JPS6347121B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention improves the behavior of resistance value, impedance, or capacitance with respect to temperature and moisture absorption of a polymer thermosensitive material made of polyether esteramide, especially a heat-sensitive material in a device that controls temperature using a capacitance component as a control factor. The present invention relates to a polymer thermosensitive body. 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 characteristics depending on the environment in which the heating element is used, especially humidity; and (3) a clear melting point to cope with abnormal temperature rises. (4) Mechanical strength and electrical properties do not deteriorate within the normal temperature range. 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). Among the above-mentioned polymeric thermosensitive materials, polyamide resins are often used as polymeric thermosensitive materials because they are excellent in various aspects such as electrical properties, mechanical properties, heat resistance, and moldability. Furthermore, polyamide resin is a crystalline polymer and has a clearer melting point than other resins, making it possible to cope with abnormal temperature rises. When polyamide resin is used for the polymer thermosensitive material, the melting point of polyamide resin is 200℃.
When the temperature of the heating wire reaches or exceeds its melting point due to abnormal temperature rise, the polymer temperature sensitive body melts, making it possible to operate the heating wire, signal wire, and safety device. 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 the following drawback. 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. That is, it is possible to add surfactants such as stearyldimethylbenzylammonium chloride described in Japanese Patent Publication No. 35-14179 to polyamide resin to increase the temperature change in its electrical properties. but,
Since the heat resistance is too poor to be kneaded into polyamide resin, it is almost impossible to knead it into polyamide resin. 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. . 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 6/12, and nylon 12/12 to which electrical property improvers are added 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, although it is said to be superior to nylon 6 and nylon 66 in terms of fluctuations in the control temperature point due to moisture absorption, depending on the operating atmosphere, the operating temperature may deviate by 20 to 30 degrees Celsius, and many practical problems remain. It's on. As a result of intensive studies in view of the above-mentioned problems, the inventors of the present invention have found that a composition in which one or more compounds selected from copper salts and potassium halides are added to polyether ester amide is superior. It was discovered that it can be used as a polymer thermosensitive material, and the present invention was achieved. The polyether ester amide, which is the main component of the polymer thermosensitive material of the present invention, is a polyamide whose main component is a polyamide obtained from an ω-aminocarboxylic acid or lactam in which at least one component of the polyamide segment has 10 or more carbon atoms. It is an ether ester amide. In other words, it is a thermoplastic elastomer obtained by pressurizing and heating a compound having polyamide-forming properties consisting of ω-aminocarboxylic acid or lactam having 10 or more carbon atoms and α,ω-dihydroxypolyether in the presence of an organic dicarboxylic acid. , is a polyether ester amide in which polyamide as a hard segment part and polyether as a soft segment part are connected by an ester bond using a dicarboxylic acid. Such a polyether ester amide is disclosed, for example, in JP-A-53-119997, and the polyamide-forming component is, for example, ω-aminoundecanoic acid, especially lauryl lactam, and the diol component is a compound with a molecular weight of 160 to 160. 3000, especially 500~
α,ω-dioxy (polytetrahydrofuran) having a carbon number of 1200, particularly as a dicarboxylic acid with a carbon number of 4
Dicarboxylic acids having a molecular weight of ˜30 are preferably used, preferably dikanedicarboxylic acid, hexahydroterephthalic acid, terephthalic acid and/or isophthalic acid, respectively. A polyamide may be added to this polyetheresteramide. Examples of the polyamide added in this case include nylon-11, nylon-12, and nylon 612. As the copper salt in the present invention, organic acid copper such as copper acetate or copper benzoate, or copper halide such as copper iodide or copper bromide is used. Further, complex salts of copper halides, such as complex salts of copper iodide and 2-mercaptobenzimidazole, etc. can be mentioned. Further, examples of the potassium halide include potassium iodide. Particularly preferred are copper iodide, potassium iodide, or a combination thereof. The amount of these additives is 200 to 5000 ppm as copper or potassium.
Preferably it is 500 to 3000 ppm. As the method for adding the copper salt or halide, commonly used methods can be considered, such as adding it in the polymerization step of the polyether ester amide and mechanically mixing it with the polyether ester amide chips. A suitable method is to mix it with an ester amide and then melt-knead it in an extruder. At this time, it is also possible to add heat-resistant stabilizers, lubricants, etc. at the same time. The features of the polymer temperature sensitive body of the present invention are as follows:
First, the fluctuation of the control temperature point due to moisture absorption is much smaller than that of conventionally known polymer temperature sensitive bodies. Second, the temperature detection sensitivity expressed by the thermistor B constant is improved, and highly accurate temperature control becomes possible. Thirdly, since it has a clear melting point and extremely sharp melting behavior, it has the advantage of being able to function as a highly accurate temperature fuse when used in electronic blankets, electronic carpets, etc. The present invention will be explained below with reference to Examples and Comparative Examples. Example 1 Laurinlactam 100 parts by weight, average molecular weight 1000
Polyether ester amide synthesized from 27.0 parts by weight of α,ω-dihydroxy-(polytetrahydrofuran) and 7.0 parts by weight of decanedicarboxylic acid.
100 parts by weight of copper iodide (CuI) as copper
2000 ppm was added, mixed using a Henschel mixer, and then melt blended using an extruder to obtain chips with a good appearance. This pellet was molded into a sheet approximately 1 mm thick using a compression molding machine. this sheet
After vacuum drying at 60°C for 24 hours, the volume specific impedance at 60Hz was measured. Further, after leaving a similar sheet in water at 40°C for 5 days, the specific volume impedance was measured.
The results are shown in Table-1. Example 2 Copper iodide was added to 100 parts by weight of polyether ester amide obtained in the same manner as in Example 1.
The same test as in Example 1 was conducted by adding 500 ppm and kneading. The results are shown in Table 1. Example 3 Laurinlactam 100 parts by weight, average molecular weight 1000
To 100 parts by weight of polyether ester amide synthesized from 80 parts by weight of α,ω-dihydroxy (polytetrahydrofuran) and 20 parts by weight of decanedicarboxylic acid, 2000 ppm of copper iodide was added and kneaded, and the mixture was mixed in the same manner as in Example 1. The test was conducted. The results are shown in Table 1. Example 4 750 ppm of potassium iodide as potassium was added to 100 parts by weight of polyether ester amide obtained in the same manner as in Example 3 and kneaded, and the same test as in Example 1 was conducted. The results are shown in Table 1. Comparative Example 1 A sheet was prepared in which no copper iodide was added in Example 1, and the same test was conducted. The results are shown in Table 1. Comparative Example 2 A test was conducted in the same manner as in Example 1 using nylon 12 (manufactured by Daicel Hüls, trade name "Diamid" L1901). The results are shown in Table 1.

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Claims (1)

[Claims] 1 At least one of the components constituting the polyamide block is a polyether ester amide mainly composed of a polyamide obtained from an ω-aminocarboxylic acid or lactam having 10 or more carbon atoms, and a polyether ester amide selected from copper salts and potassium halides. A polymer thermosensitive material containing 200 to 5000 ppm of copper and/or potassium containing one or more kinds of compounds.