Acrylic resin emulsion and preparation method thereof

Abstract

The invention provides an acrylic resin emulsion and a preparation method thereof, and the preparation method comprises the following steps: (1) in a nitrogen atmosphere, mixing 1-2 parts by weight of trimellitic anhydride, 2-3 parts by weight of hydroxyethyl acrylate, 0.1-0.3 part by weight of isopropyl titanate and 40-45 parts by weight of N, N-dimethylformamide, and reacting to obtain a modified intermediate; (2) mixing the modified intermediate, 60-70 parts of a mixed monomer, 1.2-1.6 parts of mercaptoethanol and 1-2 parts of azodiisobutyronitrile, heating to 140-145 DEG C, and reacting for 5-6 hours to obtain a reaction product; and (3) mixing the reaction product, a surfactant and the modified diatomite, stirring at 55-60 DEG C for 1-2 hours, then adding deionized water, and continuously stirring for 3-4 hours to obtain the acrylic resin emulsion. The acrylic resin emulsion is low in viscosity, high in solid content and good in stability.

Description

Technical Field

[0001] The invention belongs to the technical field of acrylic resins, and in particular relates to an acrylic resin emulsion and a preparation method thereof. Background Art

[0002] Acrylic resin emulsion is a polymer compound dispersion prepared by emulsion polymerization technology in an aqueous medium with acrylic ester monomers (such as methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate, etc.) as the main raw materials. It is a stable aqueous dispersion containing polymer particles, water, emulsifiers, initiators, additives and other components, in which the diameter of the polymer particles is usually between a few nanometers and hundreds of nanometers. The characteristics of acrylic resin emulsion include: Environmental protection and low VOC: Since water is used as the dispersion medium, its volatile organic compound (VOC) content is low compared to solvent-based resins, which is more environmentally friendly. Good physical properties: It has excellent gloss, flexibility, adhesion and weather resistance, and is suitable for a variety of substrates such as metal, plastic, wood, paper and concrete. Wide applicability: It is widely used in architectural coatings, latex paints, waterproof materials, textile coatings, leather processing, adhesives, printing inks and other fields. Processing convenience: It can be directly diluted with water, which is convenient for construction and cleaning, and reduces the risk of fire. Low-temperature polymerization: Emulsion polymerization can be carried out at a relatively low temperature, saving energy and conducive to production safety.

[0003] Traditional hydroxy acrylic resin is a linear polymer obtained by free radical polymerization of functionalized vinyl monomers. At high concentrations, molecules are easily entangled with each other and have great resistance to movement. It is difficult to obtain a low-viscosity emulsion while ensuring a high solid content. Developing an acrylic resin emulsion with low viscosity, high solid content and simple preparation method is an urgent problem that needs to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide an acrylic resin emulsion and a preparation method thereof.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a method for preparing an acrylic resin emulsion, comprising the following steps: in parts by weight, (1) Under a nitrogen atmosphere, 1-2 parts of trimellitic anhydride, 2-3 parts of hydroxyethyl acrylate, 0.1-0.3 parts of isopropyl titanate and 40-45 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80-85°C, and the temperature was kept for 1-2 hours, and the temperature was raised to 110-120°C, and the temperature was kept for 3-4 hours to obtain a modified intermediate; (2) Mix the modified intermediate, 60-70 parts of the mixed monomer, 1.2-1.6 parts of mercaptoethanol and 1-2 parts of azobisisobutyronitrile, raise the temperature to 140-145° C., react for 5-6 hours, and obtain a reaction product; (3) Mix the reaction product, surfactant and modified diatomaceous earth in a mass ratio of 1:0.04-0.07:0.1-0.12, stir at 55-60°C for 1-2 hours, then add deionized water and continue stirring for 3-4 hours to obtain an acrylic resin emulsion.

[0006] Furthermore, the mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.3-1.7:0.5-0.8.

[0007] Furthermore, the surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.3-1.5:0.6-0.9, and the preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5-0.7:2.2-2.5, heat to 56-58°C, stir evenly, and keep warm for 6-8 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126-128°C and react for 6-8 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115-120°C for 5-7h; cool to 65-70°C, add sodium chloroacetate, and keep warm for 9-10h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0008] Furthermore, the molar number of dodecylphenol polyoxyethylene ether is 2 to 3 times that of hexadecylphenol polyoxyethylene ether.

