JPH09199263A - Heating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating material which eliminates changing of a heating resistor resistance value and breaking even by repeated compression in a pavement road and has heating efficiency equivalent to a surface type heating material even despite a linear heating resistor. SOLUTION: A heating resistor 1 serves as a core material, in its periphery, a fiber 2 of small break elongation and large break strength is arranged, simultaneous resin coating with the heating resistor 1 is performed, so as to enhance adhesiveness between the heating resistor 1 and the fiber 2 arranged in the periphery, by the fiber obtaining the break elongation of that or less of the heating resistor 1, it is designed so as to generate breaking of the arranged fiber 2 before breaking the heating resistor 1. Metal oxide powder 6 is mixed in a coating resin, metal foil 5 is fixed to a heating material bottom part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat generating material, and more particularly to a heat generating material having a strength suitable for snow melting road heating and the like.

[0002]

2. Description of the Related Art Conventionally, electric road heating, groundwater, and hot water circulation heat pipe systems have been adopted in snowy and cold regions. Among them, electric load heating materials include nichrome wire heating material, carbon heating material,
Heat-generating materials made by twisting stainless discontinuous fibers and aramid discontinuous fibers have been used, but both heat-generating materials have a nichrome wire heat-generating material and carbon heat-generating material due to the deformation of road roadbed and asphalt base layer surface layers due to depression and flow. The heat-generating material obtained by twisting the discontinuous stainless steel fibers and the discontinuous aramid fibers has a drawback that the resistance value changes greatly.

The nichrome wire pressure resistant type for load heating has a three-layer resin coating structure, and furthermore, by providing an air layer having a gear cross-sectional shape on the second layer, compression load distribution and core material protection are performed. There is. However, there is a drawback that the roadbed, the asphalt base layer, and the surface layer are likely to be broken due to deformation due to depression and flow.

The carbon compound heat-generating material for load heating has a large volume specific resistance value, so that the wire diameter must be increased in order to lower the resistance value. In particular, it has a drawback that it is inferior in durability against bending stress and easily breaks.

The heat-generating material obtained by twisting the stainless discontinuous fiber and the aramid discontinuous fiber has a drawback that the wire resistance is unlikely to occur but the electric resistance value fluctuates due to repeated compressive strain when the yarn fineness is increased.

Each of the heat-generating materials has a round cross-sectional shape which makes it difficult for asphalt to be sufficiently filled.
It has a drawback that the deformation rate of the heat generating material becomes large. The extension direction depends only on the heat generating material and the covering material, and the strength depends on the heat generating resistor and the covering material. However, the strength of the heating resistor and the strength of the insulating coating resin alone cannot withstand the repeated load on the road, resulting in the rupture of the heating resistor and the change in resistance value.

The buried object in the pavement must have strength and low elongation. However, the conventional exothermic material has a round cross-sectional shape and the strength in the extending direction depends on the heating element and the coating resin, and therefore the tensile strength is small and the tensile elongation is large. In addition, since the asphalt aggregate is not sufficiently filled in the bottom of the wire during the asphalt pavement construction to create a gap and the road strength cannot be maintained, the strength of the heat generating resistor cannot be maintained due to the asphalt flow and depression.

[0008] Asphalt pavement is usually machined by an asphalt finisher, but when a heat generating material is buried, a shearing stress, a torsional moment, and a bending moment are applied to the heat generating material due to the compressive load applied on the asphalt finisher. For this reason, at present, only construction is performed manually so that the heat-generating material does not break.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-generating material in which the above-mentioned drawbacks are ameliorated and the resistance of the heat-generating resistor does not change even after repeated compression and the heat-generating resistor does not break. . Another object of the present invention is to provide a heat-generating material having the same heat-generating efficiency as that of the sheet-shaped heat-generating material despite the linear heat-generating resistor. Another object of the present invention is to provide a heat-generating material that can be machined by mounting on an asphalt finisher.

