KR-20260065680-A - COMPOSITION FOR SURFACE TREATING COLD-ROLLED STEEL SHEET, COLD-ROLLED STEEL SHEET SURFACE TREATED BY USING THEREOF, AND MANUFACTURING METHOD THEREFOR

Abstract

The present invention relates to a composition for surface treatment of steel sheets, and more specifically, to a composition for surface treatment of cold-rolled steel sheets, a cold-rolled steel sheet surface-treated using said composition, and a method for manufacturing the same.

Inventors

• 최창훈
• 김진태
• 김종국
• 백두진
• 조수현

Assignees

• 주식회사 포스코

Dates

Publication Date

20260511

Application Date

20241101

Claims (15)

1. (a) Polymer resin: 5.0~40.0 wt%, (b) Curing agent: 1.0~8.0 wt%, (c) Co-solvent: 1.0~10.0 wt%, (d) pH adjuster: 1.0~5.0 wt%, (e) Inorganic rust inhibitor: 1.0~10.0 wt%, (f) Organic rust inhibitor: 0.1~3.0 wt%, (g) Water repellent: 0.1~3.0 wt%, (h) Surfactant: 0.01~2.00 wt%, and (i) Solution composition for surface treatment of cold-rolled steel sheets containing residual solvent.
2. In Article 1, The above polymer resin is a solution composition for surface treatment of cold-rolled steel sheets, comprising one or more selected from the group consisting of acrylic emulsion, polyethylene, acrylic acid-ethylene copolymer, and mixtures thereof.
3. In Article 1, The above curing agent is one or more selected from the group consisting of Highly Methylated Melamine Resins, Methylated High Imino Melamine Resins, Partially Methylated Melamine Resins, Highly Alkylated Melamine Resins, High Imino Melamine Resins, and mixtures thereof, in a solution composition for surface treatment of cold-rolled steel sheets.
4. In Article 1, The above-mentioned solvent is a solution composition for surface treatment of cold-rolled steel sheets, comprising one or more selected from the group consisting of butyl cellosolve, 2-butanol, ethanol, benzyl alcohol, diglyme, propylene glycol, ethylene glycol, and mixtures thereof.
5. In Article 1, The above pH adjuster is one or more selected from the group consisting of substances containing ammonia or ammonium salts and mixtures thereof, in a solution composition for surface treatment of cold-rolled steel sheets.
6. In Article 1, The above-mentioned inorganic anti-corrosion agent is a solution composition for surface treatment of cold-rolled steel sheets, comprising one or more selected from the group consisting of nano-particle colloidal silica, titanium oxide, cerium oxide, zirconium oxide, and mixtures thereof.
7. In Article 1, The above organic rust inhibitor is a solution composition for surface treatment of cold-rolled steel sheets, comprising one or more selected from the group consisting of benzothiazole, mercaptobenzothiazole (MBT), pyrimidine, benzotriazole, benzimidazole, 2H-indene-1,3-dione, and mixtures thereof.
8. In Article 1, The above-mentioned water-repellent agent is one or more selected from the group consisting of polydimethylsiloxane (PDMS), polyurethane, and mixtures thereof, in a solution composition for surface treatment of cold-rolled steel sheets.
9. In Article 1, The above surfactant is one or more selected from the group consisting of Tall oil fatty acid ethoxylate, Oleyl alcohol ethoxylate, Polyethylene Glycol- p -isooctylphenyl Ether, and mixtures thereof, in a solution composition for surface treatment of cold-rolled steel sheets.
10. In Article 1, The above solvent is water, and A solution composition for surface treatment of cold-rolled steel sheets, wherein the above water is one or more of pure water, distilled water, and deionized water.
11. Cold-rolled steel sheets; and The above cold-rolled steel sheet includes a surface treatment coating layer on at least one surface, and The above surface treatment coating layer is a surface-treated cold-rolled steel sheet in which the surface treatment coating layer is a coating layer formed from the composition of any one of claims 1 to 10.
12. In Paragraph 11, A surface-treated cold-rolled steel sheet having a surface treatment coating layer having a thickness of 0.1 to 2.0 μm (based on thickness after drying).
13. In Paragraph 11, When EDS measurement is performed on the surface of the surface treatment coating layer, the coating layer comprises, in weight percent, nitrogen (N): 1.0~15.0%, oxygen (O): 10.0~30.0%, silicon (Si): 10.0~20.0%, and the remainder being carbon (C) and other unavoidable impurities, a surface-treated cold-rolled steel sheet.
14. Step of preparing the steel sheet; A step of applying a solution composition to at least one surface of the above-mentioned steel sheet; and The method includes the step of drying and curing after applying the above solution composition, The above solution composition is a method for manufacturing a surface-treated cold-rolled steel sheet that is a composition of any one of claims 1 to 10.
15. In Paragraph 14, A method for manufacturing a surface-treated cold-rolled steel sheet, wherein the drying and hardening steps are performed in a temperature range of 50 to 270°C based on the peak metal temperature (PMT) of the steel sheet.

Description

Composition for surface treatment of cold-rolled steel sheets, cold-rolled steel sheet surface treated using the same, and method for manufacturing the same The present invention relates to a composition for surface treatment of steel sheets, and more specifically, to a composition for surface treatment of cold-rolled steel sheets, a cold-rolled steel sheet surface-treated using said composition, and a method for manufacturing the same. Steel sheets are used in various industries due to their excellent mechanical properties, but because they are susceptible to corrosion, galvanized steel sheets that can provide sacrificial protection are generally used. Meanwhile, in some cases, unplated cold-rolled steel sheets are used. Since surface corrosion can occur if these cold-rolled steel sheets are exposed to the atmosphere during distribution and manufacturing, they are generally distributed with rust-preventive oil applied to their surface to prevent this. The rust-preventive oil applied to the surface of the cold-rolled steel must be removed through a degreasing process before the final part is manufactured; however, this inevitably leads to increased costs due to the additional process and poses problems such as environmental pollution due to the characteristics of the degreasing solution. Accordingly, there is a need for the development of technology that can secure the corrosion resistance of cold-rolled steel sheets while eliminating processes such as the application of rust-preventive oil, which are essential for the distribution of cold-rolled steel sheets. FIG. 1 illustrates an example of a cold-rolled steel sheet having a coating layer applied with a surface treatment composition according to one embodiment of the present invention. Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided to more fully explain the invention to those with average knowledge in the relevant technical field. In drawings, the shapes and sizes of elements may be exaggerated for clearer explanation. In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form. In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described. Unless otherwise specifically defined in the specification of the present invention, % units mean weight %. The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention. The inventors of the present invention recognized the problem arising from the requirement for an additional process to remove rust-preventive oil for the production of a final product when applying rust-preventive oil, which is generally performed for the distribution of steel sheets, particularly cold-rolled steel sheets, and conducted in-depth research to solve this problem. As a result, a composition suitable for surface treatment of cold-rolled steel sheets was provided, and it was confirmed that a cold-rolled steel sheet with improved corrosion resistance and surface conductivity during surface treatment could be obtained using this composition, thereby completing the present invention. The present invention will be de