[0009] Furthermore, the molar number of p-toluenesulfonic acid is 0.03 to 0.05 times that of hexadecylphenol polyoxyethylene ether.

[0010] Furthermore, the molar number of sodium hydroxide is 0.04 to 0.06 times that of hexadecylphenol polyoxyethylene ether.

[0011] Furthermore, the molar number of toluene is 6 to 8 times that of hexadecylphenol polyoxyethylene ether.

[0012] Furthermore, the molar number of sodium chloroacetate is 4 to 5 times that of hexadecylphenol polyoxyethylene ether.

[0013] Furthermore, the preparation method of the modified diatomaceous earth is: dispersing 100 parts by weight of diatomaceous earth in 240-250 parts by weight of water, adding 6-7 parts by weight of acrylamide, 2-3 parts by weight of 2-dodecyl methacrylate and 0.2-0.4 parts by weight of ammonium persulfate, stirring and reacting at 65-67° C. for 4-5 hours, filtering, drying and crushing to obtain the modified diatomaceous earth.

[0014] The invention provides acrylic resin emulsion prepared by the preparation method.

[0015] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: the present invention selects a specific mixed monomer to react with a variety of raw materials, and the obtained acrylic resin has a more branched structure, thereby reducing the viscosity of the acrylic resin emulsion and increasing its solid content; at the same time, the viscosity of the acrylic resin emulsion at 25°C is lower than that of most acrylic resin emulsions on the market, has good dilution and leveling properties, and is easier to process and shape. The present invention can improve the viscosity of the emulsion by adding modified diatomaceous earth, and use a special surfactant to improve the stability of the emulsion. DETAILED DESCRIPTION

[0016] 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.

[0017] Example 1 This embodiment provides a method for preparing an acrylic resin emulsion, comprising the following steps: in parts by weight, (1) Under a nitrogen atmosphere, 1 part of trimellitic anhydride, 2 parts of hydroxyethyl acrylate, 0.1 parts of isopropyl titanate and 40 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80°C, the temperature was kept for 1 hour, the temperature was raised to 110°C, the temperature was kept for 3 hours, and a modified intermediate was obtained; (2) The modified intermediate, 60 parts of the mixed monomer, 1.2 parts of mercaptoethanol and 1 part of azobisisobutyronitrile were mixed, the temperature was raised to 140° C., and the reaction was carried out for 5 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth were mixed in a mass ratio of 1:0.04:0.1, stirred at 55° C. for 1 h, and then deionized water was added and stirred for 3 h to obtain an acrylic resin emulsion.

[0018] The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.3:0.5.

[0019] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.3:0.6. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5:2.2, heat to 56°C, stir evenly, and keep warm for 6 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126°C and react for 6 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115°C for 5 h; cool to 65°C, add sodium chloroacetate, and keep warm for 9 h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0020] The molar number of dodecylphenol polyoxyethylene ether is twice that of hexadecylphenol polyoxyethylene ether.

[0021] The molar number of p-toluenesulfonic acid is 0.03 times that of hexadecylphenol polyoxyethylene ether.

[0022] The molar number of sodium hydroxide is 0.04 times that of hexadecylphenol polyoxyethylene ether.

[0023] The molar number of toluene is 6 times that of hexadecylphenol polyoxyethylene ether.

[0024] The molar number of sodium chloroacetate is 4 times that of hexadecylphenol polyoxyethylene ether.

[0025] The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 240 parts by weight of water, 6 parts by weight of acrylamide, 2 parts by weight of 2-dodecyl methacrylate and 0.2 parts by weight of ammonium persulfate are added, and the mixture is stirred at 65° C. for 4 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

[0026] Example 2 This embodiment provides a method for preparing an acrylic resin emulsion, comprising the following steps: in parts by weight, (1) Under a nitrogen atmosphere, 2 parts of trimellitic anhydride, 3 parts of hydroxyethyl acrylate, 0.3 parts of isopropyl titanate and 45 parts of N,N-dimethylformamide were mixed, the temperature was raised to 85°C, the temperature was kept for 2 hours, the temperature was raised to 120°C, the temperature was kept for 4 hours, and a modified intermediate was obtained; (2) The modified intermediate, 70 parts of the mixed monomer, 1.6 parts of mercaptoethanol and 2 parts of azobisisobutyronitrile were mixed, the temperature was raised to 145° C., and the reaction was carried out for 6 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth in a mass ratio of 1:0.07:0.12 were mixed, stirred at 60° C. for 2 h, and then deionized water was added and stirred for 4 h to obtain an acrylic resin emulsion.

