JPS6228562B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention improves the resistance value, impedance, or capacitance behavior of a heat-sensitive material with respect to temperature in a device that controls temperature using a polymeric temperature sensitive body made of a specific polyamide resin composition, particularly 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 properties depending on the usage environment of the heating element, especially temperature; (3) mechanical strength and electrical properties within the normal operating temperature range. (4) It has a clear melting point at around 200℃ in order 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.
That is, when a polyamide resin is used for the polymeric temperature sensitive body shown in FIG. 1, the melting point of the polyamide resin is around 200°C, and if the temperature of the heating wire exceeds the melting point due to abnormal temperature rise, The polymer temperature sensitive body melts, causing a short circuit between the heating wire 5 and the signal wire 4 shown in FIGS. 1A and 1C, 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. Due to these drawbacks, it has not yet reached a level where it can be put to practical use. 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, it is not possible to increase the temperature change in the electrical properties of polyamide resin by adding surfactants such as stearyldimethylbenzylammonium chloride described in Japanese Patent Publication No. 35-14179. However, its heat resistance is too poor to be kneaded into polyamide resin, so it is almost impossible to knead it into polyamide resin. In addition, nylon 6, which is a typical polyamide resin, as described in Japanese Patent Publication No. 1627/1983,
Alternatively, in the case of nylon 66, etc., its water absorption ability is too high for a heat-sensitive material, so for example,
As is already known for heat-sensitive wires for electric blankets, even if a moisture-proofing film such as polyvinyl chloride is formed on the outermost layer, it is difficult to obtain substantially complete moisture-proofing. For this reason, nylon 6 or nylon
The control temperature point of a heat sensitive body using 66 or the like fluctuates significantly 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. Therefore, the present inventors conducted a comprehensive study on various polyamide resins, and as a result, polyamide resins having 14 or less amide groups per 100 carbon atoms, such as nylon 11, nylon 12, and nylon 6/12, were developed. These polyamide resins have low water absorption and have excellent other physical properties, so if they are used as polymeric materials for polymeric thermosensors,
It has been found that there is no fluctuation in electrical properties unlike the above-mentioned nylon 6 or nylon 66, and that an excellent heat-sensitive material can be provided. Furthermore, as a result of investigating various additives to improve the electrical properties of polyamide resins such as nylon 12 having 14 or less amide groups per 100 carbon atoms, the following general formula () was found. Compound [However, in the formula, R ₁ represents an aliphatic group, an alicyclic group, or an aromatic hydrocarbon group having 1 to 10 carbon atoms, and these may have a substituent. R ₂ , R ₃ and R ₄ may be the same or different, but

