A light-cured resin adhesive for coated abrasive tools and a method for preparing and using the same

Abstract

The present application relates to the technical field of light-cured glue, and particularly relates to a light-cured resin rubberizing agent for coated abrasive tools and a preparation method and use method thereof, wherein the preparation raw materials include, by weight, 60-75 parts of oligomer, 20-45 parts of functional monomer, 4-6 parts of photoinitiator and 0.1-1.5 parts of auxiliary agent. The light-cured resin rubberizing agent provided by the present application can significantly reduce energy consumption, improve the production environment, save site space and improve production efficiency while meeting the performance requirements of the rubberizing agent for coated abrasive tools.

Description

Technical Field

[0001] This invention relates to the field of photocurable adhesive technology, and in particular to a photocurable resin coating for coating abrasives, its preparation method, and its application method. Background Technology

[0002] Coated abrasives are grinding tools made by fixing abrasive particles onto flexible substrates such as paper, cloth, or film using adhesives such as resin. Common forms include sandpaper, abrasive cloth, abrasive belts, and abrasive discs. Often referred to as the "teeth of modern industry," they are indispensable surface treatment and precision machining tools in fields such as metal processing, woodworking, automotive manufacturing, aerospace, 3C electronics, and architectural decoration. Their main production processes include: primer application, abrasive coating, topcoat application, drying, winding, and conversion.

[0003] The primer process involves uniformly applying a first layer of adhesive to the substrate surface. Abrasive grains are then embedded into the primer layer using electrostatic or gravity-based abrasive embedding methods. Pre-drying allows the abrasive grains to achieve initial positioning and retention. The primer directly determines the initial abrasive retention strength, abrasive grain distribution uniformity, and interface durability of the product.

[0004] The bonding process involves applying a second adhesive layer while the base coat is semi-cured. This adhesive needs to penetrate to the bottom of the abrasive to improve its resistance to peeling. At the same time, the thickness and leveling of the bonding layer are used to adjust the abrasive's cutting edge height and uniformity, balancing the cutting sharpness and the substrate's support strength. This is a core step that determines the product's service life and grinding performance.

[0005] Currently, the mainstream primer and topcoat systems used in the coated abrasive industry include epoxy resin, polyurethane resin, urea-formaldehyde resin, and phenolic resin. For example, Chinese invention patent CN105440874B discloses an adhesive for coated abrasives, whose raw materials include water-soluble phenolic resin, modified functional resin, and filler. These systems almost always require prolonged heating at 100-140°C, either directly or with the aid of a curing agent, to achieve complete curing. Specifically, after the base coat is applied, it needs to be pre-dried for 15 to 30 minutes to allow the solvent to evaporate and the base coat to partially cure, thus fixing the vertical position of the sand particles. The thickness of the top coat is usually 2 to 3 times that of the base coat. To ensure that the abrasive can withstand extrusion and impact during grinding, the top coat system needs to have high mechanical strength. Therefore, it needs to be dried continuously in a high-temperature environment of 100 to 140°C for 3 to 6 hours (main drying). Summary of the Invention

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides a photocurable resin coating for coating abrasives, wherein the raw materials for preparation include, by weight, 60-75 parts of oligomer, 20-45 parts of functional monomer, 4-6 parts of photoinitiator, and 0.1-1.5 parts of additives.

[0007] In some embodiments, the oligomer includes at least one of phenolic epoxy acrylate, polyurethane acrylate, and bisphenol A epoxy acrylate.

[0008] Optionally, the oligomer satisfies at least one of the following characteristics: (1) The oligomers include phenolic epoxy acrylate and bisphenol A epoxy acrylate, wherein the mass ratio of phenolic epoxy acrylate to bisphenol A epoxy acrylate is (35~50):(20~25); it can be listed as 35:20, 45:25, 50:20, or any value in the range of (35~50):(20~25); (2) The oligomers include phenolic epoxy acrylate and polyurethane acrylate, wherein the mass ratio of phenolic epoxy acrylate to polyurethane acrylate is (40~50):(25~35); it can be listed as 40:25, 45:30, 50:35, or any value in the range of (40~50):(25~35).

