Process for Producing PTC Device

• US 20090223035A1
• Filed: 12/07/2006
• Published: 09/10/2009
• Est. Priority Date: 12/09/2005
• Status: Active Grant

• Current Assignee: Littelfuse Japan G.K. (Littelfuse Incorporated)
• Original Assignee: Tyco Electronics Raychem KK (TE Connectivity Ltd. (United Kingdom))
• Inventors: Suzuki, Katsuaki, Tanaka, Arata
• Granted Patent: US 8,590,142 B2
• Time in Patent Office: Days
• US Class Current: 29/612
• CPC Class Codes: H01C 1/1406 Terminals or electrodes formed on resistive elements having positive temperature coefficient
• CPC Class Codes: H01C 17/281 by thick film techniques
• CPC Class Codes: H01C 7/027 consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
• CPC Class Codes: Y10T 29/49085 Thermally variable
• CPC Class Codes: Y10T 29/49107 Fuse making
• CPC Class Codes: Y10T 29/49179 by metal fusion bonding

Abstract

There is provided a polymer PTC device including a polymer PTC element having a lower resistance. The production process of a PTC device which includes a PTC element (102) having a polymer PTC component (110) and metal electrodes (104) placed on both sides thereto; and a lead (106) connected electrically to at least one of the metal electrodes, is characterized in that the polymer PTC component is formed of an electrically conductive polymer composition which comprises a polymer material and conductive fillers dispersed therein, and the connection of the lead to the metal electrode is performed at a temperature which is lower than the melting point of the polymer material.

Claims

1. A process of producing a PTC device which comprises

providing a PTC element having a polymer PTC component and metal electrodes placed on both sides thereto, the PTC component being formed of an electrically conductive polymer composition comprising a polymer material having a melting point and a conductive filler dispersed therein;

and

electrically connecting a lead to at least one of the metal electrodes at a temperature which is lower than the melting point of the polymer material.

2. The process according to claim 1, wherein the connection of the lead to the metal electrode is performed by an electrically conductive adhesive placed between the lead and the metal electrode.

3. The process according to claim 2, wherein the electrically conductive adhesive comprises a UV-curable resin and the lead is connected to the metal electrode by UV irradiation of the electrically conductive adhesive placed between the lead and the metal electrode so as to cure the UV-curable resin.

4. The process according to claim 2, wherein the electrically conductive adhesive comprises a moisture-curable resin and the lead is connected to the metal electrode by curing the moisture-curable resin by means of moisture around the electrically conductive adhesive placed between the lead and the metal electrode.

5. The process according to claim 2, wherein the electrically conductive adhesive comprises a thermosetting resin having a curing temperature lower than the melting point of the polymer material, and the lead is connected to the metal electrode by heating the conductive adhesive placed between the lead and the metal electrode so as to cure the thermosetting resin.

6. The process according to claim 5, wherein the curing temperature of the thermosetting resin is at least 20°

C. lower than the melting point of the polymer material.

7. The process according to claim 5, wherein the curing temperature of the thermosetting resin is at least 30°

C. lower than the melting point of the polymer material.

8. The process according to claim 5, wherein the polymer material is a high density polyethylene, and the electrically conductive adhesive comprises an epoxy resin.

9. The process according to claim 5, wherein the polymer material is a polyvinylidene fluoride, and the electrically conductive adhesive comprises an epoxy resin.

10. The process according to claim 1, wherein the connection of the lead to the metal electrode is performed by heating a solder material placed between the lead and the metal electrode so as to melt the solder material, said solder material having a melting point lower than that of the polymer material.

11. The process according to claim 1, wherein the PTC device is obtained as a product by completing the connection of the lead to the metal electrode.

12. A polymer PTC device produced by the process comprising

providing a PTC element having a polymer PTC component and metal electrodes placed on both sides thereto, the PTC component being formed of an electrically conductive polymer composition comprising a polymer material having a melting point and a conductive filler dispersed therein;

and

electrically connecting a lead to at least one of the metal electrodes at a temperature which is lower than the melting point of the polymer material.

13. The polymer PTC device according to claim 12 wherein the lead is connected by an electrically conductive adhesive.

14. The polymer PTC device according to claim 13 wherein the electrical conductive adhesive comprises a UV curable resin.

15. The polymer PTC device according to claim 13 wherein the electrically conductive adhesive comprises a moisture-curable resin.

16. The polymer PTC device according to claim 13 wherein the electrically conductive adhesive comprises a thermosetting resin.

17. The polymer PTC device according to claim 13 wherein the polymer material is a high density polyethylene, and the electrically conductive adhesive comprises an epoxy resin.

18. The polymer PTC device according to claim 13 wherein the polymer material is a polyvinylidene fluoride, and the electrically conductive adhesive comprises an epoxy resin.

19. The polymer PTC device according to claim 12 wherein the connection of the lead to the metal electrode is performed by heating a solder material placed between the lead and the metal electrode so as to melt the solder material, said solder material having a melting point lower than that of the polymer material.