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

Abstract

The present invention relates to a white coloring agent for weathering steel rust layer and a method for using the same. The coloring agent is composed of an agent A and an agent B. The agent A is composed of ferrocyanide: 4.5-18.4 g / L, penetrant: 70-290 g / L, thickener: 5-10 g / L, and the balance is water; the agent B is composed of manganese salt: 3.8-7.6 g / L, auxiliary agent: 0.05-0.1 g / L, and the balance is water. Compared with the prior art, the present invention has the following beneficial effects: the surface of the weathering steel treated with the treatment agent is white and has a good decorative appearance, providing a solution for the color performance and application scenario expansion of the coating-free weathering steel. The white coloring 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 white 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 contains hexavalent chromium and is prone to produce irritating acid mist after heating, which limits the applicability of construction. Summary of the invention

[0004] The purpose of the present invention is to address the shortcomings of the existing methods and provide a white 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 white and has a good decorative appearance.

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

[0006] A white coloring agent for weathering steel rust layer, the coloring agent consists of agent A and agent B, the agent A consists of: 4.5-18.4 g / L ferrocyanide, 70-290 g / L penetrant, 5-10 g / L thickener, and the balance is water (total amount is 1 liter); the agent B consists of: 3.8-7.6 g / L manganese salt, 0.05-0.1 g / L auxiliary agent, and the balance is water (total amount is 1 liter).

[0007] The ferrocyanide is one of K4[Fe(CN)6] and Na4[Fe(CN)6], and is the main component of agent A, which can react with manganese ions to form a white coordination compound. The coordination compound has the characteristics of being non-toxic and having good color stability.

[0008] The penetrant is one or both of NaCl and KCl, and its function is to improve the permeability of agent A in the rust layer of weathering steel, so that agent A can fully penetrate into the microstructure of the rust layer and improve the coloring effect.

[0009] The thickener is hydroxyethyl cellulose, and the molar substitution degree of the hydroxyethyl cellulose is 1.3 to 2.5. The function of the hydroxyethyl cellulose is to keep the A agent at a proper viscosity and to enhance the coverage of the coloring reaction product on the surface of the weathering steel plate.

[0010] The manganese salt is one or both of MnSO4 and MnCl2, and the manganese ions thereof can react with the ferrocyanide in the A agent to generate a white coordination compound.

[0011] The auxiliary agent is sodium dodecyl sulfate. The rust layer on the surface of weathering steel has a rough and loose structure at the microscopic level. The function of the auxiliary agent is to improve the wettability of agent B on the surface of weathering steel, so that it can fully react with agent A on the surface of weathering steel.

[0012] A method for using a white coloring agent for a rust layer of weathering steel. When using the coloring agent for coloring, first spray or brush agent A on the surface of the rusty weathering steel without dirt such as dust and grease, then spray or brush agent B on the surface of the weathering steel that has not yet dried, and repeat the above steps after the surface of the weathering steel is completely dry until the rust layer appears white.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The surface of weathering steel treated with this treatment agent appears white and has a good decorative appearance, providing a solution for the color performance and application scenario expansion of unpainted weathering steel. The white coloring treatment agent is water-based and does not contain harmful ingredients 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. DETAILED DESCRIPTION

[0015] 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.

[0016] The embodiments and comparative examples of the present invention are shown in Table 1 (contents are all in g / L).

[0017] Table 1 Examples of the present invention and comparative examples

[0018] <![CDATA[K4[Fe(CN)6]]]> <![CDATA[Na4[Fe(CN)6]]]> KCl NaCl Hydroxyethyl Cellulose <![CDATA[MnSO4]]> <![CDATA[MnCl2]]> Sodium Lauryl Sulfate Example 1 4.5 200 8 3.8 0.05 Example 2 18.4 290 5 7.6 0.06 Example 3 12.5 70 6 6.5 0.08 Example 4 15.0 150 10 5.5 0.06 Example 5 6.8 150 7 6.5 0.1 Example 6 18.4 180 9 6.0 0.08 Example 7 4.5 70 10 7.0 0.07 Example 8 8.5 100 190 5 4.5 0.05 Example 9 17.0 40 30 7 1.5 2.4 0.1 Example 10 10.0 90 90 8 4.1 2.5 0.08 Comparative Example 1 2.5 150 10 5.5 0.06 Comparative Example 2 8.5 20 8 3.8 0.01 Comparative Example 3 6.8 150 7 2.5 0.1 Comparative Example 4 12.5 70 2 6.5 0.08

