JPH0945507A - Polymer thermosensitive body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer thermosensitive body which has a good thermistor characteristic, which is excellent in the long-term stability of an electric characteristic, whose sensitivity is high and whose reliability is high. SOLUTION: A polymer thermosensitive body is composed of a polyamide resin composition in which a polyamide resin is mixed with a conductivity- imparting agent in which one or more kinds of salts selected from a metal thiocyanate, a metal halide and a perchlorate is dissolved in polyalkylene oxide containing an amino group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymeric temperature sensor used for temperature detection for controlling the temperature of sheet heating elements such as electric blankets and electric carpets.

[0002]

2. Description of the Related Art It has been well known that polymer materials can be used as a temperature-sensitive element for surface heating appliances such as electric carpets by taking advantage of the temperature dependence of electrical characteristics. The temperature control circuit is operated by utilizing the characteristics such as the dielectric constant, the DC resistance, and the impedance of the temperature sensitive material that change with temperature.

The properties required of such a polymer temperature-sensitive material are (1) a large change in the electric properties of the polymer with temperature, (2) a small change in the electric properties with time, and (3) ) Less moisture absorption, or less change in electrical properties due to moisture absorption, and (4) excellent mechanical properties such as bending resistance.

Polyamide resin is suitable as a heat-sensitive material because it has a large temperature dependency of the above-mentioned electrical characteristics, and also has excellent mechanical characteristics and moldability, and nylon 11 and nylon 12 having particularly low water absorption. The composition of is preferably used.

In addition, JP-A-48-6648 and JP-A-4
No. 8-99691, JP-A-61-2303, etc., these nylons are blended with a phenolic compound,
Alternatively, JP-A-52-27594 and JP-A-58-21
5449, JP-A-60-106101, etc., the temperature dependence of electric characteristics is improved by a method of blending a metal salt.

By the method of improving the electric characteristics as described above,
Although the effect of improving the electrical properties of nylon is recognized, there are changes over time in the electrical properties due to decomposition and volatilization of the phenolic compound added during long-term use, and variations in sensitivity due to poor compatibility of the added salts with nylon. When used as a warm body, there was a drawback that the electrical characteristics changed due to the polarization phenomenon due to the DC component of the applied current. Therefore, no material has hitherto been obtained which satisfies all the properties required for the polymer temperature sensitive material, such as the initial thermistor property of the temperature sensitive body and the long-term property stability when DC or AC is applied.

Further, Japanese Patent Laid-Open Nos. 6-5175 and 6-
No. 124805 describes a polymer temperature-sensitive material characterized in that a conductivity-imparting agent obtained by dissolving lithium perchlorate in polyethylene oxide as a conductivity-imparting agent is blended with a polyamide resin. However, the low-molecular-weight polyethylene oxide used here has low water resistance and easily absorbs water under high humidity, and easily bleeds on the surface of the polyamide. Therefore, such a polymer temperature-sensitive material obtained by blending such a lithium perchlorate or a polyethylene oxide-based conductivity-imparting agent into a polyamide resin is liable to cause a change in electrical characteristics with time when used for a long time as a heating appliance. was there.

[0008]

In view of the above points, the present invention has excellent initial thermistor properties, is free from bleeding of the conductivity-imparting agent, and is excellent in long-term stability of electrical properties.
It is an object of the present invention to provide a polymeric thermosensitive body having a favorable sensitivity and high reliability.

[0009]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve these problems, and as a result, by using a polyalkylene oxide having an amino group as a base of a conductivity-imparting agent, Since it is incorporated into the resin by interaction with the carboxyl group in the polyamide, it is possible to suppress bleeding of the conductivity-imparting agent from the polyamide resin, and by increasing the polarity of the base by the amino group, the conductivity-imparting agent It has been found that the solubility of ionic salts in water is significantly improved.

By using the salt-dissolved product of the amino group-containing polyalkylene oxide as a conductivity-imparting agent for the polymer thermosensitizer, the initial polymer thermistor properties are excellent and the long-term stability of the electrical properties is excellent. They found that a warm body was obtained, and completed the present invention.

That is, the present invention is a thiocyanic acid metal salt,
A polymer having a polyamide resin composition in which a conductivity-imparting agent prepared by dissolving one or more salts selected from metal halide salts and perchlorates in amino group-containing polyalkylene oxides is blended with a polyamide resin. It is a warm body.

