US 12,064,925 B2
Fiber-reinforced composite laminate for use in electromagnetic welding and method of electromagnetic welding of molded parts of said laminates
Maarten Labordus, The Hague (NL); Tom Jansen, The Hague (NL); Michiel Hendrik Paul Bruijkers, The Hague (NL); Thomas Wirtz, The Hague (NL); Alexandros Michaïl Mitrousias, The Hague (NL); and Sacha Schmitter, The Hague (NL)
Assigned to KOK & VAN ENGELEN COMPOSITE STRUCTURES B.V., The Hague (NL)
Appl. No. 17/920,976
Filed by KOK & VAN ENGELEN COMPOSITE STRUCTURES B.V., The Hague (NL)
PCT Filed Apr. 30, 2021, PCT No. PCT/NL2021/050286
§ 371(c)(1), (2) Date Oct. 24, 2022,
PCT Pub. No. WO2021/221510, PCT Pub. Date Nov. 4, 2021.
Claims priority of application No. 2025473 (NL), filed on Apr. 30, 2020.
Prior Publication US 2023/0166458 A1, Jun. 1, 2023
Int. Cl. B32B 5/26 (2006.01); B29C 65/00 (2006.01); B29C 65/38 (2006.01); B32B 5/02 (2006.01)
CPC B29C 65/38 (2013.01) [B29C 66/7212 (2013.01); B32B 5/028 (2013.01); B32B 5/26 (2013.01); B32B 2262/106 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A fiber-reinforced composite laminate for use in electromagnetic welding of molded parts of said laminates, the laminate comprising a plurality of structural layers, each formed of electrically conductive fibers embedded in a thermoplastic matrix, wherein eddy currents may be induced in the electrically conductive fibers by an electrical conductor that generates an electromagnetic field;
wherein the plurality of structural layers comprises a first, a second and, optionally, a third pair of two adjacently positioned structural layers, wherein:
the first pair has an intermediate layer positioned in between the two structural layers of the pair, wherein the intermediate layer has an out-of-plane electrical volume resistance R1, which substantially allows eddy currents to flow between the two structural layers of the first pair;
the second pair has an intermediate layer positioned in between the two structural layers of the pair, wherein the intermediate layer has an out-of-plane electrical volume resistance R2, which substantially prevents eddy currents from flowing between the two structural layers of the second pair; and
the optional third pair does not have an intermediate layer in between the two structural layers of the pair;
wherein:
R1 and R2 are finite and 0<R1<R2;
the intermediate layer in each first and second pair differs from the two structural layers in each first and second pair in that the intermediate layer in each first and second pair does not comprise the electrically conductive fibers; and
the condition R1<R2 is achieved by having p1·t1<p2·t2 wherein p1 is the electrical volumetric resistivity of the material of the intermediate layer in the first pair, t1 is the average thickness of the intermediate layer in the first pair, p2 is the electrical volumetric resistivity of the material of the intermediate layer in the second pair, and t2 is the average thickness of the intermediate layer in the second pair.