The Washability and Scrubbing Resistance Tester, Model 494 MC (attached with leveling feet) has a top cover plate on which the steel trough for the testing performance is placed. Further, it is equipped with two specimen clamping devices. A high-precision step motor operated by a micro-controller allows a periodic linear movement of the drive frame which holds/guides the abrasion bodies, with a high repeatability. The swivel-mounted frame for inserting the abrasion bodies is designed for holding/guiding up to three of them. Due to this up to three parallel abrasion tests are possible.

For tests according with DIN EN ISO 11998, the supplied ISO adapter has to be mounted. The operation via keypad and 6-line-display is comfortable, with the functions:

• controlling the stroke (start, stop, reset)
• setting the test parameter (stroke rate, stroke path, number of double strokes)
• storage of frequently used test sequences(up to 20 sets of parameters).

Purpose and Application: The ERICHSEN Washability and Scrubbing Resistance Tester, Model 494 MC, is mainly intended for the determination of the washing and scrubbing resistance as well as cleanability of dispersion paints (specifically "wall paints"). The wide range of its adjustable parameters allows also some further tailored/customized testing matters (for example for testing cleaning agents/solutions, etc.) as well.

Principle of Test: In the standard applications a matt black PVC foil will be coated, and - if required - soiled in a defined manner. After clamping into the device it will be exposed under the influence of a washing liquid the stress of the moving scrub body.

There are a few main standards of testing that can be applied:

DIN 53 778-2* (*withdrawn, replaced by DIN EN ISO 11998) The scrub body is a defined pig bristle brush, which is charged with 250 gm weight. The washing fluid is continuously fed by a micro dosing pump. Whether the contamination has been removed or the coating is scrubbed through to the substrate, will be checked after an agreed number of scrubbing cycles.

ASTM D 2486 The scrub body is a defined nylon brush, which is charged with 454 gm weight. The washing liquid is applied manually during the test at regular intervals and in a defined amount. For sharpening the wear effect of the scrubbing action, a narrow thin strip of metal sheet will be placed centrally and transversely to the stroke direction under the foil. The test result is the number of double strokes up to scrubbed through to the substrate.

DIN EN ISO 11998 The scrubbing body is a defined type of abrasive pad **) loaded with 135 gm weight, which is moistened prior to the test only once with a defined quantity of the washing fluid. After scrubbing strain (200 double strokes) the mass loss per unit area of the coating and the average layer thickness loss will be determined. **) Abrasive pad "3M Scotch Brite, No. 7448" can be obtained from the dealer.

The tester is equipped with levelling feet and a cover plate on a steel trough with an integrated specimen clamping device.  Powered by an electric motor a pre-set counter measures the cycles. 

Technical Data
Dimensions: (WxDxH) 590 x 370 x 280 mm
Weight: (net) approx. 22 kg
Power supply: 240V AC
Stroke rate: (5 - 70) double strokes/min
Stroke path: (10 - 300) mm, depending on the stroke rate