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Viscosity

Link to relevant study record(s)

Reference

Endpoint:

viscosity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 18 October 2012 to 18 December 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with international standard guidelines under GLP conditions. The study report was well documented with all mandatory information included

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Test Guideline 114 (Viscosity of Liquids)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

11-04-11

Type of method:

other: rolling ball viscometer

Temp.:

other: 19.98°C

Parameter:

dynamic viscosity (in mPa s)

Value:

> 24.128 - < 24.168

Temp.:

40°C

Parameter:

dynamic viscosity (in mPa s)

Value:

> 9.63 - < 9.641

Temp.:

other: 19.98°C

Parameter:

kinematic viscosity (in mm²/s)

Value:

> 21.764 - < 21.8

Temp.:

40°C

Parameter:

kinematic viscosity (in mm²/s)

Value:

> 8.686 - < 8.697

All measured values and the corresponding calculation results are given in the following table:

	Determination at 40 °C
	Temperature	Falling Time		Total Time
Measurement		Time [min]	Time [s]	Total Time [s]	Viscosity [mPa*s]
No. 1	40.00	1	50.81	110.81	9.6418
No. 2	40.00	1	50.72	110.72	9.6340
No. 3	40.00	1	50.68	110.68	9.6305
Mean				110.74	9.6354
Standard Deviation				0.07	0.0058
RSD					0.06%
	Determination at 20 °C
	Temperature	Falling Time		Total Time
Measurement		Time [min]	Time [s]	Total Time [s]	Viscosity [mPa*s]
No. 1	19.98	4	37.34	277.34	24.1320
No. 2	19.98	4	37.44	277.44	24.1407
No. 3	19.98	4	37.78	277.78	24.1702
Mean				277.52	24.1476
Standard Deviation				0.23	0.0201
RSD					0.08%

Calculation of Dynamic Viscosity

For each measurement, the dynamic viscosity of the test item was calculated using the following equation:

n = K* (p₁ -p₂)*t

with

n  = dynamic viscosity in mPa * s
K = constant of ball used in mPa * s * cm³/(g*s)

p₁  = density of ball used in g/cm³
p₂ = density of test item in g/cm³
t = falling time for the ball in s

Parameters of ball used are given in the table below:

Material	Density (g/cm^3)	Diameter (mm)	Minimum Falling Time (s)	Constant k [  mPa * s * cm^3/(g*s)]	Measuring range (mPa*s)
Borosilicate glass	2.231	15.636	30	0.07752	3 - 30

Calculation of kinematic viscosity:

The kinematic viscosity of the test item was calculated using the following equation:

v = n /p₂

with

v = kinematic viscosity in mm²/s

n = dynamic viscosity in mPa*s

p₂= density of test item in g/cm³ (1.1086 g/cm³ at 20°C)

Results:

Results of the single determinations with the respective standard deviation as well as the mean value and the standard deviation of all six individual experiments are presented in the following table:

	Experiment 1 at 40 °C	Experiment 2 at 20 °C
Determination	Dynamic Viscosity in mPa*s	Dynamic Viscosity in mPa*s
1	9.6418	24.1320
2	9.6340	24.1407
3	9.6305	24.1702
Mean	9.6354	24.1476
Standard Deviation	0.0058	0.0201
RSD	0.06%	0.08%
	Kinematic Viscosity in mm²/s	Kinematic Viscosity in mm²/s
Mean	8.6915	21.7821
Standard Deviation	0.0052	0.0181

The mean of each series of three measurements was calculated. The allowed maximum deviation is given in the following table:

Ball #	RSD in %
2, 3	0.5

As the measured RSD were 0.06 % at 40.00 °C and 0.08 % at 19.98 °C, the validity criterion is met.

The dynamic viscosity of an aqueous solution of test item was determined as 24.1476± 0.0201 mPa *s at 19.98 °C and 9.6354 ± 0.0058 mPa *s at 40.00 °C. These values correspond to a kinematic viscosity of 21.7821 ± 0.0181mm²/s at19.98 °C and 8.6915 ± 0.0052mm²/sat 40.00 °C).

Both dynamic viscosity values are the mean of three individual measurements. Precision of each value is given as standard deviation of the individual measurements. As the measured RSD were 0.08 % (19.98 °C) and 0.06 % (40.00 °C), the validity criterion (RSD < 0.5 %) is met.

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Conclusions:

The dynamic viscosity of the test item was determined as 24.1476 ± 0.0201 mPa *s at 19.98 ± 0.1 °C and 9.6354 ± 0.0058mPa *s at 40.0 ± 0.1 °C (corresponding to a kinematic viscosity of 21.7821 ± 0.0181mm²/s at 19.98± 0.1 °C and 8.6915± 0.0052 mm²/s at 40.0 ± 0.1 °C).

Executive summary:

The determination of viscosity was performed with a rolling ball viscometer according to Method 114 of OECD Guidelines for Testing of Chemical 12 May 1981 and GLP. No deviation form the Guideline was observed during the test.

The dynamic viscosity is calculated from the falling time of a ball with known density and constant k in a calibrated rolling ball viscometer following Hoeppler and the density of the test item.

The dynamic viscosity of the test item was determined as 24.1476 ± 0.0201 mPa *s at 19.98 ± 0.1 °C and 9.6354 ± 0.0058mPa *s at 40.0 ± 0.1 °C (corresponding to a kinematic viscosity of 21.7821 ± 0.0181mm²/s at 19.98± 0.1 °C and 8.6915± 0.0052 mm²/s at 40.0 ± 0.1 °C).

Description of key information

Experimental value of viscosity: 24.1476 ± 0.0201 mPa *s at 19.98 ± 0.1 °C and 9.6354 ± 0.0058mPa *s at 40.0 ± 0.1 °C (corresponding to a kinematic viscosity of 21.7821 ± 0.0181mm²/s at 19.98± 0.1 °C and 8.6915± 0.0052 mm²/s at 40.0 ± 0.1 °C).

Key value for chemical safety assessment

Viscosity:

21.782 mm²/s (static)

at the temperature of:

20 °C

Additional information

The experimental determination of viscosity was performed with a rolling ball viscometer according to Method 114 of OECD Guidelines for Testing of Chemical 12 May 1981 and GLP. No deviation form the Guideline was observed during the test.