KR100659891B1 - Fluoriated ink-print coated steel sheet - Google Patents

Abstract

According to the present invention, a chromate layer is formed on a base plate, and a polyester undercoat is formed on the chromate layer. Then, it is coated with fluorine paint and coated with fluorine cree after printing in various patterns using a naturally-dried fluorine printing ink. It provides a weather resistant fluorine-printed steel sheet.

Description

Manufacturing method of fluorine-printed steel sheet {Fluoriated ink-print coated steel sheet}

1 is a cross-sectional view of the product of the present invention

(Key sign for drawing)

1. Holding layer 2. Chromate layer 3. Undercoat layer 4. Barrier coating layer

5. Printing Ink Coating Layer 6. Cree Coating Layer

The present invention relates to a method for producing a fluorine-printed coated steel sheet. More specifically, the present invention relates to a fluorine-printed coated steel sheet using physical properties of a common fluorine color steel sheet having excellent weather resistance by printing in various patterns using a fluorine type printing ink.

The general printed steel sheet is usually polyester type or acrylic type, which is excellent in printability and paintability of printed steel sheet, but generally in terms of weather resistance, it is generally somewhat lower than that of conventional polyester type color steel sheet. Weather resistance is required when the main purpose of printed steel sheet is interior and exterior building materials. That is to say, in order to meet the requirements from the demands, it was considered that the printed steel sheet should be manufactured in fluorine type with excellent weather resistance, but since the fluorine ink has crystallinity in the case of conventional thermoplastic fluorine resin, it is melted at a high temperature. Although it must be dried at high temperature, the conventional printed steel sheet can be worked only when it is dried in nature or at low temperature, so it is practically impossible to apply in actual work, and the adhesion between ink and base paint is not good, so it cannot be applied as a printed steel sheet. There were so many problems.

Accordingly, the present invention provides a high weather resistance fluorine-printed steel sheet produced by forming a chromate layer on a steel sheet and forming a fluorine-based base, a fluorine-type ink, and a fluorine-type clear layer on the formed chromate layer in order to solve the above problems. The purpose is to provide.

The present invention forms a chromate layer coated with chromium on a base plate, and a polyester undercoat is formed on the chromate layer, and then coated with a fluorine-based paint and various patterns using a naturally-dried fluorine-type printing ink thereon. High-durability fluorine-printed steel sheet in which a fluorine-type creeper layer is formed after printing, that is, the present invention is to provide a highly weather-resistant fluorine-printed steel sheet by forming all of the barrier paint, the printing ink, and the clear paint into fluorine resin type. There is a characteristic.

The reason why the chromate layer is formed by the chromate treatment is that the corrosion resistance of the material is poor and the adhesion between the material and the coating film is deteriorated if the chromate treatment is not performed.

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Figure 1 is a schematic diagram showing a cross-sectional view of the product of the present invention will be described in more detail and in detail the present invention as an embodiment below.

The steel sheet produced by the method of the present invention is a plated steel sheet, a zinc-aluminum plated steel sheet such as a galvanized steel sheet or a so-called supergallium steel sheet, or an aluminum steel sheet, and the like. The undercoat layer 3 is formed after washing with an alkali degreasing agent to perform chromate coating treatment (2).

That is, the present invention basically coats the polyester undercoat 3 on the plated steel sheet 1 by applying an undercoat after the alkali degreasing and chromate treatment (2), as described in claim 1. Painted and formed in thickness of 3-7 micrometers. It is then heated and dried at 200 to 220 ° C. for 30 to 40 seconds to coat the undercoat layer 3 on the chromate layer 2. Next, after coating the fluorine-type barrier coating layer 4 with a coating film thickness of 17 to 23 µm, the barrier coating film layer is formed by heating and drying at 242 to 255 ° C for 50 to 60 seconds. Next, the fluorine ink 5 is printed so as to have a dry film thickness of 1 μm or less, and then dried at room temperature, and then coated with a dry film thickness of 10 to 20 μm. By heating and drying for ˜60 seconds, a highly weather-resistant fluorine-printed coated steel sheet coated with a cree layer on the printing ink is produced.

