JPH1052881A - Resin coated metal plate with mold drag resistance and corrosion resistance and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve and stabilize processability, corrosion resistance after processing and coating film adhesive properties by fixing a solid lubricant to a resin film of a resin coated metal plate and specifying height and areal ratio of the lubricant. SOLUTION: A solid lubricant 3 such as polyolefin wax or a fluororesin is mixed with a resin coating liquid of an epoxy, urethane or acrylic, and a ground metal plate 1 of a zinc-plated steel plate or aluminum-plated steel plate is coated with the resultant mixture. After coating, it is dried at a temperature of a softening point or higher of the lubricant, and hence the lubricant 3 is projected from a surface of a resin film 2 and fixed. A protruding height of the lubricant 3 from the surface of the film 2 is 0.01 to 1.5μm, and an areal ratio of the lubricant 3 as planely seen is 1 to less than 15%. Thus, processability (including black modification) is improved, and corrosion resistance after processing is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated metal plate used as a material for automobiles, household electric appliances, building materials and the like, and a method for producing the same. A resin-coated metal plate capable of exerting excellent effects on both mold resistance and corrosion resistance by fixing a lubricant and satisfying a predetermined requirement for a fixed form of the solid lubricant. A useful method for producing such a resin-coated metal sheet.

[0002]

2. Description of the Related Art Generally, surface treated steel sheets such as organic resin coated steel sheets are widely used as materials for automobiles, household electric appliances, building materials and the like. In most cases, this surface-treated steel sheet is used after being subjected to processing such as bending and press forming. Conventionally, press oil is applied and processed, followed by degreasing, and further, if necessary, phosphate. It has been pre-treated such as treatment and painted for use.

[0003] In recent years, however, the press oil application and degreasing steps have been omitted on the user side, thereby preventing the generation of chlorofluorocarbons and the generation of alkaline waste liquid during the scattering and degreasing of press oil, and the pretreatment. There is a need for pollution-free and labor-saving processes that enable painting without coating. Therefore, from the viewpoint of coping with such a situation, an organic resin-coated steel sheet that can be processed without press oil and that can be coated without performing a pretreatment such as a phosphate treatment has been developed.

[0004] In order to enable processing without press oil, a lubricant such as a solid lubricant is mixed into a resin film so as to ensure lubricity required during press processing of an organic resin-coated steel sheet. ing. In addition, from the viewpoint of reducing the friction coefficient of the surface and realizing better workability, a spherical wax resin having an average particle diameter larger than the resin coating film thickness is used as a solid lubricant, and this is used as a solid lubricant in the resin film. In some cases, the solid lubricant is protruded from the surface of the resin film by the addition of the compound to form irregularities on the surface.

As such a technique, for example, Japanese Patent Publication No. 5-86
No. 916, a polyolefin wax having a resin adhesion amount of 0.3 to 3 g / m ² and an average particle diameter of 1 to 7 μm larger than the dry film thickness of the resin was added to the resin film.
A lubricated resin-treated steel sheet containing 20 parts by weight or less with respect to 00 parts by weight is disclosed.

In Japanese Patent Publication No. 6-59455, the coating amount is 0.2 to 4.0 g / m ² , the melting point of the coating is 120 ° C. or more, and the primary dispersion particle diameter is 20 μm.
Particle size containing 10% by weight or more of
0 μm of solid lubricant was added to 0.02
A lubricating thin-film resin steel sheet containing up to 0.4 parts by weight has been proposed.

[0007]

In the prior art, the adoption of the above-mentioned structure has provided a certain effect as far as lubricity is concerned. However, these techniques have the following problems.

