KR20110104456A - Electro-conductive resin composition - Google Patents

Abstract

The present invention provides an electrically conductive composite resin composition for use as a molding material for an information and communication device requiring a radio wave transmission / reception function, comprising: 30 to 60 wt% of a polymer resin; And 3 to 15 wt% of carbon black as the conductive material, 2 to 10 wt% of carbon nanotubes, and 30 to 55 wt% of carbon fibers for electrically connecting the conductive carbon black to the carbon nanotubes. It relates to an electrically conductive composite resin composition.
According to the present invention, it is possible to manufacture a finished product only by injection molding or insert injection process, if necessary, and also to manufacture a mobile phone antenna terminal using a non-electrically conductive composite resin composition, when using a conventional metal material Compared with this, it is possible to block electromagnetic waves more effectively.

Description

Electroconductive composite resin composition {ELECTRO-CONDUCTIVE RESIN COMPOSITION}

The present invention relates to an electrically conductive composite resin composition, and more particularly, in the production of IT devices such as cellular phone terminals or terminals, polymer resin, conductive carbon black, carbon nanotube, It relates to a conductive composite resin composition comprising a carbon fiber and an additive.

Recently, due to the development of electronic technology, miniaturization, high integration, and high performance of electronic products have been achieved. Accordingly, a material with high thermal conductivity is strongly required to efficiently remove heat generated in electronic components embedded in electronic devices. At the same time, there is a demand for development of a material capable of effectively blocking electromagnetic interference (EMI).

In particular, with the development of the mobile communication industry, mobile communication terminal (mobile phone) antenna technology has also been developed, and the characteristics of light and short (small size, light weight) are required. Although it started with the existing external antenna, intenna in the form of a metal plate antenna (MPA), which is an internal antenna that attaches the antenna mechanism to the inside of a mobile phone in consideration of portability and design, has been adopted. Currently, the most commonly used MPA material is a magnesium alloy substrate processed by die casting. However, the appearance is less beautiful and heavy compared to the plastic material.

However, in the case of the conventional magnesium alloy, since all processes such as melting, casting, post-processing and surface treatment are performed, there is a problem that the cost is increased and the process is long.

That is, in case of magnesium alloy substrate by conventional metal die casting, additional surface finishing is required to secure dimensional tolerance and flatness, and also plating process to prevent corrosion and through-hole for fastening to attach PCB substrate. Secondary post-processing, such as), is required, and defects caused by fine pinholes on the surface also exist as factors of increasing process costs.

In addition, since magnesium alloy is essentially a metal material, it is easy to generate electromagnetic waves, which may cause communication interference due to electromagnetic waves.

The present invention was created in view of the above-described problems in the prior art, and is used to replace a magnesium alloy in a mobile phone antenna terminal, thereby reducing the cost, shortening the process, and conduction efficiency which can improve electromagnetic wave shielding efficiency. It is a main subject to provide a composite resin composition.

In addition, since the performance of the antenna increases in proportion to the size and volume, the transmission and reception performance is increased. Therefore, since the antenna occupies a substantial portion of the inside of the mobile phone, it acts as a barrier to the slimming of the mobile phone. It is another object of the present invention to provide.

The conductive composite resin composition according to the present invention for solving the above problems, in the conductive composite resin composition for use as a molding material for information and communication devices requiring radio wave transmission and reception function, 30 to 60 wt% of a polymer resin; And 3 to 15 wt% of carbon black as the conductive material and 30 to 55 wt% of carbon fiber for electrically connecting the carbon black to each other.

In addition, the conductive composite resin composition according to the present invention, in the conductive composite resin composition for use as a molding material for information and communication devices that require radio wave transmission and reception function, 30 to 60 wt% of a polymer resin; 2 to 10 wt% of carbon nanotubes and 30 to 55 wt% of carbon fibers for electrically connecting the carbon nanotubes as conductive materials.

