CN1581371A - Thermistor material and method for manufacturing thermistor containing same - Google Patents
Thermistor material and method for manufacturing thermistor containing same Download PDFInfo
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- CN1581371A CN1581371A CN 03140215 CN03140215A CN1581371A CN 1581371 A CN1581371 A CN 1581371A CN 03140215 CN03140215 CN 03140215 CN 03140215 A CN03140215 A CN 03140215A CN 1581371 A CN1581371 A CN 1581371A
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- thermistor
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Abstract
The thermistor is composed of sheets of heat-resisting material, metal foils and pole ears. The metal foils are composed on two sides of the sheets of heat-resisting material. Sheet pole ears are welded on external surfaces of metal foils. Heat-resisting material includes polyvinyl resin, conducting filler, inorganic filler and other auxiliary agent. Method for fabricating the thermistor includes steps: fusion, co-fixing, graining, crushing, molding, composing metal foils, irradiation crosslinking, heat treatment, slicing and welding pole ear etc. Comparing with current technique, the invention possesses features of low resistance in room temperature, high positive temperature coefficient (PTC) since special technique of heat treatment is adopted.
Description
[technical field]
The present invention relates to a kind of thermistor material and contain the manufacture method of the thermistor of this material, particularly relate to a kind of positive temperature coefficient (PTC) thermistor material and contain the manufacture method of the thermistor of this material
[background technology]
Conductor with positive temperature coefficient (PTC), in certain temperature range, the resistivity of self can increase with the rising of temperature.The polymer of most partially crystallizables all is insulating properties as polyethylene, polypropylene and PVDF etc., in case but after having mixed conductive powder such as carbon black, metal and metal oxide in these materials, just can have conductivity.Polymer conducting material with positive temperature coefficient (PTC) characteristic, at first found in 1948, the resistivity of such material is very little when lower temperature, and slowly increase with the rising of temperature, and when temperature is elevated near the high molecular polymer fusing point, resistivity sharply raises, and transition reaches several even tens orders of magnitude, thereby has switching characteristic.
The thermistor of being made by the polymer conducting material with ptc characteristics is mainly used in various protective circuits.Electric current when ambient temperature in the lower and circuit relatively hour, the thermistor actuator temperature is lower, be in the low resistance state, and raise or big electric current that fault causes when passing through when ambient temperature is unusual, its temperature is elevated to " switch " temperature, cause its resistance value to become very big, so just make circuit be in a kind of approximate " disconnection " state, thereby protected other element in the circuit; And after fault was got rid of, the temperature of thermistor descended, and its resistance value can return to the state of low resistance again.
The polymer thermistor device has been widely used in various fields such as electronics, communication, automation control, for most of purposes, wishes that thermistor has low room temperature resistance and high PTC intensity.But with regard to present technology, when room temperature resistance is low, the PTC insufficient strength height of thermistor, abundant inadequately to blocking of electric current.
Mechanism about polymer thermistor PTC effect has multiple theory at present, but generally believes that the thermal coefficient of expansion of polymeric matrix is depended in the generation of PTC effect.In the temperature-rise period of composite material, the expansion of polymeric matrix makes the distance between carbon black pellet become big, and resistivity increases, and when temperature during near the polymer crystals fusing point, the unexpected expansion of volume causes conductive network to destroy, and material presents high resistance.The degree of crystallinity of polymeric matrix is high more, during the crystal fusion volumetric expansion big more, present high more PTC intensity.Therefore, improve poly degree of crystallinity, can obtain high PTC intensity by heat treatment.
[summary of the invention]
The purpose of this invention is to provide a kind of room temperature resistance is low, PTC intensity is high thermistor material and with the thermistor of this made.
Technical scheme of the present invention is as follows:
Used thermo-sensitive material is for having the macromolecule conducting material of positive temperature coefficient (PTC) in the thermistor among the present invention, and its prescription is as follows: polyvinyl resin 35-50%, conductive filler 30-45%, inorganic filler 0-15%, other auxiliary agent 1-5%.Wherein, polyvinyl resin can be made up of one or more the blend in low density polyethylene (LDPE), LLDPE, medium density polyethylene, high density polyethylene (HDPE), the ultra-high molecular weight polyethylene.Conductive filler can be made up of one or more the mixture in carbon black, carbon fiber, metal dust, the burning.Inorganic filler can be a kind of in magnesium oxide, calcium oxide, zinc oxide, aluminium oxide, silicon dioxide, the titanium dioxide.Other auxiliary agent is meant antioxidant, photosensitive crosslinker, fire retardant, lubricant, coupling agent.
