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Brookfield DV3T Rheometer User Manual

Page 84

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Brookfield Engineering Labs., Inc.

Page 84

Manual No. M13-2100

An Example of the Power Law Model at Work

Formulators at a personal care company

would like to use a substitute ingredient to

decrease cost. They use the Power Law model

to evaluate the effect the new ingredient

will have on the behavior of their shampoo.

They need to know how it will behave during

processing and how it will behave when it is

being used be the consumer

With the new ingredient the shampoo has a flow index (

n) of 0.08. This indicates that the

shampoo is shear-thinning enough to flow properly during processing and that it will flow

properly for the end-user. The consistency index,

k, indicates how the shampoo behaves

when it experiences low shear rates. The power law values show that the shampoo becomes

quite thin at process shear rates and therefore it can be easily pumped into filling equipment,

hold tanks, etc. The consistency index of 91,071 cP shows that the shampoo is very viscous

at low shear rates, and as a result, it will appear to customers to be “rich and creamy” while

still being easy to apply.

Shampoo

Flow Index (

n) = 0.08

Consistency Index (

k) = 91071 cP