Heater unit and vehicle seat

Abstract

To provide a heater unit which is excellent in air permeability and mechanical strength.SOLUTION: A heater unit has: a backing material 11; and a cord-like heater 10. The cord-like heater 10 is disposed on the backing material 11 and fixed thereto. The backing material 11 is formed by combining fiber threads 11a arranged in a substantially planar form and a non-woven cloth. The fiber threads 11a comprise at least a first fiber thread group 11x, arranged linearly relative to a predetermined direction, and a second fiber tread group 11y, arranged linearly relative to a direction different from that of the first fiber thread group. The cord-like heater 10 is disposed on the backing material 11 in a meander shape formed by combining straight line parts 10a and curved line parts 10b. Each straight line part 10a of the cord-like heater 10 is arranged at an angle different from angles of the first fiber tread group 11x and the second fiber tread group 11y. The heater unit is disposed in a vehicular seat.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a heater unit that can be suitably used in electric blankets, electric carpets, car seat heaters, etc., and that has excellent breathability and mechanical strength. [Background technology]

[0002] Conventionally, heater units that are attached to vehicle seats and used as car seat heaters include, for example, those configured such that a cord-shaped heater with a heat-sealing portion is meandered on a base material, and the base material and the heat-sealing portion are bonded and fixed by heat fusion under heat and pressure (see, for example, Patent Document 1). In recent years, vehicle seats incorporating air conditioning units have been put into practical use to further improve the comfort of the vehicle interior environment. Specifically, a known vehicle seat has breathable heater units and seat coverings, and air is blown toward the covering side through ventilation channels formed inside the seat, so that air is blown out from the surface of the vehicle seat (see, for example, Patent Document 2).

[0003] A heater unit applied to a vehicle seat incorporating such an air conditioning device is required to have particularly excellent breathability. For this reason, it is known to improve breathability by using, as the base material of the heater unit, a base material with a plurality of through holes formed therein, a base material made of a breathable material such as a spunbond nonwoven fabric or a spunlace nonwoven fabric, or a base material with a mesh structure (see Patent Documents 3 to 7). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4202071: Kurabe [Patent Document 2] Patent No. 4999455: Kurabe [Patent Document 3] Patent No. 3991750: Matsushita Electric Industrial Co., Ltd. [Patent Document 4] Patent Publication No. 2005-285602: Matsushita Electric Industrial Co., Ltd. [Patent Document 5] Patent Publication No. Hei 8-507404: Scandomec [Patent Document 6] Patent Publication No. 2015-74375: TS Tech [Patent Document 7] Patent No. 6636825: Kurabe DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] However, the base materials of the heater units described in Patent Documents 3 to 6 above suffer from a significant decrease in mechanical strength as a trade-off for breathability. In particular, heater units applied to vehicle seats are subjected to repeated loads as drivers sit and leave their seats, but no heater units have been able to withstand such loads without deformation or breakage. Furthermore, base materials with multiple through holes only offer a slight improvement in breathability, and further improvement in breathability is still needed.

[0006] The heater unit described in Patent Document 7 solves the problems of the heater units described in Patent Documents 3 to 6. However, further improvement in breathability was required, and there was a demand to reduce the density (basis weight) of the nonwoven fabric. This reduces the mechanical strength and rigidity of the substrate, making it more susceptible to breakage and deformation. If the substrate is deformed, it can be difficult to install the heater unit in a vehicle seat, for example, and it can also lead to the heater unit being installed in a location not intended by the design. Therefore, there was a need to further reinforce the mechanical strength and rigidity of the heater unit.

[0007] The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a heater unit that is excellent in breathability and mechanical strength. [Means for solving the problem]

[0008] In order to achieve the above object, the heater unit according to the present invention has a base material and a cord-shaped heater, and the cord-shaped heater is disposed and fixed on the base material, wherein the base material is formed by combining a plurality of fiber threads arranged in a substantially planar manner with a nonwoven fabric, and the plurality of fiber threads are composed of at least a first group of fiber threads arranged linearly in a predetermined direction and a second group of fiber threads arranged linearly in a direction different from that of the first group of fiber threads, the cord-shaped heater is arranged on the base material in a serpentine shape consisting of a combination of straight portions and curved portions, and the straight portions of the cord-shaped heater are arranged at an angle different from that of the first group of fiber threads and the second group of fiber threads. It is also conceivable that the fiber threads are woven or overlapped with each other in different directions, and have openings larger than the apparent diameter of the fiber threads. It is also conceivable that the substrate is made of a fiber thread and a pair of nonwoven fabrics, and the fiber thread is sandwiched between the pair of nonwoven fabrics. It is also conceivable that a heat-sealed portion is formed on the outermost layer of the cord-shaped heater, and the heat-sealed portion is fixed to the nonwoven fabric and the fiber yarn by heat fusion. A vehicle seat according to the present invention includes a seat cover and a seat pad, and the heater unit is disposed between the seat cover and the seat pad. [Effects of the Invention]

