A vertical electrostatic powder spraying alkaline pretreatment process

Abstract

The present invention provides a vertical electrostatic powder spraying alkaline pretreatment process, which relates to the field of electrostatic spraying technology. The vertical electrostatic powder spraying alkaline pretreatment process, the alkaline pretreatment comprises the following steps: Step 1: Pre-degreasing: cleaning the surface of the aluminum substrate, removing dust and impurities on the surface of the aluminum substrate, and destroying the natural oxide film; Step 2: Degreasing: further removing oil stains and oxide film on the surface of the aluminum substrate, and corroding the surface of the aluminum substrate to accelerate the speed of passivation film formation; Step 3: Cleaning: performing preliminary cleaning and fine cleaning on the surface of the aluminum substrate respectively. By adding a promoter, the use of sodium hydroxide and potassium hydroxide can be effectively reduced, and at the same time, a good etching and cleaning effect can be achieved, which is beneficial to reducing raw material costs and solving the problem of insufficient cleaning of the aluminum substrate surface, thereby ensuring the subsequent powder spraying quality.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic spraying, in particular to a vertical electrostatic powder spraying alkaline pretreatment process. Background Art

[0002] With the continuous development of society, the continuous advancement of industry technology, and the continuous strengthening of people's awareness of environmental protection, compared with the traditional electrostatic powder spraying substrate surface chromium acid pretreatment, in addition to the chromium-free passivation process that has been rolled out in the industry, the use of alkaline cleaning solution to replace the traditional acidic (fluoride-containing) cleaning solution for substrate surface pretreatment before chromium-free passivation has gradually become an industry development trend. Its main advantage is that it greatly reduces the harm to the environment caused by the use of acidic tank solution.

[0003] However, when cleaning the surface of the substrate, the alkaline pretreatment process currently exhibits a slower reaction speed than the acidic pretreatment process. When the chain speed reaches a certain speed, it is often easy to cause insufficient cleaning of the substrate surface, which in turn makes it difficult to form a passivation film, thus affecting the quality of subsequent powder spraying and easily causing powder loss quality problems. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the shortcomings of the existing technology, the present invention provides a vertical electrostatic powder spraying alkaline pretreatment process, which solves the problem that the alkaline pretreatment process has a slower reaction speed than the acidic pretreatment process. When the chain speed reaches a certain speed, it is often easy to cause insufficient cleaning of the substrate surface, which makes it difficult to form a passivation film, thereby affecting the subsequent powder spraying quality and easily causing powder falling quality problems.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a vertical electrostatic powder spraying alkaline pretreatment process, the alkaline pretreatment comprising the following steps:

[0008] Step 1: Pre-degreasing: Clean the surface of the aluminum substrate to remove dust and impurities on the surface of the aluminum substrate and destroy the natural oxide film;

[0009] Step 2: Degreasing: further remove the oil and oxide film on the surface of the aluminum substrate, and corrode the surface of the aluminum substrate to accelerate the formation of the passivation film;

[0010] Step 3: Cleaning: Perform preliminary cleaning and fine cleaning on the surface of the aluminum substrate twice;

[0011] Step 4: Pure water washing: After washing twice in step 3, the surface of the aluminum substrate is further cleaned to ensure that the surface of the aluminum profile is in a pure state;

[0012] Step 5: Chromium-free passivation: After the treatment in steps 3 and 4, the surface of the aluminum substrate is passivated to form a colorless chemical conversion film.

[0013] Preferably, in step 1 and step 2, an alkaline degreasing agent is required to degrease the surface of the aluminum substrate, and the alkaline degreasing agent includes the following components in parts by mass: 12-24 parts of scale inhibitor, 10-18 parts of dust suppressant, 16-34 parts of sodium olefin sulfonate, 6-15 parts of DMP-30, 10-16 parts of sodium hydroxide, 6-14 parts of potassium hydroxide and 25-35 parts of deionized water.

