Surface treating agent and preparation method thereof

Abstract

The invention discloses a surface treating agent and a preparation method thereof. The surface treating agent is prepared from the following components in parts by weight: 8-12 parts of modified sodium silicate, 5-8 parts of potassium carbonate, 13-20 parts of a surfactant, 2.5-4 parts of a corrosion inhibitor, 0.5-1 part of nano silicon dioxide, 2-4 parts of sodium citrate, 0.3-0.8 part of polyether modified siloxane and 50-60 parts of deionized water. Polymetal salts are introduced to modify sodium silicate to obtain modified sodium silicate, so that the compactness of a formed film is improved, and the corrosion inhibition, the wear resistance and the environmental adaptability of the modified sodium silicate in the metal treatment agent can be remarkably improved. And meanwhile, modified sodium silicate, benzotriazole and sodium phytate cooperate to form a corrosion inhibition mechanism, and the metal surface corrosion rate is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of surface treatment agents, in particular to a surface treatment agent and a preparation method thereof. Background Art

[0002] Surface treatment agent refers to the reagent used to treat the surface of a material to achieve a specific purpose, including metal surface treatment agent.

[0003] Metal surface treatment agents are a general term for chemical agents used to treat metal surfaces. Metal surface treatment includes pre-treatment of substrates such as degreasing, rust removal, phosphating, and rust prevention, preparing for metal coating and metal protection technologies.

[0004] In order to facilitate the subsequent processing of metal workpieces, metal surface treatment agents are needed to clean the surface of metal workpieces, thereby removing mineral oils (such as cutting oils, rust-proof oils), animal and vegetable oils, polishing wax, etc. attached to the metal surface. This provides a clean and activated substrate surface for subsequent processes (such as phosphating, electroplating, and spraying).

[0005] However, existing alkaline metal surface treatment agents (alkaline degreasing agents) are prone to corroding the metal surface when cleaning it, causing the metal surface to turn black or produce pitting; therefore, the present application proposes a surface treatment agent and a preparation method thereof. Summary of the Invention

[0006] The object of the present invention is to provide a surface treatment agent and a preparation method thereof to solve the problems raised in the above background technology.

[0007] According to a first aspect of the present invention, there is provided a surface treatment agent comprising the following components in parts by weight: 8-12 parts of modified sodium silicate, 5-8 parts of potassium carbonate, 13-20 parts of surfactant, 2.5-4 parts of corrosion inhibitor, 0.5-1 part of nano-silica, 2-4 parts of sodium citrate, 0.3-0.8 parts of polyether-modified siloxane, and 50-60 parts of deionized water.

[0008] According to an embodiment of the present invention, the modification steps of the modified sodium silicate are: Step 1: Dissolve sodium silicate in 60°C deionized water and stir until transparent; Step 2: Sodium molybdate, cerium nitrate and zinc phosphate were added in sequence, and the temperature was raised to 80°C and kept constant for 2 hours; Step 3: Cool and filter to obtain modified sodium silicate.

[0009] According to an embodiment of the present invention, the weight proportions of sodium silicate, sodium molybdate, cerium nitrate, zinc phosphate and deionized water are respectively: 100-120 parts of sodium silicate, 10-15 parts of sodium molybdate, 3-5 parts of cerium nitrate, 5-8 parts of zinc phosphate and 200-220 parts of deionized water.

[0010] According to an embodiment of the present invention, the surfactant is composed of the following components in parts by weight: 10-15 parts of alkyl glycoside and 3-5 parts of sodium isomeric alcohol ether sulfate.

[0011] According to an embodiment of the present invention, the corrosion inhibitor is composed of the following components in parts by weight: 0.5-1 parts of benzotriazole and 2-3 parts of sodium phytate.

