Heat-resistant low-viscosity UV adhesive and preparation method thereof
By combining oxocyclobutane-modified castor oil-based polyurethane acrylate with core-shell hydrophobic modified talc filler, the problem of balancing low viscosity and heat resistance in UV adhesives was solved, achieving rapid curing and high-temperature stability, and reducing peel force and high-temperature residue.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-09
- Publication Date
- 2026-04-21
AI Technical Summary
Existing UV adhesives struggle to balance low viscosity and heat resistance. Traditional low-viscosity UV adhesives have low crosslinking density and poor cohesion after curing, making them prone to softening and deformation at high temperatures. Traditional heat-resistant UV adhesives have high viscosity and poor flowability, increasing the difficulty of coating.
A heat-resistant, low-viscosity UV adhesive was prepared by using oxobutane-modified castor oil-based polyurethane acrylate as the main resin, combined with α-hydro-ω-hydroxy polydimethylsiloxane, core-shell hydrophobic modified talc filler, reactive diluent, leveling agent and photoinitiator, and subjected to microwave irradiation treatment.
It achieves rapid curing of low-viscosity UV adhesives, low surface drying energy, high tensile strength, low peel force after UV curing, and no high-temperature residue, thus improving the overall performance of UV adhesives.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of light-curing adhesives, specifically to a heat-resistant, low-viscosity UV adhesive and its preparation method. Background Technology
[0002] With the development of modern industry, the requirements for adhesives are becoming increasingly stringent. This is especially true in fields such as electronics, medical, and optics, where there is a pressing need for adhesives with rapid curing, excellent weather resistance, and low viscosity. Traditional adhesives often suffer from slow curing speeds, poor high-temperature resistance, and high viscosity, failing to meet the specific needs of these fields.
[0003] UV (ultraviolet curing) adhesives are increasingly favored in the adhesive industry due to their high efficiency, energy saving, and environmental friendliness, and their application areas are expanding. However, UV-cured adhesives generally suffer from the challenge of balancing heat resistance and low viscosity. Low-viscosity UV adhesives typically achieve viscosity reduction by adding large amounts of monofunctional reactive diluents or non-reactive diluents. While this meets the requirements for application flowability, the resulting crosslinking density and cohesion are low, making them prone to softening and deformation at high temperatures. Traditional heat-resistant UV adhesives, to ensure heat resistance and mechanical strength, usually employ high-modulus, high-molecular-weight prepolymer systems, resulting in higher viscosity and poorer flowability, increasing the difficulty of coating and application.
[0004] Based on this, the present invention designs a UV adhesive with low viscosity, fast curing and excellent heat resistance and its preparation method to solve the above problems. Summary of the Invention
[0005] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a heat-resistant low-viscosity UV adhesive and its preparation method.
[0006] To achieve the above objectives, the present invention provides the following technical solution: A heat-resistant, low-viscosity UV adhesive, comprising 50-75 parts by weight of oxobutane-modified castor oil-based polyurethane acrylate as the main resin, 3-5 parts by weight of α-hydro-ω-hydroxy polydimethylsiloxane as an additive, and further comprising 18-26 parts by weight of reactive diluent, 1.8-2.3 parts by weight of photoinitiator, 5-11 parts by weight of core-shell hydrophobic modified talc filler, and 0.2-0.4 parts by weight of leveling agent; The oxetane-modified castor oil-based polyurethane acrylate is obtained by prepolymerizing polypropylene glycol, castor oil, and diisocyanate, followed by sequential modification with oxetane monomer and complete end-capping with hydroxyl-containing acrylate; the oxetane monomer used is 3-ethyl-3-hydroxymethyloxetane. The preparation method of the core-shell hydrophobic modified talc filler is as follows: using talc as the core, the talc is modified with vinyltriethoxysilane (VTES), and a Z-type heterojunction composed of TiO2-Bi2WO6-g-C3N4 is added and loaded onto the surface of the talc. A mixed ketoxime silane is added under ultraviolet photocatalysis to undergo a crosslinking reaction. The mixed ketoxime silane is prepared by mixing methyltributanone oxime silane and tetrabutanone oxime silane at a mass ratio of 8-9:1. Finally, microwave irradiation is performed.