[0009] Phenolic epoxy acrylates possess a highly rigid benzene ring structure and multifunctional properties, providing high hardness and high heat resistance to the adhesive layer. However, when used alone, the crosslinked network is too dense, resulting in high brittleness and poor impact resistance. This application achieves a "rigid skeleton + flexible buffer" network structure by compounding phenolic epoxy acrylates with bisphenol A type epoxy acrylates / polyurethane acrylates, thus avoiding excessive embrittlement and achieving a balance between hardness and heat resistance.

[0010] In some embodiments, the polyurethane acrylate comprises difunctional polyurethane acrylate and nonfunctional polyurethane acrylate, wherein the mass ratio of the difunctional polyurethane acrylate to the nonfunctional polyurethane acrylate is (5~15):(15~25); examples include 5:15, 10:20, 10:25, or any value within the range of (5~15):(15~25).

[0011] In some embodiments, the functional monomer includes at least one of trimethylolpropane triacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and isobornyl acrylate.

[0012] Optionally, the functional unit satisfies at least one of the following characteristics: (1) The functional monomers include trimethylolpropane triacrylate and tripropylene glycol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to tripropylene glycol diacrylate is (10~20):(5~15); it can be listed as 10:5, 15:10, 20:15, or any value within the range of (10~20):(5~15); (2) The functional monomers include trimethylolpropane triacrylate and 1,6-hexanediol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to 1,6-hexanediol diacrylate is (5~15):(5~15); it can be listed as 10:10, 5:10, 15:10, or any value within the range of (5~15):(5~15); (3) The functional monomers include 1,6-hexanediol diacrylate, isobornyl acrylate and tripropylene glycol diacrylate, wherein the mass ratio of 1,6-hexanediol diacrylate, isobornyl acrylate and tripropylene glycol diacrylate is (15~25):(10~20):(5~15); it can be listed as 20:15:10, 15:10:10, 25:20:15, or any value in the range of (15~25):(10~20):(5~15).

[0013] In some embodiments, the photoinitiator includes at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

[0014] Optionally, the photoinitiator comprises diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, wherein the mass ratio of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide to phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is (1~5):(1~5). Examples include 3:2, 2:3, 4:5, or any value within the range of (1~5):(1~5).

[0015] In some embodiments, the additives include at least one of defoamers and leveling agents.

[0016] Optionally, the additives include defoamers and leveling agents.

[0017] In some embodiments, the raw materials for preparation also include solvents.

[0018] Optionally, the solvent includes at least one of ethyl acetate and butyl acetate.

[0019] In some embodiments, the solvent is ethyl acetate and butyl acetate.

[0020] When it is necessary to further reduce the viscosity of the photocurable resin for coated abrasives to meet the requirements of fine-grained products or thin-coating processes, ethyl acetate, butyl acetate, or a mixture thereof can be added to adjust the viscosity to the target range.

[0021] The second aspect of the present invention provides a method for preparing a photocurable resin coating for coated abrasives, comprising at least the following steps: mixing the raw materials uniformly to obtain the photocurable resin coating for coated abrasives.

[0022] A third aspect of the present invention provides a method for applying a light-curing resin coating for abrasives, comprising at least the following steps: S1. Obtain the coated abrasive semi-finished product; S2. The coated abrasive is uniformly coated with a UV-curable resin and then heat-treated at 50-80°C for 5-180 seconds before being cured with UV-LED gradient. The coated abrasive is then obtained through a winding and conversion process.

[0023] The solvent in this application only requires a short-term low-temperature heat treatment (50~80℃, 5~180s) after the adhesive is applied, which can achieve solvent evaporation and provide driving force for the adhesive to sink, penetrate and level.

[0024] In some embodiments, the coating method is selected from two-roll coating, three-roll coating, doctor blade coating, or microgravure coating.

[0025] In some embodiments, the UV-LED gradient curing employs gradient energy output, which includes at least two levels of energy output, each level having an intensity 1.05 to 3 times that of the previous level, and each level having an exposure time between 0.5 and 2 seconds.

