High-viscosity stain-resistant acrylate adhesive and preparation method thereof

Abstract

The invention discloses a high-viscosity stain-resistant acrylate adhesive and a preparation method thereof, and relates to the technical field of adhesives. The high-viscosity stain-resistant acrylate adhesive is prepared from the following raw materials in parts by weight: 50 to 70 parts of modified acrylate, 5 to 10 parts of modified filler, 20 to 30 parts of elastomer, 1 to 3 parts of initiator, 1 to 5 parts of cross-linking agent, 1 to 3 parts of plasticizer and 40 to 70 parts of methylbenzene. The acrylate adhesive has high viscosity, and can meet the high bonding strength scene; the paint has good stain resistance and can be kept clean for a long time; high and low temperature resistance and extreme environment adaptation are realized; the flame retardance is realized, and the safety is high; in addition, a three-dimensional cross-linked network constructed by the initiator and the cross-linking agent enhances cohesion and mechanical strength, improves comprehensive properties such as chemical resistance and the like, and has wide application prospects in multiple fields.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly to a high-viscosity and stain-resistant acrylate adhesive and a preparation method thereof. Background Art

[0002] Due to its excellent bonding performance, acrylate adhesives can form a firm connection between various materials. At the same time, their good chemical resistance enables them to maintain a stable bonding effect when facing the erosion of various chemical substances. Based on these advantages, they have been widely used in many fields such as construction, automotive manufacturing, and electronic device production. However, with the rapid development of industry and the increasing complexity of application scenarios, the existing acrylate adhesives have exposed many deficiencies in performance.

[0003] In terms of high viscosity, in some application scenarios with extremely high requirements for bonding strength, such as the bonding of aircraft components in the aerospace field, the viscosity of ordinary acrylate adhesives is difficult to meet the long-term and high-strength stress requirements, and debonding is likely to occur. In terms of stain resistance, when used for the bonding of outdoor building decoration or automotive exterior components, the surface of the adhesive is extremely prone to adsorbing pollutants such as dust and oil stains, which not only affects the appearance but may also reduce the bonding performance due to the erosion of dirt.

[0004] In terms of high and low temperature resistance, in extremely cold or hot environments, such as polar scientific research equipment or industrial facilities in desert areas, ordinary acrylate adhesives will have problems such as embrittlement and softening, resulting in bonding failure. In terms of flame retardancy, when applied inside electronic devices or in building fire prevention areas, traditional adhesives are difficult to meet strict flame retardancy standards and pose a great potential safety hazard. In addition, in terms of reusability, most of the current acrylate adhesives are difficult to disassemble after curing and cannot meet the product requirements of some products that require flexible assembly and disassembly, which not only causes waste of resources but also is not conducive to the maintenance and upgrading of products. Therefore, it is urgent to develop an acrylate adhesive with a variety of excellent properties, which has important practical significance for promoting the development of related industries. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a high-viscosity and stain-resistant acrylate adhesive and a preparation method thereof, which solve the problems of insufficient viscosity and poor stain resistance.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A high-viscosity and stain-resistant acrylate adhesive, comprising the following raw materials in parts by weight: 50 - 70 parts of modified acrylate, 5 - 10 parts of modified filler, 20 - 30 parts of elastomer, 1 - 3 parts of initiator, 1 - 5 parts of crosslinking agent, 1 - 3 parts of plasticizer, and 40 - 70 parts of toluene.

[0007] Further, the modified acrylate comprises the following raw materials in parts by weight: 30-50 parts of ethyl acrylate monomer, 10-20 parts of 2-hydroxyethyl acrylate, 3-5 parts of p-toluenesulfonic acid, 50-70 parts of toluene, 3-8 parts of perfluorooctylethyl acrylate fluorine-containing compound, 10-20 parts of 2,2'-dithiobisethanol, and 2-4 parts of dibutyltin dilaurate; The specific preparation steps of the modified acrylate are as follows: A1. Place a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser in an oil bath, turn on the stirrer, stir at a speed of 200-300 r / min, and sequentially and slowly add ethyl acrylate monomer and 2-hydroxyethyl acrylate into the three-necked flask under stirring conditions. Slowly raise the temperature of the oil bath to 80-100 °C, stir for 20-40 minutes, then add p-toluenesulfonic acid, and continue the reaction for 1-2 hours while continuously stirring. After the reaction is completed, naturally cool to room temperature to obtain a preliminary modified product; A2. Transfer the preliminary modified product to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. Add toluene solvent to the reaction kettle, turn on the stirrer, stir at a speed of 300-400 r / min, then add perfluorooctylethyl acrylate, raise the temperature of the reaction kettle to 60-80 °C, keep stirring, and react for 1-2 hours. After the reaction is completed, remove toluene by vacuum distillation at 1-10 kPa to obtain a secondary modified product; A3. Transfer the secondary modified product to a reaction vessel equipped with a stirrer and a thermometer, turn on the stirrer, stir at a speed of 200-300 r / min, control the temperature of the reaction vessel at 50-70 °C, and add 2,2'-dithiobisethanol to the reaction vessel at a dropping rate of 1-3 mL per minute using a constant pressure dropping funnel. After the dropping is completed, slowly and evenly add dibutyltin dilaurate, stir and react for 1-2 hours. After the reaction is completed, cool the reaction product to room temperature, filter it with a Buchner funnel and wash it with anhydrous ethanol. Transfer the product to a separatory funnel, add anhydrous ethanol, shake it well and mix, then let it stand for stratification, separate the lower organic phase, repeat the washing operation 2-4 times, and dry it in a drying oven at 80-90 °C for 1-2 hours to obtain the modified acrylate.

