Banknotes are by far the largest group of security papers. Ultimately, this includes all papers for official forgery-proof documents (passports, securities, cheques, certificates, stamps). Over the course of their lives, such papers pass through many hands and, in addition to being counterfeit-proof, they must be dirt-repellent and withstand high mechanical stress (e.g. tear and kink-resistant). Our STW fibres, especially our synthetic fibres, are used for this.