JPH06323923A - Polymer temperature-sensor and thermosensitive element using it - Google Patents

Abstract

PURPOSE:To enhance the temperature dependency of an impedance and the thermal stability of the polymer temperature-sensor by a method wherein a composition in which iron iodide, a specific phosphorus ester-based compound and one or more kinds out of naphthyamine, phosphoric acid and a hindered phenol-based heatresistant stabilizer have been compounded with a polyamide is used as a temperature-sensor. CONSTITUTION:A temperature-sensor is formed of a polyamide composition is which iron iodide, a phosphorus ester-based compound at a phosphorus concentration of 3 to 20wt.% and at a molecular weight of 200 to 5000 and at least one kind out of naphtylamine, phosphoric acid and a hindered phenol-based heat-resistant stabilizer have been compounded with a polyamide. Then, the polymer temperature-sensor 3 is arranged and installed between one pair of electrode wires 2, 4, and a temperature change in its physical property is detected by both electrode wires 2, 4. Thereby, the contact of the polymer temperature-sensor with the winding electrodes is made good, and the heat- resistant stability of the temperaturesensing body as a temperature sensor can be enhanced.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a polymer temperature sensor is generally arranged between a pair of winding electrodes and used as a flexible linear temperature sensor or a heat sensitive heater. Examples of this polymer temperature sensitive material include nylon 12 and modified nylon 11 (ATO-CHIMI) disclosed in Japanese Patent Laid-Open No. 55-100693.
A polyamide composition such as "Rilsan N Nylon" manufactured by E Co., Ltd.) is used, and functions as a temperature sensor by detecting a temperature change such as capacitance, resistance value or impedance. Furthermore, Japanese Examined Japanese Patent Sho 60-48
No. 081 discloses a polyamide composition to which a phosphite ester is added as a heat deterioration improving agent, JP-A-64-30203.
Japanese Patent Laid-Open No. 2-16400 discloses an ion-conductive heat-sensitive composition containing a copper deactivator and a phenolic antioxidant.
Japanese Patent Publication No. 5 discloses an example of a polyvinyl chloride heat-sensitive composition containing a perchlorate and a triazole-based copper deactivator.

[0003]

However, in the conventional polymer temperature sensing element as described above, for example, nylon 12 is excellent in that it has a low hygroscopic rate, but as a temperature sensor, the variation of the temperature sensing characteristic due to humidity. Because it is large, it is difficult to put it to practical use. Further, in the modified polyamide disclosed in JP-A-55-100693, the temperature dependence 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, a composition containing an aldehyde polycondensate of a phenolic compound has been proposed as disclosed in Japanese Patent Publication No. 3-50401. However, all of these have low temperature dependence of impedance,
In addition, there are problems such as insufficient thermal stability for a long period of time.

An object of the present invention is to solve the above problems, and to provide a polymer temperature sensor having a large temperature dependency of impedance and excellent thermal stability, and a heat sensitive element using the same. It is a thing.

[0005]

In order to solve the above problems, the present invention provides a polyamide containing iron iodide and a phosphorus concentration of 3 to 3.
Use of a composition comprising a phosphite compound having a molecular weight of 200 to 5,000 at 20% by weight and at least one of naphthylamine, phosphoric acid or a hindered phenolic heat stabilizer as a temperature sensitive body It was done.

Further, the above-mentioned polymer temperature sensing element is arranged between a pair of electrodes, and the temperature change of the physical property of the polymer temperature sensing element is detected by both electrodes.

[0007]