[0008] Further, the modified filler comprises the following raw materials in parts by weight: 60-80 parts of ethanol, 15-30 parts of nano-montmorillonite, 8-15 parts of silane coupling agent KH-570, 2-5 parts of ammonium polyphosphate, 20-40 parts of toluene, 8-15 parts of polydimethylsiloxane, 1-5 parts of stannous octoate, 20-40 parts of petroleum ether, 2-6 parts of hindered amine light stabilizer GW-540, and 2-6 parts of antioxidant 168; The specific preparation steps of the modified filler are as follows: B1. Pour half of the ethanol solution into a three-necked flask. Slowly add the nanometer montmorillonite into the ethanol solution. Set the stirring speed to 300 - 400 r / min and stir for 20 - 40 minutes. Slowly drip the silane coupling agent KH-570 into the three-necked flask. After the dripping is completed, raise the temperature of the reaction system to 80 - 100 °C and keep the reaction for 1 - 2 hours. After the reaction is completed, centrifuge the product to separate, remove the supernatant, and wash the precipitate with anhydrous ethanol 3 - 5 times. Finally, place the washed product in a vacuum drying oven and dry it at 60 - 80 °C until constant weight. B2. Transfer the surface-treated nanoparticles to a high-speed stirrer, add ammonium polyphosphate, set the stirring speed to 800 - 1000 r / min, raise the temperature to 60 - 80 °C, and continuously stir and mix for 1 - 2 hours. B3. Add toluene to the reaction kettle. Add the above product and polydimethylsiloxane to the reaction kettle, turn on the stirrer, set the stirring speed to 200 - 300 r / min, and add stannous octoate as a catalyst. Raise the temperature of the reaction kettle to 50 - 70 °C and the reaction time is 1 - 2 hours. After the reaction is completed, remove the toluene solvent from the product by vacuum distillation at 10 - 20 kPa, then wash the product with petroleum ether 3 - 5 times, and dry the washed product in a vacuum drying oven at 60 - 80 °C for 2 - 3 hours. B4. Under normal temperature environment, transfer the obtained product to a container with a stirrer. Under the state of stirring speed of 100 - 200 r / min, sequentially add the hindered amine light stabilizer GW-540 and antioxidant 168 into the container and continuously stir for 30 - 60 minutes. After the stirring is completed, add anhydrous ethanol to the reaction container and continue to stir for 15 - 20 minutes. Then transfer the mixed solution to a centrifuge tube, put it into a centrifuge, centrifuge at a speed of 3000 - 5000 r / min for 5 - 10 minutes, pour out the supernatant, repeat the above washing and centrifugation operations 2 - 4 times, and transfer the washed modified filler to a vacuum drying oven and dry it at 40 - 60 °C for 2 - 3 hours to obtain the modified filler.

[0009] Further, the elastomer is one of nitrile rubber and polyurethane elastomer.

[0010] Further, the initiator is one of benzoyl peroxide, azobisisobutyronitrile, and dicumyl peroxide.

[0011] Further, the crosslinking agent is one of trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, and N,N'-methylenebisacrylamide.

[0012] Further, the plasticizer is one of dioctyl phthalate, dioctyl sebacate, and epoxidized soybean oil.

[0013] A preparation method of a highly viscous and stain-resistant acrylate adhesive, specifically comprising the following steps: S1. In a three-necked flask equipped with a stirring device, a thermometer, and a condenser, add toluene solvent and modified acrylate. Start the stirring device, control the stirring speed at 200 - 300 r / min, slowly add the elastomer, and slowly heat up to 50 - 80 °C at a rate of 1 - 2 °C / min. Stir until the elastomer is completely dissolved, stop heating and let the solution cool naturally. During the cooling process, keep the stirring speed at 100 - 200 r / min until the solution temperature drops to room temperature. Slowly add the plasticizer and continue to stir at a speed of 200 - 300 r / min for 30 - 40 minutes; S2. Divide the dried modified filler into several small portions and add one portion to the reaction kettle every 2 - 4 minutes. During the addition of the filler, increase the stirring speed to 300 - 400 r / min. After adding each portion of the filler, stir for 15 - 20 minutes and then add the next portion; after all the filler is added, increase the stirring speed to 500 - 600 r / min and continue to stir for 1 - 2 hours; S3. Adjust the stirring speed to 200 - 300 r / min, and slowly add the initiator and cross-linking agent in sequence. After adding each additive, stir for 5 - 10 minutes before adding the next additive; put the stirred adhesive solution into a vacuum drying oven and perform vacuum degassing at -0.08 - -0.1 MPa and 40 - 50 °C for 30 - 60 minutes. During this process, ultrasonically treat the solution for 5 - 10 minutes every 10 - 15 minutes. After degassing, a highly viscous and stain-resistant acrylate adhesive is obtained.

[0014] The present invention provides a highly viscous and stain-resistant acrylate adhesive and its preparation method, having the following beneficial effects: 1. In the modified acrylate, ethyl acrylate monomer and 2-hydroxyethyl acrylate undergo an esterification reaction under the catalysis of p-toluenesulfonic acid to form a polymer chain with multiple active groups. These active groups can form chemical bonds or physical adsorption with the surface of the adherend material, greatly enhancing the adhesion between the adhesive and the material. At the same time, the addition of the elastomer, whose long-chain structure interpenetrates the acrylate polymer network, forms an interpenetrating network structure. This structure effectively increases the flexibility and cohesion of the adhesive, enabling it to better disperse stress when subjected to external forces, avoiding debonding caused by local stress concentration, and thus significantly improving the viscosity of the adhesive to meet the requirements of high bonding strength scenarios.

[0015] 2. The perfluorooctylethyl acrylate fluorine-containing compound added in the preparation process of modified acrylate has extremely low surface energy in the fluorine atom in its molecule. After the adhesive is cured, the fluorine-containing compound will migrate to the surface of the adhesive, reducing the surface energy. When pollutants such as dust and oil contact the surface of the adhesive, due to the difference in surface energy, the pollutants are difficult to adhere to and spread on the surface, thus showing good stain resistance. When used for outdoor architectural decoration or automotive exterior parts bonding, it can remain clean for a long time, reducing the impact of dirt on the bonding performance.

