Vehicle weight reduction requirements today pose great challenges not only to automotive manufacturers and suppliers but also to material producers. The materials used must cut weight while at the same time withstanding the mechanical and chemical stresses encountered in service. This can be achieved, for example, with blends of polyamide and polypropylene. These blends also offer other useful advantages.

Fig. 4. Test bars after contact with a calcium chloride solution. The grey points indicate degradation. The bars made from the PA+PP blends show basically no degradation, unlike those made from PA.

16:9

Blends of PP and PA Reduce Weight and Improve Chemical Resistance

Blend

Kunststoff Werkstoffe

Thermoplaste

Kfz-Elektronik

Elektronik

Polyamide

Polypropylen

Lighter Together

Batteries in electric vehicles must be specially protected to counter the risk of fires. Battery trays made from aluminum frequently offer insufficient protection.

To be suitable for the underbody protection of electric vehicles, a material must first pass a bollard test

Underbody Protection for Batteries in Electric Vehicles

Polypropylen-Platten

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Glasfasern / -matten

Verstärkungsstoffe

Automotive

Elektromobilität

Mobilität

Kunststoffe

Photonik

Optik

Aluminium

Metall Werkstoffe

NE-Metalle

Polypropylene Beats Aluminum

Weight reduction is one of the major requirements of automotive components. Regardless of the vehicles in which they are used. One of the lightest materials that can be considered is polypropylene (PP).

The Chinese manufacturer NIO uses carbon fiber-reinforced PP compounds for the center console support of the ES8 electric SUV

PP Compounds for Automotive Lightweight Construction

Polypropylen-Compound

Easier to Reach the Destination

Currently, recyclates are in high demand, including the automotive industry. Previously, component suppliers had reservations about using recyclates in safety-related areas, because mechanical properties varied too widely. Now, materials producer JSP has developed an expanded polypropylene with 25 % recyclate content precisely for these application areas. But to ensure high quality, close cooperation with the recycling company is essential.

The use of expanded polypropylene in vehicles, including safety-critical areas such as passenger and pedestrian protection is vastly increasing

Circular Economy for Expanded Polypropylene (EPP)

Recycling

Umweltmanagement

Kunststoff-Recycling

Kunststoffverarbeitung: Verfahren

Kunststoff-Aufbereitung

Automotive Components  Made of Packaging

To be able to manufacture products from 100 % recycled post-consumer materials (PCR), Avient has developed appropriate colorant and additive masterbatches with PCR matrix.

Especially for packaging, post-consumer recycled percentages of 100 % are increasingly in demand

Verpackungsmaterial

Logistik

Masterbatches

Additive

Farbstoffe und Pigmente

Farbkonzentrate (Batches)

Farbstoffe

Standardkunststoffe

Additiv-Batches

100 Percent Made from Recycling Material

Repsol will build two polymer materials plants at its Sines Industrial Complex, representing the largest industrial investment in Portugal in the last ten years.

Repsol will build a linear polyethylene plant and a polypropylene plant at its Sines Industrial Complex

Polyethylen

Repsol Expands Polyolefin Capacity

Styrenics Circular Solutions (SCS), the value chain initiative to increase the circularity of styrenic polymers, today announced that CEDAP, Compagnie Européenne Des Applications Plastiques, joins the organisation.

SCS develops solutions to combine the benefits of polystyrene in Form, Fill and Seal (FFS) dairy packaging with circularity

Polystyrol

Verbände, Institutionen, Messen

Dienstleistungen

ABS / ASA-Kunststoffe

Polystyrol-Platten

Kunststoffhandel

Handel

Hochleistungskunststoffe

CEDAPJoins Styrenics Circular Solution

Higher mechanical properties with lower density make polypropylene an interesting alternative to polyethylene for a large number of applications. New catalysts and production processes offer a wider range of products. Monolayer films and recycling are under development. In the meantime, China consumes almost one-third of the PP produced worldwide.

The ReOil pilot plant at OMV AG in Schwechat, Austria, converts plastic wastes with poor recycling properties into cracker raw material, and hence into potential monomers

Growth through Sustainability and Technical Specialization

Polypropylene (PP)

The non fossil fuel-based portfolio offers same high quality and performance for applications in all industries.

