JPH08224541A - Production of color coated zinc-aluminum alloy plated wire - Google Patents

Abstract

PURPOSE: To enhance corrosion resistance and to keep beautiful apapearance over a long period of time by forming a phosphate film on the surface of a wire in a predetermined adhesion amt. and applying an undercoat layer and a topcoat layer thereon in predetermined film thickness and baking and drying both layers in the same drying oven and cooling the baked wire to predetermined temp. or lower by air and cooling water. CONSTITUTION: A zinc-aluminum alloy plated wire 1 is passed through the pickling tank 3a, washing tank 3b, surface adjusting tank 3c, chemical forming treatment tank 3d, washing tank 3e and drying part 3f of a coating pretreatment process part A to form a phosphate film on the wire in an adhesion amt. of 0.3-0.7g/m<2> . Subsequently, undercoat (c) is formed on the wire in a coating film thickness of 2-8μm by the dip roll 5 of the first coating material tank 4 of a coating part B and topcoating (d) is formed thereon in a coating film thickness of 12-18μm by the dip roll 7 of a second coating material tank 6. Next, the coated wire is sent to a drying oven (c) to be backed and dried. After drying, cooling water and air are sprayed on the baked wire from the cooling water nozzles 14, 14 and air nozzle 15 of a cooling part D to cool the surface temp. of the wire to 60 deg.C or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colored coated zinc-aluminum alloy plated wire.

[0002] Galvanized wire is widely used as a constituent member of steel wire products such as wire mesh (fence), net, stranded wire and cable, but even if it is painted, the iron base material and zinc plating will reduce the corrosion However, there is a problem that the corrosion from the damaged surface of the coating film progresses rapidly, and when the corrosion progresses inside the coating film, the corrosiveness causing swelling or peeling of the coating film is insufficient. As a countermeasure, zinc-aluminum alloy plated wire has been developed. Since this zinc-aluminum alloy plating has twice the corrosion resistance of zinc plating, its field of application is expanding, but such zinc-aluminum alloy plating wire is generally silvery in color, and therefore it is monotonous and matches the surrounding environment. There are many cases where they do not do it, and there is a problem in terms of product value in the present day when design and aesthetics are important even for outdoor products.

The present invention was devised to solve the above-mentioned problems, and its purpose is to provide a colored coating zinc-aluminum which has excellent corrosion resistance, is colorful, and can maintain its aesthetic appearance over a long period of time. An object of the present invention is to provide a method for efficiently manufacturing an alloy-plated wire at a relatively low cost.

[0004]

In order to achieve the above object, the present invention is a method of applying a colored coating to the surface of a zinc-aluminum alloy plated wire, wherein the zinc-aluminum alloy plated wire is coated with a coating amount as a coating base treatment. 0.3-0.7 g / m ² phosphoric acid film is applied, an undercoat layer with a film thickness of 2-8 μm and an overcoat layer with a film thickness of 12-18 μm are applied on this phosphoric acid film, and the undercoating process and the topcoating process are the same. It is configured such that it is baked and dried using a baking and drying furnace, and that the coating film is cooled immediately after each baking and drying step by controlling the wire surface temperature to 60 degrees or less by air and cooling water.

The present invention preferably uses the coating equipment having the following constitution. Downstream of the pretreatment process section including the chemical conversion treatment tank, a first paint tank in which an immersion roll is placed in the undercoat paint and a second paint tank in which an immersion roll is placed in the topcoat paint are installed in parallel, and the first paint tank is provided. A head sheave forming a pair with each dipping roll is arranged above and above the second paint tank, and a common baking and drying furnace is installed vertically between the head sheave and the outlet side of the first and second paint tanks. A water cooling nozzle and an air nozzle are installed in a row along the iron wire moving path between the outlet of the drying furnace and the head sheave. Then, with this equipment, painting is performed in the following steps. A zinc-aluminum alloy plated wire with a phosphoric acid film on its surface is introduced into the first paint tank for undercoating, and the undercoated zinc-aluminum alloy plated wire rising from the dipping roll is passed through a common baking and drying oven. Immediately after this, it is bake-dried and rapidly cooled by a water-cooling nozzle and an air nozzle, then turned downward through a head sheave and introduced into a second paint tank for top-coating, and the above-mentioned zinc-aluminum alloy-plated wire is commonly used. It is again passed through the baking and drying oven to be baked and dried, and immediately thereafter, it is rapidly cooled by a water cooling nozzle and an air nozzle and guided to the winding side via the head sheave.

