JPWO2015178337A1 - Surface resistance heating element, resistance heating seamless tubular material, and resin solution containing conductive particles - Google Patents

Abstract

An object of the present invention is to provide a sheet resistance heating element (including a resistance heating seamless fixing belt) that can be used for a relatively long period of time with a sufficiently small resistance value variation and strength decrease with use. An object of the present invention is to provide a planar resistance heating element (including a resistance heating seamless fixing belt) that can be reduced in size while having a small change in resistance value. The sheet resistance heating element 100, 100a, 100b according to the present invention includes a heat generating resin layer 112 and a pair of electrode portions 120. Then, this sheet resistance heating element is calculated by dividing the resistance value between the electrode parts when the temperature has passed for 300 hours at 300 ° C. by subtracting the initial resistance value between the electrode parts by the initial resistance value. The resistance value variation rate is within a range of ± 30%.

Description

  The present invention relates to a planar resistance heating element and a resistance heating seamless tubular body. The present invention also relates to a conductive particle-containing resin solution.

  In the past, “a resistance heat-generating seamless fixing belt having a heat-generating layer made of a polyimide resin in which carbon nanomaterials and filamentous metal fine particles are dispersed” has been proposed (see, for example, JP-A-2007-272223). This resistance heating seamless fixing belt is a seamless fixing belt that self-heats when energized, and is used as a main part of an image fixing unit of an electrophotographic image forming apparatus.

  However, when metal fine particles such as copper, silver, and nickel are used as the conductive material in the heat generating layer of such a resistance heat generating seamless fixing belt, the metal fine particles gradually change with the use of the electrophotographic image forming apparatus. The resistance value of the resistance heat generating seamless fixing belt gradually changes with the alteration, and the heat generation amount changes accordingly. For this reason, such a resistance heating seamless fixing belt must be replaced in a relatively short period of time.

  In order to solve such a problem, “resistance heating seamless fixing belt using a specific graphite fiber and carbon black or carbon nanofiber as a conductive material” has been proposed in the past (for example, Japanese Patent Application Laid-Open No. 2013-2013). -037213 etc.). In this resistance heating seamless fixing belt, as described above, carbon-based fine particles are used as the conductive material instead of the metal fine particles. Such a resistance heat generation seamless fixing belt exhibits a stable heat generation characteristic with almost no change in resistance value even after long-term use.

JP 2007-272223 A JP 2013-037213 A

  However, in such a resistance heating seamless fixing belt, since graphite particles having a relatively large size are added to the resin, there is a concern that the strength of the resistance heating seamless fixing belt may be reduced. Therefore, after all, there is a possibility that this resistance heat generating seamless fixing belt must be replaced in a relatively short period of time.

  In addition, when carbon-based fine particles are used instead of metal fine particles in the resistance heating seamless fixing belt, the resistance value is remarkably increased, and the resistance heating seamless fixing belt cannot be downsized.

  An object of the present invention is to provide a sheet resistance heating element (including a resistance heating seamless fixing belt) that can be used for a relatively long period of time with a resistance value fluctuation and a strength decrease with use being sufficiently small. Another object of the present invention is to provide a planar resistance heating element (including a resistance heating seamless fixing belt) that can be reduced in size while having a small change in resistance value.

  A planar resistance heating element according to one aspect of the present invention includes a heat generating resin layer and a pair of electrode portions. It should be noted that the term “planar” herein may include a sheet form and a tubular form. Further, the planar resistance heating element may be composed of only the heat generating resin layer and the pair of electrode portions, or may be composed of a plurality of layers including the heat generating resin layer and the pair of electrode portions. The electrode portion is preferably disposed on both sides of the heat generating resin layer. Further, when the planar resistance heating element is in the form of a sheet, the electrode portion may be provided so as to be exposed on the front side surface, may be provided so as to be exposed on the back side surface, or may be embedded. Good. When the planar resistance heating element is tubular, the electrode portion may be provided so as to be exposed on the inner peripheral surface, or may be provided so as to be exposed on the outer peripheral surface, or may be embedded. Good. Moreover, a part of the heat generating resin layer may function as an electrode part. The heat generating resin layer may be directly bonded to the electrode part, or may be indirectly bonded to the electrode part via one or a plurality of conductive resin layers. Then, this sheet resistance heating element is calculated by dividing the resistance value between the electrode parts after the 100 hour elapse at a temperature of 300 ° C. by subtracting the initial resistance value between the electrode parts by the initial resistance value. The resistance value variation rate is within a range of ± 30%.

  As described above, this sheet resistance heating element has a resistance value fluctuation rate within a range of ± 30% when 100 hours have passed at a temperature of 300 ° C. For this reason, this sheet resistance heating element has a sufficiently small resistance value variation with use.

  Further, in this planar resistance heating element, the heat generating resin layer can be formed from a resin containing only a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers as a conductive filler. For this reason, such a planar resistance heating element can sufficiently reduce the strength reduction. Accordingly, such a planar resistance heating element can be used for a relatively long period of time because resistance value fluctuations and strength reductions associated with use are sufficiently small.

  In this planar resistance heating element, the heat generating resin layer can be formed from a resin containing conductive particles having a metal surface. In such a case, the resin preferably contains a resistance value stabilizing component. For this reason, the resistance value of such a planar resistance heating element can be reduced. Therefore, such a planar resistance heating element can be miniaturized while the resistance value variation with use is small.

  A planar resistance heating element according to another aspect of the present invention includes a heat generating resin layer and a pair of electrode portions. It should be noted that the term “planar” herein may include a sheet form and a tubular form. Further, the planar resistance heating element may be composed of only the heat generating resin layer and the pair of electrode portions, or may be composed of a plurality of layers including the heat generating resin layer and the pair of electrode portions. The electrode portion is preferably disposed on both sides of the heat generating resin layer. Further, when the planar resistance heating element is in the form of a sheet, the electrode portion may be provided so as to be exposed on the front side surface, may be provided so as to be exposed on the back side surface, or may be embedded. Good. When the planar resistance heating element is tubular, the electrode portion may be provided so as to be exposed on the inner peripheral surface, or may be provided so as to be exposed on the outer peripheral surface, or may be embedded. Good. Moreover, a part of the heat generating resin layer may function as an electrode part. The heat generating resin layer may be directly bonded to the electrode part, or may be indirectly bonded to the electrode part via one or a plurality of conductive resin layers. The sheet resistance heating element is calculated by dividing the resistance value between the electrode parts after 48 hours at a temperature of 300 ° C. by subtracting the initial resistance value between the electrode parts by the initial resistance value. The resistance value variation rate is within a range of ± 15%.

  As described above, this sheet resistance heating element has a resistance fluctuation rate within a range of ± 15% when 48 hours have passed at a temperature of 300 ° C. For this reason, this sheet resistance heating element has a sufficiently small resistance value variation with use.

  Further, in this planar resistance heating element, the heat generating resin layer can be formed from a resin containing only a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers as a conductive filler. For this reason, such a planar resistance heating element can sufficiently reduce the strength reduction. Accordingly, such a planar resistance heating element can be used for a relatively long period of time because resistance value fluctuations and strength reductions associated with use are sufficiently small.

  In this planar resistance heating element, the heat generating resin layer can be formed from a resin containing conductive particles having a metal surface. In such a case, the resin preferably contains a resistance value stabilizing component. For this reason, the resistance value of such a planar resistance heating element can be reduced. Therefore, such a planar resistance heating element can be miniaturized while the resistance value variation with use is small.

  In the above-mentioned planar resistance heating element, is the heat generating resin layer formed of a resin containing only a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers as a conductive filler (hereinafter referred to as “a conductive filler”)? Such a planar resistance heating element is referred to as a “non-metallic nanofiller-containing planar resistance heating element”), and is formed of a resin containing conductive particles having a metal surface (hereinafter referred to as such). Such a planar resistance heating element is preferably referred to as “a planar resistance heating element containing metal surface particles”. As described above, in the latter case, the resin preferably contains a resistance value stabilizing component.

  In other words, the exothermic resin layer is preferably formed from a resin containing a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers but not containing a metallic filler. This is because the reduction in strength of the planar resistance heating element can be sufficiently reduced as described above. The “non-metallic nanofiller” herein does not include those having a diameter of 0.3 μm or more. Moreover, it is preferable that at least one of the carbon nanotube and the carbon nanofiber is a main component of the nonmetallic nanofiller, and it is more preferable that the nonmetallic nanofiller is composed of only the carbon nanotube or the carbon nanofiber. Here, the “main component” means a component occupying 90% by volume or more. The resin may be composed only of a polyimide resin.

  Moreover, in the above-described non-metallic nanofiller-containing planar resistance heating element, the heat generating resin layer preferably has a film thickness of 20 μm or more. If the film thickness of the heat generating resin layer satisfies this condition, even if the film thickness varies slightly, the fluctuation range of the resistance value becomes so narrow that it can be practically used. This is because even if it exists, the calorific value can be stabilized. In addition, when another layer is not provided in this sheet | seat resistance heating element, it is preferable that the film thickness is 50 micrometers or more. Moreover, it is preferable that the upper limit of this film thickness is 200 micrometers.

  Moreover, in the above-mentioned non-metallic nanofiller-containing planar resistance heating element, it is preferable that the volume fraction of the nonmetallic nanofiller with respect to the heat-generating resin layer is in the range of 5% by volume to 100% by volume. This is because good flexibility can be imparted to the planar resistance heating element, and application to a resistance heating seamless tubular object becomes possible. Here, when the volume fraction of the nonmetallic nano filler relative to the exothermic resin layer is 100% by volume, the exothermic resin layer is formed only from the nonmetallic nano filler. In such a case, this planar resistance heating element requires a base layer for supporting the heat generating resin layer.

  Further, in the above-described planar resistance heating element containing metal surface particles, when a resistance value stabilizing component is added, the resistance value stabilizing component includes (a) at least one of an SH group and an SM group containing a nitrogen-containing aromatic. It is preferable to include a compound directly bonded to the heterocyclic ring (where M is a metal or substituted or unsubstituted ammonium) and (b) a compound containing boron (B). Here, the “resistance value stabilizing component” is obtained by heat-treating a resistance value stabilizer of a conductive particle-containing resin solution described later. The “SH group” herein is a mercapto group, and the “SM group” is a “metal salt” or a “substituted or unsubstituted ammonium salt” of a mercapto group. The compound containing boron (B) is, for example, boron oxide. The resistance value stabilizing component contains (c) at least one element of molybdenum (Mo), vanadium (V), tungsten (W), titanium (Ti), aluminum (Al), and niobium (Nb). It is preferable that a compound to be further contained. This is because deterioration of the electrode part and expansion of the electrode part in the metal surface particle-containing planar resistance heating element can be prevented.

  In the above-mentioned planar resistance heating element containing metal surface particles, the resin preferably further contains a carbon nanomaterial. This is because the carbon nanomaterial functions as a resistance adjusting material for the planar resistance heating element. The carbon nanomaterial is preferably composed mainly of at least one of carbon nanotubes and carbon nanofibers. Here, the “main component” refers to a component occupying 90% by volume or more.

  Moreover, in the above-described planar resistance heating element containing metal surface particles, the heat generation resin layer preferably has a thickness of 10 μm or more. If this condition is satisfied, even if there is a slight variation in film thickness, the fluctuation range of the resistance value becomes extremely narrow to withstand practical use, and even if this planar resistance heating element is mass-produced, the amount of generated heat can be reduced. This is because it can be stabilized.

  In the above-described planar resistance heating element containing metal surface particles, the volume fraction of the conductive particles is preferably in the range of 20% by volume to 70% by volume. This is because good flexibility can be imparted to the planar resistance heating element, and application to a resistance heating seamless tubular object becomes possible. This volume fraction is relative to the volume of the resistance exothermic seamless tubular material.

  In the above-mentioned planar resistance heating element, the initial resistance value between the electrode portions is preferably in the range of 5Ω to 150Ω, and more preferably in the range of 15Ω to 75Ω. This is because the resistance exothermic seamless tubular material in a main country or region can exhibit an output of 400 W to 1200 W that can be required in the fixing device. More specifically, when the initial resistance value is within a range of 5Ω to 40Ω, resistance heat generation for countries and regions such as Japan, the United States, Taiwan, etc., with a voltage within a range of 100V to 120V as a single phase. If the initial resistance value is in the range of 30Ω or more and 150Ω or less, it can be used as a seamless tubular product for countries and regions such as European countries that specify a voltage in the range of single phase 200V or more and 240V or less. It can be set as a resistance exothermic seamless tubular thing.

  The conductive particle-containing resin solution according to another aspect of the present invention contains a resin or resin precursor, conductive particles, a resistance value stabilizer, and a solvent. The conductive particles have a metal surface. The “metal” referred to here may be a pure metal or an alloy. Further, the conductive particles may be metal particles formed only from metal or may be core / shell type particles. When the conductive particles are core / shell type particles, the shell is formed of metal. The solvent dissolves the resin or the resin precursor.

  As described above, the conductive particle-containing resin solution contains a resistance value stabilizer. For this reason, the planar resistance heating element (corresponding to the above-mentioned metal surface particle-containing planar resistance heating element) produced from the conductive particle-containing resin solution has a sufficiently small resistance value variation with use. In addition, the conductive particle-containing resin solution contains conductive particles having a metal surface as described above. For this reason, the planar resistance heating element produced from this conductive particle containing resin solution can make the resistance value small. Therefore, by using this conductive particle-containing resin solution, it is possible to produce a small planar resistance heating element with a small resistance value variation with use.

In the above-described conductive particle-containing resin solution, the resistance value stabilizer includes (d) a compound in which at least one of an SH group and an SM group is directly bonded to a nitrogen-containing aromatic heterocyclic ring (where M is a metal Or substituted or unsubstituted ammonium.) And (e) at least boric acid. Here, the “SH group” is a mercapto group, and the “SM group” is a “metal salt” or “substituted or unsubstituted ammonium salt” of a mercapto group. The resistance value stabilizer preferably further includes (f) a polyacid or a salt thereof. This is because deterioration of the electrode part and expansion of the electrode part in the planar resistance heating element can be prevented. The “polyacid” referred to here is composed of MO ₄ tetrahedron, MO ₅ square pyramid, MO ₆ hexahedron, or MO ₅ trigonal bilateral weight as a result of coordination of 4, 5 and 6 oxygen atoms to metal atoms and the like. An inorganic acid composed of basic units. The polyacid is preferably an isopolyacid, and more preferably a heteropolyacid.

  The conductive particle-containing resin solution described above preferably further contains a carbon nanomaterial. This is because the carbon nanomaterial not only functions as a resistance adjusting material for the planar resistance heating element but also functions as a viscosity adjusting material for the conductive particle-containing resin solution. The carbon nanomaterial is preferably composed mainly of at least one of carbon nanotubes and carbon nanofibers. Here, the “main component” refers to a component occupying 90% by volume or more.

  The planar resistance heating element according to another aspect of the present invention is obtained by heating a coating film of the above-described conductive particle-containing resin solution. As described above, the above-described conductive particle-containing resin solution contains a resistance value stabilizer. For this reason, this planar resistance heating element (corresponding to the above-mentioned metal surface particle-containing planar resistance heating element) produced from this conductive particle-containing resin solution has a sufficiently small resistance value variation with use. Moreover, as described above, the conductive particle-containing resin solution contains conductive particles having a metal surface. For this reason, this planar resistance heating element produced from this conductive particle containing resin solution can make the resistance value small. Therefore, the planar resistance heating element can be miniaturized while the resistance value variation with use is small.

  A resistance exothermic seamless tubular article according to another aspect of the present invention includes an exothermic resin layer and a pair of electrode portions. In addition, this resistance exothermic seamless tubular thing may be comprised only from the heat generating resin layer and a pair of electrode part, and may be comprised from the several layer containing a heat generating resin layer and a pair of electrode part. The electrode portion is preferably disposed on both sides of the heat generating resin layer. Moreover, the electrode part may be provided so as to be exposed on the inner peripheral surface, may be provided so as to be exposed on the outer peripheral surface, or may be embedded. Moreover, a part of the heat generating resin layer may function as an electrode part. The heat generating resin layer may be directly bonded to the electrode part, or may be indirectly bonded to the electrode part via one or a plurality of conductive resin layers. And this resistance exothermic seamless tubular thing removes the value which deducted the initial resistance value between the said electrode parts from the resistance value between the electrode parts when 100 hours passed under the temperature of 300 degreeC by the initial resistance value. The calculated resistance value fluctuation rate is within a range of ± 30%.

  As described above, the resistance exothermic seamless tubular product has a resistance value fluctuation rate within a range of ± 30% when 100 hours have passed at a temperature of 300 ° C. For this reason, this resistance exothermic seamless tubular product has a sufficiently small resistance value variation with use.

  Moreover, in this resistance exothermic seamless tubular product, the exothermic resin layer can be formed from a resin containing only a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers. For this reason, such a resistance exothermic seamless tubular product can sufficiently reduce the strength reduction. Therefore, such resistance exothermic seamless tubular objects can be used for a relatively long period of time because resistance value fluctuations and strength reductions associated with use are sufficiently small.

  Moreover, in this resistance exothermic seamless tubular product, the exothermic resin layer can also be formed from a resin containing conductive particles having a metal surface. In such a case, the resin preferably contains a resistance value stabilizing component. For this reason, such a resistance exothermic seamless tubular object can make the resistance value small. Therefore, such a resistance heat generation seamless tubular object can be reduced in size while the resistance value fluctuation accompanying use is small.

  A resistance exothermic seamless tubular article according to another aspect of the present invention includes an exothermic resin layer and a pair of electrode portions. In addition, this resistance exothermic seamless tubular thing may be comprised only from the heat generating resin layer and a pair of electrode part, and may be comprised from the several layer containing a heat generating resin layer and a pair of electrode part. The heat generating resin layer is formed of a resin containing conductive particles having a metal surface. The electrode portion is preferably disposed on both sides of the heat generating resin layer. Moreover, the electrode part may be provided so as to be exposed on the inner peripheral surface, may be provided so as to be exposed on the outer peripheral surface, or may be embedded. Moreover, a part of the heat generating resin layer may function as an electrode part. The heat generating resin layer may be directly bonded to the electrode part, or may be indirectly bonded to the electrode part via one or a plurality of conductive resin layers. And in this resistance exothermic seamless tubular thing, it calculated by dividing the value which deducted the initial resistance value between electrode parts from the resistance value between electrode parts when 48 hours passed at the temperature of 300 degreeC by the initial resistance value. The resistance value variation rate is within a range of ± 15%.

