Everyone hopes to protect our beautiful earth, and to protect our environment with environmentally friendly things.Designers and researchers have been looking for renewable resources that can be reused in some way, easily recycled, or compostable and/or biodegradable materials. Much effort has also been focused on reducing the total amount of packaging by reducing measurements and eliminating layers and environmentally unfavorable materials.
While these efforts are beneficial, a often overlooked opportunity for the sustainability of flexible packaging is the manufacturing process itself. To make flexible packaging in the most sustainable manner possible, solventless adhesive lamination techniques, also known as solventless lamination, can be used.
The laminating adhesive used in this method is a two-component polyurethane. The two components must be mixed together in a suitable manner to form a useful adhesive that bonds the layers of material to each other to form a flexible packaging substrate. The manufacturer of these binder components controls the viscosity properties of the final product such that no solvent is required to maintain the material as a liquid; therefore, there is no solvent.
Solvent-free lamination technology uses a computer-controlled meter, mixing, dispensing unit (MMDU) to continuously measure the exact amount of each component, and then mixes and dispenses a small amount of solvent-free binder into the laminating equipment. This is in contrast to conventional lamination methods in which large quantities of up to 55 gallons of adhesive are pre-mixed for use in the manufacturing process; this can result in excessive waste.
The laminator applies an adhesive and combines the two layers of material to form a flexible package laminate. Since no solvent is discharged from the adhesive, an overhead oven is not required to dry the adhesive. The two materials are combined, wound into a roll, and the adhesive is crosslinked or cured for a specified period of time and then transferred to the next stage of manufacture.
There Are Three Very Important Reasons:
1. A lot of waste. Only the amount of binder required for lamination is mixed and dispensed. Since the binder is continuously mixed, there is no extra waste. When the laminating device is stopped, the adhesive mixing is thus stopped, thereby greatly reducing the waste of the adhesive.
2. Energy saving and environmental protection. Since no solvent needs to be discharged from the adhesive, there is no need for an overhead drying oven. The result is that natural gas saves a lot of energy. Additional energy savings include reduced power usage because large blower motors are not required to circulate hot air within the drying oven. The solvent-containing air does not need to pass through a secondary thermal oxidation process to destroy the solvent before it is released to the atmosphere, so that natural gas can be further saved.
3. Reduce materials. Solventless adhesives tend to use lower coating weights than other adhesive lamination techniques, again resulting in less pounds of material for the same amount of packaging.
Solvent-free adhesive lamination is a sustainable manufacturing method because it reduces waste, reduces material usage and saves a lot of energy. A significant reduction in energy use can be directly associated with a significant reduction in the release of carbon compounds into the atmosphere.