[0006]

[Function] A zinc-aluminum alloy plated wire is coated with a phosphoric acid film with a coating amount of 0.3 to 0.7 g / m ² as a coating base, so it is possible to improve the adhesion with the undercoat paint. As a first layer, an undercoat with a coating thickness of 2 to 8 μm is applied, and as a second layer with an overcoat of 12 to 18 μm, this sufficiently thin coating film provides good workability such as bending and twisting after coating. can do. In addition, since the baking and drying of each process of undercoating and topcoating are performed in the same furnace, there is no waste of equipment and heat.In addition, cooling after baking and drying undercoating and baking and drying of topcoat is performed with a water cooling nozzle and an air nozzle, and the wire surface temperature is Is controlled to 60 ° C. or less, so that the coating film surface is not scratched by rubbing with the wire transfer means,
A beautiful colored coating with good corrosion resistance can be obtained. In addition, the zinc-aluminum alloy plated wire 1 having a phosphoric acid film on its surface is introduced into the first paint tank 4 to perform undercoating,
The undercoat zinc-aluminum alloy plated wire 1 ′ rising from the dipping roll 5 is passed through a common baking and drying oven C to be baked and dried, and immediately thereafter, it is rapidly cooled by a water cooling nozzle 14 and an air nozzle 15, and then continuously passed through a head sheave 10. It is turned downward and introduced into the second coating tank 6 for top coating, and the top coating zinc-aluminum alloy plated wire 1 "
Is passed through the common baking and drying oven C again to be baked and dried, and immediately thereafter, it is rapidly cooled by the water cooling nozzle 14 and the air nozzle 15 and guided to the winding side via the head sheave 11, the installation space is reduced. In addition to saving energy, the baking and drying are also compact, so that economically efficient two-layer color coating can be performed.

The present invention will be described below with reference to the accompanying drawings.
1 to 4 show an outline of the method of the present invention and equipment used, and FIG. 5 shows an enlarged process of forming a colored coated zinc-aluminum alloy plated wire in the method of the present invention. No. 1 is a zinc-aluminum alloy plated wire, and as shown in FIG.
A zinc-aluminum alloy plating layer b having a required thickness is provided on the top. The method for obtaining the zinc-aluminum alloy plating layer b is arbitrary. Two-bath type, that is, hot-dip galvanizing is performed as the first step, and then Zn is added as the second step with an Al content of 3% or more.
Either a method of hot dip plating with an -Al alloy bath or a method of direct hot dipping with a one-bath method, that is, a Zn-Al alloy bath with an Al addition amount of 3% or more may be used.

The zinc-aluminum alloy plated wire 1 is wound around a swift 2, and downstream of the swift 2, a coating pretreatment process section A, a coating section B, a baking and drying oven C and a cooling section D are provided. ing. The coating pretreatment process section A is the same as a known one, and in this example, the pickling tank 3a and the water washing tank 3 are used.
b, a surface conditioning tank 3c, a chemical conversion treatment tank 3d, a water washing tank 3e, and a drying section 3f are sequentially arranged.

