KR960013479B1 - Weldable black steel sheet with low-gloss appearance - Google Patents

Abstract

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Description

Weldable Low Gloss Black Steel Sheet

1 is a graph showing the effect of particle size of the organic resin particles blended with black film on the fingerprint.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low gloss black steel sheet excellent in weldable and black appearance suitable for household acoustic and OA equipment, interior decoration, automotive parts, building materials and the like.

In recent years, there is an increasing demand for black steel sheets that are weldable and have excellent appearance in the fields of home acoustics and OA equipment. For this reason, the development of the blackening process of the steel plate is tried variously. In addition, the higher glossiness of the consumer, the less gloss appearance is preferred, or in the process of forming and assembling the black steel sheet, it is necessary to be inconspicuous even if the fingerprint of the operator's hand is attached. Demands are rising.

Conventionally, as a method for forming a black film on a steel sheet, there are generally the following.

(a) A method of coating a resin film containing black pigment such as carbon black with a film thickness of several tens of micrometers by spraying or roll coater or the like.

(b) A method for forming a black film by reacting or electroplating the plating layer itself, which is previously formed as a film.

(1) A method for obtaining a black chromate film by a chromate bath containing Ag ions (Japanese Patent Laid-Open No. 58-193376).

(2) A method of depositing a black resin coating composed mainly of carbon black (Japanese Patent Laid-Open No. 56-62996).

(3) A method of anodizing after Zn-Co, Ni or Mo alloy electroplating (JP-A 61-38276).

(4) A method of obtaining a black appearance by immersion treatment, spray treatment, and anodization in a Zn-Ni alloy-coated steel sheet containing a nitric acid or nitric acid-containing bath (Japanese Patent Application No. 62-30262).

(5) A method of forming a black plated film by cathodic treatment (for example, Japanese Patent Laid-Open No. 62-263995).

(6) A method of depositing a metal having a higher potential by performing substitution plating on Zn or Zn alloy plating (for example, Japanese Patent Laid-Open No. 62-89879).

(C) A method of applying a treatment solution in which an organic dye is added to an aqueous solution of potassium water glass on the surface of zinc or zinc plated for the purpose of corrosion resistance and adhesion (JP-A 55-30593).

However, these prior arts have the following problems.

First, although the method of (a) is a general coating method, since the coating film thickness for exterior is a single layer and is normally 10 micrometers, welding is impossible.

In addition, the black imparting agent in the coating film is carbon black, and in the case of coating with a film thickness within the weldable range, even if the black pigment concentration is increased to the limit as the coating material, the blackness is insufficient, and it is difficult to obtain a sufficient black film by the coating film alone. Do.

That is, in the conventional black imparting agent, it was impossible to obtain sufficient blackness at the film thickness within the weldable range.

Moreover, the following problems also exist about the various methods of (b).

First of all, the method of (1) is not suitable for continuous processing of the strip (5 seconds or less) because the production cost is high because the Ag ion is contained during the treatment, and the processing time required for the blackening is long for several seconds.

In the method of (2), the black coating has insufficient processability, and since the carbon black is a conductive pigment, the black coating has electrical conductivity, and as a result, the corrosion resistance is insufficient. Moreover, blackness is insufficient.

Both of the methods (3) and (4) are uneconomical because they elute some of the pre-formed platings during the black treatment, and the metal ions eluted from the plating deteriorate the blackening treatment, which is large in continuous operation. It becomes a problem.

In addition, the method of (3) is limited to Zn-Co, Ni, and Mo-based alloy plating, and the method of (4) is limited to Zn-Ni alloy plating. There is this.

Moreover, the method of (5) has a problem that the workability of a black film is inadequate. In the method of (6), the adhesion of the black film is insufficient, and since a metal with a lower potential is formed on the lower nonmetal (Zn or Zn alloy) plating, there is a problem that the corrosion resistance is lowered.

Next, the method of (c) is not intended to provide a film having excellent blackness, nor is it intended to impart weldability since the film thickness and the like are not specified. In addition, since potassium water glass is used as the base material of the coating, the coating after curing is insufficient in lubricity at the time of press working, and is not suitable for steel sheets for home appliances, office equipment and the like.

In addition, none of the above methods aims to obtain a low gloss black gloss film, and the black films obtained by the respective blackening treatment methods each have their own gloss.

The present invention has been made to solve the above problems, and because it imparts weldability which was impossible with a conventional black coating film (coating film by the method of (a) above) using black pigment such as carbon black as a black imparting agent, In order to provide an excellent black appearance within the range of weldable film thickness, and to provide a low gloss (no gloss) and a high-quality appearance, and to provide a black steel plate that is not noticeable even when touched by hand. do.

Moreover, the 2nd object of this invention is to provide the black steel plate excellent also in corrosion resistance, adhesiveness, and workability in addition to the outstanding low gloss black appearance.

In addition, when black films are formed on both sides of the zinc-based plated steel sheet, problems such as a decrease in weldability due to a black film having no electrical conductivity and a high production cost are caused.

Particularly, when assembling after processing black steel sheet, it is necessary to use the welding machine with small setting pressure limit and welding current during soft welding. The black steel sheet which is more excellent in weldability is calculated | required in the site | part which requires weldability.

A third object of the present invention is to provide a black steel sheet which is excellent in weldability and can be manufactured at low cost as well as a low gloss black appearance.

In order to achieve the above first and second objects, the present invention has the following configuration.

(1) A chromate film of 1 to 200 mg / m2 of chromium deposition (in terms of metal chromium) is formed on the surface of the zinc or zinc-based alloy plated steel sheet. A weldable low gloss black steel sheet having a black coating comprising 1 to 200 parts by weight of an organic solvent soluble black dye as a black imparting agent, and 1 to 150 parts by weight of organic resin particles.

(2) A chromate film of 1 to 200 mg / m2 of chromium deposition (metal chromium equivalent) is formed on the surface of the zinc or zinc-based alloy plated steel sheet, and an organic solvent-soluble thermosetting resin is used as the gas resin on the upper portion of the chromate film. A black film containing 1 to 200 parts by weight of organic solvent-soluble black dye as a black imparting agent, and 1 to 150 parts by weight of organic resin particles and 1 to 100 parts by weight of inorganic fine particles are added to 100 parts by weight of the gas resin. Weldable low gloss black steel sheet.

(3) A chromate film of 1 to 200 mg / m2 of chromium deposition (in terms of metal chromium) is formed on the surface of the zinc or zinc-based alloy coated steel sheet, and an organic solvent-soluble thermosetting resin is used as a gas resin on the upper portion of the chromate film. A black film containing 1 to 200 parts by weight of an organic solvent soluble black dye as a black emulsifier, and 1 to 150 parts by weight of organic resin particles and 1 to 100 parts by weight of a solid lubricant as Weldable low gloss black steel sheet.

(4) A chromate film of 1 to 200 mg / m2 of chromium deposition (in terms of metal chromium) is formed on the surface of the zinc or zinc-based alloy plated steel sheet, and an organic solvent-soluble thermosetting resin is used as a gas resin on top of the chromate film. 1 to 200 parts by weight of organic solvent-soluble black dye is blended as a black imparting agent with respect to 100 parts by weight of gaseous resin, 1 to 150 parts by weight of organic resin particles, 1 to 100 parts by weight of inorganic fine particles, and 1 solid lubricant. Weldable low gloss black steel sheet with a black coating blended to 100 parts by weight.

(5) The low-gloss black steel sheet of (2) or (4), wherein the inorganic fine particles in the black film contain one or two or more selected from the group consisting of silica, extender pigment, poorly soluble chromate, and carbon black. Weldable low gloss black steel sheet.

(6) In the low-gloss black steel sheet of the above (3) or (4), as a solid lubricant in the black coating, polyelpine wax, paraffin wax, fluororesin compound, fatty acid amide compound, metal soap, molybdenum disulfide, graphite A weldable low gloss black steel sheet containing one or two or more selected from the group consisting of graphite fluoride, boron nitride and polyalkylene glycol.

Moreover, the structure for obtaining the more outstanding gloss removal effect and fingerprint resistance is as follows.

(7) A chromate film of 1 to 200 mg / m2 of chromium deposition (metal chromium equivalent) is formed on the surface of the zinc or zinc-based alloy plated steel sheet, and an organic solvent-soluble thermosetting resin is used as the gas resin on the upper portion of the chromate film. With respect to 100 parts by weight of the gas resin, the organic solvent soluble black dye which is a black imparting agent: 1 to 200 parts by weight, organic resin particles having an average particle diameter of 1 to 25 μm: 10 to 150 parts by weight of a film thickness of 0.3 to 5.0 μm Weldable low gloss black steel with a black coating.

(8) A chromate film of 1 to 200 mg / m2 of chromium deposition (metal chromium equivalent) is formed on the surface of the zinc or zinc-based alloy plated steel sheet, and an organic solvent-soluble thermosetting resin is used as the gas resin on the upper portion of the chromate film. Organic solvent-soluble black dye as a black imparting agent: 1 to 200 parts by weight, organic resin particles having an average particle diameter of 1 to 25 μm, 10 to 150 parts by weight, and wet silica: 1 to 30 parts by weight based on 100 parts by weight of the gas resin. Weldable low gloss black steel sheet with a black film with a blend thickness of 0.3-5.0 µm.

(9) A chromate film of 1 to 200 mg / m2 of chromium deposition (metal chromium equivalent) is formed on the surface of the zinc or zinc-based alloy plated steel sheet, and an organic solvent-soluble thermosetting resin is used as a gas resin on the upper portion of the chromate film. 1 to 200 parts by weight of an organic solvent soluble black dye as a black imparting agent, to an organic resin particle having an average particle diameter of 1 to 25 μm, and 10 to 150 parts by weight and a fluorine compound particle: 1 to 40 parts by weight based on 100 parts by weight of a gas resin. Weldable low gloss black steel sheet with a black coating with a thickness of 0.3-5.0 µm.

(10) A chromate film of 1 to 200 mg / m2 of chromium deposition (metal chromium equivalent) is formed on the surface of the zinc or zinc-based alloy plated steel sheet, and an organic solvent-soluble thermosetting resin is used as a gas resin on the upper portion of the chromate film. Organic solvent-soluble black dye which is a black imparting agent with respect to 100 parts by weight of gaseous resin: 1 to 200 parts by weight of organic solvent-soluble black dye which is a black imparting agent: 1 to 200 parts by weight, and an average particle diameter of 1 to 25 μm. Weldable low-gloss black steel sheet with a black film with a film thickness of 0.3-5.0 µm in which organic resin particles: 10 to 150 parts by weight, wet silica: 1 to 30 parts by weight, and fluorine compound particles: 1 to 40 parts by weight.

(11) The low-gloss black steel sheet according to any one of (7) to (10), wherein the black coating contains 1 to 40 parts by weight in total of 100 parts by weight of at least one of poorly soluble chromate and dry silica. Weldable low gloss black steel sheet.

(12) The low gloss black steel sheet according to any one of (7) to (10), wherein the black coating is weldable containing at least one of polyethylene wax and paraffin wax containing 1 to 40 parts by weight in total with respect to 100 parts by weight of the gas resin. Low gloss black steel plate.

(13) The weldable low gloss black steel sheet according to any of (7) to (10), wherein the black steel sheet contains the components of the following (A) and (B).

(A) 1 to 40 parts by weight of at least one of poorly soluble chromate and dry silica in total with respect to 100 parts by weight of the gas resin.

(B) 1 to 40 parts by weight of at least one of polyethylene wax and paraffin wax in total with respect to 100 parts by weight of gas resin

Moreover, in each black steel plate of said (1)-(13), more preferable embodiment is as follows.

(14) The low-gloss black steel sheet according to any one of (1) to (13), wherein the organic resin particles to be blended in the black film are urethane resin particles, silicone resin particles, epoxy resin particles, amino resin particles, and acrylic resin particles. A weldable low gloss black steel sheet containing one or two or more selected from the group consisting of acrylonitrile resin particles, acrylic-urethane resin particles, polyamide resin particles, polyester resin particles and polypropylene resin particles.

