JP3012959B2 - Polymer thermosensor and thermosensitive element 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 thermosensitive element used for a flexible temperature sensor or a temperature sensitive heater such as an electric heater, and a thermosensitive element using the same.

[0002]

2. Description of the Related Art Conventionally, this kind of polymer thermosensitive element is generally disposed between a pair of winding electrodes, and is used as a flexible linear temperature sensor or thermal sensor. Examples of the polymer thermosensitive material include nylon 12 and JP-A-55-100693.
Nylon 11 (ATO-C) disclosed in
A polyamide composition such as "Rilsan N nylon" (trade name, manufactured by HIMIE) is used, and functions as a temperature sensor by detecting a temperature change such as capacitance, resistance, or impedance. Japanese Patent Publication No. Sho 60-48081 discloses a polyamide composition containing a phosphite as a thermal deterioration improving agent. Japanese Patent Application Laid-Open No. Sho 64-30203 discloses a polyamide composition containing a copper deactivator and a phenolic antioxidant. A conductive thermosensitive composition is disclosed.

[0003]

However, in the above-mentioned conventional polymer thermosensitive material, for example, nylon 12 is excellent in that it has a low moisture absorption rate, but as a temperature sensor, fluctuation of temperature-sensitive characteristics due to humidity is required. Is difficult to use for practical use. 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 in which an aldehyde polycondensate of a phenolic compound is blended as disclosed in Japanese Patent Publication No. 3-50401. However, all of these have low temperature dependence of impedance,
There are also problems such as insufficient thermal stability over a long period of time.

An object of the present invention is to solve the above-mentioned problems, and to provide a polymer thermosensor having a large impedance temperature dependency and excellent thermal stability, and a thermosensor using the same. It is.

[0005]

According to the present invention, there is provided a polyamide comprising at least one selected from iron iodide and hindered phenol or naphthylamine.
A composition in which a seed is blended is used as a thermosensitive body.

Further, the above-mentioned polymer thermosensor is disposed between a pair of electrodes, and a temperature change in physical properties of the polymer thermosensor is detected by both electrodes.

[0007]

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 significantly increased due to the ion carrier properties of iron iodide in the polymer thermosensor. Furthermore, it forms an iron complex with an amide group to enhance the current-carrying stability. Moreover, due to the antioxidant properties of hindered phenol or naphthylamine,
It becomes thermally stable. The combination of iron iodide and hindered phenol or naphthylamine in the present invention is not excluded from each other even if the action is duplicated, but shows 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. It also has the effect of increasing the temperature sensitivity by acting on the amide group.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. In this example, nylon 12 having low hygroscopicity, N-alkyl-substituted polyamide 11, polyetheramide, and amide containing dimer acid were selected as polyamide. Iron iodide having high thermal stability was used as a conductivity-imparting agent for increasing the temperature dependence of the impedance of these polymers. 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 (molecular weight 1177.7), N, N'-hexamethylenebis (3
5-di-t-butyl-4-hydroxy-hydroxy namamide) (molecular weight 637.0), 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) was selected, and phenyl-α-naphthylamine (molecular weight 4
04) was selected. 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. After mixing these samples and kneading them with an extruder, about 70
It was formed into a sheet having a size of × 70 mm and a thickness of 1 mm, and silver-coated electrodes were provided on both sides thereof. The temperature dependence of the impedance was represented by a thermistor B constant at 40 to 80 ° C. The Samples of after 1,000 hours half-wave energization 100V in heat stability initial impedance and 80 ° C. at 100 ° C., obtains a temperature that indicates the initial impedance, temperature difference [Delta] T _Z between 100 ° C. expressed. 4
The thermistor B constant at 0 to 80 ° C. was calculated based on the results of measurement of the impedance Z ₈₀ of the impedance Z ₄₀ and 80 ° C. at 40 ° C..

The above polymer thermosensors were used as Examples 1 to 8 and compared with Comparative Examples 1 and 2, which are conventional polymer thermosensors. The results are shown in (Table 1).