[0008] That is, during continuous processing or transportation, the solid lubricant present in the coating or protruding from the coating is desorbed or eluted by sliding with a heated mold or press machine. There's a problem. When such a situation occurs, recesses and defects are formed in the film, so that the corrosion resistance of the product is significantly reduced, and the detached particles accumulate in the mold and adhere again to the product, turning the product black and the commercial value (Hereinafter, such a phenomenon is referred to as “blackening”). Also, the protrusion height of the solid lubricant and the occupied area ratio of the protrusion on the surface vary, and the metal layer is scratched by sliding with the mold, especially during bending or overhanging when molding a video or cassette chassis. There are problems that the galling resistance is deteriorated and the performance such as adhesion of the coating film is not stable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin-coated metal sheet which can be bent and stretched well without press oil and has good corrosion resistance of a product after the processing. And a useful method for producing such a resin-coated metal sheet.

[0010]

Means for Solving the Problems The resin-coated metal plate of the present invention which can solve the above-mentioned problems is that a surface of a base metal plate is coated with a resin film and a solid lubricant is coated on the film. The solid lubricant has a protrusion height from the resin film surface of 0.01 to 1.5 μm, and the solid lubricant has an area ratio of 1 to 15 in plan view.
%.

In the resin-coated metal sheet of the present invention, the solid lubricant having a major axis D ₁ of 0.1 μm or more is N _A
Included number, when the number of the solid lubricant which satisfies these following formula (1) was N _B, these N _A and N _B
Satisfies the relationship of the following formula (2) and the following (1) on an arbitrary line having a length of 200 μm on the surface of the resin film.
When the number of solid lubricants satisfying the formula is 1 to 100, the effect of the present invention is maximized. _{0.1μm ≦ D 1 ≦ 50μm ... (} 1) 0.90 ≦ (N B / N A) ≦ 1.0 ... (2)

In producing the resin-coated metal plate of the present invention, a resin coating solution containing a solid lubricant is applied to the surface of the base metal plate and then dried at a temperature equal to or higher than the softening point of the solid lubricant. The solid lubricant may be fixed to the surface of the resin film so that the protrusion height and area ratio of the solid lubricant satisfy the above ranges.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is constituted as described above. In short, a solid lubricant is fixed on the surface of a resin film, and the height and area ratio of the solid lubricant (area ratio in plan view) ) Was properly adjusted, and the above-mentioned object was splendidly achieved, and the present invention was completed. Regarding the reason why the above-mentioned effects were obtained by the present invention,
Although we could not clarify all of them, we could think as follows.

FIG. 1 is a diagram schematically showing a surface portion of a resin-coated metal plate of the present invention. In the drawing, 1 indicates a base metal plate, 2 indicates a resin film, and 3 indicates a solid lubricant. That is, as shown in FIG. 1, in the resin-coated metal plate of the present invention, since the solid lubricant 3 is present in a protruding state on the surface of the resin film, the solid lubricant 3 is formed between the resin film and the mold during continuous pressing. It is thought to act as a lubricant between them to improve workability (including blackening resistance in addition to mold galling resistance). In addition, this solid lubricant suppresses galling and the like due to impact and sliding between the resin-coated metal plate and the mold, so that the appearance of the product becomes beautiful and the resin film remains sound. It is considered that the corrosion resistance of the molded article (hereinafter referred to as “corrosion resistance after processing”) is also improved.

With respect to such a resin-coated metal plate of the present invention,
In a conventional resin-coated steel sheet, as shown in FIG.
Since the solid lubricant 3 having a particle size larger than the thickness of the film exists therein, the solid lubricant 3 is detached by sliding with a mold during continuous processing, and countless concave portions are formed in the film. And
It is considered that the corrosion resistance is lowered after processing, and the desorbed material is reattached to the mold to cause the blackening described above. Alternatively, even if the particle size of the solid lubricant is smaller than the film thickness, the solid lubricant dissolves or blows out due to sliding with a heated mold during continuous processing to generate a number of fine defects in the film. Therefore, it is considered that the corrosion resistance after processing is lowered.

