KR100523841B1 - Compound of Conductive sheet and method for preparing it - Google Patents

Abstract

  The present invention relates to a conductive sheet composition and a method for manufacturing the same, more specifically, 60 to 98% by weight of a flat conductive metal powder having a surface ratio of 150 to 450 and 2 to 40% by weight of a crosslinkable non-halogen resin are the basic composition components. It is contained in the present invention, since the emulsifier or surfactant is added to 0.01 to 3.5 parts by weight based on 100 parts by weight of the above-mentioned basic composition component, the entire body is maintained in a uniform conductivity, shock absorption, electrostatic The present invention relates to a conductive sheet composition and a method for producing the same, wherein the prevention, electromagnetic wave shielding, and electromagnetic wave absorption effects are simultaneously exhibited.

Description

Conductive sheet composition and method for manufacturing the same {Compound of Conductive sheet and method for preparing it}

The present invention relates to a conductive sheet composition and a method for manufacturing the same, more specifically, 60 to 98% by weight of a flat conductive metal powder having a surface ratio of 150 to 450 and 2 to 40% by weight of a crosslinkable non-halogen resin are the basic composition components. It is contained in the present invention, since the emulsifier or surfactant is added to 0.01 to 3.5 parts by weight based on 100 parts by weight of the above-mentioned basic composition component, the entire body is maintained in a uniform conductivity, shock absorption, electrostatic The present invention relates to a conductive sheet composition and a method for producing the same, wherein the prevention, electromagnetic wave shielding, and electromagnetic wave absorption effects are simultaneously exhibited.

 To cope with electromagnetic waves, an invisible disease caused by the development of electronic communication,

Each country regulates electromagnetic waves by competing with human body standards.

As a part of dealing with electromagnetic diseases in Korea, the Ministry of Information and Communication

Specific Absorption Rate (SAR) by applying wave human protection standards:

1.6 W / ㎏) was introduced on April 1, 2002, which required mandatory measurements.

It prohibits the distribution and sale of mobile phones that have not been measured for yield.

 In addition, many scholars have been researched to prove the harmfulness of electromagnetic waves, and many studies have been conducted to suppress the electromagnetic waves in Korea, but the actual products have many problems.

 Currently, domestic electromagnetic wave absorbers or shielding agents are mainly composed of shielding materials in the form of sheet materials for building materials and fiber gaskets for electronic components manufactured by mechanical mixing using metallic materials of carbon or ferrite. . However, the electromagnetic wave absorber or shielding agent is not evenly dispersed because the spherical powder is used without a special treatment process, so that the electrical conductivity is remarkably inferior.

That is, in the case of a metal used as an electromagnetic wave absorber or shielding agent, processing in a flat state rather than using spherical powder not only improves dispersibility, but also improves electrical conductivity and electromagnetic wave absorption rate by increasing the density of the metal powder inside the sheet. Let's do it. However, the technique of processing the metal powder into a flat shape is generally not a popular technique, and the imported metal powder produced in the flat shape has a very high price.

In addition, the manufactured electromagnetic wave absorber or shielding product is manufactured by the shape processing technology using the electromagnetic shielding characteristics of the metallic material itself, the remarkable shielding and electromagnetic wave absorption characteristics of the electromagnetic wave is difficult to expect, and is manufactured by a mechanical mixing process Its physical properties and heat resistance are weak, and its electrical conductivity is low, and the electromagnetic shielding efficiency is lowered. In addition, harmful halogen ions are added to the human body and peripherals, and they are subject to export restrictions.They are not easy to process, they are expensive to manufacture, they lack industrial flexibility and elongation, and they are difficult to control the most important frequencies with electromagnetic wave absorbers. There is.

Currently, products related to electromagnetic waves that are commercially available in Korea are mainly made up of fiber gasket type products, which are already being used gradually in advanced countries. The electromagnetic shielding fiber gasket maintains elasticity by using an insulating sponge, and has a structure in which the outside is coated with a conductive fabric, thereby becoming a conductive material while wrapping the sponge. However, in the fiber gasket, a short of electronic components may be generated due to the silage of the edge portion of the conductive fabric that appears due to the characteristics of the fiber during the cutting process of the electronic product.

