KR101091341B1 - Composition for steel coating and zinc or zinc-base alloy coated steel sheet - Google Patents

Abstract

The present invention is to provide a composition for coating a steel sheet excellent in adhesion, processability, weldability and alkali film removal property and zinc or zinc-based alloy plated steel sheet, comprising: a silicon compound; It provides a composition for coating a steel sheet containing a sulfur compound and a phosphorus compound.

The present invention also provides a zinc or zinc-based alloy plated steel sheet comprising a film formed by contacting the steel sheet surface with a composition for coating a steel sheet containing a silicon compound, a sulfur compound and a phosphorus compound.

Adhesive, Mineral, Organic Acid, Phosphate, Friction Coefficient, Zinc Plating

Description

COMPOSITION FOR STEEL COATING AND ZINC OR ZINC-BASE ALLOY COATED STEEL SHEET}

The present invention relates to a zinc or zinc-based alloy plated steel sheet having a composition for coating a steel sheet and a film formed thereby. More specifically, the present invention relates to a steel sheet coating composition for forming a coating film excellent in workability, adhesion, weldability and alkali film removal property, and a zinc and zinc-based alloy plated steel sheet having a film formed thereby.

Zinc or zinc-based alloy plated steel sheet has a beautiful surface appearance, excellent ability to protect the steel sheet in terms of corrosion resistance, inexpensive and easy to manufacture has been widely used as automotive steel sheet. However, since zinc or zinc-based alloy plated steel sheet is rough and soft, the steel sheet itself cracks due to high frictional load when press-plating the plated steel plate because the contact area with the die is wide and easy to adhere during processing. . This will act as a factor in reducing productivity and workability in the automobile manufacturing process.

In addition, in the automobile company, the steel sheet is press-molded to a desired shape, followed by degreasing and chemical conversion, followed by electrodeposition coating. Since zinc or zinc-based alloy-plated steel sheet has a base layer compared to iron, crystal grains are formed during chemical conversion. This coarse coarse hopitite crystal is formed, which makes it easy to form electrodeposition coating defects such as pinholes during electrodeposition coating. Therefore, it is disadvantageous in terms of corrosion resistance after painting.

On the other hand, in the case of steel sheet for automobiles, various adhesives are used to bond the inner and outer plates, which prevents noise while driving the body, improves the dent resistance of the outer plates, and penetrates contaminants such as water or salt into the hamming part. It protects the car body from corrosion by preventing it. Therefore, if there is a component that adversely affects the adhesion of the foreign matter or adhesive on the surface of the steel sheet may increase the noise of the car, as well as cause serious problems in stability in long-term use.

In order to improve the above problems of zinc or zinc-based alloy coated steel sheet, 95% by weight of iron or phosphorous on alloyed hot-dip galvanized steel sheet (hereinafter referred to as "GA steel sheet") or zinc-iron (nickel) alloy electroplated steel sheet Flash with thin plating of alloys such as iron-zinc (Fe-Zn), iron-manganese (Fe-Mn) or phosphorus-iron (P-Fe) by 3000 ~ 5000mg / m ² by electroplating Steel plate was developed. However, since the production cost of such flash steel sheet is high, automakers have stopped using it in terms of cost reduction.

In addition, another method for solving the problems of the zinc or zinc-based alloy plated steel sheet has been proposed a method of improving the workability and adhesion by coating a resin on the plating layer or by performing an inorganic phosphate treatment. However, in the case of the resin coating, since the melting point is very low and there is no conductivity, the scar marks of the electrode remain as they are, and thus are transferred to defects.

On the other hand, inorganic phosphate treatment has been shown to have some effect on improving workability and lubricity, but since phosphoric acid is a weak acid, it is impossible to reduce the free acid in a solution more than a certain limit, and thus a large amount of free phosphoric acid remains in the coating. This has a disadvantage in that the adhesion to the adhesive is inferior because it degrades the adhesion with the adhesive. In addition, the inorganic phosphate coating mainly consists of a polymer form of insoluble condensed zinc phosphate, and as a result, it is difficult to dissolve in an alkali degreasing solution or an acidic zinc phosphate treating solution in the chemical conversion treatment process, resulting in poor chemical conversion treatment and thus coating. It also has the problem that adhesiveness and corrosion resistance after painting fall.

Therefore, in order to solve this problem of the inorganic phosphate coating, a method of forming an inorganic phosphate coating in two layers has been proposed. In this method, a dense film in the form of a polymer of insoluble condensed zinc phosphate is formed on the upper layer, and a crystalline film structure in the form of a soluble zinc phosphate is formed on the lower layer. Thus, when the inorganic phosphate film is formed in two layers, The chemical conversion treatment can be improved to some extent. However, such a two-layer coating has to be subjected to a double coating treatment, there is a problem that the temperature or other operating conditions are difficult.

