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

Abstract

The present invention belongs to the field of corrosion science and relates to a steel plate surface treatment agent, specifically a green coloring treatment agent for weathering steel rust layer and a method of using the same, wherein the coloring treatment agent is composed of a pretreatment agent and a coloring agent, wherein the pretreatment agent is composed of: hydrochloric acid: 20-35 g / L, oxidant: 20.4-34 g / L, and the balance is water; the coloring agent is composed of: ferrocyanide: 31-65 g / L, auxiliary agent: 0.1-0.25 g / L, and the balance is water. Compared with the prior art, the beneficial effect of the present invention is that the surface of the weathering steel treated with the treatment agent is green and has a good decorative appearance, providing a solution for the color performance and application scenario expansion of the coating-free weathering steel. The green coloring treatment agent is water-based and does not contain harmful components such as volatile organic compounds 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 green coloring treatment agent for 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. Summary of the invention

[0004] The purpose of the present invention is to provide a green coloring treatment agent for the rust layer of weathering steel and a method of using the same in view of the shortcomings of the existing methods. The present invention is used for the surface of weathering steel that is naturally corroded or covered with a rust layer after rust layer 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 green and has a good decorative appearance.

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

[0006] A green coloring agent for weathering steel rust layer, characterized in that the coloring agent consists of a pretreatment agent and a coloring agent, the pretreatment agent is composed of: hydrochloric acid: 20-35 g / L, oxidant: 20.4-34 g / L, and the balance is water (total amount is 1 liter); the coloring agent is composed of: ferrocyanide: 31-65 g / L, auxiliary agent: 0.1-0.25 g / L, and the balance is water (total amount is 1 liter).

[0007] The function of hydrochloric acid is to quickly generate iron ions on the surface of weathering steel, while providing favorable acidic conditions for the chemical reaction of the coloring process.

[0008] The oxidant is H2O2, which is used to oxidize the ferrous ions generated on the surface of the weathering steel into ferric ions, thereby providing reactants for the chemical reaction in the coloring process.

[0009] The ferrocyanide is one of K3[Fe(CN)6] and Na3[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 dark green coordination compound. The coordination compound has the characteristics of being non-toxic and having good color stability.

[0010] The auxiliary agent is one or more of monolauryl phosphate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether. 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.

[0011] A method for using a green coloring agent for a rust layer of weathering steel. When the coloring agent is used for coloring, firstly spray or brush the pretreatment agent on the rusty weathering steel surface without dirt such as dust and grease, and then spray or brush the coloring agent on the weathering steel surface that has not yet dried. After the surface of the weathering steel is completely dry, repeat the above steps until the rust layer presents a green color.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The surface of weathering steel treated with this treatment agent is green and has a good decorative appearance, providing a solution for the color performance and application scenario expansion of unpainted weathering steel. The green 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

[0014] 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.

[0015] The embodiments and comparative examples of the present invention are shown in Table 1 (contents are all in g / L).

[0016] Table 1 Examples of the present invention and comparative examples

[0017] hydrochloric acid <![CDATA[Oxidant (H2O2)]]> <![CDATA[K3[Fe(CN)6]]]> <![CDATA[Na3[Fe(CN)6]]]> Monolauryl phosphate Fatty alcohol polyoxyethylene ether Alkylphenol polyoxyethylene ether Example 1 20 25 50 0.2 Example 2 35 34 65 0.25 Example 3 25 20.4 45 0.2 Example 4 30 28 31 0.03 0.07 0.05 Example 5 25 30 55 0.4 0.6 Example 6 22 26 65 0.07 0.15 Example 7 34 21 48 0.04 0.09 Example 8 28 25.5 31 0.08 0.08 0.08 Example 9 32 32 52 0.07 0.1 Example 10 24 27.3 40 0.14 0.05 Comparative Example 1 10 20.4 45 0.2 Comparative Example 2 30 10 31 0.15 Comparative Example 3 25 20.4 20 0.2 Comparative Example 4 30 28 31 0.01 0.01

[0018] The method of use is as follows: when using the coloring agent for coloring treatment, first spray or brush the pretreatment agent on the rusty weathering steel surface without dust, grease and other dirt, and then spray or brush the coloring agent on the weathering steel surface that has not yet dried. After the surface of the weathering steel is completely dry, repeat the above steps until the rust layer presents a green color. The implementation effects of the embodiments and comparative examples are shown in Table 2.

[0019] Table 2 Effects of Examples and Comparative Examples

[0020] <![CDATA[Weathering steel plate color after treatment 1 > <![CDATA[Hiding power of weathering steel plate 2 > <![CDATA[Color uniformity 3 > Example 1 Dark green ○ √ Example 2 Moss Green ○ √ Example 3 Blue-green ○ √ Example 4 Brown Green ○ √ Example 5 Moss Green ○ √ Example 6 Moss Green ○ √ Example 7 Blue-green ○ √ Example 8 Brown Green ○ √ Example 9 Moss Green ○ √ Example 10 Blue-green ○ √ Comparative Example 1 Dark brown ╳ √ Comparative Example 2 Cobalt Blue ○ √ Comparative Example 3 Blue and black ╳ √ Comparative Example 4 Dark green ○ ╳

[0021] Note: 1. Color description is based on the RAL international color card.

[0022] 2. “○” means the substrate color is completely covered and has good hiding power, while “╳” means poor hiding power.

[0023] 3. “√” represents uniform color of the substrate, and “╳” represents uneven color.

[0024] The implementation effects of each embodiment show that the use of this treatment agent can make the rust layer surface present various green colors such as dark green, moss green, blue-green, and brown-green, thereby presenting a decorative appearance. Compared with Examples 1 to 10, the hydrochloric acid content in Comparative Example 1 is too low, resulting in insufficient iron ions on the surface of the weathering steel participating in the coloring chemical reaction, and the coloring effect is not good. Compared with Examples 1 to 10, the oxidant content in Comparative Example 2 is too low, resulting in insufficient trivalent iron ions on the surface of the weathering steel participating in the coloring chemical reaction, and the coloring effect is not good. Compared with Examples 1 to 10, the ferrocyanide content in Comparative Example 3 is too low, resulting in insufficient ferrocyanide on the surface of the weathering steel participating in the coloring chemical reaction, and the coloring effect is not good. Compared with Examples 1 to 10, the auxiliary agent and penetrant content in Comparative Example 4 is too low, resulting in the pretreatment agent and colorant being unable to fully and evenly infiltrate and react on the surface of the weathering steel, resulting in uneven color.

Claims

1. A green 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: hydrochloric acid: 20-35 g / L, oxidant: 20.4-34 g / L, and the balance is water; the coloring agent is composed of: ferrocyanide: 31-65 g / L, auxiliary agent: 0.1-0.25 g / L, and the balance is water; The oxidant is H2O2; The ferrocyanide is one of K3[Fe(CN)6] and Na3[Fe(CN)6]; The auxiliary agent is one or more of monolauryl phosphate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether; The method of using the green coloring 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, and then spray or brush the coloring agent 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 green in color.

2. A method for using the green coloring agent for weathering steel rust layer as claimed in claim 1, characterized in that: First, spray or brush the pretreatment agent on the rusty weathering steel surface without dirt, and 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 green in color.