  As described above, the resistance exothermic seamless tubular product has a resistance value fluctuation rate within a range of ± 15% when 48 hours have passed at a temperature of 300 ° C. For this reason, this resistance exothermic seamless tubular product has a sufficiently small resistance value variation with use.

  Moreover, in this resistance exothermic seamless tubular product, the exothermic resin layer can be formed from a resin containing only a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers. For this reason, such a resistance exothermic seamless tubular product can sufficiently reduce the strength reduction. Therefore, such resistance exothermic seamless tubular objects can be used for a relatively long period of time because resistance value fluctuations and strength reductions associated with use are sufficiently small.

  Moreover, in this resistance exothermic seamless tubular product, the exothermic resin layer can also be formed from a resin containing conductive particles having a metal surface. In such a case, the resin preferably contains a resistance value stabilizing component. For this reason, such a resistance exothermic seamless tubular object can make the resistance value small. Therefore, such a resistance heat generation seamless tubular object can be reduced in size while the resistance value fluctuation accompanying use is small.

It is an appearance perspective view of a resistance exothermic seamless tubular object concerning the 1st and 2nd embodiments of the present invention. It is a front view of the resistance exothermic seamless tubular thing concerning the 1st and 2nd embodiment of the present invention. It is a side view of the resistance exothermic seamless tubular thing concerning the 1st and 2nd embodiment of the present invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a simplified block diagram of the fixing device incorporating the resistance heating seamless tubular object according to the first and second embodiments of the present invention. It is CC sectional drawing of FIG. It is a figure which shows a part of manufacturing process of the resistance exothermic seamless tubular body which concerns on the 1st and 2nd embodiment of this invention. It is a longitudinal direction longitudinal cross-sectional view of the resistance heat generation seamless tubular object which concerns on the modification (I) of 1st Embodiment. It is a longitudinal direction longitudinal cross-sectional view of the resistance heating seamless tubular thing which concerns on the modification (J) of 1st Embodiment. It is an electron micrograph of the strand continuous metal particle which can be used suitably in the 2nd Embodiment of this invention.

-First embodiment-
<Configuration of sheet resistance heating element>
The planar resistance heating element according to the first embodiment of the present invention is a sheet-like or tubular resistance heating element. The sheet-like planar resistance heating element is easily formed by cutting a tubular planar resistance heating element along the longitudinal direction. Therefore, here, the details of the planar resistance heating element will be described using the tubular planar resistance heating element (hereinafter referred to as “resistance heating seamless tubular object”) 100 shown in FIG. A description of the resistance heating element will be omitted.

  A resistance heating seamless tubular article 100 according to an embodiment of the present invention is mainly composed of a main body 110 and a pair of electrodes 120 as shown in FIGS. Hereinafter, these components 110 and 120 will be described in detail.

(1) Main Body The main body 110 is mainly composed of a heat generating resin layer 112 and a release layer 113 as shown in FIGS. 4 and 5. Hereinafter, these layers 112 and 113 will be described in detail.

(1-1) Heat generation resin layer The heat generation resin layer 112 is a seamless tubular layer as shown in FIGS. 4 and 5, and can mainly withstand the temperature during use of the resistance heat generation seamless tubular body 100. It is preferably formed from a heat resistant insulating material. Examples of such a heat resistant insulating material include a heat resistant resin. In the resistance heating seamless tubular article 100 according to the present embodiment, the heat-resistant resin is preferably a resin containing a polyimide resin as a main component, and more preferably a polyimide resin itself. When the heat-resistant resin is a resin mainly composed of a polyimide resin, other heat-resistant resins such as polyamide imide and polyether sulfone are added to the heat-resistant resin within the range that does not impair the essence of the present invention. May be.

  In the heat-generating resin layer 112, the heat-resistant resin includes a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers having a diameter of less than 0.3 μm as a conductive filler. In addition, the resistance exothermic seamless tubular article 100 according to the present embodiment does not include a metal nanofiller as the conductive filler. In addition, it is preferable that the length of a carbon nanotube or carbon nanofiber exists in the range of 3 micrometers or more and 20 micrometers or less. The diameter of the carbon nanotube or carbon nanofiber is more preferably in the range of 0.015 μm to 0.20 μm, further preferably in the range of 0.08 μm to 0.15 μm, and more preferably 0.10 μm to 0 It is particularly preferable to be within the range of 15 μm. At least one of the carbon nanotube and the carbon nanofiber is preferably a main component of the nonmetallic nanofiller.

  In the present embodiment, the volume fraction of the nonmetallic nanofiller with respect to the heat generating resin layer 112 is in the range of 5% by volume to 100% by volume, but is in the range of 5% by volume to 70% by volume. Preferably, it is in the range of 15 volume% or more and 60 volume% or less, more preferably in the range of 25 volume% or more and 50 volume% or less, and in the range of 25 volume% or more and 40 volume% or less. It is particularly preferred that Of course, the volume fraction needs to be changed depending on the target resistance value, but if the volume fraction is within this range, the balance between the mechanical characteristics and the heat generation characteristics of the heat generating resin layer 112 is excellent. It is.

  Further, the thickness of the heat generating resin layer 112 is 20 μm or more, preferably 40 μm or more, and more preferably 50 μm or more. If the thickness of the heat generating resin layer 112 satisfies this condition, even if a slight variation occurs in the thickness of the heat generating resin layer 112, the fluctuation range of the resistance value becomes extremely narrow enough to withstand practical use. This is because the amount of heat generated can be stabilized even in the case of production. In consideration of ease of manufacture and flexibility of the resistance heating seamless tubular article 100, the thickness is preferably 200 μm or less, more preferably 100 μm or less, and further preferably 50 μm or less.

  In the present embodiment, it is preferable that the carbon nanotubes or carbon nanofibers in the heat generating resin layer 112 exist in the length direction. This is because the electrical resistance value can be efficiently lowered with a relatively small amount of carbon nanomaterial, and uniform heat generation characteristics can be obtained.

  In the present embodiment, the heat-generating resin layer 112 is provided with alumina, boron nitride, aluminum nitride, silicon carbide, titanium oxide, silica, potassium titanate, alumina, silicon nitride, etc. for the purpose of improving thermal conductivity and the like. For the purpose of improving mechanical properties, etc., potassium titanate fiber, acicular titanium oxide, aluminum borate whisker, tetrapotted zinc oxide whisker, sepiolite, fiber particles such as glass fiber, montmorillonite, Viscous minerals such as talc may be added to such an extent that the essence of the present invention is not impaired.

(1-2) Release Layer The release layer 113 is preferably formed from at least one selected from the group consisting of fluororesin, silicone rubber, and fluororubber. When this resistance heat generation seamless tubular product 100 is used as a heat generation fixing belt in a monochrome printer, the release layer 113 is preferably formed of a fluororesin. Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). It may be used in a mixture or may be used as a mixture. In such a case, the release layer 113 preferably has a thickness in the range of 5 μm to 30 μm, and more preferably in the range of 10 μm to 20 μm.

  The release layer 113 is preferably bonded to the heat generating resin layer 112 through a primer. In such a case, the primer thickness is preferably in the range of 2 μm to 5 μm.

(2) Electrode The electrode 120 is arrange | positioned so that it may be exposed to an outer surface in the both ends of the main body 110, as FIG. 1 shows. The electrode 120 can be formed from, for example, a silver paste or the like. As the silver paste, for example, those disclosed in International Publication No. 08/016148 can be used. When the resistance heating seamless tubular object 100 is used, the electrode 120 is in contact with the power supply member 210 as shown in FIG. As a result, power is supplied to the heat generating resin layer 112 disposed in contact with the electrode 120, and the heat generating resin layer 112 generates resistance heat. Examples of the power supply member 210 include a power supply brush, a power supply roll, and a power supply bar.

<Characteristics of the resistance exothermic seamless tubular article according to the first embodiment>
(1) Initial resistance value The resistance exothermic seamless tubular object 100 according to the first embodiment is intended for countries and regions such as Japan, the United States, Taiwan and the like that have a voltage within a range of a single phase of 100V to 120V. The initial resistance value between the electrodes is preferably adjusted within the range of 5Ω to 40Ω, and countries and regions such as European countries that use a single-phase voltage of 200V to 240V as a standard. When it is directed, it is preferable that the initial resistance value between the electrode portions is adjusted within a range of 30Ω to 150Ω. In the former case, it is more preferable that the initial resistance value between the electrode portions is adjusted within a range of 15Ω to 20Ω. In the latter case, it is more preferable that the initial resistance value between the electrode portions is adjusted within a range of 65Ω to 75Ω. This is because this resistance exothermic seamless tubular product can exhibit an output of 400 W to 1200 W that can be required in a fixing device in major countries and major regions. The initial resistance value of the resistance exothermic seamless tubular object 100 is measured at normal temperature and pressure.

(2) Resistance value fluctuation rate The resistance exothermic seamless tubular article 100 according to the first embodiment has a resistance value fluctuation rate of ± 15 at the time of elapse of 48 hours at a temperature of 300 ° C. by being configured as described above. %, The resistance value fluctuation rate after 100 hours at a temperature of 300 ° C. can be kept within a range of ± 30%, and the resistance value fluctuation after 125 hours at a temperature of 300 ° C. The rate can be kept within a range of ± 30%. In addition, the resistance value fluctuation rate at the time of elapse of 48 hours at a temperature of 300 ° C. is more preferably within a range of ± 10%, and further preferably within a range of ± 7%. Further, the rate of change in resistance value after 100 hours at a temperature of 300 ° C. is more preferably within a range of ± 25%, further preferably within a range of ± 20%, and within a range of ± 15%. More preferably, it is particularly preferably within a range of ± 10%. Further, the resistance value fluctuation rate when 125 hours have passed at a temperature of 300 ° C. is more preferably within a range of ± 25%, further preferably within a range of ± 20%, and within a range of ± 15%. More preferably, it is particularly preferably within a range of ± 10%. The “resistance value fluctuation rate” here is calculated by the following equation 1.

  In the above equation 1, “300 ° C. t time elapsed resistance value” indicates the resistance value of the resistance heating seamless tubular article 100 at 300 ° C. temperature t time elapsed, and “initial resistance value” is room temperature. The initial resistance value of the resistance heating seamless tubular article 100 is shown.

<An example of the manufacturing method of the resistance exothermic seamless tubular article according to the first embodiment>
The resistance exothermic seamless tubular article 100 according to the first embodiment is mainly manufactured through a heat generating resin layer forming step, an electrode forming step, a primer applying step, a release layer forming step, a firing step, and a demolding step. . However, this manufacturing method is only an example and does not limit the present invention. Hereafter, each said manufacturing process is explained in full detail.

(1) Exothermic resin layer molding step In the exothermic resin layer molding step, as shown in FIG. 8, a non-metallic nanofiller-containing polyimide precursor solution VS is made of a cylindrical core body 610 using a ring-shaped die 620. After uniformly apply | coating to an outer peripheral surface, the core body 610 with the coating film CV is heated. The heating temperature at this time is preferably such that the organic polar solvent evaporates but imidization does not proceed, for example, a temperature within the range of 200 ° C. or more and 250 ° C. or less. You may raise to 450 degreeC. In such a case, the carbon nanotubes and carbon nanofibers are aligned in one direction and oriented in the direction in which the ring-shaped die travels.

  The non-metallic nanofiller-containing polyimide precursor solution can be obtained by mixing non-metallic nanofillers such as carbon nanotubes and carbon nanofibers with a polyimide precursor solution prepared as follows. In addition, the addition method of a nonmetallic nanofiller is not specifically limited, Of course, the method of adding a nonmetallic nanofiller directly to a polyimide precursor solution, as well as the nonmetallic nanofiller during the polyimide precursor solution preparation The method of adding may be sufficient.

The polyimide precursor solution is prepared as follows.
First, a diamine solution is prepared by dissolving at least one diamine in an organic polar solvent, and then at least one tetracarboxylic dianhydride is added to the diamine solution to obtain a diamine, a tetracarboxylic dianhydride, Is polymerized to prepare a polyimide precursor solution. At this time, the environmental temperature is preferably in the range of 10 ° C. or higher and 90 ° C. or lower. Moreover, solid content concentration is determined by the conditions of application | coating, and usually exists in the range of 10 to 30 mass%. Further, as the polymerization reaction of diamine and tetracarboxylic dianhydride proceeds, the viscosity of the solution increases. However, it can be used after diluting with a solvent to obtain a desired viscosity. Depending on manufacturing conditions and working conditions, it is usually used at a viscosity of 1 poise to 5,000 poise. In order to apply this polyimide precursor solution to the surface of a mold by a casting method, the viscosity of the polyimide precursor solution is It is preferably within a range of 10 poise or more and 1,500 poise or less, and more preferably within a range of 50 poise or more and 1,000 poise or less.

  Examples of the organic polar solvent capable of preparing the polyimide precursor solution include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, 1 , 3-dimethyl-2-imidazolidinone, N-methylcaprolactam, hexamethylphosphoric triamide, 1,2-dimethoxyethane, diglyme, triglyme and the like. Among these diamines, N, N-dimethylacetamide (DMAC) and N-methyl-2-pyrrolidone (NMP) are particularly preferable. In addition, these organic polar solvents may be used independently and may be used in combination. Moreover, aromatic hydrocarbons, such as toluene and xylene, may be mixed with this organic polar solvent.

  Examples of the diamine capable of preparing the polyimide precursor solution include, for example, paraphenylenediamine (PPD), metaphenylenediamine (MPDA), 2,5-diaminotoluene, 2,6-diaminotoluene, 4,4 ′ -Diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 2,2-bis (trifluoromethyl) -4, 4'- Diaminobiphenyl, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane (MDA), 2,2-bis- (4-aminophenyl) propane, 3,3′-diaminodiphenylsulfone (33DDS), 4, 4′-diaminodiphenyl sulfone (44DDS), 3,3′-diaminodiphenyl sulfide, 4, '-Diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether (34 ODA), 4,4'-diaminodiphenyl ether (ODA), 1,5-diaminonaphthalene, 4,4'-diaminodiphenyl Diethylsilane, 4,4′-diaminodiphenylsilane, 4,4′-diaminodiphenylethylphosphine oxide, 1,3-bis (3-aminophenoxy) benzene (133APB), 1,3-bis (4-aminophenoxy) Benzene (134APB), 1,4-bis (4-aminophenoxy) benzene, bis [4- (3-aminophenoxy) phenyl] sulfone (BAPSM), bis [4- (4-aminophenoxy) phenyl] sulfone (BAPS) ), 2,2-bis [4- (4-a Nophenoxy) phenyl] propane (BAPP), 2,2-bis (3-aminophenyl) 1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) 1, Aromatic diamines such as 1,1,3,3,3-hexafluoropropane, 9,9-bis (4-aminophenyl) fluorene, aliphatic diamines such as tetramethylenediamine and hexamethylenediamine, cyclohexanediamine, isophoronediamine And alicyclic diamines such as norbornanediamine, bis (4-aminocyclohexyl) methane, and bis (4-amino-3-methylcyclohexyl) methane. In addition, even if it uses these diamines in mixture of 2 or more types, it does not interfere at all. Among these diamines, paraphenylenediamine (PPD), metaphenylenediamine (MPDA), 4,4′-diaminodiphenylmethane (MDA), 3,3′-diaminodiphenylsulfone (33DDS), 4,4′- Diaminodiphenylsulfone (44DDS), 3,4'-diaminodiphenyl ether (34ODA), 4,4'-diaminodiphenylether (ODA), 1,3-bis (3-aminophenoxy) benzene (133APB), 1,3-bis (4-aminophenoxy) benzene (134APB), bis [4- (3-aminophenoxy) phenyl] sulfone (BAPSM), bis [4- (4-aminophenoxy) phenyl] sulfone (BAPS), 2,2-bis [4- (4-Aminophenoxy) phenyl] pro Emissions (BAPP) is preferable.

  Furthermore, as the tetracarboxylic dianhydride that can prepare the polyimide precursor solution, pyromellitic dianhydride (PMDA), 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4 , 5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,3 , 3′4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 2,2 ′, 3,3′-benzophenonetetracarboxylic dianhydride Anhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA), bis (3,4-dicarboxyl) Phenyl) sulfone dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ) Ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis [3,4- (dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, oxydiphthalic anhydride (ODPA), bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfoxide Dianhydride, thiodiphthalic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetraca Boronic acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 9,9-bis (3,4-dicarboxyphenyl) fluorene dianhydride and 9,9-bis [4- ( Aromatic tetracarboxylic dianhydrides such as 3,4′-dicarboxyphenoxy) phenyl] fluorene dianhydride, cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,4-dicarboxy-1-cyclohexylsuccinic dianhydride, 3 , 4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride. In addition, even if it uses these tetracarboxylic dianhydrides in mixture of 2 or more types, it does not interfere at all. Among these tetracarboxylic dianhydrides, pyromellitic dianhydride (PMDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 3,3 ′, 4 4,4′-benzophenone tetracarboxylic dianhydride (BTDA), 2,2-bis [3,4- (dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), and oxydiphthalic anhydride (ODPA) are preferred.

  In the present embodiment, it is particularly preferable to use paraphenylenediamine as the diamine and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as the tetracarboxylic dianhydride. Polyimide resins obtained from these monomers are excellent in mechanical properties and tough, and do not soften or melt like thermoplastic resins even when the temperature of the resistance exothermic seamless tubular article 100 rises, and have excellent heat resistance It is because it has.

  Further, if necessary, a resin such as polyamideimide or polyethersulfone may be added to the polyimide precursor solution within a range that does not impair the essence of the present invention.

  In addition, the polyimide precursor solution includes a dispersant, a solid lubricant, an anti-settling agent, a leveling agent, a surface conditioner, a moisture absorbent, an anti-gelling agent, and an antioxidant within the range not impairing the properties of the present invention. Addition of known additives such as UV absorbers, light stabilizers, plasticizers, anti-skinning agents, surfactants, antistatic agents, antifoaming agents, antibacterial agents, antifungal agents, antiseptics, thickeners May be. Furthermore, a stoichiometric or higher dehydrating agent and an imidization catalyst may be added to the polyimide precursor solution.

