US 12,420,458 B2
Multi-stage pressing process for producing a molded part such as a bipolar plate from a highly filled thermosetting material
Günter Rinn, Lahnau (DE); Hauke Voormann, Linden (DE); Sören Baumann, Gießen (DE); and Mesut Altuntas, Frankfurt (DE)
Assigned to SCHUNK KOHLENSTOFFTECHNIK GMBH, Heuchelheim (DE)
Appl. No. 18/041,280
Filed by SCHUNK KOHLENSTOFFTECHNIK GMBH, Heuchelheim (DE)
PCT Filed Oct. 9, 2020, PCT No. PCT/EP2020/078489
§ 371(c)(1), (2) Date Feb. 10, 2023,
PCT Pub. No. WO2022/037799, PCT Pub. Date Feb. 24, 2022.
Claims priority of application No. 10 2020 121 997.0 (DE), filed on Aug. 21, 2020.
Prior Publication US 2023/0302691 A1, Sep. 28, 2023
Int. Cl. B29C 43/14 (2006.01); B29C 43/34 (2006.01); B29C 43/36 (2006.01); B29C 43/52 (2006.01); B29K 101/10 (2006.01); B29K 105/16 (2006.01)
CPC B29C 43/14 (2013.01) [B29C 43/34 (2013.01); B29C 43/361 (2013.01); B29C 43/52 (2013.01); B29C 2043/143 (2013.01); B29C 2043/3634 (2013.01); B29K 2101/10 (2013.01); B29K 2105/16 (2013.01)] 15 Claims
OG exemplary drawing
 
1. Process for producing an electrically conductive molded part forming a bipolar plate for a fuel cell from a highly filled thermosetting starting material, the process comprising:
introducing the starting material into a prepressing tool, wherein the highly filled thermosetting starting material contains at least one of graphite and other predominantly carbon-containing compounds as filler in the starting materials with a filler content of at least 70 mass percent and wherein the starting material comprises 2-methylimidazole as a curing catalyst operable to accelerate curing of the starting material;
producing a preform from the starting material, wherein the starting material is brought to a prepressing temperature by means of the prepressing tool including a prepressing lower die and a prepressing upper die each having contoured pressing surfaces and is compressed with a prepressing force to form the preform;
removing the preform from the prepressing tool and introducing the preform into a finish pressing tool; and
producing a finished part from the preform, wherein the preform is brought to a finish pressing temperature by means of the finish pressing tool and is compressed with a finish pressing force to form the finished part;
wherein the prepressing temperature is lower than the finish pressing temperature;
wherein the finish pressing temperature is at least as high as an onset temperature of a curing reaction of the starting material.