Paperboard Food Contact Declarations and Recycled Fiber Traceability
Food contact safety for recycled board requires functional barrier proof and complete chain of custody documentation down to invoice line items.
Paperboard Barrier Coatings
Protective Treatment
Applied layers of polymers or dispersion-based chemicals on paperboard provide essential resistance against the penetration of liquids and grease. These paperboard barrier coatings prevent external contaminants from reaching the packaged product and keep oils or moisture from compromising the strength of the paperboard. They are typically applied during the converting process or directly on the paper machine.
Functional Performance
Moisture barrier performance is commonly measured as the water vapor transmission rate under specific temperature and humidity gradients. High grease resistance is necessary for food packaging to prevent unsightly staining of the outer box surface. Modern paperboard barrier coatings are increasingly formulated using bio-based polymers to replace traditional polyethylene extrusion coatings.
These alternative materials allow for easier repulping during the recycling process, thereby supporting circular economy goals. This shift towards renewable coatings helps mills reduce their environmental footprint while maintaining the functionality required by packaging brands.
Application Method
Dispersion coating and extrusion lamination are the primary techniques used to apply these protective materials. During dispersion coating, liquid formulations are applied using a blade or rod coater and then dried using infrared heat. Extrusion lamination melts thermoplastic resins and applies them as a continuous film to the moving paperboard web.
Choosing the correct application method depends on the required barrier level and the speed of the converting line.