(15) The low gloss black steel sheet according to any one of (1) to (13), wherein the black urethane resin particles, the black silicon resin particles, the black epoxy resin particles, the black amino resin particles, and the black acryl are used as the organic resin particles in the black film. Resin particles, black acrylonitrile resin particles. A weldable low gloss black steel sheet containing one or two or more selected from the group of black acrylic-urethane resin particles, black polyamide resin particles, black polyester resin particles, and black polypropylene particles.

(16) The low gloss black steel sheet according to any one of (1) to (13), wherein the black dye in the black coating is one selected from the group of organic solvent-soluble azo dyes and organic solvent-soluble azine dyes, or Two or more weldable low gloss black steel plates.

(17) The weldable low gloss black steel sheet according to any one of (1) to (13), wherein the black dye in the black coating is an organic solvent-soluble azo metal complex dye.

(18) The weldable low gloss black steel sheet according to any one of (1) to (13), wherein the black dye in the black coating is a mixture of an organic solvent-soluble azo metal complex dye and a phthalocyanine dye.

Further, in order to achieve the third object, the core of the black steel sheet of the present invention forms a two-layer coating of a chromate coating and a black coating on one side of the lead-based plated steel sheet, and makes the other surface a chromate single-layer coating. In addition, by adding a function such as anti-fingerprint, high corrosion resistance, etc. to the coating on the chromate single layer side, if necessary, the anti-fingerprint and long-term corrosion resistance in assembling home appliances.

That is, such a black steel sheet has the following configuration.

(19) In the low-gloss black steel sheet in any one of (1) to (18), the black film is formed on only one side (one side) of the steel sheet, and the amount of chromium deposition (metal chromium equivalent) is 10 to 120 mg on the other side of the steel sheet. Weldable black steel plate having a chromate film of only / m < 2 >

(20) In the low-gloss black steel sheet of the above (20), the chromate film on the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions and trivalent Cr ions, and metal chromium of hexavalent Cr ions and trivalent Cr ions. The weldable black steel plate which is a chromate film obtained by apply | coating the chromate processing liquid whose weight ratio (hexavalent Cr ion / trivalent Cr ion) in terms of conversion is 40/60-80/20, and heats and dries it.

(21) In the low-gloss black steel sheet of (19), the chromate film on the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions and silica sol, and the hexavalent Cr ions and trivalent Cr ions. The weight ratio (hexavalent Cr ions / 3 valent Cr ions) in terms of metal chromium is 40/60 to 80/20, and the weight ratio (silica sol / total Cr amount) of silica sol and total chromium (metal chromium) is 1 / The weldable black steel plate which is a chromate film obtained by apply | coating the chromate processing liquid of 2-8 / 1, and heating and drying this.

(22) In the low-gloss black steel sheet of (19), the chromate coating on the steel plate surface on which only the chromate coating is formed contains a hexavalent Cr ion, a trivalent chromium ion, and an aqueous resin, and the hexavalent Cr ion and the trivalent Cr ion. The weight ratio (hexavalent Cr ions / 3 valent Cr ions) in terms of metal chromium is 40/60 to 80/20, and the weight ratio (aqueous resin / total Cr amount) between the aqueous resin and the total chromium amount (in terms of metal chromium) is 1 /. The weldable black steel plate which is a chromate film obtained by apply | coating the chromate process liquid of 20-40 / 1, and heating and drying this.

(23) In the low-gloss black steel sheet described in (19), the chromate film on the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, silica sol, and an aqueous resin, and hexavalent Cr ions and trivalent. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) in terms of metal chromium to Cr ions is 40/60 to 80/20, weight ratio of silica sol to total chromium (metal chromium equivalent) (silica sol / total Cr) ) Is coated with a chromate treatment liquid having 1/2 to 8/1, weight ratio (aqueous resin / total Cr amount) of the aqueous resin and the total amount of chromium (in terms of metal chromium), 1/20 to 40/1, and heating it. A weldable black steel sheet which is a chromate coating obtained by drying.

(24) In the low-gloss black steel sheet described in (19), the chromate film on the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, trivalent PO ₄ ions, and divalent Zn ions. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) of Cr ions and trivalent Cr ions between 40/60 to 80/20, between trivalent PO ₄ ions and total chromium (metal chromium equivalent) The weight ratio (trivalent PO ₄ ions / total Cr content) is 1/30 to 2/1, and the weight ratio (divalent Zn ion / hexavalent Cr ion) of divalent Zn ions and hexavalent Cr ions (metal chromium equivalent) The weldable black steel plate which is a chromate film obtained by apply | coating 1 / 40-2 / 3 chromate treatment liquid, and heating and drying this.

(25) In the low-gloss black steel sheet of (19), the chromate film on the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, silica sol, trivalent PO ₄ ions, and divalent Zn ions. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) between 40/60 to 80/20, silica sol and total chromium (metal chromium equivalent) Weight ratio (silica sol / total Cr amount) is 1/2 to 8/1, and weight ratio (trivalent PO ₄ ions / total Cr amount) between trivalent PO ₄ ions and total chromium amount (metal chromium equivalent) is 1/2 Weight ratio (trivalent PO ₄ ions / total Cr content) of ˜8 / 1, trivalent PO ₄ ions and total chromium (metal chromium equivalent) 1/30 to 2/1, divalent Zn ions and hexavalent Cr ions The weldable black steel plate which is a chromate film obtained by apply | coating the chromate processing liquid whose weight ratio (divalent Zn ion / hexavalent Cr ion) with (metal chromium conversion) is 1 / 40-2 / 3, and heating and drying this.

(26) In the low-gloss black steel sheet of (19), the chromate film on the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, aqueous resins, trivalent PO ₄ ions, and divalent Zn ions. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) of 40/60 to 80/20 as the amount of metal chromium between hexavalent Cr and trivalent Cr ions, and the amount of aqueous resin and total chromium (metal chromium) Weight ratio (aqueous resin / total Cr amount) is 1/20 to 40/1, and weight ratio (trivalent PO ₄ ion / total Cr amount) between trivalent PO ₄ ions and total chromium amount (metal chromium equivalent) is 1/30 Apply a chromate treatment solution having a weight ratio (divalent Zn ion / hexavalent Cr ion) of ˜2 / 1, divalent Zn ion and hexavalent Cr ion (in terms of metal chromium) of 1/40 to 2/3. A weldable black steel sheet which is a chromate coating obtained by heating and drying.

(27) In the low-gloss black steel sheet of (19), the chromate coating on the steel plate surface on which only the chromate coating is formed is hexavalent Cr ions, trivalent Cr ions, silicalcazole, aqueous resins, trivalent PO ₄ ions, and divalent Zn ions. 40-60 to 80/20 in weight ratio (hexavalent Cr ions / 3 valent Cr ions) in terms of metal chromium between hexavalent Cr ions and trivalent Cr ions, and the amount of resin and total chromium (metal chromium) ) and the weight ratio (aqueous resin / I Cr amount) is 1 / 20-40 / 1, a trivalent chromium in terms of PO4 ions and around) the weight ratio (trivalent PO ₄ ions / I Cr amount of) 1 / 30-2 A chromate treatment liquid having a weight ratio (divalent Zn ion / hexavalent Cr ion) of / 1, divalent Zn ions and hexavalent Cr ions (metal chromium equivalent) of 1/40 to 2/3 is applied and heated and A weldable black steel sheet which is a chromate coating obtained by drying.

EMBODIMENT OF THE INVENTION Hereinafter, the detail of this invention and the reason for limitation are demonstrated.

The black steel sheet of the present invention is based on a zinc plated or zinc alloy plated steel sheet, which is based on a chromate film on the surface thereof, and a thermosetting resin of organic solvent soluble on top thereof. It has a black film made of a composition containing a mating agent.

Here, the black dye in this invention includes what shows black by only the same kind of molecule in the chemical structure of a molecule, and what shows black by mixing several types of dyes from which the chemical structure of a molecule differs.

Zinc-based galvanized steel as starting material is galvanized steel sheet, zinc-iron alloy coated steel sheet, zinc-nickel alloy coated steel sheet, zinc-manganese alloy coated steel sheet, zinc-aluminum alloy coated steel sheet, zinc-cobalt-chromium alloy coated steel sheet Those in which one, two or more kinds of elements such as Ni, Fe, Mn, Co, Al, and Cr are added to the plating component of these arbitrary steel sheets can be used.

Further, a steel sheet having a dispersion plating in which the particulate resin, silica, chromium compound, or the like is vacated during any of the above platings can be used.

Moreover, the composite plating steel plate which performed two or more layers of the same or different types of plating as mentioned above may be sufficient. For example, the plating film which provided two or more layers of Fe-Zn alloys with different Fe content can be used as the base.

In addition, from the viewpoint of blackness, the same black coating is obtained regardless of the type of base steel sheet, and therefore it is possible to use a hot rolled steel sheet or a cold rolled steel sheet without a plating coating as a starting material, and for the same reason, a stainless steel sheet, an aluminum alloy sheet, and a titanium alloy. It is also possible to use a plate as a material.

However, when considering the use of unpainted by forming and processing as black steel sheet for home use, the starting material is preferably the zinc-based plated steel sheet in view of performance such as cost and corrosion resistance, and therefore, the starting material is zinc in the present invention. It is limited to a plated steel sheet or a zinc-based alloy plated steel sheet.

As the plating method of these zinc-based plated steel sheets, any of practical methods may be adopted among electrolytic methods, melting methods, and vapor phase methods.

The chromate coating film by chromic acid treatment is formed in the surface of the abnormal raw material steel plate. In the black steel sheet of this invention, very excellent corrosion resistance can be obtained by combining this chromate film and the black film containing the specific black impregnation agent mentioned later.

This chromate coating is 1 to 200 mg / m 2, preferably 30 to 80 mg / m 2 (above, in terms of metal chromium) as the chromium deposition amount (dry).

If the amount of chromium deposited exceeds 200 mg / m 2, the workability and weldability tend to deteriorate. In addition, when the amount of chromium deposited is less than 1 mg / m 2, the coating may be uneven, which may deteriorate the corrosion resistance. In addition, hexavalent Cr is preferably present in the chromate film. Hexavalent Cr ions have a water-reducing action and, when a steel sheet is damaged, suppress the corrosion therefrom.

The chromate treatment for such a base film may be carried out by any known method such as reaction type, coating type or electrolytic type.

The coated chromate treatment solution is mainly composed of partially reduced chromic acid solution, and, if necessary, organic resins such as water-dispersible or water-soluble acrylic resins, and / or silica particles having a particle size of mμ to several hundred mμ (colloidal silica, fume). Desilica).

In this case, the ratio of trivalent Cr ions / hexavalent Cr ions is preferably 1/1 to 1/3 and the pH is 1.5 to 4.0 (more preferably 2 to 3).

The ratio of trivalent Cr ions / hexavalent Cr ions is controlled at a predetermined ratio using a general organic reducing agent (eg, sugars, alcohols, etc.) or an inorganic reducing agent.

Moreover, you may use any method, such as a roll coater method, an immersion method, a spray method, as a coating type chromate treatment. In the coating type chromate treatment, the coating is dried without washing with water after the chromate treatment.

The drying without washing with water is performed because the hexavalent Cr ions are removed in the usual water washing, and the ratio of trivalent Cr ions / hexavalent Cr ions is maintained as it is, and the corrosion coating is performed by the resin film formed thereon. It is possible to suppress excessive leakage of hexavalent Cr ions under the following conditions, and to effectively maintain the passivation effect for a long time to obtain high corrosion resistance performance.

On the other hand, in the electrolytic chromate treatment, a cathodic electrolytic treatment is carried out in a bath containing one or two or more kinds of anions such as chromic anhydride, sulfuric acid, phosphate fluoride or hydrochloric acid, followed by washing with water and drying to form a film.

