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With v = 0.2 m/s (or 5 s per m), and h = 100 µm = 0.1 mm = 10-4 m; result: γ ̇ = 2000 s-1

1d) Blade-coating of adhesive dispersions (e. g. for pressure-sensitive adhesives PSA):

With the application rate AR (i. e. mass per coating area) m/A [g/m2]; for the coating volume V [m3] applies, with the mass m [kg] and the density ρ [1 g/cm3 = 1000 kg/m3]: V = m/ρ

Calculation: h = V/A = (m/ρ)/A = (m/A)/ρ = AR/ρ; with AR = 1 g/m2 = 10-3 kg/m2 holds:

h =10-6 m = 1 µm; and then: γ ̇ = v/h. See Table 2.2 for shear rates occurring in various kinds of blade-coating processes [2.4] [2.5].

Table 2.2: Shear rates of various kinds of blade-coating processes for adhesive emulsions
Coating process	Application rateAR [g/m2]	Coating velocityv [m/min]	Coating velocityv [m/s]	Layer thicknessh [µm]	Approx. shear rate range γ ̇ [s-1]
metering blade	2 to 50	up to 250	up to 4.2	2 to 50	80,000 to 2 mio.
roller blade	15 to 100	up to 100	up to 1.7	15 to 100	10,000 to 100,000
lip-type blade	20 to 100	20 to 50	0.33 to 0.83	20 to 100	3000 to 50,000
present maximum	2 to 100	700	12	2 to 100	120,000 to 6 mio.
future plans		up to 1500	up to 25		250,000 to 12.5 mio.