[0007] Furthermore, the preparation steps of the oxetane-modified castor oil-based polyurethane acrylate are as follows: Step 1: Under nitrogen protection, mix 5-8 parts by weight of polypropylene glycol and 3-5 parts by weight of castor oil, add 8.5-14 parts by weight of isocyanate and 0.03-0.1 parts by weight of dibutyltin dilaurate, heat to 65-72℃ and react for 2-4 hours to obtain castor oil-based polyurethane prepolymer. Step 2: Slowly add 4-8 parts by weight of oxetane monomer to the above prepolymer. After the addition is complete, place it at 75-85℃ and continue stirring for 3-4 hours. Step 3: Cool the product obtained in the previous step to 55-62℃, add 3.5-6.5 parts by weight of dehydrated hydroxyethyl acrylate to the system, and continue stirring the reaction for 1.5-2.5 hours.
[0008] Furthermore, microwave irradiation with a power of 100-200W and an irradiation time of 40-70s is performed.
[0009] Furthermore, the photoinitiator is a mixture of a free radical photoinitiator and a cationic photoinitiator at a mass ratio of 1:0.2-0.3; the free radical photoinitiator is one or more of photoinitiator 184 and photoinitiator TPO; the cationic photoinitiator is one of diaryliodomonium salt and triarylthiomonium salt.
[0010] Furthermore, the active diluent is TPGDA.
[0011] Furthermore, the specific preparation steps of the core-shell type hydrophobic modified talc filler are as follows: (1) Add talc powder to a 5-8 times its weight of an ethanol-water mixed solution, and ultrasonically disperse it evenly to obtain a talc powder suspension; (2) Add vinyltriethoxysilane (VTES) to the above suspension. The mass ratio of VTES to talc is 1:8-12. Adjust the pH to 4-5.5, heat to 50-62℃ and stir for 1-2 hours to modify the silane surface of the talc to obtain VTES-modified talc suspension. (3) TiO2, Bi2WO6 and g-C3N4 are mixed evenly in a weight ratio of 1-3:2-4:3-5 and calcined at 500-600℃ for 2-3h to prepare a Z-type heterojunction as a photocatalyst. The photocatalyst is added to the VTES modified talc suspension, and the mass ratio of photocatalyst to talc is 1:15-22. The mixture is stirred at a constant temperature of 50-62℃ for 2-3h to load the photocatalyst onto the surface of the VTES modified talc, thus obtaining a photocatalyst-supported VTES modified talc suspension. (4) Under ultraviolet light irradiation with wavelength of 254-365nm and power of 100-200W, add mixed ketoxime silane to the talc powder suspension modified by VTES supported by photocatalyst, and keep the reaction at 50-62℃ for 1-3h. (5) After the product is filtered, washed and dried, it is finally subjected to microwave irradiation with a power of 100-200W and an irradiation time of 40-70s to obtain the final core-shell type hydrophobic modified talc filler.
[0012] Furthermore, in step (5), the product is vacuum filtered, washed 2-3 times with anhydrous ethanol, vacuum dried at 60-80℃ for 8-12 hours, and ground through a 100-200 mesh sieve to obtain core-shell hydrophobic modified talc filler.
[0013] To better achieve the objectives of this invention, this invention also provides a method for preparing the aforementioned heat-resistant, low-viscosity UV adhesive, comprising the following steps: Step 1: Add the main resin, additives and reactive diluent to the reactor, and stir for 15-25 minutes at 25-35℃ and 300-500 r / min to obtain the basic mixture system; Step 2: Add leveling agent to the basic mixing system, and continue stirring for 5-8 minutes at 25-35℃ and 300-500 r / min to ensure uniform dispersion of the additive; Step 3: Slowly add the core-shell type hydrophobic modified talc filler to the above system, stir for 30-40 minutes at a speed of 600-800 r / min, and at the same time use ultrasonic dispersion to make the filler uniformly dispersed in the system without obvious agglomeration. Step 4: Add photoinitiator to the system, reduce the rotation speed to 300-400 r / min, continue stirring for 10-15 min, mix evenly, and then perform vacuum degassing to obtain heat-resistant low-viscosity UV adhesive.
[0014] Furthermore, the ultrasonic dispersion parameters are: power of 200-300W and time of 10-15min.
[0015] To better achieve the objectives of this invention, this invention also provides a heat-resistant, low-viscosity UV adhesive prepared according to the preparation method described above.
