KR20170133061A - Manufacturing method of flexible plane heating element and flexible plane heating element manufactured thereby - Google Patents

Abstract

The present invention relates to a flexible surface heating element. More specifically, the present invention relates to a method of manufacturing a flexible surface heating element and a flexible surface heating element manufactured by the method. Carbon fiber yarns are prepared by mixing iron oxide and carbon powder at an appropriate ratio to control the properties of reacting with electricity. So, heat characteristics are different from each other in the longitudinal and transverse directions of paper. Excellent flexibility can be realized by introducing a thermoplastic polyurethane layer on the top and bottom surfaces of the paper.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible surface heating element and a flexible surface heating element manufactured by the method.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible surface heating element, and more particularly, to a flexible surface heating element which comprises a carbon fiber yarn produced by mixing iron oxide and carbon powder at an appropriate ratio, And a flexible surface heat generating element produced by the method of producing a flat surface heating element and the method of manufacturing the flexible surface heating element which is excellent in flexibility by introducing a thermoplastic polyurethane layer to the upper and lower surfaces of the paper.

Background Art [0002] Conventional planar heating elements use a carbon fiber fabric or a graphite plate powder in which carbon fibers are dispersed in a pulp member, or a conductive polymer heating sheet in which carbon powder is dispersed. The structure of the surface heating element using the carbon fiber fabric and the conductive polymer sheet in which the carbon fiber is dispersed in the pulp member is composed of the upper and lower surface layers of the carbon fiber fabric or the conductive polymer sheet laminated with a polymer insulation layer for electrical insulation and waterproofing . Therefore, in a planar heating element using a carbon fiber fabric and a conductive polymer sheet, uniform heating can be performed on the entire surface of the heating element, which is caused by uneven temperature distribution due to heat generated only in the heating element, which is a problem of the linear heating element using a heating wire such as nichrome The discomfort can be solved.

In the carbon fiber fabric and the conductive polymer sheet, carbon fiber or carbon powder excellent in the far-infrared radiation characteristic is used as the conductive filler. The surface heating element using the carbon fiber fabric or the conductive polymer sheet is a contact It can be used not only as a heating method but also as a far-infrared radiation surface heating element which can be heated while maintaining a certain distance from an object.

Far Infrared Ray Radiation In order to increase the amount of far infrared radiation in a heating element, various far infrared ray emitting materials can be used together with carbon fiber or carbon powder. Particularly, Korean Patent No. 10-1201053 discloses a planar heating element including cubic or artificial diamond and carbon fiber. The cubic or artificial diamond is excellent in far-infrared radiation but is not electrically conductive. The electric conductivity of the carbon fiber is lowered and the heating efficiency is lowered. Therefore, in order to minimize deterioration of the heat-generating property, the amount of cubic zirconia or artificial diamond must be reduced, so that the effect of far-infrared radiation is not large.

If the electrical characteristics in the longitudinal direction or the transverse direction can be different from each other in one planar heating element, the temperature of the planar heating element can be controlled simply by selecting the power supply direction. In theory, the carbon fiber dispersed in the pulp member in the carbon fiber plane heating element can be imparted with a directionality, so that the heating characteristics in the species / sulfur direction of the plane heating element can be controlled differently. However, in practice, the pulp member acts as an obstacle when orienting the carbon fibers, which makes it difficult to orient the carbon fibers. Therefore, there is a limit to the technology of uniformly dispersing the carbon fibers in the pulp member at the same time as giving directionality.

Korean Patent No. 10-1201053

Therefore, a first object of the present invention to solve such problems is to provide a carbon fiber yarn by mixing iron oxide and carbon powder in an appropriate ratio to control the properties of the carbon fiber yarn to react with electricity, And a method of producing a flexible surface heating element having excellent flexibility by introducing a thermoplastic polyurethane layer on the upper and lower surfaces of the paper.

A second object of the present invention is to provide a flexible surface heating element manufactured by the method of manufacturing the flexible surface heating element.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to accomplish the above first object, the present invention provides a method for producing a nanoparticle powder, comprising mixing and pulverizing cubic and iron oxide to form a nanoparticle powder, about 1 to about 10 parts by weight of the nanoparticle powder, about 50 to about 80 Preparing a carbon fiber yarn having a thickness of about 1 m to about 20 m after melting the carbon fiber yarn, mixing the carbon fiber yarn with the paper pulp solution to prepare a carbon fiber-containing paper pulp solution, Comprising the steps of: applying a voltage to the carbon fiber-containing paper pulp solution; flowing the carbon fiber-containing paper pulp solution to which the voltage is applied through a papermaking net to produce a carbon fiber grass; After the silver paste is printed on the edges of two opposite sides in the transverse direction, an electrode made of copper coated with a conductive adhesive is attached on the silver paste Key provides the steps, and, the manufacturing method of the flexible planar heating element to the electrode was coated with carbon fiber-propelled upper and lower surfaces and forming a thermoplastic resin layer.

