600 Chapter Ten ■ Guide rails (for sliding roofs) ■ Lighting components: bezels, brackets, mountings, fog lamps, headlamps, lamp sockets and bases, lenses, reflectors, retainers ■ Liners for pickup truck cargo boxes ■ Luggage carrier rails and hardware ■ Power mechanisms (for doors) ■ Rearview mirror housings ■ Reinforcements and attachments ■ Rocker panels ■ Running boards ■ Trim, trim clips ■ Trunk latches, locks ■ Sunroofs ■ Wheel arch liners TABLE 10.4 Typical Properties for “Derakane” 790 R–65 Epoxy Vinyl Ester Property Value * Glass fiber content percent (wt) 65 † Specific gravity (g/cc) 1.787 Tensile strength, ultimate lb/in 2 (MPa) 27,400 (188) Tensile modulus ksi (GPa) 1,850 (12.71) Tensile elongation percent 1.88 Flexural strength, yield lb/in 2 (MPa) 55,400 (382) Flexural modulus ksi (GPa) 1,850 (12.71) Compressive strength lb/in 2 (MPa) 37,600 (258.4) ‡ Compressive modulus ksi (GPa) 2,120 (14.6) Shear strength (in-plane) lb/in 2 (MPa) 16,400 (113) Shear modulus (in-plane) ksi (GPa) 1,000 (6.87) Shear strength (interlaminar) lb/in 2 (MPa) 4,510 (31.0) Izod impact strength, notched ft-lb/in (J/m) 18.3 (977) Heat distortion temperature °F (°C) >550 (>288) * Room temperature (unless specified otherwise), ATSM test methods (unless specified otherwise). † By glass burnout ‡ IITRI compressive test Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Automotive Plastics and Elastomer Applications 601 ■ Wheel nuts ■ Wheel covers ■ Window guide strips ■ Window support brackets ■ Windows (glazing): fixed and retractable; windshield, side, rear ■ Windshield cowl plenums ■ Windshield wiper bezels, wiper blade holders, wiper pivots Plastic body panels show cost advantages over steel panels, largely due to in-mold painting, in-mold assembly integrating components, and thin-wall resins (higher MFR without sacrificing properties). All three developments significantly lower finished panel costs. Plastic panels have well known advantages on a performance basis—light weight, dent resistance, corrosion resistance, and design versatility. Painting body panels using in- mold colored films (IMCF) with a post-mold clear coating for luster and abrasion resis- tance is increasingly popular as IMCF injection molding technology is further developed. 9 Several formulations have been developed for in-mold coating such as “Xenoy” PC/PBT, “SollX,” “Noryl” GTX, “Surlyn” Reflection series, “Magnum ABS, “Pulse PC/ABS, and “HiFax” propylene polymers. 9,10 These polymers include in-mold paintable grades for in- strument panels, consoles and trim. Fascia, radiator grills (front grill panels), body side moldings, trim, and cladding are injection molded from color compounded “Surlyn.” Re- flection supergloss ionomer/polyamide. 11 The large selection of resins for exterior body panels includes ABS, ASA, PC/ABS, PC/PBT, PC/PET, TPU(E), PC/TPU(E), TPO, polyamides, and thermoplastic polyester blends of PBT/PET. Mineral reinforced blends of PC and polyesters are gaining attention in North America and Europe, providing lower temperature impact resistance, reduced CLTE and automotive class A surface quality for vertical panels, tailgates, and bumpers.“Celanex” UV stabilized PBT, “Ultradur” and “Valox,” provide stiffness, flexibility, dimensional stability, tight tolerance, and weather resistance for injection molding windshield wiper covers. 12–14 In-mold assembly (IMA) to integrate functional components has been gaining industry use as a significant cost-saving process that eliminates post-mold assembly costs. More in- jection molders are using IMA technology, overmolding with multicavity rotating molds, and more self-bonding resins/compounds are available for encapsulation. IMA technology can be used for applications in all automotive segments (e.g., exterior, interior, underhood, and chassis) and for non-automotive applications. “Azdel” glass fiber mat thermoplastic (GMT), with a polypropylene matrix and other thermoplastics, uses chopped glass fiber strand GMT grades for exterior applications such as bumper beams and spare wheel wells. 15 SuperLite “Azdel” grades are available in 2002 for interior applications. Long fiber glass (LGF) composites such as “Compel” and “StaMax” P are gaining more recognition for bumper beams, door structures, instrument panel carriers, integrated front end modules, seat bases and splash shields. 16,17 “Stamylan” P glass fiber and mineral reinforced homopolymer and copolymer PP grades are also specified for battery casings, bumper beams, exterior/interior cladding, HV/AC components, instrument panel/dash- board retainers, interior door structures and underhood containers. 