KR100536953B1 - Coating method of metal sheet using a japanning - Google Patents

Abstract

The present invention relates to a coating method of a metal sheet using a lacquer, and more particularly, a pre-treatment process for the surface of the metal sheet, the printing process by offset printing or silk-screen printing, the drying process of the printed metal sheet, The present invention relates to a coating method of a metal sheet using a lacquer comprising a lacquer step applied to the metal sheet using a mixed solution of filtered lacquer and varnish and a drying step of the lacquered metal sheet.

Since the coating method of the metal sheet according to the present invention uses a printing method, by applying lacquer to the printed metal sheet in various forms, it is possible to mass-produce a lacquer coated metal sheet having a variety of patterns, absorbing harmful electromagnetic waves, durability It is excellent and far-infrared emissivity is more than 95%, it can be applied to materials such as mobile phones, notebook computers, automotive interior materials, building materials.

Description

Coating method of metal sheet using a japanning}

The present invention relates to a coating method of a metal sheet using lacquer, and more particularly, a pretreatment process for the surface of the metal sheet, the printing process by offset printing or silkscreen printing, the drying process of the printed metal sheet, filtered lacquer And it relates to a coating method of a metal sheet using a lacquer comprising a lacquer step of applying to the metal sheet using a mixture of varnish (varnish) and a drying step of the lacquered metal sheet.

It is known that raw lacquer or lacquer liquid collected from lacquer trees contains urushiol as its main ingredient, and also contains a small amount of rubber, nitrogenous substances, and moisture. Lacquer is a kind of natural resin that has been used in thousands of years in Korea, China and Japan, mainly applied to wooden products, and has been used in large quantities in the production of daily necessities such as cabinets, bowls, cutlery, and tableware. It is a well-known fact that it has the advantage of excellent insect repellency and insulation, and especially excellent storage.

Recently, efforts have been made to use not only wood products but also various applications such as synthetic polymers (Korean Patent Laid-Open Publication No. 2000-0024493), ceramics and metal containers (Korean Patent Publication No. 2002-0072903) using lacquer. .

However, there is no disclosure about the use of a lacquer that is vividly coated while maintaining various printed patterns, and the lacquer coating causes an allergic reaction to the human body before it is cured, thereby avoiding its use by general users. There was a lot of inconvenience. The hardening of the lacquer coating is produced from the surface where water and oxygen are most in contact, and since the oxygen and moisture permeability of the lacquer coating are very low, UV drying is used for curing the lacquer into the coating, or a lot of coating and curing are performed. There was a lot of trouble, such as repetition, and industrial production was difficult due to the uneconomical cost that increased the price compared to the production.

The present invention has been made to solve the problems of the prior art,

An object of the present invention is to provide a coating method of a metal sheet using a lacquer that can be lacquered in a variety of patterns using a printing method.

Coating method of a metal sheet using a lacquer according to the present invention for achieving the above technical problem, a pre-treatment process for the surface of the metal sheet, the printing process by offset printing or silk-screen printing, the drying process of the printed metal sheet, The present invention relates to a coating method of a metal sheet using a lacquer comprising a lacquer step applied to the metal sheet using a mixed solution of filtered lacquer and varnish and a drying step of the lacquered metal sheet. At this time, it is preferable to further include a lacquer coating process containing PMMA (polymethyl methacrylate) and MMA (methyl methacrylate) on the lacquered metal sheet subjected to the drying process and a drying process of the metal sheet coated with the lacquer. Do.

Hereinafter, the present invention will be described in more detail.

The metal sheet to be applied to the present invention may be metals such as titanium steel, stainless steel, aluminum and aluminum alloy, preferably aluminum. The metal sheet has a thickness of 0.3 to 2 mm washed by surface polishing. The pretreatment process for the surface of the metal sheet may be classified into physical methods, chemical methods, primers and the like. Physical methods include sand blast, short blast, dry ice blast, hairline, and vibration. Chemical methods include aluminum deposition, anodization, electroplating and alkaline degreasing in all tests.

 Primer treatment is used when it is impossible to bond with inorganic paints such as plastic, and is used for silk screen printing for the purpose of hot air and various decorations and labels. The pretreatment process as described above is to increase the adhesive force at the time of printing and to increase the corrosion resistance. In the present invention, anodization treatment is most preferable to prevent material oxidation through chromate treatment.

In the printing process by offset printing or silkscreen printing on the pretreated metal sheet, the desired design is printed on the metal sheet in advance and dried at 150 to 200 ° C. for 30 to 90 minutes immediately after the printing process. Perform the process.

The lacquer process on the metal sheet, which has been subjected to the printing process and the drying process, is a process of preparing a mixed solution of lacquer and varnish, and then applying it to the metal sheet.

The lacquer used in the present invention is not subject to the origin of Korea, China, Japan, Southeast Asia, etc., and these lacquer liquids may show some differences in composition depending on the origin, but all can be applied. Lacquer liquid used in the present invention is used by filtration with a filter paper, to prepare a mixed liquid containing 95 to 98% by weight of the filtered lacquer liquid and varnish 2 to 5% by weight. The prepared lacquer and varnish mixture is not limited thereto, but is preferably applied by silk screen printing. Immediately after the application of the lacquer and varnish mixture is carried out a drying step of drying at 130 ~ 180 ℃ for 30 minutes to 90 minutes.

At this time, in order to increase the glossiness and to enhance weather resistance, the lacquer containing the polymethyl methacrylate (PMMA) and methyl methacrylate (PMMA) to the lacquered metal sheet subjected to the drying process and the metal coated with the lacquer It is preferable to further include the drying process of a sheet.

PMMA is an acrylic resin containing MMA monomer as a main raw material, and in the present invention, the mixture containing PMMA and MMA is 95 to 99% by weight based on the total weight of lacquer, wherein the addition ratio of PMMA and MMA is 5 to 7 : 5 to 3 is preferable, and PMMA: MMA is 6: 4 is most preferred in terms of transparency and physical properties.

The lacquer mixture is not limited thereto, but is preferably applied by silk screen printing. Immediately after application of the lacquer mixture, a drying process is performed at 80 to 120 ° C. for 30 to 90 minutes. The temperature at the time of drying at each said step is an optimal temperature condition for removing cracking or peeling of the coating layer during the lacquer curing.

As shown in FIG. 2, the metal sheet manufactured by the above method has a metal sheet 10 from the bottom, an oxide film layer 20 by a pretreatment process, a design printing layer 30, a lacquer coating layer 40, and lacquer. The coating layer 50 is formed in order.

 Since the metal sheet coated by the method of the present invention absorbs harmful electromagnetic waves, has excellent durability and excellent far-infrared emissivity, it can be applied to materials such as mobile phones, laptop computers, automobile interior materials, and the like.

Hereinafter, the configuration of the present invention will be described in detail through Examples, Experimental Examples and Tables. However, the scope of the present invention is not limited to the claims of the present invention by the following examples, experimental examples and tables.

Example 1 Coating of Metal Sheet Using Lacquer

1 is a process chart for a method for coating a metal sheet according to the present invention. Specifically, in the present invention, an aluminum sheet (H-26, Alcoa Co., Ltd.) having a thickness of 0.5 mm from 0.25 to 0.30 kg is ground polished and washed with water. Subsequently, the surface of the aluminum sheet was cleaned with a degreasing agent to form an oxide film having a thickness of 1.5 to 2.5 μm, and then 2 kg of an acid solution diluted in water with chromate was used as a pretreatment.

Then, the pattern designed through offset printing was printed on the aluminum sheet, and then dried at 180 ° C. for 1 hour in a box oven (solar electricity).

After filtering the Chinese fresh lacquer with a filter paper, and then preparing a mixed solution of 5% by weight of varnish to the total weight of the filtered lacquer, the mixed solution is applied to the printed aluminum sheet by a silk screen to a thickness of 1.5 ~ 2.5㎛ Then, it was dried for 1 hour at 160 ℃ in a box oven (see Figure 3a).

Example 2 Coating of Metal Sheet and Lacquer Using Lacquer

Lacquer (plex6788, ROHM Co., Ltd.) containing a mixed solution of PMMA and MMA is 6: 4 to the lacquered aluminum sheet subjected to the process of Example 1 After coating by silk screen, and dried in a box oven for 1 hour 100 ℃ to prepare a lacquer coated aluminum sheet (see Figure 3b).

Experimental Example 1. Measurement of hardness and gloss

The thickness, hardness and gloss of the lacquer coating film of the aluminum sheet coated with lacquer prepared by Examples 1 and 2 were measured.

At this time, the hardness was evaluated by the pencil hardness according to JIS D 0202.8.10, the gloss was evaluated by the incidence angle of 60 degrees by the gloss meter of BYK company and the results are shown in Table 1 below.

Properties of Lacquer Coating Film Example 1 Example 2 thickness 2.25㎛ 3.45㎛ Hardness 2H 1H Polish 80% 90%

As shown in Table 1, it was possible to produce a sheet excellent in hardness and gloss compared to the thickness of the lacquer coating film.

The above embodiments and drawings are merely for the purpose of describing the contents of the invention in detail, and are not intended to limit the scope of the technical idea of the invention, the present invention described above is a general knowledge in the technical field to which the present invention belongs. It is to be understood that various changes, modifications, and changes can be made without departing from the spirit and scope of the present invention, and are not limited to the embodiments and the accompanying drawings. Together, they should be judged to include equality.

Since the coating method of the metal sheet according to the present invention according to the present invention uses a printing method, by applying lacquer to the printed metal sheet in various forms, it is possible to mass-produce a lacquer coated metal sheet having various patterns, Absorption and durability of harmful electromagnetic waves and far infrared emissivity is more than 95%, it can be applied to materials such as mobile phones, notebook computers, automobile interior materials, building materials.

1 is a process chart for the coating method of a metal sheet according to the present invention.

2 is a cross-sectional view of a metal sheet manufactured by the method of the present invention.

Figure 3 is a photograph of the aluminum sheet produced by the method of the present invention, Figure 3a is an aluminum sheet treated to the lacquer process, Figure 3b is a photograph of an aluminum sheet to which the lacquer coating process is added after the lacquer process.

Claims (4)

delete delete Pretreatment to the surface of the metal sheet, printing by offset printing or silkscreen printing, drying process at 150-200 ° C. for 30 to 90 minutes of printed metal sheet, 95 to 98% by weight of filtered lacquer and varnish Lacquer process applied by silk screen printing on the metal sheet using a mixture of 2 ~ 5% by weight, drying process at 130 ~ 180 ℃ for 30 to 90 minutes of the lacquered metal sheet, PMMA to the lacquered metal sheet coating process by silkscreen printing of lacquer containing polymethyl methacrylate and MMA (methyl methacrylate) and drying process at 80-120 ° C. for 30 to 90 minutes of the metal sheet coated with lacquer Coating method of metal sheet using lacquer is configured by. The method of claim 3, wherein The lacquer is a coating method of a metal sheet using lacquer, characterized in that PMMA: MMA is 5 to 7: 5 to 3.