[0009] Generally, reducing the amount of fiber per unit area of ​​the substrate is effective in improving breathability, but this also significantly reduces the mechanical strength and rigidity of the substrate. However, with the heater unit of the present invention, tensile strength is achieved by the fiber threads arranged in a substantially planar shape. Therefore, even a substrate with improved breathability has excellent mechanical strength. Furthermore, since the direction of the fiber thread and the direction of the straight portion of the cord-shaped heater are at different angles, the shape of the substrate can be maintained even by the cord-shaped heater. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an embodiment of the present invention, and is a plan view showing the configuration of a heater unit. [Figure 2] FIG. 1 is a diagram showing an embodiment of the present invention, and is a partially cutaway perspective view showing the configuration of a base material. [Figure 3] 1 is a diagram showing an embodiment of the present invention, and is a partially cutaway side view showing the configuration of a cord-shaped heater. FIG. [Figure 4] 1 is a diagram showing an embodiment of the present invention, illustrating the configuration of a hot press heater manufacturing apparatus. FIG. [Figure 5] FIG. 1 is a diagram showing an embodiment of the present invention, and is a partial perspective view showing how cord-shaped heaters are arranged in a predetermined pattern. [Figure 6] FIG. 2 is an enlarged plan view showing a portion of a heater unit with the base material being transparent, illustrating an embodiment of the present invention. [Figure 7] FIG. 2 is an enlarged cross-sectional view of a portion of a heater unit according to an embodiment of the present invention. [Figure 8] 1 is a perspective view showing an embodiment of the present invention, with a part cut away, illustrating a heater unit embedded in a vehicle seat; [Figure 9] FIG. 10 is a diagram showing another embodiment of the present invention, and is a partially cutaway side view showing the configuration of a cord-shaped heater. [Figure 10] FIG. 10 is a diagram showing another embodiment of the present invention, and is a partially cutaway side view showing the configuration of a cord-shaped heater. [Figure 11] FIG. 10 is a partially cutaway side view showing the configuration of a cord-shaped heater according to another embodiment of the present invention. [Figure 12] FIG. 10 is a diagram showing another embodiment of the present invention, and is a partially cutaway side view showing the configuration of a cord-shaped heater. [Figure 13] FIG. 10 is a diagram showing another embodiment of the present invention, and is a partially cutaway perspective view showing the configuration of another type of base material. [Figure 14] 1 is a photograph showing an embodiment of the present invention, and is an enlarged photograph of a main part of a heater unit. [Figure 15] 1 is a photograph showing an embodiment of the present invention, and is an enlarged photograph of a cross section of a main part of a heater unit. BEST MODE FOR CARRYING OUT THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. These embodiments show examples in which the present invention is applied to a vehicle seat heater.

[0012] First, the structure of the cord-shaped heater 10 in the first embodiment will be described. The cord-shaped heater 10 in the present embodiment is configured as shown in FIG. 3. The heater core 3 is made of a bundle of aromatic polyamide fibers with an outer diameter of approximately 0.2 mm. Six conductor wires 5a, each made of tin-plated hard tin-cored copper alloy wire (TH-SNCC-3) with an element diameter of 0.08 mm, are wound spirally around the heater core 3 at a pitch of approximately 0.7 mm. The conductor wires 5a wound around the heater core 3 are then extruded and coated with an insulating layer 7 of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) with a thickness of approximately 0.15 mm, thereby forming the heating wire 1. The heating wire 1 is further extruded and coated with a polyester resin blended with a flame retardant with a thickness of 0.2 mm as the heat-sealable portion 9. The cord-shaped heater 10 has this structure and a finished outer diameter of 1.1 mm. Furthermore, while the heater wick 3 is effective when considering flexibility and tensile strength, it is also possible to use multiple heating element wires drawn together or twisted together instead of the heater wick 3. Furthermore, if the cord-shaped heater 10 itself has flame retardancy that passes the UL1581 horizontal flame test: 2008, 4th edition, this is preferable because it can improve the flame retardancy of the heater unit.

[0013] Next, the structure of the substrate 11 to which the cord-shaped heater 10 having the above-mentioned structure is adhered and fixed will be described. As shown in Fig. 2, the substrate 11 in this embodiment is made by plain weaving fiber yarns 11a made of polyester multifilament with an apparent diameter of 0.5 mm with a lattice spacing of 10 mm, openings 11c of 9.5 mm in size, and a shielding rate of 12.9%, which is then bound to a pair of nonwoven fabrics 11b (basis weight 27 g / m) made of flame-retardant polyester fiber. 2 2) and adhered with an adhesive. That is, the fiber threads 11a are composed of a first fiber thread group 11x arranged linearly in the left-right direction in FIG. 2 and a second fiber thread group 11y arranged linearly in the front-rear direction in FIG. 2. This nonwoven fabric is obtained by melt-extruding and spinning the material constituting the fibers, and laminating them to form a web, and is made of filaments (long fibers). The fiber threads 11a are sandwiched between a pair of such nonwoven fabrics 11b, and are fixed with an adhesive. The intersections of the fiber threads 11a are also fixed with an adhesive. The substrate 11 having such a configuration has an overall basis weight of 100 g / m 2 It is as follows.

[0014] Next, a configuration for disposing, adhering, and fixing the cord heater 10 in a serpentine shape on the substrate 11 will be described. In this embodiment, the meandering interval is 20 mm. FIG. 4 shows the configuration of a hot-press heater manufacturing apparatus 13 for adhering and fixing the cord heater 10 to the substrate 11. First, there is a hot-press jig 15, on which a plurality of locking mechanisms 17 are provided. As shown in FIG. 5, the locking mechanism 17 has a pin 19, which is inserted from below into a hole 21 drilled in the hot-press jig 15. A locking member 23 is attached to the top of the pin 19 so as to be movable in the axial direction and is constantly biased upward by a coil spring 25. Then, as shown by the phantom lines in FIG. 5, the cord heater 10 is disposed in a serpentine shape while being hooked onto the locking members 23 of the plurality of locking mechanisms 17.

