CN102167859B - Low-resistivity polymer positive temperature coefficient material and preparation method thereof - Google Patents
Low-resistivity polymer positive temperature coefficient material and preparation method thereof Download PDFInfo
- Publication number
- CN102167859B CN102167859B CN 201110021957 CN201110021957A CN102167859B CN 102167859 B CN102167859 B CN 102167859B CN 201110021957 CN201110021957 CN 201110021957 CN 201110021957 A CN201110021957 A CN 201110021957A CN 102167859 B CN102167859 B CN 102167859B
- Authority
- CN
- China
- Prior art keywords
- carbon black
- low
- resistivity
- ptc
- matrix material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The invention provides a low room temperature resistivity polymer positive temperature coefficient (PTC) material and a preparation method thereof. The material consists of polyethylene, carbon black and graphite fiber, wherein the ratio of carbon black to polyethylene is the composition ratio of the carbon black/polyethylene binary system after percolation change; and the dosage ratio of graphite fiber to polyethylene is lower than the composition ratio of the binary system at the beginning of percolation change. The three components can be combined through melting and mixing. The PTC composite material prepared by the method has low room temperature resistivity and high PTC strength. Meanwhile, the method is simple and environmentally friendly. The polymer PTC material can be used to prepare circuit-protecting elements for the overcurrent and overheat protections of the circuit.
Description
Technical field
The present invention relates to a kind of composite conducting polymer material and preparation method thereof, be specifically related to a kind of composite conducting polymer material and preparation method thereof with low room temperature resistivity and high PTC intensity with PTC (PTC) effect.
Background technology
As everyone knows, the composite conducting polymer material with positive temperature coefficient effect (PTC effect, near the variation that resistance raises and increases, some orders of magnitude take place a certain temperature with temperature) can be used for making electric device, like circuit brake.This type matrix material comprises a kind of polymeric constituent and is dispersed in granular conductive filler material wherein, like carbon black and metal.This type properties of materials can use room temperature resistivity and two parameters of PTC intensity (resistance value after resistance sharply increases and the ratio of room temperature resistance value) to describe.The ptc polymer that is applicable to circuit brake requires to have lower room temperature resistivity and high PTC intensity, and for example room temperature resistivity is lower than 100 Ω .cm, and PTC intensity is higher than 1000 times.
Composite conducting polymer material with PTC effect is applicable to temperature and electric current is changed the circuit brake of making response.Under normal circumstances, in circuit, remain on low temperature and low resistance state with the placed in-line circuit brake of load.But, flow to the electric current in the load thereby effectively cut off when circuit is in overheated or during overcurrent condition, the resistance of this device just raises.For many application, hope that the resistance of this device is low as far as possible, so that it minimizes in the influence of normal work period to circuit resistance.Though the low-resistance device can be processed through varying sized method, for example, make interelectrode distance very little or make the area of device very big, preferred gadget is because they take up space less on circuit card and generally have the ideal thermal property.Realize that the prevailing technology of gadget is to adopt the composite conducting polymer material with low-resistivity.
The resistivity of composite conducting polymer material can reduce through adding more conductive filler material, but adds the processing characteristics that more conductive filler material can influence mixture, because system viscosity increases.And, add more conductive filler material after, the PTC intensity of mixture can reduce.Select for use the electroconductibility good metal can reduce the room temperature resistivity of matrix material as conductive filler material.The Chinese patent publication number is CN1993778, and the patent of invention that name is called polymer PTC device discloses the ptc polymer that can prepare low-resistivity with metal or alloy as conductive filler material.But filler preparation technology is loaded down with trivial details, and the PTC intensity of material is very low, is merely 10
4, particularly, in the life-time service process, because the oxidation of metal, the room temperature resistivity of matrix material will increase.Someone has carried out granulous carbon black and fibrous conductive filler material are used the trial with preparation low-resistivity polymer PTC matrix material.Su Chang (electrically conductive polyaniline nano fiber is to the influence of Vilaterm carbon black compound system resistance behavior. polymer material science and engineering .2009,25 (2): 77) reported in ptc polymer polyethylene/carbon ink system commonly used and add polyaniline nano fiber.Because the volume specific resistance of polyaniline nano fiber is higher, the matrix material volume resistivity of preparation is minimum to be 5250 Ω .cm.Reference (Effects of the addition of multi-walled carbon nanotubes on the positivetemperature coefficient characteristics of carbon black filled high polyethylenenanocomposites.Scripta materials; 2006,55:1119) reported carbon nanotube has been added the polyethylene/carbon ink system to improve the electrical conductive behavior of matrix material.Although the prepared composite material has high PTC intensity, reach 10
7, but the room temperature resistivity of matrix material is higher than 100 Ω .cm.And, in the Composite Preparation process, need to adopt complicated carbon nano tube surface treatment process and harmful solvent.In the material component proportion design, what take in the document is a fixing earlier component concentration such as content of carbon black or matrix content, adjusts two other component concentration again, is difficult to find the best of ternary system to be formed by this method.
