PSTC 16_{Loop tack}

Test summary

The tack force is that required to separate the adhesive from the adherend shortly after they have been brought into contact with just the weight of the tape itself on a 24 x 24 mm contact area.

Test apparatus

Tensile tester with grips and suitable range loadcell.

Test plates 24 x 24 mm made of specified stainless steel.

Cutting apparatus.

Cleaning materials and solvents as detailed in the standard.

Preparation

Cut strips from a representative sample 24 mm wide and 175 mm long in the machine direction.

Condition the specimens at 23 ±2 °C and 50 ± 5%. RH for at least 24 hours.

Clean the stainless steel plate as detailed in the standard using the materials and solvents specified.

Test method

Representative samples of the material are cut to 24 mm width and formed into a loop with the adhesive facing outwards. The loop is lowered at 300 mm per minute onto a 24 x 24 mm stainless steel plate, then immediately pulled off while the maximum force is recorded. The average of the peak force of at least replicates is calculated, and reported as peak load per 10 mm width of sample.

The test strips should be conditioned at 23 ±2 °C and 50 ± 5%. RH for at least 24 hours.

Clean the stainless steel plate with the solvents and protocol detailed in the standard.

Clamp the stainless steel plate in the lower (fixed) grip of the tensile tester.

Form the sample into a loop with the adhesive on the outside. Clamp the ends of the loop into the upper (moving) grip of the tensile tester.

Set the tensile tester to descend at 300 mm per minute and bring the loop into contact with the stainless steel plate..

When full contact over the stainless steel plate has been achieved (24 mm x 24 mm), immediately reverse the direction of the tensile tester and pull upwards at 300 mm per minute until the loop is completely detached.

Record the maximum force necessary to completely separate the loop from the stainless steel plate.

Repeat for at least three replicates.

Report

Record the maximum force required to remove the specimen loop from the stainless steel plate as well as the mode of failure. Calculate the average peak reading in newtons/10 mm using at least three replicates.