KR102034466B1 - Operating Method of Satin Nickel Plating Tank With Improved Productivity - Google Patents

Abstract

The present invention relates to a method for operating a matt nickel-plating tank with a reduced defect rate and improved productivity. More specifically, a plating tank having a plating solution filled therein to plate an object comprises: a main tank (11) formed at the center of the plating tank (10), having a plating solution inlet pipe (3) and a plating solution outlet pipe (5) installed therein, and plating the object to be plated; and a side tank (12) formed at the left and right sides of the main tank (11) and having plating solution inlet pipes (2, 4) and a plating solution outlet pipe (1) installed therein. The side tank (12) comprises: a first side tank (12a) having the plating solution inlet pipe (4) installed therein; and a second side tank (12b) having the plating solution inlet pipe (2) and the plating solution outlet pipe (1). A partition (13) is formed between the main tank (11) and the side tank (12) and the height of the partition (13) is less than that of the plating tank (10).

Description

Operating Method of Satin Nickel Plating Tank With Improved Productivity

The present invention relates to a method of operating a matt nickel plating bath to lower the defective rate and improve productivity, and more particularly, in a plating bath in which a plating solution is filled to plate a plated object, the plating bath is formed in the center of the plating bath 10. A main solution 11 in which a plating liquid inflow pipe 3 and a plating liquid discharge pipe 5 are installed, and plating of the plated object is performed; And side tanks 12 formed on the left and right sides of the main tank 11 and having plating liquid inflow pipes 2 and 4 and the plating liquid discharge pipe 1 installed therein, wherein the side tanks 12 include a plating liquid inflow pipe ( 4) the first side tank 12a, the plating liquid inlet pipe 2 and the second side tank 12b in which the plating liquid discharge pipe 1 is formed, and the main tank 11 and the side tank 12 are formed. The partition 13 is formed between, the height of the partition 13 is related to the operation method of the matt nickel plating tank, characterized in that formed lower than the height of the plating bath (10).

In general, the production phase of plastic industrial products consists of receiving raw materials, injection molding, plating, painting / assembling and shipping. At this time, the plating step is a surface treatment step of coating a thin layer on the plastic surface for the purpose of improving the surface state of the material, mainly means to coat a thin layer of metal on the plastic surface. Through this, not only the corrosion resistance, wear resistance, etc. of the material can be improved, but also the gloss, texture, and the like can be given to the consumers.

Various kinds of plating methods are used for such effects, and in particular, chromium plating has been widely used as a finishing plating (final plating) of decorative plating because of its high hardness, beautiful luster, and less tendency to discolor in the atmosphere. Moreover, since it is excellent in abrasion resistance, it is widely used as hard chromium plating (industrial chromium plating) for mechanical parts, metal molds, and tools.

In addition, a method of selecting whether the chromium plating is glossy or not is used by using a glossy or matt nickel plating layer. Conventional matte or matte chromium plating of raw materials such as plastics is generally performed by chemical plating and electroplating. In contrast to electroplating, plating is performed by immersing a plating target material in a chemical plating solution through which current does not flow. The electroplating method is a method of coating the surface of a material with another metal by using precipitation due to electrolysis.

Particularly, matt nickel plating is a plating method in which a non-conductive fine particle is added to a nickel plating bath to obtain a matte surface by vacancy with nickel. When chrome plating on the matt nickel plating, microporous chromium plating is possible, thereby achieving excellent corrosion resistance. Can be. In addition, unlike bright nickel plating, a non-reflective microcrystalline nickel plating layer is formed to prevent fingerprint marks and scratches from occurring after plating.

However, the polishing agent for matt nickel plating is set to about 4 to 8 hours in use, and the plating solution must be filtered through a carbon filter to remove crystals formed from by-products. For this reason, matt nickel plating has a problem in that quality control is difficult and various defect types (white spots, black spots, unplated, flow marks, gloss deviation, etc.) are many.