[0014] Preferably, the preparation method of the alkaline degreasing agent comprises the following steps:

[0015] Step 1: Mix and stir the scale inhibitor and the dust suppressant to obtain component A, and store component A for later use;

[0016] Step 2: Mixing sodium olefin sulfonate and DMP-30 to obtain component B, and heating component B and then keeping it warm;

[0017] Step 3: Mixing and stirring sodium hydroxide and potassium hydroxide to obtain component C, and storing component C for later use;

[0018] Step 4: Mix component A, component B and component C, and add deionized water to dilute them to obtain an alkaline degreasing agent.

[0019] Preferably, the etching amount of the aluminum substrate in step 2 needs to reach 0.8g / m 2 .

[0020] Preferably, the conductivity of the cleaning water in step 3 needs to be controlled within the range of 0-500 μs / cm.

[0021] Preferably, the pH value of the pure water used for cleaning in step 4 is controlled to be less than 8, and the conductivity of the pure water is controlled to be 0-100 us / cm.

[0022] Preferably, the conversion film in step 5 is 1-8 mg / m2 in terms of zirconium ions. 2 .

[0023] (3) Beneficial effects

[0024] The present invention provides a vertical electrostatic powder spraying alkaline pretreatment process, which has the following beneficial effects:

[0025] 1. By adding accelerators, the use of sodium hydroxide and potassium hydroxide can be effectively reduced, and a good etching and cleaning effect can be achieved, which is beneficial to reduce raw material costs and solve the problem of insufficient cleaning of the aluminum substrate surface, thereby ensuring the subsequent powder spraying quality.

[0026] 2. By adding scale inhibitors and dust suppressants, dust can be effectively prevented from falling onto the surface of the treated aluminum substrate, thereby affecting the quality of aluminum substrate treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a comparative statistical chart of the vertical electrostatic powder spraying alkaline pretreatment process proposed by the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] Example 1:

[0030] The embodiment of the present invention provides a vertical electrostatic powder spraying alkaline pretreatment process, the alkaline pretreatment comprising the following steps:

[0031] Step 1: Pre-degreasing: Clean the surface of the aluminum substrate to remove dust and impurities on the surface of the aluminum substrate and destroy the natural oxide film;

[0032] Step 2: Degreasing: further remove the oil and oxide film on the surface of the aluminum substrate, and corrode the surface of the aluminum substrate to accelerate the formation of the passivation film;

[0033] Step 3: Cleaning: Perform preliminary cleaning and fine cleaning on the surface of the aluminum substrate twice;

[0034] Step 4: Pure water washing: After washing twice in step 3, the surface of the aluminum substrate is further cleaned to ensure that the surface of the aluminum profile is in a pure state;

[0035] Step 5: Chromium-free passivation: After the treatment in steps 3 and 4, the surface of the aluminum substrate is passivated to form a colorless chemical conversion film.

[0036] In steps one and two, an alkaline degreasing agent is required to degrease the surface of the aluminum substrate. The alkaline degreasing agent includes the following components in parts by mass: 24 parts of scale inhibitor, 18 parts of dust suppressant, 34 parts of sodium olefin sulfonate, 15 parts of DMP-30, 16 parts of sodium hydroxide, 14 parts of potassium hydroxide and 35 parts of deionized water.

[0037] The preparation method of the alkaline degreasing agent comprises the following steps:

[0038] Step 1: Mix and stir the scale inhibitor and the dust suppressant to obtain component A, and store component A for later use;

[0039] Step 2: Mixing sodium olefin sulfonate and DMP-30 to obtain component B, and heating component B and then keeping it warm;

[0040] Step 3: Mixing and stirring sodium hydroxide and potassium hydroxide to obtain component C, and storing component C for later use;

[0041] Step 4: Mix component A, component B and component C, and add deionized water to dilute them to obtain an alkaline degreasing agent.

[0042] The etching amount of the aluminum substrate in step 2 needs to reach 1.2g / m 2 .

