In situ lamination of starch-based baked foam packaging with degradable films

A technique for making biodegradable food service packaging comprising a starch–fibre core and a biodegradable film laminate is described. The biodegradable films were made of polylactic acid (PLA), polybutylene succinate/terephthalate (PBST), rubber latex and polybutylene adipate/terephthalate (PBAT). The technique involved an in situ process for laminating a baked foam product in a single step. A critical element of the in situ technique involved using a heat insulating fibre sheet to stabilize heat-sensitive laminate films during the baking/lamination process. The PLA-, PBST- and PBAT-laminated samples were baked for 6min at 120°C. The latex-laminated sample, which was much more heat-stable, did not need the insulating sheet and was baked for 3min at 160°C. Starch-based foam laminated with PLA, PBST or PBAT generally had higher density and greater tensile and flexural strength than the non-laminated control. Starch foam laminated with a rubber latex film had tensile and flexural properties similar to the non-laminated control, due to the low modulus and elasticity of the latex film. The in situ lamination process improved the adhesion of the starch foam core with the fibre sheet, PLA and latex films compared to a post-lamination process. All of the laminate materials provided a low water vapour permeance. The films degraded in a compost mixture but at a much slower rate compared to starch. Copyright © 2006 John Wiley & Sons, Ltd.