tesa heat activated films (HAF) are based on a nitrile rubber and phenolic resin. They differ from normal adhesive tapes in that the adhesive characteristics are activated by both heat as well as pressure instead of just pressure: they are also not tacky at room temperature.
They offer a very high bond strength (>12N/mm² at 25°C) - nearly 5 times that of tesa 4965 for example (what would be considered a high performance double sided tape), very wide service temperature range from as low as -50°C to as high as 500°C, and excellent resistance to chemicals and solvents.
tesa HAF products are used in many industries and are compatible with many products – and very often with those that conventional adhesive tapes are not.
Typical applications include splicing of roofing and waterproof membranes which are coated with liquid bitumen, fibreglass mats which have low dimensional stability requiring strong splices, and aluminium rolls where resistance to very high temperatures and tensile stresses as well as various solvents is essential.
They are also now widely used in the consumer electronics industry due to their ageing and shock resistance, particularly for embedding chips into smartcards.