Packaging breathable-film

Plastic Suppliers Inc., a US extruder of blown film for labels and envelopes, has produced the world s first blown film from NatureWorks PLA. It was hitherto thought that PLA was unsuitable for blown film extrusion. Plastic Supplies claims that its EarthFirst film is 100% compostable, has high gloss, optimum clarity and transparency, high moisture vapour transmission rate, flavour retention, odour barrier, is breathable and is US Food and Drug Administration (FDA) compliant. Areas of application for EarthFirst include window carton film for food packaging, label film, floral wrap film, shrink film and envelope film. 

Other areas where mLLDPE is making an impact are heavy-duty shipping sacks, food packaging (especially fresh produce packaging) (117-120), and breathable films for personal care use, eg diaper backsheet. Elastomers find application as modifiers in LLDPE and ULDPE to improve impact strength, low temperature toughness, and sealability (121). 

A recently patented use in flexible packaging is a three-layer breathable film in which a two-layer blown extrusion of K resin KR 10 and inner metallocene... 

Ecoflex is a thermoplastic material similar to LDPE but with better mechanical properties. It is extruded to make tear-resistant and flexible films for packaging applications. It is resistant to water and is used to make breathable films because of its moderate water vapour permeability. The glass transition temperature of Ecoflex is —30 °C and the melting temperature is 110-115 °C (Yamamoto et al, 2003). Polytetramethylene adipate terephthalate (PTMAT) is made by reaction of tetramethylene glycol with adipic and terephthalic acids. 

Non-breathable applications include wholesale food packaging, especially applications that require freezing products in the bag, monolayer and multilayer films, and vacuum bagging.t ... 

Applications for single- and mnltilayer PS films include food and candy packaging, clear gift wrap, and envelope windows. Because of the ability of PS films to allow gas (such as air) to permeate through them, particularly with higher rubber concentrations, they have been used in breathable produce packaging that provides continued ripening on store shelves [2]. 

Femtosecond laser was also used to ablate polypropylene film with micropattems specifically tailored in size, location and number for breathable microperforated packaging films [99]. 

Micro-perforation has been commercially practiced to introduce high oxygen breathability to film structures for breathable packages. However, the breathable packages with micro-perforation allow egress of moisture to cause the product to dry out. Perforations can also affect the mechanical integrity of the film and potential variability in the gas transmission rate. 

The much enhanced water vapor transmission property allows non-perforated film structure to offer high moisture breathability. This unique performance capability could be used in food packaging applications where protection against contamination and atmospheric moisture control are important. It also provides breathability and comfort to protective apparels where a continuous layer is essential for protection. 

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