EP0932166A1 - Composition PTC polymère et dispositif de protection de circuits fabriqués à partir de celle-ci - Google Patents

Composition PTC polymère et dispositif de protection de circuits fabriqués à partir de celle-ci Download PDF

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Publication number
EP0932166A1
EP0932166A1 EP98120252A EP98120252A EP0932166A1 EP 0932166 A1 EP0932166 A1 EP 0932166A1 EP 98120252 A EP98120252 A EP 98120252A EP 98120252 A EP98120252 A EP 98120252A EP 0932166 A1 EP0932166 A1 EP 0932166A1
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Prior art keywords
ptc
conductive particles
composition
ptc composition
metal
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EP98120252A
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German (de)
English (en)
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EP0932166B1 (fr
Inventor
Hideo Horibe
Itsuo Nishiyama
Osamu Hiroi
Teijiro Mori
Tatsuya Hayashi
Chie Takahashi
Shiro Murata
Kenichi Nishina
Manabu Sogabe
Masahiro Ishikawa
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Priority claimed from JP1051398A external-priority patent/JP3168262B2/ja
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/027—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/13—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material current responsive

Definitions

  • the present invention relates to an electric material, in particular it relates to a material composition having a positive temperature coefficient (PTC) of resistivity, which undergoes a rapid and sharp increase in resistance over a relatively narrow temperature range as temperature increases, i.e. a polymeric PTC composition, and to a circuit protection device employing the same, which is used for a breaker and the like.
  • PTC positive temperature coefficient
  • the PTC composition having the above-mentioned PTC characteristics has been generally used for a circuit protection element and the like which limits the current-flow in the circuit including a heater, a positive character thermistor, a heat sensor, a battery and the like, under short-circuit condition, and resets the circuit when the cause of the short-circuit is removed.
  • the PTC composition include a circuit protection device incorporated in the circuit which comprises a PTC element made of the PTC composition and at least two electrodes electrically connected thereto, for use in protecting against over-voltage or over-temperature by the temperature self controlling function of the PTC element.
  • the PTC element i.e., the PTC composition needs to have such current limiting performance that can be exhibited repeatedly even under high voltage. Also a sufficiently lowered initial resistivity ( ⁇ L ) and an effective PTC characteristic (a large ⁇ H / ⁇ L ) will improve the current limiting performance of the PTC element.
  • ⁇ H refers to the peak resistivity which is given by a PTC curve at a high temperature.
  • the PTC composition Various materials have been developed as the PTC composition, and one of the conventionally known compositions comprises BaTiO 3 and an oxide of a monovalent or trivalent metal added thereto.
  • This material has a problem that it exhibits NTC (Negative Temperature Coefficient) characteristics immediately after the PTC characteristics are exhibited, thus the current starts to flow again within 1 msec or less.
  • NTC Negative Temperature Coefficient
  • PTC compositions which comprise an organic polymer such as polyethylene (abbreviated as PE), polypropylene and ethylene-acrylic acid copolymer, and conductive particles such as carbon black (abbreviated as CB), carbon fiber, graphite or finely divided metal particles, dispersed therein.
  • PE polyethylene
  • CB carbon black
  • PTC compositions are generally produced by adding, followed by kneading, conductive particles of a necessary amount to one or more kinds of resins which are used as the organic polymer.
  • ⁇ L of the resulting PTC element cannot be lowered to 0.1 ⁇ cm or less, even when the organic polymer is loaded with these conductive particles by closest packing, and when the ⁇ L of the PTC element is decreased to the minimum value as low as 0.1 ⁇ cm, ⁇ H / ⁇ L is decreased as well to be around 100 or so. Accordingly, the current limiting performance cannot be improved sufficiently.
  • the resistivity of the metal particles per se is of the order of 10 -6 ⁇ cm, and it is much lower than 0.05 ⁇ cm that is the resistivity of CB per se. Accordingly, the ⁇ L of the resulting PTC device is expected to be lowered by the use of metal particles such as Cu and Ni, and yet those metal particles have not been used as the conductive particles for PTC compositions in comparison with CB.
