Polyester film boasts good toughness, mechanical strength and excellent transparency, yet it has poor slipperiness. Adding slipping agents will cause slight hazing of the film, so no other additives are required. Polyester film is inert to food products.
Heat sealing of polyester film is quite difficult, as the film tends to shrink and become brittle due to crystallization. Therefore, polyester film is usually sealed with adhesives, while the optimal method is to laminate it with polyethylene to take advantage of polyethylene film’s excellent heat-sealing property.
Polyester film features a fairly low water vapor transmission rate, which is comparable to that of polyethylene. It also has low permeability to air and odors, a characteristic similar to nylon. It is resistant to dilute acids and alkalis, but concentrated acids and alkalis can react with it. Moreover, it is resistant to most solvents, oils and fats.
Polyester film has excellent tear resistance, folding endurance and wear resistance, along with good impact resistance that can be maintained down to approximately -70℃. It also exhibits outstanding electrical insulation, with quite high dielectric strength, dielectric properties and volume resistivity.
Unstretched and unoriented polyester film can be thermoformed. Stretched and oriented polyester film without heat setting can be used as shrink film, with a shrinkage temperature of around 100℃.
Polyester film can be vacuum metallized, and the metallized film has excellent decorative properties. Polyester film is widely used in packaging, industrial and agricultural fields, among which the major application areas include magnetic tape substrates, photographic film bases and electrical insulation materials.
