JPS62289274A - Rust prevented steel sheet having excellent workability - Google Patents

Abstract

PURPOSE:To provide the titled steel sheet having excellent film adhesiveness in the working stage by providing a film layer essentially consisting of a composite or mixed material composed of an urethane resin and silicon dioxide on a zinc plating layer provided on the steel sheet. CONSTITUTION:The film layer essentially consisting of the composite or mixed material composed of the urethane resin and silicon dioxide is provided on the zinc plating layer provided on the steel sheet. The above-mentioned urethane resin refers to the reaction product of an org. polyisocyanate (e.g., tolylenediisocyanate) and polyhydric hydroxy compd. (e.g., polyalkylene glycol) and polyvalent amino compd. (e.g., methylene orthochloroaniline). The rust prevented steel sheet obtd. in such a manner has excellent film adhesiveness in the working stage.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a rust-proof steel plate with excellent workability, and more specifically, to a rust-proof steel plate for use in automobile bodies, household appliances, and buildings. This invention relates to a rust-proof steel plate with excellent workability for use in walls, etc.

``Rainbow Toku R'' Various configurations have been proposed and used as rust-proof steel sheets.For example, when used for automobile bodies, rust-proof steel sheets commonly known as synchro metal are used. is used, but this is the first material containing chromium compounds on the steel plate.
The steel sheet consists of a second layer of non-frich paint containing zinc powder and resin (hereinafter referred to as zinc-rich anti-corrosion steel sheet), and has good corrosion resistance and is coated with electro-deposition and a second layer of non-fitch paint containing zinc powder and resin. Be able to do spot welding.

However, this zinc-rich rustproofing plate has problems as described below.

(1) In order to ensure corrosion resistance and electrodeposition coating properties, the above-mentioned second
Since the layer contains 80 wt % or more of zinc powder, the film peels off in powder form during press working, etc., causing processing scratches.

(2) If the zinc-rich film is applied thickly, for example 10 μm or more, large amounts of zinc powder and resin will be present, and the electrode tip will be contaminated by the combustion residue of zinc and resin from continuous spot welding. Dressing frequency increases, leading to deterioration of workability.

However, regarding a rust-proof steel plate that takes into consideration the above-mentioned problems of the zinc-rich rust-proof steel plate, Japanese Patent Application Laid-Open No. 58-0981
No. 72 and Japanese Unexamined Patent Publication No. 108292/1987 propose rust-preventing steel sheets with an organic composite silicate film of about 1 μm. MO in the film that is the main component
It is essential to contain oxyacid or alkoxide chelate compounds of lW, ■, Sn, and B5Si, and does not contain urethane-based RF machine composite silicate.

In addition, such rust-proof steel sheets do not have sufficient film adhesion under severe processing conditions, such as drawbead tests and various adhesion tests after painting, such as two coats of electrodeposition and intermediate coating. There is a problem.

[Invention') <Problems to be solved] The present invention was made in view of the various problems in conventional rust-proof steel plates as explained above, and as a result of intensive research by the present inventor, We have developed a rust-proof steel sheet with excellent film adhesion and excellent workability.

[Means for solving the problems] The p-proof film with excellent workability according to the present invention! Steel plate is (1)! i
A rust-proof steel sheet with excellent workability, which is characterized by having a coating layer mainly composed of a composite material or a mixture of urethane resin and silicon dioxide on the zinc-based plating layer provided on the sheet. As the first invention, (2) jI! A film layer whose main component is a composite material or mixed material of urethane resin and silicon dioxide containing zinc powder is provided on the zinc plating layer provided on the i-board. This invention consists of two inventions, with the second invention being a rust-proof steel plate with excellent workability.

Note that, if necessary, a chromate layer may be formed between the zinc-based plating layer and the coating layer whose main component is a composite material or mixed material of urethane resin and silicon dioxide.

In addition, various anti-corrosion pigments can be coexisted in the coating layer to further improve corrosion resistance, and Zn powder can be added to impart conductivity to the coating layer and improve corrosion resistance. can be done.

Examples of the steel sheet provided with a zinc-based plating layer used in the rust-proof steel sheet with excellent workability according to the present invention include a single-layer zinc-plated steel sheet, a zinc alloy-plated steel sheet, and a multilayer-plated steel sheet thereof.

The film layer contains urethane resin or urethane resin and resin such as evokin, acrylic, etc. as resin components.
It is also possible to prepare a mixture with various resins such as phenol.

This urethane resin and silicon dioxide may be made into a composite material using a silicon coupling agent, or may be made into a mixed material.

The bouletane resin referred to herein is a reaction product of an organic polycarbonate, a polyvalent hydroxy compound, and a polyvalent amine compound.