[0016] 3. After the nano-montmorillonite in the modified filler is treated with a silane coupling agent, its lamellar structure is intercalated with the acrylic polymer. This composite structure can limit the movement of the polymer chain at high temperatures, enhance the thermal stability of the adhesive, and prevent softening; at low temperatures, the nano-montmorillonite lamellar layer acts as a physical barrier, inhibits the crystallization and embrittlement of the polymer chain, and maintains the flexibility and bonding performance of the adhesive. At the same time, the presence of the elastomer further improves the adaptability of the adhesive at different temperatures, broadens its operating temperature range, and enables it to maintain good bonding effects in extreme environments such as polar scientific research equipment and industrial facilities in desert areas.

[0017] 4. Ammonium polyphosphate added during the preparation of modified fillers will decompose at high temperatures to produce phosphoric acid, metaphosphoric acid and other substances, which will form a dense carbonized layer on the surface of the adhesive. The carbonized layer can isolate oxygen and heat, prevent the spread of flames, and play a flame retardant role. In addition, the non-combustible gases such as ammonia produced by the decomposition of ammonium polyphosphate can also dilute the concentration of combustible gases, further improving the flame retardant properties of the adhesive, making it safer in scenarios with strict flame retardant requirements such as inside electronic equipment and fire protection areas of buildings.

[0018] 5. The synergistic effect of initiators and crosslinkers enables the adhesive to form a three-dimensional crosslinked network structure. The initiator decomposes to produce free radicals, which trigger polymerization reactions of acrylate monomers and elastomers, while the crosslinker forms chemical bonds between polymer chains to connect the polymer chains together. This crosslinked network structure not only enhances the cohesive force and mechanical strength of the adhesive, but also improves its comprehensive properties such as chemical resistance and water resistance, prolongs the service life of the adhesive, and ensures its stable performance during long-term use. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1: A highly viscous stain-resistant acrylate adhesive, comprising the following raw materials in parts by weight: 50 parts of modified acrylate, 5 parts of modified filler, 20 parts of elastomer, 1 part of initiator, 1 part of crosslinking agent, 1 part of plasticizer, and 40 parts of toluene.

[0021] A preparation method of a highly viscous stain-resistant acrylate adhesive, specifically comprising the following steps: S1. In a three-necked flask equipped with a stirring device, a thermometer, and a condenser, add toluene solvent and modified acrylate. Start the stirring device, control the stirring speed at 200 r / min, slowly add nitrile rubber, and slowly heat up to 50 °C at a rate of 1 °C / min. Stir until the elastomer is completely dissolved, stop heating, and let the solution cool naturally. During the cooling process, keep the stirring speed at 100 r / min until the solution temperature drops to room temperature. Slowly add dioctyl phthalate and continue to stir at a speed of 200 r / min for 30 minutes; S2. Divide the dried modified filler into several small portions and add one portion to the reaction kettle every 2 minutes. During the addition of the filler, increase the stirring speed to 300 r / min. After adding each portion of the filler, stir for 15 minutes and then add the next portion; after all the fillers are added, increase the stirring speed to 500 r / min and continue to stir for 1 hour; S3. Adjust the stirring speed to 200 r / min, and slowly add benzoyl peroxide and trimethylolpropane trimethacrylate in sequence. After adding each additive, stir for 5 minutes before adding the next additive; put the stirred adhesive solution into a vacuum drying oven and perform vacuum degassing at -0.08 MPa and 40 °C for 30 minutes. During this process, ultrasonically treat the solution for 5 minutes every 10 minutes. After the degassing is completed, a highly viscous stain-resistant acrylate adhesive is obtained.

[0022] The modified acrylate comprises the following raw materials in parts by weight: 30 parts of ethyl acrylate monomer, 10 parts of 2-hydroxyethyl acrylate, 3 parts of p-toluenesulfonic acid, 50 parts of toluene, 3 parts of perfluorooctylethyl acrylate fluorine-containing compound, 10 parts of 2,2'-dithiobisethanol, and 2 parts of dibutyltin dilaurate; The specific preparation steps of the modified acrylate are as follows: A1. Place a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser in an oil bath. Start the stirrer and stir at a speed of 200 r / min. Under stirring conditions, slowly add ethyl acrylate monomer and 2-hydroxyethyl acrylate to the three-necked flask in sequence. Slowly raise the temperature of the oil bath to 80 °C, stir for 20 minutes, then add p-toluenesulfonic acid, and continue the reaction for 1 hour while continuously stirring. After the reaction is completed, naturally cool to room temperature to obtain a preliminary modified product; A2. Transfer the initially modified product to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. Add toluene solvent to the reaction kettle, turn on the stirrer, stir at a speed of 300 r / min, then add perfluorooctylethyl acrylate. Raise the temperature of the reaction kettle to 60 °C, keep stirring, and react for 1 hour. After the reaction is completed, remove toluene by vacuum distillation at 1 kPa to obtain the secondarily modified product; A3. Transfer the secondarily modified product to a reaction vessel equipped with a stirrer and a thermometer. Turn on the stirrer and stir at a speed of 200 r / min. Control the temperature of the reaction vessel at 50 °C. Use a constant-pressure dropping funnel to add 2,2'-dithiobisethanol to the reaction vessel at a dropping rate of 1 mL per minute. After the dropping is completed, slowly and evenly add dibutyltin dilaurate, and stir and react for 1 hour. After the reaction is completed, cool the reaction product to room temperature, filter it with a Buchner funnel and wash it with absolute ethanol. Transfer the product to a separating funnel, add absolute ethanol, shake it well and mix, then let it stand for stratification, separate the lower organic phase, repeat the washing operation 2 times, and dry it in a drying oven at 80 °C for 1 hour to obtain the modified acrylate.

