Method for controlling the rough surface of aluminum profile after electrolytic coloring and matte painting

Abstract

The invention discloses a method for controlling the roughness of the surface of an aluminum profile after electrolytic coloring and matte painting, comprising the following steps: step one, degreasing; step two, alkali etching; step three, neutralization; step four, anodizing; step five, electrolytic coloring; step six, sulfuric acid cleaning; step seven, matte photophoresis; step eight, drying and curing; in the step one, the concentration of H2SO4 in the degreasing sulfuric acid solution is 20-100 g / L, in the step two, the concentration of NaOH in the alkaline solution is 25-90 g / L, the concentration of Al3+ is 30- 80g / L, in the step 4, the H2SO4 concentration in the sulfuric acid solution is 150-180g / L; the AL3+ concentration is 5-20g / L, in the step 6, the H2SO4 concentration of the sulfuric acid solution is 80-100g / L, and the water cutting and draining time is 3-5min. Compared with the existing control method for the rough surface of aluminum profiles after electrolytic coloring and matte painting, the present invention adds a sulfuric acid cleaning process after electrolytic coloring, which can completely eliminate the particles on the surface of the aluminum profile after coloring and obtain a smooth surface effect.

Description

Technical Field

[0001] The invention relates to the technical field of profile processing, in particular to a method for controlling the roughness of the surface of an aluminum profile after electrolytic coloring and matte painting. Background Art

[0002] Electrolytic coloring is a process for surface treatment of aluminum profiles, one of which is black coloring. However, when black products need to be matched with a matte painting process, it is easy to have problems such as surface roughness and reduced glossiness. The method of immersing in the electrolytic coloring tank liquid cannot completely remove surface particles, resulting in a low qualified rate of products, a significant increase in production costs, and is not conducive to mass production of products. Summary of the invention

[0003] The purpose of the present invention is to provide a method for controlling the surface roughness of aluminum profiles after electrolytic coloring and matte painting, so as to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for controlling the roughness of the surface of an aluminum profile after electrolytic coloring and matte painting, comprising the following steps: step one, degreasing; step two, alkali etching; step three, neutralization; step four, anodizing; step five, electrolytic coloring; step six, sulfuric acid cleaning; step seven, matte photophoresis; step eight, drying and curing;

[0005] In the above step 1, the substrate is immersed in a sulfuric acid solution at room temperature for 3-5 minutes for degreasing treatment, and then washed once and twice with water, wherein the pH value ranges of the first and second washings are 2-4 and 4-6 respectively;

[0006] In the above step 2, the substrate is immersed in an alkaline solution at 50-60° C. for alkaline etching, and then washed once and twice, wherein the pH values ​​of the first and second washings are in the range of 8-12 and 7-9, respectively;

[0007] In the above step 3, the substrate is immersed in a sulfuric acid solution at room temperature for 2-3 minutes for neutralization treatment, and then washed with water once and twice, wherein the pH value ranges of the first and second washings are 3-5 and 4-6, respectively, to obtain a substrate that has been treated with acid and alkali;

[0008] In the above step 4, the substrate obtained in step 3 is placed in a sulfuric acid solution at 18-22° C., and then powered on with a DC voltage of 15-18V and a current density of 1.1-1.3A / dm2 for 25-30min to obtain an anodic oxide film with a thickness of 13-15μm, and then washed once and twice with water, and then washed with pure water to obtain an oxidized substrate, wherein the pH ranges of the first and second water washes are 2-3 and 4-5, respectively, and the pH range of the pure water wash is 4.6-6;

[0009] In the above step 5, the substrate obtained in step 4 is put into a coloring solution at 18-22° C., and then powered on, with an AC positive wave voltage of 16-18V and a current density of 10-20A / dm2 for 10-15 minutes, to perform a coloring treatment, so that the surface of the substrate is plated with pure black, thereby obtaining a colored substrate;

[0010] In the above step 6, the substrate obtained in step 5 is placed in a sulfuric acid solution at room temperature for sulfuric acid treatment for 2-4 minutes, and no particles remain on the surface of the substrate after cleaning, and then washed once, washed with pure water, washed with hot water, washed with pure water and drained with water to obtain a profile after surface treatment, wherein the pH value of the single water washing is in the range of 1-2.0, the pH value of the pure water washing is in the range of 2-4.0, the pH value of the hot water washing is ≥4.7, the conductivity is ≤160us / cm, and the pH value of the pure water washing is ≥4.8, and the conductivity is ≤15us / cm;

