JP2861641B2 - 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 Nanron 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. Japanese Patent Publication No. Sho 60-48081 discloses a polyamide composition containing a phosphite as a heat deterioration improving agent, and Japanese Patent Application Laid-Open No. Sho 64-30203 discloses a copper deactivator and a phenolic antioxidant. An example of a polyvinyl chloride heat-sensitive composition to which a perchlorate and a triazole-based copper deactivator are added is disclosed in JP-A-2-164005.

[0003]

However, nylon 12
Is excellent in that the moisture absorption rate is low, but it is difficult to use the temperature sensor as a temperature sensor because of its large fluctuation in temperature-sensitive characteristics due to humidity. Further, the modified polyamide disclosed in Japanese Patent Application Laid-Open No. 55-100693 has low temperature detection sensitivity due to small temperature dependence of impedance and is inferior in heat resistance stability. Therefore, in order to improve humidity resistance and temperature sensitivity, the Japanese Patent Publication No. 3-50
As disclosed in Japanese Patent Publication No. 401, a composition containing an aldehyde polycondensate of a phenolic compound has been proposed. 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 dependency and excellent thermal stability.

[0005]

According to the present invention, there is provided a polyamide comprising at least one perchlorate selected from the group consisting of imidazole and ammonium salts, a phosphorus concentration of 3 to 20% by weight and a molecular weight of 200 to 50,000. A composition in which the phosphite-based compound is mixed with at least two of triazole, phosphoric acid and a hindered phenol-based heat stabilizer is used as a thermosensitive body.

[0006]

In general, 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 thermal heater. The heat resistance 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, high-temperature oxidation such as heating of a wound electrode is performed by using at least two or more compounds among triazole, phosphoric acid, and a hindered phenol-based heat stabilizer in a polymer thermosensor. Markedly suppressed by its presence,
In addition, the ion carrier properties of the perchloric acid compound significantly increase the temperature dependence of the impedance, thereby making the impedance thermally stable. Moreover, 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 Due to the effects of the phosphite-based polymer's antioxidant properties and reduction rust-preventing action, heat deterioration is significantly and synergistically suppressed. If the phosphorus concentration is low, this effect is low, and if it is too high, it is not practical. Although an effect is obtained at a phosphorus concentration of 3 to 20% by weight, the best value is desirably obtained at a phosphorus concentration of 5 to 15% by weight. 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. By adding triazole, hindered phenol, and phosphoric acid in the presence of such a perchlorate and phosphite, rust prevention and oxidation prevention can be synergistically achieved. This combination is not alienated from each other even if the operations overlap, but has a synergistic effect when added. Therefore, it is considered that the contact state between the polymer thermosensitive body and the winding electrode is also improved, the thermal stability of the polymer thermosensitive body is improved, and the heat resistance 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. There is also an effect of increasing the temperature sensitivity by acting on the amide group.

[0007]

EXAMPLES As polyamides in the present invention, nylon 12, modified polyamide 11, polyether ald, and dimer acid-containing amide having low hygroscopicity were selected. As a conductivity-imparting agent for increasing the temperature dependence of the impedance of these polymers, imidazole-based and ammonium salt-based perchlorates having high thermal stability are suitable. As the imidazole compound, 2-heptadecenyl-2-imidazoline-
1-ethanol perchlorate was selected, and lauroylaminopropyldimethylhydroxyethylperchlorate and octyldimethylhydroxyethylammonium perchlorate were selected as ammonium salts. In addition, tetraphenyl dipropylene glycol diphosphite (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 / pentaerythritol phosphite (molecular weight: 2,50%)
0-3,100, phosphorus concentration 13.8% by weight). Further, in order to enhance the rust resistance of the copper wire and the heat resistance of the nylon temperature-sensitive composition, 3- (N-salicyloyl) is used as a triazole.
Amino-1,2,4-triazole was added. Phosphoric acid is used to improve rust resistance and heat resistance, and pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-) is used as hindered phenol to further enhance antioxidant properties.
4-Hydroxyphenyl) propionate] (CHI
"Irganox 101" made by BAGEIGY
0 "). The composition ratio was 100 parts by weight of nylon and all additives were 1 part by weight. In the example in which the aldehyde polycondensate of the phenol compound was added, an octyl oxybenzoate-formaldehyde polycondensate having good compatibility with the polyamide was selected, and the content was 15 parts by weight. As a specific example, a sample was prepared by mixing these components, kneading them with an extruder, and then using a hot press to about 70 × 70 mm and a thickness of 1 mm.
And a silver-coated surface electrode was provided on both sides of the sheet. Temperature dependence of impedance is 40 to 80 ° C
In the thermistor B constant. The thermal stability was as follows: initial impedance at 80 ° C and 1.0 at 150 ° C.
The temperature difference (ΔT _Z ) from the impedance after the heating air aging was performed for 00 hours. Incidentally, the thermistor B constant at 40 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 results are shown in (Table 1) and (Table 2).