The present invention is a cross-linking action of the mixture of the flat conductive metal powder and the above-described metal powder with improved electrical conductivity and improved density by processing into a flat powder having an aspect ratio of 150 to 450, Non-halogen resin, which is harmless to human body and peripheral parts, is contained as basic composition, and it is manufactured by mixing emulsifier or surfactant as additive and specific diluent as needed in certain content ratio. Compared to the gasket coated with a conductive fabric, the entire body maintains uniform conductivity as shown in FIG. 1B, and thus a conductive sheet having excellent impact absorption, antistatic, electromagnetic shielding, and electromagnetic wave absorption effects can be produced. Thus, the present invention has been completed.

The present invention is prepared by mixing a flat conductive metal powder having a surface ratio of 150 to 450 with a non-halogen resin, and an additive, an emulsifier or a surfactant, and optionally a diluent, in a predetermined content ratio. It is an object of the present invention to provide a conductive sheet in which the entire body maintains uniform conductivity, and thus shock absorbing, antistatic, electromagnetic shielding, and electromagnetic wave absorbing effects are exerted simultaneously.

In addition, the present invention is a step of stirring a flat conductive metal powder having a surface ratio of 150 to 450 and a cross-linkable non-halogen resin and additive with a three roll mill, and the mixture in an emulsifier Another object of the present invention is to provide a method for manufacturing a conductive sheet including a step of stirring and laminating the emulsion.

The present invention comprises a basic composition consisting of 60 to 98% by weight of a flat conductive metal powder having a surface ratio of 150 to 450 and 2 to 40% by weight of a crosslinkable non-halogen resin, and an emulsifier or an interface with respect to 100 parts by weight of the basic composition. The electroconductive sheet composition which contains 0.01-3.5 of active agents is characterized by the feature.

In addition, the present invention is a step of stirring a flat conductive metal powder having a surface ratio of 150 to 450, cross-linkable non-halogen resin and emulsifier or surfactant with a three roll mill, stirring the mixture in an emulsifier and the emulsion The manufacturing method of the conductive sheet consisting of three steps of laminating is another feature.

Referring to the present invention in more detail as follows.

The present invention is a cross-linking action between conductive metal powder and metal powder having improved electrical conductivity due to processing into a flat powder having an aspect ratio of 150 to 450, and having high electrical conductivity, which is harmless to human body and peripheral components. Non-halogen resins, emulsifiers or surfactants as additives and optionally diluents are mixed in a certain content ratio to maintain uniform conductivity throughout the body, thereby simultaneously absorbing shock, preventing static electricity, shielding electromagnetic waves, and absorbing electromagnetic waves. It relates to a conductive sheet.

The conductive metal powder used in the present invention includes a conductive single metal, or a conductive alloy powder containing a conductive metal, and a conductive coating metal powder coated with the above conductive metal. When processed, the aspect ratio is relatively large, and thus the dispersibility is improved.

Examples of conductive monometals that can be used in the present invention include nickel (Ni), copper (Cu), silver (Ag), cobalt (Co), stevidium (Sb), aluminum (Al), iron cobalt alloys ( FeCo alloy), iron cobalt vanadium alloy (FeCoV alloy), iron silicon aluminum alloy (FeSiAl alloy) and the like can be included. Conductive metal alloys include, for example, SDST alloys, HIGH-FLUX, nickel-zn ferrites, manganese-zn ferrites, and molally permalloy powders. , MMP) and the like. Coating metal powder coated with conductive metal is, for example, copper (Cu) powder coated with silver (Ag), nickel (Ni) powder coated with silver (Ag), aluminum (Al) coated with silver (Ag) Powder, nickel (Ni) powder coated with aluminum (Al) may be included.

The flat conductive metal powder used in the present invention is produced by using a spherical metal powder in a flat shape without breaking the shape, the method is as follows.

Stainless steel balls (Φ5, Φ10, Φ15, Φ20, Φ25) can be selectively placed on ball mills, attrition mills, or bead mills to provide about two-thirds of the total Jar height. It is manufactured by the method of filling-rotating on the conditions of 12-48 hr and 200-850 rpm, and increasing the aspect ratio of a metal powder by the impact of a ball.