[0015] Returning to FIG. 4 , a press hot plate 27 is arranged above the multiple locking mechanisms 17 in a manner that allows it to be raised and lowered. Specifically, the cord-shaped heater 10 is arranged in a serpentine shape, hooked onto the locking members 23 of the multiple locking mechanisms 17, and the substrate 11 is placed on top of it. In this state, the press hot plate 27 is lowered to apply heat and pressure to the cord-shaped heater 10 and the substrate 11 at, for example, 230°C for 5 seconds. This causes the heat-sealable portion 9 on the cord-shaped heater 10 to fuse with the heat-sealable fiber on the substrate 11, thereby adhering and fixing the cord-shaped heater 10 to the substrate 11. When the press hot plate 27 is lowered to apply heat and pressure, the locking members 23 of the multiple locking mechanisms 17 move downward against the biasing force of the coil springs 25.

[0016] As shown in FIG. 6 , the serpentine shape of the cord-like heater 10 is formed by combining straight portions 10a and curved portions 10b. In this case, as in the present embodiment, it is preferable that the straight portions 10a of the cord-like heater 10 are arranged so as to form an angle different from that of the first fiber thread group 11x and the second fiber thread group 11y. The mechanical strength of the substrate 11 is high in the direction in which the fiber threads 11a are arranged, but when pulled at an angle different from that of the fiber threads 11a, the substrate becomes more susceptible to deformation as the angle changes. In particular, when the first fiber thread group 11x and the second fiber thread group 11y are arranged perpendicular to each other, as in the present embodiment, the substrate is most susceptible to deformation when pulled at an angle 45 degrees from that of the first fiber thread group 11x. By forming the straight portions 10a of the cord-like heater 10 at an angle different from that of the first fiber thread group 11x and the second fiber thread group 11y, the substrate becomes less susceptible to deformation even when pulled at various angles. In FIG. 6, the nonwoven fabric 11b of the base material 11 is shown in a see-through manner.

[0017] An adhesive layer may be formed on the surface of the base material 11 on which the cord-shaped heater 10 is not provided, or double-sided tape may be attached to fix the heater unit 31 to the seat when attaching it to the seat.

[0018] By performing the above steps, a heater unit 31 for a vehicle seat heater can be obtained as shown in Fig. 1. Note that cords are connected to both ends of the cord-shaped heater 10 and to the temperature control device 39 in the heater unit 31, and these cords connect the cord-shaped heater 10, the temperature control device 39, and the connector 35. The heater unit 31 is then connected to the vehicle's electrical system (not shown) via the connector 35.

[0019] The heater unit 31 having the above-described configuration is disposed embedded in a vehicle seat 41 in a state as shown in Fig. 8. That is, as described above, the heater unit 31 is attached to the seat cover 43 or the seat pad 45 of the vehicle seat 41.

[0020] In the heater unit obtained in the above embodiment, the heat-sealed portion 9 of the cord-shaped heater 10 penetrates into the nonwoven fabric 11b of the base material 11 and surrounds the fibers that make up the nonwoven fabric 11b, thereby firmly bonding the cord-shaped heater 10 to the base material 11. In particular, if the base material 11 contains heat-sealed fibers that have a core-sheath structure and the sheath portion has a low melting point, the sheath portion and the heat-sealed portion 9 of the cord-shaped heater will fuse together and become integrated while surrounding the core portion. This further strengthens the bond between the cord-shaped heater 10 and the base material 11.

[0021] As shown in the enlarged cross-sectional view of FIG. 7, the heat-sealed portion 9 of the cord-like heater 10 penetrates beyond the nonwoven fabric 11b of the substrate 11 until it directly contacts the fiber yarn 11a, and the heat-sealed portion 9 and the fiber yarn 11a are preferably fixed by heat fusion. Improving the breathability of the substrate 11 reduces the density (basis weight) of the nonwoven fabric 11b of the substrate 11, which can easily cause the cord-like heater 10 to peel due to fiber shedding from the nonwoven fabric 11b. Directly fixing the heat-sealed portion 9 and the fiber yarn 11a can prevent such peeling. Furthermore, the cord-like heater 10 and the fiber yarn 11a are firmly integrated, which also has the effect of making the heater unit less likely to deform. FIGS. 14 and 15 show enlarged photographs of the essential parts of the heater unit. FIG. 14 is a photograph of the heater unit taken from the side of the substrate opposite to the side where the cord-like heater is fixed. Figure 15 is a photograph of the cross section of a heater unit cut along the direction of the cord-shaped heater. In both Figures 14 and 15, it can be seen that the heat-sealed portion of the cord-shaped heater surrounds the fiber yarn, and that the heat-sealed portion and the fiber yarn are fixed together by heat fusion.

[0022] The present invention is not limited to the above-described embodiment. Various conventionally known cord-shaped heaters can be used for the cord-shaped heater 10. Examples of the configuration of the heating wire 1 include, as in the above-described embodiment, a configuration in which multiple conductor wires 5a are twisted or aligned, wound around a core wire 3, and an insulating layer 7 is applied to the outer periphery (see FIG. 3); a configuration in which multiple conductor wires 5a coated with an insulating coating 5b are twisted together (see FIG. 9); a configuration in which multiple conductor wires 5a coated with an insulating coating 5b are aligned (see FIG. 10); a configuration in which multiple conductor wires 5a coated with an insulating coating 5b are twisted or aligned and wound around a core wire 3 (see FIG. 11); and a configuration in which heat-sealed portions 9 are intermittently formed (see FIG. 12). A temperature detection wire, a short-circuit detection wire, or the like may also be wound. Specific examples of such other configurations are described below. First, as shown in Figure 11, seven conductor strands 5a made of tin-copper alloy wires with a strand diameter of 0.08 mm are wound helically at a pitch of 1 mm around the heater core 3 made of a bundle of aromatic polyamide fibers with an outer diameter of approximately 0.2 mm to form the heating wire 1. The conductor strands 5a are covered with an insulating coating 5b made of polyurethane with a thickness of approximately 0.005 mm. A polyethylene resin blended with a flame retardant is extruded and coated to a thickness of 0.25 mm around the outer periphery of the heating wire 1 to form the heat-sealable portion 9. The cord-shaped heater 10 has this configuration and its finished outer diameter is 0.9 mm.