[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: The UV protective adhesive prepared according to the embodiments of this invention has advantages such as low surface drying energy, high tensile strength, low peel force after UV treatment, and no high-temperature residue. Specifically, adding a microwave irradiation treatment process during the preparation of the core-shell hydrophobic modified talc filler can improve the curing speed and tensile strength of the UV adhesive and reduce high-temperature residue. The use of core-shell hydrophobic modified talc filler and oxetane-modified castor oil-based polyurethane acrylate can synergistically improve the overall performance of the UV protective adhesive. The core-shell hydrophobic modified talc can reduce the surface polarity of the UV adhesive, reduce the peel force after UV treatment, and improve high-temperature stability, while oxetane modification can improve the crosslinking density and crosslinking uniformity of the resin. The combination of the two has a synergistic effect. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0018] Example 1: A method for preparing a heat-resistant, low-viscosity UV adhesive, comprising the following steps: I. Preparation of oxetane-modified castor oil-based polyurethane acrylate, the specific steps are as follows: Step 1: Under nitrogen protection, 5 parts by weight of polypropylene glycol and 3 parts by weight of castor oil are mixed, 10 parts by weight of isocyanate (IPDI) and 0.03 parts by weight of dibutyltin dilaurate (DBTDL) are added, and the mixture is heated to 65°C and reacted for 4 hours to obtain castor oil-based polyurethane prepolymer. Step 2: Slowly add 4 parts by weight of oxetane monomer (3-ethyl-3-hydroxymethyloxetane) to the above prepolymer. After the addition is complete, place the mixture at 75°C and continue stirring for 4 hours. Step 3: Cool the product obtained in the previous step to 55°C, add 3.5 parts by weight of dehydrated hydroxyethyl acrylate to the system, and continue stirring for 2.5 hours.
[0019] II. Preparation of core-shell type hydrophobic modified talc filler, the specific steps are as follows: (1) Add talc powder to a 5 times its weight of an ethanol-water mixture (volume ratio 1:1), and ultrasonically disperse it evenly to obtain a talc powder suspension; (2) Add vinyltriethoxysilane (VTES) to the above suspension. The mass ratio of VTES to talc is 1:8. Adjust the pH to 4, heat to 50°C and stir for 2 hours to modify the silane surface of talc to obtain VTES-modified talc suspension. (3) TiO2, Bi2WO6 and g-C3N4 were mixed evenly in a weight ratio of 1:2:3 and calcined at 500℃ for 3h to prepare a Z-type heterojunction as a photocatalyst. The photocatalyst was added to the VTES modified talc suspension with a mass ratio of 1:15. The mixture was stirred at 50℃ for 3h to load the photocatalyst onto the surface of the VTES modified talc, thus obtaining a photocatalyst-supported VTES modified talc suspension. (4) Under ultraviolet light irradiation at a wavelength of 254 nm and a power of 100 W, mixed ketoxime silane (prepared by mixing methyl tributanone oxime silane and tetrabutanone oxime silane at a mass ratio of 8:1) was added to the VTES-modified talc powder suspension supported by the photocatalyst, and the reaction was kept at 50 °C for 3 h. (5) The product was vacuum filtered, washed twice with anhydrous ethanol, vacuum dried at 60°C for 12 hours, ground through a 100-mesh sieve, and finally subjected to microwave irradiation with a power of 100W and an irradiation time of 40s to obtain the final core-shell type hydrophobic modified talc filler.
[0020] 3. Add 50 parts by weight of oxetane-modified castor oil-based polyurethane acrylate, 3 parts by weight of α-hydro-ω-hydroxy polydimethylsiloxane and 18 parts by weight of reactive diluent (TPGDA) to the reactor, and stir for 25 minutes at 25°C and 300 r / min to obtain the basic mixed system. 4. Add 0.2 parts by weight of leveling agent (polydimethylsiloxane) to the basic mixing system in sequence, and continue stirring for 8 minutes at 25°C and 300 r / min to ensure uniform dispersion of the additive; 5. Slowly add 5 parts by weight of core-shell hydrophobic modified talc filler to the above system, stir for 40 minutes at a speed of 600 r / min, and simultaneously use 200W ultrasonic dispersion for 15 minutes to ensure that the filler is uniformly dispersed in the system without obvious agglomeration. 6. Add 1.8 parts by weight of photoinitiator to the system (free radical photoinitiator and cationic photoinitiator are compounded at a mass ratio of 1:0.2; the free radical photoinitiator is photoinitiator 184; the cationic photoinitiator is diaryliodonium salt), reduce the speed to 300 r / min, continue stirring for 15 min, and after mixing evenly, perform vacuum degassing treatment to obtain heat-resistant low-viscosity UV adhesive.
