Thixotropy index

Viseosity 6.2.1 Report viseosity and thixotropie index (0.5/5 rpm) ASTM D2556 or other agreed to by vendor and supplier 6.2.1... 

This value is defined as the TI (thixotropy index) which is used as an index for showing the degree of shear rate dependence of conductive paste viscosity. 

Figure 7-5 The relationship between shear rate and viscosity (TI - thixotropy index).

The rheological curves of thixotropic fluids, such as IP 680 in Figure 21, show that there is a yield stress tq to overcome before shear can take place. This phenomenon is taken into account in Casson s model represented by the equation = (tq) - - [tioldy/dt)] , where the yield stress tq is usually determined by extrapolating to zero shear the curve representing the variation of the shear stress at different shear rates. For the sake of convenience, conductive adhesive pastes are often characterized by a thixotropy index, which is the ratio of the viscosities... 

Evans and Caldwell introduced an index called the Blue staining residue (B.s.r.) which is related to the intensity of the color developed by a dextrin with iodine. B.s.r. values decrease together with the thixotropy of gels from dextrins. It should be noted that fatty acids present in the dextrinized starch favor the formation of dextrins having a high B.s.r., that is, dextrins of good thixotropic properties. For studies on a related subject, see an article by Tsuji and Mochizuki. ... 

Thixotropy may also be expressed as the thixotropic index (TI) which is the ratio of viscosities measured at speeds that have a ratio of 1 10 rpm, for example at 2 rpm... 

---