SWITZERLAND • Generally, the printing industry is dealing with the common problem of poor metal adhesion due to de-lamination. Traditional metallization, even with plasma treatment, can result in poor metal to polymer substrate bonding. This produces de-lamination which leads to packaging failure and results in product rejects and loss of reputation.
Part of the problem is low surface energy on the metal side which also contributes to poor lamination bonding. There is increasing demand in the industry for higher levels of metal adhesion on metallized film due to the need for more complex packaging structures that requires a lamination peel strength suitable for functional needs.
Bobst claims the company’s new AluBond eliminates the need for chemically treated films. By developing a new approach through its vacuum metallizers, it is eliminating the need for chemically treated films.
High bonding strength can be achieved on almost any substrate with the AluBond, says the company. This is an advanced metal adhesion technology where metal adhesion values can be achieved of up to 5N/15mm.
The AluBond process is an in-line hybrid coating technology which promotes chemical anchoring (chelation) of the first aluminium particles creating a metallizing seeding layer that provides superior bond strength properties.
Very high adhesion is achieved when there are direct chemical bonds between the aluminium coating and the polymer surface. Increased chemical bonding by the creation of the seeding layer increases lamination bond strength and leads to high performance during lamination, extrusion and coating processes hence preventing failure of the packaging.
The AluBond, in tests, has also been shown to significantly increase dyne level retention which translates in improved ink wettability during printing and enhances structure stability during lamination.
Bobst is one of the world’s largest suppliers of equipment and services to packaging and label manufacturers in the folding carton, corrugated board and flexible materials industries.