[0021] Example 2: A method for preparing a heat-resistant, low-viscosity UV adhesive, comprising the following steps: I. Preparation of oxetane-modified castor oil-based polyurethane acrylate, the specific steps are as follows: Step 1: Under nitrogen protection, 8 parts by weight of polypropylene glycol and 5 parts by weight of castor oil are mixed, 14 parts by weight of isocyanate (IPDI) and 0.1 parts by weight of dibutyltin dilaurate (DBTDL) are added, and the mixture is heated to 72°C and reacted for 2 hours to obtain castor oil-based polyurethane prepolymer. Step 2: Slowly add 8 parts by weight of oxetane monomer (3-ethyl-3-hydroxymethyloxetane) to the above prepolymer. After the addition is complete, place it at 85°C and continue stirring for 3 hours. Step 3: Cool the product obtained in the previous step to 62°C, add 6.5 parts by weight of dehydrated hydroxyethyl acrylate to the system, and continue stirring the reaction for 1.5 hours.
[0022] II. Preparation of core-shell type hydrophobic modified talc filler, the specific steps are as follows: (1) Add talc powder to an ethanol-water mixture (volume ratio 1:1) of 8 times its weight and disperse it evenly by ultrasonication to obtain a talc powder suspension; (2) Add vinyltriethoxysilane (VTES) to the above suspension. The mass ratio of VTES to talc is 1:12. Adjust the pH to 5.5, heat to 62°C and stir for 1 h to modify the silane surface of talc to obtain VTES modified talc suspension. (3) TiO2, Bi2WO6 and g-C3N4 were mixed evenly in a weight ratio of 3:4:5 and calcined at 600℃ for 2h to prepare a Z-type heterojunction as a photocatalyst. The photocatalyst was added to the VTES modified talc suspension with a mass ratio of 1:22. The mixture was stirred at 50℃ for 3h to load the photocatalyst onto the surface of the VTES modified talc, thus obtaining a photocatalyst-supported VTES modified talc suspension. (4) Under ultraviolet light irradiation at a wavelength of 365 nm and a power of 200 W, mixed ketoxime silane (prepared by mixing methyl tributanone oxime silane and tetrabutanone oxime silane at a mass ratio of 9:1) was added to the VTES-modified talc powder suspension supported by the photocatalyst, and the reaction was kept at 62 °C for 1 h. (5) The product was vacuum filtered, washed three times with anhydrous ethanol, vacuum dried at 80°C for 8 hours, ground through a 200-mesh sieve, and finally subjected to microwave irradiation with a power of 200W and an irradiation time of 70s to obtain the final core-shell hydrophobic modified talc filler.
[0023] 3. Add 75 parts by weight of oxobutane-modified castor oil-based polyurethane acrylate, 5 parts by weight of α-hydro-ω-hydroxy polydimethylsiloxane and 26 parts by weight of reactive diluent (TPGDA) to the reactor, and stir for 15 minutes at 35°C and 500 r / min to obtain the basic mixed system. 4. Add 0.4 parts by weight of leveling agent (polydimethylsiloxane) to the basic mixing system in sequence, and continue stirring for 5 minutes at 35°C and 500 r / min to ensure uniform dispersion of the additive; 5. Slowly add 11 parts by weight of core-shell hydrophobic modified talc filler to the above system, stir for 30 minutes at a speed of 800 r / min, and simultaneously use 300W ultrasonic dispersion for 10 minutes to ensure that the filler is uniformly dispersed in the system without obvious agglomeration. 6. Add 2.3 parts by weight of photoinitiator to the system (free radical photoinitiator and cationic photoinitiator are compounded at a mass ratio of 1:0.3; the free radical photoinitiator is photoinitiator TPO; the cationic photoinitiator is triarylsulfonium salt), reduce the speed to 400 r / min, continue stirring for 10 min, and after mixing evenly, perform vacuum degassing treatment to obtain heat-resistant low-viscosity UV adhesive.
