JPH10140004A - Resin composition for polymer temperature sensing element and polymer temperature sensing element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer temperature sensing element having improved temperature dependence and long term stability, without change by moisture absorption and further having high sensitivity and reliability. SOLUTION: This resin composition for a polymer temperature sensing element comprises a polyamide resin (e.g. polyamide 11 or polyamide 12 alone, or a copolymer thereof) and an olefinic resin (e.g. a modified olefinic resin modified by an epoxy group, a carboxyl group, acid anhydride group, etc.). The proportion of the olefinic resin based on 100 pts.wt. polyamide resin is about 0.1-60 pts.wt. The resin composition can further include about 0.01-10 pts.wt. conductivity-imparting agent (e. g. the conductivity imparting agent constituted of a polyalkylene oxide and a metal salt) based on 100 pts.wt. polyamide resin. Further, the resin composition can include about 0.1-40 pts.wt. phenol resin based on 100 pts.wt. polyamide resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer thermosensitive material useful as a polymer thermosensitive material used for temperature detection for controlling the temperature of a sheet heating element such as an electric blanket and an electric carpet, and a high temperature thermosensitive material. The present invention relates to a method for producing a molecular thermosensor.

[0002]

2. Description of the Related Art As a temperature-sensitive element of a planar heating device such as an electric carpet, a polymer material having electric characteristics having temperature dependence is used. In this polymer material for a thermosensitive polymer, a temperature control circuit is operated by utilizing characteristics such as a dielectric constant, a DC resistance, and an impedance that change with temperature. Properties required for such a polymer thermosensitive material include (1) that the electrical properties of the polymer exhibit high temperature dependence, (2) that the electrical properties of the polymer do not change with time, 3) low hygroscopicity or little change in electrical properties even when moisture is absorbed; and (4) excellent mechanical properties such as flex resistance. Polyamide resin is
It is suitable as a heat-sensitive material because it has a large temperature dependence of the above-mentioned electrical characteristics and excellent mechanical properties and moldability. Particularly, a resin composition of nylon 11 and nylon 12 having low hygroscopicity is preferable.

[0003] In order to improve the temperature dependence of electrical characteristics, JP-A-48-6648, JP-A-48-99691, and JP-A-61-2303 disclose a phenolic compound in a polyamide resin. It is disclosed to be compounded. In such a resin composition, although the effect of improving the electric characteristics is recognized, when used for a long period of time, the electric characteristics change over time due to decomposition and volatilization of the added phenolic compound. Also, phenolic compounds alone are not sufficient to improve the temperature dependence of impedance. JP-A-52-27594, JP-A-58-215449
JP-A-60-106101 discloses that a polyamide resin is mixed with a metal salt as a conductivity-imparting agent. This resin composition, even if the initial temperature dependence of impedance is relatively good, not only varies the sensitivity due to the low compatibility of salts with the polyamide resin, but also the current applied when used as a thermosensitive material. , A polarization phenomenon occurs due to the DC component, and the electrical characteristics change.

On the other hand, JP-A-6-5175 and JP-A-6-124805 disclose the use of a polymer complex-based conductivity imparting agent in which lithium perchlorate is dissolved in polyethylene oxide as the conductivity imparting agent. Is disclosed. When such a conductivity-imparting agent is used, the temperature dependency of impedance is large and the long-term impedance change with time is relatively small as compared with the case where only a phenolic compound or a metal salt is used. However, a conductivity-imparting agent composed of a polyalkylene oxide or an oligomer or polymer of a derivative containing a polyalkylene oxide unit and a metal salt has a high hygroscopic property. The indicated temperature fluctuates greatly. As described above, a polymer material that satisfies all the characteristics required for a polymer thermosensitive material has not been obtained.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin composition for a polymer thermosensitive body having excellent initial thermistor characteristics (impedance characteristics) and stable electric characteristics over a long period of time. It is to provide a polymer thermosensor. Another object of the present invention is to provide a resin composition for a polymer thermosensitive body and a polymer thermosensitive body, which are less sensitive to moisture absorption, have high sensitivity and high reliability.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, have converted olefin resin (particularly, modified olefin resin for improving compatibility with nylon) into polyamide resin. By using the compounded resin composition (polymer alloy), the initial thermistor characteristics and the long-term stability of the electrical characteristics are not impaired.
The inventors have found that the variation in impedance and the variation in temperature due to moisture absorption and drying are small, and completed the present invention.

