JPH09267071A - Lubrication treated steel sheet having high working characteristic and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication treated steel sheet which prevents the direct contact with metal molds by increasing the thickness of surface lubricant coating layers, consists of films having the structure to be replenished with the lubricant from the inside of the films at all times and to maintain good lubricative workability in spite of the drastic deformation of the films in deep drawing and ironing, etc., by a combination of the lubricant articles of different diameters as the particles to be dispersed into the films and a change in their concn. and has a high working characteristic and a process for producing the same. SOLUTION: The films of an ether ester type urethane resin and epoxy resin contg. 10 to 40% silica and 10 to 40% polyolefin wax are formed at 1.0 to 5μm film thickness on the surfaces 1, 2 of the plated steel sheet subjected to a chemical conversion treatment. The particles sized <=1μm of the lubricant 5 are incorporated at 20 to 60% and the particles sized >=2μm at 8.0 to 40% into the lubricating layers 4. In addition, the particles are dispersed therein at a concn. of 10 to 40%. The surface of the lubricant layers are provided with the surface lubricant coating layers 6 at 0.4 to 1.5μm thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricated steel sheet used for parts such as home electric appliances, building materials and automobiles having excellent high working characteristics and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a lubricating resin-treated steel sheet having excellent workability has been given a work lubrication characteristic by dispersing a lubricant in a coating film. Is generally known to deteriorate. It is said that this is because the softening of the base resin makes the base resin sticky and impairs the lubricity with the mold. As a solution to these problems, a resin having a hydroxyl group and / or a carboxyl group on one surface of a plated steel sheet, silica, and a solid lubricant are used, as in JP-A-1-301333 using a resin containing a high glass transition temperature. The resin mixture or composite containing the resin coating has a glass transition temperature of 70 ° C. or higher, and the other surface has a resin coating containing a resin having a hydroxyl group and / or a carboxyl group and silica. Excellent lubricating resin treated steel plate,
A method using a lubricant having a particle diameter larger than the film thickness, a high melting point lubricant, or the like has been attempted. But,
Regarding these techniques, it is said that sufficient workability is not obtained during strong ironing under strong surface, the types of resins that can be selected are limited, the elongation characteristics are not sufficient, and the paint easily separates. There is a problem in workability, and there is a problem that the optimum lubricating diameter changes depending on the film thickness.

Therefore, the applicants of the present invention, Japanese Patent Laid-Open No. 6-1551,
As described in Japanese Patent Publication No. 84-84,
As a layer, a chemical conversion film of a chromate film having a Cr adhesion amount of 5 to 100 mg / m ² or a phosphate film having an adhesion amount of 0.2 to 2.0 g / m ^2, a bisphenol type skeleton as a second layer,
Ether with ester skeleton and carboxyl group
The total amount (a + b) of the ester type urethane resin (a) and the epoxy resin (b) is 50 to 85% by weight based on the total solid content,
A film thickness of 0.2 obtained by applying and baking an aqueous lubricant coating containing 3 to 30% by weight of polyolefin wax (c) and 10 to 40% by weight of silica (d) having a particle size of 3 to 30 nm.
We have already proposed a non-film-removal type lubrication plated steel sheet with a coating film of up to 5 μm that can omit pressing oil.

[0004]

However, in the above-mentioned Japanese Patent Laid-Open No. 6-155184, as shown in FIG. 9, a plating film 2, a chromate or phosphate conversion film 3, on a thin steel plate 1, In the coating structure composed of the lubricating coating 4, the lubricant 5 is dispersed in the lubricating coating 4 to provide the working lubrication property, but the workability during the strong ironing under a strong surface is deteriorated and the workability is sufficiently deteriorated. There is a problem that lubricity cannot be obtained. Therefore, in order to solve these problems, as a result of intensive development by the inventors, as a result of increasing the thickness of the surface lubricant coating layer, direct contact of the mold is prevented,
Also, by combining different diameter lubricant particles in the coating and changing the concentration, even if the coating is severely deformed during deep drawing and ironing, lubrication is constantly replenished from inside the coating, and good lubrication workability is maintained. The present invention provides a lubricated steel sheet having excellent workability and a method for producing the same, which is made of a coating having the structure described above.

