JP2743833B2 - Polymer thermosensor and thermosensor using the same - 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 such as an electric heater or a thermosensor.

[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. In Japanese Patent Publication No. Sho 60-48081, a polyamide composition containing a phosphite as a thermal deterioration improving agent is disclosed. In Japanese Patent Application Laid-Open No. Sho 64-30203, a ionic conductive material containing a copper deactivator and a phenolic antioxidant is added. Examples of sensible thermosensitive compositions are disclosed.

[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. 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. Further, when used as a temperature sensor for an electric warming device or the like, the temperature sensitive body is exposed to high temperature (1
(00 to 120 ° C.) in some cases. When a half-wave electric field is applied to the above-mentioned thermosensitive body composition, since it is an ion-conductive substance, it causes severe polarization and a large temporal change in impedance, which has a problem in practical use.

[0004] The present invention relates to a polymer thermosensor having a large temperature dependence of impedance, excellent thermal stability, and a temperature sensing function that is stable even when conducting half-wave current for a long time. An object of the present invention is to provide a thermosensitive element using a warm body.

[0005]

According to the present invention, there is provided a thermosensitive element comprising a composition comprising polyamide and at least manganese iodide and at least one selected from hindered phenol and naphthylamine. Is a device in which a thermosensitive polymer is disposed between a pair of electrodes.

[0006]

Generally, a polymer thermosensitive element is disposed between a pair of copper or copper alloy winding electrodes and used as a flexible linear temperature sensor or 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 above-mentioned polyamide composition is used, the temperature dependence of impedance is remarkably increased due to the ion carrier property of manganese iodide in the polymer thermosensor, and a manganese complex is formed on the amide group to improve the current-carrying stability. Enhance. In addition, the antioxidant property of hindered phenol or naphthylamine makes it thermally stable. As in the present invention, the combination of manganese oxide and 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.

[0007]

Embodiments of the present invention will be described below. Departure
In the example of the light, the polyamide is less hygroscopic
Nylon 12, N-alkyl substituted polyamide 11, poly
Ether amides and dimer acid containing amides were selected. this
To increase the temperature dependence of the impedance of these polymers
Manganese iodide with high thermal stability
Was. Also hindered to increase antioxidant properties and thermal stability
As dophenol, triethylene glycol-bis
[3- (3-tert-butyl-5-methyl-4-hydroxy
Phenyl) propionate (molecular weight 586.8), pen
Taerythrityl-tetrakis [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate (min
1177.7), N, N'-hexamethylenebis
(3,5-di-tert-butyl-4-hydroxy-hydroxy)
Cinnamamide) (molecular weight 637.0), 3,9-bis
{2- [3- (3-t-butyl-4-hydroxy-5-
Methylphenyl) propionyloxy] -1,1-dim
Tyl ethyl｝ -2,4,8,10-tetraoxasubiro
[5,5] Undecane (molecular weight 741)
Phenyl-α-naphthylamine (min.
404). In addition, phenolic compounds
In the case of addition of aldehyde polycondensate, it is compatible with polyamide.
Octyl oxybenzoate-formaldehyde
A hydr polycondensate was selected and adjusted to 15 parts by weight. The sample
After compounding and kneading with an extruder, about
Formed into a 70 x 70 mm, 1 mm thick sheet, on both sides
It was prepared by providing a silver-coated surface electrode. Impedance temperature
The dependence is expressed as the thermistor B constant at 40 to 80 ° C.
did. In addition, the thermal stability is 100% with the initial impedance.
100V half-wave current at 1000C for 1000 hours
Temperature difference from impedance (ΔT _z). 40 ~
The thermistor B constant at 80 ° C is
Peedance Z₄₀And impedance Z at 80 ° C
₈₀Was calculated based on the measurement results.

The results are shown in (Table 1).

[0009]

[Table 1]

[0010] Manganese iodide is used as the sensitizer of the present invention, which contributes to the improvement of the thermistor B constant. It is considered that the combination of manganese iodide forms a manganese complex with an amide group in nylon, moderately suppresses the movement of manganese ions with respect to half-wave conduction, and prevents extreme polarization.

As an antioxidant, hindered phenol such as triethylene glycol-bis [3- (3-t
-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-tert-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-Tetraoxasbylo [5,5] undecane and naphthylamine are used and contribute to improvement of heat resistance. These combinations have even more synergistic effects.

The aldehyde polycondensates of phenolic compounds include octyl p-oxybenzoate-aldehyde polycondensate and isostearyl p-oxybenzoate-formaldehyde polycondensate in terms of compatibility and moisture resistance. Aldehyde polycondensates such as p-dodecylphenol, p-chlorophenol, and nonyl p-oxybenzoate other than the p-oxybenzoic acid alkyl ester. 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.

[0013] Nylon 12 (10
0 parts by weight), manganese iodide (1.0 parts by weight) N, N '
A pellet of a nylon compound comprising hexamethylene bis (3,5-t-butyl-4-hydroxy-hydroxynamamide) (0.5 part by weight) was prepared, and this pellet was used as shown in FIG. A thermosensitive element, that is, a temperature detection line was created. Here, each component will be described. 1 is a 1500 denier polyester core yarn, 2, 4
Is a 0.5% silver-containing copper electrode wire, 3 is a nylon thermosensitive layer, 5 is a polyester separation layer, and 6 is a heat-resistant vinyl chloride jacket. For comparison, the thermistor B constant was about 6 times as high as 90,000 for a sample in which a thermosensitive layer was formed only with nylon 12.
(K), which showed a durability of 2000 hours or more against continuous 100 V half-wave energization at 100 ° C. performed as a heat resistance life test.

[0014]

As described above, according to the present invention, the combined use of manganese iodide and hindered phenol or naphthylamine can improve the thermistor B constant and stabilize the mechanical strength and electrical properties over a long period of time even at high temperatures. As a matter of fact, the reliability of many practical applications can be improved.

[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 thread 2, 4 Electrode wire 3 Nylon thermosensitive layer 5 Polyester separation layer 6 Vinyl chloride jacket

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G01K 7/16 G01K 7/16 S // H05B 3/56 H05B 3/56 C

Claims (7)

(57) [Claims] 1. A thermosensitive polymer comprising a polyamide composition comprising a polyamide and at least manganese iodide and at least one selected from the group consisting of hindered phenol and naphthylamine. 2. The polymer thermosensitive body according to claim 1, wherein the manganese iodide is at least one selected from manganese iodide anhydrate and manganese iodide hydrate. 3. The hindered phenol is triethylene glycol bis [3- (3-tert-butyl-5-methyl-4).
-Hydroxyphenyl) propionate] or pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] or N, N'-hexamethylenebis (3,5-di -Tert-butyl-4-hydroxy-hydroxynamamide) or 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy]-
The polymer thermosensor according to claim 1, comprising at least one selected from 1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane. 4. The polymer thermosensor 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 polyamide composition according to claim 1, comprising an oxybenzoic acid ester and a formaldehyde polycondensate.
The polymer thermosensitive body according to the above. 6. 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) polyundecanamide (b) polydodecanamide (c) straight chain saturated hydrocarbon C ₁₂ polyamide containing more and copolymers thereof (d) polyundecanamide or N- substituted amide copolymer polydodecanamide (E) Polyundecaneamide or etheramide copolymer of polydodecaneamide (f) Dimer acid-containing polyamide 7. A thermosensitive element comprising the polymer thermosensitive element according to claim 1 disposed between a pair of electrodes.