BS ISO 21194:2019 pdf free.Elastic adhesives一Testing of adhesively bonded joints – Bead peel test.
4 Principle Adhesive beads are applied onto substrates. These are then peeled off again after curing and a possible subsequent climate resistance test. If an ageing is performed, the individual steps shall progress in succession with the test specimen, whereby a partial area is peeled off further before the ageing and after every ageing step. The failure pattern is then determined. 5 Sample preparation 5.1 Materials and surface treatment The bonded joint materials and the surface treatment shall be selected according to the requirements of the application. 5.2 Adhesive application For every test specimen, at least one adhesive bead with a length of minimum 80 mm, but with sufficient length for the number of intended ageing levels [each about 50 mm) shall be applied onto the jointing part. 8 Implementation To test the adhesive bonding, the bead shall be cut through with a sharp knife obliquely under about 45° in the direction of peel as far as the bonding surface and pulled off with pointed pliers at the same time (peeling angle 130° to 160°) or peeled off by unrolling. The peeling force shall be increased until a crack begins to progress. If the failure progresses in the adhesive, the bead shall be continuously newly incised during the peeling process. These incisions shall continue in the peak angle between the bead and jointing part surface up to the bonding surface. There should be an interval of about 3 s between each incision, during which the material is subject to further strain. This process shall be repeated until a bead piece of minimum 50 mm per ageing cycle is peeled off. 9 Evaluation The failure patterns of the peeled beads shall be appraised for the evaluation. The failure patterns shall be evaluated in accordance with ISO 10365. As the failure can also progress in the coatings or their interfaces in the case of a multilayer structure of the jointing part (paint, primer, etc.), this shall be differentiated during the evaluation. The failure patterns shall be evaluated in the following manner: – Grade 1: More than 95 % cohesion failure (CF) ratio and less than 5 % adhesive detachment [AF) of the adhesive from the contact surface; -Grade 2: 75 % to 95 % cohesion failure ratio; -Grade 3: 25 % to < 75 % cohesion failure ratio; -Grade 4:5 %to< 25 % cohesion failure ratio;BS ISO 21194 pdf download.