According to the flattening method, the prepared flat metal powder has an area ratio of 150 to 450 with respect to a spherical shape. The flat powder has an effect of increasing the conductivity and packing density of the sheet during sheet production. In the present invention, the aspect ratio is defined as 150 to 450, and when the aspect ratio is less than 150, electromagnetic wave absorption, shielding performance, and electrical conductivity are lowered, and when the surface ratio exceeds 450, a paste using a three roll mill, a sheet manufacturing pretreatment process, is used. In the manufacturing process, the metal is cracked, rather, electromagnetic wave absorption, shielding performance and electrical conductivity is lowered, there is a problem that the basic physical properties of the sheet is inferior. Therefore, it is preferable to use a flat metal powder having a surface ratio of 150 to 450 for superiority of the effect. However, the flat metal powder and other conductive powder are mixed with 5 to 25% by weight of the total amount of the flat metal powder. It has a similar effect.

In addition, in the present invention, a crosslinkable non-halogen resin is used as the basic composition component together with the flat conductive metal powder. It mixes with the flat conductive powder to act as a crosslinking agent and imparts stretchability to the sheet.

As the crosslinkable non-halogen resin that can be used in the present invention, for example, water-soluble urethanes, acrylic emulsions, and mixtures of water-soluble urethanes and acrylic emulsions are selected and used. The non-halogen resins described above have in common crosslinking properties. The water-soluble urethane used as the cross-linkable non-halogen resin is composed of 7 to 12% by weight of isocyanate, 15 to 25% by weight of polyol, 1 to 4% by weight of amine, 55 to 70% by weight of water, and more specifically, water-soluble urethane. 10% by weight silver isocyanate, 20% by weight polyol, 1.6% by amine, 68.4% by weight water. As another non-halogen resin, the acrylic emulsion component is comprised of 14-25 weight% of butyl acrylate, 14-25 weight% of acrylic acid, 0.5-3 weight% of methyl methacrylate, 50-70 weight% of water, etc. The acrylic emulsion consists of 21.0 wt% butyl acrylate, 21.0 wt% acrylic acid, 1.3 wt% methyl methacrylate, and 56.7 wt% water.

In the present invention, 60 to 98% by weight of the flat conductive metal powder having a surface ratio of 150 to 450 and 2 to 40% by weight of the cross-linkable non-halogen resin are used as a basic composition component, wherein the content of the cross-linkable non-halogen resin is used. If the ratio is maintained at less than 2% by weight, there is a problem that the crosslinking role with the metal does not occur.When the ratio is used in excess of 40% by weight, the viscosity increases, resulting in a rough surface of the sheet. This is because there is a disadvantage in that the characteristics, electromagnetic shielding and absorption efficiency are lowered.

In the present invention, an emulsifier or a surfactant is included as an additive. For example, one or two or more selected from oleic acid, ethyl cellulose, tartaric acid and soybean oil are used. The emulsifier or surfactant described above is used within the range of 0.01 to 3.5 parts by weight based on 100 parts by weight of the total amount of the flat metal powder and non-halogen resin mixture contained as basic components.

In addition, in the present invention, a metal paste prepared by mixing a flat metal powder having a surface ratio of 150 to 450 with a cross-linkable non-halogen resin, an emulsifier or a surfactant is dispersed and wetted while stirring in an emulsifier. Diluents can be selected and used for the purpose. As the diluent, for example, methyl ethyl ketone, methyl alcohol, ethyl alcohol, toluene and the like are used, and it is used in the range of 80 to 25 parts by weight based on 100 parts by weight of the basic composition component.

Meanwhile, the present invention includes a method for manufacturing a conductive sheet using the composition described above.

The first step is to weigh 30-90 minutes in a three-roll mill by weighing emulsifying or surfactants with flat conductive metal powders with a surface ratio of 150 to 450, crosslinkable non-halogen resins, and additives, respectively. In the second step, a diluent is added to the metal paste prepared above, followed by stirring for 20 to 180 minutes at 1500 to 3000 rpm in an emulsifier to prepare an emulsion. The third step is to prepare a sheet by laminating the emulsion liquid prepared above with hot air at 65 to 150 ° C. for 5 to 30 minutes.

