JPS63142072A - Coated metal plate - Google Patents

Abstract

PURPOSE:To obtain a coated metal plate having excellent weld stability, workability and corrosion resistance, by coating a metal plate with a coating composition containing an organic synthetic resin vehicle and stainless steel powder having specific shape and diameter at a definite thickness. CONSTITUTION:The objective coated metal plate can be produced by applying a coating composition containing (A) 15-70wt.% stainless steel powder having an average particle diameter of 5-23mu (measured at the shortest diameter of particles) and containing >=50% particles having diameter falling within the above range and (B) 30-85wt.% organic synthetic resin such as epoxy resin as a vehicle to the surface of (C) a metal plate. The coating film thickness is 5-15mu and the average of the shortest diameter of the component A is 1.0-1.5 times the thickness of the coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention particularly relates to a coated metal plate that has excellent welding stability, workability, and corrosion resistance.

[Conventional technology]

For parts of automotive steel plates that undergo processing and welding after being painted, such as fuel tanks, the steel plates are plated if necessary and then an organic film is applied.

When subjected to severe press work or the like in the processing process, deep scratches that reach the steel plate are likely to occur in the plated metal layer, and this area becomes a starting point for corrosion, reducing the size of the part. Therefore, an organic coating is applied on top of it, which provides corrosion resistance and durability.

In the fuel tank, lead-tin alloy plating called turn plating is applied onto a steel plate, and an organic film is applied on top of the lead-tin alloy plating. The dry film thickness is generally about 3 to 50 .mu.r'+1, and this coating serves as an insulator and improves corrosion resistance. However, painted steel plates for such parts go through a processing and welding process.
Since mechanical coatings generally do not have electrical conductivity, a technology that provides this is required.

In Vima Publication No. 61-83032, Pb-S was coated on a steel plate.
It has an n alloy plating layer, has a 3n plating layer as a second layer on it, and has Ni, Zn, AI,
20 to 20% of one or more powders such as Sn and stainless steel are added to the coating film.
A coating containing about 95 V% of melon (=J) imparts electrical conductivity. In JP-A-61-64442, similarly, △1, Ni, C01Cr is coated on a tJb-Sn alloy plating layer.
, one or more types of stainless steel powder, 3% of the non-volatile content of the paint
A highly resistant steel plate for fuel containers coated with a corrosion-resistant paint containing 6% or more of 0 weight E has been disclosed. Tokukai Sho (61-6
In Publication No. 82388, 1 of Ni1CO1S') is placed on a steel plate.
A coating for fuel containers in which a corrosion-resistant paint containing one or more of AI, Ni, stainless steel, CO1Sn, and Cr powder in an amount of 30% by weight or more based on the nonvolatile content of the paint is coated on a seed or two or more metal layers. m steel plate has been released. Special Ivl
No. 61-152/144 discloses a chromate coating on a Zn-Ni alloy plated steel plate, and on top of that, zinc powder containing a chromium-based rust-preventive pigment and having an average particle size of 3 to 20 μm relative to the non-volatile content of the paint. A coated steel plate coated with a zinc-rich paint containing 70 to 80% by weight, with a film thickness of 3 to 10 μm, and an average particle size of Zn powder of 218 based on the film thickness and fiil, etc., has been disclosed.

[Problem that the invention seeks to solve]

In JP-A-61-83032, there is no other description regarding the particle size of metal particles such as stainless steel powder, except that it is 50 μm or less, and according to the examples, the particle size is smaller than the thickness of the resin film. I'm using the one from

Increasing the content of conductive pigments in the coating film improves electrical conductivity and produces good welded bamboo, but the amount of resin decreases, resulting in poor processability. On the other hand, if the suspension is reduced, workability improves, but the conductivity deteriorates and the welded bamboo becomes uneven. Furthermore, the average particle diameter of the conductive pigment has contradictory characteristics depending on its size.

In other words, if the material is small, the conductivity will be better, but during processing, the pigment will easily detach, and that part will easily become defective in the coating.
On the other hand, if it is small, it will cause variations in current conductivity during welding,
Furthermore, it is likely to cause dust to occur during welding, and coating film deterioration is likely to occur. In the case of JP-A-61-83032@, there are problems in that the particle size is smaller than the film thickness, which causes variations in electrical conductivity, tends to cause dust on the welding tip, and deteriorates the coating film. Ta.