In addition, the conductive composite resin composition according to the present invention, in the conductive composite resin composition for use as a molding material for information and communication devices that require radio wave transmission and reception function, 30 to 60 wt% of a polymer resin; It may be configured to include 3 to 15 wt% of carbon black, 2 to 10 wt% of carbon nanotubes, and 30 to 55 wt% of carbon fibers for electrically connecting the conductive carbon black and carbon nanotubes as conductive materials. have.

In addition, the conductive composite resin composition according to the present invention preferably further comprises a coupling agent (Coupling Agent) for bonding the polymer resin and the conductive material further comprises 0.2 to 5 wt%.

Here, the binder, maleic anhydride (maleic anhydride); It is characterized in that it comprises a; combined with the maleic anhydride (maleic anhydride), having an epoxy group (glycidylmethaacrylate) or oxazolline (oxazoline).

In addition, it is preferable that the electrically conductive composite resin composition according to the present invention further comprises 1 to 3 wt% of a lubricant or a dispersant for a smooth extrusion operation.

The lubricant or dispersant may include at least one of waxes (PE wax, LC wax), zinc stearate, zinc stearate, magnesium stearate, and magnesium stearate. It is characterized by.

In addition, the polymer resin, polypropylene (PP), polyurethane (PU), polyethylene (PE), polyamide (PA-6, PA-66; nylon), polystyrene (PA), acrylonitrile butadiene styrene (ABS) , Phenylpropanolamine (PPA), and modified polyphenylene ether (m-PPE), characterized in that it comprises at least one.

In addition, it is preferable that the conductive composite resin composition according to the present invention further comprises 5 to 20 wt% of an inorganic filler for reinforcing mechanical strength.

Here, the inorganic filler is characterized in that it comprises at least one of glass fiber, talc (talc), calcium carbonate, silica.

According to the present invention, since the finished product can be manufactured only by injection molding or an insert injection process, if necessary, cost reduction and process shortening can be expected as compared with conventional metal materials such as magnesium.

In addition, according to the present invention, since the cell phone antenna terminal, etc. are manufactured using the non-metal conductive composite resin composition, it is possible to block electromagnetic waves more effectively than when using a conventional metal material.

In addition, according to the present invention, the conductive composite resin composition is an electrical conductor and paramagnetic (para-magnetic), so can expect the EMI / ESD shielding function of the mobile phone.

In addition, according to the present invention, by replacing the mobile phone antenna with a conductive plastic substrate by uniaxial injection or insert injection using an electrically conductive composite resin composition, the secondary post-processing process required for metal die casting is omitted, thereby significantly reducing the manufacturing process cost. It is expected to be able.

In addition, since the specific gravity (1.15) of the composite resin composition according to the present invention is about 35% smaller than the specific gravity (1.8) of the magnesium alloy, the weight reduction effect of the mobile phone can be expected.

1 is a schematic diagram showing the configuration of electromagnetic shielding efficiency.

Hereinafter, a preferred embodiment of the electrically conductive composite resin composition according to the present invention will be described in more detail.

The conductive composite resin composition according to the present invention has a structure in which a conductive material is added based on a polymer resin, and is configured to express electrical conductivity.

Here, the polymer resin is preferably made of a molecular weight of about 160,000 ~ 200,000, for example, polypropylene (PP), polyurethane (PU), polyethylene (PE), polyamide (PA-6, PA-66; nylon), Polystyrene (PA), acrylonitrile butadiene styrene (ABS), phenylpropanolamine (PPA), and may be composed of one or two or more selected from the group consisting of modified polyphenylene ether (m-PPE).

In addition, the polymer resin is preferably included in the conductive composite resin composition of the present invention in 30 ~ 60 wt%. Here, when the polymer resin is less than 30 wt%, the physical strength is lowered. When the polymer resin is more than 60 wt%, the amount of the conductive material to be added relatively decreases, and the electrical conductivity is lowered.

The conductive material serves to impart electrical conductivity to the conductive composite resin composition of the present invention, and includes at least one group selected from the group consisting of carbon black, carbon fiber, carbon nanotube, and metal powder. Can be made.

For example, in the conductive composite resin composition of the present invention, the conductive carbon black may contain 3 to 15 wt%, 2 to 10 wt% of carbon nanotubes, and 30 to 55 wt% of carbon fibers.

