JPH0933361A - Polymer thermosensitive body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer thermosensitive body excellent in thermistor characteristic and long-term stability by forming the polymer thermosensitive body of a polyamide resin having a bending elasticity within a specified value range, and a thermoplastic phenol-contained polymer material having a softening point of a specified temperature or higher. SOLUTION: As the polyamide-based resin having a bending elasticity of 1000-7000kgf/cm<2> , a polyamide copolymer obtained by copolymerizing alkylether or hydrogenated dimer acid with nylon 11, nylon 12 or the like is used. As the thermoplastic phenolcontained polymer material having a softening point of 50 deg.C or higher, a special phenol resin using liquefied polybutadiene and phenol as starting materials is used. The polymer thermosensitive body is manufactured by fusing and kneading the polyamide-based resin having a bending elasticity of 1000-7000kgf/cm<2> with the thermoplastic phenol-contained polymer material having a softening point of 50 deg.C or higher with an extruder.

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 having excellent thermistor properties and long-term stable electrical properties.

[0002]

2. Description of the Related Art A polymer temperature sensor having a so-called thermistor characteristic in which impedance and dielectric constant change with temperature is used for detecting the temperature of an electric warming tool such as an electric blanket or an electric carpet. In addition to the thermistor characteristics, the characteristics required of such a polymer temperature sensor include stability of electric characteristics by heating and application of an electric field. Thermistor characteristics are thermistor B in temperature-impedance curve
The z constant and the long-term stability of the electrical characteristics can be evaluated by the change in impedance under the conditions of heating and AC application.

Nylon 12 has been widely recognized as a polymeric thermosensitive material because it has the lowest water absorption and melting point among polyamide resins and has thermistor characteristics.
A low water absorption rate of the temperature sensing element reduces the change in impedance during drying and water absorption, and a low melting point lowers the short circuit temperature in the thermal fuse function and enhances the safety function. In practice, additives are added to further enhance the thermistor properties of Nylon 12. As an additive, a phenol-containing substance is said to be suitable (Japanese Patent Publication No. 51-30958). However, the conventional phenol-containing substance is a liquid or a viscous substance, and although it has the effect of increasing the thermistor Bz constant by its action as a plasticizer, it has the drawback of lowering the long-term stability of impedance. It was

Therefore, the present inventor has conducted diligent studies to solve this drawback, and as a result, by combining a polyamide resin having a specific flexural modulus and a thermoplastic phenol-containing polymer substance, the thermistor characteristics and long-term stability are improved. The inventors have found that an excellent polymer temperature sensor can be obtained, and arrived at the present invention.

[0005]

Means for Solving the Problems That is, the present invention provides a polymer thermosensitive material comprising a polyamide resin having a flexural modulus of 1000 to 7000 kgf / cm ^{2 and} a thermoplastic phenol-containing polymer having a softening point of 50 ° C. or higher. It is the body.

The flexural modulus used in the present invention is 1000.
The polyamide resin of up to 7,000 kgf / cm ^{2 is} a polyamide copolymer obtained by copolymerizing nylon 11, nylon 12, nylon 610, nylon 612, nylon 1010, nylon 1212 and the like with alkyl ethers and hydrogenated dimer acids. Flexural modulus of 1000 to 70
The value is 00 kfg / cm ² . Flexural modulus is 100
If it is 0 kgf / cm ² or less, the long-term stability under heating and application of an electric field is poor, and the impedance as seen from the heater wire performance is too low. Conversely, 7,000 kfg / cm ²
If it exceeds, the thermistor Bz constant becomes small and lacks flexibility, so that it is not suitable as a polymer temperature sensitive material.

As the thermoplastic phenol-containing polymer substance having a softening point of 50 ° C. or higher used in the present invention, for example, a special phenol resin made of liquid polybutadiene and phenol (manufactured by Nippon Petrochemical Co., Ltd., Nippon Oil Special Phenolic Resin PP Type), special phenol resin made from dicyclopentadiene and phenol (Nippon Petrochemical, Nisseki special phenol resin DPP type), terpene-phenol copolymer (Yasuhara Chemical, Mighty Ace K125, YS Polystar, etc.), etc. However, the present invention is not limited to these.

The polymeric temperature sensor of the present invention has a flexural modulus of 10.
Polyamide resin of 00 to 7000 kgf / cm ² ,
It can be produced by melt-kneading a thermoplastic phenol-containing polymer substance having a softening point of 50 ° C. or higher with an extruder. The mixing ratio of each resin is 5 to 100 parts by weight, preferably 10 to 70 parts by weight, of the phenol-containing polymer with respect to 100 parts by weight of the polyamide resin. When the amount of the phenol-containing polymer is 5 parts by weight or less, the thermistor property is not sufficient, and when it is 100 parts by weight or more, the ductility of the composition is lowered and the extruding process of the heater wire is not easy.

[0009]

EFFECTS OF THE INVENTION The polymeric thermosensitizer of the present invention has a large thermistor Bz constant and is excellent in thermistor characteristics, has little change in impedance over time under heating and an electric field application, and is excellent in long-term stability. There is.

[0010]

The present invention will be described in detail below with reference to examples, but the invention is not limited thereto.

Example 1 Polyether ester amide "Daiamide E62" manufactured by Daicel Huls Co., Ltd. (flexural modulus of 3500 kg)
f / cm ² , melting point 172 ° C., equilibrium moisture content at 23 ° C. × 50% RH 0.7%) 100 parts by weight, terpene phenol copolymer “Mighty Ace K-125” manufactured by Yasuhara Chemical Co., Ltd. 20 parts by weight of a softening point of 80 ° C.) were mixed and melt-kneaded by a twin-screw extruder to form pellets. The flexural modulus (ASTM D-790 method) of the obtained polyetheresteramide composition was 4000 kgf /
The equilibrium water content was 0.55% at cm ² , melting point of 168 ° C., and 23 ° C. × 50% RH. This was press-molded into a 0.5 mm thick sheet to give a test piece.

