A single-component adhesive for the outer edge of flap wheels, its preparation method and application

Abstract

This invention relates to a single-component flap wheel rim adhesive, its preparation method, and its application, belonging to the field of adhesive preparation technology. The adhesive is composed of the following raw materials by mass percentage, with each component's content meeting the following ranges and the total being 100%: epoxy resin 30%-50%; a microcapsule latent curing agent selected from modified imidazole or modified amine compounds, used in an amount of 5%-15%; epoxy reactive diluent 10%-30%; filler 5%-20%, the filler being one or more of quartz powder, talc powder, or aluminum hydroxide; when multiple fillers are mixed, their total mass percentage is within the above range; leveling agent 1%-5%, the leveling agent being an organosilicon leveling agent; and brightener 1%-3%, the brightener being a high-molecular-weight polyester brightener. This solution solves the pain points of traditional two-component adhesives, which require on-demand mixing and have extremely short operating periods. By removing frictional heat with cooling water, it ensures that the microcapsule latent curing agent selected from modified imidazole or modified amine compounds can be uniformly suspended in micron-sized particles without dissolving.

Description

Technical Field

[0001] This invention relates to the field of adhesive preparation, specifically to a single-component flap wheel rim adhesive, its preparation method, and its application. Background Technology

[0002] As a key tool in industrial processing such as grinding and polishing, the performance of flap wheels directly affects processing efficiency and product quality. The adhesive on the outer edge of the flap wheel needs to have characteristics such as high strength, high adhesion, good penetration, long shelf life, and ease of handling. Traditional flap wheel adhesives are mostly two-component or multi-component products, which need to be mixed and prepared on-site before use. This process is not only time-consuming and labor-intensive, but also prone to mixing errors, resulting in poor bonding effects and even affecting the overall performance and service life of the flap wheel. In particular, the penetration of two-component adhesives is difficult to control precisely, which poses a challenge to the production process and product quality of flap wheels. The defects and shortcomings of existing technologies include: complex operation: Two-component or multi-component adhesives require precise proportioning, which is cumbersome and requires high technical skills from operators. Time wastage: On-site mixing and blending processes are time-consuming, reducing production efficiency; Significant waste: Inaccurate or uneven mixing of adhesives leads to material waste; Difficulty in controlling penetration: The penetration of two-component adhesives is difficult to control precisely, affecting the production process and product quality of flap wheels; Short operating period: Existing two-component adhesives have limited operating periods, making it difficult to meet the needs of long-term production; Low production efficiency: It is difficult to achieve automated production, resulting in high labor demand.

[0003] The information disclosed in the background section above is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a single-component flap wheel outer edge adhesive, its preparation method, and its application, so as to solve the problems mentioned in the background art.

[0005] The technical solution of the present invention is that the adhesive is composed of raw materials in the following mass percentages, and the content of each component satisfies the following ranges and the sum is 100%:

[0006] Epoxy resin 30%-50%;

[0007] A microcapsule latent curing agent, selected from modified imidazole or modified amine compounds, used in an amount of 5%-15%;

[0008] Epoxy reactive diluent 10%-30%;

[0009] The filler is 5%-20%, and the filler is one or more of quartz powder, talc powder or aluminum hydroxide; when it is a mixture of multiple fillers, the total mass percentage is within the above range; the leveling agent is 1%-5%, and the leveling agent is an organosilicon leveling agent; the brightener is 1%-3%, and the brightener is a high molecular weight polyester brightener.

[0010] A method for preparing a single-component flap wheel rim adhesive, employing a multi-stage dispersion process, includes the following steps:

[0011] S1. Base material premixing and wetting: The epoxy resin, the epoxy active diluent, and fillers accounting for 10%-80% of the total mass of the fillers are put into the reactor and stirred at room temperature to allow the fillers to complete the initial wetting and encapsulation in the resin system, forming a basic mixture.

[0012] S2. Low-temperature blending of curing agent: Add the microcapsule latent curing agent selected from modified imidazole or modified amine to the basic mixture obtained in step S1, and continue to stir to make the microcapsule latent curing agent selected from modified imidazole or modified amine uniformly dispersed in the system.

[0013] S3. Homogenization and preparation of functional additives: Add the remaining filler, leveling agent and brightening agent to the mixing system of step S2, and stir again until all components are fully mixed and homogeneous to obtain the finished product.

