JPS61227178A - Surface treated steel sheet having superior lubricity - Google Patents

Abstract

PURPOSE:To obtain a surface treated steel sheet having superior lubricity and high resistance to working by successively forming a chromate film and an acrylic resin film contg. a solid lubricant on the surface of a steel sheet. CONSTITUTION:When a chromate film and an acrylic resin film having superior corrosion resistance and adhesion are successively formed on the surface of a steel sheet, a solid lubricant is incorporated into the acrylic resin film so as to improve the lubricity of the film, ad a surface treated steel sheet having superior resistance to working and undergoing working without scratching or stripping is obtd. The proper amount of the solid lubricant in the acrylic resin film is 3-10pts.wt. per 100pts.wt. resin. Graphite, MoS2 or a mixture thereof is most suitable for use as the solid lubricant and the preferred average particle size of the solid lubricant is 0.3-1.0mum.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a surface-treated steel sheet in which a resin film containing a solid lubricant is formed to improve the lubricity of the resin film.

(Prior art) Steel sheets such as cold-rolled steel sheets and galvanized steel sheets are generally left unpainted for a considerable period of time from the time they are manufactured until they become final products, unless they are made into painted steel sheets, and sometimes they are formed. It is done without painting.

However, if steel plates such as cold-rolled steel plates and plated steel plates are left unpainted for a long period of time, they will rust and become unusable. For this reason, anti-corrosion treatment is generally applied as a post-treatment during manufacturing. Chromate treatment was generally used as the conventional anti-corrosion treatment, but
The chromate film has good adhesion to paint immediately after formation, but if left for a long time, the adhesion to paint will decrease.
If molded, it will be easily destroyed. For this reason, in recent years, it has been practiced to form a resin film with excellent corrosion resistance and paintability on the Chromate-F film by treating it with an aqueous solution of a water-dispersible or water-soluble resin after the chromate treatment.

(Problems to be Solved by the Invention) However, even if a resin film is formed in this way, the conventional resin film will be scratched or peeled off when a steel plate is subjected to roll 7 ohm processing or press processing. Molding processability was still insufficient.

(Measures for solving problems and problems a) Therefore, the present inventors conducted various studies to improve the molding resistance of the resin film. They discovered that adding a lubricant was sufficient.

That is, the present inventors have developed a surface-treated steel sheet with excellent lubricity, characterized in that a chromate film is formed on the surface of the steel sheet, and an acrylic resin film containing a solid lubricant is formed on the chromate film. was successfully developed.

In the present invention, the resin coating is made of acrylic because the acrylic resin coating has excellent corrosion resistance and water injection properties, and rust does not occur on the steel surface even if left unpainted for a long period of time. Moreover, the film hardness is suitably high, it is not damaged during molding, and it also has excellent adhesion to the amate film and the paint film.

This acrylic resin film may be made of a single acrylic resin, but it may also be one in which additives are added within a range that does not impair processability to improve corrosion resistance, coating adhesion, weldability, etc. Water-soluble or water-dispersible inorganic substances are suitable as this additive. For example, metal sols (e.g. alumina sol, turconia sil, magnesia sol, titania sol, silica sol, etc.) are used to improve corrosion resistance and weldability.
Also, by adding irregularities to the surface of the film to enhance the anchor effect, it is easy to apply! Silica colloid, titanium dioxide, aluminum silicate, barium carbonate,
Calcium carbonate, clay, talc, barium sulfate, diatomaceous earth, powdered silica, etc. may be added. The appropriate thickness of the resin film is 0.1 to 2.5 microns.

In addition, in the present invention, solid lubricants can also be used, such as liquid ones (for example, synthetic lubricating oil) or semi-solid ones (for example, wax). This is because they are inferior to solid lubricants in terms of dispersibility and stability.

There are various solid lubricants, but it is preferable to use one that has good water dispersibility, is inexpensive, and does not reduce the corrosion resistance, adhesion, weather resistance, etc. of the film even if it is included in the film. What is more preferable than an organic solid lubricant is 8! These are solid lubricants such as molybdenum disulfide, tungsten disulfide, boron nitride, graphite, and graphite heptadide, and molybdenum disulfide and graphite have no reactivity with additives in the film. Cheap and preferable. These solid lubricants may be used in combination.

As shown in the attached drawing, as the solid lubricant content in the resin film increases, the dynamic friction coefficient decreases and the lubricity during processing improves, but the solid lubricant content increases with respect to 100 parts by weight of the resin. If the amount is less than 3 parts by weight, the effect of addition is not very noticeable.
If the amount exceeds 10 parts by weight, the adhesion of the film to the steel plate will decrease and the dispersibility in the treatment liquid will deteriorate, causing the solid lubricant to settle or the treatment liquid to gel. Therefore, the content of solid lubricant is 3 parts by weight per 100 parts by weight of resin.
It is preferable to adjust the amount to 10 parts by weight.

The average particle size of the solid lubricant is preferably 0.3 to 1.0 μm. This means that if the average particle size is less than 0.3μ,
This is because the solid lubricant does not protrude much from the surface of the resin film, so it has little lubricating effect.On the other hand, if it exceeds 1.0μ, the smoothness of the film will be impaired and it will be difficult to disperse it into the processing liquid.

Note that the chromate film used in the present invention may be any known one. For example, known amate films include those formed by reactive chromate treatment (including reinforced chromate treatment in which an etching agent is added to chromic acid), and those formed by Norrinse's coating type chromate treatment (in which organic resins or inorganic substances are added). ) or by electrolytic chromate treatment, either of these may be used, or a combination thereof may be used.

Next, the present invention will be explained with reference to examples.

