Materials that are thixotropic have a time-dependent, shear-thinning viscosity. In other words, as the material is placed under stress to flow, the longer the stress is applied, the lower the viscosity will be.
Thixotropy can be quantified as the “thixotropic index” of a material. The thixotropic index is a ratio of the viscosity of a material at two different shear rates (low-shear viscosity/high-shear viscosity). The low-shear rate and high-shear rate are typically different by a factor of 10. For example, if the viscosity at 1 rpm is 20,000 cPs and the viscosity at 10 rpm is 5,000 cPs, then the thixotropic index of that material is 4.
Thixotropy is important for applications that require the material to flow easily during dispensing but then must stay in place once they are dispensed. This allows materials to be dispensed in exact patterns and shapes without any sagging or slumping after application.
For more than half a century we have been developing and manufacturing high-performance adhesive products. Our adhesive product lines include various thixotropic, non-sag solutions that perform in applications ranging from industrial structure to automotive assembly-to-repair.
We specialize in developing world-class thermal management, potting and encapsulation, gap filling, semiconductor packing, adhesive and thick film materials for demanding applications. Our Electronic Materials product line includes solutions that have thixotropic characteristics and rheology, allowing their shape to be maintained (minimal flow) after dispensing.