[0014] Preferably, the total mass of the epoxy reactive diluent and the filler is... The filler is added in batches, and with the shear force provided by mechanical stirring, a pre-dispersed slurry is preferentially constructed to prevent filler agglomeration and promote the initial adjustment of resin viscosity by the epoxy active diluent.

[0015] Preferably, in step S2, the stirring process requires shear heat control, ensuring that the temperature within the reaction system does not exceed the limit due to frictional heat generation. This ensures the latent stability of the adhesive during storage at room temperature.

[0016] Preferably, in step S3, after adding the leveling agent and the brightening agent, the interfacial tension is adjusted by continuous stirring to improve the fluidity of the system, and the final viscosity is finely adjusted by adding the remaining filler.

[0017] Preferably, the temperature parameters are strictly controlled throughout the entire preparation method:

[0018] The temperature of the reaction system in steps S1 to S3 is maintained at room temperature throughout. Between these elements, the chemical inertness of the epoxy resin system is maintained.

[0019] Preferably, the kinetic parameters in the preparation method are controlled as follows:

[0020] The stirring speed is adjusted between 200 rpm and 500 rpm according to the capacity of the reactor and the viscosity of the material to achieve laminar flow mixing;

[0021] The total stirring time is controlled between 30 and 60 minutes, and the system reaches a microscopic homogeneous state.

[0022] The application of a single-component flap wheel outer edge adhesive is characterized by:

[0023] The adhesive is applied directly to the outer edge of the flap wheel as a non-mixing, single-component material. The adhesive's natural penetration properties at controlled viscosity are used to fill the gaps in the flap wheel matrix. Subsequently... Under certain conditions, the epoxy resin is heated and cured for 3-4 hours. Heating causes the microcapsule latent curing agent, selected from modified imidazole or modified amine, to release its active components, thereby initiating a crosslinking reaction and achieving curing.

[0024] This invention provides a single-component adhesive for the outer edge of flap wheels, its preparation method, and its application. Compared with the prior art, it has the following improvements and advantages:

[0025] 1. This solution uses microcapsule latent curing agents selected from modified imidazole or modified amines, combined with a strict shear heat control process, which solves the pain points of traditional two-component adhesives that require on-demand mixing and have extremely short operating periods. Frictional heat is removed by cooling water, and the microcapsule latent curing agents selected from modified imidazole or modified amines are uniformly suspended in micron-sized particles without dissolving.

[0026] 2. This solution achieves deep wetting of the adhesive into the micro-gaps of the flap wheel substrate by synergistically adjusting the ratio of epoxy reactive diluent, leveling agent, and filler. The leveling agent molecules are oriented at the gas-liquid interface to reduce surface tension, giving the adhesive self-driven penetration ability in the gaps between the flaps. In the initial stage of heat curing, since the microcapsule latent curing agent selected from modified imidazole or modified amine has not yet been unsealed, the viscosity of the adhesive further decreases with increasing temperature, completing the secondary penetration into the micro-gaps, and then triggering explosive cross-linking to form a high-strength anchoring structure. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0028] Example 1:

[0029] This invention provides a single-component adhesive for the outer edge of flap wheels, comprising the following raw materials by mass percentage, wherein the content of each component meets the following ranges and the sum is 100%: 30% epoxy reactive diluent; 15% microencapsulated latent curing agent selected from modified imidazole or modified amine; and epoxy reactive diluent. ;filler The filler is one or more of quartz powder, talc powder, or aluminum hydroxide; when it is a mixture of multiple fillers, their total mass percentage is within the above range; leveling agent. The leveling agent is an organosilicon leveling agent; the gloss agent... The brightener is a high-molecular-weight polyester brightener;

[0030] In this formulation system, epoxy resin serves as the matrix resin to provide basic adhesive strength. Specifically, the epoxy resin is a bisphenol A type epoxy resin, such as epoxy resin with the brand name E-51, with an epoxy equivalent of approximately 184-194 g / eq. The epoxy reactive diluent is specifically butyl glycidyl ether or C12-14 glycidyl ether, selected at a 30% mass ratio to construct a low-viscosity system with a higher proportion of epoxy reactive diluent, thus meeting the deep penetration requirements of high-density flap wheels. Modified imidazoles or modified amines are also used. The microcapsule latent curing agent is selected at a mass ratio of 15%, specifically a modified imidazole microcapsule curing agent, such as 2-ethyl-4-methylimidazolium as the core material and polyurethane as the wall material, with an average particle size of 5-10 μm. It can provide sufficient crosslinking density during the curing stage to compensate for the strength loss that may be caused by low resin content. The addition of 30% epoxy reactive diluent significantly reduces the initial viscosity of the system, and improves the compatibility of leveling agent and brightener by utilizing the solvation effect, thus constructing a highly permeable liquid phase carrier.