[0010]

In order to achieve the object of the invention as described above, a heating resistor is used as a core material, and fibers having a lower breaking elongation and a higher breaking strength than the heating resistor are arranged around the core member. By coating the heating resistor with the resin at the same time to improve the adhesion between the heating resistor and the fibers arranged in the surroundings, the heating resistor is ruptured by the arrayed fiber that obtains a breaking elongation less than the breaking elongation of the heating resistor. It was designed so that the breakage of the array fiber occurred before. The cross-sectional shape of the exothermic material was a flat plate-shaped square cross section. The flat rectangular cross section is effective in preventing road deformation due to compressive load on the road and also provides good adhesion to the asphalt base layer.

As the fibers to be arranged, fibers having a breaking elongation of 0.5% or more and 20% or less, preferably 0.5% or more and 5.0% or less and a breaking strength of 6 g / de or more and 100 g / de or less are used. . This is because the array fiber absorbs the compressive load applied to the heating resistor if the elongation at break is small in comparison with the heating resistor. Arranged fibers that can be used include aramid fibers, arylate fibers, high-strength polyethylene fibers, polyester fibers, nylon fibers, glass fibers, and carbon fibers.

The fact that the breaking elongation of the arrayed fibers in the above-mentioned relative comparison with the heating resistor is small means that the breaking elongation of the stainless fiber is 20% or more when a nichrome wire is used as the heating resistor. Therefore, an array fiber having a breaking elongation of 20% or less is used. Since the breaking elongation of the polyester fiber is 8%, it can be used. When stainless fiber or stainless wire is used as the heating resistor, the breaking elongation of the stainless fiber is 1.7% to 2.8% and the breaking elongation of the stainless wire is 3.6%. Aligned fibers with a degree of elongation or less are used. An aramid fiber having a breaking elongation of 1.5% or a carbon fiber having a breaking elongation of 0.5% to 2.0% can be used.

The present invention will be described below with reference to the accompanying drawings. 1, 2, and 3 are perspective views showing an embodiment of the heat generating material of the present invention.

The insulating coating is performed by simultaneously resin-coating 1 to 100 bundles of independent thread strands. The heating material width can be set freely from 2.0 mm to 200 mm, and the heating material thickness can be freely set from 2.0 mm to 20 mm including the yarn strand thickness. Further, the insulating resin coating on each strand can be extruded in a separated and independent state (FIG. 2) by changing the extruder die and nipple shape.

The insulating resin coating is for preventing current leakage to the outside of the heating resistor, and may be any material such as non-conductive plastic material and rubber material.

When strength is required, the fineness of the array fibers of each yarn strand may be increased.

The heat generating material of the present invention can be designed to have high heat generating material strength by increasing the yarn fineness of the yarn strand bundle,
Since the compressive load is absorbed by the arrayed fibers as a whole, the thickness of the insulating coating resin can be reduced. Therefore, it is possible to further reduce the thickness of the heat generating material as a whole, and it is possible to prevent a decrease in road strength due to the laying of the heat generating material as much as possible. By reducing the coating thickness, the amount of heat taken by the coating resin can be reduced and the heat generation efficiency can be improved.

As the heating resistor, it is preferable to use a linear resistor made of nichrome wire, stainless fiber or stainless wire.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION When the heat generating material of the present invention is used, for example, as a road heating material for snow melting, the arranged fibers have a small breaking elongation and a large breaking strength, so that the asphalt base layer and the surface layer do not sink or flow. Even if the heating resistor is not easily broken, it has excellent adhesion to the asphalt base layer surface when using a plate-shaped square cross-section heating material, and asphalt finishers can be machine-installed to prevent the formation of asphalt voids. Can hold.
Furthermore, when the heat generating material of Example 5 is used, heat is evenly transferred to the road surface.

[0020]

The present invention will now be described in detail with reference to examples.

[0021]

[Example 1] 100 stainless fibers (single yarn denier 8.35 de) were used as the heating resistor 1 for all yarn strands, and polyparaphenylene terephthalamide continuous filaments (Kevlar 149 single yarn denier 1.42 de manufactured by DuPont Toray Kevlar KK) were used. ) 8000 fibers were used as array fiber 2.
An insulating resin coating 3 made of high-density polyethylene resin was applied while bundling and aligning the heating resistors 1 and the array fibers 2 to obtain a heating material 4 (FIG. 1) having 21 bundles of yarn strands, a thickness of 2.5 mm, and a width of 55 mm.

