JPH09159544A - Polymer temperature sensing element and temperature element using the material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensing element having high temperature resistance, the high temperature dependency of impedance, and high power supply stability by using a polymer temperature sensing material mainly composed of a polyamide composition containing zinc iodide, zinc hydroxide and a metal inert material blended with polyamide. SOLUTION: A polymer temperature sensing material to be used is mainly composed of a polyamide composition having zinc iodide, zinc hydroxide and a metal inert material blended with polyamide. Also, the polymer temperature sensing material is laid between electrodes as a pair. In this case, an electrode made of gold, platinum, palladium, copper, silver or the like, or another type of metal different from an inner layer containing such a material is used as one or both of the electrodes forming a pair, thereby forming a temperature sensing element. For example, a nylon blend material made of nylon 12, zinc iodide and zinc hydroxide is extruded to prepare a nylon temperature sensitive layer 3. Then, a temperature sensing element is formed out of an electrode wire 2 of silver-mixed copper wire, a heating wire 4 and a heat resistant polyvinyl chloride sheath 5 respectively wound around a polyester core thread 1.

Description

Detailed Description of the Invention

[0001]

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

[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, resistance value, or impedance is used to perform the function of a temperature sensor. Further, JP-A-58-215449 discloses a polyamide composition in which only iodine iodide, zinc iodide, is added to a polyamide to impart conductivity, thereby increasing the temperature dependence of impedance. .

[0003]

Nylon 12 is excellent in that it has a low moisture absorption rate, but is difficult to use as a temperature sensor because of its large fluctuation in temperature sensitivity due to humidity. 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. In order to improve the temperature dependence of impedance, Japanese Patent Application Laid-Open No. 58-2154.
Japanese Patent Publication No. 49 discloses a polyamide composition in which zinc iodide is mixed with polyamide as a conductivity-imparting agent.
When the temperature sensitive element having a configuration in which a metal electrode sandwiching a polymer temperature sensitive material using this polyamide composition is provided under an energized environment for a long period of time, polarization occurs in the polymer temperature sensitive element from aging, The change in impedance with respect to temperature does not follow up, and finally the phenomenon in which the temperature dependence of impedance becomes small occurs and correct temperature detection becomes impossible.

Further, when the thermosensitive element structure described above is used for a long period of time, the iodine component generated by the decomposition of the iodine compound in the polyamide composition is a metal which is in contact with the polymer thermosensitive material. Since the electrode surface is corroded, the resistance between the polymer temperature sensor and the electrode interface becomes high, and the impedance-temperature characteristic cannot be correctly detected as the temperature sensor.

The present invention solves the conventional problems as described above, and has a high heat resistance, a large temperature dependence of impedance, and an impedance-temperature characteristic that does not change even after a half-wave current is applied. It is an object of the present invention to provide a polyamide composition as a polymer temperature sensor having excellent stability, and a temperature sensor using the polymer temperature sensor.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a polymer composition mainly composed of a polyamide composition obtained by blending polyamide as a polymer thermosensitizer with zinc iodide, zinc hydroxide and a metal deactivator. Use a warm body. In addition, the above-mentioned polymer temperature sensing element is arranged between a pair of electrodes, and the temperature change of the physical properties of the polymer temperature sensing element is detected by both electrodes. One material is gold, platinum, palladium, copper, silver, tin, solder, titanium, nickel, indium, or gold, platinum, palladium copper, silver,
A temperature sensitive element using an electrode made of another metal different from the internal layer containing tin, solder, titanium, nickel, and indium is used.

Generally, a polymer temperature sensor is arranged between a pair of copper or copper alloy winding electrodes and is used as a flexible linear temperature sensor or a heat sensitive heater. The impedance-temperature dependence of these temperature sensors and heat sensitive heaters is
It is determined by the stability of the polymer temperature sensor itself and the surface condition of the winding electrode. When the above polyamide composition is used, the temperature dependence of the impedance is remarkably increased by the ion carrier property of zinc iodide in the polymer thermosensitizer, and a zinc complex is formed in the amide group to improve the current-carrying stability. , Is also thermally stable. However, while iodine generated from zinc iodide when used for a long time at high temperature is localized around the amide group, it acts on the metal electrode as iodine ion to generate metal iodide which is an electrical insulator, Impairs the stability of the impedance between the electrodes. For example, when copper is used for the electrode, copper iodide is generated, and it is difficult to obtain the temporal stability of the impedance between the electrodes. Therefore, when zinc hydroxide is used in combination, zinc hydroxide acts as a receptor for iodine ions and can prevent the formation of iodine metal on the surface of the metal electrode. Furthermore, it is considered that zinc hydroxide produces zinc iodide, which functions as a ring-linking cycle that acts to improve the stability of electrical conduction. Therefore, the impedance-temperature characteristic of the polymer temperature sensing element is improved, and the stability of the impedance temperature characteristic as a temperature sensor or a heat sensitive heater is maintained without impairing the temperature sensitivity in the polymer temperature sensing element even in a half-wave energized state. Can be significantly increased.