Republic of Korea Patent Publication No. 10-2010-0134940 Republic of Korea Patent Publication No. 10-2010-0092311

The present invention has been made to solve the above problems, and an object of the present invention is to provide a matt nickel plating bath which lowers the defective rate of the matt nickel process and improves productivity.

In order to achieve the above object, the present invention is a plating bath 10 is filled in the plating solution 10 to plate the object to be plated, formed in the center of the plating bath 10, the plating liquid inlet pipe 3 and the plating liquid discharge pipe (5) is provided and the main article 11 which plating of a to-be-plated object is performed; And side tanks 12 formed at left and right sides of the main tank 11 and having plating liquid inflow pipes 2 and 4 and the plating liquid discharge pipe 1 installed therein, wherein the side tanks 12 include plating liquid inflow pipes ( 4) the first side tank 12a, the plating liquid inlet pipe 2 and the second side tank 12b in which the plating liquid discharge pipe 1 is formed, and the main tank 11 and the side tank 12 are formed. The partition 13 is formed between, and provides a matt nickel plating tank, characterized in that the height of the partition 13 is formed lower than the height of the plating bath (10).

At this time, the small partition 14 is formed in the side tank 12 to separate the partition, the height of the small partition 14 is preferably formed lower than the height of the partition (13).

On the other hand, the present invention is a plating bath operating method using the plating bath, by operating a plurality of plating baths, the plating bath characterized in that the plating operation is carried out continuously even when filtering the plating liquid in any one plating bath. Provide operational methods.

In the plating tank operating method, the plating liquid discharge pipe 1 and the plating liquid inlet pipe (2) when the plating operation or filter test, the main tank is preferably circulated only without the filter stirring.

In addition, when filtration of the plating liquid is performed in full, the plating liquid discharge pipes 1 and 5 and the plating liquid inlet pipes 3 and 4 are used to create a fast and strong filtration flow in the main tank 11, and to push and filter only the oil on the surface of the plating liquid. Using only the plating liquid discharge pipe 1 and the plating liquid inflow pipe 4, it is preferable that the filtration is performed only on the surface of the plating main bath.

Using the matt nickel plating bath of the present invention, it is possible to minimize the occurrence of various types of defects (white point, black point, unplated, flow marks, gloss deviation, etc.) and improve the plating productivity.

1 is an internal structural diagram of a matt nickel plating bath of the present invention.
Figure 2 is a photograph showing the anode busbar of the matt nickel plating bath of the present invention.
Figure 3 is a comparison picture showing a change in plating pattern according to the change of the anode basket length of the matt nickel plating bath of the present invention.
4A to 4D are conceptual flowcharts showing the plating liquid flow in the plating bath of the present invention. (4a: full filtration, 4b: surface filtration, 4c: plating or filter testing, 4d: night or public holidays without production)

Hereinafter, with reference to the drawings and embodiments of the present invention will be described in detail. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

Also, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in the case of conflict, the specification including definitions The description of will prevail.

Matte nickel plating bath of the present invention is a place where the electroplating of the plated, such as plastic injection molding, is formed in the center of the plating bath 10 as shown in Figure 1, the plating liquid inlet pipe (3) and the plating liquid discharge pipe (5) And a side bath 12 formed on the left and right sides of the main bath 11 and the main bath 11 where plating of the plated object is formed, and the plating liquid inflow pipes 2 and 4 and the plating liquid discharge pipe 1 are installed. do.

At this time, the side tank 12 is composed of a first side tank 12a on which the plating liquid inflow pipe 4 is installed, and a second side tank 12b on which the plating liquid inflow pipe 2 and the plating liquid discharge pipe 1 are formed. The partition wall 13 is formed between the main tank 11 and the side tank 12, and the height of the partition wall 13 is lower than the height of the plating tank 10 so that an overflow may occur.

The varnish component in the plating liquid for matt nickel plating is set at about 4 to 8 hours of use, and the plating liquid must be filtered through a carbon filter to remove crystals formed from by-products. For this reason, matt nickel plating has a problem in that quality control is difficult and there are many various types of defects.