Summary of the invention
The purpose of this invention is to provide and a kind ofly have low room temperature resistivity, high PTC intensity, and method of manufacture is easy, the ptc polymer of environmental protection.
The technical scheme that the present invention proposes is not to adjust the proportioning of component simply, but is that formulating of recipe is carried out on the basis with ptc polymer PTC effector mechanism.In the matrix material of being made up of carbon black and Vilaterm, along with the increase of conductive filler material content, the variation of matrix material volume resistivity has to exceed oozes characteristic.When filler content was lower than excess effusion value, the resistivity of matrix material increased and slowly reduces with filler content, but material still is in state of insulation; When filler content reached a certain numerical value, along with filler content further increases, the volume specific resistance of matrix material sharply reduced, and in not too big filler content scope, matrix material becomes conduction state by state of insulation; When filler content continued to increase, the volume specific resistance of matrix material slowly reduced again.When filler content is lower than excess effusion value, do not set up conductive network in the matrix material as yet; And the process of percolation transition also is that conductive network is by lacking the process of setting up; When filler content was higher than excess effusion value, the conductive network of matrix material was further perfect.Because temperature raises during volumetric expansion, conductive network wherein will wreck when matrices of composite material.The fragility of conductive network also is different in the filler content different composite materials.It is more responsive to volumetric expansion that filler content is in the conductive network of matrix material in percolation transition district, and it is then less sensitive to volumetric expansion that filler content is higher than the conductive network of matrix material in percolation transition district.Therefore; Be in the matrix material in percolation transition district for filler content, in heat-processed, in the time of near temperature rises to poly fusing point; Its volume sharply expands; So that the conductive network that forms in the matrix material is destroyed, thereby makes the volume specific resistance of matrix material take place sharply to increase, and material becomes state of insulation from conduction state.And be higher than the matrix material in percolation transition district for filler content; In the time of near temperature rises to poly fusing point, its volume is same sharply to expand, but the degree that conductive network wrecks is much lower; Because wherein filler content is high; The conductive network degree of perfection is high, so the increasing degree of matrix material volume resistivity is less, and it is lower to show as PTC intensity.
From the above mentioned, filler content is positioned at the terminal matrix material in percolation transition district and has lower volume specific resistance and high PTC intensity simultaneously concurrently.The inventor thinks; If in having the material of this composition, add fibrous conductive filler material; Particularly, electroconductibility is than the better graphite fibre of carbon black, and the content of bat wool lower (being lower than the percolation threshold of bat wool/Vilaterm binary system) thus avoid in matrix material, forming by its continuous conduction network that constitutes; Just can reduce material local electrical resistance rate, thereby reduce material monolithic resistivity.Because the electroconductibility of graphite fibre is superior to carbon black, and the fiber conduction is unlike carbon black in microcell, and carbon black is to blend contact through exceeding between the particle to realize conduction.Meanwhile, add an amount of fiber, can not influence the destruction of carbon black conductive network in matrix expanded by heating process, thereby keep the existing PTC intensity of matrix material.
Through discovering, in the low-resistivity ptc polymer, carbon black and poly mass ratio 18: 82 to 22: 78, best mass ratio is 20: 80, can satisfy above-mentioned requirements.
Graphite fibre and poly mass ratio are lower than 15: 80, and the quality percentage composition of graphite fibre is 1.9% to 12.2% in the low-resistivity ptc polymer.