And as a metal deactivator, decamethylenedicarboxylic acid disalicyloyl hydrazide, N, N'-
Bis [3- (3,5-di-t-butyl-4-hinderedhydroxyphenyl) propionyl] hydrazine, benzotriazole and its derivatives, 1-hydroxymethylbenzotriazole, and 1,2-dicarboxyethylbenzotriazole. , Etc. can be added to stabilize the interfacial electric resistance between the copper electrode and the polyamide composition, and further, the heat resistance deterioration of the polyamide composition due to copper damage can be prevented.

The combination of zinc iodide, zinc hydroxide and the metal deactivator described above does not interfere with each other even if their actions overlap, but they have a synergistic effect by being added.

When the electrode material is a noble metal such as gold, platinum or palladium, or is plated,
The formation of metal iodide is difficult to see, but when silver, tin, solder, stainless steel, titanium, indium, etc. are used, the iodide of these metals has a relatively high conductivity, so the stability of the inter-electrode impedance over time is improved. Can be increased.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 of the present invention will be described below. In the present embodiment, as the polyamide,
Nylon 12, nylon 12-nylon 40 copolymer, N-alkyl-substituted polyamide 11, polyether amide, and dimer acid-containing amide having low hygroscopicity were selected. Zinc iodide having high thermal stability was used as a conductivity-imparting agent for increasing the temperature dependence of the impedance of these polymers.
As the iodine acceptor, zinc hydroxide powder of 0.1 μm to 0.5 μm was used.

Samples for measurement were prepared by blending these with various polyamides, kneading them with an extruder, and then molding them into a sheet of about 70 × 70 mm and a thickness of 1 mm by a heating press, and providing copper plate electrodes on both sides thereof. A measurement electrode was created. Also,
Dependence on electrode material is silver plate, gold plate, and copper plate with silver plating,
A tin-plated or solder-plated product was used. The temperature dependence of the impedance was represented by a thermistor B constant at 40 to 80 ° C.

As for the evaluation of the energization stability, FIG.
This will be described with reference to FIG. As shown in FIG.
Measure the volume specific impedance when changing to. Initial volume specific impedance characteristics (initial in Figure 2)
The volume specific impedance at 100 ° C is calculated from 10
After conducting 100 V half-wave rectification at 0 ° C. for 1000 hours (characteristics A and B in FIG. 2), the temperature showing the same volume specific impedance as in the initial stage is obtained, and the temperature difference at 100 ° C. is compared. In FIG. 2, since the temperature difference ΔTB> ΔTA, the characteristic A
It is judged that the current carrying stability is higher. Here, the temperature difference is represented by ΔTz. The thermistor B constant at 40 to 80 ° C. was calculated based on the results obtained by measuring the impedance Z40 at 40 ° C. and the impedance Z80 at 80 ° C.

The measurement results obtained by using a copper plate as an electrode material in a polymer temperature sensor using iodine and zinc hydroxide (Table 1)
In addition, Table 2 shows the measurement results of the polymer thermosensor using various types of electrodes for representative formulations from Table 1.

[0015]

[Table 1]

[0016]

[Table 2]

According to the first embodiment of the present invention, the thermistor B constant is about 10000 (K), which is almost three times higher than that of nylon alone, and the current-carrying stability is higher than that of iodine alone. The temperature shift is small, and the characteristic stability is improved.

Zinc iodide and zinc hydroxide are used in combination as a conductivity-imparting agent and a current-carrying stabilizer, which contributes to the improvement of the thermistor B constant and high-temperature current-carrying stability. These materials are
0.01 to 30 parts by weight are blended. If the amount is less than 0.01 part by weight, the sensitizing effect and the current stabilizing effect are low, and if the amount is more than 30 parts by weight, the physical properties of the polyamide composition are significantly impaired. In addition, when used at a high temperature for a long period of time, excess zinc hydroxide functions as an iodide ion acceptor, contributing to the prevention of the formation of metal iodide on the surface of the metal electrode. Furthermore, zinc hydroxide reacts with iodine in the hot melt kneading process,
It is considered that the ring-linking cycle that functions to produce zinc iodide and improve the stability of current flow works. Therefore,
It is possible to improve the thermal stability of the polymer temperature sensor and remarkably increase the thermal stability as a thermal heater with a temperature sensor.

