JP2938305B2 - Low-gloss black-plated steel sheet with excellent lubricity and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a household electric appliance which is used without removing a coating after being pressed without using a press oil.
The present invention relates to a low-gloss black surface-treated steel sheet used for components such as building materials and automobiles.

[0002]

2. Description of the Related Art As a prior art, a black steel plate is formed by etching a zinc-nickel alloy plating with an oxidizing acid (Japanese Patent Laid-Open No.
-291981) or anodic oxidation (Japanese Unexamined Patent Publication No.
JP-A-110798) or a black film deposited from a nitric acid-containing zinc-nickel alloy solution (JP-A-2-7854).
No. 0 publication), a chromate treatment, and a resin coating composed of a resin and silica are coated thereon to produce a black-plated steel sheet.

[0003]

The black plated steel sheet needs oil for pressing. However, with the ban on the production of trichloroethane and CFCs to remove oil, lubrication performance that does not require oil is required. The appearance is lightness 20
There are demands for the following uniform black appearance and low gloss (30 or less at 60 degree gloss). It was difficult to solve both of these problems with a conventional black-plated steel sheet. The present invention has a lubricating performance that is excellent in high-speed deep drawing, overhanging, flange forming and bending workability, and is excellent in versatility with little deterioration of a film due to processing. And a method for producing the same. In particular, this technology is excellent in the present resin coating on a black plated steel sheet with a glossy cathodic electrolytic black coating excellent in productivity and corrosion resistance.

[0004]

[Means for Solving the Problems]

(1) A metal oxide or sulfide black compound or a compound black compound film of a compound and a metal having a thickness of 500 to 5000 mm is formed on the zinc alloy plating surface and Cr is formed on the zinc alloy plating surface.
A chromate film with an adhesion amount of 5 to 100 mg / m ² , and the total (a + b) of the ether / ester type urethane resin (a) and the epoxy resin (b) is 40 to the total solid content in the uppermost layer.
An aqueous lubricating resin film containing 85% by weight, 3 to 30% by weight of a lubricant (c) and 0 to 40% by weight of a silica (d) in a thickness of 0.2 to 5 μm, has a brightness of 20 or less, and has a dynamic friction coefficient A low-gloss black-plated steel sheet having excellent lubricity of 0.15 or less and 60-degree gloss of 30 or less.

(2) A coating of a metal oxide or sulfide black compound or a compound black compound of a metal and a black compound having a thickness of 500 to 5000 ° on a zinc alloy plating surface, and a Cr adhesion amount of 5 to 100 mg / m 2 on the zinc alloy plating surface. ² , the sum total (a + b) of the ether / ester type urethane resin (a) and the epoxy resin (b) is 40 to 85% by weight based on the total solid content, and the lubricant (c) is 3 to 20 in the uppermost layer.
%, Particle size silica (d) is 0 to 40% by weight, and carbon black (e) is 40 to 40% or less. 0.15 or less, low gloss black plated steel sheet with excellent lubricity of 60 degree gloss 30 or less.

(3) A zinc alloy-plated steel sheet is etched, anodized or cathodicly treated in an oxidizing aqueous solution to form a black compound of metal oxide or sulfide or a compound black compound of the compound and the metal on the surface. After that, a chromate treatment is performed, and a total sum (a) of the ether / ester type urethane resin (a) and the epoxy resin (b) is obtained.
+ B) is a water-based lubricating paint containing 40 to 85% by weight based on the total solid content, 3 to 30% by weight of lubricant (c), and 0 to 40% by weight of silica (d) having a particle size of 3 to 30 nm. A coating thickness of 0.2 to 5 μm is applied, and a reached plate temperature of 80 to
A method for producing a low-gloss black-plated steel sheet having excellent lubricity, comprising baking at 200 ° C. and then forcibly cooling.

(4) A zinc alloy-plated steel sheet is etched or anodized or cathodicly treated in an oxidizing aqueous solution to apply a black compound of a metal oxide or sulfide or a compound black compound of the compound and a metal to a zinc alloy-plated surface. After the formation, a chromate treatment is carried out, and the sum (a + b) of the ether / ester type urethane resin (a) and the epoxy resin (b) is 40 to 85 with respect to the total solid content.
% By weight, 3 to 20% by weight of the lubricant (c), particle size of 3 to 30
An aqueous lubricating paint containing 0 to 40% by weight of silica (d) and 40% or less of carbon black (e) in a thickness of 0.2 to 5 μm as a dry film thickness, and a final plate temperature of 80 to 2
A method for producing a low-gloss black-plated steel sheet having excellent lubricity, comprising baking at 00 ° C. and forcibly cooling.

