Macromolecule-based conductive composite material and PTC element

Abstract

A macromolecule-based conductive composite material and a PTC element. The macromolecule-based conductive composite material comprises: a macromolecule base material, having a volume fraction of the macromolecule base material of 20%-75%; a conductive filler with a core-shell granule structure and dispersed in the macromolecule base material, having a volume fraction of 25%-80%; and a coupling agent, being a titanate coupling agent and accounting for 0%-5% of the volume of the conductive filler. The PTC element prepared by using the macromolecule-based conductive composite material comprises at least two metal electrode plates (12, 12), a macromolecule-based conductive composite material (11) being closely combined with the metal electrode plates (12, 12). The PTC element prepared from the macromolecule-based conductive composite material has the advantages of low room-temperature resistivity, outstanding weather durability, good voltage resistance and good resistor repeatability.

Claims

1. A conductive composite material, comprising: a polymer bases material; and a conductive filler, wherein the polymer base material is selected from the group consisting of polyethylene, polypropylene, polyvinylidene difluoride, polyolefin elastomer, epoxy resin, ethylene-vinyl acetate copolymer, polymethylmethacrylate, ethylene-acrylic acid copolymer and a mixture thereof, the conductive filler comprises core-shell particles having a core made of a core material and a shell made of a shell material different from the core material wherein the polymer base material account for 20%70% of volume fraction in the conductive composite material; and the conductive filler accounts for 25%80% of volume fraction of the conductive composite material; and the core material is selected from the group comprising of tantalum, zirconium, titanium, niobium, molybdenum, hafnium, tungsten, chromium and beryllium, and the shell material is selected from boride, nitride, carbide or silicide of the core material.

2. The conductive composite material according to claim 1, wherein the core-shell particles further comprise an interlayer, wherein the interlayer is made of boride, nitride, carbide or suicide of the core material, but different from the shell material.

3. The conductive composite material according to claim 1, wherein the boride, is one of tantalum boride, tantalum diboride, vanadium boride, vanadium diboride, zirconium diboride, titanium diboride, niobium boride, niobium diboride, molybdenum boride (Mo.sub.2B), molybdenum pentaboride (Mo.sub.2B.sub.5), hafnium diboride, tungsten boride, ditungsten boride, chromium boride, dichromium boride(Cr.sub.2B), chromium diboride and chromium triboride (Cr.sub.5B.sub.3).

4. The conductive composite material according to claim 1, wherein the nitride is one of tantalum nitride, vanadium nitride, zirconium nitride, titanium nitride, niobium nitride and hafnium nitride.

5. The conductive composite material according to claim 1, wherein, the carbide is one of tantalum carbide, vanadium carbide, zirconium carbide, titanium carbide, niobium carbide, molybdenum carbide (Mo.sub.2C), hafnium carbide, tungsten monocarbide, ditungsten carbide and trichromium dicarbide (Cr.sub.3C.sub.2).

6. The conductive composite material according to claim 1, wherein the silicide is one of tantalum disilicide, tantalum silicide (Ta.sub.5Si.sub.3), trivanadium silicide, vanadium disilicide, zirconium disilicide, titanium disilicde, titanium silicide(Ti.sub.5Si.sub.3), niobium disilieide, molybdenum disilicide, hafnium disilicide, tungsten disilicide, trichromium silicide(Cr.sub.3Si) and chromium disilicide.

7. The conductive composite material according to claim 1, further comprising: a coupling agent, wherein the coupling agent comprises one or more mixtures of titanate coupling agent, single-type alkoxy titanate coupling agent, single alkoxy pyrophosphate titanate coupling agent, chelate-type titanate coupling agent, coordination-type titanate coupling agent and quaternary ammonium salt type titanate coupling agent, and wherein the coupling agent accounts for 0.05%5% of the volume of conductive filler, and wherein the volume conductivity of the conductive filler is less than 0.01 m.

8. The conductive composite material according to claim 1, further comprising one or more of antioxidant agent, radiation cross-linking agent, dispersing agent, stabilizing agent, non-conductive filler, combustion resistant, and arc inhibitor.

