KR20000041674A - Method for producing lubricating resin solution of excellent shim processing property and method for processing surface of steel plate using same - Google Patents

Abstract

PURPOSE: A method is provided to prepare a lubricating resin solution having excellent seam processing performance and chemical resistance, to reduce defect in processing and to improve blackening of a processed part. CONSTITUTION: An aqueous polyurethane resin solution is prepared by the following steps. Fluoric resin denatured poly olefin wax of 0.98-1.02 of gravity and of 0.05-0.5 micrometer of particle diameter as a lubricant and polyethylene wax of 1500-3000 of molecular weight and 0.05-1.0 micrometer of particle diameter are mixed in the ratio of 1:0.3-1:0.7. The mixture is added 5-30wt% of resin solid powder. An aziridine or block isocyanate material is added 3-15wt% of the resin solid powder based on the weight of the resin solid powder as a hardening agent. 10-30wt% of colloidal silica is added to the lubricant resin solution. 0.1-0.5WT% of coupling agent selected from a silane coupling agent containing epoxy, amine and acryl and a titanium coupling agent containing phosphor and amine is added to the resin solution. By using pure water, the resin solution is diluted with 10-40wt% of resin solid powder. The aqueous lubricant resin solution is coated on an electrically zinc-plated steel sheet processed with 4-200mg/m¬2 of chrome to make the dried film thickness 0.5-5.0 micrometers. After calcining at 110-200°C, cooling is performed by cooled water.

Description

Lubricating resin solution manufacturing method with excellent deep workability and chemical resistance and steel plate surface treatment method

The present invention relates to a method for producing a lubricating resin solution excellent in deep workability and chemical resistance, and to a steel sheet surface treatment method. More specifically, the present invention relates to a method for preparing a lubricating resin solution having characteristics such as oil-free deep workability, reduced processing defects, improved blackening of the processed portion, and chemical resistance, and a method for treating the surface of the chromate-treated electroplated steel sheet using the same.

Surface treatment techniques for applying a variety of resin solutions to a chromate-treated electroplated steel sheet as thin films to give the steel sheet a possibility are widely known. Among these, Japanese Patent Laid-Open No. Hei 5-138120, Hei 4-44840, Hei 3-71836. The lubricating solution for giving lubricity to a steel plate is disclosed by Pyeong 3-39485, Pyeong 3-16726, Pyeong 3-270932, etc.

However, the above methods do not specifically mention the blackening phenomenon of the processed part after deep processing, or detailed description of the resin which is the main component of the resin solution.

As a lubricant added to impart lubricity to the solution, olefin waxes and some fluorine waxes such as polyethylene, polypropylene, and paraffin are proposed. Among them, polyethylene wax is known to be mainly used. In addition, some of the known techniques using fluorine wax have been introduced, but this fluorine wax has been reported to be less lubricious than polyethylene wax [surface technology, vol 47, No. 8 (1996), lubricated antirust steel sheet]. However, it is known that the fluorine-based resin has a higher wear resistance associated with deep workability than any other polymer material.

Korean patent applications 96-39091 and 97-733554 also mention black stools after processing using polyethylene wax modified with fluorine resin alone. However, the anti-fingerprint steel sheet produced using the coating solution for the anti-fingerprint steel sheet used in the above method has a low applicability during deep processing because it is a case of low difficulty processing mainly for bending and hole processing.

On the other hand, the lubricant coated steel sheet is preferably processed by non-oil, but in some cases, it is often necessary to remove the contamination from the outside during or after the machining process, and in order to prevent damage to the resin film, alkali and solvent resistance are required. There is a need for a lubricating resin solution having excellent chemical resistance such as the like.

As such blackening resistance and chemical resistance are recently applied to computer parts or various home appliance parts that are easily seen inside due to the development of the computer-related industry, the beautiful characteristics of the permanent surface are important even after processing.

Accordingly, an object of the present invention is to provide a method for preparing a lubricating resin solution having characteristics such as oil-free deep processing, reducing processing defects, improving blackening of processed parts, and chemical resistance.

Another object of the present invention is to provide a surface treatment method of a chromate-treated electroplated steel sheet using the lubricant resin solution.

1 is a cross-sectional view of a steel sheet coated with a lubricant resin solution according to the present invention.