[0010]

[Table 1]

In this embodiment, as a sensitizer, anhydrous iron iodide, iron iodide dihydrate, and iron iodide hexahydrate are used, which contributes to improvement of the thermistor B constant. As an antioxidant, a 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-t
-Butyl-4-hydroxy-hydroxynamamide) or 3,9-bis {2- [3- (3-tert-butyl-4-
[Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-
Tetraoxaspiro [5,5] undecane or naphthylamine is used, and contributes to improvement in heat resistance.
These combinations are even more synergistic than single effects. As the aldehyde polycondensate of a phenolic compound, p-oxybenzoic acid octyl ester-aldehyde polycondensate or p-oxybenzoic acid isostearyl ester-formaldehyde polycondensate is compatible with polyamide and has high moisture resistance. Although it is excellent in point, an aldehyde polycondensate such as p-dodecylphenol, p-chlorophenol or nonyl p-oxybenzoate may be used in addition to the alkyl ester of p-oxybenzoic acid. These are 5 to 3 with respect to polyamide.
0 parts by weight are blended. 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 for evaluation as a heat-sensitive element
(100 parts by weight), cobalt iodide hexahydrate (1.0 parts by weight) N, N'-hexamethylenebis (3,5-t-butyl-4-hydroxy-hydroxynnamamide) (0.5 part by weight) Parts by weight) of a nylon compound consisting of a thermosensitive element having the structure shown in FIG.
That is, a temperature detection line was created. Here, each component will be described. 1 is a polyester core yarn of 1,500 denier, 2, 4 is a 0.5% silver-containing copper electrode wire, 3 is a nylon thermosensitive layer, 5 is a polyester separating layer, and 6 is a polyester separating layer. Heat resistant vinyl chloride jacket. The thermistor B constant was about three times or more of 11,900 compared to the comparative example in which the thermosensitive layer was formed only with nylon 12.
0 (K), indicating that the polymer thermosensor of this example exhibited a durability of 2,000 hours or more against continuous 100 V half-wave conduction at 120 ° C., which was performed as a heat resistance life test.

[0013]

As is apparent from the above description, according to the present invention, the thermistor B constant of the polymer thermosensitive substance is increased about three times by using iron iodide and hindered phenol or naphthylamine in combination. However, even at high temperatures, the mechanical strength and the electrical properties are synergistically stabilized. Furthermore, by forming a temperature sensing element using the polymer temperature sensing element of the present invention, a temperature sensing element having high temperature detection sensitivity and excellent heat resistance reliability can be provided.

[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 thermosensitive element according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyester core yarn 2, 4 Electrode wire 3 Nylon thermosensitive layer 5 Polyester separation layer 6 Heat resistant vinyl chloride jacket

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H01C 7/00 H01C 7/00 X // H05B 3/56 H05B 3/56 B (56) References JP-A-59-213103 ( JP, A) JP-A-60-106104 (JP, A) JP-A-60-106106 (JP, A) JP-A-2-166159 (JP, A) JP-A-57-105990 (JP, A) JP-A-61-181106 (JP, A) JP-A-55-100693 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01K 7/16

Claims (7)

(57) [Claims] 1. A thermosensitive polymer comprising a polyamide composition comprising iron iodide and at least one selected from the group consisting of hindered phenol and naphthylamine. 2. The polymer thermosensor according to claim 1, wherein the iron iodide is at least one selected from iron iodide anhydride and iron iodide hydrate. 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 thermosensitive body according to claim 1, wherein the polyamide is at least one selected from the group consisting of the following (a) to (e). (A) polyundecaneamide (b) polydodecaneamide (c) N-alkyl-substituted amide copolymer of polyundecaneamide or polydodecaneamide (d) etheramide copolymer of polyundecaneamide or polydodecaneamide (e) Dimer acid-containing polyamide 7. The polymer thermosensitive body according to claim 1, wherein the polymer thermosensitive body is disposed between a pair of electrodes, and the physical properties of the polymer thermosensitive body between the two electrodes are determined. A thermosensitive element that detects a change due to temperature by using the two electrodes.