Automotive apphcations

Bisphenol A. One mole of acetone condenses with two moles of phenol to form bisphenol A [80-05-07] which is used mainly in the production of polycarbonate and epoxy resins. Polycarbonates (qv) are high strength plastics used widely in automotive appHcations and appHances, multilayer containers, and housing appHcations. Epoxy resins (qv) are used in fiber-reinforced larninates, for encapsulating electronic components, and in advanced composites for aircraft—aerospace and automotive appHcations. Bisphenol A is also used for the production of corrosion- and chemical-resistant polyester resins, polysulfone resins, polyetherimide resins, and polyarylate resins. 

Fig. 2. Electionic ceiamics foi automotive apphcations. Courtesy of Nippon Denso, Inc.

Because of poor therm oform ability, there are relatively few apphcations for polypropylene sheet. New soHd-phase pressure forming (SPPE) techniques are under development for forming PP sheet. Polypropylene is used in coextmded sheet to some extent for food packaging containers. Glass-filled, wood-filled, or other modified polypropylene sheet materials are used in limited automotive apphcations. 

Heat and oil resistance coupled with its low swell have led automotive apphcations into laminated tubing and hoses (11) with this material. This resistance to the effects of ASTM No. 3 oil at service temperatures of 200°C makes it competitive with fluorocarbons and with the tetrafluoroethylene—propylene copolymer. Fluorosihcones are used to make exhaust gas recirculation (EGR) diaphragms for some passenger cars. 

Automotive appHcations account for about 116,000 t of woddwide consumption aimuaHy, with appHcations for various components including headlamp assembHes, interior instmment panels, bumpers, etc. Many automotive appHcations use blends of polycarbonate with acrylonitrile—butadiene—styrene (ABS) or with poly(butylene terephthalate) (PBT) (see Acrylonitrile polymers). Both large and smaH appHances also account for large markets for polycarbonate. Consumption is about 54,000 t aimuaHy. Polycarbonate is attractive to use in light appHances, including houseware items and power tools, because of its heat resistance and good electrical properties, combined with superior impact resistance. 

EPR and EPDM have been made by either solution or emulsion polymerization processes. More recently a new process involving gas-phase polymerization and metallocene catalysts promises to capture large shares of these markets. These new polymers will be especially attractive in automotive apphcations and wine and cable where theh favorable pricing should be welcome. 

Enichem and DuPont ate two suppHers of acryHc elastomers. It is estimated there ate - 9000 t/yr of these elastomers used in the United States. The principal uses of acryHc elastomers ate in automotive appHcations requiring both oil and heat resistance. These include transmission, valve stem, crankshaft, pinion, and odpan gaskets and seals. In addition hose, tubing, toUs, and belts ate made from acryHc polymers. 

The principal uses of ECO ate in automotive appHcations, eg, for fuel line and fuel vapor recirculation. There ate also some downhole seal appHcations where ECO is used. About 7000 t/yr of epichl orohydrin ate used in the United States. This is aU suppHed by the Zeon Corporation. 

Parts made from fluoroelastomers ate used ia appHcations that justify their high cost, usually where the maintenance and replacement costs are high enough to offset the initial cost of the part. These include automotive appHcations such as valve stem seals, fuel injector components, radiator, crankcase and transmission seals, and carburetor needle tips. Numerous seals and gaskets in the marine, oilfield, and chemical processing industries employ fluoroelastomers. In addition, many hoses in the automotive and chemical industry are made entirely of fluoroelastomer compounds or have a veneer of the fluoroelastomer as a barrier exposed to the harsh environment. Seals and gaskets in military appHcations and the binder for flares and missile appHcations ate made with fluoroelastomers. 

Type 409, developed as a less expensive replacement for Type 430 in automotive appHcations such as trim and catalytic converters, has become the principal alloy in this area. 

In consumer appHcations, titanium is used in golf club heads, jewelry, eyeglass frames, and watches. The Japanese have promoted the use of titanium in roofing and monuments. Other appHcation areas include nuclear-waste storage canisters, pacemaker castings, medical implants, high performance automotive appHcations, and ordnance armor. 

Most cemented-carbide tools are WC-based and have Co as the binder. Other carbide tool materials based on TiC having a Ni—Mo binder were developed primarily for high (>300 500 m/min) speed finish machining of steels and gray cast irons for automotive appHcations. 

Semiflexible molded polyurethane foams are used in other automotive appHcations, such as instmment panels, dashboards, arm rests, head rests, door liners, and vibrational control devices. An important property of semiflexible foam is low resiHency and low elasticity, which results in a slow rate of recovery after deflection. The isocyanate used in the manufacture of semiflexible foams is PMDI, sometimes used in combination with TDI or TDI prepolymers. Both polyester as well as polyether polyols are used in the production of these water-blown foams. Sometimes integral skin molded foams are produced. 

The use of calcium carbonate in thermosets continues to grow as these plastics replace alternative materials, especially in automotive appHcations. Increased loadings of calcium carbonate in thermosets reduce cost and provide better surface characteristics. 

With higher mol ding speeds and higher temperature resins, the demand for thermal stabiUty is increasing. As plastics replace metals in automotive apphcations, weatherabihty and service-temperature requkements are sharply increased. SuppHers are responding with improved products. 

The excellent properties of these fluoroelastomers come with a high price tag. Kalrez, for example, is extremely expensive ( 33—44/kg). These materials are used in automotive appHcations (seals, gaskets, fuel hose lines, engine parts, etc), where they can withstand under-hood temperatures. They are also used in equipment for oil and gas production and chemical processing. U.S. consumption in 1988 was 3100 t (76). 

If a need is met by a variety of products, then the price should reflect the price of these competitive products and any unique or advantageous features of the product being priced. For example, some plastic parts for automotive appHcations can be priced higher than corresponding metal parts because of lighter weight, corrosion resistance, or other features. 

The main uses of EPM of EPDM are in automotive appHcations as profiles, (radiator) hoses, and seals in building and constmction as profiles, roofing foil, and seals in cable and wke as cable insulation and jacketing and in appHances as a wide variety of mostiy molded articles. 

Considerable amounts of EPM and EPDM are also used in blends with thermoplastics, eg, as impact modifier in quantities up to ca 25% wt/wt for polyamides, polystyrenes, and particularly polypropylene. The latter products are used in many exterior automotive appHcations such as bumpers and body panels. In blends with polypropylene, wherein the EPDM component may be increased to become the larger portion, a thermoplastic elastomer is obtained, provided the EPDM phase is vulcanked during the mixing with polypropylene (dynamic vulcani2ation) to suppress the flow of the EPDM phase and give the end product sufficient set. 

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