JPH07142213A - Polymer temperature sensor and temperature sensor using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a polymer temperature sensor used for a flexible temperature sensor such as an electric warming tool or a temperature sensitive heater, which has excellent temperature sensing characteristics and heat resistance stability, and a temperature sensing element using the same. The purpose is to provide. [Structure] The polymer temperature sensitive material is composed of a polyamide composition in which at least zinc iodide and at least one selected from hindered phenol and naphthylamine are mixed with polyamide, and the temperature sensing property and excellent heat current stability are obtained. Sex is obtained. Further, the temperature sensing element using this polymer temperature sensing element has a structure in which the polymer temperature sensing element 4 is disposed between the pair of electrode wires 1 and 3.

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 and a temperature sensitive heater, and a temperature 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 the polymer temperature sensitive material include nylon 12 and modified polyamide 11 (ATO-CHI) disclosed in JP-A-55-100693.
A polyamide composition such as a product manufactured by MIE Co., Ltd. under the trade name of “Rilsan N nylon”) is used, and its temperature change such as capacitance, resistance value or impedance is used to fulfill the function of a temperature sensor.

Further, Japanese Patent Publication No. 60-48081 discloses a polyamide composition to which a phosphite is added as a heat deterioration improving agent, and Japanese Patent Application Laid-Open No. 64-30203 discloses a copper deactivator and a phenolic antioxidant. Examples of added ion conductive heat sensitive compositions are disclosed.

[0004]

Nylon 12 is excellent in that it has a low hygroscopicity, but it is difficult to put it into practical use as a temperature sensor because the temperature-sensitive characteristics vary greatly depending on humidity. Further, in the modified polyamide 11 described in JP-A-55-100693, the temperature dependence of impedance is small, so that the temperature detection sensitivity is low and the heat stability is poor. Therefore, in order to improve the humidity resistance and the temperature sensitivity, Japanese Patent Publication No. 3-5040
A composition containing an aldehyde polycondensate of a phenolic compound as disclosed in Japanese Patent Publication No. 1 has been proposed.

However, these all have problems that the temperature dependence of impedance is low and the thermal stability for a long period of time is insufficient.

The present invention solves the above-mentioned conventional problems, and provides a polymer temperature sensor having a large temperature dependence of impedance and excellent thermal stability, and a temperature sensor using the same. With the goal.

[0007]

In order to achieve the above object, the polymer thermosensitizer of the present invention comprises a polyamide compounded with at least zinc iodide and at least one compound selected from hindered phenol and naphthylamine. The thermosensitive element of the present invention is constituted by disposing the polymer thermosensor between a pair of electrodes.

[0008]

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 of the present invention is used,
The ion carrier property of zinc iodide in the polymer thermosensitizer markedly enhances the temperature dependence of impedance and forms a zinc complex in the amide group to enhance the electrical stability. Moreover, the antioxidant property of hindered phenol or naphthylamine makes it thermally stable.

The combination of zinc iodide and the hindered phenol or naphthylamine in the present invention does not become alienated from each other even if the actions overlap, but they have an additive synergistic action. Therefore, 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 remarkably increased.

Further, by blending an aldehyde polycondensate of a phenol compound, a strong anti-moisture absorption 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.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A polymer temperature sensor and a temperature sensor using the same according to an embodiment of the present invention will be described below with reference to the drawings. In this embodiment, as the polyamide, nylon 12 having a low hygroscopic property, nylon 12-nylon 40 copolymer, N-alkyl-substituted polyamide 11, polyether amide, or dimer acid-containing polyamide is selected, and these are used alone or at a certain level. Used in combination in proportion.

Zinc iodide, which has high thermal stability, was used as a conductivity-providing agent (sensitizer) for increasing the temperature dependence of impedance of these polymers.

Further, as a hindered phenol as an antioxidant for improving the antioxidant property and the thermal stability, 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'-
Hexamethylene bis (3,5-di-t-butyl-4-hydroxy-hydroxynamamide) (molecular weight 637.
0), 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 (molecular weight 741) was selected, and phenyl-α-naphthylamine (molecular weight 404) was selected as the naphthylamine.

In the case where an aldehyde polycondensate of a phenol compound was further added, an oxybenzoic acid octyl ester-formaldehyde polycondensate having good compatibility with polyamide was selected.

Samples were prepared by blending these, kneading them with an extruder, and then hot-pressing them to about 70 mm × 70 mm, thickness 1 mm.
Was formed into a sheet and the electrodes coated with silver were provided on both sides of the sheet. The temperature dependence of impedance is represented by the thermistor B constant at 40 ° C to 80 ° C.