[0008]

The non-delaminated type lubricated steel sheet of the present invention which can be omitted from press oil has a coating structure shown in FIG. That is, it has a coating structure composed of a plating coating (B), a black coating (C), a chromate coating (D), and a lubricating coating (E) on a thin steel plate (A). Each film can have a different configuration of the film thickness on both sides, one side, or both sides, and the composition of the film, depending on the application. The plating film A is, for example, a Zn alloy plating, the black film C is a black oxide, sulfide or a composite of these and a metal, the chromate film D is Cr 5 to 100 mg / m ² ,
The lubricating coating E is made of resin, silica, lubricant and carbon 0.2 to
It is made of 5.0 μm. Further, the present invention is basically applicable to all thin steel sheets, that is, zinc-based alloy-plated steel sheets such as aluminum-killed steel sheets, ultra-low carbon steel sheets, and high-strength steel sheets. It is advantageous to control the roughness of the steel sheet to reduce the gloss.

An example of the manufacturing process of the present invention will be described below. Steel plate → Zinc alloy plating → Washing → Black → Water washing → Chromate → Resin coating → Baking → Cooling → Drying The plating type is a zinc alloy plated steel sheet obtained by electroplating, hot dipping, or vapor phase plating. The present invention is particularly effective for an alloy plated steel sheet of zinc and an iron group (nickel, cobalt, iron). The amount of plating need not be particularly limited, and a commonly used plated steel sheet can be used. A black coating is formed on the surface of the above-mentioned plated steel sheet (coil). The method of obtaining a black film is etching using an oxidizing aqueous solution,
A black film deposited by anodic oxidation or cathodic electrolytic treatment can be used.

That is, a plated steel sheet in which a black coating of nickel oxide and phosphate is formed by etching an alloy plated steel sheet of zinc and an iron group such as nickel with an acid solution of an oxidizing acid such as nitric acid and phosphoric acid, or A black oxide is formed by electrolysis in an aqueous solution of nitrate or sulfate using a steel plate coated with zinc and an iron group such as nickel as an anode. Also nitrates,
A method of depositing a black composite plating of a metal, an oxide, and a sulfide by electrolyzing a steel plate of an alloy of zinc and an iron group, for example, nickel, as a cathode in an acidic plating solution to which a sulfite is added may be mentioned.

In particular, a black film deposited by cathodic electrolysis has excellent corrosion resistance because it does not cause cracks in plating.
Although it is excellent in productivity, a glossy appearance can be obtained as compared with others, so that the compounding with the resin film of the present invention having low gloss and excellent lubricity is effective. When the composition of the black film is analyzed by ESCA, the etched and anodized films are mainly composed of an oxide of an iron group metal during plating, and have a thickness of 100 to 3000 ° in terms of silica based on measurement of oxygen by Auger.
In the cathodic electrolysis, the thickness of the composite film is mainly 100 to 5000 ° in terms of silica based on the measurement of oxygen and sulfur by Auger, as a composite film mainly containing a hydrated oxide or sulfide of zinc and an iron group metal.

After the blackening treatment, the film is washed with water and a chromate film is immediately formed. Chromate is electrolytically reduced using a plated steel sheet as a cathode in a bath containing anions such as chromic acid and sulfuric acid, and further inevitably or if necessary, containing a metal ion. Rinse-type electrolytic chromate, an etching chromate treatment method of immersing or spraying with a chromate solution composed of chromic acid and mineral acid and then washing with water to form a chromate film, applying the chromate solution by the existing method, drying and washing with water Instead, a coating type chromate that covers the chromate film can be adopted. The amount of chromate attached 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.

The paint for a lubricating coating of the present invention will be described below. The paint of the present invention is constituted as a component to which a resin and, if necessary, a silica and a carbon black are added. The resin used in the present invention is a water-dispersible ether / ester type urethane resin (a) having a molecular weight of 3,000 or more, having a bisphenol type skeleton and an ester skeleton and having a carboxyl group, and a water soluble or water having a glycol skeleton or a bisphenol skeleton. Dispersible epoxy resin (b)
(A) in a ratio that causes 20 to 100% of the carboxyl groups to react. Resin is extremely important for the film properties aimed at by the present invention.