Comparing the chromate coatings by the two treatment methods described above, the coated chromate contains more hexavalent chromium in the coating than the electrolytic chromate, and thus has excellent corrosion resistance. Moreover, when heat-treated as described below, the coating is dense and rigid. As a result, the corrosion resistance is better than the electrolytic chromate.

On the other hand, electrolytic chromate has the advantage of having a high degree of completeness of the film, despite the presence or absence of heat treatment, and has an advantage of easy control of the coating amount. In view of corrosion resistance, coated chromate is most preferred.

Next, the components of the black film will be described.

In the present invention, the black coating includes organic solvent-soluble thermosetting resins as gas resins, and organic resin particles (beads) as organic solvent-soluble black dyes and gloss scavengers as black imparting agents. It is characterized by.

In addition, in the present invention, not only the above components but also the solid lubricant for the purpose of eliminating the gloss of the black film and improving the workability, the same as the inorganic lubricant for the purpose of removing the gloss of the black film (in some cases, to further improve the corrosion resistance). It can contain respectively.

In particular, by blending wet silica or fluorine compound particles as a gloss scavenger with organic resin particles having an average particle diameter of 1 to 25 µm, particularly excellent gloss elimination effects and fingerprint resistance can be obtained. .

Further, at least one of polyethylene wax and paraffin wax may be blended for the purpose of improving the workability (lubrication) of the black coating, and at least one kind of poorly soluble chromate and dry silica may be blended for the purpose of improving the corrosion resistance.

In the following description, the blackness of a black film is evaluated by the brightness (L) value. The smaller the value of L, the better the blackness, and the lower the target of the black coating in the present invention. 30, preferably L 25, more preferably L 20.

The L value was measured by a Suga Test Co., Ltd. poly-light spectrophotometer (model MSC).

The function required as a black imparting agent is that it can show sufficient blackness in the weldable film (5 micrometers or less).

Furthermore, when the black imparting agent is mixed with the gas resin in a mixing ratio at which sufficient blackness is obtained, it may not adversely affect other performances required for black coating, such as workability and corrosion resistance.

Commonly used colorants can be broadly classified into inorganic pigments, organic pigments, and dyes. Of these, when inorganic pigments and organic pigments are used in thin coatings of several micrometers or less, the hiding power of pigments is important for blackness. As a black pigment impregnating agent for inorganic pigments, carbon black is the most common among the black pigments due to its low price and the like.

However, this carbon black is different from the case of a film thickness of several 10 占 퐉 like a normal paint, and thus, in a thin film having a thickness of 5 占 퐉 or less, the hiding power is not sufficient, and thus the blackness is insufficient. Since it is an electroconductive pigment, since a black film has electrical conductivity and the corrosion resistance of a steel plate is inferior, it is not suitable.

In addition, other black inorganic pigments such as iron oxide, titanium black and the like also do not have sufficient blackness. Moreover, although aniline black is typical as a black organic pigment, since this also has a low concealment power, sufficient blackness cannot be acquired. Other black organic pigments include perylene black, but this also cannot obtain sufficient blackness.

Moreover, even when combining two or more types of inorganic pigments and organic pigments mentioned above, blackness is not enough.

In contrast, the black dye can impart excellent blackness to the film even at a thin film thickness. Inorganic pigments and organic pigments are particles, which are considered to be black because they absorb visible light. Therefore, in order to obtain good blackness, a certain thickness of the aggregate of particles, that is, the thickness of the coating is required. It seems to be possible. On the other hand, since the black dye is dissolved in water or an organic solvent, it can be dispersed in a dense film in a state where the molecular level is very small, and thus excellent blackness can be given even in a thin film.

Currently, there are thousands of kinds of dyes on the market, but these are broadly classified into two types of classification methods, namely, chemical structural classification method (1) and practical classification method based on dye properties (for example, Published the Organic Chemistry Handbook, Organic Synthetic Chemistry Association).

In the classification method (1) by chemical structure, it is classified by the main structure which causes color development in dye molecules, and it is classified into nitroso dye, nitro dye, azo dye (mono azo dye, disazo dye, tris azo dye, tetrakis azo dye) ), Anthraquinone dyes, indigo dyes, azine dyes, cyanine dyes, phthalocyanine dyes, cytylbene dyes, sulfur dyes, triazole dyes, triphenylmethane dyes, acridine dyes, diphenylmethane dyes, oxazine dyes, and the like. .

On the other hand, in the practical classification method (2) based on the dye properties, direct dyes, acid dyes, basic dyes, acid dyes, metal complex dyes, sulfide dyes, vat dyes, azoic dyes, disperse dyes, reactive dyes, oxidation dyes, fluorescence Brightening dyes and oil-soluble (organic solvent soluble) dyes.

According to the above classification, for example, the dyes classified in the acid dyes by the classification method of 92 are again azo dyes (mono-azo, disazo, tris-azo, tetraazo, tetrakis-azo) and anthraquinones by the classification method of (1). It can be classified into dyes, triphenylmethane dyes, azine dyes and the like.

On the other hand, the color, which is an important characteristic of the dye, is a group having an unsaturated bond (chromophore) such as -CH = CH and -N = N- in its chemical structure and a group having a free electron pair such as -NH ₂ or -OH ( Color tone), the light of a certain wavelength is absorbed, and the light of the wavelength which is not absorbed is caught as a color of the thing with the naked eye, and as a result, various colors of dye exist. In the following "COLOUR INDEX", these colors are classified into yellow, orange, red, violet, blue, green, green tea and black.

By the way, `` COLOUR INDEX (THIRD EDITION Vol. "CI" classified and defined in this "COLOUR INDEX" Generic Name ”.

That is, this "COLOUR INDEX" classification method divides commercial dyes into practical divisions which are roughly the same as the classification of (2) above, then displays color divisions, and classifies each dye having the same chemical structure among them ( Numbered one by one).

Specifically, it is clear that the structural formula "C.I. Constitution Number ”, but most of them describe chemical structural classifications such as azo (monoazo, disazo, etc.), anthraquinone, azine, etc., as described above in most of them.

For example, the black dye in the classification of the acid dye is "C.I. Acid Black ", and among them," C.I. Acid Black "has a specific chemical structure of disazo dye, and" C.I. Acid Black 2 "has a specific chemical structure of azine dye," C.I. Acid Black 3 ”is classified as having a specific chemical structure of disazo dyes, and the colors, properties, uses, and the like are described in each. And this "C.I. Generic Name ”may be contrasted with a trade name of a commercial dye.

As a result of the investigation by the present inventors, it was found that, by blending the organic solvent-soluble black dye with the organic solvent-soluble thermosetting resin, good blackness can be obtained even as a weldable thin film (5 µm or less).

Since these organic solvent soluble black dyes are easily dissolved in organic solvents (e.g., alcohols, cellosolves, esters, ketones), the composition of the black coating can be obtained by mixing them with the organic solvents and the organic solvent soluble thermosetting resins. .

And when it mix | blends as a black grant agent in a black film in this way, even the thin film (5 micrometers or less) of the weldable range shows the outstanding blackness. In addition, since the dye itself has excellent light fastness, there is no problem even if it is used for black steel sheets such as home appliances and office equipment that are illuminated by various light sources. The organic solvent-soluble black dye may be a dye having any structure classified according to classification (1), but azo metal complex dyes, azo dyes, and azine dyes are particularly preferable as described below. In addition, you may mix | blend coloring dyes, such as a phthalocyanine dye.

Black dyes belong to "Black" in the color classification of "COLOUR INDEX". However, using a conventionally known method of subtractive color mixing, a black film may be formed by mixing, for example, three colors of sulfur, red, and purple.

That is, as described above, the black dye to be applied to the present invention not only shows black with only the same kind of molecule in terms of the chemical structure of the molecule, but also shows black by mixing several kinds of dyes having different chemical structures of the molecule.

Therefore, using the principle of subtractive color mixing, it is possible to apply a mixture of several colored dyes belonging to one or two or more of the above-described dyes to produce a black dye.

In addition, in this invention, it cannot be overemphasized that the organic solvent soluble black dye which is not registered in "COLOUR INDEX", for example, the dye which is newly developed and is not yet registered, and mixture of several dye can be used.

Moreover, among the said black dyes, especially the black azo dye of soluble organic solvent is inexpensive, and also favorable blackness can be obtained.

In addition, the present inventors found that by adding a black azo metal complex salt dye, which is one of the black azo dyes, a black film having the most excellent blackness and more excellent light fastness and corrosion resistance than other dyes can be obtained.

This dye is characterized by (1) complex of 1 atom of metal (2: 1 metal complex salt) with 2 molecules of azo dye or complex of 1 atom of metal (1: 1 metal complex salt) with 1 molecule of azo dye. For the structural reasons considered, light stability (light fastness) is superior to other dyes, and ② blackness is superior to other dyes.

Metals capable of forming complex salts with dyes include Cr, Co, Cu, Fe, Al, and the like, but are mainly those of the complex salts with Cr.

The black azo metal complex dye of this organic solvent soluble is "C.I. Among the organic solvent soluble black dyes classified in Solvent Black, it is a complex compound of three kinds of metals such as azo dye and chromium, copper and cobalt, and according to C.I. Generic Name ”as C.I. Solvent Black 6, 22, 23, 25, 28, 29, 30, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45, 47, 48, 49.

Moreover, as mentioned above, it is a black azo metal complex dye of organic solvent soluble (for example, newly developed and not yet registered) which is not registered in "COLOUR INDEX", or a mixture of several types of dyes, It goes without saying that the mixture containing at least one organic solvent soluble black azo metal complex dye can be used.

When such an organic solvent-soluble black azo-based metal complex dye is blended as a black grant agent in the black film, even in a thin film (5 µm or less) in the weldable range, it has a uniform and excellent black appearance, and particularly excellent light fastness. Is obtained.

In addition, by using azo metal complex dyes and phthalocyanine dyes in combination, the color tone of the black film can be adjusted to obtain a beautiful black film.

For example, as shown in the present invention 9 of Example 4, a particularly beautiful appearance can be obtained by blending a yellow azo-based metal complex dye and a blue phthalocyanine dye with the black azo-based metal complex dye as the center.

In addition, the organic solvent-soluble black azine dyes and the organic solvent soluble black azo dyes other than the metal complex salts are inferior to the black azo metal complex dyes, but have superior light fastness when compared to the black medium dyes. Furthermore, since the manufacturing cost is about 5-8% of the organic solvent soluble black azo metal complex dye, the raw material cost of the black film can be reduced as compared with the black steel plate using the organic solvent soluble black azo metal complex dye as a black imparting agent. There is an advantage.

As an organic solvent soluble black azo dye, the above-mentioned "COLOUR INDEX" is "C.I. In the black solvent of the organic solvent soluble classified in "Solvent Black",

C.I. Solvent Black 1, 2, 6, 15, 24, 35 (above, monoazo dyes)

C.I. Solvent Black 3, 4, 39 (above, disazo dye)

C.I. Solvent Black 26, 46, 51 (the number of azo groups in the molecule is unknown)

Etc. In addition, you may use an existing thing or a new thing not registered in "COLOUR INDEX".

The organic solvent-soluble black azo dyes may be used by mixing two or more kinds of them, and the black azo dyes may be mainly used, and the black azo dyes are mixed with dyes belonging to different types on the chemical structural classification. You may use as zero.

As a commercial item, for example,

Neptun Black X60 (C.I. Solvent Black 3; made by BASF)

Neptun A Black X17 (C.I. Solvent Black 46; made by BASF)

Mitsui Oil Black YG-6 (C.I.Solvent Black 39; manufactured by Mitsui Oatsu Senyouo Co., Ltd.)

Etc., and a black film showing excellent blackness can all be obtained.

Moreover, in the thin film (~ 5 micrometer) which can weld an organic solvent soluble black azine dye, it shows the outstanding blackness which is about the same as the organic solvent soluble black azo type metal complex dye. Since the manufacturing cost of this organic solvent soluble black azine dye is about half of that of the organic solvent soluble black azo metal complex dye, the raw material cost of black coating is higher than that of the black steel plate which uses the black azo metal complex dye as a black imparting agent. There is an advantage that can greatly reduce the.

