Polyurethane (PU) is a versatile material with a wide range of properties, depending on the chemistry of its various types. The types of polyurethanes used in the blown film industry are thermoplastic (TPU), aromatic or alpha. Alphatics are much more expensive than others, but are generally more resistant to ultraviolet radiation and more environmentally friendly. There are also polyester or polyester based PUs that polyester based PUs have better flexibility at low temperatures and polyester based PUs are stronger and have higher chemical resistance. PUs used in blowing films have easy processability due to their high melt resistance. Their processing temperature is usually in the range of F˚400-350 (C˚ 205-180). Because these materials absorb moisture so much, if they are not completely dried before use, they can lead to gel formation, streaks, and reduced melt resistance. Blowing films made of polyurethane are generally used in special cases due to their elasticity and high strength. For example, in the viscous layer, laminate films and sailboats are used.
