Water-based acrylic acid adhesive and preparation method thereof

Abstract

The invention discloses a water-based acrylic adhesive and a preparation method thereof, and relates to the technical field of adhesives. When the water-based acrylic acid adhesive is prepared, firstly, polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylic acid, N, N-bis (2-ethoxyl) aminomethylene diethyl phosphonate, polyethylene glycol and ethidene diamine are used as raw materials, and a polyurethane acrylate emulsion is prepared through polymerization, chain extension and emulsification; secondly, vinyl boric acid and m-digallic acid react to synthesize vinyl gallic acid borate, and then vinyl gallic acid borate, butyl acrylate, methyl methacrylate, 2, 2, 3, 3, 3-pentafluoropropyl acrylate and other monomers are subjected to emulsion copolymerization to prepare water-based polyacrylate; and finally, mixing the polyurethane acrylate emulsion, the water-based polyacrylate and a photoinitiator to prepare the water-based acrylic acid adhesive. The water-based acrylic acid adhesive prepared by the preparation method disclosed by the invention has excellent adhesive property, water resistance, flame retardance and oxidation resistance.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a water-based acrylic adhesive and its preparation method. Background Technology

[0002] Waterborne acrylic adhesives, with their excellent bonding properties, outstanding transparency, and weather resistance, have become key materials in packaging printing, textile lamination, automotive interiors, and electronic component assembly. While traditional solvent-based products offer good performance, they release large amounts of volatile organic compounds during production and application, leading to environmental pollution and potential health risks. Conventional waterborne acrylic adhesives, while overcoming environmental concerns, often have limitations in water resistance, initial tack, flame retardancy, and applicability to various substrates, making it difficult to fully meet the stringent comprehensive performance requirements of high-end manufacturing or demanding application environments.

[0003] In recent years, global environmental regulations have continued to tighten, and the market demand for green, efficient, and multifunctional materials has become increasingly urgent. Therefore, industry research and development has focused on overcoming the performance bottlenecks of existing waterborne adhesives through innovative resin structure design, the introduction of functional monomers, and composite modification technologies. Developing a waterborne acrylic adhesive that can simultaneously achieve low organic compound emissions, rapid curing, strong and durable bonding, and also possess good water resistance and flame retardancy is of significant practical importance for promoting industrial upgrading and meeting the needs of sustainable development. Summary of the Invention

[0004] The purpose of this invention is to provide a water-based acrylic adhesive and its preparation method to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A water-based acrylic adhesive, wherein the water-based acrylic adhesive is prepared by mixing polyurethane acrylate emulsion, water-based polyacrylate and photoinitiator.

[0006] As an optimization, the polyurethane acrylate emulsion is prepared by polymerization, chain extension and emulsification of polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, polyethylene glycol and ethylenediamine.

[0007] As an optimization, the aqueous polyacrylate is prepared by emulsion copolymerization of butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid and vinyl gallate borate.

[0008] As an optimization, the vinyl gallate borate is prepared by reacting vinyl boric acid with meta-bisgallic acid.

[0009] A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh out polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol in a molar ratio of 1:(2.95~2.98):(0.48~0.52):(0.57~0.6):(0.17~0.19):(0.57~0.6):(0.59~0.6). Under a nitrogen atmosphere, mix polyether glycol and isophorone diisocyanate evenly, add 0.02%~0.05% of stannous octoate by weight of polyether glycol, and reflux and stir for 1.5 minutes at 85~90℃ and 300~500 r / min. After 2.5 hours, add bisphenol A glycerol diacrylate and N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester and continue stirring for 1-2 hours. Cool down to 55-65℃, add polyethylene glycol and continue stirring for 2.5-3.5 hours. Cool down to 25-35℃, add ethylenediamine and acetone at 0.7-0.8 times the mass of polyether glycol and continue stirring for 0.5-1.5 hours. Add deionized water at 5-5.5 times the mass of polyether glycol and stir at 2500-3000 r / min for 0.5-1.5 hours. Add anhydrous ethanol and continue stirring for 10-20 minutes. Distill under reduced pressure until the emulsion solid content is 25%-30% to obtain a polyurethane acrylate emulsion. (2) Weigh vinyl boric acid and m-bis-gallic acid in a molar ratio of 1:1. Under a nitrogen atmosphere, mix m-bis-gallic acid and anhydrous tetrahydrofuran in a mass ratio of 1:(45~55). Stir at 25~30℃ and 300~500r / min until completely dissolved. Add 10wt%~15wt% anhydrous tetrahydrofuran solution of vinyl boric acid dropwise. After the addition is complete, add anhydrous magnesium sulfate at a mass ratio of 4~5 times that of m-bis-gallic acid. Continue stirring for 2~3h. Filter and concentrate under reduced pressure to obtain vinyl gallate borate. Weigh the following raw materials in the following mass parts: 80~90 parts butyl acrylate, 18~22 parts methyl methacrylate, 3~7 parts vinyl gallate borate, 2~4 parts acrylic acid, 7~9 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2~3 parts sodium dodecyl sulfate, 1~2 parts alkylphenol polyoxyethylene ether, and ammonium persulfate. 0.5-0.8 parts of deionized water and 115-125 parts of deionized water were mixed and dissolved with 65-75 parts of deionized water, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether. Butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid and vinyl gallate borate were added sequentially. The mixture was emulsified at 25-30°C and 2500-3000 r / min for 10-20 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion and 1 / 3 of the ammonium persulfate were mixed and stirred at 65-75°C and 300-500 r / min for 15-25 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 1.5-2.5 h. After the addition was complete, the temperature was raised to 80-90°C and stirring was continued for 1-1.5 h. The mixture was cooled and the pH was adjusted to 5.5-6 with 0.1M hydrochloric acid to obtain an aqueous polyacrylate. (3) Mix waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator at a mass ratio of 1:(0.15~0.25):(0.0001~0.0002) and stir at 25~30℃ and 300~500r / min for 25~35min to obtain waterborne acrylic adhesive.