[0012] According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned surface treatment agent, comprising the following steps: Step 1: Add 40% deionized water to the main reactor, then heat it to 45-50°C, then slowly add nano-silica, and disperse it at a high shear speed of 2000 rpm for 30 minutes to form a stable suspension; Step 2: Cool to 35°C, add modified sodium silicate and potassium carbonate in sequence, stir to dissolve, then add sodium citrate, and continue stirring until completely transparent; Step 3: Add the remaining deionized water to the secondary reactor, then add the alkyl glycoside and isomeric alcohol ether sodium sulfate in sequence, heat to 40°C to form a homogeneous liquid to obtain a mixed surfactant solution, and then add the surfactant solution to the main reactor; Step 4: Pre-dissolve benzotriazole in ethanol and then add it to the main reactor, followed by sodium phytate, and stir until completely dissolved; Step 5: Then add polyether-modified siloxane; adjust the pH to 10.5 with 10% citric acid; and then remove impurities through a plate-and-frame filter to obtain the surface treatment agent.

[0013] According to an embodiment of the present invention, in step 2, the stirring and dissolving conditions after adding the modified sodium silicate and potassium carbonate are: a stirring speed of 500 rpm and a stirring time of 20 minutes.

[0014] According to an embodiment of the present invention, in step three, the surfactant solution is added to the main reactor at a feeding rate of less than 5 L / min.

[0015] According to an embodiment of the present invention, in step 4, the mass ratio of benzotriazole to ethanol is 1:5.

[0016] According to an embodiment of the present invention, in step five, the filter pore size of the plate and frame filter is 5 μm.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The modified sodium silicate obtained by introducing polymetallic salts into the modified sodium silicate improves film density and significantly enhances the corrosion inhibition, wear resistance, and environmental adaptability of the modified sodium silicate in metal treatment agents. Furthermore, the modified sodium silicate, benzotriazole, and sodium phytate synergistically form a corrosion inhibition mechanism, reducing the corrosion rate of metal surfaces. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] According to a first aspect of the present invention, there is provided a surface treatment agent comprising the following components in parts by weight: 8-12 parts of modified sodium silicate, 5-8 parts of potassium carbonate, 13-20 parts of surfactant, 2.5-4 parts of corrosion inhibitor, 0.5-1 part of nano-silica, 2-4 parts of sodium citrate, 0.3-0.8 parts of polyether-modified siloxane, and 50-60 parts of deionized water.

[0020] According to an embodiment of the present invention, the modification steps of modified sodium silicate are: Step 1: Dissolve sodium silicate in 60°C deionized water and stir until transparent; Step 2: Sodium molybdate, cerium nitrate and zinc phosphate were added in sequence, and the temperature was raised to 80°C and kept constant for 2 hours; Step 3: Cool and filter to obtain modified sodium silicate.

[0021] According to an embodiment of the present invention, the weight proportions of sodium silicate, sodium molybdate, cerium nitrate, zinc phosphate and deionized water are respectively: 100-120 parts of sodium silicate, 10-15 parts of sodium molybdate, 3-5 parts of cerium nitrate, 5-8 parts of zinc phosphate and 200-220 parts of deionized water.

[0022] Sodium silicate is easily penetrated by corrosive media in metal surface treatment agents, leading to local corrosion. Therefore, the present invention modifies sodium silicate by introducing polymetallic salts to modify the sodium silicate to obtain modified sodium silicate, thereby improving the density of the film and significantly improving the corrosion inhibition, wear resistance and environmental adaptability of the modified sodium silicate in the metal treatment agent.

[0023] Among them, potassium carbonate can adjust pH and enhance electrolyte activity.

[0024] According to an embodiment of the present invention, the surfactant is composed of the following components in parts by weight: 10-15 parts of alkyl glycoside and 3-5 parts of sodium isomeric alcohol ether sulfate.

[0025] Alkyl polyglycoside is a nonionic surfactant and sodium isomeric alcohol ether sulfate is an anionic surfactant. The use of a high-efficiency combination of nonionic and anionic surfactants enhances detergency and reduces alkalinity requirements.

[0026] According to an embodiment of the present invention, the corrosion inhibitor is composed of the following components in parts by weight: 0.5-1 parts of benzotriazole and 2-3 parts of sodium phytate.

[0027] Modified sodium silicate, benzotriazole and sodium phytate synergistically form a corrosion inhibition mechanism to reduce the corrosion rate of the metal surface.

