The latest news from the world of Bioplastics

By Vladislav Jaso, TotalEnergies Corbion

Polylactic Acid (PLA) is well known for its widespread utilization in packaging, particularly within food packaging. However, PLA’s versatility extends beyond traditional packaging into many domains like nonwoven materials, 3D printing, and durable applications. In the durable market segment, compounds made from PLA and other additives have consistently demonstrated their efficacy in a wide range of products.

Compounding consists of preparing plastic formulations by mixing and/or blending polymers and additives in a molten state to achieve the desired characteristics. The process of PLA compounding is similar to the creation of compounds from traditional plastics. The most common compounding machines are co-kneaders and twin screws extruders (co- and counter-rotating) as well internal mixers. The extrudate, which look like long plastic strands, is then cooled in water, in a bath or by spraying, as they move to the pelletizers.

Like with other plastics, it is imperative to ensure the PLA material is properly pre-dried and the machine is adequately purged before compounding. Luminy® PLA can be processed on standard compounding equipment. For optimal results, the employment of a co-rotating intermeshing twin screw extruder with a L/D ratio of at least 28:1 is recommended.

A typical extruder setup and temperature profile for compounding PLA compounds. The use of a mild screw design with mixing sections after each addition port is recommended.

Depending on the formulation, standard side feeders and liquid feeders can be used. Degassing is usually essential to ensure the best performance of the final compound, by removing possible volatiles caused by the introduction of additives or fillers. Conventional pelletizing technologies can be used such as strand and underwater pelletizers.

A good example of an innovative compound application is cosmetic containers made from TotalEnergies Corbion’s Luminy® L105 injection molding grade, filled with wood chips and natural biodegradable binders. These articles made from PLA compounds offer a stone or wood-like appearance along with good processing economics and combine ecology, luxury, and virtually unlimited design possibilities.

Another interesting application of PLA compounds is panels for outdoor road signs. A Dutch producer combines Luminy® PLA resins with industrial hemp fibers to produce strong, yet lightweight panels.  The panels are suitable for indoor and outdoor use and come with a 10-year warranty. At their end of life, they can be mechanically recyclable. Their carbon footprint is 99 % lower than the common alternatives, made from aluminum.

Children's toys are yet another application for PLA compounds. Suitable formulations enable biobased, recyclable as well as durable toys with good impact and heat resistance. Toys made from PLA compounds have excellent surface finish and are easily customizable in terms of color, making it exciting for the end user without compromising on quality or sustainability.

Luminy® PLA is a sustainable alternative for conventional plastics. In the durable segment PLA satisfies the technical requirements of many applications. Its environmental advantages make it a future proof material to support the transition to the low carbon economy. Start your journey with PLA, contact us to discover how we can work together.