According to the first aspect of the present invention,

(a) (iv) 100-130 parts of polyol, 30-50 parts of diisocyanate ester, 55-15 parts of dimethylpropionic acid or dimethylbutyric acid and 5-15 parts of amine as hydrophilic part for water dispersion at 55-85 ° C. Reacting for 6 hours to form a prepolymer such that the proportion of NCO groups is 2-8%;

(Ii) water dispersing the prepolymer by adding 10% by weight of acetone or n-pyrrolidone (NMP) solvent based on the weight of the reactants to the prepolymer at a temperature of 30-40 ° C .;

(Iii) A chain extender selected from the group consisting of glycols, triols and diamines is added to the water-disperse prepolymers at a temperature of 25-30 [deg.] C. with residual NCO% so that the molecular weight of the final product is only 3-10. Introducing while controlling the reaction molar ratio;

Step of preparing an aqueous polyurethane resin solution;

(b) a fluorinated resin-modified polyolipine wax having a specific gravity of 0.98 to 1.02 and a particle diameter of 0.05 to 0.5 μm as a lubricant in the resin solution, and a polyethylene wax having a molecular weight of 1500 to 3000 and a particle diameter of 0.05 to 1.0 μm of 1: 0.3. Adding 5-30 wt% of the mixed mixture at a ratio of ˜1: 0.7, based on the weight of the resin solids;

(c) adding 3 to 15% by weight of an aziridine-based or block-isocyanate-based material as a curing agent to the lubricating resin solution based on the weight of the resin solids;

(d) adding 10 to 30% by weight of colloidal silica to the lubricant resin solution based on the weight of the solid content;

(e) a coupling agent selected from a silane coupling agent containing an epoxy group, an amine group, an acryl group, and the like in the resin solution of step (d) and a titanium coupling agent containing a phosphorus and an amine group, based on the total weight of the resin solids; Adding 0.5% by weight;

(f) diluting the final resin solid content to 10-40% using pure water;

An aqueous lubricating resin solution production method is provided.

According to the second aspect of the present invention,

After applying the aqueous lubricating resin solution prepared above to the electrolytic galvanized steel sheet chromate treated with a chromium deposition amount of 4 ~ 200mg / m ² so that the dry film thickness is 0.5 ~ 5.0μm,

Provided is a method for surface treatment of a chromate-treated electroplated steel sheet characterized by calcining at a steel plate temperature of 110 to 200 ° C. followed by water cooling.

Hereinafter, the present invention will be described in detail.

As described above, according to the method of the present invention, an aqueous lubricating resin solution for steel sheets having characteristics such as non-oil deep workability, processing defect reduction, blackening phenomenon improvement, chemical resistance, etc. is prepared, and an electrogalvanized steel sheet subjected to chromate treatment using the same Surface treatment.

In preparing the aqueous lubricant resin solution of the present invention, an aqueous polyurethane resin having a molecular weight of 3 to 100,000 as a main component is first prepared, and a prepolymer for synthesizing a polyurethane resin is prepared before preparing the polyurethane resin.

In the preparation of the prepolymers, dimethylpropionic acid or dimethylbutyric acid and diisocyanate esters as hydrophilic parts for the polyol and water dispersion are used as reactants. Although the kind of said polyol is not specifically limited, The polybutylene adipate-type polyester whose molecular weight is about 500-2500 is mainly used. In addition, as the diisocyanate ester having a urethane reaction with the polyol, pure diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), tolylene diisocyanate (TDI), or the like may be used alone. Two or more kinds can be mixed and used. On the other hand, dimethylpropionic acid or dimethylbutyric acid is used as the hydrophilic part for water dispersion, because these compounds contain a carboxyl group to perform water dispersion.

The polyol and diisocyanate ester react at a temperature of 55-85 ° C. to produce a prepolymer, wherein the temperature range is a temperature commonly used in polymerization.

On the other hand, an amine is used as a neutralizing agent for solubilizing the prepolymer, which acts not only as a neutralizing agent but also as a catalyst in the urethane reaction of the polyol and the diisocyanate ester. As the amine used in the method of the present invention, triethylamine is preferable. In particular, triethylamine has good water solubility, and since the boiling point is about 80 ° C., it does not remain on the steel sheet when the resin solution is applied thereafter. Because this is good.

The ratio of NCO groups of the prepolymer prepared by the above method should be maintained in the range of about 2 to 8%. This is for the chain growth to occur from the prepolymer to a polyurethane resin having a constant molecular weight.

At the end of the polymerization reaction of the prepolymer, the prepolymer is dispersed, with acetone or n-methyl pyrrolidone (NMP) solvent added to facilitate the dispersion. When the acetone or n-methyl pyrrolidone solvent is used to disperse the prepolymer, the viscosity of the resin solution is lowered to improve the physical properties of the solution.