That is, in order to satisfy high workability and chemical durability, it is important that the adhesion, the coating strength and the elongation are balanced. By blending a urethane resin and an epoxy resin having a higher molecular weight than a film obtained by crosslinking a low molecular weight resin, a film excellent in the above properties can be obtained. Urethane resin with high molecular weight contributes to the strength and ductility balance and abrasion resistance of the coating, and epoxy resin contributes to adhesion, coating strength, and chemical durability, and the combination of both provides excellent workability and corrosion resistance. A coated film is obtained. A resin having a large molecular weight is advantageous for further improving the balance between the strength and the ductility of the coating, and the balance between the hard segment and the soft segment and the crosslink density of the resin are important.

The polyester component of urethane is flexible,
The polyether has toughness and the weight ratio of the urethane resin polyether / polyester is from 10/90 to 70/3.
It is preferred to be in the range of 0. The compounding amount of the epoxy resin (b) is 20 to 20 of the carboxyl groups of the urethane resin (a).
Most preferred is a composition in which 100% is reacted.

Examples of the polyether polyol having a urethane resin skeleton 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 gives good results. 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.

Examples of the isocyanate group for linking the ester skeleton and the ether skeleton of the urethane resin include monomers, dimers and trimers of aromatic diisocyanates such as tridiisocyanate and xylylene diisocyanate, and polyether polyols and polyester polyols. Reactions and mixtures with can be used. As for the compounding amount, the ratio to the molecular weight of the polyether polyol or polyester polyol used and the carboxyl group-introducing component described later is preferably 5 to 20% by weight of the urethane resin in terms of NCO because of excellent processing characteristics.

The carboxyl group is a functional group for self-emulsification and is necessary for obtaining adhesion to the metal surface. The carboxyl group-introducing component is a compound containing two or more hydroxyl groups or amino groups and one or more carboxyl groups, and 2,2-dimethylolacetic acid,
Examples thereof include dihydroxycarboxylic acids such as 2,2-dimethylolpropionic acid and 2,2-dimethylolpentanoic acid, and diaminocarboxylic acids such as lysine and arginine. The carboxyl group compound is polymerized with an isocyanate compound in combination with the aforementioned polyether polyol or polyester polyol. According to this method, an ether / ester type urethane resin having a carboxyl group having a molecular weight of 3000 or more can be obtained. The amount of the carboxyl group is preferably from 10 to 50 as an acid value per urethane solid. When the acid value is less than 10, the adhesion of the obtained film is insufficient, and when the acid value is more than 50, water resistance and alkali resistance are undesirably lowered.

The urethane resin having a molecular weight of 3,000 or more is necessary in order to obtain a coating excellent in balance between strength and ductility and excellent in workability, corrosion resistance and the like by blending with an epoxy resin described later. A method of dispersing a urethane resin in water is to neutralize a carboxyl group with an alkali such as ammonia or an amine and self-emulsify, or emulsify using an emulsifier.

The epoxy resin will be described below. The workability and corrosion resistance cannot be obtained with the urethane resin alone, and an epoxy resin is used. As the epoxy resin, those having a reactive hydroxyl group or epoxy group can be used. In particular, a water-soluble epoxy such as a glycol skeleton or a water-dispersible epoxy resin having a bisphenol A skeleton is preferable. The compounding amount is desirably such that 20 to 100% or more of the carboxyl groups of the urethane resin react. If it is less than 20%, the effect of the epoxy added, that is, the chemical resistance and corrosion resistance are insufficient, and the adhesion is also affected. If it exceeds 100%, the properties of a free epoxy resin as a plasticizer appear and the workability is reduced, which is not preferable. The compounding amount is compounded according to the following formula. Epoxy solid content weight (g) = acid value of urethane resin × [(1
/ 56) / 1000] x epoxy equivalent x urethane resin compounding amount (g)

Hereinafter, the lubricant will be described. In the present invention, a specific lubricant is contained in order to obtain lubricity and low gloss appearance. Lubricants are fluorine, hydrocarbon, fatty acid amide,
Ester-based, alcohol-based, metal soap, inorganic-based lubricants and the like can be used. Among them, polyolefin wax provides the best lubricity and matte appearance. Above all, the softening point is 70-160 ° C, and the particle size is 0.1-
The best results are obtained with polyethylene having a spherical branched structure of 10 μm. When the particle size is less than 0.1 μm, the appearance becomes glossy, and when the particle size exceeds 10 μm, the scratch resistance decreases, which is not preferable.