That is, the fat composition for a polymer thermosensitive body (polymer alloy) of the present invention comprises a polyamide resin and an olefin resin. In this resin composition for a thermosensitive polymer, the concentration of the amide group of the polyamide resin may be about 2 to 14 on average per 100 carbon atoms. The olefin resin can be composed of at least a modified olefin resin, and the ratio of the olefin resin is about 0.1 to 60 parts by weight based on 100 parts by weight of the polyamide resin. The resin composition for a polymer thermosensitive body includes polyamide 1
1 to 50 parts by weight of a modified olefin resin into which at least one functional group selected from an epoxy group, a carboxyl group and an acid anhydride group has been introduced, based on 100 parts by weight of a homopolymer or a copolymer of 1 or polyamide 12 The constituted resin composition is also included. The resin composition may further include a conductivity imparting agent. As a conductivity-imparting agent, a conductivity-imparting agent (mixture or complex) composed of a compound containing a polyalkylene oxide unit [polyalkylene oxide or a derivative (oligomer or polymer) containing a polyalkylene oxide unit] and a metal salt
The use of is extremely effective in that temperature dependency and long-term stability can be improved while suppressing changes in properties during moisture absorption and drying. The ratio of the conductivity-imparting agent is about 0.01 to 10 parts by weight based on 100 parts by weight of the polyamide resin. The resin composition may further contain a phenol resin. The content of the phenol resin is 100% of the polyamide resin.
It is about 0.1 to 40 parts by weight based on parts by weight. The polymer thermosensitive body of the present invention is composed of the resin composition, that is, a polyamide resin and an olefin-based resin. In addition,
In the present specification, the olefin-based resin is not limited to the unmodified olefin-based resin and the modified olefin-based resin, but also includes a resin (for example, a diene-based resin) using an aliphatic unsaturated hydrocarbon-based monomer and an elastomer. Used in

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polymer thermosensor of the present invention comprises a polyamide resin and an olefin resin,
If necessary, an additive such as a conductivity imparting agent or a phenol resin may be contained. Hereinafter, these components will be described.

[Polyamide Resin] The type of polyamide resin that can be used in the resin composition for a thermosensitive polymer of the present invention is not particularly limited, and examples thereof include aliphatic polyamides (polyamide 6, polyamide 9, polyamide 11, polyamide 12). ,
Polyamide 4-6, Polyamide 4-10, Polyamide 6
-6, polyamide 6-10, polyamide 6-11, polyamide 6-12, polyamide 11-12, copolyamide obtained by copolymerizing these polyamide raw materials, etc., and aromatic polyamide (for example, metaxylylenediamine and Polyamide MXD- formed by reaction with adipic acid
6, an amorphous aromatic polyamide produced by the reaction of terephthalic acid and trimethylhexamethylenediamine, a modified polyamide resin (polyamide containing dimer acid or hydrogenated dimer acid as an acid component, N-alkoxymethylated polyamide, N -Alkyl-substituted polyamides), polyamide elastomers (such as impact-resistant polyamides obtained by graft copolymerization of a modified polyolefin, polyetheramides having a polyether as a soft segment), and polyetheresteramides. These polyamide resins can be used alone or in combination of two or more. Preferred polyamide resins are aliphatic polyamide resins, particularly those having low water absorption and excellent electrical properties. Such polyamide resins include:
Long chain aliphatic hydrocarbon group (e.g., C _10-36 aliphatic hydrocarbon group, preferably a C _{11- 36} aliphatic hydrocarbon group) a polyamide resin having, among them carbon atoms per 100 amide groups (-CONH-) Has an average concentration of 14 or less (for example,
(On average about 2 to 14, preferably 2 to 10 on average)
Of polyamide resin. Preferable examples of the polyamide resin include, for example, polyamide 6-10, polyamide 6-11, polyamide 6-12, polyundecaneamide (polyamide 11), polydodecaneamide (polyamide 12), polyamide 11-12, N- Examples thereof include polyamides such as alkyl-substituted polyamides, polyetheramides, polyetheresteramides, polyamides containing dimer acid and / or hydrogenated dimer acid, and copolymers thereof. Particularly, the polyamide resin is a homo- or copolymer of polyamide 11 or polyamide 12 (polyamide 11).
Or a structural unit of polyamide 12).

