JP5845038B2 - Planar heating element - Google Patents

Description

  The present invention relates to a planar heating element including an electrode portion having excellent bending durability.

  Conventionally, planar heating elements have been used in indoor heating devices such as floor heating and hot carpets, and anti-condensation devices or anti-fogging devices. In addition, a flexible cloth-like sheet heating element is used for a cold clothing or a vehicle seat, and the sheet heating element has been put to practical use in a wide range of fields.

  The planar heating element is manufactured by arranging linear materials (nichrome wire, carbon fiber, etc.) that generate heat when energized in a planar shape. For example, in Patent Document 1, the ground structure is a woven or patterned woven structure having a wide gap, the electrode part is a plain woven structure having a high woven density, and thermoplastics on both sides are formed through the gaps of the ground structure other than the electrode part. A heating element fabric obtained by thermocompression bonding a resin film is described. Further, in Patent Document 2, the heat generation part is a pattern weave using a heat-resistant / non-conductive yarn and a carbon fiber inserted at a predetermined interval, and the electrode part intersects the carbon fiber on both sides of the heat generation part. A plain weave woven with conductive wires, and a plain weave cushion part using heat-resistant and non-conductive yarn is woven between the heat generating part and the electrode part, and a plastic film is bonded and laminated to the resulting heat generating woven cloth A heating element is described. Moreover, in patent document 3, in the planar heating element comprised by the heat-generation part formed with the knitted fabric containing a conductive fiber, and the electrode part for supplying with electricity to this heat-generation part, a conductive fiber is made into organic fiber. And a planar heating element composed of carbon nanotubes covering the surface of the organic fiber.

JP 9-326291 A JP-A-11-283373 JP 2010-192218 A

  As described in Patent Documents 1 and 2, when carbon fibers that generate heat when energized are arranged at intervals, a non-uniform heat generation distribution is generated over the entire surface. In addition, it is necessary to perform thermocompression bonding with a plastic film so that the heating fibers do not shift, and there are disadvantages that the manufacturing process becomes complicated and the manufacturing cost increases.

  Patent Document 3 describes that an electrode part is formed by sticking a conductive tape to a heat generating part made of a woven fabric with a conductive adhesive or introducing a metal fiber as a warp. Or when a metal fiber is used as an electrode part, there exists a subject that it will be easy to disconnect, if it bends and deforms.

  Accordingly, an object of the present invention is to provide a planar heating element having an electrode portion that has durability against bending deformation and has stable electrical characteristics.

The planar heating element according to the present invention includes a heating portion in which a ground yarn made of an insulating fiber material and a heating yarn made of a conductive fiber material coated with a conductive material on the surface are arranged in the weft direction and woven, A plurality of conductive yarns formed in a predetermined width adjacent to the heat generating portion and arranged in place of the ground yarn and an electrode portion woven with the heat generating yarn, wherein the conductive yarn is made of an insulating fiber material This is a processed yarn having a resistance of 1 Ω / m to 50 Ω / m obtained by double- covering a metal fine wire having a diameter of 10 μm to 100 μm on the core yarn. Further, in the conductive yarn, a yarn made of the same insulating fiber material as the ground yarn is used for the core yarn. Further, the conductive yarn is covered with metal fibers at a winding number of 3,000 turns / m to 8,000 turns / m. Furthermore, the heat generating yarn uses a conductive fiber material in which the surface of the same insulating fiber material as that of the ground yarn is coated with carbon nanotubes.

  Since the planar heating element according to the present invention has the above-described configuration, the planar heating element can include an electrode portion having durability against bending deformation and having stable electrical characteristics.