As a black azine dye of soluble organic solvent, the above-mentioned "COLOUR INDEX" is "C.I. Solvent Black is a C.I. Solvent Black 5, 5: 1, 7, 31, 32, 50, and the like.

In addition, you may use an existing thing or a new thing not registered in "COLOUR INDEX". In addition, the organic solvent-soluble black azine dye may be used by mixing two or more kinds, and the black azine dye is mainly used, and a black dye that is mixed with dyes belonging to different kinds in chemical structure classification is blackened. You may use as zero.

As a commercial item of the organic solvent soluble black azine dye, for example,

Basonyl Black X22 (C.I. Solvent Black 5; made by BASF)

Orient Spirit Black SB, (C.I. Solvent Black 5; manufactured by Orient Kagaku Koyokyo Co., Ltd.)

Orient Spirit Black SSBB (C.I.Solvent Black 5; product made by Orient Kagaku Koyokyo Co., Ltd.)

Orient Nigrosine Base EX (C.I. Solvent Black 7; manufactured by Orient Chemical Industries, Ltd.)

Orient Oil Black BS (C.I.Solvent Black 7; product made by Orient Kagaku Koyokyo Co., Ltd.)

Orient Special Black EB (C.I.Solvent Black 7; product made by Orient Kagaku Koyokyo Co., Ltd.)

Sumisol Black AR (C.I.Solvent Black 50; manufactured by Orient Kagaku Koyogyo Co., Ltd.)

It is possible to obtain a black film having a blackness, which is excellent in both.

The black film to which the organic solvent soluble black dye was added is excellent in corrosion resistance as mentioned above, and the corrosion resistance is much more excellent than the black film containing a pigment as a black imparting agent. this is,

① black dye is non-conductive,

② The black dye is distributed uniformly and densely in the black film at the molecular level, and the dye itself has a function as a passive film.

③ It is thought that the black dye distributed uniformly and densely in the black film at the molecular level prevents the permeation of ions into the film and improves the barrier effect of the film.

In addition, the steel sheet having such a black coating has not only a barrier effect by passivation film formation (action of trivalent Cr ions) of the bottom chromate and a corrosion effect by a barrier effect of the resin film itself, but also a barrier effect by the above-described black dye itself. The corrosion resistance is further enhanced, and the self-healing effect of repairing the defects of the passivation film by the hexavalent Cr ions of the underlying chromate to the trivalent Cr ions and the good adhesion of the underlying Zn-based plating-chromate coating-black coating High corrosion resistance can be obtained.

In addition, unlike conventional black treatments involving reactions such as etching type, electrolytic treatment, and substitution plating, there is no deterioration of the bath associated with the treatment, and the type of plating of the base is not limited. Benefits can also be saved.

Next, in the black film of the present invention, the blending ratio of the organic solvent-soluble black dye to 100 parts by weight of the gas resin is 1 to 200 parts by weight, preferably 4 to 120 parts by weight. If it is less than 1 part by weight, the coloring effect of the black dye is insufficient, and if it exceeds 200 parts by weight, undissolved dye remains, which adversely affects the adhesion.

Moreover, the thickness of a black film is 0.3-5.0 micrometers, Preferably it is 0.7-3.0 micrometers. When the film thickness is less than 0.3 µm, the coloring effect of the black dye is insufficient. On the other hand, when the thickness exceeds 3.0 µm, the spot weldability is lowered.

The gas resin of the black film of the steel sheet of the present invention is an organic solvent soluble and a thermosetting resin. The gaseous resin is defined by such a resin for the following reasons. In the case of water-soluble resin, when the organic solvent-soluble black dye is mix | blended, there arises a problem of dissolving this dye inadequately.

For this reason, the gas resin needs to be an organic solvent soluble resin. Moreover, when a thermoplastic resin is used, since the problem arises in the upper flaw resistance of the formed black film, it is necessary to set it as a thermosetting resin.

Examples of the organic solvent-soluble thermosetting resins include acrylic copolymer resins, ilkyd resins, epoxy resins, polybutadiene resins, phenol resins, polyurethane resins, fluororesins (fluoro resins) and mixtures of two or more of these resins, and other monomers. And addition derivatives thereof, or modified derivatives of other resins.

Of these, acrylic copolymer resins, alkyd resins, epoxy resins, fluorine resins and the like are suitable.

The acrylic copolymers are resins synthesized by a solution polymerization method, an emulsion polymerization method or a suspension polymerization method using a common unsaturated ethylenic monomer, methacrylate type, acrylonitrile, styrene, acrylic acid, acrylamide, secret It is obtained by making an unsaturated vinyl monomer suitably mix | mold in order to make hard monomers, such as toluene, an essential component and to give hardness, flexibility, and crosslinkability of resin to this.

The resin may be a resin modified by another alkyd resin, epoxy resin, phenol resin or the like.

Alkyd resins may be known ones obtained by conventional synthetic methods, for example, modified alkyd resins, rosin-modified alkyd resins, phenol-modified alkyd resins, styrenated alkyd resins, silicone-modified alkyd resins, acrylic modified alkyd resins, and oils. Prialkyd resin (polyester resin) etc. are mentioned.

Epoxy resins include straight epoxy resins such as epichlorohydrin type and glycidyl ether type, fatty acid modified epoxy resin (epoxy ester resin), polybasic acid modified epoxy resin, acrylic resin modified epoxy resin, alkyd (or polyester) modified Epoxy resins, polybutadiene modified epoxy resins, phenol modified epoxy resins, amine or polyamine modified epoxy resins, urethane modified epoxy resins and the like can be used.

Known predetermined curing agents are used for these resins. Examples of this curing agent include melamine, blocked isocyanates, urea and the like.

By the way, the black film | membrane which consists only of the above composition shows a glossiness external appearance. If a fingerprint adheres to such a film, since the degree of scattering of light in the fingerprint portion and the degree of scattering of light in a portion without a fingerprint are different, the fingerprint portion is conspicuous, resulting in inferior fingerprinting.

In order to improve such fingerprinting, it is possible to reduce the glossiness of the black film so that the degree of reflection and scattering of light between the fingerprint attachment portion and its surroundings is about the same, thereby making the fingerprint inconspicuous. For this reason, the gloss removal agent was added to the black film, and the effect was examined.

Generally, wet silica (white carbon) is used as a gloss removing agent for paints. In the case where wet silica is added to the black film alone, very fine rough portions are formed on the surface of the film to reduce glossiness, but the black film becomes white and the blackness is significantly lost. In addition, since hydrophilicity is imparted to the film by silica protruding from the surface of the black film, sweat is adsorbed when the fingerprint adheres to this surface, and the fingerprint part appears blacker than the surroundings, and sufficient fingerprint resistance cannot be expected.

As a result of the present inventors' investigation for the purpose of lowering the glossiness of the black film and improving the anti-fingerprint, the present inventors have found that organic resin particles (particularly, maintenance resin particles having a specific average particle diameter) are used as a gloss removing agent. It was found that by adding to the black film, the film can be reduced in glossiness and anti-fingerprint.

Further, it has been found that not only organic resin particles but also inorganic fine particles such as silica and solid lubricants such as fluorine resins can be polished as gloss scavengers, thereby reducing glossiness without significantly impairing blackness and improving fingerprint resistance.

In addition, in particular, when wet silica was mixed as inorganic fine particles and fluorine compound particles as a solid lubricant, it was found that these blending components further increased the gloss elimination effect and the fingerprint resistance, and particularly, an excellent toughened black steel sheet could be obtained.

The organic resin particles used in the present invention include urethane resin particles, silicone resin particles, and epoxy resin particles. Particles such as amino resin particles, acrylic resin particles, acrylonitrile resin particles, acryl-urethane resin particles, polyamide resin particles, polyester resin particles, and polyfluoropropylene resin particles.

These organic resin particles may be transparent (white as powder), but those obtained by blackening the organic resin particles with a black pigment such as carbon black or those dyed with the black resin with a black dye are used. By doing so, the gloss can be reduced without impairing the blackness of the black coating.

As the urethane resin particles, there are particles such as BURNOCK CFB 100 (transparent) and Bernok CFB 600C (black) manufactured by Dainippon Ink & Chemicals Co., Ltd., and Toshiba Silicone Co., Ltd. TOSPEARL There are particles such as 103, 105, 108, 120, 130, 145, 3120, 240 (greater white) and the like.

As amino resin particles, Nihon Shokubai Zefomm EPOSTAR S, S6, S12, L15, MS, M30 (more than white), which is a condensation product of benzoguanamine or melamine and formaldehyde, EPOCOLOR BP1002 , 1004, 1008, 1015 (more than black) and the like.

As acrylic resin particles, Sogaku Chemical Co., Ltd. MR-7G, MR-13G, MR-20G, Toyo Boseki Co., Ltd.Taftic AR-650S (transparent), AR-650S-C (black), ( Note) There are particles such as Nihon Shokubai CX0504 (black).

As acrylonitrile resin particles, there are particles such as Teftic AM manufactured by Toyo Boseki Co., Ltd. and Taftic A20, and particles such as EPOSOFT EBS102 manufactured by Nippon Shokubai Co., Ltd. as acryl urethane resin particles.

Examples of the polyamide resin particles include particles such as ATOCHEM S.A. orgasol 2002 (nylon 12) UL-D, EX-D, orgasol 1002 (nylon 6) D, and the like.

The blending amount of the organic resin particles is 1 to 150 parts by weight, preferably 10 to 100 parts by weight based on 100 parts by weight of the gas resin. If the blending amount of the organic resin particles is less than 1 part by weight, the gloss removal effect is insufficient. On the other hand, if the amount of the organic resin particles is more than 150 parts by weight, the viscosity of the black resin composition is increased. The film cannot be formed.

The organic resin particles are preferably those having an average particle diameter of 0.1 to 30 µm. If the average particle diameter of the organic resin particles is less than 0.1㎛, the gloss removal effect is less. On the other hand, if the average particle diameter exceeds 30㎛, the film thickness of the black film is thinner than 5㎛, so that most of the organic resin particles are exposed in the film. As a result, the resin particles easily come off from the surface of the coating, the scratch resistance is poor, and the spot weldability is also reduced.

And, the average particle diameter of the preferred resin resin particles is 1 to 25 mu m. If the average particle diameter of the organic resin particles is less than 1 µm, the anti-fingerprint improving effect is small. Moreover, in order to improve anti-fingerprint further, it is preferable to set it as 2 micrometers or more of average particle diameters, More preferably, it is 4 micrometers or more.

On the other hand, when the average particle diameter exceeds 25 µm, the hiding power of the film is reduced by the organic resin particles, and the film is whitened, which impairs blackness. From this viewpoint of blackness, it is preferable that average particle diameter is 15 micrometers or less, More preferably, it is 10 micrometers or less. 1 shows the relationship between the average particle diameter of the organic resin particles and the fingerprint properties of the black film.

In the black steel sheet of the present invention, a solid lubricant is preferably added to the black film for the purpose of removing the gloss of the black film and improving the lubricity.

Solid lubricants used in the present invention include the following.

Hydrocarbon compounds: Polyolefin wax, paraffin wax

Fluorine resin compound: For example, polytetrafluoroethylene resin, polyvinyl fluoride resin, polytetrafluoroethylene resin, polyvinylidene fluoride resin, etc.

Fatty acid amide compounds: for example, stearic acid amide, palmitic acid amide, methylene vesstearoamide, ethylenebis stearamide, oleic acid amide, ethyl acid amide, alkylene bis fatty acid amide, and the like.

Metal soaps: for example, calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc.

Polydisdene Disulfide

Others: graphite, graphite fluoride, boron nitride, polyalkylene glycol, grease, alkali metal sulfate

The polyethylene wax used for this invention includes SANWAX 151P, 171P, 165P, etc. by Sanyo Kasei Koyogyo Co., Ltd.

