A blue coloring agent for weathering steel rust layer and its use method

Abstract

The present invention relates to a blue coloring treatment agent for weathering steel rust layer and a method for using the same. The coloring treatment agent is composed of a pretreatment agent and a coloring agent. The pretreatment agent is composed of: citric acid: 19-48 g / L, inorganic acid: 1.5-10 g / L, copper salt: 8-25 g / L, nickel salt: 3.9-12 g / L, auxiliary agent: 0.05-0.08 g / L, and the balance is water; the coloring agent is composed of: ferrocyanide: 45-147 g / L, penetrant: 2.5-10 g / L, and the balance is water. The surface of the weathering steel treated with the treatment agent of the present invention presents a blue color and has a good decorative appearance, providing a solution for the color performance and application scenario expansion of the coating-free weathering steel. The blue coloring treatment agent is water-based and does not contain harmful components such as volatile organic matter and hexavalent chromium. The coloring treatment has a simple implementation process and low construction cost, and is suitable for implementation at the construction site of weathering steel components.

Description

Technical Field

[0001] The invention belongs to the field of corrosion science and relates to a steel plate surface treatment agent, and specifically refers to a blue coloring treatment agent for a weathering steel rust layer and a use method thereof. Background Art

[0002] Weathering steel has good atmospheric corrosion resistance. During use, a dense and stable rust layer can be formed on its surface. This rust layer has good corrosion resistance and can effectively prevent the entry of corrosive media. The paint-free use of weathering steel eliminates the need for painting and regular anti-corrosion treatment, so it can produce good economic and environmental benefits. At present, the paint-free use of weathering steel has been extended to outdoor weathering steel structures and indoor building interior walls and landscapes. However, there are also some problems when using weathering steel without painting. It takes 4 to 10 years for the formation of a stable rust layer on the surface of weathering steel under outdoor service. Before that, the exposed weathering steel, like ordinary carbon steel, produces loose rust layers and rust liquid such as red rust and yellow rust. The rust liquid flows and scatters, affecting the appearance and polluting the environment. In addition, in actual applications, the destruction of the rust layer caused by welding, mechanical damage, pollution and other reasons will seriously affect the appearance of weathering steel components.

