The Arctic World Archive description says: "The film technology relies on silver halides on polyester. This medium has a lifespan of 500 years as measured by the ISO; simulated aging tests indicate Piql’s film will last twice as long."
Why not use a much more accessible medium like M-DISC, which claims a lifespan of at least 1,000 years? https://en.wikipedia.org/wiki/M-DISC