[0023] Examples of the core wire 3 include monofilaments, multifilaments, and spun yarns of inorganic fibers such as glass fibers, polyester fibers such as polyethylene terephthalate, and organic fibers such as aliphatic polyamide fibers, aromatic polyamide fibers, and wholly aromatic polyester fibers. These fiber materials, or fibers having a core made of an organic polymer material constituting these fiber materials and a thermoplastic organic polymer material covering the periphery, are also available. Furthermore, if the core wire 3 is heat-shrinkable and heat-meltable, abnormal heating in the event of a break in the conductor wire 5a melts and cuts the core wire and shrinks, causing the wound conductor wire 5a to follow the movement of the core wire 3 and separate the ends of the broken conductor wire 5a. This prevents the ends of the broken conductor wire from coming into contact with each other or from making contact with only a small area, such as a point contact, thereby preventing abnormal heating. Furthermore, as long as the conductor wire 5a is insulated by the insulating coating 5b, the insulating material of the core wire 3 is not limited. For example, stainless steel wire or titanium alloy wire could also be used. However, in consideration of what would happen if the conductor wire 5a were to break, it is better for the core wire 3 to be made of an insulating material.

[0024] The conductor wires 5a may be conventionally known, such as copper wire, copper alloy wire, nickel wire, iron wire, aluminum wire, nickel-chromium alloy wire, copper-nickel alloy, iron-chromium alloy, and silver-containing copper alloy wire in which copper solid solution and copper-silver eutectic are fibrous. Various cross-sectional shapes are also available, including those not limited to commonly used circular cross-sections but also so-called rectangular wires. However, when winding the conductor wires 5a around the core wire 3, those with a small amount of springback when the heating wire 1 is wound around them are preferred. For example, a silver-containing copper alloy wire in which copper solid solution and copper-silver eutectic are fibrous has excellent tensile strength and flexural strength, but is prone to springback when the heating wire is wound around it. Therefore, when winding the conductor wires 5a around the core wire 3, the conductor wires 5a are prone to lifting or breakage due to excessive winding tension, and are also prone to twisting after processing, making them undesirable. In particular, when the conductor wires 5a are covered with the insulating coating 5b, the restoring force of the insulating coating 5b is also added, so it is important to select conductor wires 5a with a small restoring rate to compensate for the restoring force of the insulating coating 5b.

[0025] The insulating coating 5b covering the conductor wires 5a can be made of a conventionally known resin material, such as polyurethane resin, polyamide resin, polyimide resin, polyamideimide resin, polyesterimide resin, nylon resin, polyesternylon resin, polyethylene resin, polyester resin, vinyl chloride resin, fluororesin, or silicone resin. Multiple layers of these materials may be used. Among these, a material with thermal fusion properties is preferred because it allows the conductor wires 5a to be fused together, preventing the heating wire 1 from coming apart during terminal processing, such as connecting to a connection terminal, and improving processability. Furthermore, when soldering is used for terminal processing, the insulating coating 5b is removed by the heat generated during soldering, greatly improving processability. Therefore, a material with good thermal decomposition properties is preferred for the insulating coating 5b.

[0026] When the conductor wires 5a are wound around the core material 3 by being paralleled or twisted, paralleling is preferable to twisting. This is because the diameter of the heating core 4 becomes smaller and the surface becomes smoother. In addition to paralleling or twisting, braiding the conductor wires 5a around the core material 3 is also conceivable.

[0027] The insulating layer 7 may be formed by extrusion molding or by covering it with an insulating layer 7 that has been previously formed into a tube shape; there are no particular limitations on the method of formation. The material for the insulating layer 7 may be appropriately selected depending on the usage form and environment of the cord-shaped heater, and examples of the material include polyethylene resin, polyester resin, polyurethane resin, polyamide resin, vinyl chloride resin, fluorine resin, synthetic rubber, fluorine rubber, ethylene-based thermoplastic elastomer, and urethane-based thermoplastic elastomer. A protective coating may also be formed on the outer periphery of the insulating layer 7.

[0028] When forming the heat-sealed portion 9 around the outer periphery of the heating wire 1, the heat-sealed portion may be formed around the entire periphery of the heating wire. Alternatively, the heat-sealed portion may be formed in a straight or spiral pattern along the length of the cord-shaped heater, in a dotted pattern, or intermittently as shown in FIG. 12. In this case, if the heat-sealed portion is not continuous along the length of the cord-shaped heater, even if a portion of the heat-sealed portion ignites, the burning area will not spread, which is preferable. Furthermore, if the volume of the heat-sealed portion is sufficiently small, even if the heat-sealed portion is made of a flammable material, the burning material will quickly disappear, extinguish the fire, and no drips (burning droplets) will occur. Therefore, it is preferable to keep the volume of the heat-sealed portion to the minimum necessary to maintain adhesion to the substrate. However, in these cases, it is preferable that the insulating layer 7 or insulating coating 5b be made of a flame-retardant material.