[0003] At present, some rust stabilization treatment agents for the surface of weathering steel have been developed to address the problem of rust dripping in the early stage of exposed use of weathering steel. The development of these technologies has expanded the application areas of weathering steel without painting. However, in actual applications, the rust layer on the surface of weathering steel after stabilization treatment is brown or brown, and the color is relatively single. It cannot provide rich colors in application scenarios such as cities and landscapes, making it unable to form a good color and aesthetic coordination with the surrounding environment. The above disadvantages limit the further expansion of the application areas of exposed use of weathering steel and rust stabilization treatment technology. Some research has been conducted in this field. Patent CN107858672A discloses a treatment liquid for regulating the color of the rust layer on the surface of weathering steel and a treatment method thereof. The treatment liquid includes a precursor liquid for coloring the corrosion of the weathering steel surface and a stabilizing liquid for consolidating the color of the rust layer obtained after the corrosion of the weathering steel surface. The precursor liquid includes any one or any two or more of the precursor liquid A liquid that makes the rust layer on the surface of the weathering steel red, the precursor liquid B liquid that makes the rust layer on the surface of the weathering steel yellow, and the precursor liquid C liquid that makes the rust layer on the surface of the weathering steel bluish red. This invention uses the principle that any color can be formulated by composite regulation of the three primary colors. The precursor liquid and the stabilizing liquid are sequentially sprayed on the surface of the weathering steel. The treated rust layer on the surface of the weathering steel has a more beautiful visual effect without applying a coating, and the color of the rust layer has the advantages of being controllable according to the composite principle of the three primary colors. However, the treatment liquid contains several precursor liquids, each of which has a corresponding stabilizing liquid. The precursor liquid needs to be sprayed on the surface of the steel plate three or four times or more, and then the corresponding stabilizing liquid needs to be sprayed twice or three times or more. When color mixing is performed, three precursor liquids and their corresponding stabilizing liquids need to be sprayed alternately. The entire treatment process is time-consuming and cumbersome, which is not conducive to practical application. Patent CN108754474A reports a treatment liquid for accelerating the stabilization of the rust layer of weathering steel, the treatment liquid is composed of a promoter, an organic acid, a colorant, and an auxiliary agent; the promoter is one or more of magnesium sulfate, iron sulfate and copper sulfate; the organic acid is one or more of phytic acid, carboxylic acid and tannic acid; the colorant is one or more of selenium dioxide, selenium trioxide and selenous acid; the auxiliary agent is one or more of sodium chloride, sodium fluoride and potassium chloride. The treatment liquid and the treatment method can make the rust layer appear blue, orange and other colors, and at the same time avoid the phenomenon of surface rust liquid sagging. However, the selenium dioxide and selenious acid contained in the colorant of the treatment agent are extremely toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment. Patent CN113930753A reports a hot-rolled weathering steel rust layer stabilization treatment agent and treatment method treatment agent, which is divided into a pre-treatment component and a post-treatment component; the pre-treatment component is pickling waste liquid containing Fe 3+ , Fe 2 + , Cl -Plasma; the post-treatment component contains K2Cr2O7, Sb(NO3)3, SnSO4, etc. After the treatment, the surface of the hot-rolled weathering steel changes from iron oxide to brown rust. The color of the rust layer after the treatment is still the same as that of rust, and the pre-treatment component needs to be heated to 50-70℃ and the post-treatment component needs to be heated to 70-90℃ before use, which limits its application on the construction site. The pre-treatment component contains hexavalent chromium and is prone to produce irritating acid mist after heating, which limits its applicability in construction. Summary of the invention

[0004] The purpose of the present invention is to address the shortcomings of the existing methods and provide a blue coloring agent for the rust layer of weathering steel and a method of using the same, which is used for the surface of weathering steel that is naturally rusted or covered with a rust layer after rust stabilization treatment, so as to achieve the purpose of coloring the rust layer. The surface of the weathering steel treated with the treatment agent appears blue and has a good decorative appearance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A blue coloring treatment agent for a weathering steel rust layer, the coloring treatment agent consists of a pretreatment agent and a coloring agent, the pretreatment agent consists of: 19-48 g / L of citric acid, 1.5-10 g / L of inorganic acid, 8-25 g / L of copper salt, 3.9-12 g / L of nickel salt, 0.05-0.08 g / L of auxiliary agent, and the balance is water (total amount is one liter); the coloring agent consists of: 45-147 g / L of ferrocyanide, 2.5-10 g / L of penetrant, and the balance is water (total amount is one liter).

[0007] The citric acid in the pretreatment agent is a ternary organic weak acid, which can react with the rust layer on the surface of the weathering steel plate to form a chelate of iron ions, so that the concentration of iron ions remains relatively stable when participating in the chemical reaction of the coloring process, thereby improving the coloring effect.

[0008] The inorganic acid is one or both of hydrochloric acid and sulfuric acid, and its function is to quickly generate iron ions on the surface of weathering steel and provide favorable acidic conditions for chemical reactions in the coloring process.

[0009] The copper salt is one or both of CuCl2 and CuSO4, and its function is to introduce the corrosion-resistant alloy element Cu into the rust layer of the weathering steel after coloring, and at the same time improve the stability of the coloring chemical reaction product.

[0010] The nickel salt is one or both of NiCl2 and NiSO4, and its function is to introduce the corrosion-resistant alloy element Ni into the rust layer of the weathering steel after coloring, and at the same time improve the stability of the coloring chemical reaction product.

