JPH06173037A - Non-defilm type lubricating coating steel plate with no use of press oil - Google Patents

Abstract

PURPOSE:To develop the non-defilm type lubricating coating steel plate with no use of a press oil having the lubricating performance excellent in processability and having on degradation in the film due to processing by applying and baking the chemical conversion film such as a chromate film and the water-based lubricating coating consisting of a specified composition on the surface of a steel plate. CONSTITUTION:The chemical conversion film 3 such as the chromate film having 5-100mg/m<2> Cr coverage or the phosphate film having 0.2-2.0g/m<2> coverage, is formed on the surface of the steel plate 1 coated with Zn plating 2. Then the water-based lubricating coating, which is the mixture of 50-85wt.% (a+b) expressed in terms of total solid matter, where (a) is a water-based ether-ester type urethane resin having a bisphenol type skeleton, an ester skeleton and carboxy group of 10-50 acid value and (b) is an epoxy resin having a glycohol skeleton or the bisphenol type skeleton, 3-30wt.% polyurethane wax(c) having 0-30 saponification value and 70-160 deg.C melting point and 10-40wt.% fine silica (d) having 3-30nm grain size, is applied on the chemical conversion film as the second layer 4, and baked, and the film having 0.2-5mum thickness is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet which is used for parts such as home electric appliances, building materials and automobiles which are used after pressing without removing a lubricating coating.

[0002]

2. Description of the Related Art Conventional parts have been manufactured by applying press oil, removing the oil after press molding. However, there is a strong need for surface-treated steel sheets with restrictions on the use of degreasing solvents, lubrication performance that allows the elimination of press oil for cost reduction, and excellent surface properties (appearance, corrosion resistance, paint adhesion, etc.) of the coating after pressing. Has become. The present invention provides an epoch-making lubricating plated steel sheet that can meet this need. Japanese Unexamined Patent Publication No. HEI 3-
Japanese Patent No. 16726 "Lubricating Resin Treated Steel Sheet With Excellent Formability"
There is. This steel sheet has a zinc-based or aluminum-based alloy-plated steel sheet with a chromate film with a Cr adhesion amount of 200 mg / m ² or less and a resin film of 0.3 to 3.0 g / m ^{2 on} the resin film. 100 parts by weight of a resin having a hydroxyl group and / or a carboxyl group, silica 1
It is stated that it is 0 to 80 parts by weight, and 20 parts by weight or less of a polyolefin wax having an average particle size of 1 to 7 μm. It is described that this lubricated steel sheet can be applied to a wide range of resin types.

However, it is not satisfactory or insufficient from the viewpoint of actual high-speed continuous crank press workability and little deterioration of the coating film after processing, and it is necessary to optimize the coating film composed of resin, silica and lubricant. Only then can a lubricating steel sheet be obtained that enables stable operation. Particularly, in the case of non-film-removing type lubricated steel sheet, the appearance and performance after processing are important, and it is necessary to consider the uniformity and extension of the thickness of the lubricating coating, compression, and sliding wear resistance.

[0004]

DISCLOSURE OF THE INVENTION The present invention has a versatile property that has a lubricating performance excellent in high-speed deep drawing by a crank press, overhanging, flange forming and bending workability, and has little deterioration of the coating film due to working. It is an object of the present invention to provide a non-film-removal type lubricated steel sheet which can omit the press oil and has excellent characteristics.

[0005]

The present invention advantageously solves the problems of the prior art. (1) The amount of Cr deposited as a first layer on the surface of a plated steel sheet is 5 to 5.
Chromate coating of 100 mg / m ² or adhesion amount of 0.
A conversion coating of a phosphate coating of ^{2 to} 2.0 g / m ² , and an aqueous ether / ester urethane resin (a) having a bisphenol skeleton, an ester skeleton and a carboxyl group as the second layer and an epoxy resin (b) The total amount (a + b) is 50 to 85% by weight, the polyolefin wax (c) is 3 to 30% by weight, and the silica (d) having a particle size of 3 to 30 nm is 10 to 40% by weight, based on the total solid content. A film thickness of 0.2-5 μm obtained by applying and baking a water-based lubricating coating
A non-film-removing lubrication plated steel sheet capable of omitting press oil, characterized by being provided with the above film.

