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Biobased TPE and PP compounds fulfill the demands of the market.

Our valuable speaker for Global Bioplastic Summit, Patrick Zimmermann in collaboration with Mr. Christian Dohmen, sheared their latest article about Biobased TPE and PP compounds fulfill the demands of the market. 

Patrick Zimmermann 

Director Marketing & Sales bei FKuR Kunststoff GmbH and Managing Director bei FKuR Polymers GmbH

More than 15 years of experience in biobased industry! Has been working in FKuR Polymers since 1999.

FKuR Polymers GmbH is focused on the development and production of thermoplastic elastomers and tailor made Polyolefin compounds. To date, they have developed a range of TPE-S (SBS and SEBS based TPE) and Bio-TPE resins for injection moulding and extrusion applications. FKuR product Portfolio offers also PE and PP compounds suitable for injection moulding and extrusion processes. 

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 molding and an extrusion grade.

The variety of bioplastics 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, may be non-biodegradable. “Biobased” does not equal “biodegradable”, the property of biodegradation does not depend on the resource basis of a material. Most non-biodegradable biobased plastics can offer the same or similar material properties as their counterparts based on fossil materials.

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 polypropylene (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 / SEBS-based 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 molding or extrusion processing with short cycle times. In both cases, they are suitable for overmolding 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 set.

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 (figure 1). The performance characteristics and resistance properties of Terraprene® compounds are similar to those of conventional petrochemical-based TPE-S. The goal of current ongoing developments is to increase the renewable raw material portion in the lower Shore A hardness. In addition, the portfolio also includes transparent TPEs of varying hardness. These types can also be produced with materials that are Pharmacopeia approved. Typical applications are hoses, bags or injection-molded components

All Terraprene® types can be colored individually. The density can also be adjusted according to customers’ specifications. For the manufacture of products with unique and noticeable design features (Figure 2), fillings with wood fibers or other natural fibers 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 molding, thermoforming and extrusion and unproblematic for recycling. While PP homo-polymers are more stiff and transparent, PP copolymers have good low temperature 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 molding 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 40 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.

A second injection molding grade Terralene® PP 3505 offers a medium melt flow (MFR 230/2.16 13g/10 min). Compared to a conventional PP grade it offers a good elasticity and higher rigidity resulting in less impact properties. It is suitable for general injection molding applications where long flow paths are not required.

For extrusion blow molding applications, the partially biobased PP compound Terralene® PP 3402 combines a low MFR of about 1.5 g / 10 min (measured at 230/2.16) and a high impact strength. In blow molding processing it shows better welding compared to standard material.

 

 

Terralene®
PP 2509

Terralene®
PP 3505

Terralene®
PP 3402

Melt Flow Index 230/2.16 [g/10 min]

38

13

1.5

Tensile Modulus [MPa]

910

1100

1075

Yield Strength [MPa]

20

25

25

Elongation at Yield [%]

15

14

16

Charpy notched Impact Strength [kJ/m²]

30

6

70

Density [g/cm³]

0.916

0.912

0.922

Figure 1. Overview of mechanical properties of Terralene® PP compounds.

While the typical PP properties and processing have already been achieved, it is still a challenge to combine a higher tensile modulus with good impact strength. The Terralene® PP portfolio will be expanded further, also including grades with PP recylate. These grades combine PP regranulates with biobased materials. However, only high quality regranulates are used. Post-consumer regranulates are used only to a limited extent. Currently, these new Terralene® PP grades are only available in injection molding grades. Further extrusion grades are under development.

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 molding process.

By Patrick Zimmermann and Mr. Christian Dohmen