Here, the carbon black is a material having a relatively low cost, while the main component is carbon (C) and has electrical conductivity as a structural semi-crystalline like the graphite.

On the other hand, the carbon nanotubes are a crystalline structure having a directionality, but a material having a relatively high electrical conductivity but high price than carbon black.

In addition, the carbon fiber is a conductive material having a fiber structure, and serves as a medium for connecting carbon black and carbon nanotubes, between carbon black and carbon black, and between carbon nanotubes and carbon nanotubes.

As such, the conductive material added to the polymer resin has a structure in which carbon black, carbon nanotubes, and carbon fibers are organically connected to increase the overall electrical conductivity.

On the other hand, when the carbon black is less than 3 wt%, the electrical conductivity is inferior, and if it exceeds 15 wt%, the mechanical strength may be lowered. In addition, when the carbon black exceeds 15 wt%, the carbon black may be released from the polymer resin and contaminate the electronic circuit boards attached thereto.

If the carbon nanotubes are less than 2 wt%, the electrical conductivity is lowered. If the carbon nanotubes are more than 10 wt%, the cost of the carbon nanotubes increases due to the expensive carbon nanotubes.

In addition, if the carbon fiber is less than 30 wt%, the effective electrical conductivity is lowered, if it exceeds 55 wt%, the basic polymer resin content is lowered, the physical strength is lowered.

In addition, the conductive composite resin composition of the present invention may further include an additive for combining the polymer resin and the conductive material, such additives are 0.2 to 5 wt% of a coupling agent, and 1 to 3 wt% of a lubricant or a dispersant. May be included as a%.

That is, a binder (coulpling agent) is used to improve the interfacial adhesion between polypropylene (PP) used as the base resin, talc, calcium carbonate, glass fiber used as an inorganic reinforcing agent, and carbon fiber which is a conductive material. Such a binder can improve the compatibility with heterogeneous inorganic additives with respect to the polymer resin, so that a larger amount of conductive material can be included, as well as mechanical strength such as elongation, flexural strength, impact strength, and elastic modulus. It will play a role in improving the quality.

For example, using an acid anhydride such as maleic anhydride and a co-extruded binder by adding amines such as diethylamine (DEA), As surface modification occurs between the propylene (PP) resin and these binders, physical reinforcing effects are exhibited. As the representative binder, maleic anhydride, acrylic acid having an epoxy group (glycidylmethaacrylate), or oxazoline (oxazoline) is preferably used.

Here, the acid anhydride such as maleic anhydride is ring-opened by reaction with an amine, and becomes an imine compound, followed by a dehydration reaction, thereby forming a heterogeneous bond. .

And acid anhydride (acid anhydride) used as the binder is preferably added in the range of 0.2 ~ 5 wt%. Acid anhydrides can generally be ignited by violently reacting with moisture generated during the reaction extrusion if they are added in excess of 5 wt%, and when the addition amount is less than 0.2 wt%, cross-linking reactions are very weak. Or it is difficult to expect a physical reinforcing effect.

Apart from this, ethylene copolymers (EMA, EEA, EBA) in which ethylene and acrylic acid are polymerized with their own polarity while having compatibility with polypropylene (PP) may be used as non-reactive compatibilizers.

Alternatively, DuPont's Fusabond M613-05 may be used as a representative commercial binder.

On the other hand, when the heterogeneous inorganic material is added to the polymer resin to perform the compounding operation, when the compatibility member and the inorganic content between the heterogeneous compounds are relatively higher than the resin amount, the smooth extrusion may not occur.

In this case, it is preferable to use an internal lubricant or a dispersant for smooth extrusion, and such a lubricant or dispersant is low molecular weight wax (PE wax, LC wax), zinc stearate, calcium stearate (Ca) metal stearic acid such as stearate, magnesium stearate, and the like.

And the lubricant / dispersant used in the present invention is preferably limited to 1 to 3 wt% range.

