JPS639362B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polymeric temperature sensitive body made of a specific polyamide resin composition, particularly to the temperature resistance value of a heat sensitive material in a device that controls temperature using a capacitance component as one control factor. The present invention relates to a polymer temperature sensitive body with improved impedance or capacitance behavior. Polymer thermosensitive materials are often used as constituent materials for electric wires for heating elements such as electric blankets and electric carpets. (2) small fluctuations in electrical properties depending on the environment in which the heating element is used, especially humidity; (3) mechanical strength and electrical properties within the normal operating temperature range. (4) It has a clear melting point to cope with abnormal temperature rises. Polymer materials known to have been used as thermosensors include polyvinyl chloride, cellulose esters, polyamides, copolymers of acrylic esters and acrylonitrile (Japanese Patent Publication No.
Publication No. 1627, Special Publication No. 7635, Special Publication No. 1976-
Publication No. 14179). An example of application of a thermosensitive temperature control line or surface using these polymeric materials is shown in FIG. It essentially consists of an insulating material 1, a core wire 2, a polymer temperature sensitive body 3, a signal wire 4, and a heater wire 5. With this configuration, the temperature can be detected and controlled along the heating wire by utilizing the fact that the electrical characteristics of the polymer thermosensitive element 3, that is, the resistance value, impedance, or capacitance, change depending on the temperature. It is something. Among the polymer materials mentioned above that are known as polymer thermosensors, polyamide resin has
Since it has excellent mechanical properties, heat resistance, moldability, etc., it is often used as a polymer thermosensitive material. Furthermore, polyamide resin is a crystalline polymer and has a distinct melting point compared to other resins, making it possible to cope with abnormal temperature rises.
In other words, when a polyamide resin is used for the polymer thermosensitive material shown in Figure 1, the melting point of the polyamide resin is around 200°C, and if the temperature of the exothermic wire exceeds the melting point due to abnormal temperature rise, the above-mentioned The polymer temperature sensitive body melts, causing a short circuit between the heating wire 5 and the signal wire 4 shown in FIG. 1, allowing the safety device to be activated. In order to make the rate of change in resistance, impedance, or capacitance due to temperature more noticeable in the operating temperature range of a polymer thermosensitive material, for example, as shown in Japanese Patent Publication No. 35-14179, a polymer thermosensitive material There is a description that a polymer temperature sensitive composition is produced by blending an ionic surfactant, that is, a cationic or anionic surfactant, with a polyvinyl chloride or polyamide resin. However, these ionic surfactants have poor heat resistance, and polyvinyl chloride has poorer heat resistance than polyamide resin, and unlike polyamide resin, it does not have a clear melting point and cannot cope with abnormal temperature rises. It has its drawbacks. Further, when an ionic surfactant is blended with a well-known polyamide resin such as nylon 6 or nylon 66, it cannot be blended because the ionic surfactant has poor heat resistance. In other words, the special public official
Although it is possible to add surfactants such as stearyldimethylbenzyl ammonium chloride described in Publication No. 14179 to polyamide resin to increase the temperature change in its electrical properties, it is possible to increase the temperature change in the electrical properties of polyamide resin. It is almost impossible to even knead it into polyamide resin because its heat resistance is too poor. In addition, nylon 6, a typical polyamide resin, as described in Japanese Patent Publication No. 26-1627,
Alternatively, in the case of nylon 66, etc., its water absorption ability is too high for a heat-sensitive material, so a film that provides moisture resistance such as polyvinyl chloride is formed on the outermost layer, as is already known as a heat-sensitive wire for electric blankets. Even so, it is difficult to obtain substantially complete moisture proofing. For this reason, nylon 6 or nylon 66
The control temperature point of a heat sensitive body using a heat sensitive body varies considerably depending on the environmental conditions in which it is placed. In other words, nylon 6 or nylon 66 has too high water-absorbing ability, and its electrical properties vary significantly depending on the environmental conditions in which it is used, so it is practically impossible to use it as a heat-sensitive wire for electric blankets, electric carpets, etc. be. This disadvantage increases synergistically when water-absorbing additives such as surfactants are added. Currently, the best polymer thermosensor is
Nylon 11, nylon 12 or nylon 11, nylon 12, nylon with electrical property modifiers
