Heater wire support substrate

Abstract

The heater wire holding substrate (11) includes a nonwoven fabric layer (31) including a nonwoven fabric (21), and a heat-sealable resin layer (32) including an extruded heat-sealable resin material (22) and heat-sealed onto the nonwoven fabric layer (31). The heat-sealed nonwoven fabric layer (31) and heat-sealable resin layer (32) have a plurality of recesses (33) in which the heat-sealable resin layer (32) penetrates in the depth direction of the nonwoven fabric layer (31). The recesses (33) form a mixed fixed layer (41) in which the nonwoven fabric (21) and the heat-sealable resin material (22) are mixed. In the recesses (33), the amount of sinking of the surface of the nonwoven fabric layer (31) is 10 μm or more and is equal to or less than the thickness dimension of the heat-sealable resin layer (32).

Description

[Technical field]

[0001] The present invention relates to a heater wire holding substrate. [Background technology]

[0002] Generally, a sheet heater having a cord-shaped heating element fixed to various substrates is known. One form of such sheet heater is widely known as an electric carpet, which has been in practical use for a long time. An electric carpet has a structure in which, for example, a heat-sealing layer is provided on the surface of a heat insulating substrate such as a thick nonwoven fabric such as felt or polyurethane foam, a cord-shaped heating element having a heat-sealing layer on its surface is arranged in a meandering manner on top of the heat-sealing layer, and a skin is further provided on top of the layer, and the laminate is fused and fixed by thermocompression. Also known is a sewn-type sheet heater in which a cord-shaped heating element is sewn and fixed to a nonwoven fabric or the like.

[0003] When a sheet heater is used as a seat heater for an automobile, a nonwoven fabric substrate thinner than that of an electric carpet may be used. For example, Patent Document 1 discloses a sheet heater used as a seat heater for an automobile. A sheet heater for an automobile has a structure in which a sheet heater is fixed to, for example, an insulating seat cushion with a double-sided adhesive tape, and a skin cover is placed on top of the sheet heater without being fixed. Such a sheet heater is required to have various performances such as quick heating, uniform heating, energy saving, bending durability, and contact sensation. In particular, electric vehicles, which have been rapidly popular in recent years, are required to have excellent energy saving performance in order to extend the driving distance per charge and maintain heating during snowy traffic jams. For such a sheet heater to have high performance, the heater wire holding substrate that fixes the cord-shaped heating element is also required to have excellent performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2003-174952 Summary of the Invention

[0005] An object of the present invention is to provide an excellent heater wire holding substrate.

[0006] According to one aspect of the present invention, a heater wire holding substrate comprises a nonwoven fabric layer containing a nonwoven fabric, and a heat-fusible resin layer containing an extruded heat-fusible resin material and heat-fusible on the nonwoven fabric layer, the heat-fusible nonwoven fabric layer and the heat-fusible resin layer having a plurality of recesses in which the heat-fusible resin layer penetrates in a depth direction of the nonwoven fabric layer, the recesses form a mixed bonded layer in which the nonwoven fabric and the heat-fusible resin material are mixed, and the amount of sinking of the surface of the nonwoven fabric layer in the recesses is 10 μm or more and is equal to or less than a thickness dimension of the heat-fusible resin layer.

[0007] According to the present invention, an excellent heater wire holding substrate can be provided. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 1A is a schematic plan view illustrating an outline of a configuration example of a sheet heater according to one embodiment. [Figure 1B] FIG. 1B is a schematic cross-sectional view showing an outline of a cross section of the sheet heater taken along line IB-IB shown in FIG. 1A. [Diagram 2] FIG. 2 is a schematic cross-sectional view illustrating an example of the configuration of the surface and vicinity of the heater wire holding substrate according to the first embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view illustrating an example of the configuration of the vicinity of the surface of the heater wire holding substrate according to the second embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an outline of a configuration example in the vicinity of the surface of a heater wire holding substrate according to a third embodiment. [Diagram 5] FIG. 5 is a schematic cross-sectional view illustrating an example of the configuration of the vicinity of the surface of a heater wire holding substrate according to a fourth embodiment. [Figure 6]FIG. 6 is a schematic cross-sectional view illustrating an example of the configuration of the vicinity of the surface of a heater wire holding substrate according to a fifth embodiment. [Figure 7] FIG. 7 is a flowchart showing an outline of an example of a method for manufacturing a heater wire holding substrate according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment will be described with reference to the drawings. The embodiment relates to a sheet heater that can be used, for example, as a seat heater. The sheet heater of the embodiment uses a cord-shaped heating element that has been reliable and cost-effective as a seat heater for many years. The cord-shaped heating element is provided on a heater wire holding substrate. The heater wire holding substrate of the embodiment is particularly configured to maximize the energy saving effect and various other effects.

[0010] Generally, nonwoven fabric is used for the heater wire holding substrate. Nonwoven fabric has various advantages such as suitability for sewing or bonding to hold the heater wire, excellent flex resistance, flame retardancy, and low cost. On the other hand, inexpensive and thin nonwoven fabric with a low basis weight has a low heat insulating effect, and a planar heater using such nonwoven fabric has a slow rise in temperature and a relatively low energy saving performance. The heater wire holding substrate of the present embodiment uses nonwoven fabric, and the disadvantages of the nonwoven fabric are overcome while maintaining the advantages of the nonwoven fabric.

[0011] [Configuration of sheet heater] Fig. 1A is a schematic plan view showing an outline of a configuration example of a sheet heater 1 according to this embodiment. Fig. 1B is a schematic cross-sectional view showing an outline of a cross section of the sheet heater 1 taken along line IB-IB shown in Fig. 1A.

[0012] The sheet heater 1 has a structure in which a cord-like heating element 5 is fixed on a heater wire holding substrate 10. The cord-like heating element 5 is fixed to the heater wire holding substrate 10 by sewing with an upper thread 6 and a lower thread 7. For example, the cord-like heating element 5 is laid on the surface of the heater wire holding substrate 10 according to a pattern program of an automatic sewing machine, and the cord-like heating element 5 is sewn and fixed to the heater wire holding substrate 10 by, for example, zigzag stitching with the upper thread 6 and the lower thread 7. The strength and looseness of the fixing of the cord-like heating element 5 can be adjusted by appropriately adjusting the sewing speed, stitch width, thread tension, etc. When the sheet heater 1 is used as a seat heater, downward deformation stress caused by a user sitting down can be alleviated by the slippage of the cord-like heating element 5. Such a structure provides high durability. The fixing of the cord-like heating element 5 to the heater wire holding substrate 10 is not limited to sewing, and may be, for example, fused using a heat-sealing resin or bonded using an adhesive.

[0013] [Composition of heater wire support substrate] Hereinafter, some configurations of the heater wire holding substrate 10 will be described.

[0014] First Embodiment A first embodiment of the heater wire holding substrate 10 will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view showing an outline of a configuration example near the surface of the heater wire holding substrate 11 according to this embodiment. The heater wire holding substrate 11 has a structure in which a heat-fusible resin layer 32 is provided on a nonwoven fabric layer 31.

[0015] The nonwoven fabric layer 31 has a basis weight of 80 g / m 2 More than 350g / m 2 It is preferable that the nonwoven fabric layer 31 is made of a nonwoven fabric material containing the following nonwoven fabric 21. The nonwoven fabric layer 31 has a basis weight of 100 g / m 2 More than 200g / m 2 It is more preferable that the nonwoven fabric 21 is made of a nonwoven material containing the following nonwoven fabric 21. The material of the nonwoven fabric 21 is, for example, a polyolefin resin. The basis weight of the nonwoven fabric 21 is 80 g / m 2If the thickness is less than 80 g / m, the nonwoven fabric 21 will be weak, and when the cord-shaped heating element 5 is fixed to the completed heater wire holding substrate 11, the heater wire holding substrate 11 may be distorted due to the rigidity of the cord-shaped heating element 5. 2 If the nonwoven fabric 21 has a basis weight of 350 g / m or less, the air permeability is good and the heat retention is poor, so that the energy saving performance may be poor. 2 If the amount is larger than this, when the completed heater wire holding substrate 11 is used, for example, as a seat heater, there is a risk that the human body will feel an undesirable stiffness when sitting in it. In addition, since the price of the nonwoven fabric 21 increases in direct proportion to the basis weight, a nonwoven fabric 21 with too high a basis weight is not economically preferable.