[0010] As an optimization, the polyether glycol in step (1) is of type N210; the polyethylene glycol is polyethylene glycol 2000.

[0011] As an optimization, the polyurethane acrylate emulsion reaction process in step (1) is as follows: .

[0012] As an optimization, the aqueous polyacrylate reaction process in step (2) is as follows: .

[0013] As an optimization, the photoinitiator in step (3) is photoinitiator 2959.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing the waterborne acrylic adhesive, this invention first uses polyether glycol, isophorone diisocyanate, bisphenol A glyceryl diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, polyethylene glycol, and ethylenediamine as raw materials, and obtains a polyurethane acrylate emulsion through polymerization, chain extension, and emulsification. Next, vinyl gallate borate is synthesized by reacting vinyl borate with m-bisgallic acid, and then this is copolymerized with monomers such as butyl acrylate, methyl methacrylate, and 2,2,3,3,3-pentafluoropropyl acrylate through emulsion copolymerization to prepare a waterborne polyacrylate. Finally, the polyurethane acrylate emulsion, the waterborne polyacrylate, and a photoinitiator are mixed to obtain the waterborne acrylic adhesive.

[0015] First, in the synthesis of polyurethane acrylate emulsion, a flexible molecular chain is constructed using polyether glycol as the soft segment and isophorone diisocyanate and chain extender as the hard segment. Bisphenol A glycerol diacrylate is introduced to introduce photocurable acrylate groups. The introduction of diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate simultaneously provides phosphorus-based flame retardant elements and tertiary amine basic sites. Its phosphonate structure decomposes at high temperature, which can promote char formation and improve the flame retardant performance of the adhesive layer, while the tertiary amine group provides key reaction sites for subsequent mixing. Ethylenediamine chain extension further enhances the stability and cohesive strength of the emulsion.

[0016] Secondly, vinyl gallate borate retains the phenolic hydroxyl and carboxyl groups derived from gallic acid. When copolymerized with butyl acrylate, methyl methacrylate, and fluorinated monomers, it not only introduces carboxyl groups and dynamic borate bonds into the polymer chain, but also endows the system with excellent antioxidant capabilities, effectively capturing free radicals and delaying adhesive aging. When polyurethane acrylate emulsions are mixed with aqueous polyacrylates, the polyurethane acrylate emulsion acts as a multifunctional crosslinking agent. The slightly acidic environment promotes acid-base neutralization between the tertiary amines and carboxyl groups on the polyurethane chain, forming ionic bonds and constructing a preliminary physical crosslinking network. Subsequently, under high temperature and ultraviolet light irradiation, the acrylate double bonds undergo covalent crosslinking, ultimately forming a multi-layered network with synergistic ionic, dynamic borate, and permanent covalent bonds. This structure significantly improves the tensile strength, water resistance, and durability of the adhesive. The antioxidant effect of the phenolic hydroxyl groups, combined with the synergistic effect of phosphorus-nitrogen and fluorinated monomers, further endows the material with good anti-aging, flame retardant, and chemical resistance properties. Attached Figure Description

[0017] Figure 1 Thermogravimetric analysis (TGA) spectra of the UV-cured waterborne acrylic adhesives prepared in Examples 2 and 4-5 are shown.

[0018] Figure 2The differential thermogravimetric (DTG) spectra are those of the UV-cured waterborne acrylic adhesives prepared in Examples 2 and 4-5. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] To more clearly illustrate the method provided by the present invention, the following embodiments will be described in detail.

