Though the global automotive industry seems to be in shambles, it has not reduced developments on plastics innovation. Automakers have an even greater interest in exploring new materials and processes to deliver lower cost, lighter weight, and more easy recyclable parts and systems. Listed below are a few new developments of plastics in automotive applications:
New Process For Tanks
Twin-sheet blow molding process developed by Inergy Automotive Systems in USA won both the Process/Assembly/Enabling Technologies category and the Grand Award. It eliminates post-mold operations and reportedly can meet the stringent California Partial Zero Emissions Vehicle (PZEV) requirements. It is used for the tank on the 2009 BMW 7 series sedan and has the same six-layer HDPE/EVOH construction as the standard blow molded tank.
A New Blow Molding Application
The industry's first integrated rocker molding and running board, which appears on the 2008 Ford Escape SUV has been developed as a new blow molded application. The rocker molding, step pad and running board are combined in one piece blow molded of 15% glass-filled PP. It is attached to the body side, rather than the underbody, for improved fit and finish. The 1.75-meter-long side mounting, manufactured by ABC Group, Toronto , boasts a stiffness improvement of 56% & weight reduction of 4 Kg.
New Front-End Hybrid
A novel plastic-metal hybrid technique using hydroformed metal tubes won its first commercial use as a structural front end on the 2008 Ford Falcon. In development for at least four years, the new HydroPlast Structures system was developed by Sabic Innovative Plastics and Vari-Form Inc. in USA Pressure-sequenced hydroforming of sheet metal creates a tubular closed section that does not require overmolded plastic ribbing, unlike previous open-section hybrids. The metal tube is overmolded with 30% glass-filled Noryl GTX PPO/nylon from SABIC, and a 3D attachment or SmartLok connection is created between the tube and plastic. Key features include a 20% weight savings over competitive stamped-steel hybrids, reduced packaging space, increased airflow to the radiator, and a cross-car dimensional tolerance of ±1 mm. Other applications such as instrument panels are being explored.
Material Innovations
A new slush-molded TPE for instrument panel skins, said to be the first in North America . The styrenic/olefin blend was developed by interior-components supplier Inteva Products in USA. It performs as well as or better than PVC or TPU at 20% lower weight and without VOC emissions or fogging. It is used on IP skins for the 2008 GM Saab 9-7X SUV.
Another new material development is nanoclays in a new low-mass SMC, said to be the first to achieve low density without using hollow microspheres. It trims weight by 20% in a compression molded truck hood assembly for Navistar International. The hood is based on Arotran 720 polyester for the Class A surface panel and Arotran 740 polyester for the structural reinforcement. Both polymers come from Ashland Composite Polymers. About 200 phr of calcium carbonate filler is replaced with 20 to 50 phr of reinforcing filler and 3 to 5 phr of Cloisite nanoclays from Southern Clay Products. The nanoparticles offer highly efficient dispersion and facilitate micro voiding with less use of low-profile additives. They also provide reduced shrinkage, 15% to 20% greater modulus at high temperatures, and improved surface appearance. The SMC formulation includes acrylic tougheners to improve paint performance. Mechanical properties are maintained despite the lower density, and existing processing equipment is used. The material costs about 15% more than standard SMC.
Other material developments include
* An acrylic pillar appliqué for the industry's first invisible touchpad keyless entry system on the Ford Flex and Lincoln MKS. Atulglas International has developed an improved Plexiglas acrylic taillight material that boasts greater impact and scratch resistance than previous grades.
* A new proprietary TPO developed by Ford and custom compounder Advanced Composites. It sets a new standard for low-temperature toughness in seamless passenger airbag systems for hard IPs. The new TPO on the Ford Focus and Lincoln MKS is ductile at -40 C and meets Ford's stringent cold-temperature impact requirements. The airbag system, injection molded by Automotive Components Holdings USA is less costly and 2 Kgs lighter than comparable soft IP versions.
Modular Floor Console and Shifter Assembly
An exemplified creative product design is a modular floor console and shifter assembly for the Ford Flex. The injection molded structure uses 20% glass-filled recycled SMA to support a floor-based shifter, eliminating the use of metal brackets and hardware previously used to secure the shifter to the floor pan. The integrated system simplifies online assembly, improves fit and finish, and optimizes packaging. Cost is reduced and weight is 2 Kgs less than earlier designs.