[0043] The conductivity of the cleaning water in step 3 needs to be controlled at 450µs / cm.

[0044] In step 4, the pH value of the pure water used for cleaning is controlled at 7, and the conductivity of the pure water is controlled at 92 us / cm.

[0045] The conversion coating in step 5 is calculated as 7 mg / m 2 .

[0046] Example 2:

[0047] The embodiment of the present invention provides a vertical electrostatic powder spraying alkaline pretreatment process, the alkaline pretreatment comprising the following steps:

[0048] Step 1: Pre-degreasing: Clean the surface of the aluminum substrate to remove dust and impurities on the surface of the aluminum substrate and destroy the natural oxide film;

[0049] Step 2: Degreasing: further remove the oil and oxide film on the surface of the aluminum substrate, and corrode the surface of the aluminum substrate to accelerate the formation of the passivation film;

[0050] Step 3: Cleaning: Perform preliminary cleaning and fine cleaning on the surface of the aluminum substrate twice;

[0051] Step 4: Pure water washing: After washing twice in step 3, the surface of the aluminum substrate is further cleaned to ensure that the surface of the aluminum profile is in a pure state;

[0052] Step 5: Chromium-free passivation: After the treatment in steps 3 and 4, the surface of the aluminum substrate is passivated to form a colorless chemical conversion film.

[0053] In steps 1 and 2, an alkaline degreasing agent is required to degrease the surface of the aluminum substrate. The alkaline degreasing agent includes the following components in parts by mass: 24 parts of scale inhibitor, 18 parts of dust suppressant, 34 parts of sodium olefin sulfonate, 16 parts of sodium hydroxide, 14 parts of potassium hydroxide and 35 parts of deionized water.

[0054] The preparation method of the alkaline degreasing agent comprises the following steps:

[0055] Step 1: Mix and stir the scale inhibitor and the dust suppressant to obtain component A, and store component A for later use;

[0056] Step 2: Mixing sodium olefin sulfonate, sodium hydroxide, and potassium hydroxide to obtain component B, and heating component B and then keeping it warm;

[0057] Step 3: Mix component A and component B, and add deionized water to dilute to obtain an alkaline degreasing agent.

[0058] The etching amount of the aluminum substrate in step 2 needs to reach 0.6g / m 2 .

[0059] The conductivity of the cleaning water in step 3 needs to be controlled at 450µs / cm.

[0060] In step 4, the pH value of the pure water used for cleaning is controlled at <8, and the conductivity of the pure water is controlled at 92 us / cm.

[0061] The conversion coating in step 5 is calculated as 7 mg / m 2 .

[0062] Example 3:

[0063] The embodiment of the present invention provides a vertical electrostatic powder spraying alkaline pretreatment process, the alkaline pretreatment comprising the following steps:

[0064] Step 1: Pre-degreasing: Clean the surface of the aluminum substrate to remove dust and impurities on the surface of the aluminum substrate and destroy the natural oxide film;

[0065] Step 2: Degreasing: further remove the oil and oxide film on the surface of the aluminum substrate, and corrode the surface of the aluminum substrate to accelerate the formation of the passivation film;

[0066] Step 3: Cleaning: Perform preliminary cleaning and fine cleaning on the surface of the aluminum substrate twice;

[0067] Step 4: Pure water washing: After washing twice in step 3, the surface of the aluminum substrate is further cleaned to ensure that the surface of the aluminum profile is in a pure state;

[0068] Step 5: Chromium-free passivation: After the treatment in steps 3 and 4, the surface of the aluminum substrate is passivated to form a colorless chemical conversion film.

[0069] In steps one and two, an alkaline degreasing agent is required to degrease the surface of the aluminum substrate. The alkaline degreasing agent includes the following components in parts by mass: 12 parts of scale inhibitor, 10 parts of dust suppressant, 16 parts of sodium olefin sulfonate, 6 parts of DMP-30, 10 parts of sodium hydroxide, 6 parts of potassium hydroxide and 25 parts of deionized water.