[0024] Example 3: A method for preparing a heat-resistant, low-viscosity UV adhesive, comprising the following steps: I. Preparation of oxetane-modified castor oil-based polyurethane acrylate, the specific steps are as follows: Step 1: Under nitrogen protection, 6.5 parts by weight of polypropylene glycol and 4 parts by weight of castor oil are mixed, 8.5 parts by weight of isocyanate (IPDI) and 0.05 parts by weight of dibutyltin dilaurate (DBTDL) are added, and the mixture is heated to 70°C and reacted for 2.5 hours to obtain castor oil-based polyurethane prepolymer. Step 2: Slowly add 6.8 parts by weight of oxetane monomer (3-ethyl-3-hydroxymethyloxetane) to the above prepolymer. After the addition is complete, place the mixture at 80°C and continue stirring for 3.2 hours. Step 3: Cool the product obtained in the previous step to 58°C, add 6 parts by weight of dehydrated hydroxyethyl acrylate to the system, and continue stirring for 2 hours.
[0025] II. Preparation of core-shell type hydrophobic modified talc filler, the specific steps are as follows: (1) Add talc powder to a 6 times its weight of an ethanol-water mixture (volume ratio 1:1), and ultrasonically disperse it evenly to obtain a talc powder suspension; (2) Add vinyltriethoxysilane (VTES) to the above suspension. The mass ratio of VTES to talc is 1:10. Adjust the pH to 4.5, heat to 55°C and stir for 1.6 h to modify the silane surface of talc to obtain VTES-modified talc suspension. (3) TiO2, Bi2WO6 and g-C3N4 were mixed evenly in a weight ratio of 1.5:2.5:4 and calcined at 550℃ for 2.5h to prepare a Z-type heterojunction as a photocatalyst. The photocatalyst was added to the VTES modified talc suspension with a mass ratio of 1:18. The mixture was stirred at a constant temperature of 55℃ for 2.5h to load the photocatalyst onto the surface of the VTES modified talc, thus obtaining a photocatalyst-supported VTES modified talc suspension. (4) Under ultraviolet light irradiation with a wavelength of 300 nm and a power of 150 W, a mixed ketoxime silane (prepared by mixing methyl tributanone oxime silane and tetrabutanone oxime silane at a mass ratio of 8.5:1) was added to the VTES-modified talc powder suspension supported by the photocatalyst, and the reaction was kept at 55 °C for 2 h. (5) The product was vacuum filtered, washed three times with anhydrous ethanol, vacuum dried at 70°C for 11 hours, ground through a 200-mesh sieve, and finally subjected to microwave irradiation with a power of 180W and an irradiation time of 60s to obtain the final core-shell type hydrophobic modified talc filler.
[0026] 3. Add 55 parts by weight of oxobutane-modified castor oil-based polyurethane acrylate, 4 parts by weight of α-hydro-ω-hydroxy polydimethylsiloxane and 20 parts by weight of reactive diluent (TPGDA) to the reactor, and stir for 20 minutes at 30°C and 400 r / min to obtain the basic mixed system. 4. Add 0.3 parts by weight of leveling agent (polydimethylsiloxane) to the basic mixing system in sequence, and continue stirring for 7 minutes at 30°C and 420 r / min to ensure uniform dispersion of the additive; 5. Slowly add 8 parts by weight of core-shell hydrophobic modified talc filler to the above system, stir for 35 minutes at a speed of 700 r / min, and simultaneously use 250W ultrasonic dispersion for 12 minutes to ensure that the filler is uniformly dispersed in the system without obvious agglomeration. 6. Add 2 parts by weight of photoinitiator to the system (free radical photoinitiator and cationic photoinitiator are compounded at a mass ratio of 1:0.25; the free radical photoinitiator is photoinitiator 184; the cationic photoinitiator is triarylsulfonium salt), reduce the speed to 350 r / min, continue stirring for 12 min, and after mixing evenly, perform vacuum degassing treatment to obtain heat-resistant low-viscosity UV adhesive.
[0027] Comparative Example 1: Unlike Example 3, the final microwave irradiation treatment process was omitted in the preparation of core-shell hydrophobic modified talc filler.
[0028] Comparative Example 2: Unlike Example 3, the core-shell hydrophobic modified talc filler was replaced with unmodified talc filler.
[0029] Comparative Example 3: Unlike Example 3, the oxetane-modified castor oil-based polyurethane acrylate was replaced with castor oil-based polyurethane acrylate.