Further, according to the present invention, a coated film (coating film)
Is also stabilized at the same time. In general, when a lubricant is present on the surface of a film, the adhesion of the film tends to decrease.In particular, when used in an environment where water adheres after painting or is immersed in water, water starts from the lubricant. It penetrates and deteriorates coating film adhesion. However, as in the present invention, by appropriately controlling the coverage, height, distribution state, and the like of the lubricant on the resin film surface, not only the coating adhesion (primary coating adhesion) during normal use, but also boiling. They succeeded in stabilizing even the coating adhesion (coating secondary adhesion) after immersion in water.

Hereinafter, each requirement specified in the present invention will be described. In the present invention, as shown in FIG. 1, the solid lubricant 3 is projected and fixed to the surface of the resin film 2 and, for example, the solid lubricant observed by a scanning electron microscope (SEM) is applied to the surface of the resin film 2. Projecting height from 0.01 to
The workability (including blackening) is improved by satisfying the requirements of 1.5 μm, the area ratio occupied by the solid lubricant in plan view of 1 to less than 15%, and the like. And the corrosion resistance after processing is dramatically improved.

In the present invention, the protrusion height of the solid lubricant must be 0.01 μm or more. When the protrusion height is less than 0.01 μm, the lubricating effect on the surface is not sufficient, and the mold is seized at the time of processing, and the corrosion resistance of the portion is reduced. On the other hand, when the protrusion height of the solid lubricant is 1.5
If it exceeds μm, the lubricant will be scraped off due to sliding with the mold during processing, and the blackening resistance will be rather deteriorated. Sex becomes unstable. A more preferable range of the protrusion height of the solid lubricant has a lower limit of 0.02 μm and an upper limit of 1.0 μm.

The area ratio occupied by the solid lubricant in plan view must be 1 to less than 15%. This area ratio is 1
%, The effect of improving workability such as lubricity and mold galling resistance at the time of processing is not sufficient, and when it is 15% or more, the secondary adhesion of the coating film after coating is reduced. The preferred lower limit of the area ratio is 2%, and the preferred upper limit is 12%. By setting the area ratio in such a range, the effects of the present invention are maximized.

Incidentally, the SEM observation in the present invention shows that the resin-coated metal
1 mg / m of gold (Au) on the surface of the plate ^Two ~ 1g / m^Two Evaporation
After that, the scanning microscope “S-2700” [trade name:
Using Hitachi, Ltd.] at an accelerating voltage of 15 kV.
EM observation.

On the other hand, the major axis D ₁ of the solid lubricant is 0.1 μm.
m or more. The major axis D ₁ is 0.1μ
If it is less than m, lubricity and mold galling resistance will be reduced, and the effect of improving workability will not be recognized, and the corrosion resistance of the mold galling portion will be reduced. It should be noted that the major axis D ₁ is 0.
More preferably, it is 3 μm or more.

[0022] When the long diameter D ₁ is the number of individuals lubricant is 0.1μm and N _A, the number of individuals lubricant The diameter D ₁ is and 50μm or less at 0.1μm was N _B, the the number ratio of (N _B / N _a) is 0.90 or more 1.
The value is preferably 0 or less [formula (2)], and more preferably 0.95 or more. The above ratio is 0.9
When it is less than 0, the contact area between the coating film and the resin film decreases, and in some cases, a gap is generated, and the secondary adhesion of the coating film becomes unstable.

Further, a length of 200 on the surface of the resin film
It is preferable that the number of solid lubricants satisfying the expression (1) on an arbitrary line of μm is 1 to 100. If the number is less than 1, the effect of improving galling resistance and post-processing corrosion resistance is not sufficient, and if the number exceeds 100,
The contact area ratio between the coating film and the solid lubricant increases, and in some cases, a gap is formed between the coating film and the secondary adhesion of the coating film. The preferred lower limit of this number is three, and the preferred upper limit is eighty.

Next, the manufacturing method of the present invention will be described. According to the method of the present invention, the solid lubricant is fixed to the surface of the resin film by applying a resin coating solution containing the solid lubricant and then drying the applied liquid at a temperature equal to or higher than the softening point of the solid lubricant. At this time, the lubricant that has flowed by drying the solid lubricant at a temperature equal to or higher than the softening point causes a difference in specific gravity and a difference in surface free energy between the solid lubricant and air, and between the resin liquid (or resin film) and air. The resin film is concentrated on the surface of the resin film due to a difference or the like, and after the drying, the solid lubricant is fixed on the surface of the resin film as shown in FIG.

