November, 30, 2021 - Wacker, the Munich-based chemical group, is showcasing two additives for processing biodegradable plastics at the 16th European Bioplastics Conference: its Vinnex additive system based on polyvinylacetate technology and its silicone-based performance additive Genioplast for thermoplastics and engineering plastics. Both additives enhance the processing and material properties of bioplastics. Latest tests show that the products are even more effective when combined. Wacker will present its test findings at the conference, which runs from November 30 to December 1 in Berlin, Germany.
The Munich-based company chose the biopolyesters polylactic acid and polybutylene succinate as representatives of biodegradable plastics for its screening. While biopolyesters are, in principle, considered alternatives to conventional thermoplastics, they are difficult to process and require suitable additives to achieve the property profile customary of thermoplastics. The additives examined were Vinnex 2504, Vinnex 2525, Genioplast Pellet S and Genioplast Pellet P plus.
The key finding of the screening is the observation that Vinnex and Genioplast complement each other in their effects – in both filled and unfilled bioplastic systems. When used together, the processing and performance properties of bioplastics can be optimally adapted to the specific requirements. But there is also another advantage: both additives are more effective when they are used in combination than when they are used separately. Depending on the grade used, Vinnex either has a particularly positive influence on the polymer melt or on the mechanical properties. The additive ensures that bioplastics can be processed without difficulty. Mixed in with Vinnex, Genioplast primarily affects the surface properties of the plastic item, especially in filled systems.
In the bioplastic samples that were tested, Genioplast acts as a booster and enhances the effects achieved with the Vinnex additive which had been previously added. In several cases, the silicone additive also improves properties that Vinnex has no influence on. It is the addition of Genioplast that reduces surface friction, thus increasing the bioplastics’ scratch and abrasion resistance. This was verified by examination of the depth and roughness of scratches with a confocal microscope.
The unique additive combination furthermore improves the mechanical properties of the final article. Used together, Vinnex and Genioplast boost the flexibility and impact strength of bioplastics and, in filled systems, increase elongation at break without impairing thermostability. Plastics modified in this way are thus suitable for applications previously reserved for conventional thermoplastics.
When added in the usual amounts and depending on the individual system, Vinnex and Genioplast additives do not hamper the degradability of biopolyesters such as polybutylene succinate, polylactid acid or thermoplastic starch and combinations of these biodegradable polymers.
Vinnex and Genioplast Pellet
Vinnex additives were specifically developed for modifying biopolyesters and starches. These homopolymers, copolymers and terpolymers are based on polyvinyl acetate.
Vinnex 2504 is a powder-form polyvinylacetate-ethylene copolymer. As a soft plastic, it increases the impact strength of bioplastics. Unfilled polylactic acid modified with Vinnex 2504 is opaque.
Vinnex 2525, a resin available in granular form, is a polyvinylacetate homopolymer. It acts as a production aid. Biopolyesters modified with Vinnex 2525 are particularly suitable for producing packaging films by blown film extrusion. The additive leaves unfilled polylactic acid highly transparent.
Genioplast Pellet S and Genioplast Pellet P plus are silicone-based plastic additives in pellet form. Both grades are universally suitable for compounding all thermoplastics. As active component, they contain a non-crosslinked ultra-high-molecular silicone polymer mounted on pyrogenic silica. Genioplast Pellet P plus is approved for food contact and Genioplast Pellet S is the respective grade for technical applications. Both grades reduce friction. They thus act as production aids and enhance the plastic’s end properties.