CN-122011817-A - Low-temperature cured phosphate inorganic anticorrosive paint and preparation method thereof

CN122011817ACN 122011817 ACN122011817 ACN 122011817ACN-122011817-A

Abstract

The invention belongs to the technical field of inorganic anticorrosive paint, and discloses a low-temperature cured phosphate inorganic anticorrosive paint and a preparation method thereof. The coating comprises, by mass, 80-120 parts of aluminum phosphate binder, 5-18 parts of ZnO@SiO 2 core-shell structure curing agent, 0.1-8 parts of functional modified lamellar filler and 10-30 parts of deionized water. According to the invention, by constructing a ZnO@SiO 2 core-shell structure and utilizing the physical shielding effect of the SiO 2 shell layer, the release rate of Zn 2+ is delayed, the problem of bursting and cracking of a phosphate system in the low-temperature curing process is solved, and the stable curing of the coating at 80 ℃ is realized. Meanwhile, modified mica powder is introduced, the compatibility of the filler and the matrix is enhanced through interfacial chemical bonding, and the compactness and the adhesive force of the coating are obviously improved. The self-corrosion current density of the coating is reduced to 10 ‑8 A/cm 2 orders of magnitude, the adhesive force reaches 0 level, and the coating has excellent long-acting corrosion resistance.

Inventors

LIU XIAOYING
WANG YUNPENG
MA HAITAO
XU ZIQI

Assignees

大连理工大学

Dates

Publication Date: 20260512
Application Date: 20260331

Claims (8)

1. The low-temperature-cured phosphate inorganic anticorrosive paint is characterized by comprising the following components in parts by mass: 80-120 parts of aluminum phosphate binder; 5-18 parts of ZnO@SiO 2 core-shell structure curing agent; 0.1-8 parts of functional modified lamellar filler; 10-30 parts of deionized water.
2. The low-temperature-curable phosphate inorganic anticorrosive paint according to claim 1, wherein, In the aluminum phosphate binder, the molar ratio P/Al of phosphorus to aluminum is 2.5-3.5.
3. The low-temperature-curable phosphate inorganic anticorrosive paint according to claim 1, wherein, The ZnO@SiO 2 core-shell structure curing agent comprises an active core and an inorganic shell; the active core is at least one of nanoscale ZnO, nanoscale MgO and nanoscale CuO; The inorganic shell layer is at least one of SiO 2 、TiO 2 、Al 2 O 3 ; The mass ratio of the active core to the inorganic shell in the ZnO@SiO 2 core-shell structure curing agent is 1 (0.5-2.0).
4. The low-temperature-curable phosphate inorganic anticorrosive paint according to claim 1, wherein, The functional modified lamellar filler is at least one selected from modified mica powder, modified talcum powder and modified glass beads.
5. The low-temperature-curable phosphate inorganic anticorrosive paint according to claim 4, wherein, The functional modified lamellar filler is modified mica powder; the mesh number of the modified mica powder is 800-2000 mesh; The surface treatment agent adopted by the modified mica powder is a silane coupling agent; the silane coupling agent is at least one selected from KH550, KH560 and KH 570.
6. A method for preparing the low-temperature-curable phosphate inorganic anticorrosive paint according to any one of claims 1 to 5, comprising the steps of: (1) The preparation of the aluminum phosphate binder, namely diluting phosphoric acid to the required concentration, heating to 80 ℃, adding aluminum hydroxide powder according to the mole ratio of P/Al of 2.5-3.5, continuously stirring at constant temperature for reaction, cooling to room temperature after the solution is completely clear and transparent, and obtaining the aluminum phosphate binder for later use; (2) Firstly adding nano zinc oxide powder into absolute ethyl alcohol, performing ultrasonic treatment, sequentially adding ammonia water and deionized water under the condition of continuous stirring at room temperature, continuously aging, dripping a mixed solution of TEOS and absolute ethyl alcohol into a system under the condition of constant temperature continuous stirring, continuously maintaining constant temperature stirring for reaction, centrifuging, washing and drying the reaction solution to obtain the ZnO@SiO 2 core-shell curing agent; (3) Mixing and blending the aluminum phosphate binder and the ZnO@SiO 2 core-shell curing agent, namely adding the ZnO@SiO 2 core-shell curing agent into the aluminum phosphate binder, and continuously stirring until the ZnO@SiO 2 core-shell curing agent is uniformly distributed to obtain primary mixed slurry; (4) The preparation of the modified mica powder comprises the steps of firstly, dropwise adding glacial acetic acid into an ethanol water solution with the mass fraction of 90%, regulating the pH to be acidic, then dropwise adding a silane coupling agent, stirring at room temperature, adding the mica powder, carrying out ultrasonic dispersion treatment, then heating to 80 ℃ and continuously stirring, centrifuging, washing and drying a reaction solution to obtain the modified mica powder; (5) And (3) introducing and compounding the modified filler, namely adding the modified lamellar filler obtained in the step (4) and deionized water into the primary mixed slurry obtained in the step (3), and uniformly stirring to obtain the phosphate inorganic coating.
7. The method for preparing the low-temperature-cured phosphate inorganic anticorrosive paint according to claim 6, wherein in the step (2), the mass ratio of absolute ethyl alcohol, deionized water, ammonia water, zinc oxide and TEOS is 88:17:3:1:12.
8. The method for preparing a low-temperature-cured phosphate inorganic anticorrosive paint according to claim 6, wherein in the step (2), the mass ratio of the ethanol aqueous solution to the mica powder to the silane coupling agent is 80:1:0.1.

