JP2001110552A - Foldable flat heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer a foldable sheet type heater whose transportation is convenient, operation in the field is very easy, heating a wide area to a uniform temperature, and thus enabling the heater to have excellent flexibility, water resistance, and electric insulation, as well as good processing and workability to the final products, and stability for a long term use. SOLUTION: The foldable flat heater is formed by adhering with the sheet type and foldable heat conductive adhering part to the PTC electric conductive sheet heater unit substrates having plural electrodes. The distance between electrodes adjacent to the heat conductive adhering part of the sheet heater unit substrates, is set shorter than the other distance between electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foldable sheet heating element, and more particularly, to a foldable sheet heating element which is convenient for transportation.
And it is possible to heat a wide area uniformly.
Furthermore, the present invention relates to a foldable sheet heating element having excellent long-term use stability.

[0002]

2. Description of the Related Art Hitherto, as a planar heating element, a resistance heating element having no self-temperature controllability (PTC characteristic) in a low temperature range of about 100 ° C. or less, for example, a heating element using a nichrome wire has been widely used. . However, these fatal defects have a risk that the temperature will rise to a region that is undesirably high for practical or safety reasons, and a complicated overheating prevention mechanism is required. It is also known to form a conductive resin having PTC characteristics on, for example, a fiber cloth and use this as a planar heating element. However, these fatal flaws lack stability and are not reliable, in particular, they cannot escape changes over time after long-term use, and they have poor workability. That place great restrictions on

Heretofore, there has not been proposed a sheet heating element having PTC characteristics, which is convenient for transportation, simple in construction, and can uniformly heat a large area.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to heat a large area to a uniform temperature, which is convenient for transportation, extremely easy to construct on site, and furthermore, An object of the present invention is to provide a foldable sheet heating element which is excellent in flexibility, water resistance and electric insulation, has good workability and workability into a final product, and has excellent long-term use stability.

[0005]

As a result of intensive studies by the present inventors, the above-mentioned object of the present invention has been industrially advantageously achieved by the present invention having the following constitution.

[1] A PTC conductive planar heat generating unit substrate having a plurality of electrodes is joined by a sheet-shaped foldable thermally conductive joining member, and the heat of the planar heat generating unit substrate is A foldable planar heating element characterized in that the distance between electrodes adjacent to the conductive bonding member is shorter than the distance between other electrodes.

[2] The PTC conductive planar heating unit substrate having a plurality of electrodes is rectangular, and the electrodes are provided in parallel with one side of the square. A foldable planar heating element.

[3] A PTC conductive sheet heating unit substrate having a plurality of electrodes is joined by a sheet-shaped foldable heat conducting joining member so that all the electrodes are parallel. The foldable planar heating element according to the above [2], which is characterized in that:

[4] The method according to any one of [1] to [3] above, wherein the PTC conductive planar heating unit substrate is obtained by impregnating or applying a conductive paint to a fiber cloth. A foldable planar heating element.

[5] The above-mentioned [4], wherein the PTC conductive planar heating unit substrate is formed by impregnating or applying a conductive paint on a fiber cloth and forming a flexible resin layer on the surface thereof. ] The foldable sheet heating element described in the above.

[6] The flexible resin layer is made of a styrene-butadiene-styrene copolymer, a styrene-isoprene-styrene copolymer, a styrene-ethylene-butylene-styrene copolymer, or a styrene-ethylene-propylene-styrene copolymer. Coalesce, hydrogenated styrene-butadiene random copolymer, polyolefin-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, 1,2-polybutadiene-based thermoplastic elastomer,
Consists of ethylene-vinyl acetate thermoplastic elastomer, polyvinyl chloride thermoplastic elastomer, natural rubber thermoplastic elastomer, fluoro rubber thermoplastic elastomer, trans-polyisoprene thermoplastic elastomer, and chlorinated polyethylene thermoplastic elastomer The foldable planar heating element according to the above [5], comprising a thermoplastic elastomer selected from the group.

