Macromolecular positive temperature coefficient thermosensitive resistor and manufacture method thereof
Technical field the present invention relates to a kind of thermistor and manufacture method thereof, more particularly, relates to a kind of macromolecular positive temperature coefficient thermosensitive resistor and manufacture method thereof.
Background technology is well-known, and usually, the crystallinity or the hemicrystalline polymer composite that are added with conducting particles can show positive temperature coefficient (PTC) characteristic: resistivity can increase fast with the rising of temperature in a relatively shorter temperature range.At room temperature, this quasi-resistance has lower resistance, when temperature rises to the macromolecule fusing point when above, is commonly referred to switch temperature TS, and resistivity begins fast rise.The added value of the maximum resistance of resistance value in the whole process is called PTC intensity under the room temperature.
In the prior art, thermistor has been widely used in the overcurrent protective device of circuit.Under the electric equipment normal operating conditions, the electric current in the circuit is less relatively, and thermistor temp is lower, and resistance is lower; Break down and work as circuit; as short circuit; overlap joint; when situations such as induction take place, produce big electric current in the circuit, during by thermistor; its temperature can raise suddenly and reach more than the switch temperature; cause the very big of its resistance value change, make circuit be in a kind of approximate open-circuit condition like this, thereby effectively protected other critical elements in the circuit.And after fault was got rid of, the temperature of thermistor descended, and its resistance value returns to low resistive state again.
Thermistor has been widely used in numerous areas such as telecommunication apparatus, battery of mobile phone, automotive electronics, Industry Control, household electrical appliance.In the prior art; the ptc characteristics that thermistor often occurs is poor; just PTC intensity is little; after temperature reaches switch temperature; it is enough big that its resistance value can not reach; circuit does not really reach a kind of approximate open-circuit condition, can not play enough effectively overcurrent protection, thereby use is restricted.
Summary of the invention the present invention aims to provide a kind of have high PTC intensity, thermistor and the manufacture method thereof concentrated more of resistance value at room temperature.
In order to achieve the above object, the invention provides following technical scheme: develop a kind of macromolecular positive temperature coefficient thermosensitive resistor, by macromolecule substrate and the pellet electrode that is compound in the substrate two sides, the insulating barrier formation that is welded in electrode surface lead-in wire shape electrode and is encapsulated in outer surface, it is characterized in that: the raw material composition and the parts by weight of substrate are as follows: polymer 40~65, conductive filler 30~60, processing aid 0.2~10, described polymer is homopolymers or copolymer, comprise polyethylene, polypropylene, the ethylene/propylene copolymer, the mixture of one or more arbitrary proportions of ethylene/acrylic acid copolymer and acrylate, described conductive filler is a nickel powder, copper powder, the mixture of one or more arbitrary proportions of carbon black or its analog, described processing aid is the mixture that comprises antioxidant and coupling agent, antioxidant: the weight ratio of coupling agent is 1: 1.5~2.5, wherein, antioxidant is acrylic acid alkoxide compound, and coupling agent is titanate esters or silane compound.In the above-mentioned raw materials proportioning, the addition ratio of conductive filler is important, adds in described ratio, and the substrate resistance rate can be controlled in the scope of 3-9 Ω .cm.The antioxidant that adds in described substrate can prevent polymer processing generation oxidation, and coupling agent can guarantee compatibility good between polymer and the filler.Described promoter addition should be controlled, if processing aid is too much, auxiliary agent easily produces residual in polymeric system, has influence on the electrical property of final products, adds very fewly, and then the compatibility between antioxygenic property difference or polymer and the filler is poor.
Also contain auxiliary composition inert filler 0~40 parts by weight in the raw material of the present invention's substrate, described inert filler is that the particle diameter of one or more arbitrary proportions of calcium oxide, zinc oxide, magnesium oxide, aluminium oxide, antimonous oxide, silicon dioxide, magnesium hydroxide, aluminium hydroxide or potter's clay is the mixture of 1~170 μ m.Owing to added inert filler in the system, improved the heat-resistant stability of material, help improving electrical property.If addition is too much, will cause the system poor processability, addition is very few, can not reach to improve thermal stability result.