16 “Ketan” TP is injec- tion molded into bumper beams for a number of Audi, Mercedes Benz, BMW, and Ford models; and Mazda 323 bumpers have been injection molded from reactor grade elas- tomer-modified “Kelburn” PP. “Vetron” composites of polypropylene reinforced with up to 75 percent “Twintex” long glass fibers (LGF) are produced by LNP Engineering, a business unit of G.E. Plastics, for exterior and underhood applications, and RTP compounds a line of LGF reinforced com- Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. 602 Chapter Ten posites for automotive and other applications. 17,18 Husky Injection Molding Systems and Krupp Werner & Pfeidler co-developed in-line compounding-LGF composites by feeding continuous rovings into a compounding extruder with polypropylene and other ingredi- ents. 19 Injection molding is a separate step, but it could be added to the in-line process. “Fiberim” TPU(E) composites are reinforced reaction injection molded (RRIM) into bumper beams and panels, seat pans and sun visors. 20 Processes developed with machin- ery companies Cannon (“Interwet”), Engel (“Fibermelt”), Hennecke (“FiberTec” Plus) Johnson Controls Interior (“Fibropress”), and Krauss-Maffei are used to produce LGF composites for automotive applications such as in-mold painted and paintable, bumper beams, exterior panels, front ends, instrument panel (i.p.) carriers, interior door panels, battery trays, seat pans, and tailgate inner panels. Reinforcing fibers can be “Cratec” chopped glass strands produced from continuous glass filaments chopped into specific lengths according to the application. 21 Modular front end systems, hybrid assemblies of plastics and metal, significantly im- prove overall functionality and lower installed cost. Hybrid front end assemblies can be produced by injection molding encapsulating plastics with metal pressings. Reinforced nylon and sheet steel front ends replace all-metal units, providing improved torsional, flex- ural and compressive strength, and help to stabilize the front end section of the car during driving conditions. 22,23 Design can provide uniform distribution of forces such as torque transmitted from the engine. Other advantages of the plastic/metal front end include 40 percent lighter weight than all-steel construction, eliminating the need for tight tolerance joining operations. One process to make these front ends places a perforated deep-drawn sheet steel structure in a mold cavity. Glass fiber reinforced nylon 6 “Durethan” injection molded into the cavity flows through the perforations and around the sheet steel, forming the nylon/steel front end. The process replaces 17 steps with 1 step. A number of components can be integrated with the front end. A typical front end con- sists of nylon 66 or nylon 6 and steel, integrating the bumper, fog lamps, headlights, park- ing lights, radiator grill, and attachments, and even more components can be integrated. The technology can be used for other automotive applications such as front seat construc- tion, and non-automotive applications. DaimlerChrysler Mercedes Benz plastics/metal hy- brid constructions are uniquely used in Mercedes-Benz Division CL-class cars with plastics bumpers, front wings, and trunk lid assemblies; aluminum large surface areas such as hood, roof, rear panel, and rear fender; magnesium inner-door panels; and steel for ar- eas that are high stressed in a crash, cross members, side barriers and roof pillars. 24 The company’s A-class hybrid construction has a “well balanced diet” of plastics, aluminum, magnesium, and steel which includes plastic front fenders. 25 State-of-the art plastics and elastomeric polymers can offer advantages over aluminum and magnesium applications. Bumper beams, fascia, and cladding are molded with thermoplastic polyesters, TPU(E) and TPO(E). Bayer developed “Durethan” nylon 6 hybrid assemblies for front ends and “Bayblend” PC/ABS for hybrid assembly of functional components for exterior panels in- cluding tailgate panels and interior rear seat back rests. 