BS ISO 22970:2019 pdf free.Paints and varnishes – Test method for evaluation of adhesion of elastic adhesives on coatings by peel test, peel strength test and tensile lap- shear strength test with additional stress by condensation test or cataplasm storage.
It describes the adhesive strength testing of adhesives on coatings by determination of the tensile lapshear strength. This method yields both qualitative and quantitative results. It is suitable for testing complete bonded assemblies as later used in practice. This also includes the use of original adherends. The tensile lap-shear strength of overlap specimens is determined by stressing in shear of an overlap joint between rigid adherends by applying to the adherends a tensile force which is parallel to the bond area and to the major axis of the specimen. The reported result is the maximum force or maximum tensile shear stress measured for each bond width.After complete curing of the adhesive, testing is conducted according to adhesive strength test method A, B or C, either immediately or following subsequent climatic exposure (exposure method 1 or 2).The response time of the testing machine shall be sufficiently short to prevent influences on the accuracy when measuring the force at failure. The recorded force shall not deviate from the actually required force by more than 1 %. The testing machine shall be capable of applying the required tensile force increasing at a steady rate. It shall be provided with a pair of suitable self-aligning grips to hold the specimen. The grips and attachments shall be constructed such as to move into alignment with the specimen as soon as the force is applied, so that the longitudinal axis of the specimen will coincide with the direction of the required force through the centre line of the grip assembly to avoid bending moment. Grips that operate by bolting through the adherends shall not be used since tearing of the bolting holes is to be expected. BS ISO 22970 pdf download.