The thermoplastic resin layer may comprise a thermoplastic polyurethane.

The voltage may be applied in pulse form.

The pulse time of the voltage may be from about 10 ns to about 80 ns.

The voltage may be of the order of magnitude of about 55 V to about 80 V.

The nanoparticle powder may be a mixture of cubic and iron oxide in a weight ratio of about 1: about 0.1 to about 10.

The nanoparticle powder may further comprise at least one selected from the group consisting of anthracite coal, pitch, and silica sand.

The carbon fiber raw material may be cut into a length of about 0.1 mm to about 1 mm and mixed into the paper pulp solution.

The step of applying the voltage may include applying a voltage to the carbon fiber-containing paper pulp solution at the same time as applying the voltage.

In order to achieve the second object, the present invention provides a flexible surface heating element produced by the method of manufacturing the flexible surface heating element, wherein the flexible surface heating element comprises a carbon fiber grass and a thermoplastic polyurethane Wherein the carbon fiber grass sheet includes a pair of electrodes attached to the edges of two sides opposed to each other in the longitudinal direction and a pair of electrodes attached to edges of two sides laterally opposite to each other, Wherein the ratio of the number of contacts between the carbon fibers in the one direction and the number of contacts between the carbon fibers in the other direction is about 100: about 50 to about 60. The flexible surface heating element according to claim 1,

According to the above-described method for producing a flexible surface heating element of the present invention, carbon fiber yarns are prepared by mixing cubic, iron oxide and carbon powder at an appropriate ratio to control electrical properties, The orientation of the carbon fiber yarns is easily induced so that the oriented carbon fiber yarns are homogeneously dispersed and the ratio of the number of contact between the respective carbon fibers in the longitudinal direction and the transverse direction of the paper is different from about 100: It is possible to provide a flexible plane heating element having heat generation characteristics different from each other in the longitudinal direction and the transverse direction by using the carbon fiber grass paper for the planar heating element.

1 shows a method of manufacturing a flexible surface heating element according to an embodiment of the present invention.
FIG. 2 is a view showing a state in which a carbon fiber-containing paper pulp solution to which a voltage is applied in a voltage applying apparatus flows into a papermaking net to form a wet paper in the process of producing carbon fiber grass.
FIG. 3 shows a temperature measurement position in carbon fiber grass in an experimental example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

It is to be understood that the terms or words used in the specification and claims are not to be construed in a conventional or dictionary sense and that the inventor may properly define the concept of a term in order to best describe its invention And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention.

In the specification of the present invention, when a component is referred to as "comprising ", it means that it can include other components as well as other components, .

In the specification of the present invention, "A and / or B" means A or B, or A and B.

Hereinafter, the present invention has been specifically described with reference to the accompanying drawings, but the present invention is not limited thereto.

1 shows a method of manufacturing a flexible surface heating element according to an embodiment of the present invention. Referring to FIG. 1, a method of manufacturing a flexible surface heating element according to an embodiment of the present invention includes mixing and pulverizing cubic and iron oxide to form a nanoparticle powder, mixing the nanoparticle powder with about 1 part by weight to about 10 parts by weight Preparing a carbon fiber yarn having a thickness of about 1 to about 20 mu m by melting and mixing about 50 to about 80 parts by weight of carbon powder, cutting the carbon fiber yarn, mixing the carbon fiber yarn into a paper pulp solution, Comprising the steps of: preparing a fiber-containing paper pulp solution, applying a voltage to the carbon fiber-containing paper pulp solution, flowing the carbon fiber-containing paper pulp solution to which the voltage has been applied, A silver paste is printed on edges of two sides opposite to each other in the longitudinal direction or the transverse direction of the carbon fiber grass, And in the step, and the electrode was coated with carbon fiber-propelled top and bottom surfaces to attach the electrode made of copper and forming a thermoplastic resin layer.

The papermaking pulp solution used in the present invention may be one prepared by adding water to bast fiber such as mackerel, mackerel mackerel, or mackerel. The carbon fiber raw material may be included in an amount of about 10 parts by weight to about 100 parts by weight based on 100 parts by weight of the paper pulp solution. At this time, in order to homogeneously mix the carbon fiber yarn, stirring operation must be accompanied. The carbon fiber is mixed well with the paper pulp solution as compared with the carbon black, so that the carbon fiber can be agglomerated between the carbon fibers, It is desirable to prevent aggregation. When the content of the carbon fiber yarn is less than 10 parts by weight, the power supply performance may be poor. When the content of the carbon fiber yarn is increased, the electric conductivity is increased. However, when the amount is more than 100 parts by weight, The unit price is increased, which is not preferable.

The carbon fiber yarn may be cut to a length of about 0.1 mm to about 10 mm and incorporated into the paper pulp solution.