The polyamide resin that can be used in the polymer thermosensitive material of the present invention is not particularly limited, but from the viewpoint of water absorption and electrical characteristics, a polyamide having an amide group concentration of 14 or less per 100 carbon atoms. Resin can be preferably used.
Examples of such polyamide resins include polyundecane amide (nylon 11) and polydodecane amide (nylon 1).
2), N-alkyl substituted polyamides, polyether amides, polyether ester amides, dimer acids and / or
Alternatively, polyamides such as hydrogenated dimer acid-containing polyamides and copolymers thereof can be used.

The metal thiocyanate used in the present invention includes lithium thiocyanate, sodium thiocyanate,
Examples thereof include potassium thiocyanate, rubidium thiocyanate, cesium thiocyanate, magnesium thiocyanate, calcium thiocyanate, zinc thiocyanate and copper thiocyanate.

Examples of the metal halide used in the present invention include lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide, magnesium iodide, calcium iodide, zinc iodide, and iodine. Metal iodide salts such as copper oxide, lithium chloride, sodium chloride,
Potassium chloride, rubidium chloride, cesium chloride, magnesium chloride, calcium chloride, zinc chloride, copper chloride and other metal chloride salts, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, magnesium bromide, Mention may be made of metal bromide salts such as calcium bromide, zinc bromide and copper bromide.

The metal salt of perchloric acid used in the present invention includes
Lithium perchlorate, sodium perchlorate, potassium perchlorate, rubidium perchlorate, cesium perchlorate, magnesium perchlorate, calcium perchlorate, zinc perchlorate,
Copper perchlorate etc. can be mentioned.

The amino group-containing polyalkylene oxide used in the conductivity-imparting agent of the present invention includes a monoamine or an amino group-containing polyalkylene oxide (a) having a polyalkylene oxide unit bonded to the nitrogen atom of the polyamine, a monoamine, or First class of polyamine,
An amine compound or amino group-containing polymer (b) obtained by adding an epoxy compound having a polyalkylene oxide unit to a secondary nitrogen atom, a methacrylic acid ester having a polyalkylene oxide unit at a primary or secondary nitrogen atom of a monoamine or polyamine. An amine compound or an amino group-containing polymer (c), a polyalkylene glycol, or a terminal carboxyl group polyalkylene oxide or a terminal amino group polyalkylene oxide, and a dicarboxylic acid,
Examples thereof include oligomers or polymers (d) produced by condensation reaction with polyols and diamines.

As the amino group-containing polyalkylene polyether having an ether bond corresponding to the structure (a),
PEO-amines marketed by Kawaken Fine Chemicals Co., Ltd., Ionette YB- marketed by Sanyo Kasei
400, Pionine D-3104 (polyoxyethylene lauryl amino ether) manufactured by Takemoto Yushi, and the like.

The amino group-containing polyalkylene oxide corresponding to the structure (b) is a polyalkylene glycol having a glycidyl group or an epoxy group at the terminal (eg, Epiol P-400 manufactured by NOF Corporation, Glycier PP manufactured by Sanyo Kasei).
-300P, PP-700P, PE-300P, BPP
-350 etc.) and an amine having a primary or secondary amino group,
For example, hexamethylenediamine, ethylenediamine,
It can be easily produced by reacting with N, N-dimethylaminopropanediamine, tetraethylenepentamine, polyethyleneimine and the like.

The amino group-containing polyalkylene oxide corresponding to the structure (c) is a methacrylate containing a polyalkylene polyether unit, for example, Blemmer AE-350, AP-40 commercially available from NOF Corporation.
0 (monometallate), ADE-400 (dimethacrylate) and the like are amines having a primary or secondary amino group, for example, diamines such as hexamethylenediamine, ethylenediamine, N, N-dimethylaminopropanediamine, and tetraethylenepenta. It can be easily obtained by adding Michael to amine or polyethyleneimine.

The amino group-containing polyalkylene oxide corresponding to the structure (d) can be easily produced by dehydration condensation of polyalkylene glycols, dicarboxylic acid, polyol and diamine. In this case, the amount of diamine needs to be excessive in order to have a structure having an amino group (diamine unit) at the terminal.
As a raw material, as a polyalkylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, a polyalkylene glycol derivative such as an ethylene oxide or propylene oxide adduct of bisphenol A (for example, Newyole BPE and BP series manufactured by Sanyo Kasei Co., Ltd.) , Polyoxyethylene nonylphenyl ether, ethylene oxide
A nonionic surfactant having a terminal hydroxyl group such as a propylene oxide block copolymer can be used.