A chain extender is introduced into the water-dispersible prepolymer thus prepared to synthesize an aqueous polyurethane resin.

Chain extenders which can be used in the method of the present invention include, but are not limited to, glycols such as ethylene glycol, 1,4-butylene glycol and 1,6-hexanediol, and diamines such as ethylenediamine and isophoronediamine. And triols such as trimethylolpropane.

When diols or triols are used as chain extenders, the reactivity with the -NCO groups is small, requiring about 24 hours of reaction time.However, when diamines are used as chain extenders, the rate at which they react with -NCO groups of the prepolymer is increased. It is fast because it takes about 1 hour of reaction time, but it can be selected according to the desired physical properties in the final application.

The chain extender is introduced into the dispersed prepolymer while controlling the residual NCO% and the reaction molar ratio of the prepolymer to prepare an aqueous polyurethane resin having a molecular weight of 3 to 100,000. At this time, when the molecular weight of the water-based polyurethane resin is less than 30,000, the chemical resistance is lowered. If the molecular weight is 100,000 or more, the viscosity of the resin rises and coating workability is not good.

On the other hand, the polymerization reaction is carried out at 25 ~ 30 ℃. Lower temperatures are advantageous for preventing the -NCO groups of the prepolymer from reacting with water during polymerization, but if the temperatures are too low, no reaction occurs.

In the same manner as described above, after preparing and dispersing the prepolymer, a chain extender is introduced into the water-dispersible prepolymer, thereby providing excellent chemical resistance and film forming properties, and an aqueous solution having a molecular weight of 30,000 to 100,000 with improved processability by the resin itself. Polyurethane resin solution is prepared.

A mixture of a fluororesin-modified polyolefin wax and polyethylene wax is added as a lubricant to the resin solution prepared as described above.

When using a mixture of fluororesin-modified polyolefin wax and polyethylene wax, the physical properties of the resin solution can be significantly improved than when used alone. That is, by using a polyethylene wax mixed with a fluororesin-modified polyolefin wax, there is a slight effect in improving deep workability and improving alkali resistance and solution stability.

The fluorine resin modified polyolefin wax used in the present invention is different from the conventional fluorine resin (PTFE) wax and a simple mixture of polyolefin wax, fine fluorine resin wax particles in order to maximize the lubricity and improve the solution properties Alternatively, the polyolefin wax, such as polypropylene, is modified to be enclosed in a form of encapsulation with a significant bonding force, and is dispersed in water, and the specific gravity of the wax can be kept as low as 0.98 to 1.02, thereby exhibiting sufficient lubricity. That is, since the fluorine resin wax having a particle diameter of 0.05 to 0.5 μm is bound around the spherical olefin wax with a small specific gravity, the specific gravity of the wax is reduced, so that sufficient floating force can be obtained on the wet film when coated on the steel sheet, and the ball bearing effect By this, the characteristics of the fluorine resin system can be sufficiently exhibited. Therefore, the appearance after deep processing which receives a large processing load is particularly excellent.

In the method of the present invention, a polyethylene wax having a molecular weight of 1500 to 3000 and a particle size of 0.05 to 1.0 µ is used in order to improve compatibility with an aqueous solution. Polyethylene wax mixed with the fluororesin-modified polyolefin wax. Because of excellent compatibility with the binder resin of the lubricating resin solution, unlike the fluorine resin-modified polyolefin wax which is widely distributed in the coating layer, it is uniformly distributed in the resin coating and provides a synergistic effect on the deep workability.

On the other hand, the fluororesin modified polyolefin wax and polyethylene wax is mixed in a weight ratio of 1: 0.3 ~ 1: 0.7. At this time, when the mixing ratio of the polyethylene wax based on the fluorine resin modified polyolefin wax is 0.3 or less, the effect of the polyolefin wax is not sufficiently exhibited. Is lowered.

The wax mixture is added in an amount of 5 to 30% by weight based on the resin solid content. When the amount is 5% by weight or less, the surface friction characteristics are somewhat improved, but the deep workability is significantly reduced. Rather, it does not improve, but rather an additional property degradation.

Next, an aziridine-based or block isocyanate-based curing agent is added to the lubricant resin solution.

Although the polyurethane resin produced by the method of the present invention exhibits excellent chemical resistance only, traces of fine resin dissolution are observed under strong alkali conditions, and thus the curing agent is used to improve chemical resistance and surface properties.