[0026] Existing lamination systems such as epoxy resin, polyurethane resin, urea-formaldehyde resin, and phenolic resin, and their required high-temperature, long-term curing processes, have the following prominent problems: High VOC emissions: The adhesive contains a large amount of organic solvents. During the high-temperature drying process, the solvents evaporate and produce a large amount of volatile organic compounds, which puts great pressure on the exhaust gas treatment device and makes it difficult to meet increasingly stringent environmental protection requirements. Substrate thermal damage: Continuous and prolonged high-temperature treatment can cause irreversible shrinkage and embrittlement of substrates such as paper, cloth, film, and especially heat-sensitive film, which greatly limits the use of some high-performance substrates. High energy consumption and poor production environment: Long-term high-temperature drying requires a large amount of energy such as natural gas, and the production workshop is hot and smelly, and the working environment for workers is harsh. Low efficiency and large footprint: The high-temperature curing time of several hours has become a bottleneck limiting the production efficiency of the entire production line. The only way to improve efficiency is to increase the volume of the curing oven, making it difficult to achieve centralized and high-efficiency production. However, this application uses UV-LED gradient curing of the adhesive, which only requires a few seconds of curing time and does not require high temperature. The gradient energy causes the surface layer to cure slowly, reducing surface shrinkage stress; the deep layers gradually cross-link, avoiding stress concentration and forming a uniform cross-linked network.

[0027] In some embodiments, the UV-LED gradient curing employs a continuous UV-LED curing device.

[0028] In some embodiments, S1 includes: Primer: Apply primer evenly to the sand-coated surface of the substrate; Sand embedding: Under the action of gravity or electric field force, one end of the abrasive is embedded into the base adhesive; Pre-drying: The sand-coated product is pre-dried using a hot air drying oven to obtain a coated abrasive semi-finished product.

[0029] Beneficial effects: (1) The present invention selects specific oligomers, functional monomers and photoinitiators and controls their dosage to construct a crosslinked network with high hardness, high heat resistance and moderate toughness, which solves the problems of insufficient hardness, poor heat resistance and inability to meet the requirements of heavy-duty grinding of traditional photocurable adhesives, as well as poor tensile strength of abrasives.

[0030] (2) When it is necessary to further reduce the viscosity of the photocurable resin for coated abrasives to meet the requirements of fine-grained products or thin-coating processes, ethyl acetate, butyl acetate or their mixed solvents can be added to avoid performance degradation, uncontrollability and cost increase caused by the large amount of functional monomers used due to the low viscosity requirement of the coating.

[0031] (3) The photocurable resin coating of the present invention only requires short-term low-temperature heat treatment after coating to achieve solvent evaporation and provide driving force for the sinking, penetration and leveling of the adhesive.

[0032] (4) The photocurable resin coating of the present invention can be rapidly cured within seconds through UV-LED gradient curing process, completely replacing the high-temperature long-time drying process of the coating layer for several hours in the traditional coated abrasive production. It fundamentally solves the problems of large VOC emissions, substrate thermal damage, high energy consumption and low production efficiency in the traditional system. Under the premise of ensuring the service life and grinding performance of coated abrasive, it significantly reduces production energy consumption, shortens the production cycle, and is more environmentally friendly and energy-saving. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, and to fully demonstrate the technical solutions and wide applicability of this invention, the following embodiments are provided to further illustrate this invention in three typical application scenarios: fine-grit sandpaper (requiring high strength, low viscosity, solvent-based viscosity adjustment), coarse-grit abrasive belts (requiring thick coating, high strength and high toughness, solvent-free), and soft film sandpaper (using a heat-sensitive film as the substrate, requiring low temperature and no heat accumulation). It should be understood that the specific embodiments described herein are only for explaining this invention and are not intended to limit it. Experimental methods not specifying specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the solvent in the solutions involved in this invention is water; the room temperature is 25°C; and all raw materials, consumables, and equipment used are commercially available.

[0034] The raw material details for each embodiment and comparative example are shown in Table 1 below.

[0035] Table 1

[0036] Example 1 The first aspect of this example provides a light-curing resin coating for coated abrasives (P500 sandpaper), the raw materials of which, by weight, include: 70 parts of oligomer, 25 parts of functional monomer, 5 parts of photoinitiator, and 1.125 parts of additives.