[0016] A heat-sealable resin material 22 formed by extruding a heat-sealable resin is placed on the nonwoven fabric material, and the heat-sealable resin material 22 is pressed and heat-sealed to the nonwoven fabric material over the entire surface thereof to form a heat-sealable resin layer 32. The heat-sealable resin is, for example, a polyolefin-based resin. The reason for selecting a polyolefin-based heat-sealable resin is that the material of a general nonwoven fabric is polyolefin-based, and that it is relatively inexpensive even when flame-retarded. As the polyolefin-based resin, a polyolefin resin or an olefin-based copolymer may be used alone or in combination of two or more kinds. As the polyolefin resin, for example, polyethylene, polypropylene, polybutene, etc. may be used. Polyethylene includes high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc. As the olefin-based copolymer, a copolymer of ethylene and any of propylene, vinyl acetate, acrylic acid, ethyl acrylate, vinyl chloride, etc., a copolymer of propylene and vinyl chloride, etc., or a modified product thereof may be used.

[0017] Of these, the polyolefin resin used in the present embodiment is preferably a polyolefin copolymer rather than polyethylene alone, since it is easy to impart flame retardancy and takes into consideration the melting point, heat fusion property, cost, and the like.

[0018] The heat-fusible resin material 22 used in the heat-fusible resin layer 32 can be formed, for example, by molding a commercially available polyolefin copolymer compound into a film shape using a biaxial stretching device.

[0019] The thickness of the heat-fusible resin layer 32, which substantially corresponds to the thickness of the heat-fusible resin material 22, is preferably, for example, 0.03 mm to 0.5 mm. The thickness of the heat-fusible resin layer 32 is more preferably, for example, 0.03 mm to 0.35 mm, and further preferably, for example, 0.05 mm to 0.15 mm.

[0020] The above-mentioned press heat fusion is performed by a hot press or the like equipped with an upper die having a plurality of protrusions. Since the upper die has a plurality of protrusions, this process is called debossing. As a result, a plurality of recesses 33 are formed on the surface of the heater wire holding substrate 11, in which the heat-fusible resin layer 32 penetrates the nonwoven fabric layer 31 in the depth direction. Here, in the recesses 33, the molten heat-fusible resin layer 32 penetrates not only the surface of the nonwoven fabric layer 31 but also in the depth direction of the recesses 33, and is fused to the nonwoven fabric layer 31 on the side of the recesses 33 and fixed to the nonwoven fabric layer 31. In this way, a mixed fixed layer 41 in which the nonwoven fabric layer 31 and the heat-fusible resin layer 32 are mixed is formed. The heat fusion may be performed by using a continuous heating roll device or the like.

[0021] In the recess 33, the nonwoven fabric layer 31 and the heat-sealable resin layer 32 are preferably as follows in the depth direction. That is, the recess 33 is formed by the heat-sealable resin layer 32 sinking further than the portion other than the recess 33. With this sinking of the heat-sealable resin layer 32, the nonwoven fabric layer 31 also sinks further than the portion other than the recess 33 in the recess 33. The sinking amount of the surface of the nonwoven fabric layer 31 in the recess 33, that is, the step between the surface position of the nonwoven fabric layer 31 in the portion other than the recess 33 and the surface position of the nonwoven fabric layer 31 in the recess 33, is preferably within a predetermined range. Specifically, the sinking amount of the nonwoven fabric layer 31 in the recess 33 is preferably 10 μm or more and less than the thickness dimension of the heat-sealable resin layer 32. It is more preferable that the sinking amount of the nonwoven fabric layer 31 in the recess 33 is 30 μm or more and less than 1 / 2 the thickness dimension of the heat-sealable resin layer 32.

[0022] If the amount of sinking of the surface of the nonwoven fabric layer 31 is less than 10 μm, the formation of the mixed fixed layer 41 is insufficient, and the effect of suppressing the occurrence of pinholes and wrinkles described below may not be sufficiently obtained. Also, if the amount of sinking of the surface of the nonwoven fabric layer 31 is greater than the thickness dimension of the heat-fusible resin layer 32, cracks are likely to occur at the ends of the recesses 33 of the heat-fusible resin layer 32 when the recesses 33 are formed. If cracks occur, the mechanical strength of the heater wire holding substrate 11 may decrease, and the effect of suppressing the occurrence of pinholes and wrinkles described below may not be sufficiently obtained.

[0023] The width of each recess 33 on the surface of the heat-sealable resin layer 32 is preferably, for example, 1 mm or more at its maximum portion. The width of each recess 33 on the surface of the heat-sealable resin layer 32 is more preferably, for example, 3 mm to 5 mm at its maximum portion. For example, when the shape of the recess 33 on the surface of the heat-sealable resin layer 32 is circular, the diameter is preferably 1 mm or more. For example, when the shape of the recess 33 on the surface of the heat-sealable resin layer 32 is circular, the diameter is more preferably 3 mm to 5 mm.

[0024] The shape of the protruding portion provided on the upper die of the hot press is preferably, for example, a cylindrical shape or a truncated cone shape. If the shape of the protruding portion is a prismatic column shape with corners, the heat-fusible resin layer 32 may be cracked by the protrusion being pushed in, so the shape of the protruding portion is preferably a shape without corners. In addition, since the molten resin of the heat-fusible resin material 22 is pushed into the soft and shapeless nonwoven fabric 21, in order to make the die removal smooth, the shape of the protruding portion is preferably a truncated cone shape with a slightly larger taper angle than a cylinder. The protrusion may be, for example, a truncated cone shape with a diameter of 5 mm at the lower base and a diameter of 3 mm at the upper base. The size of the protrusion is appropriately adjusted, for example, so that the size of the recess 33 formed in the heater wire holding substrate 11 is as described above.

[0025] The recesses 33 are preferably provided at a density of, for example, one or more recesses per 5 cm square.The recesses 33 are more preferably provided at a density of, for example, one or more recesses per 2 cm to 3 cm square.

[0026] <About the heater wire support substrate> One way to save energy in a seat heater is to shorten the time it takes for the heater to reach a specified set temperature when it is heated by the heater. The performance of the heater wire holding substrate contributes to this. Polyurethane foam with closed cell-like voids has good heat insulation properties and shortens the time it takes for the heater to heat up. However, polyurethane foam with flame-retardant specifications is very expensive. For this reason, it is not preferable as a heater wire holding substrate for a seat heater.

[0027] In contrast, thin nonwoven fabrics with low basis weight are relatively inexpensive even when flame-retardant, and are widely used. However, if a cord-shaped heating element is placed directly on a nonwoven fabric with a high porosity, the heat from the cord-shaped heating element is transferred to the nonwoven fabric by contact thermal conduction and convection, and the fibers of the nonwoven fabric act as heat dissipation fins. As a result, the start-up time of the heater becomes long and the energy efficiency is poor. For this reason, thin nonwoven fabrics with low basis weight are not suitable by themselves as a heater wire-holding substrate for seat heaters.

[0028] Therefore, it is possible to cover the surface of the nonwoven fabric with a heat-sealing film or the like. In this way, at least the heat loss due to convection is reduced, and the heat conduction in the surface direction by the film is improved, the rise time is shortened, and energy saving is improved. However, when a heat-sealing film is heat-sealed to a thin nonwoven fabric with a low basis weight, the following problems may occur. That is, since a generally inexpensive heat-sealing film is stretched and molded in the lengthwise and widthwise directions by a biaxial stretching machine, shrinkage occurs due to heating and cooling in the post-process. In addition, since the distribution of fiber density on the surface of the nonwoven fabric is random, the fusion density distribution with the heat-sealing film is also random, and the shrinkage distribution of the above-mentioned heat-sealing film is also random. As a result, shrinkage unevenness occurs in the heat-sealing film, pinholes and wrinkles are easily generated in the heat-sealing film, and distortion deformation is easily generated in the heater wire holding substrate as a whole.