The number average molecular weight of these polyamide resins is, for example, 5,000 or more (for example, 0.7 × 10 ⁴ to
About 100 × 10 ⁴ ), preferably 1 × 10 ⁴ or more (for example, about 2 × 10 ⁴ to 50 × 10 ⁴ ). The melting point of the polyamide resin is, for example, about 150 to 250 ° C.

These polyamide resins can be prepared by a conventional method,
For example, it can be produced by a method such as ring-opening polymerization of a lactam, condensation polymerization of an aminocarboxylic acid, condensation polymerization of a dicarboxysan component and a diamine component, and a copolymerization method combining these methods.

[Olefin-Based Resin] The polymer thermosensitive material of the present invention is composed of a polyamide resin and an olefin-based resin, and seems to form a polymer alloy. The olefin resin may be either an unmodified olefin resin or a modified olefin resin as long as it can form a polymer alloy with the polyamide resin. The structure of the olefin resin is not particularly limited, and various olefin resins used as molding materials can be used. Examples of the olefin-based resin include polyolefins (e.g., homo- or copolymers of olefins such as ethylene, propylene, methylpentene-1 and butene, for example, polyethylene, polypropylene, ethylene-propylene copolymer, polymethylpentene-1, polybutene). And olefins and copolymerizable monomers (such as acrylates and vinyl monomers) (ionomers, ethylene-
(Meth) acrylic acid copolymer, ethylene- (meth) acrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, etc.), polyolefin rubber or elastomer (ethylene-propylene rubber ( EPDM), ethylene-butadiene-styrene block copolymer rubber, etc.), chlorinated polyolefin (chlorinated polyethylene, chlorinated polypropylene, etc.), diene resin (polybutadiene, styrene-butadiene copolymer (SB resin), styrene) Examples thereof include butadiene-acrylonitrile copolymer (ABS resin), and elastomers (acrylic rubber, nitrile rubber, etc.). When an unmodified olefin-based resin is used, a compatibilizer (for example, an oxazoline compound) may be used in combination to increase the compatibility with the polyamide resin.

From the viewpoint of compatibility with the polyamide resin, the olefin resin is preferably composed of at least a modified olefin resin. The functional group introduced into the modified olefin-based resin includes various functional groups, particularly an epoxy group (or glycidyl group), a carboxyl group, an acid anhydride group, and the like. These functional groups may be introduced alone or in combination of two or more. More specifically, an epoxy-modified olefin resin modified with an epoxy-containing monomer such as glycidyl (meth) acrylate (for example, glycidyl (meth) acrylate-modified polyethylene, etc.), and a carboxyl group-containing such as (meth) acrylic acid and maleic acid Carboxyl group-modified olefin resins modified with monomers (eg, (meth) acrylic acid-modified polyethylene, (meth) acrylic acid-modified polypropylene, maleic acid-modified polypropylene, carboxyl group-modified nitrile rubber, etc.), and acid anhydrides such as maleic anhydride Anhydride-modified olefin resin modified with an anhydride group-containing monomer (for example, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified EPDM, maleic anhydride-modified styrene-buta Ene copolymers, maleic acid-modified hydrogenated styrene anhydride - butadiene copolymer) and the like. Among the modified olefin-based resins, epoxy-modified olefin-based resins are available from Sumitomo Chemical Co., Ltd. under the trade name “Bond First”,
Available from Nippon Oil Co., Ltd. under the trade name “Rex Pearl” and the like. The acid anhydride group-modified olefin resin and the carboxyl group-modified olefin resin can be obtained, for example, from Sumitomo Chemical Co., Ltd. under the trade name “Bondane” in Japan. Sanyo Chemical Co., Ltd. as trade name "N-Polymer" from Petroleum Corporation, trade name "Exceler" from Exxon Corporation, and trade name "Tuffmer" from Mitsui Petrochemical Co., Ltd.
Available from Shell Chemical Co., Ltd. under the trade name "Clayton G"; Asahi Kasei Corporation under the trade name "Tuftec"; from Nippon Oil & Fats Co., Ltd. under the trade name "Modupar".