[0005]

The present invention advantageously solves the problems of the prior art as described above, and the gist of the invention is as follows. The amount of Cr deposited as a layer is 5
100 mg / m ² chromate coating or coating weight
2~2.0g / m ² of phosphate salt coating of the chemical conversion coating, the sum of bisphenol skeleton as the second layer, ester skeleton and ether ester type urethane resin having a carboxyl group (a) and epoxy resin (b) ( a + b) 50 to 85% by weight based on the total solid content, 10 to 40% by weight of polyolefin wax (c), and 10 to 40% by weight of silica (d) having a particle size of 3 to 30 nm are applied. The lubricating layer thickness obtained by baking is 1.0 to 5 μm, and lubricant particles in the lubricating layer are 1 μm or less 20 to 60% and 2 μm.
80 to 40% of m or more, and a particle concentration of 10 to 4
A lubricated steel sheet excellent in high working characteristics, which is obtained by dispersing 0% and providing a surface lubricant coating layer thickness of 0.4 to 1.5 μm as a third layer on the lubricating layer.

(2) C as the first layer on the surface of the plated steel sheet
r A chemical conversion coating of a chromate film having an attached amount of 5 to 100 mg / m ² or a phosphate film having an attached amount of 0.2 to 2.0 g / m ² , and an ether having a bisphenol type skeleton, an ester skeleton and a carboxyl group as the second layer * Sum of ester type urethane resin (a) and epoxy resin (b) (a +
b) is 50 to 85% by weight based on the total solid content, 10 to 40% by weight of the polyolefin wax (c), and a particle size of 3 to 30.
After applying a water-based lubricating paint containing 10 to 40% by weight of silica (d) of 10 nm, baking plate temperature is 120 ° C. or more, baking time is 10 seconds or more, and lubricant particles are 1 μm or less 20 to 60% in the lubricating layer. 2 μm or more of 80 to 40% and having a particle concentration of 10 to 40% dispersed, and baked on the lubricating layer so that the surface lubricant coating layer has a thickness of 0.4 to 1.5 μm. And a method of manufacturing a lubricated steel sheet having excellent high working characteristics.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a coating film structure of a lubricated steel sheet having excellent high workability according to the present invention. That is, it has a coating structure consisting of a plating coating 2, a chromate or phosphate coating 3, a lubricating coating 4 and a surface lubricating coating layer 6 on a thin steel sheet 1, and a lubricant 5 is dispersed in the lubricating coating 4. Exists in a state. Each of these coatings can have different thicknesses on both sides, one side or both sides, and coating compositions, depending on the application. Further, for example, the lubricating coating is resin + silica + polyolefin wax 1.
0 to 5.0 μm, conversion coating is Cr 5 to 100 mg / m ²
Or phosphate 0.2-2.0 g / m ² , plating is Z
n, Zn alloy, Al, Al alloy plating, plating amount 5 to
It consists of 200 g / m ² . The present invention is basically applicable to all thin steel sheets, ie, aluminum-killed steel sheets, ultra-low carbon steel sheets, and high-strength steel sheets.

The plating is electroplating, hot dipping, zinc obtained by vapor plating, zinc alloy plating, and multi-layered steel sheet, aluminum, aluminum alloy plating and multi-layered steel sheet. As the chemical conversion coating, a chromate coating or a phosphate coating is used. The chemical conversion coating is located between the plating surface and the lubricating coating and provides adhesion during processing, corrosion resistance, and the like. The chromate is a post-wash type electrolytic reduction chromate containing trivalent chromium hydrated oxide as a main component, and a post-wash type etch chromate liquid containing trivalent chromium and hexavalent chromium hydrated oxide as a main component is applied and dried. An anhydrous washing type chromate coating can be used. Adhesion amount is 5 to 100 mg in terms of Cr
/ M ² . If it is less than 5 mg / m ² , corrosion resistance cannot be obtained, which is not preferable. If it exceeds 100 mg / m ² , the cohesive failure of the chromate itself is likely to occur, and the adhesion cannot be obtained. It is desirable that the chromate film is difficult to dissolve in a water-based lubricating paint having a high trivalent chromium / hexavalent chromium ratio.

