Low Haze and Antifog Performance of 2-Layer Poly(Lactic Acid) Based Films

For fresh-cut and ready-to-eat packaging films, antifog additives (AFs) are commonly used to suppress the formation of water droplets on film surface. To date, the type and dosage of antifogging for PLA based film are less studied. Therefore, in this research, films incorporated with antifog additive were fabricated by cast extrusion technique. The migration behavior of commercial polyglycerol ester as selected AF was investigated. The cold fog test results showed that 3.5 and 5 wt% of AF in 20PBAT/80PLA single layer film can provide clear films without droplet of water within 7 days and 3 hours, respectively. For 2-layer films, the presented of AF in seal layer as 95(20PBAT/80PLA)/5 (polyglycerol ester) and core layer of PLA were prepared having different thicknesses of seal layer/core layer of 20/15 and 10/15 μm. The migration rate of AF in thin 2-layer film (10/15 μm) appeared to be higher than that in 20/15 μm film. Films’ surface could become clear without water droplet (rating scale > 8) within 4 days for 10/15 μm and 7 days for 20/15 μm films. Haze of films was analyzed by haze meter. Haze of 10/15 μm film was decreased from 7 to 4.4, while that of 20/15 μm film was also decreased from 10 to 7.9 when AF appeared on its surface. Both films can be a peelable PLA based lidding film product with low haze (< 10 %) and antifog performance (within 1 month). In addition, 10/15 μm film can be an easy peel lidding film since its peel strength was in an easy peel range (6-10 N/15 mm).