JPS6157073B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves forming an adhesive layer on an electroplated steel plate with the adhesive held by a nonwoven fabric, and then forming a decorative paint layer thereon and forming a pattern on the surface of the decorative paint layer. The purpose of this method is to provide a method for manufacturing a decorative steel sheet that can easily produce a patterned decorative steel sheet with excellent corrosion resistance and weather resistance. As a means of imparting corrosion resistance to steel materials, surface-coated steel materials have been widely used, and metal-plated and painted steel materials are representative examples thereof. However, recently, steel materials have been used for various purposes and are increasingly being used under harsh conditions, so conventional single plating, such as zinc plating, may not always provide satisfactory results. I can't get it. Therefore, a technology has been developed that improves the appearance and corrosion resistance by painting and coloring the galvanized layer after galvanizing, and this technology has been put into practical use as decorative steel sheets and colored galvanized steel sheets. As is well known. However, the problem with these conventional galvanized/painted surface coatings is that zinc itself becomes a sacrificial anode due to corrosion factors such as moisture and oxygen that pass through the coating, and it easily corrodes and forms corrosion. The problem is that the corrosion under the paint film is likely to progress quickly. On the other hand, with electrolytic lead-plated steel sheets, the lead layer is electrochemically nobler than the base iron, so it is typical of cathodic type galvanized steel sheets. It is different from plated steel plate. For this reason, lead has better corrosion and chemical resistance than zinc, and even if the paint film deteriorates or defects occur, the highly corrosion-resistant lead will protect the base metal for many years. Even if the lead disappears, corrosion will remain in this area and will not promote peeling of the surrounding coating. However, the reason why coated steel sheets based on electrolytic lead-galvanized steel sheets, which have excellent corrosion resistance, have not been commercialized until now is that, as in the case of galvanized steel sheets, it is necessary to improve the adhesion with the paint film and the corrosion resistance. This method could not be put to practical use because there was no suitable pretreatment such as zinc phosphate treatment or chromic acid treatment, and no suitable primer. In other words, the present invention provides coating film adhesion equal to or better than that of galvanized steel sheets by subjecting electrolytic lead-galvanized steel sheets to a specific pretreatment, and on top of this, an adhesive layer containing anti-corrosion pigments is held with a non-woven fabric. By applying the coating in a coated state and then forming a decorative paint layer on top of it and forming a pattern on the surface of the decorative paint layer, it is possible to achieve excellent corrosion resistance and weather resistance, as well as decorative properties that do not cause scratches on the base material. This is a manufacturing method for patterned decorative steel sheets. The present invention will be explained in detail below. First, the electrolytic lead-plated steel sheet that is the object of the present invention can be easily plated to a predetermined thickness using conventional electrolytic lead plating methods such as a boufating bath, a silicate bath, a sulfamic acid bath, and an alkaline bath. In the present invention, the plating thickness must be 0.1μ or more. If the thickness is less than this, there will be no corrosion resistance under the corrosion-resistant coating, and the function of the electrolytic leaded layer/organic coating system will deteriorate. Regarding the upper limit of the plating thickness, there is no problem even if it is quite thick, but since it is an electroplating method, the standard is 10μ, and making it thicker than this will require a long time for plating, which will be disadvantageous in terms of the process. . Of course, even if the plating thickness is greater than this, there will be no problem in terms of corrosion resistance and workability. It is also possible to eutectoid tin, copper, nickel, cobalt, antimony, etc. to the electrolytic lead plating layer itself, or to make it a eutectoid plating layer with various metal oxides dispersed therein. It works effectively as long as it does so. Note that the steel plate referred to in the present invention includes copper-containing steel such as ordinary low carbon steel or weathering steel,
This applies to cold-rolled steel sheets of low alloy steel such as sulfuric acid-resistant steel and seawater-resistant steel, as well as pickled hot-rolled steel sheets. Next, as a pretreatment, an alkaline aqueous solution with a pH of 9 or higher is preferable, but mere immersion cleaning is insufficient and activation of the plated layer surface by alkaline electrolytic cleaning or a strong brushing polishing effect is required. for example
A method of activating the lead-plated layer surface by brushing and cleaning with a 3% aqueous solution of ortho-silicate (PH13.5) at 90°C, followed by electrolytic cleaning with the same solution, followed by hot water cleaning with brushing. It has been found that by adopting this method, adhesion of the primer and paint film can be obtained that is equal to or better than that obtained when zinc phosphate treatment is applied to a galvanized steel sheet as a base. In addition, in the case of electroplating as in the present invention, other than alkaline electrolytic cleaning, there is also a method in which the oxide film on the surface of the plating layer is scraped off using a brushing roll containing an abrasive material or a buff roll containing an abrasive material to expose an active surface. . In addition, since electrolytic lead-plated steel sheets usually have defects in the plating film such as pinholes, anti-rust pigments such as zinc chromate, strontium chromate, calcium molybdate, etc. are used to protect the film defects with a primer coating layer. Apply a primer containing anti-rust pigment (e.g. one-component epoxy, acrylic/epoxy, two-component acrylic/phenol-modified vinyl, etc.) to a thickness of 1 to 15 μm and bake at a baking temperature of 175 to 240°C. and bake to form an adhesive layer. A nonwoven fabric such as glass wool or polyester having a thickness of 0.035 to 0.3 mm is laminated and adhered to one or both sides of this adhesive layer. Furthermore, a baking type adhesive similar to the above adhesive is applied and baked to form an adhesive layer. In this way, the adhesive layer is applied onto the steel plate while being held by the non-woven fabric. Note that the adhesive layer may be applied only to the steel plate, or may be applied by impregnating the nonwoven fabric in advance. When the nonwoven fabric is impregnated with an adhesive in advance, the nonwoven fabric may be adhered to the steel plate with the impregnated adhesive, and the impregnated adhesive may be used as a binder between the nonwoven fabric and the decorative paint layer. Next, a decorative paint layer such as a baking type paint such as vinyl chloride sol or vinyl fluoride sol or a normal room temperature curing type paint is formed on the adhesive layer held by the nonwoven fabric or on the nonwoven fabric. When applying baking type paints such as vinyl chloride sol, apply so that the thickness of the decorative paint layer is 50 to 400μ.
Bake at 240℃. For forming this decorative paint layer, roller coating, doctor coating, flow coating, etc. are used. Furthermore, a pattern is applied to the surface of this decorative paint layer, but the pattern may be formed simultaneously with the formation of the decorative paint layer or after the decorative paint layer is formed. Usually, after forming a decorative paint layer, it is pressed against the surface of an embossing roller or the like to form an uneven pattern such as an embossed pattern. In addition, aggregate such as metal powder such as aluminum powder or copper powder or synthetic resin flakes colored in a color different from the color of the decorative paint is mixed into the relatively high viscosity decorative paint.
For example, when this decorative paint is scraped up with a pick-up roll and transferred to a coating roll that rotates in the opposite direction, the high viscosity of this paint creates an uneven flow pattern, causing uneven distribution of aggregate. By this application roll, a flow pattern-like uneven pattern is formed on the surface of the decorative paint layer as shown in FIG.
Furthermore, if the reverse natural method is employed when roll coating the decorative paint containing the above-mentioned aggregate mixed therein, a smooth flowing pattern on the surface as shown in FIG. 4 can be formed. On the other hand, on the surface on which the nonwoven fabric layer is not formed, a back paint layer is formed on the adhesive layer using vinyl chloride sol, vinyl fluoride sol, or color top coat as described above. In the present invention, as described above, adhesive is applied to the electrolytic leaded steel plate while it is held in the non-woven fabric, and a decorative paint layer is formed on this, so that a large amount of the adhesive held in the non-woven fabric is applied. At the same time, the decorative paint layer is not directly adhered to the steel plate by an adhesive, but is adhered to the nonwoven fabric adhered to the steel plate. Even if it is, there is an advantage that it can be firmly and firmly attached. Moreover, since the nonwoven fabric layer is formed of glass wool nonwoven fabric, there is no risk of deterioration of the nonwoven fabric layer even if the adhesive or paint is baked at high temperatures. Furthermore, the presence of the non-woven fabric layer improves impact resistance, and it is possible to obtain a decorative steel sheet protected by a scratch-resistant decorative paint layer that is given elasticity, and even when the decorative steel sheet is bent. The decorative paint layer is resistant to scratches,
In addition, this decorative paint protects the steel plate and provides corrosion resistance.
It has weather resistance, and since a pattern is formed on the surface of this decorative paint layer, the decorative paint layer exhibits cushioning properties due to the cushioning action of the nonwoven fabric layer.
An uneven pattern can be formed without softening the decorative paint layer too much, and a decorative steel sheet with decorative properties can be easily obtained. Furthermore, although the decorative steel sheet has such excellent properties, it can be easily obtained. The present invention will be specifically explained below using Examples. Example 1 After cleaning a cold-rolled steel plate with a thickness of 0.35 mm, electrolytic lead plating was applied to both sides under the conditions shown below.
A decorative steel sheet having a coating structure as shown in FIG. 1 was manufactured.