(2) The weight ratio of the polyether skeleton to the polyester skeleton of the ether / ester type urethane resin (a) is 10:90 to 70:30, and the acid value of the urethane resin is 10 to 50. A non-film-removable lubricating plated steel sheet capable of omitting press oil according to claim 1, and (3) an epoxy resin (b) having a glycol skeleton or a bisphenol skeleton bisphenol skeleton, wherein (a) 20-100% by weight of the carboxyl group of
The non-film-removing type lubrication plated steel sheet capable of omitting press oil according to claim 1, wherein (b) is blended in a ratio that reacts with.

(4) The melting point of the polyolefin wax (c) is 70 to 160 ° C., and the particle size is 0.1 to 70 μm. . (5) The saponification value of the polyolefin wax (c) is 30.
The non-film-removal type non-film-removing lubrication plated steel sheet according to claim 1, wherein the structure is less than or equal to 0 and has a branch.

[0008]

OPERATION AND EXAMPLES The non-film-removal type lubricated steel sheet capable of omitting the press oil of the present invention has the coating structure shown in FIG. That is, it is a coating structure composed of a plating coating 2, a chromate or phosphate conversion coating 3 and a lubricating coating 4 on a thin steel plate 1. Each coating may have a different film thickness on both sides, one side or both sides, and a composition of the coating depending on the application. Further, for example, the lubricating coating is resin + silica + polyolefin wax 0.2 to 5.0 μm, and the chemical conversion coating is Cr5 to 100 mg / m ² or phosphate 0.2 to
2.0 g / m ² , plating is Zn, Zn alloy, Al, Al
Alloy plating consists of a plating amount of 1 to 200 g / m ² .
The present invention is basically applicable to all thin steel plates, that is, aluminum killed steel plates, ultra low carbon steel plates, and high tensile steel plates. Table 1 shows the compositions of typical steels to which the present invention is applied.

[0009]

[Table 1]

The plating species are zinc obtained by electroplating, hot dipping, vapor phase plating, zinc alloy plating, and multi-layer plated steel sheet, aluminum, aluminum alloy plated and multi-layer plated steel sheet. The plating amount is not particularly limited, and a commonly used plated steel sheet can be used. A chromate film or a phosphate film is used as the chemical conversion film. The chemical conversion film is located between the plated surface and the lubricating film and provides adhesion, corrosion resistance and the like during processing. Chromate is a post-water washing type electrolytic reduction chromate containing trivalent chromium hydrated oxide as a main component, and a post-water washing type etching chromate solution containing trivalent chromium and hexavalent chromium hydrated oxide as a main component is applied and dried. An anhydrous washing type coating chromate coating can be adopted. The adhesion amount is 5 to 100 mg / m ² in terms of Cr.
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 , cohesive failure of the chromate itself is likely to occur and adhesion cannot be obtained. Chromate coating is 3
It is desirable that it is difficult to dissolve in a water-based lubricating paint having a high ratio of valent chromium / hexavalent chromium.

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 0.2 to 2.0 g / m ² for reasons of corrosion resistance and adhesion. If it is less than 0.2 g / m ² , corrosion resistance cannot be obtained. If it exceeds 2.0 g / m ² , cohesive failure of the phosphate coating may result in poor adhesion due to severe processing.

The lubricating coating of the present invention will be described below.
The first feature of the present invention resides in that a proper type of resin is mixed as a base resin in a constant weight ratio. The resin must be a component having a well-balanced adhesion, elongation, shear strength, corrosion resistance, abrasion resistance, and chemical resistance. In order to satisfy these performances, the combined use of the resins of the present invention is preferable. The present inventors have already achieved blending a urethane resin and an epoxy resin, and by blending a specific polyolefin wax, to obtain strength processability and corrosion resistance. It has been found that by specifying the structure, particularly excellent performance is exhibited.

