JP2009117037A - Exothermic wire for seat heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase flexing resistance without spoiling other characteristics required for an exothermic wire for a seat heater such as mechanical strength, flexibility and soldering property. <P>SOLUTION: The exothermic wire for the seat heater is composed of a covered wire 10 with a low-friction layer 13 of super high molecular weight polyethylene on its surface layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heating wire for a seat heater used for heating a seat of an automobile or the like.

  In general, sheet heaters for automobiles are generally used as a heating wire, in which about 6 to 40 coated wires coated with polyurethane are coated on a conductor made of a copper alloy wire containing silver (for example, patents). Reference 1). The use of a copper alloy wire containing silver is due to having the bending resistance and appropriate electrical resistance required for this type of application. In addition, polyurethane is selected because of its high mechanical strength, excellent flexibility, and automatic soldering when manufacturing a seat heater.

  However, in such a conventional heating wire, the copper alloy wire itself constituting the conductor is excellent in bending resistance, but the bending resistance is not always sufficient due to the polyurethane coating. That is, when the above-described stranded wire is repeatedly bent, the coating is worn due to friction between the coated wires, and there is a possibility that the wire may be broken at the end.

As a countermeasure against this problem, for example, it is conceivable to reduce the friction of the coated wire by coating the coated surface with a low friction material such as a fluororesin or by incorporating a lubricant in the coating. However, in the former case, the polyurethane may melt when the fluororesin is coated, and in the latter case, the inherent properties of the polyurethane may be impaired by the blending of the lubricant.
JP 2006-4750 A

  The present invention has been made to solve the above-described problems of the prior art, and without impairing other characteristics required for the heating wire for the seat heater, such as mechanical strength, flexibility, and solderability. An object of the present invention is to provide a heating wire for a seat heater that can improve bending resistance.

  In order to achieve the above object, the invention according to claim 1 is a heating wire for a seat heater, characterized in that it comprises a coated wire having a low friction layer made of ultrahigh molecular weight polyethylene as a surface layer.

  The invention according to claim 2 is the seat heater according to claim 1, wherein the low friction layer has a dynamic friction coefficient (JIS K 7125) of 0.07 to 0.22. Heating wire for use.

  The invention according to claim 3 is the heating wire for seat heater according to claim 1 or 2, wherein the low friction layer has a thickness of 2 to 10 μm.

  According to a fourth aspect of the present invention, in the heating element for a seat heater according to any one of the first to third aspects, the weight average molecular weight of the ultrahigh molecular weight polyethylene is 3.5 million or more. It is a heating wire.

  According to a fifth aspect of the present invention, in the heating wire for a seat heater according to any one of the first to fourth aspects, a coating made of polyurethane is provided on a conductor, and the low friction layer is provided on the polyurethane coating. It is the heating wire for sheet heaters characterized by being formed.

  The invention according to claim 6 is the heating wire for seat heater according to any one of claims 1 to 5, wherein the polyurethane coating has a thickness of 10 to 20 μm. It is.

  The invention according to claim 7 is the heating wire for the seat heater according to any one of claims 1 to 6, wherein the heating wire for the seat heater is formed by twisting a plurality of the covered wires. .

  According to the present invention, the bending resistance can be improved without impairing other characteristics required for the heating wire for the seat heater, such as wear resistance, flexibility, and solderability.

  Embodiments of the present invention will be described below with reference to the drawings. Although the description will be made based on the drawings, the drawings are provided for illustration only, and the present invention is not limited to the drawings.

  FIG. 1 is a cross-sectional view showing a covered wire 10 constituting a heating wire for a seat heater of an automobile according to an embodiment of the present invention. Although not shown, a plurality of such covered wires 10, for example, 6 to 40, are shown. The heating wire for the seat heater of the automobile according to the present embodiment is configured by performing the collective twisting.

  As shown in FIG. 1, the covered wire 10 has a structure in which a polyurethane coating layer 12 and a low friction layer 13 are sequentially coated on a conductor 11.

  The conductor 11 is made of a metal material having good electrical resistance, excellent mechanical properties such as bending resistance, and good heat resistance and oxidation resistance. Specifically, for example, a copper silver alloy (silver content 2 to 14% by mass) is used. The wire diameter of the conductor 11 is not particularly limited, but is usually 0.02 to 0.10 mm, preferably 0.03 to 0.07 mm, from the viewpoint of comfort as a seat heater. .

  The material of the polyurethane coating layer 12 is preferably, for example, a polyurethane varnish used for a coating layer of enameled wire, and is formed by applying and baking on the conductor 11. The thickness of the polyurethane coating layer 12 is preferably in the range of 10 to 20 μm, and more preferably in the range of 13 to 17 μm. When the thickness is less than 10 μm, the insulating properties are insufficient, and when it exceeds 20 μm, the flexibility is lowered.

