Many toners use resins which are crosslinked to some degree. These resins are used in toners due to the fusing latitude they impart to the toner. These partially crosslinked or “gel” type resins are relaxed in the melt mixing step used to prepare the toner, thus their properties are different from the “as manufactured material”. We have studied the relaxation of the polymeric structure in a gel resin using a Haake batch mixer to simulate the melt mixing step. Resin samples were compared using a Shimadzu CFT-500C flow tester and a Rheometrics RMS Rheometer. Our data show that the properties of the resulting polymer are a function of the shear experienced by the polymer during the melt mixing step. The temperature at which the melt mixing step is performed appears to be the dominant variable influencing the shearing of the polymer.
Edward M. Wilkowski, "Melt Relaxation Studies of Polymeric Structures in Gel-type Toner Resins" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP14), 1998, pp 345 - 348, https://doi.org/10.2352/ISSN.2169-4451.1998.14.1.art00004_2