The reason for coating the bottom coat with 3 ~ 7㎛ dry coating thickness after alkali degreasing and chromate treatment is that when the thickness of the bottom coat layer is less than 3㎛, the adhesion with the small coated steel sheet 1 is poor and the corrosion resistance is poor and white blue occurs. Have possession. In addition, when the coating thickness of the undercoat is more than 7㎛, the adhesion and corrosion resistance are slightly increased, but there is no economic feasibility. In addition, if the coating thickness of the barrier paint is less than 17㎛ may cause problems in the management of each lot due to the generation and non-uniformity of the plate color, there is a possibility that white blue may occur due to poor corrosion resistance. In addition, if it exceeds 23㎛, corrosion resistance may increase but coating swelling may occur.

On the other hand, if the thickness of the cree layer is less than 10㎛, ultraviolet rays are transmitted to change the ink layer, causing problems of chalking and peeling of the coating film, and the solvent resistance is poor, which may cause problems in corrosion resistance and weather resistance, and when the film thickness exceeds 20㎛ All physical properties increase, but the film swells easily and surface defects are likely to occur. In addition, the lower limit of the heat drying and heating drying time to each temperature range is insufficient heat drying, respectively, resulting in poor coating and poor adhesion, and the upper limit of each temperature range and heating drying is due to surface roughness due to excessive drying. Brings uneconomical effects such as surface defects such as wrinkles and heat loss.

Undercoat paints should be selected and applied as coatings with excellent adhesion and corrosion resistance to the chromate layer of the plated steel sheet, as well as adhesion with barrier paints. , Printing and drying properties should be excellent. In addition, CREE paint has excellent adhesion to ink, and is selected and manufactured as a paint having excellent corrosion resistance, weather resistance (UV resistance) and processability.

The polyester undercoat layer 3 of the present invention comprises 25 to 30% by weight of a linear polyester resin, 5 to 10% by weight of melamine resin, 2 to 5% by weight of phenol resin, 20 to 25% by weight of a pigment, a binder and the like. It is characterized by coating and forming a paint which is 3 to 5% by weight of an additive, 20 to 30% by weight of an aromatic hydrocarbon solvent, 3 to 5% by weight of an ester solvent, and 3 to 5% by weight of an ether solvent. Barrier coating layer 4 of the thermoplastic fluororesin 27 to 33% by weight, acrylic resin 6 to 10% by weight, inorganic color pigments 25 to 35% by weight, silica-based pigment 1 for clarity and adhesion to the paint, if necessary % Or less is added. In addition, for adhesion, 1 to 3% by weight of an additive such as a binder and a solvent are coated with a paint of 30 to 40% by weight of isophorone. In addition, the fluorine ink 5 may contain 35 to 45 wt% of a naturally-dried thermosetting fluororesin, 2 to 5 wt% of an acrylic resin, 25 to 40 wt% of an inorganic color pigment, and additives such as binders. Fluorine-type creeper layer for printing with an ink of 5% to 10% by weight of aromatic hydrocarbon, 2 to 5% by weight of ester type, and 5 to 10% by weight of ketone type as a solvent by weight and forming a transparent coating layer on the ink. (6) is coated with a clear paint composed of 38 to 45% by weight of thermoplastic fluororesin, 8 to 12% by weight of acrylic resin, 2 to 5% by weight of additive, and 38 to 45% by weight of isophorone, and is excellent in weatherability according to the present invention. Small print coated steel sheet will be manufactured.

Table 1 shows each resin, pigment, solvent, and component composition range according to the present invention.

When manufacturing the fluorine-printed steel sheet, the adhesion of the barrier paint and ink, ink, and cree paint, which are main parts, must be excellent, and ink workability (transferability, dryness) and weather resistance must be excellent. Therefore, the present invention is to prepare a printed coated steel sheet using a paint composed of the above composition range in consideration of these basic points.

The numerical values, pigments, solvents, etc. according to the respective coating layers described above are summarized according to FIG.

The unit of the number shown in Table 1 means weight%, respectively, and the lower limit of each composition range represents the lower limit of the effect of the composition addition, and the upper limit of each composition range represents the upper limit of corrosion resistance, adhesion or weather resistance. do.

In the present invention, the reason for the chromate treatment according to claim 1 is that if the chromate treatment is not performed, the corrosion resistance is poor and the material and the adhesiveness deteriorate.