The phosphate coating is composed of phosphates such as zinc, iron, nickel, manganese and calcium. The amount of adhesion is preferably in the range of 0.3 to 2.0 g / m ² for reasons of corrosion resistance and adhesion. If it is less than 0.3 g / m ² , corrosion resistance cannot be obtained. If it exceeds 2.0 g / m ² , adhesion cannot be obtained by severe processing due to cohesive failure of the phosphate film.

The lubricating coating of the present invention will be described below.
A first feature of the present invention resides in that a resin of an appropriate type is blended at a constant weight ratio as a base resin. It is necessary that the resin has a well-balanced component of adhesion, elongation, shear strength, corrosion resistance, abrasion resistance, and chemical resistance. In order to satisfy these performances, it is preferable to use a combination of the resins of the present invention. The present inventors have already obtained a strong workability and corrosion resistance by blending a urethane resin and an epoxy resin and blending a specific polyolefin wax, but as a result of further intensive research, the urethane resin By specifying the structure, it was found that particularly excellent performance was exhibited.

In order to achieve high workability and high corrosion resistance,
It is premised that the coating film is uniform and has excellent adhesion, and it is important that the strength and the elongation are balanced. By using a urethane resin with a large molecular weight and an epoxy resin together, it is easier to control the basic physical properties than a film made by cross-linking resins of low molecular weight, and even a thin film with a coating amount of 1.0 to 5 μm It was found that uniform physical properties were easily obtained. The low-molecular-weight urethane resin is of a type containing various isocyanate-based crosslinking agents. As a resin, a combination of a urethane resin with a molecular weight of 3,000 or more and excellent abrasion resistance and an epoxy resin with excellent adhesion or film strength improvement exhibits particularly various properties such as high workability and corrosion resistance. Base resin suitable for

The urethane resin of the present invention has a molecular weight of 300.
A water-dispersible ether / ester type urethane resin (a) having a bisphenol type skeleton and an ester skeleton and having a carboxyl group of 0 or more, and the epoxy resin (b) having a glycol skeleton or a bisphenol skeleton; , (A) in a ratio that causes 20 to 100% of the carboxyl groups to react. By using the polymer urethane resin of the present invention, uniform film formability in a thin film can be obtained and the object of the present invention can be achieved, but more preferably, the elongation of the coating film is 100% or more and the tensile strength is 100 kg /
The highest workability can be obtained by applying a resin having a size of ² cm ² or more.

Examples of the polyether polyol having a urethane resin skeleton used in the present invention include polyols obtained by adding ethylene oxide and propylene oxide to low molecular weight glycols such as ethylene glycol, propylene glycol and bisphenol A, and polyoxytetramethylene glycol. Among them, a polyether polyol having a bisphenol A skeleton is particularly preferable.
Examples of the polyester polyol include a polyester obtained by a dehydration condensation reaction of a low molecular glycol and a dibasic acid, and a lactam polyol obtained by ring-opening polymerization of a lactam such as ε-caprolactam in the presence of a low molecular glycol.

As the isocyanate group for connecting the ester skeleton and the ether skeleton of the urethane resin, monomers, dimers, trimers of aromatic diisocyanates such as trireisocyanate, diphenylmetadiisocyanate and xylylenediisocyanate, and those Of a polyol with a polyether polyol or polyester polyol, and their hydrogenated derivatives, alicyclic isocyanates such as alicyclic isocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, and monomers and dimers of aliphatic isocyanate A reaction product of a trimer with a polyether polyol or a polyester polyol, or a mixture thereof can also be used. The blending amount depends on the molecular weights and ratios of the polyester polyol, polyether polyol and the carboxyl group-introducing component to be used, but 5 to 20% by weight of the urethane resin in terms of NCO can obtain optimum processing characteristics as resin properties.