Moreover, as paraffin wax, HNP-11 by Nippon Shiro Co., Ltd. etc. are mentioned. Polytetrafluoroethylene (PTFE) resins include HOSTAFLON TE 9205, manufactured by Hoechst, SST-1MG, manufactured by Shamock, Rubron L-5, manufactured by Daikin Kogyo Co., Ltd., and the like. Fluorine resin (PTFE etc.) is the most preferable from a viewpoint of gloss elimination effect and anti-fingerprint improvement.

The compounding quantity of a solid lubricant is 1-100 weight part with respect to 100 weight part of gas resins, Preferably it is 10-60 weight part. If the solid lubricant compounding amount is less than 1 part by weight, the gloss elimination effect is insufficient. On the other hand, if it exceeds 100 parts by weight, the viscosity of the black resin composition is increased, the coating workability is lowered, and at the same time, the blackness of the black film is lowered to damage the tube.

In addition, the black steel sheet of the present invention can add inorganic fine particles for the purpose of removing the gloss of the black film. As the inorganic pigment used in the present invention, silica having both a gloss elimination effect and a rust preventing effect is most preferred.

In addition, poorly soluble chromate, sieving pigments (for example, diatomaceous earth, calcium carbonate, talc, mica, etc.), carbon black and the like can be used. The poorly soluble chromate has a small gloss elimination effect, but has a large anticorrosive effect. Therefore, it is preferable to add the poorly soluble chromate, and a greater effect can be obtained by use with silica.

Silica used in the present invention is a dry silica (for example, AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL 380, AEROSIL R 811, AEROSIL R 972, AEROSIL R 805, AEROSIL R 974, etc. manufactured by Nippon Aerosol Co., Ltd.). ), Colloidal silica (for example, MA-ST, IPA-ST, IBA-ST, EG-ST, XBA-ST, ETC-ST, DMAC-ST, etc., manufactured by Nissan Chemical Industries, Ltd.), wet silica, Sedimentation method (heating, T-32 (S), K-41, F-80 made by Tokuyama Soda Co., Ltd.), wet silica gel method (for example, thyroid made by Fuji Debson Kagaku Co., Ltd.) SYLOID) 244, Cyroid 150, Cyroid 72, Cyroid 65, SHIELDEX, etc.) can be used. Moreover, it is also possible to mix and use two or more types of said silicas.

The poorly soluble chromate includes barium chromium (BaCrO ₄ ), strontium chromium (SrCrO ₄ ), lead chromate (PbCrO ₄ ), zinc chromate (ZnCrO ₄ · 4Zn (OH) ₂ ), calcium chromium (C ₂ CrO ₄ ), Potassium chromate (K ₂ O. 4ZnO. 4CrO _3. 3H ₂ O) and silver chromic acid (AgCrO ₄ ).

The compounding quantity of an inorganic fine particle is 1-100 weight part with respect to 100 weight part of gas resins, Preferably it is 10-60 weight part. If the amount of the inorganic fine particles is less than 1 part by weight, the gloss elimination effect is insufficient, and in the case of silica, the antirust effect is not sufficiently obtained. On the other hand, if the content exceeds 100 parts by weight, the viscosity of the black resin composition is increased, the coating workability is lowered, and the blackness of the black film is remarkably lowered, thereby deteriorating the appearance.

When one or more of the above-mentioned inorganic fine particles and solid lubricants are added together with the resin resin particles in the black coating, the gloss of the coating can be effectively reduced without significantly reducing the blackness, and also the corrosion resistance and lubricity (press workability) are remarkably decreased. It becomes possible to improve.

In addition, the black steel sheet of the present invention is further characterized by blending one or more types of wet silica and fluorine compound particles, in particular both wet silica and fluorine compound particles, in addition to organic resin particles having an average particle diameter of 1 to 25 µm in the black film. The glossiness can be reduced and compared with the case where these are not blended at all. That is, by adding the organic resin particles and the wet silica or / and fluorine compound particles in combination, a weldable gloss-clear black coating excellent in blackness and fingerprint resistance can be obtained.

The reason why these components contribute greatly to anti-fingerprint improvement is as follows.

In other words, the present invention disperses the organic resin particles in the black coating composition, the paint flow shrinkage along the particles, irregularities are formed on the surface of the black coating, the surface becomes rough. In this case, as described above, excellent anti-fingerprint is obtained when the average particle diameter of the organic resin particles is 1 µm or more, preferably 2 µm or more (more preferably 4 µm or more). In the case where the organic resin particles have such a particle size, even if a finger contacts the film, the pure resin contacts only the convex portions of the film surface uneven by the organic resin particles, and thus the contact area of the finger is smaller than that of the film having a smooth contact area. Therefore, the fingerprint is hardly noticeable because the fingerprint is difficult to be photographed and the degree of reflection and scattering of light at the portion where the fingerprint is attached is almost the same as the degree of reflection and scattering of light at the portion where the fingerprint is not attached. It is thought to be due to two effects.

On the other hand, when the average particle diameter of the organic resin particles becomes larger, there is a problem that the blackness of the thin black film (˜5 μm) decreases and the color becomes 0101. Therefore, as described above, the average particle diameter of the organic resin particles is 25 μm or less. Preferably, the thickness should be 15 µm or less (more preferably 10 µm or less). However, even when the organic resin particles having a specific particle size in such a specific range are blended, the surface of the black film is free of convexities and particles by the particles. As a result, a flat recessed portion is formed, and as a result, microscopic nonuniformity occurs in the film thickness, and blackness is impaired.

In addition, when wet silica or / and fluorine compound particles are mixed with the oil and fat resin particles, fine roughness is also given to the smooth recesses of the coating between the organic resin particles, and the roughness not only reduces the glossiness. Since the anti-fingerprint can be improved and the roughness can be uniformly imparted, a film with less microscopic stains can be formed as compared with the case where the organic resin particles are added alone. It is thought that a film is obtained.

As said wet silica, what was manufactured by the sedimentation method (for example, Tokuyama Soda Co., Ltd. T-32 (S), K-41, F-80, Mizuzawa Kagaku Kogyo Co., Ltd.) Manufacture Mizukasil P-510, Mizugasil P-527, Mizukasil P-802, etc., manufactured by gel method (Fuji Debson Kagaku Co., Ltd. manufacture thyroid 244, thyroid 150, thyroid 404, Sai) Lloyd 620, Mizuzaga Kagoku Kogyo Co., Ltd. Mizukasil P-78, Mizukasil P-707, etc. can be used. Moreover, you may mix and use 2 or more types of said silicas.

The compounding quantity of wet silica is 1-30 weight part with respect to 100 weight part of gas resins, Preferably it is 58-20 weight part. If the blending amount of wet silica is less than 1 part by weight, the anti-fingerprint improving effect is small. On the other hand, even if the blending amount exceeds 30 parts by weight, an effect corresponding to the blending amount cannot be obtained.

The fluorine compound particles include polytetrafluoroethylene particles (eg, Hoechst Corporation Hostaflon TF 9205, Hostaflon TF 9202, Shamrock Corporation SST-1MG, SST-2, SST-3, etc., Daikin Kogyo Co., Ltd.). Manufacture Lubron L-2, Lublon L-5, etc., Mitsui Dupont Fluoro Chemical Co., Ltd. make MP 1200, MP 1300, etc., Tetrafluoroethylene-ethylene copolymer particle (made by Daikin Kogyo Co., Ltd. make) EP-610 etc.), tetrafluoroethylene- perfluoroalkyl vinyl ether copolymer particle | grains (Mitsui Dupont Fluoro Chemical Co., Ltd. Teflon 34aJ etc.), etc. are mentioned.

The compounding quantity of the fluorine compound particles is 1 to 40 parts by weight, preferably 10 to 30 parts by weight based on 100 parts by weight of the gas resin. If the blending amount of the fluorine compound particles is less than 1 part by weight, the anti-fingerprint improving effect is small. On the other hand, even if the blending amount exceeds 40 parts by weight, the effect corresponding to the blending amount is not obtained.

In addition, when the wet silica and the fluorine compound particles are added in combination, good anti-fingerprint can be obtained without particularly impairing blackness.

The gloss-clear black coating containing the organic resin particles, wet silica, and fluorine compound particles having an average particle diameter of 1 to 25 µm as described above is sufficiently provided with the necessary properties as it is, but further provides good self-lubricating activity during press working. In order to further improve the corrosion resistance of the above-mentioned polyethylene wax and paraffin wax as a solid lubricant, and to further improve the corrosion resistance of the processed part such as after press working, the above-mentioned poorly soluble chromate and dry silica One or more kinds can be added.

The compounding quantity of polyethylene wax and paraffin wax added as a solid lubricant is 1-40 weight part in total with respect to 100 weight part of gas resins, Preferably it is 10-30 weight part. If the blending amount thereof is less than 1 part by weight, the effect of improving the lubricity is less. On the other hand, if the blending amount exceeds 40 parts by weight, the blackness of the black film is affected. Polyethylene wax and paraffin wax may also be added in combination.

The compounding quantity of the poorly soluble chromate and dry silica added as a rust preventive pigment is 1-40 weight part in total with respect to 100 weight part of gas resins, Preferably it is 10-30 weight part. If the amount of these rust preventive pigments is less than 1 part by weight, the effect of improving the rust prevention effect is insufficient. On the other hand, even if it is blended in excess of 40 parts by weight, the effect of improving the corrosion resistance corresponding to the amount of the compound cannot be expected. It is not suitable because it is crazy. These antirust pigments may be added in combination of two or more kinds.

In the steel sheet of the present invention, other black pigments (inorganic pigments, organic pigments) or black dyes may be added to the black film in order to adjust black subtle color to taste.

In addition, by adding carbon black, the inorganic fine particles, not only the glossiness can be adjusted but also the blackness can be changed. In addition, by adding coloring pigments and coloring dyes other than black, subtle color tones such as a red atmosphere and a blue atmosphere can be adjusted even in the same black color.

The above black film is diluted with a solvent, if necessary, and the composition is applied to a predetermined film thickness by a method such as roll squeezing, a roll coater or an air knife, and then a plate temperature of 80 to 300 ° C. (preferably Is obtained by heat curing at 120 to 250 ° C.

The coating method and the baking method are performed by a general method, and there is no particular limitation, but in the manufacture of the steel sheet of the present invention, there is a great advantage that the coating equipment for manufacturing the high corrosion resistant surface treated steel sheet owned by the steel manufacturer is used as it is.

According to the present invention described above, since the black coating is a thin film (5 탆 or less) than the conventional coated steel sheet, welding is possible, and further, a black steel sheet having low gloss, excellent blackness, and hardly noticeable fingerprints is obtained.

In addition to the above characteristics, this black steel sheet is excellent in adhesion, workability, corrosion resistance, and light fastness of the black film, and can be manufactured by coating and baking by a conventional roll coater. There is no problem of deterioration in bathing due to elution of the plating, and therefore, productivity can be greatly improved, and a black steel sheet excellent in both performance and productivity can be provided.

Moreover, the black steel sheet in which the black film contains the organic solvent soluble black azo metal complex salt dye as a black dye shows especially excellent light fastness. Moreover, among the black azo metal complex dyes, the steel sheet of the black coating containing the black azo chromium complex dyes exhibits particularly excellent corrosion resistance with excellent light fastness.

In addition, the black steel sheet containing the organic solvent-soluble black azo dyes or the black azine dyes in the black film has a slightly lower light fastness than the organic solvent-soluble black azo metal complex dyes, and also exhibits indoors such as home appliances. In addition, there is no problem at all, and since the addition of these black dyes is about 5-8% of the organic solvent-soluble black azo-based metal complex dyes, there is an advantage that the raw material cross of the black coating composition is low.

In addition, particularly excellent gloss removal effect and fingerprint resistance can be obtained by complex addition of organic resin particles and wet silica or / and fluorine compound particles having a specific particle size in the black film.

Next, the black steel sheet of this invention which has a two-layer film which consists of a chromate film and a black film on one side of a steel plate, and has only a chromate film on the other side is demonstrated.

The structure of the two-layer coating side of this steel sheet is the same as that of the black steel sheet mentioned above. Therefore, the chromate coating of the chromate single-layer coating side is demonstrated here. The chromate coating may be the same as or different from the chromate coating on the two-layer coating side.

