CN-122013267-A - Acid and alkali resistant high-corrosion-resistance composite protective coating for hardware fitting and preparation method thereof

Abstract

The invention discloses a composite protective coating for acid and alkali resistant high-corrosion-resistance hardware fittings and a preparation method thereof. The composite coating structure comprises a galvanized layer and an epoxy coating, wherein the galvanized layer and the epoxy coating are formed on the surface of the iron-based hardware fitting. The preparation method comprises the steps of firstly carrying out alkaline electroplating treatment on the iron-based hardware fitting to form a galvanized layer with the thickness of 5-7 mu m, then fully immersing the galvanized hardware fitting into epoxy paint, uniformly coating by adopting a dip-coating centrifugal mode, baking and solidifying at 200-240 ℃ to form an epoxy coating, and repeatedly coating to ensure that the total thickness of the epoxy coating reaches more than 10 mu m to obtain the composite protective coating. According to the invention, through the synergistic effect of alkaline electroplating and the functional epoxy coating and the combination of a specific dip coating process, the coating has excellent adhesive force, impact resistance, high hardness, long-acting corrosion resistance and acid and alkali resistance, can replace a stainless steel fitting, remarkably reduces the manufacturing cost of the communication fitting, and is suitable for long-acting protection in a severe corrosion environment.

Inventors

• ZHANG PINGAN
• LI GANG
• ZHANG YONGGANG

Assignees

• 浙江铂翊新材料有限公司

Dates

Publication Date

20260512

Application Date

20260228

Claims (9)

1. 1. The preparation method of the composite protective coating for the acid and alkali resistant high-corrosion-resistance hardware fitting is characterized by comprising the following steps of: Step 1, performing alkaline electroplating treatment on the surface of an iron-based hardware fitting to form a galvanized layer with the thickness of 5-7 mu m, so as to obtain the galvanized hardware fitting; step 2, completely immersing the galvanized hardware fitting into epoxy paint, uniformly coating in a dip-coating centrifugal mode, and baking and curing the coated hardware fitting to form an epoxy coating; And step 3, repeating the step 2 to enable the total thickness of the epoxy coating to reach more than 10 mu m, and finally obtaining the composite protective coating for the acid-base-resistant high-corrosion-resistance hardware fitting.
2. 2. The preparation method of the composite protective coating for the acid and alkali resistant high corrosion resistant hardware fitting, which is characterized in that the alkaline electroplating in the step 1 is a cyanide-free alkaline zinc plating process, and the plating solution comprises 8-15g/L of zinc oxide, 80-150g/L of sodium hydroxide, 0.5-5mL/L of special gloss additive, 4-12mL/L of auxiliary additive and the balance of deionized water.
3. 3. The method for preparing the composite protective coating for the acid and alkali resistant high corrosion resistant hardware fitting, which is characterized in that the alkaline electroplating treatment in the step 1 is specifically electroplating for 15-25min under the conditions of current density of 2-4A/dm < 2 > and temperature of 25-35 ℃.
4. 4. The preparation method of the acid and alkali resistant high corrosion resistance hardware fitting composite protective coating according to claim 1 is characterized in that the epoxy coating in the step 2 comprises, by weight, 30-35 parts of modified epoxy resin, 25-30 parts of amino resin, 25-30 parts of diluent, 2-5 parts of zinc powder, 12-16 parts of aluminum paste, 2-4 parts of BYK auxiliary agent and 6-8 parts of other auxiliary agents.
5. 5. The method for preparing the composite protective coating for the acid and alkali resistant high corrosion resistant hardware fitting according to claim 1, wherein the baking temperature in the step 2 is 200-240 ℃ and the time is 35-45min.
6. 6. The method for preparing the composite protective coating for the acid and alkali resistant high corrosion resistance hardware fitting, which is characterized in that the total thickness of the composite coating is more than 15 mu m.
7. 7. The method for preparing the acid and alkali resistant high corrosion resistance hardware fitting composite protective coating according to claim 4, wherein the BYK auxiliary agent is a mixture of BYK-306 leveling agent and BYK-141 defoamer, and the weight ratio of the BYK-306 leveling agent to the BYK-141 defoamer is 1:1.
8. 8. The method for preparing the acid and alkali resistant high corrosion protection hardware fitting composite protective coating according to claim 4, wherein the diluent is a mixed solvent of propylene glycol methyl ether acetate and dimethylbenzene, and the weight ratio of the mixed solvent is 1:1.
9. 9. The method for preparing the composite protective coating for the acid and alkali resistant high corrosion resistant hardware fitting according to claim 4, wherein the other auxiliary agents are mixed solvents of KH-560, zinc phosphate and synthetic silica matting powder, and the weight ratio of the mixed solvents is 1:1:1.