The type of the solid lubricant used in the present invention is not particularly limited, but typical examples thereof include polyolefin wax-based solid lubricants such as polyethylene and polyolefin, and fluororesins such as tetrafluoroethylene. Solid lubricants, carnauba wax and the like. Among them, it is most preferable to use a polyolefin wax-based solid lubricant. Specific examples of such solid lubricants include, for example, DIJET E-17 (trade name: manufactured by Ryo Kagaku Co., Ltd.), KUE-1, KUE-5, and KUE-8.
[All brand names: manufactured by Sanyo Chemical Industry Co., Ltd.], Chemipearl W-100, W-200, W-300, W-400,
W-500, W-640, W-700 (all trade names: manufactured by Mitsui Petrochemical Industries, Ltd.), Elepon E-20
[Product name: Nika Chemical Co., Ltd.], Dispalon SE21
0-15T, SE1020-7TN, SE478-
10T, SE470-10T, SE-480-10
T, SR510-10X, SE470-10X, SE
1020-7X [All trade names: manufactured by Kusumoto Kasei Co., Ltd.]
And other commercially available products can be used.

Next, the present invention relates to the resin-coated metal plate of the present invention.
A base metal plate (and a plating method), a chemical conversion treatment method, a resin film, a coating method, and the like will be described. However, the present invention is not limited thereto, and any material that satisfies the requirements of the present invention can be used.

First, the base metal sheet (base sheet to be treated) used in the present invention includes cold-pressed steel sheets, galvanized steel sheets, aluminum-plated steel sheets, Zn-Al alloy-plated steel sheets, Zn-Ni alloy-plated steel sheets, stainless steel sheets, aluminum sheets and the like. Can be mentioned. Examples of the plating method include an electroplating method, a hot-dip plating method, and a vapor deposition plating method.

In a resin-coated steel sheet, a chemical conversion treatment is generally performed between an original plate (the above-described base metal plate) and a resin film. Examples of the chemical conversion treatment include a phosphate treatment and a chromate treatment. The chromate treatment method may be any of a reaction type, a coating type and an electrolytic type.

Examples of the resin used for the resin film include epoxy resins, urethane resins, acrylic resins, polyester resins, polyethylene resins, and melamine resins. It is recommended that a solid lubricant be added. Further, these resins may be mixed with a melamine-based, epoxy-based, isocyanate-based, aziridine-based, or carbodiimide-based cross-linking agent to cross-link the resins. Furthermore, in the resin coating solution,
Workability in the resin-coated metal plate of the present invention, corrosion resistance, as long as the coating adhesion is not impaired, other than the above resin, solid lubricant and crosslinking agent, colloidal compound, pigment, diluting solvent, surfactant, defoaming agent, Various additives such as a penetrant, a film thickener, a thickener, and a bone agent may be added.

The resin-coated metal plate of the present invention can be produced by applying the above-mentioned resin coating solution to the surface of the base metal plate by an arbitrary method and drying it. Is not limited at all, for example, by applying a roll coater method, a spray method, a curtain flow coater method or the like to the surface of a zinc-based plated steel sheet whose surface has been cleaned or subjected to chromate treatment. Can be. Of these, the roll coater method is most practically preferable in consideration of processing for uniformity of film thickness, processing cost, and coating efficiency. The resin-coated metal plate of the present invention includes a metal plate having a resin film formed on only one side or both sides.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples do not limit the present invention, and any design changes in the spirit of the present invention will be described. It is included in the range.