  • metal particles such as Cu and Ni
  • those metal particles have not been used as the conductive particles for PTC compositions in comparison with CB.
  • One of the biggest reasons for that is that the PTC compositions containing the conventionally known metal particles, used under large current and high voltage, cause internal arc phenomenon (micro arc is generated between conductive particles) and the composition undergoes electrical breakdown.
  • the metal particles in the PTC composition are molten and the molten metal particles are bonded together to locally form a conductive circuit and the large current is concentrated on a part of the element and the element is destroyed. Discharge is also easily caused in a micro space between the composition and the electrode interface, the resin on the discharged part is degraded, and decomposed, thus the deterioration is accelerated disadvantageously. This inconveniency has been remarkable under an electric voltage of some 10 volts or higher. Accordingly, this type of composition has not been used for a self-reset type over-current protection element.
  • a PTC composition containing both CB and metal particles as conductive particles has been disclosed in the publication of Japanese Patent Laid-Open NO. 64-53503. There, the metal particles are contained in order to improve the heat-conductivity of the PTC composition.
  • the metal particles have a very low resistivity compared to that of CB, thus when metal particles are used as conductive particles in the PTC composition, the resistivity ( ⁇ L ) of the PTC element at an ordinary room temperature is decreased, and the PTC element is naturally expected to show good conductivity, but the conventionally known PTC composition containing the metal particles causes internal arc phenomenon when used under large current and high voltage, and the metal particles are melted and a conductive circuit is locally formed, resulting in the destruction of the composition as well the PTC element. Therefore, the conventionally known PTC composition containing the metal particles has a drawback that it lacks in safety and reliability and cannot protect the circuit repeatedly against the over-current.
  • an object of the present invention is to provide a PTC composition having a low resistance and good conductivity under normal operating conditions, which does not locally form a conductive circuit under large current and high voltage but exhibits PTC characteristics to increase the resistivity of the PTC element, and protects the circuit against over-current. That means, an object of the present invention is to provide a PTC composition having excellent current limiting performance, high safety, and high reliability and which can be used favorably, for example, for a self-reset type over-current protection element.
  • Another object of the present invention is to provide a circuit protection device of high safety and high reliability which has good conductivity under normal operating conditions, which shows excellent current limiting performance even under large current and high voltage and which works with high repeat stability.
  • first constitution of the polymeric PTC composition according to the present invention is a polymeric PTC composition which comprises an organic polymer and conductive particles having a melting point of not less than 2000 °C which are dispersed in the organic polymer, and which are treated by a coupling agent.
  • Second constitution of the polymeric PTC composition according to the present invention is the polymeric PTC composition of the first constitution wherein the conductive particle having an average particle size of 0.01 - 50 microns are used.
  • Third constitution of the polymeric PTC composition according to the present invention is the polymeric PTC composition of the first or second constitution, wherein the conductive particles are contained in an amount of 50 - 99 % by weight based on the composition.
  • Fourth constitution of the polymeric PTC composition according to the present invention is the polymeric PTC composition of the first, second or third constitution wherein the conductive particles are particles containing at least one kind of substance selected from a metal, metal carbide, metal boride, metal siliside and metal nitride.
  • the fifth constitution of the polymeric PTC composition according to the present invention is the polymeric PTC composition of the fourth constitution wherein tungsten is used as the metal.
  • Sixth constitution of the polymeric PTC composition according to the present invention is the polymeric PTC composition of the first constitution wherein the coupling agent is contained in an amount of 0.05 - 10 % by weight based on the conductive particles and the coupling agent is an aluminium type or a titanium type coupling agent.
  • Constitution of the circuit protection device comprises a PTC element in which conductive particles having a melting point of not less than 2000 °C which are treated by a coupling agent are dispersed in an organic polymer, and at least two electrodes which are electrically connected to the PTC element.
