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CN-122006994-A - Preparation method of ultra-smooth anti-corrosion coating on surface of tinplate

CN122006994ACN 122006994 ACN122006994 ACN 122006994ACN-122006994-A

Abstract

A preparation method of a tin plate surface ultra-smooth anti-corrosion coating comprises the steps of firstly, taking the tin plate as a cathode, performing electrodeposition in a tin-containing hydrochloric acid electrolyte until a continuous tin deposition layer is formed on the tin plate surface, then sequentially cleaning and drying the tin plate to obtain the tin plate with the tin deposition layer on the surface, secondly, firstly, soaking the tin plate with the tin deposition layer on the surface in a dopamine solution to form a continuous polydopamine adhesion layer on the surface, drying to obtain an intermediate, then, soaking the intermediate in a modified solution to form a continuous ultra-hydrophobic layer on the surface of the intermediate, drying to obtain the tin plate with the ultra-hydrophobic layer on the surface, and thirdly, coating oil gel on the tin plate with the ultra-hydrophobic layer on the surface, and after curing, forming the ultra-smooth anti-corrosion coating on the tin plate surface. Therefore, the coating of the design can maintain stable corrosion resistance for a long time.

Inventors

  • LI KE

Assignees

  • 中远海运能源运输股份有限公司

Dates

Publication Date
20260512
Application Date
20260106

Claims (10)

  1. 1. A preparation method of a super-smooth anti-corrosion coating on a tinplate surface is characterized by comprising the following steps of: firstly, electrodepositing tin serving as a cathode in tin-containing hydrochloric acid electrolyte until a continuous tin deposition layer is formed on the surface of the tin, taking out the tin after the electrodepositing treatment, and sequentially cleaning and drying to obtain the tin with the tin deposition layer on the surface; The tin-containing hydrochloric acid electrolyte comprises bivalent tin ions, wherein the concentration of the tin ions is 0.015mol/L-0.025mol/L; Soaking the tinplate with the tin deposition layer on the surface in a dopamine solution until a continuous polydopamine adhesion layer is formed on the surface of the tin deposition layer, taking out the tinplate soaked in the dopamine solution and drying to obtain an intermediate with the polydopamine adhesion layer on the surface; The modifying solution comprises ethanol and dodecyl mercaptan; And thirdly, coating the surface of the tinplate with the super-hydrophobic layer with oil gel until the oil gel layer covering the super-hydrophobic layer is formed, so that the super-smooth anti-corrosion coating is obtained on the surface of the tinplate.
  2. 2. The method for preparing the ultra-smooth anti-corrosion coating on the surface of the tinplate, which is characterized by comprising the following steps of: in the first step, the tin-containing hydrochloric acid electrolyte is prepared by the following steps: Firstly, snCl 2 is dissolved in water to obtain a SnCl 2 aqueous solution, then concentrated hydrochloric acid is added into the SnCl 2 aqueous solution to obtain a mixed solution A, and the mixed solution A is stirred until the mixed solution A is uniformly clarified to obtain the tin-containing hydrochloric acid electrolyte.
  3. 3. The method for preparing the ultra-smooth anticorrosive coating for the tinplate surface according to claim 2, wherein the concentration of the SnCl 2 aqueous solution is 0.455g/100ml to 0.465g/100ml; the mass fraction of the concentrated hydrochloric acid is 36% -38%; The volume ratio of the concentrated hydrochloric acid to the SnCl 2 aqueous solution is 0.25-0.35:100.
  4. 4. The method for preparing the ultra-smooth anti-corrosion coating on the surface of the tinplate, which is characterized by comprising the following steps of: in the second step, the dopamine solution is prepared by: Adding Tris-HCl buffer solution and dopamine hydrochloride into water to obtain a mixed solution B, and stirring the mixed solution B until the mixed solution B forms a uniform and clear solution to obtain a dopamine solution.
  5. 5. The method for preparing the ultra-smooth anticorrosive coating for the surface of the tinplate, which is characterized by comprising the following steps of (1) preparing the ultra-smooth anticorrosive coating for the surface of the tinplate according to claim 4, wherein the volume ratio of the Tris-HCl buffer solution to water is 0.09-0.11:10; the concentration of the dopamine hydrochloride in the dopamine solution is 1.8g/L-2.2g/L.
  6. 6. The method for preparing the ultra-smooth anti-corrosion coating on the surface of the tinplate, which is characterized by comprising the following steps of: In the second step, the modifying solution is prepared by: Mixing ethanol and dodecyl mercaptan, and stirring until a uniform and clear solution is formed, thus obtaining a modified solution.
  7. 7. The method for preparing a coating for preventing corrosion on a tin plate surface according to claim 6, wherein the volume ratio of the ethanol to the dodecyl mercaptan is 49-51:0.95-1.05.
  8. 8. The method for preparing a coating for preventing corrosion on a tin plate surface according to claim 1, wherein in the third step, the oleogel comprises sunflower seed oil and white beeswax; the mass ratio of the sunflower seed oil to the white beeswax is 8.9-9.1:1.
  9. 9. The method for preparing the ultra-smooth anti-corrosion coating on the surface of the tinplate according to any one of claims 1 to 8, which is characterized in that: In the second step, the step of immersing the tin plate with the tin deposition layer on the surface in the dopamine solution until the continuous polydopamine adhesion layer is formed on the surface of the tin deposition layer means that: And immersing the tinplate with the tin deposition layer on the surface in a dopamine solution for 12-15 hours to form a continuous polydopamine adhesive layer on the surface of the tin deposition layer.
  10. 10. The method for preparing the ultra-smooth anti-corrosion coating on the surface of the tinplate according to any one of claims 1 to 8, which is characterized in that: in the second step, the step of immersing the intermediate in the modifying solution until the surface of the polydopamine adhesive layer forms a continuous super-hydrophobic layer means that: and (3) soaking the intermediate in the modified solution for 30-35 minutes, and forming a continuous super-hydrophobic layer on the surface of the polydopamine adhesive layer.