These amino group-containing polyalkylene glycols having an average molecular weight of 100 to 50,000, particularly preferably 200 to 20,000, have low crystallinity, good workability during production, and high migration of the conductive carrier. It is preferable from the viewpoint of obtaining the degree.

As the constituent unit of the polyalkylene oxide group, a polyethylene polyether having 2 carbon atoms, a polypropylene polyether having 3 carbon atoms as a constituent unit,
Polytetramethylene polyether having a carbon number of 4 as a constituent unit and a copolymer thereof are industrially available and have excellent characteristics. The alkylene oxide unit may have a side chain having 1 to 5 carbon atoms.

Metal thiocyanate, metal halide,
The conductivity-imparting agent obtained by dissolving a perchloric acid metal salt or the like in an amino group-containing polyalkylene oxide is prepared by first heating the amino group-containing polyalkylene oxide to 50 to 150 ° C., and in the case of solid amino group-containing polyalkylene oxide, In the case of a liquid amino group-containing alkylene oxide that is melted and reduced in viscosity, the metal salt is gradually added with stirring to dissolve it, or the metal salt and the amino salt are dissolved in a solvent such as water or a lower alcohol. It can be produced by dissolving the group-containing polyalkylene oxide, thoroughly stirring and distilling off the solvent. Moreover, you may use it in the state melt | dissolved in the solvent as needed.

The concentration of the metal salt contained in the conductivity-imparting agent is in the range of 1 to 50% by weight, preferably 5 to 40% by weight. At a metal salt concentration of 1% by weight or less, since the content of metal ions involved in conductivity is low, a large amount of a conductivity-imparting agent must be blended in the polyamide resin, resulting in excellent processability and resistance to resistance of the polyamide resin. The chemical resistance and weather resistance will be impaired. Further, at a metal salt concentration of 50% by weight or more, the viscosity of the conductivity-imparting agent is extremely high, and the metal salt easily precipitates, which makes it difficult to handle, and the conductivity-imparting agent containing such a high-concentration metal salt is The preparation requires high temperature and long stirring time, and is difficult to manufacture.

The content of the conductivity-imparting agent in which a metal salt such as a metal salt of thiocyanate is dissolved in an amino group-containing polyalkylene oxide to be kneaded with a polyamide resin is preferably 0.01% by weight to 20% by weight. If the amount is less than 0.01% by weight, the performance as an ionic conductor is extremely low. On the other hand, if the amount is more than 20% by weight, strands are likely to break during melt-kneading and extrusion with a polyamide resin, which makes production difficult. Further, the blended polyamide resin is inferior in mechanical properties, and the thermistor properties are also poor because there are too many conductive components. In addition, the polarization effect when a direct current is continuously applied becomes strong, and it is not suitable as a polymer temperature sensitive material.
A more preferable compounding amount of the conductivity-imparting agent is 0.1 to 10% by weight.

Various additives can be added to the polyamide resin composition of the present invention for the purpose of further improving the electrical characteristics. As such additives, known phenolic compounds and phenolic resins, further lowering water absorption,
From the viewpoint of preventing a change in electrical characteristics over time, a phenol resin oligomer or polymer having an alicyclic skeleton is preferable, and DPP series, PP series manufactured by Nippon Oil Co., Ltd. can be preferably used.

Needless to say, various polymer additives such as antioxidants and heat stabilizers may be used in combination with the polyamide resin composition of the present invention for the purpose of improving heat resistance, weather resistance and the like.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the polymer temperature sensor of the present invention will be described below with reference to Examples, but the present invention is not limited thereto.

[0029]

EXAMPLES Synthesis of amino group-containing polyalkylene oxide Synthetic base NO. (1) In a 2 L reactor connected with a stirrer, a cooling pipe, and a nitrogen introduction pipe, 550 g of Glycyere PP300P (polyoxypropylene glyceryl ether; n = 7; Sanyo Kasei Co., Ltd.) was placed and heated to 60 ° C. Then
204 g of N, N-dimethylpropanphenamine was added dropwise and reacted until the oxirane oxygen concentration became 0.1% or less. The product was a viscous liquid with an amine value of 149 mg KOH / g.

Synthetic base NO. 2 Araldite GL62 (bisphenol A diglyceride ether; manufactured by Ciba Geigy) 35 was placed in a 2 L reactor connected with a stirrer, a cooling pipe, and a nitrogen introducing pipe.
g and Ionet YB-400 (terminal amino group polyethylene oxide; manufactured by Sanyo Kasei)
The mixture was heated to 20 ° C. and reacted until the oxirane oxygen concentration became 0.1% or less. The product has an amine value of 24 mg KOH
/ G and was solid at room temperature.

