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CN-121975406-A - Low-water-absorption weather-resistant coating and preparation method thereof

CN121975406ACN 121975406 ACN121975406 ACN 121975406ACN-121975406-A

Abstract

The invention relates to the technical field of paint and discloses a low-water-absorption weather-resistant paint and a preparation method thereof, wherein the low-water-absorption weather-resistant paint comprises 67-74 parts of epoxy acrylate, 26-33 parts of active diluent, 3-3.6 parts of photoinitiator, 2-8 parts of silane modified lignin and the like, the modified lignin contains alkenyl, and the modified lignin and the epoxy acrylate undergo a photo-curing reaction to enable the lignin to be chemically crosslinked into a paint film matrix, so that the binding force between the lignin and the paint film is enhanced, and the paint film has higher hardness, impact resistance and the like. After the modified lignin photocrosslinks the epoxy acrylate, the crosslinking degree of a paint film molecular chain becomes large, so that corrosive medium can be prevented from penetrating into the paint film, and the salt spray resistance of the paint film can be improved. And the hydrophilic hydroxyl of the modified lignin is reduced, and meanwhile, a hydrophobic silane structure is introduced, so that the water absorption rate of a paint film is reduced, and the water resistance of the paint film is improved.

Inventors

  • LI GUANGKUO
  • ZHAO CHUNXU
  • SONG XIAODONG

Assignees

  • 广州和新实业有限公司

Dates

Publication Date
20260505
Application Date
20260319

Claims (8)

  1. 1. The low-water-absorption weather-resistant coating is characterized by comprising, by mass, 67-74 parts of epoxy acrylate, 26-33 parts of reactive diluent, 3-3.6 parts of photoinitiator, 2-8 parts of silane modified lignin, 10-20 parts of filler and 0.2-0.5 part of dispersing agent.
  2. 2. The low water absorption weatherable coating according to claim 1, wherein the reactive diluent is one or a combination of tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1, 6-hexanediol diacrylate, trimethylolpropane trimethacrylate.
  3. 3. The low water absorption weatherable coating according to claim 1, wherein the photoinitiator is one or a combination of photoinitiator 1173, photoinitiator 184, and photoinitiator TPO.
  4. 4. The low water absorption weatherable coating according to claim 1, wherein the filler is one or a combination of titanium dioxide, silica, and calcium carbonate.
  5. 5. A method of preparing a low water absorption weatherable coating according to any one of claims 1 to 4, comprising: (1) Adding lignin into N, N-dimethylformamide, stirring, adding 3- (chlorodimethylsilyl) propyl methacrylate and imidazole, stirring for reaction, pouring the solution into water, filtering, washing the product, and drying to obtain silane modified lignin; (2) Adding epoxy acrylate, silane modified lignin, filler and dispersing agent into the reactive diluent, dispersing in a high-speed shearing machine, adding photoinitiator, and stirring and uniformly mixing to obtain the weather-resistant coating with low water absorption rate.
  6. 6. The method for producing a low water absorption weather resistant coating according to claim 5, wherein the reaction temperature in (1) is 15 to 30 ℃ and the reaction time is 7 to 12 hours.
  7. 7. The method for producing a low water absorption weather resistant coating according to claim 5, wherein the lignin in (1) is 100 parts by mass, the 3- (chlorodimethylsilyl) propyl methacrylate is 20-60 parts by mass, and the imidazole is 6.2-18.6 parts by mass.
  8. 8. The method for preparing a low water absorption weather resistant paint according to claim 7, wherein the method for preparing 3- (chlorodimethylsilyl) propyl methacrylate is characterized in that 100 parts by weight of allyl methacrylate and 0.7-0.8 part by weight of a Kadset catalyst are added into toluene, the mixture is heated to 70-75 ℃, toluene solution containing 84-90 parts of dimethylchlorosilane is added dropwise, the mixture is stirred and reacted for 3-4 hours, and the solution is distilled under reduced pressure to obtain 3- (chlorodimethylsilyl) propyl methacrylate.