  • the polymeric PTC composition according to the present invention comprises an organic polymer and conductive particles having a melting point of not less than 2000 °C that are dispersed in the organic polymer, and that are treated by a coupling agent.
  • the conductive particles having a melting point as high as not less than 2000 °C are not melted and do not form a local conductive circuit in the PTC composition, or in the element, when it is used under large current and high voltage, and even an internal arc is generated, unlike the PTC composition containing the conventional metal particles, therefore the PTC composition, or the PTC element of the present invention is not electrically destroyed. Also, when large current flows, the temperature of the PTC element increases and the resistance increases as well, therefore the circuit can be protected against the over-current.
  • the resistivity of the PTC composition according to the present invention at an ordinary room temperature ( ⁇ L ) can be sufficiently decreased so that good conductivity is exhibited under normal operating conditions and the peak resistance ( ⁇ H ) at an elevated temperature can be increased, that means ⁇ H / ⁇ L can be increased, therefore the flow of current can be securely cut-off when large current flows through the PTC composition.
  • ⁇ L room temperature
  • ⁇ H peak resistance
  • the circuit protection device employing a PTC element comprising this PTC composition functions well repeatedly as a self-reset type over-current protection element.
  • CB is a sublimating substance having no melting point and is not included in the category of the conductive particles according to the present invention.
  • the average particle size of the conductive particle is preferably 0.01 - 50 ⁇ m, more preferably it is 0.1 - 30 ⁇ m.
  • the reason is as follows: when the organic polymer is loaded with the conductive particles, particles having a small average particle size - having a narrow particle size distribution, and being bulky - cannot be loaded in a large amount and the resistivity of the PTC element at an ordinary room temperature is increased. On the other hand, the particles having a large average particle size result in the increase of the resistivity of the PTC element at an ordinary room temperature when the same amount of the particles are loaded in the polymer.
  • FIG. 1 is a characteristic diagram showing the relationship between the particle size of tungsten contained in the PTC element, and the resistivity of the PTC element at an ordinary room temperature; wherein ⁇ (black circle) represents the case wherein the tungsten was loaded in an amount of 90 % by weight, and ⁇ (white circle) represents the case wherein the tungsten was loaded in an amount of 95 % by weight. It is shown that the resistivity of the PTC element at an ordinary room temperature increases with increase in average particle size.
  • the conductive particles having the above-mentioned average particle size a PTC composition having a low resistivity at an ordinary room temperature can be obtained.
  • the conductive particles having various particle sizes can be appropriately selected according to the application and the desired characteristics of the PTC composition.
  • the content of the conductive particles is preferably 50 - 99 % by weight, more preferably it is 70 - 97 % by weight based on the PTC composition.
  • the resistivity at an ordinary room temperature is increased.
  • the content of the conductive particles is increased, the kneading torque during the kneading of the organic polymer with the conductive particles becomes high, and the kneading becomes difficult to carry out and the resulting PTC element shows low elasticity and a weak impact resistance.
  • FIG. 2 is a characteristic diagram showing the relationship between the amount of tungsten loaded and the resistivity of the PTC element at an ordinary room temperature, and it is shown that the resistivity of the PTC element at an ordinary room temperature increases with decrease in amount of tungsten loaded.
  • FIG. 3 is a characteristic diagram showing the relationship between the amount of tungsten loaded and the torque during the kneading, and it is shown that the torque during the kneading increases with increase in amount of tungsten loaded. The measurement was carried out by Laboplastomill equipment under the kneading condition of 200 °C and 50 rpm.
  • any particle can be used as far as it has a melting point of not less than 2000 °C, has such electric conductivity, heat conductivity and fusion resistance to micro arc that are good enough for a PTC composition, and provides excellent PTC characteristics.