The thermistor Bz constant at 100 Hz and 40 ° C. to 80 ° C. measured using an LCR meter 4274A manufactured by Yokogawa Hewlett Packard Co., was 4500, provided with a silver paint electrode. Also, 100
The rate of change in the volume specific impedance on the 50th day under the conditions of AC alternating current application and heating at 80 ° C. was 5.0%.

Example 2 Polyether ester amide "Daiamide E47" manufactured by Daicel Huls Co., Ltd. (flexural modulus 1400 kg
f / cm ² , melting point 160 ° C., equilibrium moisture content at 23 ° C. × 50% RH 0.5%) 100 parts by weight, hydrogenated terpene phenol copolymer “YS Polystar TH-130” manufactured by Yasuhara Chemical Co., Ltd. (Softening point 75 ° C) 20
Parts by weight were mixed, melt-kneaded and pelletized by a twin-screw extruder.

The flexural modulus of the resulting composition is 1000 k.
The equilibrium water content was 0.4% at gf / cm ² , melting point of 155 ° C. and 23 ° C. × 50% RH. When evaluated in the same manner as in Example 1, the thermistor Bz constants were 4300 and 80.
The rate of change in volume specific impedance at 50 ° C for 50 days is 4.
It was 6%.

Example 3 YS Polystar TH-13 manufactured by Yasuhara Chemical Co., Ltd.
Instead of 0, polybutadiene manufactured by Nippon Petrochemical Co., Ltd.
Phenolic resin "Special phenolic resin DPP600
Example 2 except that "M" (softening point 80 ° C) is used.
A composition was prepared and impedance measurement was carried out in the same manner as in. The flexural modulus of the obtained composition is 110.
0 kgf / cm ² , melting point 156 ° C., 23 ° C. × 50% RH
The equilibrium water content was 0.4%. When evaluated in the same manner as in Example 1, the thermistor Bz constant is 5000,
The rate of change in volume specific impedance on day 50 at 80 ° C. was 4.8%.

Example 4 Polyether ester amide "Daiamide E55" manufactured by Daicel-Huls KK (Flexural modulus 2100 kg
f / cm ² , melting point 165 ° C., equilibrium moisture content at 23 ° C. × 50% RH 0.6%) 100 parts by weight of Yasuhara Chemical Co., Ltd. terpene phenol bimolecular polymer “Y
20 parts by weight of “P90L” (melting point 70 ° C.) were mixed, melt-kneaded by a twin-screw extruder, and pelletized. The flexural modulus of the obtained composition is 1500 kgf / cm ² , and the melting point is 160.
Equilibrium moisture content at ℃, 23 ℃ × 50% RH 0.51%
Met. When evaluated in the same manner as in Example 1, the thermistor Bz constant was 5000, 80 ° C., and the rate of change in volume specific impedance on the 50th day was 3.4%.

Example 5 Hydrogenated dimer acid having 36 carbon atoms / hexane methylene diamine / lauryl lactam (nylon 12 content ratio: 50 wt.
%) So-called nylon 6.36 / 12 copolymer (flexural modulus 6000 kgf / cm ² , melting point 140 ° C.,
Equilibrium moisture content at 23 ° C x 50% RH 0.4%) 10
Terpene phenol copolymer "Mighty Ace K-125" manufactured by Yasuhara Chemical Co., Ltd. for 0 parts by weight
15 parts by weight (softening point: 80 ° C.) were mixed, melt-kneaded by a twin-screw extruder and pelletized. The flexural modulus of this composition is 6500 kgf / cm ² , melting point 138 ° C., 23 ° C. × 5
The equilibrium water content at 0% RH was 0.32%.

When evaluated in the same manner as in Example 1, the thermistor Bz constant was 4900, the rate of change in volume specific impedance on day 50 at 80 ° C. was 5.3%.

Comparative Example 1 Nylon 12 (flexural modulus 12000 kgf was used instead of "Daiamide E62" manufactured by Daicel Huls Co., Ltd.
/ Cm ² , melting point 178 ° C., equilibrium moisture content at 23 ° C. × 50% RH 0.7%), and a composition was obtained and evaluated in the same manner as in Example 1. The flexural modulus of the composition is 1500 kgf / cm ² , melting point 175 ° C.,
The equilibrium moisture content at 23 ° C. × 50% RH was 0.6%.

The thermistor Bz constant is 1700,
The change in volume specific impedance on day 50 at 80 ° C. was 5.1%.

Comparative Example 2 YS Polystar TH-130 manufactured by Yasuhara Chemical Co., Ltd.
A composition was obtained and evaluated in the same manner as in Example 2 except that 2-ethylhexyl ester of p-hydroxybenzoic acid (liquid at room temperature) was used instead of. The flexural modulus of the composition is 800 kgf / cm ² , melting point 158.
Equilibrium moisture content 0.45% at ℃, 23 ℃ × 50% RH
Met.

The thermistor Bz constant is 4600,
The rate of change in volume specific impedance on day 50 at 80 ° C. was 31%.

Claims (1)

[Claims] 1. A flexural modulus of elasticity of 1000 to 7000 kgf.
/ Cm ² Polyamide-based resin and a polymeric thermosensitizer comprising a thermoplastic phenol-containing polymeric substance having a softening point of 50 ° C or higher.