DeterminationofViscosityUsingABrookfieldViscometerforConditioningPolymers

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LUBRIZOL TEST PROCEDURE 
 
 
 
TP-N01004 
Edition: December 2, 2013 
Previous Editions: August 10, 2000 / November 1, 2011 
 
 
Determination of Viscosity Using A Brookfield 
Viscometer for Conditioning Polymers 
 
 
 
Scope 
 
A material's flow property is an important in-process 
and finished product parameter. It may be an 
indicator of a product's performance in a coating 
operation, its penetrating ability or ease of handling 
or use. The interrelationship between viscosity and 
other physical characteristics of a product e.g., 
color, solids content, etc., are useful indicators of 
product quality, acceptance and performance. 
 
Theory 
 
Viscosity is the measure of the internal friction of a 
fluid. This friction becomes apparent when a layer of 
fluid is made to move in relation to another layer. 
The greater the friction, the greater the amount of 
force required to cause its movement, which is 
called "shear". Shearing occurs whenever the fluid 
is physically moved as in pouring, mixing, etc. The 
measure of the speed at which these layers move 
with respect to each other is called the "shear rate." 
This has a unit of measurement called the 
"reciprocal second" (sec-I). Highly viscous materials 
thus require more force to move than less viscous 
materials. The force per unit area required to 
produce shearing action is called "shear stress." It 
has a unit of measure called "dynes per square 
centimeter" (dynes/cm2). Viscosity (n) can then be 
described by the following equation: 
 
shear stress 
n = ------------------- 
shear rate 
 
The fundamental unit of viscosity measurement is 
the "poise." A material requiring a shear stress of 
one dyne per square centimeter to produce a shear 
rate of one reciprocal second has a viscosity of one 
poise (P), or 100 centipoise (mPa·s). For this 
method, the units reported will be centipoise 
(mPa·s). The Brookfield viscometer rotates a disc 
or cylinder in a fluid sample and measures the 
torque needed to overcome the viscous resistance 
to the induced movement. This is done by rotating 
the spindle with an electric motor, through a 
beryllium-copper spring. The degree to which the 
spring is wound, measured by a deflection of a 
needle on the viscometer's dial, is proportional to 
the viscosity of the fluid. For precision measure-
ments between 0 and 100 centipoise, the UL 
Adapter is used in conjunction with the viscometer. 
 
It is important at this time to discuss Newtonian and 
non-Newtonian fluids. 
 
A Newtonian fluid is a material which has, at a 
given temperature, a viscosity which is independent 
of the shear rate. In other words, when the "shear 
rate" is varied, the "shear stress" varies in the same 
proportion. Typical Newtonian fluids include water 
and thin motor oil. The Brookfield Viscosity 
Standards are also Newtonian fluids. 
 
In a non-Newtonian fluid, when the "shear rate" is 
varied, the "shear stress" doesn't vary in the same 
proportion or even necessarily in the same 
direction. The viscosity of such fluids will change 
as the shear rate is varied. The most common 
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Lubrizol Test Procedure TP-N01004 
Determination of Viscosity Using a Brookfield 
Viscometer for Conditioning Polymers 
Page 2 of 5 
 
 
type of non-Newtonian fluids are called Pseudo-
plastic (the viscosity decreases as the "shear rate" 
increases), Dilatent (viscosity increases as the "shear 
rate" increases), and Plastic (this type of fluid will 
behave as a solid under static conditions). The most 
common non-Newtonian fluids (paints, emulsions 
and dispersions) are of the Pseudoplastic type. 
 
Some non-Newtonian fluids display a change in 
viscosity with time under constant shear rate. There 
are two categories of this type of fluid: Thixotropic 
(the fluid's viscosity decreases with time as it is 
sheared at a constant rate); and Rheopectic (the 
fluid's viscosity increases with time as it is sheared at 
a constant rate). 
 
