Currently in the metal packaging industry for aluminum resist processing method is mainly applied to the surface of aluminum organic polymer coating --- paint. This method is the only way for many years the vast majority of enterprises to adopt almost become. Toyo Seikan Japan in recent years has developed and successfully applied to a metal plate coated two-piece beverage cans production. Undoubtedly metal plate coating technology is a process of environmental protection, more reliable performance, low-cost new metal plate resist processing technology.
1 aluminum cover film method
Aluminum coating, by definition is at the surface of the aluminum plate covered with a layer of polymer plastic film.
In the metal plate including aluminum surface of the composite layer of polymer film technology is also nothing groundbreaking technology, this technology as early as in the electronic materials are widely adopted. One of two ways.
(1) with adhesive composite technology
There is a composite adhesive film technology or in one or both sides of a metal plate coated with a layer of adhesive, removing the solvent by heating and baking the composite pressure composite, the composite product even after some heat-treated to get a qualified The product. The aluminum coating can also be used similar methods have adhesive composite film.
(2) adhesive-free composite technology
No adhesive composite technology is the use of a polymer film is heated to a viscous and viscoelastic state is generated composite metal plate. No adhesive composite key technology is to obtain a functional polymer film. Currently available industrial polymer film after heating aluminum composite bonding force is small, it can not be used directly. Can the company Toyo polymer film used was a modified PET film (polyester film).
Hydrolysis issue ordinary polyester film is used extensively for beverage packaging, but its long-term exposure to acid have been cause for concern, tests showed normal polyester film directly after the aluminum compound, the aluminum surface due to the presence of alumina (alumina catalyzes the reaction of polyester) such that the polyester film is rapidly degraded in boiling, performance abruptly deteriorated. So ordinary polyester film can not be directly used to prepare the composite and aluminum beverage packaging material coated with aluminum.