KR20060093794A - Resin-basd caron nanotube hybrid materials with high thermal conductivity - Google Patents

Abstract

The present invention relates to a planar heating element using carbon nanotubes having improved electrical and thermal conductivity by adding carbon nanotubes and a method of manufacturing the same.

The manufacturing method of the present invention comprises a first step of forming a heat generating part by mixing and dispersing carbon nanotubes having an average length of several tens to several hundreds of micrometers in a polymer resin substrate at a constant mass ratio with respect to the polymer resin substrate; A second step of forming a sheet-shaped electrode part with an electrical resistance in a range of 1 to 10 kW in the heat generating part mixed and dispersed in the first step; And a third step of attaching an insulating portion having high conductivity to the electrode portion.

      Carbon Nano Tube, Planar Heating Element

Description

Planar heating element using carbon nanotube and its manufacturing method {Resin-basd Caron Nanotube Hybrid Materials with High Thermal Conductivity}

1 is a process diagram illustrating a manufacturing process of the present invention.

2 is a perspective view showing a state in which carbon nanotubes are dispersed in a matrix

3 shows a planar heating element using carbon nanotubes as a heating unit,

       (a) is a front view, (b) is a top view.

Figure 4 shows a planar heating element of another embodiment using carbon nanotubes,

       (a) is a front view, (b) is a top view.

<Explanation of symbols for the main parts of the drawings>

100... Heating portion 200... Electrode part 300.. Insulation

The present invention relates to a planar heating element using carbon nanotubes having improved electrical and thermal conductivity by adding carbon nanotubes and a method of manufacturing the same.

In general, composite materials having thermal conductivity are thermally conductive by uniformly distributing a material having high thermal conductivity (gold, silver, copper, aluminum, iron, graphite powder, AIN, etc.) on a substrate such as a resin. .

As proposed in US Pat. No. 6,372,337 as a prior art, a thermally conductive grease is prepared by mixing 500-1,200 wt% of a metal powder having an average particle diameter of 0.5 μm to 5 μm with respect to 100 weight of oil as a known substance. .

See also US Pat. No. 4,544,696 to Shaheen (calcium, aluminum and gold, copper or silver in the resin); Nos. 4,544,696 (Streusand), 4,584,336 (Pate) and 4,588,768 (Streusand) (silicon nitride containing-organic polysiloxanes with aluminum oxide or zinc oxide); Paterson (silicon metals and boron nitrides in aluminum nitride and polyorganosilicon resin matrices); And 5,352,731 (Nakano) (aluminum oxide containing silicone rubber).

U. S. Patent No. 5,430, 085 (Acevedo) discloses 80 wt% conductive particles having a particle size in the range of 300 μm to 325 μm, 10 wt% conductive particles having a particle size in the range of 75 to 80 μm, and a length in the range of 0.020 to 0.025 inch. Thermal and electrically conductive caulks are described that include a resin, such as silicone, mixed with a filler comprising 10% by weight of conductive fibers having a.

US Pat. No. 4,604,424 (Cole) contains polydiorganosiloxanes, hardeners, platinum-containing hydrosilation catalysts, and zinc oxide and magnesium oxide fillers, the particle size of which is substantially all filler particles of 325 mesh. It is about the size that passes through a screen, and the average particle size of this filler is described as a thermally conductive silicone elastomer of less than 10 mu m.

The filler consists of 50 to 90% by weight of zinc oxide (ZnO ₂ ) and 10 to 50% by weight of magnesium oxide (MgO) relative to the weight of the filler.

Other fillers (up to 40% by weight) include aluminum oxide (Al ₂ O ₃ ), ferric oxide and carbon black.

Cured elastomers are known to withstand erosion by abrasive materials to a greater extent than compositions containing aluminum oxide as the sole filler.

Nevertheless, such shear mixing has been used to break up the particle size and geometry of the conductive filler with the intention of increasing the thermal conductivity throughout the resin to be dispersed.