The carboxyl group is a functional group for self-emulsification, and contributes greatly to the adhesion to the metal surface. The carboxyl group-introducing component is a compound containing two or more hydroxyl groups or an amino group and one or more carboxyl groups, 2,2-dimethylolpropionacetic acid, 2,2-dimethylolpropionic acid,
Examples thereof include dihydroxycarboxylic acids such as 2,2-dimethylolbutyric acid and 2,2-dimethylolpentanoic acid, and diaminocarboxylic acids such as lysine and arginine. A carboxyl group compound selected from these is polymerized with an isocyanate compound in combination with the polyester polyol and polyether polyol. According to this method, an ether / ester type urethane resin having a carboxyl group having a molecular weight of 3000 or more used in the present invention can be obtained.

Examples of the method of dispersing the urethane resin in water include a method of neutralizing a carboxyl group with an alkali such as ammonia or trimethylamine to self-emulsify, or a method of emulsifying and dispersing using an emulsifier.
As a work environment countermeasure, it is most preferable to recover the solvent contained in the urethane production step before the aqueous system is used and finally obtain a solvent-free type aqueous dispersion. The amount of the carboxyl group is suitably from 10 to 50 in terms of acid value per urethane solid content. If it is less than 10, the adhesion is insufficient and the workability and the corrosion resistance are poor. If it exceeds 50, the water resistance and alkali resistance are poor, and the corrosion resistance is lowered.

The amount of the epoxy resin having a reactive functional group (hydroxyl group, epoxy group, etc.) is preferably such that 20 to 100% of the carboxyl groups of the urethane resin react. If the amount is less than 20%, the compounding effect is poor. If the amount exceeds 100%, the epoxy resin plays a role of a plasticizer, so that a high degree of processability is reduced.
In addition, the epoxy resin has a large effect of improving chemical resistance and corrosion resistance. When a structure having a bisphenol A-type skeleton is used for the epoxy resin, the effect of improving adhesion and corrosion resistance is particularly large. When a solvent-free type or an emulsifier-free type is required as an environmental measure to prevent a decrease in coating film performance, a water-soluble epoxy resin can be obtained by imparting hydrophilicity with a glycol skeleton.

It is necessary to determine the compounding amount of the epoxy resin according to the acid value of the urethane resin, and the calculation method is as follows. Assuming that the carboxyl group of the urethane resin and the epoxy group of the epoxy resin react in an equivalent amount, the following formula is used to determine the required amount of the epoxy resin for 100% reaction with the urethane resin having a predetermined acid value (AV). There is. Epoxy solid content weight (g) = AV value of urethane resin x
(1/56) / 1000 x epoxy equivalent x urethane resin compounding weight (g)

Since the epoxy group compounded in the present invention cross-links with the carboxyl group, the carboxyl group which contributes to the adhesiveness does not correspond to the reaction, but when the epoxy group is opened, O
Since H groups are generated, adhesion is secured. In addition, the corrosion resistance is greatly improved by blending the epoxy resin. A combination of a urethane resin having a molecular weight of less than 3000 and the above-described epoxy resin does not stably achieve high workability. In addition, high film formability and high corrosion resistance cannot be obtained by film formation using only a urethane resin having a molecular weight of 3000 or more. The total weight of the urethane resin (a) and the epoxy resin (b) of the water-based lubricating coating composition of the present invention is appropriately 50 to 85% in terms of solid content ratio to the total solid content. If it is less than 50% or exceeds 85%, the corrosion resistance and workability are insufficient. However, the desired workability cannot be achieved only with these resin-based coatings, so that it is necessary to use a lubricating additive in combination.