6.12, nylon 12.12 and PVC are known. However, when using nylon 11, nylon 12, etc. alone, the temperature change in electrical properties is small and the absolute value of the electrical properties is large, creating difficulties in terms of electrical circuits (controllers). On the other hand, with nylon 11, nylon 12, and PVC whose electrical properties have been improved by adding additives, the above-mentioned problems are solved, but a major new problem arises in that DC polarization phenomenon occurs significantly. In view of the above-mentioned points, the present inventors have made extensive studies and found that at least one
at least one polyamide prepared from (a) an ω-aminocarboxylic acid or lactam, (b) an α,ω-dihydroxy-polytetrahydrofuran having a molecular weight between 160 and 3000, and (c) a dicarboxylic acid. It was discovered that a mixture of 5 to 80 wt % of the component and 95 to 20 wt % of the component in a mixture with an ether ester amide makes an excellent polymer thermosensitive material, and the present invention has been achieved. Components used are ω-aminocarboxylic acids or lactams with a number of carbon atoms greater than 10, such as polylaurinlactams or polyundecanoic acid amides, in particular homopolyamides of polylaurinlactams. The second component, polyether ester amide (), is produced, for example, by the method disclosed in JP-A-119997-1983. This is carried out by hydrolytic polycondensation under elevated pressure, in which polyamide-forming starting components include, for example, ω-aminoundecanoic acid, in particular laurinlactam, as diol component molecular weight 160-3000; Especially 300-2200, especially
500 to 1200), as dicarboxylic acids, in particular dicarboxylic acids having from 4 to about 30 carbon atoms, preferably dodecanedicarboxylic acid, hexahydroterephthalic acid, terephthalic acid and/or Isophthalic acid is used respectively. The product of the present invention has a larger temperature coefficient of electrical characteristics than conventionally known polymeric temperature sensitive bodies, and is also more flexible than conventional products. Therefore, as a polymer thermosensitive material, it has high temperature control accuracy and excellent bending processability. The characteristics as a polymer thermosensitive material are the ratio of polyamide () to polyether ester amide (),
It can be varied depending on the ratio of the polyether ester component to the polyamide component in the polyether ester amide () and the type of polyether ester component in the polyether ester amide (). This will be explained in detail below using examples. Examples 1 to 3 Polyetheresteramides were obtained as follows. Polyetheresteramide A was prepared from 100 parts by weight of lauryl lactam, 26.3 parts by weight of α,ω-dihydroxy-(polytetrahydrofuran) with an average molecular weight of 860, and 7.0 parts by weight of dodecanedicarboxylic acid.
Polyether ester amide B was made from 100 parts by weight of laurin lactam, 78.9 parts by weight of α,ω-dihydroxy-(polytetrahydrofuran) with an average molecular weight of 860 and 21.1 parts by weight of dodecanedicarboxylic acid, and polyether ester amide C was made from 100 parts by weight of laurin lactam.
It was produced from 27.9 parts by weight of α,ω-dihydroxy-(polytetrahydrofuran) having an average molecular weight of 860 and 5.4 parts by weight of terephthalic acid. After mixing polylaurin lactam and polyether ester amide in the proportions shown in Table 1 using a twin-screw extruder, a film of approximately 100 μm was formed between approximately 50 μm of aluminum foil, and this was used as a sample for measuring the performance of a polymer thermosensor. And so. Using this sample, the temperature dependence of impedance was measured, and the thermistor B constant in the temperature range of 30°C to 60°C was determined, and is shown in Table 1.
It has a large temperature coefficient of impedance and is excellent as a polymer thermosensitive material. In addition, the blend of the present invention has excellent heat resistance and flexibility, so it is a polymeric thermosensitive material suitable for electric blankets, electric carpets, and the like. Comparative Example 1 Using polylaurin lactam, the performance was investigated in the same manner as in Example 1, and the results are shown in Table 1. 【table】

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an example of a heat-sensitive temperature control line, and FIG. 2 is a sectional view showing an example of a heat-sensitive temperature control surface. 1... Insulating material, 2... Core wire, 3... Polymer temperature sensitive body, 4... Signal line, 5... Heater wire.

Claims (1)

Claims: 1 at least one polyamide from ω-aminocarboxylic acids or lactams having a number of carbon atoms greater than 10; (a) ω-aminocarboxylic acids or lactams; (b) between 160 and 3000; α, ω- with molecular weight of
dihydroxy-polytetrahydrofuran; and (c) at least one polyetherester amide prepared from a dicarboxylic acid having from 4 to about 30 carbon atoms;
A polymer thermosensitive material comprising a mixture of 5 to 80 wt% of components and 95 to 20 wt% of components.