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Issue 05/2016

  • Text
  • Bioplastics
  • Biobased
  • Products
  • Materials
  • Fibres
  • Plastics
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  • Renewable
  • Properties
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bioplasticsMAGAZINE_1605_

Polyurethanes &

Polyurethanes & Elastomers New biobased compounds Biobased TPE and PP compounds fulfill the demands of the market The product characteristics of the newly developed biobased TPE and PP compounds correspond largely or entirely to those of their petrochemical counterparts, hence, they can substitute them in existing markets and open up new perspectives. With Terraprene ® , FKuR has brought new TPE-S grades based on a high content of bio sourced raw materials to market maturity. In addition, the recently released Terralene ® PP compounds made by FKuR are partially biobased and currently include an injection moulding and an extrusion grade. The variety of biodegradable and biobased plastics offered in the market has increased significantly in recent years. They are now established in many market segments, are perceived well by consumers and the demand is rising. Some European countries favor solutions with bioplastics so highly that they even require using them by law. Large Brand-Owners have developed strategies for sustainable products and place sustainability increasingly in their focus. Basically, biodegradable plastics do not necessarily need to be made from renewable resources. In contrast, biobased plastics, whose carbon chains are generated from renewable sources, usually are non-biodegradable. Mostly, the biobased plastics offer the same or similar material properties as their counterparts based on fossil materials. In addition, biobased plastics often exhibit properties that biodegradable plastics can only offer conditionally, for example, a high barrier to moisture. Pure biobased plastics, e. g. Green PE (sugar cane based polyethylene from Braskem), have established themselves in certain market segments and are replacing petrochemical plastics there. On the other hand, some biodegradable products are currently on their way to commodity products, e. g. in the form of waste bags, where price pushes quality and unique features into the background. This development stands in contrast to the high development effort these products require. The versatile commodity plastic polypropylenes (PP) as well as the large group of thermoplastic elastomers (TPE) belong to the group of plastics, where biobased types are limited or previously not even represented. Fully or partially biobased TPE The TPE product group comprises the SBS / SEBSbased types (TPE-S), the crosslinked types (TPE-V) and the thermoplastic polyurethanes (TPU), all with their own unique strengths and advantages. Thus, TPE-S grades offer a favorable energy balance; they allow low weight components and injection moulding or extrusion processing with short cycle times. In both cases, they are suitable for the two-component technology, e. g. for processing with PP or polyamide (PA). Through its dynamic cross-linking of the polymer phases, TPE-V provides a higher chemical resistance and lower compression sets. Terraprene is a new biobased TPE-S product line from FKuR with a renewable content of between 40 % and 90 %. Producers using Terraprene can tailor the hardness for the specific application depending on the proportion, between Shore A20 and Shore D40 (Fig. 1). The performance characteristics and resistance properties of Terraprene compounds are similar to those of conventional petrochemical-based TPEs. The goal of current ongoing developments is to increase the renewable raw material portion in the lower Shore A hardness. All Terraprene types can be coloured individually. The density can also be adjusted according to customers’ specifications. For the manufacture of products with unique and noticeable design features (Fig. 2), fillings with wood fibres or other natural fibres are possible. Woody surfaces with a soft touch can be realized this way, thus the visualization of soft and natural surfaces is provided. Partially biobased PP compounds PP, one of the most widely used plastics worldwide, is almost universally applicable, equally suitable for injection moulding, thermoforming and extrusion and unproblematic for recycling. While PP homo-polymers are more stiff and transparent, PP copolymers have good low temperature Figure 3. Comparison of tensile stiffness and Vicat A values of Terralene PP Compounds and typical conventional PP grades. 1600 1400 1200 Tensile Modulus [MPa] Vicat A [° C] 1000 800 600 400 200 0 PP Homo PP Copo (Inject. Mold.) PP Copo (Extr.) PP Random Terrelene PP 2509 Terrelane V 260 48 bioplastics MAGAZINE [05/16] Vol. 11

Polyurethanes & Elastomers properties due to their ethylene content, and PP random copolymers combine high strength with high transparency. Biobased PP grades have an opportunity in the market, if they also bring along these properties. FKuR continues to develop such modified PP compounds for injection moulding and extrusion, with performance and processing characteristics similar to those of the established fossil based PP grades, so that converters can continue to use their existing tools. One of the first products available on the market is the partially biobased Terralene PP 2509. With an MFI of 50 g/10 min (measured at 230/2,16) it is also suitable for producing complex or thin-walled parts with long flow paths. In addition, this grade offers a good impact value, comparable to the value of conventional PP. The partially biobased PP compound Terralene PP V 260 for extrusion applications is still in development (V = experimental type). It combines a low MFI of 7 g/10 min (measured at 230/2,16) with the PP performance characteristics. In Figures 3 and 4, the properties of the new Terralene PP compounds are compared with those of conventional PP grades. As these comparisons show, the modification in both types has little influence on the hardness. Regarding the stiffness, Terralene PP 2509 reached slightly lower values than the pure PP materials, at the same time however, this grade is characterized by its high impact strength. Furthermore, a comparison of the flow properties emphasizes its good suitability for injection moulding. As to the development type Terralene PP V 260, the MFI is currently still a bit too high for a pure extrusion grade. While the typical PP rigidity has already been achieved, the current subject of development is to bring the MFI down. Increased biobased content as a target Since the basic development of the biobased Terraprene TPE-S is already well advanced at FKuR, in this group of materials addressing customer-specific requirements is in the limelight. The Terralene PP grades with biobased contents of 30% to 35% already offer many opportunities to replace conventional PP grades, without compromising the classical PP characteristics. Here, the current priority is the preservation of the PP typical properties, while further increasing the proportion of biobased raw materials. In order to produce integrated biobased plastic products, an overall focus is the combined processing of partially biobased TPE and PP compounds in co-extrusion or 2K injection moulding process. www.fkur.com | 6E48 www.fkur-polymers.com By: Patrick Zimmermann Christian Dohmen FKuR Kunststoff Willich, Germany Figure 1. Influence of the proportion of renewable raw material on the hardness of Terraprene. Figure 2. Terraprene TPE-S grades filled with wood offer a specific look and special surface structure. 100 90 80 70 biobased mass percentage 60 % biobasierter Masseanteil 50 40 30 20 10 0 20 40 60 80 Shore A 20 30 40 50 60 70 80 Shore D 45 40 35 30 25 Tensile Strengh [MPa] MFI [g/10min at 230/2,16] Charpy (notched) [kJ/m²] Figure 4. Comparison of tensile strength, MFI values and Charpy notched impact strength of Terralene PP compounds and typical conventional PP grades. 20 15 10 5 0 PP Homo PP Copo (Inject. Mold.) PP Copo (Extr.) PP Random Terrelene PP 2509 Terrelane V 260 bioplastics MAGAZINE [05/16] Vol. 11 49

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