JPS6347124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polymeric thermosensitive material that has a novel polyesteramide resin as its main component and utilizes the temperature dependence of its impedance.

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 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-
(Refer to Publication No. 14179). Examples of applications of heat-sensitive temperature control lines or surfaces using these polymeric materials are shown in FIGS. 1A and 1B. A is a partially cutaway perspective view showing an example of a heat-sensitive temperature control line, which essentially consists of an insulating material, a core wire 2, a polymer temperature-sensitive body 3, a signal line 4, and a heater line 5. Further, B is a sectional view showing an example of a heat-sensitive temperature control surface. By adopting such a configuration, the electrical characteristics of the polymer temperature sensitive body 3,
That is, the temperature is detected and controlled along a thermosensitive temperature control line or surface by utilizing the fact that resistance value, impedance, or capacitance changes with temperature.

Among the polymer materials known as polymer thermosensors mentioned above, holamide resin has excellent electrical properties, mechanical properties, heat resistance, molding process, etc., so it can be used as a polymer thermosensor. Often used. 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 polymer thermosensitive body 3 shown in FIGS. 1A and B, the melting point of the polyamide resin is around 200°C, and the temperature of the heating wire may rise above the melting point due to abnormal temperature rise. When the temperature reaches
The polymer thermosensitive body melts, and the heating wire 5 and the signal wire 4 shown in FIGS. 1A and 1B are short-circuited, making it possible to activate the safety device.

Inorganic salts such as copper iodide, quaternary ammonium salts, etc. may be added to make the rate of change in resistance, impedance, or capacitance due to temperature even more remarkable in the temperature range in which it is used as a polymeric thermosensor. Usually done.

The disadvantage of polyamide resin, which is most commonly used as a thermosensor, is that its impedance is susceptible to fluctuations due to humidity due to its hygroscopic property, which inherently originates from the amide bonds in the polymer structure, and impedance is not a function of temperature alone. , the intended temperature regulation mechanism is affected by humidity. Therefore, among polyamide resins, nylon, which has a low amide bond concentration,
11 and nylon 12 are used, but their water absorption is still insufficient.

An object of the present invention is to provide a temperature sensitive body using a new and improved copolymerized polyesteramide in which the temperature dependence of impedance derived from water absorption, which is an inherent drawback of polyamide resins, is as small as possible.

As a result of extensive studies, the inventors found that a polyesteramide resin obtained by co-condensing hydrogenated polybutadiene with hydroxyl groups bonded to both ends with polyamide through ester bonds is suitable for the purpose of the present invention. Ta.

In the polyesteramide resin of the present invention,
Since the polyamide block and polybutadiene block are bonded by ester bonds, there is a shortage of carboxylic acid terminals that should be consumed by amide bonds, so in order to increase the molecular weight, it is necessary to add an acid concentration that is approximately equimolar to the hydroxyl group concentration. It is necessary to add a carboxylic acid, which is a basic acid. Thus, the composition of the polyesteramide resin of the present invention is as follows. That is, it has the structural units defined by A, B, and C below, and A
The constituent units of and the constituent units of B are bonded by amide bonds, the constituent units of A and the constituent units of C, and the constituent units of B and the constituent units of C are bonded by ester bonds, and the constituent units of C are 1 to 80 This is a novel copolymerized polyesteramide resin in which the molar ratio of the B structural unit to the C structural unit is 1:1.2 to 1:0.8 in terms of weight percent.

A Polyamide polymer component having one or more repeating units represented by general formula (1) or (2) -NH- (CH ₂ -) _o CO-, n is an integer from 5 to 12 (1) -NH-X- NH-COYCO- (2) (In the formula, X represents CmH ₂ m [m is an integer of 6 to 12], isophorone group, phenylene group, or cyclohexylene group, Y is ClH ₂ l [l is an integer of 4 to 10] ], represents a phenylene group or a cyclohexylene group.) B A structural unit represented by the following formula -OC-CmH ₂ m-CO-, m is an integer from 1 to 36 C A structural unit represented by the following formula -O-Z- O- In the formula, Z is a polybutadiene component hydrogenated to double bonds with an average molecular weight of 500 to 10,000,
It is bonded to oxygen at the end.

