ISO 7784-3:2000 pdf download
ISO 7784-3:2000 pdf download.Paints and varnishes -Determinationof resistance to abrasion — Part 3: Reciprocating test panel method.
Either the resulting loss in mass of the test panel is measured after a specified number of double strokes, and the loss in mass for one double stroke (mg/DS) and the abrasion resistance (DS/mg) are calculated, and/or the mean number of double strokes required for wearthrough of the coating (or the topcoat of a multicoat system) is determined (see clause 9).
4 Required supplementary information
For any particular application, the test method specified in this part of ISO 7784 needs to be completed by supplementary information. The items of supplementary information are given in annex A.
5 Apparatus and materials
5.1 Abrasion tester (see Figure 1)2)
The tester shall consist of a clamping device or pressure plate for holding the test specimen level and rigid and a
(50 ± 0,05) mm diameter wheel, to the outer circumference of which a 12-mm-wide strip of silicon carbide paper is
attached. The force between the wheel and the test surface shall be capable of being varied from zero to at least
(6,9 ± 0,05) N.3)
The abrasive action shall be produced by rubbing a test panel in a reciprocating manner (stroke length 30 mm) against a stationary wheel. Other types of instrument in which the panel and the wheel are moved relative to one another in a reciprocating manner may also be used, providing they give the same results.
After each double stroke, the wheel shall be advanced through a small angle to bring a fresh area of the silicon carbide paper into contact with the test surface before making the next double stroke.
The angle of rotation shall be such that, after 400 double strokes, the wheel will have made one complete revolution. On completion of this cycle, the strip of silicon carbide paper shall be replaced.
The frequency of motion of the test panel shall be (40 ± 2) DS/min.
The number of double strokes may be registered by means of a counter, and provision is normally made for the apparatus to switch off automatically after a preset number of double strokes has been reached (400 DS maximum). The test surface shall be kept free of loose powder or abrasion debris during the test.
5.2 Abrasive paper
The recommended abrasive paper is P180 grade silicon carbide paper (maximum grit size 150 pm). The strip shall be 12 mm wide. Its length shall be such that it covers the abrasive wheel without any overlap or gap at the ends (a strip length of 157 mm should be sufficient). It shall be attached to the wheel by double-sided adhesive tape (5.3) or self-adhesive abrasive paper shall be used (see note 3).
NOTE 1 Other types of abrasive paper may be used by agreement between the interested parties.
NOTE 2 Several grades of abrasive paper are specified in the P-series defined in the particle-size standard published by the Federation of European Producers of Abrasive Products (FEPA)4).
NOTE 3 Self-adhesive abrasive paper is also available from some manufacturers.
5.3 Double-sided adhesive tape
Ordinary commercially available 12-mm-wide tape is suitable.
5.4 Reference panel
A recommended reference panel for the calibration of abrasive paper is the PMMA panel, which is described in annex B.
Other reference panels may be used by agreement between the interested parties.
5.5 Balance
Use a balance with an accuracy of 0,1 mg.
6 Sampling
Take a representative sample of the product to be tested (or of each product in the case of a multi-coat system), as described in ISO 15528.
Examine and prepare each sample for testing, as described in ISO 1513.
7 Test panels
7.1 Substrate
The substrate shall be plane and, unless otherwise agreed, made of transparent glass, mild steel or aluminium in accordance with ISO 1514. However, paper sheeting which is suitable for the coatings under test may also be used.