[0022]

[Embodiment 2] Three bundles of yarn strands are used as a heat-generating material by changing dies and nipples, and 900 strands of stainless fiber (single yarn denier 8.35 de) are used as the heat-generating resistor 1 for the yarn strands, and polyparaphenylene terephthalamide continuous Long fiber (Devon Toray Kevlar Kevlar 1
8000 single-fiber denier 1.42 de) 8000 fibers were used as the array fiber 2. The heat generating resistor 1 and the array fiber 2 are bundled and aligned on the central position strand, and the remaining strand is polyparaphenylene terephthalamide continuous long fiber (Devon Toray Kevlar Kevlar 149 single yarn denier 1.42d.
e) Insulating coating 3 made of high-density polyethylene resin was performed while 8000 pieces were aligned to obtain heat-generating material 4 (FIG. 2) having 3 bundles of yarn strands, thickness 2.5 mm and width 8 mm.

[0023]

[Embodiment 3] One piece of nichrome wire (wire diameter 0.5 mm, cross-sectional area 0.196 mm ² ) is used as a heating resistor for all the yarn strands, and 2000 polyethylene terephthalate continuous filaments (6de manufactured by Teijin Ltd.) are used. Aligned fiber 2 was used. While bundling and aligning the heating resistor 1 and the array fiber 2, the insulation coating 3 made of high-density polyethylene resin is applied and the number of yarn strands is 21.
Heat generating material 4 (Fig. 1) with a bundle, thickness 2.5 mm and width 55 mm
I got

[0024]

[Embodiment 4] Three bundles of yarn strands are used as a heat-generating material by changing dies and nipples, and the center position of the yarn strand is a nichrome wire (strand diameter 0.5 mm, cross-sectional area 0.196 mm ² ).
Three were used as the heating resistor 1, and 2000 polyethylene terephthalate long fibers (6de manufactured by Teijin Ltd.) were used as the array fiber 2. A heating resistor 1 and array fibers 2 are provided in the central strand.
Bundled and aligned, and the remaining strand is polyethylene terephthalate continuous filament (6de manufactured by Teijin Ltd.) 2000
Insulating coating 3 with high-density polyethylene resin is performed while aligning the books, and the number of yarn strands is 3 and the thickness is 2.5 m.
A heat generating material 4 (FIG. 2) having a width of m and a width of 8 mm was obtained.

[0025]

Example 5 100 stainless steel fibers (single yarn denier 8.35 de) were used as the heating resistor 1 in all the yarn strands, and polyparaphenylene terephthalamide continuous long fibers (Kevlar 149 single yarn denier 1.42 de manufactured by DuPont Toray Kevlar KK) were used. ) 8000 fibers were used as array fiber 2.
While the heating resistor 1 and the array fiber 2 are bundled and aligned, a metal oxide powder having a far infrared ray effect is mixed into a high density polyethylene resin to perform a metal oxide powder mixed insulation coating 6 and the number of yarn strands is 21 bundles, thickness A heat generating material 4 having a width of 2.5 mm and a width of 55 mm was obtained. Furthermore, the heat generating material 4 (FIG. 3) was obtained by attaching the metal foil 5 to the bottom of the heat generating material.

[0026]

[Comparative Example 1] road heating for Nichrome wire withstand voltage type, wire diameter 0.5 mm, the number of the wires 7 present, the first layer of ethylene-propylene rubber nichrome wire heating element wire the total cross-sectional area 1.40 mm ^2, two Layer heat-resistant polyvinyl chloride resin coating,
Third layer heat resistant polyvinyl chloride resin coated outer diameter 8.7m
It is a heat generating material having a circular cross section of m.

[0027]

[Comparative Example 2] A carbon compound heating resistor for load heating has a polyethylene resin as a core material,
It is a heat generating material having a round cross section, the periphery of which is covered with a carbon compound heat generating resistor, and the periphery of which is coated with polyethylene resin.