New Body Panel Solution
SABIC and Azdel Inc. have jointly launched Ixis 157, a hybrid thermoplastic composite for horizontal body panels. The sandwich structure consists of a 50% random glass-reinforced PP core with two 0°/90° skins of 60% continuous unidirectional fiber-reinforced PP. The skin facilitates a Class A paint finish and maintains dimensional stability while the core aids in processing and reduces overall material cost. The skin is calendered onto the core to produce semi-consolidated sheet, which is typically consolidated into 2 mm-thick parts. The composite is 50% lighter than steel and reportedly offers excellent sound deadening. It has an HDT of 157 C/315 F and is designed for off-line painting. Since the material is designed for low-pressure molding (15 to 100 psi), aluminum tools can be used, resulting in an 85% cost savings versus steel body panels in volumes up to 100,000 parts. The material can be compression molded in 2-min cycles, and low-volume parts can be consolidated in 20 min with vacuum bagging at 200 C.
Carbon-fiber Composites
Carbon-fiber composites made their biggest splash yet in automotive. The Performance and Customization award went to the Class A hood assembly for the 2009 Corvette ZR1, said to be a first for a mass-produced vehicle that meets FMVSS frontal crash tests. The carbon-fiber/epoxy prepreg part has a flexural modulus of 14 million psi and weighs about 12 lb, or about half as much as the SMC hood it replaced. The two-piece structure consists of a six-layer unidirectional Class A outer panel that is painted and an exposed dual-weave prepreg inner panel that is polished to a near-Class-A surface. Also an industry first is the see-through polycarbonate window with a special PUR coating to minimize scratches, fogging, and corrosion. It is bonded to the hood with a specially developed adhesive from Ashland Chemical. The hood is vacuum bagged and autoclave molded by Plasan Carbon Composites. A low-VOC, fast-cure epoxy from ETS, has a built-in UV stabilizer. Plasan cures eight parts in less than 60 min at 140C. Plasan also uses robotic bonding, machining, and auditing systems. Tooling costs under $100,000, about 90% less than molds for SMC. Final part cost is competitive with SMC. Another carbon-fiber hood has been commercialized for the Ford Mustang Shelby 500KR.
Renewable Technologies
An innovative first time use of a soy-based polyol for PUR foam seating. Approximately 12% of the petroleum-derived polyol is replaced with the soy-based version in PUR foam seating for the 2008 Ford Mustang and eight other Ford models. Development partner Lear Corp. blends soy-based polyols in a proprietary process with conventional polyols. The blended formulation releases 66% fewer VOCs and exhibits less fogging than traditional oil-based polyols. For the future, Lear and Ford aim to increase the soy-based polyol content to 25%. Meanwhile, Ford has licensed the technology to John Deere Co in USA and is pursuing other interior foam applications, including headrests; arm rests, and center consoles.
Featuring for the first time is use of recycled TPO in a weatherable appearance part. The air inlet panel on the GMC Envoy and Chevrolet Trailblazer SUV is injection molded of 100% post-consumer recycled TPO derived from damaged auto fascia. The formulation contains about 20% talc.
A proprietary paint-removal process yields recycled material with minimal contamination, a common challenge with recycled TPO. Physical properties are said to be equivalent to those of virgin resin for this non-painted part. The waste that is produced from the water-based recycling process is dried and sold as filler. Cost savings of 2.2% were achieved vs. virgin material and 200 Kgs of landfill-bound material was salvaged.
Expandable PP Foam in Head-restraint Inserts
For the first time, use of steam-chest molded expandable PP foam in head-restraint inserts that meet FMVSS-202a static requirements for a headrest. These are found on several Ford models, including the Focus, Flex, MKS, and F-150 truck. JSP International produces and sells the bead and Tegrant Corp. molds the parts for Windsor Machine Group. Local depressions are molded into the foam core to reduce permanent set during FMVSS-202 backset and height-retention testing. The snap-fit part design is formed without slides or lifters, providing a secure fit to the head-restraint rod and ease of assembly. The part's unique geometry allows for 32 cavities to be molded simultaneously. Tooling costs are significantly less than injection molded or blow molded headrest cores.