KR101597346B1 - Electromagnetic interference shielding film using coating composition with low specific gravity conductive particle - Google Patents

Abstract

The present invention provides an electromagnetic wave shielding film comprising a conductive thermosetting resin layer formed by coating a coating composition containing low specific gravity conductive particles having a specific gravity of 3 or less. The electromagnetic wave shielding film according to an embodiment of the present invention includes a transfer film 10, a first insulating layer 20, a second insulating layer 30, a conductive thermosetting resin layer 40, 50). In the conventional electromagnetic wave shielding film, metal-based conductive particles such as copper particles plated with silver are mainly used for a coating composition for forming a conductive thermosetting resin layer. Such a coating composition has a problem in that since the specific gravity of the metal conductive particles is large, sedimentation occurs during coating in an actual mass production process, and as a result, the electromagnetic shielding performance of the conductive thermosetting resin layer becomes uneven. In contrast, the present invention uses a coating composition containing low specific gravity conductive particles having a specific gravity of 3 or less, so that sedimentation of conductive particles is prevented when coating the conductive thermosetting resin layer, so that even in an actual mass production process, The electromagnetic wave shielding performance of the ground layer becomes uniform.

Description

TECHNICAL FIELD [0001] The present invention relates to an electromagnetic wave shielding film using a coating composition comprising a low specific gravity conductive particle,

The present invention relates to an electromagnetic wave shielding film using an electromagnetic wave shielding coating composition comprising a low specific gravity conductive particle having a specific gravity of 3 or less. More particularly, the present invention relates to an electromagnetic wave shielding film in which a coating agent having a specific gravity of 3 or less and a low specific gravity is used to prepare a coating agent in which precipitation of particles is prevented, and conductive particles are uniformly coated when the coating agent is coated.

In today's information society, radio waves are actively used as information transmission means such as computers, mobile phones, and wireless LANs. On the basis of the development of such electronic technology and semiconductor technology, studies for miniaturization and slimming have been actively pursued as well as improvement of functions of electronic devices and digital devices. For this purpose, circuit density and device integration have been achieved.

Densification of the circuit and integration of the elements increase the possibility of generation and induction of electromagnetic waves and interference with the radiation of noise causes unnecessary external exposure of radio waves, interference between internal circuits, malfunction of the apparatus, There are problems such as harmfulness of the human body caused by propagation disturbance increasing due to high-density information transmission, malfunction of various instruments and information leakage.

As a result, studies have been made to suppress interference caused by the generation of electromagnetic waves (noise) in electronic apparatuses and devices of digital apparatuses. As one example thereof, there has been proposed a technique of shielding the generation of electromagnetic waves or absorbing electromagnetic waves to suppress the interference of electromagnetic waves An electromagnetic wave absorber (shielding member) of a composite magnetic sheet is proposed.

Korean Unexamined Patent Publication No. 2007-0008407 (" performance-enhanced conductive filler and conductive polymer made therefrom ") discloses a composition comprising a conductive metal film formed on a granular carbon-based core such as graphite having a size of 350 to 1000 μm Thereby providing a conductive filler. The conductive filler is used with an elastomer, typically a polymer matrix, such as a silicone elastomer, to form a conductive and EMI shielding composite material. However, since the graphite has a specific gravity of 2 or more and forms a metal film having a larger specific gravity in graphite, there is a limitation in forming a low specific gravity conductive particle having a specific gravity of 3 or less.

Korean Patent No. 10-0597555 (" Electromagnetic wave absorber ") provides an electromagnetic wave absorber having high absorption performance of electromagnetic waves, capable of being thin and lightweight, and capable of exhibiting electromagnetic wave absorption performance over a very wide range. An absorption film 8 made of a mixture of an electromagnetic wave absorbing filler and an electromagnetic wave absorbing polymer material is formed on the peripheral surface of the permeable hole of the porous substrate 3 having a plurality of penetrating holes 2 as shown in Fig. , And the permeability hole (2) is not blocked by the absorbent coating (8) and has air permeability. However, the absorbent filler used in such an electromagnetic wave absorber is not a low specific gravity conductive particle.

Korean Patent Laid-Open Publication No. 2002-0086237 (" synthetic fiber containing hollow spherical particles ") relates to synthetic fibers containing hollow spherical particles, and is made of hollow spheres made of inorganic or organic materials, And the fibers of this patent are light in weight and can effectively solve the problem of heavy wearing comfort which is a disadvantage of functional fibers. However, this patent relates to a synthetic fiber containing hollow spherical particles, more particularly, to provide a fiber with light weight due to the presence of a hollow sphere inside the fiber and to provide various additional functions depending on the constituent material of the hollow sphere The present invention is not directed to low specific gravity conductive particles and electromagnetic wave shielding films using the same.

Japanese Patent Application Laid-Open No. 1998-190280 (" electromagnetic wave absorbing coating material ") provides an electromagnetic wave absorbing material capable of exhibiting electromagnetic wave absorbing performance and capable of forming an electromagnetic wave absorbing layer in spite of being a lightweight material. However, this invention does not relate to an electromagnetic wave shielding film using conductive particles having a low specific gravity.

US 5,968,600 (" EMI / RFI-shielding coating ") relates to an electromagnetic shielding aqueous coating composition comprising an inorganic material such as clay, silica, and particles of copper, silver, nickel, Specific gravity conductive particles are not used.

US Patent No. 6,670,545 (" Conductive coating on a non-conductive flexible substrate ") relates to an electromagnetic shielding film having a conductive coating of electromagnetic shielding on a nonconductive, ductile substrate. However, the conductive material used in the coating liquid is not a low specific gravity conductive particle.

The prior art for the electromagnetic wave shielding film includes Korean Patent No. 10-1095325, Korean Patent No. 10-0896739, Korean Patent No. 10-1046200, Korean Patent Publication No. 10-2008-0019841, Korean Patent No. 10-2012-0137702, Silver, copper, nickel, or the like is used as the conductive particles, or the carbon nanotubes are used as the conductive particles, so that the low specific gravity conductive particles are not used.

As in most prior arts, in the case of coating liquids using metal particles, the metal conductive particles easily settle due to the difference in specific gravity, resulting in nonuniform composition of the coating liquid, resulting in uneven coating and deteriorating the quality of the electromagnetic wave shielding film .

In addition, although it is possible to produce low specific gravity conductive particles by plating metal on the polymer resin particles, there is a problem that the performance of the coating liquid and the electromagnetic wave shielding film using the polymer resin is deteriorated because the metal is not plated well.

Solder Dip / Float test and Hot Oil evaluation are among the items to test the quality of electromagnetic shielding film. The solder dip / float test evaluates the heat resistance of whether the electromagnetic wave shielding film can withstand a high temperature soldering process. After the electromagnetic wave shielding film sample is baked in a drier at 135 ± 5 ° C. for 1 hour Repeat the dipping for 10 seconds in the solder pot at 288 ± 5 ℃ three times. Repeat 3 times for 10 seconds on the solder pot of 260 ± 5 ℃.

In addition, hot oil evaluation measures reliability by repeatedly depositing electromagnetic wave shielding film specimen on high temperature oil and room temperature oil. Baking of electromagnetic wave shielding film specimen is carried out at 135 ± 5 ° C for 1 hour, And then immersed in Hot Oil at 260 ± 5 ° C for 40 seconds and then immersed in Oil at 20 ° C for 4 minutes.

Therefore, when a low-specific gravity conductive particle is prepared by mixing or plating a metal with a polymer resin to prepare a coating liquid composition and using the same to manufacture an electromagnetic wave shielding film, the solder dip / float test and the hot oil evaluation can not withstand high temperatures, do.