[0021] Example 1: A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh out polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol in a molar ratio of 1:2.95:0.48:0.57:0.17:0.57:0.59. Under a nitrogen atmosphere, mix polyether glycol and isophorone diisocyanate evenly, add 0.02% stannous octoate by weight of polyether glycol, reflux and stir at 85°C and 300 r / min for 1.5 h, then add... Bisphenol A glycerol diacrylate and N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester were stirred for 1 hour, cooled to 55°C, polyethylene glycol was added and stirred for 2.5 hours, cooled to 25°C, ethylenediamine and acetone (0.7 times the mass of polyether glycol) were added and stirred for 0.5 hours, deionized water (5 times the mass of polyether glycol) was added, and stirred at 2500 r / min for 0.5 hours. Anhydrous ethanol was added and stirred for 10 minutes. The mixture was then distilled under reduced pressure until the solid content of the emulsion was 25%, thus obtaining a polyurethane acrylate emulsion. (2) Weigh vinyl boric acid and m-bis-gallic acid in a molar ratio of 1:1. Under a nitrogen atmosphere, mix m-bis-gallic acid and anhydrous tetrahydrofuran in a mass ratio of 1:45. Stir at 25°C and 300 r / min until completely dissolved. Add 10 wt% anhydrous tetrahydrofuran solution of vinyl boric acid dropwise. After the addition is complete, add anhydrous magnesium sulfate with a mass of 4 times that of m-bis-gallic acid. Continue stirring for 2 hours. Filter and concentrate under reduced pressure to obtain vinyl gallate borate. Weigh the raw materials according to the following mass parts: 80 parts butyl acrylate, 18 parts methyl methacrylate, 3 parts vinyl gallate borate, 2 parts acrylic acid, 7 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2 parts sodium dodecyl sulfate, and 1 part alkylphenol polyoxyethylene ether. 0.5 parts ammonium persulfate and 115 parts deionized water were mixed and dissolved with 65 parts deionized water, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether. Butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid, and vinyl gallate borate were added sequentially. The mixture was emulsified at 25°C and 2500 rpm for 10 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion, and 1 / 3 of the ammonium persulfate were mixed and stirred at 65°C and 300 rpm for 15 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 1.5 h. After the addition was complete, the temperature was raised to 80°C and stirring was continued for 1 h. The mixture was then cooled and the pH was adjusted to 5.5 with 0.1 M hydrochloric acid to obtain an aqueous polyacrylate. (3) A water-based acrylic ester, polyurethane acrylate emulsion and photoinitiator are mixed at a mass ratio of 1:0.2:0.0001 and stirred at 25°C and 300r / min for 25min to obtain a water-based acrylic adhesive.

[0022] Example 2: A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh out polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol in a molar ratio of 1:2.97:0.5:0.58:0.18:0.59:0.59. Under a nitrogen atmosphere, mix polyether glycol and isophorone diisocyanate evenly, add 0.04% of stannous octoate by mass of polyether glycol, reflux and stir at 87℃ and 400 r / min for 2 h, then add bisphenol A glycerol diacrylate diacrylate. Phenolic A glycerol diacrylate and N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester were stirred for 1.5 h, cooled to 60 °C, polyethylene glycol was added and stirred for 3 h, cooled to 30 °C, ethylenediamine and acetone (0.75 times the mass of polyether glycol) were added and stirred for 1 h, deionized water (5.5 times the mass of polyether glycol) was added and stirred at 2700 r / min for 1 h, anhydrous ethanol was added and stirred for 15 min, and the emulsion was distilled under reduced pressure until the solid content of the emulsion was 27%, thus obtaining a polyurethane acrylate emulsion. (2) Weigh vinylboric acid and m-bis-gallic acid in a molar ratio of 1:1. Under a nitrogen atmosphere, mix m-bis-gallic acid and anhydrous tetrahydrofuran at a mass ratio of 1:50. Stir at 27°C and 400 r / min until completely dissolved. Add 13 wt% anhydrous tetrahydrofuran solution of vinylboric acid dropwise. After the addition is complete, add anhydrous magnesium sulfate at a mass ratio of 4.5 times that of m-bis-gallic acid. Continue stirring for 2.5 h. Filter and concentrate under reduced pressure to obtain vinyl gallate borate. Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 5 parts vinyl gallate borate, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, and 1 part alkylphenol polyoxyethylene ether. 0.5 parts of ammonium persulfate, 0.7 parts of deionized water, 120 parts of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether were mixed and dissolved. Butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid and vinyl gallate borate were added sequentially. The mixture was emulsified at 27°C and 2700 r / min for 15 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion and 1 / 3 of the ammonium persulfate were mixed and stirred at 70°C and 400 r / min for 20 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 2 h. After the addition was complete, the temperature was raised to 85°C and stirring was continued for 1.5 h. After cooling, the pH was adjusted to 5.7 with 0.1M hydrochloric acid to obtain an aqueous polyacrylate. (3) A water-based acrylic ester, polyurethane acrylate emulsion and photoinitiator are mixed at a mass ratio of 1:0.2:0.00015 and stirred at 27°C and 400r / min for 30min to obtain a water-based acrylic adhesive.