Accordingly, the present invention is characterized in that the plating operation is continuously performed even when the plating solution in any one of the plating baths is filtered by operating a plurality of plating baths in FIG. 1.

In addition, the discharge liquid discharged from the matt nickel plating bath is filtered through at least two or more filters. Not only can the filtration effect be increased by using a plurality of filters, but a bypass valve can be installed in the piping between the filter chambers so that the filter of each filter chamber can be replaced without stopping the whole filtration process.

In this case, the inverter can be installed in the filter to adjust the filter pump speed (filtration amount) as needed, such as filtration, circulation, and flow change, and through the inverter control and bypass valve without turning off the filter, overflow circulation filtration, etc. It is possible to compensate for the problem that impurities are discharged from the carbon filter when the filter is stopped and restarted.

On the other hand, in order to lower the defective rate of the matt nickel plating bath and improve productivity, it is preferable to use an anode eastern bar lining with titanium as shown in FIG. 2. By using copper busbars lining with titanium, copper ions are dissolved in the plating solution to prevent copper impurities from flowing into the plating solution. Poor or impurity contamination can be minimized.

As shown in FIG. 2, it is preferable to install a device and a reducer that reciprocate horizontally in the cathode busbar to adjust the moving speed of the plated object. This prevents metal ion deposition from occurring in the high current part, thereby minimizing plating aggregation and thickness variation.

In addition, a pair of baskets connected to the busbar and receiving the positive electrode and the negative electrode are installed in the plating bath, and as shown in the right figure of FIG. 3, the length of the basket is shorter than the length of the plated object. desirable.

Conventionally, as shown in the left figure of Figure 3, the length of the anode basket is the same or longer than the product length, the metal ions are electrodeposited in the upper and lower portions of the product according to the flow of current, the deviation occurred in the thickness and gloss, but the present invention By making the length of the anode basket shorter than the length of the product, the plating can be dispersed in the upper and lower portions of the product without aggregation, thereby minimizing thickness and gloss variation.

Meanwhile, as shown in FIG. 1, a small bulkhead 14 is formed in the side tub 12 to separate a partition, and the height of the small bulkhead 14 is greater than that of the partition 13. It is preferably formed lower than the height. The small partition wall 14 serves to help the plating liquid to circulate well by distinguishing the inflow pipe or the outflow pipe installed in the side tank 12.

Looking at the plating tank operating method using the plating tank 10 of the present invention, first, as shown in Figure 4a, when the plating liquid is filtered through the plating liquid discharge pipe (1,5) and the plating liquid inlet pipe (3,4), It is desirable to form a fast and strong filtration stream in the main bath 11 to quickly filter the degradation material. On the other hand, when only the oil on the surface of the plating liquid is pushed out and filtered as shown in FIG. 4B, it is preferable to operate only the surface of the plating main tank using only the plating liquid discharge pipe 1 and the plating liquid inlet pipe 4.

In addition, when plating is performed, or when the filter is tested after replacing the filter filter, or when the carbon fine powder is refiltered, the plating liquid discharge pipe 1 and the plating liquid inlet pipe 2 are used as shown in FIG. 4C. It is preferable that only the filter is circulated without liquid stirring, and in order to prevent fire in case of no production or night, it is preferable to form a filtration flow in the plating bath as shown in FIG. 4D.

Looking at the plating method using the matt nickel plating bath of the present invention, the matt nickel plating method of the plated material using the plating bath of the present invention is an etching and neutralization step to increase the adhesion of the surface of the workpiece, the etching and neutralized Activation step of adsorbing a catalyst on the surface of the plating material, chemical plating step of forming a nickel layer on the surface of the workpiece to which the catalyst is adsorbed, copper to form a copper layer on the surface of the plated material on which the nickel layer is formed by electroplating A plating step, a nickel plating step of forming a nickel layer on the surface of the plated object on which the copper plating layer is formed by electroplating, a chromium plating step of forming a chromium plating layer on the surface of the plated material on which the nickel plating layer is formed through electroplating, and the The plating is performed through a washing step of removing foreign matter on the surface of the plated object. Each step is described in detail below.