[0027] The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.7:0.8.

[0028] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.5:0.9. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.7:2.5, heat to 58°C, stir evenly, and keep warm for 8 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 128°C and react for 8 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 120°C for 7 h; cool to 70°C, add sodium chloroacetate, and keep warm for 10 h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0029] The molar number of dodecylphenol polyoxyethylene ether is 3 times that of hexadecylphenol polyoxyethylene ether.

[0030] The molar number of p-toluenesulfonic acid is 0.05 times that of hexadecylphenol polyoxyethylene ether.

[0031] The molar number of sodium hydroxide is 0.06 times that of hexadecylphenol polyoxyethylene ether.

[0032] The molar number of toluene is 8 times that of hexadecylphenol polyoxyethylene ether.

[0033] The molar number of sodium chloroacetate is 5 times that of hexadecylphenol polyoxyethylene ether.

[0034] The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 250 parts by weight of water, 7 parts by weight of acrylamide, 3 parts by weight of 2-dodecyl methacrylate and 0.4 parts by weight of ammonium persulfate are added, and the mixture is stirred and reacted at 67° C. for 5 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that the mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1:1.

[0036] A method for preparing an acrylic resin emulsion comprises the following steps: in parts by weight: (1) Under a nitrogen atmosphere, 1 part of trimellitic anhydride, 2 parts of hydroxyethyl acrylate, 0.1 parts of isopropyl titanate and 40 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80°C, the temperature was kept for 1 hour, the temperature was raised to 110°C, the temperature was kept for 3 hours, and a modified intermediate was obtained; (2) The modified intermediate, 60 parts of the mixed monomer, 1.2 parts of mercaptoethanol and 1 part of azobisisobutyronitrile were mixed, the temperature was raised to 140° C., and the reaction was carried out for 5 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth were mixed in a mass ratio of 1:0.04:0.1, stirred at 55° C. for 1 h, and then deionized water was added and stirred for 3 h to obtain an acrylic resin emulsion.

[0037] The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1:1.

[0038] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.3:0.6. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5:2.2, heat to 56°C, stir evenly, and keep warm for 6 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126°C and react for 6 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115°C for 5 h; cool to 65°C, add sodium chloroacetate, and keep warm for 9 h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0039] The molar number of dodecylphenol polyoxyethylene ether is twice that of hexadecylphenol polyoxyethylene ether.

[0040] The molar number of p-toluenesulfonic acid is 0.03 times that of hexadecylphenol polyoxyethylene ether.

[0041] The molar number of sodium hydroxide is 0.04 times that of hexadecylphenol polyoxyethylene ether.

[0042] The molar number of toluene is 6 times that of hexadecylphenol polyoxyethylene ether.

[0043] The molar number of sodium chloroacetate is 4 times that of hexadecylphenol polyoxyethylene ether.

[0044] The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 240 parts by weight of water, 6 parts by weight of acrylamide, 2 parts by weight of 2-dodecyl methacrylate and 0.2 parts by weight of ammonium persulfate are added, and the mixture is stirred at 65° C. for 4 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

[0045] Comparative Example 2 The difference between this comparative example and Example 1 is that the mixed monomer is replaced by styrene.

[0046] A method for preparing an acrylic resin emulsion comprises the following steps: in parts by weight: (1) Under a nitrogen atmosphere, 1 part of trimellitic anhydride, 2 parts of hydroxyethyl acrylate, 0.1 parts of isopropyl titanate and 40 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80°C, the temperature was kept for 1 hour, the temperature was raised to 110°C, the temperature was kept for 3 hours, and a modified intermediate was obtained; (2) Mix the modified intermediate, 60 parts of styrene, 1.2 parts of mercaptoethanol and 1 part of azobisisobutyronitrile, heat to 140°C, and react for 5 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth were mixed in a mass ratio of 1:0.04:0.1, stirred at 55° C. for 1 h, and then deionized water was added and stirred for 3 h to obtain an acrylic resin emulsion.