26 Thermoplastic and thermosetting resins, including acetals, LCP, nylons, PC, PBT, PEI, PET, BMC, and SMC, replace metals for lighting components—adjusters, attachments, bases, brackets, bezels, fog lamps, hardware, headlamps, lenses, mountings, parking and backup lights, reflectors, retainers, and sockets. The plastics have good creep resistance and dimensional stability; high-temperature properties such as stiffness at elevated tem- peratures and resistance to hot spots; electrical properties such as dielectric strength and arc tracking resistance; and they are low-cost alternatives to metals and ceramics. Lamp bases and sockets are molded from 30 percent (wt) glass fiber reinforced LCP with high toughness and HDT of 500°F (260°C), 27 30 percent glass fiber reinforced PET, and heat stabilized 30 percent glass fiber reinforced nylon 6 and nylon 66. Headlamp retainers can be molded from 33 percent glass fiber reinforced nylon 66 such as “Zytel” with good Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Automotive Plastics and Elastomer Applications 603 green strength, and 30 percent and 35 percent glass fiber reinforced PET such as “Rynite” using DuPont’s mounting technology. Reflectors are made with metallizable BMC, heat stabilized 40 percent glass fiber/mineral reinforced “Zytel” HTN nylon 66, 40 percent glass fiber/mineral reinforced “Rynite” PET, and “Ultem” PBT for premium priced cars. 28 GE Plastics 3D “Thermal Prediction” software implements headlamp component design, eliminating or reducing the need for prototyping by predicting distortions as a function of temperature increase. BMC, acetal homopolymers and copolymers, nylon 6 and nylon 66, PBT, PC/PEI blends, and PEI copolymers are used for lighting hardware. Heat-stabilized, dimensionally stable, clear (90 percent light transmittance) PC provides a good balance of property to cost for lenses. 29 BMC shapeability and low cost often make it the preferred plastics for headlamp and fog lamp reflectors. BMC reflectors provide a good fit with other components in the light- ing assembly, good metallizing, and heat resistance to withstand headlamp bulb tempera- tures of 392°F (200°C). Nanocomposite-polypropylene with 2.5 percent (wt) reinforcement, compared with about 25 percent talc in conventional mineral reinforced PP, is a harbinger of greater use of nanocomposites for automotive as well as non-automotive applications. Nanocomposites are co-developed for applications such as in-mold painted and paintable vertical panels by GM Technical Center/Materials and Processing Laboratory, Southern Clay Products and Basell/Montell. Vertical body panels show 325,000 lb/in 2 (2.23 GPa) modulus, cladding shows 150,000 lb/in 2 (1.03 GPa) modulus, and lower weight than conventional glass fiber and particulate reinforced composites, without sacrificing properties. Nanocomposites with PP and other engineering thermoplastics include center console, interior door panels, interior trim. knee bolster, pillars. 30 Luggage carrier rail support (roof rail support) assemblies for the ChryslerDaimler Jeep Wrangler have been molded from 40 percent “Cratec” long (0.5 in, 12.5 mm) chopped glass fiber reinforced polypropylene homopolymer. 31,32 The composite is compounded with UV stabilizer and carbon black for enhanced weather resistance. The composite has 1.20 g/cc specific gravity, flexural modulus 994,000 lb/in 2 (6.85 GPa), Izod impact strength notched 7.22 ft-lb/in (383 J/m), DTUL/264 lb/in 2 (1.82 MPa) 315°F (157°C), and CLTE 113 10 –5 in/ in/°F (205 × 10 –5 m/m/°C @ 75–300°F (23–150°C). The rail assembly, integrating several components, snap-fits onto the removable roof. Design and process technologies involve a number of innovations including an insert-molded steel pivot pin, which allows the support rail parts to be folded for easy storage, and patented compression tooling technology. 32 Dramatic changes are taking place with retractable side windows, fixed windshields, and side and rear windows. New glazing greatly improves driver and passenger safety, se- curity, and the sound damping of road and wind noise. Ultraviolet (UV) and infrared (IR) filtering lead to major changes in plastics selection for instrument panel components, seat- ing, and steering wheel covers, and reduced fuel consumption due to reduced air condi- tioning. Not all new glazing composites are “cool glass” that filters out or screens the sun’s IR. Two window products that have been introduced are 1. Glass laminated with “Butacite” polyvinylbutyral (PVB) film interlayer (used for more than 55 years in shatterproof windshields), and “Mylar” polyester film, devel- oped by DuPont 2. Polycarbonate sheet with an organic or ceramic coating, co-developed by GE Plastics and Bayer Enhanced Protective Glass (EPG), “SentryGlas,” and SentryGlas” Plus for side, rear, and roof windows were tested for intrusion resistance and compared to conventional tem- pered glass and polycarbonate sheet. 