KR 10-2007-0008407 (2007.01.17) KR 10-0597555 (2006.06.29) KR 10-2002-0086237 (November 11, 2002) JP 1998-190280 (Jul. 21, 1998) US 5,968,600 (Oct. 19, 1999) US 6,670,545 (Dec. 30, 2003)

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electromagnetic shielding coating composition containing particles of low specific gravity and preventing precipitation of particles, and using the same, Shielding film. That is, by forming a conductive thermosetting resin layer in which conductive particles are evenly coated even in the case of mass production, an electromagnetic shielding film with uniform electromagnetic shielding performance is provided.

And when the polymer resin is used as a constituent component of the conductive particles, the polymer resin is crosslinked to improve the thermal stability, thereby providing an electromagnetic wave shielding film having heat resistance even at high temperatures.

In addition, when metal particles are coated on the polymer resin particles to produce low specific gravity conductive particles, the problem of poor plating is solved and the performance of the electromagnetic wave shielding film using the particles is improved.

  In the present invention, the low specific gravity conductive particles can be divided into low specific gravity hollow conductive particles and low specific gravity non-solid conductive particles.

The non-hollow conductive particles have a specific gravity of 2 or less and a low specific gravity, for example, even when a polymer resin having a specific gravity of 1 is mixed with a conductive carbon having a specific gravity of 2 at an arbitrary weight ratio. As another example, when a polymer resin having a specific gravity of 1, a conductive carbon having a specific gravity of 2, and a metal powder having a specific gravity of 9 are mixed, as shown in Tables 1 and 2, a conductive carbon 40 To 55% by weight and the metal powder in an amount of 5 to 20% by weight, the mixture has a low specific gravity of 3 or less. Further, when 20 to 35% by weight of the conductive carbon and 5 to 20% by weight of the metal powder are mixed in 60% by weight of the polymer resin, the mixture has a low specific gravity of 3 or less. By mixing in various mixing ratios as described above, low specific gravity conductive particles having a specific gravity of 3 or less can be produced.

However, the electromagnetic wave shielding film using the polymer resin as a constituent component of the conductive particles causes defects in the heat resistance and reliability test performed at 288 占 폚 and 260 占 5 占 폚. In order to solve such a problem, it is preferable in the present invention to improve the heat resistance by adding a cross-linking agent and crosslinking it.

The non-hollow conductive particles prepared as described above may be plated with a metal or coated with a conductive polymer to further improve conductivity. In this case, silica, glass powder, and metal powder are partially exposed on the particle surface by mixing silica resin, glass powder, and metal powder into the polymer resin, and when the metal is plated, this portion becomes a growth point of the plating Plating becomes good.

Another method for improving the conductivity of non-hollow conductive particles is to coat (coat) fine powder such as carbon powder or metal powder with good conductivity.

Another method for improving the conductivity of non-hollow conductive particles is to coat the surfaces of the conductive particles with fine silica, glass powder, metal powder or the like so that the properties of the particle surface are improved by plating There is a method of plating with metal after reforming. This method will be described in detail as follows.

Since the specific gravity of the non-hollow polymer resin particles is 1 to less than 1, it is possible to produce non-hollow conductive particles having a low specific gravity by plating them with a metal.

However, the polymer particles have characteristics that metals such as copper and silver are not easily plated. Therefore, the plating is uneven and the electric conductivity is lowered, and the performance of the coating solution and the electromagnetic wave shielding film using the same is lowered. In order to solve this instability of plating, various methods have been experimented and it has been found that silica, glass, and metal are more plated than polymer resin. Silica, and metal are adhered to the surface of the polymer resin particles, the surface characteristics of the particles become the same as those of glass, silica, and metal, and thus plating can be easily performed. The present invention has been completed intensively.

When a fine powder having a diameter which is one fifth to one-tenth of a diameter of a low specific gravity particle to be produced is coated (coated) on the surface of the low specific gravity particle, the specific gravity of the low specific gravity particle is maintained The surface properties change to the properties of the coated powder. When the multi-component composite particles having the surface characteristics changed by plating are plated with a metal such as copper or silver, the electroplating is satisfactorily performed, and the performance of the electromagnetic wave shielding film manufactured by using the coating liquid containing the same is greatly improved do.

The hollow conductive particles include, for example, polymeric resin hollow particles, organic hollow particles other than the polymer resin, inorganic hollow particles, carbon hollow particles, metal hollow particles, and mixtures thereof. Depending on the number of hollows inside the particle, it can be divided into single hollow particles and multiple hollow particles. Any of them can be used.

When a coating composition is prepared using carbon hollow particles or hollow metal particles having a high specific gravity and a low specific gravity, the precipitation of conductive particles is prevented, and thus the electromagnetic wave shielding film using the coating composition has uniform and good performance.

Hollow conductive particles in which polymeric resin-based hollow conductive particles or a polymer resin is mixed with a conductive material such as a carbon-based material or a metal powder have poor heat resistance, so that a crosslinking agent is applied to the surface of the particles, Can be improved.

The hollow conductive particles may be plated with a metal or coated with a conductive polymer to further improve the conductivity. In the case of using a polymer resin, silica, glass powder, metal powder, etc. are mixed with the polymer resin to prepare hollow conductive particles, and silica, glass powder, metal powder, and the like are partially exposed on the particle surface. Becomes a growth point of the plating, and the plating becomes good.

Another method for improving the conductivity of the hollow conductive particles is to coat (coat) fine powder such as carbon powder or metal powder with good conductivity.

Another method for improving the conductivity of the hollow conductive particles is to coat the surface of the conductive particles with fine silica, glass powder, metal powder or the like to modify the properties of the particle surface to a property of good plating Thereafter, there is a method of plating with metal. This method is as described in detail in the case of non-perforated conductive particles.

It is also preferable to use any one or more selected from the above-described organic conductive powder, organic material, organic hollow particle, and electroconductive polymer having conjugated structure as the material constituting the polymer resin, polypyrrole, polythiophene, polyaniline and derivatives thereof Do.

A coating composition is prepared by mixing a thermosetting binder resin, a solvent, a curing agent, a surfactant, and the like to the conductive particles having a low specific gravity prepared as described above. Since this coating uses low specific gravity conductive particles, precipitation does not occur for a long period of time.

After forming a first insulating layer and a second insulating layer on a transfer film, the above-mentioned coating composition is coated to form a conductive thermosetting resin layer, and a protective film is attached to produce an electromagnetic wave shielding film.

One or more metal thin film layers such as silver and copper may be added between the second insulating layer and the conductive thermosetting resin layer of the electromagnetic wave shielding film. The metal thin film layer can be formed by sputtering, vacuum deposition, metal spraying, ion plating, or the like.

The metallic thin film layer can be sintered by generating a high temperature in a short time by irradiating a white flash with a xenon lamp to the metal thin film layer.

When the metal thin film layer is sintered, the density of the metal thin film layer increases and the defects such as pinholes are removed, thereby increasing the conductivity and improving the performance of the electromagnetic wave shielding film.

The conductive thermosetting resin layer of the electromagnetic wave shielding film may be sintered in the same manner as described above. When the thermosetting resin layer is sintered, the density of the thermosetting resin layer is increased to increase the conductivity, thereby improving the performance of the electromagnetic shielding film.

According to the present invention, since the coating composition containing a low specific gravity conductive particle having a specific gravity of 3 or less prevents the deposition of conductive particles over a long period of time, the coating can be uniformly performed even in an actual mass production process. As a result, A certain electromagnetic wave shielding film can be produced.

In the case of conductive particles comprising a polymer resin as a constituent, an electromagnetic wave shielding film having improved heat resistance can be produced by crosslinking using a crosslinking agent.

Further, in the case of producing a low specific gravity conductive particle by plating a metal on the polymer resin particle, the surface of the particle is coated with a material that can be plated, thereby improving the plating and improving the performance of the electromagnetic wave shielding film .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a basic structural view of an electromagnetic wave shielding film of the present invention. FIG.
2 is a view showing a conventional electromagnetic wave shielding film.
Figure 3 shows the chemical structure of alpha-cyclodextrin used in the Examples.