  The polyimide precursor solution is preferably subjected to a treatment such as filtration and defoaming before use.

(2) Electrode forming step In the electrode forming step, first, a silver paste is applied to the outer peripheral surfaces of both end portions of the heat generating resin layer 112, and then the applied thickness of the silver paste is made uniform by a known method. And the electrode 120 can be shape | molded by heating the core body by which the silver paste was apply | coated to the heat-generating resin layer 112. FIG. In addition, it is preferable that the polyimide precursor is added to silver paste as binder resin. This is because not only the adhesiveness with the heat generating resin layer 112 can be improved, but also the electrode 120 remains firmly bonded to the heat generating resin layer 112 even at high temperatures. As such a silver paste, for example, those disclosed in International Publication No. 08/016148 can be used.

(3) Primer application process In the primer application process, the core liquid 610 on which the heat generating resin layer 112 is formed is dipped in the primer liquid in a state where the electrode 120 is masked, so that the primer liquid is formed on the outer peripheral surface of the heat generating resin layer 112. Evenly applied. And the exothermic resin layer 112 (with core body 610) with the coating film is heated. In addition, it is preferable that the heating temperature at this time is a temperature at which the solvent is volatilized but imidization of the previous polyimide precursor does not proceed, for example, a temperature within a range of 200 ° C. or more and 250 ° C. or less.

(4) Release layer molding process In the release layer molding process, after the fluororesin dispersion liquid is applied in a state where the electrode 120 is masked, the coating film is dried, and fluorine is formed on the primer layer. A coating film of a resin dispersion liquid is formed.

(5) Firing step In the firing step, after the masking is removed, the product obtained in the release layer forming step is fired to obtain the resistance exothermic seamless tubular product 100. The firing temperature at this time is preferably a temperature within the range of 350 ° C. or more and 400 ° C. or less. The treatment time is preferably in the range of 30 minutes to 2 hours. If the imidization of the heat generating resin layer 112 is completed and the fluororesin of the release layer 113 is fired at the same time, the manufacturing time of the resistance heat generating seamless tubular product 100 can be shortened and the thermal efficiency can be improved. This is because the adhesive strength of the layers 112 and 113 can also be increased.

(6) Demolding process In the demolding process, the resistance exothermic seamless tubular object 100 is extracted from the core body 610.

<Fixing device of electrophotographic image forming apparatus>
Here, an embodiment of an image fixing apparatus incorporating the resistance heat generating seamless tubular body 100 according to the first embodiment will be described. The image fixing apparatus can also incorporate a resistance heating seamless tubular article 100 according to a second embodiment to be described later.

  As shown in FIGS. 6 and 7, the image fixing device 400 mainly includes a resistance heating seamless tubular object 100 according to the present embodiment, a belt support 150, a pressure roll 300, and a power supply roll 210. ing.

  The resistance exothermic seamless tubular object 100 is as described above. The belt support 150 is made of a heat-resistant insulating resin such as polyphenylene sulfide, polyamideimide, polyetheretherketone, or liquid crystal polymer, and mainly includes a cylindrical portion 151 and a belt guide portion 152. As shown in FIG. 7, the cylindrical portion 151 is rotatably disposed inside the resistance heating seamless tubular object 100. The belt guide part 152 functions as a stopper when the resistance heating seamless tubular article 100 meanders in the width direction. The pressure roll 300 includes a roll body 310 and a shaft 320. The shaft 320 extends on both sides along the rotation axis of the roll body 310 and is connected to a drive motor (not shown). As shown in FIGS. 6 and 7, the roll body 310 is pressed against the resistance heating seamless tubular object 100, and as a result, a nip portion N is formed between the roll body 310 and the resistance heating seamless tubular object 100. That is, when the drive motor is driven, the roll main body 310 rotates about the rotation axis, and the resistance heating seamless tubular object 100 pressed against the pressure roll 300 is driven. Then, as shown in FIG. 7, the copy paper PP on which the unfixed toner image TN is formed is sequentially fed into the nip portion N, and the unfixed toner image TN is sequentially heat-fixed on the copy paper PP. The The power supply roll 210 is connected to the AC power supply 230 via the lead wire 220 and is in contact with the electrode 120 of the resistance heating seamless tubular object 100. For this reason, electricity is supplied to the resistance heating seamless tubular object 100 from the AC power supply 230 via the power supply roll 210. When the resistance heat generating seamless tubular body 100 is energized, the heat generating resin layer 112 generates resistance heat as described above.

<Characteristics of the resistance heating seamless tubular article according to the first embodiment>
(1)
The resistance exothermic seamless tubular article 100 according to the first embodiment has an exothermic resin layer 112, and the exothermic resin layer 112 has at least one of carbon nanotubes and carbon nanofibers as a main component as a conductive filler. Only the non-metallic nano filler is dispersed in the heat-resistant resin, and does not include a conductive filler having a relatively large size such as graphite fiber or a metallic conductive filler. The resistance exothermic seamless tubular article 100 has a resistance value fluctuation rate within a range of ± 15% when 48 hours have passed at a temperature of 300 ° C., and has a resistance value when 100 hours have passed at a temperature of 300 ° C. Value fluctuation rate is within ± 30%. For this reason, this resistance exothermic seamless tubular object 100 not only has a sufficiently small resistance value variation with use, but also can sufficiently reduce the strength reduction. Therefore, this resistance exothermic seamless tubular object 100 can be used for a relatively long time.

(2)
In the resistance exothermic seamless tubular body 100 according to the first embodiment, the heat generating resin layer 112 has a thickness of 20 μm or more. For this reason, even if a slight variation occurs in the thickness of the heat generating resin layer 112, the fluctuation range of the resistance value becomes extremely narrow enough to withstand practical use. The calorific value can be stabilized.

(3)
In the resistance exothermic seamless tubular article 100 according to the present embodiment, the volume fraction of the nonmetallic nanofiller with respect to the exothermic resin layer 112 is in the range of 5% by volume to 100% by volume. Good flexibility can be imparted to the resistance exothermic seamless tubular article 100.

<Modification>
(A)
Although not particularly mentioned in the first embodiment, a base layer may be provided on the inner peripheral side of the heat generating resin layer 112. The base layer is a seamless tubular layer, and is preferably formed from a heat-resistant insulating material that can withstand the temperature during use of the resistance heating seamless tubular object 100. Examples of such a heat-resistant insulating material include special stainless steel and heat-resistant resin. The heat-resistant resin is preferably a resin mainly composed of a polyimide resin or silicone rubber, and more preferably a polyimide resin itself. In addition, when the resistance heat generating seamless tubular article 100 is incorporated in an image fixing unit of an electrophotographic image forming apparatus as a fixing tube or a fixing belt, it is preferable that the base layer has a mechanical characteristic capable of withstanding the operation. When the base layer is provided on the main body 110 in this way, the heat generating resin layer 112 may have a thickness of 30 μm or more.

(B)
Although not specifically mentioned in the first embodiment, the main body 110 may be formed of only the heat generating resin layer 112.

(C)
In the resistance heating seamless tubular article 100 according to the first embodiment, the electrodes 120 are provided at both ends, but the arrangement positions of the electrodes 120 are not particularly limited, and may be appropriately changed according to the application.

(D)
Although not particularly mentioned in the first embodiment, an elastic layer may be provided between the heat generating resin layer 112 and the release layer 113. The elastic layer is preferably made of at least one rubber selected from the group consisting of silicone rubber and fluorine rubber. This rubber is preferably soft and low in hardness. Specifically, silicone rubber having a JIS-A hardness of 3 to 50 degrees is suitable. The thickness of this elastic layer is preferably in the range of 100 μm or more and 500 μm or less. By providing an elastic layer between the heat generating resin layer 112 and the release layer 113 as described above, the resistance heat generating seamless tubular object 100 can be applied to a full color image fixing application.

(E)
Although not particularly mentioned in the first embodiment, an insulating layer may be provided between the heat generating resin layer 112 and the release layer 113. In such a case, a primer is preferably used between the insulating layer and the release layer 113 in order to stabilize the adhesiveness. In such a case, the insulating layer may be added with a filler for improving thermal conductivity or a filler for improving mechanical properties listed in the column of “(1-1) Heat generation resin layer”. Absent. By forming the insulating layer in this way, the heat quantity of the heat generating resin layer 112 can be efficiently conducted to the outer surface of the resistance heat generating seamless tubular object 100, and thus quick start or energy saving can be realized. It is.

(F)
In the first embodiment, at least one diamine is dissolved in an organic polar solvent to prepare a diamine solution, and then at least one tetracarboxylic dianhydride is added to the diamine solution to add diamine and tetra A polyimide precursor solution was prepared by polymerizing with carboxylic dianhydride, but the method for producing the polyimide precursor solution is not particularly limited, and either a diamine or a tetracarboxylic dianhydride derivative is used. May be. Examples of the tetracarboxylic dianhydride derivatives include ester compounds.

(G)
In the first embodiment, the electrode 120 is disposed so as to be in contact with the heat generating resin layer 112 (see FIG. 5). However, if conductivity is imparted to the release layer 113 and the primer, the electrode 120 is removed from the release layer 113. You may arrange | position so that it may touch.

(H)
In the resistance heating seamless tubular article 100 according to the first embodiment, the electrode 120 is disposed so as to be exposed to the outer peripheral side (see FIG. 5), but if the release layer 113 is provided with conductivity, the electrode 120 may be embedded in the release layer 113.

(I)
In the resistance heating seamless tubular object 100 according to the first embodiment, the electrode 120 is disposed so as to be exposed on the outer peripheral side (see FIG. 5), but like the resistance heating seamless tubular object 100a shown in FIG. In addition, the electrode 120 may be disposed so as to be exposed on the inner peripheral side of the heat generating resin layer 112. Further, as described in the modification example (A), when the base layer is provided on the inner peripheral side of the heat generating resin layer 112, the base layer is provided so that the electrode 120 is exposed on the inner peripheral side. However, the electrode 120 may be embedded in the base layer as long as conductivity is imparted to the base layer.

(J)
In the resistance exothermic seamless tubular object 100 according to the first embodiment, the electrode 120 is disposed on the exothermic resin layer 112 (see FIG. 5), but like the resistance exothermic seamless tubular object 100b shown in FIG. In addition, the electrode 120 may be disposed beside the heat generating resin layer 112. In such a case, when the release layer 113 maintains insulation, the release layer 113 is formed on the heat generating resin layer 112 so that the electrode 120 is exposed on the inner peripheral side or the electrode 120 is exposed on the outer peripheral side. It is formed only on the outer peripheral surface. On the other hand, when conductivity is imparted to the release layer 113, the release layer 113 may cover the electrode 120.

  Further, as described in the modification example (A), when the base layer is provided on the inner peripheral side of the heat generating resin layer 112 and the base layer retains insulation, the electrode 120 is exposed on the outer peripheral side. The release layer 113 is formed only on the outer peripheral surface of the heat generating resin layer 112 (in this case, the base layer may cover the electrode 120), or the base layer is formed so that the electrode 120 is exposed to the inner peripheral side. It is formed only on the inner peripheral surface of the layer 112 (in such a case, the release layer 113 may cover the electrode 120). On the other hand, when conductivity is imparted to the base layer, the base layer may cover the electrode 120.

-Second Embodiment-
The tubular planar resistance heating element according to the second embodiment (hereinafter referred to as “resistance heating seamless tubular material”) is the tubular structure according to the first embodiment only in the configuration of the heat generating resin layer. It differs from the planar resistance heating element. Therefore, hereinafter, only the heat-generating resin layer will be referred to, and description of other configurations will be omitted.

(1-1) Exothermic resin layer The exothermic resin layer 112 is a seamless tubular layer as shown in FIGS. 4 and 5, and mainly withstands the temperature during use of the resistance exothermic seamless tubular body 100. Heat-resistant insulating material to be obtained "," conductive particles having a metal surface (hereinafter referred to as "metal surface conductive particles") "," compound in which at least one of SH group and SM group is directly bonded to a nitrogen-containing aromatic heterocycle (Wherein M is a metal or substituted or unsubstituted ammonium) (hereinafter referred to as “mercapto group-containing nitrogen-containing aromatic heterocyclic compound”) ”and“ boron (B) -containing compound (hereinafter referred to as “boron-containing”). Compound "))". Note that these compounds are essential components of the heat generating resin layer 112 in the resistance heat generating seamless tubular product according to the second embodiment. In the second embodiment, the metal surface conductive particles, the mercapto group-containing nitrogen-containing aromatic heterocyclic compound and the boron-containing compound are contained in the heat-resistant insulating material.

  Further, if necessary, the heat generating resin layer 112 may include “molybdenum (Mo), vanadium (V), tungsten (W), titanium (Ti), aluminum (Al), and niobium (Nb) at least one element. The polyacid-derived compound (hereinafter referred to as “polyacid-derived compound”) ”may be further included, or carbon nanomaterials such as carbon nanotubes and carbon nanofibers may be included as a conductive auxiliary material. Alternatively, for the purpose of improving thermal conductivity, etc., electrically insulating particles such as alumina, boron nitride, aluminum nitride, silicon carbide, titanium oxide, silica, potassium titanate, alumina, silicon nitride may be included. For the purpose of improving mechanical properties, potassium titanate fiber, acicular titanium oxide, aluminum borate whisker, tetrapot acid Zinc whisker, sepiolite, fibrous particles such as glass fiber, montmorillonite, may include clay minerals such as talc. However, these optional components are required to be added to such an extent that the essence of the present invention is not impaired. These optional components are contained in the heat-resistant insulating material. Hereinafter, the above-mentioned essential components and optional components will be described in detail.

(1-1-1) Heat-resistant insulating material Examples of the heat-resistant insulating material include a heat-resistant resin. In the resistance heating seamless tubular article 100 according to the present embodiment, the heat-resistant resin is preferably a resin containing a polyimide resin as a main component, and more preferably a polyimide resin itself. Note that details of the polyimide resin are sufficiently described in the first embodiment, and thus description thereof is omitted. In addition, when the heat-resistant resin is a resin mainly composed of a polyimide resin, other heat-resistant resins such as polyamide imide and polyether sulfone are added to the heat-resistant resin within a range that does not impair the essence of the present invention. May be.

(1-1-2) Metal Surface Conductive Particles The metal surface conductive particles according to the second embodiment are metal particles or conductive particles (hereinafter referred to as “core— This is referred to as “shell-type conductive particles”. When the metal surface conductive particles are core-shell type conductive particles, the cost or weight of the conductive particle-containing resin solution (described later) can be reduced.

In the second embodiment, the metal particles are not particularly limited, but are preferably highly conductive metal particles such as platinum, gold, silver, nickel, and palladium. The metal particles may have any shape such as a scale shape, a needle shape, a dendritic shape, or a filament shape, but a filament shape is preferable because a conductive network can be constructed with a small amount. In the present embodiment, the metal particles are particularly “metal particles having a shape in which strands are three-dimensionally connected” (hereinafter referred to as “strand continuous metal particles”) as shown in FIG. preferable. Such strand continuous metal particles preferably have an average particle diameter in the range of 0.1 μm to 5.0 μm and a specific surface area of 1.0 m ² / g to 100 m ² / g. In addition, when carbon nanomaterials such as carbon nanotubes and carbon nanofibers are used in combination, the strand continuous metal particles can form a low-resistance heating resistor by being intertwined linearly with the carbon nanomaterial, A heat generating resin layer having a uniform volume resistivity can be formed.

  Further, in the present embodiment, the core particle of the core-shell type conductive particle is not particularly limited, but is an inorganic particle such as carbon, glass, ceramics and the like from the viewpoint of characteristics such as cost and heat resistance. Is preferred. As the inorganic particles, particles having an arbitrary shape such as a scale shape, a needle shape, or a dendritic shape can be used. The inorganic fine particles are preferably hollow and foamed fine particles in terms of dispersibility, stability and weight reduction when mixed with the polyimide precursor solution. The metal shell preferably covers 80% or more of the surface area of the core particle, more preferably 90% or more, and even more preferably 95% or more. The metal shell may be a single layer or a plurality of layers. In such a case, the core particle portion not covered with the metal shell may be covered with another metal. Examples of other conductive metals include noble metals such as platinum, gold and palladium, and base metals such as molybdenum, nickel, cobalt, iron, copper, zinc, tin, antimony, tungsten, manganese, titanium, vanadium and chromium. . In addition, it does not specifically limit as a method of forming a metal shell on a core particle, For example, electrolytic plating, electroless plating, vacuum evaporation, sputtering etc. are mentioned.

  The average particle size of the metal surface conductive fine particles is preferably in the range of 1 μm or more and less than 50 μm. When the average particle diameter of the metal surface conductive fine particles is within this range, the metal surface conductive fine particles are less likely to aggregate in the conductive particle-containing resin solution (described later), and the coating obtained from the conductive particle-containing resin solution is used. This is because the surface roughness of the film or film is lowered.

  In the present embodiment, the volume fraction of the metal surface conductive particles relative to the heat-resistant insulating material is preferably in the range of 20% by volume to 70% by volume, and in the range of 30% by volume to 60% by volume. More preferably, it is more preferably in the range of 35% to 55% by volume, and particularly preferably in the range of 40% to 50% by volume. Of course, the volume fraction needs to be changed depending on the target resistance value, but when the volume fraction is within this range, the balance between the mechanical characteristics and the heat generation characteristics of the heat generating resin layer 112 is excellent.

  In the present embodiment, when the shape of the metal surface conductive particles in the heat generating resin layer 112 is needle-shaped or the like, it is preferable that the metal surface conductive particles are oriented in the length direction. . This is because the electrical resistance value can be efficiently lowered with a relatively small amount of metal surface conductive particles, and uniform heat generation characteristics can be obtained.

(1-1-3) Mercapto group-containing nitrogen-containing aromatic heterocyclic compound In the present embodiment, the mercapto group-containing nitrogen-containing aromatic heterocyclic compound is a pyrimidine thiol compound represented by the following chemical formula (1), The triazine thiol compound represented by the chemical formula (2), an imidazole compound having at least one of a mercapto group and a substituted mercapto group, and a thiazole compound having at least one of a mercapto group and a substituted mercapto group are preferable. The mercapto group-containing nitrogen-containing aromatic heterocyclic compound functions not only as a metal scavenger but also as an imidizing agent in the present embodiment.