9. The conductive composite material according to claim 8, wherein the non-conductive filler comprises one or both of magnesium hydroxide and calcium carbonate.

10. A positive thermal coefficient (PTC) element comprising: a first electrode plate; a second electrode plate spaced from the first electrode plate; and a material layer disposed between the first electrode plate and the second electrode plate, wherein the material layer comprises the conductive composite material according to claim 1.

11. The PTC element according to claim 10, wherein the material layer has a thickness between 0.01 to 3.0 mm.

12. The PTC element according to claim 10, wherein the first electrode plate and the second electrode plate each is made of one of nickel, copper, aluminum, zinc and a compound thereof.

13. A method of producing a positive thermal coefficient (PTC) element, comprising: mixing a polymer based material, and a conductive filler at a temperature higher than a melting temperature of the polymer based material for providing a mixed material in a melting state; shaping the mixed material in the melting state into a layer, the layer has a first side and a second side; and pressing a first electrode plate on the first side of the layer and pressing a second electrode layer on the second side of the layer while the mixed material is in the melting state; wherein the polymer based material is selected from the group consisting of polyethylene, polypropylene, polyvinylidene difluoride, polyolefin elastomer, epoxy resin, ethylene-vinyl acetate copolymer, polymethylmethacrylate, ethylene-acrylic acid copolymer and a mixture thereof, the conductive filler comprises core-shell particles having a core made of a core material and a shell made of a shell material different from the core material; and the core material is selected from the group comprising of tantalum, zirconium, titanium, niobium, molybdenum, hafnium, tungsten, chromium and beryllium, and the shell material is selected from boride, nitride, carbide or silicide of the core material.

14. The method according to claim 13, wherein said mixing comprises adding a coupling agent with the polymer based material and the conductive filler for providing the mixed material, the coupling agent comprising one or more mixtures of titanate coupling agent, single-type alkoxy titanate coupling agent, single alkoxy pyrophosphate titanate coupling agent, chelate-type titanate coupling agent, coordination-type titanate coupling agent and quaternary ammonium salt type titanate coupling agent, and wherein the polymer based material accounts for 20%75% of volume fraction in the conductive composite material; the conductive filler accounts for 25%80% of volume fraction of the conductive composite material; and the coupling agent accounts for 0.05%5% of the volume of conductive filler.

15. The method according to claim 13, wherein the boride is one of tantalum boride, tantalum diboride, vanadium boride, vanadium diboride, zirconium diboride, titanium diboride, niobium boride, niobium diboride, molybdenum boride (Mo.sub.2B), molybdenum pentaboride((Mo.sub.2B.sub.5), hafnium diboride, tungsten boride, ditungsten boride, chromium boride, dichromium boride(Cr.sub.2B), chromium diboride and chromium triboride(Cr.sub.5B.sub.3).

16. The method according to claim 13, wherein the nitride is one of tantalum nitride, vanadium nitride, zirconium nitride, titanium nitride, niobium nitride and hafnium nitride.

17. The method according to claim 13, wherein the carbide is one of tantalum carbide, vanadium carbide, zirconium carbide, titanium carbide, niobium carbide, molybdenum carbide (Mo.sub.2C), hafnium carbide, tungsten monocarbide, ditungsten carbide and trichromium dicarbide (Cr.sub.3C.sub.2).

18. The method according to claim 13, wherein the silicide is one of tantalum disilicide, tantalum silicide (Ta.sub.5Si.sub.3), trivanadium silicide, vanadium disilicide, zirconium disilicide, titanium disiliede, titanium silicide(Ti.sub.5Si.sub.3), niobium disilicide, molybdenum disilicide, hafnium disilicide, tungsten disilicide, trichromium silicide(Cr.sub.3Si) and chromium disilicide.

Description

ILLUSTRATION

(1) FIG. 1 is the structure schematic of the invented PTC components.

(2) FIG. 2 is the structure schematic of the invented PTC components implementations.