[0011] The auxiliary agent is one or more of fatty alcohol polyoxyethylene ether, alcohol ether phosphate, and sodium dodecyl sulfate. The rust layer on the surface of the weathering steel is microscopically rough and loose. The function of the auxiliary agent is to improve the wettability of the surface of the weathering steel and enable the pretreatment agent to fully react with the surface of the weathering steel.

[0012] The ferrocyanide is one of K4[Fe(CN)6] and Na4[Fe(CN)6]. Ferrocyanide is the main component of the colorant and can react with iron ions on the surface of weathering steel to generate a blue coordination compound. The coordination compound has the characteristics of being non-toxic and having good color stability.

[0013] The penetrant is sodium chloride, which functions to improve the permeability of the colorant in the rust layer of weathering steel, so that the colorant fully penetrates into the microstructure of the rust layer and improves the coloring effect.

[0014] A method for using a blue coloring agent for a rust layer of weathering steel. When using the coloring agent for coloring, first spray or brush the pretreatment agent on the rusty weathering steel surface free of dust, grease and other dirt, then spray or brush the coloring agent on the weathering steel surface that has not yet dried, and repeat the above steps after the weathering steel surface is completely dry until the rust layer presents a blue color.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The surface of weathering steel treated with this treatment agent appears blue, with a good decorative appearance, providing a solution for the color performance and application scenario expansion of unpainted weathering steel. The blue coloring treatment agent is water-based and does not contain harmful ingredients such as volatile organic compounds and hexavalent chromium. The coloring treatment process is simple and the construction cost is low, which is suitable for implementation at the construction site of weathering steel components. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the specific implementation methods of the present invention are further described below in conjunction with embodiments. The following embodiments are used to specifically illustrate the contents of the present invention. These embodiments are only general descriptions of the contents of the present invention and do not limit the contents of the present invention.

[0018] The embodiments and comparative examples of the present invention are shown in Table 1 (contents are all in g / L).

[0019] Table 1 Examples of the present invention and comparative examples

[0020] Citric Acid hydrochloric acid sulfuric acid <![CDATA[CuCl2]]> <![CDATA[CuSO4]]> <![CDATA[NiCl2]]> <![CDATA[NiSO4]]> Additives <![CDATA[K4[Fe(CN)6]]]> <![CDATA[Na4[Fe(CN)6]]]> Sodium chloride Example 1 19 9 25 3.9 0.06 120 10 Example 2 48 1.5 15 6.5 0.08 45 8 Example 3 33 10 9.5 10 0.06 90 2.5 Example 4 26 8 16 4 0.06 147 7 Example 5 40 5 8 12 0.08 75 5 Example 6 36 1.5 18 12 0.07 90 3 Example 7 20 10 25 3.9 0.08 45 9 Example 8 45 0.5 1.0 8 7.0 0.06 65 6 Example 9 22 5 5 5 3 8 4 0.08 147 10 Example 10 30 2.4 3.6 10 15 1.6 2.3 0.05 125 4 Comparative Example 1 5 0.5 9.5 10 0.06 90 2.5 Comparative Example 2 26 8 20 4 0.06 30 7 Comparative Example 3 40 5 8 12 0.01 75 1

[0021] Among them, the auxiliary agent in Example 1 is fatty alcohol polyoxyethylene ether, the auxiliary agent in Example 2 is alcohol ether phosphate, the auxiliary agent in Example 3 is sodium dodecyl sulfonate, the auxiliary agent in Example 4 is a mixture of fatty alcohol polyoxyethylene ether, alcohol ether phosphate and sodium dodecyl sulfonate, the auxiliary agent in Example 5 is a mixture of alcohol ether phosphate and sodium dodecyl sulfonate, and the auxiliary agents in Examples 6-10 are all fatty alcohol polyoxyethylene ether. The auxiliary agents in Comparative Examples 1-3 are all fatty alcohol polyoxyethylene ether.