(In formula (1), at least one of R1, R2, R3 and R4 is an SH group or an SM group, and M is a metal or a substituted or unsubstituted ammonium.)

(In formula (2), at least one of R5, R6 and R7 is an SH group or an SM group, and M is a metal or a substituted or unsubstituted ammonium.)

  The pyrimidine thiol compound is not particularly limited, and is a compound having a pyrimidine skeleton and having at least one SH group (thiol group) or SM group (metal salt of thiol group or substituted or unsubstituted ammonium salt). I just need it. Further, the metal atom of the metal salt is not particularly limited, and examples thereof include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and copper. Specific examples of the pyrimidine thiol compound include 2-mercaptopyrimidine (2MP), 2-hydroxy-4-mercaptopyrimidine, 4-hydroxy-2-mercaptopyrimidine, and 2,4-diamino-6- Mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 4-amino-6-hydroxy-2-mercaptopyrimidine, 2-thiobarbituric acid, 4-hydroxy-2-mercapto-6-methylpyrimidine, 4,6 -Dimethyl-2-pyrimidine thiol (DMPT), 4,5-diamino-2,6-dimercaptopyrimidine, 4,5-diamino-6-hydroxy-2-mercaptopyrimidine and the salts thereof. In addition, these pyrimidine thiol compounds may be used independently and may be used together.

  The triazine thiol compound is not particularly limited, and is a compound having a triazine skeleton and having at least one SH group (thiol group) or SM group (metal salt of thiol group or substituted or unsubstituted ammonium salt). I just need it. The metal atom of the metal salt is not particularly limited, and examples thereof include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and copper. As the triazine thiol compound, specifically, for example, 2-amino-1,3,5-triazine-4,6-dithiol (ATDT), 2-di-n-butylamino-4,6- Examples include dimercapto-1,3,5-triazine (DBDMT), 2-phenylamino-4,6-dimercapto-1,3,5-triazine, trithiocyanuric acid (TTCA), and salts thereof. Of these triazine thiol compounds, trithiocyanuric acid monosodium salt and trithiocyanuric acid trisodium salt (TTCA-3Na) are particularly suitable. In addition, these triazine thiol compounds may be used independently and may be used together.

  The imidazole compound having at least one of a mercapto group and a substituted mercapto group is not particularly limited, has an imidazole skeleton, and has at least one SH group (thiol group) or SM group (metal salt of thiol group or substituted or Any compound having an unsubstituted ammonium salt) may be used. The metal atom of the metal salt is not particularly limited, and examples thereof include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and copper. Specific examples of the imidazole compound include 2-mercaptobenzimidazole (MBI), 2-mercaptoimidazole, 2-mercapto-1-methylimidazole, 2-mercapto-5-methylimidazole, and 5-amino. 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole (MMI), 2-mercapto-5-nitrobenzimidazole, 2-mercapto-5-methoxybenzimidazole, 2-mercaptobenzimidazole-5-carboxylic acid And their salts. In addition, these imidazole compounds may be used independently and may be used together.

  The thiazole compound having at least one of a mercapto group and a substituted mercapto group is not particularly limited, has a thiazole skeleton, and has at least one SH group (thiol group) or SM group (metal salt of thiol group or substituted or Any compound having an unsubstituted ammonium salt) may be used. The metal atom of the metal salt is not particularly limited, and examples thereof include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and copper. Specific examples of the imidazole compound include 2-benzothiazole thiol (BTT), 6-amino-2-mercaptobenzothiazole, 2-mercaptothiazole, and salts thereof. In addition, a thiazole compound may be used independently and may be used together.

(1-1-4) Boron-containing compound In the present embodiment, the boron-containing compound is not particularly limited, and is, for example, boron oxide.

(1-1-5) Polyacid-derived compound In the present embodiment, the polyacid-derived compound includes molybdenum (Mo), vanadium (V), tungsten (W), titanium (Ti), aluminum (Al), and niobium ( A compound containing at least one element of Nb), which may be a polyacid itself or a polyacid salt itself, a polyacid or a heated product of the polyacid salt, a polyacid or It may be a heat product of a polyacid salt and another compound. The metal atom in the case where the polyacid salt is a metal salt is not particularly limited, and examples thereof include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and copper. Is done.

  Examples of polyacids that produce such polyacid-derived compounds include phosphovanadic acid, germanovanadate, arsenic vanadic acid, phosphoniobic acid, germanoniobic acid, silicomolybdic acid (siliconomolybdic acid), phosphomolybdic acid, titanium Molybdic acid, germanomolybdic acid, arsenic molybdic acid, tin molybdic acid, phosphotungstic acid, germanotungstic acid, tin tungstic acid, silicotungstic acid, phosphomolybdovanadic acid, phosphotungstovanadic acid, germanotungstovanadic acid , Phosphomolybdo-tungstovanadic acid, germano-molybdo-tungstovanadic acid, lymmolybdotungstic acid, lymmolybdniobic acid, lintoungstomolybdic acid, phosphovanadomolybdic acid and the like. Examples of the polyacid salt that generates such a polyacid-derived compound include ammonium phosphomolybdate, sodium phosphomolybdate, ammonium molybdate, and ammonium tungstate.

  In this embodiment, particularly preferred polyacids are silicotungstic acid, phosphotungstic acid, and phosphomolybdic acid. These polyacids may be used alone or in combination. That is, at least one polyacid of silicotungstic acid, phosphotungstic acid and phosphomolybdic acid may be used. In other words, the polyacid-derived compound particularly preferable in the present embodiment includes at least one of molybdenum (Mo) and tungsten (W).

  The thickness of the heat generating resin layer 112 is preferably 10 μm or more. If the thickness of the heat generating resin layer 112 satisfies this condition, even if a slight variation occurs in the thickness of the heat generating resin layer 112, the fluctuation range of the resistance value becomes extremely narrow enough to withstand practical use. This is because the amount of heat generated can be stabilized even in the case of production. In consideration of ease of manufacture and flexibility of the resistance heating seamless tubular article 100, the thickness is preferably 200 μm or less.

<Characteristics of the resistance exothermic seamless tubular article according to the second embodiment>
(1) Initial resistance value The initial resistance value of the resistance heating seamless tubular article 100 according to the second embodiment is the same as the initial resistance value of the resistance heating seamless tubular article 100 according to the first embodiment.

(2) Resistance value fluctuation rate The resistance value fluctuation rate of the resistance heating seamless tubular object 100 according to the second embodiment is the same as the resistance value fluctuation rate of the resistance heating seamless tubular object 100 according to the first embodiment. is there.

<An example of a method for producing a resistance exothermic seamless tubular article according to the second embodiment>
The resistance exothermic seamless tubular article 100 according to the present embodiment is mainly composed of a conductive particle-containing polyimide precursor solution preparation step, an exothermic resin layer forming step, an electrode forming step, a primer coating step, a release layer forming step, and a firing step. It is manufactured through a demolding process. However, this manufacturing method is only an example and does not limit the present invention. Hereafter, each said manufacturing process is explained in full detail.

(1) Conductive particle-containing polyimide precursor solution preparation step In the conductive particle-containing polyimide precursor solution preparation step, the above-described metal surface conductive particles and the above-described mercapto group are contained in the polyimide precursor solution prepared as follows. A nitrogen-containing aromatic heterocyclic compound and boric acid are added to obtain a conductive particle-containing polyimide precursor solution. In the present embodiment, the mercapto group-containing nitrogen-containing aromatic heterocyclic compound and boric acid function as a resistance value stabilizer that stabilizes the resistance value of the resistance exothermic seamless tubular body 100. Further, the conductive particle-containing polyimide precursor solution is added with the above-described polyacid, the above-mentioned carbon nanomaterial, the above-mentioned electrically insulating particles, the above-mentioned fibrous particles, and the above-mentioned viscosity mineral as optional components. Also good. In addition, the addition method of these particle | grains and compounds is not specifically limited, The method of adding these particle | grains and compounds during polyimide precursor solution preparation as well as the method of adding these particles and compounds directly to a polyimide precursor solution. It may be.

  In the second embodiment, the metal surface conductive particles are polyimide precursors such that the volume fraction with respect to the solid content of the conductive particle-containing polyimide precursor solution is in the range of 5% by volume to 70% by volume. It is preferably added to the body solution, more preferably added to the polyimide precursor solution so as to be in the range of 10% by volume to 60% by volume, and in the range of 15% by volume to 50% by volume. More preferably, it is added to the polyimide precursor solution, particularly preferably added to the polyimide precursor solution so as to be in the range of 20% by volume to 40% by volume. Of course, the volume fraction needs to be changed depending on the target resistance value, but when the volume fraction is within this range, the balance between the mechanical characteristics and the heat generation characteristics of the heat generating resin layer 112 is excellent.

  In the second embodiment, the mercapto group-containing nitrogen-containing aromatic heterocyclic compound has a volume fraction with respect to the solid content of the conductive particle-containing polyimide precursor solution in the range of 0.01% by volume to 10% by volume. It is preferably added to the polyimide precursor solution so as to be within, more preferably added to the polyimide precursor solution so as to be within the range of 0.1% by volume or more and 5% by volume or less, More preferably, it is added to the polyimide precursor solution so as to be in the range of not less than 3% by volume and not more than 3% by volume, and is added to the polyimide precursor solution so as to be in the range of not less than 0.5% by volume and not more than 2% by volume. It is particularly preferred that Of course, the volume fraction needs to be changed depending on the target resistance stability, but if the volume fraction is within this range, the balance between resistance stabilization efficiency and cost reduction is excellent. .

  In the second embodiment, boric acid is a polyimide precursor solution so that the volume fraction with respect to the solid content of the conductive particle-containing polyimide precursor solution is in the range of 0.01 volume% to 30 volume%. It is preferably added to the polyimide precursor solution so as to be in the range of 0.1 volume% or more and 20 volume% or less, and in the range of 0.2 volume% or more and 10 volume% or less. More preferably, it is added to the polyimide precursor solution so as to be within the range, and particularly preferably added to the polyimide precursor solution so as to be within the range of 1% by volume or more and 5% by volume or less. Of course, the volume fraction needs to be changed depending on the target resistance stability, but if the volume fraction is within this range, the balance between resistance stabilization efficiency and cost reduction is excellent. .

  In the second embodiment, the polyacid or polyacid salt has a volume fraction with respect to the solid content of the conductive particle-containing polyimide precursor solution in the range of 0.01% by volume to 20% by volume. It is preferably added to the polyimide precursor solution, more preferably added to the polyimide precursor solution so as to be in the range of 0.1% by volume or more and 10% by volume or less, and 0.2% by volume or more and 5% by volume. More preferably, it is added to the polyimide precursor solution so as to be in the range of volume% or less, and may be added to the polyimide precursor solution so as to be in the range of 0.5 volume% or more and 3 volume% or less. Particularly preferred. Of course, the volume fraction needs to be changed depending on the target resistance stability, but if the volume fraction is within this range, the balance between resistance stabilization efficiency and cost reduction is excellent. .

  In the second embodiment, the carbon nanomaterial is a polyimide precursor that has a volume fraction with respect to the solid content of the conductive particle-containing polyimide precursor solution in the range of 0.1% by volume to 50% by volume. It is preferably added to the body solution, more preferably added to the polyimide precursor solution so as to be in the range of 0.5 volume% or more and 40 volume% or less, and the range of 1 volume% or more and 30 volume% or less. More preferably, it is added to the polyimide precursor solution so as to be inside, and it is particularly preferable that it is added to the polyimide precursor solution so as to be in the range of 2% by volume or more and 25% by volume or less. Of course, the volume fraction needs to be changed depending on the target resistance value, but when the volume fraction is within this range, the balance between the mechanical characteristics and the heat generation characteristics of the heat generating resin layer 112 is excellent.

  The polyimide precursor solution is prepared as described in the first embodiment. However, in the second embodiment, it is preferable to use 4,4′-diaminodiphenyl ether as the diamine and to use pyromellitic dianhydride as the tetracarboxylic dianhydride, and to use paraphenylenediamine as the diamine and tetra It is particularly preferable to use 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as the carboxylic dianhydride. Polyimide resins obtained from these monomers are excellent in mechanical properties and tough, and do not soften or melt like thermoplastic resins even when the temperature of the resistance exothermic seamless tubular article 100 rises, and have excellent heat resistance It is because it has.

(2) Exothermic resin layer molding process In the exothermic resin layer molding process, as shown in FIG. 8, the conductive particle-containing polyimide precursor solution VS is applied to the outer peripheral surface of the cylindrical core body 610 using a ring-shaped die 620. After uniformly coating, the core body 610 with the coating film CV is heated. The heating temperature at this time is preferably such that the organic polar solvent evaporates but imidization does not proceed, for example, a temperature within the range of 200 ° C. or more and 250 ° C. or less. You may raise to 450 degreeC. In such a case, when conductive metal surface conductive particles, carbon nanotubes, carbon nanofibers, or the like are added to the conductive particle-containing polyimide precursor solution, they are approximately in the direction in which the ring-shaped die travels. They are aligned and oriented in one direction.

(3) Electrode forming step The electrode forming step is the same as the electrode forming step according to the first embodiment. When silver paste is used when “nickel particles” or “core-shell type conductive particles having nickel as a shell” are used as the metal surface conductive particles, the heat generating resin layer 112 and the electrode 120 are usually used. However, when a polyacid, especially phosphomolybdic acid is added to the conductive particle-containing polyimide precursor solution, this deterioration can be prevented. For this reason, it is preferable that polyacid is added to the conductive particle-containing polyimide precursor solution.

(4) Primer coating process, release layer molding process, firing process and demolding process The primer coating process, release layer molding process, firing process and demolding process are the primer coating process, release process according to the first embodiment. This is the same as the mold layer forming step, firing step, and demolding step.

<Features of Resistance Heating Seamless Tubular Material According to Second Embodiment>
(1)
The resistance exothermic seamless tubular article 100 according to the second embodiment has a resistance fluctuation rate within a range of ± 30% when 100 hours have passed at a temperature of 300 ° C. For this reason, this resistance exothermic seamless tubular object 100 has a sufficiently small resistance value variation with use. The resistance heat generating seamless tubular article 100 has a heat generating resin layer 112. In the heat generating resin layer 112, metal surface conductive particles are added to the heat resistant resin as conductive particles. For this reason, this resistance exothermic seamless tubular object 100 can make the resistance value small. Therefore, this resistance heat generation seamless tubular object 100 can be reduced in size while the resistance value fluctuation accompanying use is small.

(2)
In the resistance exothermic seamless tubular body 100 according to the second embodiment, the heat generating resin layer 112 has a thickness of 10 μm or more. For this reason, even if a slight variation occurs in the thickness of the heat generating resin layer 112, the fluctuation range of the resistance value becomes extremely narrow enough to withstand practical use. Heat generation can be stabilized

(3)
In the resistance exothermic seamless tubular article 100 according to the second embodiment, the volume fraction of the metal surface conductive particles with respect to the exothermic resin layer 112 is in the range of 20 volume% or more and 70 volume% or less. Good flexibility can be imparted to the resistance exothermic seamless tubular article 100.

<Modification>
Modifications (A) to (J) of the first embodiment can be applied to the second embodiment. In the modification (A), when the base layer is provided on the main body 110, the heat generating resin layer 112 may have a thickness of 10 μm or more.

<Examples and Comparative Examples>
Hereinafter, the planar resistance heating element according to the present embodiment will be described in more detail with reference to examples and comparative examples. The present invention is not limited by these examples and comparative examples.

(1) Preparation of carbon nanofiber-containing polyimide precursor solution A Polyamic acid solution (composition: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter abbreviated as “BPDA”) / paraphenylene Diamine (hereinafter abbreviated as “PPD”), solid content 17.0% by mass 331.25 g, N-methylpyrrolidone (hereinafter abbreviated as “NMP”) 156.66 g and carbon nanofiber (hereinafter “CNF”) The mixture was mixed with 32.09 g to prepare a CNF-containing polyimide precursor solution A. In addition, the addition amount of CNF is calculated so that CNF may occupy 28.51 volume% with respect to solid content of the CNF containing polyimide precursor solution A at this time (refer Table 1).

(2) Preparation of silver powder-containing polyimide precursor solution B Polyamic acid solution (composition PMDA / ODA, solid content 15.4% by mass) 164.64 g, silver powder 59.44 g, NMP 38.35 g and 2-di-n-butylamino 0.12 g of -4,6-dimercapto-1,3,5-triazine (hereinafter abbreviated as “DBDMT”) was mixed to obtain a silver powder-containing polyimide precursor solution B.

(3) Production of resistance exothermic seamless tubular body First, the CNF-containing polyimide precursor solution A was uniformly applied to the surface of a cylindrical mold whose surface was release-treated, and then the coating film was applied at 100 ° C. for 10 minutes, 150 A polyimide tubular product A having a thickness of 60 μm was obtained by heating sequentially at 20 ° C. for 20 minutes, 250 ° C. for 30 minutes, and 400 ° C. for 15 minutes.

  Next, after uniformly applying the silver powder-containing polyimide precursor solution B to the surfaces of both ends of the polyimide tubular product A at 25 mm, the coating film was 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, Heating was performed sequentially at 300 ° C. for 60 minutes and at 350 ° C. for 30 minutes to remove the solvent and imidization treatment to form electrodes having a thickness of 20 μm on both ends of the polyimide tubular product A.

  Next, a primer solution is applied to “the outer surface of the central portion of the polyimide tubular article A on which no electrode is formed” and “the outer surface of a portion 5 mm from the end on the side of the central portion of the electrode”. Heated at 0 ° C. for 10 minutes. And after uniformly apply | coating silicone rubber to a primer liquid application part, it heated at 150 degreeC for 30 minutes and 200 degreeC for 30 minutes in order, and vulcanized silicone rubber, and formed the 300-micrometer-thick elastic layer. .

  Subsequently, a primer solution was applied to the outer surface of the elastic layer, and the coating film was heated at 150 ° C. for 10 minutes. And after apply | coating a fluororesin dispersion liquid uniformly to a primer application part, the coating film was dried for 10 minutes at 60 degreeC, and also it baked for 10 minutes at 340 degreeC, and the 20-micrometer-thick release layer was formed. As a result, a resistance heating seamless tubular product having a thickness of 382 μm, an inner diameter of 18.00 mm, and a length of 390 mm was obtained. In addition, the distance between electrodes of this resistance exothermic seamless tubular product was 230 mm.