(3) FIG. 3 is the resistance-temperature graph of the thermistor components of the implementation NO. 6.

NO. EXPLANATION IN THE DRAWING

(4) 11Macromolecule Based Conductive Composite Materials; 12, 12metal electrode slices; 13, 13metal conductive components.
Concrete Implementing Ways

(5) Implementation No. 16 is the material mentioned in the invention with coupling agent

(6) Implementation No. 1

(7) The conductive composite materials for producing PTC parts include:

(8) (a) Macromolecule Based Material is High-density polyethylene, and the melting temperature is 134 C., density is 0.953 g/cm.sup.3, volume fraction is 40%;

(9) (b) The conductive filer is with the core-shell particles structure, and consists of the core, shell and interlayer. The shell is W2B, the interlayer is WB, and the core is metal tungsten. It's grain size is 2.0 um, and the volume fraction is 60%.

(10) (c) Coupling agent is single alcoxyl based isopropyl di-oleic acid acyloxy titanate, the volume fraction accounts for the 0.5% of the volume in conductive filler, and the density is 0.976 g/cm.sup.3.

(11) Setting the internal mixer temperature at 180 C., speed at 30 rotation per minute, putting the polymer in it for mixing 3 minutes, and then adding the conductive filler to go on mixing 15 minutes, finally the Macromolecule Based Conductive Composite Material will be finished. The melted and mixed Macromolecule Based Conductive Composite Material was flattened by mill, and the Macromolecule Based Conductive Composite Material 11 with the thickness 0.20.25 mm is done.

(12) The production process of PTC components is as below:

(13) PIs refer to the drawing 1 (sketch of the PTC components mentioned in the invention), let's put the Macromolecule Based Conductive Composite Material 11 in the middle of the two symmetric metal electrode slices 12 and 12, then the metal electrode slices 12 and 12 will be tightly connected with the Macromolecule Based Conductive Composite Material through thermo compression bonding. The temperature of thermo compression bonding will be set at 180 C., at first to warm up 5 minutes, and next to hot press the materials 3 minutes with the press 5 MPa, then cold press it 8 minutes in the cold press machine, after that punching it into single component with 3*4 mm boy mould, at last jointing the two metal pins 13 and 13 on the surface of metal electrode slices 12 and 12, the PTC components are produced.

(14) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(15) Implementation No. 2

(16) The steps of producing Macromolecule Based Conductive Composite Material and PTC components are the same with the implementation No. 1, but the proportion of the volume fraction of the coupling agent that in the conductive composite material is changed from 0.5% of the volume in the conductive filler to 1.0%.

(17) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(18) Implementation No. 3

(19) The steps of producing Macromolecule Based Conductive Composite Material and PTC components are the same with the implementation No. 1, but the proportion of the volume fraction of the coupling agent that in the conductive composite material is changed from 0.5% of the volume in the conductive filler to 1.5%.

(20) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(21) Implementation No. 4

(22) The steps of producing Macromolecule Based Conductive Composite Material and PTC components are the same with the implementation No. 1, but the proportion of the volume fraction of the coupling agent that in the conductive composite material is changed from 0.5% of the volume in the conductive filler to 2.0%.

(23) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(24) Implementation No. 5

(25) The steps of producing Macromolecule Based Conductive Composite Material and PTC components are the same with the implementation No. 1, but the proportion of the volume fraction of the coupling agent that in the conductive composite material is changed from 0.5% of the volume in the conductive filler to 2.5%.

(26) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(27) Implementation No. 6

(28) The steps of producing Macromolecule Based Conductive Composite Material and PTC components are the same with the implementation No. 2, but the used coupling agent is single alkoxy style isopropyl tri-oleic acid acyloxy titanate, and the additive amount accounts for 1.0% of the volume in conductive filler, density is 1.01 g/cm.sup.3.

(29) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(30) Comparison No. 1

(31) The steps of producing Macromolecule Based Conductive Composite Material and PTC components are the same with the implementation No. 3, but the Macromolecule Based Conductive Composite Material is without any coupling agent.