The oxidized polyethylene which does not require an emulsifier has excellent overcoating properties, and a substance having an acid value of 30 or less can provide good results. The amount of the lubricant to be added depends on the purpose, but from the viewpoint of lubricating properties, in the case of polyethylene, 3 to 30% by weight is contained in the coating. If it is less than 3%, a practically low coefficient of friction and low gloss cannot be obtained. On the other hand, if it exceeds 30%, workability and corrosion resistance are reduced. The most preferred concentration range is 5 to 20% by weight in the coating.

Hereinafter, silica will be described. Silica is incorporated in the coating in an amount not exceeding 40% by weight, if necessary, in order to improve corrosion resistance and impart strength and hardness of the coating. When carbon black is not added, better results are obtained when it is added in the range of 10 to 40%. If it is less than 10%, the strength of the coating film is insufficient, and press debris tends to be generated by the press. In addition, the corrosion resistance, which is highly dependent on silica, is insufficient. 4
If it exceeds 0%, the elongation of the coating film is reduced, and the deep drawing performance is insufficient. The most preferred silica concentration range is from 10 to 30% by weight. The silica preferably has a particle size of 3 to 30 nm. 3
In nm, the paint is easily gelled. If it exceeds 30 nm, the gloss decreases but the friction coefficient increases, and the pressability and scratch resistance deteriorate. The silica used in the present invention may be a liquid phase silica sol produced by removing sodium by ion exchange method from water glass and a gas phase silica obtained by thermally differentiating silicon tetrachloride. Liquid phase silica sol in which a small number of particles are independently and uniformly dispersed is the most excellent.

Hereinafter, carbon black will be described.
Carbon black has the effect of lowering lightness and gloss and suppressing uniformity of appearance and increase in lightness after processing. The addition amount is preferably 1 to 20% as carbon, and the sum with silica is 10 to 50%, preferably 20 to 40% in terms of nonvolatile components.
% Is desirable. If the carbon black content is less than 1%, the above-mentioned effects are not obtained. On the other hand, if the sum of silica and carbon is more than 50%, the extension of the coating film is insufficient and the pressability and scratch resistance are reduced due to an increase in the coefficient of friction. The particle size of the carbon black is desirably 50 to 200 nm, and it is desirable to use a disperse in which a small amount and a resin are dispersed in advance.

As the other additives, general matting agents such as surfactants, thickeners, coloring agents, antifoaming agents, fungicides, and dispersants can be used in the present invention. In particular, melamine cyanurate, beads, silica and the like can be used as the matting agent. When a surfactant is added, the acetylene glycol-alcohol surfactant having a mole number of added ethylene oxide of 0 to 20 is added to the paint in an amount of 0.05 to 0.05%.
When a thickener is added for adjusting the viscosity at the time of coating, a Newtonia type thickener having an ether and urethane skeleton is used in an amount of 0.01 to 0.2% based on the solid content.
The desired effect can be obtained by adding weight%.

As a coating method, an existing method such as a roll coating method, a dipping method, an air knife squeezing method, a groove roll method, a curtain coating method, etc. can be adopted, but film thickness control, film thickness accuracy and uniform appearance can be obtained. Easy reverse roll coating is most desirable. The coating amount is 0.2 as dry film thickness.
Immediately after application of ５5 μm, hot air, far-infrared furnace, electric furnace, combustion furnace, induction heating and plate temperature of 80 to 200 ° C., preferably 120
After baking at ~ 160 ° C, the mixture is forcibly cooled by a method such as water cooling, dried and wound up.

The reason for limiting the range of the film thickness from 0.2 to 5 μm is that if it is less than 0.2 μm, the lubricity, workability and corrosion resistance aimed at by the present invention are insufficient. If it exceeds 5 μm, welding cannot be performed, and problems such as blocking are likely to occur. The reason for limiting the baking sheet temperature is that if the temperature is lower than 80 ° C, the reflow and cross-linking reaction of the resin are insufficient, resulting in a film with many defects on the rough surface. If the temperature exceeds 200 ° C, the resin and the lubricant polyolefin are subject to thermal decomposition and thermal oxidation. Deteriorates. The most desirable uniform and smooth defect-free coating due to melting and crosslinking of the resin, moderate surface concentration of the lubricant and uniform dispersion in the coating are obtained in the range of 120 to 160 ° C.