(4) Measurement of initial resistance value The initial resistance value between electrodes of the resistance heating seamless tubular material was measured by a four-terminal method using a digital multimeter Model 7562 (manufactured by Yokogawa Electric Corporation). The initial resistance value was 19.08Ω (see Table 1).

(5) Measurement of resistance value when exposed to 300 ° C. Three resistance exothermic seamless tubular materials were prepared. Each of these resistance exothermic seamless tubular materials was allowed to stand in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours, and then the resistance exothermic seamless tubular materials were cooled to room temperature. And the resistance value of the resistance exothermic seamless tubular thing was calculated | required similarly to the above-mentioned. The resistance value of the resistance exothermic seamless tube after exposure for 48 hours is 17.70Ω, the resistance value of the resistance exothermic seamless tube after exposure for 100 hours is 17.45Ω, and the resistance exothermic seamless tube after exposure for 125 hours The resistance value was 17.39Ω (see Table 1).

(6) Calculation of resistance value fluctuation rate The resistance value fluctuation rate is calculated by ((300 ° C. × resistance value after exposure for t time) − (initial resistance value)) / (initial resistance value) × 100. That is, the resistance fluctuation rate of the resistance exothermic seamless tubular article after 48 hours exposure is −7.23% (= (17.70Ω-19.08Ω) /19.08Ω×100), and the resistance after 100 hours exposure is The resistance value fluctuation rate of the exothermic seamless tubular material is −8.54% (= (17.45Ω−19.08Ω) /19.08Ω×100), and the resistance value fluctuation of the resistance exothermic seamless tubular material after 125 hours exposure. The rate was −8.86% (= (17.39Ω−19.08Ω) /19.08Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution C A polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass) 401.85 g, NMP 98.06 g and CNF 20.09 g were mixed to obtain a CNF-containing polyimide precursor solution. C was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 17.07 volume% with respect to solid content of the CNF containing polyimide precursor solution C at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF-containing polyimide precursor solution C was used instead of the CNF-containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 382 μm (including a base layer of 60 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 18.00 mm, a length of 390 mm, and an interelectrode distance of 230 mm. there were.

(3) Measurement of initial resistance value The initial resistance value of the resistance heating seamless tubular product was measured by the same method as in Example 1. The initial resistance value was 69.26Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 62.77Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 61.07Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 60.75Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −9.37% (= (62.77Ω−69.26Ω) /69.26Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 100 hours is −11.83% ( = (61.07Ω-69.26Ω) /69.26Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular product after exposure for 125 hours was -12.29% (= (60.75Ω-69. 26Ω) /69.26Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution D A polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) 269.20 g, NMP 208.16 g, and CNF 42.64 g were mixed to obtain a CNF-containing polyimide precursor solution. D was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 39.47 volume% with respect to solid content of the CNF containing polyimide precursor solution D at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF containing polyimide precursor solution A was used instead of the CNF containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 392 μm (including a base layer of 70 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 25.00 mm, a length of 390 mm, and a distance between electrodes of 340 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance heating seamless tubular article was measured by the same method as in Example 1, the initial resistance value was 5.06Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 4.74Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 4.09Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 3.85Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −6.32% (= (4.74Ω−5.06Ω) /5.06Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 100 hours is −19.17% ( = (4.09Ω−5.06Ω) /5.06Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 125 hours is −23.91% (= (3.85Ω−5. 06Ω) /5.06Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution E 45.70 g of a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass), NMP 55.86 g and CNF 11.44 g were mixed to obtain a CNF-containing polyimide precursor solution. E was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 9.43 volume% with respect to solid content of the CNF containing polyimide precursor solution E at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF containing polyimide precursor solution E was used instead of the CNF containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 392 μm (including a base layer of 70 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 25.00 mm, a length of 390 mm, and a distance between electrodes of 340 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance exothermic seamless tubular material was measured by the same method as in Example 1, the initial resistance value was 149.50Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 130.66Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 117.22Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 112.29Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −12.60% (= (130.66Ω−149.50Ω) /149.50Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 100 hours is −21.59% ( = (117.22Ω-149.50Ω) /149.50Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 125 hours is −24.89% (= (112.29Ω-149.149). 50Ω) /149.50Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution F A polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass) 388.51 g, NMP 109.14 g and CNF 22.35 g were mixed to obtain a CNF-containing polyimide precursor solution. F was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 19.15 volume% with respect to solid content of the CNF containing polyimide precursor solution F at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF containing polyimide precursor solution A was used instead of the CNF containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 522 μm (including a base layer of 200 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 15.00 mm, a length of 400 mm, and a distance between electrodes of 350 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance heating seamless tubular material was measured by the same method as in Example 1, the initial resistance value was 30.12Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 27.79Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 27.60Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 27.50Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −7.74% (= (27.79Ω−30.12Ω) /30.12Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tube after exposure for 100 hours is −8.37% ( = (27.60Ω-30.12Ω) /30.12Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 125 hours is −8.70% (= (27.50Ω-30.30). 12Ω) /30.12Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution G A polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass) 291.92 g, NMP 189.31 g and CNF 38.77 g were mixed to obtain a CNF-containing polyimide precursor solution. G was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 35.36 volume% with respect to solid content of the CNF containing polyimide precursor solution G at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF-containing polyimide precursor solution A was used instead of the CNF-containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 372 μm (including a base layer of 50 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 3.18 mm, a length of 300 mm, and an interelectrode distance of 250 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance heating seamless tubular product was measured in the same manner as in Example 1, the initial resistance value was 65.04Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 59.06Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 57.65Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 57.43Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −9.19% (= (59.06Ω−65.04Ω) /65.04Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular article after 100 hours exposure is −11.36% ( = (57.65Ω−65.04Ω) /65.04Ω×100), and the resistance value fluctuation rate of the resistance exothermic seamless tubular material after exposure for 125 hours is −11.70% (= (57.43Ω−65.65). 04Ω) /65.04Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution H A polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) 368.40 g, NMP 125.83 g and CNF 25.77 g were mixed to obtain a CNF-containing polyimide precursor solution. H was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 22.36 volume% with respect to solid content of the CNF containing polyimide precursor solution H at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF containing polyimide precursor solution A was used instead of the CNF containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 397 μm (including a base layer of 75 μm, an elastic layer of 300 μm, a release layer of 20 μm), a circumference of 150 mm, a length of 350 mm, and an interelectrode distance of 300 mm. It was.

(3) Sheet-like resistance heating element The above-described resistance heating seamless tubular material was cut along the longitudinal direction to obtain a sheet-like resistance heating element having a length of 350 mm and a width of 150 mm.

(4) Measurement of initial resistance value When the initial resistance value of the sheet-like resistance heating element was measured by the same method as in Example 1, the initial resistance value was 15.03Ω (see Table 1).

(5) Measurement of resistance value after exposure at 300 ° C. After the sheet-like resistance heating element was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours as in Example 1, the same method as in Example 1 was used. When the resistance value of the sheet resistance heating element was measured, the resistance value of the sheet resistance heating element after exposure for 48 hours was 13.97Ω, and the resistance value of the sheet resistance heating element after exposure for 100 hours was 13.64Ω. The resistance value of the sheet resistance heating element after exposure for 125 hours was 13.52Ω (see Table 1).

(6) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each sheet-like resistance heating element described above was determined by the same calculation method as in Example 1, the resistance value fluctuation of the sheet-like resistance heating element after 48 hours exposure was obtained. The rate is −7.05% (= (13.97Ω-15.03Ω) /15.03Ω×100), and the resistance value fluctuation rate of the sheet resistance heating element after 100 hours exposure is −9.25% ( = (13.64Ω-15.03Ω) /15.03Ω×100), and the resistance fluctuation rate of the sheet-like resistance heating element after exposure for 125 hours is −10.05% (= (13.52Ω-15.Ω). 03Ω) /15.03Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution I 151.15 g of a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass), NMP 306.15 g and CNF 62.70 g were mixed to obtain a CNF-containing polyimide precursor solution. I was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 63.08 volume% with respect to solid content of the CNF containing polyimide precursor solution I at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF-containing polyimide precursor solution I was used instead of the CNF-containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 342 μm (including a base layer of 20 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 3.18 mm, a length of 400 mm, and an interelectrode distance of 350 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance heating seamless tubular product was measured by the same method as in Example 1, the initial resistance value was 10.02Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 9.35Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 8.87Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 8.65Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −6.69% (= (9.35Ω−10.02Ω) /10.02Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 100 hours is −11.48% ( = (8.87Ω-10.02Ω) /10.02Ω×100), and the resistance value fluctuation rate of the resistance exothermic seamless tubular product after exposure for 125 hours is −13.67% (= (8.65Ω−10. 02Ω) /10.02Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution J A polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass) 481.30 g, NMP 32.12 g and CNF 6.58 g were mixed to obtain a CNF-containing polyimide precursor solution. J was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 5.33 volume% with respect to solid content of the CNF containing polyimide precursor solution J at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF-containing polyimide precursor solution J was used instead of the CNF-containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 367 μm (including a base layer of 45 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 79.62 mm, a length of 270 mm, and an interelectrode distance of 220 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance heating seamless tubular product was measured in the same manner as in Example 1, the initial resistance value was 75.05Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 67.84Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 65.68Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 65.20Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −9.61% (= (67.84Ω−75.05Ω) /75.05Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tube after exposure for 100 hours is −12.49% ( = (65.68Ω−75.05Ω) /75.05Ω×100), and the resistance value fluctuation rate of the resistance exothermic seamless tubular material after exposure for 125 hours is −13.12% (= (65.20Ω−75.75). 05Ω) /75.05Ω×100) (see Table 1).

(1) Preparation of CNF-containing polyimide precursor solution K Polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass) 322.30 g, NMP164.09 g and CNF 33.61 g were mixed to obtain a CNF-containing polyimide precursor solution. K was prepared. In addition, the addition amount of CNF is calculated so that CNF may occupy 30.04 volume% with respect to solid content of the CNF containing polyimide precursor solution K at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the CNF-containing polyimide precursor solution K was used instead of the CNF-containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 422 μm (including a base layer of 100 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 14.65 mm, a length of 400 mm, and a distance between electrodes of 350 mm. there were.

(3) Measurement of initial resistance value When the initial resistance value of the resistance heating seamless tubular product was measured by the same method as in Example 1, the initial resistance value was 18.01Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours, 100 hours, and 125 hours in the same manner as in Example 1, the same method as in Example 1 was used. When the resistance value of the resistance exothermic seamless tubular material was measured, the resistance value of the resistance exothermic seamless tubular material after exposure for 48 hours was 16.71Ω, and the resistance value of the resistance exothermic seamless tubular material after exposure for 100 hours was 16.44Ω. The resistance value of the resistance exothermic seamless tubular product after exposure for 125 hours was 16.37Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate of each of the resistance exothermic seamless tubular objects described above was obtained by the same calculation method as in Example 1, the resistance value fluctuation of the resistance exothermic seamless tubular object after 48 hours exposure was obtained. The rate is −7.22% (= (16.71Ω−18.01Ω) /18.01Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 100 hours is −8.72% ( = (16.44Ω-18.01Ω) /18.01Ω×100), and the resistance fluctuation rate of the resistance exothermic seamless tubular material after exposure for 125 hours is −9.11% (= (16.37Ω-18. 01Ω) /18.01Ω×100) (see Table 1).

(Comparative Example 1)
(1) Preparation of CNF nickel powder-containing polyimide precursor solution L A mixture of polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) 195.01 g, NMP 260.23 g, CNF 12.80 g and nickel powder 40.00 g Thus, a CNF nickel powder polyimide precursor solution L was prepared. At this time, the amount of CNF and nickel powder added so that CNF occupies 13.00% by volume and nickel powder occupies 18.40% by volume with respect to the solid content of the CNF nickel powder polyimide precursor solution L. Is calculated (see Table 1).

(2) Production of Resistance Exothermic Seamless Tubular Material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that CNF nickel powder containing polyimide precursor solution L was used instead of CNF containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 392 μm (including a base layer of 70 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 30.01 mm, a length of 390 mm, and an interelectrode distance of 340 mm. Met.

(3) Measurement of initial resistance value When the initial resistance value of the resistance exothermic seamless tubular material was measured by the same method as in Example 1, the initial resistance value was 34.00Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours in the same manner as in Example 1, the resistance exothermic seamless tubular product was subjected to the same method as in Example 1. As a result, the resistance value was 66.60Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate was determined by the same calculation method as in Example 1, the resistance value fluctuation rate of this resistance heating seamless tubular product was + 95.88% (= (66.60Ω- 34.00Ω) /34.00Ω×100) (see Table 1).

(Comparative Example 2)
(1) Preparation of graphite powder-containing polyimide precursor solution M Polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) 328.00 g, NMP 150.65 g and graphite powder 29.96 g were mixed to contain graphite powder. A polyimide precursor solution M was prepared. In addition, the addition amount of graphite powder is calculated so that graphite powder may occupy 25.00 volume% with respect to solid content of the graphite powder containing polyimide precursor solution M at this time (refer Table 1).

(2) Production of resistance exothermic seamless tubular material A resistance exothermic seamless tubular product was produced in the same manner as in Example 1 except that the graphite powder-containing polyimide precursor solution M was used instead of the CNF-containing polyimide precursor solution A. The resistance heating seamless tubular product has a thickness of 392 μm (including a base layer of 70 μm, an elastic layer of 300 μm, a release layer of 20 μm), an inner diameter of 30.01 mm, a length of 390 mm, and an interelectrode distance of 340 mm. Met.

(3) Measurement of initial resistance value When the initial resistance value of the resistance exothermic seamless tubular material was measured in the same manner as in Example 1, the initial resistance value was 1208.56Ω (see Table 1).

(4) Measurement of resistance value after exposure to 300 ° C. After the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 48 hours in the same manner as in Example 1, the resistance exothermic seamless tubular product was subjected to the same method as in Example 1. As a result, the resistance value was 837.05Ω (see Table 1).

(5) Calculation of resistance value fluctuation rate When the resistance value fluctuation rate was determined by the same calculation method as in Example 1, the resistance value fluctuation rate of this resistance heating seamless tubular product was -30.74% (= (837.05Ω). −1208.56Ω) /1208.56Ω×100) (see Table 1).

(1) Preparation of Conductive Fine Particle-Containing Polyimide Precursor Solution N Polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) 35 g, N-methylpyrrolidone (hereinafter abbreviated as “NMP”) 1.70 g In addition, 16.57 g of filamentous nickel fine particles (TYPE 525 manufactured by NOVAMET), 0.0510 g of trithiocyanuric acid (hereinafter abbreviated as “TTCA”) (manufactured by Wako Pure Chemical Industries) and 0.1980 g of boric acid (manufactured by Nacalai Tesque) are mixed, Fine particle-containing polyimide precursor solution N was prepared. At this time, with respect to the solid content of the conductive fine particle-containing polyimide precursor solution N, filamentous nickel fine particles occupy 30.0% by volume, TTCA occupies 0.5% by volume, and boric acid 1.0% by volume. %, The addition amount of filamentary nickel fine particles, TTCA and boric acid is calculated (see Table 2).

(2) Preparation of silver powder-containing polyimide precursor solution O Polyamic acid solution (composition PMDA / ODA, solid content 15.4% by mass) 150 g, silver powder (AgC-A, manufactured by Fukuda Metal Foil Powder Industry, average particle size 3.1 μm) , Density 14 g / cm ³ ) 26.57 g, NMP 37.5 g and 2-di-n-butylamino-4,6-dimercapto-1,3,5-triazine (hereinafter abbreviated as “DBDMT”) 0.018 g Were mixed to prepare a silver powder-containing polyimide precursor solution O.

(3) Preparation of resistance exothermic seamless tubular material First, a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) was uniformly applied to the surface of a cylindrical mold whose surface was release-treated, The coating film was heated at 100 ° C. for 10 minutes and at 120 ° C. for 20 minutes to obtain a tubular base layer having a thickness of 50 μm.

  Next, after uniformly applying the conductive fine particle-containing polyimide precursor solution N to the surface of the base layer, the coating film is 100 ° C. for 10 minutes, 150 ° C. for 20 minutes, 250 ° C. for 30 minutes, and 400 ° C. for 15 minutes. The polyimide tubular product B was produced by sequentially heating under the conditions of the above, removing the solvent and imidizing. When this polyimide tubular product B was extracted from the cylindrical mold and the thickness, inner diameter and length were measured, the thickness was 70 μm, the inner diameter was 18 mm, and the length was 265 mm.

  Next, after uniformly applying the silver powder-containing polyimide precursor solution O to the surfaces of 25 mm on both ends of the polyimide tubular body B, the coating film is 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, Heating was performed sequentially at 300 ° C. for 60 minutes and at 350 ° C. for 30 minutes to perform solvent removal and imidization treatment to form electrodes having a thickness of 20 μm on both ends of the polyimide tubular product B.

  Next, a polyamic acid solution (composition BPDA / PPD, solid content) is added to “the outer surface of the central portion of the polyimide tubular body B on which no electrode is formed” and “the outer surface of the portion 5 mm from the end on the side of the central portion of the electrode”. 17.0% by mass), and the coating was applied in order under the conditions of 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, 300 ° C. for 60 minutes, and 350 ° C. for 30 minutes. The insulating layer was formed by heating to remove the solvent and imidization treatment. As a result, a resistance exothermic seamless tubular product having a thickness of 120 μm, an inner diameter of 18 mm, and a length of 265 mm was obtained. In addition, the distance between electrodes of this resistance heat generation seamless tubular thing was 215 mm.

(4) Measurement of initial resistance value The initial resistance value between electrodes of the resistance heating seamless tubular material was measured by a four-terminal method using a digital multimeter Model 7562 (manufactured by Yokogawa Electric Corporation). The initial resistance value was 17.6Ω (see Table 2).

(5) Measurement of resistance value after exposure at 300 ° C. for 100 hours The resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours, and then the resistance exothermic seamless tubular material was cooled to room temperature. And the resistance value of the resistance exothermic seamless tubular thing was calculated | required similarly to the above-mentioned. Its resistance value was 17.5Ω (see Table 2).