It is a top view regarding the embodiment concerning the present invention. It is a top view regarding a conductive yarn. 3 is a graph showing measurement results regarding Example 1. 6 is a graph showing measurement results regarding Example 2.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a plan view relating to an embodiment of the present invention. As shown in FIG. 1A, the planar heating element 1 is formed in a sheet shape, and electrode portions 3 are formed adjacent to both sides of a heating portion 2 formed in a rectangular shape. FIG. 1B is a partially enlarged plan view relating to the heat generating portion 2. The heat generating portion 2 is formed of a woven structure in which the warp 20 and the weft 21 are woven in a plain weave. The warp yarn 20 is a ground yarn made of an insulating fiber material, and the weft yarn 21 is a heating yarn made of a conductive fiber material having a surface coated with a conductive material.

  The yarn used for the ground yarn is preferably an electrically insulating one having a relative dielectric constant of 4 or less. Specifically, polyester fibers such as PET (polyethylene terephthalate), PTT (polytrimethylene terephthalate) or PBT (polybutylene terephthalate), nylon (polyamide fiber), aramid (aromatic polyamide fiber), polypropylene or polyethylene, etc. Examples thereof include polyolefin fibers, synthetic fibers such as acrylic, chemical fibers such as rayon and acetate, and natural fibers such as cotton, hemp, wool, and silk. Moreover, you may use the composite fiber which mixed multiple types of these fibers. The fineness of the yarn is preferably 22 dtex to 330 dtex.

  As the yarn used for the heat generating yarn, a yarn made of a conductive fiber material in which a conductive layer such as a metal coating layer or a carbon coating layer is formed on the surface of the insulating fiber material used for the ground yarn may be used. If there is, it will not be specifically limited. Examples of the conductive fiber material on which the metal coating layer is formed include those formed on the surface of the insulating fiber material by a known method such as electroless plating. Examples of the conductive fiber material on which the carbon coating layer is formed include those in which carbon nanotubes are fixed to the surface of the insulating fiber material with a binder. As the exothermic yarn, a combination of a plurality of yarns can be used according to the application.

  By using a yarn made of the same insulating fiber material as the ground yarn as the heating yarn, the warp yarn 20 as the ground yarn and the weft yarn 21 as the heating yarn have substantially the same stretch characteristics, and even when woven into a woven fabric The warp yarn 20 and the weft yarn 21 are deformed in the same way with respect to expansion and contraction deformation and bending deformation in the warp direction and the weft direction, so that the durability can be improved without almost shifting the woven structure. In addition, by using yarns made of the same insulating fiber material with the same fineness as the ground yarn, the two yarns can have the same stretch characteristics and bending characteristics, and further improve durability. It becomes possible to improve.

  FIG. 1C is a partially enlarged plan view of the electrode unit 3. The electrode unit 3 includes a plurality of conductive yarns 30 arranged in the warp direction instead of the warp yarns 20, and is formed of a woven structure in which wefts 21 and heat conductive yarns 30 that are heat generating yarns are woven in a plain weave.

  The conductive yarn 30 is obtained by covering a core fiber made of an insulating fiber material with a long fiber metal fiber. Examples of the core yarn include fiber materials used for ground yarn. Examples of the metal fiber include copper fiber, nickel fiber, tin bronze fiber, iron fiber, silver fiber, and stainless steel fiber, and nickel fiber that is less susceptible to deterioration such as rust when used over a long period of time is preferable. It is desirable that the metal fiber has strength against breakage without impairing the flexibility of the conductive yarn 30. In the case of a metal thin wire, a metal fiber having a diameter of 10 μm to 100 μm is preferable. If the diameter is smaller than 10 μm, there is a risk of disconnection during the covering process. If the diameter is larger than 100 μm, the entire diameter of the conductive yarn 30 becomes thicker, resulting in a characteristic different from the deformation characteristics of the heat generating portion, and the surface heat generation. It will adversely affect the deformation characteristics of the body.

  As the covering process, there are a single covering process and a double covering process. FIG. 2 shows a conductive thread that has been subjected to a double covering process in which metal fibers 32 are wrapped around the core thread 31 in a double manner. Yes. In this way, by winding a plurality of metal fibers so as to cross each other, the metal fibers come into contact with each other and have durability against disconnection of the metal fibers. The number of metal fibers to be wound may be two or more.

  The conductive yarn 30 desirably has an electrically low resistance, and the electrical resistance is preferably set to 1 Ω / m to 50 Ω / m. When the electric resistance exceeds 50 Ω / m, the power consumption of the electrode part 3 increases and heat is easily generated, and the heat generating part 2 is prevented from generating heat uniformly.

  The conductive yarn 30 has substantially the same characteristics as the core yarn by setting the number of windings of the metal fiber to be covered to 3,000 times / m to 8,000 times / m. Therefore, by using the yarn made of the insulating fiber material used for the weft 21 as the core yarn, the weft 21 and the conductive yarn 30 have the same flexibility and stretchability, and the electrode portion 3 is bent or stretched. Even in this case, it is possible to follow the deformation of the electrode portion 3 without the conductive yarn 30 being disconnected or displaced. Therefore, the weft yarn 21 and the conductive yarn 30 which are heat generating yarns are always in a stable contact state, and an electrode portion having stable electrical characteristics can be formed. In addition, by using a conductive yarn made of the same insulating fiber material with the same fineness as that of the heat generating yarn, the two yarns can have the same stretch characteristics and bending characteristics, and further electrical characteristics Can be stabilized.

  Further, by using the warp yarn 20, the weft yarn 21 and the conductive yarn 30 made of the same insulating fiber material, the entire sheet heating element has the same expansion and contraction characteristics and bending characteristics, and the entire sheet heating element is deformed. In contrast, it is provided with durability that causes almost no deviation of the yarn.

  The amount of heat generated by the heat generating portion 2 is determined by the current density supplied to the heat generating portion 2 when the electric resistance per unit length of the weft 21 as a heat generating yarn is constant. 21 (width in the direction perpendicular to the yarn length direction)) and the number of wefts 21 (hereinafter referred to as “density number”). Therefore, the calorific value can be easily set by adjusting the density of the wefts 21 in accordance with the use of the planar heating element. When adjusting the number of density of the wefts 21, it is possible to reduce the number of density by arranging yarns made of the same insulating fiber material as the ground yarn between the wefts 21, and by adjusting the number of density in this way, The calorific value can be adjusted without substantially changing the expansion and contraction characteristics and the bending characteristics of the planar heating element.

  When the heat generation design of the planar heating element is performed based on the density of the weft yarns 21 that are the heat generation yarns, it is assumed that all the heat generation yarns are evenly supplied with current from the electrode unit 3. As described above, in the electrode portion 3, the weft 21 and the conductive yarn 30 are in a stable contact state, and the plurality of conductive yarns 30 are in contact with one weft 21, so that each weft 21 and the electrode portion are in contact with each other. It is possible to make the electrical connection state between the terminals 3 and 3 almost the same. Therefore, almost uniform current flows through each weft 21 so that heat generation can be designed according to the number of heat generation yarns, and a highly practical planar heating element in which the entire heat generating portion generates heat uniformly can be realized.

  When weaving the above-mentioned planar heating element, it can be woven by plain weaving using a known loom. By arranging a plurality of conductive yarns on both sides of a predetermined number of ground yarns as warp yarns and weaving heat generating yarns as weft yarns, the heat generating portion and the electrode portion can be woven simultaneously. Then, a woven fabric in which a heat generating portion is formed between electrode portions formed by a plurality of conductive yarns arranged at a predetermined interval is woven. And the sheet | seat heat generating body which formed the electrode part in the both sides of the heat generating part can be obtained by cut | disconnecting by the length of the longitudinal direction according to the size of the sheet | seat heating element.

  When the size of the sheet heating element is large, the conductive yarns are arranged in the middle part in addition to the both sides of the ground yarn arranged in the warp direction so that the electrode part is also formed in the middle part of the sheet heating element. It can also be configured. Therefore, it becomes possible to easily manufacture planar heating elements corresponding to various uses and sizes. It is also possible to press the electrode portion against the woven planar heating element or to apply a conductive paste to further enhance the conduction state between the heating yarn and the conductive yarn.

  In the example described above, the heat generating yarn is used as the weft, but the heat generating yarn is used as the warp to make the weft into a ground yarn and a conductive yarn. In addition to plain weave, a planar heating element can be woven by satin weave or oblique weave, and a woven structure obtained by changing these three major weave structures can also be used.

<Example 1>
A yarn (84 dtex / 36f) made of polyester multifilament was used as the ground yarn. In addition, as a heating yarn, a yarn in which carbon nanotubes were fixed to the surface of a polyester multifilament (manufactured by Kuraray Living Co., Ltd .; product name CNTEC, 84 dtex / 48f, electric resistance value 10 ³ Ω / cm) was used.

  As the conductive yarn, a processed yarn subjected to a covering process in which two copper fine wires having a diameter of 50 μm were wound around a yarn (167 dtex / 48 f) made of polyester multifilament was used. The electric resistance value per unit length was 5 Ω / m.

  A sample of 2 cm width woven by plain weaving using 16 conductive yarns as warp yarns and exothermic yarns as weft yarns was prepared and subjected to a fatigue test using a Scott-type paddle tester. In the fatigue test, one end of the sample was fixed, and the other end was reciprocated with a width of 4 cm to repeatedly bend the sample 90 degrees. One reciprocation was taken as one time, and the electric resistance of the conductive yarn was measured every 1,000 times to perform a total of 25,000 bending operations. As a result of measuring the electric resistance, there was almost no change in the resistance value. In addition, when the conductive yarn was observed with a microscope every 1,000 times, a broken portion of the copper fine wire was seen at 4,000 times or more, but this did not affect the electrical resistance of the conductive yarn. It has been confirmed that it has sufficient durability for use as an electrode part.

  A ground yarn and a conductive yarn were arranged as warp yarns, and a heat generating yarn was arranged as a weft yarn, and weaved by plain weaving at a warp density of 200 / inch and a weft density of 87 / inch. The woven fabric has a heat generating portion in which ground yarns are arranged in the warp direction and electrode portions in which 16 conductive yarns are arranged in the warp direction on both sides of the heat generating portion. The width in the direction was 32 cm, and the width in the weft direction of the electrode portion was 0.6 cm.

  The woven fabric was cut at a length of 50 cm in the warp direction to prepare a planar heating element in which a pair of electrode parts were formed on both sides of the heating part. In the sheet heating element, the heating part formed between the electrode parts was formed in a rectangular shape with a length of 50 cm in the warp direction and a width of 32 cm in the weft direction, and the density of the heating yarn was 87 / inch.

  A terminal component was fixed to the end portion of the electrode portion of the produced planar heating element with a conductive adhesive, and power was supplied to the terminal component to cause the planar heating element to generate heat. When the heat generation state was observed by thermography, it was confirmed that the surface temperature rose uniformly and the heat was generated almost uniformly throughout.

  In addition, the voltage applied to the planar heating element was changed, and the current, electrical resistance, power consumption, and surface temperature were measured. The outside temperature during the measurement was about 28 ° C. The measurement results are shown in FIG. From this measurement result, it can be seen that as the voltage rises, the current rises so as to be approximately proportional, and the electrical resistance value hardly fluctuates depending on the voltage. Therefore, the surface temperature of the sheet heating element can be set accurately.

<Example 2>
The same ground yarn, heat generating yarn and conductive yarn as in Example 1 were used, the ground yarn and conductive yarn were arranged as the warp, and the heat generating yarn was arranged as the weft, and the warp density was 200 / inch and the weft density was 124 / inch. Weaved with satin weave. The woven fabric has a heat generating portion in which ground yarns are arranged in the warp direction and electrode portions in which 16 conductive yarns are arranged in the warp direction on both sides of the heat generating portion. The width in the direction was 32 cm, and the width in the weft direction of the electrode portion was 0.6 cm.

  The woven fabric was cut at a length of 50 cm in the longitudinal direction to prepare a planar heating element in which a pair of electrode portions were formed on both sides of the heating portion. In the sheet heating element, the heating part formed between the electrode parts was formed in a rectangular shape having a length of 50 cm in the warp direction and a width of 32 cm in the weft direction, and the density of the heating yarns was 124 / inch.

  Similarly to Example 1, the woven fabric was cut to create a planar heating element, the terminal component was fixed to the electrode portion, and power was supplied to the terminal component to cause the planar heating element to generate heat. When the heat generation state was observed by thermography, the surface temperature was increased uniformly, and it was confirmed that heat was generated almost uniformly over the entire surface as in Example 1.

  Measurement was performed in the same manner as in Example 1 by changing the voltage applied to the planar heating element. The measurement results are shown in FIG. From this measurement result, it can be seen that, as in Example 1, as the voltage increases, the current increases so as to be approximately proportional, and the electrical resistance value hardly varies depending on the voltage.

In a state in which a voltage of 100 V is applied, in Example 1, the current value is 0.65 A, and the ratio of the density of the heating yarn of the heating portion to 87 yarns / inch is as follows:
0.65 / 87 = 0.0075
It becomes. Further, in Example 2, the current value is 0.91 A, and the ratio of the density of the heating yarn of the heating portion to 124 / inch is:
0.91 / 124 = 0.0073
It becomes. Therefore, the current value increases almost in proportion to the number of densities, and the current density can be set based on the number of density of the heating yarns of the planar heating element. Thus, by using the sheet heating element according to the present invention, it becomes possible to perform accurate heat generation design.

  Since the sheet heating element according to the present invention can accurately set the amount of heat generation, it can correspond to a wide range of applications using the heating element. For example, since it has flexibility and bending durability, it can be used for a seat for a vehicle. Moreover, since it is thin and has flexibility, it can be used for indoor heating devices for buildings (condensation prevention device, anti-fogging device, floor heating, wall heating, hot carpet, etc.). In addition, since it is lightweight and flexible and can be easily processed, it can also be used for clothing for winter and personal belongings (jackets, vests, rugs, bedding, shoes, warmers, etc.). Further, it can be used for outdoor facilities such as roofs and roads (snow melting devices, anti-freezing devices, etc.) and agricultural heating facilities (such as gardening laying mats).

DESCRIPTION OF SYMBOLS 1 ... Planar heating element, 2 ... Heat generating part, 3 ... Electrode part, 20 ... Warp, 21 ... Weft, 30 ... Conductive yarn, 31 ... Core yarn, 32 ... Metal fibers

Claims (4)

Formed with a predetermined width adjacent to the heat generating portion, and a heat generating portion formed by weaving ground yarn made of insulating fiber material and heat generating yarn made of conductive fiber material coated with a conductive material on the surface in the weft direction. And a plurality of conductive yarns arranged in place of the ground yarn and an electrode portion woven with the heat generating yarn, and the conductive yarn is a metal having a diameter of 10 μm to 100 μm on a core yarn made of an insulating fiber material A planar heating element which is a processed yarn having a resistance of 1 Ω / m to 50 Ω / m obtained by double- covering a thin wire .   The planar heating element according to claim 1, wherein the conductive yarn uses a yarn made of the same insulating fiber material as the ground yarn for the core yarn.   The planar heating element according to claim 1 or 2, wherein the conductive yarn is obtained by covering metal fibers with a winding number of 3,000 turns / m to 8,000 turns / m.   The planar heating element according to claim 1 or 2, wherein the heating yarn uses a conductive fiber material in which a carbon nanotube is coated on a surface of the same insulating fiber material as the ground yarn.

Images