That is, the combination of the chromate coating on the chromate single-layer coating side and the two-layer coating side can be, for example, a reactive chromate coating or an electrolytic chromate coating or a coated chromate coating having the same composition on both sides. In addition, when the steel sheet of the present invention is used as it is without coating, the black film on the single-layer coating side can be used as a high-performance coating type chromate, and in this case, the chromate film on the two-layer coating side can be any coating type chromate coating. On the other hand, the chromate coating on the single-layer coating side can be a chromate coating having a specific composition containing, for example, silica or an aqueous resin.

These chromate coatings are the same as those described above for the chromate coating of the two-layer coating, but in particular, when a coated chromate is used on the chromate single-layer coating side, a chromate treatment liquid having any one of the following compositions (1) to (4) is used. It is preferable.

(1) Chromate treatment liquid containing hexavalent Cr ions and trivalent Cr ions, hexavalent Cr ions / 3 valent Cr ions = 40/60 to 80/20 by weight ratio

(2) Hexavalent Cr ions, trivalent Cr ions and silica sol, containing hexavalent Cr ions / 3 valent Cr ions = 40/60 to 80/20, silica sol / total Cr amount = 1/2 ~ 8/1 chromate treatment liquid

(3) Hexavalent Cr ions, trivalent Cr ions and water-based resins, hexavalent Cr ions / 3 valent Cr ions by weight ratio = 40/60 to 80/20, aqueous resin / total Cr amount = 1/20 to 40/1 chromate treatment solution

(4) Hexavalent Cr ions, trivalent Cr ions, silica sol and water-based resin, containing by weight ratio hexavalent Cr ions / 3 valent Cr ions = 40/60 to 80/20, silica sol / total Cr amount = 1 / 2 ~ 8/1, Aqueous resin / All Cr amount = 1/20 ~ 40/1 Chromate treatment liquid (above, hexavalent Cr ion, trivalent Cr ion, all Cr is converted to metal chromium)

The reason for limitation of the chromate treatment liquids described above will first be explained. First, the weight ratio of hexavalent Cr ions to trivalent Cr ions (hexavalent Cr ions / 3 valent Cr ions) affects the corrosion resistance and chromium fixability. It is preferable to set it as / 60-80 / 20. That is, when hexavalent Cr ions / 3 valent Cr ions exceed 80/20, hexavalent Cr ions which are easily soluble in water are dried in the chromate film even when the plated steel sheet coated with the chromate treatment is dried at a drying temperature of 70 to 250 ° C. Since a large amount exists, the chromium fixation rate after alkali degreasing falls.

On the other hand, when hexavalent Cr ions / 3 valent Cr ions are less than 40/60, the chromium fixation rate after alkali degreasing is improved, but the corrosion resistance is lowered because the amount of hexavalent Cr ions in the chromate film is small. When the coated steel sheet is dried at a drying temperature of 70 to 250 ° C, the hydrophilicity of the chromate film is increased, and thus the fingerprinting property is lowered. In addition, hydrophilicity means the property which is easy to combine with water. Therefore, it is preferable to set hexavalent Cr ion / 3 valent Cr ion to 40/60/80/20.

The reason why the hydrophilicity of the chromate film is increased when hexavalent Cr ions / 3 is less than 40/60 Cr, that is, when the ratio of hexavalent Cr ions is small, is not necessarily clear, but it is assumed that the following reasons.

That is, when hexavalent Cr ions combine with silanol groups, which are hydrophilic groups in silica particles, the chromate film decreases hydrophilicity, but when the ratio of hexavalent Cr ions is small, silanol groups that do not bond with hexavalent Cr are increased. It is thought that the hydrophilicity of a chromate film becomes high.

In order to further improve the poor solubility, corrosion resistance and fingerprint resistance of the chromate coating, it is preferable to set the hexavalent Cr ions / 3 valent Cr ions to 50/50 to 75/25.

Aqueous solutions containing hexavalent Cr and trivalent Cr ions may be prepared by reducing a portion of the hexavalent Cr ions in an aqueous solution of chromic anhydride (CrO ₃ ) by reducing agents such as sugar, glycol, starch, methanol, ethanol, or oxalic acid. It can obtain by reducing with Cr ion.

Next, when silica sol (SiO ₂ ) is added to the chromate treatment liquid, corrosion resistance is further improved and anti-fingerprint is also improved. However, when the weight ratio (silica sol / total Cr amount) of the silica sol and the total Cr amount is less than 1/2, no significant improvement in corrosion resistance and fingerprint resistance is recognized. On the other hand, when silica sol / Cr exceeds 8/1, the chromate film becomes more hydrophilic and thus the fingerprinting property is lowered. When the finger touches the steel sheet, sweat easily adheres to the chromate film, and fingerprints remain clearly. Moreover, since the electrical resistance of a chromate film increases, weldability also falls. Therefore, the amount of silica sol / total Cr is preferably 1/2 to 8/1. In addition, in order to further improve the corrosion resistance and fingerprint resistance of the chromate film, it is preferable that the amount of silica sol / total Cr is / 1 to 7/1.

Silica sol has a good dispersibility in the chromate treatment liquid as compared to the dry silica powder, and therefore is difficult to aggregate. For this reason, the use of the chromate treatment solution to which silica sol was added improves the corrosion resistance and fingerprint resistance of a chromate film compared with the case to which the chromate treatment solution to which dry silica powder was added is used. Silica sol is prepared by ion exchange method, electrodialysis method or the like using water glass (aqueous solution of sodium silicate) as a raw material. As a silica sol, Nissan Chemical Industries, Ltd. Snowtex O, Snowtex OL, etc. can be used, for example.

In addition, when water-dispersible resin particles (hereinafter referred to as aqueous resins) are added to the chromate treatment liquid, anti-fingerprint properties are improved, and at the same time, the upper resistance of the steel sheet and press forming can be improved.

As the aqueous resin used in the present invention, it is necessary to be stably dispersed in the chromate treatment liquid, and for example, resins such as polyester, acrylic, alkyd, vinyl, silicone and latex may be used.

The weight ratio (aqueous resin / total Cr amount) between the aqueous resin and the total amount of Cr is preferably set to 1/20 to 40/1. If it is less than 1/20, the effect of improving fingerprint resistance, scratch resistance, and press formability is not sufficiently expected. On the other hand, even if an aqueous resin is added in excess of 40/1, the effect corresponding to the addition amount is not obtained.

In addition, the trivalent PO ₄ ions and the divalent Zn ions have an effect of improving the poor solubility of the chromate film. Therefore, the trivalent PO ₄ ions and the divalent Zn ions are optionally added to the chromate treatment liquid having the above-described composition. It can be added in the following ratio.

Weight ratio between trivalent PO ₄ ions and total Cr content

(Trivalent PO ₄ ion / Total Cr): 1/30 ~ 2/1

Weight ratio between divalent Zn and hexavalent Cr ions

(Divalent Zn ion / Hexavalent Cr ion): 1/40 ~ 2/3)

If the amount of trivalent PO ₄ ions / total Cr is less than 1/30, no significant improvement in the poor solubility of the chromate film is recognized. On the other hand, when the amount of trivalent PO ₄ ions / total Cr exceeds 2/1, the pH value of the chromate treatment liquid is lowered, so that the etching property is increased, and therefore, the chromate treatment liquid is aging faster, and the fingerprinting property is also lowered. Therefore, the amount of trivalent PO ₄ ions / total Cr needs to be 1/30 to 2/1.

Further, when the divalent Zn ion / hexavalent Cr ion was less than 1/40, no significant improvement in the poor solubility of the chromate film was recognized. On the other hand, when the divalent Zn ion / hexavalent Cr ion exceeds 2/3, a precipitate is formed in the chromate treatment liquid. Therefore, divalent Zn ion / hexavalent Cr ion needs to be 1 / 40-2 / 3.

The chromate treatment solution described above is prepared at an appropriate concentration, and applied by a method such as roll squeezing or roll coater, and then dried by heating in a range of 70 to 300 ° C. If the drying temperature is less than 70 ° C, no significant improvement in the fixed rate of the chromate coating is recognized. On the other hand, even at a drying temperature exceeding 300 ° C, a higher effect on the fixation rate of the chromate coating cannot be expected, and conversely, since the cracks occur on the chromate coating, corrosion resistance is lowered.

The chromate coating amount on the chromate monolayer coating side described above is in the range of 10 to 120 mg / m 2 (metal chromium conversion). If the adhesion amount of the chromate film is less than 10 mg / m 2, no particular improvement in corrosion resistance is recognized. On the other hand, when the adhesion amount exceeds 120 mg / m 2, the chromium fixation rate after alkali degreasing cannot be improved. For this reason, the chromate coating amount needs to be 10-120 mg / m <2>.

The single-sided black steel sheet of the present invention described above has a particularly excellent weldability because the black coating is thinner (5 µm or less) than the conventional coated steel sheet, and the black coating is formed only on one surface. Furthermore, it has a low glossiness and is excellent in blackness, fingerprints are hardly noticeable, and also excellent in adhesion, processability, corrosion resistance and light fastness of a black film. In addition, since it can be manufactured by coating and baking by reference roll coater, etc., there is no problem of deterioration of bath due to elution of plating compared to black steel sheet of reaction etching type, and thus productivity can be greatly improved. It is possible to provide an excellent black steel sheet in terms of both performance and productivity.

Moreover, the single-sided black steel plate which formed the coating type chromate film of a specific composition on the black film non-formation surface is especially excellent in a fingerprint-proof property and corrosion resistance, and it is a very useful material etc. with the said outstanding weldability.

EXAMPLES I

As steel sheets corresponding to home appliances and office equipment, black steel sheets according to the present invention and black steel sheets of comparative examples were manufactured.

Each black steel sheet is washed with water and dried after alkali degreasing of the zinc-based galvanized steel sheet, and the coated chromate treatment liquid is coated with a roll coater or immersed in an electrolytic chromate treatment bath to form a chromate coating. As a layer, the resin liquid was applied to both sides of the steel sheet by a roll coater. Again, it was air-cooled by drying after heating.

Each condition of the said coating type chromate treatment and electrolytic chromate treatment is as follows.

Coating type chromate treatment condition

Trivalent Cr ion: Hexavalent Cr ion = 2: 3, pH = 2.5 (pH adjusted to KOH), a solid solution 20g / L chromate treatment solution was applied by a roll coater at room temperature and dried.

Electrolytic Chromate Treatment Condition

A cathode electrolytic treatment was performed with a current density of 4.9 A / dm ² and an electrolysis time of 20 seconds in a bath of CrO ₃ : 50 g / l, H ₂ SO ₄ : 0.5 g / l, and bath temperature of 50 ° C., followed by washing with water and drying.

In Tables 1 to 3, the plating discs used in Examples 1 to 7, the gas resins for forming the black film, and the black imparting agent are shown.

In Tables 4 to 6, various additives used in Examples 1 to 3 are shown. In Table 19-23, the various additives used in Examples 4-7 were shown.

7 to 18 and Tables 24 to 41 show the test results for the plated steel sheet, chromate coating, composition for forming a black film, and the obtained black steel sheet used in the examples and comparative examples.

The composition shown in Tables 2 to 6 and 19 to 23 is blended according to the compounding amounts shown in Tables 7 to 18 and 24 to 41, and a solvent is added as necessary. Diluted.

In addition, the test of the black steel plate created by the above was performed as follows.

(1) blackness

The L value of the black film was measured using the multi-light spectrophotometer (type MSC) by the Suga Test Machine Co., Ltd. product. The evaluation criteria are as follows.

◎: L 15

○ +: 15L 20

○: 20 L 25

○ －: 25L 30

×: L30

(2) glossiness

The glossiness of the incidence angle and the reflectivity 60 degrees was measured using the gloss meter made by Suga Tester Co., Ltd. The higher the glossiness, the higher the gloss.