In order to achieve high workability and high corrosion resistance,
It is important that the coating film is uniform and has excellent adhesion, and that strength and elongation are well balanced. By using a urethane resin having a large molecular weight and an epoxy resin in combination, it is easier to control the basic physical properties than a film formed by cross-linking resins having low molecular weights, and the coating amount is 0.3 to 6 g / m ² It was found that even in the case of the above thin film, uniform physical properties can be easily obtained. The low-molecular-weight urethane resin is a type of resin containing various isocyanate-based crosslinking agents. As a resin, a combination of a resin system in which a urethane resin having a molecular weight of 3000 or more and having excellent abrasion resistance and an epoxy resin having excellent adhesion or film strength improvement is combined to exhibit various properties such as high workability and corrosion resistance. Is a 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 a carboxyl group, which is 0 or more, and the epoxy resin (b) is a type having a glycol skeleton or a bisphenol skeleton. , (A) are mixed at a ratio of reacting 20 to 100% of the carboxyl groups. By using the polymer urethane resin of the present invention, a 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 of cm ² or more.

Generally, the physical properties of the urethane resin are controlled by the balance between the hard segment and the soft segment and the crosslinking density, so that a wide range of properties can be controlled depending on the skeleton and the type of isocyanate. The adjustment of the elongation and tensile strength of the urethane resin used in the present invention is controlled by the contents of the ester skeleton showing flexibility, the ether skeleton showing toughness, and the urethane bond portion, and if the content of the latter is increased, the elongation is increased. Although it is small, a tough property with high tensile strength can be obtained. In order to exert particularly excellent lubrication characteristics, a urethane resin having a polyester skeleton and a bisphenol skeleton as an ether component shows particularly excellent performance, compared to a urethane resin having a polyester skeleton having a numerical value similar to the resin physical properties of the present invention. . It is easily inferred that a resin having a bisphenol skeleton with similar resin physical properties has excellent lubricating properties because not only elongation and strength of the resin but also adhesion to the base material is a major factor of lubricity. Weight ratio of polyether skeleton to polyester skeleton is 1
The range of 0:90 to 70:30 is preferable. When the ratio of the polyether is more than the above range, it is tough and has a small elongation, resulting in poor moldability.

A urethane resin system obtained by polymerizing an ether or ester polyol with an isocyanate to have a molecular weight of 3000 or more forms a self-film by heating, but a method of further improving processability, chemical resistance and corrosion resistance as coating film performance. As such, there is a method in which an epoxy resin having a reactive functional group (hydroxyl group, epoxy group, etc.) is blended and crosslinked by heating to improve the functionality. It was newly found that this method can significantly improve the processability, corrosion resistance, and chemical resistance as compared with the film formation method using only a modified product obtained by epoxy-modifying a urethane resin. This crosslinking reaction proceeds only in the combined resin system, but an isocyanate compound or amino compound called a curing agent may be blended if necessary.

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

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 weight and the ratio of the polyester polyol, the polyether polyol to be used and the carboxyl group-introducing component to be described later, but 5 to 20% by weight of the urethane resin in terms of NCO can obtain optimum processing characteristics as resin physical 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, and 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 the polyether polyol. By this method, an ether / ester type urethane resin having a carboxyl group having a molecular weight of 3000 or more, which is 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 emulsion-dispersing with an emulsifier.
As a work environment measure, it is most preferable to recover the solvent contained in the urethane production process before water-based conversion to finally obtain a solvent-free type water dispersion. The amount of the carboxyl group is suitably 10 to 50 in terms of acid value per urethane solid content. When it is less than 10, the adhesion is insufficient and the workability and corrosion resistance are poor. If it exceeds 50, the water resistance and alkali resistance are poor, and the corrosion resistance is lowered.

The epoxy resin having a reactive functional group (hydroxyl group, epoxy group, etc.) is preferably blended in such a proportion that 20 to 100% of the carboxyl groups of the urethane resin react. If it is less than 20%, the compounding effect is poor, and if it exceeds 100%, the epoxy resin acts as a plasticizer, so that the high workability is deteriorated.
Epoxy resin has a great 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 and an emulsifier-free type to prevent deterioration of coating film performance are required as environmental measures, 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 with each other in an equivalent amount, the formula for the required amount of the epoxy resin for 100% reaction with respect to the urethane resin having a predetermined acid value (AV) is It is Equation 1. (Formula 1) 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 that contributes to the adhesiveness does not correspond to the reaction, but the ring-opening of the epoxy group results in O.
Adhesion is secured because H groups are generated. In addition, the corrosion resistance is greatly improved by blending the epoxy resin. With a combination of a urethane resin having a molecular weight of less than 3000 and the above epoxy resin, stable and high processability cannot be achieved. Further, when a urethane resin having a molecular weight of 3000 or more is used alone, a high degree of workability and corrosion resistance cannot be obtained.