  • Particles of a metal, metal carbide, metal boride, metal siliside and metal nitride are used as the conductive particles. These can be used alone or in admixture of two or more kinds, and appropriately selected according to the application and the desired characteristics of the PTC composition.
  • An example of the metal particles includes tungsten (W).
  • the metal carbide include TiC, ZrC, VC, NbC, TaC, Mo 2 C, and WC.
  • the metal nitride include TiN, ZrN, VN, NbN, TaN, and Cr 2 N.
  • the metal siliside include TaSi 2 , MoSi 2 , and WSi 2 .
  • the metal boride include TiB 2 , ZrB 2 , NbB 2 , TaB 2 , CrB, MoB, and WB. (Ti: titanium, Zr: zirconium, V: vanadium, Nb: niobium, Ta: tantalum, Mo: molybdenum, and Cr: chromium.)
  • Tungsten is a metal having the highest melting point (3410 °C) among metal particles, besides tungsten and a tungsten compound of a desired particle size are easily available as they are supplied steadily.
  • organic polymer polyethylene, polyethylene oxide, polybutadiene, polyethylene acrylate, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, polyester, polyamide, polyether, polycaprolactam, fluorinated ethylene-propylene copolymer, chlorinated polyethylene, chlorosulphonated ethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, styrene-acrylonitrile copolymer, polyvinyl chloride, polycarbonate, polyacetal, polyalkylene oxide, polyphenylene oxide, polysulphone and a fluororesin are used according to the present invention and these can be used alone or two or more kinds of the compounds selected from these are used in admixture as a blended polymer.
  • the kind, and the composition ratio of the organic polymer can be appropriately selected according to the desired property, and application.
  • the PTC composition is prepared by mixing the organic polymer, conductive particles and other additives at a desired ratio followed by kneading.
  • the conductive particles can be added to the organic polymer, then kneaded, or both materials can be simultaneously mixed and kneaded.
  • the blending ratio of the organic polymer and the conductive particles can be appropriately selected according to the content of the conductive particles in the desired composition, the kind of the organic polymer, and the kind of the kneaders such as Banbury type mixer, pressure kneader and roll mill, but the amount of the conductive particles loaded shall be within the range of from 50 to 99 % by weight based on the PTC composition.
  • a titanate type coupling agent and an aluminium type coupling agent can be used.
  • the titanate type coupling agent include monoalkoxy type such as isopropyltriisostearoyl titanate, isopropyltrioctanoyl titanate, isopropyldiisostearoylcumylphenyl titanate, isopropyldistearoylmethacryl titanate, isopropyltri(dioctylpyrophosphate) titanate, or tetraisopropyldi(dilaurylphosphite) titanate, isostearoyloxy acetate, isostearoylacryloxy acetate, distearoylethylene titanate, and dimethacrylethylene titanate.
  • an aluminium coupling agent any agent which is effective for improving the adhesion between the metal and the plastic such as acetoalkoxyaluminium diisopropylate can be used.
  • the amount of the above-mentioned coupling agent is 0.05 - 10 % by weight based on the conductive particles in order to improve the environmental resistance properties.
  • additives can be mixed, if necessary, with the above-mentioned organic polymer, conductive particles and the coupling agent.
  • the additive include an antioxidant, a stabilizer, and a flame-retardant such an antimony compound, phosphorus compound, chlorine compound and bromine compound.
  • the PTC composition of the present invention can be used for various uses.
  • the PTC composition can be molded into, illustratively, a film form and metal foil electrodes are bonded on the front and the back surfaces of the film by thermo-compression bonding to form a laminate, then the laminate is cut to a desired size and lead wires are welded on the electrode surface by soldering, brazing, or spot welding and the like to provide a PTC element.
  • the polymeric PTC composition of the present invention shows a low resistance and good conductivity under normal operating conditions, and even under large current and high voltage, the conductive particles are not melted to locally form a conductive circuit, but the resistance is increased due to the PTC characteristics to protect the circuit against the over-current, by dispersing the conductive particles having a melting point of not less than 2000 °C in an organic polymer and by treating the conductive particles with a coupling agent.