The aziridine-based or block isocyanate-based curing agent is added to 3 to 15% by weight based on the weight of the resin solids. At this time, when the curing agent is added at 3% by weight, the alkali resistance effect does not appear significantly, and when added at 15% by weight or more, solution stability and processability are deteriorated.

Subsequently, in order to improve corrosion resistance, colloidal silica is added to the lubricant resin solution in an amount of 10 to 30% by weight based on the resin solid content, but when it is added in an amount of 10% by weight or less, the corrosion resistance effect is not sufficient, and it is added at 35% by weight or more. Under the influence of silica having a high hardness, deep workability is degraded, and scratching blackening of the processed part occurs.

Next, the silane coupling agent containing an epoxy group, an amine group, and an acryl group, or the titanium coupling agent containing phosphorus and an amine is added to the said lubrication resin solution. When these coupling agents are added, the film strength is increased to improve gloss and workability, and the silica is uniformly dispersed in the film to obtain a synergistic effect of improving corrosion resistance. The addition amount of the said coupling agent is 0.1-0.5 weight% as a normal usage-amount based on resin solid content.

Finally, to adjust the solid content of the final solution to 10 to 40% by weight using pure water to facilitate the thin film coating of the lubrication resin solution prepared as described above, in this case 10% by weight or less, or 40% by weight or more This is because it is difficult to easily induce a thin film coating when applied to a steel sheet.

In the same manner as described above, after the aqueous polyurethane resin solution is prepared, an aqueous lubricant resin solution is prepared by adding and diluting a lubricant, a curing agent, an additive, a coupling agent and the like to the resin solution.

In addition, according to the present invention there is provided a method for applying the lubricating resin solution of the present invention to the chromate-treated electroplating steel sheet having characteristics such as non-oil deep processing, reduced processing defects, blackening phenomenon and chemical resistance prepared as described above do.

As a steel plate to which the resin lubricating solution of the present invention is applied, an electroplated steel sheet having a chromium adhesion amount of 4 to 200 mg / m ² is used, and when the chromium adhesion amount is 4 mg / m ² or less, it is difficult to show corrosion resistance, and 200 mg / When applied in more than m ² corrosion resistance is excellent while coating film adhesion is lowered.

As a method of applying the lubricating resin solution to the electroplated steel sheet, it may be applied by a conventional method such as a roll coating method or a spray method, and the thickness of the dry resin film is 0.5 to 5 μm. At this time, if the thickness of the dry film is 0.5μm or less, it does not show the lubricity and processability of the film, and if it is 5μm or more, the film properties are excellent, but the amount of resin that is squeezed into the mold during deep processing increases greatly, resulting in workability during subsequent processing. Is generated.

In addition, the lubricating resin of the present invention is cured by the heat supplied during the baking process, the preferred baking temperature associated with resin hardening is 110 ~ 200 ℃ based on the steel sheet temperature, the resin is not fully cured at the steel sheet temperature of 110 ℃ or less chemical resistance Not only is this reduced, but also an undried condition occurs, and it is not preferable to cause a change in the steel sheet material due to heat above 200 ℃.

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

Example 1

The lubricated resin solution prepared under the conditions shown in Table 1 was dispersed in 20% by weight of the solids in the final resin solution, and the chromate-treated electric material having a zinc adhesion amount of 20 g / m ² , a steel plate thickness of 0.8 mm and a chromate adhesion amount of 50 mg / m ² . The coating film is coated on the zinc sheet to have a thickness of 1.5μm and then baked at a temperature of 160 ° C in a self-draining oven, followed by water cooling to provide chemical resistance, coefficient of friction, processability, deep workability and appearance after processing. The physical properties as described above are evaluated and the results are shown in Table 1.

The corrosion resistance was evaluated by initial white rust generation time in a salt spray tester according to JIS Z 2731.

Corrosion resistance evaluation (time) ◎ (very good): 350 or more, ○ (excellent): 300 to 350

△ (lack): 250 ~ 300 × (bad): less than 250

The chemical resistance evaluation was exemplified by evaluating solvent resistance and alkali resistance.

Solvent resistance evaluation was evaluated by immersing a methyl ethyl ketone (MEK) solvent in a gauze and rubbing the resin coated surface 20 round trips and observing the degree of dissolution of the coating.