[0029] A flame-retardant polymer composition is preferably used as the material for the heat-sealed portion 9. Here, a flame-retardant polymer composition refers to one having an oxygen index of 21 or higher in the flammability test according to JIS-K7201 (1999). An oxygen index of 26 or higher is particularly preferred. Specific examples of the material include thermoplastic polymer materials such as olefin resins, polyester resins, polyamide resins, vinyl chloride resins, polyurethane resins, modified Noryl resins (polyphenylene oxide resins), aliphatic polyamide resins, polystyrene resins, polyolefin thermoplastic elastomers, polyester thermoplastic elastomers, polyurethane thermoplastic elastomers, and polyamide thermoplastic elastomers, as well as thermoplastic polymer materials containing appropriate flame retardants. Examples of olefin resins include high-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, linear low-density polyethylene, polypropylene, polybutene, ethylene-α-olefin copolymers, and ethylene-unsaturated ester copolymers. Examples of ethylene-unsaturated ester copolymers include ethylene-vinyl acetate copolymer, ethylene-methyl (meth)acrylate copolymer, ethylene-ethyl (meth)acrylate copolymer, and ethylene-butyl (meth)acrylate copolymer, and these may be used alone or in mixtures of two or more. Here, "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid. Polyester-based thermoplastic elastomers include polyester-polyester and polyester-polyether types, with polyester-polyether types being preferred due to their higher adhesive properties. Aliphatic polyamide resins, also known as nylons, include n-nylons synthesized by the polycondensation reaction of ω-amino acids and n,m-nylons synthesized by the co-condensation polymerization reaction of diamines and dicarboxylic acids. Examples of n-nylons include nylon 6, nylon 11, and nylon 12, while examples of n,m-nylons include nylon 66, nylon 610, nylon 6I, nylon 6T, nylon 9T, and nylon M5T. Known polyamide-based thermoplastic elastomers include block copolymers with polyamide hard segments and polyether soft segments.The polyamides used as the hard segments include, for example, the aliphatic polyamides described above, as well as aromatic polyamides such as para-aramid and meta-aramid. The polyethers used as the soft segments include polyalkylene ether glycols such as polyethylene glycol, poly(1,2- and 1,3-)propylene ether glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol; block or random copolymers of ethylene oxide and propylene oxide; block or random copolymers of ethylene oxide and tetrahydrofuran; and copolymers containing dihydric phenols such as bisphenol A and hydroquinone. Among these, preferred are polyamide-based thermoplastic elastomers, which have excellent adhesive properties at high temperatures and are compatible with polyester fiber nonwoven fabrics as substrates in terms of melting point and adhesive properties. Block copolymers of aliphatic polyamides and polyalkylene ether glycols are more preferred, and block copolymers of nylon 11 or nylon 12 and polytetramethylene ether glycol are particularly preferred. Any of these may be selected, but it is preferable to use a material that melts at a temperature below the decomposition temperature or melting point of the material that constitutes the insulating coating 5b or the insulating coating 7. Polyester-based thermoplastic elastomers are also examples of materials that have excellent adhesion to substrates. Furthermore, to facilitate adhesion to substrates and ensure adhesive strength after bonding, the material that constitutes the heat-sealable portion 9 should have a melt flow rate of 5.0 cm. 3Preferably, the melt flow rate is 1 / 10 minutes or more. This melt flow rate is measured at a temperature of 200°C and a load of 2.16 kg according to Method A of JIS-K7210:1999. Examples of flame retardants include metal hydrates such as magnesium hydroxide and aluminum hydroxide, antimony oxide, melamine compounds, phosphorus-based compounds, chlorine-based flame retardants, and bromine-based flame retardants. These flame retardants may be appropriately surface-treated by known methods. In particular, a surface treatment that reduces the viscosity of the polymer composition constituting the heat-sealed portion 9 when melted is preferred. The method for forming the adhesive layer 9 is not particularly limited; for example, it may be formed by known extrusion molding or coating. In the present invention, the adhesive strength between the cord-shaped heater and the substrate is extremely important. If this adhesive strength is insufficient, the substrate and the cord-shaped heater may peel off during use, which may result in unexpected bending of the cord-shaped heater and potentially breakage of the conductor wire.

[0030] Furthermore, when using a cord-shaped heater as shown in FIG. 3, a good electrical conductor such as metal foil can be wrapped around the outer periphery of the conductor wire 5a in a portion of its length. Furthermore, when using a cord-shaped heater as shown in FIG. 3, a good electrical conductor such as metal foil can be wrapped around the outer periphery of the core material 3 (the inner surface of the conductor wire 5a) in a portion of its length. By doing so, electricity is conducted to the good electrical conductor in the portion where the good electrical conductor is wrapped, but is hardly conducted to the conductor wire 5a, so that this portion does not generate heat. Therefore, it is possible to wind a good electrical conductor as described above in a portion where heat generation is not required. Furthermore, if a good electrical conductor is wrapped around the end of the cord-shaped heater as described above, that portion becomes a lead wire portion. Therefore, the heat-generating portion and the lead wire portion are formed continuously, and waterproofing is achieved without special connection processing or waterproofing processing. Therefore, such a configuration is suitable for applications requiring waterproofing, such as humid environments, environments where water is splashed, and environments where ice is melted.

