Nickel plating sealing agent and preparation method and application thereof

Abstract

The invention provides a nickel plating sealing agent, which is prepared from the following raw material components in percentage by weight: 35 to 47 percent of amine, 4 to 5.5 percent of low-grade polyol, 12 to 18 percent of polyethylene glycol 400, 0.4 to 1.2 percent of ternary polycarboxylic acid, 0.3 to 0.8 percent of N, N-methylene dimorpholine, 2 to 3 percent of boric acid and the balance of deionized water. The sealing agent provided by the invention is simple in preparation method, environment-friendly and high-temperature-resistant, can be used for surface treatment of the nickel-plated diamond cutting wire, and can greatly improve the corrosion resistance of the nickel-plated diamond cutting wire.

Description

Technical Field

[0001] The invention relates to the technical field of surface treatment, and more specifically to a nickel plating sealant and a preparation method and application thereof. Background Art

[0002] Electroplated nickel has excellent corrosion and wear resistance. It is often used as a conductive, decorative, protective or functional layer for components and is used in various fields such as aerospace, national defense and military, consumer electronics, petrochemicals and civil construction. Nickel plating is a cathode plating layer. Only when the plating layer has no pores can it play a complete mechanical protection role. The thickness of nickel plating without pores is generally above 24um, which is expensive and difficult to achieve for most parts. At present, the process of copper plating as a base and then thin bright nickel plating is generally adopted. The bright nickel plating layer is only 4-5 microns, and pores are inevitable. The corrosive medium passes through the pores, first corroding the copper base layer, and then corroding the iron matrix. The corrosion resistance of the coating is poor, and it is often necessary to use a sealant to improve its corrosion resistance.

[0003] Currently, the commonly used chromium-free nickel plating sealers are divided into two categories: one is a water-based anti-rust sealer. The other is an oily anti-rust sealer, which has a better anti-rust sealing effect than a water-based anti-rust sealer, but has problems such as odor, greasiness, and safety. Chinese patent CN 112410838A discloses a water-based electroplating nickel sealer, which has a low working temperature and is difficult to be used in a high-temperature working environment. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a nickel plating sealant and its preparation method and application. The sealant is an aqueous solution, colorless, transparent, odorless, non-toxic, non-flammable, alkaline (pH = 9-11), and is easy to react with the metal surface to form a film. When the water in the solution evaporates, a water-insoluble hard film can be generated, which plays a good anti-rust sealing role on the pores of the nickel plating layer. It is suitable for high working temperatures and can be used for nickel-plated diamond cutting wire surfaces.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] A nickel plating sealant, the raw material components of which are calculated by weight percentage:

[0007] Alkanolamine 35-47%, low polyol 4-5.5%, polyethylene glycol 40012-18%, ternary polycarboxylic acid 0.4-1.2%, N, N-methylenebismorpholine 0.3-0.8%, boric acid 2-3%, and deionized water as the balance.

[0008] Furthermore, the raw material components include, by weight percentage: 42-45% of alcohol amine, 4-5.5% of low polyol, 12-18% of polyethylene glycol 400, 0.4-1.2% of ternary polycarboxylic acid, 0.3-0.8% of N,N-methylenebismorpholine, 2-3% of boric acid, and the balance of deionized water.

[0009] Furthermore, the alcohol amine is any one or more of triethanolamine, N-methylmonoethanolamine, and diethanolamine.

[0010] Furthermore, the lower polyol is any one or both of glycerol or propylene glycol.

[0011] In the present invention, the ternary polycarboxylic acid plays a role in two aspects: one is a chemical effect, the rust-proof additive can inhibit any one or both of the anode and cathode reactions to play a rust-proof role; the other is a physical effect, the ternary polycarboxylic acid is an organic compound with polar groups and relatively long hydrocarbon chains, and it is a surfactant composed of asymmetric polar and non-polar parts. The polar group has a strong affinity with polar substances such as metal oxides and water, and can physically or chemically react with the oxide film of the metal matrix to form an adsorbed rust-proof film, while the non-polar group has a hydrophobic property, which can block the contact between the corrosive medium and the metal surface, thereby playing a rust-proof role on the metal.