In general, the polymer temperature sensor is disposed 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 heat resistance stability of these temperature sensors and heat sensitive heaters is determined by the stability of the polymer temperature sensor itself and the surface condition of the winding electrodes. When the polyamide composition of the present invention is used, high-temperature oxidation due to heating of the winding electrode is caused by at least one compound selected from naphthylamine, phosphoric acid or a hindered phenolic heat stabilizer in the polymer temperature sensor. Is significantly suppressed by its presence,
Moreover, the temperature dependence of the impedance is remarkably enhanced by the ion carrier property of the iodine metal compound to make it thermally stable. Moreover, such as tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite and hydrogenated phenol A / pentaerythritol phosphite polymer, diphosphite or tetraphosphite having a high molecular weight and a high phosphorus concentration. Alternatively, the thermal deterioration is remarkably suppressed by the synergistic effect of the antioxidant property and the reducing rust preventive effect of the phosphite-based polymer. This effect is low when the phosphorus concentration is low, and too high is not practical. A phosphorus concentration of 3 to 20% by weight is effective, but preferably 5 to 1
The best value is shown at 5% by weight. If the molecular weight is low, it tends to volatilize at high temperatures, resulting in poor sustainability of the effect. Also 5,00
If it exceeds, it becomes difficult to disperse.
3,500 is practical. By mixing naphthylamine, hindered phenol, and phosphoric acid in the presence of such an iodine metal compound and phosphite, rust prevention and oxidation can be synergistically achieved. This combination is not excluded from each other even if the actions overlap, but has a synergistic action by being added. Therefore, it is considered that the contact state between the polymer temperature sensor and the winding electrode is also improved, the thermal stability of the polymer temperature sensor is improved, and the heat resistance stability of the temperature sensor or the heat sensitive heater is significantly increased. Further, by blending an aldehyde polycondensate of a phenol compound, a strong moisture absorption preventing effect can be imparted. Phenolic compounds have good compatibility with polyamides and coordinate with hydrogen bonding sites in the polyamide instead of water molecules to reduce the hygroscopicity of the polyamide and reduce fluctuations in temperature-sensitive characteristics due to humidity. Further, the action on the amide group also has the effect of increasing the temperature sensitivity.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As the polyamide used in this example, nylon 12 having low hygroscopicity, modified polyamide 11, polyether amide, and polyamide containing dimer acid were selected.
An iodine compound such as iron iodide, which has high thermal stability, is suitable as a conductivity-imparting agent that increases the temperature dependence of the impedance of these polymers. Iron iodide anhydrous hydrate was selected as iron iodide. In addition, as a structure that acts synergistically with an iodine compound to enhance the antioxidant property and the reducing action, tetraphenyl dipropylene glycol diphosphite (molecular weight 566, phosphorus concentration 10.9% by weight), tetraphenyl tetra ( Tridecyl) pentaerythritol tetraphosphite (molecular weight 1,424, phosphorus concentration 8.7
%, Hydrogenated bisphenol A.pentaerythritol phosphite (molecular weight: 2,500 to 3,100, phosphorus concentration: 13.8% by weight). Further, phenyl-α-naphthylamine was added as a naphthylamine to enhance the heat resistance of the nylon temperature-sensitive composition.

Phosphoric acid is added to improve rust resistance and heat resistance.
To further improve the antioxidant property, pentaerythrityl-tetrakis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by CHIBA GEIGY, trade name "Irganox 1010") was selected. The composition ratio of all the additives was 0.5 to 1 part by weight with respect to 100 parts by weight of nylon. In the examples in which an aldehyde polycondensate of a phenol compound was added, an oxybenzoic acid octyl ester-formaldehyde polycondensate having good compatibility with polyamide was selected, and the amount was 15 parts by weight. As a specific example, the samples were blended with each other, kneaded by an extruder, and then formed into a sheet of about 70 × 70 mm and a thickness of 1 mm by a hot press, and a silver paint was applied to both surfaces of the sheet and dried to be used for measurement. A silver electrode was created. The temperature dependence of impedance is represented by the thermistor B constant at 40 to 80 ° C. Heat resistance stability is 80
Initial impedance at ℃ and 1000 at 150 ℃
The temperature showing the initial impedance of the sample after aging with heating air for time was determined and expressed as the temperature difference ΔT _Z between that temperature and 100 ° C.

The thermistor B constant at _{40 to} 80 ° C. is impedance Z _{40 at} 40 ° C. and 80 ° C.
It was calculated based on the result of measurement of the impedance Z ₈₀ at.

The results are shown in (Table 1).

[0012]

[Table 1]

In Table 1, the temperature sensitive characteristics of the polymer temperature sensitive bodies of Examples 1 to 7 and the polymer temperature sensitive bodies of Comparative Examples 1 to 4 were compared. As can be seen from the table, each of the polymer temperature sensitive bodies of Examples 1 to 7 has a B constant of 12000 ° K or higher,
It can be seen that it has a higher temperature detection ability than the conventional temperature sensitive bodies of Comparative Examples 1 to 4.

In this embodiment, iron iodide was used as a sensitizer, but this iron iodide contributes to heat sensitivity and heat resistance. Further, as the phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite, hydrogenated bisphenol A / pentaerythritol phosphite polymer is used, which has heat resistance and rust preventive action. Contribute to.