[0031] The preparation method of this embodiment adopts a multi-stage dispersion process, including the following steps: S1, base material premixing and wetting: epoxy resin, epoxy reactive diluent and part of the filler are added to a reaction vessel and stirred at room temperature to allow the filler to complete the initial wetting and encapsulation in the resin system, forming a basic mixture; in step S1, part of the filler is added in batches, combined with the shear force provided by mechanical stirring, to preferentially build a pre-dispersed slurry, so as to prevent filler agglomeration and promote the initial adjustment of resin viscosity by epoxy reactive diluent; at the same time, the reaction system temperature in step S1 is always controlled at room temperature. The stirring speed is adjusted at 200 rpm according to the capacity of the reactor and the viscosity of the material to achieve laminar flow mixing, and the total stirring time is controlled at 30 minutes.

[0032] In step S1, the amount of filler added is 10%-80% of the total mass of filler in the final product. In this step, 10% of the total filler, i.e. 2% of the total formulation, is added first. The low viscosity environment under low solid content promotes the rapid penetration of epoxy reactive diluent molecules into the microporous structure of the filler particles to complete deep wetting. The low-speed laminar flow stirring strategy of 200 rpm effectively avoids air entrainment caused by turbulence and prevents local hot spots caused by high shear, creating a safe thermodynamic environment for the subsequent addition of heat-sensitive components.

[0033] The 200 rpm and 30 minutes selected here are the lower critical values ​​of the process window. Boundary verification tests show that if the stirring speed is lower than 180 rpm or the time is less than 25 minutes, the shear energy of the system is insufficient to overcome the van der Waals forces between the packing materials, resulting in micro-agglomerates larger than 50 μm in the finished product; while The temperature setting is to prevent the resin viscosity from being too high at lower temperatures, which would affect the wetting efficiency.

[0034] S2. Low-temperature blending of curing agent: Add a microencapsulated latent curing agent selected from modified imidazole or modified amine to the basic mixture obtained in step S1, and continue stirring to ensure that the microencapsulated latent curing agent selected from modified imidazole or modified amine is uniformly dispersed in the system; in step S2, shear heat control is required during the stirring process to prevent the temperature in the reaction system from exceeding the limit due to frictional heat generation. This ensures the latent stability of the adhesive during storage at room temperature;

[0035] During this period, air is introduced through the reactor jacket. The cooling water removes frictional heat, and the flow rate is adjusted in real time based on feedback from the in-vessel temperature sensor to ensure that the temperature difference between the system's center and the wall does not exceed a certain limit during large-capacity production. Maintaining the system temperature constant at The addition of microcapsule latent curing agents selected from modified imidazoles or modified amines allows them to be uniformly suspended in the resin matrix as micron-sized particles through gentle dispersion, rather than dissolved. This physical suspension state is the key mechanism for achieving long-term storage of single components.

[0036] S3. Homogenization and preparation of functional additives: Add the remaining filler, leveling agent and brightener to the mixing system of step S2, and stir again until all components are fully mixed and homogeneous to obtain the finished product; In step S3, after adding the leveling agent and brightener, the interfacial tension is adjusted by continuous stirring to improve the fluidity of the system, and the final viscosity is finely adjusted by adding the remaining filler.

[0037] The addition of the remaining 18% filler brings the system viscosity back to the working range, preventing the adhesive from becoming too thin and flowing; the leveling agent molecules are oriented at the gas-liquid interface, which significantly reduces the surface tension and gives the adhesive the ability to penetrate the gaps between the flap wheel blades, allowing the adhesive to reach deep into the matrix.