[0031] Furthermore, the cord-shaped heater 10 may be provided in two or more units. In this case, one cord-shaped heater and the other cord-shaped heater may be provided on the same surface of the substrate, or on different surfaces of the substrate. A cord-shaped sensor may also be provided in conjunction with the cord-shaped heater. A cord-shaped sensor may be a cord-shaped heater as described above, in which the heating wire is replaced with a detection wire. Examples of such a cord-shaped sensor include a temperature sensor that measures the change in resistance of the detection wire due to temperature, a temperature sensor that detects electrical conductivity of the detection wire due to melting of an insulating material that melts at a predetermined temperature, a grip sensor or seat sensor that measures the change in capacitance of the detection wire, and a pressure sensor or load sensor that detects or measures the tension or displacement of the detection wire. The cord-shaped sensor may also be provided on the same surface of the substrate as the cord-shaped heater, or on different surfaces of the substrate.

[0032] The substrate 11 is made up of a combination of fiber yarns 11a and nonwoven fabric 11b arranged in a substantially planar shape. The fiber yarns 11a can be in various forms, such as multifilament, monofilament, or spun yarn. Among these, multifilament yarns are preferred because of their excellent flexibility and strength. The apparent diameter of the fiber yarns can be set appropriately depending on the usage environment of the heater unit 31, but is preferably 0.25 to 1 mm from the perspective of balancing flexibility, mechanical strength, and breathability. The apparent diameter of the fiber yarns is a value obtained by actual measurement, including the gaps between the fibers that make up the fiber yarns, and can be approximately calculated using the following formula. D=0.0357×{T / (ρ×φ)} 0.5 D: Apparent diameter of fiber thread (mm) T: Fiber thread thickness (tex) ρ: Density of the fibers that make up the fiber yarn (g / cm 3 ) φ: Filling ratio of fiber threads (ratio of apparent density of fiber threads to fiber density)

[0033] Materials that can be used to form the fiber thread 11a include, for example, inorganic fibers such as glass fiber, alumina fiber, silica fiber, alumina-silica fiber, and carbon fiber; polyester fibers such as polyethylene terephthalate fiber, polyethylene naphthalate fiber, and polybutylene terephthalate fiber; synthetic fibers such as polyvinyl alcohol fiber, polyvinyl chloride fiber, polyvinylidene chloride fiber, polyethylene fiber, polypropylene fiber, polyacrylonitrile fiber, polystyrene fiber, polyurethane fiber, polyphenylene sulfide fiber, aramid fiber, nylon fiber, polyethersulfone fiber, polyetherketone fiber, and tetrafluoroethylene fiber; and natural fibers such as cotton, hemp, flax, silk, and wool. Fibers with a core-sheath structure, in which a core made of a high-melting-point material is surrounded by a sheath made of a low-melting-point material, may also be used. These may be selected appropriately taking into account the conditions of use, etc. Of course, the fiber thread 11a may be made of a single type of fiber, or may be made of a combination of multiple types of fibers.

[0034] Examples of the configuration in which the fiber threads 11a are arranged in a substantially planar manner include a configuration in which the fiber threads 11a are arranged in a meandering pattern, a configuration in which multiple fiber threads 11a are aligned at a predetermined interval, a configuration in which multiple layers of multiple fiber threads 11a aligned at a predetermined interval and aligned in different alignment directions are stacked, a configuration in which the fiber threads 11a are woven (e.g., plain weave, twill weave, satin weave, etc.), and a configuration in which the fiber threads 11a are knitted (plain knit, rib knit, purl knit, double knit, pique knit, jacquard knit, raschel knit, tricot knit, etc.). In particular, if the fabric is woven or knitted to have openings 11c larger than the apparent diameter of the fiber threads 11a, the openings 11c can provide sufficient breathability. Furthermore, the woven or knitted structure can prevent the fiber threads 11a from shifting even when an external force is applied. The size of the opening 11c is preferably, for example, about 10 to 30 times the apparent diameter of the fiber thread 11a. The size of the opening 11c is determined by the portion of the opening 11c where the diameter is greatest; for example, if the opening 11c is rectangular, the length of the diagonal is the size of the opening 11c. From another perspective, the shielding factor of the fiber thread 11a is preferably 8.8 to 23.2%. The shielding factor is the proportion of the area occupied by the fiber thread 11a per unit area; when the apparent diameter of the fiber thread 11a is constant, the larger the size of the opening 11c, the smaller the shielding factor; and when the size of the opening 11c is constant, the larger the apparent diameter of the fiber thread 11a, the greater the shielding factor.

[0035] In the above embodiment, the angle between the first fiber thread group 11x and the second fiber thread group 11y is 90 degrees, but of course it can be a different angle. However, if this angle is too small, the mechanical strength in a predetermined direction may be insufficient, so an angle of 45 degrees or more is preferable. Furthermore, in addition to the first fiber thread group 11x and the second fiber thread group 11y, a third fiber thread group, a fourth fiber thread group, etc., with different angles may also be used. For example, as shown in FIG. 13, a substrate 11 in which the first fiber thread group 11x, the second fiber thread group 11y, and the third fiber thread group 11z are arranged at angles that differ by 60 degrees each may be considered. In the case of the embodiment shown in Figure 13, the straight portion 10a of the cord-shaped heater 10 may be arranged so that the first fiber thread group 11x, the second fiber thread group 11y, and the third fiber thread group 11z are all at different angles, but the effect of the present invention can be sufficiently obtained as long as the straight portion 10a is arranged so that the angle is different from that of two of the first fiber thread group 11x, the second fiber thread group 11y, and the third fiber thread group 11z.