[0012] The preparation method of the above-mentioned nickel plating sealant comprises the following steps:

[0013] Dissolve ethanolamine, polyethylene glycol 400 and low polyol in deionized water respectively to obtain solution A; dissolve ternary polycarboxylic acid, N,N-methylenebismorpholine and boric acid in deionized water to obtain solution B; mix solution A and solution B, stir evenly, stand and filter to obtain the solution.

[0014] The present invention preferentially uses triethanolamine as the main film-forming component, and the film-forming product emulsified with triethanolamine has the characteristics of fine film layer and bright white. In addition, the colloidal phase stability of triethanolamine and ternary polycarboxylic acid is good, the product quality is stable, and the proportion of added components is high. The addition of ternary polycarboxylic acid can improve the film-forming reaction of triethanolamine, strengthen the integrity and compactness of the film, and the adhesion to the coating. N, N-methylenebismorpholine is not only a corrosion inhibitor for the bottom copper, but also can be combined with nickel metal atoms to form a protective film, further improving the compactness and continuity of the film. N, N-methylenebismorpholine also has a synergistic effect to enhance the corrosion inhibition effect. Polyethylene glycol 400 is easily soluble in water, is a wetting agent and viscosity regulator for the solution, is conducive to the formation of a closed film, and can be matched with glycerol to improve the anti-corrosion effect.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] The nickel plating sealant provided by the present invention is environmentally friendly, safe, stable, not prone to gelation, and has a significant anti-corrosion effect on nickel-plated parts, especially a good protective effect on nickel-plated diamond cutting wires. It can be used to seal holes of various metal or plastic workpieces, can quickly disperse water drops or water films on the surface, thereby improving water stains formed when the workpiece is dried, and can effectively delay the oxidation and discoloration of the metal surface in the air, thereby improving the anti-rust and anti-discoloration capabilities of the coating, and does not affect the gloss and physical properties of the metal surface. It has been tested to have a high salt spray resistance and can withstand high temperatures of 100-200°C without discoloration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a test diagram of the nickel-plated diamond cutting wire in the present invention under simulated salt spray working conditions;

[0018] Wherein, a, blank control, 24h; b, immersion in the nickel plating sealant prepared in Example 7, 366h. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0020] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0021] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0022] Examples 1-8 and Comparative Examples 1-7

[0023] A nickel plating sealant is composed of the following raw material components: alcohol amine, low-grade polyol, polyethylene glycol 400, ternary polycarboxylic acid, N,N-methylenebismorpholine, boric acid and deionized water.

[0024] Wherein, the alcohol amine is any one or more of triethanolamine, N-methylmonoethanolamine, and diethanolamine; and the low polyol is any one or both of propylene glycol and glycerol.

[0025] The components and contents of the nickel plating sealants of Examples 1-8 and Comparative Examples 1-7 are shown in Table 1.

[0026] Its preparation method is:

[0027] Dissolve triethanolamine, polyethylene glycol 400 and propylene glycol in deionized water respectively to obtain solution A; dissolve ternary polycarboxylic acid, N,N-methylenebismorpholine and boric acid in deionized water to obtain solution B; mix solution A and solution B, stir evenly, stand and filter to obtain the solution.

[0028] Table 1

[0029]

[0030] Performance Testing

[0031] Testing process:

[0032] 1. Immerse the nickel-plated diamond cutting wire in alcohol and clean it in an ultrasonic cleaner for 10 minutes to completely remove the original impurities and other chemical reagents on the surface, and dry it for later use;

[0033] 2. The sealant should be added at 60ml / L.

[0034] 3. Dissolve 30ml of the sealant in 45℃ hot water and add it to a 500ml beaker. Keep the solution warm to 45℃ to stabilize.

[0035] 4. Immerse the dried sample wire in the sealant solution for 10-15 seconds;

[0036] 5. Take out the sample wire, air dry it, bake it in an oven at 100-110℃ for 10 minutes, and then wind it up.