(Example) Ethyl orthosilicate after adding water to 85% phosphoric acid 59
09 Ascending γ-7 Minoprobyl triethoxysilane 59
was slowly added under stirring, hydrolyzed at a temperature of 30°C, and water was added to bring the total volume to 308 ml, thereby converting the alkyl silicate hydrolyzate and the alkoxysilane hydrolyzate into 5i02 and about 46.89 ml respectively. l
A slightly cloudy aqueous solution having an eOyoC/about 4,49 le was obtained.

Next, to this aqueous solution 1009, the following cationic resin aqueous dispersion, namely epoxy polybutadiene with a molecular weight of about 1000 (trade name 0F-100017 manufactured by Deka Argus) and polyethyleneimine with a molecular weight of 300 were added. After the reaction, neutralize with acetic acid, then adjust the pH to 2 with phosphoric acid.
．． An aqueous dispersion of water-dispersible epoxy If resin containing cationic nitrogen of 2.3 mmol/9 and adjusted to a concentration of 109 was added as a solid content.

Subsequently, water was added to bring the total volume to 2,001. The aqueous solution prepared here contains an alkyl silicate hydrolyzate and an alkoxysilane hydrolyzate, respectively.
It contained about Z3.49 le oyo (7 about 2.297e, the cationic resin also contained 509/e, and the pH was 2.3.

Furthermore, the following amphoteric ionic resin aqueous dispersion, i.e., 40% methyl methacrylate and 50% butyl 7 acrylate, was added to 500 ml of this cationic resin-added aqueous solution.
After reacting ethylene amine with an acrylic terpolymer having a molecular weight of approximately 200,000 and consisting of 10% acrylic acid,
An aqueous dispersion of a water-dispersible acrylic resin (containing cationic nitrogen of 1.2 mmol/9 and carboxyl group of 0.2 mmol/9) neutralized with phosphoric acid was added as a solid content of 709 g. The condensate was added to bring the total volume to 9,001. The aqueous solution prepared here contains a furkyl silicate hydrolyzate and an alkoxysilane hydrolyzate.
The cationic resin and the zwitterionic resin contained a total of about 105,59/e gold. Furthermore, the pH was 2.5. Different solid lubricants were added to the resin dispersion prepared as above, and the following three types of treatment liquids were prepared.
) A surface-treated steel sheet was manufactured by processing.

Treatment liquid (1) 048 100 parts by weight of molybdenum disulfide L (trade name: Molycolloid CF626, manufactured by Nippon Graphite Industries Co., Ltd.)
~15 parts by weight addition J! I! [(2> Molybdenum disulfide (same as above) and graphite [trade name Oil Hi] for 100 parts by weight of resin G307, Nippon Graphite Industries (
1 to 15 parts by weight of the mixture with J! ! liquid(
3) Graphite [trade name Arguis F3] per 100 parts by weight of resin
3G, added 1 to 15 parts by weight of 1 manufactured by Nippon Graphite Industries Co., Ltd.
The manufacturing process and the formation of the amate film were as follows.

(a) Manufacturing process Steel plate → Degreasing → Applying chromate treatment resin film treatment liquid → Drying (150°C, 10 seconds) (B) Formation of chromate film Chromic anhydride 209/6, N112SIF@1
9 le, immersed in a 40° C. treatment solution for 5 seconds and then roll squeezed. Tables 1 and 2 show the coefficient of dynamic friction, lubricity during processing (roll 7 ohming property, hat bending property), and adhesion of the resin film of the surface-treated steel sheets produced as described above. . In addition, roll 7 ohming characteristics,
Hat bendability was evaluated based on the following criteria.

◎ Film not damaged at all O Film slightly damaged Δ Film significantly damaged × Film significantly damaged The adhesion of the resin film was investigated using the DuPont impact test and evaluated according to the following criteria.

◎ The film did not peel off at all O The film slightly peeled Δ The film peeled off considerably × The film clearly peeled off As is clear from Tables 1 and 2, the surface-treated steel sheets of the present invention As the solid lubricant content in the resin film increases, the coefficient of dynamic friction decreases, and the degree of damage to the resin film during processing decreases. However, if the content of the lubricant exceeds 10 weight parts to #jJJ11oo parts by weight, the adhesion of the resin film becomes poor.

(Effects) As described above, the surface-treated steel sheet of the present invention has excellent lubricity of the resin film, so even if it is subjected to roll 7-ohming or press working, the rJf fat peeling film will not stick or the resin film will peel off. There's nothing to do. Therefore, corrosion resistance will not be impaired even if painted after molding.

[Brief Description of the Drawings] The attached drawing is a graph showing the relationship between the solid lubricant content of the acrylic resin film and the coefficient of dynamic friction in the surface-treated steel sheets of the present invention. Attached drawing

Claims (6)

[Claims] (1) A surface-treated steel sheet with excellent lubricity, characterized in that a chromate film is formed on the surface of the steel sheet, and an acrylic resin film containing a solid lubricant is formed on the chromate film. (2) The surface-treated steel sheet with excellent lubricity according to claim 1, wherein the acrylic resin film contains 3 to 10 parts by weight of a solid lubricant per 100 parts by weight of resin. (3) The surface-treated steel sheet with excellent lubricity according to claim 1, wherein the solid lubricant is graphite. (4) The surface-treated steel sheet with excellent lubricity according to claim 1, wherein the solid lubricant is molybdenum disulfide. (5) The surface-treated steel sheet with excellent lubricity according to claim 1, wherein the solid lubricant is a mixture of graphite and molybdenum disulfide. (6) The surface-treated steel sheet with excellent lubricity according to claim 1, wherein the solid lubricant has an average particle size of 0.3 to 1.0 μm.