Description

Low-water-absorption weather-resistant coating and preparation method thereof Technical Field The invention relates to the technical field of coatings, in particular to a low-water-absorption weather-resistant coating and a preparation method thereof. Background The coating is mainly used for corrosion protection of products such as metal, woodware and the like, and the curing method of the coating mainly comprises room temperature curing, heat curing, chemical crosslinking curing, photo curing and the like. The photo-curing coating, such as epoxy acrylate, does not contain an organic solvent, is environment-friendly, has high curing speed and convenient construction, is excellent in film forming, and is wide in applicable base material and very wide in application. However, the epoxy acrylate photo-curing coating film has the defects of high moisture absorption rate, poor water resistance, low mechanical properties such as impact resistance and the like, and easiness in occurrence of phenomena such as breakage and cracking. Lignin is a renewable resource, is cheap and easy to obtain, is environment-friendly, contains a large number of aromatic ring structures, has good mechanical properties, heat resistance and other properties, and has important application in materials such as paint, printing ink and the like. Patent CN111923540B discloses a wear-resistant and yellowing-resistant decorative material and a preparation method thereof, and modified nano titanium dioxide coated with quaternary ammonium salt chitosan and sulfonated lignin on the surface can improve the wear resistance, yellowing resistance and other properties of the coating such as epoxy acrylate and the like, but the patent does not solve the problem of water resistance of the coating. Poor salt fog resistance and other performances. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the weather-resistant paint with low water absorption rate and the preparation method thereof, and solves the problems of poor performances such as water resistance, heat resistance, weather resistance and the like of the epoxy acrylate paint. The technical scheme adopted by the invention is that the weather-resistant paint with low water absorption comprises, by mass, 67-74 parts of epoxy acrylate, 26-33 parts of reactive diluent, 3-3.6 parts of photoinitiator, 2-8 parts of silane modified lignin, 10-20 parts of filler and 0.2-0.5 part of dispersing agent. Further, the reactive diluent is one or a combination of tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1, 6-hexanediol diacrylate and trimethylolpropane trimethacrylate. Further, the photoinitiator is one or a combination of a photoinitiator 1173, a photoinitiator 184 and a photoinitiator TPO. Further, the filler is one or a combination of titanium dioxide, silicon dioxide and calcium carbonate. Further, the preparation method of the weather-resistant paint with low water absorption rate comprises the following steps: (1) Allyl methacrylate and a Kadset catalyst are added into toluene, the mixture is heated to the reaction temperature, a toluene solution containing dimethylchlorosilane is dripped into the mixture, the mixture is stirred and reacted, and low-boiling substances are removed by reduced pressure distillation of the solution, so that 3- (chlorodimethylsilyl) propyl methacrylate is obtained. The preparation reaction formula is as follows: 。 (2) Adding lignin into N, N-dimethylformamide, stirring, adding 3- (chlorodimethylsilyl) propyl methacrylate and imidazole, stirring for reaction, pouring the solution into water, filtering, washing the product with water and ethanol, and drying to obtain silane modified lignin. (2) Adding epoxy acrylate, silane modified lignin, filler and dispersing agent into the reactive diluent, dispersing in a high-speed shearing machine, adding photoinitiator, and stirring and uniformly mixing to obtain the weather-resistant coating with low water absorption rate. Further, in the (1), 100 parts by mass of allyl methacrylate, 0.7 to 0.8 part by mass of a Karster catalyst and 84 to 90 parts by mass of dimethylchlorosilane are used. Further, the reaction temperature in (1) is 70-75 ℃ and the reaction time is 3-4h. Further, the temperature of the reaction in (2) is 15-30 ℃ and the reaction time is 7-12h. Further, in the step (2), 100 parts by mass of lignin, 20-60 parts by mass of 3- (chlorodimethylsilyl) propyl methacrylate and 6.2-18.6 parts by mass of imidazole are calculated. The invention has the beneficial technical effects that the active Si-Cl of the 3- (chlorodimethylsilyl) propyl methacrylate is utilized to react with the hydroxyl of lignin to obtain silane modified lignin, and then the silane modified lignin is mixed with film forming substances such as epoxy acrylate, active diluent, photoinitiator, filler and the like to obtain the weather-resistant paint with low water absorption rate. The modified lignin conta