Improvement of the various mixing and processing techniques can be commercially applied in a variety of industries, such as electrical, electronics, medical, and environment, and resin-based compositions having high thermal conductivity of high efficiency under low voltage driving are still subject to development. .

Accordingly, there is a need for planar heating elements having better thermal conductivity without compromising both the mechanical properties of the composition or the mechanical properties of the cured reaction product.

The present invention has been proposed to solve the problems of the prior art and the technical problem that has been requested from the past, the present invention is a carbon nanotube having a small amount of high electrical conductivity and thermal conductivity to various substrates such as resins, paints and adhesives It is an object of the present invention to provide a planar heating element using carbon nanotubes having a high thermal conductivity having excellent thermal uniformity and easy to be formed by addition, and a method of manufacturing the same.

The manufacturing method of the present invention for achieving the above object comprises a first step of forming a heat generating unit by mixing and dispersing carbon nanotubes having an average length of several tens to several hundred μm at a constant mass ratio with respect to the polymer resin substrate; A second step of forming a sheet-shaped electrode part with an electrical resistance in the range of 1 to 10 ⁵ Ωcm in the heat generating part mixed and dispersed in the first step; And a third step of attaching an insulating portion having high conductivity to the heat generating portion.

      A heat generating part formed of a polymer resin material mixed with carbon nanotubes by such a process; An electrode portion having a large area on the surface of the heat generating portion; The heat generating unit is to obtain a planar heating element composed of an insulating portion for preventing the short circuit caused by contact with the outside.

    Hereinafter, the overall configuration of the present invention and specific effects obtained therefrom will be described in detail with reference to the accompanying drawings.

      The present inventors have come to produce the planar heating element of the present invention by using a phenomenon in which the electrical conductivity of the heat generating part 100 is remarkably increased by the addition of a small amount of carbon nanotubes 110.

     In other words, when dispersing conventional conductive carbon, especially graphite, carbon black, and activated carbon / fiber, in polymer resins, an excess of 50% by weight or more of carbon particles must be added to obtain a desired resistance and exothermic effect. The mechanical strength decreases with difficulty, but the carbon nanotubes used in the present invention have sufficient electrical and thermal conductivity even with the addition of a small amount of 10 wt% or less relative to the resin substrate. Along with formability, mechanical strength also does not decrease.

     In general, carbon nanotubes are generally in the range of several tens to several tens of micrometers, and have a structure that is anisotropic so that their lengths reach tens to hundreds of micrometers.

According to these structural characteristics, it is also mechanically strong (about 100 times of iron) and has excellent chemical stability, and also has excellent thermal conductivity of 1,800 ~ 6,000W / mK as it has semiconducting properties with electric resistance of 10 ^-1 ~ 10 ^-4 . It is hollow and hollow, and has a lower density than graphite or carbon fiber, which is a common carbon material.

     In addition, the ratio of length to diameter (L / R) is high (100 to 10000), and when dispersed in a polymer resin, a small amount is added to form a network structure with each other, so that insulation due to short circuit and disconnection does not occur. Has conductivity.

     The manufacturing process of the present invention using the carbon nanotubes 110 having these characteristics is as follows.

That is, the first step 10 of forming a heat generating part 100 by mixing and dispersing carbon nanotubes having an average length of several tens to hundreds of micrometers in a constant mass ratio with respect to the polymer resin substrate 120; A second step (20) of forming a sheet-shaped electrode part (200) by mixing and dispersing in the first step so that the electrical resistance is in the range of 1 to 10 ⁵ Ωcm; And a third process 30 of attaching the heat transfer part 300 having high conductivity to the heat generating part 100.

      The planar heating element of the present invention manufactured by such a process, as illustrated in the drawings, the heat generating part 100 and the heat generating part 100 formed of a polymer resin substrate 120 mixed with carbon nanotubes 110. The electrode portion 200 having a large area on the surface of the, and the heat generating portion 100 is composed of an insulating portion 300 to prevent the short circuit caused by contact with the outside.

     The manufacturing method of the present invention is described in detail in the following examples, but the scope of the present invention is not limited to the examples.

Example 1

     Carbon nanotubes 110 were obtained by thermal decomposition of hydrocarbons of metal catalysts and gases, the length of which is several tens to several hundred micrometers, the diameter of which is 20 ~ 50nm.

When the weight of the composite in which carbon nanotubes and polyester were mixed was 100, the amount of carbon nanotubes was 0.5 and polyester was 99.5, which was dispersed and mixed.

Example 2

Carbon nanotubes 110 used are the same as in Example 1.

When the weight of the composite in which carbon nanotubes and polyester were mixed was 100, the amount of carbon nanotubes was dispersed in 1, polyester 99, and mixed.

Example 3

Carbon nanotubes 110 used are the same as in Example 1.

When the weight of the composite in which carbon nanotubes and polyester were mixed was 100, the amount of carbon nanotubes was 3 and polyester was dispersed and mixed.

Example 4

Carbon nanotubes 110 used are the same as in Example 1.

When the weight of the composite in which the carbon nanotubes and the polyester are mixed is 100, the amount of the carbon nanotubes is 5 and the polyester is 95, which is dispersed and mixed.

Example 5

     Carbon nanotubes 110 used are the same as in Example 1.

When the weight of the composite in which the carbon nanotubes and the polyester are mixed is 100, the amount of the carbon nanotubes is 10 and the polyester is 90 to disperse and mix.

Example 6

Carbon nanotubes 110 used are the same as in Example 1.

When the weight of the composite in which carbon nanotubes and polyester were mixed was 100, the amount of carbon nanotubes was 20 and polyester 80 was dispersed and mixed.

[Comparative Example]

Compared to the above embodiment, the planar heating element was manufactured by using only 100% by weight of polyester resin without adding carbon nanotubes.

Table 1 Electrical Resistance Values According to Examples

 Electric resistance value (Ω㎝)    Comparative example 2 x 10 ⁸ or more    Example 1 5 × 10 ⁵    Example 2 1 × 10 ⁴    Example 3 2 × 10 ³    Example 4 8 × 10 ²    Example 5 2 × 10 ²    Example 6         10

Measurements were made at 2 points using a HP2000 multmeter, and the samples were 2 cm long and 1 cm wide.

Those skilled in the art to which the present invention pertains will be capable of various applications and modifications within the scope of the present invention based on the above contents, and such uses and modifications are within the scope of the present invention.

As described above, according to the present invention, a planar heating element using carbon nanotubes can obtain a planar heating element that exhibits a high electrical conductivity even in a small amount compared to a conventional heating element.

In addition, it can be manufactured in any shape, excellent molding, and does not lower the mechanical properties.

In addition, carbon nanotubes have much higher thermal conductivity than other materials, such as 1,800 ~ 6,000W / mk, so the surface heating element made of carbon nanotubes shows excellent thermal conductivity even under low voltage driving due to the small amount of carbon nanotubes. It is easy to commercialize.

Claims (4)

A first step of forming a heat generating part by mixing and dispersing carbon nanotubes having an average length of several tens to hundreds of micrometers at a constant mass ratio with respect to the polymer resin substrate; A second step of forming a sheet-shaped electrode part with an electrical resistance of the heat generating part mixed and dispersed in the first step in a range of 1 to 10 ⁵ Ωcm; A method of manufacturing a planar heating element using carbon nanotubes manufactured by a third step of attaching an insulating portion having high conductivity to the heat generating portion. The method of manufacturing a planar heating element using carbon nanotubes according to claim 1, wherein the carbon nanotubes added in the resin base material are formed into a single wall, a double wall, and a multilayer wall. The method of claim 1, wherein the mixing ratio of the carbon nanotubes with the polymer resin substrate is 0.5% to 20% by weight of the total weight.       A heating part 100 formed of a polymer resin material mixed with carbon nanotubes; An electrode unit 200 having a large area on the surface of the heat generating unit 100; Planar heating element using carbon nanotubes, characterized in that the heat generating portion 100 is composed of an insulating portion 300 for preventing the short circuit caused by contact with the outside.

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