[0023] The modified filler comprises the following raw materials in parts by weight: 60 parts of ethanol, 15 parts of nano-montmorillonite, 8 parts of silane coupling agent KH-570, 2 parts of ammonium polyphosphate, 20 parts of toluene, 8 parts of polydimethylsiloxane, 1 part of stannous octoate, 20 parts of petroleum ether, 2 parts of hindered amine light stabilizer GW-540, and 2 parts of antioxidant 168; The specific preparation steps of the modified filler are as follows: B1. Pour half of the ethanol solution into a three-necked flask, slowly add nano-montmorillonite to the ethanol solution, set the stirring speed to 300 r / min, and stir for 20 minutes; slowly drop silane coupling agent KH-570 into the three-necked flask. After the dropping is completed, raise the temperature of the reaction system to 80 °C and keep the reaction for 1 hour; after the reaction is completed, centrifuge the product to remove the supernatant, wash the precipitate with absolute ethanol 3 times, and finally place the washed product in a vacuum drying oven and dry it to constant weight at 60 °C; B2. Transfer the surface-treated nano-particles to a high-speed stirrer, add ammonium polyphosphate, set the stirring speed to 800 r / min, raise the temperature to 60 °C, and keep stirring and mixing for 1 hour; B3. Add toluene to the reaction kettle, add the above product and polydimethylsiloxane to the reaction kettle, turn on the stirrer, set the stirring speed to 200 r / min, and add stannous octoate as a catalyst. Raise the temperature of the reaction kettle to 50 °C and keep the reaction for 1 hour. After the reaction is completed, remove the toluene solvent from the product by vacuum distillation at 10 kPa, then wash the product with petroleum ether 3 times, and dry the washed product in a vacuum drying oven at 60 °C for 2 hours; B4. At room temperature, transfer the obtained product to a container equipped with a stirrer. With the stirring speed at 100 r / min, add hindered amine light stabilizer GW-540 and antioxidant 168 to the container in sequence, and continuously stir for 30 minutes. After the stirring is completed, add anhydrous ethanol to the reaction container, continue stirring for 15 minutes, then transfer the mixed solution to a centrifuge tube, place it in a centrifuge, centrifuge at a speed of 3000 r / min for 5 minutes, pour out the supernatant, repeat the above washing and centrifugation operations twice, and transfer the washed modified filler to a vacuum drying oven to dry at 40 °C for 2 hours to obtain the modified filler.

[0024] Example 2: A highly viscous and stain-resistant acrylate adhesive, comprising the following raw materials in parts by weight: 70 parts of modified acrylate, 10 parts of modified filler, 30 parts of elastomer, 3 parts of initiator, 5 parts of cross-linking agent, 3 parts of plasticizer, and 70 parts of toluene.

[0025] A preparation method of a highly viscous and stain-resistant acrylate adhesive specifically comprises the following steps: S1. In a three-necked flask equipped with a stirring device, a thermometer, and a condenser, add toluene solvent and modified acrylate, turn on the stirring device, control the stirring speed at 300 r / min, slowly add polyurethane elastomer, and slowly heat up to 80 °C at a rate of 2 °C / min. Stir until the elastomer is completely dissolved, stop heating, and let the solution cool naturally. During the cooling process, keep the stirring speed at 200 r / min until the solution temperature drops to room temperature. Slowly add dioctyl sebacate and continue stirring at a speed of 300 r / min for 40 minutes. S2. Divide the dried modified filler into several small portions and add one portion to the reaction kettle every 4 minutes. During the addition of the filler, increase the stirring speed to 400 r / min. After adding each portion of the filler, stir for 20 minutes and then add the next portion. After all the fillers are added, increase the stirring speed to 600 r / min and continue stirring for 2 hours. S3. Adjust the stirring speed to 300 r / min, and slowly add azobisisobutyronitrile and ethylene glycol dimethacrylate in sequence. Stir for 10 minutes after adding each auxiliary agent before adding the next one. Put the stirred adhesive solution into a vacuum drying oven and perform vacuum defoaming at -0.1 MPa and 50 °C for 60 minutes. During this process, perform ultrasonic treatment on the solution for 10 minutes every 15 minutes. After the defoaming is completed, a highly viscous and stain-resistant acrylate adhesive is obtained.

[0026] The modified acrylate comprises the following raw materials in parts by weight: 50 parts of ethyl acrylate monomer, 20 parts of 2-hydroxyethyl acrylate, 5 parts of p-toluenesulfonic acid, 70 parts of toluene, 8 parts of perfluorooctylethyl acrylate fluorine-containing compound, 20 parts of 2,2'-dithiobisethanol, and 4 parts of dibutyltin dilaurate. The modified acrylate is prepared through the following specific steps: A1. Place a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser in an oil bath. Start the stirrer and stir at a speed of 300 r / min. Under stirring conditions, slowly add ethyl acrylate monomer and 2-hydroxyethyl acrylate into the three-necked flask in sequence. Slowly raise the temperature of the oil bath to 100 °C. After stirring for 40 minutes, add p-toluenesulfonic acid, and continue the reaction for 2 hours while continuously stirring. After the reaction is completed, naturally cool to room temperature to obtain a preliminary modified product; A2. Transfer the preliminary modified product to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. Add toluene solvent to the reaction kettle. Start the stirrer and stir at a speed of 400 r / min. Then add perfluorooctylethyl acrylate. Raise the temperature of the reaction kettle to 80 °C and keep stirring. React for 2 hours. After the reaction is completed, remove toluene by vacuum distillation at 10 kPa to obtain a secondary modified product; A3. Transfer the secondary modified product to a reaction vessel equipped with a stirrer and a thermometer. Start the stirrer and stir at a speed of 300 r / min. Control the temperature of the reaction vessel at 70 °C. Use a constant pressure dropping funnel to add 2,2'-dithiobisethanol to the reaction vessel at a dropping rate of 3 mL per minute. After the dropping is completed, slowly and evenly add dibutyltin dilaurate, and stir and react for 2 hours. After the reaction is completed, cool the reaction product to room temperature, filter it with a Buchner funnel and wash it with absolute ethanol. Transfer the product to a separatory funnel, add absolute ethanol, shake well and mix, then let it stand for layering, separate the lower organic phase, repeat the washing operation 4 times, and dry it in a drying oven at 90 °C for 2 hours to obtain the modified acrylate.

