GB1600256A - Process for the manufacture of electrical devices comprising conductive polymer compositions - Google Patents
Process for the manufacture of electrical devices comprising conductive polymer compositions Download PDFInfo
- Publication number
- GB1600256A GB1600256A GB50916/77A GB5091677A GB1600256A GB 1600256 A GB1600256 A GB 1600256A GB 50916/77 A GB50916/77 A GB 50916/77A GB 5091677 A GB5091677 A GB 5091677A GB 1600256 A GB1600256 A GB 1600256A
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- Prior art keywords
- process according
- conductive polymer
- polymer composition
- composition
- electrode
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- Expired
Links
- 239000000203 mixture Substances 0.000 title claims description 81
- 229920001940 conductive polymer Polymers 0.000 title claims description 36
- 238000000034 method Methods 0.000 title claims description 35
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 239000006229 carbon black Substances 0.000 claims description 14
- 229920000642 polymer Polymers 0.000 claims description 13
- 238000002844 melting Methods 0.000 claims description 11
- 230000008018 melting Effects 0.000 claims description 11
- 238000004132 cross linking Methods 0.000 claims description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 5
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052709 silver Inorganic materials 0.000 claims description 3
- 239000004332 silver Substances 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229920001169 thermoplastic Polymers 0.000 claims description 2
- 239000004416 thermosoftening plastic Substances 0.000 claims description 2
- 235000019241 carbon black Nutrition 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 5
- 229920001971 elastomer Polymers 0.000 description 5
- 239000005060 rubber Substances 0.000 description 5
- 238000011282 treatment Methods 0.000 description 4
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000011231 conductive filler Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- 102100027207 CD27 antigen Human genes 0.000 description 1
- 239000004709 Chlorinated polyethylene Substances 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 101000914511 Homo sapiens CD27 antigen Proteins 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010382 chemical cross-linking Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229920001179 medium density polyethylene Polymers 0.000 description 1
- 239000004701 medium-density polyethylene Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005382 thermal cycling Methods 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
- H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
- H05B3/146—Conductive polymers, e.g. polyethylene, thermoplastics
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
- H01C7/027—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Ceramic Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Dispersion Chemistry (AREA)
- Resistance Heating (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Conductive Materials (AREA)
- Thermistors And Varistors (AREA)
- Control Of Resistance Heating (AREA)
- Apparatuses And Processes For Manufacturing Resistors (AREA)
Description
(54) A PROCESS FOR THE MANUFACTURE OF ELECTRICAL DEVICES
COMPRISING CONDUCTIVE POLYMER COMPOSITIONS
(71) We, RAYCHEM CORPORATION, A Corporation organized according to the laws of the State of California, United States of America, of 300 Constitution Drive, Menlo
Park, California 94025, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
This invention relates to a process for the manufacture of an electrical device in which an electrode is in contact with a conductive polymer composition.
Conductive polymer compositions are well known. They comprise organic polymers having dispersed therein a finely divided conductive filler, for example carbon black or a particulate metal. Some such compositions exhibit so-called PTC (Positive Temperature
Coefficient) behaviour. The terminology which has been used in the past to describe PTC behaviour is variable and often imprecise.In this specification, the terms "composition exhibiting PTC behaviour" and "PTC composition" are used to denote a composition having at least one temperature range (hereinafter called a "critical range") which is within the limits of - 10()0C and about 250"C; at the beginning of which the composition has a resistivity below about 105 ohm. cm.; and in which the composition has an R14 value of at least 2.5 or an R1()() value of at least 10 (and preferably both), and preferably has an R3() value of at least 6. where R14 is the ratio of the resisitivities at the end and the beginning of a 14"C range, R1() is the ratio of the resisitivities at the end and the beginning of a 1DO"C range, and R(, is the ratio of the resistivities at the end and the beginning of a 30 C range.
The term "PTC element" is used herein to denote an element composed of a PTC composition as defined above. A plot of the log of the resistance of a PTC element, measured between two electrodes in contact with the element, against temperature, will often, though by no means invariably. show a sharp change in slope over a part of the critical temperature range, and in such cases, the term "switching temperature" (usually abbreviated to Ts) is used herein to denote the temperature at the intersection point of extensions of the substantially straight portions of such a plot which lie each side of the portion showing the sharp change in slope. The PTC composition in such a PTC element is described herein as having "a useful Ts". The Ts is preferably between 0 C and 175"C., e.g.
