PLA and PLA resin variants which have a crystalline melting point between 140C and 170C
Flake from thermoformed parts, trim scrap, or cast sheet is amorphous. Flake from oriented film or oriented sheet will be a mixture of amorphous or crystalline fractions, while fibers like staple or spunbond are crystalline. Amorphous PLA flake requires drying at low temperatures (43-55oC) to prevent sticking in dryers. It is the process, the shape and degree of crystallinity, and the percentage of regrind that will determine if the recycled PLA material will need to be pre-crystallized prior to drying and melt extrusion. Recycling crystalline PLA material allows drying at temperatures in the range of 65-85oC. Non-crystallized resin and material with a lower melt point may become sticky in the reclaimer’s pre-extrusion dryer and could prevent the material from flowing through the process. Contaminant materials of a higher melting point remain solid in the reclaimers’ extruder, catch on and may cause blockages in melt screens and contamination in the final product.
The density of PLA is 1.24 g/cm3 and so it sinks in water.
Recycled PLA Content
Depending on the application, a blended recipe of post-consumer and post-industrial PLA is encouraged for products up to the maximum amount technically and economically feasible.