When an olefin resin incompatible with the polyamide resin is used, these modified olefin resins can be used as a compatibilizer between the unmodified olefin resin and the polyamide resin. The ratio of the modified olefin-based resin to the modified olefin-based resin is in a wide range, for example, the former / the latter = about 5/95 to 95/5 (weight ratio), preferably about 10/90 to 90/10 (weight ratio). You can choose from a range.

The proportion of the olefin resin is 0.1 to 60 parts by weight (for example, 0.5 to 50 parts by weight), preferably 1 to 50 parts by weight (for example, 5 parts by weight) per 100 parts by weight of the polyamide resin. To 50 parts by weight), more preferably about 1 to 40 parts by weight (for example, 5 to 40 parts by weight). If the proportion of the olefin-based resin is too large, the domain of the olefin-based resin and the domain of the polyamide resin are largely separated, and the initial impedance characteristics are lowered, and the long-term stability of the electric characteristics is easily impaired. In addition, since the polymer thermosensor used for the sheet heating element is required to function as a thermal fuse when overheating, if the amount of the olefin resin is too large, an appropriate melting point range for functioning as a thermal fuse is required. The melting point is lower than that, which is not preferable. On the other hand, when the ratio of the olefin-based resin is too small, it is difficult to suppress a change in characteristics due to water absorption.

[Conductivity imparting agent] An additive (conductivity imparting agent) for imparting conductivity may be added to the resin composition of the present invention. The type of the conductivity-imparting agent is not particularly limited, and a conventional conductivity-imparting agent, for example, a metal salt, a compound containing a polyalkylene oxide unit / metal salt complex, or the like can be used. As the metal salt, various salts capable of imparting conductivity can be used. For example, copper salts (copper acetate, copper salicylate, copper benzoate, copper sulfate, copper iodide, etc.), metal iodides (lithium iodide, iodine) Alkali metal iodides such as potassium iodide and sodium iodide, alkaline earth metal iodides such as calcium iodide, the above-mentioned copper iodide, zinc iodide and the like, metal halides (stannic chloride, stannic chloride, etc.) Examples thereof include ferric chloride) and perchlorates (eg, alkali metal perchlorates such as lithium perchlorate, potassium perchlorate, and sodium perchlorate).

The compound containing a polyalkylene oxide unit includes not only a polyalkylene oxide but also a derivative (oligomer or polymer) containing a polyalkylene oxide unit (hereinafter, these may be simply referred to as a polyalkylene oxide). is there),
The conductivity-imparting agent composed of these polyalkylene oxides and metal salts has a large temperature dependence (sensitivity) of impedance and a high long-term stability. As the polyalkylene oxide, a homopolymer or copolymer of C _2-5 alkylene oxide, for example, polyethylene oxide (polyoxyethylene glycol), polypropylene oxide (polyoxypropylene glycol), polybutylene oxide (polyoxybutylene glycol) ,
Examples include polytetramethylene glycol (polyoxytetramethylene glycol), ethylene oxide-propylene oxide block copolymer, and the like. Derivatives (oligomers, polymers) containing polyalkylene oxide units include compounds having active hydrogen atoms [polyhydric alcohols (glycerin, pentaerythritol, sorbitol, etc.), glycerin fatty acid esters,
Sucrose fatty acid esters, phenols (phenols, alkylphenols, etc.), etc.] to which an alkylene oxide has been added, or a polymer having a polyalkylene oxide unit obtained by using the alkylene oxide or polyalkylene oxide (for example, a polydiol as a diol component). Polyurethanes and polyesters using alkylene glycols, polyamides using polyoxyalkylene diamines, homo- or copolymers of polyalkylene glycol mono (meth) acrylate, polyolefins graft-polymerized with polyalkylene oxide, and the like are included. The polyalkylene oxide unit preferably contains at least a polyoxyethylene unit.

More specifically, a mixture or complex (or polymer electrolyte) of a polyalkylene glycol and a metal salt (such as lithium perchlorate), a nonionic surfactant having a polyalkylene oxide unit, and a metal salt are used. Or a mixture or complex of a polymer having a polyalkylene oxide unit (polyurethane, polyester, polyamide, polyacrylate, polyolefin) and a metal salt. The amount of the metal salt used relative to the compound having a polyalkylene oxide unit is about 0.1 to 100 parts by weight, preferably about 1 to 80 parts by weight, more preferably about 5 to 50 parts by weight based on 100 parts by weight of the polyalkylene oxide unit. It is.