Description

Preparation method of ultra-smooth anti-corrosion coating on surface of tinplate Technical Field The invention relates to a preparation method of a tinplate surface coating, belongs to the field of metal surface treatment, and particularly relates to a preparation method of a tinplate surface ultra-smooth anti-corrosion coating. Background Tin plate (tin plate) is widely used for food packaging can body due to its good sealing property, formability and mechanical strength, and its surface corrosion can damage the integrity of can body, pollute content, and possibly cause heavy metal ion migration, seriously jeopardizing food safety. At present, corrosion prevention of a tinplate tank body is mainly realized by coating an organic coating (such as epoxy and phenolic resin) on the surface of the tinplate, however, on one hand, the bonding between the organic coating and a tinplate substrate mainly depends on physical adsorption and limited mechanical interlocking, the interface adhesion force is limited, foaming or peeling easily occurs under processing or heating stress, and on the other hand, corrosive ions (especially corrosive ions containing H +、Cl- and the like) in the content gradually permeate through microscopic defects of the coating during long-term storage and finally reach a metal interface to cause corrosion, so that the coating has difficulty in keeping stable corrosion prevention performance for a long time. The application number is 202011068306.2, the application date is China patent application of 2020, 10 months and 08 days, a preparation method of an electrodeposition method for preparing a wear-resistant super-hydrophobic coating is disclosed, firstly, a stainless steel substrate is polished and treated, then zinc sulfate electrolyte, potassium chloride electrolyte and dopamine hydrochloride electrolyte with certain concentration are prepared and fully and uniformly stirred, then the treated stainless steel substrate is used as a cathode, a copper plate with the same size is used as an anode, the voltage is set to be 10-30V, and the deposition time is 10-60 minutes, so that the final super-hydrophobic zinc/polydopamine/n-dodecyl mercaptan coating is obtained. Although this patent may promote a certain wear resistance, it still has the following drawbacks: The superhydrophobic function of the design depends on the fragile micro-nano structure of the surface, and the structure is easy to lose effect under mechanical action or long-term soaking, so that the coating still has difficulty in keeping stable anti-corrosion performance for a long time. The disclosure of this background section is only intended to increase the understanding of the general background of the present patent application and should not be taken as an admission or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art. Disclosure of Invention The invention aims to overcome the defect and the problem that the coating in the prior art is difficult to maintain stable anti-corrosion performance for a long time, and provides a preparation method of a tin plate surface ultra-smooth anti-corrosion coating with the coating capable of maintaining stable anti-corrosion performance for a long time. In order to achieve the purpose, the technical scheme of the invention is that the preparation method of the ultra-smooth anti-corrosion coating on the surface of the tinplate comprises the following steps: firstly, electrodepositing tin serving as a cathode in tin-containing hydrochloric acid electrolyte until a continuous tin deposition layer is formed on the surface of the tin, taking out the tin after the electrodepositing treatment, and sequentially cleaning and drying to obtain the tin with the tin deposition layer on the surface; The tin-containing hydrochloric acid electrolyte comprises bivalent tin ions, wherein the concentration of the tin ions is 0.015mol/L-0.025mol/L; Soaking the tinplate with the tin deposition layer on the surface in a dopamine solution until a continuous polydopamine adhesion layer is formed on the surface of the tin deposition layer, taking out the tinplate soaked in the dopamine solution and drying to obtain an intermediate with the polydopamine adhesion layer on the surface; The modifying solution comprises ethanol and dodecyl mercaptan; And thirdly, coating the surface of the tinplate with the super-hydrophobic layer with oil gel until the oil gel layer covering the super-hydrophobic layer is formed, so that the super-smooth anti-corrosion coating is obtained on the surface of the tinplate. In the first step, the tin-containing hydrochloric acid electrolyte is prepared by the following steps: Firstly, snCl 2 is dissolved in water to obtain a SnCl 2 aqueous solution, then concentrated hydrochloric acid is added into the SnCl 2 aqueous solution to obtain a mixed solution A, and the mixed solution A is stirred until the mixed solution A is u