50"C to 1200C.
Conductive polymer compositions, especially PTC compositions, are useful in electrical devices in which the composition is in contact with an electrode, usually of metal. Devices of this kind are usually manufactured by methods comprising extruding or moulding the molten polymer composition around or against the electrode or electrodes.In the known methods, the electrode is not heated prior to contact with the polymer composition or is heated only to a limited extent, for example to a temperature well below the melting point of the composition, for example not more than 65"C as in conventional wire-coating techniques. (Temperatures are in "C throughout this specification.) Well known examples of such devices are flexible strip heaters which comprise a generally ribbon-shaped core of the conductive polymer composition, a pair of longitudinally extending electrodes, generally of stranded wire, embedded in the core near the edges thereof, and an outer layer of a protective and insulating composition. Particularly useful heaters are those in which the composition exhibits PTC behaviour, and which are therefore self-regulating.In the preparation of such heaters in which the composition contains less than 15% of carbon black, the prior art has taught that it is necessary, in order to obtain a sufficiently low resistivity, to anneal the heater for an extended period such that
2L + 5 log,o RS 45 where L is the percent by weight of carbon and R is the resistivity in ohm.cm. at room temperature.
A disadvantage which arises with devices comprising an electrode and a conductive polymer composition in contact with the electrode, and in particular with strip heaters, is that the longer they are in service the higher is their resistance and the lower is their power output, particularly when they are subject to thermal cycling.
It is known that variation, from device to device, of the contact resistance between electrodes and carbon-black-filled rubbers is an obstacle to comparison of the electrical characterisitics of such devices and to the accurate measurement of the resistivity of such rubbers, particularly at high resistivities and low voltages; and it has been suggested that the same is true of other conductive polymer compositions. Various methods have been suggested for reducing the contact resistance between carbon-black-filled rubbers and test electrodes placed in contact therewith. The preferred method is to vulcanise the rubber while it is in contact with a brass electrode. Other methods include copper-plating, vacuum-coating with gold, and the use of colloidal solutions of graphite between the electrode and the test piece.For details, reference should be made to Chapter 2 of "Conductive Rubbers and Plastics" by R.H. Norman, published by Applied Science
Publishers (1970), from which it will be clear that the factors which govern the size of such contact resistance are not well understood.
We have now discovered that the less is the initial contact resistance between an electrode and a conductive polymer composition, the smaller is the increase in total resistance with time. We have also discovered that by placing or maintaining an electrode and a polymer composition in contact with each other while both are at a temperature above the melting point of the composition, the contact resistance between them is reduced. The term "melting point of the composition" is used herein to denote the temperature at which the composition begins to melt. The time for which the electrode and the composition need be in contact with each other, while each is at a temperature above the melting point of the composition, in order to achieve the desired result, is quite short.
Times in excess of five minutes do not result in any substantial further reduction of contact resistance, and often times less than 1 minute are quite adequate and are therefore preferred. Thus the treatment time is of a quite different order from that required by the known annealing treatments to decrease the resistivity of the composition, as described for example in U.S. Patents Nos. 3,823,217 and 3,914,363.
The present invention provides a process for the manufacture of a device comprising an electrode and a conductive polymer composition in contact therewith, which process comprises
(1) heating a conductive polymer composition to a temperature (Tp) above its melting
point (Tm);
(2) heating an electrode, out of contact with the conductive polymer composition, to a
temperature (Te) above the melting point of the conductive polymer composition;
(3) contacting the electrode, while it is at a temperature above Tm, with the molten
polymer composition; and
(4) cooling the electrode and conductive polymer composition in contact therewith.
Preferably both Tp and Te are at least 20 C, especially at least 550C, above Tm. It is often preferably that both Tp and Te should be above the Ring-and-Ball softening temperature of the polymer composition.
Preferably the conductive polymer composition is subjected to pressure to assist in bringing it into close conformity with the electode. The pressure is generally at least 14 kg/cm;, preferably at least 21 kg/cm2, for example 21 to 200 kg/cm2, especially at least 35 kg/cm-, e.g. 35-70 kg/cm2.