(6) Calculation of resistance value fluctuation rate The resistance value fluctuation rate is calculated by ((300 ° C. × resistance value after 100 hours exposure) − (initial resistance value)) / (initial resistance value) × 100. That is, the resistance value variation rate of this resistance exothermic seamless tubular product was −0.6% (= (17.5Ω−17.6Ω) /17.6Ω×100) (see Table 2).

(7) Observation of electrode deterioration The electrode was observed after exposing this resistance heating seamless tubular material at a temperature of 300 ° C. for 100 hours, but the electrode was firmly adhered, and the electrode was not peeled or deteriorated such as blister. It was not seen (see Table 2).

  A resistance exothermic seamless tubular product was prepared in the same manner as in Example 11 except that 0.0510 g of TTCA was replaced with 0.0440 g of 2-mercaptobenzimidazole (hereinafter abbreviated as “MBI”). The resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In the present example, the filamentous nickel fine particles occupy 30.0% by volume, MBI occupies 0.5% by volume, and boric acid is 1.% of the solid content of the conductive fine particle-containing polyimide precursor solution N. The addition amount of filamentary nickel fine particles, MBI and boric acid is calculated so as to occupy 0% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 21.3Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 17.5Ω (see Table 2). When the resistance value fluctuation rate was calculated, the value was −17.9% (= (17.5Ω-21.3Ω) /21.3Ω×100) (see Table 2). Moreover, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 2).

  A resistance exothermic seamless tubular material was prepared and carried out in the same manner as in Example 11 except that 0.0510 g of TTCA was replaced with 0.0370 g of 4,6-dimethyl-2-pyrimidinethiol (hereinafter abbreviated as “DMP”). In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, the DMP occupies 0.5% by volume, and the boric acid is 1.% with respect to the solid content of the conductive fine particle-containing polyimide precursor solution N. The amount of filamentary nickel fine particles, DMP and boric acid added is calculated so as to occupy 0% by volume (see Table 2).

  The initial resistance value of the resistance heating seamless tubular product was 14.5Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 12.2Ω (see Table 2). When the resistance value fluctuation rate was calculated, the value was −15.9% (= (12.2Ω-14.5Ω) /14.5Ω×100) (see Table 2). Moreover, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 2).

  Resistive heating as in Example 11 except that 0.0510 g of TTCA was replaced with 0.0380 g of 6-dibutylamino-1,3,5-triazine-2,4-dithiol (hereinafter abbreviated as “DBTDT”). A seamless tubular product was prepared, and the resistance characteristics of the resistance-heat generating seamless tubular product were measured in the same manner as in Example 11 and the deterioration of the electrode was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, DBTDT occupies 0.5% by volume, and boric acid is 1.% of the solid content of the conductive fine particle-containing polyimide precursor solution N. The addition amount of filamentary nickel fine particles, DBTDT and boric acid is calculated so as to occupy 0% by volume (see Table 2).

  The initial resistance value of this resistance exothermic seamless tubular product was 13.9Ω (see Table 2). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 13.2Ω (see Table 2). When the resistance value fluctuation rate was calculated, the value was −4.7% (= (13.2Ω−13.9Ω) /13.9Ω×100) (see Table 2). Moreover, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 2).

  A resistance exothermic seamless tubular material was produced in the same manner as in Example 11 except that 0.0510 g of TTCA was replaced with 0.0440 g of 2-benzothiazole thiol (hereinafter abbreviated as “BTT”). The resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, the BTT accounts for 0.5% by volume, and the boric acid is 1.% with respect to the solid content of the conductive fine particle-containing polyimide precursor solution N. The amount of filamentary nickel fine particles, BTT and boric acid added is calculated so as to occupy 0% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 15.8Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 15.1Ω (see Table 2). When the resistance value fluctuation rate was calculated, the value was −4.5% (= (15.1Ω-15.8Ω) /15.8Ω×100) (see Table 2). Moreover, in this resistance heating seamless tubular product, blisters were observed in the insulating layer polyimide covering the electrode part, and electrode peeling was observed, and electrode deterioration was observed (see Table 2).

  A resistance exothermic seamless tubular product was prepared in the same manner as in Example 11 except that 0.0510 g of TTCA was replaced with 0.0410 g of 2-mercapto-5-methylbenzimidazole (hereinafter abbreviated as “MMI”). In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, the MMI occupies 0.5% by volume, and the boric acid is 1.% with respect to the solid content of the conductive fine particle-containing polyimide precursor solution N. The addition amounts of filamentary nickel fine particles, MMI and boric acid are calculated so as to occupy 0% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 19.6Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 14.3Ω (see Table 2). When the resistance value fluctuation rate was calculated, the value was −27.1% (= (14.3Ω−19.6Ω) /19.6Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

(1) Preparation of conductive fine particle-containing polyimide precursor solution P 45 g of polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass), NMP 6.71 g, 26.53 g of filamentous nickel fine particles (TYPE525 made by NOVAMET), 2.981 g of carbon nanofiber (Showa Denko VGCF-H), 15% by weight trithiocyanuric acid trisodium salt aqueous solution (hereinafter abbreviated as “TTCA-3Na”) (Fluka) 2.41 g and boric acid (Nacalai Tesque) (Manufactured) 3.594 g was mixed to prepare a polyimide precursor solution P containing conductive fine particles. At this time, the filamentous nickel fine particles occupy 26.4% by volume, the carbon nanofibers occupy 13.2% by volume, and TTCA-3Na is based on the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of filamentary nickel fine particles, carbon nanofibers, TTCA-3Na and boric acid are calculated so as to occupy 2.0% by volume and boric acid occupy 10.0% by volume (see Table 2).

(2) Preparation of silver powder-containing polyimide precursor solution O A silver powder-containing polyimide precursor solution O was prepared in the same manner as in Example 11.

(3) Preparation of resistance exothermic seamless tubular material First, a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) was uniformly applied to the surface of a cylindrical mold whose surface was release-treated, The coating film was heated at 100 ° C. for 10 minutes and at 120 ° C. for 20 minutes to obtain a tubular base layer having a thickness of 50 μm.

  Next, after uniformly applying the conductive fine particle-containing polyimide precursor solution P to the surface of the base layer, the coating film is 100 ° C. for 10 minutes, 150 ° C. for 20 minutes, 250 ° C. for 30 minutes, and 400 ° C. for 15 minutes. The polyimide tubular product C was produced by sequentially heating under the above conditions, removing the solvent and imidizing. When this polyimide tubular product C was extracted from the cylindrical mold and the thickness, inner diameter and length were measured, the thickness was 70 μm, the inner diameter was 18 mm, and the length was 265 mm.

  Next, after uniformly applying the silver powder-containing polyimide precursor solution O to the surfaces of both ends 25 mm of the polyimide tubular product C, the coating film is 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, Heating was performed sequentially at 300 ° C. for 60 minutes and at 350 ° C. for 30 minutes to remove the solvent and imidization treatment to form electrodes having a thickness of 20 μm on both ends of the polyimide tubular product C.

  Next, the polyamic acid solution (composition BPDA / PPD, solid content) was added to “the outer surface of the central portion of the polyimide tubular article C on which no electrode was formed” and “the outer surface of the portion 5 mm from the end on the side of the central portion of the electrode”. 17.0% by mass), and the coating was applied in order under the conditions of 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, 300 ° C. for 60 minutes, and 350 ° C. for 30 minutes. The insulating layer was formed by heating to remove the solvent and imidization treatment. As a result, a resistance exothermic seamless tubular product having a thickness of 120 μm, an inner diameter of 18 mm, and a length of 265 mm was obtained. In addition, the distance between electrodes of this resistance heat generation seamless tubular thing was 215 mm.

(4) Measurement of initial resistance value When the initial resistance value of the resistance exothermic seamless tubular material was measured in the same manner as in Example 11, the initial resistance value was 41.7Ω (see Table 2).

(5) Measurement of resistance value after exposure to 300 ° C. × 100 hours In the same manner as in Example 11, when the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was measured, the resistance value was measured. Was 46.0Ω (see Table 2).

(6) Calculation of resistance value fluctuation rate In the same manner as in Example 11, when the resistance value fluctuation rate of this resistance heating seamless tubular product was calculated, the value was + 10.2% (= (46.0Ω-41.7Ω). ) /41.7Ω×100) (see Table 2).

(7) Observation of electrode deterioration When electrode deterioration was observed in the same manner as in Example 11, electrode deterioration was observed in this resistance heating seamless tubular material (see Table 2).

  Resistive exothermic seamless tubular material as in Example 17 except that the amount of NMP added was changed to 6.30 g, the amount of TTCA-3Na added was changed to 0.550 g, and the amount of boric acid added was changed to 0.8152 g. In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 29.1% by volume and the carbon nanofibers occupy 14.6% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of filamentary nickel fine particles, carbon nanofibers, TTCA-3Na and boric acid are calculated so that 3Na occupies 0.5% by volume and boric acid occupies 2.5% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 34.9Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 37.0Ω (see Table 2). When the resistance value fluctuation rate was calculated, it was + 5.9% (= (37.0Ω−34.9Ω) /34.9Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

  The addition amount of filamentary nickel fine particles was changed to 22.11 g, the addition amount of carbon nanofibers was changed to 3.974 g, 2.41 g of TTCA-3Na was changed to 0.0849 g of TTCA, and the addition amount of boric acid was changed to 0.8152 g. Except for the above, a resistance exothermic seamless tubular product was produced in the same manner as in Example 17, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 24.3 volume%, the carbon nanofibers occupy 19.4 volume%, and the TTCA is based on the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of filamentary nickel fine particles, carbon nanofibers, TTCA and boric acid are calculated so as to occupy 0.5% by volume and boric acid occupies 2.5% by volume (see Table 2).

  The initial resistance value of this resistance exothermic seamless tubular product was 62.0Ω (see Table 2). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 67.2Ω (see Table 2). When the resistance value fluctuation rate was calculated, the value was + 8.4% (= (67.2Ω-62.0Ω) /62.0Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

  The addition amount of filamentary nickel fine particles was changed to 30.95 g, the addition amount of carbon nanofibers was changed to 1.987 g, 2.41 g of TTCA-3Na was changed to 0.0849 g of TTCA, and the addition amount of boric acid was changed to 0.8152 g. Except for the above, a resistance exothermic seamless tubular product was produced in the same manner as in Example 17, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and electrode deterioration was observed. In this example, the filamentous nickel fine particles account for 34.0% by volume, the carbon nanofibers account for 9.7% by volume, and the TTCA is based on the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of filamentary nickel fine particles, carbon nanofibers, TTCA and boric acid are calculated so as to occupy 0.5% by volume and boric acid occupies 2.5% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 17.1Ω (see Table 2). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 17.2Ω (see Table 2). When the resistance value fluctuation rate was calculated, it was + 0.7% (= (17.2Ω-17.1Ω) /17.1Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

  A resistance exothermic seamless tubular material was prepared in the same manner as in Example 17 except that the filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with scaly nickel fine particles (NOCAMET HCA-1). The resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the flaky nickel fine particles occupy 26.4% by volume, the carbon nanofibers occupy 13.2% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of the scaly nickel fine particles, carbon nanofibers, TTCA-3Na and boric acid are calculated so that 3Na occupies 2.0% by volume and boric acid occupies 10.0% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 24.2Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 26.2Ω (see Table 2). When the resistance value fluctuation rate was calculated, it was + 8.3% (= (26.2Ω−24.2Ω) /24.2Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

  The amount of NMP added was changed to 6.30 g, the filamentous nickel fine particles (TYPE 525 made by NOVAMET) were changed to scaly nickel fine particles (NOCAMET HCA-1), the amount of TTCA-3Na was changed to 0.550 g, A resistance exothermic seamless tubular product was prepared in the same manner as in Example 17 except that the amount added was changed to 0.8152 g, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and the electrode was deteriorated. Was observed. In this example, scale-like nickel fine particles account for 29.1% by volume, carbon nanofibers account for 14.6% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of scaly nickel fine particles, carbon nanofibers, TTCA-3Na and boric acid are calculated so that 3Na occupies 0.5% by volume and boric acid occupies 2.5% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 24.6Ω (see Table 2). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 26.7Ω (see Table 2). When the resistance value fluctuation rate was calculated, it was + 8.7% (= (26.7Ω−24.6Ω) /24.6Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

  The amount of NMP added was changed to 6.30 g, 26.53 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were changed to 22.11 g of scaly nickel fine particles (HCA-1 made by NOVAMET), and the amount of carbon nanofibers added was changed to 3.11 g. A resistance exothermic seamless tubular material was prepared in the same manner as in Example 17 except that 2.41 g of TTCA-3Na was replaced by 0.0894 g of TTCA and 904% of boric acid was replaced by 0.8152 g instead of 974 g. Similarly, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles account for 24.3% by volume, the carbon nanofibers account for 19.4% by volume, and the TTCA is based on the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of the scaly nickel fine particles, carbon nanofibers, TTCA and boric acid are calculated so as to occupy 0.5% by volume and boric acid occupies 2.5% by volume (see Table 2).

  The initial resistance value of the resistance exothermic seamless tubular product was 48.1Ω (see Table 2). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 54.9Ω (see Table 2). When the resistance value fluctuation rate was calculated, it was + 14.1% (= (54.9Ω-48.1Ω) /48.1Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

  The amount of NMP added was changed to 6.30 g, 26.53 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were changed to 30.95 g of flaky nickel fine particles (HCA-1 made by NOVAMET), and the amount of carbon nanofiber added was 1. Instead of 987 g, 2.41 g of TTCA-3Na was replaced by 0.0849 g of TTCA, and a resistance exothermic seamless tubular product was produced in the same manner as in Example 17 except that the amount of boric acid was changed to 0.8152 g. Similarly, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 34.0% by volume, the carbon nanofibers occupy 9.7% by volume, and the TTCA is based on the solid content of the conductive fine particle-containing polyimide precursor solution P. The addition amounts of the scaly nickel fine particles, carbon nanofibers, TTCA and boric acid are calculated so as to occupy 0.5% by volume and boric acid occupies 2.5% by volume (see Table 2).

  The initial resistance value of the resistance heating seamless tubular product was 13.5Ω (see Table 2). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 14.0Ω (see Table 2). When the resistance value fluctuation rate was calculated, it was + 3.7% (= (14.0Ω-13.5Ω) /13.5Ω×100) (see Table 2). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 2).

(1) Preparation of conductive fine particle-containing polyimide precursor solution Q 35 g of polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass), 2.18 g of NMP, 16.81 g of filamentous nickel fine particles (TYPE525 made by NOVAMET), 0.0520 g of TTCA, 0.2000 g of boric acid and 0.195 g of phosphomolybdic acid (hereinafter abbreviated as “PMoA”) (manufactured by Nacalai Tesque) were mixed to prepare a conductive fine particle-containing polyimide precursor solution Q. At this time, with respect to the solid content of the conductive fine particle-containing polyimide precursor solution Q, the filamentous nickel fine particles occupy 30.0% by volume, TTCA accounts for 0.5% by volume, and boric acid is 1.0% by volume. %, And the addition amount of filamentary nickel fine particles, TTCA, boric acid and PMoA is calculated so that PMoA accounts for 1.0% by volume (see Table 3).

(2) Preparation of silver powder-containing polyimide precursor solution O A silver powder-containing polyimide precursor solution O was prepared in the same manner as in Example 11.

(3) Preparation of resistance exothermic seamless tubular material First, a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) was uniformly applied to the surface of a cylindrical mold whose surface was release-treated, The coating film was heated at 100 ° C. for 10 minutes and at 120 ° C. for 20 minutes to obtain a tubular base layer having a thickness of 50 μm.

  Next, after uniformly applying the conductive fine particle-containing polyimide precursor solution Q to the surface of the base layer, the coating film is 100 ° C. for 10 minutes, 150 ° C. for 20 minutes, 250 ° C. for 30 minutes, and 400 ° C. for 15 minutes. The polyimide tubular product D was prepared by sequentially heating under the above conditions, removing the solvent and imidizing. When this polyimide tubular product D was extracted from the cylindrical mold and the thickness, inner diameter and length were measured, the thickness was 70 μm, the inner diameter was 18 mm, and the length was 265 mm.

  Next, after uniformly applying the silver powder-containing polyimide precursor solution O to the surfaces of both ends 25 mm of the polyimide tubular product D, the coating film is 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, Heating was performed sequentially at 300 ° C. for 60 minutes and at 350 ° C. for 30 minutes to remove the solvent and imidization treatment to form electrodes having a thickness of 20 μm on both ends of the polyimide tubular product D.

  Next, the polyamic acid solution (composition BPDA / PPD, solid content) was added to the “outer surface of the central portion of the polyimide tubular article D on which no electrode was formed” and “the outer surface of the portion 5 mm from the end on the side of the central portion of the electrode”. 17.0% by mass), and the coating was applied in order under the conditions of 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, 300 ° C. for 60 minutes, and 350 ° C. for 30 minutes. The insulating layer was formed by heating to remove the solvent and imidization treatment. As a result, a resistance exothermic seamless tubular product having a thickness of 120 μm, an inner diameter of 18 mm, and a length of 265 mm was obtained. In addition, the distance between electrodes of this resistance heat generation seamless tubular thing was 215 mm.

(4) Measurement of initial resistance value In the same manner as in Example 11, the initial resistance value of the resistance exothermic seamless tubular product was measured and found to be 21.3Ω (see Table 3).

(5) Measurement of resistance value after exposure to 300 ° C. × 100 hours In the same manner as in Example 11, when the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was measured, the resistance value was measured. Was 19.1Ω (see Table 3).

(6) Calculation of resistance value fluctuation rate In the same manner as in Example 11, when the resistance value fluctuation rate of the resistance heating seamless tubular product was calculated, the value was -10.3% (= (19.1Ω-21. 3Ω) /21.3Ω×100) (see Table 3).

(7) Observation of electrode deterioration When electrode deterioration was observed in the same manner as in Example 11, no electrode deterioration was observed in this resistance heating seamless tubular material (see Table 3).