[7] The foldable sheet heating element according to the above [5], wherein the flexible resin layer is formed by curing rubber latex.

The most significant feature of the present invention is that a large area can be covered by joining a PTC conductive sheet heating unit base material having a plurality of electrodes with a sheet-shaped foldable heat conductive joining member. Not only can the planar heating element be easily transported, but also the distance between the electrodes adjacent to the heat conductive bonding member of the planar heating unit substrate is shorter than the distance between the other electrodes. Thus, the temperature of the entire planar heating element is set to be substantially uniform. Further, a rubber latex such as SBR or NBR is applied to the surface of the PTC conductive planar heating unit base material,
Then, by cross-linking or forming a thermoplastic elastomer layer, it is excellent in flexibility, water resistance and electric insulation, good in workability and workability to the final product, and excellent in long-term use stability. That is, a flat heating element was provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the PTC conductive sheet heating unit substrate is not particularly limited, and any conventionally known one can be used. Impregnated into a fabric, for example a woven fabric, dried,
What was manufactured through a heating process is used. It is preferable to use a fiber cloth that contains a conductive wire in advance.
As such a fiber cloth, cotton, polyester fiber, polyamide fiber, acrylic fiber, vinylon fiber, etc.
Or a spun yarn containing at least one of these, or a fiber yarn made of a mixed fiber yarn or the like is arranged on a warp and / or a weft,
A fiber woven fabric in which a copper wire or a good conductive filament in place of the copper wire is arranged at a predetermined interval on a part of the warp and / or the weft is used. As the heating method, for example, far-infrared irradiation, microwave irradiation, dielectric heating and the like can be used. However, the heating method is not limited thereto, and any method capable of appropriately controlling the temperature may be used. It is preferable to use a method in which the divergence rate of the solvent cannot be different between the surface and the inside of the coating film.

As the PTC conductive coating used at this time, those described in US Pat. No. 5,556,576 are typically used. That is, the conductive paint is manufactured by the following sequence of steps. (1) An aromatic solvent is placed in a heated stirring vessel and heated to a temperature of 40 to 60 ° C. (2) A substrate forming substance selected from a thermoplastic resin, an uncured thermosetting resin and an elastomer is added in an amount of 25 to 40% by weight of the conductive substance in a later step. (3) 25 to 40% by weight of the conductive powder to be added
Of paraffin and stirring is continued until all solids are dissolved. (4) Add conductive fine powder selected from graphite, carbon black, metal powder and the like, and stir until a smooth paste is formed. (5) Kneading the paste until a substantially uniform dispersion of the conductive fine powder is obtained.

As the PTC conductive planar heating unit substrate, a material obtained by impregnating a yarn with a conductive paint can also be used.
The yarn is impregnated with a conductive paint to spin the yarn to which PTC conductivity has been imparted, and the resulting yarn is used as a face cloth. In this case, any material can be selected for the conductive wire used for the electrode, and the material can be inserted into an arbitrary shape at the time of spinning. Further, when a voltage is applied in the direction of the weft yarn of the sheet heating element, almost no voltage is applied to the warp yarn, and the heat generation function is not exhibited. In this case, using a yarn impregnated with conductive paint on the face cloth and spinning in combination with a yarn not impregnated with conductive paint, only the yarn in the direction to which voltage is applied can be given a heat generating function. Thus, paint can be saved. In this case, the strength of the heating element can be enhanced by using a cable in which a fiber having high tensile strength such as nylon is twisted with the yarn impregnated with the conductive paint.

In the present invention, a PT having a plurality of electrodes
It is preferable that the C-conductive planar heat generating unit substrate is rectangular, and the electrode is provided in parallel to one side of the square. Then, it is preferable that the PTC conductive sheet heating unit base material is joined by a sheet-shaped foldable heat conducting joining member so that all electrodes are parallel. The size of the PTC conductive sheet heating unit substrate having a plurality of electrodes is arbitrary depending on the purpose of use of the sheet heating element. For example, if it is for heating an 8-tatami flooring, About 235mm-250mm, length 2
It is preferably about 650 mm. In this case, the width of the joining member is preferably about 53 mm.