First, in order to remove foreign substances, fats and oils, and the like deposited on the surface of the plated material such as plastic, which is an raw material, before performing a full surface treatment, it is preferable to first perform a degreasing process with sulfuric acid or the like.

The plated material subjected to the degreasing process is subjected to etching and neutralization processes to secure the adhesion of the plating layer. In etching process, hexavalent chromium and sulfuric acid are used to melt the surface of the plated material to form fine concavo-convex, which has an anchoring effect to improve the adhesion of the plating. Afterwards, neutralization with hydrochloric acid and hydrazine is performed to neutralize hexavalent chromium that has penetrated the surface of the plated material and rack. After the neutralization process, it is preferable to further undergo a second neutralization (pre-dip) step of secondary neutralization of hexavalent chromium remaining with hydrochloric acid.

The surface-treated plated material is subjected to an activation step of adsorbing a catalytic metal (palladium) necessary for subsequent chemical nickel plating. First, a palladium-tin catalyst is adsorbed on the surface of the plated material so that the strong tin can serve as a nucleus for adsorbing palladium metal on the surface, and then excess tin is removed to expose the palladium to the surface. At this time, be careful not to precipitate the nickel plating layer by dissolving and dropping the catalyst layer adsorbed on the rack.

In order to first conduct the surface of the plated material for the subsequent electroplating process, a nickel layer is formed on the surface of the plastic on which the catalyst is adsorbed by chemical plating. At this time, it is possible to minimize the injection failure by rapidly depositing and forming the plating layer under high temperature, high concentration conditions. In addition, it is desirable to perform two times of chemical nickel plating to improve the corrosion resistance.

When all chemical plating lines are passed as described above, the plated material is moved to the electroplating line and is subjected to the electroplating process.

First, a process of first forming a copper layer through electroplating on the surface of the plated object on which the nickel layer is formed by the chemical plating method. Copper has excellent flexibility to absorb shocks due to thermal expansion coefficient difference (7 ~ 8 times) between plastic and metal, and improves adhesion between plastic and plating layer.

Subsequently, a nickel layer is formed on the surface of the plated material on which the copper layer is formed through electroplating in order to provide corrosion resistance, chemical resistance, abrasion resistance, and a matte effect. The nickel plating process, specifically, the first nickel plating step of forming a semi-gloss nickel layer on the surface of the plated object on which the copper plating layer is formed by electroplating, the polished nickel through electroplating on the surface of the plated object on which the semi-gloss nickel layer is formed A secondary nickel plating step of forming a layer, a third nickel plating step of forming a matt nickel layer through electroplating on the surface of the workpiece to which the polished nickel layer is formed, and an electroplating on the surface of the workpiece to which the matt nickel layer is formed It is preferred to consist of a fourth nickel plating step of forming a microporous nickel layer through plating.

In detail, first, a semi-gloss nickel layer is formed through electroplating in order to increase chemical resistance through corrosion resistance and high potential formation on the surface of the plated material on which the copper plating layer is formed. This accounts for 60 to 80% of the total nickel plating layer. After the semi-gloss nickel layer is formed, a glossy nickel layer is formed through electroplating for high strength and hardness.

Then, in order to implement a semi-gloss, matte color, to form a matte nickel layer using the plating bath of the present invention on the plastic surface on which the glossy nickel layer is formed. The matt nickel layer is formed by adding non-conductive fine particles to a nickel plating solution to precipitate together, and have a matte and milky white color.

A microporous nickel layer is formed on the surface of the plated material on which the matte nickel layer is formed to improve corrosion resistance by dispersing a corrosion current. At this time, the MP nickel potential difference is 20 ~ 40mV and the fine porosity is preferably 10,000 / cm 2 or more.

As such, when the electroplating process of nickel in all four steps is performed, a chromium layer is formed as a final plating layer for decoration, corrosion resistance, and wear resistance. Subsequently, the surface of the plated material to which the plating is completed is subjected to washing and drying processes to remove foreign substances.

