| abstract |
The present application discloses a thermally expandable composition comprising 20-85wt% of at least one thermoplastic polymer P that can be cross-linked by free radical reaction, 2-15wt% of at least one azo radical initiator I , optionally up to 25 wt% of at least one adhesion promoter AD, up to 10 wt% of at least one tackifier T, up to 2.5 wt% of at least one antioxidant AO, and up to 2.5 wt% of at least one A polyacrylate AC having a molecular weight of less than 2500 g/mol, wherein each amount is based on the total composition before swelling. The thermally expandable composition is free of commonly used blowing agents such as azodicarbonamide, but exhibits excellent performance in terms of expansion stability over a wide temperature range of 120°C to 200°C, and is particularly suitable for barrier and /or reinforcement elements, such as in the automotive industry. |