In the coating section B, a first paint tank 4 containing an undercoat paint c and having a dip roll 5 inside, and a second paint tank 6 containing a top paint d and having a dip roll 7 inside are arranged side by side. The first coating tank 4 and the second coating tank 6 are provided with paint squeezing means 8 and 9 at the outlet side portions thereof. The undercoating material c and the topcoating material d are good even in a severe environment of use. It is preferable to use a baked synthetic resin system that exhibits excellent durability and that withstands the processing force well even when plastic working such as bending and twisting is performed after painting, and is resistant to peeling and scratches. As the undercoating c, a phosphoric acid film applied to the zinc-aluminum alloy plated surface and one having good adhesion to the topcoating, for example, epoxy resin type, alkyd resin type, melamine resin type, urethane resin type, phenol resin type, urea It is appropriately selected from a resin system and a composite coating of two or more of these. Further, the durability of these is further improved by using a rust preventive pigment. As the topcoat paint d, those having good adhesion to the undercoat paint, excellent solvent resistance and concealing properties, aesthetics, gloss, and excellent heat resistance are preferable. For example, a polyester resin system is preferably used. The coloring pigment of the color is mixed.

The paint squeezing means 8 and 9 may be a ball of a bearing, a solid squeezing tool using a granular resin (for example, polyethylene or polypropylene), or a fluid squeezing device. The latter is, for example, the undercoating c for the lower opening,
A cylindrical seal box dipped in the top coat d is used. The seal box has a guide hole at the top to allow the passage of a wire coated with paint, and a side is provided with an inlet for gas, such as air, and the inside of the seal box is filled with this gas and a part of the guide hole is provided. The paint adhering to the wire is squeezed by flowing out from the. The coating thickness is controlled by the linear velocity and / or the gas. The linear velocity is generally 5 to 40 m / min, and the gas controls the flow rate in this linear velocity range according to the coating thickness.

Above the first coating tank 4 and the second coating tank 6, there are provided a first head sheave 10 and a second head sheave 11 which form a pair with the dipping roll 5 and the dipping roll 7, respectively. The baking / drying oven C is vertically installed in a region between the first and second head sheaves 10 and 11 and the first and second coating tanks 4 and 6. The distance from the lower end (charge inlet) of the baking / drying oven C to the first and second coating tanks 4 and 6 is set to a dimension sufficient for the coating film that has finished drawing to be self-repaired. The tunnel-shaped furnace body 12 of the baking / drying furnace C has a passage width exceeding the pulling side movement path of the undercoat zinc-aluminum alloy plated wire 1'and the topcoat zinc-aluminum alloy plated wire 1 ", and a heating means is provided in the furnace. 13 is arranged so that baking drying of the undercoat paint c and baking baking of the topcoat paint d can be performed in a common furnace instead of separate furnaces. The heating means 13 may be a hot air nozzle, A resistance heating heater and an infrared heater are preferable in terms of efficiency.

The first head sheave 10 of the second paint tank 6 is made by passing the undercoat zinc-aluminum alloy plated wire 1'through the dipping roll 5 of the first paint tank 4 through the baking and drying furnace C and then turning it downward. The second head sheave 11 is a means for leading to the dipping roll 7. The second head sheave 11 pulls up the overcoated zinc-aluminum alloy-plated wire 1 ″ via the dipping roll 6 and, after passing through the baking and drying furnace C again, as shown in the drawing. It is a means to lead to a winding machine.

The cooling section D is the outlet 12 of the baking and drying furnace C.
0 and the first and second head sheaves 10 and 11 are respectively arranged on the pulling-side movement paths, and each is composed of a plurality of stages of water-cooling nozzles 14 and air nozzles 15 therebelow. It is preferable that the air nozzle 15 also has a plurality of stages. The water-cooling nozzle 14 at each stage may be a single hole rod-shaped nozzle or a slit-shaped nozzle, and in any case, for example, 5 to 20 so as to cross the pulling-side movement path toward the water receiving pan 140 on the opposite side of the same path. The cooling water at a temperature of ℃ is discharged, and the wire 1 ', 1 "after baking and drying is passed through the fountain flow for rapid cooling. The air nozzle 15 exits from the outlet 120 of the baking and drying furnace C. This is for blowing air to the wires 1 ′, 1 ″ immediately after baking for primary cooling, and for blowing off water droplets from the upper water cooling nozzle 14 flowing down along the coating film surface.
An air nozzle 16 is arranged on the wire return side path between the first head sheave 10 and the second paint tank 6. This air nozzle 16 is for completely removing the water droplets that have been transferred to the wire 1 ′ after baking and drying the undercoat before reaching the second paint tank 6. The air nozzle 15 is selected to have a sufficient amount and pressure to blow off water droplets attached to the undercoat and overcoat wires. The water cooling nozzle 14 has the number of stages, the temperature of the cooling water to be used, and the amount of cooling water so that the wire temperature immediately before the head sheaves 10 and 11 can be set to 60 ° C. or less within 1 to 3 seconds under the linear velocity condition. One or more conditions are set appropriately.