[0032]

EXAMPLES Various test materials were prepared by the following procedure. First, an electrogalvanized steel sheet (thickness: 0.8 m) was used as an original sheet on which the resin film forming composition (resin coating liquid) was applied.
m, a plating amount: 20 g / m ² ) and subjected to a chromate treatment (Cr adhesion amount: 20 mg / m ² ). On the other hand, as the resin coating solution, a urethane resin having a shear D hardness of 51 [“Superflex” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] was added to spherical polyethylene wax particles (softening point:
110 to 140 ° C.) and colloidal silica [“Snowtex O” manufactured by Nissan Chemical Industries, Ltd.] were used.

The above resin coating solution is applied to an original plate and
After squeezing with a tool, the plate temperature reaches 80-180 ° C
Baking under the conditions, the amount of resin film attached is 0.5-2.0g
/ M ^Two The test material was manufactured as follows. At this time, the resin film
The amount of adhesion of the
So adjusted. The form of the solid lubricant shown in Table 1 below
(The ratio of the height of the solid lubricant, the coverage, and the numerical value of the solid lubricant N
_B / N_A , Solid lubricant separated by 200μm line segment
Number), the particle size of the wax to be added,
Control by changing the amount and baking temperature
Was. For the obtained resin-coated metal plate, the following items
The performance was evaluated. The results are summarized in Table 1 below.
Shown. The evaluation method for each item of performance is as follows.
You.

[Evaluation of Performance] Surface Observation Gold (Au) was applied on the surface of the test material in an amount of 1 mg / m ² to 1 g / m.
^{2 After} vapor deposition, using a scanning microscope "S-2700" (trade name: manufactured by Hitachi, Ltd.), acceleration voltage: 15 kV
Was observed by SEM. Measurement of Dynamic Friction Coefficient Sliding was performed at a pressing force of 150 kg using a sliding test apparatus, and the dynamic friction coefficient was determined from the tensile load.

Evaluation of mold galling resistance and blackening resistance A U-bending test was performed using a single press machine, and the galling state and blackening of the sliding surface after the test were evaluated. The evaluation criteria are as follows. (Evaluation criteria for mold galling resistance) A: No galling or flaws are observed. ：: Galling and flaws are hardly recognized. Δ: Slight galling and flaws are observed. ×: Clear galling and flaws are observed. (Evaluation criteria for blackening resistance) A: No blackening was observed. ：: Almost no blackening was observed. Δ: Some blackening is observed. ×: Clear blackening is observed.

Evaluation of corrosion resistance after processing After using a single-shot press tester, the test material was U-bent,
The molded product was subjected to a salt spray test according to the method described in JIS Z2371 to investigate the corrosion resistance after processing. The measurement results show the time of 1% white rust generation on the sliding surface.

Evaluation of Coating Adhesion A melamine alkyd-based coating “Amirac 1000” (trade name, manufactured by Kansai Paint Co., Ltd.) was applied and the coating was applied at 130 ° C. for 2 hours.
Baking for 0 minutes, the coating thickness: 20 μm. Subsequently,
The primary adhesion and the secondary adhesion of the coating film were evaluated by the following methods (a) and (b). The evaluation criteria are as follows for both primary and secondary. (Evaluation criteria for coating film adhesion) A: No peeling of the coating film was observed. ：: Some peeling of the coating film was observed. Δ: Clear peeling of the coating film is observed. ×: Peeling of the coating film was observed before the tape was peeled. (A) Primary adhesion of coating film: Using a cutter knife, 100 squares of 1 mm ² were drawn on the painted surface and extruded by 6 mm with an Erichsen tester to perform a tape peeling test. (B) Secondary adhesion of the coating film: A boiling water test (immersion in boiling water for one hour) was carried out, left for 1 hour, and evaluated in the same manner as the primary adhesion.

[0038]

[Table 1]

From these results, the following can be considered.
First, the test material No. 1 to 12 are examples satisfying the requirements defined in the present invention, and good results are obtained in any of workability (mold seizure resistance and blackening resistance), corrosion resistance after molding, and coating film adhesion. You can see that it is done. On the other hand, the test material No. 13 to 21 are comparative examples lacking any of the requirements specified in the present invention, and are inferior in any of the performances as shown below.