(3) weldability test

Spot welding was performed on condition of the following, and it evaluated by continuous RBI. In addition, evaluation criteria are as follows.

Electrode: Cr-Cu, D type

Diameter of the electrode: 6mmψ

Welding current: 10kA

Energizing force: 200kg

Power supply time: 12 cycles / 60 Hz

◎: 500 RBI or more

○: 100 RBI or more

×: less than 100 RBI

(4) Corrosion resistance test of plate part and processing part

The salt spray test (JIS-Z-2371) of the flat plate part and the erikxen 7 mm extruded part was carried out for 240 hours. Corrosion resistance was evaluated by the time until the incidence of white rust reached 5%. The evaluation criteria are as follows.

◎: No white rust

○ +: over 120 hours, within 240 hours

○: over 48 hours, within 120 hours

○ －: More than 24 hours, less than 48 hours

×: within 24 hours

(5) adhesion of black film

100 checkerboard scales were engraved on the black coating surface at 1 mm intervals, and adhesiveness was evaluated by sticking and peeling the adhesive tape to this bottom scale. The evaluation criteria are as follows.

◎: 0% peeling area

○: less than 10% of the peeling area

△: peeling area 10% or more, less than 20%

X: 20% or more of peeling area

(6) Machinability Test

Hat-draw processing by 5 mm extrusion was performed at a blank diameter of φ90 mm and a die diameter of φ50 mm, and the side processing portion of the steel sheet was peeled off with adhesive tape, and the degree of peeling of the coating film to the tape and the change in appearance of the black coating were evaluated. . The evaluation criteria are as follows.

(Double-circle): There is no powdery phase peeling at all.

○ +: Some powdery peeling occurs locally but the appearance of black film hardly changes.

(Circle): The tape turns black very lightly by separation of powder, but the appearance of a black film hardly changes.

(Circle): A tape turns light black by powder separation, and the appearance of a black film becomes white a little.

(Triangle | delta): The tape turns black by powder separation, and the whitening of a black film is outstanding.

X: The tape becomes remarkably black by powder separation, and the black film is completely peeled off.

(7) light fastness

The black film was irradiated with a fade meter by JIS L-0842 2nd exposure method, and the grade was judged on the blue scale.

◎: Blue scale 7 ~ 8 class

○: Blue scale 5 ~ 6

△: Blue Scale Level 3 ~ 4

×: Blue Scale Class 1 ~ 2

(8) anti-fingerprint

The actual fingerprint was taken on the surface of the black film, and the degree to which the fingerprint was noticeable was visually evaluated. The evaluation criteria are as follows.

◎: Not noticeable at all.

(Circle) +: It is hardly noticeable.

○: somewhat noticeable.

×: stands out.

Example 1

The effects of the types of black impregnating agents, their blending amounts, the types of oil-bearing particles and the blending amount of the black coatings on black coating, glossiness, weldability, processability, adhesion, corrosion resistance, fingerprint resistance and light fastness were investigated. . The results are shown in Tables 7-12. Comparative Example (1) From the comparison with No. 8, it can be seen that the gloss is decreased by the addition of the organic resin particles and the anti-fingerprint is improved.

Example 2

The effects of the solid lubricant blended in the black coating, the inorganic fine particles, and the blending amount on the hump characteristics were investigated. The results are shown in Tables 12-16. These results show that the fingerprint resistance is improved when the inorganic fine particles and the solid lubricant are added in combination than the organic resin particles alone.

Example 3

The influence of the type of the plated steel sheet, the type of gas resin, the type of chromate treatment and its adhesion amount, and the baking temperature on the above characteristics was investigated. The results are shown in Table 17 and Table 18.

Example 4-Example 7

In particular, the black coating is an embodiment of the black steel sheet of the present invention in which the specific average particle diameter contains organic resin particles, wet silica, and / or fluorine compound particles, and the type and amount of each additive added to the black coating are given to the above characteristics. The impact was investigated. The results are shown in Tables 24-41.

In addition, * 1 to * 24 shown in the table indicated the following contents.

* 1: No. of plated steel sheet shown in Table 1.

* 2: No. of gas resins listed in Table 2.

* 3: No. of the additive (black imparting agent) shown in Table 3.

* 4: The weight part of an additive with respect to 100 weight part of gas resins is shown.

* 5: No. of the additive of Table 4

* 6: The weight part of an additive with respect to 100 weight part of gas resins is shown.

* 7: No. of the additive of Table 5

* 8: The weight part of an additive is shown with respect to 100 weight part of gas resins.

* 9: No. of the additive of Table 6

* 10: The weight part of an additive is shown with respect to 100 weight part of gas resins.

* 11: No. of plated steel sheet shown in Table 1.

* 12: No. of gas resins listed in Table 2.

* 13: No. of the additive (black imparting agent) shown in Table 3.

* 14: The weight part of an additive is shown with respect to 100 weight part of gas resins.

* 15: No. of the additives of Table 19.

* 16: The weight part of an additive with respect to 100 weight part of gas resins is shown.

* 17: No. of the additives of Table 20.

* 18: The weight part of an additive is shown with respect to 100 weight part of gas resins.

* 19: No. of the additives of Table 21.

* 20: The weight part of an additive with respect to 100 weight part of gas resins is shown.

* 21: No. of the additive of Claim 22

* 22: The weight part of an additive is shown with respect to 100 weight part of gas resins.

* 23: No. of the additives of Table 23.

* 24: The weight part of an additive is shown with respect to 100 weight part of gas resins.

EXAMPLES II

As a steel sheet mainly for home appliances and office equipment, a single-sided black steel sheet according to the present invention and a single-sided black steel sheet of a comparative example were manufactured.

Each single-side black steel sheet is alkali-degreased on the surface of the galvanized steel sheet or zinc-based alloy plated steel sheet, washed with water and dried, and a two-layer film composed of a chromate film and a black film on one side by one of the following steps (1) to (3). A chromate monolayer film was formed in the film.

The used plating disc, gas resin, black imparting agent and various additives are the same as EXAMPLES I.

① (plated steel sheet) → reactive chromate treatment (both sides) → washing → drying → black coating (single side) → heating element

② (Plated steel sheet) → Electrolytic chromate treatment (both sides) → Water washing → Drying → Black coating (single side) → Heating element

③ (Plated steel sheet) → Coating type chromate treatment (both sides) → Coating type chromate treatment (opposite surface) → Drying → Black coating (single side) → Heating element

Example 1

After a reactive chromate treatment, an electrolytic chromate treatment or a coated chromate treatment was performed on both surfaces of the plated steel sheet, a black coating was applied onto the chromate coating on only one surface of the steel sheet, followed by heat curing. The spot weldability test was done about each obtained single-sided black steel plate. The test results are shown in Table 42 and Table 43. In addition, the chromate processing conditions in a present Example are as follows.

Reactive Chromate Treatment Condition

After a bath consisting of CrO ₃ : 10 g / l, H ₂ SO ₄ : 2g / l, trivalent Cr ions: 2g / l, and divalent Zn ions: 3g / l at 50 ° C. and spraying for 5 seconds, Washed and dried. Management of chromium adhesion amount was performed by forming free oxygen of a bath.

Electrolytic Chromate Treatment Condition

The cathode was treated with CrO ₃ : 50 g / l, H ₂ SO ₄ : 0.5 g / l, and the bath at 50 ° C. with a current density of 4.9 A / dm ² and an electrolysis time of 20 seconds, followed by water washing and drying.

Coating type chromate treatment condition

After apply | coating the chromate treatment liquid which consists of the following composition with a roll coater, it dried immediately at pan temperature and 100 degreeC, without washing with water. In addition, the chromate adhesion amount was adjusted according to chromate treatment liquid concentration (solid content) and a roll coater condition.

Hexavalent Cr ions / 3 valent Cr ions = 70/30

SiO ₂ / Total Cr = 4/1

Trivalent PO ₄ Ion / I Cr = 0

Divalent Zn ion / Hexavalent Cr ion = 0

In the weldability test, spot welding was performed on two single-sided black steel sheets in which the double-layered coating surface and the chromate single-layer coating surface were overlapped under the following conditions, and evaluated using a continuous score. In addition, evaluation criteria are as follows.

Electrode: Cr-Cu, DR

Diameter of the electrode: 6mmψ

Welding current: 10kA

Energizing force: 200kg

Power supply time: 12 cycles / 60 Hz

◎: 700 RBI or more

○: 200 RBI or more

×: less than 200 RBI

In addition, * 1-* 24 shown in the table | surface represent the same content as EXAMPLES I.

Example 2

On one side of the plated steel sheet, a two-layer coating consisting of a coated chromate and a chromate coating was formed, and on the other side, a chromate single-layer coating consisting of coated chromate was formed. In this example, the spot weldability test for each single-sided black steel plate and the corrosion resistance, Cr fixation rate, and anti-fingerprint test for each single-sided black steel plate were carried out by changing the composition of the chromate treatment liquid for forming the chromate single-layer coating. It was done. In Table 44 and Table 45, the manufacturing conditions of each single-sided black steel plate were shown, and the result of each test was shown in Table 46 and Table 47.

In addition, manufacturing conditions other than those shown in Table 44 and Table 45 are as follows.

(A) Two-layer coating side (black coating formation side)

Coating type chromate treatment condition

Treatment under the same conditions as in Example 1

Black film

The black film which consists of the following composition was formed in the film thickness of 2.0 micrometers, and baked at the baking temperature of 210 degreeC (pan temperature).

Thermosetting resin (Table 1, No. 1) … 100 parts by weight

Organic solvent soluble black azo metal complex dye (Table 3, No. 1)... … 70 parts by weight

Organic resin particles (Table 4, No. 2)... … 60 parts by weight

(B) Chromate monolayer film side

After apply | coating the chromate treatment liquid which consists of the composition shown to Table 44, Table 45 with the roller coater, it dried immediately at predetermined plate temperature, without washing with water. In addition, the chromate adhesion amount was adjusted according to the chromate treatment liquid concentration (solid part) and the roller coater conditions.

In addition, each said test was done with the following method.

(1) corrosion resistance

A salt spray test (JIS-Z-2371) of a flat plate was conducted on the chromate coal seam coating side. Corrosion resistance was evaluated by the time required for white rust generation to reach 5% by area ratio.

○ +: over 120 hours

○: over 24 hours, within 120 hours

△: more than 4 hours, less than 24 hours

×: within 4 hours

(2) Cr fixation rate

After spraying an aqueous solution for alkali degreasing at 60 ° C. (Nihon Parkarizing Co., Ltd., CL-N364S: 20 g / l) containing sodium silicate as a main component for 1 minute on a chromium monolayer coated surface, The ratio (%) of the chromium deposition amount of was measured, and this was made into the chromium fixation rate.

○ +: 90% or more

○: 70% or more, less than 90%

△: 50% or more, less than 70%

×: less than 50%

(3) anti-fingerprint

The degree to which the fingerprint was pressed by pressing a finger on the surface of the test piece was visually evaluated.