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 preferably 50 to 85% in terms of solid content relative to the total solid content. 50%
If it is less than 85% 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 lubricant additive for improving workability, 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 resin film formed by molding. It is necessary in order to reduce the friction between the surface of the mold and the mold and maximize the lubricating effect. That is, when the lubricant is dispersed and present in the formed resin film, the coefficient of surface friction is high, the resin film is easily broken, and the powdery substance is peeled off and deposited, resulting in poor appearance and workability called powdering phenomenon. . As the substance existing on the surface of the resin film, a substance which is incompatible with the resin and has a small surface energy is selected.

As a result of the study conducted by the present inventors, it was found that the use of the polyolefin wax greatly improves the workability and improves 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. During processing, the film temperature rises due to the deformation heat and friction heat of the material, so the melting point of the wax is 70-
160 ° C. is appropriate, and if it is less than 70 ° C., it softens and melts during processing, and excellent properties as a solid lubricating additive cannot be exhibited. Further, if the melting point is higher than 160 ° C., hard particles will be present on the surface and the friction characteristics will be deteriorated, so a high degree of 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 large polarity and are easily miscible with the resin, and are less likely to be present on the resin surface during film formation. Therefore, they cannot be said to be appropriate when a high level of processing performance is required.
Particularly preferred is a wax having a saponification value of 0 and having no ester bond having a smaller compatibility with the resin.

The particle size of these waxes is 0.1 to 7.
0 μm is suitable. A particle size of more than 7.0 μm is not preferable because the solidified wax has an uneven distribution. If it is less than 0.1 μm, the workability is insufficient. The amount of the lubricating additive is 3 to 30% in terms of solid content based on the total solid content of the lubricating coating. If it is less than 3%, the workability improving effect is small, and if it exceeds 30%,
Workability and corrosion resistance decrease.

As another additive, SiO ₂ is added in an amount of 10 to 40% with respect to the total solid content in order to improve the corrosion resistance. Addition of SiO ₂ has the effect of greatly improving corrosion resistance and improving workability. 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 is small and the corrosion resistance is lowered and the elongation and strength of the resin are lowered and the workability is lowered. Si
A suitable particle size of O ₂ is 3 to 30 μm. Three
If it exceeds 0 μm or is less than 3 μm, higher workability and corrosion resistance cannot be obtained. The types of silica include liquid phase colloidal silica and gas phase silica,
The present invention is not particularly limited. In addition, in order to improve the weldability, a conductive material or a coloring pigment material may be added to improve the design. Further, various additives such as an anti-settling agent, a leveling agent and a thickening agent may be added.

Since the present invention is a water-based paint, when a predetermined amount is applied to the surface to be coated, surface wettability is poor due to high surface tension as compared with solvent-based paint, and uniform applicability cannot be obtained. There is. In order to secure performances such as high workability and corrosion resistance, it is essential that the surface to be coated be applied uniformly. Therefore, it is known to add a wetting agent or a thickening agent. Examples of the wetting agent include known surface active agents such as fluorine type and silicon type which reduce the surface tension and reduce the surface tension. In the present invention, the number of moles of added ethylene oxide is 0 to 2 among these compounds.
Acetylene glycol / alcohol type surfactant (e) of 0 to 0.05 to 0.5 with respect to the water-based lubricating coating composition.
It has been found that it is particularly preferable that the content be%. 0.0
If it is less than 5%, the effect of addition is small, and if it exceeds 0.5%, the effect of improving wettability is saturated. Incidentally, the acetylene glycol / alcohol type surfactant is characterized in that it has a high wetting rate and simultaneously has a defoaming effect. On the other hand, fluorine-based and silicon-based surfactants are excellent in surface tension lowering ability, but are not suitable because they have a low wetting rate, poor defoaming properties, and poor topcoat adhesion.