In the present invention, the PTC conductive planar heating unit substrate has a plurality of electrodes. When the PTC conductive planar heat generating unit base materials are joined together, if the distance between these electrodes is made uniform, the temperature of the heat conductive joining member that can be folded in a sheet shape is lower than that of the other portions. As a result, it is impossible to obtain a planar heating element having a wide area with a uniform temperature as a whole. Therefore, in the present invention, it is important that the distance between the electrodes adjacent to the heat conductive bonding member of the planar heating unit substrate is shorter than the distance between the other electrodes. As a result, it is possible to easily obtain a planar heating element having a large area with a uniform temperature.
In other words, the electrical resistance in the narrow part between the electrodes becomes smaller,
Although the heat generation temperature is increased, the increased temperature is conducted to the portion of the heat conductive joining member, whereby a planar heating element having a large area and a uniform temperature as a whole can be obtained.

The length of the inter-electrode distance between the electrodes adjacent to the heat conductive bonding member of the base heat generating unit depends on the characteristics and size of the heat conductive bonding member. Although it depends on the properties of the substrate, it can be easily determined by experiment.

In the present invention, the joining member to be used is not particularly limited as long as it can be folded in a sheet shape and is thermally conductive. Typically, aluminum tape is preferably used, but one obtained by laminating metal on a flexible plastic sheet can be used. The joining member preferably has an adhesive or an adhesive on one surface thereof.

In the present invention, it is preferable to form a flexible resin layer on the surface of the PTC conductive planar heating unit substrate. This imparts properties such as flexibility, water resistance and electrical insulation to the sheet heating element, and imparts good workability and workability to the final product and excellent long-term use stability. As one method for forming the flexible resin layer, there is a method in which a thermoplastic elastomer sheet is superimposed on the surface of the PTC conductive planar heating unit base material and thermocompression-bonded. At this time, a suitable adhesive, preferably a heat-sealing adhesive may be used. As such thermoplastic elastomer, styrene-butadiene-styrene copolymer,
Styrene-isoprene-styrene copolymer, styrene-
Ethylene / butylene / styrene copolymer, styrene / ethylene / propylene / styrene copolymer, hydrogenated styrene / butadiene random copolymer, polyolefin-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide -Based thermoplastic elastomer, 1,2-polybutadiene-based thermoplastic elastomer, ethylene-vinyl acetate-based thermoplastic elastomer, polyvinyl chloride-based thermoplastic elastomer, natural rubber-based thermoplastic elastomer, fluoro rubber-based thermoplastic elastomer, trans-polyisoprene Thermoplastic elastomers, and chlorinated polyethylene thermoplastic elastomers.

As another method for forming a flexible resin layer, there is a method in which a rubber latex is applied to the surface of a PTC conductive sheet-like heat generating unit base material and the rubber latex is cured. Examples of such rubber latex include natural rubber latex, isoprene rubber latex, butadiene rubber latex, styrene-butadiene rubber latex, carboxy-modified styrene-butadiene rubber latex, styrene-butadiene-vinylpyridine-based latex, acrylonitrile-butadiene rubber latex, chloroprene latex, An acrylic emulsion, an acrylate-butadiene rubber latex, a vinyl acetate emulsion, and the like can be given.