33 DuPont’s three types of safety glass laminates are Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. 604 Chapter Ten 1. “Butacite” film interlayer in windshields and side windows 2. “SentryGlas” intrusion resistant composite 3. “SentryGlas” Plus, with an ionomeric polymer interlayer for higher impact resistance 33,34 Automotive EPG is constructed of PVB film laminated between two sheets of glass. 36 EPG blocks up to 95 percent of sunlight UV and up to 55 percent of the sun’s IR. This can initially reduce passenger compartment temperature up to 72°F (22°C) in a parked vehicle exposed to direct sunlight. Road and wind noise are damped up to 4 dB. In addition to these attributes, EPG is also intrusion resistant, deterring thieves from breaking into a car, and protecting occupants from being thrown through the window during an accident. 37–39 “SentryGlas” is used in OEM and aftermarkets for windshields, windows, and sidelights. Laminated safety glass (in addition to windshields) is expected to be installed on 1.5 mil- lion vehicles in 2002, compared with 400,000 vehicles in 2000. The Enhanced Protective Glass Automotive Association (EPGAA) was established in September 1999 by Solutia and DuPont for membership by automotive OEMs and glass industry suppliers to “share information and provide overall education on the development of high impact resistant glass.” 35 Solutia produces “Saflex” PVB and Vanceva TM PVB films to complement “Saflex” for security for automotive, architectural, and residential windows. Wedge-shaped “Butacite” PVB film laminated between windshield glass for head-up displays (HUDs) allows dis- plays to show on the windshield. 106 DaimlerChrysler S-class cars, Mercedes Benz coupe models, have laminated safety glass that significantly reduces UV, and a metal coated plastic film liner on the CL-class cars reduces IR. EPG is installed in Audi and Volvo models. “Exatec” Plus injection molded polycarbonate glazing produced by Exatec, a joint ven- ture between Bayer and GE Plastics, was developed initially primarily for side, rear, and sunroof windows. Its construction includes a UV barrier organic intermediate layer, a primer to bond this layer to the PC sheet, and an exterior abrasion-resistant surface coating using GE Plastics’ plasma deposition of silicone coating for abrasion and weather resis- tance or Bayer’s ceramic-type coating using nanomer material technology. The product is lightweight safety glazing with UV and IR barrier properties, break resistance, and sound damping, as well as abrasion resistance. It is intrusion resistant to deter would-be thieves, and passenger ejection resistant during a crash. PC glazing permits style variations with contoured shapes, and the PC sheet can be injection molded encapsulated to produce inte- grated glazing-panels for automotive and building products. A 4 mm thick glazing, same thickness as a typical automotive glass window, weighs 21.7 kg, compared with 43.5 kg for the glass window. Large area seamless PC sheet using process technology developed by machinery manufacturers Battenfeld, Engel and Krauss-Maffei, are encapsulated dur- ing injection molding to produce integrated windows for automotives and buildings. PC windows for automotives will initially be installed in 2003, and produced in high volume by 2007. The International Organization of Standards (ISO) is establishing global stan- dards for automotive glazing using test methods for mechanical properties, clarity, flam- mability, and other properties. 10.2.1.2 Typical interior applications (passenger compartment) ■ Airbags and components ■ Armrests ■ Columns (pillar posts) Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Automotive Plastics and Elastomer Applications 605 ■ Coat hooks ■ Consoles ■ Control knobs ■ Cup holders ■ Digital display housings ■ Door handles ■ Door panels ■ Foot pedal brackets ■ Gear shifts and handle knobs ■ Glove boxes ■ Grills: air conditioner, defroster, heater, speaker ■ Guide rails for sliding roofs ■ Headliner assemblies: skin, foam, substrate ■ Headrest guides ■ HV/AC components, e.g., vents ■ Instrument panel: dashboard components: skin, foam core, substrate, attachments, carri- ers, frames ■ Knee bolster components ■ Light covers ■ Parking brake fittings ■ Rear shelves ■ Rearview mirror housings ■ Reinforcements and attachments ■ Seat belt components: buckles, retractor covers, release buttons ■ Seat components, e.g., back rests, frames, levers (e.g., seat adjustor levers), shells ■ Steering components, e.g., back rests, frames, levers (e.g., seat adjustor levers), shells ■ Steering wheels, columns, switching assemblies ■ Sun visors, sun visor brackets ■ Trim, trim clips ■ Truck trailer liners “SuperPlug” TM inner door panel assemblies, constructed from 30 percent “Cratec” chopped strand glass fiber reinforced PBT/PC “Xenoy,” integrate the window mechanism housing and control, door handle support, armrest supports, speaker mounting, and other system components. 