T child unit polyisonoanate includes tolylene diisocyanate, nophenylmethane diisonanate, polymethylene polyphenylisocyanate,
Aliphatic, aromatic, ring group isocyanates such as hexamethylene diisonanate, quinlylene diisocyanate, naphthalene diisocyanate, toridine diisocyanate, isophorone diisocyanate, hydrogenated quinlylene diisocyanate, hydrogenated dicyclohexylmethane diisocyanate, and their trimerization and trimerization products There is.

Examples of polyhydric hydroxy compounds include polyalkylene glycols, polyamine polyols, polymer polyols, polyether polyols such as polytetramethylene glycol, adipate polyols,
Examples include polyester polyols such as phthalic acid polyols, polycaprolactone polyols, and polycarbonate polyols, and polyhydric alcohol compounds such as trimethylolpropane and butanediol.

Examples of polyvalent amino compounds include methylene orthochloroaniline, diaminodiphenylmethane, ethylenenoamine, diethylenetriamine, hydrazine, isophoronediamine, and triethylenetetramine.

Polyurethane resins can be broadly categorized based on processing methods: (1) Urethane prepolymers are synthesized through polymerization reactions of various organic polyisocyanates and polyvalent hydroxy compounds, and during processing, polyurethane prepolymers are synthesized using polyvalent amino compounds, polyvalent hydroxy compounds, moisture, etc. A thermosetting (room temperature curing) polyurethane resin that turns into a resin.

(2) One-piece polyurethane resin that converts various organic polyisocyanates, polyvalent hydroxy compounds, polyvalent amino compounds, etc. into a mixed resin during processing.

(3) Urethane prepolymer or
Solvent volatilization type (including some moisture curing type) polyurethane resins made by dissolving and diluting polyurethane resins in various solvents.

(4) Thermoplastic polyurethane resin that is obtained by thermally melting polyurethane resin obtained by polymerization reaction of various organic polyisocyanates and polyhydric hydroxy compounds during processing.

(5) Various organic polyisocyanates, polyurethane resins obtained by introducing hydrophilic groups during the polymerization reaction of polyhydric hydroxy compounds, or urethane prepolymers are emulsified in water, or various organic polyisocyanates,
A hydrogenated polyurethane resin obtained by forcibly emulsifying a polyurethane resin obtained by the polymerization reaction of a polyhydric hydroxy compound or a urethane prepolymer using a surfactant or colloid agent.

etc.

[Example] An example of rust prevention with excellent workability according to the present invention will be described.

Example 1 Polytetramethylene ether glycol dehydrated under reduced pressure (
After adding 101 parts of methyl ethyl ketone to 202 parts of OH, V, 55J) and mixing uniformly, 2°4- and 2,
6 tolylene diisocyanate 80:20 mixture 34.
Add 8 parts and react at a temperature of 80°C for 2 hours to obtain 2.4
A urethane prepolymer solution containing 8% isocyanate groups was obtained.

In a separate reactor, 600 parts of methyl ethyl ketone and 10.7
300% of the above urethane prepolymer solution is added to this solution and mixed uniformly.
10 parts dropwise at a temperature of 10 to 20°C, then 5 parts
A polyurethaneurea polyamine solution was obtained by reacting at a temperature of 0° C. for 30 minutes.

Next, 25.8 parts of trimet acid anhydride was added to this solution, and after uniformly dissolving it, the temperature was raised to 50°C and the temperature was increased to 30°C.
Allowed to react for minutes.

Subsequently, an aqueous solution of 1,008 parts of sodium hydroxide dissolved in 650 parts of water was added, methyl ethyl ketone was distilled off under reduced pressure, and water was added to adjust the resin content to obtain an emulsion with a concentration of 30%.

This water-soluble urethane emulsion (30% solids)
: 100 parts by weight Coroiglue strength (Sing 40 wt%): 50 parts by weight were mixed to prepare a coating liquid.

Next, this coating liquid is subjected to degreasing treatment and chromate treatment (
Chromic anhydride aqueous solution applied, dried at 195°C for 30 seconds, coated with a bar coater on a Zn-12%Ni plated steel plate (plating thickness 20g/so2) with a total chromium content of 150mg/m2, and heated at a furnace temperature of 200°C. By baking for 1 minute, 5iO
A rust-preventive steel plate was produced in which a coating layer was formed with y/urethane resin=0.40 and an average thickness of 1.5 μm.

Regarding the rust-proof steel plate manufactured in this way, (1) 3
Film adhesion test after coating (2) Film peelability during processing and corrosion resistance test after processing were conducted.