[0028]

Embodiments will be described below. Example 1 A cold-rolled steel sheet having a thickness of 0.8 mm was subjected to zinc-nickel alloy plating at a plating amount of 20 g / m ^{2 in} an existing sulfuric acid-acid zinc-nickel alloy plating bath, washed with water, and then subjected to cathodic electrolytic black treatment (black coating thickness: 3000 mm). Then, apply chromate (Cr20mg
/ M ² ). Then, a predetermined amount of polyethylene wax and a predetermined amount of polyethylene wax and a Teflon lubricant were added as lubricants at a constant solid content of 20% silica and 17% carbon black, and a lubricating paint of Table 1 was applied by a reverse roll coater. + In a heating step of an electric furnace, the sheet was heated to a sheet temperature of 130 ° C and then water-cooled to produce a black lubricated steel sheet. The content (%) of the lubricant in the coating is plotted on the horizontal axis, and FIG.
4 shows the gloss on the vertical axis, FIG. 4 shows the dynamic friction coefficient on the vertical axis, and FIG. 5 shows the result of the cylindrical drawing on the vertical axis. The symbols in the figure are as shown in Table 2.

The lightness result (FIG. 2) will be described. When the resin film thickness is 1 μm, the film containing no lubricant has a low brightness (14), but both the polyethylene lubricant and the Teflon lubricant have 10, 15
%, It increases to around 17-18, but 20 or less can be secured. The resin film thickness of 2 and 3 μm is as good as 16. The matting additive rises further up to around 19. The gloss result (FIG. 3) is described. When the resin film thickness is 1 μm, the film containing no lubricant has a high gloss of 35. The addition of a lubricant reduces the gloss, giving a matte appearance with a gloss of 25 with a polyethylene lubricant of 15% and a gloss of 25 with a 15% Teflon lubricant. A film thickness of 2 and 3 μm is also good. The effect of the matting agent can be greatly reduced to a gloss of 14.

The result of the dynamic friction coefficient (FIG. 4) will be described. When the film thickness is 1 μm, the coefficient of kinetic friction is as high as 0.17 when no lubricant is used. The dynamic friction coefficient was 0.08, which was a good result, when 10% of polyethylene was contained. For a film thickness of 2 and 3 μm, the dynamic friction coefficient is set to 0.
06. The Teflon lubricant contains 10% and has a dynamic friction coefficient of 0.09, which is slightly higher than polyethylene. Film thickness 2
And at 3 μm the dynamic friction coefficient is reduced to 0.075.
Good results were obtained with little effect of the matting agent.

The result of the cylindrical drawing (FIG. 5) will be described. The effect of the film thickness of the resin film was great, and good results were shown with polyethylene, Teflon additive 2 and 3 μm. At a film thickness of 1 μm, galling was severe and the appearance was whitened without a lubricant, and necking occurred. When the sample containing the polyethylene lubricant was added in an amount of 2 to 15% including a matting agent, slight galling was observed, but a practical level appearance was obtained. Teflon has an additive effect, but is more whitened and galling than polyethylene lubricant. Corrosion resistance of all samples was salt spray test 5
No white rust was observed at 00 hours. The Erichsen adhesion was good without any peeling. The scratch resistance was excellent at evaluation point 3 with little influence of the lubricant, and decreased to evaluation point 2 although matting was at a practical level. The processing conditions described in the examples were performed under the conditions shown in Table 3 unless otherwise specified, and the processing was performed according to Tables 1, 4 and 6 unless otherwise specified.
Carried out.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

The evaluation was performed as follows unless otherwise specified. (1) Lightness: Lightness (L value) was measured with a commercially available color difference meter. (2) Gloss: Measured with a 60-degree gloss meter using black glass as a standard plate. (3) Black film thickness: It was measured from the change in intensity by Auger. Plating and Cr were measured by X-ray fluorescence. The thickness of the resin film was measured by a sectional microscope. When SiO ₂ was contained in the coating film, the film thickness was converted from the fluorescent X-ray intensity and measured. (4) Coefficient of dynamic friction: A load of 100 is applied to a steel ball having a diameter of 10 mm.
g and move at 100mm / min to move in horizontal direction (F)
Was measured with a load cell, and expressed as dynamic friction coefficient (μ) = F / 100.

