New Method of Evaluating the Flow Properties of Thickening Agents
2013.09.06 A&D Company, Limited
1 1) Introduction
In recent years, the number of places where viscosity has started to be evaluated has increased.
Viscosity measurement of blood or bile
Viscosity measurement to decide the drinking sensation in the throat from soft drinks
Viscosity measurement relating to eating or swallowing ⇒ possibly triggering pneumonia in the elderly Viscosity of food products is an influence Viscosity management at care facilities or the performance of commercially available thickening agents are problems that have arisen recently
2 2) Aim of new product development
Thickening agents: Xanthane gum CMC (carboxymethyl cellulose) HPC (hydroxypropylcellulose) Lecithin
A rheometer is proposed as a new tool for evaluating these and other agents
3 3) Measurement principles Theoretical model Rz is the mechanical impedance the sensor plates receive from the liquid
z πfAR f: vibration frequency (Hz), A: surface area of both sides of the sensor plates, η: viscosity of liquid, ρ: density of liquid
If the force by which the electromagnetic driver gives the fixed vibration velocity Veiωt to the sensor plates is stated as F: F R πfA z Ve ti
The force generated by the electromagnetic driver is proportional to the product of viscosity η and density ρ. F generated by the electromagnetic driver is found with the following formula:
lBIF I: drive current (A), B: density of magnetic flux (T), l: coil length (m)
4 4) Product appearance and sensor specifics
RV-10000
Constant heat water tank Anti-vibration table Enlargement of sensor unit
5 5) Static viscosity
① Capillary viscometers: Kinetic viscosity = Viscosity / Density
② Rotational viscometers: Viscosity
③ Vibro viscometers Static viscosity = Viscosity × Density
6 6) Product Specifications
Measurement method Tuning fork vibro method/natural frequency 30Hz Amplitude range 0.07mm to 1.2mm (at tip of fork) Viscosity Amplitude (at tip) Viscosity range measurement range 0.07mm 2,000 to 25,000 mPa•s 0.1mm 20 to 25,000 mPa•s 0.2mm 0.3 to 25,000 mPa•s 0.4mm 0.3 to 12,000mPa•s 0.6mm 0.3 to 5,000 mPa•s 0.8mm 1.0mm 0.3 to 3,000 mPa•s 1.2mm Temperature 0 to 160°C measurement range Temperature 0 to 20°C : ±1°C measurement 20 to 30°C : ±0.5°C accuracy 30 to 100°C : ±2°C 100 to 160°C : ±4°C
7 7) RV10000: Relationship between viscosity measurement range and shear rate
Repetitive vibration in a sine wave is induced on the oscillators (sensor plates). The shear rate for vibro visocometers is calculated and notated as an effective (RMS) value. 8 8) RV10000: Relationship between viscosity value and shear rate
9 9) Test results 1. Xanthane gum
(1) Density and viscosity/non-Newtonian 2013.08.2 Controlled at 25℃ using a water jacket 1% viscosity 3% viscosity 5% viscosity 10% viscosity 5mm from the wall 13ml glass cup used
5000 3915mPa.s/10%
3579mPa.s/10%(-8.6%) 4000
3000 X 39
2000
Viscosity (mPa.s) Viscosity 939mPa.s/5% 708mPa.s/5%(-24.6%) 1000
316mPa.s/3% 270mPa.s/3%(-14.6%) 0 108mPa.s/1% 74mPa.s/1%(-31.2%)
0 0.2 0.4 0.6 0.8 1 1.2 Amplitude (mm)
10 9) Test results 2. CMC (Carboxymethyl cellulose)
2013.08.21 (2) Density and viscosity/CMC Controlled at 25 ℃ using a viscosity 1% Viscosity 3% Viscosity 5% Viscosity 10% water jacket 5mm from the wall 12000 13ml glass cup used 11000 10707mPa.s/10% 10000 10533mPa.s/10%(-1.6%) 9000 X 250 8000 7000 6000 5000 4000 Viscosity (mPa.s) 3000 2070mPa.s/5% 2004mPa.s/5%(-3.2%) 2000 1000 483mPa.s/3% 463mPa.s/3%(-4.2%) 0 0 0.2 0.4 0.6 0.8 1 1.2 44mPa.s/1% 42mPa.s/1%(-4.1%) Amplitude (mm)
11 9) Test results 3. HPC (Hydroxypropyl cellulose)
2013.08 Specified viscosity (3) Relationship of molecular mass and viscosity/HPC Controlled at ℃25 using a Molecular weight 2.0 to 2.9mPa.s/molecular weight 40,000 water jacket (GPC method) 6.0 to 10.0mPa.s/molecular weight 140,000 5mm from the wall 1000 to 5000mPa.s/molecular weight 910,00013ml glass cup used
500
400 272.00mPa.s/1000 to 5000mPa.s 267.66mPa.s(-1.6%) 300
200 X 100 Viscosity (mPa.s) Viscosity
100 6.37mPa.s/6.0 to 10.0mPa.s 6.41mPa.s(+0.6%) 2.22mPa.s/2.0 to 2.9mPa.s 2.25mPa.s(+1.4%) 0
0 0.2 0.4 0.6 0.8 1 1.2
Amplitude (mm)
12 9) Test results 4. Lecithin
(4) Relationship of temperature and viscosity/Soy lecithin 2013.08.28 Controlled using a Temperature 25℃ Temperature 30℃ Temperature 45℃ water jacket 5mm from the wall 13ml glass cup used
12000 10217mPa.s/25℃ 9888mPa.s(-3.2%) 11000 10000 -9%/℃ 9000 6935mPa.s/30℃ 8000 6805mPa・s(-1.9%) 7000 6000 -10%/℃ 5000 4000 2731mPa.s/45℃ 2734mPa.s(+0.1%) Viscosity (mPa.s) Viscosity 3000 2000 1000 0
0 0.2 0.4 0.6 0.8 1 1.2 Amplitude (mm)
13 9) Test results 5. Moisturizing skincare cream
14 9) Test results 6. Cornstarch
(5) Measurement example of a Dilatant fluid - 1
Corn starch solution 2500
2000
s） Concentration 62% · (mass proportion)
mPa 1500 （
1000 Viscosity 500 Concentration 60% (mass proportion) 0 0 0.2 0.4 0.6 0.8 1 1.2 Amplitude (mm)
15 9) Test results 7. Fresh cream
(5) Measurement example of a Dilatant fluid - 2 2013.06.27 Controlled at 5℃ using a water jacket Fresh cream 36% fat 5mm from the wall Viscosity 13ml glass cup used 28 26 24 22 20 17.89mPa.s(+94.2%) 18 16 14 Viscosity (mPa.s) Viscosity 12 9.21mPa.s 10 8
0 0.2 0.4 0.6 0.8 1 1.2
Amplitude (mm)
16 10) Conclusion Measurement results for each thickening agent The difference in viscosity value attributable to the difference in density was confirmed in a short amount of time. In particular, the increase in viscosity for CMC when the density rose was striking. A drop in viscosity could be seen in typical thickeners with a rise in shear rate, though they had weak non-Newtonian properties. It became clear that HPC was a Newtonian fluid. The results of the testing also revealed that the viscosity value of the high viscosity sample given by tuning fork method was incongruent with the nominal value. It was revealed that the viscosity of lecithin dropped approx. 10% with every 1°C rise in temperature. Non-Newtonian properties could also be seen with higher shear rate x lower temperature. An increase in the viscosity value by raising the shear rate was confirmed in the cornstarch solution and fresh cream.
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