The polyamide polymer component can be formed by ring-opening polymerization of lactam, condensation polymerization of amino acids, condensation polymerization of diamine and dicarboxylic acid, or the like. The bifunctional carboxylic acid added to adjust the terminal group concentration of the polyesteramide resin and increase its molecular weight does not need to have a particularly limited structure, but when used as a co-condensation component with the polyamide polymer part, it does not follow the rules of polyamide. It is preferable that the polyamide has a number of methylene chains as close as possible to the number of methylene chains of the polyamide so as not to disturb the properties and reduce the crystallinity. For example, if nylon 12 is a polyamide component, α,ω dodecanedicarboxylic acid is most suitable. In order to obtain an infinite molecular weight of polyesteramide, it is theoretically necessary for the diol and dicarboxylic acid to be equimolar, but depending on the purpose, up to 20% above or below that ratio is allowed. Ru. The hydrogenated polybutadiene component can maintain desirable performance as a polyamide resin by forming blocks when it is made into a co-condensate. Therefore, if the number average molecular weight of the hydrogenated polybutadiene is 500 or less, the molecular chain of the polyamide part will inevitably become short, the polyamide part will not form its own crystalline phase, and the entire polyesteramide resin will become amorphous, which is preferable. do not have. In addition, when a hydrogenated polybutadiene component with a number average molecular weight of 10,000 or more is used, macro phase separation occurs, resulting in good molded products.
It is unsuitable because films etc. cannot be molded. Therefore, the preferred range of the molecular weight of the polybutadiene component is 500 to 10,000 in terms of number average molecular weight, and the most preferred range is
It is 1000-2000.

The molecular weight of the copolymerized polyesteramide resin of the present invention having such constituent components can be determined by adjusting the carboxylic acid terminal group concentration relative to the sum of the amino terminal group concentration and the terminal hydroxyl group concentration, and by adjusting the condensation reaction rate. Although the number average molecular weight can be adjusted to some extent depending on the number average molecular weight, the number average molecular weight is approximately 5,000 to 500,000.

In order to synthesize such a copolymerized polyesteramide resin according to the present invention, a condensation reaction between a difunctional carboxylic acid and an amino acid or a dicarboxylic acid and a diamine, or ring-opening polymerization of a lactam in the presence of a difunctional carboxylic acid is performed. A polyamide oligomer having a carboxylic acid group at the end is formed by this, and a block copolymer is formed by an ester-forming reaction between the terminal carboxylic acid group of this oligomer and a hydrogenated polybutadiene diol having a hydroxyl group at both ends. The hydrogenated polybutadiene diol may be added after the synthesis of the polyamide oligomer, or it may be allowed to coexist from the beginning of the polyamide synthesis so that the amide bond-forming reaction and the ester bond-forming reaction occur in parallel. be. In any case, since there is a difference in the equilibrium constants of the reversible reactions between the amide bond formation reaction and the ester bond formation reaction, the amide bond formation occurs first, and the block copolymer is completed by the ester bond formation reaction. A desorbed water removal process under high temperature and reduced pressure is essential. In addition, a polyester oligomer having a terminal carboxylic acid group is synthesized by first performing a condensation reaction between hydrogenated polybutadiene diol and a difunctional carboxylic acid, and then polycondensation of an amino acid or dicarboxylic acid and a diamine is performed in the presence of this oligomer. reaction or ring-opening polymerization of a lactam to produce a block copolymer through a condensation reaction accompanied by a transesterification reaction, or condensation accompanied by a transesterification reaction by reacting a polyester oligomer and a polyamide oligomer as described above. A method of forming a block copolymer by reaction is also possible.

The polyesteramide resin of the present invention has a low water absorption rate because the concentration of polar amide bonds and ester bonds is diluted by hydrocarbon chains by introducing hydrogenated polybutadiene chains, and the humidity dependence of impedance is small. . Furthermore, due to the clear melting point of the polyamide block portion, it melts in a narrow temperature range, so it has properties as a thermal fuse. Therefore, it is suitable as a material for a temperature sensitive body with low humidity dependence, which is the object of the present invention.