The conductive sheet of the present invention prepared by the above manufacturing method exhibits shock absorption, antistatic, electromagnetic shielding, and electromagnetic wave absorption at the same time and exhibits uniform conductivity from the entire body.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention.

Examples 1-3

Next, a conductive sheet was prepared under the conditions shown in Table 1 and the contents shown in Table 2. That is, the metal powder, the non-halogen resin, and the additive, an emulsifier or a surfactant, were weighed into the ingredients and contents shown in the following Table 1, respectively. Next, the metal paste was prepared by stirring in a three roll mill under the working conditions of Table 2, and a diluent was added to the prepared metal paste to stir to prepare an emulsion, and the prepared emulsion was laminated to a conductive sheet. Prepared.

Comparative Examples 1 to 4

A conductive sheet was prepared in the same manner as in Examples 1 to 3 under the contents shown in Table 1 and the conditions of Table 2.

On the other hand, the brief description of some of the components used in the Examples and Comparative Examples of the present invention.

1) Silver spherical powder: Silver spherical powder with particle size of 0.8 ~ 4.5 ㎛.

2) Nickel flat powder: A nickel flat powder having a surface ratio of 150 to 450 except for Comparative Example 3 (surface ratio is less than 100) and Comparative Example 4 (surface ratio is greater than 500).

3) Copper spherical powder: Copper powder having a particle size of 1.0 to 10.0 µm.

4) Sandust (SDST) flat powder: A flat powder having an aspect ratio of 150 to 450.

5) Nickel-zinc ferrite powder: Ferrite powder with nickel and zinc in a weight ratio of 30 to 70:70 to 30 and particle size of 0.1 to 1.0 μm.

6) Aluminum flat powder: Aluminum powder with a surface ratio of 150 to 450.

7) Cobalt powder: Cobalt powder whose particle size is 0.5-14.0 micrometers.

8) High-Fluxe Powder: Powder having a particle size of 0.8 to 1.9 mu m.

9) High-fluxe flat powder: Flat powder with a surface ratio of 150-450.

10) Molypermalloy powder (MMP) Flat powder: A flat powder having a surface ratio of 150 to 450.

11) Water-soluble urethane: 10.0 wt% isocyanate, 20.0 wt% polyol, 1.6 wt% amine, 68.4 wt% water.

12) Acrylic emulsion: 21.0 wt% butyl acrylate, 21.0 wt% acrylic acid, 1.3 wt% methyl methacrylate, 56.7 wt% water. division Conductive sheet composition Basic composition component (wt%) Additive (part by weight ^* ) Conductive Metal Powder Non-halogen resin Emulsifier or surfactant diluent Comparative Example 1 100% Silver Spherical Powder (65.0) Water Soluble Urethane (35.0) Tartaric Acid (0.03) + Soybean Oil (0.01) Ethyl Alcohol (40) Comparative Example 2 100% Silver Spherical Powder (65.0) Acrylic Emulsion (35.0) Oleic Acid (0.05) + Soybean Oil (0.02) Methyl Ethyl Ketone (40) Comparative Example 3 100% nickel flat powder with less than 100 aspect ratio (70.0) Acrylic Emulsion (30.0) Oleic acid (0.02) + Soybean oil ( 0.01) Ethyl Alcohol (500) Comparative Example 4 100% Nickel Flat Powder with Aspect Ratio> 500 (70.0) Acrylic Emulsion (30.0) Oleic acid (0.02) + Soybean oil ( 0.01) Ethyl Alcohol (500) Example 1 100% Nickel Flat Powder (70.0) Acrylic Emulsion (30.0) Oleic acid (0.02) + Soybean oil ( 0.01) Ethyl Alcohol (500) Example 2 10% SDST Flat Powder + 10% Nickel-Zinc Ferrite Powder + 75% Aluminum Flat Powder + 5% Cobalt Spherical Powder (75.0) 70% Water Soluble Urethane + 30% Acrylic Emulsion (25.0) Oleic Acid (0.01) + Tartaric Acid (0.01) + Soybean Oil (0.01) + Ethylcellulose (0.01) Methyl Alcohol (45) Example 3 10% High-Fluxe Spherical Powder + 10% MMP Flat Powder + 80% Nickel Flat Powder (75.0) 70% Water Soluble Urethane + 30% Acrylic Emulsion (25.0) Oleic acid (0.02) + tartaric acid (0.02) + soybean oil (0.01) Methyl Alcohol (50) *: Parts by weight based on 100 parts by weight of the basic component division Manufacture conditions Working condition of 3 roll mill step (min) Emulsifier Stirring Step Conditions (rpm, min) Laminating step Working condition (℃, min) Comparative Example 1 15 1500, 30 75, 20 Comparative Example 2 15 1500, 30 90, 17 Comparative Example 3 18 1800, 30 100, 15 Comparative Example 4 18 1800, 30 100, 15 Example 1 18 1800, 30 100, 15 Example 2 15 1800, 20 120, 8 Example 3 15 1800, 20 120, 8