Described polyvinyl resin, conductive filler, inorganic filler and other processing aid melt blending under the temperature that is higher than the polyvinyl resin fusing point is obtained thermo-sensitive material, this thermo-sensitive material is heat-treated more than the fusing point of polyvinyl resin, slowly cool to room temperature again, cooling rate is lower than 40 ℃/min.
A kind of manufacture method with thermistor of positive temperature coefficient comprises the steps:
(1) with polyvinyl resin, conductive filler, inorganic filler and other processing aid at the temperature melt blending that is higher than 30-60 ℃ of polyvinyl resin fusing point, cooling and dicing or pulverize after, through extruding or the method for mold pressing obtains sheet material;
(2) metal forming hot pressing is compound to the two sides of described sheet material, obtains three layers of composite sheet;
(3) with gamma-rays or electron ray described three layers of composite sheet are carried out cross-linking radiation;
(4) these three layers of composite sheets are placed 1-10min at the above 30-80 of the fusing point of polyvinyl resin ℃, slowly cool to room temperature again, cooling rate should be lower than 40 ℃/min;
(5) three layers of composite sheet after the heat treatment are pressed certain size cutting after, sheet lug in its two sides welding.
The invention has the advantages that: heat treatment process of the present invention makes crystallization again after the polyvinyl resin fusion in the thermo-sensitive material, by the control cooling rate, improve degree of crystallinity, thereby make the thermo-sensitive material of this method manufacturing have the PTC intensity of lower room temperature resistivity and Geng Gao.
The present invention is further illustrated below by embodiment.
[embodiment]
The prescription of the thermo-sensitive material that the present invention makes is as follows: polyvinyl resin 35-50wt%, conductive filler 30-45wt%, inorganic filler 0-15wt%, other auxiliary agent 1-5wt%.
Described polyvinyl resin can be made up of a kind of in low density polyethylene (LDPE), LLDPE, medium density polyethylene, high density polyethylene (HDPE), the ultra-high molecular weight polyethylene or two or more blend wherein.The start-up temperature of polymer thermistor device is relevant with the fusing point of polyvinyl resin, selects the polyvinyl resin of different melting points just can obtain different start-up temperature.
Described conductive filler can be made up of a kind of in carbon black, carbon fiber, metal dust, the metal oxide or two or more mixture wherein.The selected conductive filler of the present invention is a carbon black, the specific area 10-200m of carbon black
2/ g, DBP oil factor 80-500ml/100g.
Described inorganic filler can be a kind of in magnesium oxide, calcium oxide, zinc oxide, aluminium oxide, silicon dioxide, the titanium dioxide.Inorganic filler plays conductive force in thermo-sensitive material, prevent local overheating.
Described other auxiliary agent is meant antioxidant, photosensitive crosslinker, fire retardant, lubricant, coupling agent.Antioxidant generally adopts phenols or ester kind antioxidant.Photosensitive crosslinker is some low-molecular-weight polyfunctional compounds, can improve the efficient of crosslinking with radiation, reduces radiation dose.Fire retardant is the organic substance of some Halogens.Lubricant can be Tissuemat E, hard ester acid etc.Coupling agent can be silane or titante coupling agent.
The manufacture method of positive temperature coefficient of the present invention (PTC) thermistor material comprises the steps:
(1) with polyvinyl resin, conductive filler, inorganic filler and other processing aid at the temperature melt blending that is higher than 30-60 ℃ of polyvinyl resin fusing point, cooling and dicing or pulverize after, through extruding or the method for mold pressing obtains the sheet material of thickness 0.1-2.0mm;
(2) on hot press, metal forming hot pressing is compound to the two sides of described sheet material, obtains three layers of composite sheet;
(3) with gamma-rays or electron ray described three layers of composite sheet are carried out cross-linking radiation, irradiation dose is 5-50Mrad;
(4) three layers of composite sheet behind the irradiation are heat-treated, this heat treatment process is: these three layers of composite sheets are placed 1-10min at the above 30-80 of the fusing point of polyvinyl resin ℃, slowly cool to room temperature again, cooling rate should be lower than 40 ℃/min, preferably is lower than 5 ℃/min;
(5) three layers of composite sheet after the heat treatment are pressed certain size cutting after, sheet lug in its two sides welding promptly obtains thermistor.
