A high-temperature nickel-free sealing agent and sealing process

Abstract

The present invention relates to a high-temperature nickel-free sealing agent and a sealing process. The high-temperature nickel-free sealing agent includes a first component and a second component, wherein the first component is composed of 20-50 g / L of silicate, 10-30 g / L of surfactant, and 0.1-2 g / L of sodium polystyrene sulfonate, and the second component is composed of 20-50 g / L of silicate, 10-30 g / L of surfactant, and 5-60 g / L of aminobenzenesulfonate. The first component and the second component are aqueous solutions, and the pH is adjusted to 5.5-6.0 by acetic acid or ammonia water. The present invention can achieve a good sealing effect on thick anodized films.

Description

Technical Field

[0001] The invention relates to a high-temperature nickel-free sealing agent and a sealing process. Background Art

[0002] Aluminum alloy products have a very wide range of applications, but aluminum products are easily corroded. In order to avoid the corrosion of aluminum alloy products, anodizing technology is widely used in actual industrial production. Aluminum alloy materials after anodizing treatment have the advantages of bright color, high hardness and corrosion resistance.

[0003] High-temperature sealing, also known as boiling water sealing, involves hydrating the oxide film on the aluminum surface to form boehmite, a substance with excellent corrosion resistance. During the hydration reaction, the oxide film molecules expand, sealing the film's micropores. This method is simple and provides exceptionally high sealing quality. To achieve optimal color effects, anodized films often require a certain thickness. However, due to the expansion of the oxide film molecules and residual chemicals, thicker anodized films are more difficult to seal, resulting in poor sealing results. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a high-temperature nickel-free sealing agent. The high-temperature nickel-free sealing agent comprises a first component and a second component, wherein the first component consists of 20-50 g / L of silicate, 10-30 g / L of surfactant and 0.1-2 g / L of sodium polystyrene sulfonate, and the second component consists of 20-50 g / L of silicate, 10-30 g / L of surfactant and 5-60 g / L of aminobenzenesulfonate. The first component and the second component are aqueous solutions and the pH is adjusted to 5.5-6.0 by acetic acid or ammonia water.

[0005] The weight average molecular weight of the sodium polystyrene sulfonate is 5,000-80,000.

[0006] The silicate is selected from one or both of sodium silicate and potassium silicate.

[0007] The aminobenzenesulfonate is selected from one or more of sodium 4-(methylamino)benzenesulfonate, sodium 4-(ethylamino)benzenesulfonate, and sodium 3-(ethylamino)-4-methylbenzenesulfonate.

[0008] The surfactant is selected from one or more of polyoxyethylene alkyl ether sulfates, linear alkylbenzene sulfonates, alkyl sulfates, alcohol sulfates, secondary alkane sulfonates, α-olefin sulfonates, α-sulfo fatty acid ester salts, fatty acid polyoxyethylene ether sulfates, and polyoxyethylene alkyl ether carboxylates.

[0009] A high-temperature nickel-free sealing process comprises the following steps:

[0010] The first component is used to seal the metal substrate having an anodic oxide film to obtain a pretreated substrate, and the sealing parameters are: 1-10 minutes at 90-98° C.;

[0011] The second component is used to perform high-temperature sealing on the pretreated substrate, and the sealing parameters are: 90-98°C for 10-60 minutes;

[0012] The first component consists of 20-50 g / L of silicate, 10-30 g / L of surfactant and 0.1-2 g / L of sodium polystyrene sulfonate, and the second component consists of 20-50 g / L of silicate, 10-30 g / L of surfactant and 5-60 g / L of aminobenzenesulfonate. The first component and the second component are aqueous solutions and the pH is adjusted to 5.5-6.0 by acetic acid or ammonia water.

[0013] The weight average molecular weight of the sodium polystyrene sulfonate is 5,000-80,000.

[0014] The aminobenzenesulfonate is selected from one or more of sodium 4-(methylamino)benzenesulfonate, sodium 4-(ethylamino)benzenesulfonate, and sodium 3-(ethylamino)-4-methylbenzenesulfonate.

[0015] The present invention can have a good sealing effect on thick anodic oxidation films.

[0016] The above and other features, aspects and advantages of the present application will be more readily understood with reference to the following detailed description. DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described 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.

[0018] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the present patent application specification and claims do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a limitation of quantity, but rather denote the presence of at least one.

[0019] A high-temperature nickel-free sealing agent comprises a first component and a second component, wherein the first component consists of 20-50 g / L of silicate, 10-30 g / L of surfactant and 0.1-2 g / L of sodium polystyrene sulfonate, and the second component consists of 20-50 g / L of silicate, 10-30 g / L of surfactant and 5-60 g / L of aminobenzenesulfonate. The first component and the second component are aqueous solutions, and the pH is adjusted to 5.5-6.0 by acetic acid or ammonia water.

[0020] The weight average molecular weight of the sodium polystyrene sulfonate is 5,000-80,000.

[0021] The silicate is selected from one or both of sodium silicate and potassium silicate.

[0022] The aminobenzenesulfonate is selected from one or more of sodium 4-(methylamino)benzenesulfonate, sodium 4-(ethylamino)benzenesulfonate, and sodium 3-(ethylamino)-4-methylbenzenesulfonate.

[0023] The surfactant is selected from one or more of polyoxyethylene alkyl ether sulfates, linear alkylbenzene sulfonates, alkyl sulfates, alcohol sulfates, secondary alkane sulfonates, α-olefin sulfonates, α-sulfo fatty acid ester salts, fatty acid polyoxyethylene ether sulfates, and polyoxyethylene alkyl ether carboxylates.

[0024] Metal surface treatment process:

[0025] Chemical polishing

[0026] The degreased and dewaxed metal material was immersed in a solution consisting of 650 g / L phosphoric acid and 200 g / L sulfuric acid for chemical polishing for 3 seconds, and then immediately immersed in water to clean the residual acid on the surface of the substrate. The substrate was then immersed in a 10 g / L sodium hydroxide solution for 8 minutes, and then immediately immersed in water to clean the residual alkali on the surface of the substrate.

[0027] Anodizing

[0028] The treated substrate was immersed in an electrolytic cell containing an aqueous solution of 180 g / L sulfuric acid and 8 g / L aluminum sulfate, with the substrate as the anode, at a voltage of 20 V and a current density of 2 A / dm 2 , anodize at a temperature of 20° C. for 60 minutes, take out and clean after anodization is completed to obtain a metal substrate with a thick anodized film (32-40 μm).

[0029] dyeing

[0030] Organic dye: 6g / L, sodium acetate 1g / L. Temperature 55-60℃, treatment time 10 minutes.

[0031] Sealing

[0032] Randomly select 5 metal substrates with thick anodized films and immerse them in the first component and the second component of the following examples and the sealing agent of the comparative example, with the first component at 90-98°C for 5 minutes and the second component at 90-98°C for 30 minutes.

[0033] The sealing effect is tested using a weight loss test. According to the standard GB / T5237.2-2000, frost spots on the sample surface are wiped off with a dry cloth. The sample is then degreased with an appropriate organic solvent at room temperature, dried, and weighed. The sample is then immersed in a 38±1°C phosphochromic acid solution for 15 minutes. The sample is then removed, cleaned, dried, and weighed again. The weight loss is calculated. A weight loss of 20 mg / dm² or less is considered acceptable.

[0034] Example 1

[0035] The first component consisted of 40 g / L sodium silicate, 20 g / L fatty acid polyoxyethylene ether sulfate surfactant, and 0.5 g / L sodium polystyrene sulfonate (molecular weight 70,000). The second component consisted of 40 g / L silicate, 20 g / L fatty acid polyoxyethylene ether sulfate surfactant, and 20 g / L sodium 4-(methylamino)benzenesulfonate. The experimentally calculated weight loss was 8.13%.

[0036] Example 2

[0037] The first component consisted of 40 g / L sodium silicate, 20 g / L fatty acid polyoxyethylene ether sulfate surfactant, and 0.7 g / L sodium polystyrene sulfonate (molecular weight 70,000). The second component consisted of 40 g / L silicate, 20 g / L fatty acid polyoxyethylene ether sulfate surfactant, and 30 g / L sodium 4-(methylamino)benzenesulfonate. The experimentally obtained weight loss was 7.29%.

[0038] Comparative Example 1

[0039] Only one component was used: 40 g / L silicate, 20 g / L fatty acid polyoxyethylene ether sulfate surfactant, and 20 g / L sodium 4-(methylamino)benzenesulfonate. The weight loss obtained by the experiment was 16.23%.

[0040] Comparative Example 2

[0041] The same as Example 1, except that sodium 4-(methylamino)benzenesulfonate was replaced by sodium hexadecyl diphenyl ether disulfonate, was used. The weight loss obtained by the experiment was 19.05%.

[0042] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all changes that come within the meaning and range of equivalents of the claims be included therein.

[0043] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A high-temperature nickel-free sealing process, characterized in that: The following steps are involved: Chemical polishing of metal substrates; Anodizing the polished metal substrate to obtain an anodic oxide film with a thickness of 32-40 microns; Dyeing of anodized metal substrates; The dyed metal substrate is sealed, and the sealing comprises the following steps: The first component of the high-temperature nickel-free sealing agent is used to seal the metal substrate having the anodic oxide film to obtain a pretreated substrate. The sealing parameters are: 1-10 minutes at 90-98° C.; The second component of the high-temperature nickel-free sealant is used to seal the pretreated metal substrate at high temperature, and the sealing parameters are: 10-60 minutes at 90-98°C; The first component of the high-temperature nickel-free sealing agent consists of 40g / L silicate, 20g / L surfactant and 0.5-0.7g / L sodium polystyrene sulfonate; The second component of the high-temperature nickel-free sealing agent consists of 40g / L of silicate, 20g / L of surfactant and 20-30g / L of sodium 4-(methylamino)benzenesulfonate; The first component of the high-temperature nickel-free sealing agent and the second component of the high-temperature nickel-free sealing agent are both aqueous solutions, and the pH is adjusted to 5.5-6.0 by acetic acid or ammonia water; the weight average molecular weight of the sodium polystyrene sulfonate is 5000-80000.

2. A high-temperature nickel-free sealing process according to claim 1, characterized in that: The surfactant is selected from one or more of polyoxyethylene alkyl ether sulfates, linear alkylbenzene sulfonates, alkyl sulfates, alcohol sulfates, secondary alkane sulfonates, α-olefin sulfonates, α-sulfo fatty acid ester salts, fatty acid polyoxyethylene ether sulfates, and polyoxyethylene alkyl ether carboxylates.