  • a polymeric PTC composition having excellent PTC characteristics, and current limiting performance, high safety and long-term reliability (environmental resistance properties) can be obtained.
  • the second constitution of the polymeric PTC composition of the present invention there is an advantage that a polymeric PTC composition having a low resistivity at an ordinary room temperature can be obtained by the use of conductive particles having an average particle size of 0.01 - 50 ⁇ m in the first constitution.
  • the third constitution of the polymeric PTC composition of the present invention there is an advantage that a polymeric PTC composition having a low resistivity at an ordinary room temperature which is more suited for practical use can be obtained by incorporating the conductive particles in the composition in an amount of 50 - 99 % by weight in the first or second constitution.
  • the fourth constitution of the polymeric PTC composition of the present invention there is an advantage that a polymeric PTC composition having excellent PTC characteristics and current limiting performance can be obtained by employing particles containing at least one kind of a metal, metal carbide, metal boride, metal siliside and metal nitride as conductive particles in the first, second or third constitution.
  • the fifth constitution of the polymeric PTC composition of the present invention there is an advantage that a polymeric PTC composition having higher safety and reliability, excellent PTC characteristics and current limiting performance can be obtained by employing tungsten as the metal in the fourth constitution.
  • the sixth constitution of the polymeric PTC composition of the present invention there is an advantage that a polymeric PTC composition having reliable environmental resistance properties, excellent PTC characteristics and current limiting performance can be obtained by incorporating the coupling agent in an amount of 0.05 - 10 % by weight based on the conductive particles and by employing an aluminium type or titanate type coupling agent as the coupling agent.
  • the circuit protection device comprises a PTC element wherein conductive particles having a melting point of not less than 2000 °C, which are treated with a coupling agent are dispersed in an organic polymer, and at least two electrodes which are electrically connected to the PTC element, and it is advantageous since the circuit protection device provides excellent current limiting performance.
  • tungsten having an average particle size of 0.88 ⁇ m, available from Nippon Shinkinzoku Co., Ltd. under the trade name of W-1
  • a titanate type coupling agent available from Ajinomoto Co., Ltd., under the trade name of KR TTS
  • the isopropyl alcohol was removed by filtration and the composition left on the filter paper was dried under vacuum for 24 hours.
  • the produced PTC composition was hot-pressed to provide a plate of 40 x 60 x 1 mm.
  • a polyethylene frame was produced by injection molding on the periphery of the plate for 20 mm to carry out insulation at the cut-off. Then the plate of the PTC composition with the frame was sandwiched between electrodes to provide a PTC element.
  • the characteristic diagram of FIG. 4 shows the PTC curve representing the relationship between the temperature and the resistivity of the PTC element.
  • the resistivity at an ordinary room temperature ( ⁇ L ) was 0.02 ⁇ cm
  • the peak resistivity ( ⁇ H ) was 10 5 ⁇ cm
  • ⁇ H / ⁇ L was 10 7 .
  • the current limiting peak value (the peak current at the cut-off of the over-current: I P ) for the over-current of 50 kA at 300 V was 7.5 kA.
  • FIG. 6 is a schematic illustration of an optical microscope photograph showing the dispersion condition of tungsten particles 2, which are the conductive particles of the PTC composition;
  • FIG. 6 (a) shows the condition before the cut-off (current limiting) test, and
  • FIG. 6 (b) shows the condition after the cut-off test.
  • the FIGs. show that there was no change between the conditions before and after the cut-off test, and that tungsten particles 2 were similarly and homogeneously dispersed in the organic polymer 1.
  • the PTC element having an initial resistivity of 0.02 ⁇ cm was subjected to an environmental test (under high temperature, high humidity of 85 °C and 85 %) and it showed a resistivity of 0.1 ⁇ cm after 1000 hours.
  • the resistivity of a PTC element which had not subjected to the coupling treatment was very much increased from its initial value of 0.02 ⁇ cm to 960 ⁇ cm after 1000 hours.
  • the resistivity of a PTC element which had not been subjected to the coupling treatment was very much increased from its initial value of 0.02 ⁇ cm to 100 ⁇ cm after 300 cycles.
  • tungsten carbide having an average particle size of 0.7 ⁇ m, available from Nippon Shinkinzoku Co., Ltd. under the trade name of WC-10) were added to a solution comprising 1 part by weight of an aluminium type coupling agent (available from Ajinomoto Co., Ltd., under the trade name of AL-M) dissolved in 28 parts by weight of isopropyl alcohol, and mixed for 10 minutes.
  • AL-M aluminium type coupling agent
  • the dried composition (tungsten carbide having subjected to coupling treatment), 10 parts by weight of HDPE (available from Mitsubishi Chemical Co., Ltd., under the trade name of HJ560), and 2 parts by weight of a phenol type antioxidant (available from Ciba-Geigy Ltd., under the trade name of Irganox 1010) were kneaded by Laboplastomill equipment (manufactured by Toyo Seiki Co., Ltd.) at 200 °C for 15 minutes.
  • the produced PTC composition was hot-pressed to provide a plate of 40 x 60 x 1 mm.
  • a polyethylene frame was produced by injection molding on the periphery of the plate for 20 mm to carry out insulation at the cut-off.
  • the plate of the PTC composition with the frame was sandwiched between electrodes to provide a PTC element.
  • the resistivity at an ordinary room temperature ( ⁇ L ) was 0.02 ⁇ cm
  • the peak resistivity ( ⁇ H ) was 10 5 ⁇ cm
  • ⁇ H / ⁇ L was 10 7 .
  • the resistance of the PTC element at a room temperature was 1.5 m ⁇
  • the current limiting peak value for the over-current of 50 kA at 300 V was 8 kA.
  • a PTC element having an initial resistivity of 0.02 ⁇ cm was subjected to an environmental test (under high temperature, high humidity of 85 °C and 85 %), and it showed a resistivity of 0.03 ⁇ cm after 1000 hours.
  • the resistivity of a PTC element which had not been subjected to the coupling treatment was very much increased from its initial value of 0.02 ⁇ cm to 115 ⁇ cm after 1000 hours.
  • a PTC element having an initial resistivity of 0.02 ⁇ cm was subjected to an environmental test (heat shock cycle test : -25 °C for 30 minutes 85 °C for 30 minutes) and it showed a resistivity of 0.15 ⁇ cm after 300 cycles.
  • the resistivity of a PTC element which had not been subjected to the coupling treatment was very much increased from its initial value of 0.02 ⁇ cm to 1.6 ⁇ cm after 300 cycles.
  • Example 3 - 27 The results of current limiting peak value and environmental tests obtained for Examples 1 and 2 and the results of current limiting peak value and environmental tests obtained when the kinds of the polymers, fillers and coupling agents in the PTC compositions are changed (Examples 3 - 27) are summarized in Table 1. It is shown that the coupling treatment does not affect the current limiting peak value but provides good results for the environmental tests (high temperature, high humidity of 85 °C and 85 %, heat shock: -25 °C for 30 minutes 85 °C for 30 minutes).
  • the plate of PTC composition with the frame was sandwiched between electrodes to provide a PTC element.
  • the PTC element having a resistance at a room temperature of 1 m ⁇ , could not cut off the flow of current when large current of 50 kA flowed at high voltage of 300 V.
  • the PTC composition of the Comparative Example was loaded with silver particles having a low melting point, caused internal arc phenomenon (micro arc was generated among the conductive particles) under large current and high voltage, and the PTC composition was electrically destroyed. It is deemed that once the internal arc phenomenon was caused, the heat thereof melted the silver particles in the PTC composition, then the silver particles were bonded together and large current flowed through the bonded part and the composition underwent the electrical breakdown.
