrate, diamond coating and glue coating in turn; The diamond coating includes the following components by weight: 30-55 parts of large particle size diamond powder, 5-10 parts of alumina powder, 3-10 parts of thickening agent, 25-62 parts of low TG point polyurethane resin; The glue coating includes the following components by weight: 10-40 parts of epoxy resin, 60-90 parts of high TG point polyurethane resin.

2. The large particle size diamond coated abrasive belt of claim 1, wherein, The flexible substrate is PET tape base or polyimide high temperature resistant film substrate with a thickness of 75-125 μm.

3. The large particle size diamond coated abrasive belt of claim 1, wherein, The particle size of the large particle size diamond powder is 40-200 μm, and the thickness of the diamond coating is the particle size of the large particle size diamond powder ±10 μm.

4. The large particle size diamond coated abrasive belt of claim 1, wherein, At least one of the following technical features is included: (1) The particle size of the alumina powder is 3-6 μm; (2) The thickening agent is one or a combination of bentonite, nano white carbon black, cellulose, fatty alcohol, fatty acid, ether and associated polyurethane; (3) The low TG point polyurethane resin is a polyurethane resin with TG≤30℃.

5. The large particle size diamond coated abrasive belt of claim 1 wherein, The thickness of the glue coating is 3-10 μm.

6. The large particle size diamond coated abrasive belt of claim 1, wherein, At least one of the following technical features is included: (1) The high TG point polyurethane resin is a polyurethane resin with TG≥55℃; (2) The epoxy equivalent weight of the epoxy resin is 1000-3000 g / eq.

7. The process for preparing a large particle size diamond coated abrasive belt according to any one of claims 1 to 6, wherein The following steps are included: Step S1, preparing coating liquid for preparing diamond coating; Step S2, preparing glue coating liquid for preparing glue coating; Step S3, coating the coating liquid on the substrate to form the diamond coating; Step S4, coating the glue coating liquid on the diamond coating; Step S5, rewinding and curing the product after gluing.

8. The process for preparing a large particle size diamond coated abrasive belt according to claim 7, wherein, At least one of the following technical features is included: (1) The method for preparing the coating liquid for preparing the diamond coating in step S1 is as follows: adding a mixed adhesive of low TG point polyurethane resin to the large particle size diamond powder in proportion, adding a mixed solvent, adding alumina powder and thickening agent in proportion, and fully dispersing to obtain slurry, and then adding polyurethane curing agent to the slurry to obtain the coating liquid; (2) The method for preparing the glue coating liquid for preparing the glue coating in step S2 is as follows: taking a mixed adhesive of high TG point polyurethane resin and epoxy resin in proportion, adding a mixed solvent, adding polyurethane curing agent, and uniformly dispersing to obtain the glue coating liquid.

9. The process for preparing a large particle size diamond coated abrasive belt according to claim 7, wherein, In the drying channel three-zone heating in the rewinding process of the coating machine in step S5, gradient curing process is adopted, i.e., first curing at 35-80℃ for 1-24h, and then curing at 60-100℃ for 12-48h.

10. The application of the preparation process of the large particle size diamond coated abrasive belt according to any one of claims 1-6 or the large particle size diamond coated abrasive belt according to any one of claims 7-9 in the preparation of large particle size diamond coated abrasive belt and large particle size diamond coated abrasive sheet.

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