【formula】

【formula】

【formula】

Indicates a group selected from [Formula] (where R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ are aliphatic groups with 1 to 30 carbon atoms, alicyclic groups, aromatic carbonized groups) represents a hydrogen group, which may have a substituent). ] was found to significantly improve the electrical properties. In other words, it has been found that polyamide resins to which such additives have been added greatly increase the rate of change in resistance, impedance, or capacitance due to temperature, and exhibit properties that are truly desirable as polymer thermosensitive materials for electric blankets, etc. . In addition, the electrical property improver used in the present invention has excellent heat resistance and can be practically kneaded into polyamide resin, and when used in electric blankets, electric carpets, etc., the electrodes thereof have excellent corrosion resistance. I found out. Furthermore, since this additive is also an adhesion improving agent, it is more effective in bonding aluminum foil to a polymer temperature sensitive body such as an electric carpet. That is, the present invention applies the compound represented by the general formula () to a low water absorption polyamide resin made of a polyamide resin having 14 or less amide groups per 100 carbon atoms, such as nylon 11 or nylon 12, by adding 100% by weight of the resin. It has been discovered that the composition material can be an excellent polymeric thermosensitive material by blending 0.01 to 10 parts by weight per part of the composition. The polyamide resin having 14 or less amide groups per 100 carbon atoms used in the present invention includes:
A low water absorption polyamide resin made of a nylon copolymer whose main component is a polyamide resin component as described above may also be used. Examples of the compound represented by the general formula () include: isopropyl triisostearoyl titanate (Example 1) isopropyl tri(dodecylbenzenesulfonyl) titanate Isopropyl tri(diisooctyl phosphate) titanate Isopropyl di(dodecylbenzenesulfonyl) 4-aminobenzenesulfonyl titanate (Example 2), isopropyl isostearoyl di-
4-aminobenzoyl titanate (Example 4),
Examples include isopropyl tri(dioctylpyrophosphate) titanate (Example 5). Further, the amount of the compound represented by the general formula () in the present invention varies depending on the polyamide resin or the type of the compound, but it is generally added in an amount of 0.01 to 10 wt% relative to the polyamide resin.
If it is less than 0.01wt%, it will not show electrical properties that can be put to practical use, and if it is more than 10wt%, there is a risk that the mechanical properties of the polyamide resin will deteriorate, and the additives may bleed over time, causing changes in electrical properties over time. This is because it may indicate a change. Furthermore, it is also possible to coexist the above-mentioned compounds of the present invention with other ionic compounds, such as potassium iodide and copper iodide, to further improve the electrical properties due to the synergistic effect of the additives. When adding and mixing the compound represented by the general formula () to the polyamide resin, there is no particular limitation on the method of addition, as long as the compound can be uniformly dispersed in the polyamide resin, and it can be carried out using a general extruder. Melt extrusion mixing is possible. During melt extrusion, other additives such as plasticizers, light stabilizers, heat stabilizers, fillers, flame retardants, colorants, etc. may be used in combination within the range that does not affect the electrical properties of the composition. However, the purpose of the present invention is not hindered in any way. The effects of the present invention will be explained below using examples. Example 1 2.0wt% of a compound having the following structure was added to nylon 12 pellets (Diamide L-1901, registered trademark of Daicel Corporation). The mixtures were thoroughly mixed in advance using a Henschel mixer and then melt-blended using an extruder (polymer temperature approximately 200°C) to obtain blended pellets with a good appearance. Next, this pellet was compression molded (polymer temperature about 200℃) to form a sheet of about 0.2mm thick between aluminum foils of about 50μ thickness and used as a form of temperature sensor.The dielectric properties at 1KHz were measured at 20℃~
Measurements were made in a temperature range of 120°C, and the results shown in Figure 2A were obtained. For comparison, the dielectric properties of the original nylon 12 polymer were measured under similar conditions, and the results shown in Figure 2B were obtained. From these results, it is clear that the rate of change in dielectric constant with temperature is improved compared to the original nylon 12 polymer. Furthermore, the impedance characteristics were measured at an electric field strength of 1 KV/cm (50 Hz), and the results are shown in Figure 3. However, symbols A and B are the same as in the case of FIG. From this result, it is clear that the rate of change in impedance with temperature is improved compared to the original nylon 12 polymer. Example 2 The dielectric properties and impedance properties of nylon 12 mixed with 2.0wt% of a compound having the following structure were measured in the same manner as in Example 1.
The results are shown as C in FIGS. 2 and 3.
From this result, it is clear that the temperature change rate of dielectric constant and impedance is improved compared to the original polyamide resin. Example 3 The dielectric properties and impedance properties of nylon 12 mixed with 0.5wt% of the compound having the structure of Example 2 were measured in the same manner as in Example 1, and the results are shown in Figures 2 and 3. It is shown as D. From this result, it is clear that the temperature change rate of dielectric constant and impedance is improved compared to the original polyamide resin. Example 4 The dielectric properties and impedance properties of nylon 12 mixed with 2.0wt% of a compound having the following structure were measured in the same manner as in Example 1.
The results are shown as E in FIGS. 2 and 3. From this result, it is clear that the temperature change rate of dielectric constant and impedance is improved compared to the original polyamide resin. Example 5 The dielectric properties and impedance properties of nylon 12 mixed with 2.0wt% of a compound having the following structure were measured in the same manner as in Example 1.
Similar results as in Example 1 were obtained. From this result, it is clear that the temperature change rate of dielectric constant and impedance is improved compared to the original polyamide resin.

[Brief explanation of the drawing]

FIGS. 1A to 1C are side or cross-sectional views showing examples of heat-sensitive temperature control lines or surfaces used in electric blankets, electric carpets, and the like. FIGS. 2 and 3 are graphs showing changes in dielectric constant and volume specific impedance with respect to temperature, respectively, when a compound represented by the general formula () is added to nylon 12.

Claims (1)

[Scope of Claims] 1. A polyamide resin containing 0.01 to 10% by weight of at least one compound represented by the following general formula [] to a polyamide resin having 14 or less amide groups per 100 carbon atoms. A polymer thermosensitive body consisting of a composition. [However, in the formula, R ₁ is an isopropyl group, R ₂ , R ₃ , R ₄
may be the same or different, but is a group selected from isostearoyl, dodecylbenzenesulfonyl, diisooctylphosphate, 4-aminobenzenesulfonyl, 4-aminobenzoyl and dioctylpyrophosphate. shows. ]