Tpu film has been widely used in the packaging field. Tpu film can be used for food packaging, electrical product packaging, daily necessities packaging, clothing packaging and so on. They need to print the color of the tpu film, and as a food package, they also need to perform multi-layer composite or vacuum aluminum plating.
Tpu films have different requirements in different applications. The tpu film manufacturer tpu film has high surface free energy and large wet tension to facilitate the strong adhesion of printing ink, adhesive or aluminized layer to tpu film; when used in electrical appliances, electronic products, etc. The film is required to have certain antistatic properties and the like. In the tpu film production coiling and high-speed packaging process, the film surface is required to have a certain frictional property to prevent the film from sticking or slipping.
The tpu film manufacturer tells you that the surface tension of the tpu film depends on the free energy of the surface of the tpu film, which in turn depends on the molecular structure of the film material itself. Most tpu films such as polyolefin films (LDPE, HDPE, LLDPE, PP) are non-polar polymers with low surface free energy and low surface wet tension, typically around 30 dynes/cm. In theory, if the surface tension of the object is less than 33 dynes/cm, ordinary inks or adhesives cannot adhere firmly, so the surface must be treated.
Polyester (PET, PBT, PEN, PETG) is a polar polymer with a high surface free energy and a surface wet tension of 40 dynes/cm or more.