[0047] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.3:0.6. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5:2.2, heat to 56°C, stir evenly, and keep warm for 6 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126°C and react for 6 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115°C for 5 h; cool to 65°C, add sodium chloroacetate, and keep warm for 9 h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0048] The molar number of dodecylphenol polyoxyethylene ether is twice that of hexadecylphenol polyoxyethylene ether.

[0049] The molar number of p-toluenesulfonic acid is 0.03 times that of hexadecylphenol polyoxyethylene ether.

[0050] The molar number of sodium hydroxide is 0.04 times that of hexadecylphenol polyoxyethylene ether.

[0051] The molar number of toluene is 6 times that of hexadecylphenol polyoxyethylene ether.

[0052] The molar number of sodium chloroacetate is 4 times that of hexadecylphenol polyoxyethylene ether.

[0053] The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 240 parts by weight of water, 6 parts by weight of acrylamide, 2 parts by weight of 2-dodecyl methacrylate and 0.2 parts by weight of ammonium persulfate are added, and the mixture is stirred at 65° C. for 4 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

[0054] Comparative Example 3 The difference between this comparative example and Example 1 is that the nonionic surfactant is replaced by hydroxyethyl cetyl dimethyl ammonium phosphate.

[0055] A method for preparing an acrylic resin emulsion comprises the following steps: in parts by weight: (1) Under a nitrogen atmosphere, 1 part of trimellitic anhydride, 2 parts of hydroxyethyl acrylate, 0.1 parts of isopropyl titanate and 40 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80°C, the temperature was kept for 1 hour, the temperature was raised to 110°C, the temperature was kept for 3 hours, and a modified intermediate was obtained; (2) The modified intermediate, 60 parts of the mixed monomer, 1.2 parts of mercaptoethanol and 1 part of azobisisobutyronitrile were mixed, the temperature was raised to 140° C., and the reaction was carried out for 5 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth were mixed in a mass ratio of 1:0.04:0.1, stirred at 55° C. for 1 h, and then deionized water was added and stirred for 3 h to obtain an acrylic resin emulsion.

[0056] The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.3:0.5.

[0057] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and hydroxyethyl cetyl dimethyl ammonium phosphate in a mass ratio of 1:1.3:0.6.

[0058] The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 240 parts by weight of water, 6 parts by weight of acrylamide, 2 parts by weight of 2-dodecyl methacrylate and 0.2 parts by weight of ammonium persulfate are added, and the mixture is stirred at 65° C. for 4 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

[0059] Comparative Example 4 The difference between this comparative example and Example 1 is that the surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1:1.

[0060] A method for preparing an acrylic resin emulsion comprises the following steps: in parts by weight: (1) Under a nitrogen atmosphere, 1 part of trimellitic anhydride, 2 parts of hydroxyethyl acrylate, 0.1 parts of isopropyl titanate and 40 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80°C, the temperature was kept for 1 hour, the temperature was raised to 110°C, the temperature was kept for 3 hours, and a modified intermediate was obtained; (2) The modified intermediate, 60 parts of the mixed monomer, 1.2 parts of mercaptoethanol and 1 part of azobisisobutyronitrile were mixed, the temperature was raised to 140° C., and the reaction was carried out for 5 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth were mixed in a mass ratio of 1:0.04:0.1, stirred at 55° C. for 1 h, and then deionized water was added and stirred for 3 h to obtain an acrylic resin emulsion.

[0061] The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.3:0.5.

[0062] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1:1. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5:2.2, heat to 56°C, stir evenly, and keep warm for 6 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126°C and react for 6 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115°C for 5 h; cool to 65°C, add sodium chloroacetate, and keep warm for 9 h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0063] The molar number of dodecylphenol polyoxyethylene ether is twice that of hexadecylphenol polyoxyethylene ether.