We have also found that for strip heaters, currently the most widely used devices in which current is passed through conductive polymer compositions, the contact resistance can be correlated with the linearity ratio, a quantity which can readily be measured as described below. Accordingly, in Application No. 26479/80 (Serial No. 1600257), filed 14th August 1980 and divided from this Application, there is claimed a strip heater comprising:
(1) an elongate core of a conductive polymer composition which exhibits PTC behavior, which comprises carbon black, and in which, if the content (L) of carbon black in percent by weight is less than 15, L and the resistivity R of the composition in ohm. cm at room temperature are such that
2L + 5 loglO R > 45;
(2) at least two longitudinally extending electrodes embedded in said composition parallel to each other; and
(3) an outer layer of a protective and insulating composition; the average linearity ratio (and preferably the linearity ratio at all points) between any pair of electrodes being at most 1.2, preferably at most 1.15, especially at most 1.10. The linearity ratio of a strip heater is defined as
Resistance at 30 MV.
Resistance at 100 V.
the resistances being measured at 21"C between two electrodes which are contacted by probes pushed through the outer jacket and the conductive polymeric core of the strip heater. The contact resistance is negligible at 100 V., so that the closer the linearity ratio is to 1, the lower the contact resistance.
The present invention is useful with any type of electode, for example metal plate, strips or wires, but particularly so with electrodes having an irregular surface, e.g. stranded wire electrodes as conventionally used in strip heaters, braided wire electrodes (for example as described in German Offenlegungschrift No. 2,635,000.5) and expansible electrodes as described in German Offenlegungschrift No. 2,655,543.1. Preferred stranded wires are silver-coated and nickel-coated copper wires, which are ]ess susceptible to difficulties, such as melting or oxidation, than tin-coated or uncoated copper wires, though the latter can be used without difficulty providing the temperatures employed are not too high.
The conductive polymer compositions used in this invention generally contain carbon black as the conductive filler, e.g. in amount greater or less than 15% by weight, for example greater than 17% or 20% by weight. In many cases, it is preferred that the compositions should exhibit PTC behavior. The resistivity of the composition is generally less than 50,000 ohm.cm at 21"C, for example 100 to 50,000 ohm.cm. For strip heaters designed to be powered by A.C. of 115 volts or more, the composition generally has a resistivity of 2,000 to 50,000 ohm.cm, e.g. 2,000 to 40,000 ohm.cm. The composition is preferably thermoplastic when applied to the electrode. However, it may be lightly cross-linked, or be in the process of being cross-linked, provided that it is sufficiently fluid under the contacting conditions to conform closely to the electrode surface.The polymer is preferably a crystalline polymer.
Strip heaters manufactured by the process of the present invention generally have two electrodes separated by a distance of 0.15 to 1 cm, but greater separations, e.g. up to 2.5 cm. or even more, can be used. The core of conductive polymer can be of conventional shape. but preferably its major transverse dimension is not more than 3 times, especially not more than 1.5 times, e.g. not more than 1.1 times, its smallest dimension. A core of round cross-section is especially preferred.
As indicated above. the electrode and the polymer composition are heated separately before being contacted. It is preferred that the composition be melt-extruded over the electrode, e.g. by extrusion around a pair of spaced-apart wire electrodes using a cross-head die. The electrode is pre-heated to a temperature (Te) which may be greater or less than the temperature of the molten polymer composition (Tp) but is generally more than (Tp55)0C and preferably more than (Tp30) C. T will normally be substantially above the melting point of the composition, for example 36 to 80"C above. Of course, neither the electrode
nor the composition should be heated to a temperature at which it undergoes substantial oxidation or other degradation.
Particularly when the conductive polymer composition exhibits PTC behavior, it is often desirable that in the final product the composition should be cross-linked. Cross-linking can
be carried out as a separate step after the treatment to reduce contact resistance; in this case, cross-linking with aid of radiation is preferred. Alternatively cross-linking can be carried out simultaneously with the said treatment, in which case chemical cross-linking with the aid of cross-linking initiators such as peroxides is preferred.
The invention is illustrated by the following Examples, some of which are comparative
Examples.
In each of the Examples a strip heater was prepared as described below. The conductive
polymer composition was obtained by blending a medium density polyethylene containing
an antioxidant with a carbon black master batch comprising an ethylene/ethyl acrylate copolymer to give a composition containing the indicated percent by weight of carbon black. The melting point of the composition was about 115"C. The composition was melt-extruded at a melt temperature of about 1800C through a cross-head die having a circular orifice 0.36 cm in diameter over a pair of stranded silver-coated copper wires, each wire having a diameter of 0.08 cm and comprising 19 strands, and the axes of the wires being on a diameter of the orifice and 0.2 cm apart.Before reaching the cross-head die, the wires were pre-heated by passing them through an oven 60 cm long at 800"C. The temperature of the wires entering the die was 82 C in the comparative Examples 1,4 and 6, in which the speed of the wires through the oven and the die was 21m/min, 165"C in
Examples 2 and 7 and 193"C in Examples 3 and 5.
The extrudate was then given an insulating jacket by melt-extruding around it a layer 0.051 cm thjck of chlorinated polyethylene or an ethylene/tetrafluoroethylene copolymer.
The coated extudate was then irradiated in order to cross-link the conductive polymer composition.
Examples 1-3
These Examples, in which Example 1 is a comparative Example, demonstrate the influence of Linearity Ratio (LR) on Power Output when the heater is subjected to temperature changes. In each Example, the Linearity Ratio of the heater was measured and the heater was then connected to a 120 volt AC supply and the ambient temperature was changed continuously over a 3 minute cycle, being raised from -37 C to 650C over a period of 90 seconds and then reduced to -370C again over the next 90 seconds.
The peak power output of the heater during each cycle was measured initially and at intervals and expressed as a proportion (PN) of the initial peak power output.
The polymer composition used in Example 1 contained about 26% carbon black. The polymer composition used in Examples 2 and 3 contained about 22% carbon black.
The results obtained are shown in Table 1 below.
TABLE 1
No. of Cycles Example 1 Example 2 Example 3
PN LR PN LR PN LR
None 1 1.3 1 1.1 1 1
500 0.5 1.6 1.3 - 1 1
1100 0.3 2.1 1.2 - 1 1
1700 - - 1.1 1.1 1 1
*Comparative Example
Examples 4-7
These Examples. which are summarised in Table 2 below, demonstrate the effect of
pre-heating the electrodes on the Linearity Ratio of the product.
TABLE 2
Example No. % Carbon Black Linearity Ratio 4 22 1.6
5 22 1.0 6 23 1.35
7 23 1.1 Comparative Example
Claims (20)
1. A process for the manufacture of a device comprising an electrode and a conductive polymer composition in contact therewith, which process comprises
(1) heating a conductive polymer composition to a temperature (Tp) above its melting
point (Tm);
(2) heating an electrode, out of contact with the conductive polymer composition, to a
temperature (Te) above the melting point of the conductive polymer composition;
(3) contacting the electrode, while it is at a temperature above Tm, with the molten
polymer composition; and
(4) cooling the electrode and conductive polymer composition in contact therewith.
2. A process according to claim 1, wherein the conductive polymer composition exhibits
PTC behavior (as hereinbefore defined).
3. A process according to claim 1 or 2, wherein the polymeric composition is thermoplastic.
4. A process according to any one of the preceding claims, wherein Te is at least (T -55)0C.
A A A process according to any one of the preceding claims, wherein both Tp and Te are at least 20"C above Tm.
6. A process according to claim 5, wherein both Tp and Te are at least 55"C above Tm.
7. A process according to any one of the preceding claims, wherein both T and Te are above the Ring-and-Ball softening point of the conductive polymer composition.
8. A process according to any one of the preceding claims, wherein the conductive polymer composition is melt-extruded over at least two spaced-apart electrodes.
9. A process according to claim 8, wherein the conductive polymer composition is extruded over a pair of stranded wire electrodes.
10. A process according to claim 9, wherein the electrodes are separated by a distance of 0.15 to 1 cm.
11. A process according to any one of claims 8 to 10, wherein the electrodes are silver-coated copper wires or nickel-coated copper wires.
12. A process according to any one of claims 8 to 11, wherein the conductive polymer composition is extruded as an extrudate having a cross-section in which the largest dimension is not more than 3 times the smallest dimension.