[0037] The oligomers are phenolic epoxy acrylate and bisphenol A type epoxy acrylate, and the mass ratio of phenolic epoxy acrylate to bisphenol A type epoxy acrylate is 50:20.

[0038] The functional monomers are trimethylolpropane triacrylate and tripropylene glycol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to tripropylene glycol diacrylate is 15:10.

[0039] The photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and the mass ratio of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide to phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is 3:2.

[0040] The additives are defoamer HY-900 and leveling agent BYK-333, and the mass ratio of HY-900 to BYK-333 is 5:4.

[0041] The raw materials for preparation also include a solvent, which is ethyl acetate and butyl acetate in a mass ratio of 1:1.

[0042] The second aspect of this example provides a method for preparing a photocurable resin coating for coated abrasives, comprising the following steps: mixing oligomers, functional monomers, photoinitiators, and additives uniformly to obtain a mixed resin; adding solvent to the mixed resin to adjust the system viscosity to 60±25 cps; and controlling the solid content to 75%~85% to obtain the photocurable resin coating for coated abrasives.

[0043] The third aspect of this example provides a method for applying a light-curing resin coating to abrasives, including the following steps: S1. Obtain P500 sandpaper semi-finished product; S2. Using a two-roll coating method, the UV-curable resin for coating abrasive is uniformly coated onto the P500 sandpaper semi-finished product. After heat treatment at 85°C for 180s, UV-LED gradient curing is performed, followed by winding and conversion processes to obtain the coated abrasive.

[0044] S1 includes: Primer: Mix epoxy resin and epoxy curing agent evenly at a ratio of 1:0.7 and adjust the viscosity as needed. Apply the primer evenly to the sand-coated surface of the substrate. The primer application amount is 10±2.5g / m². 2 ; Sand planting: The substrate is processed by an electrostatic sand planting device, and under the action of electrostatic force, one end of the abrasive is embedded in the base adhesive; Pre-drying: The sand-coated product is pre-dried using a hot air drying oven at a temperature of 100±15℃ for 30±15 minutes to obtain P500 sandpaper semi-finished product.

[0045] The coating thickness is 25 μm.

[0046] The UV-LED gradient curing process involves passing the heat-treated P500 sandpaper semi-finished product through 5 groups of equally spaced UV-LED lamps for gradient curing, with each group having an exposure time of 1 second.

[0047] The peak power of the UV-LED lamp is 400 mw / cm². 2 The output power of the five groups of equally spaced UV-LED lamps is set to 75%, 80%, 85%, 90%, and 95% of their peak power, respectively.

[0048] Example 2 The first aspect of this example provides a photocurable resin coating for coated abrasives (P80 abrasive belts), the raw materials of which, by weight, include: 75 parts of oligomer, 20 parts of functional monomer, 5 parts of photoinitiator, and 1.5 parts of additives.

[0049] The oligomers are phenolic epoxy acrylate and polyurethane acrylate, and the mass ratio of phenolic epoxy acrylate to polyurethane acrylate is 45:30.

[0050] The polyurethane acrylate is a difunctional polyurethane acrylate and a nonfunctional polyurethane acrylate, and the mass ratio of the difunctional polyurethane acrylate to the nonfunctional polyurethane acrylate is 10:20.

[0051] The functional monomers are trimethylolpropane triacrylate and 1,6-hexanediol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to 1,6-hexanediol diacrylate is 10:10.

[0052] The photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and the mass ratio of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide to phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is 3:2.

[0053] The additives are defoamer HY-900 and leveling agent BYK-333, and the mass ratio of HY-900 to BYK-333 is 2:1.

[0054] The second aspect of this example provides a method for preparing a photocurable resin coating for coated abrasives, comprising the following steps: mixing oligomers, functional monomers, photoinitiators, and additives uniformly, and controlling the temperature (25°C) to control the viscosity of the system at 800±150cps, thereby obtaining the photocurable resin coating for coated abrasives.