(32) The electrical property of the PTC components in the implementation is as the attached chart No. 1.

(33) The R.sub.min in the table 1 means the resistance after soldering two metal pins 13 and 13 on the surface of the two metal electrode slices 12 and 12, which is the minimum resistance of 10 pcs PTC components;

(34) R.sub.average means the resistance after soldering two metal pins 13 and 13 on the surface of the two metal electrode slices 12 and 12, which is the average value of 10 pcs PTC components;

(35) R.sub.max means the resistance after soldering two metal pins 13 and 13 on the surface of the two metal electrode slices 12 and 12, which is the max value of 10 pcs PTC components.

(36) STDEV means the standard deviation of 10 pcs PTC components, which reflected the discreteness of resistance.

(37) R1 means the resistance that is tested on the condition that PTC components are electrified (6V/50 A) 6 seconds and then be placed at the temperature 25 C. for an hour.

(38) R.sub.100 means the resistance that is tested on the condition that PTC components be electrified (6V/50 A) 6 seconds, then be cut off the power 60 seconds, keeping the cycle 100 times, finally be placed at the temperature 25 C. for an hour.

(39) R.sub.100cycles means the resistance that is tested on the condition that PTC components are put at the temperature of +85 C. for 30 minutes, and then be put at the temperature of 40 C. for 30 minutes, keeping the cycle 100 times, finally be placed at the temperature of 25 C. for an hour.

(40) R.sub.6V/50 A means the resistance that is tested on the condition that the PTC components withstand voltage for 2 hours under 6V, 50 A, then be placed at the temperature 25 C. for an hour.

(41) R.sub.12v/50a means the resistance that is tested on the condition that the PTC components withstand voltage for 2 hours under 12V, 50 A, then be placed at the temperature 25 C. for an hour.

(42) TABLE-US-00001 TABLE 1 Implementation/ Implement- Implement- Implement- Implement- Implement- Implement- Comparison Comparison ation 1 ation 2 ation 3 ation 4 ation 5 ation 6 1 Concentrition R.sub.min 5.4 5.6 5.5 6.1 6.6 6.8 7.2 of resistance (mohm) R.sub.average 6.6 6.5 6.0 6.7 7.0 7.6 8.4 (mohm) R.sub.max 7.2 7.0 6.6 7.4 8.0 8.3 9.7 (mohm) STDEV 0.5 0.5 0.4 0.4 0.5 0.7 0.9 Current R.sub.1 7.6 7.8 7.2 7.6 7.9 8.8 9.6 resistance R.sub.100 18.3 18.6 16.7 19.5 20.4 22.3 27.8 Weatherability Heat cycle 8.5 8.4 8.0 8.2 9.1 9.6 10.7 R.sub.100 cycles (mohm) Pressure R.sub.6V/50A 16.0 15.6 14.6 17.2 17.8 18.5 20.4 resistance (mohm) R.sub.l2V/50A 18.6 19.0 18.8 20.1 22.4 24.1 Breakdown (mohm) Processability Torque 45.3 42.5 40.4 42.6 44.1 46.2 44.8 (N .Math. m)

(43) From the table 1 we can see that the implementation 16 has the same volume fraction of crystalline polymer and conductive filler with the comparison, but the implementation 16 is added coupling agent, and the resistance of finished products is lower than the one without it. What's more the added one is with a lower discreteness, which means the coupling agent can help the conductive material to disperse in the polymer matrix. In the implementation 3, when it's with the same volume fraction of conductive filler, and the volume fraction of coupling agent comes to 1.5%, the PTC components are with the lowest resistance. The PTC components in Implementation 16 and in comparison 1 both can withstand the voltage of 6V, but the PTC components in implementation 16 can withstand the voltage of 12V, the one in the comparison can't, which means coupling agent can increase the pressure resistance of PTC components. The torque at the time of processing the Macromolecule Based Conductive Composite Materials showed us that the implementation 16 with a certain of coupling agent has a lower torque proportion than those without coupling agent, which means coupling agent can improve the shaping and processing ability of Macromolecule Based Conductive Composite Material.

