At first, PET was developed for use by two chemists named Rex Whinfield and James Dicksonin 1941. They were working for a small British company by the name of Calico Printer's Association in Manchester. At the time it was used for manufacturing synthetic fibers in the postwar era under names such as "polyester", "Dacron", and "terylene". The patent rights were sold to Du point and ICI who sold regional rights to many other companies. Although the original intention for PET was for producing synthetic fibers, other uses were soon discovered. By the mid 1960's it was being used to package films, and in the early 1970's methods for blowing bi-axially oriented bottles was in commercial development. Bottles now represent the most significant use of PET moulding resins.