[0028] Among them, the particle size of nano-silica is 10nm. Nano-silica can absorb oil stains and enhance the roughness of the metal workpiece surface (promoting subsequent coating).

[0029] Among them, sodium citrate can soften hard water and prevent silicate precipitation; polyether-modified siloxane can defoam and reduce surface tension; deionized water serves as a solvent carrier.

[0030] According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned surface treatment agent, comprising the following steps: Step 1: Add 40% deionized water to the main reactor, then heat it to 45-50°C, then slowly add nano-silica, and disperse it at a high shear speed of 2000 rpm for 30 minutes to form a stable suspension; Step 2: Cool to 35°C, add modified sodium silicate and potassium carbonate in sequence, stir to dissolve, stirring at 500 rpm for 20 minutes, then add sodium citrate, and continue stirring until completely transparent; Step 3: Add the remaining deionized water to the secondary reactor, then add alkyl glycoside and isomeric alcohol ether sodium sulfate in sequence, heat to 40°C to form a homogeneous liquid to obtain a mixed surfactant solution, and then add the surfactant solution to the main reactor at a feeding rate of <5L / min; Step 4: Pre-dissolve benzotriazole in ethanol at a mass ratio of benzotriazole to ethanol of 1:5, then add the solution to the main reactor, followed by sodium phytate, and stir until completely dissolved; Step 5: Then add polyether-modified siloxane; and adjust the pH to 10.5 with 10% citric acid; then remove impurities through a plate and frame filter with a filtration pore size of 5 μm to obtain the surface treatment agent.

[0031] Example 1: A surface treatment agent, comprising the following components in parts by weight: 8 parts of modified sodium silicate, 6 parts of potassium carbonate, 12 parts of alkyl glycoside, 4 parts of isomeric alcohol ether sodium sulfate, 0.5 parts of benzotriazole, 2 parts of sodium phytate, 0.8 parts of nano-silica, 3 parts of sodium citrate, 0.5 parts of polyether modified siloxane, and 50 parts of deionized water.

[0032] Example 2: A surface treatment agent, comprising the following components in parts by weight: 12 parts of modified sodium silicate, 6 parts of potassium carbonate, 12 parts of alkyl glycoside, 4 parts of isomeric alcohol ether sodium sulfate, 0.5 parts of benzotriazole, 2 parts of sodium phytate, 0.8 parts of nano-silica, 3 parts of sodium citrate, 0.5 parts of polyether modified siloxane, and 50 parts of deionized water.

[0033] Example 3: A surface treatment agent, comprising the following components in parts by weight: 8 parts of modified sodium silicate, 6 parts of potassium carbonate, 12 parts of alkyl glycoside, 4 parts of isomeric alcohol ether sodium sulfate, 0.5 parts of benzotriazole, 2 parts of sodium phytate, 0.8 parts of nano-silica, 3 parts of sodium citrate, 0.5 parts of polyether modified siloxane, and 60 parts of deionized water.

[0034] Comparative Example 1: A surface treatment agent, comprising the following components in parts by weight: 8 parts of sodium silicate, 6 parts of potassium carbonate, 12 parts of alkyl glycoside, 4 parts of isomeric alcohol ether sodium sulfate, 0.5 parts of benzotriazole, 2 parts of sodium phytate, 0.8 parts of nano silicon dioxide, 3 parts of sodium citrate, 0.5 parts of polyether modified siloxane, and 50 parts of deionized water.

[0035] The difference between Comparative Example 1 and Example 1 is that ordinary sodium silicate is used instead of modified sodium silicate, and the other components are the same.

[0036] Comparative Example 2: A surface treatment agent, comprising the following components in parts by weight: 6 parts of potassium carbonate, 12 parts of alkyl glycoside, 4 parts of isomeric alcohol ether sodium sulfate, 0.5 parts of benzotriazole, 2 parts of sodium phytate, 0.8 parts of nano silicon dioxide, 3 parts of sodium citrate, 0.5 parts of polyether modified siloxane, and 50 parts of deionized water.

