KR100665705B1 - Electric conductive metal fiber and functional compound using seat type heater and preparing thereof - Google Patents

Abstract

The present invention relates to a sheet-type heating element comprising a nonwoven fabric heating element in which a conductive metal fiber and a non-conductive fiber are mixed as a substrate and bound by a binder, and carbon powder, ocher powder, charcoal, jade, and tourmaline, which are selectively applied to the heating element. Anti-arc on the radiator and the heating element or both sides of the heating element coated with a mixture consisting of at least one functional compound selected from the group consisting of: a binder binding the functional compound, a diluent for improving workability, and a dispersant for dispersing distilled water and a functional compound; Provided is a sheet-type heating element using a conductive metal fiber and a functional compound including an insulating coating layer coated with a laminating material on both sides of the conductive wire and the heating element formed after the treatment, and a method of manufacturing the same.

Planar heating element, conductive metal fiber, arc prevention treatment, far infrared heating sheet, anion, superconducting heating element

Description

Sheet-type heating element using conductive metal fiber and functional compound and manufacturing method thereof {ELECTRIC CONDUCTIVE METAL FIBER AND FUNCTIONAL COMPOUND USING SEAT TYPE HEATER AND PREPARING THEREOF}             

1 is a process chart of the manufacturing method according to an embodiment of the present invention.

Figure 2 is a surface view of the heating element according to an embodiment of the present invention.

Figure 3 is a surface view of the sheet-like heating element coated on the radiator according to an embodiment of the present invention.

Figure 4 is a surface view of the sheet-like heating element is a band-shaped pattern applied to the radiator according to an embodiment of the present invention.

The present invention relates to a sheet-like heating element using a conductive metal fiber and a method for manufacturing the same, and more particularly, to a durable sheet-like heating element having a uniformity of resistance and uniformity of temperature distribution using a conductive microfiber.

Conventional heating elements are widely used as heating elements for residential and mall floor heating, electric mats, ondol beds, etc., because they are convenient to use and can provide comfortable heating without contaminating indoor air, unlike oil or gas heating. In recent years, the heating element is expanding its use as a heating element not only residential heating, but also agricultural, industrial, and medical.

As the heat generating source of the heating element, a linear heating element using nichrome wire and a sheet-type heating element using carbon fiber and carbon powder are roughly classified. In the case of the linear heating element, since the nichrome wire is dissipated by one strand of nichrome wire, the nichrome wire is disconnected due to rapid temperature rise and moisture corrosion, and the life of the heating element is exhausted. There is a disadvantage that the heat distribution cannot be obtained. In addition, a heating element made of carbon fiber and carbon powder may cause a decrease in heat generation capacity and shorten the life of the heating element due to deterioration of the conductive carbon compound due to heat of resistance and oxidation. In order to produce a heating element through impregnation or printing process, the carbon film thickness is constant, but there is a problem in that one or more pairs of electrodes are used to manufacture a high temperature heating element because electrical conductivity cannot be lowered.

Among many attempts to solve this problem, Korean Unexamined Patent Publication No. 1987-11498 discloses a thermosetting resin, a resin of a curing agent and a thickener so that the whole surface of the sheet is uniformly generated and a sheet-type heating element that generates a predetermined amount of heat can be produced with good reproducibility. A mixture in which the conductive fibers are mixed and dispersed in a composition is laminated on a sheet-like material that can impregnate the resin composition, and the resin composition further includes a sheet-like material that can impregnate the resin composition into the layer of the mixture of sheet-like active material. A method for producing a sheet-like heating element that is laminated and heat cured in a pressurized state has been proposed.

The method of manufacturing the sheet-like heating element is a conventional sheet-like heating element is made of a sheet-like molding material from a conductive fiber and a thermosetting resin in a synthetic resin and then pressurized heating to form a method in which the conductive fiber is moved when pressed, the entire surface does not evenly generate heat, Although there is an improvement in the disadvantage that it does not generate a predetermined amount of heat due to poor reproducibility, it does not take into consideration the durability reduction due to oxidation and deterioration of the conductive carbon fiber or the control aspect of the electrical conductivity, and because the heating material itself is a hard type, The choice of laminating materials was not free, and the use of thermosetting resins did not allow for the reduction of production capacity and the increase of manufacturing cost.