In obtaining a colored coated zinc-aluminum alloy plated wire, the zinc-aluminum alloy plated wire 1 is pulled out from the swift 2 at a linear speed of 5 to 40 m / min by driving a winding machine, and firstly, acid is applied. After being guided to the washing tank 3a, foreign substances on the surface such as an oxide film are dissolved and removed with hydrochloric acid, sulfuric acid, etc., then washed with water with the washing tank 3b, and subjected to surface conditioning with the surface conditioning tank 3c containing sodium or the like.
It is introduced into the chemical conversion tank 3d, where a dense phosphoric acid film as a coating base is formed, washed with water in the water washing tank 3e, and then dried by passing through the drying unit 3f. The amount of the phosphoric acid film deposited is preferably 0.3 to 0.7 g / m ² . If the adhered amount is less than 0.3 g / m ² , phosphoric acid crystal growth is insufficient and peeling of the coating film occurs in a rough portion, which is not suitable. However, if the deposition amount exceeds 0.7 g / m ² , the crystal becomes coarse and the strength of the phosphoric acid film itself becomes weak,
It is not suitable because it peels off at that part.

The zinc-aluminum alloy plated wire 1 which has been subjected to the phosphoric acid film conversion treatment is continuously introduced into the first paint tank 4, and is immersed in the undercoat paint c through the dipping roll 5 arranged therein. The undercoating is applied by the above, passes through the lower half circumference of the dipping roll 5, passes through the squeezing means 8, and is pulled upward in the vertical direction. The zinc-aluminum alloy plated undercoat wire 1 ′ at this time is shown in FIG. 4 (b), and the thickness t ₁ of the undercoat coating layer c ′ should be 2 to 8 μm from the viewpoint of rust prevention and workability. . The reason is that if it is thinner than 2 μm, a sufficient rust preventive effect cannot be exhibited, and if it is thicker than 8 μm, the workability is deteriorated.

Undercoat zinc-aluminum alloy plated wire 1 '
Is passed through the squeezing means 8 and the coating film is self-repaired and then introduced into a vertical vertical baking and drying oven C. While passing through this, the heating means 13 heats it at 250 to 280 ° C. for 45 to 55 seconds. It can be baked and dried. The zinc-aluminum alloy plated wire 1 ′ that has been baked and dried after undercoating is air-cooled by the air blown from the air nozzle 15 immediately after exiting from the outlet 120 of the baking and drying furnace C, and immediately after that, with the jet water from the water cooling nozzle 14. It is forcibly cooled by contact. Zinc-aluminum alloy-plated wire 1'which was prevented from cracking in the coating film by primary cooling with air without water cooling immediately after baking and drying, and which was baked and dried after undercoating
Surely has a surface temperature of 60 ° C. or lower. Moreover, since the air from the air nozzle 15 blows off the water droplets attached by the downstream water cooling, it is possible to prevent the trouble that the water droplets enter the baking and drying furnace C and lower the temperature inside the furnace.

The zinc-aluminum alloy plated wire 1'which has been sufficiently cooled, baked and dried in this way is turned by the first head sheave 10 and descends. Since the wire surface temperature is 60 ° C. or less when the direction is changed by the first head sheave 10, even if the surface of the undercoating film is scratched even when slidingly contacted while being bent with a relatively small curvature,
A good undercoat function can be exhibited. The wire 1'turned down by the first head sheave 10 and lowered,
Air is blown from the air nozzle 16 before being introduced into the second paint tank 6, whereby water droplets on the wire surface by the water cooling nozzle 14 are completely removed. Therefore, the top coat d
Can maintain the prescribed composition and properties.