The melt blending of each component of thermo-sensitive material can adopt plastics mixing apparatus such as double screw extruder, mill, banbury, and mixing temperature should be higher than 30-60 ℃ of polyvinyl resin fusing point.
The moulding of polymer thermo-sensitive material sheet material can adopt single screw extrusion machine extrusion molding or hot press hot-forming, the sheet thickness 0.1-2.0mm that obtains.
Being compounded on the hot press of three layers of metal forming/thermo-sensitive materials/metal forming carried out, and hot pressing temperature should be higher than 5-50 ℃ of polyvinyl resin fusing point, pressure 1-20Mpa.
The cross-linking radiation of three layers of composite sheet can adopt gamma-rays or electron ray, and irradiation dose is 5-50Mrad.
Embodiment 1
High density polyethylene (HDPE) (density 0.960g/cm
3, melt index 0.35g/10min) and 45wt%, conductive carbon black (DBP oil factor 110-130ml/100g specific area 30-60m2/g) 40wt%, magnesium oxide powder 10wt%, other auxiliary agent 5wt%.Extrude and granulation adding the double screw extruder blend behind above-mentioned each component premix, each section of extruder temperature is 160 ℃, 170 ℃, 180 ℃, 185 ℃, 175 ℃, 160 ℃.The pellet that obtains presses to 10 * 10cm at the hot press patrix
2, thickness 0.2mm sheet material, 170 ℃ of hot press temperature, pressure 10Mpa.The nickel plating Copper Foil that 0.04mm is thick hot pressing under the condition of 160 ℃ of temperature, pressure 8Mpa is compound to the two sides of thermo-sensitive material sheet material.With gamma-rays three layers of composite sheet are carried out cross-linking radiation, irradiation dose is 15Mrad.Three layers of composite sheet behind the irradiation are placed 5min in 190 ℃ baking oven, the speed with 3 ℃/min is cooled to room temperature then.Three layers of composite sheet after the heat treatment are cut into 5 * 10mm
2Small pieces, sheet lug in the welding of its two sides promptly obtains thermistor, the resistance when measuring its 20 ℃ and start after maximum resistance, calculate PTC intensity.
Embodiment 2
Cooling rate is adjusted into the 8 ℃/min in heat treatment, and all the other are with embodiment 1.
Comparative example 1
Do not heat-treat, all the other are with embodiment 1.
Comparative example 2
In heat treatment process, three layers of composite sheet are placed 5min in 190 ℃ baking oven, take out the back at the room temperature environment natural cooling, and all the other are with embodiment 1.
Comparative example 3
In heat treatment process, three layers of composite sheet are placed 5min in 190 ℃ baking oven, rapidly it are transferred in 0 ℃ the refrigerator to cool off, and all the other are with embodiment 1.
Table 1. is the room temperature resistance and the PTC intensity of the thermistor of basis material with the high density polyethylene (HDPE)
| Room temperature resistance | Room temperature resistivity | PTC intensity | Start the back room temperature resistivity for 50 times | Start back PTC intensity for 50 times | |
| Embodiment 1 | ??44-52 | ????1.1-1.3 | ??5×10 7-1×10 8 | ????2.5-3.3 | ??1×10 7-6×10 7 |
| Embodiment 2 | ??47-54 | ????1.2-1.4 | ??1×10 7-6×10 7 | ????2.7-3.6 | ??3×10 6-1×10 7 |
| Comparative example 1 | ??43-52 | ????1.1-1.3 | ??3×10 4-1×10 5 | ????2.6-3.3 | ??1×10 4-4×10 4 |
| Comparative example 2 | ??72-88 | ????1.8-2.2 | ??5×10 4-2×10 5 | ????2.9-3.9 | ??1×10 4-5×10 4 |
| Comparative example 3 | ??88-112 | ????2.2-2.8 | ??1×10 4-7×10 4 | ????3.0-4.2 | ??8×10 3-2×10 4 |
Wherein the unit of room temperature resistance is m Ω, and the unit of room temperature resistivity is Ω cm.