When the lubricant / dispersant exceeds 3 wt%, low molecular weight waxes or metal stearic acid are easily eluted, causing wax components to migrate to the surface of the structure, causing surface defects. In addition, when the wax component is transferred to the surface of the injection structure (intena substrate), the electrical conductivity is lowered, and thus the reverse function may be weakened.

When the lubricant / dispersant is used at less than 1 wt%, it is difficult to expect a sufficient kneading effect, so that the dispersion / distribution degree of the inorganic filler to be added decreases, and thus mechanical strength may be lowered.

On the other hand, in addition to the components described above as another embodiment, the electrically conductive composite resin composition of the present invention, the inorganic filler made of at least one group of glass fibers, talc, calcium carbonate, silica to reinforce the mechanical strength ) May be further included.

Pure polypropylene polymer resins have high flexural modulus, so their relative dimensional stability and mechanical strength are weak.In order to reinforce them, stiffness is added by adding inorganic powders such as glass fiber, talc, calcium carbonate, and silica. expect a reinforce effect.

That is, the inorganic powder particles act as a nucleating agent (nuclearing agent) that affects the crystal formation of the polypropylene resin and produces a kind of anchor effect to improve mechanical strength.

Here, the inorganic filler is preferably included in the conductive composite resin composition of 5 to 20 wt% of the present invention.

When the inorganic filler is added at less than 5 wt%, the inorganic filler may not serve as a nucleating agent that affects the crystal formation of the polypropylene resin, thereby lowering the mechanical strength.

On the other hand, when the inorganic filler is added in excess of 20 wt%, it is compounded with the existing conductive additives carbon black, carbon fiber, carbon nanotubes, so that the content of the polymer resin impregnating these fillers is very small Because of insufficient binding role, the mechanical strength is rather adversely affected.

In addition, the conductive composite resin composition of the present invention is preferably configured such that the electrical conductivity (surface resistance) is 10 ohm or less, preferably 5 ohm or less, and more preferably 1 to 3 ohm.

In other words, the electrical characteristics and surface resistance of the antenna substrate using a conventional magnesium alloy substrate is required in the range of about 1 ~ 3 ohm, so it is suitable for the polypropylene composite resin, which is an insulator, to replace the magnesium alloy substrate with a conductive thermoplastic composite resin. It is desirable to add an electrically conductive material (carbon black, carbon fiber, carbon nanotube) and an inorganic filler in an amount to satisfy the required electrical properties (conductivity, surface resistance).

Meanwhile, referring to FIG. 1, the electromagnetic wave shielding efficiency is substantially reduced after the reflected wave Er reflected from the shielding agent surface and the absorbing wave Ea absorbed by the shielding agent with respect to the electromagnetic wave E1 generated by accident. It can be expressed as the difference between the transmission waves E2 transmitted through the shielding agent.

That is, the electromagnetic shielding efficiency is proportional to the conductivity (surface resistance G value) and the permeability (μ, reciprocal of volume resistance; Ω / cm 2) of the shielding agent, so the conductivity of the conductive composite resin is a very important factor.

As such, the conductive composite resin composition according to the present invention has excellent electromagnetic shielding efficiency because the conductive composition is very high because carbon black, carbon nanotubes, and carbon fibers are organically connected.

Example 1.

45 wt% of copolymer polypropylene (c-PP) and 10 wt% of conductive carbon black (Kejchen Black 600J or similar grade) having an average particle size of about 25-50 nm, particle size distribution of nanotubes 40-40 nm, length distribution 10 5 wt% of carbon nanotubes with a diameter of about 30 µm, 35 wt% of carbon fibers with a diameter of 4-12 µm with a filament diameter distribution, and a compatibilizer for smooth bonding between different materials 15 wt% of low molecular weight PE wax was added to the composite resin in a single screw extruder to inject ASTM specimens.

Example 2.

45 wt% of copolymer polypropylene (c-PP) and 10 wt% of conductive carbon black (Kejchen Black 600J or similar grade) having an average particle size of about 25-50 nm, particle size distribution of nanotubes 40-40 nm, length distribution 10 5 wt% of carbon nanotubes having a diameter of ˜30 μm, 35 wt% of carbon fibers having a diameter of 4-12 μm with a filament diameter distribution, and 35 wt% of carbon fibers having a length distribution of 5-7 mm, and glass fibers (G / F) for reinforcing mechanical strength 8 wt%, and 1 wt% of silane-based binder and 3 wt% of polyurethane-based sizing agent to improve the bonding force between different materials, the internal stress during compound kneading, the internal stress to reduce friction and smooth dispersion 3 wt% of calcium stearate (Ca / st) or magnesium stearate (Mg / st) is added as a lubricant / dispersion agent, respectively, and composite resin is formed in a single screw extruder to inject each of the physical properties of the ASTM standard. It was.

Example 3.

60 wt% of copolymer polypropylene (c-PP) and 5 wt% of conductive carbon black (Kejchen Black 600J or similar grade) having an average particle size of about 25-50 nm, particle size distribution of nanotubes 40-300 nm, length distribution 10 3 wt% of carbon nanotubes with a diameter of about 30 µm, 10 wt% of carbon fibers having a diameter of 4-12 µm with a filament diameter distribution, and 15 wt of glass fiber (G / F) for reinforcing mechanical strength. % And 1 wt% of silane-based binder and 3 wt% of polyurethane-based sizing agent to improve the bonding force between dissimilar materials, internal lubricant for compound kneading, reduction of internal stress, friction and smooth dispersion Formulate calcium stearate (Ca / st) or magnesium stearate (Mg / st) 3wt% as a lubricant / dispersion agent, respectively, and composite the resin using a kneader and a single screw extruder Each was injected.

Test example.

In order to measure the mechanical strength and electrical properties of each of the composite resin (compound) composition ratios made in Examples 1 to 3, specimens prepared according to ASTM were manufactured using a single screw extruder. It was measured according to the method, the results are shown in Table 1.

Specific gravity: measured according to ASTM D 792 method.

Tensile strength: measured according to ASTM D 638 method.

Flexural strength / flexural modulus: measured according to ASTM D 790 method.

Impact strength: measured according to ASTM D 256 method.

Conductivity (volume resistance): measured according to ASTM D 257 method.

Example 1 Example 2 Example 3 Magnesium Alloy Substrate (MG) importance 1.18 1.15 1.12 1.81 Tensile Strength (kgf / ㎠) 530 580 740 2,300 Flexural Strength (kgf / ㎠) 520 605 1,200 16,500 Flexural modulus (kgf / ㎠) 163,000 136,500 180,000 300,000 Impact strength (kgf / ㎠) 6.3 6.4 8.6 14 Conductivity (Ωcm) 4.2 1.8 8.2 2.0

As shown in Table 1, carbon black (C / B), carbon nanotubes (CNT), carbon fibers (C / F) and metallic powders in the copolymer polypropylene resin which is a thermoplastic resin according to the present invention. Excellent conductivity was realized in the composite resin to which the conductive filler was added.

In addition, in the case of Example 2, it can be confirmed that the electrical conductivity is further improved by using a fine carbon fiber compared to Example 1.

In addition, in the case of Example 3, compared with Examples 1 and 2, the amount of carbon nanotubes and carbon fibers was added, whereby the electrical conductivity was relatively low.

In addition, when the additives (binders, sizing agents, lubricants, etc.) and glass fibers were added to reinforce the physical strength, excellent mechanical strength could be obtained.

On the other hand, the mechanical strength range of the substrate for intenna commonly applicable in the art is as follows.

Tensile Strength: 500 ~ 1,200kgf / ㎠

-Flexural Strength: 500 ~ 2,500kgf / ㎠

-Flexural modulus: 100,000 ~ 200,000kgf / ㎠

-Impact strength: 6 ~ 16kgf / ㎠

Conductivity: 10Ω㎝ or less

Although, as shown in the present experimental example, the conventional magnesium alloy substrate (MG) has a very strong mechanical strength compared to the embodiment according to the present invention, in view of the requirements of the art, the present invention According to Examples 1 to 3, the conductive composite resin composition has a specific gravity lower than that of the conventional magnesium alloy substrate MG, and can be confirmed to satisfy the required mechanical strength and electrical properties while being about 35% lighter.