Examples of the lubricating additive include known fluorine-based, hydrocarbon-based, fatty acid amide-based, ester-based, alcohol-based, metal soap-based and inorganic-based lubricants. As a criterion for selecting a lubricating additive for improving processability, it is necessary to select a substance in which the added lubricant is present on the surface of the resin film rather than being dispersed in the formed resin film. It is necessary in order to reduce the friction between the surface of the mold and the mold and maximize the lubrication effect. That is, when the lubricant is dispersed in the formed resin film, the surface friction coefficient is high and the resin film is easily broken, and the powdery substance is separated and deposited, resulting in poor appearance and reduced workability called a powdering phenomenon. . As the substance existing on the surface of the resin film, a substance which is not compatible with the resin and has a small surface energy is selected.

As a result of the study by the present inventors, it was found that the use of the polyolefin wax greatly improved the workability and improved the performance such as the corrosion resistance and the chemical resistance after the processing. Examples of the wax include hydrocarbon waxes such as paraffin, microcrystalline or polyethylene. At the time of processing, the melting point of the wax is 70 to
160 ° C. is appropriate, and if it is lower than 70 ° C., it softens and melts during processing and does not exhibit excellent properties as a solid lubricating additive. On the other hand, if the melting point exceeds 160 ° C., hard particles are present on the surface and the frictional characteristics are reduced, so that high moldability cannot be obtained.

It is preferable to use a polyolefin wax having a saponification value of 30 or less or 0 and having a branched structure. Those having a saponification value of more than 30 have a high polarity and are easily compatible with the resin, so that they are unlikely to be present on the resin surface at the time of film formation. Therefore, they cannot be said to be appropriate when a high processing performance level is required.
Particularly preferred is a wax having a saponification value of 0 and having no ester bond having a lower compatibility with the resin. The particle size of these waxes is preferably 2.0 or more. 2.
If it is less than 0 μm, the ironing workability is insufficient. The amount of the lubricating additive is 10 to 40% in terms of solid content relative to the total solid content of the lubricating coating. If less than 10%,
The effect of improving ironing workability is small, and if it exceeds 40%, the workability and corrosion resistance decrease.

As another additive, 10 to 40% of SiO ₂ is added to the total solid content in order to improve the corrosion resistance. The addition of SiO ₂ has the effect of significantly improving corrosion resistance and processability. If it is less than 10%, the effect of improving the corrosion resistance and workability is small, and if it exceeds 40%, the binder effect of the resin becomes small, the corrosion resistance is reduced, and the elongation and strength of the resin are reduced, so that the workability is reduced. Si
The particle size of O ₂ is preferably 3 to 30 nm. 3
If it exceeds 0 nm or is less than 3 nm, higher workability and corrosion resistance cannot be obtained. Types of silica include liquid-phase colloidal silica and gas-phase silica,
The present invention is not particularly limited. In addition, a conductive material for improving weldability or a coloring pigment for improving design may be added. Further, various additives such as an anti-settling agent, a leveling agent and a thickening agent may be added.

The thickness range of the lubricating coating of the present invention is 1.0 to
It is 5.0 μm. The optimum film thickness depends on the form of processing and is difficult to limit. However, a thick film is not suitable for deep drawing and ironing, and if it is less than 1.0 μm, lubricating performance for high processing cannot be obtained. If the length is 5.0 μm, a large amount of blocking and press debris of the coil is generated, which is not preferable. FIG. 2 is a diagram showing a film forming process of the lubricated steel sheet according to the present invention. First, a convection phenomenon occurs in the coating liquid in the first step of the baking step immediately after coating, and the lubricant particles dispersed in the second step are exposed on the surface accordingly. At this time, the surface of the lubricant particles exposed on the surface is dried by the atmosphere in the furnace in the third step, and the surface activity is reduced. Therefore, the lubricant particles once exposed on the surface are fixed on the surface without sinking into the coating film, and are baked at a temperature higher than the melting point as they are, so that they are melted on the surface of the coating film as in the fourth step and the lubricant layer is formed. To form. This is the surface lubricity coating layer.

