BS ISO 21194 pdf free download
BS ISO 21194-2019 pdf free download.Elastic adhesives – Testing of adhesively bonded joints – Bead peel test.
This document specifies a method for evaluating the adhesion of elastic adhesives and sealants [with a minimum elongation at break of 100 % and a modulus of elasticity of maximum 10 MPa 1) ] on various substrates. In this way, the effect of various coatings or the surface pre-treatments of the substrate materials on the adhesion can be compared. It can also be used to evaluate the influence of pre- treatment, substrate and adhesive on the long-term durability of adhesively bonded joints and seals. This test can also be used for process monitoring and quality assurance accompanying production.
2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 10365, Adhesives — Designation of main failure patterns
3 Terms and definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
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;
— Grade 5: less than 5 % cohesion failure ratio.
Other failure patterns than adhesion failure (AF) and cohesion failure (CF) can also occur, especially in the case of multilayer substrates. If an evaluation according to the abovementioned grading is not possible due to the failure patterns, it is not necessary to indicate a grading, but the failure patterns shall be indicated in the evaluation using the following code letters:
— adhesive not cured (NC);
— bubbles in the bulk of the adhesive (BFB);
— bubbles in the adhesion zone (BS);
— foam structure in the adhesion zone (FS);
— cohesion failure in the primer (CPrF);
— adhesion failure between primer and its substrate (SCPrF);
— cohesion failure in the paint (CFPa);
— failure between various paint layers (PaIF);
— adhesion failure between paint and its substrate (PaDF);
— corrosion of the base material (Cor);
— substrate failure in the base material (SF);
— bead tear-off without prior peeling (BF).BS ISO 21194 pdf download.