○: fingerprint is not visible

△: fingerprint is more noticeable

×: fingerprint is remarkably noticeable

(4) weldability

Same as Example 1

No.1 ~ 3: Organic solvent soluble thermosetting resin

No.4: Thermoplastic resin of organic solvent soluble

Claims (32)

A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. Weldable, characterized in that it has a black film with a thickness of 0.3 to 5 μm, in which a black dye having a organic solvent soluble black dye: 1 to 200 parts by weight and organic resin particles: 1 to 150 parts by weight is added to the weight part. Low gloss black steel plate. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. Chromate coating film with a film thickness of 0.3 to 5 μm, containing 1 to 200 parts by weight of an organic solvent soluble black dye as a black imparting agent, 1 to 200 parts by weight, organic resin particles: 1 to 150 parts by weight, and inorganic particles: 1 to 100 parts by weight. Weldable low gloss black steel, characterized in that it has a. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. A black film having a film thickness of 0.3 to 5 µm in which a black dye-soluble organic dye, which is a black imparting agent, is 1 to 200 parts by weight, organic resin particles: 1 to 150 parts by weight, and a solid lubricant: 1 to 100 parts by weight, based on parts by weight. Weldable low gloss black steel, characterized in that it has a. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. 1 to 200 parts by weight of an organic solvent soluble black dye as a black imparting agent, 1 to 200 parts by weight, organic resin particles: 1 to 150 parts by weight, inorganic particles: 1 to 100 parts by weight, and 1 to 100 parts by weight of a solid lubricant A weldable low gloss black steel sheet comprising a black film having a film thickness of 0.3 to 5 µm. The weldable low gloss according to claim 2 or 4, wherein the inorganic fine particles in the black film contain one or two or more selected from the group consisting of silica, extender pigment, poorly soluble chromate and carbon black. Black steel plate. The polyolefin wax, paraffin wax, fluororesin compound, fatty acid amide compound, metal soap, molybdenum disulfide, graphite, graphite fluoride, boron nitride and polyalkylene glycol as claimed in claim 3 or 4 as a solid lubricant in the black coating. Weldable low gloss black steel sheet containing one or two or more selected from the group consisting of: The organic resin particles in the black film are urethane resin particles, silicon resin particles, epoxy resin particles, amino resin particles, acrylic resin particles and acrylonitrile resin particles according to claim 1, 2, 3 or 4. Weldable low gloss black steel sheet, characterized in that it contains one or two or more selected from the group consisting of acrylic-urethane resin particles, polyamide resin particles, polyester resin particles and polypropylene resin particles. The organic resin particles in the black film are black urethane resin, black silicon resin particles, black epoxy resin particles, black amino resin particles, black acrylic resin particles, and black as claimed in claim 1, 2, 3 or 4. Welding comprising one or two or more selected from the group consisting of acrylonitrile resin particles, black acryl-urethane resin particles, black polyamide resin particles, black polyester resin particles and black polypropylene resin particles Low gloss black steel as possible. The one or two kinds according to claim 1, 2, 3 or 4, wherein the black dye in the black coating is selected from the group consisting of an organic solvent soluble azo dye and an organic solvent soluble azine dye. Weldable low gloss black steel sheet, characterized in that above. The weldable low gloss black steel sheet according to claim 1, 2, 3, or 4, wherein the black dye in the black coating is an organic solvent-soluble azo metal complex dye. The weldable low gloss black steel sheet according to claim 1, 2, 3, or 4, wherein the black dye in the black coating is a mixture of an organic solvent-soluble azo metal complex dye and a phthalocyanine dye. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. A black film having a film thickness of 0.3 to 5.0 µm in which an organic solvent soluble black dye as a black imparting agent is 1 to 200 parts by weight, and an organic resin particle having an average particle diameter of 1 to 25 µm is mixed. Weldable low gloss black steel sheet characterized by having. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. Membrane containing 1 to 200 parts by weight of an organic solvent soluble black dye as a black imparting agent: 1 to 200 parts by weight, organic resin particles having an average particle diameter of 1 to 25 μm: 10 to 150 parts by weight, and wet silica: 1 to 30 parts by weight. A weldable low gloss black steel sheet having a black coating with a thickness of 0.3 to 5.0 µm. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. Organic solvent-soluble black dye, which is a black imparting agent, in an amount of 1 to 200 parts by weight, organic resin particles having an average particle diameter of 1 to 25 μm, 10 to 150 parts by weight, and fluorine compound particles: 1 to 40 parts by weight. A weldable low gloss black steel sheet, having a black film with a film thickness of 0.3 to 5.0 µm. A chromate film having a chromium deposition amount (in terms of metal chromium) of 1 to 200 mg / m 2 is formed on the surface of the zinc or zinc-based alloy plated steel sheet. Organic solvent-soluble black dye, which is a black imparting agent, based on the weight part, 1 to 200 parts by weight, organic resin particles having an average particle diameter of 1 to 25 μm: 10 to 150 parts by weight, wet silica: 1 to 30 parts by weight, fluorine compound Particles: A weldable low gloss black steel sheet characterized by having a black film with a thickness of 0.3 to 5.0 µm containing 1 to 40 parts by weight. The black coating contains 1-40 weight part in total of 100 weight part of gas resins at least 1 type of poorly soluble chromate and dry silica. Weldable low gloss black steel sheet. The black coating contains 1-40 weight part in total of at least 1 sort (s) of polyethylene wax and paraffin wax with respect to 100 weight part of gas resins, The black film | membrane of Claim 12, 13, 14 or 15 characterized by the above-mentioned. Weldable low gloss black steel sheet. The weldable low gloss black steel sheet according to claim 12, 13, 14, or 15, wherein the black coating contains the following components (A) and (B). (A) 1 to 40 parts by weight of at least one of poorly soluble chromate and dry silica in total with respect to 100 parts by weight of the gas resin. (B) 1 to 40 parts by weight of at least one of polyethylene wax and paraffin wax in total with respect to 100 parts by weight of gas resin The organic resin particles in the black film are urethane resin particles, silicone resin particles, epoxy resin particles, amino resin particles, acrylic resin particles and acrylonitrile according to claim 12, 13, 14 or 15. A weldable low gloss black steel sheet comprising at least one selected from the group consisting of resin particles, acrylic-urethane resin particles, polyamide resin particles, polyester resin particles, and polypropylene resin particles. The organic resin particles in the black film are black urethane resin, particles black silicon resin particles, black epoxy resin particles, black amino resin particles, and black acrylic resin particles according to claim 12, 13, 14 or 15. , Black acrylonitrile resin particles, black acryl-urethane resin particles, black polyamide resin particles, black polyester resin particles, and black polypropylene resin particles. Weldable low gloss black steel sheet. The black dye in the black coating according to claim 12, 13, 14 or 15, wherein one or two organic solvents are selected from the group consisting of azo dyes and organic solvent soluble azine dyes. Weldable low gloss black steel, characterized in that more than one species. The weldable low gloss black steel sheet according to claim 12, 13, 14 and 15, wherein the black dye in the black coating is an organic solvent-soluble azo metal complex dye. The weldable low gloss black steel sheet according to claim 12, 13, 14 or 15, wherein the black dye in the black coating is a mixture of an organic solvent-soluble azo metal complex dye and a phthalocyanine dye. The method according to claim 1, 2, 3, 4, 12, 13, 14, or 15, wherein the black film is formed only on one side of the steel sheet, and the amount of chromium deposited on the other side of the steel sheet. A weldable black steel sheet, characterized in that only a chromate film having a metal chromium equivalent of 10 to 120 mg / m 2 is formed. 25. The weight ratio in terms of metal chromium of a hexavalent Cr ion and a trivalent Cr ion, wherein the chromate film on the steel sheet surface on which only the chromate film is formed contains hexavalent Cr ions and trivalent Cr ions. / 3 trivalent Cr ion) is a chromate coating film obtained by applying a chromate treatment solution having a 40/60 to 80/20, and heating and drying the same. 25. The weight ratio as a metal chromium conversion of the hexavalent Cr ions and the trivalent Cr ions according to claim 24, wherein the chromate film on the steel sheet surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, and silica sol. Chromate with chromium ions / 3 valent Cr ions) of 40/60 to 80/20 and the weight ratio (silica sol / total Cr) of silica sol to total chromium (in terms of metal chromium) is 1/2 to 8/1 It is a chromate film obtained by apply | coating a process liquid and heating and drying this, The weldable black steel plate characterized by the above-mentioned. 25. The weight ratio as a metal chromium conversion of the hexavalent Cr ions and the trivalent Cr ions according to claim 24, wherein the chromate film on the steel sheet surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, and an aqueous resin. Chromate with 40 / 60-80 / 20 of Cr Cr ion / 3 Cr Cr) and 1 / 20-40 / 1 of the weight ratio (aqueous resin / total Cr content) of the aqueous resin and the total amount of chromium (in terms of metal chromium). A weldable black steel sheet, which is a chromate film obtained by applying a treatment liquid and heating and drying the same. 25. The method of claim 24, wherein the chromate film on the steel sheet surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, silica sol, and an aqueous resin, and the metal chromium conversion of the hexavalent Cr ions and trivalent Cr ions is used. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) is 40/60 to 80/20, and the weight ratio (silica sol / total Cr amount) between silica sol and total chromium (metal chromium equivalent) is 1/2 to 8 / 1, a chromate coating obtained by applying a chromate treatment solution having a weight ratio (aqueous resin / total Cr content) of the aqueous resin and the total chromium amount (in terms of metal chromium) of 1/20 to 40/1, and heating and drying it. Weldable black steel sheet characterized by. 25. The steel plate surface of the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, trivalent PO ₄ ions, and divalent Zn ions, and the hexavalent Cr ions and trivalent Cr ions; Weight ratio (hexavalent Cr ions / 3 valent Cr ions) is 40/60 to 80/20, the weight ratio of trivalent PO ₄ ions to all chromium (metal chromium equivalent) (trivalent PO ₄ ions / Total Cr amount is 1/30 ~ 2/1, and the weight ratio (divalent Zn ion / hexavalent Cr ion) of divalent Zn ion and hexavalent Cr ion (in terms of metal chromium) is 1/40 ~ 2/3 It is a chromate coating film obtained by apply | coating the chromate treatment liquid and heating and drying this, The weldable black steel plate characterized by the above-mentioned. 25. The steel sheet surface-side chromate film on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, silica sol, trivalent PO ₄ ions, and divalent Zn ions. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) in terms of metal chromium to Cr ions is 40/60 to 80/20, weight ratio of silica sol to total chromium (metal chromium equivalent) (silica sol / total Cr) ) 1/2 to 8/1, weight ratio (trivalent PO ₄ ion / total Cr amount) between trivalent PO ₄ ions and total chromium amount (in terms of metal chromium) is 1/30 to 2/1, divalent Zn A chromate coating obtained by applying a chromate treatment solution having a weight ratio (divalent Zn ion / hexavalent Cr ion) of 1/40 to 2/3 of ions and hexavalent Cr ions (in terms of metal chromium), and heating and drying them. Weldable black steel sheet, characterized in that. 25. The steel plate surface of the steel plate surface on which only the chromate film is formed contains hexavalent Cr ions, trivalent Cr ions, aqueous resins, trivalent PO ₄ ions, and divalent Zn ions. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) in terms of metal chromium with Cr ions is 40/60 to 80/20, weight ratio between aqueous resin and total chromium (metal chromium equivalent) (aqueous resin / total Cr) ) Is 1/20 to 40/1, the weight ratio (trivalent PO ₄ ion / total Cr amount) between trivalent PO ₄ ions and total chromium amount (in terms of metal chromium) is 1/30 to 2/1, divalent Zn A chromate coating obtained by applying a chromate treatment solution having a weight ratio (divalent Zn ion / hexavalent Cr ion) of 1/40 to 2/3 of ions and hexavalent Cr ions (in terms of metal chromium), and heating and drying them. Weldable black steel sheet, characterized in that. The chromate coating film according to claim 24, wherein the chromate coating film on the steel sheet surface on which only the chromate coating film is formed contains hexavalent Cr ions, trivalent Cr ions, silica sol, aqueous resin, trivalent PO ₄ ions, and divalent Zn ions. Weight ratio (hexavalent Cr ions / 3 valent Cr ions) of 40/60 to 80/20, and the weight ratio of silica sol and total chromium (metal chromium equivalent) to trivalent Cr ions and trivalent Cr ions (silica sol / Total Cr amount) is 1/2 to 8/1, and weight ratio (aqueous resin / total Cr amount) between aqueous resin and total chromium amount (in terms of metal chromium) is 1/20 to 40/1, with trivalent PO ₄ ions Weight ratio (total amount of trivalent PO ₄ ions / total Cr) to total chromium amount (in terms of metal chromium) is 1/30 to 2/1, weight ratio of divalent Zn ion and hexavalent Cr ion (in terms of metal chromium) (2 A weldable black steel sheet comprising a chromate coating film obtained by applying a chromate treatment solution having a valent Zn ion / hexavalent Cr ion) of 1/40 to 2/3, and heating and drying the same.