The dispersion concentration of the lubricant particles in the resin coating of the present invention, and the optimum values of the lubricating layer thickness and the surface lubricating coating layer thickness will be described below with reference to the drawings. FIG. 3 is a diagram showing the relationship between the thickness of the surface lubrication coating layer and the strong working characteristics. FIG. 3 shows the evaluation of the surface lubricating layer thickness and the strong workability such as ironing when the film thickness of lubrication is 3 μm.
The values satisfying the strong workability score of 4 or more in the case of 4 μm or more are shown. Similarly, FIG. 4 is a diagram showing the relationship between the lubricant particle size and the surface lubricant coating layer thickness. FIG. 4 is a diagram showing the relationship between the lubricant particle size and the surface lubricant coating layer thickness when the lubricant concentration is 10%, 20% and 40%. It shows that 0.4 to 1.5 μm is necessary when the particle diameter is 2 μm or more.

FIG. 5 is a graph showing the relationship between the different particle size lubricant concentration ratio and the strong working characteristics. As shown in FIG. 5, when the lubricant concentration ratio of different particle size (1 μm or less / 2 μm or more) is 1 μm or less, 2
In the case of 0 to 60% and 80 to 40% for 2 μm or more, a good strong workability with a strong workability score of 5 is shown. FIG. 6 is a diagram showing the relationship between the concentration of dispersed particles in the lubricating coating and the workability score. This FIG. 6 shows the workability evaluation at a lubricating layer thickness of 1 μm, 3 μm and 5 μm.
When the concentration of dispersed particles in the lubricating coating in μm is 10% or more, a good workability of 4 or more is shown.

FIG. 7 is a diagram showing the relationship between the baking time at each baking temperature and the surface lubricating coating thickness. According to this figure, in order to obtain a surface lubricating coating thickness of 0.1 μm or more,
It shows that a baking plate temperature of 120 ° C. or more requires a baking time of 10 seconds or more. FIG. 8 is a diagram showing the relationship between the baking time and the strong working characteristics. As shown in this figure, at a baking plate temperature of 120 ° C. or higher, a good strong processing characteristic (processing score ≧ 4) is obtained when the baking time is 10 seconds or more. It is preferable that a baking temperature of 150 ° C. or higher and a baking time of 15 seconds or more provide better processing characteristics.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples applied to hot-dip galvanized steel sheets. Ether ester urethane resins (bisphenol A ether Cr adhesion amount 15 mg / m ² of the coating chromate treatment and molecular weight of 5000 to galvanized steel sheets were: acid number 18, ether /
Ester ratio 30/70, isocyanate content 8) and propylene glycol epoxy resin (epoxy equivalent 22
To 0), a lubricant coating was prepared by mixing 25% of silica sol having an average particle size of 10 nm, 30% of polyethylene wax having a particle size of 1.0 μm or less, 40%, 2 μm or more and 60% (specific gravity 0.93, softening point 120 ° C.). , A plate temperature of 120 ° C., a baking time of 15 seconds, and a plate temperature of 150 ° C. and a baking time of 18 seconds, the lubricant particles in the lubricating layer are 1 μm or less 40%, 2 μ
m and 60%, and the particle concentration is 30% dispersed, and the surface lubricating coating layer thickness is 1.0 μm and 1.2 μm.
m lubricated steel sheet was prepared. The obtained lubricous steel sheets having the surface lubricating coating layer thicknesses of 1.0 μm and 1.2 μm had good friction performances of 0.07 and 0.06, respectively, which are the lubricating characteristics. In addition, the processing evaluation, which is the ironing processing characteristic, was 5 for each, and extremely good high processing performance was obtained.

