Styrenic polymers in automotive interior and exterior

At the recent Automotive Interiors Expo in Germany, Styrolution put its focus on decorative materials in interior where styrenic polymers have become the material of choice for a wide range of applications. Styrenic polymers can already be found in a sizable number of exterior applications as well. We talked to Pierre Juan, Global Vice President Automotive at Styrolution, to learn more about Styrolution, the styrenics market and new applications.

styrenic polymers at Fiat

Exterior: high gloss – unpainted

While there is a definite trend towards high-gloss exterior parts such as front grills, B-pillars, rearview mirrors, rear lights, exterior panels and trims, manufacturers are looking for unpainted solutions in order to reduce costs. In addition to the usual surface aesthetics, the materials have to meet requirements related to scratch resistance and UV stability. Typical unpainted parts in exteriors include the front grill, roof trims and rearview mirror housings. Different materials or material combinations can be used depending on the specific requirement of the manufacturer and the decision whether or not to paint.

  • ASA (Luran S) can be used for unpainted parts. This material features very good weather resistance and good dimensional stability. For example, the Fiat Group uses this grade with a high-performance UV additive and has replaced a previously used (painted or unpainted) commodity polymer for all unpainted exterior applications across its car models worldwide. The material will be used in a number of exterior applications, ranging from rear view mirrors, emblems and front grills to B-pillars and roof rack bars. Another company, DAF Trucks, was one of the early pioneers to replace sheet moulding compound (SMC) with this ASA grade on their entire exterior cabin.
  • ASA/PC (Luran S/C) can also be used for unpainted parts and features higher impact strength and a more enhanced thermal stability than ASA.
  • ABS (Novodur) is usually painted in exterior applications. This ABS grade features high paint adhesion, in addition to good heat stability and impact resistance.

The same materials and material combinations are also used in front grill applications, either painted, unpainted or electroplated. Typical electroplated parts can be found in emblems and door handles and come in high-gloss, low-gloss and matte finishes. Electroplatable ABS grades, such as Novodur P2MC or PC/ABS blends like Novodur Ultra 4140PG, feature high flowability and very good surface adhesion. If the material is used in crash sensitive zones on a car, then a blend containing polycarbonate is often used due to the higher impact resistance.

ASA grades can also be deployed in combination with in-mould decoration to produce parts with special effects, such as the diamond radiator grill on the MercedesBenz A-Class. This application was even honored with an award by The Society of Plastics Engineers (SPE) in the body exterior category last year. The grill is moulded by Magna Decoma using the ASA grade Luran S778T. The chrome-effect pins are hot stamped with a sophisticated five-layer film from Leonhard Kurz.

Interior: trend towards light colours

In interior applications, automakers are continuing to look for ways to differentiate themselves from the competition through design. There is a trend towards light-colored interiors, such as light gray or beige, and the use of transparent light guides and light diffusors. Here too, painted and unpainted solutions are available.

Styrolution also offers a material blend for unpainted interiors ABS/PA alloy (Terblend N).Components made of this blend, either unfilled or glass reinforced, feature a matt surface with good haptics. Due to the strong flow properties of the new range of Terblend N “EF” (Easy Flow), very fine surface structures can be reproduced in the injection moulding process, while weld lines or flow front lines are invisible.

A new material for unpainted interior parts is an ASA/PA blend, Terblend S. It is particularly well suited for interior trims, parts above the belt line or in convertibles where light and brightly coloured parts are exposed to UV radiation. Terblend S was used, for example, in the Renault Zoe. Main features include good UV resistance and high impact strength. Parts made of this blend do not squeak and rattle due to its favorable acoustic properties.

styrenic polymers in interior

Transparent material for lighting

Lighting and light diffusors are another trend in high-end car interiors. Styrolution is currently evaluating a number of its transparent products, such as Luran (SAN), Terlux(MABS) and NAS (SMMA) for automotive interior applications. Luran, for example, can be used to produce large and long parts due to the good flow properties during processing compared to rather slow flow of other materials. The product is currently used by the company Angell-Demmel to produce scuff plates employed in the new Audi.

Styrolution: 17 production sites worldwide, reinforcing its presence in Latin America & India

Styrolution’s products range from styrene monomer, PS, ABS, ASA and SAN to SMMA (styrene methyl methacrylate) and SBC (styrene-butadiene block copolymers). With 17 production sites in ten countries, Styrolution is the only styrenics pure play on the market with global reach. This is of particular importance for world-wide operating plastic parts manufacturers as they have to meet the global OEM standards wherever they produce.

New investments in key markets for automotive are currently under way, including Mexico (AMSAN), Brazil (ABS Standard/SAN specialties as part of a planned joint venture with Braskem) and India. In India, where the company is already the leading ABS supplier, Styrolution just inaugurated a new 40,000 mt line for Absolan SAN at its Katol site located in Gujarat, India. The move to increase domestic supply of styrenic specialties in India goes hand in hand with Styrolution’s so-called Triple Shift growth strategy which was launched in August 2013:

  1. Focus on higher growth industries (such as automotive)
  2. Expanding the company’s market position in styrenic specialties and ABS Standard
  3. Expansion of footprint in emerging markets

(based on an interview with Pierre Juan, Global Vice President Automotive, Styrolution)

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