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     The surface resistance and the conduction resistance of the conductive sheet prepared under the conditions described above were measured, respectively, and are shown in Table 3 below.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Surface resistance (Ω / □) 0.05 0.06 0.21 0.14 0.01 0.04 0.00 Current resistance (Ωcm) 0.01 0.01 0.18 0.11 0.00 0.02 0.00

As shown in Table 3, the conductive sheets of Examples 1 to 3 manufactured according to the present invention showed excellent electromagnetic shielding effect with the values of surface resistance and current carrying resistance of 0.1 or less. This is because the present invention is made of a mixture of a flat conductive metal powder having a high electrical conductivity and a non-halogen resin that crosslinks by mixing with the metal powder, thereby maintaining uniform conductivity throughout the body. In addition, when looking at Comparative Example 1 and Comparative Example 2, the non-halogen resin was used to prepare the conductive sheet under the same conditions. Table 3 shows no difference in current resistance, but the water-soluble urethane has a more effective crosslinking effect than the acrylic emulsion. The surface resistance was slightly superior.

And Example 1 using the 100% nickel flat powder having a surface ratio of 150 to 450, Comparative Example 3 is a 100% nickel flat powder having a surface ratio of 100 and Comparative Example 4 being a 100% nickel flat powder having a surface ratio of 500 Looking at it, Example 1 was superior in the conduction resistance and surface resistance compared to Comparative Example 3 and Comparative Example 4. This is because when the aspect ratio is out of the range of 150 to 450, the filling density of the sheet is lowered and the performance of the conductive sheet is lowered. In Examples 2 and 3, a flat metal powder having a surface ratio of 150 to 450 and a spherical metal powder are mixed, and 5 to 25% by weight of the total amount of flat metal powder is replaced with a spherical powder. . In addition, the crosslinkable non-halogen resin is also a conductive sheet prepared by mixing a water-soluble urethane and an acrylic emulsion in a constant ratio. In Table 3, the surface resistance and the conduction resistance were less than 0.1, and there was no difference from the case of using a flat metal powder having a surface ratio of 150 to 450 alone. This shows that even if the flat powder contains about 75 to 95% by weight of the total amount of use, it is possible to manufacture a conductive sheet having uniform conductivity.

In addition, Figure 2 shows the electromagnetic shielding rate using the radio wave reflection of the conductive sheet prepared using Example 3. The shielding rate was 99% at the frequency of 10 MHz to 1 kHz. Figure 3 shows the electromagnetic wave absorption rate of the conductive sheet prepared using Example 2 using the electrical conductivity, the electromagnetic wave absorption rate of 60% was shown at a frequency of 2.45 kHz, and thus the absorbed electromagnetic wave by heat disappears into the present invention The manufactured conductive sheet exhibits shielding and absorption effects of electromagnetic waves at the same time.