The wire 1'is dipped in the top coat d by the dipping roll 7 of the second paint tank 6 to apply the top coat onto the surface of the undercoat layer c'which has been baked and dried. Such a topcoat zinc-aluminum alloy plated wire 1 ″ rises vertically through the dipping roll 7, and the topcoat coating film layer d ′ is adjusted to a predetermined coating film thickness t ₂ by the paint squeezing means 9. The coating thickness t ₂ is 12 to 18 μm from the viewpoint of the hiding power for hiding the color of the undercoat and the subsequent workability.
Should be. That is, if it is thinner than 12 μm, the color of the undercoating film is transparent and visible, and if it is thicker than 18 μm, the workability is deteriorated.

Topcoat zinc-aluminum alloy plated wire 1 "
Is then introduced into a common baking and drying furnace C, and is baked and dried under the above conditions by heating from the heating means 13 while passing through the baking and drying furnace C. Immediately after exiting from the outlet 120 of the baking and drying furnace C, the wire which has been bake-dried by topcoating is primarily cooled by the air nozzle 15 and the upper water-cooling nozzle 14
Secondary cooling by jet water from the air nozzle 1
The water droplets attached to the wire are removed by 5. As a result, the wire which has been bake-dried by the overcoat reaches the second head sheave 11 in a state where the wire surface temperature is adjusted to 60 ° C. or less as in the above, and the wound wire is wound downstream from here in a state where the coating film surface is not scratched. Air-cooled for 1 to 7 minutes before reaching the machine,
It is taken up. As a result, a zinc-aluminum alloy-plated wire with a colored coating as shown in FIG. 4 (c) can be obtained.
Although the wire shown in the drawing is processed by four wires, the number of wires is not limited to this, and more wires may be used. Further, the number of stages of the water cooling nozzle 14 and the air nozzle 15 of the cooling section D is not limited.

Next, examples will be shown. Wire diameter as wire 4.
A 0-mmφ iron wire plated with a zinc-aluminum alloy having a thickness of 40 μm was used, and a two-layer coating was applied with four wires. 1) As the undercoat paint, a composite resin paint of epoxy resin and melamine resin was used. A polyester resin paint was used as the top coat paint, and it was decided to manufacture a zinc-aluminum alloy-plated iron wire with a green color. 2) A solid squeeze is used as the paint squeezing means, and the baking / drying oven has a furnace length of 6 m and a passage width of 0.9 with a built-in infrared heater.
m vertical tunnel furnace was used for both undercoat baking and topcoat baking. 3) In the cooling section, two air nozzles are arranged 200 mm from the outlet of the baking and drying furnace, and 200 mm from the air nozzle.
Three water cooling nozzles were arranged on the upper level. 4) Pulling the wire at a linear speed of 7 m / min by a winding machine, applying a phosphoric acid film with an adhesion amount of 0.5 g / m ^{2 in} the pretreatment section, and applying an undercoat-baking according to the route of FIGS. 1 and 2. Drying-Applying overcoat-Baking and drying, air-cooling, water-cooling, and winding. The baking and drying conditions during this period were 260 ° C. and 51 seconds. As for the cooling conditions, water at 8 ° C. was jetted from each water cooling nozzle at 15 l / min, and air was jetted from the air nozzle. 6) According to the above process, zinc-aluminum alloy plating is
The undercoating film thickness is 5 μm and the topcoating film thickness is 15 μm. The colored coating has no surface scratches and the coating quality is J
No damage such as cracking or peeling in the self-diameter 2 times winding test specified by IS, no cracks or peeling in the self-diameter 1 time winding test, cracking or peeling in the self-diameter 1 time winding-rewinding test. No abnormality, weather resistance is 1 near the coast of the industrial zone.
No abnormality after yearly exposure, JIS standard salt spray test 50
Good results were obtained with 0 hrs indicating no abnormality and good solvent resistance test.