Alkali resistance evaluation was performed by degreasing spraying and dipping degreasing by alkaline degreasing solution for 150 seconds at 60 ° C under degreasing solution and degreasing conditions, which are mainly used in home appliance makers for forming steel sheets, and then rinsing with air for two times. The color difference value (ΔE) before and after degreasing was measured as a color difference meter for the dried specimens and evaluated as follows.

Chemical resistance evaluation (ΔE) ◎ (very good): 0.5 or less, ○ (excellent): 0.6 to 0.8

△ (lack): 0.9 ~ 1.5 × (bad): 1.5 or more

The coefficient of friction was evaluated using a one-sided friction tester with a value of 0.27kg / cm ² applied pressure and a drawing speed of 1m / min under oil-free conditions.

Evaluation of friction coefficient (μ) ◎ (very good): 0.075 or less, ○ (excellent): 0.075 ~ 0.085

△ (lack): 0.085 ~ 0.095 × (defect): 0.095 or more

Deep workability evaluation was performed after the plane strain stretch test (PSST) under the condition of 30 tons blank holdung force and punch speed 230mm / min in sheet metal forming tester without oiling. LDH) was evaluated as follows. At this time, the LDH value of the steel sheet before lubricating resin coating was measured after lubricating low viscosity lubricating oil, which is about 32 to 35 mm.

Deep workability evaluation (mm) ◎ (very good): 45 or less, ○ (excellent): 42 ~ 45 level

△ (lack): 38 ~ 42 level × (bad): 38 or less

The appearance after processing is mainly for evaluating the blackening phenomenon of the processed surface. The color change of the friction surface after the draw bending test was evaluated by the color difference (ΔE) value before and after using the color difference meter as follows.

Appearance evaluation after processing ◎ (very good): 0.5 or less, ○ (excellent): 0.5 ~ 2.0

△ (lack): 2.0 ~ 4.0 × (bad): 4.0 or more

division Composition (% by weight) Quality characteristics Remarks slush Silica Hardener Corrosion resistance Chemical resistance Coefficient of friction Deep processability Processing appearance Inventive Example 1 5 10 10 ○ ○ ○ ○ ○ Inventive Example 2 5 20 5 ◎ ○ ○ ○ ○ Inventive Example 3 10 10 7 ○ ◎ ◎ ○ ◎ Inventive Example 4 10 15 10 ○ ◎ ◎ ◎ ○ Inventive Example 5 15 20 15 ◎ ◎ ◎ ◎ ◎ Inventive Example 6 20 20 3 ◎ ○ ◎ ◎ ◎ Inventive Example 7 20 30 12 ◎ ◎ ◎ ◎ ◎ Inventive Example 8 25 30 7 ◎ ◎ ◎ ◎ ○ Inventive Example 9 30 35 12 ◎ ◎ ◎ ◎ ○ Comparative Example 1 3 15 7 ○ △ × × × Comparative Example 2 32 20 7 △ ○ ◎ ◎ ◎ Comparative Example 3 35 20 10 △ △ ◎ ◎ ◎ Comparative Example 4 20 5 10 △ ◎ ◎ ◎ ◎ Comparative Example 5 20 40 10 ◎ ◎ △ × × Scratch Comparative Example 6 10 30 2 ◎ × ◎ ○ ○ Comparative Example 7 10 30 17 ◎ ◎ ○ × × Solution stability deterioration

Hereinafter, the test results of Table 1 will be described in detail by dividing the invention example and the comparative example.

Inventive Examples 1 to 9

As a result of evaluating the quality characteristics of the lubricant coated steel sheet treated with the lubricant resin solution prepared by the method of the present invention, it shows excellent physical properties as shown in Table 1 above.

Comparative Examples 1 to 3

When the content of the lubricant used in the preparation of the lubricant resin is lower than the range of the present invention overall poor workability, when higher than the range of the present invention was found that the processability is no longer improved, but rather the corrosion resistance is reduced.

Comparative Examples 4 to 5

When the content of silica used in the preparation of the lubricating resin solution was lower than the range of the present invention, the corrosion resistance was poor. When the content of the silica was higher than the range of the present invention, blackening phenomenon and scratches occurred in the processing part due to the influence of silica having a high hardness. And deep processability was greatly reduced.

Comparative Examples 6 to 7

When the content of the curing agent used in the preparation of the lubricating resin solution is lower than the range of the present invention, the chemical resistance is lowered, especially as the alkali resistance tends to decrease. Workability was poor, such as local resin peeling occurred.

