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CN-121975401-A - Magnetic-guiding permeation type epoxy rust-fixing coating composition and preparation method and application thereof

CN121975401ACN 121975401 ACN121975401 ACN 121975401ACN-121975401-A

Abstract

The invention belongs to the technical field of epoxy resin coatings, and particularly relates to a magnetic-guide penetration type epoxy rust-fixing coating composition, a preparation method and application thereof. The magnetic guide penetration type epoxy rust fixing coating composition comprises, by weight, 40-60 parts of an epoxy resin base material, 5-15 parts of a reactive diluent, 3-8 parts of surface modified nano Fe 3 O 4 magnetic particles, 10-25 parts of a curing agent and 1-5 parts of an auxiliary agent, wherein the surface modified nano Fe 3 O 4 magnetic particles are uniformly dispersed in an epoxy resin system after being subjected to surface modification of oleic acid or citric acid, and the epoxy resin base material has good dispersion stability and magnetic responsiveness. The invention creatively combines magnetic nano particles with external magnetic field guidance, moves along the surface of rusted steel bars through a strong magnetic field device before the coating is solidified, and utilizes the magnetic response characteristic of the magnetic particles to drag epoxy resin to actively permeate into capillary pores of the rusted steel bars so as to realize deep sealing of the rusted steel bars.

Inventors

  • PANG BO
  • GAO JIANGUO
  • ZHANG WEI
  • YUAN LIANWANG
  • ZHAO LINGLING
  • JIN ZUQUAN
  • MA JIHUA
  • WANG ZHIYONG
  • CHEN YIDONG
  • SONG XIAOYUN
  • LIU YONG
  • LIU LIRONG

Assignees

  • 青岛理工大学
  • 江苏启青新型材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260112

Claims (10)

  1. 1. The magnetic guide penetrating type epoxy rust fixing coating composition is characterized by comprising, by weight, 40-60 parts of an epoxy resin base material, 5-15 parts of an active diluent, 3-8 parts of surface modified nano Fe 3 O 4 magnetic particles, 10-25 parts of a curing agent and 1-5 parts of an auxiliary agent, wherein the particle size of the surface modified nano Fe 3 O 4 magnetic particles is 20-100nm, and the saturation magnetization is 50-80emu/g.
  2. 2. The magnetically permeable epoxy rust fixing coating composition of claim 1, wherein the surface modified nano Fe 3 O 4 magnetic particles are prepared by a method comprising the steps of: Step 1, connecting And (3) with Dissolving in deionized water according to a molar ratio of 2:1, heating to 50-80 ℃ under the protection of nitrogen, and uniformly stirring to obtain an iron salt mixed solution; Step 2, slowly dripping ammonia water or sodium hydroxide solution into the ferric salt mixed solution, adjusting the pH value to 9-11, and continuously stirring and reacting for 20-60min to generate nano Fe 3 O 4 particles; And 3, immediately adding a surface modifier to perform in-situ surface modification after nano Fe 3 O 4 particles are generated, and performing magnetic separation and cleaning after continuing to react for 30-60min to obtain the surface modified nano Fe 3 O 4 magnetic particles.
  3. 3. The magnetically permeable epoxy rust fixing coating composition of claim 2, wherein the surface modifier is oleic acid, and the addition amount is 10% -30% of the mass of the nano Fe 3 O 4 particles; The step 3 also comprises transferring the nano Fe 3 O 4 particles modified by oleic acid into an organic solvent by a phase transfer method to form oily magnetic dispersion liquid.
  4. 4. The magnetically permeable epoxy rust fixing coating composition of claim 2, wherein the surface modifier is citric acid and the addition amount is 5% -20% of the mass of the nano Fe 3 O 4 particles; And step 3, dispersing the nano Fe 3 O 4 particles modified by the citric acid in deionized water to form aqueous magnetic dispersion liquid.
  5. 5. The magnetically permeable epoxy rust fixing coating composition of claim 1, wherein the epoxy resin base material is any one or a mixture of a bisphenol a epoxy resin, a bisphenol F epoxy resin and a phenolic epoxy resin, and the epoxy equivalent of the epoxy resin base material is 180-500g/eq; the reactive diluent is at least one of butyl glycidyl ether, phenyl glycidyl ether, 1, 4-butanediol diglycidyl ether and C12-C14 alkyl glycidyl ether.
  6. 6. The magnetically permeable epoxy rust fixing coating composition of claim 1, wherein the curing agent is a neutral or weakly basic curing agent having a pH of 6.5-9.0.
  7. 7. The magnetically permeable epoxy rust fixing coating composition of claim 1, wherein the auxiliary agent comprises any one or a mixture of several of defoamer, leveling agent, coupling agent and anti-settling agent; Preferably, the auxiliary agent comprises 0.1-0.5 part of defoaming agent, 0.2-1 part of leveling agent, 0.5-2 parts of coupling agent and 0.2-1.5 parts of anti-settling agent in parts by weight; more preferably, the defoaming agent is an organosilicon defoaming agent, the leveling agent is an acrylic ester leveling agent, the coupling agent is a silane coupling agent KH-550 or KH-560, and the anti-settling agent is fumed silica or organic bentonite.
  8. 8. The preparation method of the magnetic guide penetration type epoxy rust fixing coating composition is characterized by comprising the following steps of: S1, dispersing surface modified nano Fe 3 O 4 magnetic particles in an active diluent to obtain a magnetic dispersion liquid; s2, heating the epoxy resin base material to 40-60 ℃, adding the magnetic dispersion liquid, and uniformly stirring to obtain a magnetic epoxy resin main agent; s3, adding the auxiliary agent into the magnetic epoxy resin main agent, and uniformly stirring to obtain a component A; S4, independently packaging the curing agent into a component B; And S5, uniformly mixing the component A and the component B according to a proportion to obtain the magnetic guide penetration type epoxy rust fixing coating composition.
  9. 9. Use of a magnetically permeable epoxy rust-fixing coating composition according to any one of claims 1 to 7 for rust-fixing protection of rust-reinforcing steel bars.
  10. 10. The use according to claim 9, comprising the following process steps: p1, pretreating the surface of the rusted steel bar to remove floating rust and greasy dirt; p2, coating the magnetic guide penetration type epoxy rust fixing coating composition on the surface of the rusted steel bar; p3, before the coating is dried, using an external strong magnetic field device with the surface magnetic field intensity of 0.3-0.8T to move along the gap direction of the surface of the steel bar or the rust layer; p4, curing at room temperature or heating to form a compact protective layer; preferably, in the step P3, the moving speed of the external strong magnetic field device is 1-10cm/s, and the moving times are 2-5 times; the pretreatment method in the process P1 is manual rust removal to St2 level or power tool rust removal to St3 level, and the thickness of the rust layer is kept to be 50-150 mu m; the coating mode is any one of brushing, roller coating or spraying, the number of coating channels is 1-3, and the interval time of each channel is 2-6h.