[0021]

According to the first aspect of the present invention described above, a zinc-aluminum alloy plated wire having a corrosion resistance more than twice as good as that of zinc plating is used, and it has good adhesion to an undercoat film. A thick phosphoric acid film was applied, and a thin undercoating and a relatively thicker overcoating were applied, so the color of the base was concealed and it was beautiful and could withstand subsequent processing. In addition, the wire temperature is controlled to 60 ° C or less by using air and water immediately after each baking and drying after the undercoating and the overcoating. Does not scratch the membrane surface. Therefore, due to the corrosion resistance of the zinc-aluminum alloy plating and the two-layer coating, it is possible to obtain a color filament product that has extremely high durability and matches the environment even when used in the most heavy-duty industrial areas. Further, since the undercoating and the topcoating are each baked and dried in the same furnace, the control is easy and the excellent effect that the cost can be reduced can be obtained.
According to the second aspect, it is possible to save the space for painting and baking and drying, and further, since the baking and drying process is performed in the same furnace, the cost can be reduced, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a side view showing an outline of a manufacturing method and equipment of a colored zinc-aluminum alloy plated wire according to the present invention.

FIG. 2 is a partially cutaway front view of the coating section to the cooling section.

FIG. 3 is a rear view of the same.

FIG. 4 is an enlarged perspective view of an outlet side region of a baking and drying furnace.

FIG. 5 is an enlarged sectional view showing stepwise a colored zinc-aluminum alloy plated wire manufactured according to the present invention.

[Explanation of symbols]

 1 Zinc-aluminum alloy plated wire A Pretreatment part B Coating part C Baking and drying oven D Cooling part 4 First paint tank 5 Immersion roll 6 Second paint tank 7 Immersion roll 8, 9 Paint squeezing means 10 First head sheave 11 Second Head sheave 14 Water cooling nozzle 15 Air nozzle c Undercoat paint c'Undercoat film layer d Overcoat paint d'Overcoat film layer

Claims (2)

[Claims] 1. A method for applying a colored coating to the surface of a zinc-aluminum alloy plated wire, the coating amount being 0.3 to 0.7 g / m as a coating base treatment.
² phosphoric acid film is applied, and the film thickness is 2 on this phosphoric acid film.
-8 μm undercoat layer and a coating thickness of 12-18 μm are applied, and the undercoating step and the overcoating step are both baked and dried using the same baking and drying furnace, and immediately after each baking and drying step, the wire surface is subjected to air and cooling water. A method for producing a colored coated zinc-aluminum alloy plated wire, characterized in that the coating film is cooled by controlling the temperature to 60 degrees or less. 2. A downstream of a pretreatment process section including a chemical conversion treatment tank,
The first paint tank 4 in which the dipping roll 5 is arranged in the undercoat paint and the second paint tank 6 in which the dipping roll 7 is arranged in the topcoat paint are arranged in parallel, and each of the first paint tank 4 and the second paint tank 6 is provided. Head sheaves 10 and 11 forming a pair with each dipping roll are arranged above the head sheaves 10 and 11 and the first and second paint tanks 4 and 6.
A common baking / drying oven C is vertically installed between the outlets of the above, and a coating facility in which a water-cooling nozzle 14 and an air nozzle 15 are provided in a row in a wire moving path between the exit of the common baking / drying oven C and the head sheaves 10 and 11 Then, the zinc-aluminum alloy plated wire 1 having a phosphoric acid film on the surface is introduced into the first paint tank 4 for undercoating, and the undercoated zinc-aluminum alloy plated wire 1 ′ rising from the dipping roll 5 is prepared. The water-cooling nozzle 14 and the air nozzle 1 are provided immediately after passing through the common baking and drying oven C for baking and drying.
5 and then turn downward through the head sheave 10 and then introduced into the second paint tank 6 for topcoating, and the topcoat zinc-aluminum alloy plated wire 1 ″ is passed through the common baking and drying oven C again. 2. The colored coated zinc-aluminum alloy plated wire according to claim 1, wherein the colored coated zinc-aluminum alloy plated wire is led to the winding side through the head sheave 11 immediately after being rapidly cooled by the water cooling nozzle 14 and the air nozzle 15. Production method.