40 Components such as the window regulator, latch, and speakers are assembled off line, according to individual customer specifications. The first application of the inner door assembly had more than 20 variations to meet customer specifications. 40 Chopped strand glass fiber contributes strength, stiffness, dimensional stability, and heat stability; PBT contributes resistance to gasoline, automotive waxes, and cleaners; and PC increases impact resistance over a wide temperature range. 40 Gas assist injection molding is used to produce a hollow channel in the long flow path, increase stiffness, eliminate warpage, and reduce weight. 40 The technology was co-developed by Owens Corning and Delphi Interior Trim and Lighting Systems. Consoles, door panels, pillar trim, and instru- Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. 606 Chapter Ten ment panel component are in-mold painted and paintable and/or low-gloss, high-heat, high-flow, antistat ABS such as “Magnum” and PC/ABS “Pulse.” A foot pedal bracket using glass fiber reinforced “Zytel” nylon 66 replaced steel as it exhibits one-third the weight of steel, lower cost, design flexibility, component integration, and noise and vibration abatement. Plastic accelerator and clutch pedals can be used with the nylon foot pedal bracket. 41 HV/AC control panel knobs on 2001 Chrysler and Dodge minivans are produced by two-shot insert/overmolding injection molding two acetal copolymer “Celcon” grades. The first shot produces white raised lettering; the second shot is overmolded, retaining the white lettering. Melt viscosity and flow properties are key to the flow around the raised let- tering. Breakthroughs for passenger compartment applications are found with in-mold assem- bly (IMA), hybridization (in-mold assembly of plastics and metal components), compo- nent integration and in-mold painting. Instrument panel (i.p.) substrate + foam core + skin are sequentially in-mold assembled during injection molding. Substrates are in-mold painted with TPU, polyester gels, and colored film inserts, and by spray coating the mold cavity. The i.p. is a proving ground for a selection of resins and processing methods. ABS, ABS/PC, PC, PVC, TPO, and TPU are injection molded, calendered, thermoformed, blow molded, and rotational molded into i.p. components. Instrument panel/dashboard designs greatly differ for different vehicle platforms, but they are increasingly favoring IMA, in- mold painting, and component integration including hybrid construction. Calendered TPO skin laminated to polyolefin foam core for lower instrument panels are produced by PolyOne Engineered Film for assembly to the i.p. substrate. The instrument panels are assembled by Delphi Automotive Interior Systems from “Mytex” TPO thermo- formed skin/foam laminates. 42 TPO provides resistance to heat, UV, scratch, ductility, low gloss grain, soft touch, and minimal fogging. “Azdel” SuperLite, with improved weight consistency, available in 2002, has improved weight consistency and surface quality for interior applications such as integrated instru- ment panel components and headliners. 43 Components such as brackets, frames, glove boxes, grills, and knee bolsters are integrated into i.p. assemblies. In-mold paintable injec- tion-molded high heat resistant, impact resistant, low gloss glass fiber reinforced nylon, ABS, ABS/PC, and PC are used for brackets, consoles, frames, inner door panels, knee bolsters, retainers, speaker and defroster grills, and steering wheel covers. High-MFR grades are used for long-flow, thin-wall, complex components. The bar is raised when re- cyclability is designed into resin selection. 