JPS6048081B2 - polymer thermosensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature sensing element used in a flexible linear temperature sensing wire used in a temperature sensing device for controlling the temperature of a heating element such as an electric blanket or an electric carpet. It is something.

Until now, the polymer temperature-sensitive materials used for this type of purpose are polymer compositions made by adding a small amount of a substance that provides ionic conductivity, such as a surfactant, to a flexible resin such as soft polyvinyl chloride. things were being used.

However, since the conductive carrier of these compositions is an ionic substance, polarization occurs when a direct current electric field is applied, so that they cannot be used as a temperature sensitive body of a thermal heater, which is the object of the present invention. Further, as seen in Japanese Patent Application Laid-open No. 51-1269, attempts have been made to suppress the polarization phenomenon by adding phosphoric acid, boric acid, phosphorus, or boron compounds.

However, since these compounds have high hygroscopicity, polyamide compositions to which these compounds are added have a significant drop in impedance under high humidity, making it difficult to put them into practical use. As a similar example, Japanese Patent Publication No. 51-42314 discloses a composition in which a phosphoric acid ester into which a hydroxyphenyl group has been introduced is blended with polyamide to improve moisture resistance.

However, the polyamide compositions blended with phosphorus or boron compounds or phosphoric acid esters in both of the above compositions completely lose the flexibility and flexibility required for the thermosensor of the present invention after being left in a high-temperature atmosphere. I end up. The present invention eliminates these conventional drawbacks and provides a polymer thermosensitive material that has low polarization and hygroscopicity, high temperature detection function, and does not suffer from deterioration in flexibility due to thermal deterioration.

The moisture sensitive material in the present invention is a composition in which phosphites are blended with polyamide.

Here, phosphite esters collectively refer to the following compounds. (1) Compounds represented by the general formula (RO)3P ・(2) Phosphorous acid in which groups represented by the general formula 'R2α-P-OR are linked by a carbon atom or a bonding chain containing a carbon atom i Esthenore (3
) Polymer of the form represented by the general formula (41 In the compound represented by the general formula), R,,R, to R5 are an alkyl group, *phenyl group, or a phenyl group substituted with an alkyl group, and R゛ indicates a group with one extra bond in the above group or a case where nothing is bonded to the oxygen atom.

Specific examples of phosphite esters in each of the above groups include:
Examples include: (1) Triphenylphosphite, tris(2-elhexyl)phosphite, 12) Tetraphenyldipropylene glycol diphosphite, tetraphenyltetra(tridecyl)pentaerythritortetraphosphite, (3) Hydrogenated bisphenol A phosphite poly 14) Diphenyl hydrogen phosphite and dilauryl hydrogen phosphite. All of these have excellent polarization resistance, heat deterioration resistance, and moisture resistance.

Good results are obtained when the amount of phosphites is 0.1 part by weight based on 1 part by weight of polyamide, and sufficient resistance is obtained when the amount is 0.1 part by weight or less. It is not possible to impart properties such as polarizability, moisture resistance, high temperature sensing function, or heat deterioration resistance, and conversely, if the amount exceeds 10 parts by weight, sufficient compatibility with polyamide will be impaired. Both are undesirable. Also,
It goes without saying that plasticizers, fillers, additives that impart thermistor properties, etc. commonly used in polyamides can be appropriately blended into these compositions.
The structure of the thermal heater which is the object of the present invention is as shown in the figure.

That is, the inner sensing wire 2 wound around the heat-resistant core thread 1 also serves as a heater, and catches signals between it and the outer sensing wire 3. 4 is a polymer temperature sensitive body interposed between the detection lines 2 and 3, and 5 is an outer cover.

For example, a direct current or a half-wave rectified wave is applied to the heater to heat the heater. Temperature detection is performed by applying an alternating current voltage between both sensing wires to obtain a temperature signal. Next, examples of the present invention will be described.

Example 1 Tris (2
-0.5 parts by weight of (ethylhexyl) phosphorite is added, extruded into cut shapes using a press molding machine, and then pelletized.

The pellets are dried and passed through a wire-making extruder to produce a temperature-sensing heater. Example 2 2 parts by weight of Tet roughenyl dipropylene glycol diphosphorite was blended with 10 parts by weight of nylon 12 powder, and a temperature sensing heater was prepared in the same manner as in Example 1.

Example 3 0.1 part by weight of uryl hydrogen phosphorite was added to 10 parts by weight of nylon 12 powder,
A temperature detection heater is made in the same manner.

Comparative Example 1 1 part by weight of phosphoric acid was blended with 10 parts by weight of powder of nylon 12, and a temperature sensing heater was similarly prepared. Ru.

Comparative Example 2 Trisu P for 10 parts of powder of Nylon 12
- 1 part of hydroxyphenyl phosphate is blended to prepare a temperature sensing heater.

Comparative Example 3 A nylon 1-layer product was used to similarly detect temperature.

ゝ The following table shows a comparison of the various characteristics of the temperature sensitive bodies of each of the above examples. Note that the thermistor B constant is the thermistor B constant of impedance from 30C to 600C.

The heat resistance is 30CjIf1 at 120°C, and the impedance ratio before and after applying a DC electric field recommended by 5VI (1205C
(ratio of measured values). Moisture resistance is 45°C
It is expressed as the impedance ratio (comparison at room temperature) to the absolute dry state after being left in an atmosphere with a relative humidity of 95% for 7 hours, and the flexibility is measured after leaving a cut with a diameter of 2 mm in a thermostat at 120°C for 3 hours. , 90 bending tests were carried out, and the number of bends was expressed as the number of bends until cutting. As is clear from these results, the temperature sensitive body of the present invention has better moisture resistance, polarization resistance, heat deterioration resistance, and temperature detection function (larger value of thermistor B constant) than those made from nylon. Excellent, with greatly improved moisture resistance and heat deterioration resistance compared to nylon 1 compositions containing phosphoric acid, and markedly improved heat deterioration resistance compared to compositions containing Tory P-hydroxyphenyl phosphate. I understand that.

As described above, the temperature sensitive material of the present invention has excellent electrical and mechanical properties.

[Brief explanation of the drawing]

The drawing shows the configuration of the temperature sensitive heater.

Claims (1)

[Scope of Claims] 1. A polymer thermosensitive material comprising a polyamide composition containing phosphite esters. 2. The polymer thermosensitive material according to claim 1, wherein the phosphite ester is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polyamide.