FIG. 2 shows an example in which the foldable sheet heating element of the present invention is applied to a flooring as a surface material. FIG. 2 is a three-dimensional view, and FIG. 1 is a plan view of the sheet heating element according to the present invention used in FIG. Each code is as follows. That is, 1: panel, 2: stitched plywood, 3:
Jota, 4: Aluminum tape as a heat conductive joining member
5: a heat insulating material, and 6: a planar heating element. The surface material is fixed to the joist through the small joist. Usually, they are fixed by nailing. Therefore, a heating element cannot be laid on the joist. Therefore, this joist does not get warm because the heat is not transmitted. Therefore, in the present invention, an aluminum tape is provided as a heat conductive joint member on the small joist to conduct heat. However, a normal planar heating element having the same electrode-to-electrode distance has a defect that the temperature of the portion of the heating element adjacent to the heat conductive bonding member is lower than that of the other portions. Therefore, in the present invention, as shown in FIGS. 1 and 2, this defect is solved by shortening the distance between the electrodes of the heating element adjacent to the heat conductive bonding member. In FIG, L ₁ is longer distance between the electrodes, L ₂ is shorter distance between the electrodes. Thus, the difference between the electrodes is provided. Further, L ₃ is the width of the heat conductive bonding member, L ₄ is a vertical length of the planar heating element.

The planar heating element obtained according to the present invention is foldable and therefore convenient for transportation, extremely easy to construct on site, and heats a large area to a uniform temperature. It has excellent flexibility, water resistance and electrical insulation, good workability and workability to the final product, and excellent long-term use stability. Is extremely useful as a unit member.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 3.5 kg of graphite (SP-20, manufactured by Nippon Graphite Co., Ltd.) and 1.5 kg of acetylene black (Denka Black, manufactured by Denki Kagaku Co., Ltd.) were mixed with an ethylene / propylene / styrene copolymer (manufactured by Shell Co., Ltd.). Kraton G1701) 5 kg, polystyrene 1
kg, paraffin 4 kg, and MEK / xylene = 20
The mixture was added to a solution consisting of 15 kg of a / 80 mixed solvent to form a uniform paste, which was then diluted with 1.5 times the amount of xylene to prepare a coating liquid containing a heating material.

On the other hand, in a polyester / cotton blended yarn (20/2 m count) warped at an interval of about 1 mm, as a good conductive filament, a polyester filament yarn of 275 dtex / f has a width of about 0.3 mm on the surface. Five covering yarns wound with copper foil are aligned, and five electrodes are arranged at intervals of about 25 cm. A polyester / cotton blended yarn (20/2 m count) is used as the weft and driven at intervals of about 1 mm. About 5 width
A 0-cm coarse woven fabric was formed, and the obtained woven fabric was immersed in the coating solution, squeezed lightly with a roll, and then dried by heating. Thus, a PTC conductive substrate having a planar heating function was obtained.

A butylene terephthalate block copolymer sheet was laminated on both sides of the PTC conductive base material having a planar heating function via a polyethylene terephthalate copolymer film, and thermocompression-bonded. The obtained sheet heating element is an extremely flexible sheet-like material having a thickness of 0.6 mm, and its electrical characteristics such as electric resistance are almost the same as those of the PTC conductive substrate having the sheet heating function. Did not. Moreover, it was excellent in form stability and had high strength. Each dimension from the planar heating element thus obtained,
L ₁ : 65 mm, L ₂ : 50 mm, L ₃ : 150 mm,
And L _4: a 300 mm, were prepared such bonded planar heating element shown in Figure 1. Then, a floor material with a built-in planar heating element shown in FIG. 2 was produced using the joined planar heating element. The panel thickness is 12 mm, the plywood thickness is 12 mm, the small joist dimension is 45 mm × 50 mm, and the heat insulating material is polyurethane foam. A current of 100 V was applied to the floor material with the built-in planar heating element, and after 24 minutes, the temperatures at points P ₁ , P ₂ , and P ₃ in FIG. 2 were measured.
As a result, P ₁ : 37.0 ° C. and P ₂ : 36.1, respectively.
℃, and P ₃ : 37.9 ℃, was almost uniform temperature. That is, the maximum temperature difference was the temperature difference 1.8 ° C. between the point _{P 2} and the point _{P 3.}