[0064] The molar number of p-toluenesulfonic acid is 0.03 times that of hexadecylphenol polyoxyethylene ether.

[0065] The molar number of sodium hydroxide is 0.04 times that of hexadecylphenol polyoxyethylene ether.

[0066] The molar number of toluene is 6 times that of hexadecylphenol polyoxyethylene ether.

[0067] The molar number of sodium chloroacetate is 4 times that of hexadecylphenol polyoxyethylene ether.

[0068] The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 240 parts by weight of water, 6 parts by weight of acrylamide, 2 parts by weight of 2-dodecyl methacrylate and 0.2 parts by weight of ammonium persulfate are added, and the mixture is stirred at 65° C. for 4 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

[0069] Comparative Example 5 The difference between this comparative example and Example 1 is that the preparation method of the modified diatomaceous earth is different.

[0070] A method for preparing an acrylic resin emulsion comprises the following steps: in parts by weight: (1) Under a nitrogen atmosphere, 1 part of trimellitic anhydride, 2 parts of hydroxyethyl acrylate, 0.1 parts of isopropyl titanate and 40 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80°C, the temperature was kept for 1 hour, the temperature was raised to 110°C, the temperature was kept for 3 hours, and a modified intermediate was obtained; (2) The modified intermediate, 60 parts of the mixed monomer, 1.2 parts of mercaptoethanol and 1 part of azobisisobutyronitrile were mixed, the temperature was raised to 140° C., and the reaction was carried out for 5 hours to obtain a reaction product; (3) The reaction product, surfactant and modified diatomaceous earth were mixed in a mass ratio of 1:0.04:0.1, stirred at 55° C. for 1 h, and then deionized water was added and stirred for 3 h to obtain an acrylic resin emulsion.

[0071] The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.3:0.5.

[0072] The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.3:0.6. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5:2.2, heat to 56°C, stir evenly, and keep warm for 6 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126°C and react for 6 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115°C for 5 h; cool to 65°C, add sodium chloroacetate, and keep warm for 9 h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

[0073] The molar number of dodecylphenol polyoxyethylene ether is twice that of hexadecylphenol polyoxyethylene ether.

[0074] The molar number of p-toluenesulfonic acid is 0.03 times that of hexadecylphenol polyoxyethylene ether.

[0075] The molar number of sodium hydroxide is 0.04 times that of hexadecylphenol polyoxyethylene ether.

[0076] The molar number of toluene is 6 times that of hexadecylphenol polyoxyethylene ether.

[0077] The molar number of sodium chloroacetate is 4 times that of hexadecylphenol polyoxyethylene ether.

[0078] The preparation method of the modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth, 2 parts by weight of KH550 and 500 parts by weight of acetone are mixed, stirred at 40° C. for 3 hours, filtered, dried and crushed to obtain the modified diatomaceous earth.

[0079] Performance Testing The products of Examples 1-2 and Comparative Examples 1-5 were subjected to performance tests.

[0080] 1. Viscosity: Brookfield vertebral plate viscometer DV-II+CP is used to detect the viscosity of the sample.

[0081] 2. Solid content: Tested in accordance with GB / T6751-1986 "Determination of volatile and non-volatile matter in paints and varnishes".

[0082] 3. Pencil hardness: The acrylic resin emulsion and the Bayer HL-BA curing agent were uniformly mixed in a mass ratio of 5:1 to obtain a coating solution; the coating solution was coated on a transparent PET film substrate using a No. 25 (the wet film thickness can be 20 μm, and the dry film thickness = wet film thickness × solid content) coating rod, and the coating was placed in an oven at 80° C. and baked for 2 min, and then taken out to obtain a coating, and the pencil hardness of the coating was tested using an automatic pencil hardness tester.

[0083] 4. Stability: Store the acrylic resin emulsion at 40°C for 180 days and observe whether there is stratification or precipitation.

[0084] The test results are shown in Table 1: Table 1 Performance test results

[0085] According to the data in Table 1, it can be seen that the acrylic resin emulsion provided by the present invention has increased pencil hardness, higher solid content and lower viscosity, meets current environmental protection requirements, and has high application value. Comparative Examples 1-5 show that changing the preparation raw materials and conditions will reduce the overall performance.