(44) In the implement 16, the conductive composite material that used by the PTC parts added the coupling agent that can improve the disperse state of conductive filler and can strengthen the conductive network of the composite material, thus the PTC parts have higher concentration of resistance. What's more, the conductive filler with core-shell structure is not easy to be oxidized, and needn't to protect the Macromolecule Based Conductive Composite Material by packing, thus the small size PTC components with the thickness 0.2 mm2.0 mm and the current carrying area 1210, 1206, 0805, 0603 can be produced.

(45) The below implements are without coupling agent, formula and performance will be showed in table 2.

(46) Implement No. 7

(47) The formula of Macromolecule Based Conductive Composite Material that for producing thermistor components is showed as table 2. In it, polymer 1 is high density polyethylene, it's melting temperature is at 134 C., density is 0.953 g/cm.sup.3; conductive filler 1 is titanium carbide, its' Fisher particle size is 2.0 um, density id 1.93 g cm.sup.3; conductive filler 2 is with core-shell structure, its' size is 2.0 um, the shell is W2B, the interlayer is WB, and the core is metal tungsten.

(48) The productive processes of thermistor components are as below: Setting the internal mixer temperature at 180 C., speed at 30 rotation per minute, putting the polymer in it for mixing 3 minutes, and then adding the conductive filler to go on mixing 15 minutes, finally the Macromolecule Based Conductive Composite Material will be finished. The melted and mixed Macromolecule Based Conductive Composite Material was flattened by mill, and the Macromolecule Based Conductive Composite Material 11 with the thickness 0.20.25 mm is done.

(49) The thermistor components mentioned in the invention are as drawing 1. Let's put the Macromolecule Based Conductive Composite Material 11 in the middle of the two symmetric metal electrode slices 12 and 12, then the metal electrode slices 12 and 12 will be tightly connected with the Macromolecule Based Conductive Composite Material through thermo compression bonding. The temperature of thermo compression bonding will be set at 180 C., at first to warm up 5 minutes, and next to hot press the materials 3 minutes with the press 5 MPa, then cold press it 8 minutes in the cold press machine, after that punching it into single component with 3*4 mm boy mould, at last jointing the two metal pins 13 and 13 on the surface of metal electrode slices 12 and 12, the PTC components are produced.

(50) Table 3 is the resistance-temperature graph of thermistor components in the implement. The resistance of thermistor components will be very low when it's at the temperature of 25 C., and the resistance will be higher an higher with the increasing of temperature. When temperature increases to 130 C. or so, the resistance of thermistor components will change suddenly, and increases about 10 order of magnitude. At this time, the thermistor components will change from conductor to insulator so that the circuit will be turn off to protect the circuit components.

(51) Implement No. 8

(52) The composition of Macromolecule Based Conductive Composite Material for producing thermistor components is the same with implement 7, and the formula of Macromolecule Based Conductive Composite Material and the electrical specification of thermistor components are as table 2, but the steps for producing Macromolecule Based Conductive Composite Material sheet and thermistor components are different. The steps are as below:

(53) After flouring the polymer, put the flour into mixer to dry mix with conductive filler for 30 minutes, and then add the mixture into twin-screw extruder, after melting and mixing at the temperature of 180 C.220 C., the mixture will be squeezed out and be granulated, then the granules of Macromolecule Based Conductive Composite Material are formed. The granules will be added into another twin-screw extruder, at the temperature of 180 C.220 C., it will be squeezed out by extruder die head and turn into fused Macromolecule Based Conductive Composite Material sheet 11. The sheet 11 will be tightly connected with the upper and lower two symmetric metal electrode slices 12 and 12 through hot pressing by hot press roller. After that, the sheet will be cut into the core material with size 110*200 mm, and then the core material will be punched into single components with size 3*4 mm by modules, at last the two metal pins 14 and 15 will be soldered on the surface of upper and lower metal electrode slices 12 and 12 by reflow soldering to form the thermstor components.