As naphthylamine, phenyl-α-
Naphthylamine is used and contributes to the improvement of heat resistance. Furthermore, phosphoric acid contributes to the improvement of rust prevention and heat resistance, and pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is used as a hindered phenol. By adding it, the thermal oxidation resistance performance is synergistically improved. As the hindered phenol, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-
Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester are desirable and the above combination is synergistic. Is effective in. Further, as the aldehyde polycondensate of the phenolic compound, p-oxybenzoic acid octyl ester-aldehyde polycondensate and p-oxybenzoic acid isostearyl ester-formaldehyde polycondensate are excellent in compatibility and moisture resistance. However, aldehyde polycondensates such as p-dodecylphenol, p-chlorophenol, and p-oxybenzoic acid nonyl ester may be used in addition to the p-oxybenzoic acid alkyl ester. These are mixed in 5 to 30 parts by weight with respect to the polyamide. If it is less than 5 parts by weight, the effect is low, and if it is more than 30 parts by weight, the physical properties of the matrix are significantly impaired.

Further, for evaluation as a heat sensitive element, nylon 12 (100 parts by weight), iron iodide (1 part by weight),
From hydrogenated bisphenol A pentaerythritol phosphite polymer (1 part by weight), pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (0.5 part by weight) Pellets of the following nylon compound were prepared, and the pellets were extruded to prepare a thermosensitive element having the structure shown in FIG. 1, that is, a temperature detection wire.

Each component of FIG. 1 will be described.
Is 1,500 denier polyester core yarn, 2,4 is 0.5
% Silver-filled copper electrode wire, 3 a nylon temperature-sensitive layer, 5 a polyester separation layer, and 6 a heat-resistant vinyl chloride jacket. The B constant of the thermistor of this embodiment is about four times the B constant of the thermosensitive element in which the temperature sensitive layer is formed only of nylon 12 of the comparative example, 13,0.
00 (K), the heat-sensitive element of this example showed durability about 2,000 hours or more, which is about seven times as much as that for continuous 100 V energization at 130 ° C.

[0018]

As is apparent from the above description, according to the present invention, a thermistor for a polymer thermosensitive material can be obtained by using iron iodide in combination with a phosphite ester having an appropriate molecular weight and phosphorus concentration. Increases the B constant and synergistically stabilizes mechanical strength and electrical properties at high temperatures over a long period of time. Also,
The combined use of naphthylamine, phosphoric acid and hindered phenol can improve rust prevention and heat resistance due to a synergistic effect. Furthermore, a highly reliable and highly sensitive heat sensitive element can be provided by using the polymer temperature sensitive body of the present invention.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing the structure of a temperature detection heater wire using a polymer temperature sensor according to an embodiment of the present invention.

[Explanation of symbols]

 1 Polyester core yarn 2,4 Electrode wire 3 Nylon temperature sensitive layer 5 Polyester separation layer 6 Heat resistant vinyl chloride jacket

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location C08K 5/524 KLB C08L 61/18 LNU 77/00 LQT H01C 7/00 X H05B 3/20 // H05B 3/56 B 7913-3K

Claims (7)

[Claims] 1. A polyamide containing iron iodide and a phosphorus concentration of 3
To 20% by weight and a molecular weight of 200 to 5,000 and a phosphite compound, and at least one of naphthylamine, phosphoric acid, or a hindered phenolic heat-resistant stabilizer are blended to form a polymer composition. Warm body. 2. The hindered phenol is triethylene glycol- [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-t-butyl-4-hydroxy-hydroxynamamide) or 3,9-bis {2- [ 3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy]-
The polymeric thermosensitizer according to claim 1, which is at least one selected from 1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane. 3. The polymer thermosensitizer according to claim 1, wherein the naphthylamine is at least one selected from phenyl-α-naphthylamine and N′N-di-β-naphthyl-p-phenylenediamine. 4. A phosphite compound is at least selected from tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite or hydrogenated phenol A / pentaerythritol phosphite polymer. The polymer thermosensitive material according to claim 1, which is one kind. 5. The polymer temperature sensitive body according to claim 1, wherein the polyamide composition comprises an oxybenzoic acid ester / formaldehyde polycondensate. 6. The polymer thermosensitive material according to claim 1, wherein the polyamide is at least one selected from the group consisting of the following (a) to (e). (A) Polyundecane amide (b) Polydodecanamide (c) N-alkyl-substituted amide copolymer of polyundecane amide or polydodecanamide (d) Ether amide copolymer of polyundecane amide or polydodecanamide (e) Polyamide containing dimer acid 7. A polymer temperature sensor according to any one of claims 1 to 7 is disposed between a pair of electrodes, and the temperature of the physical property of the polymer temperature sensor between the two electrodes. A heat-sensitive element that detects changes caused by the above-mentioned two electrodes.