The amount of these conductive agents used is, for example, 0.01 to 1 with respect to 100 parts by weight of the polyamide resin.
0 parts by weight, preferably about 0.1 to 5 parts by weight, and more preferably about 0.1 to 2.5 parts by weight (for example, about 0.5 to 2.5 parts by weight).

[Phenolic Resin] In order to improve the electrical properties of the polymer thermosensor, a phenol resin is added to a resin composition containing a polyamide resin, an olefin resin and, if necessary, a conductivity-imparting agent. You may. In particular, a polymer alloy of an olefin-based resin and a polyamide resin is used as a base material of the polymer thermosensitive material, and as a conductivity-imparting agent,
When a mixture or complex of a metal salt, a polyalkylene oxide or a derivative (oligomer, polymer) containing a polyalkylene oxide unit and a metal salt is used, the temperature dependency of impedance can be further improved by blending a phenol resin. At the same time, the impedance can be prevented from changing with time.

The type of the phenol resin is not particularly limited.
For example, by reacting phenols [phenol, p- or m-cresol, 3,5-xylenol, p-alkylphenol (for example, nonylphenol), etc.], oxybenzoic acid [p-oxybenzoic acid alkylester, etc.] with formaldehyde. Examples of the phenol resin include a novolak-type phenol resin and a resol-type phenol resin, and a phenol resin having an alicyclic skeleton generated by a reaction between cycloalkenes, dicyclopentadiene and phenols.

The amount of the phenol resin to be added can be selected from a wide range which does not impair the temperature dependence of electric characteristics, moisture resistance and the like.
It is about 40 parts by weight, preferably about 0.5 parts by weight to 30 parts by weight, and more preferably about 1 to 20 parts by weight. If the amount of the phenol resin used is too large, the linearity of the temperature-dependent characteristic of the impedance is impaired, and the long-term impedance stability is impaired.

[Other Additives] The resin composition for a polymer thermosensitive material and the polymer thermosensitive material of the present invention may contain a stabilizer, for example, an antioxidant for improving heat resistance and weather resistance, and ultraviolet absorption. Agents, heat stabilizers (phenol-based, sulfur-based, amine-based,
Phosphorus-based compounds). Several stabilizers may be used in combination. Further, the resin composition and the polymer thermosensor may contain a flame retardant, an antistatic agent, a plasticizer, a colorant, and the like.

[Production method] The resin composition for a polymer thermosensitive body and the polymer thermosensitive body of the present invention are prepared by melt-kneading the polyamide resin, olefin resin, and, if necessary, a conductivity-imparting agent and a phenol resin. Can be obtained. The polymer thermosensor can be usually used by molding the resin composition into a predetermined shape such as a film or a sheet. The polymer thermosensitive element seems to form a polymer alloy in which the polyamide resin and the olefin-based resin are complexed. By attaching an electrode to the polymer thermosensitive element and applying a current, the temperature of the electrical characteristics is increased. The temperature can be detected using the dependency.

[0025]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples. Preparation of conductivity imparting agent 1 18 parts by weight of sodium thiocyanate, bisphenol A
162 parts by weight of an ethylene oxide adduct (trade name: Newpol BPE180, manufactured by Sanyo Chemical Industries, Ltd.) was placed in a container, and the mixture was stirred using a homomixer at about 2500 rpm for about 1 hour until the solution became completely transparent. A conductivity-imparting agent (NaSCN / bisphenol A ethylene oxide adduct) in which sodium thiocyanate was dissolved in polyethylene glycol was prepared.

The conductivity-imparting agent No. 2 Reactor equipped with stirrer, cooling pipe and nitrogen inlet pipe (volume 2
L) was charged with 122 g of isophorone diisocyanate and 0.5 g of dibutyltin dilaurate (DBTDL), and heated to 60 ° C. while stirring. Then, a mixture of 549 g of polypropylene glycol (molecular weight: 2,000) and 329 g of polyethylene glycol (molecular weight: 600) was dropped in about 3 hours, and the temperature was further raised to 70 ° C. and aged for 4 hours to give a free isocyanate content of 0.2%. React until
A polyalkylene oxide unit-containing polyurethane was prepared. 83.5 parts by weight of the polyalkylene oxide unit-containing polyurethane, 16.5 parts of lithium iodide
Put the parts by weight in a container, and use a homomixer for about 2500 r.
The mixture was stirred for about 1 hour at pm until the solution became completely transparent, to prepare a conductivity-imparting agent (LiI / polyalkylene oxide unit-containing polyurethane) in which lithium iodide was dissolved in the base polyurethane.