[0023] Example 3: A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh out polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol in a molar ratio of 1:2.98:0.52:0.6:0.19:0.6. Under a nitrogen atmosphere, mix polyether glycol and isophorone diisocyanate evenly, add 0.05% of polyether glycol by weight of stannous octoate, reflux and stir at 90℃ and 500 r / min for 2.5 h, then add bisphenol A. A. Glyceryl diacrylate and N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester were stirred for 2 hours, cooled to 65°C, polyethylene glycol was added and stirred for 3.5 hours, cooled to 35°C, ethylenediamine and acetone (0.8 times the mass of polyether glycol) were added and stirred for 1.5 hours, deionized water (5.5 times the mass of polyether glycol) was added, and the mixture was stirred at 3000 r / min for 1.5 hours. Anhydrous ethanol was added and the mixture was stirred for 20 minutes. The mixture was then distilled under reduced pressure until the solid content of the emulsion was 30%, thus obtaining a polyurethane acrylate emulsion. (2) Weigh vinyl boric acid and m-bis-gallic acid in a molar ratio of 1:1. Under a nitrogen atmosphere, mix m-bis-gallic acid and anhydrous tetrahydrofuran in a mass ratio of 1:55. Stir at 30°C and 500 r / min until completely dissolved. Add 15 wt% anhydrous tetrahydrofuran solution of vinyl boric acid dropwise. After the addition is complete, add anhydrous magnesium sulfate at a mass ratio of 5 times that of m-bis-gallic acid. Continue stirring for 3 hours. Filter and concentrate under reduced pressure to obtain vinyl gallate borate. Weigh the raw materials according to the following mass parts: 90 parts butyl acrylate, 22 parts methyl methacrylate, 7 parts vinyl gallate borate, 4 parts acrylic acid, 9 parts 2,2,3,3,3-pentafluoropropyl acrylate, 3 parts sodium dodecyl sulfate, and 2 parts alkylphenol polyoxyethylene ether. 0.8 parts ammonium persulfate and 125 parts deionized water were mixed and dissolved with 75 parts deionized water, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether. Butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid, and vinyl gallate borate were added sequentially. The mixture was emulsified at 30°C and 3000 rpm for 20 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion, and 1 / 3 of the ammonium persulfate were mixed and stirred at 75°C and 500 rpm for 25 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 2.5 h. After the addition was complete, the temperature was raised to 90°C and stirring was continued for 1.5 h. After cooling, the pH was adjusted to 6 with 0.1 M hydrochloric acid to obtain an aqueous polyacrylate. (3) Aqueous polyacrylate, polyurethane acrylate emulsion and photoinitiator are mixed at a mass ratio of 1:0.2:0.0002 and stirred at 30°C and 500r / min for 35min to obtain aqueous acrylic adhesive.

[0024] Example 4: The difference from Example 2 lies only in step (2). The original text, "Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 5 parts vinyl gallate borate, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, 1.5 parts alkylphenol polyoxyethylene ether, 0.7 parts ammonium persulfate, and 120 parts deionized water", is changed to "Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 3 parts vinyl gallate borate, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, 1.5 parts alkylphenol polyoxyethylene ether, 0.7 parts ammonium persulfate, and 120 parts deionized water".

[0025] Example 5: The difference from Example 2 lies only in step (2). The original text, "Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 5 parts vinyl gallate borate, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, 1.5 parts alkylphenol polyoxyethylene ether, 0.7 parts ammonium persulfate, and 120 parts deionized water", is changed to "Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 7 parts vinyl gallate borate, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, 1.5 parts alkylphenol polyoxyethylene ether, 0.7 parts ammonium persulfate, and 120 parts deionized water".

[0026] Comparative Example 1: The only difference from Example 2 is step (3), which changes "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.2:0.00015" to "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.1:0.00015".

[0027] Comparative Example 2: The only difference from Example 2 is step (3), which changes "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.2:0.0002" to "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.15:0.0002".

[0028] Comparative Example 3: The only difference from Example 2 is step (3), which changes "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.2:0.00015" to "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.25:0.00015".