  The low friction layer 13 is formed by extrusion-coating ultrahigh molecular weight polyethylene onto the polyurethane coating layer 12. Since ultra-high molecular weight polyethylene can be extrusion coated below the melting temperature of polyurethane, it can be coated without impairing the properties of the polyurethane coating layer 12. As the ultra high molecular weight polyethylene, those having a weight average molecular weight of 3.5 million or more measured based on the viscosity method (ASTM D2857) are preferable, those having 3.5 million to 6.5 million are more preferable, and those having 5.5 million to 6.5 million are more preferable. Even more preferable. If the average molecular weight is less than 3.5 million, the coefficient of friction becomes large and the effects of the present invention cannot be obtained sufficiently. Specifically, Saxin Newlite (trade name) manufactured by Onaga Dream Co., Ltd. having a weight average molecular weight of about 5.5 million is preferably used.

  For the purpose of the present invention, the low friction layer 13 preferably has a dynamic friction coefficient of 0.07 to 0.22, more preferably 0.07 to 0.10. That is, when the dynamic friction coefficient of the low friction layer 13 exceeds 0.22, the bending resistance cannot be sufficiently improved, and it is difficult to form the low friction layer 13 having a dynamic friction coefficient of less than 0.07. . Further, the thickness of the low friction layer 13 is preferably in the range of 2 to 10 μm, and more preferably in the range of 4 to 8 μm. If the thickness is less than 2 μm, the bending resistance cannot be sufficiently maintained. On the other hand, if it exceeds 10 μm, the flexibility is lowered, and the solderability is also hindered.

  In the heating wire for the seat heater of the present embodiment, since it is constituted by a coated wire having a low friction layer made of ultrahigh molecular weight polyethylene on the surface layer, the bending resistance is improved and the mechanical strength, flexibility, Other characteristics required for the heating wire for the sheet heater such as solderability are also good.

  In addition, although the heating wire for seat heaters of the present invention is useful as a heating wire for seat heaters of automobiles, it goes without saying that it can be widely used for other purposes.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Examples 1-3
Polyurethane is coated and baked to a thickness of 15 μm on a conductor made of a copper-silver alloy wire (silver content: 10 mass%) with a wire diameter of 50 μm, and then ultra-high molecular weight polyethylene (trade name: Saxin New Light, manufactured by Onaga Dream Co., Ltd.) ) Was extrusion coated to the thickness shown in Table 1 to form a low friction layer with a dynamic friction coefficient of 0.15 to obtain a coated wire. Next, six of each of the obtained coated wires was gathered and twisted to produce a heating wire for a seat heater.

  The heating resistance for the sheet heater obtained in the above example was evaluated by the following method.

  As shown in FIG. 2, in a state where a load of 200 g is applied to one end of a sample 21 having a length of 1 m cut out from the heating wire for a seat heater obtained in each example, bending with a bending radius of 5 mm is repeated to the right and left to break. The number of times of bending until n was measured (n = 3). The results are shown in Table 1. In addition, the result of having performed the evaluation similar to an Example about the conventional type | formula heating wire for sheet heaters manufactured similarly to the Example except not having formed the low friction layer was combined with Table 1, and was shown together as a comparative example. .

  As is apparent from Table 1, the heating wire for the seat heater of the example was broken at a number of times of bending that was about three times that of the comparative example, and it was confirmed that the bending resistance was greatly improved.

It is sectional drawing which shows the covering wire which comprises the heating wire for sheet heaters of one Embodiment of this invention. It is a figure explaining the evaluation method of bending resistance.

Explanation of symbols

  10 ... covered wire, 11 ... conductor, 12 ... polyurethane coating, 13 ... low friction layer.

Claims (7)

  A heating wire for a seat heater, comprising a coated wire having a low friction layer made of ultrahigh molecular weight polyethylene as a surface layer.   The heating wire for a seat heater according to claim 1, wherein the low friction layer has a dynamic friction coefficient (JIS K 7125) of 0.07 to 0.22.   The heating wire for a seat heater according to claim 1 or 2, wherein the low friction layer has a thickness of 2 to 10 µm.   The heating wire for a seat heater according to any one of claims 1 to 3, wherein the ultrahigh molecular weight polyethylene has a weight average molecular weight of 3.5 million or more.   The heating wire for a seat heater according to any one of claims 1 to 4, wherein a coating made of polyurethane is provided on the conductor, and the low friction layer is provided on the polyurethane coating.   The heating wire for a seat heater according to any one of claims 1 to 5, wherein the polyurethane coating has a thickness of 10 to 20 µm.   The heating wire for a seat heater according to any one of claims 1 to 6, wherein a plurality of the covered wires are twisted together.

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