[0022] The method of use is: when using the coloring agent for coloring, first spray or brush the pretreatment agent on the rusty weathering steel surface without dust, grease and other dirt, then spray or brush the coloring agent on the weathering steel surface that has not yet dried, and repeat the above steps after the weathering steel surface is completely dry until the rust layer presents a blue color. The implementation effect of the embodiment is shown in Table 2.

[0023] Table 2 Effects of Examples and Comparative Examples

[0024] <![CDATA[Weather-resistant steel plate color after treatment 1 > <![CDATA[Hiding power of weathering steel plate 2 > <![CDATA[Color uniformity 3 > Example 1 Sapphire Blue ○ √ Example 2 Cobalt Blue ○ √ Example 3 Cobalt Blue ○ √ Example 4 Sapphire Blue ○ √ Example 5 Cobalt Blue ○ √ Example 6 Cobalt Blue ○ √ Example 7 Cobalt Blue ○ √ Example 8 Cobalt Blue ○ √ Example 9 Sapphire Blue ○ √ Example 10 Sapphire Blue ○ √ Comparative Example 1 Chocolate Brown ╳ √ Comparative Example 2 Gray brown ╳ √ Comparative Example 3 Dark Blue ○ ╳

[0025] Note: 1. Color description is based on the RAL international color card.

[0026] 2. “○” means the substrate color is completely covered and has good hiding power, while “╳” means poor hiding power.

[0027] 3. “√” represents uniform color of the substrate, and “╳” represents uneven color.

[0028] The implementation effects of each embodiment show that the use of this treatment agent can make the rust layer surface appear sapphire blue or cobalt blue, thus presenting a decorative appearance. Compared with Examples 1 to 10, the content of citric acid and inorganic acid in Comparative Example 1 is too low, resulting in insufficient iron ions participating in the coloring chemical reaction on the surface of the weathering steel, and the coloring effect is not good. Compared with Examples 1 to 10, the content of ferrocyanide in Comparative Example 2 is too low, resulting in insufficient ferrocyanide participating in the coloring chemical reaction on the surface of the weathering steel, and the coloring effect is not good. Compared with Examples 1 to 10, the content of auxiliary agents and penetrants in Comparative Example 3 is too low, resulting in the inability of the pretreatment agent and colorant to fully and evenly infiltrate and react on the surface of the weathering steel, resulting in uneven color.

Claims

1. A blue coloring agent for weathering steel rust layer, characterized in that: The coloring agent is composed of a pretreatment agent and a coloring agent, wherein the pretreatment agent is composed of: citric acid: 19-48 g / L, inorganic acid: 1.5-10 g / L, copper salt: 8-25 g / L, nickel salt: 3.9-12 g / L, auxiliary agent: 0.05-0.08 g / L, and the balance is water; the coloring agent is composed of: ferrocyanide: 45-147 g / L, penetrant: 2.5-10 g / L, and the balance is water; The inorganic acid is one or both of hydrochloric acid and sulfuric acid; The copper salt is one or both of CuCl2 and CuSO4; The nickel salt is one or both of NiCl2 and NiSO4; The auxiliary agent is one or more of fatty alcohol polyoxyethylene ether, alcohol ether phosphate, and sodium dodecyl sulfate; The ferrocyanide is one of K4[Fe(CN)6] and Na4[Fe(CN)6]; The penetrant is sodium chloride; The method for using the blue coloring treatment agent for the rust layer of weathering steel is to first spray or brush the pretreatment agent on the rusty weathering steel surface without dirt, then spray or brush the coloring agent on the weathering steel surface that has not yet dried, and repeat the above steps after the weathering steel surface is completely dry until the rust layer presents a blue color.

2. A method for using the blue coloring agent for weathering steel rust layer according to claim 1, characterized in that: First, spray or brush the pretreatment agent on the rusty weathering steel surface without dirt, then spray or brush the colorant on the weathering steel surface that has not yet dried. After the weathering steel surface is completely dry, repeat the above steps until the rust layer appears blue.