[0029] Comparative Example 4: The only difference from Example 2 is the step (3), which changes "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.2:0.00015" to "mixing waterborne polyacrylate, polyurethane acrylate emulsion and photoinitiator in a mass ratio of 1:0.3:0.00015".

[0030] Comparative Example 5: The only difference from Example 2 is step (1), in which “N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester” is replaced with an equimolar amount of “methyldiethanolamine”.

[0031] Comparative Example 6: A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh out polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol in a molar ratio of 1:2.97:0.5:0.58:0.18:0.59:0.59. Under a nitrogen atmosphere, mix polyether glycol and isophorone diisocyanate evenly, add 0.04% of stannous octoate by mass of polyether glycol, reflux and stir at 87℃ and 400 r / min for 2 h, then add bisphenol A glycerol diacrylate diacrylate. Phenolic A glycerol diacrylate and N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester were stirred for 1.5 h, cooled to 60 °C, polyethylene glycol was added and stirred for 3 h, cooled to 30 °C, ethylenediamine and acetone (0.75 times the mass of polyether glycol) were added and stirred for 1 h, deionized water (5.5 times the mass of polyether glycol) was added and stirred at 2700 r / min for 1 h, anhydrous ethanol was added and stirred for 15 min, and the emulsion was distilled under reduced pressure until the solid content of the emulsion was 27%, thus obtaining a polyurethane acrylate emulsion. (2) Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 5 parts 4-vinylbenzoic acid, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, 1.5 parts alkylphenol polyoxyethylene ether, 0.7 parts ammonium persulfate, and 120 parts deionized water. Mix and dissolve 70 parts deionized water, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether, and then add butyl acrylate and methyl methacrylate in sequence. 2,2,3,3,3-Pentafluoropropyl acrylate, acrylic acid, and 4-vinylbenzoic acid were emulsified at 27°C and 2700 rpm for 15 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion, and 1 / 3 of the ammonium persulfate were mixed and stirred at 70°C and 400 rpm for 20 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 2 h. After the addition was complete, the temperature was raised to 85°C and stirring was continued for 1.5 h. After cooling, water-based polyacrylate was obtained. (3) A water-based acrylic ester, polyurethane acrylate emulsion and photoinitiator are mixed at a mass ratio of 1:0.2:0.00015 and stirred at 27°C and 400r / min for 30min to obtain a water-based acrylic adhesive.

[0032] Comparative Example 7: A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh out polyether glycol, isophorone diisocyanate, bisphenol A glycerol diacrylate, N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol in a molar ratio of 1:2.97:0.5:0.58:0.18:0.59:0.59. Under a nitrogen atmosphere, mix polyether glycol and isophorone diisocyanate evenly, add 0.04% of stannous octoate by mass of polyether glycol, reflux and stir at 87℃ and 400 r / min for 2 h, then add bisphenol A glycerol diacrylate diacrylate. Phenolic A glycerol diacrylate and N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester were stirred for 1.5 h, cooled to 60 °C, polyethylene glycol was added and stirred for 3 h, cooled to 30 °C, ethylenediamine and acetone (0.75 times the mass of polyether glycol) were added and stirred for 1 h, deionized water (5.5 times the mass of polyether glycol) was added and stirred at 2700 r / min for 1 h, anhydrous ethanol was added and stirred for 15 min, and the emulsion was distilled under reduced pressure until the solid content of the emulsion was 27%, thus obtaining a polyurethane acrylate emulsion. (2) Weigh vinyl boric acid and meta-bisgallic acid in a molar ratio of 1:1. Under a nitrogen atmosphere, mix meta-bisgallic acid and anhydrous tetrahydrofuran in a mass ratio of 1:50. Stir at 27°C and 400 r / min until completely dissolved. Add 13 wt% anhydrous tetrahydrofuran solution of vinyl boric acid dropwise. After the addition is complete, add anhydrous magnesium sulfate at a mass ratio of 4.5 times that of meta-bisgallic acid. Continue stirring for 2.5 h. Filter and concentrate under reduced pressure to obtain vinyl gallate borate. Weigh the raw materials according to the following mass parts: 94 parts butyl acrylate, 20 parts methyl methacrylate, 5 parts vinyl gallate borate, 3 parts acrylic acid, 2.5 parts sodium dodecyl sulfate, and 1 part alkylphenol polyoxyethylene ether. 5 parts of ammonium persulfate, 0.7 parts of sodium dodecyl sulfate, and 120 parts of deionized water were mixed and dissolved with 70 parts of deionized water, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether. Butyl acrylate, methyl methacrylate, acrylic acid, and vinyl gallate borate were added sequentially and emulsified at 27°C and 2700 rpm for 15 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion, and 1 / 3 of the ammonium persulfate were mixed and stirred at 70°C and 400 rpm for 20 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 2 h. After the addition was complete, the temperature was raised to 85°C and stirring was continued for 1.5 h. After cooling, the pH was adjusted to 5.7 with 0.1 M hydrochloric acid to obtain an aqueous polyacrylate. (3) A water-based acrylic ester, polyurethane acrylate emulsion and photoinitiator are mixed at a mass ratio of 1:0.2:0.00015 and stirred at 27°C and 400r / min for 30min to obtain a water-based acrylic adhesive.

