ISO 2812-3:2019 pdf free.Paints and varnishes – Method using an absorbent medium.
5 Apparatus and materials Ordinary laboratory equipment and the following.
5.1 Air oven, with artificial ventilation, for carrying out the test at temperatures up to 40 °C and capable of maintaining the temperature to within ± 3 °C.
5.2 Watch glasses, with a diameter of approximately 40 mm, curved in such a way that, when placed over a test area (see 9), the watch glass will not touch the filter paper or cotton wool swab, impregnated with the test liquid, on the test area.
5.3 Petri dishes, with 60 mm diameter and 20 mm rim.
5.4 Filter paper, of a type that will not be affected by the test substance used, with a diameter ot approximately 25 mm or 36 mm.
NOTE 1 So-called depth filter sheets (e.g. those used for polishing automotive paint coatings in laboratory testing) have been found suitable for this test. These sheets consist of a cellulose matrix containing a mixture of very fine kieselguhr and perlite particles as the filtration-active substances.
NOTE 2 For most purposes, laboratory filter paper with a thickness of 1,0 mm to 1,25 mm will be suitable.
5.5 Cotton wool, lint-free and of a type that will not be affected by the test substance used. Cotton wool may be used instead of filter paper (SA) for the test and for cleaning the test panel at the end of the test period (see Clause 10).
6 Test substances
One or more test substances, as agreed between interested parties, shall be used. Examples of test
substances are given in Annex A.
7 Sampling
Take a representative sample of the coating material to be tested, as described in ISO 15528.
Examine and prepare the sample for testing, as described in ISO 1513.
8 Test panels
8.1 Substrate
Unless otherwise agreed, use test panels conforming to the requirements of ISO 1514, with dimensions of approximately 150 mm x 100 mm and a thickness of 0,7 mm to 1,0 mm.
8.2 Preparation and coating
Prepare each test panel as described in ISO 1514 and then coat it by the agreed method with the product or system under test. Dry (or stove) and age (if applicable) each coated test panel for the specified time under the specified conditions.
8.3 Coating thickness
Determine the dry-film thickness of the coating, in micrometres, using one of the non-destructive methods given in ISO 2808.
9 Procedure
9.1 Conditioning of the test panels
Immediately before testing, condition the test panels for at least 16 h under standard conditions as specified in ISO 3270, i.e. (23 ± 2) °C and (50 ± 5) % relative humidity.
9.2 Test conditions
Unless otherwise specified, carry out the test at the standard temperature specified in ISO 3270, i.e.
(23 ± 2) °C.
9.3 Determination
Perform the test in duplicate.
Place the test panel horizontally. When using liquid test substances, dip a filter paper or cotton wool swab into one of the test liquids and wait until the filter paper or cotton wool is thoroughly impregnated with the liquid. Take the filter paper or cotton wool swab out of the liquid and let excess liquid run off. Do not compress the filter paper or cotton wool to remove excess liquid. Place the filter paper or cotton wool swab on the test panel.
Repeat this procedure for each test liquid, making sure that the filter papers or cotton wool swabs do not touch one another and that the distance between the filter papers or cotton wool swabs and the edges of the panel is at least 10 mm. Then immediately cover the test areas with watch glasses or Petri dishes.
When using highly viscous or paste-like test substances, apply about 0,5 cm3 of each substance to the test panel, place a filter paper or cotton wool swab over the substance and cover the test areas with Petri dishes.
The test duration shall be agreed between the interested parties and should reflect the end use of the coating.ISO 2812-3 pdf download.