Читать книгу The Rheology Handbook - Thomas Mezger - Страница 156

Evaluation of plastisols as used in automotive industry as underseals or seam sealants. Requirement: After the application of the plastisol, the conveyor line transporting the car should not be set in motion before the structural strength of the plastisol has regenerated to 75 % of the reference value at rest. Otherwise vibrations might cause sagging or even dripping of the coatings in an uncontrollable way. Previously performed laboratory tests resulted in a viscosity reference value η(100 %) = 2000 mPas at time point t1 (see Figure 3.41).

Determination: Which period of time is required after time point t2 to reach 75 % of the reference viscosity value, thus here, η(75 %) = 1500 mPas?

M4) The percentage of regeneration within a previously defined time period

The percentage of regeneration taking place in the third interval is determined at certain time points which have been defined before the test by the user (e. g. after t = 30 and 60 s). The η-values are read off at these time points and the percentage is calculated in relation to the reference value of the first interval which counts as the 100 % value then.