[0033] Comparative Example 8: A method for preparing a water-based acrylic adhesive includes the following preparation steps: (1) Weigh vinylboric acid and m-bis-gallic acid in a molar ratio of 1:1. Under a nitrogen atmosphere, mix m-bis-gallic acid and anhydrous tetrahydrofuran at a mass ratio of 1:50. Stir at 27°C and 400 r / min until completely dissolved. Add 13 wt% anhydrous tetrahydrofuran solution of vinylboric acid dropwise. After the addition is complete, add anhydrous magnesium sulfate at a mass ratio of 4.5 times that of m-bis-gallic acid. Continue stirring for 2.5 h. Filter and concentrate under reduced pressure to obtain vinyl gallate borate. Weigh the raw materials according to the following mass parts: 86 parts butyl acrylate, 20 parts methyl methacrylate, 5 parts vinyl gallate borate, 3 parts acrylic acid, 8 parts 2,2,3,3,3-pentafluoropropyl acrylate, 2.5 parts sodium dodecyl sulfate, and 1 part alkylphenol polyoxyethylene ether. 0.5 parts of ammonium persulfate, 0.7 parts of deionized water, 120 parts of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether were mixed and dissolved. Butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid and vinyl gallate borate were added sequentially. The mixture was emulsified at 27°C and 2700 r / min for 15 min to obtain a pre-emulsion. The remaining deionized water, about 1 / 5 of the pre-emulsion and 1 / 3 of the ammonium persulfate were mixed and stirred at 70°C and 400 r / min for 20 min. The remaining pre-emulsion and ammonium persulfate were added dropwise over 2 h. After the addition was complete, the temperature was raised to 85°C and stirring was continued for 1.5 h. After cooling, the pH was adjusted to 5.7 with 0.1M hydrochloric acid to obtain an aqueous polyacrylate. (2) Aqueous polyacrylate and photoinitiator were mixed at a mass ratio of 1:0.00015 and stirred at 27°C and 400r / min for 30min to obtain aqueous acrylic adhesive.

[0034] Experimental Example 1: Thermogravimetric analysis of different amounts of vinylgallic acid and boric acid added; According to the appendix Figure 1 (Thermogravimetric analysis (TGA) curves) and appendix Figure 2 As shown in the differential thermogravimetric (DTG) curves, the thermal stability of the waterborne acrylic adhesive gradually increases with the increase of vinyl gallate borate content. In the TGA curves, within the main weight loss phase, the weight loss rate tends to level off with the increase of the functional monomer content. Specifically, the TGA curves of Examples 4, 2, and 5 show... d , 5% The temperatures were 284.2°C, 286.4°C, and 288.6°C, respectively, indicating that the introduction of vinyl gallate borate enhanced the crosslinking density and char-forming ability of the system, thereby improving the overall heat resistance. Correspondingly, the DTG curves show that the temperature corresponding to the maximum weight loss rate shifts towards higher temperatures with increasing addition amount, indicating that the thermal decomposition process is slowed down and the thermal stability is enhanced.

[0035] Experimental Example 2: Determining the optimal addition amount of polyurethane acrylate emulsion; Test method: The elongation at break and tensile strength were determined according to GB528 / 92 standard. The water-based polyacrylic adhesive was poured into a dumbbell-shaped polytetrafluoroethylene mold and placed in a CL3000 UV curing apparatus (254nm, 2000mJ / cm²). 2 After curing for 2 minutes, the sample was taken out for testing at a tensile speed of 500 mm / min.

[0036] The results are shown in Table 1; By comparing Example 2 and Comparative Examples 1-4, it can be found that when the amount of polyurethane added is low, there are insufficient polyurethane segments in the system that act as multifunctional crosslinking agents. The ionic crosslinking network formed by the tertiary amine groups on the polyurethane chain and the carboxyl groups in the polyacrylate is sparse, and the amount of acrylate available for UV curing is limited, resulting in insufficient covalent crosslinking density, low overall network strength, and high elongation at break. However, when the amount of polyurethane added is too high, the dense crosslinking points and excessive rigid segments restrict the movement and extension of the polymer chain segments, resulting in excessive rigidity and increased brittleness of the material. Therefore, the elongation at break deteriorates significantly, and the breaking strength also decreases due to the uneven distribution of network stress. Therefore, a mass ratio of 0.2 between polyurethane acrylate emulsion and waterborne polyacrylate is selected.

