KR100544470B1 - Resin coat composition for shielding of electromagnetic wave and manufacturing method of resin coated steel sheet - Google Patents

Abstract

The present invention relates to a resin coating liquid composition effective to block electromagnetic waves and a method for producing a resin coated steel sheet using the same,

Provides a resin coating liquid composition having excellent electromagnetic wave absorption and blocking effect by administering an epoxy-based curing agent, an alumina sol and an antifoaming agent as a main solution, and adjusting solid content of the entire solution using pure water. It is. In addition, the steel sheet excellent in the electromagnetic wave absorption and blocking effect coated with the resin coating liquid composition is provided.

The steel sheet produced by the present invention is excellent in shielding against electromagnetic waves generated in home appliances, automobiles, communication devices, and the like, particularly in the low and ultra low frequency range (1 GHz to 50 Hz).

Electromagnetic waves, steel sheet, alumina sol, resin coating liquid, polyethylene-acrylic copolymer resin

Description

RESIN COAT COMPOSITION FOR SHIELDING OF ELECTROMAGNETIC WAVE AND MANUFACTURING METHOD OF RESIN COATED STEEL SHEET}

The present invention relates to a resin coating liquid composition effective to block electromagnetic waves and a method for manufacturing a resin coated steel sheet using the same, and more particularly, to electromagnetic waves generated from electronic products such as TVs, radios, computers, refrigerators, and copiers, and automobiles and communication devices. The present invention relates to a resin coating liquid composition which is a steel sheet treatment material which effectively absorbs or blocks and a method of manufacturing a resin coated steel sheet using the same.

At present, a lot of electronic products, such as electromagnetic waves are generated, the electromagnetic wave is harmful to the human body has been developed a lot of methods to block the electromagnetic waves. Among them, Japanese Patent Laid-Open No. 11-307361 introduces a technique in which a shielding performance is improved by applying a film containing a metal, rather than a ferromagnetic material of a thick film of 2 m or more, on the surface thereof to improve conductivity at the joint. This method prevents the penetration and emission of electromagnetic waves by using a material with high conductivity, and uses non-ferromagnetic materials such as zinc, gold, silver, and copper among metals.

On the other hand, European Patent No. 0,186,145 is a composite material of metal and ceramic made of lead + zinc + niobium, lead + zinc + tantalum or lead + zinc + tungsten in the high frequency region (1 MHz-1 GHz) to increase the frequency shielding effect. Here's how. However, this method is difficult due to the mixing of metals and ceramics, and has a weak shielding performance. In addition, European Patent No. 0,107,863 relates to electromagnetic shielding by mixing a polymer material and a metal material such as palladium or nickel, and is known to have good electromagnetic shielding and absorption according to a frequency domain. There are many differences depending on the particle size of the metal, and there is a disadvantage in that the shielding performance is lowered due to difficulty in uniform distribution of metal components.

In addition, Japanese Patent No. 61-163231 introduces a method of shielding electromagnetic waves with a material produced by mixing a predetermined amount of elements such as copper, manganese, nickel, and iron with aluminum. However, this method has disadvantages in that the shielding ability is localized, the performance is weak, and the effect is low, especially in the low frequency (KHz region). In addition, Japanese Patent No. 2000-36419 improves shielding ability by making a steel sheet, but its manufacturing method is complicated and expensive. On the other hand, Japanese Patent Laid-Open No. 7-86788 discloses that the electromagnetic shielding performance is improved by modifying the surface of the steel sheet using a laser beam. However, this method has a disadvantage in that it is practically difficult to control the laser in a certain direction and thickness.

Accordingly, an object of the present invention is to provide a resin coating liquid composition excellent in shielding against electromagnetic waves generated in home appliances, automobiles, communication devices, etc., in particular, low and ultra low frequency regions (1 GHz to 50 Hz).

Another object of the present invention is to provide a resin coated steel sheet manufacturing method excellent in the shielding property using the resin coating liquid composition.