The Bornewables portfolio is suitable for the production of the most demanding applications, including hygiene and food-contact

Gehäuse aus Kunststoff

Elektromechanik

Kühlkörper

Kunststoff

Bauwesen

Baustoffe

Kunststoff-Regenerate

Kunststofffasern

Borealis Launches Portfolio of Circular Polyolefins

The Danish company Plastix recycles old fishing nets and ropes. The granules produced are used by JSP International, among others, to manufacture expanded polypropylene (EPP).

11 % of the plastic waste in the sea comes from the maritime industry. For the recycling of old fishing nets and ropes, accurate sorting is very important

Expanded Polypropylene from Maritime Plastic Waste

Schaumstoffe und Vorprodukte

Schaumstoffe

Kunststoff-Rezyklat

From Fishing Net to Particle Foam

Milliken & Company will begin production at its new clarifier plant in Blacksburg, SC/UDS, in the fall.

With increased production capacities, Milliken considers itself well equipped to meet increasing demand for clarifiers.

Milliken Increases Clarifier Capacity

Mars Petcare will use Sabic’s BCT18F impact-resistant polypropylene copolymer for the retort pouches of its Sheba cat food brand.

In the future, Sheba wet cat food will be sold in retort pouches with recycled content.

Sustainable Retort Pouches

Innovative leadership through forward-looking technology concepts. ENTEX Rust & Mitschke GmbH is the leading manufacturer of Planetary Roller Extruders. ENTEX owns more than 160 registered property rights for the continuously developed products and additional systems. The product portfolio also includes tempering systems and calander rolls.

ENTEX Rust & Mitschke GmbH  

https://www.entex.de

Aufbereitungsmaschinen

Kunststoffverarbeitung: Maschinen und Komponenten

Biokunststoffe

Compoundieren

Duroplaste

Extrusion

Industrie 4.0

Polyethylenterephthalat

Silikone

Technische Kunststoffe

Temperieren

Wärmebehandlung

Verbundwerkstoffe / Werkstoffverbunde

Current materials and material concepts are reflecting what the plastics processing industry needs: complete solutions for significantly lighter vehicles, better materials for extreme application conditions across all industry sectors, a wider product range, and more additively manufactured plastics. 

Advances and Developments in Thermoplastic Polymers at K 2016 

Megatrends Drive Material Innovations 

Thiele Technologies, Inc., a Barry-Wehmiller company, announces the release of its new Woven Poly Propylene (WPP) Sealer for the Star Series line of bag filling machinery. The WPP Sealer is integrated into the bag filling machine in its own unique station. The sealer is used for sealing step cut paper and poly bags.  These types of bags are commonly used in pet food, animal feed, seed, salt, sugar, fertilizer and chemical packaging applications. The new sealer runs in concert with the UltraStar bag filling system, allowing for bags to be closed seamlessly without affecting production rates. 

New Bag Filling Technology  

WPP Sealer 

Tailgate of the Volkswagen ID.3: Fiber-Reinforced PP Enables the Use of Plastics

Until now, only metal has been used for the tailgates of VW cars. In its top of the line electric model, the ID.3, Volkswagen is now using a plastic-metal composite for the first time. One of the materials used for its production is a long glass fiber-reinforced polypropylene from Celanese. The material was required to not only satisfy the mechanical demands, but also enable an attractive appearance.

The car of the future should be energy-saving as well as low-emission, and at the same time dynamic, comfortable and safe. Consumer wishes such as less maintenance, greater durability and greater environmental friendliness, for example through more sustainable production processes and recyclable materials, round off the requirements profile. Such sophisticated vehicle concepts can only be achieved through further innovations in various areas of automotive engineering. Fiber-reinforced plastics (FRP) are making a particularly important contribution in this respect. They not only reduce the weight of components, but also offer designers great freedom of design.

The first vehicle in Volkswagen’s new generation of electric cars, the ID.3, uses such FRPs from plastics producer, Celanese. The ID.3 is based on a newly developed MEB platform (MEB = modular e-drive system) and is designed purely for electric drive. To increase range and create more interior space without dramatically increasing costs, VW relies on affordable lightweight construction measures.