[0037] Experimental Example 3: This example tests the performance of the water-based acrylic adhesives obtained in Examples 1-3 and Comparative Examples 5-8. The specific test items and methods are as follows: Bonding strength test method: The water-based acrylic adhesives obtained in each example and the adhesives of comparative examples 5 to 8 were cured for 2 minutes between two PC boards according to GB / T7124-2008 standard using a CL3000 UV curing machine (254nm, 2000mJ / cm2). The bonding strength was then tested using an electronic tensile testing machine at a tensile speed of 5mm / min.

[0038] Temperature and humidity resistance test method: The water-based acrylic adhesives obtained in each example and the adhesives of comparative examples 5-8 were applied between two PC boards using a CL3000 UV curing apparatus (254nm, 2000mJ / cm²). 2 After curing for 2 minutes, the cured PC-PC substrate bonding sample was placed in a high temperature and high humidity oven and left to stand for 1000 hours at 85℃ and 85% relative humidity according to GB / T5170-2016 standard. The bonding strength was then tested and compared with the bonding strength measured at room temperature.

[0039] Flame retardant performance test method: The water-based acrylic adhesives obtained in each example and the adhesives of comparative examples 5 to 8 were cured for 2 minutes using a CL3000 ultraviolet curing instrument (254nm, 2000mJ / cm2) to prepare samples of 150*60*1mm. The limiting oxygen index was tested according to GB / T2406.2-2009 standard.

[0040] The results are shown in Table 2; A comparison of the experimental data from Examples 1-3 and Comparative Examples 5-8 in Table 2 reveals that the water-based acrylic adhesive prepared by this invention has good bonding properties, water resistance, flame retardant properties, and antioxidant properties.

[0041] By comparing Examples 1-3 with Comparative Example 5, it can be found that when N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester is added during the preparation of polyurethane acrylate, its phosphonate structure can decompose to generate phosphoric acid substances when the adhesive layer is heated, which promotes the dehydration and carbonization of the polymer surface and forms a dense and insulating carbon layer to block heat and oxygen; at the same time, the tertiary amine nitrogen in its molecule can produce a synergistic effect with phosphorus, further catalyzing carbonization and expansion, and releasing inert gas to dilute combustibles, significantly improving flame retardant performance.

[0042] A comparison of Examples 1-3 with Comparative Example 6 reveals that replacing vinyl gallate borate with an equal mass of 4-vinylbenzoic acid significantly reduces the adhesive properties and thermal oxidation resistance of the waterborne acrylic adhesive. This is primarily because the replacement completely eliminates the energy dissipation network formed by the dynamic covalent bonds of the borate ester, as well as the strong free radical scavenging ability and efficient hydrogen bond network provided by the dense phenolic hydroxyl groups. In the original formulation, the dynamic borate ester bonds in the vinyl gallate borate ester molecule can undergo reversible breakage and recombination under stress, effectively dissipating energy. Furthermore, the efficient hydrogen bond network formed by multiple ortho-phenolic hydroxyl groups greatly enhances the interfacial bonding with polar substrates. Simultaneously, the multiple ortho-phenolic hydroxyl groups can efficiently capture and neutralize free radicals generated during photothermal aging, delaying polymer chain degradation.

[0043] A comparison of Examples 1-3 with Comparative Example 7 reveals that the addition of 2,2,3,3,3-pentafluoropropyl acrylate during the preparation of waterborne polyacrylate improves the moisture and water resistance of the waterborne acrylic adhesive. The CF bonds in the fluorinated acrylate monomers have extremely low surface energy, allowing them to migrate and accumulate on the coating surface during film formation and curing, forming a dense hydrophobic layer that effectively hinders the wetting, adsorption, and penetration of water molecules. Simultaneously, the high bond energy and low polarity of the CF bonds result in good chemical stability, further enhancing the overall water resistance of the adhesive layer.

[0044] By comparing Examples 1-3 with Comparative Example 8, it can be found that the absence of polyurethane acrylate emulsion in the preparation of waterborne acrylic adhesives significantly degrades their overall performance after curing. This is because the system loses the key component that builds a multi-network synergistic effect.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and not restrictive.

Claims

1. An aqueous acrylic adhesive, characterized by, The water-based acrylic adhesive is prepared by mixing a polyurethane acrylate emulsion, a water-based polyacrylate and a photoinitiator.