10.2.1.3 Typical underhood (engine compartment, under-the-bonnet) applications ■ Air cleaner housings ■ Air injector components ■ Air intake ducts ■ Air intake manifolds ■ Air pump components ■ Baffle plates ■ Battery housings, trays ■ Belts, e.g., drive belts, fan belts ■ Blower wheels ■ Bottles, containers, e.g., window washers Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Automotive Plastics and Elastomer Applications 607 ■ Cable connectors and covering, e.g., control cables ■ Chain guides, chain tensioners ■ Clips/fasteners, e.g., brake clips, fuel line clips ■ Clutch components: clutch cage, clutch cage cap, clutch ring ■ Coil bobbins and spools, e.g., cruise control module ■ Coolant system components ■ Ducting ■ Electronics—connectors, control/sensor housings, throttle control housings, mountings ■ Electrical relay components, e.g., relay bases, cases, coil forms ■ Engine cooling fan blades, shrouds ■ Engine components, e.g., belt guides, engine covers, injector units, rocker covers ■ Valve timing chain covers ■ Emission control system components ■ Fuel cell plates ■ Fuel delivery system components: clips (e.g., to fasten hose in place), fuel dam reser- voirs, fuel filler necks (filler pipes), fuel filters, fuel hose and lines, fuel pump parts, fuel tanks and canisters ■ Hose ■ Ignition coil cases, other ignition system components ■ Oil filter housings and components ■ Oil pans ■ Pipes (water and oil pipes in engine systems) ■ Power distribution boxes ■ Radiator components: caps, support assemblies ■ Rocker covers ■ Sensors/solenoid coils/switches ■ Shrouds ■ Splash shields ■ Support panels, e.g., firewall, radiator ■ Timing chain guides ■ Tubing, e.g., convoluted tubing, vacuum tubing ■ Turbocharger components ■ Valve covers ■ Valve lifter guides ■ Wiper motor housings Upper air intake manifolds are part of a ductwork assembly that directs the flow of air or air and fuel into the engine cylinders. The upper manifold distributes air/fuel mixture through the intake ports into the engine cylinders. Air flow begins with the intake of air from under the hood, initiated by a downstroke of an engine cylinder that causes a vac- uum, drawing in air through the air filter. The filter removes dirt and other particulates from the ambient air. The cleaned air passes through the air intake manifold and enters a cylinder, typically injected in a stoichiometric air/fuel ratio. Air flow and air/fuel ratio are Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. 608 Chapter Ten essential factors in fuel efficiency. Air that is not combusted exits the cylinder with the ex- haust stroke, eventually returning to the atmosphere through the tailpipe. The exhaust manifold collects hot gases from the cylinders and directs the gases into the exhaust sys- tem which is basically composed of the following: 1. The exhaust manifold and gasket 2. Connectors and intermediate pipes 3. Muffler, catalytic converter, heat shield, resonator 4. Gaskets, seals, mechanical clamps, hangers 5. Tailpipe and exhaust pipe Air intake upper manifolds are either lost-core injection molded as a single unit or injec- tion molded in two parts that are subsequently vibration welded together. The latter method, vibration welding two molded parts, is rapidly gaining favor. Twenty five percent to 35 percent (wt) glass fiber reinforced, heat-stabilized, lubricated nylon 6 and nylon 66 are typically used with both processes, although other reinforced engineering thermoplas- tics can be used. 44–46 Bayer high-temperature stabilized, 30 percent glass fiber reinforced nylon 6 “Durethan” and the company’s branched polyamide 6 “Durethan” are two of sev- eral nylons used for vibration welded air intake manifolds. The benefits of plastics over aluminum, which it replaces, are as follows: 1. Lighter weight 2. Cost savings through parts integration, elimination of secondary finishing, and subas- sembly 3. Noise and vibration reduction 4. Design versatility (taking advantage of CAE and FEA) 5. Performance benefits such as smooth air flow through the intake manifold for im- proved air/fuel combustion efficiency Air ducts are produced by sequential extrusion or blow molding alternating rigid PBT sections and soft elastomeric polyester accordion sections, which reduces weight, cost, number of components, and NVH. Underhood electrical connectors are molded from a range of resins from thermoplastic polyesters PBT and PET to LCP, depending on property requirements, particularly tem- perature stability, stiffness/strength ratio, dimensional stability, and chemical resistance. Recent grades have improved toughness and higher MFR for thin-wall, complex connec- tors. Fragile electrical connectors and other delicate electrical/electronic parts are produced by “MuCell” low-pressure injection foam molding and encapsulation injection molding as an alternative to solid injection molding and extrusion. 