Hereinafter, the present invention will be described in detail.

1. The electromagnetic wave shielding film of the present invention basically comprises a transfer film 10, a first insulating layer 20, a second insulating layer 30, a conductive thermosetting resin layer 40, And a protective film 50.

It is important that the transfer film 10 has a smooth coating property of the first insulating layer 20 and a releasability of the conductive thermosetting resin layer after heat curing. It is preferable to apply a release coating to a matte PET (polyethylene terephthalate) film. Polyphenylene sulfide (PPS), polyimide film and the like can also be used.

The first insulating layer 20 is required to have insulating properties and to further protect against damage such as solvent resistance, chemical resistance and scratches. The first insulating layer 20 is also applicable to a transparent coating material to which the particles are not applied, provided that compatibility with the second insulating layer 30 is not a problem. Since the second insulating layer 30 must have high adhesion with the first insulating layer 20, it is most preferable to apply the same type of resin. In view of such properties, polyester, melamine and the like are preferable as the binder resin used for the first insulating layer 20. [

The conductive thermosetting resin layer (40) should exhibit a high adhesive force with the base material, conductivity and electromagnetic shielding performance after being pressurized at high temperature. The thermosetting resin is preferably an epoxy resin, a polyester, a melamine, a polyamide resin, or the like.

Methods for coating the insulating layers 10 and 20 and the conductive thermosetting resin layer 40 include comma coating, gravure coating, slot die coating, microgravure coating, and spray coating. And then dried at 50 to 120 DEG C for 5 to 15 minutes.

The protective film 50 for protecting the conductive thermosetting resin layer 40 may be a general silicone protective film. The protective film 50 protects the conductive inorganic material resin layer in which the conductive inorganic material is mixed and prevents the oxidation of the conductive inorganic material. Even if the electromagnetic shielding film is not used, the protective film 50 can be reworked ).

2. In the present invention, the low specific gravity conductive particles can be divided into low specific gravity hollow conductive particles and low specific gravity non-solid conductive particles.

The non-hollow conductive particles have a specific gravity of 2 or less and a low specific gravity, for example, even when a polymer resin having a specific gravity of 1 is mixed with a conductive carbon having a specific gravity of 2 at an arbitrary weight ratio. As another example, when a polymer resin having a specific gravity of 1, a conductive carbon having a specific gravity of 2, and a metal powder having a specific gravity of 9 are mixed, as shown in Tables 1 and 2, the conductive carbon 40 to 55 By weight and 5 to 20% by weight of the metal powder are mixed, the mixture has a low specific gravity of 3 or less. Further, when 20 to 35% by weight of the conductive carbon and 5 to 20% by weight of the metal powder are mixed in 60% by weight of the polymer resin, the mixture has a low specific gravity of 3 or less. By mixing in various mixing ratios as described above, low specific gravity conductive particles having a specific gravity of 3 or less can be produced.

Specific gravity of mixture according to mixing ratio of polymer resin (specific gravity 1), conductive carbon (specific gravity 2) and metal powder (specific gravity 9) 1 Polymer resin content
(weight%) Conductive carbon content
(weight%) Metal content
(weight%) Specific gravity of mixture 40 55 5 1.95 20 10 2.3 45 15 2.65 40 20 3 45 50 5 1.9 45 10 2.25 40 15 2.6 35 20 2.95

Specific gravity of mixture according to mixing ratio of polymer resin (specific gravity 1), conductive carbon (specific gravity 2) and metal powder (specific gravity 9) 2 Polymer resin content
(weight%) Conductive carbon content
(weight%) Metal content
(weight%) Specific gravity of mixture 50 45 5 1.85 40 10 2.2 35 15 2.55 30 20 2.9 55 40 5 1.8 35 10 2.15 30 15 2.5 25 20 2.85 60 35 5 1.75 30 10 2.1 25 15 2.45 20 20 2.8

The non-hollow conductive particles may be selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl chloride, poly methyl meta acrylate, polybutadiene, And can be produced by using any one or two or more polymer resins selected from copolymers. In order to impart conductivity to such a polymer resin, a vapor-grown carbon fiber (VGCF), a conductive carbon black, a ketjen black, an acetylene black , a furnace black, a thermal black a conductive black material, a thermal black, a channel black, a carbon fiber, a carbon nanotube, a graphite, a graphene, a conductive polymer, and a metal powder.

The mixing method may be a heating melt mixing method at 110 to 200 캜, a method of dissolving and mixing in a solvent, a method of mixing these two methods, and the like. The mixer may be a conventional extruder, a Brabender Plasticorder, a Banbary Mixer, a Kneader, a Roll Mill, or the like.

The content of the polymer resin is suitably from 20 to 70% by weight, particularly preferably from 40 to 60% by weight. When the content of the polymer resin is less than 20% by weight, the binding force of the particles is lowered, and when it exceeds 70% by weight, the conductivity is lowered. The content of the conductive material is suitably from 5 to 80% by weight, particularly preferably from 10 to 70% by weight. When the content of the conductive substance is less than 5% by weight, the conductivity is lowered, and when it exceeds 80% by weight, the bonding force is decreased.

In order to improve the heat resistance, the conductive particles thus produced are inferior in heat resistance. In order to improve the heat resistance, the dicumyl peroxide, benzoyl peroxide, lauryl peroxide, tert-butyl cumyl peroxide butyl cumyl peroxide, di (tert-butyl peroxy isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane , 5-dimethyl-2,5-di (tert-butyl peroxy) hexane and di-tert-butyl peroxide are mixed, and at least the decomposition temperature Followed by crosslinking.

The crosslinking agent may be used in an amount of 0.5 to 5% by weight, preferably 1 to 3% by weight. When the content of the crosslinking agent is less than 0.5% by weight, the crosslinking property is not exhibited, and when it exceeds 5% by weight, workability is deteriorated. The cross-linking agent may be added at the beginning of the mixing, or may be added at the middle or late of the mixing. The cross-linking process used to prepare the crosslinked polymer for imparting heat resistance and suppressing the deformation of the polymer at high temperatures includes a process using various peroxides, a Sioplas process using silane, a process using vinylsilane Monosil processes are all possible. The silane includes vinyl trichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrialkoxysilane, aminosilane, meerocapthosilane, and acetoxysilane.

3. In the above configuration, non-hollow conductive particles can be plated with metal or coated with a conductive polymer to further improve conductivity. In this case, silica, glass powder, and metal powder are partially exposed on the particle surface by mixing silica resin, glass powder, and metal powder into the polymer resin, and when the metal is plated, this portion becomes a growth point of the plating Plating becomes good.

Specifically, any one selected from copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, titanium, molybdenum, antimony, tantalum, vanadium, palladium, A plurality of metals may be plated by a plating method to be described later to improve the conductivity of the conductive particles.

In addition, the conductivity of the conductive particles can be improved by coating one or more conductive polymers selected from polypyrrole, polythiophene, polyaniline and derivatives thereof to the non-hollow conductive particles. When a conductive polymer such as polyaniline is dissolved in chloroform or m-cresol and mixed with particles in a Henschel mixer while spraying, the conductive polymer is coated on the surface of the particles.

Electroplating and electroless plating are available as plating methods. Either method may be used. Hereinafter, the electroless plating method will be described in detail. Electroless plating is used in various fields in terms of its performance. The electroless plating can easily deposit the plating by performing the catalytic treatment on the material which can not be energized. This makes it possible to metallize the surface even in the absence of electrical conductivity, and thus it is widely used for the metallization of plastics and the manufacture of printed wiring boards. The catalyst used in the catalytic treatment is generally palladium. The catalyst solution is palladium chloride (PdCl _2), sulfuric acid, palladium (PdSO _4), nickel chloride (NiCl _2), zinc chloride (ZnCl _2), silver chloride (AgCl), copper chloride (CuCl _2), iron chloride (FeCl _2), chloride It is preferable that at least one metal material selected from the group consisting of tin (SnCl ₂ ), antimony chloride (SbCl ₃ ) and indium chloride (InCl ₃ ) is dissolved in an acid solution which is an aqueous solution of hydrochloric acid, sulfuric acid or the like.

