JP3033468B2 - 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 be put to practical use as a temperature sensor because its temperature-sensitive characteristics vary greatly with 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. 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, there is provided a polyamide comprising at least one additive selected from the group consisting of an iodine or an iodine compound additive, zinc oxide and a hindered phenol or naphthylamine. The composition is used as a temperature sensitive 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 resistance stability of these temperature sensors and temperature-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 chain in 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, copper iodide is generated, and 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 an interlocking cycle in which the effect of improving the current-carrying stability works. Therefore, the thermal stability of the polymer thermosensitive body can be improved, and the heat resistance stability as a temperature sensor or a thermosensitive heater can be significantly increased.

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. Moreover, the antioxidant property of hindered phenol or naphthylamine makes the composition thermally stable.

In the present invention, the combination of zinc oxide and zinc oxide with a hindered phenol or naphthylamine is not excluded from each other even if the action is duplicated, but has a synergistic action when added. Therefore, it is considered that the thermal stability of the polymer thermosensitive body is improved, and the thermal stability as a temperature sensor or a thermosensitive heater is remarkably increased. Further, by blending an aldehyde polycondensate of a phenol compound, a strong moisture absorption preventing action can be imparted. 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.

[0011]

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. 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, a zinc oxide powder having a particle diameter of 0.1 to 0.5 μm was used. In order to enhance antioxidant properties and thermal stability, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate (molecular weight 586.8) and pentane are used as hindered phenols. Erythrityl-tetrakis [3- (3.5-di-t-
Butyl-4-hydroxyphenyl) propionate (1177.7 molecular weight), N, N'-hexamethylenebis (3.5-di-tert-butyl-4-hydroxy-hydroxynamamide) (637.0 molecular weight), 3.9-bis {2- [3- (3-t-butyl-4-hydroxy-5-
Methylphenyl) propionyloxy] -1,1-dimethylethyl {-2,4,8,10-tetraoxaspiro [5.5] undecane (molecular weight 741), and phenyl-α-naphthylamine (molecular weight 404) as naphthylamine. ). Further, in the example in which an aldehyde polycondensate of a phenol compound was added, an octyl oxybenzoate-formaldehyde polycondensate having good compatibility with polyamide was selected, and the amount was 15 parts by weight.

A sample is prepared by mixing these components, kneading them with an extruder, and then using a hot press to obtain a sample of about 70 × 70 mm and a thickness of 1
mm sheet, and copper electrodes were provided on both sides of the sheet. 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 was represented by a thermistor B constant at 40 to 80 ° C. The heat stability is 12
An air heating aging test at 0 ° C. was performed on a dumbbell specimen, and the evaluation was made based on the time at which the yield point strength was reduced by half. further,
Initial impedance at 100 ° C and 1 at 100 ° C
It was expressed as a temperature difference (ΔT ₂ ) from the impedance after the application of a half-wave current of 00 V for 1,000 hours. 40 to 8
The thermistor B constant at 0 ° C. is the impedance Z _{40 at} 40 ° C. and the impedance Z _{80 at} 80 ° C.
Was calculated based on the measurement results. Table 1 shows these results.
And Table 2.

[0013]

[Table 1]

[0014]

[Table 2]

The sensitizer of the present invention includes 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, and poly [(2-oxo-1-pyrrolidinyl) ethylene] iodide and hydrates thereof are used, and contribute to the improvement of the thermistor B constant.

Further, other than these, palladium iodide,
Any compound containing iodine, such as silver iodide or neodymium iodide, may be used. These are 0.01 to 3 with respect to polyamide.
0 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 when the iodine donor is an iodine organic compound, the combination with zinc iodide exhibits a sensitizing effect and a half-wave current stabilizing effect.

