GB/T 15357-2014Surface active agents and detergents -- Determination of viscosity and flow properties of liquid products using a rotational viscometer (English PDF)

1 Scope

This standard specifies a general method for determining the viscosity and flow properties of surface-active agent and detergent liquid products using a rotational viscometer.

This standard applies to samples with a viscosity of 5 mPa · s~5×10^4 mPa · s. For

Newtonian samples with a viscosity below 5 mPa · s, a more precise method, such as a capillary viscometer, shall be used.

2 Normative references

The following documents are essential for the application of this document. For any dated reference, only the version corresponding to that date applies to this document;

for any undated reference, the latest version (including all amendments) applies to this document.

GB/T 13173-2008 Surface active agents - Detergents - Testing methods

JJG 1002 Rotational Viscometers

3 Terms and definitions

The following terms and definitions apply to this document.

3.1 dynamic viscosity

A measure of the internal frictional force when one liquid layer flows relatively to another under a certain shear stress. It is the ratio of the shear stress (tau), and the shear rate (D) applied to the flowing liquid, expressed in Pascal second (Pa · s) or millipascal second (mPa · s)1). It is represented by Newton's equation.

1) The units of dynamic viscosity also include newton second per square meter (N · s/m2), millinewton second per square meter (mN · s/m2), and poise(P) and centipoise(cP). 1 N · s/m2=1 Pa · s=10 P(poise)=103 cP(centipoise), 1 mN · s/m2=1 mPa · s=1 cP(centipoise).

3.8 thixotropy

Under isothermal reversible conditions, shearing causes viscosity or consistency to decrease from its rest value (the instant shearing begins) to its final value (depending on the magnitude of the shear rate). When shearing is interrupted, the rest viscosity or consistency must recover within a certain time; this time is called the thixotropic recovery time.

3.9 rheopexy

The phenomenon in which the thixotropic recovery time is shortened by a lower shear rate after a relatively high shear rate interruption.

3.10 anti-thixotropy

Under isothermal reversible conditions, the viscosity or consistency increases from its rest value (the instant shearing begins) to its final value (depending on the magnitude of the shear rate) due to shearing action.

When shearing is interrupted, the rest viscosity recovers within a certain time; this time is called the thixotropic recovery time.

3.11 rheological hysteresis

Under isothermal reversible conditions, if the shear rate increases linearly from zero to a maximum value (upward line) over time and then decreases in the same way (downward line), the shear rate plot presents a hysteresis loop, which can be used to detect and characterize thixotropy or anti-thixotropy.

3.12 plasticity

When a plastic body is subjected to a stress less than the critical value tau0, the "yield stress", it behaves as an elastic body. Above this limit, flow occurs. When tau>=tau0 and the function D=f(tau) is linear, the material can be said to follow the Bingham model.

3.13 time-dependent viscosity

Under isothermal reversible conditions and at a constant shear rate, the apparent viscosity changes with time.

4 Principle

At a specified shear rate, the dynamic viscosity of Newtonian liquids or the apparent viscosity of non-Newtonian liquids is measured using a specified rotational viscometer.

The shear rate is used as the variable for the determination, and the liquid properties are represented by plotting a relationship curve between the shear rate and the shear stress or viscosity.

5 Apparatus

6 Procedure