Description

Low-temperature cured phosphate inorganic anticorrosive paint and preparation method thereof Technical Field The invention belongs to the technical field of inorganic anticorrosive paint, and relates to a low-temperature cured phosphate inorganic anticorrosive paint and a preparation method thereof. Background The phosphate inorganic anticorrosive paint is used as an environment-friendly high-performance coating, and has great application potential in the heavy-duty corrosion prevention fields of aerospace, ocean engineering and large petrochemical facilities due to excellent chemical stability, high temperature resistance, high hardness and incombustibility. In the prior art system, the aluminum phosphate coating forms a three-dimensional network cross-linked structure mainly through the polycondensation reaction between the phosphate binder and the hardener, thereby realizing the protection of the metal substrate. However, because the polycondensation reaction generally requires a relatively high energy barrier, conventional phosphate coatings often rely on high temperature bakes above 200 ℃ to achieve adequate cure. The harsh process conditions greatly limit the application of the method to large immovable steel structures, field repair construction and heat-sensitive precise metal parts, and become key factors for restricting the development of the technical field. To reduce the curing temperature to accommodate a wider range of construction scenarios, researchers have attempted to introduce reactive curing agents into the system. Although the addition of highly active nanoscale zinc oxide is effective in catalyzing phosphate systems to cure at around 80 ℃, serious kinetic runaway problems are raised in practical applications. Because nano zinc oxide has extremely high surface energy and chemical alkalinity, extremely severe acid-base exothermic reaction occurs and explosion polymerization is initiated when the nano zinc oxide contacts with an acidic aluminum phosphate binder. The explosion phenomenon caused by local overheating causes the coating to generate huge internal stress at the initial stage of film formation, and the surface of the cured coating is often full of cracks in the macroscopic or microscopic level along with the rapid evaporation of physical moisture. These defects not only weaken the adhesion strength between the coating and the substrate, but also allow the external corrosive medium to penetrate directly to the surface of the metal matrix through cracks, resulting in a decrease in corrosion resistance. In addition, single inorganic film-forming systems often exhibit the disadvantages of great brittleness and insufficient compactness after curing. In order to improve barrier properties, the prior art often incorporates lamellar fillers. However, the lack of reactive functional groups on the surface of commonly used inorganic fillers that can chemically bond to phosphate matrices results in only a simple mechanical packing relationship between the filler and matrix. Such microscopic interfacial dislocation tends to form a continuous percolation path within the coating. Therefore, how to realize the controlled release and the slow release of the curing process through the structural design of the curing agent and to eliminate the interface defect by combining the surface functionalization modification of the filler is a technical problem to be solved in the current research and development of the high-performance low-temperature curing inorganic anticorrosive paint. Disclosure of Invention Aiming at the technical defects that the curing temperature of the phosphate anti-corrosion coating in the prior art is high (more than 200 ℃ is needed), or the coating is easy to generate internal stress cracking due to uncontrolled curing dynamics after an active curing agent is introduced, and the corrosive medium is easy to generate seepage due to weak bonding force between an inorganic filler and a matrix interface, the invention provides a low-temperature curing phosphate inorganic anti-corrosion coating and a preparation method thereof. According to the invention, by constructing the core-shell structure curing agent with the controlled release effect and the surface functionalized lamellar shielding filler, stable curing of the coating at 80 ℃ is realized, and the compactness and long-acting electrochemical protection capability of the coating are greatly improved. The technical scheme of the invention is as follows: the low-temperature cured phosphate inorganic anticorrosive paint comprises the following components in parts by mass: 80-120 parts of aluminum phosphate binder; 5-18 parts of ZnO@SiO 2 core-shell structure curing agent; 0.1-8 parts of functional modified lamellar filler; 10-30 parts of deionized water. Preferably, in the aluminum phosphate binder, the molar ratio P/Al of phosphorus to aluminum is 2.5-3.5; preferably, the aluminum phosphate binder has a P/Al molar ratio of 2.8