[0055] The third aspect of this example provides a method for applying a light-curing resin coating to abrasives, including the following steps: S1. Obtain P80 sanding belt semi-finished product; S2. Using a scraper coating method, the coated abrasive is uniformly coated with UV-curable resin onto the P80 abrasive belt semi-finished product. After heat treatment at 50°C for 7 seconds using an array of infrared heating lamps, UV-LED gradient curing is performed. Subsequently, the product enters the winding and conversion process to obtain the coated abrasive.

[0056] S1 includes: Primer: Mix urea-formaldehyde resin and ammonium chloride at a ratio of 100:1.5 and adjust the viscosity as needed. Apply the primer evenly to the sand-coated surface of the substrate. The primer application amount is 45±8 g / m². 2 ; Sand planting: The substrate is subjected to gravity sand planting equipment, under the action of gravity, one end of the abrasive is embedded into the base adhesive; Pre-drying: The sand-planted product is pre-dried using a hot air drying oven. The drying temperature is 100±15℃ and the drying time is 30±15min, which yields the P80 sand belt semi-finished product.

[0057] The coating thickness is 90 μm.

[0058] The UV-LED gradient curing process involves passing the heat-treated P80 abrasive belt semi-finished product through three sets of equally spaced UV-LED lamps, using a single low-intensity preheating (500 mw / cm²). 2 + Two high-intensity light penetrations (1500 mw / cm) 2 The two-stage curing process (") has a total exposure time of 3 seconds.

[0059] Example 3 The first aspect of this example provides a light-curing resin coating for coated abrasives (P2000 polyurethane soft film sandpaper). By weight, the raw materials include: 60 parts of oligomer, 45 parts of functional monomer, 5 parts of photoinitiator, and 1.333 parts of additives.

[0060] The oligomers are phenolic epoxy acrylate and bisphenol A type epoxy acrylate, and the mass ratio of phenolic epoxy acrylate to bisphenol A type epoxy acrylate is 35:25.

[0061] The functional monomers are 1,6-hexanediol diacrylate, isobornyl acrylate, and tripropylene glycol diacrylate, wherein the mass ratio of 1,6-hexanediol diacrylate, isobornyl acrylate, and tripropylene glycol diacrylate is 20:15:10.

[0062] The photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and the mass ratio of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide to phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is 3:2.

[0063] The additives are defoamer HY-900 and leveling agent BYK-333, and the mass ratio of HY-900 to BYK-333 is 5:3.

[0064] The second aspect of this example provides a method for preparing a photocurable resin coating for coated abrasives, comprising the following steps: mixing oligomers, functional monomers, photoinitiators, and additives uniformly, and controlling the temperature (25°C) to control the viscosity of the system at 400±100cps, thereby obtaining the photocurable resin coating for coated abrasives.

[0065] The third aspect of this example provides a method for applying a light-curing resin coating to abrasives, including the following steps: S1. Obtain P2000 polyurethane soft film sandpaper semi-finished product; S2. Using a micro-gravure coating method, the UV-curable resin coating for the coated abrasive is uniformly applied to the P2000 polyurethane soft film sandpaper semi-finished product. After heat treatment at 50°C for 7 seconds using an array of infrared heating lamps, UV-LED gradient curing is performed. Subsequently, the product enters the winding and conversion process to obtain the coated abrasive.

[0066] S1 includes: Primer: Mix polyester polyol and polyisocyanate in a ratio of 10:2.5 and adjust the viscosity as needed. Apply the primer evenly to the sand-coated surface of the substrate. The primer application amount is 6±1.5g / m². 2 ; Sand planting: The substrate is processed by an electrostatic sand planting device, and under the action of electrostatic force, one end of the abrasive is embedded in the base adhesive; Pre-drying: The sand-coated product is pre-dried using a hot air drying oven. The drying temperature is 80±5℃ and the drying time is 30±15min, resulting in P2000 polyurethane soft film sandpaper semi-finished product.

[0067] The coating thickness is 9 μm.

[0068] The UV-LED gradient curing process involves passing the heat-treated P2000 polyurethane soft film sandpaper semi-finished product through three groups of equally spaced UV-LED lamps for gradient curing, with each group having an exposure time of 1 second.