F1 No. 61-64/I 112 Publication, JP-A-61
Publication No. 68238 does not mention the particle size of metal particles.

In JP-A-61-152444, the average particle diameter is equal to or twice the film thickness! IN! Contains lead powder to provide weldability. However, the zinc powder exposed on the surface is chemically unstable and tends to give off an oxidized appearance. Then, due to external force abrasion, etc., the protruding parts of the zinc powder are destroyed, resulting in poor workability, and when pressure is applied to the weld 11.7, it is easily destroyed, causing dust and deterioration of the coating film. There were some easy problems.

Conventionally, with hard metals such as stainless steel powder, when particles larger than the film thickness are added to the coating film, the powder face fl becomes 11 during the processing process.
12 Ai L, it was thought that that part would easily cause a coating film defect.

Under these circumstances, the present invention provides Ft! for corrosion-resistant metal plates, especially plated steel plates for automatic mold parts, that do not impair the function of the organic coating, have excellent welding stability, and are excellent in workability. The purpose is to provide a corrosion-resistant liquid i steel plate.

[Means for solving problem jj1] The present inventor, Kasa, selected a stainless steel powder that is chemically stable and difficult to break due to external abrasion, etc., as a conductive bamboo material that does not have corrosion resistance. The present invention was completed as a result of extensive research into the particle size and its distribution that satisfies weldability to Jξ.

In other words, the present invention uses stainless steel powder having an average particle size measured by the shortest particle diameter in the range of 5 to 23 μm, and in which 50% or more of the particle size is within the range.
5-70% by weight, 30-30% organic synthetic resin as vehicle
A coating composition containing 85% by weight is coated on a metal plate with a film thickness of 5 to 1
The shortest length of the 11 stainless steel powders (
It is a painted metal plate that is coated so that the average value of the coating film is 1.0 to 1.5 (R).The synthetic resins used are acrylic, polyester, and alkyd. , ebexi type, phenol type, polyurethane type, fluorine type, silicone type, etc. are used.

The metal plate may be a single metal plate such as a steel plate, or it may be plated with -Pb+Sn, Sn, Zn, Cr, Zn+Ni, etc., or alloy plated, and coated with paint adhesion such as a chromate film. The term metal plate includes those that have been treated to improve the quality. In this way, IFJ
Protruding particles on the surface ensure sufficient electrical conductivity during welding.
Moreover, since it uses stainless steel powder as the metal, it is chemically stable and is not easily destroyed by external force abrasion, so there is no problem of paint film deterioration due to welding tip peeling or dust generation.

If the particle size is less than the same as the coating thickness, the electrical conductivity will vary, and if it is 1.5 times or more, the pigment is likely to be detached during processing. Moreover, by adopting this particle size, excellent weldability can be exhibited with a smaller content than the conventionally used conductive WW pigment. Is this the welding used when welding? The probability of contact between the conductive pigments protruding on the li-polar film becomes ), or when the coating films are overlapped, the probability of contact between the conductive pigments and the conductive pigments increases. This is considered to be the reason. Figure 1 shows stainless steel (S)
The balance relationship is shown for various cases of the content ω in the coating film of US) and the particle size/film thickness ratio, with the vertical axis representing weldability and the horizontal axis representing workability. Regarding the particle size distribution of each particle size of stainless steel powder, it is preferable to have a distribution within a narrow range (for example, the average '#I diameter is 70% or more), but it is necessary to repeat the particle classification 3 to 4 times. Otherwise, it is not suitable for performance and increases costs. If it has a particle size distribution of 50% or more in the vicinity of the average 1H1, it is excellent in terms of weldability and workability.

The average particle diameter measured using the shortest diameter of the JJ powder particles was used because the particles were sieved during wintering [1]. This is because it is determined by. In addition, the reason for specifying that 50% or more of the particle size distribution is within the range is that the particle size distribution may not necessarily be a normal distribution, and even if the average particle size is within the range, This regulates cases where mountains are out of range.

(Example) (1) Preparation of paint 1 Based on boxy resin, average particle diameter is 4μm, 8μm
Paints were prepared using stainless steel powders of m, 10 μm, 13 μm, and 20 μm, respectively. At that time, the stainless steel powder content in 10 μm of dry coating film was 10.20.
Various paints were prepared to have a concentration of 40.65.75fflff1%.