Comparative Example 1 Each of the dimensions of the sheet heating element obtained in Example 1 was L ₁ : 57.5 mm in FIG.
_{2: 57.5mm, L 3: 150mm} , and _L 4: 30
A bonded planar heating element measuring 0 mm was prepared. Then, a floor material having a built-in planar heating element having the same structure as that shown in FIG. 2 was produced using the joined planar heating element. The panel thickness was 12 mm, the plywood thickness was 12 mm, the small joist dimension was 45 mm × 50 mm, and the heat insulating material was a polyurethane foam. A current of 100 V was applied to the floor material with the built-in planar heating element, and after 30 minutes, the temperatures at points P ₁ , P ₂ , and P ₃ in FIG. 2 were measured. As a result, P ₁ : 26.2 ° C. and P ₂ : 2 respectively
9.4 ° C. and P ₃ : 37.5 ° C., the points P ₁ and P
_3. There was a large temperature difference of 11.3 ° C. with ₃ .

[0030]

According to the present invention, on-site construction is extremely easy, and it is possible to heat a large area to a uniform temperature, and it is excellent in flexibility, water resistance, electric insulation and the like. In addition, a foldable sheet heating element excellent in workability and workability to a final product and excellent in long-term use stability is industrially extremely advantageously provided. Such a planar heating element can be used for various purposes, and is preferably used for, for example, a flooring having a heating function, a floor tile having a heating function, and the like.

[Brief description of the drawings]

FIG. 1 is a plan view of a sheet heating element according to the present invention.

FIG. 2 is a three-dimensional view of a floor material using the sheet heating element according to the present invention.

[Explanation of symbols]

1: Panel 2: stearyl-clad plate 3: Small joists 4: aluminum tape as a heat conductive bonding member 5: the heat insulating material 6: the planar heating element 7: electrode L _1: between longer electrode distance L _2: the shorter L ₃ : Width of heat conductive joining member L ₄ : Vertical length of sheet heating element

Claims (7)

[Claims] 1. A PTC conductive sheet-like heat generating unit base material having a plurality of electrodes is joined by a sheet-shaped foldable heat-conductive joining member, and said sheet-like heat generation unit base material has a heat conduction. A foldable planar heating element characterized in that the distance between electrodes adjacent to the sexual bonding member is shorter than the distance between other electrodes. 2. The foldable unit according to claim 1, wherein the PTC conductive planar heating unit substrate having a plurality of electrodes is rectangular, and the electrodes are provided parallel to one side of the square. Sheet heating element. 3. A PTC conductive planar heat generating unit base material having a plurality of electrodes is bonded by a sheet-shaped foldable heat conductive bonding member so that all the electrodes are parallel. The foldable planar heating element according to claim 2, wherein 4. The foldable surface according to claim 1, wherein the PTC conductive planar heating unit substrate is obtained by impregnating or applying a conductive paint to a fiber cloth. Heating element. 5. A PTC conductive sheet-like heat generating unit substrate comprising a fibrous fabric impregnated or coated with a conductive coating material and a flexible resin layer formed on the surface thereof. Foldable sheet heating element. 6. A flexible resin layer comprising styrene-butadiene-
Styrene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, hydrogenated styrene-butadiene random copolymer, polyolefin-based heat Thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer,
1,2-polybutadiene-based thermoplastic elastomer, ethylene-vinyl acetate-based thermoplastic elastomer, polyvinyl chloride-based thermoplastic elastomer, natural rubber-based thermoplastic elastomer, fluororubber-based thermoplastic elastomer, trans-polyisoprene-based thermoplastic elastomer, 6. The foldable sheet heating element according to claim 5, comprising a thermoplastic elastomer selected from the group consisting of chlorinated polyethylene thermoplastic elastomers. 7. The foldable sheet heating element according to claim 5, wherein the flexible resin layer is formed by curing rubber latex.