(1) Test material No. In No. 13, the protrusion height of the solid lubricant is less than the lower limit specified in the present invention, and the workability and the post-workability corrosion resistance are reduced. (2) Test material No. In the case of No. 14, the protrusion height of the solid lubricant exceeds the upper limit specified in the present invention, and the black change resistance among the workability is reduced. (3) Specimen No. having an area ratio of the solid lubricant less than the lower limit specified in the present invention. In the case of No. 15, the workability and the post-process corrosion resistance are reduced. (4) Specimen N whose area ratio exceeds the upper limit specified in the present invention
o. In the cases of Nos. 16 and 17, the adhesion of the coating film was reduced. (5) Test material No. 18 is the long diameter D of the solid lubricant
₁ is less than the lower limit specified in the present invention, and the workability and the corrosion resistance after working are deteriorated. (6) Test material No. In No. 19, the ratio N _B / N _A was less than the lower limit specified in the present invention, and the coating film adhesion was deteriorated. (7) Specimen No. No. in which the number of solid lubricants contained on the surface and divided by 200 μm line segments is less than the lower limit specified in the present invention. In the case of No. 20, the processability and the post-process corrosion resistance are reduced. (8) The sample material No. whose number of solid lubricants separated by a line of 200 μm contained on the surface exceeds the upper limit specified in the present invention. In the case of No. 21, the adhesion of the coating film was reduced. (9) Specimen No. 1 which was dried below the softening point of the solid lubricant to form a resin film. In the case of No. 22, the blackening resistance, corrosion resistance after processing, and coating film adhesion are reduced.

[0041]

The resin-coated metal sheet of the present invention has a solid lubricant fixed on a resin film, and the height and area ratio of the solid lubricant are appropriately controlled, so that the diameter and constant line segment can be adjusted as necessary. By appropriately controlling the number of pieces to be separated by the process, a resin-coated metal plate having improved or stabilized workability (mold seizure resistance and blackening resistance), corrosion resistance after processing, coating film adhesion, and the like was realized. . As a result, the oiling and degreasing work during molding and the pretreatment for painting (phosphate treatment) can be omitted, and the working environment can be improved, and the productivity and cost can be reduced by saving steps. can get. Further, the resin-coated metal sheet of the present invention is excellent in corrosion resistance after molding, so that it can be used in a wide range of applications, for example, a product can be used without painting.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a state of a solid lubricant present in a resin-coated metal plate of the present invention.

FIG. 2 is a schematic diagram showing a state of a solid lubricant present in a conventional resin-coated metal plate.

[Explanation of symbols]

 1 Base metal plate 2 Resin film 3 Solid lubricant

Claims (3)

[Claims] 1. A resin film is coated on a surface of a base metal plate, and a solid lubricant is fixed on the film. The solid lubricant has a protrusion height from the resin film surface of 0.1 mm. A resin-coated metal sheet excellent in mold galling resistance and corrosion resistance, characterized in that the solid lubricant has an area ratio of from 1 to 1.5 μm and an area ratio of the solid lubricant in plan view of less than 1 to 15%. Wherein is a solid lubricant diameter D ₁ is 0.1μm or more is included N _A number, when the number of the solid lubricant which satisfies these following formula (1) was N _B, these N _A
And N _B satisfies the following relationship (2), and the number of the solid lubricant that satisfies the following formula (1) in an arbitrary line length 200μm on the resin film surface 1-100
The resin-coated metal sheet according to claim 1, wherein _{0.1μm ≦ D 1 ≦ 50μm ... (} 1) 0.90 ≦ (N B / N A) ≦ 1.0 ... (2) 3. A resin coating solution containing a solid lubricant is applied to the surface of the base metal plate, and then dried at a temperature equal to or higher than the softening point of the solid lubricant, so that the solid lubricant is applied to the surface of the resin film. A method for producing a resin-coated metal plate having excellent mold galling resistance and corrosion resistance, comprising fixing the resin-coated metal plate according to claim 1.