The amount of the electroless copper plating is 5 to 50 g / l of ethylene dinitrile-tetra-2-propanol (EDTP), 10 to 20 g / l of copper sulfate (II) pentahydrate (CuSO ₄ .5H ₂ O) 15 g / l of sodium hydroxide (NaOH) and 2.5 to 10 g / l of formaldehyde (HCHO) stabilizer.

The silver plating solution contains silver nitrate as a metal salt and ammonium hypophosphite as a reducing agent. The concentration of silver nitrate is preferably 0.5 to 5 g / l, and the concentration of ammonium hypophosphite is preferably 5 to 30 g / l. This is because, if the concentration of silver nitrate is less than the above range, the plating rate is lowered. If the concentration exceeds the above range, the plating rate is increased but the plating liquid is likely to decompose. Similarly, when the concentration of ammonium hypophosphite is less than 5 g / ℓ, the plating rate decreases and the productivity decreases. When the concentration exceeds 30 g / ℓ, the plating rate increases but the stability of the solution deteriorates and the plating solution decomposes This is because there are easy disadvantages.

The electroless silver plating solution further contains ammonia water as a complexing agent, and one of ethylenediamine and ethylenediaminetetraacetic acid (EDTA) is used as a complexing agent.

4. Another method for improving the conductivity of non-hollow conductive particles is to coat (coat) fine powder such as carbon powder or metal powder with good conductivity.

Specifically, in the case of an organic powder (powder), an inorganic powder, a carbon powder, and a metal powder having an average diameter of the powder particles of 1/5 to 1/10000 of the average diameter of the non-hollow conductive particles And then coating (coating) the selected one kind or plural kinds of powders on the surface of the conductive particles. The diameter of the fine powder coated on the surface of the particles is preferably 1/5 to 1/10000 of the diameter of the non-hollow conductive (conductive) particles. If it is less than this range, it becomes too fine to reduce workability. If it is larger than this range, coating becomes difficult. Powders having good conductivity and low specific gravity are preferable, and examples thereof include conductive polymer powders and conductive carbon. Metal powders are also useful because they have high specific gravity but good conductivity. Examples of the apparatus for coating the powder include a ribbon mixer, a V-mixer, a double cone mixer, a terblanc mixer, a Henschel mixer, and a powder composite machine. In this device, non-hollow conductive particles and fine powder are mixed and mixed to form a fine powder. The heat is generated by the heat generated by the mixing and bonding of a small amount of tacky or adhesive material while spraying. have.

5. A process for producing a conductive particle as described in any one of (1) to (5) above, wherein the coated (non-conductive) conductive particles are selected from the group consisting of copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, The conductivity of the conductive particles can be further improved by coating one or more selected from antimony, tantalum, vanadium, palladium, bismuth, and conductive polymer. The method is the same as described above.

6. The hollow particles used in the present invention may be hollow polymer particles including polymeric resin hollow particles, polymeric resin materials, organic materials, inorganic materials, carbon materials and metal materials. Of course, organic hollow particles, inorganic hollow particles, and carbon-based hollow particles may be used instead of the mixed material. Hollow particles having good conductivity and low specific gravity are preferable. From this point of view, conductive polymer hollow particles are preferable. The hollow particles may be produced by a known technique. For example, "Techniques for Manufacturing Hollow Inorganic Nanoparticles Using Polymer Nanotubes" (Polymer Science and Technology, Vol. 18, No. 1, Feb. 2007, p. 39), hollow particles of calcium carbonate were prepared by W / O emulsion method, And a method of producing by a bubble template method. Hollow glass beads, hollow inorganic fillers, short hollow resin fine particles, multi-pore resin fine particles sold by Sekisui Chemical Co., Ltd. (Japan), etc., which are commercially available from Seocye CMT (Korea) .

7. The hollow particles comprising the polymer resin are prepared by mixing the cross-linking agent at the time of production and heating the cross-linking agent by heating to a temperature not lower than the decomposition temperature of the cross-linking agent, or by applying the cross-linking agent to the surface of the hollow particles, Heat resistance should be improved. The kind and amount of the crosslinking agent used are as described above.

8. A process for producing a conductive particle as described in any one of the above (1) to (5), wherein the hollow conductive conductive particles are coated with a metal selected from the group consisting of copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, , Vanadium, palladium, and bismuth may be plated by the above-described plating method to improve the conductivity of the conductive particles. It is also possible to coat the hollow conductive conductive particles with one or a plurality of conductive polymers selected from polypyrrole, polythiophene, polyaniline and derivatives thereof by the aforementioned method to improve the conductivity of the conductive particles have.

9. Hollow Conductivity Another way of improving the conductivity of the particles is to increase the conductivity of the organic particles in which the average diameter of the powder particles is one fifth to one-tenth of the average diameter of the hollow conductive particles There is a method in which one or more kinds of powders selected from powders, inorganic powders, carbon powders and metal powders are coated on the surface of the conductive particles by the above-mentioned method.

10. Since the organic powder, the inorganic powder, the carbon powder, and the metal powder have different physical properties (specific gravity, particle size, particle shape, electrical conductivity, plating characteristics, etc.) The particle size, the electric conductivity, the plating property, and the like can be suitably adjusted. Fine powder, fine powder, fine powder, fine powder, fine powder, fine powder, fine powder, fine powder, fine powder, fine powder, fine powder, Inorganic powder-carbon powder, and the like, it is possible to produce a multi-component composite powder having desired properties.

The multi-component composite powder will be described in more detail. The hollow polymer particles have a drawback that when coated with a specific gravity of 1 or less, they become low specific gravity conductive particles, but they are not plated more easily than glass beads, silica, and metal particles. Therefore, the conductivity of the conductive particles is lowered and the performance of the electromagnetic wave shielding film using the conductive particles is deteriorated. In order to solve such a problem, for example, if the hollow polymer particles having a size of 3 to 5 탆 are subjected to a composite treatment with nano-sized silica particles to firmly coat the silica particles on the surface of the hollow polymer particles, And the performance of the electromagnetic wave shielding film using the same is improved.

Expansion graphite has a disadvantage of low specific gravity but poor conductivity. It is possible to produce a multicomponent composite powder coated on the surface of expanded graphite by using a thermoplastic polymer resin powder and copper powder having a diameter of about 1/100 of the diameter of expanded graphite and have a low specific gravity and good electrical conductivity and good plating Hollow hollow conductive particles can be produced. Therefore, the performance of the electromagnetic wave shielding film using the conductive particles is improved.

Conventional studies have produced a coating agent using conductive particles plated with single-component powder particles or mixed conductive particles having different shapes such as spherical conductive particles and acicular conductive particles. On the other hand, in the present invention, the multi-component composite powder particles are prepared and then plated to prepare low specific gravity hollow conductive particles, and a coating agent and an electromagnetic wave shielding film are prepared using the hollow conductive particles.

The diameter of the fine powder coated on the surface of the hollow particles is preferably one fifth to one-tenth of the diameter of the hollow particles. If it is less than this range, it becomes too fine to reduce workability. If it is larger than this range, coating becomes difficult. Examples of the fine powder to be coated include organic powder (powder), inorganic powder, carbon powder, metal powder and the like. A powder having a good conductivity and a low specific gravity is preferable, for example, a conductive polymer powder. Metal powders are also useful because they have high specific gravity but good conductivity.

