Generally speaking, there is no difference between PU film and TPU film with a thickness of 0.03mm or thicker. Many people, especially in shoe factories and printing plants, habitually refer to both thick and thin TPU films as PU film.
However, PU film with a thickness below 0.03mm is completely different from TPU film.
PU film is manufactured adopting a coating process, which is reacting with a solvent. It can be made very thin, but achieving a thickness greater than 0.025mm is very difficult.
TPU film, on the other hand, is generally made using film blowing, casting, or even calendering methods. Its thickness can range from 0.01-2.5mm, and the TPU melting and flowing traces may be visible when heated.
PU film has good flexibility and high moisture permeability, due to its thinness and solvent evaporation .
TPU film utilizes hydrophilic groups for moisture permeability; highly permeable TPU films also have very high moisture permeability.
Since PU film has a backing paper, and the backing paper has a high degree of matte finish, the PU film has a very matte and frosted appearance.
TPU film can be made with a matte finish, but achieving an extremely matte surface is still difficult.
The specific gravity of PU film is approximately 0.9.
The specific gravity of TPU film is approximately 1.2.
PU film is easy to make into colored products.
While TPU film requires a higher minimum order quantity for colored products. This is mainly because the PU only requires coating, while the TPU requires screws cleaning.
PU film is widely used in leather, clothing, and medical and hygiene fields.
While TPU film is widely used in shoe materials, bag materials, clothing, and inflatable products.
Due to the solvents used, PU film is not so environment-friendly as TPU film.
PU film is with thermosetting property and cannot be reprocessed.
TPU film is thermoplastic and can be processed multiple times.
For the same thickness, PU film is usually more expensive than TPU film.