In heating baths to heat various samples
* While a particular model/version may be used as an example in this method, any current or past model/version from the same series may also be used. Please consult a sales associate to discuss the most current instrumentation and software available.
The test was run at 150°F. We used a Brookfield LVDV-III Ultra digital Rheometer, with SC4-21 spindle and disposable chamber, in a Brookfield Thermosel for controlled elevated temperature measurements. Rheocalc V3.0 software was used for automated instrument control and data acquisition. Representative data from the analyses are shown in Figure 1, below:
Figure 1: Heating Bath Wax behavior at 150°F.
The graph shows a relatively constant viscosity, about 21-22 cP, over the speed range tested. This is “Newtonian” behavior. Since the molten wax is Newtonian, its viscosity could be tested for QA/QC by using a single-speed. Furthermore, this procedure could also be performed with viscometers such as the LVDV-II+Pro and our new LVDV-I Prime, for example. Either one can be used in standalone mode or with software – the LVDV-II+Pro with Rheocalc, and the LVDV-I Prime with Wingather.
The above example is for one type of wax. In this case, the LVDV-III Ultra and SC4-21 spindle provided readings within our recommended 10-100% of full scale range. Polyethylene waxes, on the other hand, may have a significantly higher viscosity. Standard procedure ASTM D 1986 states that polyethylene waxes should be tested using the SC4-31 spindle. That procedure document is available from ASTM International.
The SC4-31 will allow a viscosity range almost seven times higher than that achieved with the SC4-21, using the LV instrument, at the same speed.