(1) Purpose and Definition
A certain amount of ink (such as 0.1 ml) under a certain gravity (such as 250 grams) pressure, the diameter (in millimeters) of the ink's outward expansion (spreading), we call it fluidity.
Fluidity can be simply considered as an indicator for measuring the thinness, thickness and viscosity of ink. It has certain reference significance for controlling production and guiding application.
The measurement of fluidity is actually basically similar to the measurement principle of the parallel plate viscometer.
(2) Equipment and materials
(1) A set of fluidity Tester (two pieces of glass weighing 50 grams and 65-75 mm in diameter, one weight weighing 200 grams, and one metal fixing plate), see Figures 27-7.
Figure 27-? Schematic diagram of fluidity Tester
1. Weight; 2. Metal fixed plate; 3, 5. Round glass; 4. Ink
(2) One ink suction tube, with a volume of 0.1 ml per scale.
(3) A transparent measuring ruler (scale 60-70 mm).
(4) One constant temperature oven
(5) Minor Ink Knife.
(6) Clocks.
(3) Method
Put a set of fluidity Tester together with the ink to be tested (the ink is first dried on the glass plate) in an oven with a constant temperature of 25°C and keep it warm for 20 minutes.
Take out the ink, mix thoroughly with a small ink knife, then suck 0.1ml with an ink suction tube and put it in the center of the lower glass 5, press a piece of upper glass 3, and then press a weight 1 (start the stopwatch at the same time, or start timing ), put it in the constant temperature baking cream, take it out after 15 minutes, take off the weight, and measure the diameter of the expanded ink circle (4 in Figure 27-7) with a transparent measuring ruler.
(4) Matters needing attention
1. During the measurement process, the instrument should be placed in a horizontal state, otherwise the upper glass will tilt and slide, causing the ink to form an irregular circular shape after being pressed, which will bring difficulties to the measurement.
2 When measuring the diameter of the ink circle with a transparent measuring ruler, the eyes should be perpendicular to the scale line to avoid errors.
3. In the absence of an ink suction tube, you can also use a balance to weigh 0.1 grams of ink.
4. The determination of fluidity is better carried out in a constant temperature room.
5. The determination of ink fluidity can also be carried out with a parallel plate viscometer. The spreading diameter of the oiler in one minute is the fluidity of the ink. It is estimated that this method will be popularized in our country in the future and replace the currently used fluidity measurement method.