[0027] The modified filler comprises the following raw materials in parts by weight: 80 parts of ethanol, 30 parts of nano-montmorillonite, 15 parts of silane coupling agent KH-570, 5 parts of ammonium polyphosphate, 40 parts of toluene, 15 parts of polydimethylsiloxane, 5 parts of stannous octoate, 40 parts of petroleum ether, 6 parts of hindered amine light stabilizer GW-540, and 6 parts of antioxidant 168; The modified filler is prepared through the following specific steps: B1. Pour half of the ethanol solution into a three-necked flask, slowly add nano-montmorillonite to the ethanol solution, set the stirring speed to 400 r / min, and stir for 40 minutes. Slowly drip silane coupling agent KH-570 into the three-necked flask. After the dripping is completed, raise the temperature of the reaction system to 100 °C and keep the reaction for 2 hours. After the reaction is completed, centrifuge the product to remove the supernatant, wash the precipitate with absolute ethanol 5 times, and finally place the washed product in a vacuum drying oven and dry it to constant weight at 80 °C; B2. Transfer the surface-treated nanoparticles to a high-speed blender, add ammonium polyphosphate, set the stirring speed at 1000 r / min, raise the temperature to 80 °C, and continuously stir and mix for 2 hours; B3. Add toluene to the reaction kettle, add the above product and polydimethylsiloxane to the reaction kettle, turn on the stirrer, set the stirring speed at 300 r / min, and add stannous octoate as a catalyst. Raise the temperature of the reaction kettle to 70 °C and the reaction time is 2 hours. After the reaction is completed, remove the toluene solvent from the product by vacuum distillation at 20 kPa, then wash the product 5 times with petroleum ether, and dry the washed product in a vacuum drying oven at 80 °C for 3 hours; B4. Under normal temperature environment, transfer the obtained product to a container with a stirrer. Under the condition of a stirring speed of 200 r / min, add the hindered amine light stabilizer GW-540 and antioxidant 168 to the container in sequence, and continuously stir for 60 minutes; after the stirring is completed, add anhydrous ethanol to the reaction container, continue to stir for 20 minutes, then transfer the mixed solution to a centrifuge tube, put it into a centrifuge, centrifuge at a speed of 5000 r / min for 10 minutes, pour out the supernatant, repeat the above washing and centrifugation operations 4 times, and transfer the washed modified filler to a vacuum drying oven and dry it at 60 °C for 3 hours to obtain the modified filler.

[0028] Example 3: A highly viscous and stain-resistant acrylate adhesive, comprising the following raw materials in parts by weight: 60 parts of modified acrylate, 7 parts of modified filler, 25 parts of elastomer, 2 parts of initiator, 3 parts of crosslinking agent, 2 parts of plasticizer, and 55 parts of toluene.

[0029] A preparation method of a highly viscous and stain-resistant acrylate adhesive specifically comprises the following steps: S1. In a three-necked flask equipped with a stirring device, a thermometer, and a condenser, add toluene solvent and modified acrylate, turn on the stirring device, control the stirring speed at 250 r / min, slowly add nitrile rubber, and slowly raise the temperature to 65 °C at a rate of 1.5 °C / min, stir until the elastomer is completely dissolved, stop heating and let the solution cool naturally. During the cooling process, keep the stirring speed at 150 r / min until the solution temperature drops to room temperature, and slowly add epoxidized soybean oil, and continue to stir at a speed of 250 r / min for 35 minutes; S2. Divide the dried modified filler into several small portions, add one portion to the reaction kettle every 3 minutes. During the addition of the filler, increase the stirring speed to 350 r / min. After adding each portion of the filler, stir for 17 minutes and then add the next portion; after all the fillers are added, increase the stirring speed to 550 r / min and continue to stir for 1.5 hours; S3. Adjust the stirring speed to 250 r / min, and slowly add diisopropylbenzene peroxide and N,N'-methylenebisacrylamide in sequence. After each additive is added, stir for 7 minutes before adding the next one. Put the well-stirred adhesive solution into a vacuum drying oven, and conduct vacuum degassing at -0.09 MPa and 45 °C for 45 minutes. During this process, ultrasonically treat the solution for 7 minutes every 12 minutes. After the degassing is completed, a highly viscous stain-resistant acrylate adhesive is obtained.