The information in this section is taken from "MORE 
SOLUTIONS TO STICKY PROBLEMS" BROOK-
FIELD ENGINEERING LABORATORIES, INC. 
Stoughton, Massachusetts. 
 
Equipment 
 
1. Brookfield Viscometer with UL Adapter, Model 
LVF, or equivalent, or as specified in Routine 
Product Control or Corporate Routine Raw 
Material Control. 
 
2. Mercury immersion thermometer, glass, 0° to 
220°F graduated in at least 2°F increments, or 
equivalent temperature indicator. 
 
3. Constant temperature water bath or an 
equivalent system for adjusting the 
measurement temperature of a sample. 
 
4. Griffin beakers, 600 mL, or larger, or any similar 
container with a minimum inside diameter of 3 1/4 
inches (83 mm). Containers of other sizes may be 
required by Routine Product Controls, Corporate 
Routine Raw Material Controls, an addendum, or 
a Site Specific SOP or Policy. 
 
5. Brookfield FACTOR FINDER (contains conver-
sion factors to convert dial readings to viscosities 
in centipoise (mPa·s). 
 
Reagents 
 
1. Various Brookfield Viscosity Standards (such as 
nominal 5, 10, 100, 1000, 5000, 12500 mPa·s), 
or equivalent with NlST Traceable Certificates 
of actual analysis. 
2. For Merquat™ 2200 polymer: 
 a. Obazoline 662N. 
 b. Deionized water. 
 
Method Standardization 
 
1. Refer to Site SOP or Site Calibration 
Procedure. 
 
Instrument Operating Conditions 
 
1. lnstrument Operating Conditions will vary 
depending on the Model (Analog or Digital). 
Refer to Site SOP or lnstrument Operation 
Manual for current lnstrument Operating 
Conditions. 
 
2. The Viscometer must be level and the spindle 
suitably centered in the test sample container. 
 
3. The spindle must be properly immersed to the 
groove found on its shaft. 
 
a. To prevent the formation of bubbles under 
and around the spindle, the spindle should 
be immersed into the sample at a slight 
angle before attaching to the viscometer. 
This is especially true for viscous materials.b. All Brookfield Viscometers are calibrated at 
the factory. The calibration of all Brookfield 
Viscometers is based on immersion of the 
spindle in a 600 cc low form Griffin beaker 
(approximately 3 1/4" internal diameter). 
Viscometer ranges will generally change if 
smaller vessels are used. They will also 
change as the spindle is brought near the 
walls of the container. Guard legs must be 
attached if furnished FACTOR FINDER is 
used, particularly with the first two spindles 
(#1 and #2). 
 
 c. The use of a container smaller than the 600 
ml low form Griffen beaker will result in an 
increase in viscosity readings, particularly 
with the #1 and #2 spindles. 
 
 
Lubrizol Test Procedure TP-N01004 
Determination of Viscosity Using a Brookfield 
Viscometer for Conditioning Polymers 
Page 3 of 5 
 
 
d. If specified, use a container smaller than the 600 
ml Griffen beaker, the simplest approach is to 
report the dimensions of the container and ignore 
the probable effect on calibration. As long as 
the same size container is used for all 
subsequent test, there will be no correlation 
problem. Alternately, the viscometer can be 
recalibrated to compensate for the smaller 
container. 
 
Procedure 
 
1. Consult the Product Specifications for the proper 
model spindle number, speed of rotation (rpm), 
sample size, sample temperature and, if 
necessary, the container size. If not stated there, 
determine the sample viscosity at the highest 
speed of rotation which will give a reading toward 
full scale. (The precision of the instrument 
increases at this end of the scale). 
 
2. Unless otherwise specified, transfer approximate-
ly 400 mL of sample to a 600 mL beaker and 
adjust sample to the required measurement 
temperature. Unless otherwise specified on the 
Product Specification, this temperature adjust-
ment should be done to within +I°C or +2°F. Use 
a water bath, if necessary. 
 