Thermistor of the present invention, no matter whether contain inert filler, can also contain the crosslinking agent trihydroxy methyl propane trimethyl acrylate in the processing aid of 0.2~10 parts by weight, antioxidant: coupling agent: the weight ratio of crosslinking agent is 1: 1.5~2.5: 0.3~0.7.Add crosslinking agent and can improve the degree of cross linking of material, help electrical property, should control the addition of crosslinking agent, add too much, then easily produce residually in system, have influence on properties of product, addition is very few, can not reach the degree of cross linking of expection.
The manufacture method of thermistor of the present invention, manufacture process is as follows: (1) is for the first time mixing under 140 ℃~240 ℃ temperature with polymer, conductive filler and processing aid by metering, and compressing tablet becomes area 50~500cm
2The sheet material of thickness 0.5~2.5mm, with the electron beam or the Co60 cross-linking radiation of 2~10 Megarads, (2) with the sheet material fragmentation behind the irradiation then, and are for the second time mixing under 140 ℃~240 ℃ temperature, and compressing tablet becomes area 50~500cm
2The sheet material of thickness 0.5~2.5mm, (3) are compound to metal electrode by the mode of hot pressing two surfaces of sheet material again, obtain composite sheet, and with the electron beam or the Co60 cross-linking radiation of 20~60 Megarads, (4) are washed in small pieces, the welding lead-in wire shape electrode and seal insulating barrier at lead-in wire shape electrode outer surface with punch press at last, the thermistor finished product.
In concrete manufacture process, should be mixing with double screw extruder under 140 ℃~240 ℃ temperature, temperature control is quite important, low excessively as temperature, filler is difficult to fully be distributed in the polymeric system, and the too high then polymer of temperature easily produces degraded, influences the intensity of substrate; In addition, irradiation dose should be low at the electron beam or the Co60 cross-linking radiation irradiation dose of 10~60 Megarads, and polymer can not be full cross-linked, and irradiation dose height, polymer easily produce degraded.
Said method, no matter whether add auxiliary composition inert filler, no matter also in processing aid, whether also comprise the crosslinking agent trihydroxy methyl propane trimethyl acrylate, its method of operation and step are basic identical, if add auxiliary composition inert filler, then it is added with polymer, conductive filler, processing aid by metering, for the first time mixing under 140 ℃~240 ℃ temperature, compressing tablet becomes area 50~500cm
2The sheet material of thickness 0.5~2.5mm, with the electron beam or the Co60 cross-linking radiation of 2~10 Megarads, process and technology controlling and process are identical thereafter; If in processing aid, also add the crosslinking agent trihydroxy methyl propane trimethyl acrylate, no matter then whether add auxiliary composition inert filler again, all by measuring polymer, conductive filler and comprising the crosslinking agent trihydroxy methyl propane trimethyl acrylate at interior processing aid, if contain inert filler then add inert filler simultaneously, for the first time mixing under 140 ℃~240 ℃ temperature, compressing tablet becomes area 50~500cm
2The sheet material of thickness 0.5~2.5mm, with the electron beam or the Co60 cross-linking radiation of 2~10 Megarads, operating process thereafter and technology controlling and process are identical with preceding method, until obtaining the thermistor product.
The present invention with double screw extruder carry out for the first time mixing and for the second time mixing temperature be to be to outlet temperature by the double screw extruder import to increase progressively, controlling inlet temperature is 140 ℃~170 ℃, outlet temperature is 190 ℃~240 ℃.In the manufacture process, control inlet temperature and outlet temperature are convenient to operation.
Compared with prior art, the present invention has following tangible advantage: 1, adopted new mixing processing technology, manufacturing process is simple, is easy to control; 2, technique effect is good, owing to adopted the secondary mixing sweetening process, conductive filler and inert filler disperse homogeneous more in system, and system is through behind the cross-linking radiation, and cross-linked structure is also more even.3, good product quality: the substrate resistance rate can be controlled in the scope of 3-9 Ω .cm, because substrate microstructure stable homogeneous more, improved the electrical property of product: improved product P TC intensity, room temperature resistance value is also more concentrated.Product P TC intensity can reach 10
5, and room temperature resistance value is more concentrated, and the qualification rate of finished product reaches more than 85%; 4, be widely used: can be used for numerous areas such as telecommunication apparatus, Industry Control, household electrical appliance.
