JPH0116307Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a planar heating element having a flexible charged electrode that has high strength against bending.

(Prior art) A planar heat-generating conductor is closely attached to the entire surface of a sheet-shaped base material, or strip-shaped conductors are arranged in multiple rows and columns and attached, and a flexible electrostatically attached material is attached to the end of the sheet-shaped base material. There has been a planar heating element made of
An example is disclosed in Japanese Utility Model Application Publication No. 55-161386, and the structure of the charging electrode used is as shown in FIG. is attached to the planar heating conductor 3, and a protective sheet 7 made of nonwoven fabric or the like is placed on the surface of the sheet heating conductor 3.
In many cases, the pieces are pasted together and then sewn using a sewing machine9.

(Problems to be Solved by the Invention) As mentioned above, the material in which the flexible protective sheet 7 is bonded to the surface of the metal foil 5 is highly flexible, so it can be easily folded when used for carpets, etc. It is easy to use and has the advantage of not causing a "stiff" and strange feeling, but on the other hand, it has poor bending strength and does not meet the Japanese Industrial Standards (JIS P).
8115-1976) was used to test the bending strength at a corner with a radius of curvature of 0.5 mm (width 20 mm).
The test was carried out under the condition that the charged electrode of mm was applied with a load of 1 kg), and after 50 cycles, the first cut leading to cutting occurred at the edge of the metal foil 5.

This poor bending strength is due to the fact that the charging electrode breaks during use, resulting in a part of the sheet heating conductor not being energized, which inevitably reduces the reliability of the product. Nakatsuta.

Therefore, the present invention provides a planar heating element with a charging electrode of a new structure that can dramatically increase folding strength while having the same flexibility as the conventional charging electrode described above. The aim is to extend life and improve reliability.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a strip-shaped metal foil 5 having conductivity, and a strip-shaped metal foil 5 that is made of metal foil 5 along the entire one side and both longitudinal edges of the opposite side. A flexible charging electrode 4 is formed by an insulating layer 6 made of a hard or semi-hard synthetic resin film bonded via a curable adhesive 8, and this charging electrode 4 is bonded to a metal foil 5.
is attached to the edge of the sheet heating element 1 so that the exposed surface thereof is in contact with the conductive end of the sheet heating element 1, and the intermediate exposed surface of the metal foil 5 and the conductive end of the sheet heating element 1 are The overlapping portion is sewn with at least two threads running in the longitudinal direction of the charged electrode 4 to form a planar heating element.

The insulating layer 6 may include a film made of polyethylene terephthalate resin,
On the other hand, the protective sheet 7 may be a thin sheet of non-woven fabric or the like.

(Function) In the present invention, the metal foil 5 of the charging electrode 4 is reinforced by sandwiching the longitudinal edges of the metal foil 5 from both sides with an insulating layer 6 made of synthetic resin film, like a border, so that the bending resistance is increased. Since the metal foil 5 is large, it is possible to suppress the occurrence of cuts from the edges over a long period of time, and the exposed surface of the metal foil 5 can be attached to the conductive end of the planar heating element 1 with a sewing thread. Therefore, the contact resistance at the connection portion can be made as small as possible to prevent local heat generation, and stable current conduction can be achieved.

(Example) In FIGS. 1 and 2, numeral 1 denotes a planar heating element in which a band-shaped sheet heating conductor 3 is spread in the weft direction in a sheet base material 2, and the pitch is adjusted appropriately. Charging electrodes 4 are attached to both edges of the sheet base material 2 in contact with the ends of each of the planar heating conductors 3. There are 9 stitches required.

The planar heat-generating conductor 3 is formed integrally with the structure of the sheet base material 2 by using conductive threads as part of the wefts of the sheet base material 2 and weaving them in the horizontal striped shape shown in the figure. It is also made of conductive fluororesin.
A sheet with a thickness of about 0.1 mm is cut into strips and pasted on the sheet base material 2, or the sheet is not cut into strips but is formed into a sheet having approximately the same shape as the sheet base material 2, and this is then cut into strips and attached to the sheet base material 2. Various structures are available, such as those attached to the surface.

On the other hand, the charged electrode 4 has a strip-shaped metal foil 5 having conductivity such as copper foil as a conductive part, and an insulating layer 6 and a protective sheet 7 are successively laminated on the outer surface of the strip-shaped metal foil 5 to form a flexible strip as a whole. are doing.