[0037] The difference between Comparative Example 2 and Example 1 is the lack of modified sodium silicate, and the other components are the same.

[0038] Comparative Example 3: A surface treatment agent, comprising the following components in parts by weight: 8 parts of modified sodium silicate, 6 parts of potassium carbonate, 12 parts of alkyl glycoside, 4 parts of sodium isomeric alcohol ether sulfate, 0.8 parts of nano-silica, 3 parts of sodium citrate, 0.5 parts of polyether-modified siloxane, and 50 parts of deionized water.

[0039] The difference between Comparative Example 3 and Example 1 is that 0.5 parts of benzotriazole and 2 parts of sodium phytate are missing, and the other components are the same.

[0040] Experimental Example 1: Degreasing and cleaning efficiency test. The degreasing rate test complies with GB / T 35759-2017 "Determination of detergency of metal cleaning agents"; The surface treatment agents obtained in Examples 1-3 and Comparative Examples 1-3 were tested; The test method is as follows: Pretreatment: First, take 6 aluminum metal plates (size 100mm×50mm×2mm) with a surface roughness of Ra=0.8μm, and then apply oil to all aluminum metal plates: ISO 12137-1 standard mineral oil (coating amount 1.5±0.2g / m²); Then all aluminum metal plates were ultrasonically cleaned with acetone for 10 min → rinsed with deionized water → dried (50 °C × 30 min).

[0041] Weighing (W0), weighing after coating with mineral oil (W1) Cleaning treatment: 6 aluminum metal plates were immersed in the surface treatment agents (concentration 10%, temperature 45°C) obtained in Examples 1-3 and Comparative Examples 1-3, respectively, and ultrasonically cleaned for 5 minutes; Then rinse with deionized water → dry (50℃×30min) → weigh (W2).

[0042] Oil removal rate (%) = ; The test results are shown in Table 1 below; Table 1 Oil removal rate Group <![CDATA[W0(g)]]> <![CDATA[W1(g)]]> <![CDATA[W2(g)]]> Oil removal rate (%) Example 1 50.145 50.331 50.153 95.7 Example 2 50.148 50.336 50.157 95.2 Example 3 50.144 50.352 50.153 95.7 Comparative Example 1 50.146 50.346 50.186 80.0 Comparative Example 2 50.145 50.338 50.195 74.1 Comparative Example 3 50.147 50.341 50.197 74.2 As can be seen from the table above, after the aluminum metal plate is treated with the surface treatment agent prepared in this application, the degreasing rate is significantly higher than that of Comparative Examples 1 to 3. Therefore, the surface treatment agent prepared in this application has good metal surface degreasing ability.

[0043] Experimental Example 2: Corrosion inhibition ability test; salt spray test was used in accordance with ASTM B117-19 "Salt Spray Test Standard" The surface treatment agents obtained in Examples 1-3 and Comparative Examples 1-3 were tested; The test method is as follows: Pretreatment: First, take 6 aluminum metal plates (size 100 mm × 50 mm × 2 mm) with a surface roughness of Ra = 0.8 μm, and then all aluminum metal plates are ultrasonically cleaned with acetone for 10 min → rinsed with deionized water → dried (50℃ × 30 min).

[0044] Cleaning treatment: Six aluminum metal plates were immersed in the surface treatment agents (concentration 10%, temperature 35°C) obtained in Examples 1-3 and Comparative Examples 1-3, respectively, and ultrasonically cleaned for 10 minutes; then dried (80°C × 20 minutes) → weighed (W2).

[0045] Test conditions: Salt solution: 5% NaCl, pH=6.5-7.2, temperature 35℃, continuous spraying.

[0046] Observation records: Record the number and area of ​​surface corrosion points every 24 hours.

[0047] The corrosion conditions of the sample surface were recorded as shown in Table 2 below.