Description

Magnetic-guiding permeation type epoxy rust-fixing coating composition and preparation method and application thereof Technical Field The invention belongs to the technical field of epoxy resin coatings, and particularly relates to a magnetic-guide penetration type epoxy rust-fixing coating composition, a preparation method and application thereof. Background The reinforced concrete structure is widely applied to the infrastructure engineering of bridges, wharfs, ocean platforms, tunnels, buildings and the like due to the excellent mechanical properties and economy. However, in the service process, the problem of corrosion of the reinforced steel bar is increasingly prominent due to the factors such as carbonization of the concrete, erosion of chloride ions, stray current and the like, and the corrosion of the reinforced steel bar becomes one of main diseases affecting the durability and the safety of the reinforced concrete structure. The economic loss of reinforcing steel bars caused by corrosion is counted to be up to billions of dollars each year worldwide, so the research of the reinforcing steel bar corrosion prevention repair technology has important engineering significance and economic value. Aiming at the protection and repair of rusted steel bars, the traditional method mainly comprises the steps of thoroughly rust removing, coating an anti-corrosion coating, cathodic protection, electrochemical dechlorination and the like. The thorough rust removal method has the advantages of reliable effect, high construction difficulty, high cost and long construction period, and is difficult to implement for the steel bars in the poured concrete. Therefore, the technology of the rust fixing coating for the construction with rust has the core thought that under the condition of keeping part of the rust layer, the rust layer is sealed and isolated by the coating, so that the further development of the rust is inhibited. Currently, rust-fixing coatings commonly used in the market mainly comprise epoxy, alkyd, acrylic and the like. Among them, epoxy-based rust-fixing coatings are widely used due to their excellent adhesion, chemical resistance and mechanical strength. However, the conventional epoxy rust-fixing coating has the technical bottlenecks that firstly, the permeability is insufficient, the epoxy resin is difficult to penetrate into the micro-pore structure in the rust layer due to the large molecular weight and high viscosity of the epoxy resin, a sealing film can be formed on the surface of the rust layer, so that corrosion reaction at the interface between the bottom of the rust layer and a steel bar substrate is still likely to continue, secondly, the rust layer has a complex structure, and rust products (mainly alpha-FeOOH, beta-FeOOH, gamma-FeOOH and gamma-FeOOHAnd the like) to form a loose porous layered structure, wherein the porosity is as high as 30% -50%, the traditional coating is difficult to effectively fill and seal the capillary pores, the interfacial binding force is weak, the physical adsorption effect between the coating and the rust layer is limited, and stripping failure is easy to occur under service environments such as damp-heat alternation, freeze thawing cycle and the like. To improve the permeability of epoxy coatings, researchers have tried several approaches, such as adding reactive diluents to reduce the viscosity of the system, but excessive use can affect the water resistance and mechanical strength of the coating. For example, the fluidity can be improved by using a low molecular weight epoxy resin, but the crosslinking density after curing is reduced, and the protective performance is lowered. In recent years, the modification technology of nano materials becomes a research hot spot, nano fillers such as nano SiO 2, nano TiO 2, nano ZnO, graphene and the like are introduced into an epoxy coating system, and the compactness and the barrier property of the coating can be improved to a certain extent by utilizing the small-size effect and the high specific surface area of nano particles. However, the nano-modified coating is still a passive barrier mechanism in nature, i.e. the penetration of corrosive media is blocked by means of the dense structure of the coating itself, rather than actively penetrating into the rust layer to achieve deep sealing. In summary, the existing epoxy rust-fixing coating technology has the common problems of limited penetration depth and poor deep sealing effect, and particularly aims at the rust-fixing application scene of rust-carrying construction of rusted steel bars, so that development of a novel coating material capable of actively penetrating into a rust layer and realizing deep sealing rust fixing and a construction method are needed. Disclosure of Invention The invention aims to provide a magnetic guide penetration type epoxy rust fixing coating composition, a preparation method and application thereof, which are beneficial to solving