JP2007184230A - Planar heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar heating element capable of making various dimensional designs, and excellent especially in bending properties and exothermic properties with regard to the planar heating element in which an electrode wire is sewn into a nonwoven fabric having conductivity. <P>SOLUTION: This is the planar heating element 10 in which at least two electrodes 12a, 12b made of a metal wire are separated from each other to be sewn into a conductive sheet 11 in which resin containing conductive powders are carried on the nonwoven fabric 14, in which the conductive sheet 11 and the electrodes 12a, 12b are pinched between insulating sheets 13a, 13b, and in which the nonwoven fabric 14 is constituted of fibers of which the average fiber diameter is 1 to 25 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a planar heating element in which electrode wires are sewn into a conductive non-woven fabric, and more particularly to a planar heating element excellent in flexibility and exothermicity.

  As a planar heating element in which electrode wires are sewn into a conductive nonwoven fabric, there is a planar heating element described in Patent Document 1, for example. In this sheet heating element, a composite yarn composed of a single metal fiber yarn and a fabric single yarn is woven as warps or wefts at both ends of a woven fabric serving as a sheet heating element, and the entire surface of the cloth is electrically conductive. A sheet heating element coated with a conductive paint, embedded under the road surface to prevent snow melting or freezing, and used as a heating element for heating and bedding in the home and for floor and attic heating in buildings Used as. However, in this planar heating element, since the electrodes are woven into the woven fabric as warp or weft, it is difficult to obtain planar heating elements of various dimensions, or the woven fabric electrode portion is thick. There was a problem that it was inferior in flexibility. Further, since the conductive paint is applied to the woven fabric, there is a problem that the amount of the conductive paint supported is small and the heat generation is inferior.

  Further, as a planar heating element obtained by improving the planar heating element, there is a planar heating element described in Patent Document 2, for example. This sheet heating element is a sheet heating element in which a plurality of metal fibers are sewn to both ends of a sheet obtained by impregnating a normal cloth made of warp and weft with a conductive resin agent such as carbon. It is possible to obtain planar heating elements with various dimensions. Moreover, the thickness of the sheet impregnated with the conductive resin agent is the same thickness at the center portion of the cloth and both end portions of the electrode portion, and can be curved. However, similarly to Patent Document 1, since this sheet heating element is impregnated with a conductive resin agent in a cloth composed of warp and weft yarns, the amount of the conductive resin agent carried is small and the heat generation is inferior. was there.

Japanese Utility Model Publication No. 03-84584 JP-A-11-214131

  The present invention relates to a planar heating element that solves the above-described problems and has electrode wires sewn into a conductive non-woven fabric, and various dimensional designs are possible, especially planar heating with excellent flexibility and exothermicity. The challenge is to provide a body.

  As illustrated in FIGS. 1A and 1B, a means for solving the problems of the present invention is that a conductive sheet 11 formed by carrying a resin containing conductive powder on a nonwoven fabric 14 is formed from a metal wire. At least two electrodes 12a and 12b are sewn apart, the conductive sheet 11 and the electrodes 12a and 12b are sandwiched between insulating sheets 13a and 13b, and the nonwoven fabric 14 has an average fiber diameter Is a sheet heating element 10 characterized by being composed of fibers of 1 to 25 μm.

  The present invention relates to a sheet heating element in which electrode wires are sewn into a conductive non-woven fabric, and various dimensional designs are possible. In particular, it is possible to provide a sheet heating element excellent in flexibility and heat generation. It became.

  As illustrated in FIGS. 1A and 1B, the planar heating element of the present invention includes at least two metal wires formed on a conductive sheet 11 in which a resin containing conductive powder is carried on a nonwoven fabric 14. The electrodes 12a and 12b are sewn apart. The nonwoven fabric 14 is not particularly limited as long as it is composed of fibers having an average fiber diameter of 1 to 25 μm. For example, a short fiber nonwoven fabric by a dry method, a long fiber nonwoven fabric by a spunbond method, a wet method nonwoven fabric, or the like is applied. Can do. Unlike a woven fabric, a non-woven fabric has a structure in which each fiber is randomly and oriented in a three-dimensional direction. Therefore, the nonwoven fabric is not only bulky but also has a large number of micropores obtained by crossing fibers. It is a porous body. On the other hand, a woven fabric has a structure in which a number of fibers are twisted into a yarn, and the yarn is regularly oriented in the two-dimensional direction in the vertical and horizontal directions. The number of holes obtained in this way is also very small. As described above, the porous nonwoven fabric can carry a large amount of the resin containing the conductive powder, and as a result, a planar heating element excellent in heat generation can be obtained. Further, as in the case of the woven fabric, voids in which the resin containing the conductive powder does not exist are formed in the vicinity of the crossing points of the respective fibers.

  The details of the form of the nonwoven fabric include, for example, a fiber called a normal staple fiber having an average fiber length of preferably 10 to 100 mm, more preferably 20 to 80 mm and a crimp number of 5 to 30 / inch. After forming into a fiber web using an apparatus or the like, by a method of bonding constituent fibers using an adhesive fiber by bonding, or by a method of bonding constituent fibers by bonding using an adhesive made of a synthetic resin, There is a nonwoven fabric obtained by a manufacturing method generally called a dry method. As an aspect of the adhesive fiber, (1) an aspect in which the synthetic fiber is composed of only one resin component, (2) an aspect (core-sheath type or sea-island type) coated with one or more resin components, or one An aspect (side-by-side type or the like) in which the above resin component and fusion component are arranged next to each other is applicable. The melting point of the fusion component or adhesive component is preferably 20 ° C. or more lower than the melting point of the non-fusion component or non-adhesion component, more preferably 30 ° C. or more, and still more preferably 40 ° C. or more. Moreover, the nonwoven fabric formed not only by a dry method but by the manufacturing method of arbitrary nonwoven fabrics, for example, a wet method, a spun bond method, a melt blow method, an electrostatic spinning method, a flash spinning method etc. is applicable.

  In the case of a wet method, for example, using a paper machine of a horizontal long net method, an inclined wire type short net method, a circular net method, or a long net / circular net combination method, the average fiber length is preferably 1 to 20 mm, More preferably, a method of rolling up a fiber sheet from a slurry containing 3 to 15 mm of synthetic fiber or the like can be employed. Specifically, there is a method in which constituent fibers are bonded to a fiber sheet after paper making using an adhesive. Alternatively, there is a method in which an adhesive fiber having a melting point or a softening point lower than that of the main fiber is mixed in the slurry, and the constituent fibers are bonded to each other using the adhesive fiber after paper making.

  In the case of the spunbond method, for example, there is a method in which synthetic fibers are spun from a nozzle to form a fiber fleece made of long fibers, and then the constituent fibers are bonded by using an adhesive made of a synthetic resin. Alternatively, there is a method in which core-sheath type long fibers made of two kinds of resin components having different melting points are spun from a nozzle, and then the constituent fibers are bonded by bonding using a low melting point sheath component as an adhesive component. Further, when a synthetic fiber is spun from a nozzle into a fiber fleece made of a long fiber, an adhesive staple fiber made of a synthetic resin is blown into a fiber fleece in which the long fiber and the short fiber are integrated, and then configured. There is a method of bonding fibers by bonding.

  In the case of the electrostatic spinning method or the flash spinning method, for example, a synthetic fiber is spun from a nozzle to form a fiber fleece, and then a constituent fiber is bonded by using an adhesive made of a synthetic resin. .

  Moreover, in these nonwoven fabric manufacturing methods, it is also possible to use a method in which fibers are entangled with each other by the action of a needle or a water flow to bond the fibers to the formed fiber web, fiber sheet, or fiber fleece. Moreover, it is also possible to use together the method of couple | bonding fibers by heat sealing | fusion entirely or partially using a heating roll. When fibers are bonded using an adhesive or adhesive fibers, the structure of the nonwoven fabric itself becomes hard, and the conductive sheet in which the resin containing conductive powder is supported on the nonwoven fabric is also relatively hard. In some cases, the sheet heating element is slightly inferior in flexibility. On the other hand, according to the method in which fibers are entangled with each other by the action of a needle or water flow to the above-mentioned fiber fleece, the structure of the nonwoven fabric itself has flexibility. The conductive sheet on which the resin containing is carried is also relatively flexible and has the effect of becoming a planar heating element with excellent flexibility.

  The type of fiber constituting the nonwoven fabric is not particularly limited as long as it can be used according to the production method of the nonwoven fabric. For example, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, nylon 6, nylon 66, and the like. Polyamide fibers such as polyamide fibers, polypropylene and polyethylene, acrylic fibers such as polyacrylonitrile, and synthetic fibers such as polyvinyl alcohol fibers, as well as semi-synthetic fibers such as rayon, and natural fibers such as cotton and pulp fibers be able to.

  In this invention, the average fiber diameter of the constituent fiber contained in the said nonwoven fabric is 1-25 micrometers, Preferably it is 4-20 micrometers. When the average fiber diameter is less than 1 μm, the pore diameter of the nonwoven fabric becomes too small, and the resin containing the conductive powder hardly penetrates into the nonwoven fabric. When the average fiber diameter exceeds 20 μm, the pore diameter of the nonwoven fabric becomes too large, It becomes difficult for the resin containing the conductive powder to be sufficiently supported on the nonwoven fabric. Moreover, in order to make a structure rich in durability, the average fiber diameter of the constituent fibers is preferably 1 to 15 μm, more preferably 4 to 10 μm. By being such a relatively fine fiber, the structure of the nonwoven fabric is strong against tension and strong against tearing. Therefore, a conductive sheet in which a resin containing conductive powder is supported on this nonwoven fabric is also strong against tension, In addition, there is an effect that the sheet heating element is strong against tearing and has excellent flexibility and durability.

  Moreover, although the average fiber diameter of the constituent fiber contained in the said nonwoven fabric is 1-25 micrometers, it can also achieve by having a fiber diameter of 7 micrometers or less to have such an average fiber diameter. In particular, when the average fiber diameter is 1 to 7 μm, it is essential to include ultrafine fibers having a fiber diameter of 7 μm or less. In addition, in order to include ultrafine fibers having a fiber diameter of 7 μm or less, it is difficult to use the ultrafine fibers as they are in the dry method and the spunbond method in the above-mentioned nonwoven fabric production method. A method of generating ultrafine fibers by dividing fibers simultaneously with hydroentanglement using a splittable composite fiber having a functional resin component can be applied. Further, in the wet method, melt blow method, electrostatic spinning method or flash spinning method in the above-mentioned nonwoven fabric production method, the ultrafine fibers can be used as they are. However, in the wet method, the strength of the conductive sheet is inferior because the fiber length is short, and in the melt blow method and the electrospinning method, the fiber is not stretched, so that the crystallization does not progress and the strength of the conductive sheet is inferior. Compared with this, the dry method and the spunbond method have the effect of being excellent in the strength of the conductive sheet because the fiber length is long, and in particular, the fibers produced by splitting the ultrafine fibers from the split fibers of the long fibers. It is preferable that

  The splittable fiber is a fiber composed of a splittable composite fiber in which two or more types of fiber-forming resin components are combined, and as long as the splittable fiber can be split by the action of water flow, or elutes a component that dissolves with a solvent. The cross-sectional shape of the splittable fiber is not particularly limited as long as it can be divided by, for example, there are forms shown in (a) to (d) of FIG. Among these cross-sectional shapes, the orange shape shown in (a) and (c) is preferable because it can be easily divided and the fiber strength after the division can be increased. The number of divisions of the splittable fiber is not limited, and may be two or more. For example, about 6 to 20 divisions are preferable.

  The type of fiber-forming resin that constitutes the splittable fiber is not particularly limited. For example, polyamide resin (for example, 6 nylon, 66 nylon, etc.), polyester resin (for example, polyethylene terephthalate, polybutylene). Terephthalate, etc.), polyolefin resins (for example, polyethylene, polypropylene, etc.), polyvinylidene chloride resins, and the like. Among these, it is preferable to select at least a polyester-based resin as one component because high strength, excellent heat resistance, and excellent durability can be imparted.

  The thickness of the splittable fiber is not particularly limited as long as spinning conditions and splittability are taken into consideration, and the fiber diameter is preferably 1 to 100 μm, and more preferably 20 to 50 μm. Moreover, 1-10 micrometers is preferable, as for the fiber diameter after a division | segmentation, 1-7 micrometers is more preferable, and 1-5 micrometers is still more preferable. The fiber diameter before or after division can be the diameter of a circle having the same area as the cross section of the fiber.

  The nonwoven fabric containing ultrafine fibers generated by dividing the splittable fiber by the action of a water stream is a stream of water jetted from a nozzle head in which high-pressure water is built up by a fiber web composed of fibers containing the splittable fiber. It is a nonwoven fabric formed by the action of the splitting fibers in the fiber web being split and the constituent fibers being intertwined. The fiber web may be composed of only the splittable fibers or may include other non-splitable fibers other than the splittable fibers.

  In order to divide the splittable fiber in the fiber web by the action of a water flow sprayed from a nozzle head containing high-pressure water, it is possible to use a method of producing a nonwoven fabric by a normal water flow entanglement, for example, the fiber The web is placed on a perforated support made of a belt conveyor and the number of nozzle heads containing high-pressure water installed on the top of the fiber web while moving the perforated support is larger. There is a method in which a columnar flow is ejected through a nozzle plate in which nozzle holes are arranged linearly, and a water flow is applied to the fiber web. The diameter of the nozzle holes used in this method is preferably 0.1 to 0.3 mm, the interval between the nozzle holes is preferably 0.5 to 2 mm, and a plurality of nozzle heads are preferably used. The water pressure in the nozzle head is preferably 0.2 to 2 MPa, and for dividing the splittable fiber, 0.5 to 2 MPa is preferable although it depends on the degree of splitting.

Moreover, 20-300 g / m < ² > is preferable, as for the surface density of the said nonwoven fabric, 30-250 g / m < ² > is more preferable, and 40-200 g / m < ² > is still more preferable. If it is less than 20 g / m ² , the amount of the resin containing conductive powder may be reduced, and heat generation may be reduced. If it exceeds 300 g / m ² , it may take too much time to sew the electrode. , Flexibility may be reduced. Further, the thickness of the nonwoven fabric is not particularly limited as long as it is possible to sew an electrode made of a metal wire, and is preferably 0.03 to 2 mm, more preferably 0.05 to 1.5 mm, 0.1-1.0 mm is still more preferable. If the thickness is less than 0.03 mm, the amount of the resin containing the conductive powder is reduced, and the heat build-up may be reduced. If the thickness exceeds 2 mm, it takes too much time to sew the electrode, and the flexibility is low. May decrease. The thickness is the thickness specified in the 6.1.2A method of JIS L1913-1998. However, the load is 2.0 kPa.

Moreover, when the tensile strength of the nonwoven fabric is expressed as an average value in the longitudinal direction and the transverse direction, the value converted to an areal density of 100 g / m ² is preferably 100 N / 50 mm width or more, and 150 N / 50 mm width or more. More preferably, it is more preferably 200 N / 50 mm width or more. Moreover, when the tear strength of the nonwoven fabric is expressed as an average value in the longitudinal direction and the transverse direction, a value converted to an areal density of 100 g / m ² is preferably 2N or more, and more preferably 3.5N or more. Preferably, 5N or more is more preferable. When the nonwoven fabric contains ultrafine fibers generated by splitting from splittable fibers, a tear strength of 3.5 N or more can be easily obtained. In addition, let the tensile strength be the tensile strength prescribed | regulated to 6.3 of JISL1913-1998. The tear strength is the tear strength specified in 6.4.3 (single tongue method) of JIS L1913-1998.

  In addition, the bending resistance (cantilever method) of the nonwoven fabric is preferably 300 mm or less, and more preferably 250 mm or less in terms of an average value in the vertical direction and the horizontal direction. In particular, in a field where flexibility is required, it is preferably 160 mm or less, and more preferably 100 mm or less. The bending resistance is the bending resistance defined by the 8.19.1A method (45 ° cantilever method) of JIS L1096-1999.

  In the present invention, a resin containing conductive powder is supported on the nonwoven fabric. The conductive powder is not particularly limited as long as it is conductive powder, and for example, carbon or graphite powder can be preferably applied. The carbon or graphite used for the conductive powder is preferably spherical, shell-like, scale-like, needle-like, or fiber-like particles having an average particle size of 0.5 to 500 μm.

  The resin containing conductive powder can also contain rubber such as natural rubber and synthetic rubber, and as the resin, a synthetic resin such as a thermoplastic resin and a thermosetting resin can be applied. Polyacrylic resins, polyester resins, epoxy resins, polyamide resins, polyimide resins, polyolefin resins, polyether / etherketone resins, polyphenylene sulfide resins, silicone resins, and the like can be applied. Moreover, as a compounding quantity of the electroconductive powder with respect to the said resin, 20-1000 mass parts is preferable with respect to 100 mass parts of resin, for example, 30-800 mass parts is more preferable, 50-500 mass parts is still more preferable.

  In order to make a conductive conductive sheet carrying a resin containing conductive powder on the nonwoven fabric, specifically, for example, the resin in the form of a powder or an emulsion type dispersion and the conductive powder Is dispersed in a solvent such as water, and a thickener, a surfactant, etc. is added, and the non-woven fabric is impregnated with a thickened paste-form compounded liquid or applied by coating. Sheet 11 can be obtained.

  Moreover, as an adhesion amount of the said resin containing the electroconductive powder with respect to the said nonwoven fabric, 30-400 mass parts is preferable with respect to 100 mass parts of nonwoven fabric, 50-300 mass parts is more preferable, 60-250 mass parts is still more preferable. .

  The shape of the conductive sheet is not particularly limited, and for example, a rectangular shape and other polygonal shapes can be applied as illustrated in FIG. 1A, but a rectangular shape is preferable in terms of heat generation efficiency. Moreover, although the dimension and area are not specifically limited, In the case of a rectangle, it is preferable that one side is 2-35 cm, it is more preferable that it is 3-25 cm, and it is still more preferable that it is 4-15 cm. If one side is less than 2 cm, the flexibility may be inferior, and if it exceeds 35 cm, the voltage between the electrodes becomes too high, which may be inconvenient for use such as clothing or portable use.

  In the present invention, the electrodes 12a and 12b are composed of metal wires, and a metal wire in which thin conductive metal strands are bundled or a twisted wire obtained by twisting metal strands is used. The conductive sheet 11 is sewn so as to penetrate the front and back surfaces. In addition to the metal wires, it is also possible to use stranded wires combined with organic fibers such as synthetic fibers, semi-synthetic fibers, and natural fibers. Further, the number of the metal wires is not particularly limited, and may be one as illustrated in FIG. 1 or may be plural as illustrated in FIG. In the case of one, it is suitable for applications where the heat generation temperature is relatively low, and is also suitable for a relatively small sheet piece. Further, the manufacturing process is simplified and the cost can be kept low. There is. Moreover, when there are a plurality of sheets, it is suitable for an application having a relatively high heat generation temperature, and also suitable for a relatively large sheet piece.

  As the conductive wire, for example, a wire drawn from a metal material having a low electrical resistance such as copper, silver, aluminum, tin, the same electrical resistance such as copper, silver, aluminum, tin on the surface of synthetic fiber or natural fiber An element wire plated with a small metal material can be applied. The wire diameter of the conductive element wire is preferably 0.01 to 0.5 mm, and more preferably 0.03 to 0.3 mm. The number of conductive wires constituting the stranded wire is preferably 2 to 100, more preferably 2 to 25. The interval between the seams is preferably 1 to 10 mm, and can be sewn with an industrial sewing machine or the like.

  In the present invention, as illustrated in FIGS. 1A and 1B, at least two electrodes 12 a and 12 b are sewn into the conductive sheet 11 at a distance. Although the degree of separation depends on the size of the conductive sheet 11, specifically, the distance between the center lines of the electrodes 12 a and 12 b is preferably 1 to 30 cm, preferably 2 to 20 cm, 10 cm is more preferable. If it is less than 1 cm, the number of electrodes becomes too large and the flexibility may be rather poor. On the other hand, if it exceeds 30 cm, the voltage between the electrodes becomes too high, which may be inconvenient for clothing or portable use. .

  In the present invention, as illustrated in FIGS. 1A and 1B, the conductive sheet 11 and the electrodes 12a and 12b are sandwiched between electrically insulating sheets 13a and 13b. The insulating sheet is not particularly limited as long as the conductive sheet 11 and the electrodes 12a and 12b can be sandwiched. For example, a resin plate or a film made of a thermoplastic resin can be applied to one or both. . In particular, the insulating sheet is preferably a film made of a laminateable thermoplastic resin. For example, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as nylon 6 and nylon 66, polypropylene, Examples thereof include films made of polyolefin resins such as polyethylene and polyethylene vinyl acetate copolymer, acrylic resins such as polyacrylonitrile, polyvinyl acetate resins, and polyvinyl alcohol resins. It is also possible to apply a laminated film made of a combination of these resins, or a composite film made of a laminated film made of these resins and other materials such as woven or knitted fabric and nonwoven fabric. For example, polyethylene terephthalate resin and polyethylene A laminated film composed of a combination with a vinyl acetate copolymer resin can be exemplified. Moreover, when especially electrical insulation and heat resistance are required, films, such as a fluorine resin and a silicon resin, can be mentioned, for example.

  The thickness of the film is not particularly limited, and may be appropriately selected according to the material of the film and the required flexibility. For example, the thickness is preferably 10 to 150 μm, more preferably 15 to 100 μm, and still more preferably 20 to 70 μm. If it is less than 10 μm, it may deteriorate due to repeated bending, and if it exceeds 150 μm, it may be inferior in flexibility.

  The method of sandwiching the conductive sheet 11 and the electrodes 12a and 12b with the insulating sheet is not particularly limited. For example, the insulating sheet is bonded with an adhesive or a heat-adhesive resin powder. It is also possible to coat with a laminate, but a laminate coating is preferred. Specifically, by sandwiching the conductive sheet 11 and the electrodes 12a and 12b between two insulating sheets made of thermoplastic resin, and then passing between a pair of heating rolls, heating and pressurizing. It can be laminated with an insulating sheet.

  In the present invention, the method of joining the electrodes 12a and 12b and the lead wire 19 is not particularly limited, and as shown in FIG. 1 (a), the conductive material is formed near the ends of the electrodes 12a and 12b. There is a method in which a terminal 17 made of a metal material is attached and a lead wire 19 is connected to the terminal 17. The terminal 17 is attached by passing a rivet 171 made of a conductive metal material through the electrode, the conductive sheet, and the film from above the sandwiched film. It is attached. In the example of this figure, the terminals 17 and part of the lead wires 19 are further covered with an insulating tape 18.

  The sheet heating element of the present invention is particularly exothermic because at least two electrodes made of metal wires are sewn into a conductive sheet formed by carrying a resin containing conductive powder on a nonwoven fabric. This planar heating element can be heated with a relatively low applied voltage, for example, a low applied voltage of 30 V or less. More specifically, for example, even at a low voltage of about 1.2V to 24V, the temperature is preferably 20 to 150 ° C, more preferably 20 to 100 ° C, and still more preferably 20 to 80 ° C. Can do. Therefore, as a power source, a sufficiently high exothermic temperature can be obtained not only for a commercial high voltage AC power source such as 100 V but also for a low voltage such as a battery (dry battery or the like). Therefore, the present invention is not limited to a stationary planar heating element, but can also be applied to a portable and small planar heating element, and is particularly suitable for clothes having flexibility.

  Note that the use of the planar heating element of the present invention is not particularly limited, and is a heating device having a planar or curved heating portion, such as a heat retaining plate, a heater, a road, a roof, or the like. The present invention can be widely applied to snow melting devices, heating devices such as floors, walls, carpets and blankets, cold protection clothing, sports clothing, work clothes, insoles, warming waist wraps, and warming pouchettes. In addition, as described above, since it is possible to generate heat even with a low-voltage battery, and because it is excellent in flexibility, it is particularly used in applications in which bending or bending repeatedly occurs, such as an application used with clothing, or an application having a large degree of bending. Is suitable.

  Examples of the present invention will be described below, but these are only suitable examples for facilitating understanding of the invention, and the present invention is not limited to the contents of these examples.

(Example 1)
In Example 1, a sheet heating element having the form shown in FIGS. 1A and 1B was manufactured by the following process.
In order to prepare a nonwoven fabric carrying a resin containing conductive powder, a 2.4 decitex composite fiber (fiber diameter 12 μm, having a cross-sectional form shown in FIG. Resin component 1 was polyester resin and resin component 2 was 6 nylon resin) was spun from a nozzle to form a fiber web composed of splittable long fibers. Next, the fiber web was placed on an open support, a columnar flow was ejected from a nozzle head containing high-pressure water, the water flow was applied to the fiber web, and the fiber web was dried with a dryer. . As a result, the splittable long fibers are split by the action of the water flow, and a maximum of 16 ultrafine fibers are generated from each fiber. The generated ultrafine fibers are entangled by the action of the water flow, and the average fiber diameter is 3.1 μm. A non-woven fabric having a thickness of 0.50 mm and a surface density of 100 g / m ² was obtained. The nonwoven fabric had a tensile strength of 250 N / 50 mm in average in the machine direction and the transverse direction, and a tensile elongation at break of 42% in the longitudinal and transverse directions. Moreover, the average value of the longitudinal direction and the horizontal direction was 6.5 N for the tear strength, and the average value of the bending resistance was 100 mm in the vertical direction and the horizontal direction.
Next, as a resin containing conductive powder, a powder made of carbon or graphite and an emulsion type dispersion of a copolymer of acrylic ester and styrene are dispersed in water, and a thickener and a surfactant are added. Then, a blended liquid was prepared by increasing the viscosity.
Next, the non-woven fabric is impregnated with the compounded liquid using a pair of rubber rolls, and then dried at 120 ° C. for 5 minutes in two steps. Conductivity containing 140 g / m ^{2 of} resin containing conductive powder. Sex sheet was obtained. The surface density of this conductive sheet was 240 g / m ² and the thickness was 0.70 mm. Next, as shown in FIG. 1A, the conductive sheet 11 cut into a size of 5 cm wide × 11 cm long was produced.
Next, one metal wire composed of six strands of copper wire having a wire diameter of 0.08 mm is sewn into the conductive sheet 11 with an industrial sewing machine in two rows so that the seam spacing is about 2 mm. 2 electrodes 12a and 12b. The two electrodes were provided so as to be 4 cm apart.
Next, this laminated film 2 with the polyethylene vinyl acetate copolymer resin side of the electrically insulating laminated film (thickness: 35 μm) laminated with polyethylene terephthalate resin and polyethylene vinyl acetate copolymer resin (melting point: about 100 ° C.) as the inner side. The conductive sheet 11 and the electrodes 12a and 12b were sandwiched between sheets, then passed between a pair of heating rolls, and heated and pressed to laminate with an insulating sheet.
Next, as shown in FIG. 1A, a terminal 17 made of a conductive metal material was attached in the vicinity of the ends of the electrodes 12a and 12b, and a lead wire 19 was connected to the terminal 17. The terminal 17 is attached by passing a rivet 171 made of a conductive material from above the sandwiched film through the electrode, the conductive sheet, and the film, and attaching the terminal 17 by the rivet 171. It was. Next, the terminal 17 and the lead wire were further covered with an insulating tape 18 to obtain a planar heating element.
When a voltage of DC 7V was applied to the lead wire of the obtained sheet heating element for 2 minutes, the surface temperature of the sheet heating element was 69 ° C. at a room temperature of 26 ° C.
Moreover, this planar heating element is suitable for applications in which bending and bending repeatedly occur, for example, for use with clothing, or for applications with a large degree of bending. Moreover, since this planar heating element was formed from splittable long fibers, it was excellent in tensile strength and tear strength and excellent in durability.

(Example 2)
In Example 2, a sheet heating element having the form shown in FIGS. 2A and 2B was manufactured by the following steps.
In order to prepare a nonwoven fabric carrying a resin containing conductive powder, a 2.4 decitex composite fiber (fiber diameter 12 μm, having a cross-sectional form shown in FIG. Resin component 1 was polyester resin and resin component 2 was 6 nylon resin) was spun from a nozzle to form a fiber web composed of splittable long fibers. Next, the fiber web was placed on an open support, a columnar flow was ejected from a nozzle head containing high-pressure water, the water flow was applied to the fiber web, and the fiber web was dried with a dryer. . As a result, the splittable long fibers are split by the action of the water flow, and a maximum of 16 ultrafine fibers are generated from each fiber. The generated ultrafine fibers are entangled by the action of the water flow, and the average fiber diameter is 3.1 μm. A non-woven fabric having a thickness of 0.50 mm and a surface density of 100 g / m ² was obtained. The nonwoven fabric had a tensile strength of 250 N / 50 mm in average in the machine direction and the transverse direction, and a tensile elongation at break of 42% in the longitudinal and transverse directions. Moreover, the average value of the longitudinal direction and the horizontal direction was 6.5 N for the tear strength, and the average value of the bending resistance was 100 mm in the vertical direction and the horizontal direction.
Next, as a resin containing conductive powder, a powder made of carbon or graphite and an emulsion type dispersion of a copolymer of acrylic ester and styrene are dispersed in water, and a thickener and a surfactant are added. Then, a blended liquid was prepared by increasing the viscosity.
Next, the non-woven fabric is impregnated with the compounded liquid using a pair of rubber rolls, and then dried at 120 ° C. for 5 minutes in two steps. Conductivity containing 140 g / m ^{2 of} resin containing conductive powder. Sex sheet was obtained. The surface density of this conductive sheet was 240 g / m ² and the thickness was 0.70 mm. Next, as shown in FIG. 2A, the conductive sheet 11 cut into a size of 5 cm wide × 11 cm long was produced.
Next, three metal wires made of six strands of copper wire having a wire diameter of 0.08 mm are opened at an interval of about 0.8 mm, and the conductive sheet 11 with an industrial sewing machine has a seam interval of about 2 mm. Thus, two electrodes 12a and 12b were sewn in two rows. The two electrodes were provided so as to be 4 cm apart.
Next, this laminated film 2 with the polyethylene vinyl acetate copolymer resin side of the electrically insulating laminated film (thickness: 35 μm) laminated with polyethylene terephthalate resin and polyethylene vinyl acetate copolymer resin (melting point: about 100 ° C.) as the inner side. The conductive sheet 11 and the electrodes 12a and 12b were sandwiched between sheets, then passed between a pair of heating rolls, and heated and pressed to laminate with an insulating sheet.
Next, as shown in FIG. 2A, a terminal 17 made of a conductive metal material was attached in the vicinity of the ends of the electrodes 12 a and 12 b, and a lead wire 19 was connected to the terminal 17. The terminal 17 is attached by passing a rivet 171 made of a conductive material from above the sandwiched film through the electrode, the conductive sheet, and the film, and attaching the terminal 17 by the rivet 171. It was. Next, the terminal 17 and the lead wire were further covered with an insulating tape 18 to obtain a planar heating element.
When a voltage of DC 7V was applied to the lead wire of the obtained sheet heating element for 2 minutes, the surface temperature of the sheet heating element was 70 ° C. at a room temperature of 26 ° C.
Moreover, this planar heating element is suitable for applications in which bending and bending repeatedly occur, for example, for use with clothing, or for applications with a large degree of bending. Moreover, since this planar heating element was formed from splittable long fibers, it was excellent in tensile strength and tear strength and excellent in durability.

Example 3
In order to prepare a nonwoven fabric carrying a resin containing conductive powder, as a splittable short fiber, 2.2 dtex composite staple fiber (fiber diameter 12 μm × 38 mm length, having the cross-sectional form shown in FIG. A resin component 1 is a polyester resin, and a resin component 2 is a 6 nylon resin). A fiber fleece is produced, and the fiber fleece is folded to form a cross-lay fiber web. Next, the fiber web was placed on an open support, a columnar flow was ejected from a nozzle head containing high-pressure water, the water flow was applied to the fiber web, and the fiber web was dried with a dryer. . The water pressure was 15 MPa and a plurality of nozzle heads were used. As a result, the splittable short fibers are split by the action of the water stream, and a maximum of 13 ultrafine fibers are generated from each fiber. The generated ultrafine fibers are entangled by the action of the water stream, and the average fiber diameter is 3.3 μm. A non-woven fabric having a thickness of 0.44 mm and a surface density of 85 g / m ² was obtained. Further, the tensile strength of this nonwoven fabric was 180 N / 50 mm in width in the longitudinal and transverse directions, and the tensile elongation at break was 60% in the longitudinal and transverse directions. In addition, the average value of the tear strength in the vertical direction and the horizontal direction was 4.1 N, and the bending resistance was 70 mm in the average value in the vertical direction and the horizontal direction.
Next, as a resin containing conductive powder, a powder made of carbon or graphite and an emulsion type dispersion of a copolymer of acrylic ester and styrene are dispersed in water, and a thickener and a surfactant are added. Then, a blended liquid was prepared by increasing the viscosity.
Next, the non-woven fabric is impregnated with the compounded liquid using a pair of rubber rolls and then dried at 120 ° C. for 5 minutes in two steps, and the conductive material containing 114 g / m ^{2 of} resin containing conductive powder is contained. Sex sheet was obtained. The surface density of this conductive sheet was 198 g / m ² and the thickness was 0.60 mm. Next, as shown in FIG. 2A, the conductive sheet 11 cut into a size of 6 cm wide × 17 cm long was produced.
Next, three metal wires made of six strands of copper wire having a wire diameter of 0.08 mm are opened at an interval of about 0.8 mm, and the conductive sheet 11 with an industrial sewing machine has a seam interval of about 2 mm. Thus, two electrodes 12a and 12b were sewn in two rows. The two electrodes were provided so as to be 5 cm apart.
Next, this laminated film 2 with the polyethylene vinyl acetate copolymer resin side of the electrically insulating laminated film (thickness: 35 μm) laminated with polyethylene terephthalate resin and polyethylene vinyl acetate copolymer resin (melting point: about 100 ° C.) as the inner side. The conductive sheet 11 and the electrodes 12a and 12b were sandwiched between sheets, then passed between a pair of heating rolls, and heated and pressed to laminate with an insulating sheet.
Next, as shown in FIG. 2A, a terminal 17 made of a conductive metal material was attached in the vicinity of the ends of the electrodes 12 a and 12 b, and a lead wire 19 was connected to the terminal 17. The terminal 17 is attached by passing a rivet 171 made of a conductive material from above the sandwiched film through the electrode, the conductive sheet, and the film, and attaching the terminal 17 by the rivet 171. It was. Next, the terminal 17 and the lead wire were further covered with an insulating tape 18 to obtain a planar heating element.
When a DC voltage of 12 V was applied to the obtained lead wire of the planar heating element for 2 minutes, the surface temperature of the planar heating element was 78 ° C. at a room temperature of 26 ° C.
Moreover, this planar heating element is suitable for applications in which bending and bending repeatedly occur, for example, for use with clothing, or for applications with a large degree of bending. Moreover, since this planar heating element was formed from splittable fibers, it was excellent in tensile strength and tear strength and excellent in durability.

Example 4
In order to prepare a nonwoven fabric carrying a resin containing conductive powder, 2.2 decitex staple fibers (polyester fiber, fiber diameter 14 μm × 38 mm length) were 70% by mass, 1.7 decitex staple fibers (rayon fibers, 20 mass% of fiber diameter 12 μm × 40 mm length), 1.7 dtex adhesive staple fiber (side-by-side type composite fiber, fiber diameter 12 μm × 51 mm length, resin component 1 is polypropylene resin, resin component 2 is polyethylene resin) A fiber raw material mixed with 10% by mass was supplied to a card machine to prepare a fiber fleece, and the fiber fleece was folded to form a cross lay fiber web. Next, the fiber web was placed on an open support, a columnar flow was ejected from a nozzle head containing high-pressure water, the water flow was applied to the fiber web, and the fiber web was dried with a dryer. . The water pressure was 12 MPa and a plurality of nozzle heads were used. As a result, the fiber web was entangled by the action of water flow, and a nonwoven fabric having a thickness of 0.44 mm and an area density of 65 g / m ² was obtained, which was made of fibers having an average fiber diameter of 14 μm. Further, the tensile strength of the nonwoven fabric was 110 N / 50 mm in width in the longitudinal and transverse directions, and the tensile elongation at break was 77% in the longitudinal and transverse directions. The tear strength was 2.7 N in the average value in the vertical and horizontal directions, and the bending resistance was 50 mm in the average value in the vertical and horizontal directions.
Next, as a resin containing conductive powder, a powder made of carbon or graphite and an emulsion type dispersion of a copolymer of acrylic ester and styrene are dispersed in water, and a thickener and a surfactant are added. Then, a blended liquid was prepared by increasing the viscosity.
Next, the non-woven fabric is impregnated with the compounded liquid using a pair of rubber rolls and then dried at 120 ° C. for 5 minutes in two steps, and conductive containing 108 g / m ^{2 of} resin containing conductive powder is performed. Sex sheet was obtained. The surface density of this conductive sheet was 173 g / m ² and the thickness was 0.55 mm. Next, as shown in FIG. 2A, the conductive sheet 11 cut into a size of 6 cm wide × 17 cm long was produced.
Next, three metal wires made of six strands of copper wire having a wire diameter of 0.08 mm are opened at an interval of about 0.8 mm, and the conductive sheet 11 with an industrial sewing machine has a seam interval of about 2 mm. Thus, two electrodes 12a and 12b were sewn in two rows. The two electrodes were provided so as to be 5 cm apart.
Next, this laminated film 2 with the polyethylene vinyl acetate copolymer resin side of the electrically insulating laminated film (thickness: 35 μm) laminated with polyethylene terephthalate resin and polyethylene vinyl acetate copolymer resin (melting point: about 100 ° C.) as the inner side. The conductive sheet 11 and the electrodes 12a and 12b were sandwiched between sheets, then passed between a pair of heating rolls, and heated and pressed to laminate with an insulating sheet.
Next, as shown in FIG. 2A, a terminal 17 made of a conductive metal material was attached in the vicinity of the ends of the electrodes 12 a and 12 b, and a lead wire 19 was connected to the terminal 17. The terminal 17 is attached by passing a rivet 171 made of a conductive material from above the sandwiched film through the electrode, the conductive sheet, and the film, and attaching the terminal 17 by the rivet 171. It was. Next, the terminal 17 and the lead wire were further covered with an insulating tape 18 to obtain a planar heating element.
When a voltage of DC 10 V was applied to the lead wire of the obtained planar heating element for 2 minutes, the surface temperature of the planar heating element was 62 ° C. at a room temperature of 26 ° C.
Moreover, this planar heating element is suitable for applications in which bending and bending repeatedly occur, for example, for use with clothing, or for applications with a large degree of bending.

(A) is a top view which shows an example of the planar heating element by this invention, (b) is typical sectional drawing of the B-B 'line | wire of (a). (A) is a top view which shows another example of the planar heating element by this invention, (b) is typical sectional drawing of the A-A 'line of (a). (A) is an example of the cross section of the splittable fiber used in the present invention, (b) is another example of the cross section of the splittable fiber used in the present invention, and (c) is another cross section of the splittable fiber used in the present invention. An example and (d) are figures which show another example of the cross section of the splittable fiber used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin component 2 Other resin component 10 Planar heating element 11 Conductive sheet 12a, 12b Electrode 13a, 13b Electrical insulating sheet 14 Non-woven fabric 17 Terminal 171 Rivet 18 Electrical insulating tape 19 Lead wire

Claims (7)

  At least two electrodes made of metal wires are sewn into a conductive sheet in which a resin containing conductive powder is supported on a nonwoven fabric, and the conductive sheet and the electrode are sandwiched between insulating sheets. The sheet heating element is characterized in that the nonwoven fabric is composed of fibers having an average fiber diameter of 1 to 25 μm.   The planar heating element according to claim 1, wherein the metal wire includes a plurality of metal wires.   The planar heating element according to claim 1 or 2, wherein the nonwoven fabric contains ultrafine fibers having a fiber diameter of 7 µm or less.   The planar heating element according to claim 3, wherein the ultrafine fibers are fibers generated by splitting from splittable fibers.   The planar heating element according to claim 3 or 4, wherein the splittable fibers are splittable long fibers.   The planar heating element according to any one of claims 1 to 5, wherein the bending resistance of the nonwoven fabric by a cantilever method is 300 mm or less. The tear strength of the nonwoven fabric, the surface density of 100 g / m ² per sheet heating element according to any one of claims 1 to 6, wherein the at least 2N.

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