In the case where the thickener cannot secure sufficient surface coverage with a wetting agent alone on the repelling portion of the surface to be coated, or when the coating thickness represented by a roll coater cannot secure the coating thickness. May be added as a countermeasure. Since the coating material of the present invention is usually applied to an object to be coated at high speed,
In thixotype thickeners represented by cellulosics,
The effect is small under coating conditions subject to high-speed shear stress. It is known that Newtonian type thickeners are suitable for thick coating conditions. As the thickener used in the present invention, a thickener having an ether / urethane skeleton having a molecular weight of 1,000 to 20,000 is particularly preferable.

Since this thickener is compatible with the urethane resin skeleton which is the base resin of the coating composition of the present invention, it exhibits an associative Newtonian thickening behavior, and exhibits a significant effect even when added in a small amount. Usually, when an additive is added to a paint, the original performance is often deteriorated, but this thickener has a skeleton that does not easily hydrolyze, so the effect when it remains in the coating film is very small. It is a feature. The addition amount is 0.01 to 0.2% with respect to the resin solid content of the water-based lubricating coating composition, and is usually determined by the coating conditions. If the amount is less than 0.01%, the thickening effect is small, and if the amount exceeds 0.2%, the viscosity becomes too large, which causes problems in the coating property and also reduces the high workability and excellent corrosion resistance, which is not preferable. .

FIG. 2 shows a plating amount of 20 g / m.²Electric zinc
Cr adhesion amount 50mm / m ²Etching black
Lubricant shown in Table 2 and a tree shown in Table 3 with a mate coating
A plate that is coated with a lubricating paint of a fat and silica composition and is baked in a baking oven.
Lubricate with a film thickness of 2.5 to 3.0 μm by baking at a temperature of 130 ° C
It is a press evaluation result of the lubricating steel sheet of the present invention coated with a film.
It The type of lubricant is on the horizontal axis and the pressability evaluation is on the vertical axis.
It is shown. The evaluation of pressability is a corner of 60 mm depth.
After performing a cylinder high-speed crank press, connect the side surface of the corner.
Peel it off with adhesive tape and stick it on a white paper, and measure the brightness with a color difference meter.
Calculate the difference in brightness from the standard paper with normal adhesive tape
It was A score of 6 is cracked by the press, and a score of 5 is a brightness difference of 10 or more.
Point 1 has a brightness difference of 1 or less, and grades 4 to 2 are gradually improved
It was evaluated by the standard. Also, 90% L with 5% clearance
Bending press is performed and the generated press residue is observed and scored.
Then, the flange bending process is evaluated and the black bar graph
Indicated. Is the score ◎ pressed at all on the plate side and punch?
It is a good score with no score, and score x punch and
It is not good because the press residue on the plate and the board remained linearly
The grade ○ is good because there are several presses left on the punch.
The grade Δ is a thin line remaining on the plate side
It is problematic.

The lubricating coating UF-L has a grain size of 0.
This is an example using Teflon (PTFE) with a thickness of 04 μm and a density of 2.2. The lubricating coating UF-L had a score of 5 and 5 in the square cylinder crank press, and an L bending score of x. The lubricating film UE-1 has a particle size of 5.0 μm and a density of 0.9 as a lubricant.
It is an example of the present invention using the polyethylene wax of No. 7.
This lubricating coating UE-L had a rating of 2.0 and a rating of L bending of ◯ in the square cylinder crank press. The lubricating coating UE-2 is an example of the present invention in which polyethylene wax having a particle size of 1.0 μm and a density of 0.92 is used as a lubricant. The lubricating coating UE-2 had a rating of 1.5 and an L-bending rating of ⊚ in the square cylinder crank press.

The lubricating coating UE-3 has a grain size of 0.
This is an example of the present invention using a polyethylene wax having a density of 6 μm and a density of 0.92. This lubricating coating UE-3 had a rating of 1.0 and an L-bending rating of ⊚ in the square cylinder crank press.
The reason why the pressability of UF-L is not good is that the polyolefin wax of the present invention thickens on the coating surface and lowers the friction coefficient, whereas PTFE does not thicken easily and slips in a layer structure in terms of molecular structure and peels off as a press residue. It can be estimated that it is easy to accumulate. The difference in pressability between the L-bend UE-1 and UE-3 can be estimated to be the difference in the amount of thickening of the wax on the coating surface because the density and size of the lubricant are different.