Synthetic base NO. 3 200 g of 1,12-dodecamethylenediamine, and 750 g of Bremmer AE-350 (polyethyleneoxy monoacrylate; n = 7; NOF Corporation) were placed in a 2 L reactor connected with a stirrer, a cooling pipe, and an air introduction pipe. 0.7 g was taken, the temperature was slowly raised to 100 ° C., and the reaction was continued until the double bond disappeared. The product had an amine value of 115 mgKOH / g and was a viscous liquid.

Synthetic base NO. 4 In a 2 L reactor connected with a stirrer, a cooling pipe, and an air introduction pipe, 748 g of Bremmer ADE-400 (polyethyleneoxy diacrylate; n = 9; made by NOF Corporation), 0.5 g of methylhydroquinone, 1,12-dodecamethylene Take 43 g of diamine and slowly raise the temperature to 60 ° C.
Then, 209 g of n-butylamine was added dropwise and reacted until the double bond disappeared. The product has an amine value of 161 mgK
It was a viscous liquid at OH / g.

Synthetic base NO. 5 Newpol BPE180 (bisphenol A ethylene oxide adduct (18 mol); Sanyo Kasei Co., Ltd.) 737.5 g, dodecanedioic acid 227.8 g, in a 2 L reactor connected with a stirrer, a cooling pipe, a dehydration pipe, and a nitrogen introduction pipe. After adding 0.5 g of monobutyltin oxide and heating and stirring at 150 ° C. for 3 hours, the temperature was raised to 200 ° C. over 4 hours, and the reaction was continued until the acid value reached 43 mgKOH / g. Then N, N-dimethylpropanediamine 73.8
g and 1 g of phosphoric acid were added, the temperature was raised to 250 ° C., and the reaction was continued until the amine value reached 41 mgKOH / g. The product was a highly viscous resin at room temperature.

Preparation of conductivity- imparting agent A metal salt which imparts conductivity is heated and mixed with the base amino group-containing polyalkylene oxide at a mixing ratio (parts by weight) shown in Table 1, and then homogenized until completely transparent. The mixture was stirred with a mixer (about 3000 rpm) to prepare a conductivity imparting agent.

In the same manner, the conductivity-imparting agent NO. 1-NO. 7 was prepared.

[0036]

[Table 1] Examples 1 to 7 and Comparative Example Nylon 12, nylon 12 elastomer and hydrogenated dimer acid-modified nylon 12 manufactured by Daicel Huls Co., Ltd. were used as the polyamide resin, and the conductivity imparting agent NO. 1 to
NO. 7 and the additives were blended in a ratio (parts by weight) shown in Table 2, melt-kneaded at 220 ° C. by an extruder, and pelletized by a pelletizer.

These pellets at 210 ° C. with a thickness of about 0.
A film of 5 mm was formed, then dried at 100 ° C. for 2 hours, a tin electrode was attached, and the impedance at each temperature at 100 Hz was measured by Yokogawa-Hewlett Packard L
The evaluation results were shown in FIGS. 1 and 2 as measured by a CR meter.

As a comparative example, the impedance of nylon 12 alone at each temperature was measured.

[Table 2]

[0039]

EFFECT OF THE INVENTION By adding a small amount of the conductivity-imparting agent of the present invention to a polyamide composition, good thermistor characteristics, which cannot be obtained by conventional metal salts alone, can be obtained, and the conductivity-imparting agent bleeding and the like can be obtained. In addition, it is possible to prevent a long-term change in the electrical characteristics under high temperature over time, and to obtain a highly sensitive and highly reliable polymer temperature sensor. Further, the polyamide resin composition of the present invention has an appropriate melting point and also has a function as a thermal fuse, and satisfies the mechanical properties required for a heat sensitive wire.

[Brief description of drawings]

FIG. 1 is a graph showing the measurement results of impedance at each temperature of the polymer temperature sensor and nylon 12 of Examples 1 to 4 of the present invention.

FIG. 2 is a graph showing the measurement results of the impedances of the polymer temperature sensor and nylon 12 of Examples 5 to 7 of the present invention at various temperatures.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08L 71/02 LQE C08L 71/02 LQE 77/00 LQV 77/00 LQV

Claims (1)

[Claims] 1. A polyamide resin is blended with a conductivity-imparting agent in which one or more salts selected from metal thiocyanates, metal halides and perchlorates are dissolved in amino group-containing polyalkylene oxide. Polymer temperature sensitive body comprising the above polyamide resin composition.