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CN-122011895-A - Nano anti-corrosion coating for chassis, preparation method and spraying method thereof

CN122011895ACN 122011895 ACN122011895 ACN 122011895ACN-122011895-A

Abstract

The invention relates to the technical field of automobile spraying, in particular to a nano anti-corrosion coating for a chassis, a preparation method thereof and a spraying method thereof. The raw material components of the nano anti-corrosion coating comprise, by mass, 50-60% of aqueous epoxy resin, 1.0-1.5% of modified nano particles, 0.8-1.2% of pH response type corrosion inhibitor microcapsules, 0.5-1.0% of dispersing agent, 0.3-0.6% of wetting agent, 0.2-0.4% of defoaming agent, 0.1-0.3% of leveling agent and the balance of deionized water. The composite spraying technology of the invention improves the dispersion uniformity of nano particles by more than 40%, the thickness deviation of the coating is controlled within +/-3 mu m, the optimized curing technology improves the construction efficiency by 35%, and the energy consumption is reduced to 3.2 kW.h/m < 2 >.

Inventors

  • WANG JING
  • Yu Shangheng

Assignees

  • 奇瑞汽车股份有限公司

Dates

Publication Date
20260512
Application Date
20260108

Claims (10)

  1. 1. A nano anticorrosive paint for chassis is characterized in that the raw material components of the nano anticorrosive paint comprise, by mass percent, 50-60Wt% of aqueous epoxy resin, 1.0-1.5wt% of modified nano particles, 0.8-1.2wt% of pH response type corrosion inhibitor microcapsules, 0.5-1.0wt% of dispersing agent, 0.3-0.6wt% of wetting agent, 0.2-0.4wt% of defoaming agent, 0.1-0.3wt% of leveling agent and the balance of deionized water.
  2. 2. The nano anticorrosive paint for chassis according to claim 1, wherein, The aqueous epoxy resin comprises one or more of E-44 type aqueous epoxy resin, E-20 type aqueous epoxy resin and E-51 type aqueous epoxy resin, and/or, The dispersant comprises a polycarboxylate type dispersant, and/or, The wetting agent comprises one or more of organosiloxane, alkyl sulfate or polyoxyethylene fatty alcohol ether, and/or, The defoamer comprises one or more of mineral oil, organic silicon or polyether, and/or, The leveling agent comprises one or more of fluorocarbon modified acrylic ester, polydimethylsiloxane or polyurethane prepolymer.
  3. 3. The nano anti-corrosion coating for chassis according to claim 1, wherein the modified nano-particles are silane coupling agent modified SiO 2 /ZnO composite nano-particles, The silane coupling agent comprises one or more of KH550 silane coupling agent, KH792 silane coupling agent or KH602 silane coupling agent, and/or, The mass ratio of SiO 2 to ZnO in the SiO 2 /ZnO composite nano-particle is 100 (1-1.3), and/or, The particle size of the SiO 2 /ZnO composite nano-particles modified by the silane coupling agent is 30-50nm.
  4. 4. The nano anticorrosive paint for chassis according to claim 1, wherein, The pH response type corrosion inhibitor microcapsule comprises a core material and a wall material, wherein, The core material comprises one or more of benzotriazole derivatives, 2-mercaptobenzothiazole or mercaptobenzimidazole, and/or, The wall material comprises one or more of polyurethane, polylactic acid, polycaprolactone, polyacrylic acid or polyethyleneimine.
  5. 5. A method of preparing a nano-grade anti-corrosive paint for a chassis according to any one of claims 1 to 4, comprising: uniformly mixing the modified nano particles with a dispersing agent to obtain pre-dispersed slurry; Heating the water-based epoxy resin to a first temperature, adding the water-based epoxy resin into the pre-dispersed slurry preheated to the first temperature, and stirring the slurry for a first preset time at a first stirring speed to obtain a first slurry; sequentially adding a wetting agent, a defoaming agent and a leveling agent into the first slurry, and keeping the first temperature for continuously stirring for a second preset time to obtain a second slurry; and adding the corrosion inhibitor microcapsule into the second slurry, and stirring for a third preset time at a second stirring speed under a vacuum condition to obtain the nano anti-corrosion coating for the chassis.
  6. 6. The method for preparing the nano anti-corrosion coating for the chassis according to claim 5, wherein, The first temperature is 39-42 ℃, the first stirring speed is 500-600 rpm, 20-30 min after the first preset time, and/or, The second preset time is 15-20 min, and/or, The second stirring speed is 200-300 rpm, and the third preset time is 8-10 min.
  7. 7. A method of spraying a nano-grade anti-corrosion coating for a chassis according to any one of claims 1 to 4, wherein the spraying method comprises: Carrying out plasma pretreatment on the surface of the substrate; Adopting a composite spraying system to spray the nano anti-corrosion paint for the chassis on the surface of the pretreated base material according to a preset track path in multiple passes; and carrying out infrared gradient curing on the sprayed base material to form a coating.
  8. 8. The method for spraying nano anticorrosive paint for chassis according to claim 7, wherein, The ion pretreatment is carried out in an inert atmosphere with the power of 600-1000W, the treatment distance of 50-120 mm and the treatment time of 30-90 s.
  9. 9. The method of spraying a nano anti-corrosive paint for a chassis according to claim 7, wherein the spraying conditions of the composite spraying system include: High-pressure airless spraying pressure of 8-10MPa, electrostatic auxiliary voltage of 60-80kV, nozzle cone angle of 40-60 degrees, aperture of 0.25-0.35 mm, spray distance of 250-300mm, and/or, The multi-pass spraying process comprises the steps of single-pass wet film thickness of 50-60 mu m, pass interval time of 3-8 min, and/or, The infrared gradient curing process comprises the steps of curing at 60 ℃ for 8-15 min, heating to 80 ℃, curing at 80 ℃ for 10-20 min, heating to 100 ℃ again, and curing at 100 ℃ for 10-25 min.
  10. 10. The method for spraying nano anticorrosive paint for chassis according to claim 7, wherein, The thickness of the coating is 120-150 mu m.