In addition, Korean Patent Laid-Open Publication No. 2002-39608 discloses a sheet-like heating element using a woven product using carbon fiber as a weft or warp yarn and a metal yarn having heat transfer characteristics as a warp or weft yarn as a radiation layer. However, the weaving of the metal yarn in the above method is not technically easy and excessive manufacturing cost is generated therein, and the heat generation characteristics and durability according to the density form of the fabric form have not been examined.

On the other hand, the sheet-like heating element may not be perfect for overheating due to contact resistance of the electrode portion, and there is a problem of fire risk and durability deterioration due to an increase in temperature due to arc heat at the contact surface due to an increase in contact resistance between the heating element and the electrode wire. In addition, if an arc occurs, it may cause problems in the durability of the product, and various attempts have been made in terms of stability and durability of the sheet-type heating element. Korean Utility Model Utility Model No. 1987-15658 has electrode poles for power supply along both side portions, and transfers a conductive film to the outer surface of the insulating sheet of the sheet-type heating element in which the front and back surfaces are electrically insulated by the insulating sheet. A safety device for a sheet-type heating element has been proposed in which a coil end of a relay switch formed on a power supply line to the sheet-type heating element or a lead line of a temperature sensing line is connected to all the films, and the other end of the coil is connected to each of the power supply lines through a diode. The above-described apparatus can achieve a predetermined purpose, but a separate device must be added to the sheet-shaped heating element, and local temperature rise can be detected, but high heat generation due to an increase in local resistance can not be detected. The essential problem cannot be solved. In particular, when the sheet-type heating element is embedded in the floor, there is a problem in construction and difficult to repair the problem, a fundamental structural solution of the sheet-type heating element is desired.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a sheet-type heating element having excellent heat generating performance and low temperature uniformity and physical property change by using a conductive metal fiber and a functional compound.

Another object of the present invention is to provide a sheet-like heating element that is safe for the human body without the generation of electromagnetic radiation to maximize the amount of far-infrared radiation and anion by introducing a beneficial component to the human body.

Still another object of the present invention is to provide a sheet-type heating element having an arc prevention treatment on the conducting wire of the sheet-type heating element to secure the safety of the energization on the heating element and to improve durability.

Still another object of the present invention is to provide a method of manufacturing a sheet-type heating element, in which conductive metal fibers are oriented and uniformly distributed to ensure optimal heating efficiency and current safety.

Still another object of the present invention is to provide a method of manufacturing a sheet-type heating element that maximizes energy saving side by using thermal efficiency and thermal feeling felt by a human body by simultaneously providing a high temperature heating part and a low temperature heating part to a heating element.

In order to achieve the above object, the present invention provides a sheet-type heating element,

A functional compound selected from the group consisting of carbon powder, ocher powder, charcoal, jade, and tourmaline, which is a nonwoven fabric heating element mixed with a conductive metal fiber and a non-conductive fiber as a substrate and bound by a binder, and optionally applied to the heating element. And a radiator coated with a mixture consisting of a binder for binding the functional compound, a diluent for improving workability, and a dispersant for dispersing distilled water and a functional compound, and a conductor and a heating element formed after arc-treating treatment on both sides of the heating element or the radiator. It provides a sheet-type heating element using a conductive metal fiber and a functional compound comprising an insulating coating layer coated with a laminating material on both sides of the.

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In another aspect, the present invention provides a method for producing a sheet-like heating element, the other surface step of dividing the aggregated conductive fibers and non-conductive fibers into a fiber individual, and the mixed fiber step so that each of the other surface fibers are random distribution, and the mixed fiber and the non-fiber A heating element forming step comprising a web forming step of manufacturing the malleable fibers in a web form, and a web bonding step of bonding the formed web into a sheet form on a face; A heat treatment step for preventing the formed heating element from being thermally deformed at a high temperature of 200 ° C. or more; A radiator forming step of applying a mixture of functional compounds, distilled water, binders, dispersants, and diluents, optionally selected from the group consisting of ocher powder, carbon powder, charcoal, jade, and tourmaline to the formed heating element; An arc preventing process for imparting stability of contact portions to both side surfaces of the formed heating element or radiator; And a wire is introduced on both sides and provides a method for producing a sheet-type heating element using a conductive metal fiber and a functional compound comprising an insulating coating step of coating both sides of the heating element or the radiator with an insulating film.