  • the PTC element having a resistance at a room temperature of 1 m ⁇ could not cut off the flow of current when large current of 50 kA flowed at high voltage of 300 V. It is deemed that this was because nickel particles in the PTC composition were melted to locally form a conductive circuit as is the case with Comparative Examples 1 and 2.
  • FIG. 7 is a schematic illustration of an optical microscope photograph showing the dispersion condition of nickel particles 3 in the PTC composition
  • FIG. 7 (a) illustrates the condition prior to the cut-off (current limiting) test
  • FIG. 7 (b) illustrates the condition after the cut-off test in which the device was destroyed.
  • the nickel particles 3 Prior to the cut-off test, the nickel particles 3 were homogeneously dispersed in the organic polymer 1, but after the cut-off test, the nickel particles 3 were melted and bonded together to form the bonded part of nickel particles 3a. It is deemed that since the nickel particles 3 in the PTC composition were melted to form the bonded part of nickel particles 3a (i.e. a conductive circuit was formed), the over-current could not be cut off as is the case with Comparative Examples 1 and 2, and the element was destroyed.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Thermistors And Varistors (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
EP19980120252 1998-01-22 1998-10-26 Composition PTC polymère et dispositif de protection de circuits fabriqués à partir de celle-ci Expired - Lifetime EP0932166B1 (fr)

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JP1051398A JP3168262B2 (ja) 1997-02-28 1998-01-22 回路保護装置
JP1051398 1998-01-22

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EP0932166A1 true EP0932166A1 (fr) 1999-07-28
EP0932166B1 EP0932166B1 (fr) 2007-03-21

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2578624A1 (fr) 2011-10-06 2013-04-10 Henkel Italia S.p.A. Thermistors PTC polymériques

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4884163A (en) * 1985-03-14 1989-11-28 Raychem Corporation Conductive polymer devices
EP0696036A1 (fr) * 1994-08-01 1996-02-07 Abb Research Ltd. Procédé de fabrication d'une résistance PTC et résistance obtenue par ce procédé
EP0758131A2 (fr) * 1995-07-25 1997-02-12 TDK Corporation Thermistor PCT organique
EP0780849A2 (fr) * 1995-12-23 1997-06-25 Abb Research Ltd. Méthode de fabrication d'un matériau pour résistance PTC
EP0866471A1 (fr) * 1997-02-28 1998-09-23 Mitsubishi Denki Kabushiki Kaisha Composition CTP polymère et dispositif de protection de circuit fabriqué à partir de cette composition

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4884163A (en) * 1985-03-14 1989-11-28 Raychem Corporation Conductive polymer devices
EP0696036A1 (fr) * 1994-08-01 1996-02-07 Abb Research Ltd. Procédé de fabrication d'une résistance PTC et résistance obtenue par ce procédé
EP0758131A2 (fr) * 1995-07-25 1997-02-12 TDK Corporation Thermistor PCT organique
EP0780849A2 (fr) * 1995-12-23 1997-06-25 Abb Research Ltd. Méthode de fabrication d'un matériau pour résistance PTC
EP0866471A1 (fr) * 1997-02-28 1998-09-23 Mitsubishi Denki Kabushiki Kaisha Composition CTP polymère et dispositif de protection de circuit fabriqué à partir de cette composition

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2578624A1 (fr) 2011-10-06 2013-04-10 Henkel Italia S.p.A. Thermistors PTC polymériques
WO2013050543A1 (fr) 2011-10-06 2013-04-11 Henkel Italia S.P.A. Thermistances polymères à coefficient de température positif
US9249342B2 (en) 2011-10-06 2016-02-02 Henkel Ag & Co. Kgaa Polymeric PTC thermistors

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DE69837378D1 (de) 2007-05-03
DE69837378T2 (de) 2007-11-29

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