1. Scope and description
This method is applicable to products with Newtonian or nearly Newtonian plastic fluid coatings, and is limited to the determination of test materials that can accurately determine the breakpoint of the flow of liquid flowing out of the outflow hole of the outFlow Cup.
This method specifies four kinds of outFlow Cups with similar sizes and outflow apertures of 3mm, 4mm, 5mm and 6mm respectively. The outflow time of the tested sample should not exceed 100s, otherwise, due to the delay effect, the cut-off point will be difficult to judge, and repeated Difference.
2. Instruments and Materials
(1) The ISO cup is also called the ISO outFlow Cup. It is a container with a cylindrical upper part and a conical lower part. subject to accidental damage.
(2) The thermometer is accurate to 0.2°C, and the graduation interval is 0.2°C or finer.
(3) Bracket It is used to support the outFlow Cup and is equipped with screws for adjusting the level.
(4) The stopwatch is divided into 0.2s.
(5) Flat glass plate or straight-edged scraper.
(6) To withstand the cup.
3. Measurement method
(1) Preliminary test
①After fully stirring the sample, pour it into an outFlow Cup of a selected label. Release your hand within 5 seconds of filling the outFlow Cup, and measure the outflow time with a stopwatch.
② Repeat the measurement, keep the sample in the outFlow Cup for 60s and then release your finger.
③ If the difference between the two results is greater than 10% of their average value, the sample is non-Newtonian, so it is not suitable to use this method for viscosity determination.
(2) Determination of outflow time
① Select an outFlow Cup with a certain aperture, so that the outflow time of the sample in the outFlow Cup is preferably between 30 and 100s.
②Adjust the temperature of the sample and the outFlow Cup to (23±0.5)°C or other agreed temperature.
③Put the outFlow Cup on the bracket, and adjust the horizontal screw on the bracket to ensure that the outFlow Cup is in a horizontal position.
④Block the hole of the outFlow Cup with one finger, and slowly pour the sample into the outFlow Cup to avoid air bubbles. Use a glass plate or scraper to scrape flat along the upper edge of the outFlow Cup to scrape off excess sample or air bubbles.
⑤ Place the receiving cup under the outFlow Cup, and the distance from the outflow hole should not be less than 100mm. Quickly remove your finger and start the stopwatch at the same time. Stop timing immediately when the flow of the outflow hole is interrupted for the first time, and the time displayed by the stopwatch is the outflow time, accurate to 0.5s.
4. Result representation
The average value of two measurements is the measurement result. The difference between the two measured values should not be greater than 5% of the average value
5. Reference standard
National standard GB/T 6753.4 "Paints and varnishes - Determination of outflow time with outFlow Cup".
International Standard ISO 2431 "Paints and varnishes - Determination of outflow time by outFlow Cup (fourth edition)".
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