Funding Opportunities with Industry

Recyclable materials with vapor barriers for paper-based food packaging

Background

The current paper-based packaging for dry and wet foods; like coffee, powdered infant formula, chips, cookies, dough, or sour cream; are complex multi-component structures. They have foil and/or layers of different materials, that work well for protecting food freshness during transport and shelf life, but they are not widely recyclable. The packaging materials can impact sortation in a materials recovery facility to a paper stream, but more importantly, they can limit the amount of useful recovered fiber and contaminate repulping processes.

Packaging structures with high paper content can be recycled, repulped or composted but may not provide the food enough barrier protection to stop oxidation due to oxygen or degradation from moisture in hot and humid environments. It is challenging to achieve the very high moisture and oxygen packaging barriers required to preserve food freshness through transportation, shelf life and home use.

What we're looking for

Sonoco is seeking barrier materials, coatings, films, structures or components therein, for paper-based rigid can and flexible food packaging. The barriers must reduce oxygen and moisture vapor transmission while maintaining food freshness during transportation, shelf life and consumer use. Technology that improves surface or coating characteristics of the paper for subsequent barrier materials is also of interest.

Solutions of interest include:

Paper with barrier materials applied during paper formation
Paper with a smoother surface or improved holdout to immobilize subsequent coating materials on the paper surface.
Barrier materials that form part or all of a coating, film, laminate, skin layer
Barrier materials that are applied to a paper as a coating in flexographic or gravure processes or extrusion laminated
Barrier materials that can be applied directly to the paper by other technologies

Our must-have requirements are:

Oxygen transmission goal is 0.3 to 7 cc/m2 per day at 23C and 0%RH and water vapor transmission goal is 0.15 to 7 g/m2 per day at 28C and 80% RH.
Can be incorporated into/applied to paper that is 22-280gsm.
Maintain barrier properties when the paper is folded, curled or creased. A single Gelbo Flex can be used to test barrier integrity against folding.

Our nice-to-have's are:

FDA approved for primary or secondary food packaging or capable of compliance to food contact regulations (21 CFR 174-183) as applicable and specific per the materials used.
Repulpability certificates from Western Michigan University (https://wmich.edu/pilotplants/recycling/certificates), Wisconsin Institute for Sustainable Technology (https://www.uwsp.edu/wist/Pages/laboratory-services/testing-services.aspx) or equivalent.
Does not add more than 18gsm to the rigid paper can structure, or 28gsm if a heat sealable layer is included.
A 10gsm or less heat seal adhesive layer providing of >2000 Grams force/in or fiber tear.
A heat seal layer with coefficient of friction < 0.25 of coating to steel or coating to coating as per ASTM D1894-73, Procedure B.
A solids content >30wt% and the viscosity 200-600cp for coatings that would be applied to the paper packaging surface by Sonoco in flexographic or gravure processes.
A film thickness of 6-12lb/ream thick for materials that would be extrusion laminated by Sonoco to the paper packaging surface.
A grease barrier of 12KIT (most aggressive).
Allow 2-8% elongation in both the machine and cross direction of the coated paper.

What's out of scope:

PVDC, PFAS
Cannot create stickies or micro-polymers in repulping
Biodegradable/compostable materials are not of interest for rigid paper cans but may be considered for some flexible paper packaging formats

What we can offer you

Benefits: