Additives/Masterbatches By: Christian Lechner Global Technical Segment Manager Plastics BL Advanced Surface Solutions, Clariant Gersthofen, Germany Renewable processing Especially in bioplastics, the origin of processing aids - although used in small concentrations - is more and more considered by the processors and compounders to be ideally also a sustainable and renewable one. However, it is not all about sustainability. The technical demands rise steadily towards lower volatility, higher efficiency and higher thermal stability. New additive solutions help achieve sustainability goals without compromising the high-performance requirements in customer applications With pigment and manufacturing costs continuing to climb, the adoption of novel processing aids and lubricants that improve dispersion – resulting in reduced loadings of costly pigments and increased production rates – is expected to grow. “There can also be seen an increasing demand for solutions that provide excellent heat and colour stability even when used in aggressive processing conditions of high temperature engineering polymers,” says Christian Lechner, Global Technical Segment Manager at Clariant. He adds that improving pigment dispersion is the first target of many Clariant customers. “When they can improve an FPV (Filter Pressure Value) result of a difficult-todisperse pigment from, say, 6 to 2 (bars pressure rise/gram pigment), it opens the door to film and fiber applications, while also allowing a reduction in the dosage of costly pigments needed to achieve the target colour and chroma,” he explains. “An added benefit of the faster production is the reduced need to change extruder screens, while enjoying more consistent and reduced extruder pressure profiles. These two effects reduce the overall cost of materials and production, while delivering higher quality products, which means better physical integrity of the finished articles,” he says. High heat stability – which in this case means resistance to discolouration and volatilization – and a clean initial colour are also needed to allow quick colour matches that stay consistent over long, aggressive extruder runs at the masterbatcher or compounder, Lechner adds. “These requirements are also needed at their clients’ facilities, when they use high temperatures and elevated barrel pressures to assure complete distribution of masterbatches into their polymers and the fastest production rate possible.” Performance is critical. “Lubricants and dispersants must not discolour, degrade or volatilize during the production of final articles that have to pass industry tests on such things as volatility (for automotive interiors) and still maintain a blemish-free surface with the desired gloss or finish,” Lechner explains. Biobased waxes With respect to the higher demand on technical performance and to combine it with the megatrend sustainability, Clariant developed the Licocare ® RBW Vita range based on a renewable feedstock, that are fully competitive alternatives to e.g. montan waxes. Licocare RBW Vita types are based on chemically modified crude rice bran wax. Crude rice bran wax is a by-product from the rice bran oil production. The feedstock of these products is non-food-competing as well as available in nearly unlimited quantities. Licocare RBW products typically carry also Clariant’s Vita designator that identifies solutions that are based on a renewable feedstock and have a renewable carbon index (RCI) higher than 98 %. In addition, the majority of Licocare RBW solutions have been assigned Clariant’s highly demanding EcoTain ® label for sustainability excellence products showing best-in-class performance. The excellent environmental profile of Licocare RBW Vita was also confirmed by the Gold level Material Health Certificate which was recently awarded from the Cradle to Cradle Products Innovation Institute. Filter pressure value (bar/g pigment) Release force (N) 28 20 22 22 23 27 27 516 303 325 427 518 641 750 Without dispersing agent Licocare RBW 102 Vita Montan E Montan OP Licocare RBW 300 Vita PETS Amide Wax Neat PLA Licocare RBW 102 Licocare RBW 300 Montan OP Montan E PETS Amide Wax Figure 1: Filter pressure values while processing a PLA masterbatch comprising 30 % PV Fast Blue BG pigment in Natureworks Ingeo 3001 D PLA and 3 % addition of a variety of different waxes. Test carried out to DIN EN 13900-5; PZ 14um / ISO 9044. Figure 2: Measured demoulding force during injection moulding of Ingeo 3001 D PLA resin containing 3 % of various waxes. Tested to Clariant`s release force test method (internal method). 16 bioplastics MAGAZINE [03/20] Vol. 15
Additives/Masterbatches aids for bioplastics Licocare rice bran wax Rice grain Rice bran Crude rice bran oil Crude rice bran wax Hull White rice Rice Bran Edible rice bran oil Chemical and physical upvalue process Rice Germ Figure 3: Crude rice bran wax is a by-product from the production of rice bran oil. Clariant chemically and physically upgrades this renewable raw material and thus contributes to using the rice grain’s full value. The non-food-competing crude rice bran wax is a by-product of the edible rice bran oil production As a further acknowledgement the Licocare RBW Vita range has been granted the OK compost INDUSTRIAL as well as the OK biodegradable SOIL labels by TÜV Austria Cert GmbH. The certification means that the additives will not compromise the biodegradability of the plastic products and packaging in which they are used. Improved technical performance Clariant’s rice bran wax products show good organic pigment dispersion results, improved mould release properties, and high heat stability in PLA as well as engineering polymers such as polyamides, polyesters TPU, polycarbonates, and urethanes, Clariant claims. The company says they are a premium choice for masterbatching and compounding of functional polymers. In-house trials show that renewable lubricants are not necessarily compromising the high-performance requirements in PLA. The graph in Fig. 2 clearly demonstrates, that Licocare RBW 102 VITA and Licocare RBW 300 VITA provide lower release force compared to the neat polymer and also to best-in-class lubricants like montan waxes which were also used in PLA processing. This lower release force leads to smooth and proper surface and therefore to a better look of the finished article. As a conclusion Licocare RBW as renewable and bio -based additives can also easily convince with better technical performance compared to best-in-class alternatives. In addition, the development of further Licocare RBW grades is ongoing. With Licocare RBW 360 VITA there is also a fully saponified Licocare RBW VITA type available which provides in addition to lubrication also nucleating effect to partly crystalline polymers. This is especially important in injection moulding, as the earlier crystallisation typically leads to lower cycle times with at the same time higher mechanical strength of the compounds due to the higher crystallinity. New enhanced grades based on PLA Clariant has recently announced the collaboration with Floreon-Transforming Packaging Limited to further extend the performance properties and market potential of biopolymers, whilst preserving their environmental benefits. Floreon develops and markets proprietary compounds based on PLA and containing 70-90 % renewable, plantbased raw materials, thus containing carbon sequestered from the atmosphere by plants. They are typically mechanically tougher than traditional PLA and can deliver significant energy savings in processing. By integrating the benefits of Clariant’s additives with Floreon’s proprietary material solutions, the collaboration aims to open up additional possibilities for plastic manufacturers and brand owners to consider biopolymers as a viable, low carbon footprint alternative to fossil-based plastics for both single-use and durable applications. Markets set to benefit from the new enhanced grades include rigid and flexible Packaging, Electrical & Electronic equipment (E&E), Hygiene products, Consumer goods and Automotive www.clariant.com/licocare | www.clariant.com bioplastics MAGAZINE [03/20] Vol. 15 17