Example 2

By changing only the mixing ratio of the wax in the composition of Inventive Example 7 of Example 1, the properties according to the mixing ratio of the fluororesin-modified polyolefin wax and polyethylene wax are investigated and shown in Table 2.

division Polyethylene Wax Mixing Ratio ^* Quality characteristics Remarks Deep processability Processing appearance Comparative Example 1 0 △ ○ Comparative Example 2 0.1 △ ○ Comparative Example 3 0.2 △ ○ Inventive Example 1 0.3 ○ ◎ Inventive Example 2 0.4 ○ ◎ Inventive Example 3 0.5 ◎ ◎ Inventive Example 4 0.6 ◎ ◎ Inventive Example 5 0.7 ○ ○ Comparative Example 4 0.8 △ △ Poor solution stability

*: Mixing ratio when fluororesin-modified polyolefin wax is 1

Hereinafter, the results of Table 2 will be described in detail by dividing the invention examples and comparison.

Inventive Examples 1 to 5

As shown in Table 2, it can be seen that when the fluororesin-modified polyolefin wax and the polyethylene wax are mixed and used in the mixing ratio according to the method of the present invention, the deep workability and the processing appearance are excellent.

Comparative Examples 1 to 4

When preparing a lubricant resin solution, when the polyethylene wax is not mixed or lower than the range of the present invention, there is a limit in the deep processing property of the fluororesin-modified polyolefin wax, and when the mixing ratio of the polyethylene wax is higher than the range of the present invention. Since the physical properties of the polyethylene wax were superior to those of the fluororesin-modified polyolefin wax, no mixing effect was observed.

As described above, the lubricating resin solution prepared by the method of the present invention is coated with a thin film on the steel sheet and exhibits excellent anti-corrosion characteristics such as corrosion resistance, chemical resistance, deep processing property, appearance after processing, surface friction characteristics, and the like. Molding of the product is possible, thus eliminating the degreasing process, thereby reducing environmental pollution.

Claims (5)

(a) (iv) 100-130 parts of polyol, 30-50 parts of diisocyanate ester, 55-15 parts of dimethylpropionic acid or dimethylbutyric acid and 5-15 parts of amine as hydrophilic part for water dispersion at 55-85 ° C. Reacting for 6 hours to form a prepolymer such that the proportion of NCO groups is 2-8%; (Ii) water dispersing the prepolymer by adding 10% by weight of acetone or n-pyrrolidone (NMP) solvent based on the weight of the reactants to the prepolymer at a temperature of 30-40 ° C .; (Iii) A chain extender selected from the group consisting of glycols, triols and diamines is added to the water-disperse prepolymers at a temperature of 25-30 [deg.] C. with residual NCO% so that the molecular weight of the final product is only 3-10. Introducing while controlling the reaction molar ratio; Step of preparing an aqueous polyurethane resin solution; (b) a fluorinated resin-modified polyolipine wax having a specific gravity of 0.98 to 1.02 and a particle diameter of 0.05 to 0.5 μm as a lubricant in the resin solution, and a polyethylene wax having a molecular weight of 1500 to 3000 and a particle diameter of 0.05 to 1.0 μm of 1: 0.3. Adding 5-30 wt% of the mixed mixture at a ratio of ˜1: 0.7, based on the weight of the resin solids; (c) adding 3 to 15% by weight of an aziridine-based or block-isocyanate-based material as a curing agent to the lubricating resin solution based on the weight of the resin solids; (d) adding 10 to 30% by weight of colloidal silica to the lubricant resin solution based on the weight of the solid content; (e) a coupling agent selected from a silane coupling agent containing an epoxy group, an amine group, an acryl group, and the like in the resin solution of step (d) and a titanium coupling agent containing a phosphorus and an amine group, based on the total weight of the resin solids; Adding 0.5% by weight; (f) diluting the final resin solid content to 10-40% using pure water; Aqueous lubricating resin solution manufacturing method consisting of. The method of claim 1, wherein the polyol is a polybutylene adipate-based polyester polyol having a molecular weight of about 500 to 2500. The method of claim 1 wherein the diisocyanate ester is selected from the group consisting of diphenylmethane diisocyanate, isophorone diisocyanate and tolylene diisocyanate. The method of claim 1 wherein the amine is triethylamine. On electrogalvanized steel plates chromated with a chromium deposit of 4 to 200 mg / m ² After applying the aqueous lubricant solution prepared in claim 1 so that the dry film thickness is 0.5 ~ 5.0μm, A surface treatment method of a chromate-treated electroplated steel sheet characterized by calcining at a steel plate temperature 110 ~ 200 ℃ and then water cooled.