[0019] The molar substitution degree of hydroxyethyl cellulose used in Example 1 is 2.0. The molar substitution degree of hydroxyethyl cellulose used in Example 2 is 2.2. The molar substitution degree of hydroxyethyl cellulose used in Example 3 is 1.5. The molar substitution degree of hydroxyethyl cellulose used in Example 4 is 1.8. The molar substitution degree of hydroxyethyl cellulose used in Example 5 is 2.3. The molar substitution degree of hydroxyethyl cellulose used in Example 6 is 1.4. The molar substitution degree of hydroxyethyl cellulose used in Example 7 is 2.0. The molar substitution degree of hydroxyethyl cellulose used in Example 8 is 2.1. The molar substitution degree of hydroxyethyl cellulose used in Example 9 is 2.5. The molar substitution degree of hydroxyethyl cellulose used in Example 10 is 1.9. The molar substitution degrees of hydroxyethyl cellulose in Comparative Examples 1-4 are all 2.5.

[0020] The method of use is: first spray or brush Agent A on the rusty weathering steel surface without dirt, then spray or brush Agent B 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 white color. The implementation effects of the embodiments and comparative examples of the present invention are shown in Table 2.

[0021] Table 2 Effects of Examples and Comparative Examples

[0022] <![CDATA[Weathering steel plate color after treatment 1 > <![CDATA[Hiding power of weathering steel plate 2 > <![CDATA[Color uniformity 3 > Example 1 Off-white ○ √ Example 2 Papyrus White ○ √ Example 3 Off-white ○ √ Example 4 signal white ○ √ Example 5 signal white ○ √ Example 6 Papyrus White ○ √ Example 7 Off-white ○ √ Example 8 signal white ○ √ Example 9 Papyrus White ○ √ Example 10 Off-white ○ √ Comparative Example 1 Light brown ╳ √ Comparative Example 2 Colorful yellow ○ ╳ Comparative Example 3 Orange brown ╳ √ Comparative Example 4 Colorful yellow ○ ╳

[0023] Note: 1. Color description is based on the RAL international color card.

[0024] 2. “○” means the substrate color is completely covered and has good hiding power, while “╳” means poor hiding power.

[0025] 3. “√” represents uniform color of the substrate, and “╳” represents uneven color.

[0026] The implementation effects of each embodiment show that the use of this treatment agent can make the rust layer surface appear white, such as grayish white, straw paper white, signal white, etc., thus presenting a decorative appearance. Compared with Examples 1 to 10, the content of ferrocyanide in Comparative Example 1 is too low, resulting in insufficient reactants participating in the coloring chemical reaction on the surface of the weathering steel, and poor coloring effect and hiding power. Compared with Examples 1 to 10, the content of penetrant in Comparative Example 2 is too low, so that the permeability and distribution uniformity of Agent A on the surface of weathering steel are poor, resulting in poor color uniformity. Compared with Examples 1 to 10, the content of manganese salt in Comparative Example 3 is too low, resulting in insufficient reactants participating in the coloring chemical reaction on the surface of weathering steel, and poor coloring effect. Compared with Examples 1 to 10, the content of thickener in Comparative Example 4 is too low, resulting in uneven distribution of the reaction products of Agent A and Agent B on the surface of weathering steel coloring chemical reaction, resulting in uneven color.

Claims

1. A white coloring agent for weathering steel rust layer, characterized in that: The coloring treatment agent is composed of agent A and agent B, wherein agent A is composed of: ferrocyanide: 4.5-18.4 g / L, penetrant: 70-290 g / L, thickener: 5-10 g / L, and the balance is water; and agent B is composed of: manganese salt: 3.8-7.6 g / L, auxiliary agent: 0.05-0.1 g / L, and the balance is water.

2. A white coloring agent for weathering steel rust layer according to claim 1, characterized in that: The ferrocyanide is one of K4[Fe(CN)6] and Na4[Fe(CN)6].

3. A white coloring agent for weathering steel rust layer according to claim 1, characterized in that: The penetrant is one or both of NaCl and KCl.

4. A white coloring agent for weathering steel rust layer according to claim 1, characterized in that: The thickener is hydroxyethyl cellulose, and the molar substitution degree of the hydroxyethyl cellulose is 1.3-2.

5.

5. A white coloring agent for weathering steel rust layer according to claim 1, characterized in that: The manganese salt is one or both of MnSO4 and MnCl2.

6. A white coloring agent for weathering steel rust layer according to claim 1, characterized in that: The auxiliary agent is sodium lauryl sulfate.

7. A method for using the white coloring agent for weathering steel rust layer according to any one of claims 1 to 6, characterized in that: First, spray or brush Agent A on the rusty weathering steel surface without dirt, then spray or brush Agent B on the weathering steel surface that has not yet dried. Repeat the above steps after the weathering steel surface is completely dry until the rust layer appears white.