[0069] The peak power of the UV-LED lamp is 400 mw / cm². 2 The output power of the three groups of equally spaced UV-LED lamps is set to 75%, 85%, and 95% of their peak power, respectively.

[0070] Comparative Example 1 The specific implementation method of this example is the same as that of Example 1, except that, by weight, the raw materials include: 80 parts of oligomer, 20 parts of functional monomer, 5 parts of photoinitiator, and 1.125 parts of additives.

[0071] The oligomers are phenolic epoxy acrylate and bisphenol A type epoxy acrylate, and the mass ratio of phenolic epoxy acrylate to bisphenol A type epoxy acrylate is 60:20.

[0072] The functional monomers are trimethylolpropane triacrylate and tripropylene glycol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to tripropylene glycol diacrylate is 10:10.

[0073] The additives are defoamer HY-900 and leveling agent BYK-333, and the mass ratio of HY-900 to BYK-333 is 5:4. Comparative Example 2 The specific implementation method in this example is the same as in Example 2, except that the method for applying the photocurable resin coating to the abrasive tool does not employ UV-LED gradient curing. Instead, it uses three sets of equally spaced high-power UV-LED modules, applying 2000 mw / cm² of light at a time. 2 High light intensity, gradient-free output, and curing time controlled within 3 seconds.

[0074] Performance testing 1. Appearance of the adhesive layer: Use a magnifying glass to check whether the surface is flat, without cracks or bubbles.

[0075] 2. Pencil hardness of the adhesive layer: Tested using a pencil hardness tester in accordance with GB / T 6739-2006.

[0076] 3. Heat resistance: Place the sample in a 130℃ oven for 1 hour and observe the state of the adhesive layer.

[0077] 4. Curing degree: Moisten a cotton swab with acetone and vigorously rub the surface of the cured adhesive layer back and forth 10 times to observe the dissolution.

[0078] 5. Abrasive holding force (tensile strength): Refer to JB / T 7425-2012, adhere the sample to the tensile testing machine fixture, and test the maximum force value of the abrasive layer peeling off from the substrate.

[0079] 6. Flexibility (bending resistance): Refer to GB / T 1731-1993, bend the sample 180° on shafts of different diameters, and observe the cracking of the adhesive layer.

[0080] 7. Grinding life: Under fixed conditions (2.2kW belt grinder, stainless steel workpiece, grinding pressure 50N), continuous grinding is performed, and the cumulative grinding time is recorded when the belt fails (reduced to 1 / 3 of its initial value).

[0081] 8. Grinding interface temperature: During the grinding process, an infrared thermal imager is used to continuously monitor the temperature of the contact area between the workpiece and the abrasive belt.

[0082] 9. Glass transition temperature (Tg) of the adhesive layer: tested using a dynamic thermomechanical analyzer (DMA).

[0083] The samples prepared in each embodiment and comparative example were tested as described above. The test results for each example are shown in Tables 2 and 3. In the tables, / indicates that the test was not performed.

[0084] Table 2

[0085] Table 3

[0086] As can be seen from the table above, the P500 sandpaper obtained in Comparative Example 1 has low hardness (only B), low tensile strength, poor heat resistance, and incomplete curing of its adhesive layer.

[0087] Comparative Example 2 shows that due to improper UV curing process (excessive energy and no gradient curing), the adhesive layer developed severe internal stress and microcracks, resulting in high brittleness and poor toughness. During grinding, it easily exacerbated heat accumulation, shortening the grinding life by more than 40%. The cross-linking network of the adhesive layer was uneven, reducing the effective Tg.

[0088] The P500 sandpaper obtained in Example 1 of this application exhibits complete adhesive curing with no heat damage to the substrate; the hardness of the coated pencil reaches 2H; there is no significant change after heat treatment at 130℃ for 1 hour; the abrasive holding force is 16.5 N / cm, nearly 20% higher than traditional resin-coated products; compared with traditional phenolic resin coated products (curing at 130℃ for 4-5 hours), the curing time is shortened from hours to seconds, increasing production efficiency by more than 100 times. The product is used for precision grinding of aluminum alloys, achieving a surface finish Ra value <0.4μm.