47 Advantages according to Trexel are as follows: 1. Closer tolerances 2. Improved dimensional stability 3. Low density 4. Low injection pressure, which avoids damage to fragile electronic components 5. Faster cycles Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Automotive Plastics and Elastomer Applications 609 6. Lower clamp force 7. Lower power consumption Electronic sensor and control housings are getting closer to the engine, and attached to the engine’s inner surface. DuPont iTechnology Microcircuit Materials’ “Green Tape” and thick films are used for mounting on and inside the engine for engine control circuits, hy- brid circuits and high density interconnects in 3-dimensions. “Green Tape” is applied to the integration of passive components in 3-D structures, antilock brake system controls, elec- troluminescent backlights for instrumentation on instrument panels, transmission control circuits and rear window heaters. The technologies are used at high operating temperatures for high density circuitry, direct chip attachments. The technology’s mixed analog/digital/ RF and high frequency properties are used for wireless applications, which are being in- stalled on OEM cars and aftermarket retrofits. “Green Tape” and “Fodel” are extensions of iTechnologies’ thick film and thin film flexible “Luxiprint” used for electroluminescent backlights and liquid polyimides used in automotive electronic ignition systems. Electronic throttle control (drive-by-wire) molded from 33 percent nylon 66 “Zytel” re- placing mechanical throttle controls is constructed of a control housing that encapsulates a wire lead frame, plus an integrated outer housing/mounting bracket. Electrical relay components, relay bases, cases, and coil forms make use of a range of engineering thermoplastics, thermoplastic polyesters, nylons, polyphenylenes, LCPs, and thermoplastic polyimide “Vespel” TP can be used for underhood electrical applications due to its high temperature properties, impact resistance, and automotive chemical resistance. 48 The engine is the end point of fuel delivery and air delivery systems, and the starting point for the drivetrain/powertrain system. The fuel delivery system is basically composed of the fuel cap, filler neck (pipe), fuel lines, fuel tank, fuel pump and pump components, filter, upper air intake manifold, and fuel injection unit. Fuel flow through the filler neck and filter can generate an electrostatic surface on the filler neck or filter. 2 For these appli- cations, electrostatic dissipation (ESD) resins are used, such as glass fiber reinforced ESD nylon, “Finathene” and “Marlex” HDPE, which forms a strong weld bond with the multi- layer blow molded HDPE fuel tanks. “Marlex” HDPE, with chemical resistance, creep re- sistance (apparent modulus), ESCR, long-term impact strength, and MFR 5 g/10 min, is blow molded at 379–430°F (193 to 221°C). 49,50 LCPs, high-temperature resins with high MFR such as “Zenite,” are used for the vapor barrier layer in fuel delivery components. Fuel delivery systems must meet California Air Resources Board (CARB) regulations, including Low Emissions Vehicle LEV II, which goes into effect in 2004 and limits evap- orative hydrocarbon emissions to 0.5 g/day maximum—a 75 percent reduction from the regulation in 2000. 51 Other state regulations for evaporative hydrocarbon emissions have been developed. Test methods to measure evaporative hydrocarbon emission as hydrocar- bon loss in materials for components and the entire fuel delivery system are standardized by a joint effort between automotive and materials companies. The methods include 1. Gravimetric screening by the cup method for hose and tubing 2. Specialized permeation conditions 3. Mini-shed 52 Fuel and vapor tubes are typically extruded from fluoroplastics such as “Tefzel” EPTF inner layer and a nylon outer layer. The tubes are temperature resistant above 225°F (107°C) to fuels, fuel vapor permeation, and automotive chemicals, and the retain flexibil- ity above 300°F (149°C). A fuel delivery tube can be constructed with “Viton” fluoroelas- tomer inner layer, “Vamac” ethylene acrylic synthetic rubber tie layer, and “Kevlar” fiber reinforced “Teflon” FEP middle layer. Fluoroelastomers have high-temperature, fuel-resis- tant properties that make them ideal for underhood and chassis fuel delivery components. 53 Automotive Plastics and Elastomer Applications Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. [...]