[0048] Table 2 Surface corrosion of aluminum metal plates Group Surface corrosion of aluminum metal plates Example 1 Basically no change Example 2 Basically no change Example 3 Basically no change Comparative Example 1 Some rust on the edges, intact in the middle Comparative Example 2 Rust marks on the edges and a small amount of rust in the middle Comparative Example 3 Rust marks on the edges and a small amount of rust in the middle As can be seen from the above table, by comparing Example 1 with Comparative Example 1, it can be seen that after sodium silicate replaces modified sodium silicate, the corrosion inhibition ability is reduced; by comparing Example 1 with Comparative Example 2, it can be seen that after the modified sodium silicate is removed, the corrosion inhibition ability is significantly reduced; by comparing Example 1 with Comparative Example 3, it can be seen that after benzotriazole and sodium phytate are removed, the corrosion inhibition ability is significantly reduced; therefore, the present application uses modified sodium silicate, benzotriazole and sodium phytate to synergistically form a corrosion inhibition mechanism to reduce the corrosion rate of the metal surface.

[0049] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A surface treatment agent, characterized in that It is composed of the following components in parts by weight: 8-12 parts of modified sodium silicate, 5-8 parts of potassium carbonate, 13-20 parts of surfactant, 2.5-4 parts of corrosion inhibitor, 0.5-1 part of nano-silica, 2-4 parts of sodium citrate, 0.3-0.8 parts of polyether-modified siloxane, and 50-60 parts of deionized water.

2. A surface treatment agent according to claim 1, characterized in that: The modification steps of the modified sodium silicate are: Step 1: Dissolve sodium silicate in 60°C deionized water and stir until transparent; Step 2: Sodium molybdate, cerium nitrate and zinc phosphate were added in sequence, and the temperature was raised to 80°C and kept constant for 2 hours; Step 3: Cool and filter to obtain modified sodium silicate.

3. A surface treatment agent according to claim 2, characterized in that: The weight proportions of sodium silicate, sodium molybdate, cerium nitrate, zinc phosphate and deionized water are respectively: 100-120 parts of sodium silicate, 10-15 parts of sodium molybdate, 3-5 parts of cerium nitrate, 5-8 parts of zinc phosphate and 200-220 parts of deionized water.

4. A surface treatment agent according to claim 3, characterized in that: The surfactant is composed of the following components in parts by weight: 10-15 parts of alkyl glycoside and 3-5 parts of isomeric alcohol ether sodium sulfate.

5. A surface treatment agent according to claim 4, characterized in that: The corrosion inhibitor is composed of the following components in parts by weight: 0.5-1 parts of benzotriazole and 2-3 parts of sodium phytate.

6. A method for preparing a surface treatment agent according to claim 5, characterized in that: The following steps are involved: Step 1: Add 40% deionized water to the main reactor, then heat it to 45-50°C, then slowly add nano-silica, and disperse it at a high shear speed of 2000 rpm for 30 minutes to form a stable suspension; Step 2: Cool to 35°C, add modified sodium silicate and potassium carbonate in sequence, stir to dissolve, then add sodium citrate, and continue stirring until completely transparent; Step 3: Add the remaining deionized water to the secondary reactor, then add the alkyl glycoside and isomeric alcohol ether sodium sulfate in sequence, heat to 40°C to form a homogeneous liquid to obtain a mixed surfactant solution, and then add the surfactant solution to the main reactor; Step 4: Pre-dissolve benzotriazole in ethanol and then add it to the main reactor, followed by sodium phytate, and stir until completely dissolved; Step 5: Then add polyether-modified siloxane; adjust the pH to 10.5 with 10% citric acid; and then remove impurities through a plate-and-frame filter to obtain the surface treatment agent.

7. The method for preparing a surface treatment agent according to claim 6, wherein: In step 2, the stirring and dissolving conditions after adding the modified sodium silicate and potassium carbonate are: stirring speed of 500 rpm, stirring time of 20 minutes.

8. The method for preparing a surface treatment agent according to claim 6, wherein: In step 3, the surfactant solution is added to the main reactor at a feeding rate of less than 5 L / min.

9. The method for preparing a surface treatment agent according to claim 6, wherein: In step 4, the mass ratio of benzotriazole to ethanol is 1:

5.

10. The method for preparing a surface treatment agent according to claim 6, characterized in that: In step five, the filter pore size of the plate and frame filter is 5 μm.