[0030] The modified acrylate contains the following raw materials in parts by weight: 40 parts of ethyl acrylate monomer, 15 parts of 2-hydroxyethyl acrylate, 4 parts of p-toluenesulfonic acid, 60 parts of toluene, 5 parts of perfluorooctylethyl acrylate fluorinated compound, 15 parts of 2,2'-dithiobisethanol, and 3 parts of dibutyltin dilaurate; The specific preparation steps of the modified acrylate are as follows: A1. Place a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser in an oil bath. Turn on the stirrer and stir at a speed of 250 r / min. Under stirring conditions, slowly add the ethyl acrylate monomer and 2-hydroxyethyl acrylate to the three-necked flask in sequence. Slowly raise the temperature of the oil bath to 90 °C. After stirring for 30 minutes, add p-toluenesulfonic acid, and continue the reaction for 1.5 hours. During this period, keep stirring. After the reaction is completed, naturally cool to room temperature to obtain a preliminary modified product; A2. Transfer the preliminary modified product to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. Add toluene solvent to the reaction kettle, turn on the stirrer, and stir at a speed of 350 r / min. Then add perfluorooctylethyl acrylate, raise the temperature of the reaction kettle to 70 °C, keep stirring, and react for 1.5 hours. After the reaction is completed, remove toluene by vacuum distillation at 5 kPa to obtain a secondary modified product; A3. Transfer the secondary modified product to a reaction vessel equipped with a stirrer and a thermometer. Turn on the stirrer and stir at a speed of 250 r / min. Control the temperature of the reaction vessel at 60 °C. Use a constant pressure dropping funnel to add 2,2'-dithiobisethanol to the reaction vessel at a dropping rate of 2 mL per minute. After the dropping is completed, slowly and evenly add dibutyltin dilaurate, and stir and react for 1.5 hours. After the reaction is completed, cool the reaction product to room temperature, filter it with a Buchner funnel and wash it with anhydrous ethanol. Transfer the product to a separatory funnel, add anhydrous ethanol, shake it well and mix, then let it stand for layering, separate the lower organic phase, repeat the washing operation 3 times, and dry it in a drying oven at 85 °C for 1.5 hours to obtain the modified acrylate.

[0031] The modified filler comprises the following raw materials in parts by weight: 70 parts of ethanol, 22 parts of nano-montmorillonite, 11 parts of silane coupling agent KH-570, 3 parts of ammonium polyphosphate, 30 parts of toluene, 11 parts of polydimethylsiloxane, 3 parts of stannous octoate, 30 parts of petroleum ether, 4 parts of hindered amine light stabilizer GW-540, and 4 parts of antioxidant 168; The specific preparation steps of the modified filler are as follows: B1. Pour half of the ethanol solution into a three-necked flask, slowly add nano-montmorillonite to the ethanol solution, set the stirring speed to 350 r / min, and stir for 30 minutes; slowly drop the silane coupling agent KH-570 into the three-necked flask. After the dropping is completed, raise the temperature of the reaction system to 90 °C and continue the reaction for 1.5 hours; after the reaction is completed, centrifuge the product to remove the supernatant, wash the precipitate with anhydrous ethanol 4 times, and finally place the washed product in a vacuum drying oven and dry it to constant weight at 70 °C; B2. Transfer the surface-treated nano-particles to a high-speed mixer, add ammonium polyphosphate, set the stirring speed to 900 r / min, raise the temperature to 70 °C, and continuously stir and mix for 1.5 hours; B3. Add toluene to the reaction kettle, add the above product and polydimethylsiloxane to the reaction kettle, turn on the stirrer, set the stirring speed to 250 r / min, and add stannous octoate as a catalyst. Raise the temperature of the reaction kettle to 60 °C and the reaction time is 1.5 hours. After the reaction is completed, remove the toluene solvent from the product by vacuum distillation at 15 kPa, then wash the product with petroleum ether 4 times, and dry the washed product in a vacuum drying oven at 70 °C for 2.5 hours; B4. Under normal temperature environment, transfer the obtained product to a container with a stirrer. Under the condition of a stirring speed of 150 r / min, sequentially add the hindered amine light stabilizer GW-540 and antioxidant 168 to the container, and continuously stir for 45 minutes; after the stirring is completed, add anhydrous ethanol to the reaction container, continue to stir for 17 minutes, then transfer the mixed solution to a centrifuge tube, put it into a centrifuge, centrifuge at a speed of 4000 r / min for 7 minutes, pour out the supernatant, repeat the above washing and centrifugation operations 3 times, and transfer the washed modified filler to a vacuum drying oven and dry it at 50 °C for 2.5 hours to obtain the modified filler.

[0032] Comparative Example 1 This comparative example is the same as Example 2 except that the modified acrylate is not added.

[0033] Comparative Example 2 This comparative example is the same as Example 2 except that the modified filler is not added.

[0034] Comparative Example 3 This comparative example does not add modified acrylate and modified filler compared with Example 2, and the remaining steps are the same.

[0035] Performance Test Test Method: 1. Adhesion Test: According to the standard of GB / T7124-2008, using a universal material testing machine, the tensile shear strength of the adhesive between metal specimens is measured at a tensile speed of 5 mm / min.

[0036] 2. Stain Resistance Test: Using a contact angle measuring instrument, measure the contact angle of water droplets on the surface of the cured adhesive film. The larger the contact angle, the better the stain resistance.

[0037] 3. High and Low Temperature Resistance Test: Keep the specimen bonded with the adhesive at -50 °C for 2 h, and then at 80 °C for 2 h as a cycle. After 10 cycles, measure the tensile shear strength and calculate the retention rate.

[0038] 4. Flame Retardancy Test: Carry out a vertical burning test according to the UL94 standard to determine the flame retardancy grade of the adhesive.

[0039] 5. Flexibility Test: Repeatedly bend the metal sheet coated with the adhesive, and record the number of bends when cracks or debonding occur.

[0040] 6. Water Resistance Test: Immerse the specimen after curing the adhesive in water for 48 h, take it out and dry the surface moisture, measure the mass before and after immersion, and calculate the water absorption rate according to the formula: Water absorption rate = (mass after immersion - mass before immersion) / mass before immersion × 100%.

[0041] 7. Chemical Resistance Test: Immerse the specimen bonded with the adhesive in a 5% hydrochloric acid solution for 24 h, take it out, wash it, dry it, test the tensile shear strength and calculate the retention rate.

[0042] 8. Chemical Resistance Test: Immerse the specimen bonded with the adhesive in a 5% sodium hydroxide solution for 24 h, take it out, wash it, dry it, test the tensile shear strength and calculate the retention rate.