By specific embodiment the present invention is carried out more detailed description below the embodiment:
Embodiment 1 takes by weighing polymer-high density polyethylene (HDPE) 500 grams, electric conducting material-carbon black 350 grams, inert filler-calcium hydroxide granularity is 10 μ m, each 70 gram of 104 μ m, antioxidant-β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid 18 carbonic acid alcohol ester Irganox1076 are 10 grams, coupling agent-titanate esters 201 is 15 grams, crosslinking agent-trihydroxy methyl propane trimethyl acrylate 5 grams, above-mentioned each component is mixing even in double screw extruder, each section of extruder temperature is set at 160 ℃ 170 ℃ 180 ℃ 190 ℃ respectively, extrude, pulling-on piece is at pressure 6Mpa, under 185 ℃ of conditions of temperature, be hot pressed into area 130cm
2The sheet material of thickness 2.0mm is the electron beam irradiation of 4Mrad with dosage, and the sheet material behind the irradiation is extruded after fragmentation for the second time, pulling-on piece, and at pressure 6Mpa, under 185 ℃ of conditions of temperature, the hot pressing pulling-on piece becomes area 130cm
2The sheet material of thickness 2.0mm, at pressure 6Mpa, following single face roughening of the condition that temperature is 185 ℃ crossed nickel foil and is hot-pressed onto on the sheet material, with dosage is the 20Mrad electron beam irradiation, strike out 5 * 5 small pieces, weld the tinned wird of Φ 0.6mm then on the two sides respectively, seal the material package envelope with epoxy then.The zero power resistance that can make is the thermistor of 11 Ω.Resistance value percentage in the 10-12 scope is 89%.The resistance value ratio of resistance value at 20 ℃ the time is greater than 10 in the time of 135 ℃
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Embodiment 2 takes by weighing polymer-high density polyethylene (HDPE) 400 grams, electric conducting material-copper powder 200 grams, carbon black 350 grams, antioxidant-β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid 18 carbonic acid alcohol ester Irganox1076 are 1 gram, and coupling agent-titanate esters 201 is 1.5 grams, and above-mentioned each component is mixing even in double screw extruder, each section of extruder temperature is set at 160 ℃ 170 ℃ 180 ℃ 190 ℃ respectively, extrude, pulling-on piece is at pressure 6Mpa, under 185 ℃ of conditions of temperature, be hot pressed into area 60cm
2The sheet material of thickness 1.0mm is the Co60 irradiation of 2Mrad with dosage, and the sheet material behind the irradiation is extruded after fragmentation for the second time, pulling-on piece, and at pressure 6Mpa, under 185 ℃ of conditions of temperature, the hot pressing pulling-on piece becomes area 60cm
2The sheet material of thickness 1.0mm, at pressure 6Mpa, following single face roughening of the condition that temperature is 185 ℃ crossed nickel foil and is hot-pressed onto on the sheet material, with dosage is the Co60 electron beam irradiation of 30Mrad, strike out 5 * 5 small pieces, weld the tinned wird of Φ 0.6mm then on the two sides respectively, seal the material package envelope with epoxy then.The zero power resistance that can make is the thermistor of 11 Ω.Resistance value percentage in the 10-12 scope is 86%.The resistance value ratio of resistance value at 20 ℃ the time is greater than 10 in the time of 135 ℃
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Embodiment 3 takes by weighing polymer-low density polyethylene (LDPE) 400 grams, electric conducting material-nickel powder 300 grams, antioxidant-β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid 18 carbonic acid alcohol ester Irganox1076 are that 2 grams, coupling agent-titanate esters 201 are 5 grams, crosslinking agent-trihydroxy methyl propane trimethyl acrylate 1 gram, above-mentioned each component is mixing even in double screw extruder, each section of extruder temperature is set at 160 ℃ 170 ℃ 180 ℃ 190 ℃ respectively, extrude, pulling-on piece, at pressure 6Mpa, under 185 ℃ of conditions of temperature, be hot pressed into area 330cm