13. A process according to any one of the preceding claims, wherein the conductive polymer composition exhibits PTC behavior and has a resistivity at 21"C of 100 to 50,000 ohm.cm.
14. A process according to any one of the preceding claims, wherein the conductive polymer composition contains at least 15% by weight of carbon black.
15. A process according to any one of the preceding claims, wherein the conductive polymer composition contains carbon black dispersed in a crystalline polymer and exhibits
PTC behavior.
16. A process according to claim 1 substantially as hereinbefore described.
17. A process according to claim 1 substantially as described in any one of Examples 2, 3, 5 and 7.
18. A process according to any one of the preceding claims which also comprises the further step of cross-linking the conductive composition.
19. A process according to claim 18, wherein the cross-linking is effected by irradiation.
20. A device comprising an electrode and a conductive polymer composition which has been prepared by a process as claimed in any one of the preceding claims.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US75014976A | 1976-12-13 | 1976-12-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1600256A true GB1600256A (en) | 1981-10-14 |
Family
ID=25016715
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB50916/77A Expired GB1600256A (en) | 1976-12-13 | 1977-12-07 | Process for the manufacture of electrical devices comprising conductive polymer compositions |
| GB26479/80A Expired GB1600257A (en) | 1976-12-13 | 1977-12-07 | Strip heaters comprising conductive polymer compositions |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB26479/80A Expired GB1600257A (en) | 1976-12-13 | 1977-12-07 | Strip heaters comprising conductive polymer compositions |
Country Status (10)
| Country | Link |
|---|---|
| JP (4) | JPS6057192B2 (en) |
| AU (1) | AU515034B2 (en) |
| BE (1) | BE861776A (en) |
| CA (2) | CA1106890A (en) |
| DE (1) | DE2755077A1 (en) |
| FR (1) | FR2392572A1 (en) |
| GB (2) | GB1600256A (en) |
| NL (1) | NL185545C (en) |
| NO (1) | NO147735C (en) |
| SE (3) | SE434587B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113635534A (en) * | 2021-08-10 | 2021-11-12 | 芜湖佳宏新材料股份有限公司 | Process method for reducing contact resistance of conductive polymer and metal conductor |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4238812A (en) * | 1978-12-01 | 1980-12-09 | Raychem Corporation | Circuit protection devices comprising PTC elements |
| GB2052228B (en) * | 1979-05-10 | 1983-04-07 | Sunbeam Corp | Flexible heating elements and dies and processes for the production thereof |
| CA1156300A (en) * | 1980-04-01 | 1983-11-01 | Gordon S. Carlson | Electric blanket safety circuit |
| US4591700A (en) * | 1980-05-19 | 1986-05-27 | Raychem Corporation | PTC compositions |
| CA1168433A (en) * | 1980-05-19 | 1984-06-05 | Umesh K. Sopory | Ptc conductive polymers and devices comprising them |
| US4309596A (en) * | 1980-06-24 | 1982-01-05 | Sunbeam Corporation | Flexible self-limiting heating cable |
| ATE77155T1 (en) | 1983-06-30 | 1992-06-15 | Raychem Corp | METHOD OF DETECTING AND OBTAINING INFORMATION ABOUT THE CHANGES OF VARIABLES. |
| GB8623082D0 (en) * | 1986-09-25 | 1986-10-29 | Raychem Gmbh | Heated conduit |
| DE4024268A1 (en) * | 1990-07-31 | 1992-02-06 | Lehmann & Voss & Co | Electroconductive plastics element for heater or electronic device - contains synergistic mixt. of carbon or graphite powder and fibres and opt. metal fibres |
| DE4307371A1 (en) * | 1993-03-09 | 1994-09-15 | Hit Hillesheim Innovations Und | Heatable line for a flow medium |