2. The water-based acrylic adhesive according to claim 1, characterized in that, The polyurethane acrylate emulsion is prepared by polymerization, chain extension and emulsification using polyether glycol, isophorone diisocyanate, bisphenol A glyceryl diacrylate, N,N-bis(2-hydroxyethyl) aminomethylene phosphonic acid diethyl ester, polyethylene glycol and ethylenediamine as raw materials.

3. The water-based acrylic adhesive according to claim 1, characterized in that, The water-based polyacrylate is prepared by emulsion copolymerization of butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid and vinyl gallate borate.

4. The water-based acrylic adhesive according to claim 3, characterized in that, The vinyl gallate borate is prepared by reacting vinyl boronic acid with m-digallic acid.

5. A method for preparing an aqueous acrylic adhesive, characterized by, The preparation process comprises the following steps: (1) polyether glycol, isophorone diisocyanate, bisphenol A glyceryl diacrylate, N,N-bis(2-hydroxyethyl) aminomethylene phosphonic acid diethyl ester, polyethylene glycol, ethylenediamine and anhydrous ethanol are weighed according to the molar ratio of 1:(2.95-2.98):(0.48-0.52):(0.57-0.6):(0.17-0.19):(0.57-0.6):(0.59-0.6), the polyether glycol and isophorone diisocyanate are uniformly mixed, 0.02%-0.05% stannous octoate based on the mass of the polyether glycol is added, and the mixture is reacted at 85-90°C for 1.5-2.5h, then bisphenol A glyceryl diacrylate and N,N-bis(2-hydroxyethyl) aminomethylene phosphonic acid diethyl ester are added and the reaction is continued for 1-2h, the temperature is lowered to 55-65°C, polyethylene glycol is added and the reaction is continued for 2.5-3.5h, the temperature is lowered to 25-35°C, ethylenediamine and 0.7-0.8 times the mass of the polyether glycol of acetone are added and the reaction is continued for 0.5-1.5h, 5-5.5 times the mass of the polyether glycol of deionized water is added, stirring is carried out for 0.5-1.5h, anhydrous ethanol is added and the reaction is continued for 10-20min, and a polyurethane acrylate emulsion is prepared; (2) vinyl boronic acid and m-digallic acid are weighed according to the molar ratio of 1:1, the m-digallic acid is mixed with anhydrous tetrahydrofuran according to the mass ratio of 1:(45-55), stirring is carried out at 25-30°C until the mixture is completely dissolved, 10wt%-15wt% of a solution of the vinyl boronic acid in anhydrous tetrahydrofuran is added dropwise, and 4-5 times the mass of the m-digallic acid of anhydrous magnesium sulfate is added, and a vinyl gallate borate is prepared. The raw materials are weighed according to the following mass parts: 80-90 parts of butyl acrylate, 18-22 parts of methyl methacrylate, 3-7 parts of vinyl gallate borate, 2-4 parts of acrylic acid, 7-9 parts of 2,2,3,3,3-pentafluoropropyl acrylate, 2-3 parts of sodium dodecyl sulfate, 1-2 parts of alkylphenol polyoxyethylene ether, 0.5-0.8 parts of ammonium persulfate, and 115-125 parts of deionized water. 65-75 parts of deionized water, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether are mixed and dissolved, and butyl acrylate, methyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, acrylic acid and vinyl gallate borate are added in sequence. Emulsify at 25-30°C for 10-20 min to prepare a pre-emulsion. Mix the remaining deionized water, about 1 / 5 of the pre-emulsion and 1 / 3 of the ammonium persulfate, stir at 65-75°C for 15-25 min, add the remaining pre-emulsion and ammonium persulfate dropwise within 1.5-2.5 h, heat to 80-90°C and react for 1-1.5 h, cool, adjust the pH to 5.5-6 with 0.1M hydrochloric acid to prepare an aqueous polyacrylate; (3) Mix the aqueous polyacrylate, polyurethane acrylate emulsion and photoinitiator according to the mass ratio of 1:(0.15-0.25):(0.0001-0.0002), stir at 25-30°C for 25-35 min to prepare an aqueous acrylic adhesive.

6. The method for preparing the water-based acrylic adhesive according to claim 5, characterized in that, In step (1), the polyether glycol type is N210; the polyethylene glycol is polyethylene glycol 2000.

7. The method for preparing the water-based acrylic adhesive according to claim 5, characterized in that, In step (1), the polyurethane acrylate emulsion reaction process is as follows: 。 8. The method for preparing the water-based acrylic adhesive according to claim 5, characterized in that, In step (2), the aqueous polyacrylate reaction process is as follows: 。 9. The method for preparing the water-based acrylic adhesive according to claim 5, characterized in that, In step (3), the photoinitiator is photoinitiator 2959.

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