2The sheet material of thickness 2.5mm is the electron beam irradiation of 8Mrad with dosage, and the sheet material behind the irradiation is extruded after fragmentation for the second time, pulling-on piece, and at pressure 6Mpa, under 185 ℃ of conditions of temperature, the hot pressing pulling-on piece becomes area 330cm
2The sheet material of thickness 2.5mm, at pressure 6Mpa, following single face roughening of the condition that temperature is 185 ℃ crossed nickel foil and is hot-pressed onto on the sheet material, with dosage is the 85Mrad electron beam irradiation, strike out 5.5 * 5.5 small pieces, can make the thermistor that zero power resistance is 8.1 Ω, the percentage of resistance value in the scope of 7-9 Ω is 88%, and resistance value and the resistance value ratio in the time of 20 ℃ are greater than 10 in the time of 135 ℃
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Embodiment 4 takes by weighing polymer-ethylene/propene 400 grams, electric conducting material-carbon black 50 grams, carbon black 350 grams, inert filler-hydroxide particle-size is 10 μ m, each 80 gram of 104 μ m, the silicon dioxide granularity is 10 μ m, each 100 gram of 104 μ m, antioxidant-β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid 18 carbonic acid alcohol ester Irganox1076 are 5 grams, coupling agent-titanate esters 201 is 12 grams, above-mentioned each component is mixing even in double screw extruder, and each section of extruder temperature is set at 160 ℃ 170 ℃ 180 ℃ 190 ℃ respectively, extrudes, pulling-on piece, at pressure 6Mpa, under 185 ℃ of conditions of temperature, be hot pressed into area 100cm
2The sheet material of thickness 2.0mm is the Co60 irradiation of 10Mrad with dosage, and the sheet material behind the irradiation is extruded after fragmentation for the second time, pulling-on piece, and at pressure 6Mpa, under 185 ℃ of conditions of temperature, the hot pressing pulling-on piece becomes area 100cm
2The sheet material of thickness 2.0mm, at pressure 6Mpa, following single face roughening of the condition that temperature is 185 ℃ crossed nickel foil and is hot-pressed onto on the sheet material, with dosage is the Co60 irradiation of 50Mrad, strike out 5.5 * 5.5 small pieces, can make the thermistor that zero power resistance is 7.7 Ω, the percentage of resistance value in the scope of 7-9 Ω is 88%, and resistance value and the resistance value ratio in the time of 20 ℃ are greater than 10 in the time of 135 ℃
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Embodiment 5 takes by weighing polymer-acrylate 500 grams, electric conducting material-carbon black 350 grams, inert filler-zinc oxide granularity is 10 μ m, each 30 gram of 104 μ m, potter's clay 250 grams, antioxidant-β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid 18 carbonic acid alcohol ester Irganox1076 are 15 grams, coupling agent-titanate esters 201 is 25 grams, crosslinking agent-trihydroxy methyl propane trimethyl acrylate 10 grams, above-mentioned each component is mixing even in double screw extruder, and each section of extruder temperature is set at 160 ℃ 170 ℃ 180 ℃ 190 ℃ respectively, extrudes, pulling-on piece, at pressure 6Mpa, under 185 ℃ of conditions of temperature, be hot pressed into area 130cm
2The sheet material of thickness 2.0mm is the electron beam irradiation of 4Mrad with dosage, and the sheet material behind the irradiation is extruded after fragmentation for the second time, pulling-on piece, and at pressure 6Mpa, under 185 ℃ of conditions of temperature, the hot pressing pulling-on piece becomes area 150cm
2The sheet material of thickness 2.0mm, at pressure 6Mpa, following single face roughening of the condition that temperature is 185 ℃ crossed nickel foil and is hot-pressed onto on the sheet material, with dosage is the 20Mrad electron beam irradiation, strike out 5.5 * 5.5 small pieces, can make the thermistor that zero power resistance is 7.9 Ω, the percentage of resistance value in the scope of 7-9 Ω is 90%, and resistance value and the resistance value ratio in the time of 20 ℃ are greater than 10 in the time of 135 ℃
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