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ERICHSEN Washability and Scrubbing Resistance Tester
Model 494
Purpose and Application
The Washability and Scrubbing Resistance Tester, Model 494, is mainly intended to assess
the ability of paints (especially plastic dispersion types) to be cleaned, washed and scrubbed.
Principle of Test
a) in accordance with DIN 53 778, Sheet 2*) The dispersion paint is applied to a foil, dried and -
if specified - contaminated in a defined manner, after which it is scrubbed under wet conditions
(using a micro-dosing pump) by the to and fro motions of the brush. The „cleanability“ and the
washing and scrubbing resistance are assessed in the same process by examining the specimen after a predetermined number of scrubbing cycles to check whether the contamination has been
removed or the coating is scrubbed through to the substrate.
b) in accordance with ASTM D 2486 The test paint is applied to a black plastic foil, dried and placed on a glass plate. An 0.25 mm high and 12.7 mm wide sheet metal strip is then placed
between the foil and the glass plate and the specimen is fixed using a sealing frame after which
it is scrubbed using a nylon brush and washing fluid until damage (a continuous line) can be seen in the area where the sheet metal strip has been inserted.
c) in accordance with DIN EN ISO 11998 The dispersion paint is applied to a plastic foil, dried
and soiled. The abrasive pad is saturated with 4 g of washing liquid and then pulled over the testing surface (200 cycles to-and-fro), the abrasive pad holder guaranteeing a defined load
(135 g). The cleanability is determined by visual comparison of the scrubbed area with the adjacent unscrubbed areas. The wet scrub resistance is derived from the loss in mass caused by the scrubbing process.
*) withdrawn; replaced by DIN EN ISO 11998.
Design and Operation of Apparatus
The instrument (with levelling feet) is equipped with a cover plate on which the steel trough with an
integrated specimen clamping device is placed. The linear to and fro motion is obtained from an electric
motor and transmitted via an eccentric and cable arrangement. A presetting counter registers the
cycles (= to and fro motions).
Weight, nett : approx. 15 kg
Electrical connection : 230 VAC
(optional 115 VAC)
Actual length of motion : (300 ± 5) mm
Cycle frequency :(37 ± 1) cycles to-and-fro/min
The scope of supply includes:
Washability and Scrubbing
Resistance Tester, Model 494
♦ steel trough with outflow connection
♦ glass plate
♦ box level
♦ spare pull cable
♦ operating instructions
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