(2) Preparation of test pieces Each of the paints prepared above was coated on a Pb-3n alloy plated steel plate with a thickness of 0.8 mm using a J-uni bar coater to give a dry film thickness of 10 μm. 60 at 220℃ in baking furnace
The specimen was cured for a few seconds and used as a test piece.

(3) Test method The above samples were tested for weldability, workability, and
Corrosion resistance was evaluated.

(a) Weldability: M1 with spot welding machine and seam welding machine
■ Spot welding machine welding conditions Electrode: Ri1com-copper 4.5mφ Welding union I! : Apply lacquer to the inside.

Pressurized Crab 2007 (g Current application time: 10 cycles ■ Seam welding 1g machine welding part f1 ``Top electrode nichrome-copper 4. O# width trapezoidal electrode welding combination: J the inside of the coating film.

Pressurized crab 400 kg Speed: 2.5 m/sin Current application time: Continuous Evaluation 1lIIi As criteria, evaluation 11ii was performed on the welding current range, the state of generation of plugs, and the appearance of the welded part (dust generation, etc.).

(B) Workability Two-cylinder molded shape: 80g + φ Flat 2 cylinder clearance: 1m Blank → Noise: 1zlOs + φ Wrinkle press crab 4 to 9/ad Molded height: 40jIIl The evaluation criteria are the appearance of the processed part and the coating film by 1M Hirohan Dave A peel test was evaluated.

(c) ii 4 Corrosion resistance: Methanol mixed gasoline resistance, salt water spray resistance ■ Methanol mixed gasoline molded into a cylinder with upper striations b
However, the test was carried out for 1 month at 40°C with a depth of 120 m.

Composition (volume ratio) Methanol 15.00% Gasoline 84.75% Water 0.25% Total 100. 00% ■Salt spray resistance test Spray 5% saline at 35℃ for 240 hours I conducted a test. The above results are shown in Table 1.

In Table 1, test M\"J1 to 6 are examples of the present invention, test amounts) -37 to 9 are test numbers 10 to
12 has an average particle diameter/coating film thickness ratio smaller than that of the present invention J, test Wt 13 to 15 are stainless steel powders), and the average particle diameter/coating thickness ratio is smaller than that of the present invention. A comparative example in which the diameter is smaller than that of the present invention is shown. Trial ki number 16~
20 is a case where the content 11 of stainless steel powder in the coating film is less than that of the present invention, and 16 is a case where the particle size is small and the particle size /
When the coating film thickness ratio is small, 17 is when only the particle diameter/coating film thickness ratio is small, 18.19 is when only the content ti+ of the stainless steel powder in the coating film is less than the present invention, and 20 has less stars. , and each comparative example shows a case where the particle diameter/coating film thickness ratio is large. Test numbers 21 to 25 of Comparative Example (■) contain no stainless powder in the coating film! This is the case where ji is larger than the present invention, and in 21 of them, particle i\ is small, and particle 1\/
When the coating thickness ratio is small, 22 is when the particle diameter / coating thickness ratio is small, 23.24 is when only the content is large, and 25 is when the particle diameter is large and the particle diameter / coating thickness ratio is higher than the present invention. Comparative examples for large cases are shown. Comparative Example ■ has poor weldability, and Comparative Example ■ has poor workability.

〔Effect of the invention〕

According to the present invention, it is possible to provide a coated metal plate that has stable weldability with no variation in weldability, and has excellent workability and good resistance.

[Brief explanation of the drawing]

Figure 1 shows the content m in the coating film of stainless steel powder and the particle size/
ilJ? FIG. 4 is a diagram showing the balance relationship for various cases of ratios, with the vertical axis representing the quality of weldability and the horizontal axis representing the quality of workability.

Claims (1)

[Claims] 15 to 70% by weight of stainless steel powder with an average particle diameter measured by the shortest particle diameter in the range of 5 to 23 μm and 50% or more of the particle size distribution falling within this range, and 30 to 70% by weight of an organic synthetic resin as a vehicle. A coating composition containing 85% by weight is applied to a metal plate so that the coating film thickness is 5 to 15 μm, and the average value of the shortest diameter of the stainless steel powder is 1.5 μm of the coating thickness.
A coated metal plate that is painted to be 0 to 1.5 times larger.