JPH0729705A - Polymer temperature sensor and thermosensitive element using the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to a temperature-sensitive body used for a flexible temperature sensor such as an electric warming tool or a temperature-sensitive heater, and is a polymer temperature-sensitive having excellent temperature-sensitive characteristics and heat resistance stability. Intended to provide the body. [Structure] A composition comprising a polyamide and nickel iodide or cobalt iodide and at least one selected from hindered phenols and naphthylamines is provided, and temperature detection and excellent heat conduction stability are obtained. .

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 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 is 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 its temperature change such as capacitance, resistance value or impedance is used to fulfill the function of a temperature sensor. Further, in JP-B-60-48081, a polyamide composition in which a phosphite is added as a heat deterioration improving agent, and in JP-A-64-30203, ion conduction in which a copper deactivator and a phenolic antioxidant are added. Examples of heat-sensitive compositions are disclosed.

[0003]

Nylon 12 is excellent in that it has a low moisture absorption rate, but it is difficult to put it into practical use as a temperature sensor, because its temperature-sensitive characteristics vary greatly depending on humidity. 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 problems that the temperature dependence of impedance is low and the thermal stability for a long period of time is insufficient.

It is an object of the present invention to provide a polymer temperature sensitive body having a large impedance temperature dependency and excellent thermal stability.

[0005]

According to the present invention, a composition obtained by blending polyamide with nickel iodide or cobalt iodide and at least one selected from hindered phenol and naphthylamine is used as a temperature sensitive body.

[0006]

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 electrode. When the polyamide composition having the above-mentioned constitution is used, the temperature dependence of the impedance is remarkably increased by the ionic carrier property of nickel iodide in the polymer thermosensitizer, and a nickel complex band is formed in the amide group to stabilize the electric current. Increase. Moreover, the antioxidant property of hindered phenol or naphthylamine makes it thermally stable. The combination of nickel iodide or cobalt iodide with the hindered phenol or naphthylamine in the present invention is not excluded from each other even if the actions overlap, but they have an additive action and have a synergistic action. Therefore, it is considered that the thermal stability of the polymer temperature sensitive body 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 instead of water molecules in polyamides to reduce hygroscopicity 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.

[0007]

【Example】

Example 1 An example of the present invention will be described below. In the first embodiment of the present invention, as the polyamide, nylon 12 having low hygroscopicity and N-alkyl-substituted polyamide 1 are used.
1. Polyether amide and amide containing dimer acid were selected. Nickel iodide, which has high thermal stability, was also used as a conductivity-imparting agent that increases the temperature dependence of the impedance of these polymers. In addition, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate (molecular weight 586.
8), pentaerythrityl-tetrakis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate (molecular weight 1177.7), N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-
Hydroxynnamamide) (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),
Phenyl-α-naphthylamine (molecular weight 404) was selected as the naphthylamine. Further, in the example in which an aldehyde polycondensate of a phenol compound was added, an oxybenzoic acid octyl ester-formaldehyde polycondensate having a good compatibility with polyamide was selected and set to 15 parts by weight. A sample was prepared by blending these, kneading them with an extruder, and then forming into a sheet of about 70 × 70 mm and a thickness of 1 mm with a heating press, and providing silver-coated surface electrodes on both sides thereof. The temperature dependence of impedance is represented by the thermistor B constant at 40 to 80 ° C. Further, the heat resistance stability was represented by a temperature difference (ΔT _Z ) between the initial impedance at 100 ° C. and the impedance after 100 V half-wave energization at 80 ° C. for 1,000 hours. The thermistor B constant at 40 to 80 ° C was calculated based on the results of measuring the impedance Z _{40 at} 40 ° C and the impedance Z ₈₀ at 80 ° C.

The results are shown in Table 1.

[0009]

[Table 1]

As the sensitizer of the present invention, anhydrous nickel iodide or nickel iodide hexahydrate is used, which contributes to the improvement of the thermistor B constant. 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-t-butyl-
4-hydroxy-hydroxynamamide) or 3,9
-Bis {2- [3- (3-t-butyl-4-hydroxy5-methylphenyl) propionyloxy] -1,1-
Dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane and naphthylamine are used and contribute to the improvement of heat resistance. These combinations have a further synergistic effect. In addition, the aldehyde polycondensates of phenolic compounds include p-oxybenzoic acid octyl ester-aldehyde polycondensates and p-
The oxybenzoic acid isostearyl ester-formaldehyde polycondensate is excellent in compatibility and moisture resistance, but in addition to the p-oxybenzoic acid alkyl ester, p-dodecylphenol, p-chlorophenol, nonyl p-oxybenzoate is used. It may be an aldehyde polycondensate such as an ester. These are mixed in 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 30
If the amount is larger than the amount by weight, the properties of the composition are significantly deteriorated.

Nylon 12 (10
0 parts by weight), nickel iodide hexahydrate (1.0 parts by weight)
N, N'-hexamethylenebis (3,5-t-butyl-
Pellets of a nylon blend consisting of 4-hydroxy-hydroxynamamide) (0.5 part by weight) were prepared, and the pellets were used to prepare a thermosensitive element, that is, a temperature detection line as shown in FIG. Here, each component will be described. 1 is 1,500 denier polyester core yarn, 2 and 4 are 0.5% silver-containing copper electrode wires, 3 is nylon temperature sensitive layer, 5 is polyester separation layer, and 6 is It is a heat resistant vinyl chloride jacket. For comparison, the thermistor B constant was 12,000 (K), which was about 3 times or more that of the prototype in which the temperature sensitive layer was formed only with nylon 12, and the continuous 100 V and half at 120 ° C. was performed as a heat resistance life test. It showed a durability of more than 2,000 hours against wave current.