For example, the steel construction of the tailgate which has been the norm up to now is being replaced in this vehicle for the first time in the VW Group with a plastic/metal hybrid component with visible areas. To satisfy the high rigidity requirements, the main structural part was made from recyclable thermoplastic, long glass fiber-reinforced plastic with metal reinforcing elements. This construction method allows a high degree of design freedom and functional integration. Areas visible to the customer are produced directly with long glass fiber-reinforced polypropylene (PP) without an additional treatment step.

The structural component of the tailgate is a visible part in vehicle interior color. In addition to a good surface quality and the vehicle interior color, the material has to have a low gloss level and good scratch resistance.

The load-bearing structure had to meet crash requirements, as well as rigidity and strength specifications, and offer low distortion and low creep under continuous load and elevated temperatures. To ensure this, metal inserts were planned that had to be sheathed. This required low thermal expansion and a coefficient of expansion as similar as possible to that of metal. Furthermore, the load-bearing structure of the tailgate was to be bonded to the spoiler support. The components were to be tested, among other things, up to 90 °C and the material had to be resistant up to 150 °C. Since the visible area is located inside the vehicle, the odor and emission requirements had to be met for the vehicle interior. In addition, the necessary UV resistance had to be assured for the visible area of the component (Fig. 1).

For the ID.3 tailgate, VW relies on a completely new design concept: the structural parts are now bonded and no longer bolted together. This allows costs to be saved through automation in production. To achieve this, the plastic and the bonding process also had to be coordinated during the material development.

New legal requirements are also increasing the pressure to select materials that can be manufactured in an energy-efficient way and recycled at the end of their life cycle. A correspondingly resource-saving material from Celanese is being used for the tailgate. It comes from the company’s Celstran LFT product family (LFT = Long Fiber Thermoplastics) that comprises long fiber-reinforced PP and, on request, other reinforced polymers. The series also offers further savings potentials. For example, their surface quality is already so good that the polymers can be used without painting in the visible area (Fig. 2). The technology developed by VW and Celanese can be transferred to other lightweight structural components in the visible area.

Celanese has been successful on the market for more than two decades with the Celstran LFT material solution chosen for the tailgate. The desired production of components pigmented in the vehicle interior color, however, is an interesting new development in the field of long fiber reinforcement. With Celstran LFT, the pigment is already contained in the granules and does not have to be added later. That enables the production of visible parts with a very high surface quality. In addition, Celstran LFT is UV-stabilized to prevent color changes when exposed to sunlight. The material has also been emission-reduced for use in vehicle interiors. The complete impregnation of the long fibers plays a crucial role in achieving good surface finishes with long fiber-reinforced thermoplastics. That is achieved at Celanese using the pultrusion technology (Fig. 3) that enables complete fiber impregnation.

With this technology it is possible to incorporate all the additives, such as thermal stabilizers, UV stabilizers and also the pigment into the material in a single process step without damaging the fibers. Lightweight structural components with visible surfaces can be produced by injection molding using this material concept. For light colors, Celanese has also developed an anti-static Celstran LFT grade. This allows contamination due to electrostatic dust deposition to be prevented.

In order to meet the mechanical requirements in terms of rigidity, strength and impact resistance, a PP with a glass fiber content of 40 % was required. The long glass fiber-reinforced Celstran LFT grades of PP, in particular, offer the combination of a low weight and at the same time very good mechanical properties at temperatures from –40 to 120 °C. The particular strength of the long-fiber skeleton is demonstrated under impact loads in the crash test.

UV Protection and Odor Requirements Met with Adapted Formulation

The requirement for a low coefficient of expansion close to that of metals was also satisfied with this choice of material. The thermal resistance in combination with UV protection and the necessary odor and emission requirements presented a particular challenge. For this, the existing formulations had to be revised and a modified new formulation created (Fig. 1). A PP Celstran LFT PP-GF40 in vehicle interior color is used for the tailgate. The rear spoiler support does not have to meet any visual and therefore also no UV requirements. For this reason, a high-performance product for structural parts in black from Celanese could be used for this part (Fig. 4).