[0043] 9. Storage Stability Test: Store the adhesive in an environment of 25 °C for 3 months, use a rotational viscometer to test the viscosity before and after storage respectively, and calculate the viscosity change rate according to the formula: Viscosity change rate = (viscosity after storage - viscosity before storage) / viscosity before storage × 100%.

[0044] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Adhesion (tensile shear strength, MPa) 12.5 15.8 14.2 5.3 10.1 8 Stain resistance (contact angle, °) 110 115 112 85 90 75 High and low temperature resistance (retained rate of tensile shear strength after high and low temperature cycling, %) 85 90 88 60 75 50 Flame retardancy (vertical burning rating) V-1 V-0 V-1 No flame retardancy V-2 No flame retardancy Flexibility (number of bending times, times) 150 180 165 80 120 60 Water resistance (water absorption rate, %) 3.5 2.8 3.2 5.5 4.5 7.2 Chemical resistance (retained rate of tensile shear strength after acid corrosion, %) 82 88 85 50 65 40 Chemical resistance (retained rate of tensile shear strength after alkali corrosion, %) 80 86 83 48 62 35 Storage stability (viscosity change rate after 3 months of storage, %) 10 8 9 18 15 23 From the test results, it can be seen that in terms of adhesion, the tensile shear strength of Examples 1-3 far exceeds that of Comparative Examples 1-3. Example 2 shows the most prominent performance, reaching 15.8 MPa, proving that the modified acrylate and modified filler significantly improve the adhesion of the adhesive. While Comparative Example 3, which lacks both of these two components, has an adhesion of only 8 MPa, far lower than that of the examples; in the stain resistance test, the contact angles of the examples are all greater than those of the comparative examples. The contact angle of Example 2 is the largest at 115°, indicating that the surface energy of the modified adhesive is low and the stain resistance performance is good. The contact angle of Comparative Example 3 is only 75°, and its stain resistance is significantly poor; in terms of high and low temperature resistance performance, the retention rate of the tensile shear strength of the examples after high and low temperature cycling is significantly higher than that of the comparative examples. Example 2 reaches 90%, while Comparative Example 3 is only 50%, fully demonstrating that the modified components greatly improve the high and low temperature adaptability of the adhesive; in terms of flame retardancy, Examples 1 and 3 reach V-1 level, and Example 2 even reaches V-0 level, while Comparative Examples 1 and 3 have no flame retardancy rating, and Comparative Example 2 is V-2 level, highlighting the key role of ammonium polyphosphate in the modified filler in improving the flame retardancy performance; in the flexibility test, the number of bending times of the examples is much more than that of the comparative examples. Example 2 performs best with 180 times, while Comparative Example 3 only has 60 times, indicating that the modified adhesive has obvious flexibility advantages; in the water resistance, chemical resistance and storage stability tests, the examples are also superior to the comparative examples. Example 2 performs outstandingly in terms of water resistance, acid resistance and alkali resistance, with a water absorption rate as low as 2.8%. The retention rates of the tensile shear strength after acid and alkali corrosion reach 88% and 86% respectively, and the viscosity change rate after 3 months of storage is only 8%. Comparative Example 3 performs poorly in these aspects, with a water absorption rate as high as 7.2%, and the retention rates of the tensile shear strength after acid and alkali corrosion are 40% and 35% respectively, and the storage stability is also poor, with a viscosity change rate of 23%.

[0045] In summary, the adhesive of the present invention exhibits excellent performance in all aspects. The modified acrylate and modified filler are important factors for improving the comprehensive performance of the adhesive. Since Comparative Example 3 lacks both of these two components, it performs poorly in all performance tests, further confirming its superiority.

[0046] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

Claims

1. A highly viscous and stain-resistant acrylate adhesive, characterized in that: It contains the following raw materials in parts by weight: 50 - 70 parts of modified acrylate, 5 - 10 parts of modified filler, 20 - 30 parts of elastomer, 1 - 3 parts of initiator, 1 - 5 parts of crosslinking agent, 1 - 3 parts of plasticizer, and 40 - 70 parts of toluene.

2. The high-viscosity stain-resistant acrylate adhesive according to claim 1, wherein: The modified acrylate contains the following raw materials in parts by weight: 30 - 50 parts of ethyl acrylate monomer, 10 - 20 parts of 2 - hydroxyethyl acrylate, 3 - 5 parts of p - toluenesulfonic acid, 50 - 70 parts of toluene, 3 - 8 parts of perfluorooctylethyl acrylate, 10 - 20 parts of 2,2'-dithiobisethanol, and 2 - 4 parts of dibutyltin dilaurate; The specific preparation steps of the modified acrylate are as follows: A1. Place a three - necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Start the stirrer and stir at a speed of 200 - 300 r / min. Under stirring conditions, slowly add ethyl acrylate monomer and 2 - hydroxyethyl acrylate to the three - necked flask in sequence. Slowly raise the temperature of the oil bath to 80 - 100 °C, stir for 20 - 40 minutes, then add p - toluenesulfonic acid, and continue the reaction for 1 - 2 hours while continuously stirring. After the reaction ends, naturally cool to room temperature to obtain a preliminary modified product; A2. Transfer the preliminary modified product to a reaction kettle equipped with a stirrer, thermometer, and reflux condenser. Add toluene solvent to the reaction kettle, start the stirrer, and stir at a speed of 300 - 400 r / min. Then add perfluorooctylethyl acrylate, raise the temperature of the reaction kettle to 60 - 80 °C, keep stirring, and react for 1 - 2 hours. After the reaction ends, remove toluene by vacuum distillation at 1 - 10 kPa to obtain a secondary modified product; A3. Transfer the secondary modified product to a reaction vessel equipped with a stirrer and thermometer. Start the stirrer and stir at a speed of 200 - 300 r / min. Control the temperature of the reaction vessel at 50 - 70 °C. Use a constant - pressure dropping funnel to add 2,2'-dithiobisethanol to the reaction vessel at a dropping rate of 1 - 3 mL per minute. After dropping, slowly and evenly add dibutyltin dilaurate, stir and react for 1 - 2 hours. After the reaction ends, cool the reaction product to room temperature, filter it with a Buchner funnel and wash it with anhydrous ethanol. Transfer the product to a separatory funnel, add anhydrous ethanol, shake well and mix, then let it stand for layering, separate the lower organic phase, repeat the washing operation 2 - 4 times, and dry it in a drying oven at 80 - 90 °C for 1 - 2 hours to obtain the modified acrylate.