[0009]

[Table 1]

[0010]

[Table 2]

As the perchloric acid compound of the present invention, lauroylamino-propyldimethyl-hydroxyethylperchlorate, octyldimethylhydroxyethylammonium perchlorate and 2-heptadecenyl-2-imidazoline-1-ethanol perchlorate are used. , Heat-sensitive,
Contributes to heat resistance. Further, as the phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, hydrogenated bisphenol A / pentaerythritol phosphite polymer is used, and heat resistance and rust prevention effect are used. Has contributed.

Further, 3- (N-salicyloyl) amino-1,2,4-triazole is used as a triazole, and contributes to improvement of rust resistance and heat resistance. Further, phosphoric acid contributes to improvement of rust resistance 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 heat-resistant oxidation prevention 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. These combinations are synergistically effective. In addition, aldehyde polycondensates of phenolic compounds include p-oxybenzoic acid octyl ester-aldehyde polycondensate and p-oxybenzoic acid isostearyl ester-formaldehyde polycondensate, which are excellent in compatibility and moisture resistance. However, in addition to the p-oxybenzoic acid alkyl ester, an aldehyde polycondensate such as p-dodecylphenol, p-chlorophenol, and nonyl p-oxybenzoate may be used. These are blended in an amount of 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 if it is more than 30 parts by weight, the properties of the matrix are significantly impaired.

[0013]

As described above, according to the present invention, an ammonium salt, an imidazole-based perchlorate, and a phosphite having an appropriate molecular weight and phosphorus concentration are used in combination, so that the thermistor B constant Synergistically stabilize mechanical strength and electrical properties over a long period of time, even at high temperatures, and synergistically impart rust resistance and heat resistance by using a combination of triazole, phosphoric acid, and hindered phenol. Therefore, the reliability of many practical applications can be improved. Therefore, a polymer thermosensor having high temperature detection sensitivity and good heat resistance can be obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01K 7/16 G01K 7/16 C H01L 51/00 H01L 29/28 (72) Inventor Naoko Yanagida 1006 Odakadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masahiko Ito 1006 Kazuma Odoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-56-71211 (JP, A) Patent 281207 (JP, C1) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01C 7/04-7/22

Claims (4)

(57) [Claims] 1. A polyamide comprising at least one perchlorate selected from the group consisting of an imidazole compound and an ammonium salt compound, a phosphorus concentration of 3 to 20% by weight and a molecular weight of 200 to 5.0%.
A thermosensitive polymer comprising a polyamide composition comprising a phosphite compound of No. 00 and at least two of triazole, phosphoric acid, and a hindered phenol heat stabilizer. 2. The phosphite-based compound is at least one selected from tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite or hydrogenated phenol A pentaerythritol phosphite polymer. The polymer thermosensor according to claim 1, which is one kind. 3. The polymer thermosensor according to claim 1, wherein the polyamide composition comprises a polycondensate of oxybenzoate and formaldehyde. 4. 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) N-alkyl-substituted amide copolymer of polyundecaneamide or polydodecaneamide (d) etheramide copolymer of polyundecaneamide or polydodecaneamide (e) Polyamide containing dimer acid