Need to prove that the length-to-diameter ratio of bat wool (length and diameter ratio) should be moderate.Length-to-diameter ratio is excessive, and percolation threshold is low, but the processing characteristics of meeting deterioration system; Length-to-diameter ratio is too small, and percolation threshold is high, and the addition that needs is bigger, can cause the deterioration of processing characteristics equally.Preferred length-to-diameter ratio is 15 the graphite fibre that grinds.
Aspect the interpolation order of two kinds of fillers requirement is being arranged also.Bat wool amount ratio carbon black is few, and its dispersing uniformity is determining whether it effectively reduces the system volume specific resistance.Therefore, in the Composite Preparation process, earlier graphite fibre being dispersed in the Vilaterm matrix, and then adding carbon black, is optimal processes.
Prepare according to said ratio, the ptc polymer room temperature resistivity that obtains is low, and PTC intensity is high, can satisfy application need.
Description of drawings
Fig. 1 is the volume specific resistance-content of carbon black figure of PE/CB mixture;
Fig. 2 is the PTC intensity-content of carbon black figure of PE/CB mixture;
Fig. 3 is the graph of a relation between the PTC intensity-volume specific resistance of PE/CB mixture.
Embodiment
By design proportion weighing high density polyethylene(HDPE) (PE) and Shawinigan black (CB), in 160 ℃ of mixing 15 minutes down, rotating speed is 60r/min to the Banbury mixer through the HAAKE torque rheometer with two components.Mixture is molded into the thin plate that thickness is 2mm, and molding temperature is 150 ℃.With dedicated tool from thin plate sampling and testing material volume resistivity.Sample volume resistance is higher than 10
8During Ω, measure, be lower than 10 through megger
8During Ω, test according to four electrode methods through the Keithley multimeter.The material volume resistivity that obtains-content of carbon black relation is as shown in Figure 1.Can find out that the percolation transition zone of matrix material is 10-22wt%, at the interval percolation transition of accomplishing of 18-22wt%.As can beappreciated from fig. 2, the PTC intensity of matrix material reduces with the increase of content of carbon black.When filler content 15wt%, though have high PTC intensity (7 * 10
8), but the room temperature resistivity of matrix material is also higher, is 1.1 * 10
4Ω .cm.When filler content was 35wt%, matrix material had lower volume specific resistance, be 4.56 Ω .cm, but its PTC intensity was also very low, is merely 192.And when filler content was 20wt%, matrix material had high PTC intensity (6 * 10
5) and lower volume specific resistance (46 Ω .cm).If set up the relation between PTC intensity and the matrix material volume resistivity,, can find out then that along with the reduction of matrix material volume resistivity, its PTC intensity is dull to be reduced like Fig. 3.This shows that in the CB/PE system, relying on increases the reduction that content of carbon black reduction volume specific resistance can cause mixture PTC intensity simultaneously.
The technical scheme that proposes according to the present invention, in the matrix material of above-mentioned filler content 20wt%, adding a certain amount of mean diameter and be 10 microns, mean length and be 150 microns, volume specific resistance is 1.4 * 10
-3The graphite fibre of Ω .cm (GF, its content is 15.8wt% when the percolation transition of GF/PE binary system begins).Its technological process is: in temperature is that 160 ℃, rotating speed are under the condition of 60r/min, earlier Vilaterm is added the Banbury mixer fusion, adds load weighted graphite fibre then, mixes 5 minutes, adds carbon black subsequently, continues mixing 15 minutes.Room temperature volume specific resistance and the PTC intensity such as the table 1 of the trielement composite material of preparation.
