BS EN ISO 535:2014 pdf free
BS EN ISO 535:2014 pdf free.Paper and board – Determination of water absorptiveness – Cobb method
For the purposes of this International Standard, the time of test is defined as the time between the moment the water first contacts the test piece and the commencement of blotting.
Pour 100 ml±5 ml of water (5.1) or proportionately less for a smaller test area, into the cylinder, thus providing a head of 10 mm and start the timer (6.4) immediately. Use new water for each determination.
The test procedure for any selected exposure time should, where possible, conform to the conditions summarized in 10.3, the exposure time being selected according to the water absorptiveness of the paper and board under consideration. If, for example, a test time of 60 s has been selected, pour off the excess water after 45 s (see Table 1), taking care that no water comes into contact with the surface of the test piece outside the test area. Quickly unclamp the cylinder and remove it. Remove the test piece and place it, test face uppermost, on a sheet of dry blotting paper (5.2) previously placed on a flat rigid surface. 60 s after commencement of the test, place a second sheet of blotting paper on top of the test piece and remove the excess water, using the hand roller (6.2) with two rollings (once forward and once back) without exerting any pressure on the roller.
NOTE 1 On corrugated fibreboard the roller should be applied with its axis parallel to the flutes.
NOTE 2 Where corrugated fibreboard is indented by the cylinder edge or which exhibits “washboarding” it may not be possible for the blotting paper to contact the entire wet area of the test piece. In such cases it is recommended that instead of using the roller, the back of the blotting paper is gently rubbed by hand.
Immediately after blotting, fold the test piece with the wet side inside, and weigh again so that the increase in mass due to absorption of water can be determined before any loss by evaporation occurs.
NOTE 3 In the case of board it may not be possible to fold the test piece. In such cases the second weighing must be carried out with the least possible delay.
Repeat the processes described in 10.1 and above for all the other test pieces so that at least five tests have been carried out on each face of the paper or board required to be tested.BS EN ISO 535 pdf download.
