FINAT Test Method 2 Peel Adhesion 90°

FINAT Test Method No. 2 (FTM 2) is used to investigate peel adhesion of laminates through an angle of 90° with a test speed of 300 mm per minute. Predominately used with laminates and packaging materials, it can also be used for coated laminates to investigate adhesion strengths.

In principle, the test specimen is supported by using a test plate and attaching the test sample by removing the backing material from each strip and placing the adhesive coated facing material adhesive side down onto a clean test plate using light finger pressure. The specimen is rolled twice in each direction with the standard FINAT test roller to ensure proper contact.  The adherend is pulled from the substrate to measure the peel strength, generally presented in an average load divided by the specimen width.

The challenges of testing to this standard are:

• Maintaining a 90° angle throughout the test
• Data rate used to capture peaks and troughs
• Eliminating slippage throughout the test

Instron Solution:

• Maintaining a 90° angle throughout the test – The 90° peel fixture is able to maintain this angle by using a low force sliding table that is adjusted throughout the test.  The fixture consists of a bearing mounted table, which is linked to the test system via a cable and pulley, as well as anchored on the back by a dampening coil spring. As the crosshead is driven in the tensile direction, the cable pulls the table to maintain a constant 90° angle peel, and the coil spring keeps the table from reacting to inertia caused by load peaks and troughs. This fixture is adaptable for both single and dual column frames.  
• Data rate used to capture peaks and troughs – Instron’s 5900 series frames enables data capture of up to 2.5 kHz to ensure that all fast changing test events are captured.  Too low of a bandwith may “dull” the system and lead to missed peaks and troughs, resulting in lower average strength values. 
• Eliminating slippage throughout the test – Pneumatic grips are a great choice for peel testing as they are able to maintain constant gripping pressure throughout the testing.   The grips employ a patented “quick-change” jaw face design which enables operators to easily change jaw faces to accommodate the needs of their materials.