[0070] The preparation method of the alkaline degreasing agent comprises the following steps:

[0071] Step 1: Mix and stir the scale inhibitor and the dust suppressant to obtain component A, and store component A for later use;

[0072] Step 2: Mixing sodium olefin sulfonate and DMP-30 to obtain component B, and heating component B and then keeping it warm;

[0073] Step 3: Mixing and stirring sodium hydroxide and potassium hydroxide to obtain component C, and storing component C for later use;

[0074] Step 4: Mix component A, component B and component C, and add deionized water to dilute them to obtain an alkaline degreasing agent.

[0075] The etching amount of the aluminum substrate in step 2 needs to reach 1.2g / m 2 .

[0076] The conductivity of the cleaning water in step 3 needs to be controlled at 120µs / cm.

[0077] In step 4, the pH value of the pure water used for cleaning is controlled at <8, and the conductivity of the pure water is controlled at 26 us / cm.

[0078] The conversion coating in step 5 is calculated as 2 mg / m 2 .

[0079] Table 1: Implementation data of embodiments 1 to 3 of the present invention:

[0080]

[0081] 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 vertical electrostatic powder spraying alkaline pretreatment process, characterized by: Alkaline pretreatment includes the following steps: Step 1: Pre-degreasing: Clean the surface of the aluminum substrate to remove dust and impurities on the surface of the aluminum substrate and destroy the natural oxide film; Step 2: Degreasing: further removing oil stains and oxide film on the surface of the aluminum substrate, and corroding the surface of the aluminum substrate to accelerate the formation of the passivation film; in the steps 1 and 2, an alkaline degreasing agent is required to degrease the surface of the aluminum substrate, and the alkaline degreasing agent comprises the following components in parts by mass: 12-24 parts of scale inhibitor, 10-18 parts of dust suppressant, 16-34 parts of sodium olefin sulfonate, 6-15 parts of DMP-30, 10-16 parts of sodium hydroxide, 6-14 parts of potassium hydroxide and 25-35 parts of deionized water; Step 3: Cleaning: Perform preliminary cleaning and fine cleaning on the surface of the aluminum substrate twice; Step 4: Pure water washing: After washing twice in step 3, the surface of the aluminum substrate is further cleaned to ensure that the surface of the aluminum profile is in a pure state; Step 5: Chromium-free passivation: After the treatment in steps 3 and 4, the surface of the aluminum substrate is passivated to form a colorless chemical conversion film.

2. A vertical electrostatic powder spraying alkaline pretreatment process according to claim 1, characterized in that: The preparation method of the alkaline degreasing agent comprises the following steps: Step 1: Mix and stir the scale inhibitor and the dust suppressant to obtain component A, and store component A for later use; Step 2: Mixing sodium olefin sulfonate and DMP-30 to obtain component B, and heating component B and then keeping it warm; Step 3: Mixing and stirring sodium hydroxide and potassium hydroxide to obtain component C, and storing component C for later use; Step 4: Mix component A, component B and component C, and add deionized water to dilute them to obtain an alkaline degreasing agent.

3. The vertical electrostatic powder spraying alkaline pretreatment process according to claim 1, characterized in that: The etching amount of the aluminum substrate in step 2 needs to reach 0.8g / m 2 .

4. The vertical electrostatic powder spraying alkaline pretreatment process according to claim 1, characterized in that: The conductivity of the cleaning water in step 3 needs to be controlled within the range of 0-500 μs / cm.

5. The vertical electrostatic powder spraying alkaline pretreatment process according to claim 1, characterized in that: The pH value of the pure water used for cleaning in step 4 is controlled to be less than 8, and the conductivity of the pure water is controlled to be 0-100 us / cm.

6. The vertical electrostatic powder spraying alkaline pretreatment process according to claim 1, characterized in that: In step 5, the conversion film is 1-8 mg / m2 in terms of zirconium ions. 2 .

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