[Table] First, 3% sodium orthosilicate solution (PH13.5) heated to 90℃ was applied to the surface of the electrolytic leaded steel plate 3, which consists of the steel plate 1 and the electrolytic leaded layer 2, with a nylon brushing roll. After spray cleaning while brushing, electrolytically clean with a solution of the same concentration, then wash with hot water, form an activation layer 4 on both surfaces of the lead-plated layer 2, and coat one surface with strontium and chromate preventive. Two-component acrylic with rust pigment.
A phenol-modified vinyl adhesive was applied to a thickness of 10 μm and baked at 220° C. for 1.5 minutes to form a primer layer 5. Next, a glass wool nonwoven fabric 6 with a thickness of 0.1 mm is layered and adhered to one side of the primer layer 5, and the same amount of the same adhesive as above is applied onto this nonwoven fabric 6, and the primer layer 5' is baked under the same conditions. And so. Next, on the primer layer 5' held on this nonwoven fabric, a vinyl chloride sol decorative paint having the following composition was applied to a thickness of 200 μm using a coating roll and baked at 200° C. for 1.5 minutes to form a decorative paint layer 8. Next, an embossing roll was pressed against this surface to form an uneven pattern.
On the other hand, on the other surface where the glass wool non-woven fabric is not formed, the same adhesive as above is applied to a thickness of 5μ with a primer layer of 5", baked under the same conditions, and then the same vinyl chloride sol paint as above is applied. thickness 100
Coat on μ and bake at 200℃ for 1.5 minutes Back coating layer 7
And so. Composition of vinyl chloride sol cosmetic paint Vinyl chloride resin (=1700)
100 parts (parts by weight) DOP 65 parts Dibasic lead phosphite 3 parts Titanium white 10 parts Pigment 10 parts When compared with steel plate, the results are shown in the attached table. From this result, patterned decorative steel sheets made of electro-leaded steel sheets plated to a thickness of 0.1 to 10 μm have corrosion resistance and weather resistance, and do not cause flaws or cracks even when bent, making them attractive for decoration. It was excellent.