Table 4 below shows the basic physical properties of the conductive sheet prepared in Example 1 above.

division unit Test Methods value matter - - Example 1 thickness Μm KSM ISO 2589 100-2000 Hardness - KSB 5527 56 resistance surface Ω / □ JIS K 6911 0.00 Energization ㎝cm 0.00 Electromagnetic shielding efficiency dB ASTM D 4935 68 ± 5 Tensile Strength at Crack Kgf / ㎠ ASTM D 638 150 Prolong upon cracking % ASTM D 638 600 Extension after aging (168hr, 70 ℃) % ASTM D 638 97 Reaction at -30 ℃ low temperature - KSM 6518 No crack Halogen content % IEC 60754-1 none Thermal stability ℃ ASTM D 638 130 Chemical stability - - good density ㎏ / ㎡ ASTM D 638 3.05

According to the present invention, the dispersibility is improved by processing into a flat powder having an aspect ratio of 150 to 450, which is a mixture of a metal powder having a high electrical conductivity and a metal powder. It is made of a mixture of halogen resin, emulsifiers or additives that are additives, so that the whole body maintains uniform conductivity and has the same effect even after bending up and down 360 ° C. It has the effect of simultaneously exerting shock absorption, antistatic, electromagnetic shielding and electromagnetic wave absorption. have

1 shows a conductive sheet of the present invention wherein the entire body is a conductor.

Figure 2 shows the electromagnetic shielding absorption method of the present invention.

3 shows an electromagnetic shielding rate using radio wave reflection.

Figure 4 shows the electromagnetic wave absorption rate using electrical conduction.

Claims (9)

60 to 98% by weight of a flat conductive metal powder having a surface ratio of 150 to 450 and 2 to 40% by weight of a cross-linkable non-halogen resin are contained as a basic composition component, and an emulsifier or an interface with respect to 100 parts by weight of the basic composition components described above. A conductive sheet composition, wherein the active agent is contained in an amount of 0.01 to 3.5 parts by weight. The method of claim 1, wherein the flat conductive metal powder having an aspect ratio of 150 to 450 is a conductive single metal powder, an alloy powder containing the conductive metals, or a metal powder coated with the conductive metal. Electroconductive sheet composition characterized by the above-mentioned. The conductive sheet composition according to claim 1 or 2, wherein a spherical conductive metal powder is alternatively contained within a range of 5 to 25% by weight of the total amount of the flat conductive metal powder. The conductive sheet composition according to claim 1, wherein the non-halogen crosslinkable resin is a water-soluble urethane, an acrylic emulsion, or a mixture of the above-mentioned water-soluble urethane and an acrylic emulsion. The conductive sheet composition according to claim 4, wherein the water-soluble urethane contains 7 to 12 wt% of isocyanate, 15 to 25 wt% of polyol, 1 to 4 wt% of amine, and 55 to 70 wt% of water. The method of claim 4, wherein the acrylic emulsion is 14 to 25% by weight of butyl acrylate, 14 to 25% by weight of acrylic acid, 0.5 to 3% by weight of methyl methacrylate and 50 to 70% by weight of water Conductive sheet composition. The conductive sheet composition of claim 1, wherein the emulsifier or surfactant is selected from oleic acid, ethyl cellulose, tartaric acid and soybean oil. The conductive sheet composition according to claim 1, wherein the composition contains 80 to 25 parts by weight of a diluent selected from methyl ethyl ketone, methyl alcohol, ethyl alcohol and toluene based on 100 parts by weight of the basic composition. 60 to 98% by weight of a flat conductive metal powder having a surface ratio of 150 to 450 and 2 to 40% by weight of a cross-linkable non-halogen resin are contained as a basic composition component, and an emulsifier or an interface with respect to 100 parts by weight of the basic composition components described above. Preparing a metal paste by mixing the respective components in a composition ratio range containing 0.01 to 3.5 parts by weight of the active agent and stirring for 30 to 90 minutes using a 3 roll mill; Preparing the emulsion by stirring the metal paste together with a diluent at 1500 to 3000 rpm for 20 to 180 minutes in an emulsifier; And Laminating the emulsion for 65 to 150 ℃, hot air for 5 to 30 minutes (laminating) to prepare a sheet (sheet) Method for producing a conductive sheet, characterized in that it is included.