[0029] Pinholes are likely to become the starting point of cracks in the heat-sealing film due to the stress of the heating and cooling cycles and the stress of repeated seating pressure when the sheet heater is in use. In addition, the occurrence of frequent pinholes increases convection in the nonwoven fabric, which may reduce the effectiveness of the heat-sealing film and reduce energy-saving performance. In addition, the distortion and deformation of the entire heater wire holding substrate can hinder accurate sewing operations when the cord-shaped heating element is fixed thereto by sewing, and is likely to cause poor needle insertion into the cord-shaped heating element. In addition, when the cord-shaped heating element is fixed thereto by adhesion, the degree of wrinkles and distortions that initially occurred in the heater wire holding substrate is further increased due to the rigidity of the cord-shaped heating element, which is likely to cause a deterioration in product yield.

[0030] In response to these problems, the heater wire holding substrate 11 according to the present embodiment has a recess 33 formed by debossing. As a result, the contraction force of the heat-sealing resin material 22, which occurs when the nonwoven fabric 21 and the heat-sealing resin material 22, such as a heat-sealing film, are thermally fused together is relaxed by the recess 33, and the effect of the heat shrinkage does not extend over a wide area. More specifically, by providing the recess 33, the heat-sealing resin material 22 melts and penetrates into the nonwoven fabric 21 not only on the surface of the nonwoven fabric 21 but also on the side of the recess 33, increasing the contact opportunity between the heat-sealing resin layer 32 and the nonwoven fabric layer 31, and the heat-sealing resin material 22 strongly embraces the nonwoven fabric 21 to form a mixed fixed layer 41. Therefore, the contraction force of the heat-sealing resin layer 32 is relaxed by the recess 33 and does not extend over a wide area. As a result, the number of pinholes and wrinkles that may occur in the heat-sealing resin layer 32 due to thermal shrinkage is reduced. Moreover, the heater wire holding substrate 11 as a whole is less likely to be distorted, and the heater wire holding substrate 11 having high flatness can be realized.

[0031] In addition, the heat-sealing resin layer 32 blocks the flow of air between the inside and outside of the nonwoven fabric layer 31, making it difficult for the heat from the cord-shaped heating element 5 to diffuse into the nonwoven fabric layer 31, which has many voids. In this way, the heater wire holding substrate 11 according to this embodiment functions as a heat insulating material. In addition, the heat from the cord-shaped heating element 5 is easily diffused in the planar direction by the heat-sealing resin layer 32, which is a continuous solid. As described above, these configurations realize a heater wire holding substrate 11 that is advantageous for energy saving, even though the base material is a thin nonwoven fabric 21 with a low basis weight. By using the heater wire holding substrate 11 that solves the above problems in a sheet heater 1 such as a sheet heater, the sheet heater 1 can achieve high energy saving performance.

[0032] The reason why the thickness of the heat-sealable resin layer 32 is preferably 0.03 mm to 0.5 mm as described above is that if the thickness of the heat-sealable resin layer 32 is thinner than 0.03 mm, there is a risk of many pinholes occurring due to the thermal contraction force during heat fusion, even if the recesses 33 are provided. Also, if the thickness of the heat-sealable resin layer 32 is thicker than 0.5 mm, there is a risk of distortion occurring in the nonwoven fabric layer 31, which may result in a poor yield in the production of the seat heater. Also, if the thickness of the heat-sealable resin layer 32 is thicker than 0.5 mm, the rise time during the temperature rise of the seat heater becomes longer and the overshoot becomes larger, which may increase power consumption and reduce the energy-saving performance.

[0033] Second Embodiment A second embodiment of the heater wire holding substrate 10 will be described with reference to Fig. 3. Here, differences from the first embodiment will be described, and the same parts will be denoted by the same reference numerals and their description will be omitted. Fig. 3 is a schematic cross-sectional view showing an outline of a configuration example near the surface of the heater wire holding substrate 12 according to this embodiment.

[0034] The heater wire holding substrate 12 of the present embodiment also has a structure in which a heat-fusible resin layer 32 is provided on a nonwoven fabric layer 31. Here, in the heater wire holding substrate 12 of the present embodiment, the nonwoven fabric structure constituting the nonwoven fabric layer 31 is a nonwoven fabric structure in which aluminum fine particles 26 are attached to the surface of the nonwoven fabric 21.

[0035] The aluminum particles 26 can be attached to the surface of the nonwoven fabric 21 by, for example, vapor deposition, such as vacuum deposition, sputtering, plasma spraying, etc. Vacuum deposition deposits aluminum at the atomic level, so the aluminum deposition layer formed is dense, which is preferable in terms of thermal conduction. Sputtering and plasma spraying have a high deposition rate, but the aluminum deposition layer formed is a deposition of granular matter, albeit very fine, and contains voids, even if they are very fine. In the vapor deposition method, the amount of aluminum particles 26 decreases with the depth of the nonwoven fabric 21. Furthermore, the aluminum particles 26 are not attached to the surface that is shaded from the aluminum evaporation source.

[0036] The aluminum particles 26 may be attached to the surface of the nonwoven fabric 21 by, for example, mixing the aluminum particles 26 into a liquid adhesive, spraying it onto the surface of the nonwoven fabric 21, and drying to adhere the particles. The nonwoven fabric structure containing the aluminum particles 26 may also be produced by collecting scraps of long fibers that have been previously coated with aluminum, and using the scraps to form a nonwoven fabric.

[0037] The thickness of the aluminum deposition layer is, for example, 3 μm to 50 μm, preferably 5 μm to 15 μm. If the thickness of the aluminum deposition layer is 3 μm or less, the thermal conductivity of aluminum decreases. If the thickness of the aluminum deposition layer is 50 μm or more, the aluminum deposition layer becomes easily peeled off. Furthermore, if the thickness of the aluminum deposition layer is 50 μm or more, the production volume per hour decreases in the production of the nonwoven fabric structure, and the cost increases.

[0038] In this embodiment as well, the heat fusion may be performed with debossing using a hot press or the like equipped with an upper die having a plurality of protrusions. In the heater wire holding substrate 12 of this embodiment, the mixed fixing layer 42 formed by the recess 33 includes a nonwoven fabric layer 31 containing the nonwoven fabric 21 and aluminum particles 26 and a heat fusible resin layer 32 mixed therein. That is, the mixed fixing layer 42 includes a mixture of the nonwoven fabric 21, aluminum particles 26, and heat fusible resin material 22. In this embodiment as well, the sinking amount of the recess 33 on the surface of the nonwoven fabric layer 31 containing the nonwoven fabric 21 and aluminum particles 26 is preferably 10 μm or more and equal to or less than the thickness of the heat fusible resin layer 32.

[0039] According to the heater wire holding substrate 12 of the present embodiment, the heat from the cord-like heating element 5 is more easily diffused in the planar direction due to the aluminum fine particles 26 in the mixed fixed layer 42 than in the heater wire holding substrate 11 of the first embodiment. As a result, even if the heater wire holding substrate 12 uses the thin nonwoven fabric 21 with a low basis weight as the base material, the planar heater 1 manufactured using the heater wire holding substrate 12 has a short warm-up time and high energy-saving performance.

[0040] As in the present embodiment, when a nonwoven fabric material having aluminum particles attached to the surface of a thin nonwoven fabric with a low basis weight is heat-fused to a heat-fusible resin material by hot pressing or the like, the same problems as those described above may generally occur. That is, during the heating and cooling process, the heat-fusible resin material shrinks unevenly due to differences in contact density with the nonwoven fabric material, etc., which makes it easy for pinholes and wrinkles to form in the heat-fusible resin layer. In addition, the heater wire holding substrate as a whole is prone to distortion and deformation. At this time, inside the nonwoven fabric material, the tip region of the nonwoven fabric to which the aluminum particles are attached is pulled into an indefinite shape, making it easy for the aluminum particles to be unevenly distributed. In this case, there is a risk that the thermal conductivity in the planar direction will become uneven. In such a state, as a planar heater, there is a risk that it will cause uneven heating and induce local heating.