The length of the carbon fiber yarn is an important factor for imparting carbon fiber orientation, wherein the carbon fiber yarn incorporated into the paper pulp solution has a length of from about 0.1 mm to about 10 mm, or from about 0.1 mm to about 5 mm, or from about 0.1 mm to about 1 mm or from about 0.1 mm to about 0.4 mm, preferably from about 0.1 mm to about 1 mm, and more preferably from about 0.1 mm to about 0.4 mm. When the length of the carbon fiber is longer than 10 mm, it tends to be entangled with the paper pulp, thereby restricting the orientation of the carbon fiber in response to the electrical signal.

The flexible surface heating element may have a ratio of the number of contact between the carbon fibers at the time of energization in one of the longitudinal direction and the transverse direction and the number of contacts between the carbon fibers in the other direction is about 100: have. When carbon fibers existing in the carbon fiber grass are intertwined with each other and current flows in the longitudinal direction or the transverse direction on the carbon fiber grass, electric current flows due to the contact of the carbon fiber, Is displayed. Accordingly, the greater the number of contacts between the carbon fibers during the current flow between the electrodes in the longitudinal direction or the transverse direction, the greater the calorific value. It is preferable that the method of producing a flexible surface heating element according to an embodiment of the present invention exhibits a high calorific value in one of the longitudinal direction and the transverse direction of the grass and exhibits a lower calorific value in the other direction. When the longitudinal and transverse directions are different from each other, the electrode can be selected and easily adjusted to a desired temperature when necessary.

It is preferable that the flexible surface heat generating element exhibits a heat generation characteristic in one direction of the longitudinal direction and a transverse direction of 100, and a heat generation characteristic of about 50 to 60 degrees in the other direction .

The present invention is characterized in that an electric signal of a specific voltage is applied to a paper pulp solution containing carbon fibers in order to change the number of contacts between carbon fibers during conduction in the longitudinal direction or the sulfur direction. At this time, the directionality of the carbon fiber can be controlled by controlling the degree of reactivity to the electricity by varying the components contained in the carbon fiber. Applying a voltage to the carbon fiber-containing papermaking pulp solution is carried out after transferring the homogeneously mixed carbon fiber-containing paper pulp solution to the voltage application device via agitation. At this time, do not accompany the stirring process. In the voltage applying device, the carbon fiber-containing paper pulp solution flows in one direction by the pulse voltage, and the carbon fibers reacted with electricity are arranged in the same direction as the current flows, so that the carbon fibers are aligned in the longitudinal direction And are disposed in contact with each other at a predetermined portion. The pulsed voltage may be repeatedly applied to the carbon fiber-containing paper pulp solution over a number of times to a size of about 55 to 80 V for about 10 to 80 ns, preferably about 65 to 70 ns for about 45 to 55 ns, V to the carbon fiber-containing paper pulp solution repeatedly over several times. The direction of the carbon fiber is determined by the current direction of the voltage applied to the carbon fiber-containing paper pulp solution.

At this time, by further applying vibration to the carbon fiber-containing paper pulp solution at the same time as the voltage is applied, the orientation of the carbon fibers which are physically prevented by the paper pulp can be easily induced. The vibration is preferably a low-frequency vibration within a range that does not cause excessive movement or flow of the carbon fiber-containing paper pulp solution, more specifically, it is preferable to vibrate at a frequency of about 10 Hz to about 100 Hz, Lt; RTI ID = 0.0 > Hz. ≪ / RTI > If the frequency exceeds 100 Hz, the orientation of the carbon fibers may be disturbed by the movement of the paper pulp.

It is very difficult to give directionality to the carbon fibers dispersed in the paper pulp solution because the paper pulp is entangled with the carbon fiber yarn. In the present invention, by repeatedly applying a voltage of a specific size to the carbon fiber-containing paper pulp solution in the form of a pulse, the carbon fiber yarn entangled in the paper pulp can be finely moved and loosened to induce the carbon fiber to have a directionality. When a strong voltage is applied to the carbon fiber-containing paper pulp solution for a short time, the solution vibrates. In addition, low-frequency vibration energy is added to the carbon fiber-containing paper pulp solution to facilitate movement of the carbon fiber yarn.

FIG. 2 shows a state in which the carbon fiber-containing paper pulp solution to which the voltage is applied in the voltage applying apparatus 10 flows into the papermaking net 20 to form the wet paper 100. As a result of the preceding steps of the carbon fiber grass, the wet paper 100 is compressed and dried and developed into grass.

In the present invention, it is important to control the content of cubic and iron oxide in the carbon fiber contained in the carbon fiber grass. Both cubic and ferric iron emit far-infrared rays, and when they are used together, the effect of increasing the amount of far-infrared radiation can be exhibited. The nanoparticle powder may be mixed with cubic and iron oxide in a weight ratio of about 1: about 0.1 to about 10, or about 1: 1. Particularly, when the content of cubic as the non-conductive material is increased, the electrical conductivity of the carbon fiber is lowered and it becomes difficult to realize the directionality of the carbon fiber. If the cubic content is lowered, the synergy effect on the far-infrared radiation can not be obtained. If the amount of iron oxide is excessively increased, the direction of the carbon fiber excessively increases, so that the current flows only in one direction of the longitudinal direction or the lateral direction rather than the bidirectional current flow, and current may not flow in the other direction. The electrical conductivity of the conductive layer may be reduced and it may become difficult to realize the directivity.

In addition, when the carbon fibers contained in the carbon fiber grass paper include cubic and iron oxide mixed in the weight ratio described above, the aggregation of the carbon fibers in the paper pulp solution can be prevented and the dispersibility of the carbon fibers can be improved.

In order to improve the amount of far-infrared radiation, the nanoparticle powder may further include at least one selected from the group consisting of anthracite, pitch, and silica sand.

In the flexible surface heating element of the present invention, when the carbon fibers are uniformly dispersed throughout the carbon fiber grass paper, the carbon fiber grass paper for the surface heating element is uniformly generated in electrical resistance per unit area, It is possible to maximize far-infrared radiation by carbon fiber and cubic nanoparticles. When the flexible surface heating element is energized, the far-infrared rays are radiated, and the carbon fibers and the cubic nano-particles are radiated together to increase the radiation efficiency. The far-infrared rays radiated again become resonant between the carbon atoms constituting the carbon fiber, Furthermore, evenly dispersed carbon fibers become resonant between the connected carbon fibers, thereby maximizing the far-infrared radiation amount.

The nano fiber grass is made of a black material such as black paint such as CuO, Fe ₃ O ₄ (iron oxide), Fe ₃ P (iron phosphate), Fe ₂ MgO ₄ (magnesium oxide iron) Fe (C ₉ H ₇ ) ₂ (bisindenyl iron), or the like may be applied or impregnated to produce black nanoparticle grass.

After the carbon fiber grass is produced, a pair of electrodes are attached to two edges of the carbon fiber grass sheet opposite to each other in the longitudinal direction or the transverse direction. The electrodes are printed on the carbon fiber grass paper in the form of strips using silver paste Then, the silver paste can be processed by attaching a copper-clad tape-coated electrode coated with a conductive adhesive onto the silver paste.

When the electrode attachment is completed, a thermoplastic resin layer is formed on the upper and lower surfaces of the carbon fiber grass to which the electrode is attached. The thermoplastic resin layer may be formed on the carbon fiber grass by a pressing method, but is not limited thereto. The thermoplastic resin plate is prepared in a state that it is not completely cured, and the thermoplastic resin layer is formed between the two thermoplastic resin plates by sandwiching the carbon fiber paper with the electrode attached thereto, and then the thermoplastic resin layer is formed. At this time, it is preferable that the thermoplastic resin plate is previously formed with a hole for attaching a lead wire before press bonding.

A thermoplastic resin plate, a carbon fiber grass, a thermoplastic resin plate, and a release film are arranged in this order on the lower press-bonding plate such as a steel plate, and an upper press plate is placed thereon and pressed. The process may be carried out by applying a pressure of about 30 Kg to about 100 Kg and holding for 1 hour, but may not be limited thereto. The pressing process may be performed at a temperature of less than 90 DEG C, but may not be limited thereto. If the compression temperature is excessively increased, the thermoplastic resin may be melted and the formation of the thermoplastic resin layer may be difficult. The temperature at the time of pressing is preferably about 50 캜 to about 80 캜. When the pressing process is completed, the thermoplastic resin layer is cured by cooling to room temperature.

The thermoplastic resin layer may comprise a thermoplastic polyurethane (TPU). When thermoplastic polyurethane is used, the insulation effect of carbon fiber grass can be obtained, and the elasticity of thermoplastic polyurethane can prevent breakage of the surface heating element, thereby preventing the damage of carbon fiber grass.

In the present invention, an adhesive layer may be further provided between the carbon fiber grass and the thermoplastic resin layer. The adhesive layer may have an adhesive strength of about 4 kgf to about 5 kgf, and the adhesive layer may be made of ethylene vinyl acetate resin or polyurethane resin. In addition to improving the adhesive strength, the adhesive layer can also protect the carbon fiber grass from external impact or vibration and store the generated heat.

The hardness of the thermoplastic resin layer is preferably about 83A to about 87A. When the hardness is less than 83A, there is a problem of bending. When the hardness is more than 87A, the flexibility of the product is low.

When a lead is connected to one end of the electrode by soldering or the like, a flexible surface heating element is completed.

Further, the present invention provides a flexible surface heating element produced by the above method for producing a flexible surface heating element, wherein the flexible surface heating element comprises a carbon fiber grass and a thermoplastic polyurethane layer applied on the top and bottom surfaces of the carbon fiber grass, The carbon fiber grass sheet includes a pair of electrodes attached to the edges of two sides opposed to each other in the longitudinal direction and a pair of electrodes attached to the edges of the two sides that are laterally opposed to each other. In the longitudinal direction and the transverse direction, Wherein the ratio of the number of contacts between the carbon fibers to the number of contacts between the carbon fibers in the other direction is about 100: about 50 to about 60.

The carbon fiber raw material contained in the carbon fiber grass may include about 1 to about 10 parts by weight of the nanoparticle powder per about 50 to about 80 parts by weight of the carbon powder. When the nanoparticle powder is contained in an amount of less than 1 part by weight, the synergistic effect of the carbon fiber raw material in the far-infrared radiation can not be expected and the carbon fiber dispersibility may not be excellent. When the amount of the nanoparticle powder exceeds 10 parts by weight, If the carbon fiber is included in an amount of 50 to 80 parts by weight, the content of cubic bitumen becomes excessively high, leading to a decrease in the conductivity of the carbon fiber.

Contact between the carbon fibers enables energization, and the higher the number of contacts, the higher the exothermic temperature. When a pair of electrodes are arranged in the longitudinal direction or the transverse direction on the carbon fiber grass paper and electrons emitted from the cathode are transmitted to the anode through the carbon fibers connected to each other when a voltage is applied between the pair of electrodes, A resistance is generated and a heat is generated.

The carbon fiber grass sheet may have heat generation characteristics different from each other in the longitudinal direction and the transverse direction. The greater the number of contacts between the carbon fibers, the higher the electrical resistance and the higher the heat generation. The flexible surface heating element according to an embodiment of the present invention can generate heat at a high temperature in either the longitudinal or transverse direction, for example, from about 95 ° C to about 110 ° C, and in other directions, To about 60 < 0 > C, but the present invention is not limited thereto.

It is preferable that the temperature difference between the longitudinal direction and the transverse direction of the flexible surface heating element is about 40 캜 or more, for example, about 40 캜 to about 70 캜 or about 45 캜 to about 60 캜.

Since the flexible surface heating element includes the thermoplastic polyurethane formed on the surface of the carbon fiber cloth, it is possible to obtain the insulating effect of the carbon fiber grass. The elasticity of the thermoplastic polyurethane prevents the surface heating element from being bent, .

Preferably, the flexible surface heating element has a final thickness of less than 0.5 mm, but the present invention is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are given for the purpose of helping understanding of the present invention, but the present invention is not limited to the following Examples.

< Example  And Comparative example  Manufacturing>

Example  One

One. Of carbon fiber yarn  Produce

10 parts by weight of cubic zirconia, 10 parts by weight of iron oxide (Fe ₃ O ₄ ), 1 part by weight of anthracite coal, 1 part by weight of pitch and 1 part by weight of silica sand were sequentially mixed and pulverized by a pulverizing machine, Or less to obtain a nanoparticle powder.

The mixture of coke and pitch was melted by heating at 2000 ° C in an arc furnace, cooled to room temperature, and pulverized to a particle diameter of 1 μm or less by a microfibrillator to obtain a carbon powder.

The carbon powder was heated to 800 DEG C to remove impurities and cooled to room temperature. 60 parts by weight of the carbon powder from which impurities were removed was added to a mixed solution of sulfuric acid and nitric acid to dissolve the mixture. 10 parts by weight of the nanoparticle powder was mixed with the mixed solution and sprayed with a high-pressure jet nozzle to prepare a 10- Respectively. The produced carbon fiber yarn is passed through a washing machine, wound around a yarn bobbin by a winder, and cut into a desired length.

2. Carbon fiber grassland  Produce

50 parts by weight of the carbon fiber yarn cut to 0.4 mm length was mixed into 100 parts by weight of the ultra fine powdered paper pulp solution and homogeneously mixed.

The pulsed voltage applied to the paper pulp solution containing carbon fibers at 55 V for 50 ns was repeated several times to orient the carbon fibers in a direction parallel to the direction of the current. At this time, 40 Hz low frequency vibration was applied while the pulse voltage was applied.

The paper pulp solution containing the carbon fiber having the directionality was poured onto the papermaking net to form a wet paper. The wet paper was dewatered by a press roll, dried and cut to a size of 20 cm in width / length to obtain carbon fiber grass .

3. flexible Of the surface heating element  Produce

A pair of electrodes in the longitudinal direction and a pair of electrodes in the transverse direction were respectively disposed to form the heating sheet by printing the electrodes using silver paste on each of the carbon fiber grass pads. The TPM film (PC-8300P, P & C Tech) was placed on the upper and lower surfaces of the heat-generating sheet in a thickness of 50 mu m with a thickness of 150 mu m, and a release film was placed on the final upper and lower surfaces. To form a thermoplastic polyurethane layer. After the pressing was completed, all the release films were removed. Then, a conductive wire was connected to each electrode, and a current was allowed to flow when energizing the longitudinal or transverse electrode to form a flexible surface heating element.

Example  2

Carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that 10 parts by weight of cubic zirconia and 1 part by weight of iron oxide were used. Then, the carbon fiber paper of Example 1 and the flexible surface heating element A flexible surface heating element was prepared.

Example  3

Carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that 1 part by weight of cubic zirconia and 10 parts by weight of iron oxide were used. Then, the production process of the carbon fiber grass of Example 1 and the production of the flexible surface heating element A flexible surface heating element was prepared.

Example  4

A carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1 except that the length of the carbon fiber yarn was changed to 1 mm. Then, the production process of the carbon fiber grass of Example 1 and the production of the flexible surface heating element A flexible surface heating element was prepared.

Example  5

A carbon fiber yarn was produced in the same manner as in the manufacturing process of the carbon fiber yarn of Example 1 except that the length of the carbon fiber yarn was changed to 5 mm. Then, the manufacturing process of the carbon fiber grass of Example 1 and the production of the flexible surface heating element A flexible surface heating element was prepared.

Example  6

A flexible surface heating element was prepared in the same manner as in the production process of the carbon fiber grass of Example 1 and the manufacturing process of the flexible surface heating element without applying the low frequency vibration when the pulse voltage was applied.

Example  7

The carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1 except that the pulse voltage was applied at 70 V, and the production process of the carbon fiber grass of Example 1 and the manufacturing process of the flexible surface heating element A flexible surface heating element was produced in the same manner.

Example  8

A carbon fiber yarn was produced in the same manner as in the manufacturing process of the carbon fiber yarn of Example 1 except that a vibration of 45 Hz low frequency was applied together while the pulse voltage was applied and then the process of manufacturing the carbon fiber grass of Example 1 and the flexible A flexible surface heating element was prepared in the same manner as in the production of the surface heating element.

Example  9

A carbon fiber yarn was produced in the same manner as in the manufacturing process of the carbon fiber yarn of Example 1 except that a vibration of 5 Hz low frequency was applied together while the pulse voltage was applied and then the manufacturing process of the carbon fiber grass of Example 1 and the flexible A flexible surface heating element was prepared in the same manner as in the production of the surface heating element.

Example  10

A carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that the vibration of 110 Hz frequency was applied while the pulse voltage was applied. Then, the carbon fiber yarn of Example 1 and the flexible A flexible surface heating element was prepared in the same manner as in the production of the surface heating element.

Comparative Example  One

A carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that a nanoparticle powder containing only cubic was manufactured to produce a carbon fiber yarn. Then, the carbon fiber yarn was produced in the same manner as in Example 1 And a flexible surface heating element were manufactured in the same manner as in the production of the flexible surface heating element.

Comparative Example  2

The carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1 except that the carbon fiber yarn was produced using only the carbon powder without using the nano-particle powder, And a planar heating element was manufactured in the same manner as the manufacturing process and the manufacturing process of the flexible flat heating element.

Comparative Example  3

A carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1 except that 15 parts by weight of the nanoparticle powder was mixed with 60 parts by weight of the carbon powder. A planar heating element was manufactured in the same manner as the planar heating element.

Comparative Example  4

A carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that the length of the carbon fiber yarn was changed to 15 mm. Then, the carbon fiber grass produced in Example 1 and the flexible surface heating element Plane heat generating body was produced in the same manner as in the above process.

Comparative Example  5

The carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that the pulse voltage was applied at 40 V. Then, the manufacturing process of the carbon fiber grass of Example 1 and the manufacturing process of the flexible surface heating element A planar heating element was prepared in the same manner.

Comparative Example  6

The carbon fiber yarn was produced in the same manner as in the production of the carbon fiber yarn of Example 1, except that the pulse voltage was applied at 100 V. Then, the production process of the carbon fiber grass of Example 1, the production process of the flexible surface heating element A planar heating element was prepared in the same manner.

Experimental Example  One: Energization  Character rating

The flexible surface heating elements prepared in Examples 1 to 10 and Comparative Examples 1 to 5 were placed in a closed space having a room temperature of 20 占 폚 and energy density of 700 W / m &lt; ² &gt; for 2 minutes as longitudinal or transverse electrodes of the flexible surface heating elements And then the surface temperature on the flexible surface heating element was measured. The temperature was measured at five different positions (positions 1 to 5 in FIG. 2) for each flexible surface heating element, and the temperature was measured and the average value was shown in Table 1 below.

Longitudinal direction Lateral direction Difference Example  One 105.7 ° C 55.2 DEG C 50.5 DEG C Example  2 102.9 ° C 54.8 ° C 48.1 DEG C Example  3 109.3 DEG C 50.1 DEG C 59.2 DEG C Example  4 101.2 DEG C 53 ℃ 48.2 DEG C Example  5 100.7 DEG C 52.4 DEG C 48.3 DEG C Example  6 99.3 DEG C 54.2 DEG C 45.1 DEG C Example  7 106.2 DEG C 46.1 DEG C 60.1 DEG C Example  8 105.9 ° C 46.2 DEG C 59.7 DEG C Example  9 100.7 DEG C 54.3 DEG C 46.4 DEG C Example  10 98.2 ° C 54.7 ° C 43.5 DEG C Comparative Example  One 93.0 DEG C 91.7 ℃ 1.3 DEG C Comparative Example  2 ^* 88.3 DEG C
(Total after 5 minutes: 95.5 ° C) 49.6 ° C
(Total after 5 minutes: 63.1 DEG C) 39 ° C
(32.4 DEG C) Comparative Example  3 91.5 ° C 80.2 DEG C 11.3 DEG C Comparative Example  4 90 ° C 68.1 DEG C 21.9 ° C Comparative Example  5 89.4 DEG C 55.1 DEG C 34.3 DEG C

^* Comparative Example  2 minutes for 2 minutes Energize  After measuring the primary temperature, the energy density 700 W / m ² And the second temperature Respectively. Secondary  The measurement temperature is indicated in parentheses.

As a result of the energization test, the flexible surface heating elements of Examples 1 to 10 showed a temperature difference of 1 DEG C or less and a similar value in all five locations of the surface heating elements when current was supplied to the longitudinal or transverse electrodes. When the contents of cubic and iron oxide were adjusted as in Examples 1 to 3, when the length of the carbon fiber yarn was adjusted as in Examples 4 and 5, when vibration was not applied together with voltage application as in Example 6, When the magnitude of the pulse voltage was adjusted as in Example 7, even when the vibration frequency was adjusted as in Examples 8 to 10, the orientation of the carbon fibers progressed smoothly, and the difference in heat generation characteristics in longitudinal / I can implement it. In the case of the examples, a uniform temperature was confirmed as a whole. From these results, it can be seen that the carbon fiber yarns of Examples 1 to 10 are well dispersed in the grass. On the other hand, in the comparative examples, it was confirmed that the carbon fiber yarn was not well dispersed, and in Comparative Example 2, the temperature difference was more than 5 ° C for each position.

In Comparative Example 1 in which the carbon fiber yarn contained cubic zirconium, the temperature difference during energization in the longitudinal direction and in the transverse direction was not large, which is considered to be because the orientation of the carbon fiber in response to the pulse voltage was not smooth. The planar heating element of Comparative Example 1 contained cubic as the nonconductor, so that the electrical conductivity of the carbon fiber was lowered by the cubic nano-particle powder, and the carbon fiber dispersed in the paper pulp solution did not respond properly to the applied pulse voltage. From these results, Examples 1 to 10 also revealed cubic nanoparticles but differed in heat generation characteristics in the longitudinal / transverse directions from 43.5 DEG C to 60.1 DEG C, as the iron oxide having electric conductivity was used together with cubic, It is understood that the carbon fibers dispersed in the paper pulp solution are well-oriented in response to the pulse voltage. Thus, it can be seen that the coexistence of cubic and iron oxide in carbon fiber yarn is one of the main factors in determining the orientation of carbon fiber.

The temperature in the longitudinal direction and the transverse direction of Comparative Example 1 is lower than that of Examples 1 to 10, which is a result that the far infrared ray radiation amount is smaller than those of the Examples. Comparative Example 1 uses nanoparticle powder containing only cubic, which does not contain iron oxide. In Examples 1 to 10, the far infrared ray radiation amount increases according to the coexistence of cubic and iron oxide, and ultimately, the heat generation efficiency during energization is improved.

It was confirmed that the heat generation efficiency in Comparative Example 2 was lower than that in Examples 1 to 10 because the time for reaching the final temperature was long. In addition, the surface heating element of Comparative Example 2 had a large temperature difference at each part, and carbon fiber yarn composed of only carbon powder without using nanoparticle powder was not dispersed well in paper pulp solution. In contrast, in Examples 1 to 10, carbon fiber yarns were formed by controlling the ratio of cubic and iron oxides. As a result, it was found that the dispersibility of the carbon fiber yarn in the paper pulp solution was improved. In Examples 1 to 10, since the dispersibility of the carbon fiber yarn is good, the far infrared ray resonance phenomenon between the carbon fibers is increased, and the far infrared ray radiation amount is maximized, and the heat generation efficiency is improved.

In Comparative Example 3, the content of the nanoparticle powder in the carbon fiber yarn was high. In this case, it was confirmed that the heat generation efficiency was not good similarly to Comparative Example 1. This is a result of decreasing the electrical conductivity of the carbon fiber due to the increase of the cubic content with the increase of the nanoparticle powder content. In this case, although the heating characteristics in the longitudinal direction and the lateral direction were somewhat different, it was difficult to see that the difference was small and had distinctly different heating characteristics.

In Comparative Example 4, the length of the carbon fiber yarn is as long as 15 mm, and when the length of the carbon fiber yarn is long, it is expected that the carbon fiber is severely intertwined with the paper pulp so that the carbon fiber is oriented in response to the pulse voltage. In Comparative Example 4, it was confirmed that there was a difference in heat generation characteristics in the longitudinal direction and in the lateral direction, but it is difficult to see that the difference is small and thus has distinctly different heat generation characteristics.

In Comparative Example 5, it was confirmed that the magnitude of the applied pulse voltage was 40 V, the voltage was insufficient in size, and the orientation of the carbon fiber was not remarkably improved as compared with Examples 1 to 10.

Experimental Example  2: Far-infrared radiation measurement

Far infrared rays emitted from each of the flexible surface heating elements manufactured in Examples 1 to 6 and Comparative Examples 1 to 4 were measured. The far-infrared ray measurement was carried out according to the test method KFIA-FI-1005 using a FIR spectrometer of Korea Far Infrared Spectroscopy and the emissivity and radiant energy were measured at a wavelength of 5 to 20 μm at 100 ° C.

Emissivity % ) Radiant energy  (W / m ² 占 퐉) Example  One 93.5 7.64 x 10 ² Example  2 92.7 7.50 x 10 ² Example  3 93.1 7.48 x 10 ² Example  4 92.5 7.21 x 10 ² Example  5 91.9 7.05 x 10 ² Example  6 89.6 6.91 x 10 ² Comparative Example  One 87.8 2.37 x 10 ² Comparative Example  2 85.2 1.40 x 10 ² Comparative Example  3 86.9 2.03 x 10 ² Comparative Example  4 85 3.11 x 10 ²

Referring to Table 2, Examples 1 to 6 were confirmed to emit far infrared rays in the range of 5 to 20 占 퐉, and the emissivity was as high as about 90% or more. On the contrary, the comparative examples showed low emissivity and radiant energy.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. You will understand. It is therefore to be understood that the embodiments described above are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: voltage applying device
20: Grid Network
30: longitudinal electrode
40: transverse electrode
100: Wetlands
200: Planar heating element

Claims (10)

Mixing and pulverizing cubic and iron oxide to form a nanoparticle powder;
1 to 10 parts by weight of the nanoparticle powder and 50 to 80 parts by weight of carbon powder are melted and mixed to prepare a carbon fiber yarn having a thickness of 1 to 20 μm;
Cutting the carbon fiber yarn and mixing it into a paper pulp solution to produce a carbon fiber-containing paper pulp solution;
Applying a voltage to the carbon fiber-containing paper pulp solution;
The method comprising the steps of: flowing a carbon fiber-containing paper pulp solution to which a voltage is applied to a papermaking net to thereby produce carbon fiber grass;
Printing a silver paste on edges of two opposite sides of the carbon fiber grass paper in the longitudinal direction or the transverse direction and then attaching the copper electrode coated with the conductive adhesive onto the silver paste; And
A step of forming a thermoplastic resin layer on the surface of the carbon fiber cloth having the electrodes attached thereto
And heating the flexible surface heating element.
The method according to claim 1,
Wherein the thermoplastic resin layer comprises a thermoplastic polyurethane.
The method according to claim 1,
Wherein the voltage is applied in a pulse form.
The method of claim 3,
Wherein the pulse time of the voltage is 10 to 80 ns.
The method according to claim 1,
Wherein the voltage is in the range of 55 to 80 V. &lt; RTI ID = 0.0 &gt; 18. &lt; / RTI &gt;
The method according to claim 1,
Wherein the nanoparticle powder is a mixture of cubic and iron oxide in a weight ratio of 1: 0.1 to 10.
The method according to claim 1,
Wherein the nanoparticle powder further comprises at least one selected from the group consisting of anthracite coal, pitch, and silica sand.
The method according to claim 1,
Wherein the carbon fiber raw material is cut to a length of 0.1 to 1 mm and is mixed into the paper pulp solution.
The method according to claim 1,
Wherein the step of applying the voltage comprises applying a voltage to the carbon fiber-containing paper pulp solution at the same time as applying the voltage, thereby producing a flexible surface heating element.
A flexible surface heating element produced by the method for producing a flexible surface heating element according to claim 1,
Wherein the flexible surface heating element comprises a carbon fiber grass and a thermoplastic polyurethane layer applied on the upper and lower surfaces of the carbon fiber grass,
The carbon fiber grass sheet includes a pair of electrodes attached to edges of two sides opposed to each other in a longitudinal direction and a pair of electrodes attached to edges of two sides that are laterally opposed to each other. In the longitudinal direction and the transverse direction, Wherein the ratio of the number of contacts between the carbon fibers in the other direction and the number of contacts between the carbon fibers in the other direction is 100: 50 to 60. &lt; Desc / Clms Page number 39 &gt;

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