Naked Science Forum

General Science => General Science => Topic started by: ratwing on 06/09/2011 10:46:04

Title: Where can I find the definition of "label claim viscosity"
Post by: ratwing on 06/09/2011 10:46:04
Its in relation to hydroxypropylmethyl cellulose which comes in many different viscosity grades. The question is, is the "label claim viscosity" the nominal value of a grade ie 5cP, or the actual measured value of an individual batch of that particular grade which could be (for example) 5.1cP?
Title: Where can I find the definition of "label claim viscosity"
Post by: damocles on 06/09/2011 13:42:37
Hmm! I would expect the "label claim viscosity", which is not really a defined technical term, to mean the viscosity stated on the label.

A label for a viscosity-dependent product might come in many different forms. It might be very broad and general -- like "5 cP" -- which can only mean that it is around about 5 centipoise at some sort of ambient room temperature (remember that viscosity is highly temperature dependent). Or, in some cases there might be included a batch-specific label: " Batch 2144A; 25 Sep 2010. Viscosity 5.14 +/- 0.10 cP @ 20.0 deg C". Either of these, or anything in between, is quite likely, depending on just how critical the exact viscosity is seen to be for the product application.

The important point is that the label -- any label -- is making a claim about the product. It might be a very weak claim -- " at round about room temperature the viscosity will be round about 5 centipoise" in the first case, or the much stronger and more specific claim of the second case. In either case, there is a "label claim viscosity".