[Table] Example 2 Example 1 on both sides of weather-resistant copper-containing steel with a thickness of 0.5 mm
Under the same conditions as above, decorative steel plates having a smooth flow pattern (so-called roving pattern) on the surface as shown in FIG. 4 were produced on electrolytic lead plated steel plates each having a thickness of 5 μm. That is, as shown in FIG. 2, both sides of an electrolytic leaded steel plate 3 consisting of a weather-resistant copper-containing steel plate 1 and an electrolytic leaded layer 2 are polished with a Scotch Bright Roll containing an abrasive and washed with hot water to form the leaded layer 2. An activation layer 4 is formed on both surfaces of the glass wool nonwoven fabric with a thickness of 0.1 mm, and an acrylic adhesive containing calcium and molybdate rust-preventing pigments is pre-impregnated on one surface, and the nonwoven fabric is coated with the impregnated adhesive. 6' was adhered and baked at 220°C for 1.5 minutes. Next, 100 parts of PVC (=1700), DOP65, was applied on the primer layer held by this non-woven fabric.
1 part, 3 parts dibasic lead phosphite, and 15 parts titanium white, colored blue to a thickness of approx.
10% hard vinyl chloride resin flakes with a length of 100 μ and 3 mm
The mixed sol paint was applied to a thickness of 200 μm using the natural reverse method to form a decorative coating layer 8' having a smooth flowing pattern (so-called roving pattern) on the surface as shown in FIG. The patterned decorative steel sheet produced in this manner had the same performance as Example 1, and had excellent decorative properties.

[Brief explanation of the drawing]

Figure 1, Figure 2, Figure 3 a, b, Figure 4 a, b
These are a cross-sectional view and a plan view of a decorative paint layer showing an embodiment of the decorative steel sheet of the present invention. 1... Steel plate, 2... Electrolytic leaded layer, 3... Electrolytic leaded steel plate, 4... Activated layer, 5, 5',
5″...Primer layer, 6,6′...Nonwoven fabric layer, 7
... Back coating layer, 8, 8'... Decorative paint layer.

Claims (1)

[Scope of Claims] 1. The surface of the lead-plated layer of an electro-leaded steel plate obtained by plating lead on a thin steel plate to a thickness of 0.1 to 10 μm by electroplating method is subjected to brushing polishing or alkaline electrolytic cleaning. to activate the surface, hold an adhesive layer containing rust-preventing pigments on it with a non-woven fabric to form an adhesive layer, then form a decorative paint layer on top of it, and apply an adhesive layer to the surface of the decorative paint layer. A method for producing a patterned decorative steel sheet, characterized by forming a pattern. 2. The method for producing a patterned decorative steel sheet according to claim 1, wherein the decorative paint is a vinyl chloride sol paint. 3. The method for manufacturing a patterned decorative steel sheet according to claim 1 or 2, wherein the pattern is an embossed pattern. 4. The method for producing a patterned decorative steel sheet according to claim 1 or 2, wherein the pattern is a flowing pattern.