JPS6314821B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a surface heating element.

As a manufacturing method for a surface heating element, conductive fibers such as carbon fibers are dispersed in a thermosetting resin, and a glass fiber sheet is impregnated with the conductive fibers on both sides of a conductive sheet molding material (hereinafter referred to as a conductive layer). A method is already known in which insulating sheet molding materials (hereinafter referred to as insulating layers) made of thermosetting resin-impregnated glass fiber sheets are laminated and hot-press-molded. In such a method, conventionally, the end of the electrode is drawn out onto an insulating layer laminated to a conductive layer, exposed, and the conductive layer and insulating layer are hot-pressed, and the end of the electrode buried in the insulating layer is removed. are extracted by post-processing of the insulating layer. According to this method, the shape of the electrode is limited to a thin plate or a band, and in the case of a braided wire made of thin wires, it is difficult to take out the electrode by post-processing when it is buried in the insulating layer. .

The present invention has been made in view of the above, and includes:
It is an object of the present invention to provide a method for manufacturing a surface heating element, which does not require post-processing of the insulating layer regardless of the shape of the electrode, and allows the end portion of the electrode to be taken out immediately after hot press forming.

The present invention provides a method for manufacturing a surface heating element by laminating an insulating layer on a conductive layer and hot-pressing the layer, in which the ends of the electrodes connected to the conductive layer are exposed to the outside of the insulating layer. The electrode end is covered with a film that is stable under the conditions of hot press molding and has mold releasability for the thermosetting resin forming the insulating layer, and hot press is applied onto the electrode end. Place a stable plate member under molding conditions, hot-press-form the conductive layer and insulating layer, form a recess corresponding to the plate member, and expose the electrode end in this recess. This feature is characterized in that it allows the user to

The present invention will be described below based on drawings showing examples.

FIG. 1 shows each layer before hot pressing. The conductive layer 1 is preferably formed by dispersing conductive layer fibers in a thermosetting resin together with fillers and thickeners as necessary and impregnating the glass fiber sheet with current-carrying layers disposed along the edges of the conductive layer 1. The end portion 3 of the electrode 2 is exposed to the outside of the insulating layer 4 and covered with a film 5. In addition to the above-mentioned conductive layer 1,
It may be a sheet made from a mixture of conductive fibers and organic fibers, a sheet made by dispersing conductive fibers in a thermosetting resin, or the like.

Steel fibers, stainless steel fibers, carbon fibers, etc. are used as the conductive fibers, and carbon fibers are preferably used. The conductive layer has a sheet resistance (i.e., the value obtained by multiplying the resistance between two spaced electrodes by the length of the electrodes/distance between the electrodes) in the range of 1 to 1000 Ω□. desirable.

The insulating layer 4 is preferably formed by impregnating a glass fiber sheet with a resin composition containing a thermosetting resin and, if necessary, a filler, a thickener, and the like.

Unsaturated polyester resin or epoxy resin is preferably used as the thermosetting resin used for the insulating layer and, if necessary, the conductive layer, and glass fiber chopped strand mat is usually preferably used for the glass fiber sheet. glass fiber paper,
A filament mat or the like may also be used if necessary.

The film 5 covering the electrode end 3 is required to be stable under the conditions of hot press molding of a laminate of an insulating layer and a conductive layer, and to have mold releasability to the thermosetting resin used. However, cellophane, polyester film, polytetrafluoroethylene film, etc. are preferably used.

A plate member 6 is placed on the end of the electrode coated in this way.
is placed. This plate member is also stable under hot pressure molding conditions, and preferably has elasticity and mold releasability with respect to the thermosetting resin used, such as epoxy resin, polytetrafluoroethylene, various synthetic rubbers, etc. However, silicone rubber is preferably used because it has all of the properties of heat resistance, elasticity, and mold releasability. Advantageously, this plate member also has a thickness approximately equal to the insulating layer on the side from which the electrode end is taken out.

When each layer is laminated as described above and hot-pressed in a hot mold, the electrode end 3 on the insulating layer is covered and protected by the film 5, so the thermosetting resin will not adhere to it. Since it is held in place by the plate member 6, it can be immersed into the insulating layer 4 without changing its position.

After the resin has hardened, except for the plate member, a recess 7 is formed on the surface of the insulating layer corresponding to the plate member, and the film-covered electrode end is exposed inside this recess 7, as shown in FIG. . Since the film has releasability from the resin, if this film is removed, the electrode end 3 will remain exposed in the recess. In addition, when the plate member has elasticity, it will come into close contact with the entire surface of the electrode end during hot press molding, so the flowing resin will not penetrate between it and the electrode, and it will also come into close contact with the hot mold surface. The resin does not penetrate between the plate member and the mold surface, and as a result,
An attractive recess is formed according to the shape of the plate member, and connection to an external power source can be easily made.

Note that the hot pressure molding conditions depend on the resin used, but in the case of unsaturated polyester, the temperature is 100-200°C.
℃, pressure is about 10-100Kg/ ^cm2 .

As described above, according to the method of the present invention, there is no resin adhering to the electrode during hot press forming, and the end of the electrode is left exposed in the recess corresponding to the shape of the plate member. It is easy to connect to the insulating layer, and there is no need for the conventional process of post-processing the insulating layer to take out the electrodes.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing each layer before hot-pressing forming by the method of the present invention, and Fig. 2 is a cross-sectional view of a surface heating element obtained by hot-pressing forming each layer shown in Fig. 1. It is a diagram. DESCRIPTION OF SYMBOLS 1... Conductive layer, 2... Electrode, 3... Electrode end, 4... Insulating layer, 5... Film, 6... Plate member, 7... Recess.

Claims (1)

[Claims] 1. A method for manufacturing a surface heating element by laminating an insulating layer on a conductive layer and hot-pressing the layer, in which an end of an electrode connected to the conductive layer is exposed to the outside of the insulating layer. Then, the electrode end is covered with a film that is stable under the conditions of hot pressing and has mold releasability for the thermosetting resin forming the insulating layer, and the electrode end is A stable plate member is placed under the conditions of hot press forming, and the conductive layer and insulating layer are hot press formed.
A method for manufacturing a surface heating element, characterized in that a recess is formed corresponding to the plate member, and an electrode end portion is exposed within the recess. 2. The method for manufacturing a surface heating element according to claim 1, wherein the plate member has elasticity.