Dependence of the electrode material on silver plate, gold plate, and copper plate used for silver plating, tin plating, and solder plating, and the same test results showed that in all cases, the same or more electric conduction stability than the copper plate was shown. I confirmed that. This is because the surface condition of the electrode is more stable than that of a copper plate, and greatly contributes to the current-carrying stability of the polymer thermosensor. In addition, if the electrode material is not easily oxidized other than the electrode materials listed here, the current-carrying stability is improved.

To evaluate the temperature sensitive element, nylon 12 (10
0 parts by weight), zinc iodide (7 parts by weight), zinc hydroxide (5 parts by weight)
(Parts by weight) to make a nylon compound pellets,
The pellets were extruded to form a temperature sensitive element having the structure shown in FIG. 1, that is, a temperature detection line. Referring to FIG. 1, 1 is a 1500 denier polyester core yarn, 2 is a 0.5% silver-containing copper wire electrode wire, 3 is a nylon thermosensitive layer of Example 1 of the present invention, and 4 is heat generation. Wire 5 is a heat resistant vinyl chloride jacket. The thermistor B constant of this temperature detection line was 10500 (K). Further, a heat resistance life test was performed. It showed durability for 3000 hours even with continuous 100 V energization at 120 ° C., and it was found that there was practically no problem.

According to the first embodiment of the present invention, the combined use of zinc iodide and zinc hydroxide can improve the thermistor B constant as a polymer temperature sensitive body and have stable current conduction characteristics.

Next, a second embodiment of the present invention will be described.
In the present embodiment, in addition to the polyamide, conductivity imparting agent and current stabilizer, zinc iodide acceptor and aldehyde deuterium compound of a phenolic compound shown in the embodiment, a copper electrode which acts synergistically with the above zinc hydroxide is provided. Metal deactivator decamethylenedicarboxylic acid disalicyloyl hydrazide, N, N'-bis [3-
(3,5-di-t-butylhydroxyphenyl) propionyl] hydrazine, 1-hydroxymethylbenzotriazole and 1,2-dicarboxyethylbenzotriazole as 1,2,3 benzotriazole and derivatives thereof were used.

As in the case of the first embodiment of the present invention, a sample for measurement is prepared by blending the above materials with various polyamides, kneading them with an extruder, and then heating them to about 70 × 70.
A sheet having a thickness of 1 mm and a thickness of 1 mm was formed, and electrodes of copper plates were provided on both surfaces of the sheet to prepare a measurement electrode. The electrode material dependence was a silver plate, a gold plate, or a copper plate plated with silver, tin, or solder. The temperature dependence of the impedance was represented by a thermistor B constant at 40 to 80 ° C. The heat stability was evaluated by performing an air heating aging test at 120 ° C. on a dumbbell test piece and evaluating the time at which the yield point strength was reduced by half. Furthermore, the evaluation of the energization stability is 1
Initial impedance at 00 ° C and 1 at 100 ° C
The temperature showing the initial impedance of the sample after conducting the half-wave energization of 00 V for 1000 hours was calculated and represented by the temperature difference ΔTZ from 100 ° C. The thermistor B constant at 40 to 80 ° C is impedance Z40 at 40 ° C.
And the impedance Z80 at 80 ° C. is measured,
It was calculated based on the results.

The measurement results obtained by using a copper plate as an electrode material in a polymer thermosensitizer prepared by combining zinc iodide and zinc hydroxide, an aldehyde polycondensate of a phenol compound, and a metal deactivator are shown in (Table 3). Further, (Table 4) shows the measurement results of the polymer temperature sensitive bodies using various electrode materials for typical formulations from (Table 3).

[0025]

[Table 3]

[0026]

[Table 4]

According to the second embodiment of the present invention, when a metal deactivator is blended, the heat resistance stability is shown by the results of the air heating aging test by the dumbbell test piece, and the polymer temperature-sensitive material according to the second embodiment of the present invention. It can be seen that the body also has a higher yield strength performance than the conventional case in which the above materials are not blended, and is excellent in heat stability. Moreover, the thermistor B constant and the energization stability are not impaired even if the materials of Embodiment 1 of the present invention are combined and blended. If a material that does not easily oxidize the electrode material is selected, the current-carrying stability is also improved. In addition, if the electrode material other than the electrode materials listed here is hardly oxidized, the current-carrying stability is improved.