  A resistance exothermic seamless tubular product was prepared in the same manner as in Example 25 except that PMoA was replaced with phosphotungstic acid (hereinafter abbreviated as “PWA”). The resistance characteristics of the electrode were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, the TTCA occupies 0.5% by volume, and the boric acid is 1.% of the solid content of the conductive fine particle-containing polyimide precursor solution Q. The addition amounts of the filamentous nickel fine particles, TTCA, boric acid and PWA are calculated so as to occupy 0% by volume and PWA account for 1.0% by volume (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 17.1Ω (see Table 3). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 17.9Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was + 4.8% (= (17.9Ω−17.1Ω) /17.1Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  A resistance exothermic seamless tubular product was prepared in the same manner as in Example 25 except that PMoA was replaced with silicotungstic acid (hereinafter abbreviated as “SiWA”). The resistance characteristics of the electrode were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, the TTCA occupies 0.5% by volume, and the boric acid is 1.% of the solid content of the conductive fine particle-containing polyimide precursor solution Q. The addition amounts of filamentary nickel fine particles, TTCA, boric acid and SiWA are calculated so that 0% by volume and SiWA account for 1.0% by volume (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 19.0Ω (see Table 3). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 19.5Ω (see Table 3). The resistance value fluctuation rate was calculated and found to be + 2.7% (= (19.5Ω-19.0Ω) /19.0Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  In the preparation of the conductive fine particle-containing polyimide precursor solution Q, the polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) is replaced with a polyamic acid solution (composition PMDA / ODA, solid content 15.4% by mass), Example 25 except that the addition amount of NMP was changed to 1.09 g, the addition amount of TTCA was changed to 0.0470 g, the addition amount of boric acid was changed to 0.1820 g, and the addition amount of PMoA was changed to 0.177 g. In the same manner as described above, a resistance exothermic seamless tubular product was produced. In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular product were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 30.0% by volume, the TTCA occupies 0.5% by volume, and the boric acid is 1.% of the solid content of the conductive fine particle-containing polyimide precursor solution Q. The addition amounts of filamentary nickel fine particles, TTCA, boric acid and PMoA are calculated so that 0% by volume and PMoA account for 1.0% by volume (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 17.9Ω (see Table 3). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 18.5Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 3.4% (= (18.5Ω−17.9Ω) /17.9Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

(1) Preparation of conductive fine particle-containing polyimide precursor solution R Polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass) 45 g, NMP 6.59 g, filamentous nickel fine particles (TYPE525 from NOVAMET) 26.53 g, Carbon nanofibers (VGCF-H manufactured by Showa Denko KK) 2.981 g, TTCA 0.549 g, boric acid 0.6560 g and PMoA 0.319 g were mixed to prepare a conductive fine particle-containing polyimide precursor solution R. At this time, with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R, filamentous nickel fine particles occupy 29.0% by volume, carbon nanofibers occupy 14.5% by volume, and TTCA-3Na The addition amount of filamentary nickel fine particles, TTCA-3Na, boric acid and PMoA is calculated so that 0.5 volume%, boric acid accounts for 2.0 volume%, and PMoA accounts for 1.0 volume%. (See Table 3).

(2) Preparation of silver powder-containing polyimide precursor solution O A silver powder-containing polyimide precursor solution O was prepared in the same manner as in Example 11.

(3) Preparation of resistance exothermic seamless tubular material First, a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) was uniformly applied to the surface of a cylindrical mold whose surface was release-treated, The coating film was heated at 100 ° C. for 10 minutes and at 120 ° C. for 20 minutes to obtain a tubular base layer having a thickness of 50 μm.

  Next, after uniformly applying the conductive fine particle-containing polyimide precursor solution R to the surface of the base layer, the coating film is 100 ° C. for 10 minutes, 150 ° C. for 20 minutes, 250 ° C. for 30 minutes, and 400 ° C. for 15 minutes. The polyimide tubular product E was produced by sequentially heating under the above conditions to remove the solvent and imidize. The polyimide tubular product E was extracted from the cylindrical mold and the thickness, inner diameter and length were measured. The thickness was 70 μm, the inner diameter was 18 mm, and the length was 265 mm.

  Next, after uniformly applying the silver powder-containing polyimide precursor solution O to the surfaces of both ends 25 mm of the polyimide tubular product E, the coating film is 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, Heating was performed sequentially at 300 ° C. for 60 minutes and at 350 ° C. for 30 minutes to perform solvent removal and imidization treatment to form electrodes having a thickness of 20 μm on both ends of the polyimide tubular product E.

  Next, the polyamic acid solution (composition BPDA / PPD, solid content) was added to the “outer surface of the central portion of the polyimide tubular body E on which no electrode was formed” and “the outer surface of the portion 5 mm from the end on the central portion side of the electrode”. 17.0% by mass), and the coating was applied in order under the conditions of 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, 300 ° C. for 60 minutes, and 350 ° C. for 30 minutes. The insulating layer was formed by heating to remove the solvent and imidization treatment. As a result, a resistance exothermic seamless tubular product having a thickness of 120 μm, an inner diameter of 18 mm, and a length of 265 mm was obtained. In addition, the distance between electrodes of this resistance heat generation seamless tubular thing was 215 mm.

(4) Measurement of initial resistance value In the same manner as in Example 11, the initial resistance value of the resistance exothermic seamless tubular product was measured, and the initial resistance value was 31.3Ω (see Table 3).

(5) Measurement of resistance value after exposure at 300 ° C. for 100 hours In the same manner as in Example 11, when the resistance value after the resistance exothermic seamless tubular product was left in a 300 ° C. environment for 100 hours was measured, the value was 29.5Ω (see Table 3).

(6) Calculation of resistance value fluctuation rate In the same manner as in Example 11, when the resistance value fluctuation rate of the resistance heating seamless tubular product was calculated, the value was −5.7% (= (29.5Ω−31. 3Ω) /31.3Ω×100) (see Table 3).

(7) Observation of electrode deterioration When electrode deterioration was observed in the same manner as in Example 11, no electrode deterioration was observed in this resistance heating seamless tubular material (see Table 3).

  Implementation was performed except that the amount of NMP added was changed to 7.45 g, the amount of TTCA-3Na added was changed to 1.14 g, the amount of boric acid added was changed to 1.700 g, and the amount of PMoA added was changed to 0.331 g. A resistance exothermic seamless tubular product was prepared in the same manner as in Example 29, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 27.9% by volume and the carbon nanofibers occupy 14.0% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of filamentary nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 51.1Ω (see Table 3). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 64.6Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was + 26.5% (= (64.6Ω−51.1Ω) /51.1Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  NMP added to 7.45 g, TTCA-3Na added to 1.14 g, boric acid added to 1.700 g, PMoA added to 0.331 g, resistance exothermic seamless A resistance exothermic seamless tubular product was produced in the same manner as in Example 29 except that the polyamic acid solution for forming the insulating layer was replaced with a polyamic acid solution (composition PMDA / ODA, solid content: 15.4% by mass) in the production of the tubular product. In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the filamentous nickel fine particles occupy 27.9% by volume and the carbon nanofibers occupy 14.0% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of filamentary nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 65.7Ω (see Table 3). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 65.7Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 0.0% (= (65.7Ω-65.7Ω) /65.7Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added is changed to 7.45 g, the amount of filamentary nickel fine particles added is changed to 19.90 g, the amount of carbon nanofiber added is changed to 4.471 g, and the amount of TTCA-3Na added is changed to 1.14 g. The addition amount of boric acid is changed to 1.700 g, the addition amount of PMoA is changed to 0.331 g, and the polyamic acid solution for forming an insulating layer is made into a polyamic acid solution (composition PMDA / ODA, A resistance exothermic seamless tubular product was prepared in the same manner as in Example 29 except that the solid content was changed to 15.4% by mass, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11. Electrode degradation was observed. In this example, the filamentous nickel fine particles occupy 20.9% by volume, the carbon nanofibers occupy 20.9% by volume of the solid content of the conductive fine particle-containing polyimide precursor solution R, TTCA- Addition of filamentary nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 202.9Ω (see Table 3). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 248.1Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 22.3% (= (248.1Ω−202.9Ω) /202.9Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added is changed to 7.45 g, the filamentous nickel fine particles (TYPE 525 made by NOVAMET) are changed to scale-like nickel fine particles (NOCAMET HCA-1), the amount of TTCA-3Na is changed to 1.14 g, A resistance exothermic seamless tubular material was prepared in the same manner as in Example 29 except that the addition amount was changed to 1.700 g and the addition amount of PMoA was changed to 0.331 g. The resistance characteristics of the tubular material were measured, and electrode deterioration was observed. In this example, the flaky nickel fine particles occupy 27.9% by volume, the carbon nanofibers occupy 14.0% by volume, and the TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 27.4Ω (see Table 3). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 28.9Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 5.5% (= (28.9Ω−27.4Ω) /27.4Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added is changed to 7.45 g, the filamentous nickel fine particles (TYPE 525 made by NOVAMET) are changed to scale-like nickel fine particles (NOCAMET HCA-1), the amount of TTCA-3Na is changed to 1.14 g, The addition amount was changed to 1.700 g, the addition amount of PMoA was changed to 0.331 g, and the obtained resistance exothermic seamless tubular material was annealed at 400 ° C. for 2 hours, as in Example 29. Then, a resistance exothermic seamless tubular product was prepared, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and the electrode deterioration was observed. In this example, the flaky nickel fine particles occupy 27.9% by volume, the carbon nanofibers occupy 14.0% by volume, and the TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 27.0Ω (see Table 3). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 27.4Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 1.5% (= (27.4Ω-27.0Ω) /27.0Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added is changed to 7.45 g, the filamentous nickel fine particles (TYPE 525 made by NOVAMET) are changed to scale-like nickel fine particles (NOCAMET HCA-1), the amount of TTCA-3Na is changed to 1.14 g, The addition amount is changed to 1.700 g, the addition amount of PMoA is changed to 0.331 g, and the polyamic acid solution for forming an insulating layer is made into a polyamic acid solution (composition PMDA / ODA, solids 15 .4 mass%) except that the resistance exothermic seamless tubular material was prepared in the same manner as in Example 29, and the resistance characteristics of the resistance exothermic seamless tubular material were measured in the same manner as in Example 11 and the electrode was deteriorated. Observed. In this example, the flaky nickel fine particles occupy 27.9% by volume, the carbon nanofibers occupy 14.0% by volume, and the TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 22.5Ω (see Table 3). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 21.4Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was −4.9% (= (21.4Ω−22.5Ω) /22.5Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added is changed to 7.45 g, the filamentous nickel fine particles (TYPE 525 made by NOVAMET) are changed to scale-like nickel fine particles (NOCAMET HCA-1), the amount of TTCA-3Na is changed to 1.14 g, The addition amount is changed to 1.700 g, the addition amount of PMoA is changed to 0.331 g, and the polyamic acid solution for forming an insulating layer is made into a polyamic acid solution (composition PMDA / ODA, solids 15 4 mass%), a resistance exothermic seamless tubular product was produced in the same manner as in Example 29 except that the obtained resistance exothermic seamless tubular product was annealed at 400 ° C. for 2 hours. Similarly, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the flaky nickel fine particles occupy 27.9% by volume, the carbon nanofibers occupy 14.0% by volume, and the TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 1.0% by volume, boric acid occupies 5.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 24.0Ω (see Table 3). In addition, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 22.5Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was −6.3% (= (22.5Ω−24.0Ω) /24.0Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  A resistance exothermic seamless tubular material was prepared in the same manner as in Example 29 except that the filamentary nickel fine particles (TYPE 525 made by NOVAMET) were replaced with scaly nickel fine particles (NOCAMET HCA-1). The resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of this resistance exothermic seamless tubular product was 22.9Ω (see Table 3). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 20.1Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was -12.4% (= (20.1Ω-22.9Ω) /22.9Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  Filamentous nickel fine particles (NOVAMET TYPE 525) are replaced with scaly nickel fine particles (NOVAMET HCA-1), and a polyamic acid solution (composition PMDA / ODA) for forming an insulating layer in the production of a resistance exothermic seamless tubular material is used. , Except that the solid content was changed to 15.4% by mass), a resistance exothermic seamless tubular product was prepared in the same manner as in Example 29, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11. In addition, electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 22.2Ω (see Table 3). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 18.6Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was -16.3% (= (18.6Ω-22.2Ω) /22.2Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added was changed to 9.96 g, 26.53 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were changed to 17.68 g of scaly nickel fine particles (HCA-1 made by NOVAMET), and the amount of carbon nanofibers added was changed to 4.68 g. A resistance exothermic seamless tubular product was produced in the same manner as in Example 29 except that the amount was changed to 968 g, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and electrode deterioration was observed. In this example, scale-like nickel fine particles occupy 19.3% by volume, carbon nanofibers occupy 24.1% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of this resistance exothermic seamless tubular product was 153.2Ω (see Table 3). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 172.2Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 12.4% (= (172.2Ω-153.2Ω) /153.2Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  The amount of NMP added was changed to 9.96 g, 26.53 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were changed to 17.68 g of scaly nickel fine particles (HCA-1 made by NOVAMET), and the amount of carbon nanofibers added was changed to 4.68 g. Instead of 968 g, the same procedure as in Example 29 was performed except that the polyamic acid solution for forming the insulating layer was replaced with a polyamic acid solution (composition PMDA / ODA, solid content: 15.4% by mass) in the production of the resistance exothermic seamless tubular product. Then, a resistance exothermic seamless tubular product was prepared, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and the deterioration of the electrode was observed. In this example, scale-like nickel fine particles occupy 19.3% by volume, carbon nanofibers occupy 24.1% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PMoA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume and PMoA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 141.3Ω (see Table 3). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 140.0Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was −0.9% (= (140.0Ω−141.3Ω) /141.3Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  26.53 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) are replaced with 36.47 g of scaly nickel fine particles (HCA-1 made by NOVAMET), NMP is added in an amount of 9.61 g, and carbon nanofibers are added in an amount of 4. In place of 098 g, the addition amount of TTCA-3Na is changed to 0.755 g, the addition amount of boric acid is changed to 0.9010 g, the addition amount of PMoA is changed to 0.439 g, and the conductive fine particle-containing polyimide precursor solution R A resistance exothermic seamless tubular material was produced in the same manner as in Example 29 except that 8.11 g of round alumina (AS-50, Showa Denko Co., Ltd.) was added. The resistance characteristics of the tubular material were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Scalar nickel fine particles, carbon nanofibers, so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume, PMoA occupies 1.0% by volume, and alumina occupies 14.5% by volume. , TTCA-3Na, boric acid, PMoA and alumina addition amounts have been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 15.3Ω (see Table 3). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 14.9Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was -2.4% (= (14.9Ω-15.3Ω) /15.3Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  A resistance exothermic seamless tubular material was prepared in the same manner as in Example 29 except that the filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with scaly nickel fine particles (HCA-1 made by NOVAMET) and PMoA was replaced by SiWA. In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and SiWA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume and SiWA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of this resistance exothermic seamless tubular product was 27.6Ω (see Table 3). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 30.2Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was + 9.4% (= (30.2Ω-27.6Ω) /27.6Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  Filamentous nickel fine particles (TYPE 525 made by NOVAMET) are replaced with scaly nickel fine particles (HCA-1 made by NOVAMET), PMoA is replaced by SiWA, and a polyamic acid solution for forming an insulating layer is produced in polyamic acid in the production of a resistance exothermic seamless tubular product. A resistance exothermic seamless tubular product was prepared in the same manner as in Example 29 except that the solution (composition PMDA / ODA, solid content 15.4% by mass) was used. The resistance characteristics of the electrode were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and SiWA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume and SiWA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 21.5Ω (see Table 3). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 22.4Ω (see Table 3). When the resistance value fluctuation rate was calculated, it was + 4.3% (= (22.4Ω-21.5Ω) /21.5Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  A resistance exothermic seamless tubular material was prepared in the same manner as in Example 29 except that the filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with scaly nickel fine particles (HCA-1 made by NOVAMET) and PMoA was replaced by PWA. In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PWA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume, and PWA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 20.7Ω (see Table 3). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 23.9Ω (see Table 3). The resistance value fluctuation rate was calculated and found to be + 15.5% (= (23.9Ω-20.7Ω) /20.7Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

  Filamentary nickel fine particles (NOVAMET TYPE 525) are replaced with scaly nickel fine particles (NOVAMET HCA-1), PMoA is replaced with PWA, and a polyamic acid solution for forming an insulating layer in the production of a resistance exothermic seamless tubular material is polyamic acid. A resistance exothermic seamless tubular product was prepared in the same manner as in Example 29 except that the solution (composition PMDA / ODA, solid content 15.4% by mass) was used. The resistance characteristics of the electrode were measured, and electrode deterioration was observed. In this example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 14.5% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution R. Addition of flaky nickel fine particles, carbon nanofibers, TTCA-3Na, boric acid and PWA so that 3Na occupies 0.5% by volume, boric acid occupies 2.0% by volume, and PWA occupies 1.0% by volume The quantity has been calculated (see Table 3).

  The initial resistance value of the resistance exothermic seamless tubular product was 21.5Ω (see Table 3). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 20.4Ω (see Table 3). When the resistance value fluctuation rate was calculated, the value was −5.1% (= (20.4Ω−21.5Ω) /21.5Ω×100) (see Table 3). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 3).

(Comparative Example 3)
(1) Preparation of Conductive Fine Particle-Containing Polyimide Precursor Solution S 45 g of polyamic acid solution (composition BPDA / PPD, solid content: 17.0% by mass), 1.40 g of NMP, and 20.84 g of filamentous nickel fine particles (TYPE 525 manufactured by NOVAMET) The mixture was mixed to prepare a conductive fine particle-containing polyimide precursor solution S. At this time, the addition amount of the filamentous nickel fine particles is calculated such that the filamentous nickel fine particles occupy 30.0% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S (Table 4).

(2) Preparation of silver powder-containing polyimide precursor solution O A silver powder-containing polyimide precursor solution O was prepared in the same manner as in Example 11.

(3) Preparation of resistance exothermic seamless tubular material First, a polyamic acid solution (composition BPDA / PPD, solid content 17.0% by mass) was uniformly applied to the surface of a cylindrical mold whose surface was release-treated, The coating film was heated at 100 ° C. for 10 minutes and at 120 ° C. for 20 minutes to obtain a tubular base layer having a thickness of 50 μm.

  Next, after uniformly applying the conductive fine particle-containing polyimide precursor solution S to the surface of the base layer, the coating film was applied at 100 ° C. for 10 minutes, 150 ° C. for 20 minutes, 250 ° C. for 30 minutes, and 400 ° C. for 15 minutes. The polyimide tubular product F was produced by sequentially heating under the above conditions to remove the solvent and imidize. When this polyimide tubular product F was extracted from the cylindrical mold and the thickness, inner diameter and length were measured, the thickness was 70 μm, the inner diameter was 18 mm, and the length was 265 mm.

