Lamination (liquid adhesive) / coating
Dry laminating involves bonding two or more strips of a flexible backing material using an adhesive dissolved in a solvent (if an adhesive tape is used then the process is called complexing). These strips may be made of film, paper or aluminium foil. The adhesive is applied to the least absorbent strip which is then bonded to the second strip by the high pressure exerted by cylinders (heated if necessary), in order to produce an ultra strong lamination. This lamination may comprise two layers (duplex), three layers (triplex), or more.
Lamination techniques improve the appearance and properties of the backing materials. The type of adhesive selected is primarily dictated by the end use of the product. Various technologies can be implemented, such as laminating by calandering, flat laminating, Hotmelt® laminating,… to cover as many applications as possible.
Laminated products can be produced as log rolls or as strips wound on a reel as per the customer’s requirements. The material may be supplied by the customer or purchased by ADDEV Materials, as required.
Dry phase lamination:
- Solvent-based adhesive – Water-based adhesive
- Application of the adhesive
- Evaporation of the solvents
- Lamination of the adhesive-coated film to the second film
Coating is a surface treatment which involves applying a liquid coating (adhesive, lacquer, paint, oil, etc.) to a backing material (paper, fabric, plastic film, metal foil, etc.) to give it specific beneficial properties for a specific application.
The coating process is usually followed by drying and, if necessary, by cross-linking.
ADDEV Materials uses an engraved cylinder for its coating operations. The cylinder transfers the adhesive to the film which is then fed into a drying oven in which the solvents evaporate off.
Variables which affect the thickness of the liquid on the substrate:
- Feed speed of the substrate
- Viscosity of the liquid
- Density of the liquid
- Angle between the substrate and the surface of the bath
- Surface tension