(I) Film adhesion test after 3 coats The rust-preventive steel sheet with excellent workability according to the present invention was coated with a total of 85 μm of cationic electrodeposition paint of 15 μm, an automotive intermediate coat of 35 μm, and an automotive top coat of 35 μm at 50°C. After soaking in hot water for 240 hours, the adhesive tape ends on the second base. As a result, no peeling of the film was observed.

(2) Film removability during processing and corrosion resistance test after processing The film removability during processing was investigated using the drawbead test device shown in FIG.

The tensile speed was 300 mm/min, and the elongation was 20%.

After the test, the adhesive tape peeling test of the sliding part showed that the film peeled off was less than 0.1 g/m''.

The corrosion resistance after this drawbead test was investigated by the cycle test shown below.

A cycle of salt water spray test (35° C. x 4 hours) - drying (60° C. x 2 hours) - wet (50° C. x 2 hours) - salt water spray test was carried out for 8 hours/1 cycle.

The maximum corrosion depth per 210 cm' of sliding portion after 200 cycles was 75 μm.

2 Comparative Example I Using an aqueous acrylic emulsion (solid content 30%), treated by the same method as Example 1, average film thickness 1.5μ
m organic composite silicate (Sift/acrylic tree [1-
0,40) A film was formed.

A performance test was conducted in the same manner as in Example 1.

(1) Film adhesion test after 3 coats 75% of the film was peeled off.

(2) Film removability during processing and corrosion-resistant film removability after processing 3.5 g/m' maximum corrosion depth
560 μm Example 2 Aqueous urethane emulsion (solid content 30%), 10
0 parts by weight colloidal silica (SiOt 40%); 50 parts by weight zinc powder = 60 parts by weight γ-aminopropyltriethoxysilane: 9 parts by weight Distilled water: 300 parts by weight were mixed to prepare a broth.

Chromate treatment was carried out in the same manner as in Example 1, and a composite phosphoric acid film containing 50 wt % zinc powder (average film thickness 3.5 μm) was obtained by coating with a bar coater.

A performance test was conducted using the same method as in Example 1 for the rust-proof steel sheet manufactured in this way.

(1) Film adhesion test after 3 coats No peeling of the film was observed.

(2) Film peelability during processing and corrosion resistance test after processing Film peeling 'j1 0. Ig/m' or less Maximum corrosion depth 20 μm Example 3 Solvent-based polyurethane resin (solid content IO%): 10
0 parts by weight Fine powder 5iO2 (average particle size 0.5 μm): 5ff
A coating liquid was prepared by mixing 1 part of IF and 100 parts by weight of medyl sulfur amide.

Next, this Q solution was deoxidized and chromated (chromic anhydride and colloidal silica mixed solution applied, 200°C
Zn-12%Ni plated steel plate with a total chromium content of 50 mg/m after drying for 30 seconds (coated with a bar coater to a plating thickness of 20 g/m and baked at a furnace temperature of 200°C for 1 minute to form 5iOy/urethane resin) -0.5, a rust-preventive steel plate with a film layer of average film thickness = 0.8 μm was manufactured.

The rust-proof steel sheet manufactured in this way was subjected to a shear test as described below.

(I) Film adhesion test after 3 coats The anticorrosive steel sheet according to the present invention, which has excellent processing properties, was coated with a total of 85 μm of cationic electrodeposition paint of 15 μm, automotive intermediate coating of 35 μm, and the same top coat of 35 μm. After immersion in warm water at ℃ for 240 hours, a 2 mm thick drying tape test was conducted.

As a result, no peeling of the film was observed.

(2) Film removability during processing and corrosion resistance test after processing The film removability during processing was investigated using the drawbead test device shown in FIG.

Tensile speed 300 mm/ff1in, elongation 20%
And so.

After the test, the amount of film peeled off from the adhesive tape peeling test of the sliding part was 0.1 g/m'' or less.

An example of corrosion resistance after this drawbead test! The evaluation was carried out using the same cycle test as that carried out in .

The maximum erosion depth per 210 cm of sliding portion after 200 cycles was 85 μm.

[Effects of the Invention] As explained above, since the rust-proof steel plate with excellent workability according to the present invention has the above-mentioned configuration, it is a rust-proof steel plate with excellent film adhesion during processing.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a drawbead test device. No.1 Power 300 people

Claims (2)

[Claims] (1) A protective film with excellent workability characterized by having a coating layer mainly composed of a composite material or mixed material of urethane resin and silicon dioxide on the zinc-based plating layer provided on the steel sheet. Rusty steel plate. (2) On top of the zinc-based plating layer provided on the steel plate, a film layer whose main component is a composite material or mixed material of urethane-based resin and silicon dioxide containing zinc powder is provided. Rust-proof steel plate with excellent workability.