Description

Nano anti-corrosion coating for chassis, preparation method and spraying method thereof Technical Field The invention relates to the technical field of automobile spraying, in particular to a nano anti-corrosion coating for a chassis, a preparation method thereof and a spraying method thereof. Background The chassis corrosion protection technology has made significant progress in nanocomposite coatings and spray processes in recent years. From the material system, the prior art mainly adopts three solutions, namely a water-based epoxy system represented by China patent CN114926301A, salt fog resistance performance breakthrough for 2000 hours by adding graphene nano sheets (content of 0.5-2 wt%), a SiO 2 @ZnO core-shell structure system reported by ACS APPLIED MATERIALS & Interfaces (applied materials and Interfaces of American society), and a self-repairing system developed by China patent CN116656265A, wherein the corrosion resistance life is prolonged by utilizing the cathodic protection effect of ZnO, and the automatic repair of damaged parts is realized by a microencapsulated corrosion inhibitor. In terms of the spraying process, the prior art shows three development directions, namely ultrasonic-assisted electrostatic spraying of the Chinese patent CN115738936A (2023) can improve the dispersion uniformity of nano particles by 40%, 3D printing gradient coating technology reported in Additive Manufacturing (additive manufacturing) can realize accurate control of porosity, and a multi-angle robot spraying system recorded in the Chinese patent CN116102105A is suitable for a complex curved surface chassis structure. The closest prior art is a scheme of preheating a base material and low-temperature quick-drying water-based paint proposed by Chinese patent CN115433436A, the technology shortens the curing time to 30 minutes by preheating the base material to 60-80 ℃, the spraying efficiency is improved by 30 percent compared with the traditional technology, and the thickness deviation of the coating is controlled within +/-5 mu m. The technical progress not only remarkably improves the anti-corrosion performance, but also realizes cost reduction and synergy through technological innovation, and provides a more reliable solution for long-acting protection of the chassis. Through intensive analysis of the prior art, the following key defects are found that firstly, the cost of nano Materials such as graphene is high in terms of Materials, and as shown in researches of Materials & Design, nano particles are easy to agglomerate (the particle size is increased by 30-50%) in the storage and spraying processes, so that the spraying atomization effect is reduced (the atomization uniformity is reduced by 1 5-20%). Secondly, in terms of the process, the preheating process of chinese patent CN115433436a improves efficiency, but the energy consumption is up to 5.2 kw.h/m 2, and Journal of THERMAL SPRAY Technology (Journal of thermal spraying Technology) indicates that the applicability to heat sensitive nanomaterials (such as certain polymeric microcapsules) is limited. Furthermore, as described in Robotics and Computer-INTEGRATED MANUFACTURING (manufactured by integrating robots with computers), the programming of existing robotic spray systems is complex (48-72 hours of debugging is required on average) and studies in Manufacturing Letters (manufacturing flash) show that coating porosity increases dramatically (from 0.8% to 2.5%) when the spray speed exceeds 2 m/s. The root of the problems is that the surface modification technology of the nano material is imperfect (the modification efficiency of the existing silane coupling agent is only 60-70%), the optimization of the spraying process parameters lacks intelligent algorithm support, and the integration level of equipment systems is insufficient. It is particularly notable that the adaptability of the prior art to dynamic conditions (such as continuous vibration and salt spray alternation) is generally poor, and the ISO 20567-1 test shows that the weight loss of most coatings after 1000 cycles exceeds 15mg, which severely restricts the practical application effect of the chassis corrosion prevention technology. Therefore, aiming at the key problems of easy agglomeration of nano particles, slow curing of water-based paint, low spraying efficiency, high energy consumption, insufficient durability of a coating in a dynamic environment and the like existing in the current chassis anti-corrosion spraying technology, a novel nano anti-corrosion paint for a chassis, a preparation method thereof and a spraying method thereof are needed to be provided. Disclosure of Invention In order to solve the problems, the invention provides a nano anti-corrosion coating for chassis, a preparation method and a spraying method thereof, which firstly improves the uniformity of a coating by improving the nano material dispersing technology, and secondly, optimizing a curing process to short