The polyesteramide of the present invention can be molded into a linear or planar shape and used as the above-mentioned temperature sensitive body.
At this time, in order to increase the rate of change in impedance due to temperature, it is also possible to add additives such as metal salts such as copper iodide or quaternary ammonium salts, as is generally done with polymer thermosensors. It is.

EXAMPLES The present invention will be explained below using Examples, but the present invention is not limited thereto, of course.

Example 1 39.6 g of ω-aminododecanoic acid and 4.54 g of α,ω-dodecanedicarboxylic acid were subjected to a condensation reaction at 190°C for 4 hours under a nitrogen stream in a separable flask equipped with a stirrer, and the end of _O 1490 was added to the reaction mixture. 29.4 g of hydrogenated polybutadiene having hydroxyl groups and 0.05 g of dibutyltin oxide were added to the mixture, and the mixture was further reacted at 190° C. for 7 hours under a nitrogen stream. 14 g of the obtained low degree of condensation reactant was transferred to a stainless steel micro cylinder and reacted under a reduced pressure of 1 mmHg at 210°C for 1 hour, 230°C for 2 hours, and 270°C for 8 hours. The obtained polymer had a number average molecular weight of 9100 according to end group analysis, and could be molded into a strong sheet. After the sheet was kept in water at 40°C for one week, the moisture content was 0.502% by weight. The impedance of this sheet was measured in a dry state after 5 days of vacuum drying at 70°C and after 1 week of being kept in water at 40°C. The impedance was 3.0×10 ⁹ Ω at 100Hz and 50°C, respectively.
cm and 2.4×10 ⁹ Ωcm, with a difference of only 0.6
It was ×10 ⁹ Ωcm. DSC at heating rate 10℃/min
When measured, it showed clear melting behavior of a crystalline polymer with a melting range of 153 to 176°C, a peak temperature of 170°C, and a heat of fusion of 7.1 cal/g. This copolymerized polyesteramide resin can be suitably used as a heat-sensitive element for electric blankets and electric carpets because its impedance is not easily affected by humidity and its distinct melting point allows it to be used as a thermal fuse.

Comparative example 1 40 sheets of nylon 12 with a number average molecular weight of 24,000
Moisture content after one week in water at ℃ is 1.6% by weight
It was hot. The impedance of this sheet is 70℃5
Measurements were made after vacuum drying for 1 day and after being held in water at 40°C for 1 week. At 100 Hz and 50°C, the resistance was 3.0 x 10 ⁹ Ωcm and 1.1 x 10 ⁹ Ωcm, and the difference between them was 1.9 x 10 ⁹ Ωcm. DSC was also measured for this sheet.
The melting range was 164-184°C, the peak temperature was 179°C, and the heat of fusion was 9.2 cal/g.

[Brief explanation of the drawing]

FIG. 1A is a partially cutaway perspective view showing an example of a heat-sensitive temperature control line, and FIG. 1B 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)

[Scope of Claims] 1 It has the constituent units defined by A, B, and C below, the constituent units of A and the constituent units of B are bonded through an amide bond, and the constituent units of A, the constituent units of C, and the constituent units of B The constituent units of and the constituent units of C are bonded by an ester bond, the constituent units of C account for 1 to 80% by weight, and the molar ratio of the constituent units of B and the constituent units of C is 1:
A polymer thermosensitive material whose main component is a new copolymerized polyesteramide resin with a ratio of 1.2 to 1:0.8. A Polyamide polymer component having one or more repeating units represented by general formula (1) or (2) -NH- (CH ₂ -) _o CO-, n is an integer from 5 to 11 (1) -NHXNHCOYCO- (2 ) [In the formula, X is CmH ₂ m (m is an integer from 6 to 12),
It represents an isophorone group, a phenylene group or a cyclohexylene group, and Y represents ClH ₂ l (l is an integer from 4 to 10), a phenylene group or a cyclohexylene group. ] B Structural unit represented by the following formula -OC-CmH ₂ m-CO-, (m is an integer from 1 to 36) C Structural unit represented by the following formula -O-Z-O- (Z is an average molecular weight of 500 to A polybutadiene component hydrogenated to 10,000 double bonds, bonded to oxygen at the end).