The optimum value of the lubricant in the coating film of the present invention will be described with reference to FIG. The sample has a Cr deposit of 36 mg / m
² the electrolytic chromate treatment was plated weight 20 g / m ² 1
2.5-3.0 film thickness on 2% nickel-zinc alloy plated steel sheet
It is the press result which coated the lubricating film of (mu) m. The horizontal axis represents the concentration (%) of the lubricant in the coating, and the vertical axis represents the coefficient of dynamic friction and the coefficient of static friction. Dynamic friction coefficient is 1
The force in the horizontal direction was measured by a load cell in which a 0 mm semi-steel ball was loaded with 100 g and moved at 10 mm per minute, and the force was divided by the load to obtain a friction coefficient. The static friction coefficient is 100g
The friction coefficient was calculated from the angle at which the weight of No. 2 was placed on the surface of the lubricating steel plate and the angle plate was inclined at 10 degrees per second and the weight started to slide. -○ -indicates the static friction coefficient of the present invention using polyethylene wax as a lubricant. The surface starts to decrease at about 2% and becomes a slippery surface at 0.12 at about 13%. -□-is the result of using PTFE as a lubricant, and even with the addition of 17%, the coefficient of static friction was 0.15, which was higher than that of polyethylene wax. -● -indicates the dynamic friction coefficient of the present invention using polyethylene wax as a lubricant. 1% decreased to 0.12, and 3% decreased to 0.1.
It stabilizes at a low value of 0.05 with addition of 06 and 5%. −
⋄-indicates an example in which PTFE is used as a lubricant and shows a dynamic friction coefficient of 0.12 at a content rate of 17%.

FIG. 4 shows the results of measuring the elongation and tensile strength of the lubricating coating by making a film of the lubricating coating of the present invention having a thickness of about 2 mm and conducting a tensile test. When the silica content in the coating is 10%, the elongation is 450%, tensile strength is 50 kg / cm ² , and when the silica content is 38%, the elongation is 240% and the tensile strength is 250 k.
It was good as g / cm ² . When the silica content is 50%, the elongation is deteriorated to 100%, and the tensile strength is 170 k due to film breakage
The coating property was lowered to g / cm ² and the coating properties were lowered.

For the above reasons, the use of the polyolefin wax as the lubricant improves the rectangular cylinder crank press and the L-bending score, and the polyolefin wax concentration in the coating is preferably 3 to 30% because the coefficient of friction is low and excellent. Good lubricity is obtained. When the silica content in the coating is specified to be 10 to 40%, a coating excellent in elongation and tensile strength balance can be obtained.

The thickness range of the lubricating coating of the present invention is 0.2 to
It is 5.0. The optimum film thickness varies depending on the form of the press and is difficult to limit, but a thick film is advantageous for deep drawing and a thin film is advantageous for L bending. If it is less than 0.2 μm, the lubricating performance is unstable. A length of 5.0 μm is not preferable because a large amount of coil blocking and pressed dust is generated. 4 in FIG.
The dynamic friction coefficient and the film thickness and the square cylinder crank press evaluation of the lubricating coating of the present invention obtained by coating the chromate-treated plated steel sheet of No. 2 with the lubricating coating are shown. The dynamic friction coefficient and the square cylinder crank press conditions were determined by the method described above. The rating of the square cylinder crank press is [○] when no galling occurs due to metal contact between the die and the sample, "△" when slight galling is allowed and the allowable level is acceptable, and "x" when severe galling occurs.
Is shown in the figure. In the square cylinder crank press, the film thickness of 2.0 μm or more and the dynamic friction coefficient of 0.13 or less gave good results “Δ to ◯”. Further, when the dynamic friction coefficient is 0.15 or more and the film thickness is 1.5 μm or less, a good press appearance cannot be obtained with a rating of x.

