JP3036403B2 - Polymer thermosensor, thermosensor using the same, and electric heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer thermosensor used for a flexible temperature sensor or a temperature-sensitive heater such as an electric heater, a thermosensitive element using the same, and an electric heater.

[0002]

2. Description of the Related Art Conventionally, a polymer thermosensor is generally disposed between a pair of winding electrodes and used as a flexible linear temperature sensor or a heat-sensitive heater. Examples of the polymer thermosensitive material include nylon 12 and modified nylon 11 (ATO-CHIMI) disclosed in JP-A-55-100693.
A polyamide composition such as "Rilsan N nylon" (trade name, manufactured by Company E) is used, and its temperature change such as capacitance, electric resistance, or impedance is used to perform the function of a temperature sensor. Furthermore, Japanese Patent Publication No. 60-48081
JP-A-64-30203 discloses an example of an ion conductive heat-sensitive composition containing a copper deactivator and a phenolic antioxidant. Is disclosed.

[0003]

Nylon 12 is excellent in that it has a low moisture absorption rate, but is difficult to use practically as a temperature sensor because the temperature-sensitive characteristics vary greatly with temperature. Further, in the modified polyamide disclosed in JP-A-55-100693, the temperature dependency of impedance is small, so that the temperature detection sensitivity is low and the heat resistance stability is poor. Therefore, in order to improve humidity resistance and temperature sensitivity, there has been proposed a composition containing an aldehyde polycondensate of a phenolic compound as disclosed in Japanese Patent Publication No. 3-50401. However, all of them have problems such as low temperature dependence of impedance and insufficient thermal stability over a long period of time.

[0004] It is an object of the present invention to provide a polymer thermosensor having a large impedance temperature dependence and excellent thermal stability.

[0005]

According to the present invention, a polyamide composition obtained by mixing at least an additive consisting of iodine or an iodine compound and zinc oxide with a polyamide is used as a thermosensitive body.

[0006]

Generally, a polymer thermosensor is disposed between a pair of copper or copper alloy winding electrodes, and is used as a flexible linear temperature sensor or a thermal heater. The heat stability of these temperature sensors and heat-sensitive heaters is determined by the stability of the polymer thermosensor itself and the surface condition of the winding electrode.

When the polyamide composition of the present invention is used,
The temperature dependence of impedance is remarkably enhanced by the ion carrier property of the iodine metal compound in the polymer thermosensor. In addition, iodine generated from an iodine organic compound reacts with zinc oxide to generate zinc iodide. The generated zinc iodide increases the temperature dependence of the impedance, forms a zinc complex with the amide group, increases the current-carrying stability, and becomes thermally stable. In addition, iodine generated from an iodine compound when used at a high temperature for a long period of time is localized around the amide group, while acting as an iodine ion on a metal electrode to generate a metal iodide that is an electrical insulator, Impairs the stability of the impedance between the electrodes. For example, when copper is used for the electrode,
Since copper iodide is generated, it is difficult to obtain the temporal stability of the impedance between the electrodes. Therefore, when zinc oxide is used in combination, the zinc oxide acts as an iodine ion acceptor and can prevent the generation of iodine metal on the surface of the metal electrode. further,
It is considered that the zinc oxide forms zinc iodide and acts to improve the current-carrying stability, thereby functioning the inter-ring cycle. Therefore, the thermal stability of the polymer thermosensor is improved,
The heat stability can be remarkably increased as a temperature sensor or a thermal heater.

Further, a strong moisture absorption preventing action can be imparted by blending an aldehyde polycondensate of a phenol compound. Phenolic compounds have good compatibility with polyamides, and coordinate with hydrogen bonding sites in polyamide instead of water molecules to reduce hygroscopicity and reduce fluctuations in temperature-sensitive characteristics due to humidity. There is also an effect of increasing the temperature sensitivity by acting on the amide group.

When the electrode material is a noble metal such as gold, platinum or palladium, or is plated, the generation of metal iodide is hardly observed, but silver, tin, solder, stainless steel, titanium, When using indium or the like, these metal iodides have relatively high conductivity,
The temporal stability of the impedance between the electrodes can be improved. Further, in the case where the compound is formed only on the surface layer as described above, the inner layer can be made of a low-priced and highly conductive material, so that the current-carrying stability and cost reduction can be realized.