[0086] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an acrylic resin emulsion, characterized in that: The following steps are involved: According to weight parts, (1) Under a nitrogen atmosphere, 1-2 parts of trimellitic anhydride, 2-3 parts of hydroxyethyl acrylate, 0.1-0.3 parts of isopropyl titanate and 40-45 parts of N,N-dimethylformamide were mixed, the temperature was raised to 80-85°C, and the temperature was kept for 1-2 hours, and the temperature was raised to 110-120°C, and the temperature was kept for 3-4 hours to obtain a modified intermediate; (2) Mix the modified intermediate, 60-70 parts of the mixed monomer, 1.2-1.6 parts of mercaptoethanol and 1-2 parts of azobisisobutyronitrile, raise the temperature to 140-145° C., react for 5-6 hours, and obtain a reaction product; (3) Mix the reaction product, surfactant and modified diatomaceous earth in a mass ratio of 1:0.04-0.07:0.1-0.12, stir at 55-60°C for 1-2 hours, then add deionized water and continue stirring for 3-4 hours to obtain an acrylic resin emulsion.

2. The method for preparing an acrylic resin emulsion according to claim 1, wherein The mixed monomer is a mixture of styrene, alkyl acrylate and tert-butyl glycidyl carbonate in a mass ratio of 1:1.3-1.7:0.5-0.

8.

3. The method for preparing an acrylic resin emulsion according to claim 1, wherein The surfactant is a mixture of disodium octadecyl succinamide sulfonate, cocamidopropyl betaine and a nonionic surfactant in a mass ratio of 1:1.3-1.5:0.6-0.

9. The preparation method of the nonionic surfactant is as follows: (1) Mix hexadecylphenol polyoxyethylene ether, sodium hydroxide and formaldehyde in a molar ratio of 1:0.5-0.7:2.2-2.5, heat to 56-58°C, stir evenly, and keep warm for 6-8 hours to obtain product A; (2) Add dodecylphenol polyoxyethylene ether to product A, adjust the pH to 7 with hydrochloric acid, add p-toluenesulfonic acid, remove moisture by vacuum, raise the temperature to 126-128°C and react for 6-8 hours to obtain product B; (3) Add sodium hydroxide and toluene to product B, mix well, and keep warm at 115-120°C for 5-7h; cool to 65-70°C, add sodium chloroacetate, and keep warm for 9-10h; add hydrochloric acid to adjust the pH to neutral, remove toluene and water under reduced pressure, add ethanol and filter, and remove ethanol by rotary evaporation under reduced pressure to obtain a nonionic surfactant.

4. The method for preparing an acrylic resin emulsion according to claim 3, wherein The molar number of dodecylphenol polyoxyethylene ether is 2 to 3 times that of hexadecylphenol polyoxyethylene ether.

5. The method for preparing the acrylic resin emulsion according to claim 3, characterized in that: The molar number of p-toluenesulfonic acid is 0.03 to 0.05 times that of hexadecylphenol polyoxyethylene ether.

6. The method for preparing the acrylic resin emulsion according to claim 3, characterized in that: The molar number of sodium hydroxide is 0.04 to 0.06 times that of hexadecylphenol polyoxyethylene ether.

7. The method for preparing the acrylic resin emulsion according to claim 3, characterized in that: The molar number of toluene is 6 to 8 times that of hexadecylphenol polyoxyethylene ether.

8. The method for preparing the acrylic resin emulsion according to claim 3, characterized in that: The molar number of sodium chloroacetate is 4 to 5 times that of hexadecylphenol polyoxyethylene ether.

9. The method for preparing an acrylic resin emulsion according to claim 1, characterized in that: The preparation method of modified diatomaceous earth is as follows: 100 parts by weight of diatomaceous earth is dispersed in 240-250 parts by weight of water, 6-7 parts by weight of acrylamide, 2-3 parts by weight of 2-dodecyl methacrylate and 0.2-0.4 parts by weight of ammonium persulfate are added, and the mixture is stirred at 65-67° C. for 4-5 hours, and the modified diatomaceous earth is obtained by filtering, drying and crushing.

10. An acrylic resin emulsion prepared according to the preparation method according to any one of claims 1 to 9.

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