3. Insert spindle in the test material until the fluid's 
level is at the immersion groove cut in the 
spindle's shaft. With disc type spindles, care 
should be taken to avoid trapping air bubbles on 
its surface. Tilt the beaker while immersing the 
spindle or immerse spindle at an angle before 
attaching to the viscometer. 
 
4. Thread spindle to the instrument shaft in a 
clockwise direction. Finger tighten the connection. 
 
5. Position the sample so that the spindle is 
centered in the test sample container. The 
Brookfield factory calibration procedure uses 
guard legs. Unless the instrument has been 
recalibrated without the guard legs or the guard 
legs are not required by Site Specific SOP or 
Policy, it will be necessary to use guard legs for 
viscosity measurements. 
 
6. Check the level of the viscometer with the 
bubble level. For accurate results, it is very 
important that the leveling bubble is exactly 
centered. 
 
7. Unless otherwise instructed, take a reading 
when the pointer or the digital display is stable. 
Record this reading, and, if necessary, consult 
the Factor Finder to obtain the proper factor for 
the viscometer model, speed and spindle 
number that was used. 
 
a. The viscosity specification itself must be 
met and reported using the speed, spindle, 
and temperature listed in the appropriate 
document. Any viscosity measurement not 
meeting these requirements (spindle, speed 
and temperature) will be deemed off-spec. 
 
b. If the viscosity measurement is off-scale 
high, go to the next higher spindle number 
but do not change the rpm setting. If the 
viscosity measurement is off-scale low, go 
to the next lower spindle number but do not 
change the rpm setting. This is for reporting 
purposes only. The measured value will be 
considered out of specification even if the 
measured value lies within the specification 
range when using different spindle and/or 
speed. 
 
 
 
 
 
 
Lubrizol Test Procedure TP-N01004 
Determination of Viscosity Using a Brookfield 
Viscometer for Conditioning Polymers 
Page 4 of 5 
 
 
8. UL Adapter - If specified, the UL Adapter (1-100 
mPa·s) must be installed following the instruction 
in the lnstrument Operations Manual. 
 
a. Two UL Adapter tubes are available, an open 
tube for measurements in tanks or beakers 
and a closed tube which holds 16.0 mls of 
sample. The open tube can be converted to a 
closed tube using a plastic end cap provided 
by Brookfield. The closed tubes can be 
immersed in a constant temperature bath. 
When using an open tube, immerse to the 
groove in the side of the UL Adapter. 
 
NOTE: Check the operating instructions for the 
model used for the current UL Adapter equipment 
available. This will also give the correct sample size 
for measuring viscosity on a UL Adapter. 
 
9. Adjust viscometer to the proper rpm setting as 
stated in the appropriate document. When using 
the UL Adapter, the proper rpm setting is 
determined by the expected viscosity range of the 
sample: 
RPM Range (mPa·s) 
60 0 - 10 
30 0 - 20 
12 0 - 50 
6 0 - 100 
 
10. If the UL Adapter was used on the Analog 
Viscometer, obtain appropriate factor from the 
following chart. This factor compensates for the 
windage resistance encountered by the needle 
indicate. THIS MAY NOT APPLY TO THE 
MODELS WITH A DIGITAL READOUT. CHECK 
THE OPERATING INSTRUCTIONS FOR THE 
MODEL USED. 
 
Multiply scale reading by this factor to get correct 
viscosity. 
RPM Range (mPa·s) Factor 
60 0 - 10 0.1* 
30 0 - 20 0.2** 
12 0 - 50 0.5 
 6 0 - 100 1.0 
 
 * Deduct 0.4 from reading off 100 scale before multiplying 
to correct for air resistance to rotation at 60 rpm. 
 
