JP2743742B2 - Polymer thermosensor - 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. Further, Japanese Patent Publication No. Sho 60-48081 discloses a polyamide composition containing a phosphite as a thermal deterioration improving agent, and Japanese Patent Application Laid-Open No. 64-30203 discloses an ion conductive composition containing a copper deactivator and a phenolic antioxidant. 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.

[0004] It is an object of the present invention to provide a polymer thermosensor having a large impedance temperature dependence and excellent thermal stability.

[0005]

According to the present invention, there is provided a composition comprising a polyamide and an iodine metal compound and a phosphite compound having a phosphorus concentration of 3 to 20% by weight and a molecular weight of 200 to 50,000. Used as a temperature sensor.

[0006]

In general, a polymer thermosensor 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 polyamide composition of the present invention is used, the ion carrier properties of the iodine metal compound in the polymer thermosensor significantly increase the temperature dependence of impedance and are thermally stable. Further, diphosphite or tetraphosphite having a high molecular weight and a high phosphorus concentration, such as tetraphenyl dipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite and hydrogenated phenol A / pentaerythritol phosphite polymer, or The effects of the phosphite-based polymer's antioxidant properties and reduction rust-preventive action significantly reduce synergistic thermal degradation.
If the phosphorus concentration is low, this effect is low, and if it is too high, it is not practical. Although the phosphorus concentration is effective at 3-20% by weight,
Desirably, 5 to 15% by weight shows the best value. On the other hand, if the molecular weight is low, it tends to volatilize at high temperatures, and the effect is not persistent. On the other hand, if it exceeds 5,000, dispersion becomes difficult. Therefore, desirably 300 to 3,500 is practical. In the present invention, the combination of the perchlorate and the phosphite compound is not excluded from each other even if the actions overlap, but has a synergistic action when added. Therefore, it is considered that the thermal stability of the polymer thermosensor is improved, and the heat resistance of the thermosensor of the temperature sensor 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]

EXAMPLES The polyamide of the present invention has a hygroscopic property.
Nylon 12, N-alkyl substituted polyamide 1 with low content
1. Select polyetheramide or amide containing dimer acid
It is. The temperature dependence of the impedance of these polymers
As a conductivity-enhancing agent that enhances
Suitable for iodine metal compounds such as Kel and cobalt iodide
I do. In addition, it acts in synergy with the above iodine compounds to prevent oxidation
Phosphorous ester
Tetraphenyl dipropylene glycol dipho
Sphite (molecular weight 566, phosphorus concentration 10.9% by weight),
Tetraphenyltetra (tridecyl) pentaerythritol
Tetraphosphite (molecular weight 1,424, phosphorus concentration
8.7% by weight), hydrogenated bisphenol A / pentaerythri
Tall phosphite (molecular weight 2,500-3,100, phosphorus
Concentration 13.8% by weight). The composition ratio is nylon 10
All additives were 1 part by weight with respect to 0 parts by weight. Pheno
In the case of adding an aldehyde polycondensate of
Octyl ester oxybenzoate with good compatibility with lamide
Select the formaldehyde polycondensate and make it 15 parts by weight.
Was. The sample is compounded and kneaded with an extruder.
After heating, press the sheet about 70 × 70mm, 1mm thick
And silver-coated electrodes were provided on both sides thereof.
The temperature dependence of the impedance is
It was represented by the thermistor B constant. Heat resistance is 100 ℃
Initial impedance at 1600 hours at 150 ° C
Difference with impedance after air aging during heating
(ΔT _z). Thermic at 40-80 ° C
Star B constant is impedance Z at 40 ° C.₄₀and
Impedance Z at 80 ° C₈₀The result of measuring
And was calculated.

The results are shown in Tables 1 and 2.

[0009]

[Table 1]

[0010]

[Table 2]

As the iodine metal compound of the present invention, nickel iodide and cobalt iodide are used, which contribute to the improvement of temperature sensitivity and heat resistance. Also, as the phosphite,
Tetraphenyldipropylene glycol phosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, hydrogenated bisphenol A / pentaerythritol phosphite polymer with high molecular weight and excellent non-volatility and appropriate phosphorus concentration are used, and are stable against heat. It contributes to the improvement of the corrosion resistance and rust prevention effect. These combinations have even more synergistic effects. Also,
Among the aldehyde polycondensates of phenolic compounds, p-oxybenzoic acid octyl ester-aldehyde polycondensate and p-oxybenzoic acid isostearyl ester-formaldehyde polycondensate are excellent in compatibility and moisture resistance. P-dodecylphenol, p-chlorophenol, p-
Aldehyde polycondensates such as nonyl oxybenzoate may be used. 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.

For evaluation of the thermosensitive element, nylon 12 (10
0 parts by weight), nickel iodide (1 part by weight), and a pellet of a nylon compound composed of tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite (1 part by weight). Such a thermosensitive element, that is, a temperature detection line was prepared. here,
To explain each component, 1 is 1,500 denier polyester core yarn, 2, 4 is 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 the purpose of comparison, the thermistor B constant was about quadrupled to 12,800 (K) for a sample in which a thermosensitive layer was formed only with nylon 12, and this was about 5 times for a continuous 100 V energization at 130 ° C. The durability was more than 1,500 hours.

[0013]

As described above, according to the present invention, a combination of an iodine metal compound such as nickel iodide and cobalt iodide and a phosphite having an appropriate molecular weight and an appropriate phosphorus concentration are used. Even when the thermistor B constant is improved and the temperature is high, the mechanical strength and electrical characteristics over a long period of time are made to be synergistically stable, and the reliability of many practical applications can be improved. A polymer thermosensor having high temperature detection sensitivity and good heat resistance can be obtained.

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

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shuji Yamamoto 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-60-106104 (JP, A) JP-A-60 -106106 (JP, A) JP-A-61-181106 (JP, A) JP-B-60-48081 (JP, B2)

Claims (6)

(57) [Claims] 1. A high temperature thermosensitive polymer comprising a polyamide composition comprising a polyamide, an iodine metal compound and a phosphite compound having a phosphorus concentration of 3 to 20% by weight and a molecular weight of 200 to 5,000. body. 2. The polymer thermosensor according to claim 1, wherein the iodine metal compound is at least one selected from nickel iodide or cobalt iodide. 3. The phosphite compound is at least one selected from tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite, and hydrogenated phenol A pentaerythritol phosphite polymer. The polymer thermosensor according to claim 1, which is: 4. The polymer thermosensor according to claim 1, wherein the polyamide composition comprises an oxybenzoate / formaldehyde polycondensate. 5. The polymer thermosensor 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) Polyundecaneamide or N-alkyl-substituted amide copolymer of polydodecaneamide (d) Polyundecaneamide or N-alkyl-substituted amide copolymer of polydodecaneamide (E) Polyamide containing dimer acid 6. A thermosensitive element comprising the polymer thermosensitive element according to claim 1 disposed between a pair of electrodes.