KR20030010826A - Heating element using conducting polymer film - Google Patents

Abstract

PURPOSE: A plane heater using a conductive heater is provided to prevent an electric shock and a leakage of electricity by forming a conductive polymer film operated with a low resistance and a low voltage. CONSTITUTION: A conductive polymer such as polyaniline of 0.7g is melt into NMP(N-methyl-2-pyrrolidone) of 0.01 liter(100). The mixture of the polyaniline and NMP is filtered by a cotton filter and impurities are removed from the mixture(200). The mixture is filled into a groove of a molding substrate and a polyaniline film of 100mmLx100mmWx0.1mmH is formed by evaporating the NMP under temperature of 70 degrees centigrade(300). The polyaniline film of 100mmLx100mmWx0.1mmH is dipped into hydrochloric acid solution of 1M in order to dope hydrogen ions(400). A plane heater unit is formed by adhering an electrode ribbon and an electric contact on the polyaniline film(500). A post-process is performed(600).

Description

Planar heating element using conductive polymers {HEATING ELEMENT USING CONDUCTING POLYMER FILM}

The present invention relates to a planar heating element using a conductive polymer, and more particularly, to prepare a conductive polymer film having low resistance using a conductive polymer, in particular polyaniline and its derivatives and / or polypyrrole and its derivatives, and an electrode on the conductive polymer film. By forming a belt and an electrical contact, by applying a DC power supply to the electrical contact, it is possible to operate at a low voltage, reduce the risk of electric shock and short circuit, and after a certain time to reach the final heating temperature and the heat generation temperature is no longer The present invention relates to a planar heating element using a conductive polymer that does not require an overheat prevention circuit.

Korean Unexamined Patent Publication No. 1996-17741 (Application No. 10-1994-39964, Prior Art 1) discloses a technique for manufacturing a polyaniline film and a composite, and Republic of Korea Patent Publication No. 1999-68286 (Application No. 10 -1999-6126, prior art 2) discloses a technique for a self-regulating planar heating element film and a method of manufacturing the same.

In the prior art 1, in preparing a conductive polyaniline, an aniline is oxidized in the presence of a positive asset and an oxidizing agent to prepare a polyaniline doped with a positive asset, and the polyaniline obtained by washing the polyaniline with distilled water and methanol and then drying the organic aniline After mixing with a base, it is dissolved in a polar solvent to obtain a polyaniline solution, and the polyaniline solution is coated or cast to prepare a polyaniline film.

The prior art 2 is a first step of blending a polyolefin resin, a raw material of carbon, graphite and a resin stabilizer in a powder state, and melt-mixing the raw material of the blended powder at a temperature of 200 ° C. or lower, and sealing with a first extruder After extruding to the upper body, the second process of forming the raw material member solidified by the cooling process, the third process of cutting the solidified raw material member into a chip form by a cutter, and melting the compounding member of the cut chip form The fourth step of extruding in a thin strand form by a second extruder, and the raw material to be extruded is applied between the divided electrode strip, and the coated paper is laminated on the upper and lower surfaces of the electrode strip to which the raw material is applied, A fifth step of pressing by high temperature press roller, a sixth step of cooling the planar heating element film pressed at high temperature, and a seventh step of winding the cooled planar heating element film to complete the manufacturing process It characterized by that for producing a self-control type plane heater film.

However, the prior art 1 can be used for antistatic film, conductive film, electromagnetic wave shielding film and the like, but it is not easy to use as a heating element because the resistance is larger than that of a common resistor (such as nichrome wire).

In addition, the prior art 2 uses a polyolefin, but the heat resistance temperature of the polyolefin is 200 ℃, so it is not suitable as a heating element, and melt-mixed and extruded into a rod-shaped body, the rod-shaped body is cut, secondary extrusion, compression roller There was a complicated problem in the manufacturing process, such as molding in the form of a film, cooling again.

The present invention is to solve the problems of the prior art as described above, while producing a planar heating element using a conductive polymer, the resistance is low, it is possible to operate at a low voltage, there is no risk of electric shock and short circuit, the final heat generation after a certain time Since the temperature is reached and the exothermic temperature does not increase any more, and it exhibits a constant temperature characteristic, there is no need for an overheat prevention circuit, and an object thereof is to provide a planar heating element having excellent heat resistance.

1 is a production process of the polyaniline powder according to the present invention.

Figure 2 is a flow chart showing the manufacturing process of the planar heating element in one embodiment according to the present invention.