(5) Cylinder deep drawability: Cylinder (50 mmφ,
The die was pressed with a die R of 5 mm, a cushion pressure of 500 kg, a clearance of 1.4 mm, and a draw ratio of 2.3, and the side surface appearance was evaluated and scored. Rating ：: The blackness of the side is good enough with few remaining scratches. △:
Black on the side is dropped, but practical level debris is adhered, and X: galling is large and black is significantly reduced. (6) Adhesion: A 9 mm drawn convex surface was tape-peeled with Erichsen, and evaluated with peeling (x) and without (o). (7) Corrosion resistance: The test time (hour) at which 5% of white rust was generated in the salt spray test. (8) Scratch resistance: A load was continuously applied with a sapphire needle having a tip diameter of 20 μm, and the load was visually observed and evaluated. Rating 3 points> 10g 2 points <5-9g 1 point <3g

Example 2 The same plating, black coating and chromate-treated black-plated steel sheet as in Example 1 were prepared by mixing a predetermined amount of carbon black with a solid content of 15% for polyethylene wax and 20% for silica. Was applied with a reverse roll coater, heated to a sheet temperature of 150 ° C. in a COG combustion furnace (900 ° C.), and then cooled with water to produce a black lubricated steel sheet.
The abscissa represents the content (%) of carbon black in the coating, FIG. 6 shows the brightness on the ordinate, FIG. 7 shows the gloss on the ordinate, FIG. 8 shows the dynamic friction coefficient on the ordinate, and FIG. The results are shown.
The symbols in the figure are as shown in Table 5.

The result of the brightness (FIG. 6) will be described. When the resin film thickness is 1 μm, the film containing no carbon exhibits a lightness of 19 to 20 and is improved around 18 by adding 5 and 10% of carbon. Even at a resin film thickness of 2 and 3 μm, the same brightness as 1 μm was obtained. Matte addition is 20% with 10% carbon
It goes up to the practical range. The gloss result (FIG. 7) is described. When the resin film thickness is 1 μm, the film containing no lubricant has a gloss of 28. Addition of carbon gives 5% gloss 21,10
%, The gloss can be reduced to 16 and improved. As for the film thickness, the effect of lowering the gloss was recognized.
It becomes 6. By adding carbon, the gloss can be further reduced, by adding 5% of carbon, the gloss can be improved to 19 for 2 μm and for 3 μm to 16 and by adding 10% of carbon, the gloss can be improved to 11 for both 2 and 3 μm. The effect of the matting agent is large, and can be reduced to a gloss of 8 even with a resin film thickness of 1 μm.

The results of the dynamic friction coefficient (FIG. 8) will be described. At a film thickness of 1 μm, the coefficient of kinetic friction is 0.1 without carbon, which is good. The dynamic friction coefficient is slightly increased to 0.11 when the carbon content is 5%, and is 0.12 when the carbon content is 10%, which is a practical level. The coefficient of kinetic friction at a thickness of 2 μm is 0.075 without carbon, 0.08 at 5% carbon, and 10 carbon
% Is improved to 0.085. Good results were obtained with little effect of the matting agent. The dynamic friction coefficient at a film thickness of 3 μm is further improved to 0.07 without carbon, 0.075 with 5% carbon, and 0.08 with 10% carbon. The effect of the matting agent is negligible with the addition of 10% carbon.

The result of the cylindrical drawing (FIG. 9) will be described. The effect of the thickness of the resin film was large, and good results were obtained at 2 and 3 μm. At a film thickness of 1 μm, good results of evaluation points Δ to ○ were obtained without a lubricant. Although the score decreases to 5 when carbon 5 and 10% are added, it is a practically usable level. Practical appearance was obtained even with a matting agent. No corrosion was observed in any of the samples in the salt spray test for 500 hours. The Erichsen adhesion was good without any peeling. The scratch resistance was excellent at evaluation point 3 with little influence of the lubricant, and decreased to evaluation point 2 although matting was at a practical level.

[0041]

[Table 4]

[0042]

[Table 5]

Example 3 The same plating, black coating and chromate-treated black-plated steel sheet as used in Example 1 were applied to polyethylene 13 at a solid content ratio.
%, Carbon black 10% constant, a predetermined amount of silica was added and the lubricating paint of Table 6 was applied to a dry film thickness of 2 μm with a reverse roll coater, and the sheet temperature was raised to 120 ° C. in a heating process using hot air and an electric furnace. After heating, the resultant was cooled with water to produce a black lubricated steel sheet. The silica content (%) in the coating is plotted on the horizontal axis, FIG. 10 shows the brightness on the vertical axis, FIG. 11 shows the gloss on the vertical axis, FIG. 12 shows the dynamic friction coefficient on the vertical axis, and FIG. FIG.
The vertical axis indicates the results of corrosion resistance.

