SUSTAINABILITY AND INNOVATION
Nelson Packaging is committed to providing eco-friendly packaging solutions. EcoFlex 2 and Eco Flex 5 are recent examples of recycle-ready packaging with barrier.
Nelson Packaging values sustainability and environmental responsibility. Packaging design is geared toward using less material while still maintaining packaging integrity.
We look for the latest industry trends and innovations that help reduce your packaging foot print, improve machinability, and ensure package integrity.
Nelson Packaging always works to provide the best packaging solution. Our team of converting partners are committed to continuous development in packaging improvement.
Power Point below is the Wet Chemistry behind the Eco Flex Barrier coating.
Use of EcoFlex™ Coatings to Create Clear, High-Barrier, Packaging Films
Howard Kravitz, Technology Officer and Fred Levitt, Business Development Manager Dain Nelson, Sales and Service
The following technical specifications describe EcoFlex coatings for packaging films and discusses the benefits (performance, economic and environmental) of using them in place of other optically-clear, barrier packaging materials.
EcoFlex coatings are aqueous dispersions of vermiculite platelets in polyvinyl alcohol (PVOH). The platelets are 1-3 nanometers thick and 10-30 microns in breadth, yielding an average aspect ratio (breadth-to-thickness) of ~10,000:1.
The platelets are maintained in singularized format when dispersed into the PVOH resin and aligned in the plane of the coating when deposited on a film substrate, such as polyethylene terephthalate (PET). The dispersed platelets create a tortuous path for gas molecules, enabling extraordinarily high gas barrier in a very thin layer (0.2 - 0.5 microns dry) with excellent bond strength, clarity and flexibility.
The proprietary formulation also dramatically improves the moisture-resistance of the PVOH resin.
The key technical difference between EcoFlex coatings and past attempts to use nanoclays for barrier enhancement is that the clay platelets remain in singularized format not only when dispersed in the resin, but also during and after deposition. Not only does this achievement enable the tortuous path required for high gas barrier, but it also enables the cohesive strength necessary for multi-layered packaging film structures.
EcoFlex coatings can be applied to a variety of substrates (films, bio-films, papers, and rigid structures) using a variety of standard printing and coating equipment (e.g. rotogravure press, flexographic press, slot die coater, spray coater, etc.).
Applying EcoFlex Coatings
- EcoFlex coatings are manufactured as a two-part system
- A masterbatch of carrier resin and additives
- A water slurry of vermiculite platelets
The two parts are mixed gently under ambient conditions just prior to applying the coating.
- There are several important operating parameters to consider when applying NanoSeal coatings to a film substrate:
- For anchoring the coating on PET, a minimum surface energy of 45 dyne-cm is recommended. For nylon and polyolefins, a primer layer is required.
- Standard anilox rollers can be used. A smoothing bar is also recommended.
- NanoSeal coatings have very low solids content (<10%), so adequate drying capacity is required.
- The heat from drying ovens initiates PVOH cross-linking. Curing, and resultant bond strengths, will continue to improve for up to 7 days.
- A higher-viscosity version of the formulation is available for application using a flexographic press to prevent “slinging” of the coating.
- Because the coating does not heat seal to itself, a sealant layer is required (e.g. polyethylene, cast polypropylene). For example, a polyethylene sealant layer can be extrusion-coated directly onto the NanoSeal coating or laminated to the coating using a solvent-based or solventless adhesive system. Alternatively, the sealant layer itself can potentially be used as the coating substrate.
- Solvent-based inks should be used; water-based inks should be avoided.
Advantages of EcoFlex Coatings
EcoFlex coatings deliver 10-200 times the gas barrier of competing clear materials, such as EVOH and PVdC (see figure at right). Additionally, is not corrosive like PVdC, has better moisture resistance than EVOH, and is not prone to flex-cracking like AlOx or SiOx.
EcoFlex coatings are formulated with different loadings of vermiculite to enable different levels of gas barrier, depending on the requirements of a given packaging application.
In general, NanoSeal coatings yield package structures that are 10-50% less expensive than traditional package structures of comparable barrier performance. Future EcoFlex products will enable even more significant cost reductions by incorporating platelets into other materials (e.g. adhesives, primers, sealant coatings, etc.), thus eliminating entire package layers.
EcoFlex coatings address a number of environmental concerns commonly associated with barrier materials.
First, they enable significantly better gas barrier than alternatives while using 80-90% less material (reducing the amount of packaging material is the US EPA’s top objective in addressing landfill issues).
Second, EcoFlex coatings deliver barrier without the use of free chlorine, which has been increasingly targeted for elimination because of its processing and disposal hazards.
Third, scrap packaging coated with EcoFlex coatings can be re-ground and blended into virgin resin for re-use, unlike some barrier materials.
And finally, NanoSeal coatings do not inhibit the bio-degradability of compostable packaging. Additionally, planned EcoFlex products include barrier coatings using fully bio-based resin systems.
2007 NanoPack, Inc. All rights reserved.