[0036] Nonwoven fabric 11b may be formed by various methods, such as a wet method, a thermal bonding method, a chemical bonding method, a needle punch method, or a spunlace method. Fibers constituting nonwoven fabric 11b include inorganic fibers such as glass fiber, alumina fiber, silica fiber, alumina-silica fiber, and carbon fiber; polyester fibers such as polyethylene terephthalate fiber, polyethylene naphthalate fiber, and polybutylene terephthalate fiber; synthetic fibers such as polyvinyl alcohol fiber, polyvinyl chloride fiber, polyvinylidene chloride fiber, polyethylene fiber, polypropylene fiber, polyacrylonitrile fiber, polystyrene fiber, polyurethane fiber, polyphenylene sulfide fiber, aramid fiber, nylon fiber, polyethersulfone fiber, polyetherketone fiber, and tetrafluoroethylene fiber; and natural fibers such as cotton, hemp, flax, silk, and wool. Alternatively, heat-fusible fibers having a core-sheath structure, in which a core of high-melting-point material is surrounded by a sheath of low-melting-point material, may be used. When such heat-fusible fibers are used, if the heat-fusible portion 9 is formed on the outermost layer of the cord-shaped heater 10, the sheath of the heat-fusible fiber and the heat-fusible portion 9 are fused together and integrated while surrounding the core of the heat-fusible fiber, resulting in extremely strong adhesion between the cord-shaped heater 10 and the substrate 11. These fibers can be appropriately selected taking into account the conditions of use, etc. Of course, the nonwoven fabric 11b may be made of a single type of fiber, or a hybrid nonwoven fabric 11b made by combining multiple types of fibers. The fibers constituting the nonwoven fabric 11b may be filaments (long fibers) with no fiber length, or staples (short fibers) with a predetermined fiber length. Filaments are preferred because they provide greater strength as the nonwoven fabric 11b and also ensure reliable fixation of the cord-shaped heater 10. Furthermore, the substrate 11 is preferably flame-retardant enough to pass the FMVSS No. 302 combustion test for automotive interior layer materials. Here, FMVSS stands for Federal Motor Vehicle Safety Standard, and No. 302 of the FMVSS specifies the combustion test for automobile interior materials.For this reason, it is preferable to use flame-retardant fibers that pass a flame-retardant test (e.g., JIS-L1091:1999) as the fibers constituting the fiber yarn 11a and the nonwoven fabric 11b. The use of such flame-retardant fibers imparts excellent flame retardancy to the substrate. The thickness of the nonwoven fabric 11b (measured in a dry state) is preferably, for example, approximately 0.6 mm to 1.4 mm. If the nonwoven fabric 11b has such a thickness, when the cord-shaped heater 10 and the substrate 11 are bonded and fixed together by heat and pressure, the nonwoven fabric 11b will adhere well to at least 30%, preferably at least 50%, of the outer periphery of the cord-shaped heater, thereby achieving a strong bond. Furthermore, the basis weight (weight per unit area) of the nonwoven fabric 11b is 80 to 120 g / m for the entire substrate 11. 2 With nonwoven fabric 11b having such a basis weight, it is possible to obtain excellent breathability and sufficient mechanical strength.

[0037] When thermally adhesive fibers are used in the nonwoven fabric 11b, the blending ratio of the thermally adhesive fibers is preferably 5% or more, and more preferably 20% or less. If the blending ratio of the thermally adhesive fibers is less than 5%, sufficient adhesiveness is difficult to obtain. If the blending ratio of the thermally adhesive fibers is more than 20%, the nonwoven fabric becomes stiff, which may cause discomfort to the seat occupant and may actually reduce adhesiveness to the cord-shaped heater. The blending ratio of the flame-retardant fibers is 70% or more, and preferably 70% to 95%. If the blending ratio of the flame-retardant fibers is less than 70%, sufficient flame retardancy may not be obtained. If the blending ratio of the flame-retardant fibers is more than 95%, the blending ratio of the thermally adhesive fibers becomes relatively insufficient, making it difficult to obtain sufficient adhesiveness. The blending ratios of the thermally adhesive fibers and the flame-retardant fibers do not need to sum to 100%, and other fibers may be mixed as appropriate.

[0038] It is also possible to color the fibers that make up the nonwoven fabric 11b. For example, in the case of a vehicle seat 41 in which synthetic leather or natural leather is used as the material for the seat upholstery 43, these materials are not breathable, so multiple through-holes are formed in the seat upholstery 43 to provide breathability. When the heater unit 31 is placed in such a vehicle seat 41, the heater unit 31 will be visible through the through-holes. Therefore, it is preferable to color the fibers that make up the nonwoven fabric 11b black or a color similar to the seat upholstery so that the heater unit 31 is as inconspicuous as possible. Of course, it is also possible to color the fiber threads 11a and the cord-like heater 10 black or a color similar to the seat upholstery.

[0039] Possible combinations of the fiber yarn 11a and the nonwoven fabric 11b include, for example, a combination in which the fiber yarn 11a is attached to one side of the nonwoven fabric 11b in a planar configuration, or a combination in which the fiber yarn 11a is sandwiched between a pair of nonwoven fabrics 11b. In this case, the fiber yarn 11a and the nonwoven fabric 11b may be attached to each other with, for example, an adhesive. Furthermore, when a pair of nonwoven fabrics 11b is used, the nonwoven fabrics 11b may be attached to each other with, for example, an adhesive. Various adhesives are known, and an appropriate adhesive may be selected based on compatibility with the fiber yarn 11a and the nonwoven fabric 11b. However, given recent environmental circumstances, it is preferable to select an adhesive that takes VOCs into consideration. Furthermore, if a thermoplastic resin is used as the fiber material for the fiber yarn 11a and / or the nonwoven fabric 11b, the fiber yarn 11a and the nonwoven fabric 11b can be attached to each other by heating and pressurizing the overlapped fiber yarn 11a and the nonwoven fabric 11b under appropriate conditions. Specifically, for example, the above-mentioned method using a press hot plate or a method of passing the film between heated rolls can be mentioned.

