The background skill originally
Usually, in the crystallization of filled conductive particle or hypocrystalline polymer composite, can show positive temperature coefficient PTC (positivetemperaturecoefficient) phenomenon.That is to say that in certain temperature range, the resistivity of self can increase with the rising of temperature.These crystallizations or semi-crystalline polymer comprise polyethylene, polypropylene, Kynoar, polytrifluorochloroethylene etc., and their copolymer.Conducting particles comprises the glass microballoon of carbon black, graphite, carbon fiber, metal dust (as silver powder, copper powder, aluminium powder, nickel powder, stainless steel powder etc.), metal oxide and plating metal on surface etc.When lower temperature, this class conductor presents lower resistivity, is elevated to it more than high molecular polymer fusing point and work as temperature, during just so-called " shutoff " temperature, and the hurried rising of resistivity.This class electric conductor with ptc characteristics has been made thermistor, is applied to the overcurrent protection setting of circuit.In the normal state; electric current in the circuit is less relatively; the thermistor actuator temperature is lower; and when the big electric current that is caused by fault passes through this from the renaturation fuse; its temperature can be elevated to " shutoff " temperature suddenly; cause its resistance value to become very big, so just make circuit be in a kind of approximate " open circuit " state, thereby protected other elements in the circuit.And after fault was got rid of, the temperature of thermistor descended, and its resistance value can return to the low resistance state again.
Thermistor has been widely applied in the various fields such as communication, computer, automobile, Industry Control, electronics.At present the ptc characteristics of the low resistance high molecular PTC material that occurs is relatively poor, that is to say reach " shutoff " temperature after, its PTC intensity is less, can not play good overcurrent protection.
Summary of the invention
Purpose of the present invention is exactly to provide a kind of thermistor that has than low resistance, higher PTC intensity for the defective that overcomes above-mentioned prior art existence.
Purpose of the present invention can realize in the following manner: a kind of thermistor, it is characterized in that it is by core and be covered on the tinsel on above-mentioned core two sides, the insulating barrier that is welded on sheet on this tinsel outer surface or lead-in wire shape extraction electrode and is coated on outer surface constitutes; Described core is at first by the mixing masterbatch of making of high molecular polymer, conductive filler, inorganic filler and processing aid, the percetage by weight prescription of this masterbatch is as follows: high molecular polymer 35%~60%, conductive filler 35%~60%, inorganic filler 0~20%, processing aid 0.1~5%; Then with masterbatch: high molecular polymer: conductive filler: inorganic filler: processing aid=100: (45~50): (45~50): (0~10): the part by weight of (1.25~1.5) is mixing once more to be obtained.
High molecular polymer is the blend of a kind of polymer or two or more polymer in the described core component, comprises polyethylene, polypropylene, Kynoar, polytrifluorochloroethylene, and their copolymer.
Conductive filler is following one or more mixtures of material in the described core component, comprises carbon black, graphite, carbon fiber, metal dust, metal oxide.
Inorganic filler is the inorganic matter of particle diameter<50 μ m in the described core component, comprises magnesium oxide, aluminium oxide, silicon dioxide, potter's clay, talcum powder, calcium carbonate, magnesium hydroxide, aluminium hydroxide.
Processing aid is meant antioxidant, crosslinking accelerator, coupling agent in the described core component, and wherein antioxidant is phenols or aminated compounds, and crosslinking accelerator is the polyfunctional group unsaturated compound, and coupling agent is silane or titanate ester organic compound.
A kind of manufacture method of thermistor is characterized in that, core component high molecular polymer, conductive filler, inorganic filler and processing aid is mixing under 100~200 ℃ of temperature, and granulation is with gamma-rays (Co
60) or electron beam to irradiate crosslinked make masterbatch, irradiation dose 1~10Mrad, the percetage by weight of this masterbatch prescription is as follows: high molecular polymer 35%~60%, conductive filler 35%~60%, inorganic filler 0~20%, processing aid 0.1~5%; Then with masterbatch: high molecular polymer: conductive filler: inorganic filler: processing aid=100: (45~50): (45~50): (0~10): the part by weight of (1.25~1.5) is mixing once more under 100~200 ℃ of temperature, and making area with mold pressing or the method extruded is 100~1000cm
2, the sheet material of thick 0.1~1.0mm is compound in tinsel two surfaces of above-mentioned sheet material then on hot press with the method for hot pressing, make composite sheet, and then with this composite sheet with gamma-rays (Co
60) or electron beam to irradiate crosslinked, dosage is 5~100Mrad.
