1. A sealant for corrosion-resistant electroplated nickel layer, which is characterized in that: the preparation method comprises the steps of adding the polyisocyanate monomer, the polyol, the nano polytetrafluoroethylene, the catalyst, the dispersing agent and the nano polytetrafluoroethylene into the ester solvent, adding the polyol again, heating to 70-80 ℃, reacting for 1-3h, and cooling and storing the product.

2. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: the ratio of the polyisocyanate monomer to the polyol is 1: 1.5-1.8.

3. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: the catalyst is 3-5% of polyisocyanate monomer, the nano polytetrafluoroethylene is 10-15% of polyisocyanate monomer, and the dispersant is 5-8% of polyisocyanate monomer.

4. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: during the synthesis, at least one of caprolactam or phenol is also added dropwise.

5. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: the polyalcohol is dihydric alcohol or trihydric alcohol, and the dihydric alcohol is at least one of dipropylene glycol and neopentyl glycol.

6. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: the polyol is polyether polyol or polyester polyol.

7. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: the polyisocyanate monomer comprises at least one of MDI, TDI, IPDI and HDI.

8. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: when the polyisocyanate monomer reacts with the polyol, a stabilizer is also added, and the amount of the stabilizer is 0.5-1% of that of the polyol.

9. The sealant for corrosion-resistant electroplated nickel layer according to claim 1, characterized in that: the catalyst is one of dibutyltin dilaurate and organic catalyst.

Background

Electroplating nickel is the electrochemical method used to deposit a nickel protective layer on the surface of a workpiece. Can prevent the corrosion of the workpiece, increase the wear resistance and luster and beautify the appearance. However, the poor problems of electroplated nickel are mainly: the electroplated nickel layer has pinholes which are the result of organic matter pollution, and the large pinholes generally indicate that the oil pollution is needed to decompose oily carbon for treatment, and the bubbles cannot be expelled due to poor stirring, so that the pinholes are formed; the occurrence of the pinholes can cause the oxidation of oxygen in the air to the workpiece along the pinholes along with the lapse of the service time, thereby losing the purpose of protecting the electroplated layer. The pinhole is characterized by small size, is difficult to observe under the condition of naked eyes, needs professional equipment for detection, causes the complexity of tool processing, also improves the cost of workpiece processing, and is not beneficial to the rapid development of the industry.

Therefore, the present inventors have aimed to invent a sealing agent for corrosion-resistant electroplated nickel layer, aiming at the above technical problems.

Disclosure of Invention

In order to overcome the above disadvantages, the present invention aims to provide a sealing agent for corrosion-resistant electroplated nickel layers.

In order to achieve the above purposes, the invention adopts the technical scheme that: a sealing agent for a corrosion-resistant electroplated nickel layer comprises a polyisocyanate monomer, polyol, nano polytetrafluoroethylene, a catalyst, a dispersing agent and an ester solvent, wherein the ester solvent is added into the polyisocyanate monomer, the catalyst, the dispersing agent and the nano polytetrafluoroethylene, the polyol is added again, the temperature is increased to 70-80 ℃, the reaction is carried out for 1-3h, and the product is cooled and stored.

Preferably, the ratio of polyisocyanate monomer to polyol is 1: 1.5-1.8. Namely, by increasing the amount of the polyol, the yield of the polyurethane synthesis is ensured.

Preferably, the catalyst is 3-5% of polyisocyanate monomer, the nano polytetrafluoroethylene is 10-15% of polyisocyanate monomer, and the dispersant is 5-8% of polyisocyanate monomer.

Preferably, at least one of caprolactam or phenol is also added dropwise during the synthesis. Ensures the stable existence of the sealing agent, and when the sealing agent is required to be used, the activation can be realized at the temperature of more than 120-150 ℃.

Preferably, the polyol is a diol or a triol, and the diol is at least one of dipropylene glycol and neopentyl glycol.

Preferably, the polyol is a polyether polyol or a polyester polyol.

Preferably, the polyisocyanate monomer comprises at least one of MDI, TDI, IPDI, HDI.

Preferably, when the polyisocyanate monomer reacts with the polyol, a stabilizer is further added, and the amount of the stabilizer is 0.5-1% of the polyol.

Preferably, the catalyst is one of dibutyltin dilaurate and organic ammonia. The application of the catalyst accelerates the reaction of polyisocyanate and polyol for producing polyurethane, and has better sealing effect on electroplated products.

The sealant for the corrosion-resistant electroplated nickel layer has the beneficial effects that the polyurethane sealant is invented, can be stably stored under normal conditions, can be activated and used in time when needed, ensures the effective use of the sealant, improves the integral use effect, and has stable combination with the nickel layer and performances of corrosion resistance, oxidation resistance and the like.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention, and to clearly and unequivocally define the scope of the present invention.