On the other hand, the non-conductive fine particles used in the plating liquid of the matt nickel plating bath of the present invention can be used in the non-conductive polymer particles that can be dispersed in the plating liquid and filtered through a filter.

As the polyamide particles, various commercially available polyamide particles may be used. Preferably, polyamide particles prepared by the following method may be used.

In the polyamide particles according to the preferred embodiment of the present invention, caprolactam, which is a polymerization monomer, is added to the mixed solution from which water is removed by heating after mixing the liquid paraffin and the dispersion stabilizer so as to exhibit stable dispersibility even in the plating solution. Adding potassium to the mixed solution to which the lactam is added and reacting, cooling the reaction temperature to 70 to 80 ° C., and then adding phosphorus trichloride, and raising the reaction temperature to 150 to 180 ° C. after the addition of the phosphorus trichloride, and alkali metal catalyst. It is preferable to be prepared through the; Each step is described in detail below.

First, the liquid paraffin and the dispersion stabilizer as a solvent are mixed and then heated to a temperature of 100 ° C. or higher, preferably 110 to 120 ° C. higher than the boiling point of water to remove water. In general, in the anion ring-opening reaction of lactam, water is a factor that hinders the reaction, so the moisture drying removal process is an important process in the polymerization reaction.

Caprolactam, which is a polymerization monomer, is added to the mixed solution from which the water is removed. The caprolactam has a structure of 6 carbon atoms, and when polymerized, forms a polyamide chain having 6 carbon atoms.

Thereafter, 1 to 2% by weight of an alkali metal catalyst potassium was added as a polymerization initiator catalyst and completely reacted for 30 minutes to 1 hour, and the reaction temperature was cooled to 70 to 80 ° C below the initial boiling point of the polymerization initiator. Phosphorus trichloride as a polymerization initiator is added.

After addition of phosphorus trinitrate, the reactor was slowly heated while heating to a temperature of 150-180 ° C., which is the reaction temperature of caprolactam, followed by additional heating of 0.3% by weight of potassium relative to the monomer, followed by reaction for 30 minutes to 1 hour.

At this time, the potassium introduced at the beginning of the reaction in the reaction process is for generating salt from the lactam, and additionally serves as a practical catalyst. Therefore, it is possible to increase the yield by dividing the alkali metal catalyst separately, and to obtain polyamide fine particles having a distinct spherical shape.

After the reaction was completed, the reactor was cooled to room temperature, and the obtained polyamide spherical fine particles were filtered using a filter under reduced pressure, and then the isopropyl alcohol was mixed with the filtered fine particles, stirred for 30 minutes, and then filtered under reduced pressure three times. After drying for 24 hours in a 50 ℃ oven, it is possible to obtain spherical polyamide fine particles.

On the other hand, the polyamide microparticles, in order to minimize the occurrence of aggregation between the microparticles, it is preferable to use a surface coated with a nitrogen-containing polymer once more, wherein the nitrogen-containing polymer is preferably polyethyleneimine.

Specifically, the polyamide fine particles prepared by the above-described method is added to a 10-15% by weight aqueous solution of polyethyleneimine (average molecular weight 1500-1800) and stirred at 95-100 ° C. for 2 to 3 hours, followed by coating poly The amide fines can be filtered off, washed and dried in vacuo for final use.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to specific preparation examples and examples. However, this embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

EXAMPLE

(1) First, degreasing treatment was carried out with sulfuric acid to remove oils and coatings on the surface of the plastic injection molded product, and then the surface was etched with hexavalent chromium and sulfuric acid. The hexavalent chromium that penetrated the injection surface was neutralized with hydrochloric acid and hydrazine, and then the palladium catalyst was adsorbed on the neutralized injection surface. Thereafter, a catalyst was formed on the surface of the injection-activated injection-molded metal by chemical reduction to conduct the injection-molded product.

The conductive plastic injection molded product was formed by sequentially forming a copper layer, a nickel layer, a semi-gloss nickel layer, a glossy nickel layer, a matt nickel layer, a microporous nickel layer, and a chromium layer by electroplating in a series of plating baths. The finished plastic injection molded product was washed with ionic hot water and finally drained with a centrifugal hot air dehydrator.

At this time, Example 1 was prepared using a polyamide resin (Versamid® 115, 300ppm) consisting of dimer acid and aliphatic amine as the non-conductive fine particles in the plating solution forming the matt nickel layer.

(2) Example 2 was prepared in the same manner as in Example 1 using a non-nickel plated plastic injection molding, non-conductive fine particles prepared as follows.

First, 3.75 g of potassium stearate as a dispersion stabilizer was added to 175 g of liquid paraffin as a solvent and mixed, followed by stirring at 110 ° C. higher than the boiling point of water for 1 hour. After the polymerization of the polymerization monomer caprolactam at the same temperature and 100% conversion, the solid content was added to 25% by weight, dissolved in a solvent for 1 hour and dried, and an alkali metal catalyst 0.84g was added. After 30 minutes, the mixture was cooled to a temperature of 75 ° C. under the boiling point of the polymerization initiator, and 0.5 ml of the polymerization initiator was added thereto.

Then, when the reaction temperature is reached by heating to 175 ℃, 0.3 g of alkali metal catalyst was further added to the reaction for 30 minutes to wash the solid obtained with isopropyl alcohol three times under reduced pressure filtration and dried for 24 hours at 50 ℃ oven To prepare the polyamide fine particles of Example 2.

(3) The polyamide microparticles prepared in Example 2 were added to a 10% by weight aqueous solution of polyethyleneimine (average molecular weight 1500-1800) and stirred at 100 ° C. for 3 hours, followed by filtration, washing and drying. In the same manner as in Example 1, the plastic injection molding was matte nickel plated, but Example 3 was prepared using the coated nonconductive fine particles.

Experimental Example

The homogeneity and incidence of matte plating of the plastic injection products of Examples 1 to 3 were observed and shown in the following table. (The more +, the more homogeneous)

As can be seen from the table, it was confirmed that the degree of homogeneity is improved and the failure rate is lowered to 3 in Example 1.

In the present specification, only a few examples of various embodiments performed by the present inventors are described, but the technical idea of the present invention is not limited thereto, but may be variously modified and implemented by those skilled in the art.

1,5: plating liquid discharge pipe 2,3,4: plating liquid inflow pipe
10: plating bath 11: main bath
12: side jaw 12a: first side jaw
12b: first side tank 13: partition wall
14: small bulkhead

Claims (2)

As the operation method of the plating tank 10 for plating the plated object by filling the plating liquid therein,
The plating bath 10, i) the main bath 11 is formed in the center of the plating bath 10, the plating liquid inlet pipe 3 and the plating liquid discharge pipe 5 is installed, the plating of the plated object is made; And ii) formed on the left and right sides of the main tank 11, the side tank 12, the plating liquid inlet pipe (2, 4) and the plating liquid discharge pipe 1 is installed;
The side tank 12 is composed of a first side tank 12a in which the plating liquid inflow pipe 4 is installed, and a second side tank 12b in which the plating liquid inflow pipe 2 and the plating liquid discharge pipe 1 are formed.
The partition wall 13 is formed between the main tank 11 and the side tank 12, the height of the partition wall 13 is formed lower than the height of the plating tank 10,
The plating bath 10 is a plurality of operating,
In the plating operation or the filter test, using the plating liquid discharge pipe (1) and the plating liquid inlet pipe (2), only the filter is circulated without liquid stirring,
When filtering the plating liquid as a whole, the plating liquid discharge pipes 1 and 5 and the plating liquid inlet pipes 3 and 4 are used to create a fast and strong filtration flow in the main tank 11,
A method of operating a plating bath, characterized in that only the plating liquid discharge pipe (1) and the plating liquid inlet pipe (4) are used to filter only the surface of the plating main bath when the oil is removed from the surface of the plating liquid and filtered. delete

Images