[0011] In the above step 7, the profile obtained in step 6 is put into electrophoretic paint, and electrophoresis is performed with a DC voltage of 120-160V to obtain a coating with a thickness of 7-10 μm, and then put into RO1 washing tank and RO2 washing tank for washing for 1-2 minutes until there is no floating paint on the surface of the profile, thereby obtaining a profile after electrophoresis;

[0012] In the above step eight, the profile obtained in step seven is liquid cut at room temperature for 5-20 minutes, the residual night is drained off, and then it is put into a drying furnace, the temperature is adjusted to 175-190°C, and it is dried for 22-30 minutes to solidify.

[0013] Preferably, in step 1, the concentration of the degreasing sulfuric acid solution H2SO4 is 20-100 g / L.

[0014] Preferably, in step 2, the concentration of NaOH in the alkaline solution is 25-90 g / L, and the concentration of AL3+ is 30-80 g / L.

[0015] Preferably, in step three, the concentration of the neutralized sulfuric acid solution H2SO4 is 80-180 g / L.

[0016] Preferably, in step 4, the concentration of H2SO4 in the sulfuric acid solution is 150-180 g / L; the concentration of AL3+ is 5-20 g / L.

[0017] Preferably, in step five, the coloring solution is mixed according to a SnSO4 concentration of 9 to 12 g / L, a H2SO4 concentration of 35 to 42 g / L, and a total acid concentration of 55 to 75 g / L, and a stannous ion anti-hydrolysis stabilizer is added thereto.

[0018] Preferably, in step six, the concentration of the sulfuric acid solution H2SO4 is 80-100 g / L, and the water shearing and draining time is 3-5 min.

[0019] Preferably, in step seven, the solid content in the electrophoretic paint is 9.5±0.5%, the pH value range is 8.1-8.6, and the conductivity is 650-950us / cm, the solid content in the RO1 washing tank is 0.8±0.5%, the pH value range is 8.5-9.3, and the conductivity is 300-800us / cm, and the solid content in the RO2 washing tank is 0.2±0.1%, the pH value range is 8.5-9.5, and the conductivity is ≤125us / cm.

[0020] Compared with the prior art, the beneficial effects of the present invention are: compared with the existing method for controlling the rough surface of aluminum profiles after electrolytic coloring and matte painting, the present invention adds a sulfuric acid cleaning process after electrolytic coloring, which can completely eliminate the particles on the surface of the aluminum profile after coloring and obtain a smooth surface effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 , an embodiment provided by the present invention: a method for controlling the roughness of the surface of an aluminum profile after electrolytic coloring and matte painting, comprising the following steps: step one, degreasing; step two, alkali etching; step three, neutralization; step four, anodizing; step five, electrolytic coloring; step six, sulfuric acid cleaning; step seven, matte photophoresis; step eight, drying and curing;

[0024] In the above step 1, the substrate is immersed in a sulfuric acid solution at room temperature for 3-5 minutes for degreasing treatment, and then washed once and twice with water, wherein the pH value ranges of the first and second washings are 2-4 and 4-6 respectively, and the concentration of H2SO4 in the degreasing sulfuric acid solution is 20-100 g / L;

[0025] In the above step 2, the substrate is immersed in an alkaline solution at 50-60°C for alkaline etching, and then washed once and twice, wherein the pH values ​​of the first and second washings are in the range of 8-12 and 7-9, respectively, and the concentration of NaOH in the alkaline solution is 25-90 g / L, and the concentration of AL3+ is 30-80 g / L;

[0026] In the above step 3, the substrate is immersed in a sulfuric acid solution at room temperature for 2-3 minutes for neutralization treatment, and then washed with water once and twice, wherein the pH value ranges of the first and second water washes are 3-5 and 4-6, respectively, to obtain a substrate that has been treated with acid and alkali, and the concentration of the neutralized sulfuric acid solution H2SO4 is 80-180g / L;