The room temperature resistivity of table 1 matrix material and PTC intensity
| Numbering | Material is formed and proportioning (mass ratio) | The graphite fibre mass content, % | Room temperature volume specific resistance (Ω .cm) | |
| 0 | PE∶CB∶GF＝80∶20∶0 | 0 | 46 | 6.03×10 5 |
| 1 | PE∶CB∶GF＝80∶20∶1.98 | 1.9 | 44 | 2.73×10 6 |
| 2 | PE∶CB∶GF＝80∶20∶5.94 | 5.6 | 40.5 | 6.09×10 5 |
| 3 | PE∶CB∶GF＝80∶20∶9.90 | 9.0 | 31.2 | 4.03×10 6 |
| 4 | PE∶CB∶GF＝80∶20∶13.86 | 12.2 | 7.4 | 4.22×10 6 |
| 5 | PE∶CB∶GF＝82∶18∶13.6 | 12 | 200 | 3.00×10 6 |
| 6 | PE∶CB∶GF＝78∶22∶13.6 | 12 | 7.39 | 4.21×10 6 |
Can find out from table 1 (numbering 1-4), in the matrix material of content of carbon black 20wt%, keep carbon black and poly constant rate and when increasing the consumption of graphite fibre, the room temperature volume specific resistance of matrix material reduces gradually, and PTC intensity remain unchanged basically.Being numbered in 4 the trielement composite material all, the content of conductive filler materials is 29.7wt%; (the PE/CB binary complex volume specific resistance of CB content 30wt% is 10 Ω .cm to its volume specific resistance, and PTC intensity is 1.46 * 10 a little less than the suitable PE/CB binary complex of filler content
3, see Fig. 1,2), but its PTC intensity is 2900 times of the latter.
Can find out that from table 1 (numbering 5) (room temperature resistivity 310 Ω .cm, PTC intensity is 2.9 * 10 to the CB/PE of content of carbon black 18wt% binary complex
6) in when adding an amount of graphite fibre, can reduce the room temperature resistivity of matrix material equally, and keep PTC intensity constant basically.But because CB/PE binary complex self room temperature resistivity of content of carbon black 18wt% is higher, the room temperature resistivity of matrix material is also higher behind the adding graphite fibre, is higher than the material of numbering 4.It can also be seen that from table 1 (numbering 6) (room temperature resistivity 45 Ω .cm, PTC intensity is 4 * 10 to the CB/PE of content of carbon black 22wt% binary complex
6) in when adding an amount of graphite fibre, also can reduce the room temperature resistivity of matrix material, keep PTC intensity constant basically simultaneously.But need this moment to add more carbon black, this can make the processing characteristics of matrix material degenerate, and its room temperature resistivity has remarkable reduction unlike the material that is numbered 4.This shows that carbon black and poly best proportioning are 20: 80.
Above data show; PTC matrix material according to technical scheme preparation of the present invention has lower room temperature resistivity and high PTC intensity really; Its room temperature resistivity can be lower than the CB/PE binary complex of identical filler content, but PTC intensity can be higher than the CB/PE binary complex of identical filler content far away.Thereby show that technical scheme proposed by the invention is effective for the polymer PTC matrix material of preparation low-resistivity, high PTC intensity.
Claims (4)
1. a low-resistivity ptc polymer comprises Vilaterm, carbon black, it is characterized in that: in described material, also include graphite fibre;
Described carbon black and poly mass ratio 18:82 to 22:78;
Described graphite fibre and poly mass ratio are lower than 15:80, and the quality percentage composition of graphite fibre is 1.9% to 12.2% in the low-resistivity ptc polymer;
Described low-resistivity ptc polymer is under the condition of 160 ℃ of temperature, rotating speed 60r/min, in Banbury mixer, earlier with the Vilaterm fusion, adds graphite fibre again, mixes after 5 minutes, add carbon black again, mixes to make in 15 minutes.
2. low-resistivity ptc polymer according to claim 1 is characterized in that: described carbon black and poly mass ratio are 20:80.
3. low-resistivity ptc polymer according to claim 1 is characterized in that: described graphite fibre length and diameter ratio are 15.