Tapes Could Be Used as Substitutes for Metal Inserts

As already mentioned, the high demands in terms of rigidity and crash behavior necessitated the use of metal inserts. The next innovation step could be to replace the metal inserts. The pultrusion technology also provides an interesting option for this. By completely impregnating the fibers with plastic melt, it is possible to roll out the round strands by pultrusion that are subsequently cut into pellets or flat profiles known as tapes (Fig. 5). These are typically produced in thicknesses of 0.25 mm or less and in widths of approx. 300 mm and wound endlessly onto spools.

The progression from a short fiber pellet, to a cable sheath, a fully impregnated long fiber pellet, and finally to a tape is shown schematically in Figure 6. These tapes can then be drawn off the coils at the injection-molding machine, cut to the required length and inserted into the injection-molding machine as “local reinforcements”.

Celanese has extensive know-how in the production of Celstran CFR TP tapes. The tapes can be used in a single layer, for example, as local reinforcements, typically 0.25 mm thick, or in multiple layers, such as four layers with a typical thickness of 1 mm, as inserts. In these cases, they are made of a PP with 70 % unidirectional continuous glass fiber reinforcement. In multilayer processing, different lay angles (e.g. 0°/90° or 0°/45°) can be realized. Since the tapes have the same matrix polymer as the injection-molding material, a unit is formed with the injection-molding material, particularly in the case of local reinforcement without pretreatment. The tapes are then inseparably bonded to the injection-molding material.

Tapes and Injection Molding Material Form a Solid Unit

Long fiber-reinforced thermoplastics such as Celstran LFT are typical materials for modern motor vehicle construction. Their typical matrix materials, PP and polyamide (PA), save weight while the fiber skeleton ensures stability even in molded parts subject to high stress. In addition, these materials exhibit high thermal resistance. This makes them ideal for battery mountings or the battery housing of electric vehicles, as well as for floor panels and instrument panels.

Celanese also offers an extensive product range of short fiber-reinforced materials for electromobility. Celanex PBT polybutylene terephthalate (PBT) has good sliding properties, high resistance to chemicals and weathering, and can be used at high service temperatures. It can therefore be used in connectors for electrical cables. The various Celanyl PA6 and PA66 grades are used for housings and connectors. They are available in the UL94-V0 setting as Frianyl.

The Fortron PPS polyphenylene sulfide (PPS) has long been a proven material in automotive construction and is also suitable for use in electric cars. It is used for pumps for cooling media or fans, but also in coil carriers for electric motors. Actuators are a suitable field of application for the liquid crystal polymer (LCP) Vectra LCP, as are connectors, functional parts for high-voltage applications and components for lighting. The Hostaform POM ECO-B polyoxymethylene (POM) is a sustainable drop-in solution for reducing the carbon footprint in automotive applications. The low-emission XAP grades of this material are suitable for automotive interior applications.

[1] Volkswagen AG, <a href="http://www.volkswagen-newsroom.com" target="_blank">www.volkswagen-newsroom.com</a>, 01.06.2021, ID. INSIGHTS Sustainable E-Mobility, Februar 2019

[2] VDA 2021, <a href="http://www.vda.de" target="_blank">www.vda.de</a>, 20.05.2021

Celanese Services Germany GmbH  

https://www.celanese.com

Ausgabenartikel

The ID.3 is Volkswagen’s first car with a tailgate made partly of plastic.

Fig. 1. The demands on the structural and visible part of the tailgate of the ID.3 electric runabout are numerous. They were met with various material modifications. 

Fig. 2. One part of the tailgate is a visible interior part. The FRP used have a very good surface quality and therefore do not have to be additionally painted. They are supplied as pre-pigmented pellets in the desired vehicle interior color.

Fig. 3. Production of Celstran LFT: the pultrusion technology allows the fibers to be completely impregnated.

Fig. 4. Since the demands on the tailgate and rear spoiler support differ, they were produced using different materials.

Fig. 5. The strands produced by pultrusion can be rolled out into 300 mm wide tapes.

Fig. 6. Schematic illustration of the development of fully impregnated continuous fiber-reinforced tapes: the tapes can be wound onto spools and then processed by injection molding.

KUint4-22_Celanese - Hauptartikel

 Dr. Bernhard Pfeiffer has been global key account manager for the VW Group at Celanese in Sulzbach, Germany, since 2009; <a href="mailto:bernhard.pfeiffer@celanese.com">bernhard.pfeiffer@celanese.com</a>