In addition, the reason for setting the weight range of the undercoat layer of claim 2 is because the coating properties (workability, appearance, anti-foaming property) and physical properties (corrosion resistance, processability, adhesion) in the undercoat work are affected by the weight range.

In addition, when the barrier layer is composed of the content of claim 3, it is similar to a general fluorine color steel sheet, but an additive such as a binder and a special acrylic resin are added to the general fluorine paint to improve adhesion with ink. Although the transferability of the ink is excellent, weather resistance may be somewhat degraded when the ink is exposed to the outside as it is. It also affects ink adhesion even when the weight range is exceeded.

In addition, the reason for constituting the content of claim 4 of the fluorine-type ink is that conventional ink for printing steel sheet is polyester or acrylic type, and since weather resistance is less than 50% level compared with fluorine-type ink, Fluorine inks should be used, and many years of research and numerous tests have shown that within the weight range of claim 4, the adhesion, drying and weathering properties are the best, and the coating surface defects are generated the least.

The reason why the fluorine-type creeper layer is constituted by claim 5 is that the coating film of the printing ink is thinner than 1 탆 or less, so that the coating film may be damaged by an external impact, and the weather resistance may also be deteriorated without the cree coating. Of course, the weight range setting for each composition affects the ink, adhesiveness and weather resistance, and the lower limit has little effect, so there is no desired effect, and when the upper limit is exceeded, the physical properties such as surface appearance and adhesion are excessive. Rather it degrades.

Table 1

The composition range of the paint having the above characteristics is developed in the process of the present invention to be suitable for the fluorine-printed coated steel sheet capable of expressing various patterns and various colors of the printed steel sheet and having excellent corrosion resistance, weather resistance and processability.

This will be described in more detail as follows.

In terms of the characteristics of the coating material of the present invention, 2-5% by weight of a phenol resin was added for adhesion and corrosion resistance with the base material, and in particular, silica and an extender pigment were added for adhesion with the barrier paint. The anti-corrosive pigment content was maintained so that the interlayer adhesion with the barrier paint was excellent (the lower limit of rust preventive effect: the lower limit of rust preventive effect, upper limit: limit adhesion deterioration).

The characteristics of the present invention are that the barrier, ink and the clear paint are all made of fluorine resin, and since the fluorine element has a large electronegativity compared with other elements, when the fluorine bonds with carbon, the bonding electrons are strongly close to the fluorine atom nucleus. A bond with a small polarization rate is formed, and a short distance can be formed because the atomic radius of the fluorine atom is larger than the atomic radius of the hydrogen atom, but smaller than that of the other elements, resulting in stable bond formation with large electronegativity and high energy. Can be. Therefore, fluorine resin-type barrier paints, printing inks and cree paints are excellent in non-tackiness, water repellency, slipperiness, heat resistance, chemical resistance and weather resistance because they cannot interact even when other materials are close to the fluorine compound.

Therefore, the present invention is to apply the printed steel sheet in all fluorine type in order to secure the excellent durability performance of such fluorine element. As a characteristic of each system, barrier paint was designed by adding additives such as acrylic resin and binder for adhesion with ink.

Thermoplastic fluororesin printing inks, which are commonly used in general fluorine paints, have crystallinity and are melted at high temperatures and thus have problems in coating workability. Therefore, thermosetting fluorine resins are used in the present invention. The characteristic of the fluororesin is a fluoro olefin (Fluoro Olefin) and a hydrocarbon-based vinyl ethylene monomers are mutually copolymerized, and can be dried at room temperature.

Cree paints are designed to add additives such as acrylic resins and binders for adhesion with inks like base paints. This improved adhesion to the fluorine ink and improved ink transferability.

EXAMPLE

The following example is to evaluate the characteristics of the fluorine-printed steel sheet prepared by applying the ink and paint developed by the present invention to a coated steel sheet.

However, this embodiment is an example of a very small part of the present invention.

The characteristics were evaluated by adhesion of ink with barrier and cree paint, ink transferability, ink dryness, and weather resistance after cree coating.

-Adhesiveness: Evaluation of adhesiveness by tape test after cross cut (100/100)

Ink transferability: Evaluation of ink transferability in roll coating

Ink Dryability: Assessed as dry time after ink printing

-Weather resistance: After maintaining 3000 hours in the accelerated weather resistance test W-O-M tester to evaluate the weather resistance by measuring the color change and gloss change

On the other hand, the test to determine the physical properties for the above fluorine ink was tested in Example 1 (invention) to Example 5, according to the composition of the composition for comparing Example 1 and other embodiments according to the present invention Fluorine inks are shown in Tables 2 and 3 below.