Claims (5)
1. thermistor material with positive temperature coefficient, it is composed as follows: polyvinyl resin 35-50%, conductive filler 30-45%, inorganic filler 0-15%, other auxiliary agent 1-5%; Wherein, polyvinyl resin can be made up of one or more the blend in low density polyethylene (LDPE), LLDPE, medium density polyethylene, high density polyethylene (HDPE), the ultra-high molecular weight polyethylene, conductive filler can be made up of one or more the mixture in carbon black, carbon fiber, metal dust, the burning, inorganic filler can be a kind of in magnesium oxide, calcium oxide, zinc oxide, aluminium oxide, silicon dioxide, the titanium dioxide, and other auxiliary agent is meant antioxidant, photosensitive crosslinker, fire retardant, lubricant, coupling agent;
Described polyvinyl resin, conductive filler, inorganic filler and other processing aid melt blending under the temperature that is higher than the polyvinyl resin fusing point is obtained thermo-sensitive material, this thermo-sensitive material is heat-treated more than the fusing point of polyvinyl resin, slowly cool to room temperature again, cooling rate is lower than 40 ℃/min.
2. the thermistor material with positive temperature coefficient as claimed in claim 1 is characterized in that: the chilling temperature after heat treatment process is lower than 5 ℃/min.
3. the manufacture method of a positive temperature coefficient (PTC) thermistor comprises the steps:
(1) polyvinyl resin, conductive filler, inorganic filler and other processing aid are carried out melt blending more than the polyvinyl resin melting temperature, cooling and dicing or pulverize after, through extruding or the method for mold pressing obtains sheet material;
(2) metal forming hot pressing is compound to the two sides of described sheet material, obtains three layers of composite sheet;
(3) with gamma-rays or electron ray described three layers of composite sheet are carried out cross-linking radiation;
(4) these three layers of composite sheets are placed 1-10min at the above 30-80 of the fusing point of polyvinyl resin ℃, slowly cool to room temperature again, cooling rate should be lower than 40 ℃/min;
(5) three layers of composite sheet after the heat treatment are pressed certain size cutting after, at its two sides soldering polar ear.
4. the manufacture method of positive temperature coefficient thermistor according to claim 3 is characterized in that: the compound temperature of hot pressing in the step (2) is higher than 5-50 ℃ of poly-second melting point resin, and pressure is 1-20Mpa.
5. the manufacture method of positive temperature coefficient thermistor according to claim 3, it is characterized in that: the irradiation dose in the step (3) is 5-50Mrad.
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| CN 03140215 CN1581371A (en) | 2003-08-15 | 2003-08-15 | Thermistor material and method for manufacturing thermistor containing same |
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|---|---|---|---|
| CN 03140215 CN1581371A (en) | 2003-08-15 | 2003-08-15 | Thermistor material and method for manufacturing thermistor containing same |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100348694C (en) * | 2004-05-21 | 2007-11-14 | 中国石油天然气股份有限公司 | Flame-retardant resin composition with positive resistance temperature coefficient |
| CN100437840C (en) * | 2005-02-24 | 2008-11-26 | 深圳市固派电子有限公司 | Macromolecular thermosensitive resistor and method for making same |
| CN101565524B (en) * | 2009-04-28 | 2011-04-27 | 华南理工大学 | HDPE-carbon fiber-zinc oxide crystal whisker conductive composite material and preparation method thereof |
| CN102167858A (en) * | 2010-02-26 | 2011-08-31 | 比亚迪股份有限公司 | Positive temperature coefficient material, preparation method thereof and thermistor containing material |
| CN102307403A (en) * | 2011-09-02 | 2012-01-04 | 西安盖沃热能科技有限公司 | Self-limiting temperature electrothermal membrane of PTC high-molecular conductive fiber and preparation method thereof |
| CN102427617A (en) * | 2011-09-02 | 2012-04-25 | 西安盖沃热能科技有限公司 | Unidirectional heat transfer flame retardation PTC macromolecule self-limiting temperature electrothermal film and preparation method thereof |
| CN102427616A (en) * | 2011-09-02 | 2012-04-25 | 西安盖沃热能科技有限公司 | Flame-retarded PTC high polymer self-limiting temperature electric heating film and preparation method thereof |
| CN102634095A (en) * | 2012-03-29 | 2012-08-15 | 常熟市新港农产品产销有限公司 | Anti-static degradable packaging bag applied to electronics industry |
| CN103333387A (en) * | 2013-05-29 | 2013-10-02 | 安徽荣玖光纤通信科技有限公司 | PCT polymer conductive material adopting high-density polyethylene as main material and preparation method thereof |
| CN106117977A (en) * | 2016-07-05 | 2016-11-16 | 安徽吉安特种线缆制造有限公司 | A kind of preparation of explosion-proof resistance to compression accompanying-heat cable core material |
| CN106211387A (en) * | 2016-07-05 | 2016-12-07 | 安徽吉安特种线缆制造有限公司 | A kind of composite high-molecular self limiting temperature accompanying-heat cable |
| CN108822492A (en) * | 2018-05-23 | 2018-11-16 | 江苏时瑞电子科技有限公司 | A kind of macromolecular PTC thermistor material and preparation method thereof |
| CN110317469A (en) * | 2019-06-26 | 2019-10-11 | 电子科技大学中山学院 | A kind of positive temperature coefficient thermoplasticity thermistor composite material and preparation method thereof |
| CN112094449A (en) * | 2020-09-16 | 2020-12-18 | 东莞市竞沃电子科技有限公司 | Curie point adjustable PTC polymer conductive composite material and preparation method thereof |
-
2003
- 2003-08-15 CN CN 03140215 patent/CN1581371A/en active Pending
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100348694C (en) * | 2004-05-21 | 2007-11-14 | 中国石油天然气股份有限公司 | Flame-retardant resin composition with positive resistance temperature coefficient |
| CN100437840C (en) * | 2005-02-24 | 2008-11-26 | 深圳市固派电子有限公司 | Macromolecular thermosensitive resistor and method for making same |
| CN101565524B (en) * | 2009-04-28 | 2011-04-27 | 华南理工大学 | HDPE-carbon fiber-zinc oxide crystal whisker conductive composite material and preparation method thereof |
| CN102167858B (en) * | 2010-02-26 | 2013-06-19 | 比亚迪股份有限公司 | Positive temperature coefficient material, preparation method thereof and thermistor containing material |
| CN102167858A (en) * | 2010-02-26 | 2011-08-31 | 比亚迪股份有限公司 | Positive temperature coefficient material, preparation method thereof and thermistor containing material |
| CN102307403A (en) * | 2011-09-02 | 2012-01-04 | 西安盖沃热能科技有限公司 | Self-limiting temperature electrothermal membrane of PTC high-molecular conductive fiber and preparation method thereof |
| CN102427616A (en) * | 2011-09-02 | 2012-04-25 | 西安盖沃热能科技有限公司 | Flame-retarded PTC high polymer self-limiting temperature electric heating film and preparation method thereof |
| CN102427617A (en) * | 2011-09-02 | 2012-04-25 | 西安盖沃热能科技有限公司 | Unidirectional heat transfer flame retardation PTC macromolecule self-limiting temperature electrothermal film and preparation method thereof |
| CN102427617B (en) * | 2011-09-02 | 2013-07-10 | 西安盖沃热能科技有限公司 | Unidirectional heat transfer flame retardation PTC macromolecule self-limiting temperature electrothermal film and preparation method thereof |
| CN102634095A (en) * | 2012-03-29 | 2012-08-15 | 常熟市新港农产品产销有限公司 | Anti-static degradable packaging bag applied to electronics industry |
| CN103333387A (en) * | 2013-05-29 | 2013-10-02 | 安徽荣玖光纤通信科技有限公司 | PCT polymer conductive material adopting high-density polyethylene as main material and preparation method thereof |
| CN103333387B (en) * | 2013-05-29 | 2016-08-10 | 安徽琦迅强电子科技有限公司 | A kind of high density polyethylene (HDPE) is PTC high-molecular conductive material of major ingredient and preparation method thereof |
| CN106117977A (en) * | 2016-07-05 | 2016-11-16 | 安徽吉安特种线缆制造有限公司 | A kind of preparation of explosion-proof resistance to compression accompanying-heat cable core material |
| CN106211387A (en) * | 2016-07-05 | 2016-12-07 | 安徽吉安特种线缆制造有限公司 | A kind of composite high-molecular self limiting temperature accompanying-heat cable |
| CN108822492A (en) * | 2018-05-23 | 2018-11-16 | 江苏时瑞电子科技有限公司 | A kind of macromolecular PTC thermistor material and preparation method thereof |
| CN110317469A (en) * | 2019-06-26 | 2019-10-11 | 电子科技大学中山学院 | A kind of positive temperature coefficient thermoplasticity thermistor composite material and preparation method thereof |
| CN112094449A (en) * | 2020-09-16 | 2020-12-18 | 东莞市竞沃电子科技有限公司 | Curie point adjustable PTC polymer conductive composite material and preparation method thereof |
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