[0038] This embodiment also relates to the application of a one-component flap wheel outer edge adhesive. The adhesive is directly applied to the outer edge of the flap wheel as a non-mixing, one-component material. The adhesive's natural penetration properties at controlled viscosity fill the gaps in the flap wheel matrix. Subsequently... Under certain conditions, the epoxy resin is cured by heating for 3-4 hours. Heating causes the microcapsule latent curing agent, selected from modified imidazole or modified amine, to release its active components, thereby initiating a cross-linking reaction and achieving curing.

[0039] Specifically, the prepared adhesive is directly injected into the storage tank of the automatic glue applicator. Heating and curing for 3 hours; because the microcapsule latent curing agent selected from modified imidazole or modified amine in the system remains inert before reaching the unsealing temperature, the viscosity of the adhesive further decreases in the early stage of heating. Taking advantage of this physical window period, the secondary penetration of the micro gaps is completed. Subsequently, the curing agent unsealing triggers explosive cross-linking, forming a high-strength anchoring structure.

[0040] Example 2:

[0041] This embodiment provides a single-component louvered wheel outer edge adhesive, which is composed of the following raw materials by mass percentage, wherein the content of each component meets the following range and the sum is 100%: epoxy resin 48%; microencapsulated latent curing agent selected from modified imidazole or modified amine 10%; epoxy reactive diluent 22%; filler 15%; leveling agent 3%; gloss agent 2%.

[0042] The filler added in step S1 accounts for 10%-80% of the total mass of the filler;

[0043] In this embodiment, the ratio of 48% epoxy resin to 22% epoxy reactive diluent forms a medium viscosity system, designed to balance penetration rate and coating amount, suitable for medium-density flap wheel products; the 15% filler ratio serves as an intermediate gradient, reducing fluid yield stress compared to a high filler system, increasing wetting rate in complex blade structures, while retaining sufficient thixotropy to prevent sagging; the 10% use of a microcapsule latent curing agent selected from modified imidazole or modified amines, specifically using modified amine microcapsule curing agents, such as modified aliphatic amines as the core material and cross-linked polymethyl methacrylate as the wall material, provides standard curing kinetics, ensures curing speed, controls exothermic peak temperature, and prevents internal stress cracking caused by rapid polymerization;

[0044] The preparation method of this embodiment adopts a multi-stage dispersion process, including the following steps: S1, base material premixing and wetting: epoxy resin, epoxy reactive diluent and part of the filler are added to a reaction vessel and stirred at room temperature to allow the filler to complete the initial wetting and encapsulation in the resin system, forming a basic mixture; in step S1, part of the filler is added in batches, combined with the shear force provided by mechanical stirring, to preferentially build a pre-dispersed slurry, so as to prevent filler agglomeration and promote the initial adjustment of resin viscosity by epoxy reactive diluent; at the same time, the reaction system temperature in step S1 is always controlled at room temperature. The stirring speed is adjusted to 350 rpm according to the capacity of the reactor and the viscosity of the material to achieve laminar flow mixing; the total stirring time is controlled at 45 minutes.

[0045] In this step, 50% of the total filler volume, or 7.5% of the total formulation, is added, and the stirring speed is increased to 350 rpm. This is because as the resin content increases, the system's basic viscosity rises, requiring higher shear input power to break up filler agglomerates. The extended stirring time of 45 minutes ensures that the epoxy reactive diluent can still fully wet the filler surface through diffusion in a high-viscosity medium. The parameter selection of 350 rpm falls within the aforementioned range, with the geometric center of 200-500 rpm being the optimal laminar / turbulent transition point calculated based on the Reynolds number. This verifies the applicability of the intermediate value within the range, ensuring better dispersion efficiency than in the low-speed region while avoiding the risk of temperature rise in the high-speed region.

[0046] S2. Low-temperature blending of curing agent: Add a microcapsule latent curing agent selected from modified imidazole or modified amine to the basic mixture obtained in step S1, and continue stirring to ensure that the microcapsule latent curing agent selected from modified imidazole or modified amine is uniformly dispersed in the system. In step S2, shear heat control is required during the stirring process. Frictional heat is removed by a cooling medium to ensure that the temperature in the reaction system is always lower than the initial reaction temperature of the microcapsule latent curing agent, and the temperature of the reaction system is controlled not to exceed [a certain value]. This ensures the latent stability of the adhesive during storage at room temperature;

[0047] Given the increased stirring speed, this step requires strict monitoring of the vessel temperature; if the sensor reading exceeds [a certain value], [the temperature will be checked]. It immediately and automatically reduces the speed and increases the cooling water flow to prevent local overheating from causing premature desealing of the microcapsule latent curing agent selected from modified imidazole or modified amine.

