Workshop Addresses How to Injection Mold Bioplastics | Plastics Technology

As demand for bioplastics in products molded from traditional materials grows, injection molders are learning the class of materials presents some unique challenges.

Estimated at $15.57 billion in 2024, the global bioplastics market is expected to grow at an annual average rate of 19.5% from 2025 to 2030, according to Grand View Research, San Francisco, California, with increased utilization in packaging driving global demand. Some perspective is required, relative to the broader plastic market where bioplastics currently represent about half a percent of the almost 414 million metric tons of plastics produced annually, according to European Bioplastics e.V., Berlin, Germany. Despite that and to satisfy the projected growth, global bioplastics production capacity is set to increase significantly from around 2.47 million metric tons in 2024 to approximately 5.73 million metric tons in 2029.

Injection molding of bioplastics, with a particular emphasis on polyhydroxyalkanoates (PHAs), will be the focus of a workshop on Wednesday, March 19, 1–3 p.m., at the PTXPO (March 18-20; Donald E. Stephens Convention Center; Rosemont, Illinois).

Fred Pinczuk of EcoGenesis Biopolymers, Redondo Beach, California, will look at PHA’s history, applications and advantages over traditional plastics, particularly its biodegradable and compostable properties. The presentation will also consider challenges of molding PHA, including rheological properties and material science limitations. The discussion will include the transition some traditional materials such as polypropylene (PP) and low-density polyethylene (LDPE).

Peter Steeves, CJ Biomaterials, Woburn, Massachusetts, will provide an introduction into PHA, including its basic properties. The talk will also address processing PHA through injection molding, touching on potential challenges and possible solutions. The importance of understanding melt flow and the factors that can affect viscosity will be discussed, as well as the importance of mold and barrel temperatures. The presentation will also discuss blending PHA with other biopolymers such as PLA, as well as various fillers, and the resulting differences in processing and resulting mechanical properties.

Finally, Raegan Kelly of Better for All, South Pasadena, California, will discuss her company’s mission to drive a zero-waste movement in the events space. Kelly, head of product at Better for All and a founding member, will share her expertise in developing, commercializing and certifying products made from PHA, including her brand’s award-winning home-compostable PHA party and event cups. The talk will include real-world examples from Better for All’s collaborations with partners and sponsors like USC Athletics, SKYY Vodka and Country Nation.

Learn more and register today.

Beyond Plastic injection molded PHA bottle caps. Source: Beyond Plastic

Because bioplastics are processed at lower temperatures, purging between jobs requires a different process and purging agents than those applied for traditional resins.

Beyond Plastic and partners have created a certified biodegradable PHA compound that can be injection molded into 38-mm closures in a sub 6-second cycle from a multicavity hot runner tool.

Demand for bioresins is growing in molded goods, particularly as a sustainability play to replace fossil-fuel based materials, but these materials are not a drop-in replacement for traditional materials. Molds and hot runners need to be optimized for these materials.