The result of the brightness (FIG. 10) will be described. Silica has almost no effect on lightness.
7 were obtained. The gloss result (FIG. 11) will be described. Silica-free coatings improve to 20 gloss at 20 and 30% to 20 gloss when silica is added. The results of the dynamic friction coefficient (FIG. 12) will be described. Without silica, 0.07 dynamic friction coefficient, 0.08 with 20% silica, silica 3
At 0%, the value slightly increased to 0.09, but good results were obtained in each case.

The result of the cylindrical drawing (FIG. 13) will be described. A slight galling was observed without silica, but a practical level of appearance was obtained. Very good results were obtained with 20% silica.
Although a slight galling of 30% of silica was recognized, a practically usable result was obtained. The results of the corrosion resistance (FIG. 14) will be described. The effect of the addition of silica was clearly observed, and the white rust generation time was 450 hours without silica, 750 hours with 20% silica,
It improved to 1000 hours with 30% silica. Ericksen adhesion was good without any peeling. With respect to scratch resistance, no silica was obtained, and 20% showed an evaluation point of 3;

[0046]

[Table 6]

Example 4 A cold rolled steel sheet having a thickness of 0.8 mm was subjected to zinc nickel alloy plating at a plating amount of 20 g / m ^{2 in} an existing sulfated acidic zinc nickel alloy plating bath, washed with water, and then subjected to an etching black treatment (black coating thickness). After 1500Å), electrolytic chromate (Cr40m
g / m ² ). Subsequently, the lubricating paint of Table 6 prepared by adding 13% of polyethylene, 10% of carbon black and 20% of silica in a solid content ratio was applied to a dry film thickness of 1 μm by a reverse roll coater, and heated in a hot air + electric furnace heating step. After heating to a sheet temperature of 120 ° C. and water cooling, a black lubricated steel sheet was manufactured. Good results with a lightness of 16, a gloss of 20, and a dynamic friction coefficient of 0.09 were obtained. In the case of a cylindrical press, the rating is reduced to Δ △ ×, and the use is limited. As for the corrosion resistance, white rust was generated in 100 hours, and it was necessary to pay attention to the application, but a usable result was obtained for home appliances.

Example 5 A hot-dip galvanized steel sheet having a thickness of 0.8 mm and a thickness of 40 g / m ² was subjected to cathodic electrolysis black treatment (black coating thickness: 2000 mm) and then coated with chromate (Cr 20 mg / m 2).
² ) did. Subsequently, silica 20 was added at the solid content ratio shown in Table 1.
%, Carbon black 10%, lubricating paint of polyethylene wax 15% as a lubricant is applied by a reverse roll coater with a dry film thickness of 3 μm, and heated to a sheet temperature of 130 ° C. in a heating process of hot air and an electric furnace, followed by water cooling. A black lubricated steel plate was manufactured. Brightness 17, gloss 10, dynamic friction coefficient 0.1
A good result of 0 and a cylindrical drawing score of 3 was obtained.

[0049]

The most significant advantage of the present invention is that it can provide a black steel sheet that does not require chlorofluorocarbon or triethane, which causes destruction of the ozone layer. Further, since no press oil is used, the working environment can be improved. In terms of quality, it has press characteristics equal to or higher than that of press oil, can be used for deep drawing and bending at high speed, and can be used as it is without removing the coating to obtain corrosion resistance, welding, chemical resistance, and topcoat paintability. Therefore, it can be widely applied to home appliances, building materials and automobile parts. In addition, since the production equipment does not contain any organic solvent, the production can be carried out on an existing plating line in terms of equipment, so that production can be performed at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a film configuration of the present invention,

FIG. 2 shows the effect of adding polyethylene wax and Teflon as a lubricant to a resin obtained by adding 10% of carbon black and 20% of silica to the urethane epoxy resin of the present invention, and plotting the content (%) of the lubricant in the coating on the horizontal axis. A diagram with the brightness on the vertical axis,

FIG. 3 is a graph showing the relationship between the effect of the same coating as in FIG. 2 and gloss on the vertical axis.

FIG. 4 is a graph showing the relationship between the effect of the same coating as in FIG. 2 and the dynamic friction coefficient on the vertical axis;

FIG. 5 is a diagram showing the effect of the same coating as in FIG.

FIG. 6 is a graph showing the effect of adding carbon black to 15% of polyethylene wax and 20% of silica to the urethane epoxy resin of the present invention, wherein the carbon black content (%) in the coating is plotted on the horizontal axis and the lightness is plotted on the vertical axis. ,

FIG. 7 is a graph showing the relationship between the effect of the same coating as in FIG. 6 and gloss on the vertical axis.