[0040] Furthermore, when a pair of nonwoven fabrics 11b are used, they may be made of different materials. For example, the following is possible. One of the nonwoven fabrics 11b may be selected to have a high porosity, i.e., a small amount of fiber per unit volume. By making the nonwoven fabric 11b on the side where the cord-shaped heater 10 will be present on the heater unit surface have a high porosity, the cord-shaped heater 10 can be more reliably embedded in the nonwoven fabric 11b, resulting in a flat heater unit 31. Another possible solution is to make one of the nonwoven fabrics 11b have a high porosity, and then melt and fill that nonwoven fabric 11b with another resin to create a composite material. Furthermore, by combining various nonwoven fabrics, such as nonwoven fabrics with excellent flame retardancy, nonwoven fabrics with high tensile strength, nonwoven fabrics with excellent chemical resistance, nonwoven fabrics with excellent heat resistance, nonwoven fabrics with excellent voltage resistance characteristics, nonwoven fabrics with electromagnetic wave shielding properties, nonwoven fabrics with low resilience, nonwoven fabrics with excellent low-temperature brittleness, and nonwoven fabrics with high (or low) thermal conductivity, it is possible to create a heater unit 31 with additional functions.

[0041] Furthermore, in terms of the flexibility of the substrate 11 and maintaining a good texture, it is preferable that the adhesive layer for fixing the heater unit 31 to the seat be formed by forming an adhesive layer consisting only of an adhesive on a release sheet or the like and transferring the adhesive layer from the release sheet to the surface of the substrate 11. This adhesive layer is preferably flame-retardant, and preferably has flame retardancy sufficient to pass the FMVSS No. 302 combustion test for automotive interior materials by itself. For example, a polymeric acrylic adhesive may be used.

[0042] Furthermore, when the cord-like heater 10 is disposed on the substrate 11, the cord-like heater 10 may be fixed to the substrate 11 in a manner other than by adhesion and fusion bonding using heat and pressure. For example, the cord-like heater 10 may be fixed to the substrate 11 by sewing, or by sandwiching the cord-like heater 10 between a pair of adhesive-coated substrates 11, or other manners may be used. When fixing the cord-like heater 10 to the substrate 11, a preferred embodiment is one in which the cord-like heater 10 is fixed in direct contact with the fiber yarn 11a of the substrate 11. When fixing the cord-like heater 10 to the substrate 11 by sewing, for example, a substrate 11 having the fiber yarn 11a disposed on its surface or a substrate 11 having a nonwoven fabric 11b with a sufficiently small density (basis weight) may be used, so that the cord-like heater 10 and the fiber yarn 11a are sufficiently close to each other, and then they are fastened together by sewing.

[0043] The serpentine arrangement of the cord-like heater 10 can be designed to a predetermined shape by appropriately combining the straight portions 10a and curved portions 10b depending on the object to be heated, the installation location, etc. The straight portions 10a are preferably arranged so as to form a different angle from the first fiber yarn group 11x and the second fiber yarn group 11y, but this does not have to be the case for all of the straight portions 10a. A portion of the straight portions 10a may be parallel to the first fiber yarn group 11x or the second fiber yarn group 11y. The effects of the present invention can be fully achieved as long as 50% or more of the straight portions 10a of the arranged cord-like heater 10 are arranged so as to form a different angle from the first fiber yarn group 11x and the second fiber yarn group 11y. [Industrial Applicability]

[0044] As described above in detail, the present invention provides a heater unit with excellent breathability and mechanical strength. This heater unit can be suitably used as a heating means that requires breathability, such as electric blankets, electric carpets, car seat heaters, steering wheel heaters, heated toilet seats, heaters for anti-fog mirrors, heating cookware, and heaters for floor heating. [Explanation of symbols]

[0045] 10 Cord heater 10a Straight section 10b Curved section 11 Base material 11a Fiber yarn 11b Non-woven fabric 11c opening 11x First Fiber Yarn Group 11y 2nd fiber yarn group 31 Heater unit 41 Vehicle seats

Claims

1. A heater unit having a substrate and a cord-shaped heater, the cord-shaped heater being disposed and fixed on the substrate, The substrate is formed by combining a plurality of fiber yarns arranged in a substantially planar shape with a nonwoven fabric, the plurality of fiber yarns are at least comprised of a first group of fiber yarns linearly arranged in a predetermined direction and a second group of fiber yarns linearly arranged in a direction different from that of the first group of fiber yarns, the cord-shaped heater is arranged on the substrate in a serpentine shape that is a combination of straight portions and curved portions, the straight portion of the cord-shaped heater is disposed at an angle different from that of the first fiber yarn group and the second fiber yarn group, the straight line portions are arranged so as to form an angle different from that of the first fiber yarn group and the second fiber yarn group 11y in an area of ​​50% or more of the straight line portions, The fiber yarns are woven or overlapped with each other in different directions, and have openings larger than the apparent diameter of the fiber yarns; A heat-sealed portion is formed on the outermost layer of the cord-shaped heater, and the heat-sealed portion is fixed to the nonwoven fabric and the fiber yarn by heat fusion to form a heater unit.

2. 10. A vehicle seat having a seat cover and a seat pad, the heater unit according to claim 1 being disposed between the seat cover and the seat pad.

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