... Plastics and Bayer Registered trademark of Exatec, a Joint Venture of GE Plastics and Bayer Trademark of Exxon Mobil Registered trademark of DSM Engineering Plastics Registered trademark of Huntsman Registered trademark of TotalFinaElf Registered trademark of DuPont Registered trademark of DuPont Registered trademark of PolyOne Trademark of DuPont Registered trademark of Basell Registered trademark of Ticona/Celanese... Registered trademark of Basell Registered trademark of Zeon Chemicals Registered trademark of DuPont Dow Elastomers Trademark of Zeon Chemicals Registered trademark of DuPont Registered trademark of Dow Chemical Registered trademark of Dow Chemical Registered trademark of Mitsubishi Gas Chemical Registered trademark of DuPont Registered trademark of DSM Elastomers Registered trademark of DSM Elastomers Registered... Dow Elastomers Registered trademark of DSM Composite Resins Trademark of Azdel/General Electric Registered trademark of Bayer Registered trademark of Bayer Registered trademark of DuPont Registered trademark of DuPont Registered trademark of EniChem Registered trademark of Dow Chemical Registered trademark of Honeywell Registered trademark of Ticona Registered trademark of Bayer Registered trademark of. .. trademark of Firestone Polymers Registered trademark of Durez, Sumitomo Bakelite Trademark of Dyneon/3M Registered trademark of Goodrich Registered trademark of BASF Registered trademark of DuPont Registered trademark of Dow Chemical Registered trademark of DuPont Dow Elastomers Registered trademark of Goodrich Registered trademark of ExxonMobil Registered trademark of Exatec, a joint venture of GE Plastics... trademark of DuPont Dow Elastomers Registered trademark of DSM Engineering Plastics Registered trademark of Zeon Chemicals Registered trademark of Zeon Chemicals Registered trademark of Goodyear Registered trademark of TotalFinaElf Trademark of Premix Registered trademark of Ashland Chemical Registered trademark of DSM Engineering Plastics Registered trademark of Equistar Chemicals Registered trademark of. .. trademark of Bayer Registered trademark of Dow Chemical Registered trademark of Bayer Registered trademark of Bayer Registered trademark of General Electric Registered trademark of Phillips Petroleum Registered trademark of DuPont Registered trademark of Trexel Trademark of Mytex Polymers, a joint venture of ExxonMobil Chemical affiliates and Mitsubishi Petrochemical Registered trademark of Zeon Chemicals... etherester elastomers and thermoplastic esterester elastomers TEEE (COPE), “Arnitel,” and “Hytrel” are blow molded into transmission and wheel CVJ boots for front-wheel drive (FWD) and rack -and- pinion boots CVJ boots keep grease inside the joints and keep out dirt, grease, salt, and water The TEEE CVJ drive axle boots have a balance of flexibility and stiffness, fatigue resistance to compression and expansion... trademark of Basell Registered trademark of Dow Chemical Registered trademark of DuPOnt Registered trademark of Dow Chemical Registered trademark of TotalFinaElf Registered trademark of Ticona/Celanese Registered trademark of DuPont Registered trademark of Phillips Petroleum Registered trademark of Advanced Elastomer System Registered trademark of DSM Thermoplastic Elastomers Registered trademark of DuPont... Registered trademark of DuPont Dow Elastomers Registered trademark of PolyOne Developed with Ube Industries Registered trademark of General Electric Registered trademark of BASF Registered trademark of BASF Registered trademark of General Electric Registered trademark of DuPont Trademark of Solutia Registered trademark of Dexco, a Dow Chemical/ExxonMobil Chemical Partnership Registered trademark of G.E Plastics... rights reserved Any use is subject to the Terms of Use as given at the website Source: Handbook of Plastics, Elastomers, and Composites Chapter 11 Plastics in Packaging Ruben J Hernandez, PhD School of Packaging Michigan State University East Lansing, Michigan Plastics are used extensively in packaging due to their outstanding physical, mechanical, and chemical properties Plastic are readily available; . fixed windshields, and side and rear windows. New glazing greatly improves driver and passenger safety, se- curity, and the sound damping of road and wind noise. Ultraviolet (UV) and infrared (IR) filtering. synthetic rubbers of choice for weather seals for hoods, trunk lids, roofs, and body seals. 89,90 They are used for sponge weatherstripping and seals for glass run channels, sunroofs, and trunk panels, and. of the Partnership for a New Generation of Vehicles (PNGV), comprising U.S. au- tomotive companies and the U.S. Department of Energy (DOE). 69 Rocker Panels can be blow molded from a number of