Mechanical process of building a laminate by bonding repeated laminations, or layers, of material onto one another. If the layers have a grain, such as in wood, they are often bonded with their grains at different angles to achieve greater strength in the finished material.
Laminating processes can be classified according to the type of bonding agent used to produce the laminates:
- In wet lamination the bonding agent is still in a liquid state when the webs are joined together. It is commonly used to produce a paper-aluminium foil laminate that is widely used in flexible packaging
- In dry lamination, the bonding agent, dissolved into a solvent, is applied on to the less porous and more heatsealable web, before being evaporated in the drying oven. Then the adhesive coated web is laminated to the other web under a strong pressure by means of heated rollers to improve the bond strength of the laminate
- In wax lamination the bonding agent, wax or hot melt, is applied in a molten state onto one of the two substrates. This process enables to produce paper-paper or paper-aluminium foil laminates that are widely used for packaging biscuits and bakery products in general
- Solventless lamination is a process where the adhesives used do not contain solvents.