[0029]

As described above, by increasing the thickness of the lubricating coating layer on the surface according to the present invention, direct contact with the mold is prevented, and the particles dispersed in the coating are combined and concentrated in different diameter lubricating particles. Even if the coating is severely deformed during deep drawing and ironing due to the change of, the lubricant is constantly replenished from the coating, and good lubrication workability can be maintained, and there is little deterioration of the coating due to processing It is possible to provide a lubricated steel sheet having excellent high workability and a method for producing the same.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a coating structure of a lubricated steel sheet excellent in high workability according to the present invention,

FIG. 2 is a diagram showing a film forming process of a lubricated steel sheet according to the present invention,

FIG. 3 is a diagram showing the relationship between the surface lubricating coating layer thickness and the strong working characteristics,

FIG. 4 is a diagram showing a relationship between a lubricant particle diameter and a surface lubricant coating layer thickness;

FIG. 5 is a diagram showing the relationship between the different particle size lubricant concentration ratio and the strong working characteristics;

FIG. 6 is a diagram showing the relationship between the concentration of dispersed particles in a lubricating coating and the workability rating,

FIG. 7 is a diagram showing the relationship between the baking time at each baking temperature and the surface lubricating coating layer thickness,

FIG. 8 is a diagram showing a relationship between baking time and strong working characteristics,

FIG. 9 is a cross-sectional view showing a coating structure of a conventional surface-treated steel sheet for press working.

[Explanation of symbols]

 1 thin steel plate 2 plating film 3 chemical conversion film 4 lubricating film 5 lubricant 6 surface lubricating coating layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsutoshi Enyama 1 Kimitsu, Kimitsu-shi, Chiba Shin Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd. (72) Ikuo Kikuchi, 1 Fuji-machi, Hirohata, Himeji-shi Hirohata Works, Nippon Steel Corporation

Claims (2)

[Claims] 1. A chromate film of Cr deposition amount 5 to 100 mg / m ² as a first layer on the surface of the plated steel sheet or coating weight 0.2 to 2.0 g / m ² of chemical conversion coating of phosphate coating, a second The sum of the ether-ester type urethane resin (a) and the epoxy resin (b) having a bisphenol type skeleton, an ester skeleton and a carboxyl group as a layer (a +
b) is 50 to 85% by weight based on the total solid content, 10 to 40% by weight of the polyolefin wax (c), and a particle size of 3 to 30.
thickness of the lubricating layer of 1.0 to 5 obtained by applying and baking a water-based lubricating paint containing 10 to 40% by weight of silica (d) of 10 nm.
μm, and particles of lubricant of 1 μm or less in the lubricating layer 20 to
60%, 2 μm or more and 80 to 40% are contained, and the particle concentration is dispersed to 10 to 40%.
A lubricated steel sheet excellent in high workability, characterized by being provided with a surface lubricant coating layer thickness of 0.4 to 1.5 μm as a layer. ^2. A chemical conversion coating of a chromate coating having a Cr deposition of 5 to 100 mg / m ² or a phosphate coating having a deposition of 0.2 to 2.0 g / m ² as a first layer on the surface of a plated steel sheet, and a second coating. The sum of the ether / ester type urethane resin (a) and the epoxy resin (b) having a bisphenol type skeleton, an ester skeleton and a carboxyl group as the layer (a +
b) is 50 to 85% by weight based on the total solid content, 10 to 40% by weight of the polyolefin wax (c), and a particle size of 3 to 30.
After applying a water-based lubricating paint containing 10 to 40% by weight of silica (d) of 10 nm, baking plate temperature is 120 ° C. or more, baking time is 10 seconds or more, and lubricant particles are 1 μm or less 20 to 60% in the lubricating layer. 2 μm or more of 80 to 40% and having a particle concentration of 10 to 40% dispersed, and baked on the lubricating layer so that the surface lubricant coating layer has a thickness of 0.4 to 1.5 μm. And a method for producing a lubricated steel sheet having excellent high processing characteristics.