The sealing agent for the corrosion-resistant electroplated nickel layer comprises a polyisocyanate monomer, polyol, nano polytetrafluoroethylene, a catalyst, a dispersing agent and an ester solvent, wherein the ester solvent is added into the polyisocyanate monomer, the catalyst, the dispersing agent and the nano polytetrafluoroethylene, the polyol is added again, the temperature is increased to 70-80 ℃, the reaction is carried out for 1-3h, and the product is cooled and stored.

The ratio of polyisocyanate monomer to polyol is 1: 1.5-1.8. Namely, by increasing the amount of the polyol, the yield of the polyurethane synthesis is ensured.

The catalyst is 3-5% of polyisocyanate monomer, the nano polytetrafluoroethylene is 10-15% of polyisocyanate monomer, and the dispersant is 5-8% of polyisocyanate monomer.

During the synthesis, at least one of caprolactam or phenol is also added dropwise. Ensures the stable existence of the sealing agent, and when the sealing agent is required to be used, the activation can be realized at the temperature of more than 120-150 ℃.

The polyalcohol is dihydric alcohol or trihydric alcohol, and the dihydric alcohol is at least one of dipropylene glycol and neopentyl glycol.

The polyol is polyether polyol or polyester polyol.

The polyisocyanate monomer comprises at least one of MDI, TDI, IPDI and HDI.

When the polyisocyanate monomer reacts with the polyol, a stabilizer is also added, and the amount of the stabilizer is 0.5-1% of that of the polyol.

The catalyst is one of dibutyltin dilaurate and organic ammonia. The application of the catalyst accelerates the reaction of polyisocyanate and polyol for producing polyurethane, and has better sealing effect on electroplated products.

The sealant for the corrosion-resistant electroplated nickel layer has the beneficial effects that a polyurethane sealant is invented, can be stably stored under normal conditions, can be activated and used in time when needed, ensures the effective use of the sealant, improves the integral using effect, and has stable combination with the nickel layer, solves the defect of a pinhole, and has the performances of corrosion resistance, oxidation resistance and the like.

Example 1

The formula is as follows: 100 parts of diphenylmethane-4, 4' -diisocyanate, 160 parts of dipropylene glycol, 3 parts of dibutyltin dilaurate, 13 parts of nano polytetrafluoroethylene, 7 parts of a dispersing agent, 200 parts of an ester solvent and 20 parts of caprolactam.

The preparation method comprises the following steps: heating an ester solvent at 30-50 ℃, adding diphenylmethane-4, 4' -diisocyanate, keeping for 10 minutes, sequentially adding dibutyltin dilaurate, nano polytetrafluoroethylene and a dispersing agent, and keeping the temperature for 10 minutes; adding dipropylene glycol, heating to 60-80 ℃, reacting for 30 minutes, adding caprolactam, continuing to react for 30 minutes, cooling and storing.

Example 2

The formula is as follows: 100 parts of cyclohexane-1, 4-diisocyanate, 155 parts of dipropylene glycol, 3 parts of dibutyltin dilaurate, 15 parts of nano polytetrafluoroethylene, 8 parts of a dispersing agent, 200 parts of an ester solvent and 20 parts of caprolactam.

The preparation method comprises the following steps: heating an ester solvent at 30-50 ℃, adding cyclohexane-1, 4-diisocyanate, keeping for 8-10 minutes, sequentially adding dibutyltin dilaurate, nano polytetrafluoroethylene and a dispersing agent, and keeping the temperature for 10 minutes; adding dipropylene glycol, heating to 60-80 ℃, reacting for 30 minutes, adding caprolactam, continuing to react for 30 minutes, cooling and storing.

Example 3

The formula is as follows: 100 parts of toluene diisocyanate, 170 parts of neopentyl glycol, 5 parts of dibutyltin dilaurate, 12 parts of nano polytetrafluoroethylene, 8 parts of a dispersing agent, 200 parts of an ester solvent and 20 parts of phenol.

The preparation method comprises the following steps: heating an ester solvent at 30-50 ℃, adding toluene diisocyanate, keeping for 8-10 minutes, sequentially adding dibutyltin dilaurate, nano polytetrafluoroethylene and a dispersing agent, and keeping the temperature for 10 minutes; adding neopentyl glycol, heating to 80 ℃, reacting for 30 minutes, adding phenol, continuing to react for 30 minutes, cooling and storing.

The using method comprises the following steps: three pieces of electroplated nickel were taken, and washed and dried.

The samples of examples 1 to 3 were taken, heated to 130 degrees, held for 20 minutes, respectively, the work piece was immersed in the heated sample, held for 15 to 30 minutes, taken out, dried, observed and examined.

And test results are obtained, the sealing layers are attached to the surfaces of the three workpieces, the needle holes visible to naked eyes on the workpieces are completely covered by the sealing layers, and the sealing layers can exist stably, so that the effectiveness of subsequent use of the workpieces is ensured, and the service life of the workpieces is prolonged.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the present invention is not limited thereto, and any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.