[0027] In the above step 4, the substrate obtained in step 3 is placed in a sulfuric acid solution at 18-22°C, and then powered on with a DC voltage of 15-18V and a current density of 1.1-1.3A / dm2 for 25-30min to obtain an anodic oxide film with a thickness of 13-15μm, and then washed once and twice with water, and then washed with pure water to obtain an oxidized substrate, wherein the pH ranges of the first and second washings are 2-3 and 4-5 respectively, and the pH range of the pure water washing is 4.6-6, and the H2SO4 concentration in the sulfuric acid solution is 150-180g / L; the AL3+ concentration is 5-20g / L;

[0028] In the above step 5, a coloring solution is prepared according to a SnSO4 concentration of 9-12 g / L, a H2SO4 concentration of 35-42 g / L, and a total acid concentration of 55-75 g / L, and an anti-hydrolysis stabilizer is added, and then the substrate obtained in step 4 is put into the coloring solution at 18-22° C., and then powered on, with an AC positive wave voltage of 16-18 V and a current density of 10-20 A / dm2 for 10-15 min, to perform a coloring treatment, so that the surface of the substrate is plated with pure black to obtain a colored substrate;

[0029] In the above step six, the substrate obtained in step five is put into a sulfuric acid solution at room temperature for sulfuric acid treatment for 2-4 minutes, and no particles remain on the surface of the substrate after cleaning, and then a water wash, a pure water wash, a hot water wash, a pure water wash and a water cut and drain are sequentially performed to obtain a profile after surface treatment, wherein the pH value range of the single water wash is 1-2.0, the pH value range of the pure water wash is 2-4.0, the pH value of the hot water wash is ≥4.7, and the conductivity is ≤160us / cm, the pH value of the pure water wash is ≥4.8, and the conductivity is ≤15us / cm, the concentration of the sulfuric acid solution H2SO4 is 80-100g / L, and the water cut and drain time is 3-5min;

[0030] In the above step seven, the profile obtained in step six is ​​put into electrophoretic paint, and electrophoresis is performed at a voltage of 120-160V to obtain a coating with a thickness of 7-10μm, and then put into RO1 washing tank and RO2 washing tank for cleaning for 1-2min until there is no floating paint on the surface of the profile, to obtain a profile after electrophoresis, wherein the solid content in the electrophoretic paint is 9.5±0.5%, the pH value range is 8.1-8.6, and the conductivity is 650-950us / cm, the solid content in the RO1 washing tank is 0.8±0.5%, the pH value range is 8.5-9.3, and the conductivity is 300-800us / cm, and the solid content in the RO2 washing tank is 0.2±0.1%, the pH value range is 8.5-9.5, and the conductivity is ≤125us / cm;

[0031] In the above step eight, the profile obtained in step seven is liquid cut at room temperature for 5-20 minutes, the residual night residue on the surface is drained, and then it is put into a drying furnace, the temperature is adjusted to 175-190°C, and it is dried for 22-30 minutes to solidify.

[0032] Based on the above, the advantage of the present invention is that when treating the surface of the colored aluminum profile, by adding a sulfuric acid cleaning process, the purpose of completely removing surface particles is achieved, which solves the shortcomings of the prior art and meets the needs of mass production of products.