In the present embodiment, zinc iodide and zinc hydroxide are used together as the conductivity-imparting agent and the current-carrying stabilizer, which contributes to the improvement of the thermistor B constant and high-temperature current-carrying stability. Since the metal deactivator stabilizes the interface between the copper electrode and the polyamide composition, it is possible to prevent heat deterioration of the polyamide composition due to copper damage.

Further, for evaluation as a temperature-sensitive element, nylon 12 (100 parts by weight), zinc iodide (7 parts by weight), zinc hydroxide (5 parts by weight) and decamethylenedicarboxylic acid disalicyloyl hydrazide. (0.5 parts by weight)
Pellets of the nylon blended with were prepared, and the pellets were extruded to prepare a temperature sensitive element having the configuration shown in FIG. 1, that is, a temperature detection wire. Explaining each component of FIG. 1, 1 is a polyester core yarn of 1,500 denier, 2 is an electrode wire of a copper wire containing 0.5% silver, and 3 is a nylon temperature-sensitive layer according to a second embodiment of the present invention. Reference numeral 4 is a heating wire, and 5 is a heat-resistant vinyl chloride jacket. The thermistor B constant of this temperature detection line was 11000 (K). In addition, it showed a durability of 5000 hours or more even when a continuous 100 V current was applied at 120 ° C., which was performed as a heat resistance life test, and it was found that there was no practical problem.

[0030]

As described above, according to the present invention, the following effects can be obtained.

(1) A polymer temperature sensitive material obtained by mixing polyamide iodide with zinc iodide and zinc hydroxide improves the thermistor B constant as compared with a nylon resin alone, and contributes to stable characteristics even after energization. To do.

(2) Further, by adding a metal deactivator to the above composition, mechanical strength and electrical properties are synergistically stabilized over a long period of time even in a high temperature storage test, and reliability in many practical applications is obtained. It is possible to provide a polymeric thermosensitive material having a high property. Further, by using the above-described polymer temperature sensitive body, a temperature sensitive heater wire having a high temperature detection sensitivity and a highly heat resistant temperature sensitive element can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a configuration of a temperature detecting heater wire using a polymer thermosensor of the present invention.

FIG. 2 is a diagram showing current-carrying stability evaluation from temperature dependence of volume specific impedance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyester core yarn 2 Electrode wire 3 Polymer temperature sensor of the present invention 4 Heating wire 5 Heat-resistant vinyl chloride jacket

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // (C08L 77/00 61:08)

Claims (8)

[Claims] 1. A polymer thermosensitizer mainly comprising a polyamide composition obtained by mixing a polyamide with zinc iodide, zinc hydroxide and a metal deactivator. 2. The polymer thermosensor according to claim 1, wherein the zinc iodide comprises at least one selected from zinc iodide anhydrate and zinc iodide hydrate. 3. A polyamide composition comprising an oxybenzoic acid ester and a formaldehyde polycondensate.
The polymer thermosensitive body according to the above. 4. The polymer thermosensitive body according to claim 1, wherein the polyamide is at least one selected from the group consisting of the following (a) to (f). (A) Polyundecane amide (b) Polydodecanamide (c) Polyamide containing linear saturated hydrocarbon C ₁₃ or more and its copolymer (d) Polyundecane amide or N-alkyl-substituted amide copolymer of polydodecane amide (E) Polyundecane amide or polydodecane amide ether amide copolymer (f) Dimer acid-containing polyamide 5. The polymeric thermosensitizer according to claim 1, wherein the metal deactivator contains at least one selected from the group consisting of the following (1) and (2). (1) Hydrazines: decamethylenedicarboxylic acid disalicyloyl hydrazide N, N'-bis [3- (3,5-di-t-butyl-4-
(Hydroxyphenyl) propionyl] hydrazine (2) Triazoles: Penzotriazole and its derivatives 6. A temperature-sensing device comprising the polymer temperature sensor according to any one of claims 1, 2, 3, 4, and 5, which is disposed between a pair of electrodes. element. 7. The temperature sensitive device according to claim 6, wherein one of the electrodes and the material of both electrodes are gold, platinum, palladium, silver, tin, solder, stainless steel, titanium, or indium. . 8. One of the electrodes and a material for both electrodes are gold, platinum, palladium, silver, tin, solder, titanium,
The temperature sensitive device according to claim 6, wherein the temperature sensitive device is provided by using an indium plating or a clad electrode.