(Embodiment 2) In the second embodiment of the present invention,
As a polyamide, nylon 12, N with low hygroscopicity
-Alkyl-substituted polyamide 11, polyether amide,
An amide containing dimer acid was selected. As a conductivity-imparting agent that enhances the temperature dependence of impedance of these polymers,
Cobalt iodide, which has high thermal stability, was used. Further, as hindered phenols, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate (molecular weight 586.8), penta is used as a hindered phenol in order to improve the antioxidant property and the thermal stability. 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-hydroxynamamide)
(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 404) was selected as the naphthylamine. Further, in the example in which an aldehyde polycondensate of a phenol compound was added, an oxybenzoic acid octyl ester-formaldehyde polycondensate having a good compatibility with polyamide was selected and set to 15 parts by weight. The sample was blended with these, kneaded with an extruder, and then heated to about 70 × 70.
The sheet was formed into a sheet having a thickness of 1 mm and a thickness of 1 mm, and silver coated surface electrodes were provided on both sides of the sheet. The temperature dependence of impedance is represented by the thermistor B constant at 40 to 80 ° C.
Further, the heat resistance stability was represented by a temperature difference (ΔT _Z ) between the initial impedance at 100 ° C. and the impedance after 100 V half-wave energization at 80 ° C. for 1,000 hours.
The thermistor B constant at 40 to 80 ° C was calculated based on the results of measuring the impedance Z _{40 at} 40 ° C and the impedance Z ₈₀ at 80 ° C.

The results are shown in Table 2.

[0014]

[Table 2]

As the sensitizer of the present invention, anhydrous cobalt iodide or cobalt iodide dihydrate, cobalt iodide 6
A hydrate is used and contributes to the improvement of the thermistor B constant. As an antioxidant, hindered phenol such as triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] or pentaerythrityl-tetrakis [3-] is used.
(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] -1,1-dimethylethyl} -2,
4,8,10-Tetraoxaspiro [5,5] undecane and naphthylamine are used and contribute to the improvement of heat resistance. These combinations have a further synergistic effect. 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 properties of the composition are significantly impaired.

Nylon 12 (10
0 parts by weight), cobalt iodide hexahydrate (1.0 parts by weight)
N, N'-hexamethylenebis (3,5-t-butyl-
Pellets of a nylon blend consisting of 4-hydroxy-hydroxynamamide) (0.5 part by weight) were prepared, and the pellets were used to prepare a thermosensitive element, that is, a temperature detection line as shown in FIG. Here, each component will be described. 1 is 1,500 denier polyester core yarn, 2 and 4 are 0.5% silver-containing copper electrode wires, 3 is nylon temperature sensitive layer, 5 is polyester separation layer, and 6 is Thermistor B constant is 11,900 (K), which is about 3 times or more, as compared with the heat-resistant vinyl chloride jacket, which is a prototype in which the temperature-sensitive layer is formed only by nylon 12, for comparison. It showed a durability of 2,000 hours or more with respect to continuous 100 V half-wave energization at 120 ° C.

[0017]

As described above, according to the present invention, the combined use of nickel iodide or cobalt iodide and hindered phenol or naphthylamine improves the thermistor B constant and keeps the mechanical properties for a long time even at high temperature. Strength and electrical properties can be made synergistically stable to improve reliability in many practical applications.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a temperature detection heater wire using a temperature sensing element.

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 77/00 LQT G01K 7/16 S 9207-2F // H05B 3/56 B 7715-3K

Claims (9)

[Claims] 1. A polymer thermosensitizer comprising a polyamide composition in which nickel iodide and at least one selected from hindered phenol and naphthylamine are mixed with polyamide. 2. The polymer thermosensitizer according to claim 1, wherein the nickel iodide is at least one selected from nickel iodide anhydride and nickel iodide hydrate. 3. A polymer thermosensitizer comprising a polyamide composition in which polyamide is blended with cobalt iodide and at least one selected from hindered phenol and naphthylamine. 4. The polymeric thermosensitizer according to claim 3, wherein the cobalt iodide is at least one selected from anhydrous cobalt iodide and hydrated cobalt iodide. 5. A hindered phenol is triethylene glycol-his [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 polymer thermosensitizer according to claim 1 or 3, which is at least one selected from 1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane. 6. The polymer thermosensitive material according to claim 1, wherein the naphthylamine is at least one selected from phenyl-α-naphthylamine and N′N-di-β-naphthyl-p-phenylenediamine. body. 7. The polyamide composition comprises an oxybenzoic acid ester / formaldehyde polycondensate.
Alternatively, the polymer temperature sensor according to claim 3. 8. The polymeric temperature sensitive body according to claim 1 or 3, wherein the polyamide is at least one selected from the group consisting of the following (a) to (e). (A) Polyundecane amide (b) Polydodecane amide (c) N-alkyl-substituted amide copolymer of polyundecane amide or polydodecane amide (d) Ether amide copolymer of polyundecane amide or polydodecane amide (e) Polyamide containing dimer acid 9. A heat-sensitive element comprising the polymer temperature sensor according to claim 1 disposed between a pair of electrodes.