FIG. 8 is a graph showing the relationship between the effect of the same coating as in FIG. 6 and the dynamic friction coefficient on the vertical axis;

FIG. 9 is a diagram showing the relationship between the effect of the same coating as in FIG. 6 and a cylindrical press on the vertical axis.

FIG. 10 shows the effect of adding silica to a resin paint containing 13% of polyethylene wax and 20% of carbon black to the urethane epoxy resin of the present invention, in which the silica content (%) in the coating is plotted on the horizontal axis and the lightness is plotted on the vertical axis. Figure,

FIG. 11 is a diagram showing the relationship between the gloss and the effect of the same coating as in FIG. 10 on the vertical axis.

FIG. 12 is a graph showing the relationship between the effect of the same coating as in FIG. 10 and the dynamic friction coefficient on the vertical axis,

FIG. 13 is a diagram showing the effect of the same coating as in FIG.

FIG. 14 is a graph showing the relationship between the effect of the same coating as in FIG. 10 and the salt spray corrosion resistance time on the vertical axis.

[Explanation of symbols]

 A Thin steel plate B Plating C Black coating D Chromate coating E Lubricating coating

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C23F 1/30 C23F 1/30 (72) Inventor Katsutoshi Enyama 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Corporation Inside Kimitsu Works (72) Inventor Kazumi Shibata 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Corporation Kimitsu Works (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 28/00

Claims (4)

(57) [Claims] 1. A coating of a black compound of a metal oxide or sulfide or a composite black compound of a compound and a metal having a thickness of 500 to 5000 mm on a zinc alloy plating surface, and a Cr adhesion amount of 5 to 100 mg / m ² on the zinc alloy plating surface. Chromate coating, ether-ester type urethane resin on top layer (a)
Aqueous lubrication containing the sum of (a + b) and epoxy resin (b) of 40 to 85% by weight based on the total solid content, 3 to 30% by weight of lubricant (c), and 0 to 40% by weight of silica (d). A low-gloss black-plated steel sheet having a resin coating having a thickness of 0.2 to 5 μm, a lightness of 20 or less, a dynamic friction coefficient of 0.15 or less, and a luster of 60 degrees or less of 30 or less. 2. A coating of a black compound of a metal oxide or sulfide or a composite black compound of said compound and a metal having a thickness of 500 to 5000 ° on a zinc alloy plating surface, and a Cr adhesion amount of 5 to 100 mg / m ² on the zinc alloy plating surface. Chromate coating, ether-ester type urethane resin on top layer (a)
And the total amount of epoxy resin (b) (a + b) is 40 to 85% by weight based on the total solid content, lubricant (c) is 3 to 20% by weight, particle size silica (d) is 0 to 40% by weight, carbon An aqueous lubricating resin film containing black (e) of 40% or less having a film thickness of 0.2 to 5 μm, having a lightness of 20 or less, a kinetic friction coefficient of 0.15 or less, and a lubricity of 60 ° or less of 30 or less. Bright black plated steel sheet. 3. A zinc alloy-plated steel sheet is etched or anodized or cathodicly treated in an oxidizing aqueous solution to form a black compound of a metal oxide or sulfide or a compound black compound of the compound and a metal on the surface. rear,
After chromate treatment, the sum of the ether / ester type urethane resin (a) and the epoxy resin (b) (a +
b) dries an aqueous lubricating paint containing 40 to 85% by weight based on the total solid content, 3 to 30% by weight of a lubricant (c), and 0 to 40% by weight of silica (d) having a particle size of 3 to 30 nm. A coating thickness of 0.2 to 5 μm is applied, and a reached plate temperature of 80 to
A method for producing a low-gloss black-plated steel sheet having excellent lubricity, comprising baking at 200 ° C. and then forcibly cooling. 4. A zinc alloy-plated steel sheet is etched or anodized or cathodicly treated in an oxidizing aqueous solution to apply a black compound of a metal oxide or sulfide or a compound black compound of said compound and a metal to the surface of the zinc alloy plating. After forming, chromate treatment is performed and ether
The sum (a + b) of the ester type urethane resin (a) and the epoxy resin (b) is 40 to 85% by weight based on the total solid content,
3 to 20% by weight of a lubricant (c), 0 to 40% by weight of silica (d) having a particle size of 3 to 30 nm, and carbon black (e)
Is applied in an amount of 0.2 to 5 μm as a dry film thickness, and the ultimate plate temperature is 80 to 200 ° C.
A method for producing a low-gloss black-plated steel sheet having excellent lubricity, characterized by forcibly cooling after baking.