4. the preparation method of the said low-resistivity ptc polymer of the arbitrary claim of claim 1 to 3 is characterized in that comprising the steps:
Under the condition of 160 ℃ of temperature, rotating speed 60r/min, in Banbury mixer,, add graphite fibre more earlier with the Vilaterm fusion, mix after 5 minutes, add carbon black again, mixed 15 minutes, promptly make described low-resistivity ptc polymer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110021957 CN102167859B (en) | 2011-01-20 | 2011-01-20 | Low-resistivity polymer positive temperature coefficient material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110021957 CN102167859B (en) | 2011-01-20 | 2011-01-20 | Low-resistivity polymer positive temperature coefficient material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102167859A CN102167859A (en) | 2011-08-31 |
| CN102167859B true CN102167859B (en) | 2012-12-12 |
Family
ID=44489191
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201110021957 Expired - Fee Related CN102167859B (en) | 2011-01-20 | 2011-01-20 | Low-resistivity polymer positive temperature coefficient material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102167859B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1970612A (en) * | 2006-10-25 | 2007-05-30 | 东华大学 | Preparation method of electrically conductive composite material with positive temperature coefficient effect |
| CN101597396A (en) * | 2009-07-02 | 2009-12-09 | 浙江华源电热有限公司 | Polymer-based positive temperature coefficient thermistor material |
-
2011
- 2011-01-20 CN CN 201110021957 patent/CN102167859B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1970612A (en) * | 2006-10-25 | 2007-05-30 | 东华大学 | Preparation method of electrically conductive composite material with positive temperature coefficient effect |
| CN101597396A (en) * | 2009-07-02 | 2009-12-09 | 浙江华源电热有限公司 | Polymer-based positive temperature coefficient thermistor material |
Non-Patent Citations (3)
| Title |
|---|
| 张晓玲."石墨（碳）纤维/碳黑/聚合物PTC导电复合材料的研究".《中国优秀硕士学位论文全文数据库 工程科技I辑》.2010,(第09期),27-36. |
| 张晓玲."石墨(碳)纤维/碳黑/聚合物PTC导电复合材料的研究".《中国优秀硕士学位论文全文数据库 工程科技I辑》.2010,(第09期),27-36. * |
| 沈烈等.聚乙烯/炭黑/碳纤维复合材料阻温特性.《复合材料学报》.2001,(第03期), * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102167859A (en) | 2011-08-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Xi et al. | Positive temperature coefficient effect of LMWPE–UHMWPE blends filled with short carbon fibers | |
| Yang et al. | Electrical properties and morphology of carbon black‐filled HDPE/EVA composites | |
| US5106540A (en) | Conductive polymer composition | |
| US5106538A (en) | Conductive polymer composition | |
| CN106317544B (en) | Conductive polymer compositions, conducting polymer sheet material, electric device and their preparation method | |
| Mironi‐Harpaz et al. | Electrical behavior and structure of polypropylene/ultrahigh molecular weight polyethylene/carbon black immiscible blends | |
| EP3021331A1 (en) | Positive temperature coefficient composition | |
| CN105295190A (en) | Functionalized high polymer composite material with carbon black and graphene as conductive mediums | |
| Liang et al. | Effects of carbon black content and size on conductive properties of filled high‐density polyethylene composites | |
| Feller | Conductive polymer composites: Influence of extrusion conditions on positive temperature coefficient effect of poly (butylene terephthalate)/poly (olefin)–carbon black blends | |
| CN101556849A (en) | Macromolecular positive temperature coefficient thermosensitive resistor and manufacturing method thereof | |
| CN105837950B (en) | A kind of polyolefin-based conductive and dielectric composite material and preparation method thereof | |
| JP3813611B2 (en) | Conductive polymer having PTC characteristics, method for controlling PTC characteristics of the polymer, and electronic device using the polymer | |
| Das et al. | Effect of filler treatment and crosslinking on mechanical and dynamic mechanical properties and electrical conductivity of carbon black‐filled ethylene–vinyl acetate copolymer composites | |
| US9773589B1 (en) | PTC circuit protection device | |
| CN1803905A (en) | Electric conductive polymer and overcurrent protection element | |
| EP0371059A1 (en) | Conductive polymer composition | |
| GB2569532A (en) | Improved positive temperature coefficient ink composition without negative temperature coefficient effect | |
| CN102167859B (en) | Low-resistivity polymer positive temperature coefficient material and preparation method thereof | |
| CN100372029C (en) | PTC thermosensitive resistor parts and PTC thermosensitive resistor and producing method thereof | |
| CN105037871B (en) | A kind of PPTC chips and its preparation method | |
| JP2000331804A (en) | Ptc composition | |
| CN107230511A (en) | Conductive polymer compositions, electric device and preparation method thereof | |
| CN101819837B (en) | Over-current and over-temperature protection element with positive temperature coefficient and preparation method thereof | |
| CN113826174A (en) | PPTC compositions and devices with low thermal deration and low process jump |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121212 Termination date: 20220120 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |