CHROMATOGENY: This technology involves modifying cellulose to make it water-resistant by grafting fatty acids onto paper. Palmatic or lauric acid and kraft lignin from resinous and hard woods are esterified. The resulting esters are applied to the cardboard by a bar coater. The method is still at the R&D stage but is used to create a water-resistant barrier.
COATING: Coating is a barrier technology involves the use of a solvent or aqueous solution, or aqueous spray, followed by a drying process. It consists of applying one or several coats on the surface of a material to give it certain properties. The coating product can be in liquid, melted or vapour form.
COLAMINATION: Colamination is a process that involves assembling two substrate materials using a very liquid polymer binding layer applied by an extruder. A primer can also be applied to one of the film substrates to improve adhesion between it and the polymer binder. Similarly, a surface treatment (such as corona – surface tension modification) can be applied to one of the substrates. Cardboard (with or without printing) covered with a plastic or metal layer becomes a “laminated cardboard” material. Combining a sealing film with paper produces a sealable composite material. Applying a polymer binder in melted form avoids the use of glues or adhesives. Modified PE is an example of the type of binder used.
DEFIBRATION: This operation consists of breaking down cellulose into individual fibres mechanically (wood chips are ground between discs – refiners – whose opposing movements mechanically separate the fibres from each other) or chemically (wood chips go through chemical baths which dissolve the lignin, thereby separating the fibres).
DISPERSABLE ADHESIVES: They are broken down into small particles (<1 µm) by pulper and remain suspended in the water.
EXTRUSION COATING: An extrusion process whereby a polymer (PE, PP, PET, mixed polymer, additives, etc.) passes through a heating die to turn it into a melted polymer (extrudate). A layer of extrudate (ranging from < 10 g/m² to 20 g/m²) is applied to a paper or cardboard substrate material. The molten polymer then penetrates into the pores of the fibrous paper or cardboard material, cools down and adheres to the surface.
LAMINATED PAPER AND CARDBOARD PACKAGING: Packaging where paper and cardboard make up 50% of its weight and at least one of its paper/cardboard sides is completely covered with another material,
- which is closely bound or glued,
- OR the proportion of which is over 15% of the weight of the paper/cardboard substrate material.
LAMINATION: Multilayering via lamination is a type of solid barrier technology involving the use of solvent or aqueous solution adhesives, aqueous dispersion adhesives, or wax and hot-melt adhesives.
The lamination process consists of gluing two substrate materials together with an adhesive.
The layers to be glued to the paper can be films, thin aluminium sheets (paper-plastic composites, etc.).
Generally, an adhesive is applied to the least absorbent layer and the second layer is then pressed firmly on top to create a two-ply, or duplex, laminated material.
METALLISATION: This process generally consists of applying a metal coating (thin aluminium layer) to plastic films (PET or OPP). The film is then applied to paper using a lamination technique. This type of metallisation involves a process of physical vapour deposition (PVD) through evaporation in a vacuum. The aluminium is evaporated in a hermetically sealed vacuum chamber. The vacuum allows the particles to adhere directly to the substrate where they return to a solid state. The deposited layer is extremely thin – only 5 to 100 nanometres. This process can also be used to apply an AlOx (Aluminium Oxide) mineral barrier.
Mineral Oils: Mineral oils are a blend of chemical compounds derived from petroleum. They may be used to formulate and/or produce certain types of inks and glues used for printing, forming and sealing graphic paper and packaging. Mineral oils include two main categories of compound: MOSH (Mineral Oil Saturated Hydrocarbons) and MOAH (Mineral Oil Aromatic Hydrocarbons).
Although the properties of some of these mineral oil compounds are compatible with cosmetics and food industry applications, aromatic hydrocarbons (MOAH) are considered a concern by ANSES (the French Agency for Food, Environmental and Occupational Health & Safety) due to their effect on health. It has been established that some of these mineral oil compounds may migrate from paper and cardboard packaging to food and may end up in recycled materials produced from this packaging, questioning the use of mineral oils in this type of packaging.
MODIFIED CELLULOSE: The cellulose molecule is chemically modified in a permanent way by adding chains and/or modifying links. Cellulose acetate falls into this category. When cellulose, which is a naturally occurring polymer, has been modified like this, it is no longer considered to be “natural” and is therefore classed as a plastic according to the EU’s SUP (Single-Use Plastics) Directive.
NATURAL FIBRES (cellulose) : Cellulose fibres extracted directly from a plant via a mechanical or chemical process.
NON-LAMINATED PAPER AND CARDBOARD PACKAGING: A paper/cardboard packaging item that does not meet the criteria associated with laminated paper and cardboard packaging is classed as non-laminated paper and cardboard packaging.
PAPER AND CARDBOARD (material): A material made of natural cellulose fibres, obtained by defibrating wood or other plant-based materials, mixed with mineral fillers.
PAPER AND CARDBOARD PACKAGING: Packaging where paper and cardboard make up 50% of its weight.
Partially dispersible/non-screenable adhesives: This includes most PSAs. They are tacky and introduce particles called “stickies” into the process, resulting in quality defects in the recycled paper, as well as additional machine maintenance and water treatment costs.
PSA (Pressure Sensitive Adhesive): An adhesive which bonds when pressure is applied, without the need for solvents, water or heat to activate the adhesive.
PVOH: A water-soluble polymer used as an adhesive or barrier.
REGENERATED CELLULOSE (Viscose): The cellulose present in wood is chemically separated from all the other elements to produce a viscous solution (hence the name Viscose). After filtration, the solution is regenerated to produce the cellulose originally present. This viscous liquid containing regenerated viscose can then be extruded. Extrusion involves passing the viscous liquid through a spinneret or a slit die to produce textile fibres or cellulose films. This type of regenerated cellulose is no longer the same as natural cellulose obtained by defibrating plant matter, and cannot therefore be considered part of paper/cardboard as a material. Although the process is a chemical one, it does not actually modify the cellulose at a molecular level. Regenerated cellulose is therefore not a plastic according to the EU’s SUP (Single-Use Plastics) Directive.
Screenable adhesives: Adhesives which can be eliminated during recycling. They are broken down into coarse particles by the pulper and then removed by the screens.
Stickies: These are fragments of adhesive that stay in the recycling process, resulting in quality defects in the recycled paper, as well as additional machine maintenance and water treatment costs.
SYNTHETIC FIBRES (cellulose): Natural cellulose fibres that have been chemically modified, permanently (modified cellulose) or temporarily (regenerated cellulose), to obtain fibres with different physiochemical properties. Such fibres, even if derived from cellulose, are no longer considered part of paper/cardboard material, except in certain cases, described in the definition of paper/cardboard as a material.