Table 2 Fluorine ink for fluorine-printed steel sheet (unit: weight%)

The present inventors were based on Table 1, and again tested for an example determined by each composition component, the test method was in accordance with the criteria of Table 4. The main characteristics of the products according to Examples 1 to 5 of Table 2 were as shown in Table 3.

Table 3

As can be seen from the results of Tables 2 and 3 above, in Example 4 in which the thermoplastic resin and the acrylic resin were used in the fluorine ink for printed steel sheet and the thermosetting resin was not contained at all, adhesiveness, transferability, dryness, etc. All of them were poor, on the contrary, even though the thermoplastic resin was not contained, when the acrylic resin was contained together with the thermosetting resin, the physical properties were generally good, but in the absence of the acrylic resin, the transferability was poor. However, in the case of Example 2 with too much acrylic resin exceeding 10%, it was shown that glossiness retention rate fell compared with Example 1. In addition, it was found that there is a difference in dryness between the case of evenly using aromatic hydrocarbons, esters, and ketones as a solvent. However, the weather resistance was generally good.

Table 3 shows the test results of the coating film properties of the fluorine-printed steel sheet manufactured according to Example 1 (present invention) of Table 1 and Table 2 according to the present invention.

Table 4

Test items, test methods and devices in Table 3 were in accordance with each of the standards of the American standard standards ASTM, and the test results are gloss, pencil hardness, workability (OT), impact resistance, adhesion, solvent resistance, chemical resistance, corrosion resistance, etc. All of them were good, and the accelerated weather resistance was evaluated by the result of 3000 hrs test by xenon cycle test, and the gloss retention was over 90%.

As described above, according to the evaluation results described above, the fluorine-printed coated steel sheet of the present invention not only ensures high weatherability and the best durability by applying fluorine to the printed steel sheet as well as various patterns of existing types, but also has good ink transferability. Printed steel sheet can be manufactured.

Claims (5)

After chromate treatment (2) on the base layer (1) of the plated steel sheet, the undercoat is applied with a dry coating thickness of 3 to 7 μm, and then undercoated. Then, the undercoat layer (3) is dried by heating and drying at 200 to 220 ° C. for 30 to 40 seconds. In the production of a highly weather-resistant fluorine-printed coated steel sheet which forms a barrier layer 4 by forming a barrier layer 4 by coating with a barrier coating and then applying a dry coating thickness of 17 to 23 µm. In order to form the barrier layer as a fluorine resin barrier layer, thermoplastic fluorine resin 27 to 33% by weight, acrylic resin 6 to 10% by weight, color pigment 25 to 35% by weight, silica pigment 1% by weight or less, binder 1 to 3 A barrier paint composed of 30% by weight and 30-40% by weight of isophorone solvent is coated on the undercoating layer, and then printed on the surface of the barrier coating layer with a naturally-drying thermosetting fluorine ink (5), and then fluorine The barrier paint, printing ink, and clear paint are formed by forming a fluorine resin-type clear coating layer 6 by heating and drying the coated steel sheet coated with the clear paint at a normal dry film thickness for 50 to 60 seconds at 242 to 255 ° C. Method for producing a high weather resistance fluorine-printed coated steel sheet, characterized in that all of the fluorine resin composition. delete delete 2. The fluorine-type ink 5 according to claim 1, wherein the fluorine ink 5 is 35-45 wt% of thermosetting fluororesin, 2-5 wt% of acrylic resin, 25-35 wt% of color pigment, 2-5 wt% of binder, aromatic hydrocarbon solvent. A method for producing a highly weatherable fluorine-printed steel sheet, comprising 5 to 10% by weight, 2 to 5% by weight of an ester solvent, and 5 to 10% by weight of a ketone solvent. The fluorine-type creeper layer (6) according to claim 1, wherein 38 to 45% by weight of thermoplastic fluororesin, 8 to 12% by weight of acrylic resin, 2 to 5% by weight of binder, and 38 to 45% by weight of isophorone solvent are added. A method for producing a high weather resistant fluorine-printed coated steel sheet by coating a paint.

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