| DE4426188A1 (en) * | 1994-07-23 | 1996-01-25 | Mekra Rangau Plastics | Outside mirrors for motor vehicles |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB828334A (en) * | 1956-10-30 | 1960-02-17 | British Insulated Callenders | Improvements in or relating to electrically conductive non-metallic materials |
| US3861029A (en) * | 1972-09-08 | 1975-01-21 | Raychem Corp | Method of making heater cable |
| US3858144A (en) | 1972-12-29 | 1974-12-31 | Raychem Corp | Voltage stress-resistant conductive articles |
| JPS5432173B2 (en) * | 1974-03-29 | 1979-10-12 | ||
| JPS5530669B2 (en) * | 1974-03-29 | 1980-08-12 | ||
| US4177376A (en) * | 1974-09-27 | 1979-12-04 | Raychem Corporation | Layered self-regulating heating article |
| ES454025A1 (en) * | 1975-12-08 | 1977-11-16 | Raychem Corp | Expansible heater |
-
1977
- 1977-12-07 GB GB50916/77A patent/GB1600256A/en not_active Expired
- 1977-12-07 GB GB26479/80A patent/GB1600257A/en not_active Expired
- 1977-12-09 FR FR7737164A patent/FR2392572A1/en active Granted
- 1977-12-09 AU AU31394/77A patent/AU515034B2/en not_active Expired
- 1977-12-10 DE DE19772755077 patent/DE2755077A1/en active Granted
- 1977-12-12 NO NO774258A patent/NO147735C/en unknown
- 1977-12-12 CA CA292,832A patent/CA1106890A/en not_active Expired
- 1977-12-12 BE BE183389A patent/BE861776A/en not_active IP Right Cessation
- 1977-12-13 JP JP52149792A patent/JPS6057192B2/en not_active Expired
- 1977-12-13 SE SE7714126A patent/SE434587B/en not_active IP Right Cessation
- 1977-12-13 NL NL7713800A patent/NL185545C/en not_active IP Right Cessation
-
1983
- 1983-07-19 SE SE8304042A patent/SE447781B/en not_active IP Right Cessation
-
1985
- 1985-08-09 CA CA000488467A patent/CA1206507B/en not_active Expired
- 1985-10-28 SE SE8505088A patent/SE8505088D0/en not_active Application Discontinuation
-
1989
- 1989-05-22 JP JP1128617A patent/JPH0256887A/en active Granted
- 1989-05-22 JP JP1128616A patent/JPH0256886A/en active Granted
-
1990
- 1990-10-23 JP JP2286933A patent/JPH03257783A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113635534A (en) * | 2021-08-10 | 2021-11-12 | 芜湖佳宏新材料股份有限公司 | Process method for reducing contact resistance of conductive polymer and metal conductor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0562439B2 (en) | 1993-09-08 |
| DE2755077C2 (en) | 1987-06-11 |
| JPS6057192B2 (en) | 1985-12-13 |
| JPH0559557B2 (en) | 1993-08-31 |
| DE2755077A1 (en) | 1978-06-29 |
| NL185545B (en) | 1989-12-01 |
| FR2392572A1 (en) | 1978-12-22 |
| CA1106890A (en) | 1981-08-11 |
| NO774258L (en) | 1978-06-14 |
| SE8505088L (en) | 1985-10-28 |
| SE447781B (en) | 1986-12-08 |
| NL7713800A (en) | 1978-06-15 |
| JPH053120B2 (en) | 1993-01-14 |
| BE861776A (en) | 1978-06-12 |
| CA1206507B (en) | 1986-06-24 |
| SE8304042L (en) | 1983-07-19 |
| GB1600257A (en) | 1981-10-14 |
| AU515034B2 (en) | 1981-03-12 |
| JPH0256886A (en) | 1990-02-26 |
| SE434587B (en) | 1984-07-30 |
| SE7714126L (en) | 1978-06-14 |
| JPH03257783A (en) | 1991-11-18 |
| SE8304042D0 (en) | 1983-07-19 |
| JPS5395298A (en) | 1978-08-21 |
| NO147735B (en) | 1983-02-21 |
| NO147735C (en) | 1983-06-01 |
| AU3139477A (en) | 1979-06-14 |
| SE8505088D0 (en) | 1985-10-28 |
| JPH0256887A (en) | 1990-02-26 |
| NL185545C (en) | 1995-01-16 |
| FR2392572B1 (en) | 1984-03-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| 429A | Application made for amendment of specification (sect. 29/1949) | ||
| 727A | Application for amendment of specification now open to opposition (sect. 27/1977) | ||
| 429A | Application made for amendment of specification (sect. 29/1949) | ||
| SP | Amendment (slips) printed | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19961207 |