[0041] In contrast, in the heater wire holding substrate 12 according to the present embodiment, the recesses 33 are formed by debossing. As a result, the contraction force of the heat-fusible resin material 22 generated when the nonwoven fabric material containing the nonwoven fabric 21 and the aluminum fine particles 26 and the heat-fusible resin material 22 are heat-fused is mitigated by the recesses 33, and the influence of the heat shrinkage does not extend over a wide area. As a result, the number of pinholes and wrinkles that may occur in the heat-fusible resin layer 32 due to heat shrinkage is reduced. In addition, the heater wire holding substrate 12 as a whole is less likely to be distorted, and a heater wire holding substrate 12 with high flatness is realized. In addition, a heater wire holding substrate 12 without the risk of localized heating such as uneven heating is realized.

[0042] Third embodiment A third embodiment of the heater wire holding substrate 10 will be described with reference to Fig. 4. Here, differences from the second embodiment will be described, and the same parts will be denoted by the same reference numerals and description thereof will be omitted. Fig. 4 is a schematic cross-sectional view showing an outline of a configuration example near the surface of the heater wire holding substrate 13 according to this embodiment.

[0043] The heater wire holding substrate 13 of this embodiment also has a structure in which a heat-fusible resin layer 32 is provided on a nonwoven fabric layer 31. As in the second embodiment, the nonwoven fabric structure constituting the nonwoven fabric layer 31 is formed by adhering aluminum fine particles 26 to the surface of the nonwoven fabric 21. In the heater wire holding substrate 13 of this embodiment, the heat-fusible resin structure constituting the heat-fusible resin layer 32 is formed by dispersing fine particles of a high thermal conductivity material in a heat-fusible resin.

[0044] The fine particles of the high thermal conductivity material may be, for example, fine metal particles such as aluminum, copper, etc. The fine particles of the high thermal conductivity material may be, for example, fine ceramic particles such as alumina, magnesia, etc. The fine particles of the high thermal conductivity material may be, for example, fine graphite particles, etc. The fine particles of the high thermal conductivity material may be, for example, fine silicon carbide particles, etc. That is, for example, the heat-fusible resin structure constituting the heat-fusible resin layer 32 may be a heat-fusible resin having at least one fine particle of aluminum, copper, alumina, magnesia, graphite, etc. dispersed therein.

[0045] In the heater wire holding substrate 13 of the present embodiment, the heat fusible resin layer 32 is formed by the heat fusible resin material 23 including a heat fusible resin structure in which fine particles of a high thermal conductivity material are dispersed. The heat fusible resin material 23 in which fine particles of a high thermal conductivity material are dispersed of the present embodiment has superior thermal conductivity compared to the heat fusible resin material 22 in the second embodiment which is made only of a heat fusible resin. Therefore, the heat fusible resin layer 32 of the heater wire holding substrate 13 of the present embodiment formed by the heat fusible resin material 23 in which fine particles of a high thermal conductivity material are dispersed easily diffuses heat from the cord-shaped heating element 5 in the planar direction.

[0046] Metallic particles such as aluminum and copper have high thermal conductivity. On the other hand, if they are added in a slightly larger amount, the thermally adhesive resin material 23 becomes hard, and cracks are likely to occur in the thermally adhesive resin layer 32 during debossing. For this reason, metallic particles such as aluminum and copper cannot be added in large amounts, and it is not easy to significantly increase the thermal conductivity of the thermally adhesive resin layer 32 by using them. Also, ceramic particles such as alumina and magnesia can be added in a slightly larger amount than the above-mentioned metallic particles. On the other hand, they have a relatively low thermal conductivity, and it is not easy to significantly increase the thermal conductivity of the thermally adhesive resin layer 32 by using them. Graphite such as scaly graphite has a relatively high thermal conductivity, second only to metal materials. Furthermore, graphite has high lubricity. For this reason, even if a large amount of graphite is added, the thermally adhesive resin material 23 does not become very hard. For these reasons, graphite is particularly suitable as a material to be added to the thermally adhesive resin material 23.

[0047] Increasing the thermal conductivity of the heat-fusible resin layer 32 in the planar direction by using fine particles of a highly thermally conductive material can help to compensate for the non-uniform thermal conduction of the aluminum fine particles 26 adhered to the nonwoven fabric 21. Depending on the conditions, forming the heat-fusible resin layer 32 to which fine particles of a highly thermally conductive material have been added can also eliminate the need for the aluminum fine particles 26 to adhere to the nonwoven fabric 21.

[0048] Furthermore, when graphite such as scaly graphite is selected from among the high thermal conductivity materials, the heat-fusible resin layer 32 can impart a far-infrared radiation function to the sheet heater 1 in addition to the above-mentioned advantages. This far-infrared radiation function enables, for example, the seat heater to heat the human body not only by contact thermal conduction but also by heat rays called far-infrared rays. As a result, by using the heater wire holding substrate 13 in which graphite is added to the heat-fusible resin layer 32, an energy-saving effect can be obtained in that the sensible temperature can be maintained even if the power applied to the seat heater is reduced.

[0049] In this embodiment, the heat fusion may be performed with debossing using a hot press or the like equipped with an upper die having a plurality of protrusions. In the heater wire holding substrate 13 of this embodiment, the mixed fixing layer 43 formed by the recess 33 is a mixture of the nonwoven fabric layer 31 containing the nonwoven fabric 21 and the aluminum particles 26, and the heat fusion resin layer 32 formed of a heat fusion resin structure in which the particles of a high thermal conductivity material are dispersed in the heat fusion resin. That is, in the mixed fixing layer 43, the nonwoven fabric 21, the aluminum particles 26, the particles of a high thermal conductivity material, and the heat fusion resin material are mixed.

[0050] As in the present embodiment, when a nonwoven fabric material in which aluminum particles are attached to the surface of a thin nonwoven fabric with a low basis weight is heat-fused to a heat-fusible resin material containing graphite or the like by hot pressing or the like, the same problems as those described above may occur. That is, in general, during the heating and cooling process, the heat-fusible resin material shrinks unevenly due to differences in contact density with the nonwoven fabric material, etc., which makes it easy for pinholes and wrinkles to form in the heat-fusible resin layer. In addition, the heater wire holding substrate as a whole is also prone to distortion deformation. At this time, aluminum particles are unevenly distributed inside the nonwoven fabric material, which may cause uneven thermal conductivity in the planar direction. In such a state, as a planar heater, it may cause uneven heating, and the heat-fusible resin layer containing graphite or the like may further strengthen the uneven heating, inducing local heating.

[0051] In contrast, in the heater wire holding substrate 13 according to this embodiment, the recesses 33 are formed by debossing. As a result, the contraction force of the heat-fusible resin material 23 generated when the nonwoven fabric material and the heat-fusible resin material 23 are heat-fused is alleviated by the recesses 33. As a result, the number of pinholes and wrinkles that may occur in the heat-fusible resin layer 32 due to thermal shrinkage is reduced. In addition, the heater wire holding substrate 13 as a whole is less likely to be distorted, and a heater wire holding substrate 13 with high flatness is realized. In addition, a heater wire holding substrate 13 that is free from the risk of localized heating such as uneven heating is realized.

[0052] Fourth embodiment A fourth embodiment of the heater wire holding substrate 10 will be described with reference to Fig. 5. Here, differences from the third embodiment will be described, and the same parts will be denoted by the same reference numerals and their description will be omitted. Fig. 5 is a schematic cross-sectional view showing an outline of a configuration example near the surface of the heater wire holding substrate 14 according to this embodiment.

[0053] The heater wire holding substrate 14 of this embodiment also has a structure in which a heat-sealable resin layer 32 is provided on a nonwoven fabric layer 31. As in the third embodiment, the nonwoven fabric structure constituting the nonwoven fabric layer 31 is a structure in which aluminum particles 26 are attached to the surface of a nonwoven fabric 21. In the heater wire holding substrate 14 of this embodiment, the heat-sealable resin layer 32 is a structure in which a heat-sealable resin material 23 formed of a heat-sealable resin structure in which particles of a high thermal conductivity material are dispersed in a heat-sealable resin, and a heat-sealable resin material 22 formed of a heat-sealable resin are laminated. The heat-sealable resin material 23 formed of a heat-sealable resin structure in which particles of a high thermal conductivity material are dispersed in a heat-sealable resin is similar to the heat-sealable resin material 23 constituting the heat-sealable resin layer 32 of the third embodiment. The heat-fusible resin material 22 formed from the heat-fusible resin is similar to the heat-fusible resin material 22 constituting the heat-fusible resin layer 32 in the second embodiment.

[0054] For example, the heater wire holding substrate 14 is formed by heat fusing a nonwoven fabric material with a heat-fusible resin material 22 formed from a heat-fusible resin, and then heat fusing a heat-fusible resin material 23 formed from a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin. Even if a pinhole is generated due to uneven shrinkage of the heat-fusible resin material 22 when the nonwoven fabric material and the heat-fusible resin material 22 formed from a heat-fusible resin are heat-fusible, the pinhole can be repaired by further heat fusing the heat-fusible resin material 23 formed from a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin.

[0055] In this embodiment, the thermal fusion may be performed with debossing by a hot press or the like equipped with an upper die having a plurality of protrusions. Note that hot pressing or the like with debossing may be performed in both the thermal fusion of the thermally adhesive resin material 22 formed of a thermally adhesive resin and the thermal fusion of the thermally adhesive resin material 23 formed of a thermally adhesive resin structure in which fine particles of a high thermal conductivity material are dispersed in the thermally adhesive resin. In addition, in the thermal fusion of the thermally adhesive resin material 22 formed of a thermally adhesive resin, hot pressing or the like with debossing may be performed, and in the thermal fusion of the thermally adhesive resin material 23 formed of a thermally adhesive resin structure in which fine particles of a high thermal conductivity material are dispersed in the thermally adhesive resin, hot pressing or the like without debossing may be performed.

[0056] In the heater wire holding substrate 14 of this embodiment, the mixed fixed layer 44 formed by the recess 33 is a mixture of the nonwoven fabric layer 31 containing the nonwoven fabric 21 and the aluminum particles 26, and the heat-fusible resin layer 32 formed of the heat-fusible resin material 22 and the heat-fusible resin structure in which the particles of a high thermal conductivity material are dispersed in the heat-fusible resin. That is, in the mixed fixed layer 43, the nonwoven fabric 21, the aluminum particles 26, the particles of a high thermal conductivity material, and the heat-fusible resin material are mixed.

[0057] The vertical positional relationship between the heat-fusible resin material 22 formed from the heat-fusible resin and the heat-fusible resin material 23 formed from the heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin may be changed as appropriate. For example, since the thermal conductivity in the planar direction differs depending on whether only the nonwoven fabric 21 is used as the nonwoven fabric material or whether the nonwoven fabric 21 to which aluminum fine particles 26 are attached is used, the vertical positional relationship between the heat-fusible resin material 22 formed from the heat-fusible resin and the heat-fusible resin material 23 formed from the heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin may be changed depending on the structure.

[0058] Furthermore, the configuration of the sheet heater 1 is not limited to the configuration in which the cord-like heating element 5 is disposed on the heat-fusible resin layer 32 in which the heat-fusible resin material 22 formed of heat-fusible resin and the heat-fusible resin material 23 formed of a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin are laminated. For example, the cord-like heating element 5 may be disposed between the heat-fusible resin material 22 formed of heat-fusible resin and the heat-fusible resin material 23 formed of a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin. Fixing of the cord-like heating element 5 is not limited to sewing, and may be performed by, for example, heat fusion. When a cord-shaped heating element 5 is arranged between a heat-fusible resin material 22 formed from a heat-fusible resin and a heat-fusible resin material 23 formed from a heat-fusible resin structure in which fine particles of high thermal conductivity material are dispersed in a heat-fusible resin, high thermal conductivity in the planar direction is obtained, thereby improving the energy-saving performance of the planar heater 1 in particular.

[0059] Laminating the heat-fusible resin material 22 made of a heat-fusible resin and the heat-fusible resin material 23 made of a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in the heat-fusible resin may increase costs. However, while obtaining all the advantages of the first to third embodiments, it is possible to significantly suppress heat loss due to convection in the nonwoven fabric layer 31 by sealing pinholes that may occur. As a result, a heater wire holding substrate 14 that contributes to energy saving is realized.

[0060] Fifth embodiment A fifth embodiment of the heater wire holding substrate 10 will be described with reference to Fig. 6. Here, differences from the first embodiment will be described, and the same parts will be denoted by the same reference numerals and their description will be omitted. Fig. 6 is a schematic cross-sectional view showing an outline of a configuration example near the surface of a heater wire holding substrate 15 according to this embodiment.

[0061] The heater wire holding substrate 15 of this embodiment also has a structure in which a heat-fusible resin layer 32 is provided on a nonwoven fabric layer 31. Here, in the heater wire holding substrate 15 of this embodiment, a heat-fusible resin material that has been heat-treated in advance to shrink and have wrinkles is used as the heat-fusible resin material 24 that forms the heat-fusible resin layer 32. The heat-fusible resin material 24 is, for example, a heat-fusible resin material formed into a film shape at a high temperature of, for example, 220°C by a biaxial stretching device, heated by a heat roller or a hot air furnace at a lower temperature, for example, 180°C, and wound up in a slowly cooling environment without applying much tension, so as to be appropriately shrunk.

[0062] In this embodiment as well, the heat fusion may be performed with debossing using a hot press or the like equipped with an upper die having a plurality of protrusions. In the heater wire holding substrate 15 of this embodiment, the mixed fixing layer 45 formed by the recess 33 includes a mixed nonwoven fabric layer 31 and a mixed heat fusible resin layer 32, and a mixed nonwoven fabric 21 and a mixed heat fusible resin material 24.

[0063] In the heater wire holding base material 15 of the present embodiment, since the heat-fusible resin material 24 has been shrunk in advance, it is possible to suppress the occurrence of pinholes and wrinkles during heat fusion to the nonwoven fabric 21, and also to suppress distortion of the entire heater wire holding base material 15. That is, it is possible to achieve ease of processing and high cost-effectiveness while obtaining all the advantages of the first to third embodiments.

[0064] The previously shrinking of the thermally adhesive resin material may be used not only in combination with the first embodiment as in this embodiment, but also in combination with the second to fourth embodiments.

[0065] [Method of manufacturing heater wire holding substrate] 7 shows an outline of an example of a method for manufacturing the heater wire-holding substrate 10. As described above, in manufacturing the heater wire-holding substrate 10, a nonwoven fabric material is prepared (step S1), and a fusible resin material is also prepared (step S2). The fusible resin material is placed on the nonwoven fabric material, and a pressure heat fusion process accompanied by debossing is performed (step S3), thereby completing the heater wire-holding substrate 10. EXAMPLES

[0066] Examples of the heater wire holding substrates according to the above-mentioned five embodiments and examples of seat heaters using them will be described below.

[0067] [Preparation of heater wire support substrate] <Nonwoven fabric> As a nonwoven fabric, it meets the flame retardant standard of FMVSS302 and has a basis weight of approximately 150g / m 2 The material used was 1.5 mm thick and had a tensile strength of 80 N or more in both the vertical and horizontal directions.

[0068] In the case of attaching aluminum particles to the nonwoven fabric, the nonwoven fabric material was prepared as follows. That is, the attachment of aluminum particles to the nonwoven fabric was performed by vacuum deposition. The degree of vacuum in the vacuum deposition was about 10 -6 The thickness of the aluminum layer on the surface of the nonwoven fabric was approximately 10 μm, and the thickness of the aluminum layer became approximately zero at a depth of approximately 50 μm into the nonwoven fabric.

[0069] <Heat-fusible resin material> As the heat-sealable resin, a commercially available flame-retardant polyolefin resin compound QU1548A1 (manufactured by Mitsubishi Chemical Corporation) was used. This resin was used to produce a heat-sealable resin material with a thickness of 0.1 mm using a biaxially stretched film manufacturing device consisting of a single-screw extruder.

[0070] The heat-sealable resin material having fine particles of a highly thermally conductive material dispersed therein was prepared as follows. That is, scaly graphite MCP-10 (manufactured by Nippon Graphite Industries Co., Ltd.) was used as the fine particles of the highly thermally conductive material. 10 parts by weight of scaly graphite was added to 100 parts by weight of the above-mentioned flame-retardant polyolefin resin compound. This mixture was thoroughly stirred in a kneader. Then, a biaxially stretched film manufacturing device having a single-axis extruder was used to prepare a heat-sealable resin material having a thickness of 0.1 mm having fine particles of a highly thermally conductive material dispersed therein, i.e., a black heat-sealable resin material having high thermal conductivity. The average surface resistance of this black heat-sealable resin material having high thermal conductivity was approximately 10 8 Ω / cm 2It was.

[0071] <Heat fusion> The nonwoven fabric material and the heat-fusible resin material were thermally fused using a hot press equipped with an upper die with multiple protrusions. The protrusions were truncated cone-shaped protrusions with a diameter of 5 mm at the bottom and 3 mm at the top, and a height of 50 μm. The density of the protrusions was one protrusion per 3 cm square.

[0072] Example 1 As Example 1, the heater wire holding substrate 11 according to the first embodiment described with reference to FIG. 2 was produced. A heat-fusible resin material 22 not containing dispersed fine particles of a high thermal conductivity material was placed on a nonwoven fabric 21 on which fine aluminum particles were not vacuum-deposited, and these were heat-fused together by a hot press equipped with an upper die having a plurality of protrusions. The heating temperature by the hot press was 180° C., and the heating time was 10 seconds. This heat fusion formed a mixed fixed layer 41 in which the nonwoven fabric 21 and the heat-fusible resin material 22 were mixed together.

[0073] Example 2 As Example 2, the heater wire holding substrate 12 according to the second embodiment described with reference to FIG. 3 was produced. A heat-fusible resin material 22 in which fine particles of a high thermal conductivity material were not dispersed was placed on a nonwoven fabric material in which fine aluminum particles 26 were vacuum-deposited on a nonwoven fabric 21, and these were heat-fused together by a hot press equipped with an upper die having a plurality of protrusions. The heating temperature by the hot press was 180° C., and the heating time was 10 seconds. This heat fusion formed a mixed fixed layer 42 in which the nonwoven fabric 21, the fine aluminum particles 26, and the heat-fusible resin material 22 were mixed together.

[0074] Example 3 As Example 3, the heater wire holding substrate 13 according to the third embodiment described with reference to FIG. 4 was produced. A heat-fusible resin material 23 having fine particles of a high thermal conductivity material dispersed therein was placed on a nonwoven fabric material having aluminum fine particles 26 vacuum-deposited on a nonwoven fabric 21, and these were heat-fused together by a hot press equipped with an upper die having a plurality of protrusions. The heating temperature by the hot press was 180° C., and the heating time was 20 seconds. This heat fusion formed a mixed fixed layer 43 in which the nonwoven fabric 21, the aluminum fine particles 26, and the heat-fusible resin material 23 having fine particles of a high thermal conductivity material dispersed therein were mixed together.

[0075] Example 4 As Example 4, the heater wire holding substrate 14 according to the fourth embodiment described with reference to FIG. 5 was produced. A heat-sealable resin material 22 in which fine particles of a high thermal conductivity material are not dispersed was placed on a nonwoven fabric material in which fine particles of aluminum 26 were vacuum-deposited on a nonwoven fabric 21, and these were heat-sealed by a hot press equipped with an upper die having a plurality of protrusions. The heating temperature by the hot press was 180° C., and the heating time was 10 seconds. Next, a heat-sealable resin material 23 in which fine particles of a high thermal conductivity material are dispersed was placed on top of this, and these were heat-sealed by a hot press equipped with an upper die having a plurality of protrusions. The heating temperature by the hot press was 180° C., and the heating time was 20 seconds. By these heat fusions, a mixed fixed layer 44 was formed in which the nonwoven fabric 21, the fine particles of aluminum 26, the heat-sealable resin material 22 in which fine particles of a high thermal conductivity material are not dispersed, and the heat-sealable resin material 23 in which fine particles of a high thermal conductivity material are dispersed were mixed.

[0076] Example 5 As Example 5, the heater wire holding substrate 15 according to the fifth embodiment described with reference to FIG. 6 was produced. The heat-fusible resin material 22, in which fine particles of a high thermal conductivity material were not dispersed, was pressed and heated by a flat hot press, and then slowly cooled. The heating temperature by the hot press was 180° C., and the heating time was 10 seconds. In this manner, the heat-fusible resin material 24 in a state in which it had shrunk and small wrinkles were scattered was prepared.

[0077] The heat-fusible resin material 24, which had small wrinkles scattered thereon due to the shrinkage described above, was placed on the nonwoven fabric 21 on which the aluminum particles were not vacuum-deposited, and the two were heat-fused together using a hot press equipped with an upper die having multiple protrusions. The heating temperature in the hot press was 180°C, and the heating time was 10 seconds. This heat fusion formed a mixed fixed layer 45 in which the nonwoven fabric 21 and the heat-fusible resin material 24 were mixed together.

[0078] Comparative Example 1 As Comparative Example 1, a sample was produced by placing a heat-fusible resin material 22 without dispersed fine particles of a high thermal conductivity material on a nonwoven fabric material in which aluminum fine particles 26 were vacuum-deposited on a nonwoven fabric 21, and heat-fusing them together using a hot press equipped with a flat upper die without protrusions. The heating temperature in the hot press was 180°C, and the heating time was 10 seconds. That is, a heater wire holding substrate having the same layer structure as in Example 2 but without recesses 33 was produced.

[0079] Comparative Example 2 As Comparative Example 2, a sample consisting of only the nonwoven fabric 21 on which no fine aluminum particles were vacuum-deposited was prepared as the heater wire-holding substrate.

[0080] <sample> Table 1 shows the configurations of the samples according to the examples and comparative examples prepared as described above.

[0081] [Table 1]

[0082] [Fabrication of a sheet heater] A sheet heater was produced using the heater wire holding substrates according to the above-mentioned respective Examples and Comparative Examples. That is, as shown in FIG. 1, a sheet heater 1 was produced in which a cord-shaped heating element 5 was fixed onto each heater wire holding substrate 10.

[0083] <Code-shaped heating element> The cord-like heating element 5 was as follows. The winding core was made of fully aromatic polyester fibers bundled together to have an outer diameter of 0.25 mm. The resistance wire was made of a φ0.075 mm copper-tin 3% alloy wire. Three resistance wires were twisted together to make a twisted wire, and six of these twisted wires were aligned and wound transversely around the winding core at a pitch of 1.815 mm. An insulating coating layer of ETFE resin was extrusion-coated on top of the twisted wire to a thickness of 0.2 mm, producing a cord-like heating element 5 with an outer diameter of 0.9 mm.

[0084] In all of Examples 1 to 5 and Comparative Examples 1 and 2, the length of the cord-shaped heating element was 5.75±0.06 m, and the resistance value was 1.9±0.02Ω.

[0085] <Fixing cord-shaped heating element> For all of the heater wire-holding substrates 10 in Examples 1 to 5 and Comparative Examples 1 and 2, an automatic sewing machine was used to follow a meandering pattern program to lay the cord-like heating element 5 on the heater wire-holding substrate 10, and at the same time, the heater wire-holding substrate 10 was sewn and fixed with an upper thread 6 and a lower thread 7 to produce a sheet heater 1.

[0086] In addition, as the planar heater 1 corresponding to Example 4, a cord-shaped heating element 5 was sewn and fixed to the surface of the heater wire holding substrate 12 of Example 2, and a heat-fusible resin material 23 having fine particles of a high thermal conductivity material dispersed therein was placed on top of that, and the planar heater 1 was produced by heat-fusible bonding these together using a hot press equipped with an upper mold without protrusions, and used in the following experiments.

[0087] [Methods of measurement] <Measuring the shape of the heater wire support substrate> In the measurement of the heater wire holding substrates according to Examples 1 to 5 and Comparative Example 1, they were cut into 30 cm squares to prepare samples. The cross sections of the heater wire holding substrates according to Examples 1 to 5 were observed under a microscope, and the depth of the recesses 33 was measured. Note that since nonwoven fabrics have a structure in which fibers are irregularly scattered, the measured depth is an average approximate value. In addition, a central 10 cm square of each sample was observed under a microscope, and the number of pinholes was counted. In addition, the maximum distortion dimension from the plane of each sample was measured.

[0088] <Measurement of temperature characteristics of a sheet heater> The sheet heater samples according to Examples 1 to 5 and Comparative Examples 1 and 2 were placed on an insulating elastic sheet for automobiles without being adhered to it, and the temperature characteristics of the surface of the sheet heater were directly measured without covering it with the sheet skin. The measurements were performed in a windless environment at room temperature of 25°C.

[0089] Three thermocouples were used for the measurements. The thermocouples were placed in positions that did not contact the cord-shaped heating element, at the center of the sheet heater and about 5 cm to the left and right. The tips of each thermocouple were fixed to the sheet heater with adhesive. The three thermocouples were connected to a general-purpose temperature logger, and the temperature change was recorded every second, and the average of the three values ​​was taken as the measurement value. The reason for measuring the sheet heater in this way under environmental conditions close to that of a single unit was to clarify the essential performance differences between each sample.

[0090] In addition, a temperature control thermocouple was attached to the center of the sheet heater, adjacent to the measurement thermocouple. The temperature control thermocouple was positioned so that it did not come into contact with the cord-shaped heating element. The temperature control thermocouple was connected to a temperature controller. Since the resistance of the cord-shaped heating element is temperature dependent, the applied voltage (approximately 12.5 V) was fine-tuned for each sample while watching the power meter in advance so that the power consumption at 40°C would be 82.1 W.

[0091] To measure the rise time, the sheet heater was connected directly to a DC power supply without going through a temperature controller. When the power supply was switched on, the temperature measured using three thermocouples rose. The measured value was the average of the three temperatures recorded by the temperature logger. For each sample, the rise time was measured as the time from when the power supply was switched on until the surface temperature of the sheet heater reached 40°C.

[0092] To measure power consumption, the sheet heater was connected to a DC power source via an ON-OFF type temperature controller. The temperature controller was set to an OFF point of 40°C, an ON point of 39.5°C, and a hysteresis width of 0.5°C. The switch was turned ON to set the temperature to automatic temperature control, and the power consumption was measured using an integrated wattmeter. The average value of the integrated power for 30 minutes from the moment the power switch was turned ON was determined as the average power consumption.

[0093] <Measurement of far-infrared radiation from a sheet heater> The sheet heater was hung in the air at 25°C in a windless environment and connected to a DC power source via a temperature controller. The temperature controller was set to 40°C and put into automatic temperature control mode. A black cloth large enough to hide the sheet heater was stretched in the air 15cm away from the surface of the seat heater. The surface temperature of the black cloth, which corresponds to the center of the sheet heater, was measured using a far-infrared thermograph. Measurements were taken at 1-minute intervals for 10 minutes, and the average temperature was determined as the far-infrared heating.

[0094] <Measurement of durability against seating stress of sheet heater> A sheet heater was sandwiched between an automotive heat insulating elastic sheet and a skin cover. A DC power source was connected to the sheet heater, and 13.5V DC was applied. Sitting stress was simulated using an anthropomorphic robot. One cycle consisted of rotating and sliding the seat to get in and sit on it, applying a load of 40kg, and vibrating up and down 20 times, followed by the reverse motion to get out and get off. This cycle was repeated 10,000 times in a test. After this test, it was visually checked whether minute pieces of evaporated aluminum, which were generated by the destruction of the heater wire holding substrate, had come out of the heat fusible resin layer 32, and whether minute pieces containing graphite had been scattered by the destruction of the heat fusible resin layer 32.

[0095] <Measurement of Antistatic Ability> A sheet heater was placed between an automotive heat insulating / elastic sheet and a skin cover. A DC power source was connected to the sheet heater, and the switch was turned off to de-energize it. The surface of the skin cover was rubbed strongly with a polyester cloth 10 times over an area of ​​approximately 30 cm square, and then the electrostatic charge was immediately measured at a distance of 25 mm using a static electricity tester.

[0096] [Results and evaluation of various measurements] <Shape of heater wire holding substrate> The measurement results of the depth of the recess 33, the number of pinholes, and the size of the distortion are shown in Table 2.

[0097] [Table 2]

[0098] It was confirmed that the heater wire holding substrates according to Examples 1 to 5 manufactured by a hot press equipped with an upper die having a protrusion with a height of 50 μm had recesses 33 formed with a depth roughly corresponding to the protrusion of the upper die. The nonwoven fabric layer 31 sank 10 μm or more into the recesses 33. It was confirmed that the heat-sealable resin layer 32 was sufficiently embedded in the nonwoven fabric layer 31 in the depth direction, and a mixed fixed layer was formed in which the nonwoven fabric, aluminum particles, high thermal conductivity material particles, heat-sealable resin material, etc. were mixed.

[0099] Regarding the number of pinholes, a very large number of pinholes were confirmed in the heater wire holding substrate of Comparative Example 1, which was not provided with recesses. In contrast, it was confirmed that the occurrence of pinholes was suppressed in the heater wire holding substrates of Examples 1 to 5, which were provided with the recesses 33. This indicates that the contraction force generated in the heat-fusible resin layer 32 during heat fusion is stopped by the recesses 33, and the expansion of the contraction force over a wide range is mitigated.

[0100] The distortion dimensions of the heater wire holding substrates were as follows. The distortion of the heater wire holding substrates was most significant at the four corners of each substrate. The heater wire holding substrate of Comparative Example 1, which had no recesses, had a very large distortion. The distortion was so large that the cord-shaped heating element 5 could not be sewn with an automatic sewing machine, and the cord-shaped heating element 5 had to be sewn while manually operating the automatic sewing machine, making it difficult to sew the cord-shaped heating element 5 with high accuracy. In contrast, the heater wire holding substrates of Examples 1 to 5, which had recesses 33, had a small distortion. The distortion was so large that the cord-shaped heating element 5 could be sewn with an automatic sewing machine.

[0101] <Characteristics of Planar Heater> The measurement results of various properties are shown in Table 3.

[0102] [Table 3]

[0103] The results of the rise time are as follows. In Comparative Example 2, which does not have a heat-sealable resin layer, the rise time was very long. In contrast, in Examples 2 to 4, which have a heat-sealable resin layer 32 and a nonwoven fabric layer 31 containing aluminum fine particles 26, the rise time was significantly shorter. It was confirmed that the aluminum fine particles 26 contained in the nonwoven fabric layer 31 are effective in shortening the rise time. In addition, in Examples 1 and 5, which do not contain aluminum fine particles 26 in the nonwoven fabric layer 31 but have a heat-sealable resin layer 32, the rise time was shorter than that of Comparative Example 2. From these results, it was confirmed that the heat-sealable resin layer 32 is effective in shortening the rise time. This is thought to be because the heat-sealable resin layer 32 blocks the air flowing through the nonwoven fabric 21, and the nonwoven fabric 21 acts as a heat insulating material. As described above, it was confirmed that the rise time was shortened in Examples 1 to 5, and an energy-saving effect was obtained. In Comparative Example 1, the effect of shortening the rise time commensurate with the material and structure was not obtained. This was thought to be due to the fact that the sewing of the cord-like heating element 5 had to be done semi-manually.

[0104] As for the average power consumption, a similar tendency was observed in the rise time in Examples 1 to 5 and Comparative Examples 1 and 2, and it was confirmed that an energy saving effect was obtained in Examples 1 to 5.

[0105] <Far-infrared radiation from a sheet heater> According to the results of the far-infrared heating measurement, in the case of Examples 3 and 4 having the heat-fusible resin material 23 with fine particles of a highly thermally conductive material dispersed therein, a surface temperature rise of about 4°C to 5°C was observed in the black cloth for measurement. This temperature rise was mainly due to the radiation of far-infrared rays. In contrast, in the case of Examples 1, 2, and 5 and Comparative Examples 1 and 2 having the heat-fusible resin material 22 with no fine particles of a highly thermally conductive material dispersed therein, the surface temperature rise of the black cloth for measurement was small, about 1°C.

[0106] In this measurement, the temperature was measured using a black cloth placed 15 cm away from the sheet heater. In contrast, when the sheet heater is used as a seat heater, the seat heater and the human body are in close contact. In this case, the feeling of warmth of the human body due to far infrared rays is greater than in this embodiment.

[0107] In the case of Examples 3 and 4, which have the heat-fusible resin material 23 with fine particles of a highly thermally conductive material dispersed therein, the heat energy contains less heat ray components that are unsuitable for heating the human body, and more far-infrared components that are effective for heating the human body. It has become clear that the seat heaters using these materials can achieve energy saving effects by emitting far-infrared rays.

[0108] <Durability of sheet heater against seating stress> In the cases of Examples 1 to 5, wrinkles were formed in the heat-fusible resin layer 32 after the test, but the heat-fusible resin layer 32 was not destroyed. In the cases of Examples 2 to 4, the heat-fusible resin layer 32 was not broken and the aluminum particles 26 or the nonwoven fabric 21 to which the aluminum particles 26 were attached did not come out onto the surface of the sheet heater 1. In the cases of Examples 3 and 4, the heat-fusible resin layer 32 was not destroyed and scattering of minute pieces containing graphite was not observed. On the other hand, in the case of Comparative Example 1, cracks were formed on the edges of most of the many pinholes that were formed.

[0109] In this way, it was confirmed that the heat-sealable resin layer 32 having the recesses 33 has sufficient durability against seating stress. It was also confirmed that the heat-sealable resin layer 32 having the recesses 33 can sufficiently protect the aluminum particles 26 attached to the nonwoven fabric 21, and provide high safety.

[0110] <Antistatic ability> In the case of Examples 3 and 4, which have aluminum particles 26 and heat-fusible resin material 23 having dispersed therein fine particles of high thermal conductivity material, the charging voltage was relatively low, while in the case of Examples 1, 5 and Comparative Example 2, which do not have either aluminum particles 26 or heat-fusible resin material 23 having dispersed therein fine particles of high thermal conductivity material, the charging voltage was relatively high.

[0111] Comparing the cases of Examples 3 and 4 having the heat-sealing resin material 23 in which the aluminum particles 26 and the particles of the high thermal conductivity material are dispersed with the cases of Example 2 and Comparative Example 1 having only the aluminum particles 26, the charging voltage was relatively low in the cases of Examples 3 and 4 having the heat-sealing resin material 23 in which the particles of the high thermal conductivity material are dispersed. From this, it was found that the charged static electricity is not consumed much in the aluminum particles 26 which have a low resistance value and are excellent as an electric circuit, but is consumed relatively quickly in the heat-sealing resin material 23 in which the particles of the high thermal conductivity material having a moderate high resistance are dispersed. In this way, it was revealed that the heat-sealing resin material 23 in which the particles of the high thermal conductivity material are dispersed functions as an antistatic body. It was revealed that the seat heater using the heat-sealing resin material 23 in which the particles of the high thermal conductivity material are dispersed can reduce various noises caused by static electricity compared to the seat heater using the heat-sealing resin material 22 in which the particles of the high thermal conductivity material are not dispersed.

[0112] As described above, the seat heater using the heater wire holding substrate 10 according to the embodiment can use a cord-shaped heating element whose reliability has been guaranteed. The seat heater using the heater wire holding substrate 10 according to the embodiment has a fast temperature rise rate, consumes little power, and can achieve energy saving, even if the heater wire holding substrate is made of a thin nonwoven fabric with a low basis weight.

[0113] In addition, the seat heater using the heater wire holding substrate 10 according to the embodiment is resistant to seating stress, has a high degree of freedom in design, and is excellent in cost performance. Furthermore, the seat heater using the heater wire holding substrate 10 including the heat-fusible resin material 23 in which fine particles of a high thermal conductivity material are dispersed has a function suitable for heating the human body by far-infrared radiation, and also has an antistatic function.

[0114] Although the present invention has been described above by showing preferred embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

Claims

1. A nonwoven fabric layer including a nonwoven fabric; a heat-sealable resin layer containing an extruded heat-sealable resin material and heat-sealed onto the nonwoven fabric layer; Equipped with the nonwoven fabric layer is a nonwoven fabric structure having aluminum fine particles attached to a surface of the nonwoven fabric, The nonwoven fabric layer and the heat-sealable resin layer that are heat-sealed have a plurality of recesses in which the heat-sealable resin layer penetrates in a depth direction of the nonwoven fabric layer, a mixed adhesive layer in which the nonwoven fabric and the thermal adhesive resin material are mixed is formed by the recess, In the recess, the amount of sinking of the surface of the nonwoven fabric layer is 10 μm or more and is equal to or less than the thickness dimension of the thermally adhesive resin layer. Heater wire holding substrate.

2. The nonwoven fabric has a basis weight of 80 g / m ２ Above, 350g / m ２ The heater wire-holding substrate according to claim 1 , wherein:

3. The maximum width of each of the recesses on the surface of the heat-sealable resin layer is 1 mm or more, and one or more of the recesses are provided per 5 cm square. The heater wire-holding substrate according to claim 1 or 2.

4. The thermally adhesive resin layer is formed of a polyolefin resin, The thickness of the heat-sealable resin layer is 0.03 mm to 0.5 mm. The heater wire-holding substrate according to claim 1 or 2.

5. 2. The heater wire holding substrate according to claim 1, wherein the heat-fusible resin layer is a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in a heat-fusible resin.

6. 2. The heater wire holding substrate according to claim 1, wherein the heat-fusible resin layer is a structure in which a layer formed of a heat-fusible resin structure in which fine particles of a high thermal conductivity material are dispersed in a heat-fusible resin and a layer formed of a heat-fusible resin are laminated.

7. 7. The heater wire holding substrate according to claim 5, wherein the fine particles of the high thermal conductivity material are fine particles of at least one of aluminum, copper, alumina, magnesia, and graphite.

8. The heater wire-holding substrate according to claim 1 , wherein the heat-fusible resin layer has wrinkles on a surface thereof.

9. Providing a nonwoven material comprising a nonwoven fabric; Providing a heat-sealable resin material including an extruded heat-sealable resin; the thermally adhesive resin material is placed on top of the nonwoven fabric material, and the thermally adhesive resin material is pressed and thermally fused to the nonwoven fabric material over its entire surface by a hot press equipped with an upper die having protrusions; Including, a heater wire holding substrate is formed by the press heat fusion, the heater wire holding substrate having a nonwoven fabric layer made of the nonwoven fabric material and a heat fusion resin layer made of the heat fusion resin material, the heat fusion resin material having a plurality of recesses penetrating in a depth direction of the nonwoven fabric material by melting due to heating, the recesses forming a mixed fixed layer in which the nonwoven fabric layer and the heat fusion resin layer are mixed, and an amount of sinking of the surface of the nonwoven fabric layer in the recesses is 10 μm or more and is equal to or less than a thickness dimension of the heat fusion resin layer; A method for manufacturing a heater wire holding substrate.

10. The nonwoven fabric material is a nonwoven fabric structure having aluminum fine particles attached to a surface of the nonwoven fabric, Providing the nonwoven material includes: depositing aluminum particles on the surface of the nonwoven fabric by vapor deposition; spraying an adhesive containing fine aluminum particles onto the surface of the nonwoven fabric; Including any of the following: A method for producing the heater wire-holding substrate according to claim 9.

11. preparing the heat-fusible resin material includes heat-shrinking the heat-fusible resin material including the extruded heat-fusible resin to make it wrinkled; The heat-fusible resin layer has wrinkles on the surface. A method for producing the heater wire-holding substrate according to claim 9 or 10.

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