**Deduct 0.1 from reading off 100 scale before multiplying 
to correct for air resistance to rotation at 30 rpm. 
11. If the UL Adapter dial reading is off-scale high, 
go to the next lower rpm setting. The UL 
Adapter is supplied with one spindle. 
12. For Merquat™ 2200 polymer: 
 a. Pour 380 g of deionized water into a 600 ml 
beaker. 
 b. Add 20 g of Merquat 2200 while stirring the 
solution with a propeller-type stirrer. Mix for 
1 hour. 
 c. Add 100 g of Obazoline 662N and mix for 
30 minutes. 
 d. Measure the solution viscosity at 30°C using 
a Brookfield viscometer, spindle #2 at 12 
rpm. 
 
Calculation and Data Reporting 
 
1. Report viscosity, temperature, spindle number 
and speed of rotation used. Remember that 
the speed and spindle values as well as the 
measurement temperature are part of the 
product or raw material specification. For a 
viscosity measurement to be in specification, it 
must be made at the speed, spindle and 
temperature specified. It is possible, therefore, 
to have a viscosity measurement which meets 
the centipoise range but be off spec if the 
wrong spindle and speed have been used in 
the measurement of that value. 
 
2. Viscosity in mPa·s = Dial Reading x Factor. 
Newer models (Digital) can be programmed to 
read viscosity directly. 
 
Performance Data 
 
1. Range: 0 - 100,000 mPa·s. 
 
2. Accuracy: The results obtained agree with 
theoretical to within 1%. Brookfield viscome-
ters are guaranteed to be accurate to within 
+I% of its full scale range. 
 
3. Precision: The original performance data is 
based on duplicate analyses of five samples 
performed by each of three operators. Pooled 
Standard Deviation: 27.21 mPa·s. Therefore, 
the precision without the UL adapter is 
estimated to be 282 mPa·s. 
 
 
 
 
Lubrizol Test Procedure TP-N01004 
Determination of Viscosity Using a Brookfield 
Viscometer for Conditioning Polymers 
Page 5 of 5 
 
 
The standard deviation using the UL Adapter is 
0.019 mPa·s as determined by one operator on 
one sample of a Newtonian fluid (average 4.81 
mPa·s) with a total of nine replicates yielding 
eight degrees of freedom. The precision of the 
test method is three times the standard deviation 
and therefore estimated to be plus or minus 0.057 
mPa·s. The method has percent relative standard 
deviation (%RSD) of 1.2%. 
 
The standarddeviation using a #2 spindle at 30 
rpms is 1 .I3 mPa·s as determined by one 
operator on one sample of a Newtonian fluid 
(average 951.4 mPa·s) with a total of nine 
replicates yielding eight degrees of freedom. The 
precision of the test method is three times the 
standard deviation, and therefore, estimated to be 
k3.39 mPa·s. The method has percent relative 
standard deviation (%RSD) of 0.36%. 
 
4. Detection Limit: If you chose a spindle and speed 
such that your full scale range is 0-1 00 mPa·s, 
the Viscometer will measure any viscosity in this 
region to 1.0 mPa·s. 
 
5. Elapsed Time: 10 minutes 
 
6. Operator Time: 10 minutes 
 
References 
 
See Restricted Page. 
 
1. F. Daniels, R. A. Alberty, PHYSICAL CHEMISTRY, 
4th Edition, John Wiley & Sons, lnc., NY, 1975 
 
2. "Brookfield Synchro-Lectric Viscometer Instruction 
Manual". 
 
3. “More Solutions to Sticky Problems, A Guide To 
Getting More From Your Brookfield Viscometer”, 
Brookfield Engineering Labs, Inc. 
 
4. Brookfield Engineering Laboratories Data Sheet 
034-c, The Brookfield U.L. Adapter. 
 
5. Brookfield Engineering Laboratories maintains a 
library of technical papers on viscosity 
measurement and control. Reprints are available 
upon request at no charge. A current listing of 
available papers and an order form are provided in 
the booklet, TECHNICAL PAPERS ON 
VISCOSITY MEASUREMENT AND CONTROL 
(Data Sheet 091-C). 
 
	Determination of Viscosity Using A Brookfield
	Viscometer for Conditioning Polymers