According to the embodiment of the present invention, it is possible to satisfy the physical property level of the existing magnesium alloy substrate (MG) and at the same time have a low specific gravity, thereby increasing the weight reduction effect and having a suitable mechanical strength.

The conductive composite resin composition of the present invention configured as described above may be used as a molding material such as an IT device, for example, an intena substrate for a mobile phone, a telematics substrate for a vehicle, a DMB substrate, and the like, which require a radio wave transmission and reception function.

In addition, by using the conductive composite resin composition of the present invention, a function capable of assisting the transmission / reception improvement of the external antenna or the internal antenna may be implemented.

When manufacturing a mobile phone antenna terminal using the conductive composite resin composition of the present invention configured as described above, it is possible to manufacture the finished product only by injection molding or insert injection process, if necessary, die-cast expensive metal materials such as magnesium and the basic structure After forming, cost reduction and process shortening are possible as compared with the prior art which undergoes a post-processing process such as CNC machining.

In addition, since the mobile terminal antenna is manufactured using the non-metal conductive composite resin composition, it is possible to block electromagnetic waves more effectively than when using a conventional metal material.

While the invention has been shown and described with respect to the specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Anyone with it will know easily.

Claims (10)

In the electrically conductive composite resin composition for use as a molding material for information and communication devices that require radio wave transmission and reception function,
30 to 60 wt% of a polymer resin;
30 to 55 wt% of carbon fibers for electrically connecting between 3 to 15 wt% of carbon black as the conductive material and the carbon black;
Conductive composite resin composition comprising a. In the electrically conductive composite resin composition for use as a molding material for information and communication devices that require radio wave transmission and reception function,
30 to 60 wt% of a polymer resin;
2 to 10 wt% of carbon nanotubes as the conductive material and 30 to 55 wt% of carbon fibers for electrically connecting the carbon nanotubes;
Conductive composite resin composition comprising a. In the electrically conductive composite resin composition for use as a molding material for information and communication devices that require radio wave transmission and reception function,
30 to 60 wt% of a polymer resin;
3 to 15 wt% of carbon black as the conductive material, 2 to 10 wt% of carbon nanotubes, and 30 to 55 wt% of carbon fibers for electrically connecting the conductive carbon black to the carbon nanotubes;
Conductive composite resin composition comprising a. 4. The method according to any one of claims 1 to 3,
A coupling agent (Coupling Agent) for bonding the polymer resin and the conductive material is 0.2 to 5 wt%;
An electrically conductive composite resin composition, further comprising a. The method of claim 4, wherein the binder,
Maleic anhydride;
Acrylic acid (glycidylmethaacrylate) or oxazoline combined with the maleic anhydride and having an epoxy group;
Conductive composite resin composition, characterized in that comprises a. 4. The method according to any one of claims 1 to 3,
Lubricants or dispersants 1-3 wt% for smooth extrusion;
An electrically conductive composite resin composition, further comprising a. The method of claim 6, wherein the lubricant or dispersant,
Electrically conductive composite resin composition comprising at least one of wax (PE wax, LC wax), zinc stearate, zinc stearate, Ca stearate, Mg stearate . The polymer resin according to any one of claims 1 to 3, wherein
Polypropylene (PP), Polyurethane (PU), Polyethylene (PE), Polyamide (PA-6, PA-66; Nylon), Polystyrene (PA), Acrylonitrile Butadiene Styrene (ABS), Phenylpropanolamine (PPA ), And a modified polyphenylene ether (m-PPE) at least any one comprising a conductive composite resin composition. 4. The method according to any one of claims 1 to 3,
Inorganic filler 5 to 20 wt% to reinforce mechanical strength;
An electrically conductive composite resin composition, further comprising a. The method of claim 9, wherein the inorganic filler,
An electrically conductive composite resin composition comprising at least one of glass fibers, talc, calcium carbonate and silica.

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