Chromium-free tinning plate and surface treatment method thereof

Abstract

The invention relates to the technical field of tinning plates, in particular to a chromium-free tinning plate and a surface treatment method thereof. The chromium-free tinning plate comprises a steelbase plate, a tinning layer and a coating layer; the tinning layer is passivated on the steel base plate through a phosphate solution; and the coating layer is bonded to the passivated tinning layerthrough coating equipment. Because in the tinning process of the steel base plate, the phosphate solution is selected for passivation treatment to avoid environmental pollution caused by chromate passivatin, after the passivation of the phosphate solution, the quality of the tinning plate is affected, and the requirements of oxidation resistance and corrosion resistance of the tinning plate cannotbe met; and thus, through the coating layer arranged on the tinning layer, a chromate solution in the passivation process of the tinning plate is replaced by the phosphate solution, so as to avoid the pollution of the chromate to the environment, meanwhile the coating layer is arranged to protect the chemical stability of the surface of the tinning plate passivated by phosphate, and the use effect of the chromium-free tinning plate is maintained.

Description

technical field [0001] The invention relates to the technical field of tinplate, in particular to a chromium-free tinplate and a surface treatment method thereof. Background technique [0002] Tin plate refers to a cold-rolled thin steel plate coated with a layer of extremely thin metal tin on both sides. It combines the hardness and strength of steel with the easy weldability, corrosion resistance and bright appearance of tin; Toxicity, light weight, easy processing and molding, etc., so it has been widely used in food can industry, electronic devices, chemical paint and other industries. In order to improve the chemical stability of tinplate, the surface of tinplate should be passivated. ; For an introduction to the passivation treatment of tinplate, please refer to: Luo Gong et al., Research Progress on Passivation of Environmentally Friendly Tinplate [J], Electroplating and Finishing, 2015(No.19).1128-1132. [0003] Chromium passivation treatment of tinplate is a mature...

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Problems solved by technology

[0004] There are also some technical solutions about chromium-free tinplate and its surface treatment method in the prior art. For example, a Chinese patent with application number 2015108542830 discloses a chromium-free surface-treated tinplate, its production method and surface treatment method. Treatment agent: by coating the surface of the tinplate with an environmentally friendly water-based surface treatment agent containing 0.1-5wt% zinc salt, 0.1-5wt% zirconium salt or molybdenum salt, 5-30wt% siloxane or polysiloxane On the surface of the tin layer, a chromium-free passive film with uniform and dense composition, good performance and stability is formed. The passivation film contains 0.1-20mg / m2 of zinc, 0.1-20mg / m2 of zirconium or molybdenum, 0.5- 100mg / m2 of silicon, the passivation film in this technical solution can endow the surface of the tinplate with excellent surface stability, corrosion resistance and paint film adhesion, and it is safe for food contact. The performance of the tinplate can be achieved Comparable to chromium passivation, its production process does not use chromate, making the tinplate production process truly green and in line with increasingly stringent environmental regulations; however, the zinc compound contained in the zinc salt in this technical solution will also affect the environment Pollution; making the chromium-free surface treatment tinplate, its production method and surface treatment agent in this technical solution not environmentally friendly enough

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