FIG. 6 shows the results of evaluating the same lubrication-plated steel sheet as in FIG. 5 with an L bending press. If there is no press residue, it is [○], and if the punch punch has a slight dot-like press residue, the limit level is allowable, and it is [△]. If plate residue is generated or linear punch residue is generated on the punch. What was done was shown by "x". The pressed residue is generated when the coefficient of dynamic friction is 0.15 or more and the film thickness is 3.0 μm or more, resulting in a defect “x”. Dynamic friction coefficient 0.13 or less,
When the film thickness was 2.75 μm or less, good results “score Δ to ◯” were obtained. From these results, the most desirable film thickness range is 2.5 μm or more for the square cylinder crank press and 2.0 μm or less for the L bending press.

An example applied to a hot-dip galvanized steel sheet is shown below. Chromium-coated hot dip galvanized steel sheet with a coating amount of 15 mg / m ² and an ether ester urethane resin having a molecular weight of 5000 (bisphenol A ether: acid value 1
8, ether / ester ratio 30/70, isocyanate content 8) and propylene glycol epoxy resin (epoxy equivalent 220) with silica sol having an average particle size of 8 nm 21
%, Polyethylene wax having a particle size of 0.6 μm (specific gravity: 0.
93, softening point 120 ° C.) 13% was applied to the coating composition and baked at a plate temperature of 130 ° C. to prepare lubricating steel plates having film thicknesses of 1 μm and 3 μm. The obtained lubricated steel sheet having a film thickness of 1 μm had no pressing residue by an L bending press, and the lubricated steel sheet having a film thickness of 3 μm had good pressability without galling in a square tube press.

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

EFFECTS OF THE INVENTION According to the present invention, high-speed deep-drawing, overhanging, flange forming, and bending workability by a crank press have excellent lubricating properties, and a coating film is less likely to be deteriorated by working and has excellent versatility characteristics. It is possible to provide a non-film-removing lubrication plated steel sheet in which pressing oil can be omitted.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of a coating film of a non-film-removing lubrication plated steel sheet that can omit the press oil of the present invention,

FIG. 2 is a diagram showing types of lubricants and press characteristics,

FIG. 3 is a diagram showing a lubricant concentration and a friction coefficient,

FIG. 4 is a diagram showing the relationship between coating physical properties and silica;

FIG. 5 is a diagram showing a relationship between a square cylinder crank press, a dynamic friction coefficient, and a film thickness,

FIG. 6 is a diagram showing a relationship between an L bending press, a dynamic friction coefficient, and a film thickness.

[Explanation of symbols]

 1 Thin steel plate 2 Plating film 3 Chemical conversion film 4 Lubrication film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C09D 163/00 PKK 8830-4J 175/06 PHP 8620-4J (72) Inventor Kazumi Shibata Chiba Prefecture 1 Kimitsu, Kimitsu-shi Kimitsu Works, Nippon Steel Co., Ltd.

Claims (5)

[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 the layer (a +
b) is 50 to 85% by weight based on the total solids, polyolefin wax (c) is 3 to 30% by weight, and particle size is 3 to 30 n.
Non-film-removing lubrication capable of omitting press oil, characterized in that a coating film having a film thickness of 0.2 to 5 μm obtained by applying and baking an aqueous lubricating paint containing 10 to 40% by weight of silica (d) of m is used. Plated steel sheet. 2. The weight ratio of the polyether skeleton to the polyester skeleton of the ether / ester type urethane resin (a) is 10:90 to 70:30, and the acid value of the urethane resin is 10 to 50. The non-film-removing lubrication plated steel sheet according to claim 1, wherein the press oil can be omitted. 3. The epoxy resin (b) is a type having a glycol skeleton or a bisphenol type skeleton,
The non-film-removing lubrication plated steel sheet capable of omitting press oil according to claim 1, wherein (b) is mixed in a proportion of reacting with 20 to 100% by weight of the carboxyl group of (a). 4. The non-film-removable lubricating plated steel sheet capable of omitting press oil according to claim 1, wherein the polyolefin wax (c) has a melting point of 70 to 160 ° C. and a particle size of 0.1 to 70 μm. 5. The non-film-removal type lubricating plated steel sheet omitting press oil according to claim 1, wherein the polyolefin wax (c) has a saponification value of 30 or less or 0 and has a branched structure. .