The present invention is to solve the above problems, in one aspect provides a composition for coating a steel sheet that can form a coating film excellent in adhesion, processability, weldability and alkali film removal properties.

In addition, another object of the present invention is to provide a zinc and zinc-based alloy plated steel sheet excellent in adhesion, processability, weldability and alkali film removal properties produced using the steel sheet coating composition.

To this end, the present invention provides a composition for coating a steel sheet including a silicon compound, a sulfur compound, and a phosphorus compound.

In this case, the steel sheet coating composition may further include one or more selected from the group consisting of polyethylene glycol and titanium compounds.

On the other hand, in the steel sheet coating composition, the silicon compound is 1 to 5 parts by weight, the sulfur compound is 1 to 5 parts by weight, the phosphorus compound is preferably contained in an amount of 0.5 to 4 parts by weight.

In addition, the polyethylene glycol is 0.5 to 5 parts by weight, the titanium compound is preferably included in an amount of 1 to 6 parts by weight.

In addition, the steel sheet coating composition may further include one or more selected from the group consisting of vanadium compound, molybdenum compound, nickel compound, zinc compound and manganese compound, but is not limited thereto, the vanadium compound is 0.2 To 3 parts by weight, the molybdenum compound is 0.2 to 2.5 parts by weight, the nickel compound is 0.2 to 2.5 parts by weight, the zinc compound is 0.5 to 3 parts by weight, and the manganese compound is preferably added in an amount of about 0.5 to 3 parts by weight. .

In the present invention as described above, the composition for coating a steel sheet preferably has a pH of 1.5 to 6.5.

At this time, the silicon compound is an organic compound or an inorganic compound containing a silicon element, may be a colloidal silica, a silane compound or a combination thereof, more preferably a group consisting of colloidal silica, silane coupling agent, silicone resin and silicon It may be one or more selected from.

On the other hand, the sulfur compound is an organic or inorganic compound containing a sulfur element, preferably a sulfonate compound, more preferably an aryl sulfonic acid compound, most preferably a phenol sulfonic acid compound.

In addition, the phosphorus compound is an organic or inorganic compound containing phosphorus, preferably a phosphonate (or phosphonic acid) compound, a phosphate compound or a combination thereof, more preferably, hydroxyethylene depot It may be at least one selected from the group consisting of spanic acid, aminotrimethylenephosphonic acid, methylenephosphonic acid, orthophosphate and pyrophosphate.

On the other hand, the titanium compound is an organic or inorganic compound containing a titanium element, preferably one or more selected from the group consisting of a titanium coupling agent, titanium chloride, titanium dioxide, more preferably triethanolamine titanium, At least one titanium coupling agent selected from the group consisting of lactic acid titanium and isopropyl titanium.

In another aspect, the present invention also provides a zinc or zinc-based alloy plated steel sheet in which a film including silicon, phosphorus, and sulfur is formed on the surface of the steel sheet on the basis of each element.

In this case, the coating may further include titanium, and if necessary, may further include a compound including one or more elements selected from the group consisting of vanadium, molybdenum, nickel, zinc, and manganese.

On the other hand, the film of the present invention is characterized in that the film is removed by an alkali degreasing solution.

In another aspect, the present invention provides a zinc or zinc-based alloy plated steel sheet comprising a film formed by contacting the steel sheet surface with a composition for coating a steel sheet including a silicon compound, a sulfur compound, and a phosphorus compound.

In this case, the steel sheet coating composition may further include one or more selected from the group consisting of polyethylene glycol and a titanium compound.

The zinc or zinc-based alloy plated steel sheet having a lubricating film formed by the composition for coating a steel sheet of the present invention is excellent in all of lubricity, processability, adhesion, and alkali film removal property.

The zinc or zinc-based alloy coated steel sheet having the lubricating film of the present invention exhibits very good adhesion to various adhesives used in automobile bodies, and exhibits adhesive suitability equal to or higher than that of an untreated material even in a pre-cure state. . Therefore, it is very suitable as a lubricating coating material, such as GA steel plate especially used for automobiles.

In addition, since the lubricating film formed on the zinc or zinc-based alloy plated steel sheet of the present invention is removed by an alkali degreasing solution used in the degreasing process, there is no need to perform a separate process for removing the film, and excellent chemical treatment property Indicates.

In addition, the coating composition of the present invention does not acidify the solution or change the physical properties of the alkali solution even if dissolved in the alkaline solution in the degreasing process.

In addition, the coating composition of the present invention contains a component that improves dispersibility and a chelate (chelate) material so that the film-deposited coating component is ionized in the alkali degreasing solution to prevent precipitation or sludge. Therefore, the problem of steel plate contamination caused by re-adhesion of the coating component removed by the alkali degreasing solution to the surface of the steel sheet does not occur.