(54) Implement No. 9

(55) The composition of Macromolecule Based Conductive Composite Material for producing thermistor components is the same with implement 7, and the formula of Macromolecule Based Conductive Composite Material and the electrical specification of thermistor components are as table 2, but the volume fraction of polymer 1 will be changed from 34% to 38%, and the volume fraction of conductive filler 2 will be changed from 60% to 56%.

(56) Implementation No. 10

(57) The composition of Macromolecule Based Conductive Composite Material for producing thermistor components is the same with implement 7, and the formula of Macromolecule Based Conductive Composite Material and the electrical specification of thermistor components are as table 2, but the volume fraction of polymer 1 will be changed from 34% to 38%, the volume fraction of polymer 2 will be changed from 6% to 10%, and the volume fraction of conductive filler 2 will be changed from 60% to 56%.

(58) Comparison 2

(59) The formula of Macromolecule Based Conductive Composite Material and the electrical specification of thermistor components are as table 2, and the steps on producing Macromolecule Based Conductive Composite Material and over current protection components are the same with the implementation 1, but the conductive filler 2 will turned to conductive filler 1.

(60) Comparison 3

(61) the formula of Macromolecule Based Conductive Composite Material and the electrical specification of thermistor components are as table 2, and the steps on producing Macromolecule Based Conductive Composite Material and over current protection components are the same with the implementation 1, but the conductive filler 2 will turned to conductive filler 1, the volume fraction of polymer 1 will be changed from 34% to 38%, and the volume fraction of conductive filler will be changed from 60% to 56%.

(62) Comparison 4

(63) the formula of Macromolecule Based Conductive Composite Material and the electrical specification of thermistor components are as table 2, and the steps on producing Macromolecule Based Conductive Composite Material and over current protection components are the same with the implementation 1, but the conductive filler 2 will turned to conductive filler 1, the volume fraction of polymer 1 will be changed from 34% to 38%, the volume fraction of polymer 2 will be increased from 6% to 10%, and the volume fraction of conductive filler will be changed from 60% to 52%. In it, the resistance of thermistor components is measured by four-probe method.

(64) Results analysis: the resistance data in the table 2 are tested on the condition that the thermistor components that is made from the Macromolecule Based Conductive Composite Material mentioned in the invention are placed at the temperature of 25 C. for an hour after triggering in the condition of 6V/50 A.

(65) The R in the table 2 means the resistance of thermistor components' two metal electrode slices 12 and 12 before being soldered the two metal pins 13 and 13 on their surfaces; R.sub.0 means the resistance of thermistor components' two metal electrode slices 12 and 12 after being soldered the two metal pins 13 and 13 on their surfaces; R.sub.1 means the resistance that is tested on the condition that PTC components are electrified (6V/50 A) 6 seconds and then be placed at the temperature of 25 C. for an hour. R.sub.25 means the resistance that is tested on the condition that PTC components be electrified (6V/50 A) 6 seconds, then be cut off the power 60 seconds, and keep the cycle 25 times, finally be placed at the temperature 25 C. for an hour. R.sub.50 means the resistance that is tested on the condition that PTC components be electrified (6V/50 A) 6 seconds, then be cut off the power 60 seconds, and keep the cycle 50 times, finally be placed at the temperature 25 C. for an hour. R.sub.100 means the resistance that is tested on the condition that PTC components be electrified (6V/50 A) 6 seconds, then be cut off the power 60 seconds, and keep the cycle 100 times, finally be placed at the temperature 25 C. for an hour. R.sub.100cycles means the resistance that is tested on the condition that PTC components are put at the temperature of +85 C. for 30 minutes, and then be put at the temperature of 40 C. for 30 minutes, and keep the cycle 100 times, finally be placed at the temperature of 25 C. for an hour. (High temperature and humidity) R.sub.1000h means the resistance that is tested on the condition that PTC components are put in the environment of 85 C., 85% RH for 1000 hours and then be placed at the temperature of 25 C. for an hour. (High humidity) R.sub.1000h means the resistance that is tested on the condition that PTC components are put in the environment of 60 C., 95% RH for 1000 hours and then be placed at the temperature of 25 C. for an hour. Regarding the press resistance, 6V/50 A2H means the thermistor components withstand voltage for 2 hours in the condition of 6V, 50 A; 12V/50 A/2H means the thermistor components withstand voltage for 2 hours in the condition of 12V, 50 A; Pressure resistance is OK means the over current protection components do not burn and crack, NG means thermistor components burn or crack.

