JPS6231987Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention relates to a planar heating element used for floor heating etc.
More specifically, the present invention relates to means for eliminating waveform distortion that occurs when forming a planar heating element in which flat knitted metal wires for electrodes are embedded.

As a molding means for extruding a molten synthetic resin mixed with a conductive filler such as carbon black or graphite powder together with an electrode metal wire, there is a method using an inflation die, a T-die, or the like.

However, in this method, (a)
The contraction rate of the metal wire used for the electrode and the resin of the main body is different, and (b) the fluidity of the resin changes due to inserting a foreign object other than resin (metal wire for electrode) inside the die. In addition, the heating element sheet discharged from the die has a small shrinkage rate near the electrodes because the metal wire used in the electrodes prevents the heating element from shrinking, and the farther the sheet is from the electrodes, the higher the shrinkage rate becomes.

Therefore, the contraction near the center line is greater than that near the electrodes on both sides, which causes a problem in that a wavy shape distortion as shown in FIG. 1 occurs on both sides of the heating element.

This project was developed in view of the above circumstances, and by providing a cut of an appropriate length between both electrodes, the generation of the tensile force that causes the wave-like distortion is eliminated, and the surface in which the metal electrode wire is embedded is removed. The shaped heating element was made possible by extrusion molding.

The planar heating element sheet according to the present application will be explained in detail below. Its structure is such that a molten synthetic resin mixed with conductive fillers such as carbon black and graphite powder is integrated with flat knitted metal wires for electrodes arranged on both sides. In the planar heating element sheet to be extruded and molded, after extruding the molten synthetic resin mixed with a conductive filler together with the flat-knit metal wires 1, 1 for electrodes on both sides, the flat-knit metal wires for electrodes are It is characterized in that lines or broken line-shaped cuts 2 are provided at short intervals between the lines, the length being approximately the same as that between the electrode flat-knit metal wires 1, 1.

2 and 3 of the drawings show a preferred embodiment of the present invention. FIG. 2 is a perspective view of a heating element sheet 10 with cuts to remove wavy distortion, and FIG. 3 is a perspective view of the heating element A planar heating element is shown in which a sheet is cut to an appropriate length, a cutout 3 is provided in the sheet leaving a plain knitted metal wire portion, and an insulating coating is integrally applied to both upper and lower surfaces and side edges of the sheet 10. .

The wavelength (pitch) of the waveform distortion shown in Figure 1 is
Since it varies depending on the manufacturing process, especially the set temperature of the cooling roll, the number of cooling rolls, etc., the interval and number of cuts 2, etc. are determined by taking into consideration the state of distortion and the mechanical strength of the heat generating sheet.

Further, the cuts 2 and the like are made inside the metal wires 1 for electrodes on both sides of the heating element sheet without reaching them.

The configuration of the planar heating element sheet according to the present invention is as described above, and the following specific effects are produced from the configuration.

That is, in this case, since the notches 2 are provided between the electrodes of the heating element sheet 10, the tensile force (generated from the difference in internal shrinkage rate of the heating element sheet) in the direction between the electrodes, which is the cause of wavy distortion, is dispersed, and as shown in FIG. It is formed as a flat heating element sheet such as.

As a result, the radiation from the surface of the heating element sheet becomes uniform, so that the elongation of the sheet that occurs during heat generation also becomes uniform.

In order to put this idea into practical use as a surface heating element, the third
As shown in the diagram, insulating synthetic resin is often melted to a specified thickness and coated on the front and back of the sheet body, or insulating synthetic resin sheets are laminated with adhesive on the front and back of the main body sheet, but even in this case heat generation occurs. Since the deformation of the body sheet is uniform, such a planar heating element also becomes a flat plate and can generate heat uniformly.

[Brief explanation of the drawing]

Figure 1 shows the state of the heating element sheet with wavy distortion, Figure 2 shows the heating element sheet of the present invention with cuts removed to remove the wavy distortion, and Figure 3 shows the surface covered with insulation. FIG. 3 is a perspective view of a shaped heating element. 10... Planar heating element sheet, 1... Plain knitted metal wire for electrode, 2... Notch.

Claims (1)

[Scope of utility model registration request] A conductive filling is used in a planar heating element sheet that is formed by extruding a molten synthetic resin mixed with conductive fillers such as carbon black and graphite powder together with flat metal wires for electrodes arranged on both sides. After extruding the molten synthetic resin mixed with the material together with the flat-knit metal wires 1, 1 for electrodes on both sides, a layer of approximately the same length as between the flat-knit metal wires 1, 1 for electrodes is placed between the flat-knit metal wires 1, 1 for electrodes. A planar heating element sheet having length line or broken line notches 2 provided at short intervals.