[0028]

[Comparative Example 3] The heating element portion of the heat-generating material mixed with the stainless fiber for load heating and the aramid fiber is formed by twisting the discontinuous stainless fiber and the discontinuous aramid fiber. The heating resistor thread fineness is 60000 de and the heating resistor outer diameter is 2.6 mm. The heat-generating resistor is coated with two layers of heat-resistant vinyl chloride resin, and the third layer is coated with polyethylene terephthalate long fiber cords.
It is a 0 mm round section heat generating material.

[0029] Each heat generating material is 3 in the area off Harue-cho, Sakai-gun, Fukui prefecture
Maeda Kosen Co., Ltd. No. 8-3 was lined up and fixed on a steel frame grating for inner side road gutters. When a vehicle passed over it, compressive load, shear stress, and bending stress were applied to the heat-generating material, and the degree of damage over time was compared by measuring the resistance value. The heat generating material length was 12 m. The results are shown in Table 1.

Each exothermic material was embedded in mortar after being connected in series with a power supply of 20 W per m (FIG. 4). The mortar has a block shape with a thickness of 10 cm and a length and width of 50 cm. Next, this hat exothermic material embedded block is placed at -5 ° C.
In the low temperature constant temperature box, the temperature of the block was stabilized after 4 hours and the block surface temperature was measured at two locations and the internal temperature was measured at one location. Table 2 shows the results. The heating material embedding depth was set at a position of 50 mm from the surface of the block, measurement position 1 was a surface portion immediately above the heating material, measurement position 2 was a surface portion between the heating material and the heating material, and measurement position 3 was a portion 10 mm directly above the heating material.

[0031]

[Table 1]

[0032]

[Table 2]

When the heat-generating material of the present invention is used, the compressive load is absorbed by the array fibers having a small breaking elongation and a large breaking strength. For this reason, disconnection of the heating resistor and resistance value change hardly occur, and the durability is excellent.

When the heat-generating material of the present invention is used, the surface temperature of the mortar block can be increased as compared with the conventional heat-generating material, and snow melting is easy.

[Brief description of drawings]

FIG. 1 is a perspective view of exothermic materials of Examples 1 and 3. FIG.

FIG. 2 is a perspective view of heat-generating materials of Examples 2 and 4.

FIG. 3 is a perspective view of a heat generating material according to a fifth embodiment.

FIG. 4 is a perspective view of a mortar block for snow melting in which the heat generating material of the present invention is embedded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating resistor 2 Arrangement fiber 3 Insulation coating resin 4 Heating material 5 Metal foil 6 Metal oxide powder mixed insulation coating resin

Claims (7)

[Claims] 1. A fiber having a breaking elongation of 0.5% or more and 20% or less and a breaking strength of 6 g / de or more and 100 g / de or less, using stainless fiber, stainless wire, or nichrome wire as a heating resistor. A heat-generating material characterized by arranging the above and further forming an insulating coating resin layer on the periphery thereof. 2. The heat generating material according to claim 1, wherein the insulating resin coating shape is a flat plate-like rectangular cross section. 3. The fibers arranged around the heating resistor are aramid fibers, arylate fibers, high-strength polyethylene fibers,
The heat generating material according to claim 1 or 2, wherein polyester fiber, nylon fiber, glass fiber, or carbon fiber is used. 4. The flat plate-shaped rectangular cross-section heat-generating material has a thickness of 2.0 mm or more and 20 mm or less and a width of 2.0 mm or more and 200 mm or less while maintaining strength by fibers arranged around the heat-generating resistor. Item 1, 2 or 3 of the heat generating material. 5. The heat-generating material according to claim 1, 2, 3 or 4, wherein at least one bundle and not more than 100 bundles of yarn strands in which fibers are arranged around the heat-generating resistor are simultaneously insulation-coated. 6. The amount of heat generated in the upper part is improved by kneading a metal oxide powder having a far infrared effect into an insulating coating resin and adhering a metal foil or a metal vapor deposition film on one surface of the heat generating material. The heat generating material according to 2, 3, 4 or 5. 7. The metal oxide powder used is titanium oxide, silicon oxide, iron oxide, aluminum oxide, calcium oxide, potassium oxide or nickel oxide.
The heat generating material according to 2, 3, 4, 5 or 6.