According to one aspect of the invention,

Using polyethylene-acrylic copolymer resin as the main solution,

Here, the epoxy-based curing agent is 2-10% by weight relative to the solid content weight of the main solution,

10-50% by weight of the alumina sol (Alumina Sol) relative to the solids weight of the main solution and

Antifoam is administered at 0.01-0.1% by weight relative to the weight of solids of the subject solution and

Provided is a resin coating liquid composition excellent in electromagnetic wave absorption and blocking effects, which is achieved by adjusting the solid content of the total solution to 10-40% by weight using pure water.

According to another aspect of the present invention,

On the surface layer surface of the base metal of the general low carbon steel sheet, the resin coating liquid composition is applied so as to have a dry film thickness of 1.0-40 μm and baked by baking at a temperature of 100-200 ° C. An excellent steel sheet manufacturing method is provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The resin coating liquid composition having an electromagnetic wave shielding ability of the present invention is based on an emulsion-type polyethylene-acrylic copolymer resin that is easily applied to a steel sheet in water solubility, and an epoxy curing agent for forming a firm film, and an alumina having an electromagnetic wave shielding capability. This is accomplished by administering an antifoaming agent that reduces foam during sol and mixing, followed by adjusting the solids content of the total solution using pure water (deionized water).

The composition ratio of each component of the resin coating solution composition should be maintained at a ratio of 2-10% by weight of epoxy curing agent, 10-50% by weight of alumina sol, and 0.01-0.1% by weight of antifoaming agent, based on the weight of solid content of polyethylene-acrylic copolymer resin, which is the main solution. do.

When the dose of the epoxy curing agent is less than 2% by weight, sufficient curing reaction does not occur and a hard film is not formed. Therefore, electromagnetic wave shielding performance is difficult to be exhibited by peeling the film during coating of the steel sheet. Poor workability It is preferable to use the epoxy hardening | curing agent (number average molecular weight 400-4000) whose solid content is 10-30%.

The alumina sol is a material that has a major influence on the electromagnetic shielding performance, thereby increasing the conductivity of the film to effectively exhibit the electromagnetic shielding effect, and if added below 10% by weight, the shielding effect is weak and 50% by weight. When added above, an effective coating cannot be achieved due to the viscosity increase of the resin solution. In addition, the alumina sol is preferably used by dispersing aluminum oxide (Al ₂ O ₃ ) to 10-25% by weight in water using an anion stabilizer.

The antifoaming agent is to prevent deterioration of workability due to foaming when the resin coating solution composition and coating application of the present invention are applied. An antifoaming agent such as a silicone-based solution, for example, a silicone-based solution and an antifoaming agent having a similar effect When added to less than 0.01% by weight, the effect of suppressing such foam generation is weak and when added to more than 0.1% by weight, the overall resin properties such as coating quality is reduced.

The resin coating liquid composition having excellent electromagnetic shielding performance of the present invention configured as described above may be applied to a general low carbon steel sheet to effectively block electromagnetic waves generated from electronic products, automobiles, and communication devices.

The resin coating liquid composition of the present invention is applied to a general low carbon steel sheet as a base metal, that is, coated on the surface layer surface (both sides or cross-sections) of such a base metal to produce an electromagnetic shielding steel sheet. Specifically, the resin coating liquid composition is applied on a base metal to have a dry film thickness of 1.0-40 μm and subjected to baking at a temperature of 100-200 ° C. to prepare a steel sheet having electromagnetic shielding ability.

In the present invention, the reason for using a general low-carbon steel sheet is that household appliances such as computers, washing machines, refrigerators, and TVs are made of low-carbon steel sheets, and in order to effectively block electromagnetic waves generated from these household appliances, Because the effect should be given. In particular, since the low carbon steel sheet is mainly used in electronic devices that emit low-frequency and ultra-low frequency electromagnetic waves, it is possible to achieve a more effective electromagnetic shielding effect if the low-carbon steel sheet is given an effect of suppressing the emission of electromagnetic waves.

In addition, if the low-carbon steel sheet in addition to the treatment of the reactive or coated chromate is used in addition to the electromagnetic shielding effect, which is the main object of the present invention, it is preferable to obtain the effect of improving the corrosion resistance against the external corrosion factor.

