Oxygen and moisture barriers ensure the sanitary storage and transportation of food and medical supplies, but even the tiniest imperfection can compromise the package. Additionally, there is the ever present concern of environmental impact. Such factors are what producers must consider when searching for ways to improve these barriers.
Perfecting Polyethylene
Polyethylene (PE) makes up the bulk of most films. There are several ways PE can be optimized in barriers. A higher density PE provides a better moisture barrier. A higher melt index and/or narrower molecular-weight distribution also improves barrier properties of PE. High melt index and narrow molecular-weight distribution resins are less sensitive to changes in processing conditions and contribute to a balanced crystalline orientation.
Multi-layer PE films are affected by layer position. Each layer experiences different conditions during extrusion. A film’s outermost layer must be able to withstand more intensive shear and cooling forces than interior layers. The proper melt index and molecular-weight distribution contribute to this improved layering.
Plugging Pores With Nanotechnology
Nanotechnology might prove to be the future of oxygen and moisture barriers. Nanotechnology is what contributes to the ultra-high barrier properties of a “micro-pore-plugging” film from Tera-Barrier Films Pte, Ltd. This film claims to offer moisture barrier performance 10 times better than transparent oxide barrier films.
Conventional plastic films have imperfections such as pinholes and cracks. Using reactive and nonreactive nanoparticles, the micro-pore-plugging films seals these defects. The nanoparticles actively react with and retain moisture and oxygen.
Compostable Oxygen and Moisture Barriers
While performance is certainly an important aspect of improving oxygen and moisture barriers in packaging, environmental impact is also something to consider. BASF has developed a completely compostable multilayer food packaging barrier film. The technologies include film resins, inks, adhesives, and primers. The six-layer film consists of a compostable polyester film, a printing ink layer, an adhesive coating, a metallization layer, a premetal primer, and another compostable polyester film. The finished product meets all food packaging barrier requirements. This new and improved film can go directly to composting sites rather than a landfill.
When improving properties like oxygen and moisture barriers in packaging there is so much to consider. A producer must sometimes do as best they can with the material available, the cheapest material, or the most popular material. A product can be revolutionized and perfected, yet there will always be a drawback. The most effective product may not be the cheapest or the most environmentally friendly.
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