KR0136173B1 - Additives in the chloride solution for zn electroplating and the solution therewith - Google Patents

Abstract

In the present invention, electrolytic galvanizing by adding a small amount of the additive of the present invention to a conventional chloride-based galvanizing solution in the chloride bath electrogalvanizing, the crystal grains of the galvanized layer is finely uniform, the glossiness and the whiteness of the surface quality of the galvanized steel sheet. And it is an object of the present invention to provide an additive of the chloride-based electro zinc plating solution that can improve the surface roughness and a chloride-based electro zinc plating solution containing the same.

The present invention includes at least one of polyethylene glycol (H (OCH ₂ CH ₂ ) _n OH) in which the number of n is in the range of 10-20 and in the range of 20-30, and the composition weight ratio is 1: 2-1: 5 Chloride-based electrolysis, characterized in that the composition is added to the aqueous polyethylene glycol solution having a concentration of 10-15% by weight, by adding 0.1-5.0% by weight and 0.001-1.0% by weight of aromatic acid and hydrogen peroxide relative to the weight of the polyethylene glycol, respectively. It is an object of the present invention to provide an electrolytic zinc-based plating solution, characterized in that it contains an additive of zinc plating solution and 0.1-4.0 ml / l.

Description

{Name of invention}

Additives of chloride type electro zinc plating solution and plating solution containing same

{Detailed description of invention}

The present invention relates to an additive of a chloride type electro zinc plating solution and a plating solution containing the same, and more particularly, to improve surface roughness and surface gloss and whiteness of a zinc plating layer when electroplating a steel plate using a chloride bath. The present invention relates to an additive and an acid chloride plating solution containing the additive.

In general, electro-zinc plating materials have many advantages in terms of ease of plating, cost, and corrosion resistance, and are widely used as materials for home appliances, construction, automobiles, and the like. In particular, in the case of electro-galvanized steel sheet, high current density plating is essential for improving productivity, and it is often used for painting, and thus the whiteness of the plating layer should be excellent. In general, a zinc bath, a sulfate bath, and a cyan bath are used as the plating baths in electro zinc plating. Among them, the chloride bath is known to be suitable for high current density plating because of its excellent electrical conductivity. However, in the case of electrogalvanizing the steel plate using the chloride bath in this way, when the current density increases, the whiteness of the plating layer decreases and the surface becomes rough.When the phosphate treatment or coating is applied, the surface is dark, reflected on the surface, and the sensibility is poor. There is a problem.

Therefore, various methods have been proposed in order to solve the surface property deterioration, which is a problem that occurs during the electrolytic galvanizing of the chloride bath as described above, and representative methods include US Patents 4,210,500, US Patents 4,146,441, US Patents 4,049,510, and Japanese publications. Patent No. 58-48639.

US Pat. No. 4,210,500 of the conventional methods described above aims to improve glossiness in an alkali cyan bath, and US Pat. No. 4,146,441 is a mixture of formaldehyde for improving the glossiness of the plating layer in the sulfuric acid bath and increasing the range of the plating current density. US Pat. No. 4,049,510 improves the glossiness by adding an amine polymer in the chloride system. In addition, Japanese Patent Publication No. 58-48639 is a method of selectively using ammonium chloride, potassium chloride, sodium chloride, aluminum chloride, barium chloride, calcium chloride, magnesium chloride and the like and changing the plating conditions.

As described above, however, all of the methods improved only the glossiness of surface appearance characteristics, and thus there was a problem in improving whiteness.

Thus, the present inventors have conducted research and experiments to solve the conventional problems as described above to produce an electro-zinc plated steel sheet having excellent surface properties, and as a result, the present invention is proposed. The addition of a small amount of the additive of the present invention to the electrolytic zinc plating solution to electro-galvanize the crystal grains of the galvanized layer to improve the gloss, whiteness and surface roughness of the surface quality of the electro-galvanized steel sheet. It is an object of the present invention to provide an additive and a chloride type electro zinc plating solution containing the same.

Hereinafter, the present invention will be described.

The present invention relates to an additive of a chloride type electro zinc plating solution, wherein the number of n of polyethylene glycol (H (OCH ₂ CH ₂ ) _n OH) includes at least one of 10-20 and 20-30, respectively In a polyethylene glycol aqueous solution having a weight ratio of 1: 2-1: 5 and mixed at a concentration of 10-15% by weight, 0.1-5.0% by weight of aromatic acid and hydrogen peroxide, and 0.001-0.1% by weight, of the polyethylene glycol, respectively. It relates to an additive of the chloride-based electro-zinc plating solution, characterized in that by adding 1.0% by weight.

The present invention relates to a chloride type zinc oxide solution, wherein polyethylene glycol ((H (OCH ₂ CH ₂ ) _n OH) includes at least one of n in the range of 10-20 and 20-30, respectively In an aqueous polyethylene glycol solution having a concentration of 10-15% by weight so as to be 1: 2-1: 5, and 0.1-5.0% by weight and 0.001-1.0% by weight of aromatic acid and hydrogen peroxide, respectively, based on the polyethylene glycol weight. The present invention relates to a chloride type electro zinc plating solution, characterized in that it contains 0.1-4.0 ml / l of an additive of a chloride type electro zinc plating solution.

Hereinafter, the present invention will be described in more detail.

The additive of the chloride-based electro zinc plating solution of the present invention is prepared by stirring water for about 300 seconds at a temperature range of 60 ° C. at room temperature while adding water to a mixture containing polyethylene glycol and aromatic acid, and polyethylene glycol (H (OCH ₂ CH). ₂ ) _n OH), aromatic acid, hydrogen peroxide and the remaining water.

In this case, the polyethylene glycol is not only composed of at least two polymers of different n-number composition, but also n must be at least one component of 10-20 and 20-30, each of the two components at 1: 2 Mix in a ratio of 1: 5 so that the concentration is between 10 and 15% by weight, for the following reasons:

When the number of n of the polyethylene glycol is 10 or less, the effect of refining the galvanized layer grains is insignificant, and when the number of n is 30 or more, the effect of improving the whiteness of the galvanized layer is reduced, so the number of n is preferably limited to 10-30. Do.

In addition, the number of n limited to the above range is preferably limited to the mixing ratio between the components of 10 to 20 and the components of 20 to 30 in the range 1: 2-1: 5, because the mixing ratio is 1 If the ratio is less than 2, the effect of miniaturization of the grains of the galvanized layer is insignificant, and if it is greater than 1: 5, the effect of improving the whiteness of the galvanized layer is reduced. At this time, the component with many n-numbers shows a whiteness improvement function.

When the concentration of polyethylene glycol mixed at the above ratio is less than 10%, the surface of the zinc plated layer is reduced because the finer effect of the zinc plated layer crystals is less, and when the concentration of the polyethylene glycol is 15% or more, the concentration of polyethylene glycol is 10-15. Limited to% is preferred.

In addition, the aromatic acid and hydrogen peroxide are contained in an amount of 0.1 to 5.0 weight percent and 0.001 to 1.0 weight percent, respectively, based on the weight of the polyethylene glycol, for the following reason.

When the content of the aromatic acid is 0.1% by weight or less, the zinc plated layer particles are not uniform, and when 5% by weight or more, yellow stripes are generated on the zinc plated layer as well as the zinc plated state becomes poor. At this time, any of the aromatic acids may be used, or may contain one or two or more kinds.

When the content of the hydrogen peroxide is 0.001% by weight or less, there is no effect of improving the surface glossiness and whiteness, and when 1.0% by weight or more, the plating current efficiency is lowered, and the surface of the galvanized steel sheet becomes rough.

On the other hand, in the present invention, the additive of the chloride type electro zinc plating solution, which is prepared as described above, is added to a conventional chloride type electro zinc plating solution to prepare the chloride type electro zinc plating solution of the present invention. At this time, the zinc ion concentration in the conventional electrolytic zinc plating solution is 70-100g / l, the chlorine ion concentration is 230-280g / l, the pH of this plating solution is 4-5.5, the temperature is 55-65 ℃, the current density is 20 -120 A / dm ² , and relative flow rate is 1.0-2.0 m / sec.

The chloride type electro zinc plating solution of the present invention is added by adding 0.1-4.0 ml / l of the additive of the chloride type electro zinc plating solution of the present invention to a conventional zinc electroplating solution maintained under the plating solution composition and plating conditions as described above. It is preferable to manufacture because of the following.

When the content of the additive in the plating solution is 0.1ml / l or less, it is not possible to obtain the effect of improving the roughness, glossiness and whiteness of the zinc plating layer, and when it is 4.0ml / l or more, the glossiness and whiteness are lowered and the efficiency of plating current is low. It is preferable to limit the concentration to 0.1-4.0 ml / l, and more preferably 0.2-2.0 ml / l.

As mentioned above, the surface roughness and glossiness of the plated steel sheet are obtained by electroplating the steel sheet with the chloride-based electroplating solution to which the additive of the chloride-based zinc-plating solution of the present invention is added in the range of 0.1-4.0 ml / l. It is possible to obtain a plating layer having excellent whiteness, and exhibits the most excellent properties in the amount of additive addition in the range of 0.2-2.0 ml / l.

In addition, the additive of the present invention can be applied to electro zinc plating using acid chloride regardless of the metal type and shape of the plating agent, and in particular, it facilitates excellent plating quality during combustion electro zinc plating of steel sheets requiring high current density plating. It is a very effective means of getting it.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

Example 1

In order to have a composition as shown in Table 1 below, polyethylene glycol, an aromatic acid, and hydrogen peroxide were dissolved in water as a solvent, thereby preparing an additive of a chloride type electro zinc plating solution. The additive prepared as described above was added 0.1 ml / l to the chloride type electro zinc plating solution to perform electro zinc plating on the cold rolled steel sheet to measure gloss, whiteness and roughness, and the results are shown in Table 1 below.

At this time, the aromatic acid of the additive was used as benzoic acid, the plating conditions are chloride-based plating bath Zn: 90 / l, Cl: 270 g / l, zinc plating layer deposition amount: 20 g / m ² , pH: 4.5, temperature: 60 C, current density: 100 A / dm ² and flow rate: 1.2 m / sec.

In addition, glossiness and whiteness were measured by using a glossimeter and a color difference meter, and surface roughness was measured by a three-dimensional roughness meter.

* 1) In Table 1, the aromatic acid and hydrogen peroxide are weight percent based on the polyethylene glycol concentration.

2) Glossiness: Good: 20 or more, Normal: 15-20, Poor: 15 or less

3) Whiteness: L value of Color Difference Meter (good: 80 or more, normal: 75-80, poor: 75 or less)

4) Roughness: Plating roughness (Rmax)-disc roughness (Rmax) (good: 2 μm or less, normal: 2-3 μm, poor: 3 μm or more)

In the case of the invention example (2-4, 7, 8, 11, 12, 16-19, 22-25: satisfying the additive component range of the present invention as shown in Table 1 above, the gloss, whiteness and surface of the plating material While all of the roughness properties are good, the surface properties of the comparative examples (1, 5, 6, 9, 10, 13, 14, 15, 20, 21, 26) outside the scope of the present invention can be seen that the surface properties are poor. .

That is, Table 1 shows surface characteristics such as surface glossiness, whiteness, and particle roughness of the plating layer according to the molecular weight component of polyethylene glycol, and the number of n of polyethylene glycol is 10 or more, within 30 and within the range of 10-20 and 20 The ratio of those in the -30 range is within the range of 1: 2-1: 5, and the concentration is maintained at 10-15 percent, and the aromatic acid and hydrogen peroxide are 0.1-5.0 weight percent and 0.001-1.0 weight, respectively, based on the weight of the polyethylene glycol. It is shown that the surface properties of the plated steel sheet are excellent when the steel sheet is electrogalvanized using the additive of the chloride-based zinc oxide solution composed of percent.

Example 2

After cold-rolled steel sheet as a base metal, the additives were added to the chloride-based plating solution having the plating solution concentration and plating conditions as shown in Table 2 while varying the addition amount as shown in Table 2, followed by electro zinc plating, and then the gloss of the galvanized steel sheet. Degrees, whiteness and surface roughness were measured, and the results are shown in Table 2 below. At this time, the additive was used as a solution in which n number of polyethylene glycol is 15 and 25 in 1: 3, and 1.0% of aromatic benzoic acid and 0.05% of hydrogen peroxide were added.

In addition, glossiness and whiteness were measured by using a glossimeter and a color difference meter, and surface roughness was measured by a three-dimensional roughness meter.

* 1) Glossiness: Good: 20 or more, Normal 15-20, Poor 15 or less

2) Whiteness: L value of Color Difference Meter (good: above 80, normal: below 75-80 bad 75)

3) Roughness: Plating roughness (Rmax)-disc roughness (Rmax) (good: 2μm or less, usually 2-3μm, poor 3μm or more)

As shown in Table 2, the invention material (6-11) when the electroplated with a plating solution to which the additive is added in the scope of the present invention showed good surface properties such as gloss, roughness and whiteness On the other hand, in the case of the comparative material (1-5) to which the additive is added outside the scope of the present invention, it was found that the surface properties such as glossiness, roughness, and whiteness deteriorated compared to the invention material.

As described above, when the electro-zinc plating is performed using the additive of the present invention and the plating solution containing the same, there is an effect of easily producing an electro-zinc plated steel sheet having excellent gloss, whiteness and surface roughness.

Claims (2)

In the additive of the chloride-based zinc electrolytic solution, the number of n of polyethylene glycol (H (OCH ₂ CH ₂ ) _n OH) includes at least one of 10-20 and 20-30, respectively, and the composition weight ratio is 1 : 2-1: 5, and mixed with an aqueous polyethylene glycol solution having a concentration of 10-15% by weight, by adding 0.1-5.0% by weight and 0.001-1.0% by weight of aromatic acid and hydrogen peroxide to the weight of the polyethylene glycol, respectively. An additive of a chloride type electro zinc plating solution, characterized in that. In the additive of the chloride-based zinc electrolytic solution, the number of n of polyethylene glycol (H (OCH ₂ CH ₂ ) _n OH) includes at least one of 10-20 and 20-30, respectively, and the composition weight ratio is 1 : Mixed in a ratio of 2-1: 5 to an aqueous polyethylene glycol solution having a concentration of 10-15% by weight, by adding 0.1-5.0% by weight and 0.001-1.0% by weight of aromatic acid and hydrogen peroxide to the weight of polyethylene glycol, respectively. A chloride type electro zinc plating solution characterized by containing 0.1-4.0 ml / l of an additive of a chloride type electro zinc plating solution.