[0033] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for controlling the roughness of the surface of aluminum profiles after electrolytic coloring and matte painting, comprising the following steps: Step 1, degreasing; Step 2, alkaline etching; Step 3, neutralization; Step 4, anodizing; Step 5, electrolytic coloring; Step 6, sulfuric acid cleaning; Step 7, extinction electrophoresis; Step 8, drying and curing; It is characterized by: In the above step 1, the substrate is immersed in a sulfuric acid solution at room temperature for 3-5 minutes for degreasing treatment, and then washed once and twice with water, wherein the pH value ranges of the first and second washings are 2-4 and 4-6 respectively; In the above step 2, the substrate is immersed in an alkaline solution at 50-60° C. for alkaline etching, and then washed once and twice, wherein the pH values ​​of the first and second washings are in the range of 8-12 and 7-9, respectively; In the above step 3, the substrate is immersed in a sulfuric acid solution at room temperature for 2-3 minutes for neutralization treatment, and then washed with water once and twice, wherein the pH value ranges of the first and second washings are 3-5 and 4-6, respectively, to obtain a substrate that has been treated with acid and alkali; In the above step 4, the substrate obtained in step 3 is placed in a sulfuric acid solution at 18-22°C, and then powered on with a DC voltage of 15-18V and a current density of 1.1-1.3A / dm 2 , continuing for 25-30 minutes, obtaining an anodic oxide film with a thickness of 13-15 μm, and then performing a first water wash and a second water wash, and then a pure water wash to obtain an oxidized substrate, wherein the pH value ranges of the first water wash and the second water wash are 2-3 and 4-5 respectively, and the pH value range of the pure water wash is 4.6-6; In the above step 5, the substrate obtained in step 4 is placed in a coloring solution at 18-22°C, and then powered on, with an AC sinusoidal voltage of 16-18V and a current density of 10-20A / dm 2 , continuing for 10-15 minutes, performing coloring treatment, so that the surface of the substrate is plated with pure black, and a colored substrate is obtained; In the above step six, the substrate obtained in step five is put into a sulfuric acid solution at room temperature for sulfuric acid treatment for 2-4 minutes, and no particles remain on the surface of the substrate after cleaning, and then a water wash, a pure water wash, a hot water wash, a pure water wash and a water cut and drain are sequentially performed to obtain a profile after surface treatment, wherein the pH value range of the single water wash is 1-2.0, the pH value range of the pure water wash is 2-4.0, the pH value of the hot water wash is ≥4.7, and the conductivity is ≤160us / cm, the pH value of the pure water wash is ≥4.8, and the conductivity is ≤15us / cm, the concentration of the sulfuric acid solution H2SO4 is 80-100g / L, and the water cut and drain time is 3-5min; In the above step 7, the profile obtained in step 6 is put into electrophoretic paint, and electrophoresis is performed with power on, the DC voltage soft start is 120-160V, the time is 3-5min, and a coating with a thickness of 7-10μm is obtained, and then it is put into RO1 washing tank and RO2 washing tank for washing for 1min until there is no floating paint on the surface of the profile, and the profile after electrophoresis is obtained; In the above step eight, the profile obtained in step seven is liquid cut at room temperature for 5-20 minutes, the residual night is drained off, and then it is put into a drying furnace, the temperature is adjusted to 175-190°C, and it is dried for 22-30 minutes to solidify.

2. The method for controlling the roughness of the surface of aluminum profile after electrolytic coloring and matte painting according to claim 1, characterized in that: In the step 1, the concentration of the degreasing sulfuric acid solution H2SO4 is 20-100 g / L.

3. The method for controlling the roughness of the surface of aluminum profile after electrolytic coloring and matte painting according to claim 1, characterized in that: In the step 2, the concentration of NaOH in the alkaline solution is 25-90 g / L, and the concentration of Al 3+ The concentration is 30~80g / L.

4. The method for controlling the roughness of the surface of aluminum profile after electrolytic coloring and matte painting according to claim 1, characterized in that: In the step 3, the concentration of the neutralized sulfuric acid solution H2SO4 is 80-180 g / L.

5. The method for controlling the roughness of the surface of aluminum profile after electrolytic coloring and matte painting according to claim 1, characterized in that: In step 4, the concentration of H2SO4 in the sulfuric acid solution is 150-180 g / L; Al 3+ The concentration is 5~20g / L.

6. The method for controlling the roughness of the surface of aluminum profile after electrolytic coloring and matte painting according to claim 1, characterized in that: In the step 5, the coloring solution is mixed according to a SnSO4 concentration of 9 to 12 g / L, a H2SO4 concentration of 35 to 42 g / L, and a total acid concentration of 55 to 75 g / L, and a stabilizer to prevent hydrolysis of stannous ions is added thereto.

7. The method for controlling the roughness of the surface of aluminum profile after electrolytic coloring and matte painting according to claim 1, characterized in that: In the step seven, the solid content of the electrophoretic paint is 9.5±0.5%, the pH value range is 8.1-8.6, and the conductivity is 650-950us / cm; the solid content of the RO1 washing tank is 0.8±0.5%, the pH value range is 8.5-9.3, and the conductivity is 300-800us / cm; the solid content of the RO2 washing tank is 0.2±0.1%, the pH value range is 8.5-9.5, and the conductivity is ≤125us / cm.

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