As an antioxidant, triethylene glycol-bis [3- (3-t) is used as a hindered phenol.
-Butyl-5-methyl-4-hydroxyphenyl) propionate] or pentaerythrityl-tetrakis [3- (3.5-di-t-butyl-4-hydroxyphenyl) propionate] or N, N'-hexamethylenebis (3.5-di-t-butyl-4-hydroxy-hydroxy namamide) or 3.9-bis {2- [3-
(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl
-2,4,8,10-Tetraoxaspiro [5.5] undecane and naphthylamine are used and contribute to improvement of heat resistance. These combinations exert a further synergistic effect. Further, in the example in which the phenolic compound is added, the aldehyde polycondensate of the phenolic compound having good compatibility with the polyamide includes octyl p-oxybenzoate-aldehyde polycondensate and isostearyl p-oxybenzoate. -Formaldehyde polycondensates are excellent in compatibility and moisture resistance, but in addition to p-oxybenzoic acid alkyl esters, aldehyde polycondensates such as p-dodecylphenol, p-chlorophenol, p-oxybenzoic acid nonyl esters, etc. It may be a condensate. 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 if it is more than 30 parts by weight, the properties of the composition are significantly impaired.

Nylon 12 (10
0 parts by weight), cobalt iodide (5.0 parts by weight), zinc oxide (5.0 parts by weight), pentaerythrityl-tetrakis [3- (3.5-di-t-butyl-4-hydroxyphenyl) A pellet of a nylon compound consisting of [propionate] (0.5 parts by weight) was prepared, and the pellet was used to prepare a temperature-sensitive element as shown in FIG. 1, that is, a temperature detection heater wire. Here, each component will be described.
1 is a polyester core yarn of 1,500 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 with respect to a trial product in which a thermosensitive layer was formed only with nylon 12.
It was doubled to 13,600 (K), and showed a durability of 3,000 hours or more against continuous 100 V half-wave energization at 100 ° C. performed as a heat resistance life test. Also, 0.5
In the case where an electrode wire in which approximately 30 μm of nickel plating was applied to a% silver-containing copper electrode wire, durability of 8,000 hours or more was exhibited.

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 heat insulation, and is provided with an electric carpet, an electric blanket, an electric cushion, a floor mat, an electric floor heating, Long life and high safety can be imparted to electric heating devices such as wall heaters, panel heaters, electric futons, electric foot warmers, and car seat heaters. Prototype area 180cm square, power consumption 61
The 0-watt electric carpet showed 10 times or more the durability at 100 ° C. as compared to the conventional heater wire with temperature detection.

[0021]

As described above, according to the present invention, the combined use of iodide and zinc oxide with hindered phenol or naphthylamine can improve the thermistor B constant and maintain mechanical properties for a long time even at high temperatures. Stability in strength and electrical properties can improve the reliability of many practical applications.

Further, the constitution according to the third and fourth aspects makes it possible to further increase the stability, and the use of the composition according to the fifth aspect improves the temperature resistance and further improves the performance stability. Can be improved.

Further, by adopting the structure of claim 8,
The change in the duty ratio with respect to the temperature change is small, so that the performance can be stabilized. In addition, by adopting the configuration of claim 9, the current supply stability and the cost reduction can be achieved at the same time, and it can be made more practical. .

[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 C08K 5/18 C08K 5/18 C08L 77/00 C08L 77/00 H01C 7/04 H01C 7/04 H05B 3/56 H05B 3/56 C (56) References JP-A-7-29705 (JP, A) JP-A-6-323925 (JP, A) JP-A-60-106104 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) G01K 7/16

Claims (11)

(57) [Claims] 1. A polymer thermosensitive material comprising a polyamide composition comprising polyamide and at least one additive selected from iodine or an iodine compound, zinc oxide, and at least one selected from hindered phenol and naphthylamine. body. 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 method of claim 1, wherein the hindered phenol is triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4).
-Hydroxyphenyl) propionate] or pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] or N, N'-hexamethylenebis (3,5-di-t -Butyl-4-hydroxy-hydroxynamamide) or 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy]-
The polymer thermosensor according to claim 1, which is at least one selected from 1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane. 4. The thermosensitive polymer according to claim 1, wherein the naphthylamine is at least one selected from phenyl-α-naphthylamine and N′N-di-β-naphthyl-p-phenylenediamine. 5. The polymer thermosensor according to claim 1, wherein the polyamide composition comprises a polycondensate of oxybenzoate and formaldehyde. 6. 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 7. A thermosensitive element comprising the polymer thermosensitive body according to claim 1 disposed between a pair of electrodes. 8. The electrode according to claim 7, 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. 9. The electrode according to claim 7, wherein the surface layer of any 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. 10. An electric heater using the temperature-sensitive element according to claim 7. 11. The electric warmer according to claim 10, 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.