[0037] Test conditions:

[0038] The nickel-plated diamond cutting wire coated with the sealant prepared in the embodiment and the comparative example and the nickel-plated diamond cutting wire not coated with the sealant were respectively exposed to the simulated salt spray test conditions (temperature of 100° C.) for a period of time. After wiping with alcohol, the surface conditions were observed and recorded as shown in Table 2.

[0039] Table 2

[0040]

[0041] like Figure 1 As shown, the nickel-plated diamond cutting wire that was not immersed in the nickel-plated sealant was rusted in 24 hours under the simulated salt spray working condition, while the cutting wire immersed in the nickel-plated sealant prepared in Example 7 was not rusted after wiping with alcohol under the simulated salt spray working condition for 366 hours.

[0042] As shown in Table 2, the dosage of triethanolamine in Comparative Example 1 is relatively low, only 33%, and the pH is low, which cannot provide good alkali buffering performance, resulting in reduced corrosion resistance. The dosage of boric acid in Comparative Example 2 is too high, and no boric acid is added in Comparative Example 3, both of which lead to reduced corrosion resistance. This is because boric acid is used as a pH buffer. If the dosage is too high or too low, the pH will be low or low, deviating from the optimal rust and corrosion inhibition pH value of 9 to 10. In Comparative Example 4, polyethylene glycol 400 (as a co-wetting agent) was not added, and the lack of wetting effect resulted in a reduction in surface erosion time. In Comparative Example 5, N, N-methylenebismorpholine was not added, and it can be seen that the surface erosion time is greatly reduced. This is because N, N-methylenebismorpholine can improve the compactness of the film formed by triethanolamine and trivalent polycarboxylic acid; at the same time, the time from oxidation of the coating to the appearance of rust is equivalent to that of the blank control, indicating that the addition of N, N-methylenebismorpholine in the present application can not only improve the corrosion resistance of the surface layer of the cutting line (the protective layer formed by the sealant), but also improve the antioxidant properties of the coating. In Comparative Example 6, trivalent polycarboxylic acid was not added, and it was impossible to react with triethanolamine to form a film-forming functional group, resulting in a decrease in the corrosion resistance of the protective film formed by the sealant. In Comparative Example 7, glycerol was not added, and the surface erosion time was reduced. The nickel-plated sealant prepared in the embodiment has a surface protective layer formed therein, which has a higher operating temperature (100°C), which meets the working environment of the nickel-plated diamond cutting line, and has good salt corrosion resistance, which can improve the service life of the nickel-plated diamond cutting line.

[0043] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A nickel plating sealant, characterized in that The raw material components include, by weight percentage, 35-47% of alcohol amine, 4-5.5% of low polyol, 12-18% of polyethylene glycol 400, 0.4-1.2% of ternary polycarboxylic acid, 0.3-0.8% of N,N-methylenebismorpholine, 2-3% of boric acid and the balance of deionized water.

2. The nickel plating sealant according to claim 1, characterized in that: The raw material components include, by weight percentage, 42-45% of alcohol amine, 4-5.5% of low polyol, 12-18% of polyethylene glycol 400, 0.4-1.2% of ternary polycarboxylic acid, 0.3-0.8% of N,N-methylenebismorpholine, 2-3% of boric acid and the balance of deionized water.

3. The nickel plating sealant according to claim 1 or 2, characterized in that: The alcohol amine is any one or more of triethanolamine, N-methylmonoethanolamine and diethanolamine.

4. The nickel plating sealant according to claim 1 or 2, characterized in that: The lower polyol is any one or both of glycerol or propylene glycol.

5. The method for preparing the nickel plating sealant according to any one of claims 1 to 4, characterized in that: The following steps are involved: Dissolve ethanolamine, polyethylene glycol 400 and low polyol in deionized water to obtain solution A; Dissolve ternary polycarboxylic acid, N,N-methylenebismorpholine and boric acid in deionized water to obtain solution B; mix solution A and solution B, stir evenly, let stand and filter to obtain the solution.

6. Use of the nickel plating sealant according to any one of claims 1 to 4 in the surface treatment of nickel-plated diamond cutting wire.

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