The conductivity imparting agent No. 3 Polyalkylene oxide-grafted polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name: Smide 300G) (86.9 parts by weight) was placed in a container, and heated and melted at 80 ° C. Then, 13.1 parts by weight of lithium perchlorate was added and gently mixed and sufficiently dispersed, and then, using a homomixer, about 2500 rpm
m, mix thoroughly for about 3 hours until completely clear,
A conductivity imparting agent (LiClO ₄ / Smide 300G) was prepared. The product was a waxy solid at room temperature.

The conductivity imparting agent No. 4 86.9 parts by weight of a polyalkylene glycol (manufactured by NOF CORPORATION, trade name: Unilube 80DE-40E, polyethylene oxide, polypropylene oxide copolymer) was placed in a container, and heated and melted at 80 ° C. Then
After adding 13.1 parts by weight of sodium iodide and stirring and mixing, the mixture was stirred at high speed using a homomixer at about 2500 rpm for about 3 hours until the mixture became completely transparent, and the conductivity imparting agent (NaI /
(Polyalkylene glycol) was prepared. The product was a viscous liquid at room temperature.

Examples 1 to 5 and Comparative Examples 1 and 2 The following polyamide resin, the above-mentioned conductivity-imparting agent No. 1 to N
o. 4. The following modified olefin resin and additives [modified phenol resin (phenolated dicyclopentadiene,
Nippon Oil Co., Ltd., Nippon Oil special phenolic resin DPP type), antioxidant, heat stabilizer] in the ratio (parts by weight) shown in Table 1, and melt-kneaded at 210 ° C. with an extruder.
Pelletized with a pelletizer. [Polyamide resin] Polyamide resin A: Nylon 12 (manufactured by Daicel Huls Co., Ltd., trade name: Daiamide L1901) Polyamide resin B: Nylon 12 elastomer (manufactured by Daicel Huls Co., Ltd., trade name: Daiamide PAEX)
4442) Polyamide resin C: hydrogenated dimer acid-modified nylon 12
(Product name: Daiamide Z manufactured by Daicel Huls Co., Ltd.)
7379) [Modified olefin resin] Modified olefin resin A: maleic anhydride-modified polyethylene-polypropylene copolymer (Exxer VA1801 manufactured by Exxon) Modified olefin resin B: Glycidyl methacrylate-modified polyethylene (Sumitomo Chemical Industries, Ltd.) Modified olefin resin C: Maleic anhydride-modified polyethylene (N Polymer A1600, manufactured by Nippon Oil Co., Ltd.) Modified olefin resin D: Maleic anhydride-modified ethylene-butene copolymer (Mitsui Petrochemical Co., Ltd.) ), Tuffmer M
P0610) Modified olefin resin E: maleic anhydride-modified ethyl acrylate-ethylene copolymer (Sumitomo Chemical Co., Ltd.)
Made, Bondine AX8390)

[0030]

[Table 1] [Temperature Dependency] The obtained pellet was processed into a film having a thickness of about 0.5 mm at 210 ° C, a tin electrode was mounted thereon, and the impedance at each temperature (30 to 120 ° C) was determined by LC.
It was measured with an R meter (Yokogawa-Hewlett-Packard). The evaluation results of Examples 1 to 5 are shown in FIGS.

[Humidity Dependency] The films of Examples 3 and 4 containing a modified olefin resin and Comparative Examples 1 and 2 containing no modified olefin resin.
The impedance at each temperature was measured by the same measurement method as described above for the case of drying in an oven at 100 ° C. for 2 hours and the case of controlling the humidity at 60 ° C. for 20 hours in a thermo-hygrostat. The results are shown in FIGS.
Table 1 shows the water absorption of the sample.

