How to measure the viscosity of water-based ink
Date: Jul 26 2024 From: Star Color
The viscosity measurement of water-based ink is an important step in ensuring printing quality and stability. The following are several commonly used methods for measuring the viscosity of water-based inks:
1、 Tu-4 cup viscometer method1.1 Principle
The Tu-4 cup viscometer method characterizes the viscosity of a certain amount of ink sample by measuring the time it takes for the sample to flow out of a hole of a specified diameter at a certain temperature. This method is simple, intuitive, and easy to operate.
1.2. Tools and materials
Tu-4 cup viscometer
Mercury thermometer (temperature range 0-50 ℃, division value 0.1 ℃)
Stopwatch
Measuring cup (with a capacity of 200mL or 100mL, depending on the viscosity meter model)
Glass rod (diameter 7mm, length 250mm)
Cotton yarn
Cleaning solvent (such as alcohol, used to clean the viscometer)
1.3. Inspection steps
Wipe the inner wall and leakage nozzle of the viscometer cup clean, adjust the horizontal spiral of the bracket to make the viscometer in a horizontal state.
Place a measuring cup under the leakage nozzle of the viscometer and reset the stopwatch to zero.
Block the leakage hole with a stopper, pour the ink that has been stirred evenly and adjusted to (25 ± 0.2) ℃ into the viscosity meter cup, and use a glass rod to scrape the bubbles and excess sample into the groove.
Release the stopper and start the stopwatch at the same time. Stop timing when the ink flow is interrupted and the first drop appears. The time indicated by the stopwatch at this time is the viscosity of the ink.
1.4. Precautions
The inspection should be conducted twice in parallel, and the difference between the measured value and the average of the two measurements should be less than 5%. The average of the two test results is the viscosity of the ink sample.
The measurement range of the viscometer should match the viscosity range of the ink to be tested.
2、 Chaen cup viscometer method2.1. Principle
The Chaen cup viscometer method also characterizes the viscosity of an ink sample by measuring the time it takes for the sample to flow out of a specified diameter hole at a certain temperature. However, there are multiple models of Chaen cup viscometers suitable for measuring inks of different viscosities.
2.2. Tools and materials
Chaen cup viscometer (choose the appropriate model)
Mercury thermometer (temperature range 0-50 ℃, division value 0.1 ℃)
Stopwatch
Glass rod (used for stirring ink)
Cotton yarn
Cleaning solvent
2.3. Inspection steps
Wipe the inside of the viscosity meter cup and the leakage nozzle clean, hold the viscosity cup horizontally, and block the leakage hole with your fingers.
Pour the ink that has been stirred evenly and adjusted to (25 ± 0.2) ℃ into the viscosity cup until it is flush with the edge of the viscosity cup. Use a glass rod to scrape off the bubbles and reset the stopwatch to zero.
Release your fingers and start the stopwatch at the same time. Stop timing when the ink flow is interrupted and the first drop appears. The time indicated by the stopwatch at this time is the viscosity of the ink.
2.4. Precautions
It is also necessary to perform multiple parallel measurements and take the average to improve accuracy.
The selection of a viscometer should be determined based on the viscosity range of the ink being tested.
3、 Rotational viscometer method3.1. Principle
The rotational viscometer method characterizes the viscosity of a substance by measuring the frictional force generated between molecules when the liquid layer undergoes displacement under external force. This method is suitable for situations that require more accurate viscosity measurement.
3.2. Tools and materials
Rotational viscometer
Constant temperature water bath
Cotton yarn
Cleaning solvent
3.3. Inspection steps
Before measurement, check whether the liquid pool of the instrument is clean and calibrate the zero point.
Select the corresponding viscosity rotary hammer according to the viscosity of the sample, and place the rotary hammer into the liquid pool.
Slowly inject the sample into the liquid pool until the liquid level reaches the specified position.
Turn on the constant temperature water bath to maintain a temperature of (25 ± 0.5) ℃.
Turn on the instrument switch and record the data after the reading pointer stabilizes.
3.4. Precautions
The measurement range and accuracy of the rotational viscometer should match the viscosity requirements of the ink being measured.
During the measurement process, it is necessary to maintain a constant temperature and humidity environment to ensure the accuracy of the measurement results.
4、 Other precautionsDuring the measurement process, it is necessary to avoid the influence of vibration and other external interference factors on the measurement results.
Before measurement, the viscometer should be thoroughly cleaned and calibrated to ensure measurement accuracy.
During the measurement process, attention should be paid to safe operation to avoid accidents such as ink splashing or burns.
In summary, the viscosity measurement of water-based inks can be carried out using various methods such as the Tu-4 cup viscometer method, the Chaen cup viscometer method, or the rotational viscometer method. The specific choice of method should be comprehensively considered based on factors such as the viscosity range of the ink to be tested, measurement accuracy requirements, and experimental conditions.
RU
EN
CN