Description

Acid and alkali resistant high-corrosion-resistance composite protective coating for hardware fitting and preparation method thereof Technical Field The invention relates to the technical field of functional protective coating materials, in particular to a composite protective coating for acid and alkali resistant high-corrosion-resistance hardware fittings and a preparation method thereof. Background The communication hardware is a key structural member for connecting, fixing and protecting cables and equipment in a communication network, and has to have excellent corrosion resistance and acid-base resistance when exposed to outdoor atmosphere and various corrosion environments for a long time. At present, common hardware fittings in the market are mostly made of stainless steel materials, the corrosion resistance is good, the cost is high, in order to reduce the cost, the industry gradually turns to iron-based materials, but the long-acting protection requirement is met by a surface protection coating, so that the development of a high-performance composite coating suitable for the iron-based hardware fittings becomes a technical focus. In the prior art, the electrogalvanizing is a common anti-corrosion means, wherein the acid electroplating process has the problems of poor deep plating capability, easy hydrogen embrittlement and corrosion to a substrate, poor binding force of a coating and the like, and compared with the cyanide-free alkaline electrogalvanizing process which adopts sodium hydroxide as a complexing agent, the cyanide-free alkaline electrogalvanizing has the advantages of stable plating solution, environmental protection, uniform and compact coating, strong deep plating capability, good binding force with a substrate and the like, but the chemical corrosion resistance and long-acting protection capability of a single coating are still insufficient. Another common technology is epoxy coating, which has strong coating adhesion and outstanding chemical resistance, but the traditional spraying mode has high cost, difficult uniformity control and limited long-term protection reliability when being independently used on the iron-based surface. Therefore, in the prior art, a preparation method which can combine the advantages of alkaline electroplating and epoxy coating and realize uniform and stable compounding of the coating through a high-efficiency and low-cost coating process is needed, so that the cost reduction and efficiency enhancement of the iron-substituted stainless steel can be truly realized while the service requirement of a severe environment is met. Disclosure of Invention Aiming at the problems, the invention provides the composite protective coating for the acid and alkali resistant high-corrosion-resistance hardware and the preparation method thereof, and the compact galvanized layer and the chemical corrosion resistant epoxy layer are sequentially formed on the surface of the iron-based hardware, so that the long-acting composite protection with high corrosion resistance and acid and alkali resistance is realized, and the manufacturing cost of the communication hardware is remarkably reduced. The process adopts repeated dip coating and high-temperature curing, ensures that the coating is uniform and compact, and the comprehensive performance reaches and exceeds the protection level of the stainless steel fitting. The invention can be realized by the following technical scheme: The preparation method of the acid and alkali resistant high-corrosion-resistance composite protective coating for hardware fitting comprises the following steps: Step 1, performing alkaline electroplating treatment on the surface of an iron-based hardware fitting to form a galvanized layer with the thickness of 5-7 mu m, so as to obtain the galvanized hardware fitting; step 2, completely immersing the galvanized hardware fitting into epoxy paint, uniformly coating in a dip-coating centrifugal mode, and baking and curing the coated hardware fitting to form an epoxy coating; And step 3, repeating the step 2 to enable the total thickness of the epoxy coating to reach more than 10 mu m, and finally obtaining the composite protective coating for the acid-base-resistant high-corrosion-resistance hardware fitting. Preferably, the alkaline electroplating in the step 1 is a cyanide-free alkaline zinc plating process, and the plating solution comprises 8-15g/L of zinc oxide, 80-150g/L of sodium hydroxide, 0.5-5mL/L of special gloss additive, 4-12mL/L of auxiliary additive and the balance of deionized water. Preferably, the alkaline electroplating treatment in the step 1 is specifically electroplating for 15-25min under the conditions of current density of 2-4A/dm < 2 > and temperature of 25-35 ℃. Preferably, the epoxy coating in the step 2 comprises, by weight, 30-35 parts of modified epoxy resin, 25-30 parts of amino resin, 25-30 parts of diluent, 2-5 parts of zinc powder, 12-16 parts of aluminum paste, 2-4 par