Examples of the apparatus for producing a multicomponent composite powder include a ribbon mixer, a V-mixer, a double cone mixer, a terblanc mixer, a Henschel mixer, and a powder composite machine. In this apparatus, fine powder and hollow conductive particles are mixed, The composite powder can be produced by a method such as spraying of a viscous material, mixing of an adhesive material, and the like.

It is also preferable to use any one or more selected from the above-described organic conductive powder, organic material, organic hollow particle, and electroconductive polymer having conjugated structure as the material constituting the polymer resin, polypyrrole, polythiophene, polyaniline and derivatives thereof Do.

11. The coating composition contains, as an essential component, a thermosetting binder resin, a solvent, a low specific gravity conductive particle of the present invention, a curing agent and a surfactant, and optionally contains an antioxidant as a constituent.

The thermosetting binder resin is classified into a condensation polymerization type (condensation polymerization type) and an addition polymerization type. The condensation type includes phenol resin, urea resin, and melamine resin. The addition polymerization type includes epoxy resin and polyester resin. The amount to be used is preferably 0.3 to 50% by weight. When the amount is less than 0.3%, the bonding force is insufficient and when it exceeds 50% by weight, the conductivity is lowered.

Various organic solvents can be used as the solvent, but ethanol is preferable considering the health and environment of the worker. The amount is preferably 10 to 60% by weight. When the amount is less than 10%, the viscosity of the coating agent is too high and the workability is deteriorated. When the amount is more than 60% by weight, the physical properties such as conductivity and bonding force are lowered.

It is preferable to use 30 to 70 wt% of low specific gravity conductive particles having a specific gravity of 3 or less as the conductive particles of the present invention. When the content is less than 30 wt%, the conductivity is deteriorated. When the content is more than 70 wt% .

As the hardening agent, hexamethylenetetramine, amines, polyamides, acid anhydrides, boron trifluoride and the like can be used, and the amount is preferably 0.1 to 7% by weight. When the amount is less than 0.1%, the curing action is insufficient, and when it exceeds 7% by weight, physical properties such as flex resistance of the film are lowered.

As the surfactant, it is preferable to use a nonionic surfactant, but an anionic surfactant, a cationic surfactant, and an amphoteric surfactant can also be used. The amount to be used is preferably 0.1 to 3% by weight. When the amount is less than 0.1%, the dispersing action is insufficient, and when the amount is more than 3% by weight, the dispersing effect does not increase any more.

Examples of the antioxidant include 1-octanethiol, butylated hydroxytoluene (BHT), dibutyl hydroxytoluene (DHT), bridhydroxyarisol (BHA) Benzo triasol, toril triasol, cyclic amines and the like can be used. The amount to be used is preferably 0.1 to 3% by weight. If the amount is less than 0.1%, the antioxidant effect is insignificant. If the amount is more than 3% by weight, the antioxidant effect does not increase any more.

The manufacturing procedure of the coating agent is as follows. After the surfactant is mixed with the solvent and the conductive particles are dispersed, the binder resin is added and mixed. Then, the hardener and, if necessary, the antioxidant are added and mixed.

12. A metal thin film layer may be further formed on the second insulating layer by sputtering, vacuum deposition, metal spraying, ion plating, or the like. When such a metal thin film layer is further provided, the electric conductivity is increased to improve the electromagnetic shielding performance.

13. Further, it is also possible to further perform sintering by irradiating a metal thin film layer of the electromagnetic wave shielding film with a white flash (xenon lamp) by a xenon lamp. When the sintering is performed by flash light, only the surface of the metal thin film layer is instantaneously heated to sinter and the underlying insulating layer and the like are not damaged. Since the sintered metal thin film layer becomes dense and has a high density, the electric conductivity increases, and as a result, the electromagnetic shielding performance is improved.

14. Further, the conductive thermosetting resin layer of the electromagnetic wave shielding film may be further sintered in the same manner as described above. When flash light is sintered, only the surface of the conductive thermosetting resin layer is instantaneously heated to be sintered. The structure of the sintered conductive thermosetting resin layer becomes dense and the density becomes high, so that the electric conductivity increases, and as a result, the electromagnetic shielding performance is improved.

A device for irradiating a white flash with a xenon lamp is a flash lamp annealing device (model FLA-100AS) manufactured by Dresden Thin Film Technology, Germany. As a method of sintering by irradiating a white flash with a xenon lamp, high-temperature heat is generated and sintered in a short period of microseconds to milliseconds using a high-voltage pulse power supply .

Hereinafter, the present invention will be described in detail by way of examples, but it should not be construed as being limited thereto.

1. Example 1 < Production of non-pore-forming conductive particles 1 >

(Weight average molecular weight: 70,000) as a polymer binder, vapor-grown carbon fiber (VGCF) and copper powder (average particle size: 0.5 m) as a conductive agent, and cumyl hydroperoxide as a crosslinking agent at a weight ratio of 45: 43: 10: 2 ratio. The high density polyethylene is fed into a twin-screw extruder and the vapor-grown carbon fiber (VGCF) is divided into 10 parts in a state where the polymer is melted at a temperature range (120-180 ° C) at which the polymer is melted at 170 ° C Uniformly mixed, and copper powder was added thereto to uniformly mix. Thereafter, the cross-linking agent was added and mixed, and then the mixture was extruded through an extruder die heated at 250 ° C to form a sheet having a thickness of 1 mm and cooled. When the molten polymer passes through an extruder die, cumyl hydroperoxide, which is pyrolyzed, generates radicals, which causes a crosslinking reaction with the melted pulley ethylene main chain. When the extruder die comes out, . The cooled sheet-shaped extrudate was coarsely pulverized by a roll mill and then finely pulverized by a dry colloid mill to prepare non-rigid conductive particles having an average particle size of 7 탆. The density of the specific gravity conductive particles produced was 2.2 g / cm &lt; ^{3 &} gt ;.

2. Example 2 < Production of non-pore-forming conductive particles 2 >

Polyaniline, a conductive polymer, was dissolved in chloroform to prepare a 20 wt% solution. 400 g of the conductive particles of Example 1 were placed in a Henschel mixer and the polyaniline solution was mixed while spraying. The mixture was sprayed with 20 g of the polyaniline solution at a linear speed of 40 m / s, and the mixture was stirred for 1 minute and for 1 minute, and 10 times, polyaniline was coated on the surface of the conductive particles. At this time, the solvent chloroform was evaporated by the heat generated by the stirring blades rotating at a high speed. The density of the specific gravity conductive particles produced was 2.1 g / cm &lt; ^{3 &} gt ;.

3. Example 3 < Production of Non-Heavy Boundary Conductive Particles 3 >

Copper powder (CUSP70, average particle size 7.0 mu m) of Joinm Co., Ltd. (Korea) was finely pulverized to adjust the average particle size to 0.1 mu m. 20 g of the above copper powder and 2 g of polyethylene (LDPE) powder having an average particle size of 0.5 탆 and a melting point of 105 캜 to 115 캜 were placed in 200 g of the non-pore-forming conductive particles of Example 1 at a linear speed of 40 m / s using a Henschel mixer The 2-minute mixing and the 1-minute stop were repeated 5 times to cover the non-bare conductive particles of Example 1 with copper and polyethylene. At this time, the polyethylene (LDPE) powder was melted by the heat generated as the stirring blade rotated at a high speed, and was coated on the particle surface together with the copper powder. The density of the specific gravity conductive particles produced was 2.8 g / cm &lt; ^{3 &} gt ;.

4. Example 4 < Production of non-pore-forming conductive particles 4 >

Silver nitrate was dissolved in distilled water to prepare an aqueous solution having a silver nitrate concentration of 2.0 g / l. Ammonia water and ethylenediamine were added as a complexing agent to the aqueous solution at 120 ml / L and 5.2 g / L, respectively. Ammonium hypophosphite was dissolved in distilled water to prepare a reducing agent aqueous solution having a concentration of 15 g / l. The aqueous ammonium phosphite solution was adjusted to pH 10.5 by adding 10 wt% aqueous solution of sodium hydroxide.

The prepared silver salt aqueous solution and the reducing agent aqueous solution were mixed to prepare a plating solution. The non-hollow conductive particles of Example 3 were placed in a plating solution and stirred at room temperature for 30 minutes to perform plating. After plating, it was filtered, washed three times with distilled water, and then dried. The density of the specific gravity conductive particles produced was 2.9 g / cm &lt; ^{3 &} gt ;.

5. Example 5 < Production of Hollow Conductive Particles 1 >

700 g of HYDRO BG100 (ethylene oxide / propylene oxide block copolymer) and 300 g of alpha -cyclodextrin were added to 4000 g of distilled water and stirred at room temperature for 15 hours to obtain alpha-cyclodextrin (HYDRO BG100) α-cyclodextrin) was inserted into the microcapsules. The hollow carbon particles were pyrolyzed in an electric furnace at 900 ° C under a nitrogen atmosphere. The average particle size of the hollow conductive particles produced was 1.7 mu m and the density was 0.3 g / cm &lt; ^{3 &} gt ;.

6. Example 6 < Production of Hollow Conductive Particles 2 >

60 ml of polydiallylammonium chloride and 3 g of gelatin were completely dissolved in 1800 ml of distilled water as a suspension stabilizer and then placed in a 3 liter capacity five-necked reactor equipped with a stirrer, a condenser, a nitrogen supply line and a temperature controller. Dissolved oxygen was removed for more than 1 hour. Divinylbenzene and styrene were washed three times with 5 wt% sodium hydroxide solution and water, respectively, to remove the polymerization inhibitor. 15 ml of the washed divinylbenzene and 185 ml of styrene were placed in an Erlenmeyer flask, 1.2 g of AIBN (Azobisisobutyronitrile) was added as an initiator, and the mixture was dissolved. To this monomer mixture, copper powder (CUSP70, average particle size 7.0 탆) Finely pulverized, and adjusted to have an average particle size of 0.1 탆, were put and mixed.

The mixture was placed in a five-necked reactor, suspended at 40 DEG C for 30 minutes, then elevated by 1 DEG C / minute and raised to 80 DEG C. [ After reacting at 80 ° C for 24 hours, the synthesized spherical polymer was filtered and washed and dried in a vacuum oven at 100 ° C for 24 hours to prepare polymer hollow particles. 2 g of cumyl hydroperoxide as a cross-linking agent was added and uniformly mixed to coat the surface of the particles. The particles were then raised at a rate of 5 ° C / minute, and the temperature was raised to 200 ° C to crosslink the particle surfaces. The average particle size of the produced hollow conductive particles was 8.2 탆, and the density was 2.6 g / cm ³ .

7. Example 7 < Production of Hollow Conductive Particles 3 >

The hollow conductive particles of Example 6 were subjected to silver plating in the same manner as in Example 4. The density of the produced hollow conductive particles was 2.8 g / cm &lt; ^{3 &} gt ;.

8. Example 8 < Production of Hollow Conductive Particles 4 >

Expanded graphite is one of the carbon-based hollow particles with voids inside. Expansion graphite (EP-100, density 0.3 g / cm ³ , average particle size 100 μm) of Samjung Co., Ltd. was milled with a colloid mill to adjust the average particle size to 4 μm. Copper powder (CUSP70, average particle size 7.0 mu m) of Join M. Co. was finely pulverized to adjust the average particle size to 0.1 mu m. 50 g of the above copper powder and 10 g of polyaniline powder (average particle size: 0.5 m) as a conductive polymer were added to 250 g of the expanded graphite and mixed for 2 minutes at a linear speed of 40 m / s and 5 minutes for 1 minute with a Henschel mixer Copper and polyaniline were repeatedly coated on hollow expanded graphite particles. The density of the produced hollow conductive particles was 1.7 g / cm &lt; ^{3 &} gt ;.

9. Example 9 < Production of Hollow Conductive Particles 5 >

50 g of nanosilica (HS-40) manufactured by DuPont was added to 300 g of single hollow microparticles (average particle size of 4.2 m, polymeric resin hollow particles, density 0.5 g / cm ³ ) of Sekisui Chemical Co., 3 g of cumyl hydroperoxide was added and mixed with the Henschel mixer at a linear velocity of 40 m / s for 1 minute and 1 minute for 5 times to coat the nanoparticles with the polymeric resin short hollow particles. And crosslinked at 200 DEG C for 10 minutes.

The catalyzed aqueous solution was prepared with palladium chloride (PdCl ₂ ) concentration of 1.6 g / l, tin chloride (SnCl ₂ ) concentration of 25 g / l, and hydrochloric acid (HCl) concentration of 150 ml / l. The hollow particles coated with the fine powder prepared above were placed in an aqueous catalytic treatment solution and stirred at 40 ° C for 10 minutes. After filtration, it was washed twice with distilled water. To 750 ml of distilled water, 150 ml of sulfuric acid (H ₂ SO ₄ ) was added to the diluted aqueous solution for activation treatment, and the mixture was stirred at room temperature for 5 minutes for activation.

The plating solution was adjusted to a concentration of 10 g / l of copper sulfate pentahydrate, a concentration of 37% formaldehyde, a concentration of ethylenediamine tetraacetic acid of 30 g / l, a concentration of 2,2'-dipyridyl of 30 mg / l and a concentration of polyethylene glycol 20 ml / l and the pH was adjusted to 12 with sodium hydroxide. The prepared hollow particles were placed in a plating solution and stirred at 50 캜 for 10 minutes for plating. After copper plating, the resultant was filtered, washed twice with distilled water, and silver-plated by the same method as in Example 4. The density of the hollow conductive particles produced was 1.0 g / cm ³ .

10. Example 10 < Production of Hollow Conductive Particles 6 >

(IM30K, density 0.6 g / cm ³ , average particle size 16 μm) of Seokyung CMT was separated and classified to have an average particle size of 7 μm. 30 g of DuPont nano silica (HS-40) and 20 g of polypyrrole powder as a conductive polymer were charged in a Henschel mixer. The mixture was stirred for 2 minutes at a linear speed of 40 m / s with a Henschel mixer for 5 minutes, Silica and polypyrrole were coated onto the hollow glass particles. Thereafter, silver plating was performed in the same manner as in Example 4. The density of the hollow conductive particles produced was 1.4 g / cm &lt; ^{3 &} gt ;.

11. Examples 11 to 20 < Preparation of coating composition 1 to 10 >

After the surfactant was mixed in the solvent, the hollow conductive particles were added and dispersed. The binder resin was divided into four equal portions, and the resulting mixture was divided into four portions, which were then mixed for one hour with stirring. Then, a curing agent was added and stirred for 1 hour to prepare a coating composition. The weight percentages of the constituents are shown in Table 3.

The binder resin used was epoxy resin, the solvent used ethanol, the hardening agent used phthalic anhydride, and the surfactant used was Southeast Named Synthetic Products.

Component Content of Coating Composition Example Conductive particle
(weight%) Binder resin
(weight%) menstruum
(weight%) Hardener
(weight%) Surfactants
(weight%) Example 11 50 (Example 1) 10 38.8 0.7 0.5 (M-OP1019) Example 12 30 (Example 2) 9 58.3 1.2 1.5 (DQ-590ET) Example 13 65 (Example 3) 3 29.5 0.5 2.0 (EU-DO113) Example 14 68 (Example 4) 4 25.5 0.3 2.2 (E-7) Example 15 31 (Example 5) 48 11.4 6.8 2.8 (M-OP1019) Example 16 60 (Example 6) 7 32 0.8 0.2 (M-OP1019) Example 17 63 (Example 7) 1.5 33.7 0.1 1.7 (M-OP1019) Example 18 41 (Example 8) 20 34.2 2.5 2.3 (M-OP1019) Example 19 35 (Example 9) 30 30.3 3.2 1.5 (M-OP1019) Example 20 38 (Example 10) 40 15.9 4.5 1.6 (M-OP1019)

12. Examples 21 to 30 < Preparation of electromagnetic wave shielding film 1 to 10 >

12-1. Preparation of insulating layer coating solution 1 and insulating layer coating solution 2

1.5% by weight of a non-ionic surfactant (M-OP1019) manufactured by Southeast Asia Co., Ltd. was mixed in 55% by weight of ethanol, and then 42% by weight of polyester was divided into two portions. 1.5% by weight of phthalic anhydride was added and stirred for 1 hour to prepare an insulating layer coating solution 1.

Except that 50 wt% of carbon black was used instead of 50 wt% of conductive particles in the preparation of the coating composition of Example 11 and 10 wt% of polyester was used in place of 10 wt% of epoxy resin, the insulating layer coating solution 2 was used .

12-2. Preparation of electromagnetic wave shielding film 1 to 10

A polyester (PET) film having a thickness of 50 탆 was used as a transfer film, and the above-prepared insulating layer coating solution 1 was coated thereon to a thickness of 6 탆 to form a first insulating layer, and an insulating layer coating solution 2 To form a second insulating layer.

And copper was sputtered thereon to form a copper thin film having a thickness of 100 nm. Then, the copper thin film was placed at a distance of 3 mm from the xenon lamp emitting white light in the wavelength range of 380 nm to 950 nm, and was irradiated with a light energy of 2 J cm ^-2 for 3 milliseconds, and again after 10 milliseconds The irradiation was repeated three times to flash-sinter the copper thin-film layer.

Then, the coating liquid composition of Example 11 was coated to a thickness of 16 탆 to form a conductive thermosetting resin layer. The conductive thermosetting resin layer was subjected to flash light sintering in the same manner as in the above-mentioned flash light sintering method.

Then, a silicon release film having a thickness of 50 탆 was adhered with a protective film to prepare an electromagnetic wave shielding film 1. The presence or absence of a copper thin film layer, whether or not a flash light sintering by a xenon lamp was carried out, and the like, and the production conditions thereof are shown in Table 4.

Example Copper thin film layer Sintering of copper thin film layer The conductive thermosetting resin layer Flash light sintering of conductive thermosetting resin layer Example 21 ○ ○ The coating composition of Example 11 ○ Example 22 ○ × The coating composition of Example 12 × Example 23 ○ ○ The coating composition of Example 13 × Example 24 × × The coating composition of Example 14 × Example 25 ○ ○ The coating composition of Example 15 ○ Example 26 × × The coating composition of Example 16 ○ Example 27 ○ × The coating composition of Example 17 ○ Example 28 ○ × The coating composition of Example 18 × Example 29 ○ ○ The coating composition of Example 19 × Example 30 ○ × The coating composition of Example 20 ○

[Comparative Example 1] < Production of hollow conductive particles >

(Average particle size of 4.2 mu m, polymeric resin hollow particles, density of 0.5 g / cm &lt; ³ &gt;) of Sekisui Chemical Co., Ltd. (Japan) were silver-plated in the same manner as in Example 4. [ The density of the produced conductive particles was 0.8 g / cm ³ .

[Comparative Example 2] < Production of non-hollow-core conductive particles >

(VGCF) and copper powder (average particle size of 3 占 퐉) as a conductive agent and cumyl hydroperoxide as a crosslinking agent in a weight ratio of 45: 43: 10: 2 (molecular weight: 70,000) as a polymer binder, Was the same as that in Example 1 except that high molecular weight polyethylene (molecular weight: 70,000), vapor grown carbon fiber (VGCF) and copper powder (average particle size: 3 μm) were used at a weight ratio of 38: 38: Non-conductive particles were prepared. The non-pore-forming conductive particles were not crosslinked because no crosslinking agent was used, and had an average particle size of 6.8 mu m and a density of 3.3 g / cm &lt; ^{3 &} gt ;.

[Comparative Example 3] < Production of coating composition using conductive particles >

A coating composition was prepared in the same manner as in Example 11, except that the conductive particles of Comparative Example 1 were used in place of the conductive particles of Example 1.

[Comparative Example 4] < Production of coating composition using conductive particles >

A coating composition was prepared in the same manner as in Example 13, except that the conductive particles of Comparative Example 2 were used in place of the conductive particles of Example 3.

[Comparative Example 5] < Production of electromagnetic wave shielding film >

An electromagnetic wave shielding film was prepared in the same manner as in Example 24 except that the coating composition of Comparative Example 3 was used in place of the coating composition of Example 14.

[Comparative Example 6] < Production of electromagnetic wave shielding film >

An electromagnetic wave shielding film was prepared in the same manner as in Example 24 except that the coating composition of Comparative Example 4 was used in place of the coating composition of Example 14.

[Performance evaluation of Examples 1 to 30 and Comparative Examples 1 to 6]

The performances of Examples and Comparative Examples were evaluated and shown in Tables 5 to 8. As shown in Table 5, the conductive particles of Examples 1 to 10 and Comparative Example 1 had a specific gravity of 3 or less and a low specific gravity. The specific gravity of the non-conductive conductive particles of Comparative Example 2 was 3.3 and the specific gravity was 3 or more.

Density of conductive particles Example Density of conductive particles Example Density of conductive particles Example Density of conductive particles Example 1 2.2g / cm ³ Example 5 0.3g / cm ³ Example 9 1.0g / cm ³ Example 2 2.1g / cm ³ Example 6 2.6g / cm ³ Example 10 1.4g / cm ³ Example 3 2.8g / cm ³ Example 7 2.8g / cm ³ Comparative Example 1 0.8g / cm ³ Example 4 2.9 g / cm &lt; ³ &gt; Example 8 1.7g / cm ³ Comparative Example 2 3.3g / cm ³

The coating compositions of Examples 11 to 20 and the coating compositions of Comparative Examples 3 to 4 were placed in a 300 ml beaker and stored at room temperature for 30 days. As shown in Table 6, the coating compositions of Examples 11 to 20 and Comparative Example 3 using low specific gravity conductive particles of 3 or less did not precipitate, but the coating composition of Comparative Example 4 using 3 or more high specific gravity hollow conductive particles Precipitation occurred.

After 30 days, the presence or absence of deposition of conductive particles in the coating composition Example Precipitation of conductive particles Example Precipitation of conductive particles Example Precipitation of conductive particles Example 11 none Example 15 none Example 19 none Example 12 none Example 16 none Example 20 none Example 13 none Example 17 none Comparative Example 3 none Example 14 none Example 18 none Comparative Example 4 has exist

The electromagnetic wave shielding rate was measured with a measurement frequency range of 30 MHz to 1 GHz, a measurement method of vertical, a horizontal direction (using an antenna coupon), and a measurement distance of 3 M (inside the electromagnetic wave completely shielded chamber). The electromagnetic wave shielding properties of the electromagnetic wave shielding films of Examples 21 to 30 and the electromagnetic wave shielding films of Comparative Examples 5 to 6 were evaluated and shown in Table 7. The electromagnetic wave shielding performance of each of Examples 21 to 30 was superior to all of the electromagnetic wave shielding properties of 55 dB or more, but the electromagnetic wave shielding performance of Comparative Examples 5 to 6 was less than 50 dB.

In Comparative Example 5, hollow particles of polymer resin were used. However, since silver was plated without preparing the multi-component composite powder, that is, in the state where the surface was not reformed to improve the plating, the plating was poor and the electromagnetic wave shielding performance deteriorated.

The conductive particles used in Comparative Example 6 were non-bumpy conductive particles prepared by mixing vapor-grown carbon fibers and copper powder as a conductive agent in high-density polyethylene, and had a specific gravity of 3.3. The specific gravity is so high that when the conductive thermosetting resin layer is formed by coating a coating composition containing the conductive polymer particles, the electroconductive particles are not uniformly coated due to the precipitation of the conductive particles.

Electromagnetic wave shielding performance of electromagnetic wave shielding film Example Electromagnetic wave shielding rate Example Electromagnetic wave shielding rate Example Electromagnetic wave shielding rate Example 21 60dB Example 25 56dB Example 29 61dB Example 22 63dB Example 26 59dB Example 30 58dB Example 23 61dB Example 27 60dB Comparative Example 5 39dB Example 24 62dB Example 28 57dB Comparative Example 6 48dB

The solder dip / float test evaluates the heat resistance of whether the electromagnetic wave shielding film can withstand a high temperature soldering process. After the electromagnetic wave shielding film sample is baked in a drier at 135 ± 5 ° C. for 1 hour Repeat the dipping for 10 seconds in the solder pot at 288 ± 5 ℃ three times. Repeat 3 times for 10 seconds on the solder pot of 260 ± 5 ℃. The experimental results are shown in Table 8. As shown in Table 8, Examples 21 to 30 were acceptable, but Comparative Example 5 and Comparative Example 6 were rejected.

Solder Dip / Float Test Result of Electromagnetic Wave Shielding Film Example Solder Dip / Float Test Example Solder Dip / Float Test Example Solder Dip / Float Test Example 21 pass Example 25 pass Example 29 pass Example 22 pass Example 26 pass Example 30 pass Example 23 pass Example 27 pass Comparative Example 5 fail Example 24 pass Example 28 pass Comparative Example 6 fail

In Comparative Example 5, when the polymer hollow fine particles were used as the conductive particles without being crosslinked, the heat resistance was poor and failed. In Comparative Example 6, even when the constituent component was a polymer, non-rigid conductive particles were used as the conductive particles without being crosslinked, and the heat resistance was poor and failed. On the other hand, in the case of Examples 21 to 30, since the polymer resin was a constituent component of the conductive particles, all of them were crosslinked and the heat resistance was improved.

10: Transfer film
20: first insulating layer
30: second insulating layer
40: conductive thermosetting resin layer
50: Protective film

Claims (15)

In the electromagnetic wave shielding film,
A transfer film;
A first insulating layer formed adjacent to the transfer film;
A second insulation layer formed adjacent to the first insulation layer;
A conductive thermosetting resin layer formed adjacent to the second insulating layer and formed by coating a coating composition comprising conductive particles having a specific gravity of 3 or less;
And a protective film formed adjacent to the conductive thermosetting resin layer,
Wherein the conductive particles are composed of any one selected from non-rigid conductive particles obtained by mixing and crosslinking a polymer resin, a conductive material and a crosslinking agent, or hollow conductive particles,
Wherein the non-
(a) a polymer selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl chloride, poly methyl meta acrylate, polybutadiene and copolymers thereof To one or more polymer resins selected from the group consisting of:
(b) Vapor grown carbon fiber (VGCF), conductive carbon black, ketjen black, acetylene black , furnace black, thermal black, channel black, a channel black, a carbon fiber, a carbon nanotube, a graphite, a graphene, a conductive polymer, and a metal powder;
(c) dicumyl peroxide, benzoyl peroxide, lauryl peroxide, tert-butyl cumyl peroxide, di (t-butylperoxy) 2,5-dimethyl-2,5-di (tert-butylperoxy isopropyl) benzene, 2,5-dimethyl- butyl peroxy) hexane, and di-tert-butyl peroxide, and crosslinking the mixture.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
delete The method according to claim 1,
Wherein the non-conductive particle is at least one of copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, titanium, molybdenum, antimony, tantalum, vanadium, And a polymer is coated with one or a plurality of selected ones.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to claim 1,
One or more kinds selected from organic-based powder (powder), inorganic-based powder, carbon-based powder, and metal-based powder whose average diameter of the powder particles is 1/5 to 1 / 10,000 of the average diameter of the non- Characterized in that a powder is coated on the surface of the non-perforated conductive particle.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
5. The method of claim 4,
Wherein the non-conductive particle is at least one of copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, titanium, molybdenum, antimony, tantalum, vanadium, And a polymer is coated with one or a plurality of selected ones.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to claim 1,
The hollow (conductive)
(a) a mixture of hollow particles composed of a plurality of mixed materials selected from organic materials, inorganic materials, carbon-based materials, and metal-based materials;
(b) organic hollow particles excluding the polymer resin system;
(c) inorganic hollow particles;
(d) carbon-based hollow particles;
(e) metal-based hollow particles;
And one or more types selected from the group consisting of:
Wherein the particles are hollow particles or multipole particles.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to claim 1,
The hollow (conductive)
(a) polymeric resin hollow conductive particles or
(b) a hollow conductive particle in which one or a plurality of materials selected from an organic material, an inorganic material, a carbonaceous material, and a metallic material is mixed with the polymer resin;
(c) dicumyl peroxide, benzoyl peroxide, lauryl peroxide, tert-butyl cumyl peroxide, di (t-butylperoxy) 2,5-dimethyl-2,5-di (tert-butylperoxy isopropyl) benzene, 2,5-dimethyl- butyl peroxy hexane and di-tert-butyl peroxide, or mixing and crosslinking the particles with a particulate constituent;
Wherein the particles are hollow particles or multipole particles.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
8. The method according to any one of claims 6 to 7,
Wherein the hollow conductive particles are coated with a metal selected from the group consisting of copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, titanium, molybdenum, antimony, tantalum, vanadium, Palladium, bismuth, and a conductive polymer.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to claim 6,
One or more kinds selected from organic-based powder (powder), inorganic-based powder, carbon-based powder and metal-based powder whose average diameter of the powder particles is one fifth to one-tenth of the average diameter of the hollow Is coated on the surface of the hollow particles,
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
10. The method of claim 9,
The hollow conductive particles may be coated on the surface of the hollow particles with a binder such as copper, silver, gold, platinum, iron, aluminum, nickel, manganese, zinc, tin, magnesium, zirconium, tungsten, cobalt, titanium, molybdenum, Vanadium, palladium, bismuth, and a conductive polymer.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to any one of claims 4, 6, and 7,
Wherein the material constituting the organic powder, the organic material, the organic hollow particles, and the polymer resin is composed of one or more selected from the group consisting of polypyrrole, polythiophene, polyaniline, and derivatives thereof, which is an electroconductive polymer having a conjugated structure.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to claim 1,
The coating composition may comprise,
(1) 30 to 70% by weight of conductive particles having a specific gravity of 3 or less;
(2) 0.3 to 50% by weight of a thermosetting binder resin;
(3) 10 to 60% by weight of a solvent;
(4) 0.1 to 7% by weight of a curing agent;
(5) 0.1 to 3% by weight of a surfactant.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to claim 1,
Characterized in that one or more metal thin film layers formed by any one or a plurality of methods selected from sputtering, vacuum deposition, metal spraying and ion plating are added between the second insulating layer and the conductive thermosetting resin layer ,
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
14. The method of claim 13,
The metal thin film layer is irradiated with a white flash using a xenon lamp, and a high voltage is generated and sintered in a short period of microseconds to milliseconds using a high voltage pulse power supply &Lt; / RTI &gt;
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.
The method according to any one of claims 1, 13 and 14,
The conductive thermosetting resin layer is irradiated with a white flash with a xenon lamp, and a high voltage is generated in a short period of microseconds to milliseconds using a high voltage pulse power supply Sintered.
An electromagnetic wave shielding film using a coating composition comprising low specific gravity conductive particles.

Images