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How to inspect the viscosity of HPMC? High Viscosity or Low Viscosity?
HPMC - Inspection viscosity
If the marked viscosity is less than 600mPa • s, check according to method 1 ® 80%~120% of the marked viscosity; If the marked viscosity is greater than or equal to 600mPa * s, the viscosity shall be 75%~140% of the marked viscosity according to method 2.
Take an appropriate amount of this product (calculated as dry product), add 90X: water to make a solution of 2.0% C g/g), and fully stir it for about 10 minutes until the particles are completely evenly dispersed and wetted and there are no undissolved sample particles on the inner wall of the bottle. Cool it in an ice bath, and continue to stir it evenly during the cooling process to remove bubbles. If necessary, adjust the weight with cold water to remove all foam as the test solution.
Method 1: at 20 t ± 0 L C, according to the outflow time of not less than 200 seconds, select the Ubbelohde viscometer with suitable inner diameter to measure the kinematic viscosity (v) of the solution, and measure the density (P) of the solution under the same conditions.
Method 2: at 20t ± 0 R c, select a suitable single-column rotary viscometer (Brookfield type LV model or equivalent viscometer) to measure the conditions in the following table (general rule 0633 third method), rotate for 2 minutes, stop for 2 minutes, repeat the experiment for 2 times, and take the average value of the three experiments.
The buyer need check the viscosity after receive hpmc goods in warehouse.