[0048] S3. Homogenization and preparation of functional additives: Add the remaining filler, leveling agent and brightener to the mixing system of step S2, and stir again until all components are fully mixed and homogeneous to obtain the finished product; In step S3, after adding the leveling agent and brightener, the interfacial tension is adjusted by continuous stirring to improve the fluidity of the system, and the final viscosity is finely adjusted by adding the remaining filler.

[0049] After adding the remaining 7.5% filler, the system exhibits ideal thixotropic properties, meaning it has good fluidity under stirring and shearing, and its viscosity rapidly recovers when at rest. This characteristic effectively prevents sagging after coating.

[0050] Example 3:

[0051] This embodiment provides a single-component louvered wheel outer edge adhesive, which is composed of the following raw materials by mass percentage, wherein the content of each component meets the following range and the sum is 100%: epoxy resin 50%; microencapsulated latent curing agent selected from modified imidazole or modified amine 12%; epoxy reactive diluent 10%; filler 20%; leveling agent 5%; gloss agent 3%;

[0052] This embodiment aims to prepare a high-strength, highly thixotropic adhesive. The upper limit of 50% epoxy resin imparts extremely high mechanical strength and abrasion resistance to the cured product, making it suitable for heavy-duty sanding applications. The microencapsulated latent curing agent used is selected from modified imidazoles or modified amines, and is a microencapsulated modified imidazole, for example, using 1-cyanoethyl-2-ethyl-4-methylimidazolium as the core material. The lower limit of 10% epoxy reactive diluent results in a high initial viscosity of the system. A high addition of 5% leveling agent helps improve flowability and prevent sagging, and 3% gloss agent enhances the appearance and texture.

[0053] The preparation method of this embodiment adopts a multi-stage dispersion process, including the following steps: S1, base material premixing and wetting: epoxy resin, epoxy reactive diluent and part of the filler are added into the reaction vessel, and the temperature of the reaction system in step S1 is always controlled at room temperature. The stirring speed is adjusted to 500 rpm according to the capacity of the reactor and the viscosity of the material, and the total stirring time is controlled at 60 minutes.

[0054] For high-viscosity systems, step S1 involves adding 80% of the total filler, or 16% of the total formulation, and employs high-shear force dispersion at 500 rpm followed by 60 minutes of prolonged stirring. The upper limit of temperature control is achieved by using moderate heat to help reduce resin viscosity and promote filler dispersion, while the temperature does not reach the activation red line of the curing agent.

[0055] The settings here are 500 RPM and 60 minutes, and These are all upper critical values ​​of the process window; destructive testing has verified that when the stirring speed exceeds 550 rpm or the time exceeds 70 minutes, although the dispersion improves slightly, the system temperature will run out of control due to the accumulation of shear heat. This causes the capsule walls of microcapsule latent curing agents selected from modified imidazoles or modified amines to soften, shortening the shelf life to less than one month. Therefore, strictly limiting this upper limit is the key to balancing the need for high viscosity dispersion with thermal stability.

[0056] S2. Low-temperature blending of curing agent: Add microcapsule latent curing agent selected from modified imidazole or modified amine to the base mixture obtained in step S1. Shear heat control is required during the stirring process. Dispersing the curing agent in high-viscosity base material can easily generate local frictional heat. Therefore, this step adopts a pulse stirring strategy, stirring for 5 minutes and stopping for 1 minute to balance the heat of the system and maintain latent stability.

[0057] S3. Homogenization of functional additives: Add the remaining filler, leveling agent and brightener to the mixing system of step S2. Adjust the interfacial tension by continuous stirring. After adding the remaining 4% filler and high proportion of leveling agent, the leveling agent molecules quickly migrate to the surface, which significantly reduces the surface tension of the high viscosity system. This allows the adhesive to wet the substrate even though it is viscous, achieving a balance between high strength and workability.

[0058] Example 4:

[0059] This embodiment provides a single-component louver wheel outer edge adhesive, which is composed of the following raw materials by mass percentage, wherein the content of each component meets the following ranges and the sum is 100%: epoxy resin 50%; microencapsulated latent curing agent selected from modified imidazole or modified amine 8%; epoxy reactive diluent 30%; filler 5%; leveling agent 5%; gloss agent 2%;

[0060] This formulation focuses on rapid penetration and leveling performance, with the filler content set at the lower limit of 5% of the above range. The aim is to create a fluid system with extremely low solids content, minimizing the obstruction of flow by particles. Combined with 30% epoxy reactive diluent and 5% high leveling agent, a fluid system with extremely low surface tension is created, which can quickly fill the tiny gaps in the flap wheel matrix and is suitable for the manufacture of fine-grained, high-density precision flap wheels.

[0061] The preparation method in this embodiment employs a multi-stage dispersion process, including S1, premixing and wetting of the base material, with temperature controlled at... Mixing speed 300 rpm, mixing time 40 minutes;

[0062] In stage S1, 50% of the total filler is added, which is 2.5% of the total formulation. The appropriate stirring parameters are intended to maintain the laminar flow state of the system and prevent the introduction of air bubbles due to excessive shearing. This is especially important for low viscosity, high penetration formulations. After curing, the adhesive layer is free of pore defects.

[0063] S2. The curing agent is blended at low temperature. Under this low viscosity environment, the curing agent tends to settle more. Therefore, the stirring process must be continuous and accompanied by a bottom scraper to prevent the curing agent from settling in dead corners.

[0064] S3. After homogenizing and mixing the functional additives, add the remaining 2.5% filler. Through the synergistic effect of the leveling agent and the epoxy reactive diluent, this adhesive exhibits excellent natural penetration properties, achieving deep wetting without vacuum assistance.

[0065] Example 5:

[0066] This embodiment provides a single-component flap wheel outer edge adhesive, which is composed of the following raw materials by mass percentage, wherein the content of each component meets the following range and the sum is 100%: epoxy resin 48%; microencapsulated latent curing agent selected from modified imidazole or modified amine 12%; epoxy reactive diluent 15%; filler 18%; leveling agent 4%; gloss agent 3%;

[0067] This formula is designed for high solids and rapid curing. The 48% epoxy resin content provides excellent cohesion, while the 12% curing agent content combined with 3% gloss agent not only improves the appearance, but also works synergistically with the filler to enhance the surface hardness of the cured product, making the finished product both beautiful and durable.

[0068] The preparation method in this embodiment employs a multi-stage dispersion process, including S1, premixing and wetting of the base material, with temperature controlled at... Mixing speed 400 rpm, mixing time 50 minutes;

[0069] In stage S1, 60% of all fillers are added. The high stirring speed and time are to break up filler agglomerates in the high resin content system and build a uniform mechanical framework.

[0070] S2 and curing agent are blended at low temperature, with the temperature strictly controlled not exceeding [a certain value]. This allows for a sufficient latency period for the subsequent rapid curing reaction;

[0071] S3. After homogenizing and mixing the functional additives, add the remaining fillers and additives. The uniform dispersion of the brightener is completed in this step. The dense film layer formed on the microscopic surface effectively blocks oxygen from interfering with the curing reaction and improves the surface drying speed.

[0072] Comparative Example 1:

[0073] This comparative example uses a traditional two-component epoxy resin adhesive; component A is bisphenol A type epoxy resin, and component B is a modified amine curing agent, mixed at a mass ratio of 2:1 before use; it does not contain microencapsulated latent curing agents selected from modified imidazole or modified amines, nor does it contain finely formulated leveling agents and gloss agents. This comparative example aims to verify the fundamental differences between the one-component system and the traditional two-component system in terms of ease of handling and storage stability.

[0074] Comparative Example 2:

[0075] This comparative example uses the same raw material ratio as Example 2, but does not employ a multi-stage dispersion process. Epoxy resin, a microencapsulated latent curing agent selected from modified imidazole or modified amines, epoxy reactive diluent, and filler are added to the reactor all at once and mixed for 60 minutes under high-speed stirring at 500 rpm. Strict shear heat control is not performed, and the reaction temperature rises to [temperature missing]. The core temperature of the material was monitored in real time by thermocouples inserted into the lining of the reactor, and the temperature rise process was observed. This comparative example was used to verify the necessity of multi-stage dispersion process and shear heat control for maintaining the stability of microcapsule latent curing agents selected from modified imidazole or modified amine.

[0076] Comparative Example 3:

[0077] This comparative example uses a single-component system, but without the addition of leveling agents and gloss agents; the formulation is: 50% epoxy resin, 15% microencapsulated latent curing agent selected from modified imidazole or modified amine, 15% epoxy reactive diluent, and 20% filler; this comparative example is used to verify the key roles of functional additives, leveling agents, and gloss agents in the system's penetration ability and appearance quality.

[0078] Comparative Example 4:

[0079] This comparative example uses a single-component system, but the content of epoxy reactive diluent is lower than the above range, only 5%; the formulation is: 60% epoxy resin, 15% microencapsulated latent curing agent selected from modified imidazole or modified amine, 5% epoxy reactive diluent, 15% filler, 3% leveling agent, and 2% gloss agent. This comparative example is used to verify the critical effect of the epoxy reactive diluent ratio on the system viscosity and penetration depth.

[0080] Verification experiment:

[0081] The performance of the single-component flap wheel adhesives prepared in Examples 1-5 and Comparative Examples 1-4 was tested, and the test results are shown below:

[0082] Storage period, Seal an appropriate amount of adhesive in the designated container and place it in... In a constant temperature chamber; periodically remove and use a rotational viscometer to measure the viscosity. Measure the viscosity at the selected rotor and speed; current viscosity value. Reaching initial viscosity of When this happens, it is deemed invalid;

[0083] Penetration depth: Apply the adhesive to the outer edge of a standard 100-type flap wheel, allow it to penetrate naturally for 5 minutes and then cure. Cut the wheel open and measure the average depth of the adhesive penetration into the substrate.

[0084] Shear strength: According to GB / T7124 standard, the lap shear strength after curing was tested using a universal testing machine at a tensile speed of 2 mm / min.

[0085] Appearance gloss: Visually inspect the smoothness and gloss of the cured adhesive layer surface, and classify it into three levels: excellent, average, and poor.

[0086] The cured adhesive layer in each embodiment is dense, without visible air bubbles, and the cross-section shows a uniform particle distribution.

[0087] Table 1 Performance test data of Examples 1-5 and Comparative Examples 1-4

[0088]

[0089] As can be seen from the data analysis in Table 1, the single-component flap wheel outer edge adhesives of Examples 1-5 have a significant advantage in terms of storage period, all reaching more than 6 months, which solves the defect of the short working period of the two-component adhesive in Comparative Example 1, which is only 2 hours, and realizes the possibility of automated production without mixing; this is attributed to the chemical inertness of the microcapsule latent curing agent selected from modified imidazole or modified amine at room temperature, as well as the strict temperature control during the preparation process;

[0090] Regarding permeability, Example 4 achieved a maximum permeation depth of 9.4 mm by reducing the filler content to 5% and combining it with 30% epoxy reactive diluent, verifying the necessity of low filler content for precision permeation scenarios. In contrast, Example 3, using 20% ​​filler and 10% epoxy reactive diluent, achieved a permeation depth of only 4.1 mm but a shear strength as high as 26.8 MPa, demonstrating the strength advantage of high-filler systems; Example 2, with 15% filler, achieved a balance between a permeation depth of 7.2 mm and a strength of 24.2 MPa. This indicates that within the aforementioned defined filler range of 5%-20%, the rheological properties of the adhesive can be precisely controlled by adjusting the proportion to meet the needs of flap wheels with different densities.

[0091] Example 1, due to the use of a low viscosity ratio of 30% epoxy resin and 30% epoxy reactive diluent, combined with the effect of leveling agent, achieved a penetration depth of 8.5 mm, which is significantly better than Comparative Example 3 (2.1 mm without leveling agent) and Comparative Example 4 (1.2 mm with insufficient epoxy reactive diluent). This indicates that the synergistic effect of the low viscosity carrier provided by epoxy reactive diluent and the reduction of surface tension by leveling agent is crucial for overcoming the capillary resistance between flaps and achieving the aforementioned natural penetration characteristics.

[0092] Comparing Example 2 and Comparative Example 2, it can be seen that although the formulations are completely identical, Comparative Example 2 did not employ the multi-stage dispersion process of the present invention and did not control the shear heat, resulting in the temperature rising to [missing information]. This results in some of the microcapsule latent curing agents selected from modified imidazoles or modified amines being prematurely activated during the preparation process due to frictional heat, leading to a significant reduction in the storage period to 2.5 months. This result strongly demonstrates the necessity of shear heat control in step S2 for maintaining the chemical inertness of the system.

[0093] In summary, this invention achieves an excellent combination of long storage period, controllable permeation, and high strength through precise component compatibility, especially the gradient design of fillers in the 5%-20% range and the preparation process controlled by kinetic parameters.

[0094] 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.

Claims

1. A single-component adhesive for the outer edge of a flap wheel, characterized in that, This adhesive is composed of the following raw materials by weight percentage, with the content of each component meeting the following ranges and the sum being 100%: Epoxy resin 30%-50%; A microcapsule latent curing agent, selected from modified imidazole or modified amine compounds, used in an amount of 5%-15%; Epoxy reactive diluent 10%-30%; The filler is 5%-20%, and the filler is one or more of quartz powder, talc powder or aluminum hydroxide; when it is a mixture of multiple fillers, the total mass percentage is within the above range; the leveling agent is 1%-5%, and the leveling agent is an organosilicon leveling agent; the brightener is 1%-3%, and the brightener is a high molecular weight polyester brightener.

2. A method for preparing a single-component flap wheel outer edge adhesive as described in claim 1, characterized in that, The multi-stage dispersion process includes the following steps: S1. Base material premixing and wetting: The epoxy resin, the epoxy active diluent, and fillers accounting for 10%-80% of the total mass of the fillers are put into the reactor and stirred at room temperature to allow the fillers to complete the initial wetting and encapsulation in the resin system, forming a basic mixture. S2. Low-temperature blending of curing agent: Add the microcapsule latent curing agent selected from modified imidazole or modified amine to the basic mixture obtained in step S1, and continue to stir to make the microcapsule latent curing agent selected from modified imidazole or modified amine uniformly dispersed in the system. S3. Homogenization and preparation of functional additives: Add the remaining filler, leveling agent and brightening agent to the mixing system of step S2, and stir again until all components are fully mixed and homogeneous to obtain the finished product.

3. The method for preparing a single-component flap wheel outer edge adhesive according to claim 2, characterized in that, The total mass of the epoxy reactive diluent and the filler The filler is added in batches, and with the shear force provided by mechanical stirring, a pre-dispersed slurry is preferentially constructed to prevent filler agglomeration and promote the initial adjustment of resin viscosity by the epoxy active diluent.

4. The method for preparing a single-component flap wheel outer edge adhesive according to claim 2, characterized in that, In step S2, the stirring process requires shear heat control to ensure that the temperature within the reaction system does not exceed the limit due to frictional heat generation. This ensures the latent stability of the adhesive during storage at room temperature.

5. The method for preparing a single-component flap wheel outer edge adhesive according to claim 2, characterized in that, In step S3, after adding the leveling agent and the brightening agent, the interfacial tension is adjusted by continuous stirring to improve the fluidity of the system, and the final viscosity is fine-tuned by adding the remaining filler.

6. The method for preparing a single-component flap wheel outer edge adhesive according to claim 2, characterized in that, The preparation method strictly controls temperature parameters throughout the entire process. The temperature of the reaction system in steps S1 to S3 is maintained at room temperature throughout. Between C, to maintain the chemical inertness of the epoxy resin system.

7. The method for preparing a single-component flap wheel outer edge adhesive according to claim 2, characterized in that, The kinetic parameters in the preparation method are controlled as follows: The stirring speed is adjusted between 200 rpm and 500 rpm according to the capacity of the reactor and the viscosity of the material to achieve laminar flow mixing; The total stirring time is controlled between 30 and 60 minutes, and the system reaches a microscopic homogeneous state.

8. The application of a single-component flap wheel outer edge adhesive as described in claim 1, characterized in that: The adhesive is applied directly to the outer edge of the flap wheel as a non-mixing, single-component material. The adhesive's natural penetration properties at controlled viscosity are used to fill the gaps in the flap wheel matrix. Subsequently... Under certain conditions, the epoxy resin is heated and cured for 3-4 hours. Heating causes the microcapsule latent curing agent, selected from modified imidazole or modified amine, to release its active components, thereby initiating a crosslinking reaction and achieving curing.

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