The thermal stability was expressed as a temperature difference (ΔT _z ) between the initial impedance at 100 ° C. and the impedance after 100 V half-wave energization at 100 ° C. for 1,000 hours. The thermistor B constant at 40 ° C to 80 ° C is impedance Z _{40 at} 40 ° C.
And the impedance Z ₈₀ at 80 ° C. was measured and calculated based on the result.

Table 1 shows the contents and results of Examples 1 to 8 and Comparative Examples 1 and 2 showing the composition and characteristics of the above-mentioned polymeric thermosensitive materials.

[0019]

[Table 1]

The zinc iodide anhydride or zinc iodide dihydrate used as the sensitizer in this example is the thermistor B.
It contributes to the improvement of the constant.

These zinc iodides are mixed in an amount of 0.01 to 30 parts by weight based on 100 parts by weight of polyamide, and 0.0
If it is less than 1 part by weight, the sensitizing property and 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.

Triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] or pentaerythrityl-tetrakis [as a hindered phenol used as an antioxidant. 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] or N, N'-
Hexamethylene bis (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 contribute to the improvement of heat resistance.

The combination of these antioxidants further exerts a 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 blended in an amount of 5 to 30 parts by weight with respect to 100 parts by weight of 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), zinc iodide (1.0 parts by weight), N, N'-
Pellets of a polyamide composition composed of hexamethylene bis (3,5-t-butyl-4-hydroxy-hydroxynamamide) (0.5 parts by weight) were prepared and the pellets were used as shown in FIG. A temperature sensitive element, that is, a temperature detection line was created.

The structure of this temperature sensitive element is such that a 1,500 denier polyester core thread 2 wound with a copper electrode wire 1 containing 0.5% silver and a polyamide feeling obtained by winding a copper electrode wire 3 containing 0.5% silver. It is coated with a warm layer 4, and the periphery thereof is further coated with a polyester separation layer 5 and a vinyl chloride jacket 6.

That is, a temperature sensitive element is constructed by disposing a polymer temperature sensitive body between a pair of electrodes. The thermistor B constant of this temperature sensitive element is about the same as the thermistor B constant of 3,500 (K) of the prototype of Comparative Example 1 shown in Table 1 in which the polyamide temperature sensitive layer 4 is formed of only nylon 12 for comparison. It showed 10,400 (K), which was three times as high, and showed durability of 2,000 hours or more against continuous 100 V half-wave energization at 120 ° C. performed as a heat resistance life test.

[0028]

As is apparent from the above description, according to the polymer temperature sensor of the present invention and the temperature sensor using the same,
By using at least zinc iodide and hindered phenol or naphthylamine in combination with polyamide, it is possible to improve the thermistor B constant and synergistically stabilize mechanical strength and electrical properties for a long period of time even at high temperature, and to obtain practical use. Reliability in general applications can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a temperature-sensitive element using a polymer temperature sensor according to an embodiment of the present invention.

[Explanation of symbols]

 1,3 Electrode wire 2 Polyester core yarn 4 Polyamide temperature sensitive layer (polymer temperature sensitive body) 5 Polyester separation layer 6 Vinyl chloride jacket

Claims (7)

[Claims] 1. A polymer temperature sensor having a polyamide composition in which a polyamide is blended with at least zinc iodide and at least one selected from hindered phenol and naphthylamine. 2. The polymeric thermosensitizer according to claim 1, wherein the zinc iodide is at least one selected from zinc iodide anhydride and zinc iodide hydrate. 3. The hindered phenol is 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-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,
The polymeric thermosensitizer according to claim 1 or 2, which is at least one selected from 10-tetraoxaspiro [5,5] undecane. 4. The 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. Temperature sensitive body. 5. The polymer temperature sensor according to claim 1, wherein the polyamide composition contains an oxybenzoic acid ester / formaldehyde polycondensate. 6. The polyamide comprises the following (a) to (f):
2. At least one selected from the group consisting of:
6. The polymeric temperature sensor according to any one of 1 to 5. (A) Polyundecane amide (b) Polydodecanamide (c) Polyamide containing linear saturated hydrocarbon C ₁₂ or more and copolymer thereof (d) Polyundecane amide or N-alkyl substituted polyamide copolymer of polydodecane amide (E) Polyundecanamide or Polydodecanamide Polyetheramide Copolymer (f) Dimer Acid-Containing Polyamide 7. A polymer temperature sensor having a polyamide composition in which polyamide is mixed with at least zinc iodide and at least one selected from hindered phenol and naphthylamine is provided between a pair of electrodes. The temperature sensitive element.