This formula works in Excel, assuming no values have commas.
=IFERROR(LEFT(RIGHT(H5, SUM(LEN(H5)-FIND("material=", H5)- LEN("material="), 1)), IFERROR(FIND(",", RIGHT(H5, SUM(LEN(H5)-FIND("material=", H5)- LEN("material="), 1)))-1, LEN(M5RIGHT(H5, SUM(LEN(H5)-FIND("material=", H5)- LEN("material="), 1))))), "")
Just replace H5 and "material" with the appropriate cell and key.