(66) TABLE-US-00002 TABLE 2 Implementation/ Implement- Implement- Implement- Implement- Comparison Comparison Comparison Comparison ation 7 ation 8 ation 9 ation 10 2 3 4 Composition (Volume percent) (%) Polymer 1 34 34 38 38 34 38 38 Polymer 2 6 6 6 10 6 6 10 Conductivity 60 56 52 filler 1 Conductivity 60 60 56 52 filler 2 Electrical characteristic R (mohm) 1.0 0.8 1.1 1.5 1.6 2.1 2.5 R.sub.0 (mohm) 5.0 4.5 5.4 5.7 6.2 6.7 7.5 R.sub.1 (mohm) 5.9 4.8 6.0 6.5 8.7 9.1 9.7 R.sub.25 (mohm) 9.5 6.8 9.8 10.4 12.5 13.6 14.8 R.sub.50 (mohm) 12.8 9.7 13.2 14.5 17.6 17.8 18.9 R.sub.100 (mohm) 17.5 13.1 18.6 20.1 24.3 27.7 31.3 Weather durability heat cycle 8.5 6.0 12.0 12.8 18.7 20.6 24.7 R.sub.100 cycles (mohm) High temperature 7.8 6.6 8.6 9.2 9.4 7.3 8.5 and humidity R.sub.1000 h (mohm) High humidity 7.2 6.0 7.9 8.6 7.8 8.2 8.6 R.sub.1000 h (mohm) Pressure resistance 6 V/50 A/2 h OK OK OK OK OK OK OK 12 V/50 A/2 h OK OK OK OK NG NG NG

(67) From table 2 we can see: implementation 78 and comparison 2; implementation 9 and comparison 3; implementation 10 and comparison 4, each of the group has the same volume fraction of conductive filler, but the conductive filler used in the implementation 710 is with the core-shell granule structure, the resistance of finished products that are made from this kind of filler is lower than the resistance of products with the conductive filler that is not core-shell granule structure but titanium carbide used in the implementation 24. The resistance tested in the implementation 710 is lower than the resistance tested in the implementation 24 after the thermistor components being punch 100 times by the current of 6V/50 A, which showed the good resistor repeatability.

(68) The thermistor components in Implementation 710 and in comparison 24 all can withstand the voltage of 6V, but the thermistor components in implementation 710 can withstand the voltage of 12V, the one in the comparison 24 can't, which means that the thermistor components produced by the conductive filler with core-shell structure has good pressure resistance. From table 3 we can see that the thermistor components produced by the conductive filler with core-shell structure has good PTC strength (the mentioned PTC strength is the logarithm values of the max resistivity of samples in the resistivity-temperature graph and the resistivity of samples at the room temperature).

(69) The thermistore components mentioned in the implementation 710 has low room-temperature resistivity, outstanding weather durability, good voltage resistance, excellent resistor repeatability and PTC strength, because it used the Macromolecule Based Conductive Composite Material that contained the core-shell structural conductive filler with low resistivity. What's more, the conductive filler with core-shell structure is hard to be oxidized, and needn't to protect the Macromolecule Based Conductive Composite Material by packing, thus the small size PTC components with the thickness 0.2 mm2.0 mm and the current carrying area 1210, 1206, 0805, 0603 can be produced.

(70) The invention's characteristics and contents are explained as above, but the explanation is still limited or just refers to some particular part, the invention's characteristic maybe will more than the contents that are mentioned in the paper. Thus the invention's protective range will not be limited in the contents of the implementation part, but should includes the combination of all the contents that showed in different part, and the various of replacement and embellishment that accord with the invention, which is covered by claims of the invention.