Compared with prior art, advantage of the present invention is to have adopted follow-on mixing procedure, has both had than low resistance, has high PTC intensity again.
Embodiment
Embodiment 1:
Table 1 unit: g
High density polyethylene (HDPE) | Carbon black | Phenolic antioxidant ANOX70 | Triallyl isocyanurate | Titanium coupling agent TCF |
380 | 380 | 2 | 2 | 1 |
Annotate: 135 ℃ of high density polyethylene (HDPE) fusing points
Table 2 unit: g
Masterbatch | High density polyethylene (HDPE) | Carbon black | Phenolic antioxidant ANOX70 | Triallyl isocyanurate | Titanium coupling agent TCF |
400 | 200 | 200 | 2 | 2 | 1 |
Annotate: 135 ℃ of high density polyethylene (HDPE) fusing points
Each component in the table 1 is mixing even in banbury under 200 ℃ of temperature, through cooling, pulverize back gamma-rays (Co
60) irradiation, dosage is that 3Mrad makes masterbatch.
Each component in the table 2 is mixing even in banbury under 200 ℃ of temperature, through cooling, place it in after the pulverizing in the pressing mold, pressure 5Mpa is pressed into area 100cm under 180 ℃ of conditions of temperature
2, thick 0.2mm sheet material after smooth, at pressure 5Mpa, is hot-pressed onto the two-sided of core under 180 ℃ of conditions of temperature with the nickel sheet behind the surface coarsening, and 80 ℃ of heat treatments are after 8 hours, with gamma-rays (Co in vacuum drying oven
60) irradiation, dosage is 20Mrad, strike out the small pieces of 5 * 12mm then, and then the thick 0.10mm that burn-ons respectively on the two sides, the sheet metal electrode of 4 * 10mm size, can make the thermistor of the polymer about zero power resistance 0.10 Ω, the ratio of its resistance value and its resistance value in the time of 20 ℃ in the time of 135 ℃
Be not less than 10
5
Embodiment 2:
Prescription is with embodiment 1
Each component in the table 1 is mixing even in banbury under 200 ℃ of temperature, through cooling, pulverize back gamma-rays (Co
60) irradiation, dosage is that 3Mrad makes masterbatch.
Each component in the table 2 is mixing even in banbury under 200 ℃ of temperature, through cooling, place it in after the pulverizing in the pressing mold, pressure 5Mpa is pressed into area 100cm under 180 ℃ of conditions of temperature
2, thick 0.2mm sheet material after smooth, at pressure 5Mpa, is hot-pressed onto the two-sided of core under 180 ℃ of conditions of temperature with the nickel sheet behind the surface coarsening, and 80 ℃ of heat treatments are after 8 hours, with gamma-rays (Co in vacuum drying oven
60) irradiation, dosage is 20Mrad, strike out the small pieces of 6 * 6mm then, and then the thick 0.60mm that burn-ons respectively on the two sides, two conductive pin of 6 * 8mm and 6 * 6mm size, can make the surface mount polymer thermistor device about zero power resistance 0.15 Ω, the ratio of its resistance value and its resistance value in the time of 20 ℃ in the time of 135 ℃
Be not less than 10
5
Embodiment 3~4
Radiation mode changes electron beam irradiation into, and irradiation dose is identical with embodiment 1~2 respectively with other conditions, can obtain 1~2 similar product with embodiment.
Embodiment 5~8
Mixing method is used extruder instead and is extruded, and the control of each section of extruder temperature is set at respectively:
150℃ 160℃ 170℃ 180℃
Other conditions are identical with embodiment 1~4 respectively, obtain the product similar to embodiment 1~4 respectively.
Embodiment 9
Table 3 unit: g
High density polyethylene (HDPE) | Carbon black | Phenolic antioxidant ANOX70 | Triallyl isocyanurate | Titanium coupling agent TCF |
410 | 370 | 2 | 2 | 2 |
Annotate: 135 ℃ of high density polyethylene (HDPE) fusing points
Table 4 unit: g
Masterbatch | High density polyethylene (HDPE) | Carbon black | Magnesium hydroxide | Phenolic antioxidant ANOX70 | Triallyl isocyanurate | Titanium coupling agent TCF |
400 | 180 | 180 | 40 | 2 | 2 | 2 |
Annotate: 135 ℃ of high density polyethylene (HDPE) fusing points
Each component in the table 3 is mixing even in banbury under 200 ℃ of temperature, through cooling, pulverize back gamma-rays (Co
60) irradiation, dosage is that 3Mrad makes masterbatch.
Each component in the table 4 is mixing even in banbury under 200 ℃ of temperature, through cooling, place it in after the pulverizing in the pressing mold, pressure 5Mpa is pressed into area 100cm under 180 ℃ of conditions of temperature
2, thick 0.2mm sheet material after smooth, at pressure 5Mpa, is hot-pressed onto the two-sided of core under 180 ℃ of conditions of temperature with the nickel sheet behind the surface coarsening, and 80 ℃ of heat treatments are after 8 hours, with gamma-rays (Co in vacuum drying oven
60) irradiation, dosage is 20Mrad, strikes out the sequin of φ 6.7mm then, the φ 0.6mm tin-coated copper of burn-oning respectively on the two sides again lead-in wire is sealed the material package envelope with epoxy then, can make and the similar polymer thermistor device of embodiment 1 electrical property.
Embodiment 10
Radiation mode changes electron beam irradiation into, and irradiation dose is identical with embodiment 9 respectively with other conditions, can obtain the 9 similar products with embodiment.
Embodiment 11~12
Mixing method is used extruder instead and is extruded, and the control of each section of extruder temperature is set at respectively:
150℃ 160℃ 170℃ 180℃
Other conditions are identical with embodiment 9~10 respectively, obtain the product similar to embodiment 9~10 respectively.
Embodiment 13
Each component in the table 3 is mixing even in banbury under 200 ℃ of temperature, through cooling, pulverize back gamma-rays (Co
60) irradiation, dosage is that 3Mrad makes masterbatch.
Each component in the table 4 is mixing even in banbury under 200 ℃ of temperature, through cooling, place it in after the pulverizing in the pressing mold, pressure 5Mpa is pressed into area 100cm under 180 ℃ of conditions of temperature
2, thick 0.2mm sheet material after smooth, at pressure 5Mpa, is hot-pressed onto the two-sided of core under 180 ℃ of conditions of temperature with the nickel sheet behind the surface coarsening, and 80 ℃ of heat treatments are after 8 hours, with gamma-rays (Co in vacuum drying oven
60) irradiation, dosage is 20Mrad, strike out the small pieces of 4.5 * 3.3mm then, go out the hole of 0.25mm then with high velocity ram machine at an end of small pieces, again in the Electroless copper in tinsel and hole, clean the back etches away a 0.15mm at the sheet avris far away in hole bonding jumper, adopt screen printing mask, photocuring then, blow the thick tin layer of weldering 0.3mm at the two ends of sheet hot blast again, can make the surface mount polymer thermistor device about zero power resistance 0.4 Ω, its ratio () of resistance value and its resistance value in the time of 20 ℃ in the time of 135 ℃ is not less than 10
5
Embodiment 14
Radiation mode changes electron beam irradiation into, and irradiation dose is identical with embodiment 13 respectively with other conditions, can obtain the 13 similar products with embodiment.
Embodiment 15~16
Mixing method is used extruder instead and is extruded, and the control of each section of extruder temperature is set at respectively:
150℃ 160℃ 170℃ 180℃
Other conditions are identical with embodiment 13~14 respectively, obtain the product similar to embodiment 13~14 respectively.
Embodiment 15~28
The sheet material irradiation that now is pressed into, then with the nickel sheet behind the surface coarsening after smooth, at pressure 5Mpa, be hot-pressed onto the two-sided of core under 180 ℃ of conditions of temperature, other condition is identical with embodiment 1~14, obtains the product similar to embodiment 1~14 respectively.