3 is a conceptual diagram of a unit cell in which an electrode strip and an electrical contact are generated in one polyaniline film according to one embodiment of the present invention.

4 is a conceptual diagram of a planar heating element generated by connecting a plurality of unit cells of FIG. 3 in parallel in one embodiment according to the present invention;

Figure 5 is a graph of the current and heat generation (temperature) characteristics of the planar heating element produced by one embodiment according to the present invention over time.

Figure 6 is a graph of the current and heat generation (temperature) characteristics according to the current application time in the planar heating element manufactured by another embodiment according to the present invention.

*** Explanation of main parts of drawing ***

10. Conductive polymer film 20. Electrode strip 30. Electrical contacts

100. Dissolution step 200. Filtering step 300. Film creation step

400. Hydrogen ion doping step 500. Generating power supply step 600. Post-Work Step

The planar heating element using the conductive polymer according to the present invention, as the conductive polymer, using a dissolving step of dissolving the conductive polymer in a solvent; Injecting the conductive polymer solution produced in the dissolution step into the molding substrate, the film generation step of producing a conductive polymer film by removing the solvent contained in the conductive polymer solution; A doping step of doping the conductive polymer with hydrogen ions; It is prepared by a process comprising a step of generating a power supply for attaching an electrode strip to the end of the conductive polymer film and withdraw the electrical contact.

In the present invention, the doping step may be classified according to the specific order and method.

That is, in the present invention, the doping step may be a step of immersing the conductive polymer film in an acidic solution after preparing the conductive polymer film, or doping with hydrogen ions by spraying the acidic solution. In this case, since the hydrogen ions are doped only on the surface of the film after the conductive polymer film is formed when the doping time is not sufficient, the doping effect may be less. Therefore, the present invention provides another process for maximizing the doping effect.

That is, in the present invention, while dissolving the polymer in the dissolution step, an acid component may be additionally added to the solvent to dope the conductive polymer with hydrogen ions in the liquid phase.

In the present invention, the conductive polymer may use various kinds of chemical structures capable of flowing electrons to a certain extent in a polymer state, and particularly, polyaniline and its derivatives and / or polypyrrole and its derivatives.

In the present invention, the solvent is a solvent capable of dissolving the conductive polymer, in particular, NMP (N-methyl-2-pyrrolidone), m-cresol, p-cresol, 3-ethylphenol, 2-Cl-phenol, 2-F -phenol, chloroform, DMF (dimethyl formamide), benzyl alcohol, 3-isopropylphenol, 2-OCH ₃ -4-CH ₃ -phenol, acetic acid, DMSO (dimethyl sulfoxide), o-chlorophenol, formic acid, acetic acid, dichloromethane , trifluoroacetic acid, benzene, or a mixture of two or more thereof.

In the present invention, as the dopant, a chemical capable of providing hydrogen ions may be used. Specifically, an acid such as HCl (hydrochloric acid), HCSA (camphorsulfonic acid), or HDBSA (dodecylbenzenesulfonic acid) may be used.

In the present invention, carbon powder may be added to lower the electric resistance value of the conductive polymer film to consume less power, and ceramic powder may be added to emit beneficial far infrared rays to the human body when the planar heating element according to the present invention generates heat. . At this time, the amount of these added is preferably 0.01 to 0.5 parts by weight based on the conductive polymer. If it is 0.01 parts by weight or less, the desired effect is minimally expressed, and if it is 0.5 parts by weight or more, there is a side effect of significantly lowering the physical properties of the film. The diameter of the powder particles may be in the range of 0.5 to 50 μm, and the average particle diameter is preferably 10 μm.

Carbon powder and / or ceramic powder may be added directly in the dissolution step so that the powder particles may be mixed with the conductive polymer and eventually mixed uniformly inside the film. In the film formation step, the polymer solution is added to the molding substrate. These powders may be uniformly dispersed on the surface of the injected solution so that the powder particles exist only on the surface.

As the far infrared ceramic powder, any known conventional far-infrared ray emission effect can be used, and specifically, an alumina powder, silicon carbide powder, alumina nitride powder or a mixture thereof can be used.

According to the present invention, when the carbon powder is uniformly distributed in the planar heating element, the electric resistance of the planar heating element is reduced, so that operation is possible even at a low voltage. Therefore, unlike the conventional planar heating element, it is possible to use a low voltage DC power supply. . Therefore, the planar heating element according to the present invention has no risk of electric shock even when disconnection or leakage.

If necessary, after the dissolution step, a filtering step may be added to filter the material not dissolved in the solvent.

In the present invention, it is preferable that a direct current power is applied to the electrical contact.

Hereinafter, the present invention will be described in detail with reference to Examples and Experimental Examples. However, these examples and experimental examples are for illustrative purposes only, and the present invention is not limited thereto.

Example 1 Synthesis and Doping of Polyaniline

(1) Synthesis of Polyaniline

1 shows a process of synthesizing polyaniline, which is one of the conductive polymers used in the present invention.

First, 80 ml (0.22 mol) of aniline was dissolved in 1,200 ml of 1 M HCl and cooled to 0 ° C., and 46 g (NH ₄ ) ₂ S ₂ O ₈ (oxidizing agent: K ₂ Cr ₂ O ₇ , KMnO ₄ , FeCl ₃ ) was dissolved in 800 mL of 1 M HCl and cooled to 0 ° C. The solution containing the oxidant was slowly added to the solution containing aniline and stirred for 90 minutes while stirring with a magnetic spoon. The reaction precipitate (42% protonated) was filtered using # 1 Whatman filter paper and washed with 5 L of 1M HCl until the filtrate was colorless. The filtered sample was added to 2000 ml 1 M HCl solution, stirred with a magnetic spoon and left for 15 hours, and filtered. In filtration, 1000 ml of 1 M HCl was used until the filtrate was completely colorless. The obtained sample (50% protonated) was again added to 2000 ml 0.1 M NH ₄ OH solution, stirred with a magnetic straw for 15 hours, filtered and dried in a drying tube connected to a vacuum line for 48 hours. Through the above process, a polyaniline emeraldine base sample was obtained.

In the present invention, the following experiment was performed by synthesizing the polyaniline, which is a conductive polymer, by the above method. However, the conductive polymer may be prepared and used by various methods other than the above method, or a commercially available polyaniline may be purchased and used.

Example 2 Preparation of Planar Heating Element

2 shows a manufacturing process of the planar heating element using the conductive polymer according to the present invention. In this embodiment, the doping method is adopted after film formation.

0.7 g of polyaniline obtained in (1) of Example 1 was dissolved until saturated in 0.01 L of NMP (dissolution step, 100), and then filtered through a filter pad to remove polyaniline and other impurities not dissolved in NMP solvent ( Filtering step, 200).

The polyaniline solution passed through the filtering step 200 is filled in a groove of a molding substrate having a flat groove (100 mmL × 100 mmW × 10 mmH) formed therein, and the temperature of 70 ° C. is applied to evaporate NMP to 100 mmL × 100 mmW × 0.1 mmH. A polyaniline film of size was obtained (film production step, 300).

The polyaniline film obtained through the film producing step 300 was immersed in 1M hydrochloric acid solution to dope hydrogen ions for 24 hours (hydrogen ion doping step, 400). After the doped film was dried, the electrode strip 20 and the electrical contact 30 were attached to the sock end of the polyaniline film 10 to prepare a planar heating element unit cell as shown in FIG. 3 (power supply generation step 500).

Post-operation step (600) is a step of processing the planar heating element produced by the present invention as a product to cover the outside according to the form of the final product such as electric blanket, electric blanket, car seat, hand stove, or Pointing to the work, such as covering the jangpan, when the present invention can be carried out including the post-work step (600).

Example 3 Preparation of Planar Heating Element Added with Carbon Powder and Ceramics Powder

In the dissolving step 100, a planar heating element to which carbon powder and far-infrared ceramic powder were added was prepared in the same manner as described in Examples 1 and 2, while adding 30 parts by weight of carbon powder and 15 parts by weight of far infrared ceramics powder to polyaniline. .

In this case, the carbon powder used was one having an average particle diameter of 10 μm, and the ceramic powder was composed of alumina, silicon carbide, and alumina nitride, and the average particle diameter was 10 μm.

Experimental Example: Investigation of characteristics of planar heating

DC voltage of 9 V was applied to the planar heating elements prepared in Examples 2 and 3, and the change of temperature and the change of current over time were examined (FIGS. 5 and 6). The size of the planar heating element used in the experiments of FIGS. 5 and 6 is W x L x t = 20 x 70 x 0.1 mm.

(1) Planar heating element using the sample of Example 2 as a raw material

Referring to FIG. 5, when a DC voltage of 9 V was applied at room temperature, a current of about 92 mA flowed, and the temperature gradually increased, and then increased to 50 ° C. after 1 minute. After that, the rate of temperature slowed down significantly, maintaining about 60 ° C., and the temperature rise did not occur anymore, indicating a saturated state (constant temperature characteristic). In addition, the current increased to 107 mA and started to decrease slightly after reaching 60 ° C. to maintain the current below 104 mA and the temperature at 60 ° C.

(2) Planar heating element using the sample of Example 3 as a raw material

Referring to FIG. 6, when a DC voltage of 9 V was applied at room temperature, a current of about 170 mA flowed, and the temperature increased gradually and increased to 53 ° C. after 1 minute. After that, the rate of increase of temperature was significantly slowed to maintain about 60 ° C. and no further temperature increase occurred, indicating a saturation state. In addition, the current increased to 180 mA and started to decrease slightly after reaching 60 ° C., keeping the current below 178 mA and the temperature at 60 ° C.

According to the experimental example described above, the planar heating element according to the present invention has a characteristic of maintaining a constant temperature (constant temperature characteristic) after the temperature reaches the final temperature (60 ° C.) to be obtained. Therefore, it was confirmed that the planar heating element according to the present invention does not require an overheating control circuit, and thus, the control device is simpler and can be used as a safer heat generating mechanism than the conventional planar heating element.

Since the planar heating element according to the present invention is movable even at low voltage, it may be manufactured in a small size (for example, a hand stove) to use a general AA type battery as a power source.

Planar heating element using the conductive polymer produced by the present invention as described above. Low resistance, low voltage operation, no risk of electric shock or short-circuit.After a certain time, the final heating temperature is reached and the heating temperature does not increase any longer. There is no need for a prevention circuit, and the effect is excellent in heat resistance.

Claims (10)

In the planar heating element using a conductive polymer, A dissolving step of dissolving the conductive polymer in a solvent; A film generation step of adding a conductive polymer solution generated in the dissolving step to a molding substrate and then removing a solvent contained in the conductive polymer solution to produce a conductive polymer film; A doping step of doping the conductive polymer with hydrogen ions; And Generating a power supply unit attaching an electrode strip to the end of the conductive polymer film and drawing an electrical contact; Planar heating element using a conductive polymer produced by a process comprising a. The method of claim 1, The doping step is a planar heating element using a conductive polymer, characterized in that the step of immersing the conductive polymer film in an acidic solution after the film generation step, or doping with hydrogen ions by spraying the acidic solution. The method of claim 1, The doping step is a planar heating element using a conductive polymer, characterized in that the addition of an acid component in the dissolving step to doping the conductive polymer in the liquid phase with hydrogen ions. The method of claim 1, The doping step is a planar heating element using a conductive polymer, characterized in that to dope the conductive polymer with hydrogen ions by immersing the conductive polymer in an acidic solution before the dissolution step. The method according to any one of claims 1 to 4, In the dissolving step, the planar heating element using a conductive polymer, characterized in that before or after dissolving the conductive polymer in a solvent, and further adding carbon powder and / or far infrared ceramic powder. The method according to any one of claims 1 to 4, The planar heating element using a conductive polymer, characterized in that the polymer solution is added to the molding substrate in the film production step and then carbon powder and / or far infrared ceramic powder is dispersed on the surface of the solution. The method according to any one of claims 1 to 4, The conductive polymer is a planar heating element using a conductive polymer, characterized in that any one or a mixture of two or more selected from the group consisting of polyaniline, polyaniline derivatives, polypyrrole and polypyrrole derivatives. The method according to any one of claims 1 to 4, The solvent is N-methyl-2-pyrrolidone (NMP), m-cresol, p-cresol, 3-ethylphenol, 2-Cl-phenol, 2-F-phenol, chloroform, dimethyl formamide (DMF), benzyl alcohol, 3 -isopropylphenol, 2-OCH ₃ -4-CH ₃ -phenol, acetic acid, dimethyl sulfoxide (DMSO), o-chlorophenol, formic acid, acetic acid, dichloromethane, trifluoroacetic acid, benzene any one or a mixture of two or more Planar heating element using a conductive polymer. The method according to any one of claims 1 to 4, After the dissolution step, Planar heating element using a conductive polymer further comprising a filtering step of filtering the material not dissolved in the solvent with a filter. The method according to any one of claims 1 to 4, Planar heating element using a conductive polymer, characterized in that the direct current is applied to the electrical contact.