The metal foil 5 is, for example, a copper foil with a thickness of 30 μm and a width of 20 mm, while the insulating layer 6 is made of a hard or semi-hard synthetic resin film, such as a polyethylene terephthalate resin film with a thickness of about 25 μm. It is placed along the entire surface of one side of the metal foil 5, and then bent to the opposite side, and is brought into close contact with both longitudinal edges of the metal foil 5 with a width of about 4 mm to form a border.

This insulating layer 6 is bonded to the metal foil 5 with a curable adhesive 8. For example, the curable adhesive 8 containing a solvent is applied to one side of a synthetic resin film having a predetermined width, and the solvent is evaporated. After drying, the insulating layer 6 is tightly bonded to the metal foil 5 and heat-compression bonded to the metal foil 5, whereby the insulating layer 6 is strongly bonded to the metal foil 5 by curing of the adhesive 8.

Next, the protective sheet 7 is made by adhering a non-woven fabric having the same width as the metal foil 5 or slightly wider and having a weight of 30 g/m ² to the surface of the insulating layer 6 which is adhered to one side of the metal foil 5 with an adhesive. There is.

The charged electrode 4 having a multilayer structure is arranged so that the exposed intermediate surface of the metal foil 5 having a width of about 12 mm can directly touch the end of the planar heating conductor 3. At the same time, the portion where the exposed surface of the metal foil 5 and the planar heating conductor 3 overlap is sewn with at least two threads running in the longitudinal direction of the charged electrode 4, as shown in Figure 1. 9, the planar heating element 1 is completed.

Note that, in addition to sewing two charging electrodes 4 to the conductive end of the planar heating element 1 so as to sandwich them from both sides as shown in the example, one charging electrode 4 may be attached only to one side. The stitching 9 may be performed using the sewing machine.

In the planar heating element 1 having the above configuration, the charged electrode 4 covers both longitudinal edges of the metal foil 5 with an insulating layer 6 and is bonded together with a curable adhesive 8. Therefore, both edges have high bending strength and are sufficiently flexible, so that the metal foil 5 is difficult to break even when folded frequently, and does not have a "stiff" feel.

Note that the charging electrode 4 manufactured with the same structure as the above example
was subjected to a bending strength test under a corner with a radius of curvature of 0.5 mm under a 1 kg load using an MIT type tester conforming to the Japanese Industrial Standards, and the middle part of the metal foil 5 was exposed after about 1000 times There is a slight cut in the part,
Both longitudinal edges remained intact.

This means that even if the charged electrode 4 is bent frequently,
It is clear that the metal foil 5 can still be used as an electrode without breaking.

(Effect of the invention) As explained above, the present invention has the metal foil 5 of the charged electrode 4 reinforced by the insulating layer 6 on both longitudinal edges thereof in a border-like manner, and furthermore, the metal foil 5 and the insulating layer Since the metal foil 5 and the metal foil 5 are firmly bonded with a curable adhesive to prevent mutual slippage, the strength of the metal foil 5 against bending is increased and stable conductive performance can be exhibited for a long period of time.

In addition, since the exposed intermediate surface of the metal foil 5 and the conductive end of the planar heating element 1 are sewn together in the longitudinal direction with at least two threads, the electrical resistance of the contact portion is kept low and local heat generation is achieved. This has the effect of making the planar heating element perform stable heating.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view of a planar heating element according to an example of the present invention, FIG. 2 is a cross-sectional view taken along the - line in FIG. 1, and FIG. 3 is an enlarged view of the charging electrode portion in FIG. 2. , FIG. 4 is a partially enlarged sectional view of a conventional sheet heating element. DESCRIPTION OF SYMBOLS 1... Planar heating element, 4... Charging electrode, 5... Metal foil, 6... Insulating layer, 7... Protective sheet, 8... Curing adhesive.

Claims (1)

[Scope of utility model registration request] Consists of a conductive strip-shaped metal foil 5 and a hard or semi-hard synthetic resin film adhered via a curable adhesive 8 along the entire one side of the metal foil 5 and along both longitudinal edges of the opposite side. A flexible charging electrode 4 is formed with the insulating layer 6, and the charging electrode 4
is attached to the edge of the sheet heating element 1 so that the exposed intermediate surface of the metal foil 5 is in contact with the conductive end of the sheet heating element 1, and the exposed surface of the metal foil 5 and the sheet heating element 1
A planar heating element characterized in that the portion where the conductive end portion of the charged electrode 4 overlaps is sewn with at least two threads running in the longitudinal direction of the charged electrode 4.