Process for manufacturing a composite polymeric circuit protection device
View Patent ↗A process for manufacturing a composite polymeric circuit protection device in which a polymeric assembly is provided and is then subdivided into individual devices. The assembly is made by providing first and second laminates, each of which includes a laminar polymer element having at least one conductive surface, providing a pattern on at least one of the conductive surfaces on one laminate, securing the laminates in a stack in a desired configuration, at least one conductive surface of at least one of the laminates forming an external conductive surface of the stack, and making a plurality of electrical connections between a conductive surface of the first laminate and a conductive surface of the second laminate. The laminar polymer elements may be PTC conductive polymer compositions, so that the individual devices made by the process exhibit PTC behavior.
1. A process for manufacturing a composite polymeric circuit protection device, said process comprising
(1) providing a polymeric assembly comprising
(a) providing first and second laminates, each of which comprises a laminar polymer element having two conductive surfaces,
(b) providing a pattern of conductive material on at least one of the conductive surfaces on one laminate;
(c) securing the laminates in a stack in a desired configuration by means of an adhesive, one conductive surface of each of the first and second laminates comprising an external conductive surface of the stack, and
(d) making a plurality of electrical connections between a conductive surface of the first laminate and a conductive surface of the second laminate; and
(2) subdividing the assembly into individual devices each of which comprises at least one electrical connection.
2. The process according to claim 1 , wherein the pattern in step (b) is formed by selectively removing a portion of conductive material from at least one of the conductive surfaces on one laminate.
3. The process according to claim 2 , wherein the selective removal of conductive material is accomplished by etching, milling, or stamping.
4. The process according to claim 1 , which further comprises providing a pattern of conductive material on at least one of the external conductive surfaces.
5. The process according to claim 4 , wherein the pattern on the external conductive surface is formed by selectively removing a portion of conductive material from the external conductive surface.
6. The process according to claim 4 , wherein at least one of the patterned external conductive surfaces is at least partially covered with an insulating layer.
7. The process according to claim 4 , wherein the patterns on the internal and external conductive surfaces are different.
8. The process according to claim 1 , wherein an additional conductive layer is added to at least part of at least one of the external conductive surfaces.
9. The process according to claim 1 , wherein at least one laminate is marked to provide a unique identification of orientation.
10. The process according to claim 9 , wherein the laminate markings which provide a unique identification of orientation also provide delineation for subdividing into individual devices.
11. The process according to claim 1 , wherein the assembly comprises a third laminate.
12. The process according to claim 11 wherein the third laminate comprises a laminar polymer element having two conductive surfaces.
13. The process according to claim 1 , wherein electrical connection is made between conductive surfaces of the first and second laminates in the stack by (i) forming an aperture which extends through the stack, and (ii) forming a conductive member within the aperture.
14. The process according to claim 1 , wherein the electrical connections are positioned so that the individual device comprises at least two electrical connections.
15. The process according to claim 1 , wherein the laminar polymer element in at least one of the laminates comprises a PTC conductive polymer composition.
16. The process according to claim 15 , wherein the laminar polymer element in each laminate comprises the same PTC conductive polymer composition.
17. The process according to claim 15 , wherein the laminar polymer element in each laminate comprises a different PTC conductive polymer composition.
18. The process according to claim 1 wherein the assembly comprises three laminates, each of which comprises a PTC conductive polymer composition.
19. The process according to claim 1 , wherein at least one of the laminar polymeric elements comprises a ZTC conductive polymeric material or an NTC conductive polymeric material.
20. The process according to claim 1 , wherein at least one of the laminar polymeric elements comprises an insulating polymeric material.
21. The process according to claim 1 , wherein the individual devices are subdivided from the assembly using a saw, a shear, a blade, a wire, a waterjet, a snapping device, a laser, or a combination of these.
22. The process according to claim 1 wherein the conductive surface on each laminate comprises a metal foil.