In addition, when the coating thickness on the base metal of the resin coating liquid composition is less than 1.0㎛, the shielding effect by the radio wave penetration depth is weak, whereas when the thickness is more than 40㎛ poor adhesion of the coating layer is reduced shielding ability. In addition, when the baking temperature is less than 100 ℃ during coating, the curing reaction of the resin film due to heat is not sufficient, so that a solid coating layer is not formed. When the baking temperature is higher than 200 ℃, the electromagnetic shielding performance is deteriorated due to the crack of the base and the coating layer. It will also cause an increase.

When the resin coating liquid composition of the present invention is also applied to a steel sheet, the resin coating liquid composition additionally exhibits a good effect on the corrosion resistance and surface anti-fingerprint properties of the steel sheet, and the metal plated steel sheets such as chromium, zinc and nickel on the steel sheet. Also shows good electromagnetic wave blocking effect.

The electromagnetic wave shielding effect mechanism according to the present invention is not precisely identified, but according to the results of the embodiment, the electromagnetic wave incident on the base metal within the above-mentioned range is absorbed by the resin layer, and the electromagnetic wave reflected on the base metal is also appropriate. It is estimated that it is extinguished by the ratio and the electromagnetic wave shielding ability is improved.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are described to more easily disclose the contents of the present invention, and the scope of the present invention is not limited to the following examples.

Example

A resin having a composition as shown in Table 1 below, wherein the metal is 0.6 mm thick and contains 0.015% of carbon, and a general low carbon steel sheet (other trace elements other than carbon may be included as impurities). The coating solution composition (solid content of the total solution is 18% by weight) was prepared various steel sheet products by varying the conditions of the film thickness and baking temperature. Then, the steel sheet products were examined for electromagnetic shielding properties in the 0.5KHz, 100KHz, 1MHz and 100MHz region, respectively. At this time, the electromagnetic shielding measurement method was based on the test method specified in ASTM A698-74. In addition, the shelf life of the solution was left to stand at room temperature for 30 days after the preparation of the solution, and visually observed to evaluate the gelation phenomenon or the presence or absence of sludge in the solution. ), The transparent tape was adhered thereon, and immediately after peeling off, the peeling degree of the coating film was evaluated.

Electromagnetic Shielding Ability of Steel Sheets According to Resin Coating Solution Composition and Steel Sheet Manufacturing Conditions division number Resin coating liquid composition ratio (weight ratio) Coating layer thickness (㎛) Curing temperature (℃) Solution Storage Coating Film Adhesion Electromagnetic shielding characteristics (db) subject Epoxy Curing Agent Defoamer (silicone solution) Alumina sol 0.5 KHz 100 KHz 1 MHz 100 MHz Comparative example One - - - - - - - - 11.1 23 43 46 Comparative example 2 100 3 0.05 5 5 120

13.6 24 43 47 Inventive Example 3 100 3 0.05 10 5 120

18.0 32 49 53 Inventive Example 4 100 3 0.05 20 5 120

18.1 33 49 54 Inventive Example 5 100 3 0.05 30 5 120

18.0 32 50 53 Inventive Example 6 100 3 0.05 30 5 120

18.2 34 51 55 Inventive Example 7 100 3 0.05 40 5 120

18.2 34 50 54 Inventive Example 8 100 3 0.05 50 5 120

18.3 35 52 56 Comparative example 9 100 3 0.05 70 5 120 X △ 17.7 33 49 52 Comparative example 10 100 3 0.05 90 5 120 X △ 16.9 32 46 50 Comparative example 11 100 3 0.05 30 0.3 120

12.9 26 40 47 Comparative example 12 100 3 0.05 30 0.5 120

15.8 31 47 50 Inventive Example 13 100 3 0.05 30 1.0 120

17.8 33 49 52 Inventive Example 14 100 3 0.05 30 10 120

18.3 36 52 55 Inventive Example 15 100 3 0.05 30 20 120

18.4 37 52 56 Inventive Example 16 100 3 0.05 30 40 120

18.4 37 53 56 Comparative example 17 100 3 0.05 30 50 120

X 15.6 28 44 48 Comparative example 18 100 3 0.05 30 5 90

X 16.1 29 45 49 Inventive Example 19 100 3 0.05 30 5 180

18.2 35 51 55 Comparative example 20 100 3 0.05 30 5 220

△ 15.9 27 44 47 Comparative example 21 100 One 0.05 30 5 120

X 15.7 29 45 49 Inventive Example 22 100 7 0.05 30 5 120

18.4 35 52 56 Comparative example 23 100 12 0.05 30 5 120 X △ 17.2 29 47 53 Inventive Example 24 100 3 0.1 30 5 120

18.3 33 50 54 Comparative example 25 100 3 0.2 30 5 120 X △ 17.4 30 48 51

; 우수, △; 보통, X; 저조

; Excellent, △; Usually, X; Low

 * Evaluation criteria for excellent, normal and low

Solution Storability:

Excellent-no sedimentation and flotation after 15 days

Moderate-Small amounts of sediment or suspended matter within 3 to 15 days

Low-Precipitation or suspended solids within 3 days of manufacture, solution gelation during evaluation

Coating Adhesion:

Excellent-no peeling

Normal-small amount of peeling

Low-Full Peel

* Comparative Example 1 is a low carbon steel sheet (uncoated)

* Inventive Example 5 uses a base steel sheet treated with a reactive chromate (20 mg / m 2) on a low carbon steel sheet.

* Inventive Example 6 uses a base steel sheet treated with a coated chromate (50 mg / m 2) on a low carbon steel sheet.

* Other invention examples and comparative examples use low carbon steel sheet

Example 1 Comparative Examples 2, 9 and 10 and Inventive Examples 3-8

Except for changing the proportion of the alumina sol in the resin coating liquid composition ratio, and prepared under the same conditions as in the other examples to examine the electromagnetic shielding characteristics.

Example 2 Comparative Examples 11, 12, and 17 and Inventive Examples 13-16

Except for changing the composition ratio and baking temperature of the resin coating solution was prepared under the same conditions as in the other examples to examine the electromagnetic shielding characteristics.

Example 3 Comparative Example 18, 20 and Inventive Example 6, 19

The composition of the resin coating solution and the coating thickness were maintained under the same conditions, except that the baking temperature was changed.

Example 4 Comparative Examples 21 and 23 and Inventive Examples 6 and 22

Except for changing the ratio of the epoxy-based curing agent in the composition ratio of the resin coating solution was prepared under the same conditions as in the other examples to examine the electromagnetic shielding characteristics.

<Example 5> Comparative Example 25 and Inventive Examples 6,24

Except for changing the proportion of the silicone-based antifoaming agent in the composition ratio of the resin coating solution was prepared under the same conditions as in the other examples to examine the electromagnetic shielding characteristics.

As can be seen from the above examples, the resin coating solution composition according to the present invention exhibited extremely good electromagnetic wave shielding properties at the proper ratio and proper thickness and baking temperature.

Steel sheet coated with the resin coating liquid composition of the present invention can effectively absorb and shield the electromagnetic waves generated in home appliances, automobiles, communication devices, etc., in particular low-frequency and ultra-low frequency region (1GHz-50Hz).

Claims (4)

Using polyethylene-acrylic copolymer resin as the main solution, Here, the epoxy-based curing agent is 2-10% by weight relative to the solid content weight of the main solution, 10-50% by weight of the alumina sol (Alumina Sol) relative to the solids weight of the main solution and Antifoam is administered at 0.01-0.1% by weight relative to the weight of solids of the subject solution and The resin coating liquid composition excellent in the electromagnetic wave absorption and blocking effect made by adjusting the solid content of the total solution to 10-40% by weight using pure water. The method of claim 1, wherein the alumina sol has an electromagnetic wave absorption and blocking effect, characterized in that the aluminum oxide (Al ₂ O ₃ ) having excellent electromagnetic shielding performance is dispersed in water by 10-25% by weight using an anion stabilizer. Excellent resin coating liquid composition. On the surface layer surface of the base metal of the general low carbon steel sheet, the resin coating liquid composition according to claim 1 or 2 is applied so as to have a dry film thickness of 1.0-40㎛ and produced by baking at a temperature of 100-200 ℃. Steel sheet manufacturing method with excellent electromagnetic wave absorption and blocking effect. 4. The method according to claim 3, wherein the base metal is one in which a reactive or coated chromate is additionally treated on a general low carbon steel sheet.