In addition, the coating composition of the present invention does not contain harmful substances such as Pb, Hg, Cu, Cd, As, and other heavy metal materials are environmentally friendly.

Hereinafter, the present invention will be described more specifically.

First, the composition for steel plate coating of this invention is demonstrated.

The steel sheet coating composition of the present invention is characterized in that it contains a silicon compound, a sulfonic acid containing a sulfur compound and a phosphorus compound.

The silicone compound is for improving processability and adhesion, and examples of the silicone compound usable in the present invention include colloidal silica, silane compounds, and silicones, and more preferably colloidal silica and silane coupling agents. , Silicone resin, silicone, and the like. In addition to the above compounds, various silicone compounds may be applied in a range that does not significantly deteriorate the physical properties of the coating composition of the present invention.

On the other hand, in the composition for coating a steel sheet of the present invention, the content of the silicon compound is not limited thereto, but is preferably about 1 to 5 parts by weight. If the silicone compound is added in less than 1 part by weight, the adhesion cannot be improved, and if it exceeds 5 parts by weight, a precipitate is formed and it is uneconomical.

The sulfur compound is for improving adhesion, and examples of the sulfur compound usable in the present invention may be a compound including sulfonate (RSO ₃ −), wherein R is alkyl or aryl, more preferably. Aryl sulfonic acid compounds, most preferably phenol sulfonic acid compounds.

In this case, the alkyl refers to branched or straight hydrocarbon, and is not limited thereto, and includes, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and the like.

In addition, the aryl refers to a monocyclic (monocyclic), bicyclic (bicyclic) or polycyclic (tricyclic) aromatic hydrocarbon, but is not limited thereto, for example, phenyl, biphenyl, Naphthyl, anthracenyl, phenanthrenyl, fluorenyl, indenyl, pentarenyl, and the like.

On the other hand, in the composition for coating a steel sheet of the present invention, the content of the sulfur compound is not limited thereto, but is preferably about 1 to 5 parts by weight. When the content of the sulfur compound is less than 1 part by weight, the effect of improving the adhesion is insignificant, and when the content of the sulfur compound is more than 5 parts by weight, the pH of the solution is lowered, resulting in damage to the basic physical properties of the coating composition.

The phosphorus compound is for improving processability and stability of the coating composition. Examples of the phosphorus compound usable in the present invention include a phosphonate compound, a phosphate compound, or a combination thereof, more preferably hydroxyethylenediphosphonic acid. , Aminotrimethylenephosphonic acid, methylenephosphonic acid, orthophosphate, pyrophosphate, and the like, and most preferably hydroxyethylenediphosphonic acid, aminotrimethylenephosphonic acid, and the like. In addition to the above compounds, various phosphorus compounds may be applied in a range that does not significantly deteriorate the physical properties of the coating composition of the present invention.

On the other hand, the content of the phosphorus compound is not limited thereto, but is preferably about 0.5 to 4 parts by weight. If the phosphorus compound is added in less than 0.5 parts by weight the pH of the coating composition may be increased to form a precipitate, and if more than 4 parts by weight may impair the physical properties of the solution, it may cause stains on the surface of the steel sheet.

In addition, the steel sheet coating composition of the present invention may further include a polyethylene glycol and / or a titanium compound.

When polyethylene glycol is further added to the composition for coating a steel sheet, lubricity and adhesion are further improved. At this time, the content of the polyethylene glycol is not limited thereto, but is preferably about 0.5 to 5 parts by weight. When the content of polyethylene glycol is less than 0.5 parts by weight, it is difficult to obtain additional lubricity and adhesion improvement effects, and when it exceeds 5 parts by weight, foaming amount increases in the coating composition, and precipitates are easily formed, thereby improving stability of the coating composition. There is a risk of harm.

The titanium compound is for further improving workability and adhesion, and examples of the titanium compound usable in the present invention include a titanium coupling agent, titanium chloride and titanium dioxide, and more preferably triethanolamine-based titanium. And at least one titanium coupling agent selected from the group consisting of lactic acid titanium and isopropyl titanium. In addition to the titanium compound described above, various titanium compounds may be applied in a range that does not significantly deteriorate the physical properties of the coating composition of the present invention.

On the other hand, the addition amount of the titanium compound is not limited thereto, but is preferably about 1 to 6 parts by weight. If the titanium compound content is less than 1 part by weight, it is difficult to obtain additional workability and adhesion improvement effect, and if it exceeds 6 parts by weight, it is uneconomical because there is no additional workability and adhesion improvement effect.

In addition to the above components, a vanadium compound, a molybdenum compound, a nickel compound, a zinc compound, or a manganese compound may be further added to the coating composition of the present invention as needed.

In this case, the vanadium compound is to improve processability and stability of the coating solution, and specific examples of the vanadium compound usable in the present invention include ammonium vanadium, sodium metavanadium, sodium orvanavanadium, ammonium vanadium, sodium meta, and the like. Vanadium is particularly preferred. However, in addition to the above compounds, various vanadium-containing compounds may be used within a range that does not impair the physical properties of the coating composition of the present invention. In addition, although the addition amount of a vanadium compound is not restrict | limited by this, It is preferable that it is about 0.2-3 weight part. When the addition amount is less than 0.2, further improvement effects such as workability cannot be described, and when it exceeds 3 parts by weight, it is uneconomical.

The molybdenum compound is for improving lubricity and processability, examples of the molybdenum compound usable in the present invention include ammonium molybdate, sodium molybdate and the like, ammonium molybdate is particularly preferred. However, in addition to the above compounds, various molybdenum-containing compounds may be used within a range that does not impair the physical properties of the coating composition of the present invention. In addition, the addition amount is although it does not restrict | limit, It is preferable that it is about 0.2-2.5 weight part. When the molybdenum compound is added in an amount of 0.2 parts by weight or less, it is not expected to improve workability, and when it is added in an amount of 2.5 parts by weight or more, there is no further workability improvement effect and it is uneconomical.

The nickel compound is for improving workability and adhesion, and examples of the nickel compound usable in the present invention include nickel acetate, nickel carbonate, nickel sulfate, nickel chloride and the like, and nickel carbonate is particularly preferable. However, in addition to the above compounds, various nickel compounds may be used within a range that does not impair the physical properties of the coating composition of the present invention. On the other hand, the addition amount of the nickel compound is not limited thereto, but is preferably about 0.2 to 2.5 parts by weight. If the nickel compound is added in less than 0.2 parts by weight, the processability and adhesion cannot be improved, and when the nickel compound is added in excess of 2.5 parts by weight, there is no further workability and adhesion improving effect and it is uneconomical.

The zinc compound is for improving workability and surface whiteness, and specific examples of the zinc compound usable in the present invention include zinc acetate, zinc oxide, zinc sulfate, and zinc chloride.

On the other hand, the addition amount of the zinc compound is not limited thereto, but is preferably about 0.5 to 3 parts by weight. If the zinc compound is added in less than 0.5 parts by weight can not be expected to improve the processability and whiteness, when the zinc compound is added in excess of 3 parts by weight results in poor workability.

The manganese compound is for improving processability, and specific examples of manganese compounds usable in the present invention include manganese acetate, manganese sulfate, manganese dioxide, and manganese carbonate.

On the other hand, the amount of the manganese compound added is preferably about 0.5 to 3 parts by weight. If the manganese compound is added in less than 0.5 parts by weight can not be expected to improve the workability, when added in excess of 3 parts by weight darkened the surface and there is no further workability improvement effect and is uneconomical.

In addition to the above components, the coating composition may use a surfactant, a leveling agent or a wetting agent to improve the smoothness of the coating, and may further include an ammonium solution or the like for adjusting the pH.

The present inventors have found that the properties of the steel sheet coating composition vary in stability in solution state, adhesion after formation of the coating, chemical conversion, surface appearance, and the like. For example, when the pH of the coating composition is less than 1.5, the reactivity between the solution and the GA plating layer is increased to increase the adhesion of the film, so that it is difficult to dissolve the film in the alkali degreasing process, resulting in deterioration of the alkali film removal property, and also the surface color of the coating. Appear black On the other hand, when the pH of the coating composition is high, the alkali film removal property is improved, but the adhesion is lowered, and a problem arises in the stability of the coating solution.

Therefore, in consideration of adhesiveness, stability in solution, alkali film removal property, and the like, the coating composition of the present invention preferably has a pH of about 1.5 to 6.5. If the pH is less than 1.5, the adhesiveness of the film is improved, but the lubricity deteriorates, and the surface condition is black. In addition, when the pH exceeds 6.5, the film surface appearance state is good, but the film is not formed well, the properties such as adhesion is deteriorated, it is not possible to ensure the stability of the coating composition solution.

On the other hand, in the case of the present invention, by adding an alkaline solution such as ammonia solution (ammonia solution) or sodium hydroxide to the coating composition, the pH can be adjusted to the above range, that is, 1.5 to 6.5. Although the kind of alkaline solution used for pH adjustment is not specifically limited, It is more preferable to use ammonia water etc. which do not leave a cation.

On the other hand, the steel sheet coating composition may be prepared by dissolving the above components in a solvent such as water, wherein the content of the solvent can be appropriately adjusted in consideration of the viscosity of the coating composition, etc., and is not particularly limited. .

Next, the zinc or zinc-based alloy plated steel sheet of the present invention will be described.

The zinc or zinc-based alloy plated steel sheet refers to a steel plate having a zinc plated layer or a zinc-based alloy plated layer, and specific examples thereof include a hot dip galvanized steel sheet, an electrogalvanized steel sheet, and a zinc-based alloy plated steel sheet.

Examples of the zinc-based alloy plated steel sheets include zinc-iron (cobalt and nickel) alloy electroplated steel sheets, zinc-aluminum alloy plated steel sheets, zinc-magnesium alloy plated steel sheets, and alloyed hot dip galvanized steel sheets (GA steel sheets).

On the other hand, the zinc or zinc-based alloy plated steel sheet of the present invention comprises a film formed by contacting the steel sheet surface composition of the steel sheet coating composition of the present invention, that is, a steel sheet coating composition comprising a silicon compound, a sulfur compound and a phosphorus compound It is characterized by.

At this time, the composition for coating the steel sheet is made of one or more selected from the group consisting of polyethylene glycol and titanium compounds and / or vanadium compounds, molybdenum compounds, nickel compounds, zinc compounds and manganese compounds, as necessary, It may further comprise one or more selected from the group.

At this time, specific examples and preferred contents of each component included in the steel sheet coating composition are the same as described above.

On the other hand, the method of contacting the steel sheet coating composition to the surface of the steel sheet is not particularly limited, various methods used to form a film on the steel sheet in the art, for example, coating method, dipping method, roll coating Law, electroplating, or the like.

On the other hand, the film formed using the coating composition of the present invention as described above contains a silicon, phosphorus and sulfur components. In addition, the steel sheet coating film of the present invention may further include titanium, vanadium, molybdenum, nickel, zinc or manganese, if necessary.

At this time, the coating amount of the coating is not limited thereto, but is preferably about 10 to 1000 mg / m ² . If the coating amount is less than 10 mg / m ² , workability, adhesiveness, etc. cannot be improved, and if the coating amount is more than 1000 mg / m ² , the weldability and alkali film removal property are impaired and uneconomical.

In particular, the thickness of the coating is preferably 10 mg / m ² to 500 mg / m ² , more preferably about 10 mg / m ² to 200 mg / m ² , but if the thickness of the coating is thin, the film may have a reduced conductivity. This is because weldability is excellent because there is no problem.

On the other hand, the adhesion amount of each component included in the film is silicon 1 ~ 200mg / m ² , phosphorus 1 ~ 100mg / m ² _, sulfur 0.5 ~ 100mg / m ² , titanium 1 ~ 200 mg / m ² , vanadium 0.1 ~ 20mg / It is preferable that it is about m <^2> , molybdenum 0.1-20 mg / m <^2> , nickel 0.1-20 mg / m <^2> , zinc 0.1-50 mg / m <^2> , and manganese 0.1-50 mg / m <^2> .

The film of the present invention is composed of materials that have a lubricity of the film itself, so that the film slips well and has an effect of suppressing the phenomenon of heat adhesion by preventing the film from directly contacting the plating layer and the die during press molding. In addition, the oil is retained in the very fine pores present in the coating layer, but when the pressing force is applied, the oil comes out, so the slipperiness is improved, thereby showing excellent workability. Thus, the coating acts as a lubricating coating during press molding.

In addition, the coating is an organic and inorganic composite coating in which an inorganic component such as titanium, silicon, phosphorus, sulfur and organic components included in sulfonic acid, polyethylene glycol, coupling agent, etc. are combined in a complex form, and are processed, adhesively weldable, and alkaline. It shows excellent performance in film removal properties.

The reason why the coating exhibits excellent adhesion is not fully understood, but it is presumed that the inorganic components in the coating form a dense surface structure by strongly bonding with the organic component and increase the chemical affinity with the adhesive at the interface.

On the other hand, in the case of the lubricating film formed by the coating composition of the present invention, the lubricating film of the present invention is slightly acidic, and is neutralized when reacted with an alkaline solution to increase solubility, thereby removing the film from the alkali solution used in the degreasing process. Has the property of becoming. .

In addition, since the coating composition of the present invention is a weakly acidic to neutral solution, the lubricating film of the present invention formed by applying and drying it is in the form of a neutral salt. Therefore, even when dissolved in the alkaline solution in the degreasing step, the solution is not acidified or the physical properties of the alkaline solution are not changed, so that no load is applied to the degreasing step.

In addition, the phosphorus compound of the coating composition of the present invention improves the dispersibility of the film-deposited film components, and suppresses the reactivity of metal ions, so that the film-deposited film components are not ionized to precipitate or sludge. As a result, the film removal component in alkaline solution can be re-adhered to the steel plate surface, and contamination can be prevented.

On the other hand, the coating of the present invention is excellent in weldability due to the conductivity of the inorganic material coming from the metal salt in addition to Ti and Si in the coating.

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

Example 1

The components shown in Table 1 were dissolved in water to prepare a composition for coating a steel sheet. At this time, phosphonate and phenolsulfonic acid were first dissolved in water, and the remaining components were dissolved.

[Table 1]

Composition Amount (g / L) 1) Silane coupling agent 30 2) phosphonates 30 3) phenolsulfonic acid 25 4) zinc acetate 10 5) Ammonium Molybdate 5

The steel sheet coating composition prepared as described above was uniformly coated on an alloyed hot dip galvanized steel sheet having a thickness of alkali degreasing using a bar coater # 3, and then heated at a temperature of 340 ° C. in a hot air drying furnace for 5 seconds. Dry to form a coating.

Example 2

The components shown in Table 2 were dissolved in water to prepare a composition for coating a steel sheet. At this time, phosphonate and phenolsulfonic acid were first dissolved in water, and the remaining components were dissolved.

TABLE 2

Composition Amount (g / L) 1) Titanium Coupling Agent 20 2) silane coupling agent 50 3) polyethylene glycol 10 4) phosphonates 10 5) phenolsulfonic acid 5 6) Ammonium Vanadium 5 7) Ammonium Molybdate 5

The steel sheet coating composition prepared as described above was uniformly coated on a 0.7 mm thick alloyed hot dip galvanized steel sheet, each of which was alkali degreased using a bar coater # 3, and then, in a hot air drying furnace at 340 ° C. for 5 seconds. It dried and formed the film.

Example 3

The components shown in Table 3 were dissolved in water to prepare a composition for coating a steel sheet. At this time, phosphonate and phenolsulfonic acid were first dissolved in water, and the remaining components were dissolved.

[Table 3]

Composition Amount (g / L) 1) Titanium Coupling Agent 30 2) colloidal silica 30 3) polyethylene glycol 20 4) phosphonates 20 5) phenolsulfonic acid 20 6) Ammonium Molybdate 3 7) Nickel Carbonate 5

The steel sheet coating composition prepared as described above was uniformly coated on a 0.7 mm thick alloyed hot dip galvanized steel sheet, each of which was alkali degreased using a bar coater # 3, and then, in a hot air drying furnace at 340 ° C. for 5 seconds. It dried and formed the film.

Example 4

The components shown in Table 4 were dissolved in water to prepare a composition for coating a steel sheet. At this time, phosphonate and phenolsulfonic acid were first dissolved in water, and the remaining components were dissolved.

 [Table 4]

Composition Amount (g / L) 1) Titanium Coupling Agent 20 2) silane coupling agent 25 3) polyethylene glycol 20 4) phosphonates 30 5) phenolsulfonic acid 20 6) Nickel Carbonate 10

The steel sheet coating composition prepared as described above was uniformly coated on a 0.7 mm thick alloyed hot dip galvanized steel sheet, each alkali degreased using a bar coater # 3, and then heated for 5 seconds in a hot air drying furnace at 340 ° C. It dried and formed the film.

Comparative Example 1

The components shown in Table 5 were dissolved in water to prepare a composition for coating a steel sheet. At this time the phosphonate was first dissolved in water and the remaining components were dissolved.

 TABLE 5

Composition Amount (g / L) 1) Titanium Coupling Agent 20 2) silane coupling agent 25 3) polyethylene glycol 20 4) phosphonates 30 5) Manganese Acetate 10

The steel sheet coating composition prepared as described above was uniformly coated on a 0.7 mm thick alloyed hot dip galvanized steel sheet, each of which was alkali degreased using a bar coater # 3, and then, in a hot air drying furnace at 340 ° C. for 5 seconds. It dried and formed the film.

Comparative Example 2

The components shown in Table 6 were dissolved in water to prepare a composition for coating a steel sheet. At this time, phosphonate and phenolsulfonic acid were first dissolved in water, and the remaining components were dissolved.

 TABLE 6

Composition Amount (g / L) 1) polyethylene glycol 20 2) phosphonates 30 3) phenolsulfonic acid 20 4) Ammonium Vanadium 10 5) Manganese Acetate 5

The steel sheet coating composition prepared as described above was uniformly coated on a 0.7 mm thick alloyed hot dip galvanized steel sheet, each of which was alkali degreased using a bar coater # 3, and then, in a hot air drying furnace at 340 ° C. for 5 seconds. It dried and formed the film.

Experimental Example 1: Workability

1) coefficient of friction

Applying P-DBH cleaning oil on the steel sheet film prepared by Examples 1 to 3 and Comparative Examples, sliding at a speed of 1000mm / min with a pressing pressure of 650kgf, the drawing load is applied The coefficient of friction was found by dividing by.

2) Cup Machinability

After cutting the steel sheet prepared by Examples 1 to 4 and Comparative Examples into a 100mm diameter specimen, apply a cleaning oil (PDBH) on it, and push a 50mm diameter punch at a speed of 100mm / min The maximum drawing force and limit drawing force on the specimen were measured while raising. BHF (blank holding force) was 2 tons at the maximum load measurement.

The experimental results are shown in the following [Table 7].

TABLE 7

division Coefficient of friction (m) Cup Machinability (Ton) Drawing load Molding limit load Example 1 0.155 5.4 2.5 Example 2 0.154 5.3 2.7 Example 3 0.152 5.2 3.1 Example 4 0.155 5.4 2.8 Comparative Example 1 0.167 5.9 1.5 Comparative Example 2 0.168 6.3 1.4

As can be seen from Table 7, in Examples 1 to 4 of the present invention, the friction coefficient value is 0.155 or less, whereas Comparative Examples 1 and 2 are both 0.165 or more, which is an example of the present invention. It can be seen that the case of 1 to 4 is excellent in lubricity.

In addition, in cup workability, Examples 1 to 4 show a small load applied to the specimen when the maximum drawing load is 5.5 tons or less, but Comparative Examples 1 and 2 have a high resistance of 5.9 tons or more. In addition, the molding limit load Examples 1 to 4 can be molded even in BHF of 2 tons or more, but it can be seen that all of the comparative examples can be molded only in BHF of 2 tons or less. As described above, when the composition for coating a steel sheet of the present invention is used, both the coefficient of friction and the cup workability are excellent, and the workability is very good.

Experimental Example 2: Adhesiveness

For the evaluation of adhesion, after cutting the steel sheet prepared by Examples 1 to 4 and Comparative Examples to a size of 25X120mm, only 20mm end of the specimen in the longitudinal direction is immersed in antirust oil (BW-90EG, Bumwoo Co., Ltd.) After taking it out and standing upside down in an upright position. Then, the mastic (Bowang, Metal Sealer) adhesive was applied to the end of the specimen 25X25mm area with the rust-prevented oil to a thickness of 3mm and then placed in an oven and cured at 160 ^o C for 20 minutes. After the cured specimens were left again for one day, the tensile test was performed at a rate of 50 mm / min in a tensile tester, the shear strength value was recorded, and the fracture surface of the adhesive was observed.

The fracture surface observation results are shown in the following [Table 8].

[Table 8]

division Coagulation Failure Rate (%) Shear strength (kgf / cm ² ) Example 1 100 9.1 Example 2 100 10.2 Example 3 100 9.7 Example 4 100 9.8 Comparative Example 1 92 6.5 Comparative Example 2 96 7.2

As shown in Table 8, in Examples 1 to 4, the cohesive failure rate is 100%, and the shear strength is 8 kgf / cm ² or more. On the contrary, in Comparative Examples 1 and 2, both the cohesive failure rate and the shear strength were lower than those of Examples 1 to 4, indicating poor adhesion.

Experimental Example 3: Weldability

Weldability was measured by continuous RBI and proper welding current range. For the steel sheets prepared in Examples 1 to 4 and Comparative Examples 1 and 2, welding was carried out at 12 cycles of welding time using an electrode pressure of 2.3 KN and an electrode shape of a dome shape having a tip diameter of 6 mm. Increasing the welding current from 8.4KA to 11.8KA in 0.2KA increments, the welding fracture surface was selected as the lower limit current when the plug fracture started to occur, and the current minus 0.2KA from the current where the spatter began to occur was the upper limit current. decided. Continuous RBI was determined by measuring the button size and nugget size at every 100 RBIs.

The experimental results are shown in [Table 9].

TABLE 9

division Weldable Current Range Continuous RBI Lower limit current Capping current Example 1 9.3KA 11.5KA More than 2600 strokes Example 2 9.2KA 11.4KA More than 2600 strokes Example 3 10KA 11.6KA More than 2,600 strokes Example 4 9.5KA 11.2KA More than 2600 strokes Comparative Example 1 10.6KA 11.2KA 2000 strokes Comparative Example 2 10.2KA 11.1KA 2000 strokes

As shown in Table 9, the steel sheets produced by Examples 1 to 4 had a wider weldable current range and a higher continuous RBI compared to the steel sheets prepared by Comparative Examples 1 and 2, indicating excellent weldability. Could.

Experimental Example 4 Alkali Membrane

To evaluate alkali film removal property, dissolve the 3% of 4292L-A and 0.3% of 4292L-B (Samyang Chemical), alkali degreasing solutions used by H Motor in Korea, in distilled water and make the total solution amount to 3 liters. The solution temperature was maintained at 50 ° C., and the steel bars prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were dipped for 2 minutes while rotating the magnetic bar in the solution at 500 rpm.

Then, the film removal rate was evaluated by dissolving the steel plate film with a diameter of 60 mm and quantitatively analyzing the amount of P present in the film by ICP (Inductively coupled plasma). For comparison, the amount of P present in the film of the steel sheets before immersion was quantitatively analyzed in the same manner.

It was found that about 30 mg / m ² of P was present in the coating of all steel sheets in the steel sheet before being immersed in the alkaline degreasing solution. On the other hand, in the steel sheets of Examples 1 to 4, P was not detected at all after being immersed in the alkali degreasing solution. In the case of Comparative Examples 1 and 2, the amount of P was 6, 7.5 mg / even after the alkali degreasing solution was immersed. It was understood that film removal was inferior by m ² detection.

Experimental Example 5: Chemical Treatment

Specimens were prepared by cutting the steel sheets prepared by Examples 1 to 4 and Comparative Examples 1 and 2 to 75 × 150 mm. Subsequently, it was immersed in 0.1 liter solution of 3 liters of room temperature surface adjuster (PZ, Samyang Chemical) for 1 minute and then taken out. Immediately, 50% of phosphate solution (Gardobond 699, Samyang Chemical) 6% (1 point of free acidity, acidity) 20 points) was immersed for 2 minutes, washed with water and dried to form a chemically treated film.

The chemical conversion coating is evaluated to be excellent when the grain size is 15 microns or less and the adhesion amount is in the range of 3 to 5 g / m ² . In the case of the steel sheets of Examples 1 to 4, all the crystal grains of the chemical conversion coating were 15 microns or less, and the adhesion amount was 3.5 to 4.5 g / m ² . On the contrary, in Comparative Examples 1 and 2, the grain size of the chemically treated film was 16.4 and 17.5 microns, respectively, and the film formation state was uneven, and the film adhesion amount was 5.3 and 5.1 g / m ² , respectively.

Claims (19)

Silicone compounds; Sulfur compounds; And A composition for forming a lubricating film comprising a phosphorus compound and forming a lubricating film having excellent film removal property with respect to an alkali degreasing solution. The method of claim 1, The lubricating film-forming composition is a lubricating film-forming composition further comprises one or more selected from the group consisting of polyethylene glycol and titanium compounds. The method of claim 1, The silicon compound is 1 to 5 parts by weight, The sulfur compound is 1 to 5 parts by weight, The phosphorus compound is a composition for forming a lubricant film contained in an amount of 0.5 to 4 parts by weight. 3. The method of claim 2, The polyethylene glycol is contained in an amount of 0.5 to 5 parts by weight, The titanium compound is a composition for forming a lubricating film is contained in an amount of 1 to 6 parts by weight. 3. The method of claim 2, The composition for forming a lubricant film further comprises at least one selected from the group consisting of vanadium compounds, molybdenum compounds, nickel compounds zinc compounds and manganese compounds. The method according to any one of claims 1 to 5, The composition for forming a lubricating film is a composition for forming a lubricating film having a pH of 1.5 to 6.5. The method of claim 1, The silicone compound is at least one selected from the group consisting of colloidal silica, silane compound and silicon lubricating film forming composition. The method of claim 1, The sulfur compound is a sulfonate compound composition for lubricating film. The method of claim 8, The sulfonate compound is aryl sulfonic acid lubricating film forming composition. The method of claim 9, The aryl sulfonic acid is phenol sulfonic acid composition for forming a lubricant film. The method of claim 1, The phosphorus compound is at least one selected from the group consisting of phosphonates, phosphate compounds and combinations thereof. The method of claim 11, The phosphorus compound is at least one composition selected from the group consisting of hydroxyethylenediphosphonic acid, aminotrimethylenephosphonic acid, methylenephosphonic acid, orthophosphate and pyrophosphate. 3. The method of claim 2, The titanium compound is a composition for forming a lubricating film is at least one selected from the group consisting of a titanium coupling agent, titanium chloride and titanium dioxide. A zinc or zinc-based alloy plated steel sheet containing a lubricating film having silicon film, phosphorus and sulfur on the surface of the steel sheet and having a film removal property by an alkali degreasing solution. 15. The method of claim 14, The lubricating film is zinc or zinc-based alloy plated steel sheet further comprising titanium. 15. The method of claim 14, The lubricating film is zinc or zinc-based alloy plated steel sheet further comprising a compound containing at least one element selected from the group consisting of vanadium, molybdenum, nickel, zinc and manganese. delete Silica compounds; Sulfur compounds; And a lubricating film formed by contacting the surface of the steel sheet with a lubricating film-forming composition containing a phosphorus compound, and having a film removal property by an alkali degreasing solution. The method of claim 18, The lubricating film-forming composition is zinc or zinc-based alloy plated steel sheet further comprising at least one selected from the group consisting of polyethylene glycol and titanium compounds.