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In another aspect, the present invention provides a sheet-like heating element using a conductive metal fiber and a functional compound produced by the above production method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, it should be noted that in the drawings, the same components or parts denote the same reference numerals as much as possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

1 is a process chart showing the manufacturing process of the sheet-like heating element according to an embodiment of the present invention, Figure 2 is a schematic diagram of the manufacturing state of the heating element.

The conductive metal fibers and the non-conductive fibers are bonded to a binder to form a heating element forming step 110 to form a fibrous sheet. The heating element forming step 110 is the other surface step 112 for dividing the aggregated conductive fibers and non-conductive fibers into a fiber object, and the blended step 114 so that each of the other surface fiber is a random distribution, and the mixed conductive Web forming step 116 for producing fibers and other fibers in the form of a web (web), and a web bonding step 118 for combining the formed web in the form of a sheet on the face. 20 to 60% by weight of the conductive fibers, 40 to 80% by weight of the non-conductive fibers, it is preferable that the binder is bonded 5 to 10% by weight. In addition, the fiber mixed with the other surface is preferable to maintain the culture in one direction in terms of the exothermic characteristics, Figure 2 shows that the alignment in the X-axis and in the present invention, the orientation is more preferably made of X.

.cm, 내열성(42℃에서 10% 강도저하), 인장강도 106 내지 140 kg/mm² 정도의 도전성 섬유가 바람직하다. 특히 시트형 발열체의 발열특성은 도전성 금속사의 함량과 형상에 많은 영향을 받으므로 섬도 5 내지 10㎛, 길이 10 내지 20mm인 극세사가 보다 바람직하며, 상기 비도전성 섬유로서 유리섬유, 아라미드섬유,(또는 합성섬유로서 폴리에스테르 또는 펄프)와의 혼합성이 양호해진다. The conductive metal fiber used in the present invention does not deteriorate and oxidize even at high temperature, and smoothly contacts between adjacent yarns so that uniform resistance and uniform temperature expression can be realized, and there is no deterioration and heat resistance and heat transfer characteristics. It is preferred that it is excellent and can withstand up to 1150 ℃ in fibrous form and there is no change in physical properties over time. Therefore, the conductive fiber used for the sheet-like heating element according to the present invention is preferably a fine metal yarn of 5 to 15 ㎛ fineness, 5 to 50 mm in length and has an electrical resistivity of 72 to 100

.cm, heat resistance (10% strength reduction at 42 DEG C), and conductive fibers having a tensile strength of about 106 to 140 kg / mm ² are preferable. In particular, since the heat generation characteristics of the sheet-like heating element are greatly influenced by the content and shape of the conductive metal yarn, microfibers having a fineness of 5 to 10 μm and a length of 10 to 20 mm are more preferable, and as the non-conductive fiber, glass fiber, aramid fiber, or synthetic Good blendability with polyester or pulp) as fibers.

The binder is also made into a sheet on a nonwoven fabric by bonding an acrylic or polyester resin binder onto a web. Table 1 is a heating element table according to a preferred embodiment of the present invention.

division material Weight ratio (%) Role Ultra-fine conductive metal fiber Stainless, Cu, Ag, AL etc 20-60% Exothermic action by electric resistance Non-conductive fiber Glass and Rayon Fiber Aramid Fiber, Pulp, Synthetic Fiber (Polyester) 40-80% Intermediate material produced in fiber form by mixing with metal yarn bookbinder Acrylic / polyester resins, epoxy, urethane, polyolefin resins 5-10% Bonding material of conductive fiber and non-conductive fiber

The formed heating element is subjected to a heat treatment step 120 to prevent thermal deformation at a high temperature of 200 ℃ moving this step can be used because a conventional heat treatment method will not be described in detail.

A step of selectively forming a radiator and a secondary heating layer on or above the heating element that has undergone the heat treatment step 120 may be performed. The heating element is a binder such as 20 to 40% by weight of functional compounds selected from the group consisting of ocher powder, carbon powder, charcoal, jade, tourmaline, 50 to 70% by weight of distilled water, acrylic resin, polyester resin and the like. The heating element may be impregnated or printed on top of the heating element in a mixture of about 40% by weight to about 1% by weight, 1 to 5% by weight of the dispersant, and 1 to 3% of the diluent. Preferably, it can be laminated by screen printing. The functional compound is a means for increasing the far-infrared rays and / or anion radiation and the exothermic effect, which is beneficial to the human body, and using a fine powder having a particle size of 2 to 100 μm and being mixed with the binder at 21 to 70% by weight as a whole, a high temperature heating part and a low temperature. It is possible to have a heat generating portion at the same time. In the present invention, the radiator may itself serve to radiate beneficial components to the human body, and may serve as a secondary heating element depending on the type and content of the functional compound (particularly, components of carbon powder, etc.). do.

3 and 4 is a laminate of the radiator on the heating element as a preferred embodiment of the present invention. The substrate 210 composed of the synthetic fiber (particularly polyester), glass fiber, aramid fiber or pulp is mixed with the conductive metal fiber 220 to form the heating element 200 in the form of a nonwoven fabric (web form), and the heating element ( 200, the radiator 310 or 410 of the mixture may be stacked on the top. Figure 3 shows that the radiator 310 is applied in the pattern of bands at regular intervals, the ratio of the coated portion and the non-coated portion is preferably about 1: 1. In addition, Figure 4 shows that the radiator 410 is applied to the entire length of the heating element (200). Which method to adopt in the coating method is a matter that can be selectively considered in terms of energy consumption. Components of the radiator according to an embodiment of the present invention are shown in Table 2.

division material Weight ratio (%) Role Functional compound Activated carbon, ocher, charcoal, carbon powder 20-70% Far Infrared / Anion Radiation bookbinder Acrylic, polyester, epoxy, polypropylene resin 5-40% Binders of Functional Compounds Distilled water 50 -70% Thinner Isopropyl alcohol, methyl ethyl ketone 1-3% Improve workability Dispersant High Polymerization Alkyl Ammonium 1-5% For dispersing functional compounds

The heating element that has undergone the heating element forming step 110 or the radiator forming step 130 passes through the arc prevention treatment step 130. The purpose of this step is to prevent the generation of resistance heat (contact resistance) by forming a high current density at the power supply contact area, and the movement and flexibility due to the electrode thickness in μm will inhibit the flow of electricity. It is to provide electricity safety to maintain the current, and to prevent the formation of metal oxide by the contact and the current-carrying adhesive on the surface of the copper foil and to improve the contact force to reduce the friction caused by heat or movement to give the stability of the contact site. In the present invention, the arc protection method may be implemented by various methods. By lowering the resistance value of the contact part by the conductive paste, the concentrated resistance and the boundary resistance between the electrode wire and the heating element are lowered, and the copper foil is energized and the contact lubricant is considered in consideration of the fluidity and the metal oxide film formation due to the characteristics of the flexible sheet type heating element. By impregnating with and simultaneously using a resin laminated on the electrode to reduce the contact resistance by improving the adhesion with the insulating film can be prevented arc generation by contact resistance.

The heating element passed through the arc prevention treatment step 130 is introduced into the wires on both sides and finally undergoes an insulating coating step (140). In order to improve the insulation performance, both the front and rear surfaces of the heating element 200 are coated. As the insulating film, a PET-based resin may be used, and MLB laminating may be used at high temperature. At this time, the copper foil (Copper Foil) used as the wire as described above uses a material laminated with a resin on one surface.

Example 1 Exothermic Performance

The heat generation performance of the carbon-side heating element and the sheet-like heating element according to the present invention is compared.

Exam conditions Item Carbon face heating element Sheet-type heating element Conductive Material Ratio 20% 20% Heating element standard 500 X 1000 500 X 1000 Voltage (V) 110 V 110 V Room temperature (℃) 20 20

As a result of testing both heating elements under the above conditions, the sheet-type heating element according to the present invention has a high heating temperature of about 40%, which can lower the operating voltage based on the same temperature as compared with the carbon-type heating element, thereby providing a more stable sheet-type heating element. It can be done. Specific results are shown in the table below.

Item Carbon Sheet Type Heating Element Sheet-type heating element Electrode resistance (??) 35 21 Current (A) 4.1 5.13 Power Consumption (W) 373 604 Exothermic temperature (??) 64-70 93-100

Example 2 Indoor air rise and heating element surface temperature measurement

It is a data measured value according to the increase of indoor air temperature of carbon heating element and this heating element. As shown in the following table, the rise of indoor air due to heat generation was measured to be the same, and the bottom surface temperature of the present heating element was about 5 ° C higher. This is because the heat generating unit using the conductive metal fiber is divided into a high temperature heating unit and a low temperature heating unit, so that the surface temperature is higher than that of the carbon heating element having the same power consumption.

Item Carbon heating element Heating element How to measure exam                                                  Condition Indoor area (m ³ ) 3W X 3L X 2.4H 3W X 3L X 2.4H Uptime (H) 2 2 Continuous operation Power Consumption (kw / h) 1.8 1.8 Power meter Voltage (V) 220 220 Outdoor temperature (℃) -2.6 -2.6 2-channel atmospheric thermometer Room temperature before operation (℃) 15 15 2-channel atmospheric thermometer result Room temperature Floor surface temperature 32-35 (℃) 38-40 (℃) 6 channels, contact H = 1.9m temperature 22-24 (℃) 22-24 (℃) 6 channels, standby

Example 3-Measurement of exothermic temperature and resistance value according to test change

As a result, the heating element of the present invention had a resistance of about 54% and an exotherm temperature of 25-40%. This means that a high temperature heating element can be manufactured even at a low voltage, and the heating temperature can be freely selected regardless of the width of the heating element.

Voltage 48V AC division Length (cm) Taso heating element Heating element How to measure Resistance (Ω) Exothermic temperature) Resistance (Ω) Exothermic temperature (℃) Front pole distance (cm) 20     50 33 70-74 18 97-100 Contact Thermometer, Multi Testor 25 42 54-56 23 77-79 30 50 43-45 27 60-63 35 58 39-40 32 52-54 40 67 35-36 36 44-46 45 75 32 41 40-43 50 83 30 45 37-38 55 92 28 50 35-36 60 100 - 54 33-34 65 108 - 59 31

Example 6-Measurement of resistance value and exothermic temperature after coating the radiator to the heating element linearly

The exothermic temperature was measured at the high temperature heating part treated with carbon linearly, and the temperature rise was slightly increased even at the low temperature heating part not treated with carbon.

Item Heating element Emitter High temperature heating part Low temperature heating part Conductive Material Ratio Conductive Metal Fiber (20%) Conductive Metal Fiber (20%) + Carbon Powder (15%) Conductive Metal Fiber (20%) Heating element standard 500x2000mm 500x2000mm Voltage (V) 110 110 Electrode resistance (Ω) 37 14 Current (A) 3.1 8.4 Power Consumption (W) 354 967 Actual temperature (℃) 45-50 89-92 53-57 Room temperature (℃) 20 20

Example 5

Test condition: Polar copper foil is placed on heating element and coated with laminating PET film

Exothermic Temperature Measurement Condition:

1.Horizontal: Place the heating element on the floor and measure the temperature of both poles

2. Vertical: Measure the temperature of both poles by raising the heating element

3. Vertical + cloth finish: Measure the temperature of the pole after putting the heating element up and keeping warm with cloth

result Pole line type Measuring point Temperature change 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 Arc generation Copper foil (arc prevention) #One 18.4 45.4 47.1 78.8 85.8 82.3 100 101.7 X #2 18.2 43.4 44 79.6 84.8 80.1 101.6 103.1 X Copper foil + silver paste #One 18.3 45.4 46.0 80.1 86.4 87.2 112.4 113.8 X #2 18.4 44.8 48.2 79.7 87.5 89.4 105.1 109.1 X Copper Tape (Conductive) #One 18 46 44.9 82.3 91.5 91.9 122.3 122.8 O #2 17.6 45.2 44.7 73.9 83.7 84.3 115.5 115.4 O Copper foil #One 17.8 69.5 65.9 106.3 150.1 152.2 - - O #2 18 64.6 66.4 102 124.2 128.6 - - O Room temperature 22 48.9 20.2 21.8 21.7 23.7 24.5 Exam conditions Horizontal Perpendicular Vertical + Cloth Finish

The heating element using the copper foil and the copper tape without the arc protection treatment did not generate the arc at the beginning, but it was measured that the arc occurred due to the contact resistance caused by the high potential difference at the contact point of the electrode line when it was operated for a long time. The phenomenon was also found. As a result, if the arc prevention treatment is performed on the pole of the heating element in which the arc is generated or in progress, the arc does not occur.

Example 6

Unlike Example 5, the electrode member is placed on the heating element and partially fixed with an adhesive tape to maximize the contact resistance.

1. When only copper foil is used for heating element

At the same time as the power was supplied, an arc was generated. At this time, in order to reduce the contact resistance, an object of insulating material was placed and brought into close contact, and arc generation was significantly reduced, but arc generation continued as time passed. The object of the insulating material was removed and subjected to arc prevention treatment for the third measurement. As a result, there was no arc and the exothermic temperature of the electrode wire was also measured below 48 ℃.

2. When copper tape is used for heating element

There was no arcing at the same time as the power supply, but the heating temperature of the pole was measured at 55 ℃, and the arc occurred after about 1 day.

3. When using arc-treated copper foil

After 1 day of power supply and after 3 days, there was a temperature increase of about 10% to 45 ° C and 50 ° C, but this is presumed to be the result of the increase in the temperature of the copper foil due to the conduction heat generated from the heating element. It was judged that there was no sign of arcing.

4. When copper foil is used after printing conductive paste on heating element

Initially, there was no arcing as in the anti-arc treatment, but it was measured that some specimens generate arcing when deforming the copper foil or applying external force such as friction or bending.

As described above, the sheet-type heating element according to the embodiment of the present invention has an effect of excellent heat generation performance and low temperature uniformity and physical property change by using conductive fibers. In addition, the radiator formed with carbon powder, tourmaline, ocher, etc. together forms an additional heat generation function and emits far-infrared / anion ions, which are beneficial to the human body. There are advantages to it.

In addition, by introducing the alignment structure of the fibers of the heating element and by improving the orientation has the effect of strengthening the heat generation performance by reinforcing the electrical conductivity.

In addition, the arc-preventing treatment of the sheet-like heating element can contribute to the prevention of fire and the durability of the product due to the arc generation, it is effective to secure the energization stability and prevent power loss.                     

In addition, by applying the functional mixture in the band-like pattern of a certain interval on the heating element has an excellent effect on the thermal effect and power consumption of the human body.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

Claims (12)

In the sheet heating element, A nonwoven heating element in which conductive metal fibers and non-conductive fibers are mixed as a substrate and bound by a binder; A functional compound selected from the group consisting of carbon powder, ocher powder, charcoal, jade, and tourmaline and a binder for binding the functional compound and a diluent for improving workability, and a dispersant for dispersing distilled water and a functional compound applied to a heating element A radiator coated with a mixture consisting of; Conductive wires formed after arc-protection treatment on both sides of the heating element or the radiator; Nonwoven heating element characterized in that it comprises an insulating coating layer coated with a laminating material on both sides of the heating element. delete delete delete delete In the manufacturing method of the sheet-like heating element, The other surface step of dividing the aggregated conductive fibers and the non-conductive fibers into a fiber individual, and the interweaving step so that each of the masked fibers has a random distribution, and the web forming step of manufacturing the mixed fibers and the non-conductive fibers in a web form; A heating element forming step comprising a web bonding step of bonding the formed web into a sheet form on a plane; A heat treatment step for preventing the formed heating element from being thermally deformed at a high temperature of 200 ° C. or more; A radiator forming step of applying a mixture of functional compounds, distilled water, binders, dispersants, and diluents, optionally selected from the group consisting of ocher powder, carbon powder, charcoal, jade, and tourmaline to the formed heating element; An arc preventing process for imparting stability of contact portions to both side surfaces of the formed heating element or radiator; And An electric wire is introduced on both sides and a method of manufacturing a sheet-type heating element using a conductive metal fiber and a functional compound comprising an insulating coating step of coating both sides of the heating element or the radiator with an insulating film. delete delete delete delete delete A sheet-type heating element using a conductive metal fiber and a functional compound produced by the manufacturing method of claim 6.

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