[0010]

Embodiments of the present invention will be described below. In Examples of the present invention, as the polyamide, nylon 12, nylon 12-nylon 40 copolymer having low hygroscopicity,
N-alkyl-substituted polyamide 11, polyetheramide, and dimer acid-containing amide were selected. As a conductivity-imparting agent for increasing the temperature dependence of the impedance of these polymers, a metal iodide compound having high thermal stability was used. Also,
Poly [(2-oxo-1-pyrrolidinyl) ethylene] iodo was selected as the organic iodine compound as the iodine donor. Particle size 0.1-0.5 as iodine receptor
μm zinc oxide powder was used. Further, in the example in which an aldehyde polycondensate of a phenol compound was added, an octyl oxybenzoate-formaldehyde polycondensate having good compatibility with the polyamide was selected to be 15 parts by weight. The sample was prepared by mixing these components, kneading them with an extruder, forming them into a sheet having a size of about 70 × 70 mm and a thickness of 1 mm by a heat press, and providing copper electrode portions on both surfaces thereof. The electrode material dependence was determined by using a silver plate, a gold plate, and a copper plate which were subjected to silver plating, tin plating, and solder plating. The temperature dependence of the impedance is thermistor B at 40 to 80 ° C.
Expressed as a constant. In addition, the thermal stability is such that the initial impedance at 100 ° C. and the half-wave current of 100 V
Temperature difference (ΔT
_Z ). The impedance B constant at 40 to 80 ° C. is the impedance Z ₄₀ and 80 at 40 ° C.
The results of measuring the impedance Z ₈₀ at ℃ calculated based.

The results are shown in (Table 1) and Table 2.

[0012]

[Table 1]

[0013]

[Table 2]

The sensitizers of the present invention include tin iodide, antimony iodide, copper iodide, nickel iodide, manganese iodide, cobalt iodide, iron iodide, lead iodide, cadmium iodide and iodide. Iodine compounds such as titanium, sodium iodide, potassium iodide, poly [2-oxo-1-pyrrolidinyl) ethylene] iodide, and hydrates thereof are used, and contribute to the improvement of the thermistor B constant.

In addition, compounds containing iodine, such as palladium iodide, silver iodide, and neodymium iodide, may be used. These are 0.01 to
30 parts by weight are blended. If the amount is less than 0.01 part by weight, the sensitizing property and the half-wave current stabilizing effect are low, and if it is more than 30 parts by weight, the physical properties of the composition are significantly impaired. In addition, zinc oxide is used as a receptor for iodine ions generated from an iodine compound when used at a high temperature for a long period of time, which contributes to prevention of generation of iodine metal on the surface of a metal electrode. Furthermore, it is considered that zinc oxide functions as an inter-ring cycle in which zinc iodide generates zinc iodide and acts to improve current-carrying stability. Therefore, the thermal stability of the polymer thermosensitive body can be improved, and the thermal stability as a temperature sensor thermosensitive heater can be significantly increased. These are based on polyamide, 0.0
1 to 30 parts by weight is blended. If the amount is less than 0.1 part by weight, the effect is low, and if it is more than 30 parts by weight, the physical properties of the composition are significantly impaired. Needless to say, even if the iodine donor is an iodine organic compound, the combination with zinc iodide exerts sensitizing properties and half-wave current stabilizing effects.

In the case where an aldehyde polycondensate of a phenol compound is further added, the aldehyde polycondensate of a phenolic compound having good compatibility with polyamide includes octyl p-oxybenzoate-aldehyde polycondensate and p-oxy Benzoic acid isostearyl ester-formaldehyde polycondensate is excellent in compatibility and moisture resistance, but p-oxybenzoic acid alkyl ester other than p-oxybenzoic acid alkyl ester
Aldehyde polycondensates such as dodecylphenol, p-chlorophenol, and nonyl p-oxybenzoate may be used. These are blended in an amount of 5 to 30 parts by weight with respect to the polyamide. If the amount is less than 5 parts by weight, the effect is low and 3
If the amount is more than 0 parts by weight, the properties of the composition are significantly impaired.

For evaluation of the thermosensitive element, nylon 12 (10
0 parts by weight), pellets of a nylon compound comprising cobalt iodide (5.0 parts by weight) and zinc oxide (5.0 parts by weight), and using the pellets, a temperature-sensitive element as shown in FIG. That is, a temperature detection heater was prepared.

Here, each component will be described.
1 is a polyester core yarn of 1500 denier, 2 is 0.5
% Silver-containing copper electrode wire, 3 is a nylon thermosensitive layer, 4 is a heating / temperature detecting electrode wire, and 5 is a heat-resistant polyvinyl chloride jacket. For the purpose of comparison, the thermistor B constant was about 3.3 times that of the sample in which the thermosensitive layer was formed only with nylon 12 at 13600.
(K), which showed a durability of 3000 hours or more against continuous 100 V half-wave energization at 100 ° C. performed as a heat resistance life test. In addition, when an electrode wire in which a nickel plating of about 30 μm was applied to a 0.5% silver-containing copper electrode wire was used, the durability was 8000 hours or more.

Further, since the heat-generating integrated wire provided with the temperature detection is excellent in heat resistance, it exhibits stable performance with respect to heat insulation and insulation, and can be used for electric carpets, electric blankets, electric cushions, and the like.
Electric heaters such as floor mats, electric floor heaters, wall heaters, panel heaters, electric futons, electric foot heaters and car seat heaters can be provided with a long life and high safety. The prototype electric carpet having an area of 180 cm square and consuming 610 watts showed more than 10 times the conduction durability at 100 ° C. as compared with the conventional heater wire with temperature detection.

[0020]

As described above, according to the present invention, the combined use of an iodine compound and zinc oxide can improve the thermistor B constant and stabilize the mechanical strength and electrical characteristics over a long period of time even at high temperatures. As such, the reliability of many practical applications can be improved.

Further, by using a polyamide composition containing an oxybenzoate-formaldehyde polycondensate, the moisture resistance can be improved and the performance stability can be further improved.

Further, copper, aluminum,
In the case of using gold, platinum, palladium, silver, tin, solder nickel, stainless steel, titanium, and indium, there is little change in the electric conductivity with respect to temperature change, and the performance can be more stabilized.

Further, by forming an oxide different from the internal layer on the surface layer so as to form a compound formed by the above-mentioned metal, it is possible to simultaneously improve the current-carrying stability and reduce the cost, making the device more practical. be able to.

[Brief description of the drawings]

FIG. 1 is a partially broken side view of a temperature detecting heater wire using a temperature sensing element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyester core yarn 2 Electrode wire 3 Nylon thermosensitive layer 4 Heat generation / temperature detection electrode wire 5 Polyvinyl chloride jacket

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 77/00 C08L 77/00 H01C 7/04 H01C 7/04 H05B 3/56 H05B 3/56 C (56) References JP JP-A-6-151112 (JP, A) JP-A-6-323922 (JP, A) JP-A-6-323924 (JP, A) JP-A-6-323926 (JP, A) JP-A-7-29705 (JP) JP-A-6-323925 (JP, A) JP-A-60-106104 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01K 7/16

Claims (9)

(57) [Claims] 1. A polymer thermosensor comprising a polyamide composition comprising polyamide and at least an additive comprising iodine or an iodine compound and zinc oxide. 2. An iodine compound comprising at least tin iodide, antimony iodide, copper iodide, nickel iodide, manganese iodide, cobalt iodide, iron iodide, lead iodide, cadmium iodide, and titanium iodide. 2. The thermosensitive polymer according to claim 1, comprising sodium iodide, potassium iodide and hydrates thereof. 3. The polyamide composition according to claim 1, which comprises a polycondensate of oxybenzoate and formaldehyde.
The polymer thermosensitive body according to the above. 4. The polymer thermosensor according to claim 1, wherein the polyamide is at least one selected from the group consisting of the following (a) to (f). (A) Polyundecaneamide (b) Polydodecaneamide (c) Polyamide containing linear saturated hydrocarbon C ₁₀ or more and copolymer thereof (d) Polyundecaneamide or N-alkyl-substituted amide copolymer of polydodecaneamide (E) Polyundecaneamide or etheramide copolymer of polydodecaneamide (f) Dimer acid-containing polyamide 5. A temperature sensing element comprising the polymer temperature sensing element according to claim 1 disposed between a pair of electrodes. 6. An electrode according to claim 5, wherein one or both electrodes are made of copper, aluminum, gold, platinum, palladium, silver, tin, solder, nickel, stainless steel, titanium, or indium. A temperature-sensitive element. 7. The electrode according to claim 5, wherein the surface layer of one or both electrodes is made of gold, platinum, palladium,
A temperature-sensitive element provided by using an electrode made of another metal different from an internal layer containing silver, tin, solder, nickel, titanium, and indium. 8. An electric heater using the temperature-sensitive element according to claim 5. 9. The electric warmer according to claim 8, including an electric carpet, an electric blanket, an electric cushion, a floor mat, an electric floor heater, a wall heater, a panel heater, an electric futon, an electric foot heater, a car seat heater, and the like. Electric warmer.