  Next, after uniformly applying the silver powder-containing polyimide precursor solution O to the surfaces of both ends 25 mm of the polyimide tubular product F, the coating film is 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, Heating was performed sequentially at 300 ° C. for 60 minutes and at 350 ° C. for 30 minutes to remove the solvent and imidization treatment to form electrodes having a thickness of 20 μm on both ends of the polyimide tubular product F.

  Next, the polyamic acid solution (composition BPDA / PPD, solid content) is added to the “outer surface of the central portion of the polyimide tubular article F on which no electrode is formed” and “the outer surface of the portion 5 mm from the end on the central portion side of the electrode”. 17.0% by mass), and the coating was applied in order under the conditions of 100 ° C. for 30 minutes, 150 ° C. for 60 minutes, 200 ° C. for 60 minutes, 300 ° C. for 60 minutes, and 350 ° C. for 30 minutes. The insulating layer was formed by heating to remove the solvent and imidization treatment. As a result, a resistance exothermic seamless tubular product having a thickness of 120 μm, an inner diameter of 18 mm, and a length of 265 mm was obtained. In addition, the distance between electrodes of this resistance heat generation seamless tubular thing was 215 mm.

(4) Measurement of initial resistance value The initial resistance value of the resistance exothermic seamless tubular material was measured in the same manner as in Example 11. The initial resistance value was 23.8Ω (see Table 4).

(5) Measurement of resistance value after exposure at 300 ° C. for 100 hours In the same manner as in Example 11, when the resistance value after the resistance exothermic seamless tubular product was left in a 300 ° C. environment for 100 hours was measured, the value was 47.6Ω (see Table 4).

(6) Calculation of resistance value fluctuation rate In the same manner as in Example 11, when the resistance value fluctuation rate of the resistance heating seamless tubular product was calculated, the value was + 100% (= (47.6Ω-23.8Ω) / 23.8Ω × 100) (see Table 4).

(7) Observation of electrode deterioration When electrode deterioration was observed in the same manner as in Example 11, electrode deterioration was observed in this resistance heating seamless tubular material (see Table 4).

(Comparative Example 4)
Comparative Example 3 except that NMP was not added and the amount of filamentary nickel fine particles was changed to 41.88 g, and 0.9160 g of boric acid (manufactured by Nacalai Tesque) was added to the conductive fine particle-containing polyimide precursor solution S. Then, a resistance exothermic seamless tubular product was prepared, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and the deterioration of the electrode was observed. In this comparative example, the filamentous nickel fine particle accounts for 45.0% by volume and the boric acid accounts for 2.8% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S. The amount of nickel fine particles and boric acid added are calculated (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 25.5Ω (see Table 4). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 89.3Ω (see Table 4). When the resistance value fluctuation rate was calculated, it was + 250% (= (89.3Ω−25.5Ω) /25.5Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 5)
Without adding NMP, the amount of filamentary nickel fine particles was changed to 38.16 g, and conductive fine particle-containing polyimide precursor solution S was added with carbon nanofiber (VGCF-H, Showa Denko KK) 0.8370 g and boric acid (Nacalai). Except for adding 0.9160 g), a resistance exothermic seamless tubular material was prepared in the same manner as in Comparative Example 3, and the resistance characteristics of the resistance exothermic seamless tubular material were measured in the same manner as in Example 11 and the electrode was deteriorated. Was observed. In this comparative example, the filamentous nickel fine particles occupy 41.0% by volume, the carbon nanofibers occupy 4.0% by volume, and boric acid is contained in the solid content of the conductive fine particle-containing polyimide precursor solution S. The addition amount of filamentary nickel fine particles, carbon nanofibers and boric acid is calculated so as to occupy 2.8% by volume (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 38.1Ω (see Table 4). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 171.8Ω (see Table 4). When the resistance value fluctuation rate was calculated, it was + 351% (= (171.8Ω−38.1Ω) /38.1Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 6)
The amount of NMP added is changed to 6.35 g, the amount of filamentary nickel fine particles added is changed to 26.53 g, and the conductive nanoparticle-containing polyimide precursor solution S is added with carbon nanofiber (Showa Denko VGCF-H) 2. Except for adding 981 g, TTCA-3Na 0.544 g, and PMoA 0.632 g, a resistance exothermic seamless tubular product was prepared in the same manner as in Comparative Example 3, and the resistance characteristics of the resistance exothermic seamless tubular product were determined in the same manner as in Example 11. The electrode deterioration was observed while measuring. In this comparative example, the filamentous nickel fine particles occupy 29.3% by volume and the carbon nanofibers occupy 14.6% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S. The addition amount of filamentary nickel fine particles, carbon nanofibers, TTCA-3Na and PMoA is calculated so that 3Na occupies 0.5% by volume and PMoA occupies 2.0% by volume (see Table 4).

  The initial resistance value of this resistance exothermic seamless tubular product was 29.9Ω (see Table 4). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 46.3Ω (see Table 4). When the resistance value fluctuation rate was calculated, it was + 55% (= (46.3Ω−29.9Ω) /29.9Ω×100) (see Table 4). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 7)
Without adding NMP, 20.84 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with 35.37 g of flaky nickel fine particles (HCA-1 made by NOVAMET), and carbon nanofibers were added to the conductive fine particle-containing polyimide precursor solution S ( A resistance exothermic seamless tubular product was prepared in the same manner as in Comparative Example 3 except that 0.9910 g (Showa Denko VGCF-H) was added. And the deterioration of the electrode was observed. In addition, in this comparative example, with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S, the scaly nickel fine particles occupy 40.0% by volume, and the carbon nanofibers occupy 5.0% by volume. The addition amount of scaly nickel fine particles and carbon nanofibers is calculated (see Table 4).

  The initial resistance value of the resistance heating seamless tubular product was 14.3Ω (see Table 4). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 46.3Ω (see Table 4). When the resistance value fluctuation rate was calculated, the value was + 224% (= (46.3Ω-14.3Ω) /14.3Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 8)
Without adding NMP, 20.84 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with 25.64 g of flaky nickel fine particles (HCA-1 made by NOVAMET), and carbon nanofibers were added to polyimide precursor solution S containing conductive fine particles ( A resistance exothermic seamless tubular product was prepared in the same manner as in Comparative Example 3 except that 3.180 g of VGCF-H manufactured by Showa Denko KK was added, and the resistance characteristics of the resistance exothermic seamless tubular product were obtained in the same manner as in Example 11. And the deterioration of the electrode was observed. In this comparative example, with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S, the scaly nickel fine particles occupy 29.0% by volume, and the carbon nanofibers occupy 16.0% by volume. The addition amount of scaly nickel fine particles and carbon nanofibers is calculated (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 59.3Ω (see Table 4). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 226.5Ω (see Table 4). When the resistance value fluctuation rate was calculated, the value was + 282% (= (226.5Ω-59.3Ω) /59.3Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 9)
Without adding NMP, 20.84 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with 41.88 g of flaky nickel fine particles (HCA-1 made by NOVAMET), and boronic acid (Nacalai Tesque) was added to the polyimide precursor solution S containing conductive fine particles. (Manufactured) Except that 0.9160 g was added, a resistance exothermic seamless tubular product was prepared in the same manner as in Comparative Example 3, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and electrode degradation was observed. Observed. In this comparative example, the scale-like nickel fine particles account for 45.0% by volume and the boric acid accounts for 2.8% by volume with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S. The amount of nickel fine particles and boric acid added are calculated (see Table 4).

  The initial resistance value of this resistance exothermic seamless tubular product was 43.3Ω (see Table 4). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 570.3Ω (see Table 4). When the resistance value fluctuation rate was calculated, it was + 1217% (= (570.3Ω−43.3Ω) /43.3Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 10)
Without adding NMP, 20.84 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with 26.99 g of flaky nickel fine particles (HCA-1 made by NOVAMET), and carbon nanofibers were added to the polyimide precursor solution S containing conductive fine particles ( A resistance exothermic seamless tubular material was prepared in the same manner as in Comparative Example 3 except that 3.347 g of VGCF-H (manufactured by Showa Denko KK) and 0.9160 g of boric acid (manufactured by Nacalai Tesque) were added. The resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this comparative example, the scale-like nickel fine particles occupy 29.0% by volume, the carbon nanofibers occupy 16.0% by volume, and boric acid is contained in the solid content of the conductive fine particle-containing polyimide precursor solution S. The amount of scale-like nickel fine particles, carbon nanofibers and boric acid added is calculated so as to occupy 2.8% by volume (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 157.2Ω (see Table 4). Further, the resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 479.5Ω (see Table 4). When the resistance value fluctuation rate was calculated, the value was + 205% (= (479.5Ω-157.2Ω) /157.2Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 11)
Without adding NMP, 20.84 g of filamentous nickel fine particles (TYPE 525 made by NOVAMET) were replaced with 38.16 g of scaly nickel fine particles (HCA-1 made by NOVAMET), and carbon nanofibers were added to the polyimide precursor solution S containing conductive fine particles ( A resistance exothermic seamless tubular material was prepared in the same manner as in Comparative Example 3 except that 0.8370 g of VGCF-H (manufactured by Showa Denko KK) and 0.9160 g of boric acid (manufactured by Nacalai Tesque) were added. The resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this comparative example, the scale-like nickel fine particles occupy 41.0% by volume, the carbon nanofibers occupy 4.0% by volume, and boric acid in the solid content of the conductive fine particle-containing polyimide precursor solution S. The amount of scale-like nickel fine particles, carbon nanofibers and boric acid added is calculated so as to occupy 2.8% by volume (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 62.5Ω (see Table 4). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 879.4Ω (see Table 4). When the resistance value fluctuation rate was calculated, it was + 1307% (= (879.4Ω−62.5Ω) /62.5Ω×100) (see Table 4). Moreover, electrode degradation was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 12)
The amount of NMP added is changed to 6.35 g, and the filamentous nickel fine particles (TYPE 525 manufactured by NOVAMET) are replaced by 26.53 g of the scale-like nickel fine particles (NOVAMET HCA-1). A resistance exothermic seamless tubular material was produced in the same manner as in Comparative Example 3 except that 2.981 g of carbon nanofibers (VGCF-H manufactured by Showa Denko KK), 0.544 g of TTCA-3Na and 0.632 g of PMoA were added to In the same manner as in Example 11, the resistance characteristics of the resistance exothermic seamless tubular material were measured, and electrode deterioration was observed. In this comparative example, the scale-like nickel fine particles occupy 29.3% by volume, the carbon nanofibers occupy 14.6% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S. The addition amounts of the scaly nickel particles, carbon nanofibers, TTCA-3Na and PMoA are calculated so that 3Na occupies 0.5% by volume and PMoA occupies 2.0% by volume (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 20.2Ω (see Table 4). Moreover, the resistance value after leaving the resistance exothermic seamless tubular article in a 300 ° C. environment for 100 hours was 32.5Ω (see Table 4). When the resistance value fluctuation rate was calculated, the value was + 61% (= (32.5Ω-20.2Ω) /20.2Ω×100) (see Table 4). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 13)
The amount of NMP added is changed to 5.56 g, the filamentous nickel fine particles (NOVAMET TYPE 525) 20.84 g are replaced with scaly nickel fine particles (NOVAMET HCA-1) 26.53 g, and conductive fine particle-containing polyimide precursor solution S Except that 2.981 g of carbon nanofiber (Showa Denko VGCF-H), 0.534 g of TTCA-3Na and 0.06516 g of 85 wt% phosphoric acid aqueous solution (manufactured by Nacalai Tesque) were added. Then, a resistance exothermic seamless tubular product was prepared, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and the electrode deterioration was observed. In this comparative example, the scale-like nickel fine particles occupy 29.8% by volume, the carbon nanofibers occupy 14.9% by volume, and TTCA- with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S. The addition amount of scaly nickel fine particles, carbon nanofibers, TTCA-3Na and phosphoric acid is calculated so that 3Na occupies 0.5% by volume and phosphoric acid occupies 0.3% by volume (see Table 4). ).

  The initial resistance value of the resistance exothermic seamless tubular product was 38.4Ω (see Table 4). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 201.2Ω (see Table 4). The resistance value fluctuation rate was calculated and found to be + 424% (= (201.2Ω-38.4Ω) /38.4Ω×100) (see Table 4). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 4).

(Comparative Example 14)
The amount of NMP added is changed to 6.27 g, and the filamentous nickel fine particles (TYPE 525 manufactured by NOVAMET) are replaced by 26.53 g of flaky nickel fine particles (NOVAMET HCA-1), and the conductive fine particle-containing polyimide precursor solution S is used. Resistant in the same manner as Comparative Example 3 except that 2.981 g of carbon nanofiber (VGCF-H manufactured by Showa Denko KK), 0.06483 g of 85 wt% phosphoric acid aqueous solution (manufactured by Nacalai Tesque) and 0.312 g of PMoA were added An exothermic seamless tubular product was prepared, and the resistance characteristics of the resistance exothermic seamless tubular product were measured in the same manner as in Example 11 and electrode deterioration was observed. In this comparative example, the flaky nickel fine particles occupy 29.6% by volume, the carbon nanofibers occupy 14.8% by volume, and phosphoric acid with respect to the solid content of the conductive fine particle-containing polyimide precursor solution S. The amount of scale-like nickel fine particles, carbon nanofibers, and phosphoric acid added is calculated so that occupies 0.3% by volume and PMoA occupies 1.0% by volume (see Table 4).

  The initial resistance value of the resistance exothermic seamless tubular product was 89.3Ω (see Table 4). The resistance value after the resistance exothermic seamless tubular material was left in a 300 ° C. environment for 100 hours was 695.6Ω (see Table 4). When the resistance value fluctuation rate was calculated, it was + 695.6% (= (695.6Ω−89.3Ω) /89.3Ω×100) (see Table 4). Further, no electrode deterioration was observed in this resistance exothermic seamless tubular material (see Table 4).

  The sheet resistance heating element according to the present invention has a feature that the resistance value variation with use is sufficiently small, and is used for an image fixing device of an image forming apparatus such as a copying machine or a laser beam printer and the image fixing device. It can be used as a fixing belt or a fixing tube. The sheet resistance heating element may be in the form of a sheet and is widely used as a heating means in addition to the image fixing device of an image forming apparatus such as a copying machine or a laser beam printer and the use of the image fixing device. Can do.

100, 100a, 100b Resistance exothermic seamless tubular body 112 Exothermic resin layer 120 Electrode (electrode part)

Claims (20)

An exothermic resin layer;
A pair of electrode parts,
A resistance value variation rate calculated by dividing a value obtained by subtracting the initial resistance value between the electrode parts from the resistance value between the electrode parts after 100 hours at a temperature of 300 ° C. by the initial resistance value is A sheet resistance heating element within a range of ± 30%. An exothermic resin layer;
A pair of electrode parts,
A resistance value variation rate calculated by dividing a value obtained by subtracting an initial resistance value between the electrode parts from a resistance value between the electrode parts after 48 hours at a temperature of 300 ° C. by the initial resistance value is A sheet resistance heating element within a range of ± 15%. The exothermic resin layer is formed from a resin containing only a nonmetallic nanofiller containing at least one of carbon nanotubes and carbon nanofibers as a conductive filler,
The planar resistance heating element according to claim 1 or 2, wherein the resin is mainly composed of a polyimide resin. The planar resistance heating element according to claim 3, wherein the heat generating resin layer has a thickness of 20 μm or more. The planar resistance heating element according to claim 3 or 4, wherein a volume fraction of the nonmetallic nanofiller with respect to the heat generating resin layer is in a range of 5% by volume to 100% by volume. The exothermic resin layer is formed from a resin containing conductive particles having a metal surface,
The planar resistance heating element according to claim 1. The planar resistance heating element according to claim 6, wherein the resin further contains a resistance value stabilizing component. The resistance value stabilizing component includes (a) a compound in which at least one of an SH group and an SM group is directly bonded to a nitrogen-containing aromatic heterocyclic ring (where M is a metal or a substituted or unsubstituted ammonium). The planar resistance heating element according to claim 7, further comprising (b) a compound containing boron (B). The resistance stabilizing component includes (c) a compound containing at least one element of molybdenum (Mo), vanadium (V), tungsten (W), titanium (Ti), aluminum (Al), and niobium (Nb). The planar resistance heating element according to claim 8, further comprising: The planar resistance heating element according to claim 6, wherein the resin further contains a carbon nanomaterial. The sheet resistance heating element according to any one of claims 6 to 10, wherein the heat generating resin layer has a thickness of 10 µm or more. The planar resistive heating element according to any one of claims 6 to 11, wherein a volume fraction of the conductive particles is in a range of 20% by volume to 70% by volume. The planar resistance heating element according to any one of claims 1 to 13, wherein an initial resistance value between the electrode portions is in a range of 5Ω to 150Ω. A resin or resin precursor;
Conductive particles having a metal surface;
A resistance value stabilizer,
A conductive particle-containing resin solution containing a solvent. The resistance stabilizer includes (d) a compound in which at least one of an SH group and an SM group is directly bonded to a nitrogen-containing aromatic heterocyclic ring (where M is a metal or a substituted or unsubstituted ammonium). The conductive particle-containing resin solution according to claim 14, further comprising at least (e) boric acid. The conductive particle-containing resin solution according to claim 15, wherein the resistance value stabilizer further includes (f) a polyacid or a salt thereof. The conductive particle-containing resin solution according to claim 14, further comprising a carbon nanomaterial.   A planar resistance heating element obtained by heating a coating film of the conductive particle-containing resin solution according to any one of claims 14 to 17. An exothermic resin layer;
A pair of electrode parts,
A resistance value variation rate calculated by dividing a value obtained by subtracting the initial resistance value between the electrode parts from the resistance value between the electrode parts after 100 hours at a temperature of 300 ° C. by the initial resistance value is Resistance exothermic seamless tubular material in the range of ± 30%. An exothermic resin layer;
A pair of electrode parts,
A resistance value variation rate calculated by dividing a value obtained by subtracting an initial resistance value between the electrode parts from a resistance value between the electrode parts after 48 hours at a temperature of 300 ° C. by the initial resistance value is Resistance exothermic seamless tubular material within ± 15%.