[0089] The P80 abrasive belt with a composite adhesive layer obtained in Example 2 of this application is strong and tough, and does not crack; the pencil hardness of the composite adhesive layer can reach above 2H; there is no significant change after heat treatment at 130℃ for 1 hour; the abrasive holding force (tensile strength test) is 19.5 N / cm; the grinding life is increased by more than 40% compared with the comparative example; and the VOCs emission during the production process is almost zero.

[0090] In Example 3 of this application, the substrate temperature did not exceed 60°C, completely avoiding the problems of film shrinkage, wrinkling, or melting caused by traditional high-temperature curing. The resulting soft film sandpaper has a uniform abrasive distribution; the pencil hardness of the adhesive layer can reach H, with excellent abrasive encapsulation and an abrasive holding force (tensile strength test) of 14.5 N / cm, making it suitable for high-end applications such as precision polishing (e.g., mobile phone mid-frame).

[0091] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A light-curing resin coating for coating abrasives, characterized in that, The raw materials for preparation, by weight, include: 60-75 parts of oligomer, 20-45 parts of functional monomer, 4-6 parts of photoinitiator, and 0.1-1.5 parts of additives.

2. The photocurable resin coating for coated abrasives according to claim 1, characterized in that, The oligomers include at least one of phenolic epoxy acrylate, polyurethane acrylate, and bisphenol A type epoxy acrylate.

3. The photocurable resin coating for coated abrasives according to claim 2, characterized in that, The oligomer satisfies at least one of the following characteristics: (1) The oligomers include phenolic epoxy acrylate and bisphenol A epoxy acrylate, wherein the mass ratio of phenolic epoxy acrylate to bisphenol A epoxy acrylate is (35~50):(20~25). (2) The oligomers include phenolic epoxy acrylate and polyurethane acrylate, wherein the mass ratio of phenolic epoxy acrylate to polyurethane acrylate is (40~50):(25~35).

4. The photocurable resin coating for coated abrasives according to claim 1, characterized in that, The functional monomers include at least one of trimethylolpropane triacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and isobornyl acrylate.

5. The photocurable resin coating for coated abrasives according to claim 4, characterized in that, The functional unit satisfies at least one of the following characteristics: (1) The functional monomers include trimethylolpropane triacrylate and tripropylene glycol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to tripropylene glycol diacrylate is (10~20):(5~15); (2) The functional monomers include trimethylolpropane triacrylate and 1,6-hexanediol diacrylate, wherein the mass ratio of trimethylolpropane triacrylate to 1,6-hexanediol diacrylate is (5~15):(5~15). (3) The functional monomers include 1,6-hexanediol diacrylate, isobornyl acrylate and tripropylene glycol diacrylate, wherein the mass ratio of 1,6-hexanediol diacrylate, isobornyl acrylate and tripropylene glycol diacrylate is (15~25):(10~20):(5~15).

6. The photocurable resin coating for coated abrasives according to claim 1, characterized in that, The photoinitiator includes at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

7. The photocurable resin coating for coated abrasives according to claim 6, characterized in that, The photoinitiator comprises diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, wherein the mass ratio of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide to phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is (1~5):(1~5).

8. A method for preparing a photocurable resin coating for coated abrasives according to any one of claims 1 to 7, characterized in that, At least the following steps are included: After the raw materials are mixed evenly, the photocurable resin coating for coating abrasives is obtained.

9. A method of using a light-curing resin coating for abrasives according to any one of claims 1 to 7, characterized in that, At least the following steps are included: S1. Obtain the coated abrasive semi-finished product; S2. The coated abrasive is uniformly coated with a UV-curable resin and then heat-treated at 50-80°C for 5-180 seconds before being cured with UV-LED gradient. The coated abrasive is then obtained through a winding and conversion process.

10. The method of use according to claim 9, characterized in that, The UV-LED gradient curing employs gradient energy output, which includes at least two levels of energy output. The intensity of each level of energy output is 1.05 to 3 times that of the previous level, and the exposure time of each level is between 0.5 and 2 seconds.

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