[0030] The preparation method of castor oil-based polyurethane acrylate is as follows: Under nitrogen protection, 6.5 parts by weight of polypropylene glycol, 4 parts by weight of castor oil, 8.5 parts by weight of isocyanate (IPDI), and 0.05 parts by weight of dibutyltin dilaurate (DBTDL) are heated to 70°C and reacted for 2.5 h to obtain castor oil-based polyurethane prepolymer; the obtained product is cooled to 58°C, and 6 parts by weight of dehydrated hydroxyethyl acrylate is added to the system, and the reaction is continued to be stirred for 2 h.
[0031] Comparative Example 4: Unlike Example 3, the core-shell hydrophobic modified talc filler was replaced with unmodified talc filler. Simultaneously, the oxetane-modified castor oil-based polyurethane acrylate was replaced with castor oil-based polyurethane acrylate.
[0032] Experimental Example: The following performance tests were performed on the UV protective adhesives prepared in Examples 1-3 and Comparative Examples 1-4: 1. Curing speed test: The coating is about 20 micrometers thick, cured by a 365nm LED lamp, and the UV lamp irradiation power is 200mW / cm2. The curing energy is tested by a four-channel energy meter. It is considered to be surface dry when it is no longer sticky to the touch.
[0033] 2. Tensile strength and elongation at break test: The rubber strip was made using a dumbbell-shaped mold type 2, cured with a 365nm LED lamp, with a UV lamp irradiation power of 200mW / cm2 and a curing energy of 2000mJ / cm2. It was then tested with a universal tensile testing machine at 300mm / min.
[0034] 3. Peel strength before and after UV treatment and high-temperature residue: Apply UV adhesive to the surface to be protected and test the peel strength before UV treatment. Then place it in an oven at 200℃ for 30 minutes and test whether there is any residue after peeling. Finally, cure it with a 365nm LED lamp and test the peel strength after UV treatment.
[0035] The results are shown in Table 1.
[0036] Table 1 Performance Tests of UV Protective Adhesive
[0037] As shown in Table 1, the UV protective adhesives prepared in Examples 1-3 of this invention have lower surface drying energy, higher tensile strength, lower peel strength after UV treatment, and no high-temperature residue compared to the UV protective adhesives prepared in Comparative Examples 1-4. Specifically, adding a microwave irradiation treatment process during the preparation of the core-shell hydrophobic modified talc filler can improve the curing speed and tensile strength of the UV adhesive and reduce high-temperature residue. The use of core-shell hydrophobic modified talc filler and oxetane-modified castor oil-based polyurethane acrylate can synergistically improve the overall performance of the UV protective adhesive. The core-shell hydrophobic modified talc can reduce the surface polarity of the UV adhesive, reduce the peel strength after UV treatment, and improve high-temperature stability, while oxetane modification can improve the crosslinking density and crosslinking uniformity of the resin. The combination of these two technologies has a synergistic effect.
[0038] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A heat-resistant, low-viscosity UV adhesive, characterized in that, The main resin is 50-75 parts by weight of oxobutane-modified castor oil-based polyurethane acrylate, with 3-5 parts by weight of α-hydro-ω-hydroxy polydimethylsiloxane as an additive, and also includes 18-26 parts by weight of reactive diluent, 1.8-2.3 parts by weight of photoinitiator, 5-11 parts by weight of core-shell hydrophobic modified talc filler and 0.2-0.4 parts by weight of leveling agent; The oxetane-modified castor oil-based polyurethane acrylate is obtained by prepolymerizing polypropylene glycol, castor oil, and diisocyanate, followed by sequential modification with oxetane monomer and complete end-capping with hydroxyl-containing acrylate; the oxetane monomer used is 3-ethyl-3-hydroxymethyloxetane. The preparation method of the core-shell hydrophobic modified talc filler is as follows: using talc as the core, the talc is modified with vinyltriethoxysilane (VTES), and a Z-type heterojunction composed of TiO2-Bi2WO6-g-C3N4 is added and loaded onto the surface of the talc. A mixed ketoxime silane is added under ultraviolet light catalysis to undergo a crosslinking reaction. The mixed ketoxime silane is prepared by mixing methyl tributanone oxime silane and tetrabutanone oxime silane at a mass ratio of 8-9:
1. Finally, microwave irradiation is performed.
2. The heat-resistant, low-viscosity UV adhesive according to claim 1, characterized in that, The preparation steps of the oxetane-modified castor oil-based polyurethane acrylate are as follows: Step 1: Under nitrogen protection, mix 5-8 parts by weight of polypropylene glycol and 3-5 parts by weight of castor oil, add 8.5-14 parts by weight of isocyanate and 0.03-0.1 parts by weight of dibutyltin dilaurate, heat to 65-72℃ and react for 2-4 hours to obtain castor oil-based polyurethane prepolymer. Step 2: Slowly add 4-8 parts by weight of oxetane monomer to the above prepolymer. After the addition is complete, place it at 75-85℃ and continue stirring for 3-4 hours. Step 3: Cool the product obtained in the previous step to 55-62℃, add 3.5-6.5 parts by weight of dehydrated hydroxyethyl acrylate to the system, and continue stirring the reaction for 1.5-2.5 hours.
3. The heat-resistant, low-viscosity UV adhesive according to claim 2, characterized in that, Finally, microwave irradiation with a power of 100-200W and an irradiation time of 40-70s is performed.
4. The heat-resistant, low-viscosity UV adhesive according to claim 3, characterized in that, The photoinitiator is a mixture of a free radical photoinitiator and a cationic photoinitiator at a mass ratio of 1:0.2-0.3; the free radical photoinitiator is one or more of photoinitiator 184 and photoinitiator TPO; the cationic photoinitiator is one of diaryliodomonium salt and triarylthiomonium salt.
5. The heat-resistant, low-viscosity UV adhesive according to claim 4, characterized in that, The active diluent used is TPGDA.
6. The heat-resistant, low-viscosity UV adhesive according to claim 5, characterized in that, The specific preparation steps of the core-shell type hydrophobic modified talc filler are as follows: (1) Add talc powder to a 5-8 times its weight of an ethanol-water mixed solution, and ultrasonically disperse it evenly to obtain a talc powder suspension; (2) Add vinyltriethoxysilane (VTES) to the above suspension. The mass ratio of VTES to talc is 1:8-12. Adjust the pH to 4-5.5, heat to 50-62℃ and stir for 1-2 hours to modify the silane surface of the talc to obtain VTES-modified talc suspension. (3) TiO2, Bi2WO6 and g-C3N4 are mixed evenly in a weight ratio of 1-3:2-4:3-5 and calcined at 500-600℃ for 2-3h to prepare a Z-type heterojunction as a photocatalyst. The photocatalyst is added to the VTES modified talc suspension, and the mass ratio of photocatalyst to talc is 1:15-22. The mixture is stirred at a constant temperature of 50-62℃ for 2-3h to load the photocatalyst onto the surface of the VTES modified talc, thus obtaining a photocatalyst-supported VTES modified talc suspension. (4) Under ultraviolet light irradiation with wavelength of 254-365nm and power of 100-200W, add mixed ketoxime silane to the talc powder suspension modified by VTES supported by photocatalyst, and keep the reaction at 50-62℃ for 1-3h. (5) After the product is filtered, washed and dried, it is finally subjected to microwave irradiation with a power of 100-200W and an irradiation time of 40-70s to obtain the final core-shell type hydrophobic modified talc filler.
7. The heat-resistant, low-viscosity UV adhesive according to claim 6, characterized in that, In step (5), the product is vacuum filtered, washed 2-3 times with anhydrous ethanol, vacuum dried at 60-80℃ for 8-12 hours, and ground through a 100-200 mesh sieve to obtain core-shell hydrophobic modified talc filler.
8. A method for preparing a heat-resistant, low-viscosity UV adhesive according to claim 7, characterized in that, Includes the following steps: Step 1: Add the main resin, additives and reactive diluent to the reactor, and stir for 15-25 minutes at 25-35℃ and 300-500 r / min to obtain the basic mixture system; Step 2: Add leveling agent to the basic mixing system, and continue stirring for 5-8 minutes at 25-35℃ and 300-500 r / min to ensure uniform dispersion of the additive; Step 3: Slowly add the core-shell type hydrophobic modified talc filler to the above system, stir for 30-40 minutes at a speed of 600-800 r / min, and at the same time use ultrasonic dispersion to make the filler uniformly dispersed in the system without obvious agglomeration. Step 4: Add photoinitiator to the system, reduce the rotation speed to 300-400 r / min, continue stirring for 10-15 min, mix evenly, and then perform vacuum degassing to obtain heat-resistant low-viscosity UV adhesive.
9. The method for preparing the heat-resistant, low-viscosity UV adhesive according to claim 8, characterized in that, Ultrasonic dispersion parameters: power 200-300W, time 10-15min.
10. A heat-resistant, low-viscosity UV adhesive prepared by the preparation method according to claim 9.