[Long-term stability] The films of Example 3 and Comparative Example 1 were allowed to stand in an oven at 80 ° C for a long time, and the change with time of the impedance (measuring temperature 30 ° C) was measured. FIG. 6 shows the results.

As is clear from the above results, the resin composition for a temperature sensing element of the present invention can significantly change the volume specific impedance without impairing the properties of the conductivity-imparting agent by blending the modified olefin resin. As shown, high detection sensitivity was obtained with respect to temperature change. Further, the change in impedance between moisture absorption and drying is small, the water absorption rate is small, and the variation in detected temperature is small even under a wide range of humidity conditions.
Further, even in a long-term test at 80 ° C., a change in impedance is small, and a stable temperature detection characteristic is exhibited over a long period.

[0034]

Since the resin composition and the polymer thermosensitive material of the present invention are composed of a polyamide resin and an olefin resin, the impedance has a high temperature dependency, and even if the temperature is high, the impedance is high for a long time. It shows stable electrical characteristics over a long period of time. Further, there is little change in electrical characteristics due to moisture absorption. for that reason,
Even with the use of a conductivity-imparting agent having a large variation in impedance due to water absorption (such as a conductivity-imparting agent composed of a polyalkylene oxide derivative and a metal salt), it is possible to improve the properties of the resin composition for a polymer thermosensor, High sensitivity and high reliability. Further, the resin composition for a polymer thermosensitive body and the polymer thermosensitive body of the present invention have an appropriate melting point, also have a function as a temperature fuse, and have high mechanical properties required for a heat-sensitive wire. .

[Brief description of the drawings]

FIG. 1 is a graph showing the measurement results of the temperature dependence of the initial impedance in the polymer thermosensors of Examples 1 and 2.

FIG. 2 is a graph showing the measurement results of the temperature dependence of the initial impedance in the polymer thermosensors of Examples 3 and 4.

FIG. 3 is a graph showing the measurement results of the temperature dependence of the initial impedance in the polymer thermosensor of Example 5.

FIG. 4 is a graph showing the results of measuring the moisture absorption dependence of the polymer thermosensors of Example 3 and Comparative Example 1.

FIG. 5 is a graph showing the results of measuring the moisture absorption dependence of the polymer thermosensors of Example 4 and Comparative Example 2.

FIG. 6 is a graph showing measurement results of a change over time in impedance of the polymer thermosensors of Example 3 and Comparative Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01C 7/02 H01C 7/02 // (C08L 77/00 23:00 71:02 61:06)

Claims (11)

[Claims] 1. A resin composition for a polymer thermosensitive body, comprising a polyamide resin and an olefin resin. 2. The resin composition for a polymer thermosensitive body according to claim 1, wherein the concentration of the amide group in the polyamide resin is 2 to 14 on average per 100 carbon atoms. 3. The resin composition for a polymer thermosensitive body according to claim 1, wherein the olefin resin comprises at least a modified olefin resin. 4. The resin composition for a polymer thermosensitive body according to claim 1, wherein the proportion of the olefin resin is 0.1 to 60 parts by weight based on 100 parts by weight of the polyamide resin. 5. A modified olefin resin in which at least one functional group selected from an epoxy group, a carboxyl group and an acid anhydride group is introduced into 100 parts by weight of a homopolymer or a copolymer of polyamide 11 or polyamide 12. 1 to
The resin composition for a polymer thermosensitive body according to claim 1, which is composed of 50 parts by weight. 6. The resin composition for a polymer thermosensitive body according to claim 1, further comprising a conductivity imparting agent. 7. The resin composition for a polymer thermosensitive body according to claim 6, wherein the conductivity-imparting agent is a mixture or a complex of a compound containing a polyalkylene oxide unit and a metal salt. 8. The resin composition for a polymer thermosensitive body according to claim 6, wherein the proportion of the conductivity-imparting agent is 0.01 to 10 parts by weight based on 100 parts by weight of the polyamide resin. 9. The resin composition for a polymer thermosensitive body according to claim 1, further comprising a phenol resin. 10. The resin composition for a polymer thermosensitive body according to claim 9, wherein the proportion of the phenol resin is 0.1 to 40 parts by weight based on 100 parts by weight of the polyamide resin. 11. A polymer thermosensitive body composed of a polyamide resin and an olefin-based resin.