3. The high-viscosity stain-resistant acrylate adhesive according to claim 1, wherein: The modified filler contains the following raw materials in parts by weight: 60 - 80 parts of ethanol, 15 - 30 parts of nano - montmorillonite, 8 - 15 parts of silane coupling agent KH - 570, 2 - 5 parts of ammonium polyphosphate, 20 - 40 parts of toluene, 8 - 15 parts of polydimethylsiloxane, 1 - 5 parts of stannous octoate, 20 - 40 parts of petroleum ether, 2 - 6 parts of hindered amine light stabilizer GW - 540, and 2 - 6 parts of antioxidant 168; The specific preparation steps of the modified filler are as follows: B1. Pour half of the ethanol solution into a three-necked flask. Slowly add the nano-montmorillonite into the ethanol solution. Set the stirring speed at 300 - 400 r / min and stir for 20 - 40 minutes. Slowly drip the silane coupling agent KH-570 into the three-necked flask. After the dripping is completed, raise the temperature of the reaction system to 80 - 100 °C and continue the reaction for 1 - 2 hours. After the reaction is completed, centrifuge the product to separate, remove the supernatant, and wash the precipitate with anhydrous ethanol 3 - 5 times. Finally, place the washed product in a vacuum drying oven and dry it to a constant weight at 60 - 80 °C. B2. Transfer the surface-treated nano-particles to a high-speed blender, add ammonium polyphosphate, set the stirring speed at 800 - 1000 r / min, raise the temperature to 60 - 80 °C, and continuously stir and mix for 1 - 2 hours. B3. Add toluene to the reaction kettle. Add the above-mentioned modified product and polydimethylsiloxane into the reaction kettle, turn on the stirrer, set the stirring speed at 200 - 300 r / min, and add stannous octoate as a catalyst. Raise the temperature of the reaction kettle to 50 - 70 °C and the reaction time is 1 - 2 hours. After the reaction is completed, remove the toluene solvent from the product by vacuum distillation at 10 - 20 kPa, then wash the product with petroleum ether 3 - 5 times, and dry the washed product in a vacuum drying oven at 60 - 80 °C for 2 - 3 hours. B4. Under normal temperature environment, transfer the obtained product to a container equipped with a stirrer. With the stirring speed at 100 - 200 r / min, sequentially add the hindered amine light stabilizer GW-540 and antioxidant 168 into the container and continuously stir for 30 - 60 minutes. After the stirring is completed, add anhydrous ethanol to the reaction container and continue to stir for 15 - 20 minutes. Then transfer the mixed solution to a centrifuge tube, put it into a centrifuge, centrifuge at a speed of 3000 - 5000 r / min for 5 - 10 minutes, pour out the supernatant, repeat the above washing and centrifugation operations 2 - 4 times, and transfer the washed modified filler to a vacuum drying oven and dry it at 40 - 60 °C for 2 - 3 hours to obtain the modified filler.

4. The high-viscosity stain-resistant acrylate adhesive according to claim 1, wherein: The elastomer is one of nitrile rubber and polyurethane elastomer.

5. The high-viscosity and stain-resistant acrylate adhesive according to claim 1, wherein: The initiator is one of benzoyl peroxide, azobisisobutyronitrile, and dicumyl peroxide.

6. The high-viscosity stain-resistant acrylate adhesive according to claim 1, characterized in that: The cross-linking agent is one of trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, and N,N'-methylenebisacrylamide.

7. The high-viscosity stain-resistant acrylate adhesive according to claim 1, wherein: The plasticizer is one of dioctyl phthalate, dioctyl sebacate, and epoxidized soybean oil.

8. The preparation method of a highly viscous and stain-resistant acrylate adhesive according to claim 1, characterized in that: Specifically, it includes the following steps: S1. In a three-necked flask equipped with a stirring device, a thermometer, and a condenser, add toluene solvent and modified acrylate. Start the stirring device, control the stirring speed at 200 - 300 r / min, slowly add the elastomer, and slowly heat up to 50 - 80 °C at a rate of 1 - 2 °C / min. Stir until the elastomer is completely dissolved, stop heating and let the solution cool naturally. During the cooling process, maintain the stirring speed at 100 - 200 r / min until the solution temperature drops to room temperature. Slowly add the plasticizer and continue to stir at a speed of 200 - 300 r / min for 30 - 40 minutes; S2. Divide the dry modified filler into several small portions and add one portion to the reaction kettle every 2 - 4 minutes. During the addition of the filler, increase the stirring speed to 300 - 400 r / min. After adding each portion of the filler, stir for 15 - 20 minutes and then add the next portion; after all the filler has been added, increase the stirring speed to 500 - 600 r / min and continue to stir for 1 - 2 hours; S3. Adjust the stirring speed to 200 - 300 r / min, and slowly add the initiator and crosslinking agent in sequence. After adding each additive, stir for 5 - 10 minutes before adding the next additive; put the stirred adhesive solution into a vacuum drying oven and conduct vacuum degassing at -0.08 - -0.1 MPa and 40 - 50 °C for 30 - 60 minutes. During this process, ultrasonically treat the solution for 5 - 10 minutes every 10 - 15 minutes. After degassing, a high-viscosity stain-resistant acrylate adhesive is obtained.