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SAE show highlights: new automotive plastics.

Recycled resins, RIM systems, engineering thermoplastics, and some new processing technologies made news at the annual Detroit expo.

Three dominant trends in automotive plastics manufacturing continued to unfold amid the host of new plastic materials clamoring for attention at the annual Society of Automotive Engineers (SAE) show and conference in Detroit last month.

These same three trends were apparent at last year's SAE meeting (see PT, April '93, p. 67). First, thermosets continue to dominate new plastic body-panel applications, clearly outpacing injection molded thermoplastics. Next, resin producers are looking to new or improved processing technologies to take optimum advantage of existing resin products. Finally, a slow, incremental approach remains the order of the day for implementing commercial programs in recycling plastic auto-parts or using recycle-content resins.

THERMOSETS, THERMOPLASTICS

Thermoset processing by SMC, RIM, and RTM, which was dismissed in recent years by some resin firms as a "mature" field with a recycling Achilles' heel, has outdistanced thermoplastic injection molded body panels by a wide margin. Ford Motor Co. has set the pace among the Big Three in its usage of thermoset body panels (PT, April '93, p. 70). Japanese transnationals have not embraced either species of plastic body panels, choosing to remain with steel.

Dimensional stability of body panels and the ability to meet E-coat paint temperatures are key advantages for thermoset resin systems. Current platforms with extensive utilization of thermoset body panels--such as hoods, roofs, liftgates, doors, bumper beams, and spoilers--include Ford's Mustang, Lincoln Mark VIII and Windstar van; GM's Corvette, Camaro, Firebird and Cadillac DeVille; Chrysler's Viper and Neon; and various truck models and brands.

At the same time, injection and blow molded thermoplastics maintain a healthy pace in new applications for interior parts, as well as under-hood and fuel-system components. Nylon compounds and alloys continue to dominate the latter two areas, with "lost-core" molded engine manifolds developing as a high-growth application (PT, Feb. '94, p. 21). The Amodel PPA line from Amoco Performance Products and long-glass injection molding compounds from various suppliers also have emerged as strong contenders for under-hood components.

NEW PROCESS TECHNOLOGIES

While the pace of new resin development has slackened considerably in recent years, material suppliers have placed greater emphasis on advancing processing technologies to exploit their existing materials in new ways. Among those leading this trend are the Automotive Products unit of Miles Inc., which recently brought out a new infrared annealing process for polycarbonate lighting lenses. Miles first promoted the process for annealing PC medical devices (PT, Feb. '93, p. 13).

Norman J. Brozenick, director of sales and marketing, says the new IR technology is designed to provide a more energy-efficient alternative to hot-air annealing ovens, while eliminating potential environmental and health problems associated with solvents used to relieve the molded-in stresses in PC lenses prior to hard-coating.

The IR annealing system requires about half the capital investment of a hot-air oven, while using substantially less energy, according to Brozenick. It also reportedly cuts the time involved from hours down to seconds. Miles' IR system passes parts on a conveyor through an IR chamber. Hennecke Machinery, a Miles subsidiary, is the system integrator for the technology.

The Plastic Materials unit of BASF Corp. has joined the small handful of resin suppliers, commercial software firms, and academic research institutions that are developing software tools to analyze blow molding (PT, June '92, p. 13; July '92, p. 9; Feb. '93, p. 77). BASF's new computer program, called Moldblow, simulates blow molding of complex-shaped parts. The software, to be provided as a customer service to processors using BASF resins, provides a full computer analysis of parison extrusion, mold closing and the blowing of a part, tooling geometry, part dimensions and material selection.

BASF also has been active in recent years in assisting development of lost-core injection molding technology for engine manifolds. A one-piece air-intake manifold for the new Oldsmobile Aurora uses a new grade of 35% glass-filled nylon 66, Ultramid A3HG7 black Q17 20560, molded by Freudenberg NOK, Manchester, N.H.

Two new vinyl processing technologies were exhibited by the Geon Co., though only preliminary details were revealed. One was a new "skin/foam insert" blow molding technique for interior components that is designed to compete with injection molded ABS or PP parts. The process is said to save material and be able to mold complex shapes.

Geon also showed its new in-mold film lamination system designed to give a metallic appearance to exterior trim of Geon's Fiberloc glass-reinforced PVC (PT, Oct. '93, p. 25). A metal-pigmented film of either PVC or PVDF is bonded to the flexible Fiberloc substrate in the injection mold.

Geon also introduced a new approach to injection molding exterior trim that eliminates end caps and uses new uv-stable and "road-resistant" vinyl grades. The process utilizes molded-in color and new formulations that virtually eliminate yellowing in white pigment.

RECYCLING REALITIES

The hard commercial realities of recycling--including the need for competitive material cost-performance, reliable post-consumer or post-industrial feedstock streams, and a viable collection, sortation, and reprocessing infrastructure--continue to be daunting hurdles for automotive parts recycling. Privately, some resin executives acknowledge that those realities--especially ones involving overall material cost and performance--have slowed recycling efforts and lowered expectations.

The talk today is still mainly of pilot-scale programs and research options and initiatives. The Big Three, through their Vehicle Recycling Partnership, have even created a Vehicle Recycling Development Center in Highland Park, Mich. (see PT, Oct. '93, p. 93). But after three years of discussion, industry groups have yet to commit to a specific commercial-scale program or strategy, or to set numerical goals for industry recycling levels (see PT, May '93, p. 73).

There are two distinct issues under the automotive plastics recycling banner. One is how to successfully utilize post-consumer or post-industrial recycled resins in new automotive components. There have been a few successful demonstrations of the feasibility of reusing in-plant manufacturing scrap, such as "closed-loop" recycling of PC/ABS door panels into rocker-panel supports at Saturn Corp. (PT, Feb. '94, p. 79); recycling PC/PBT bumpers into taillight housings at Ford (PT, April '93, p. 75); and regrinding SMC waste into fresh SMC parts for Chrysler vans and Chevrolet's Corvette (PT, Nov. '92, p. 77' Oct. '93, p. 94).

The latest example to go into production is a 100% recycled urethane air deflector for Chrysler's Jeep Renegade. The deflector is compression molded from pulverized RIM fascia scrap originally molded for Chrysler minivans. Miles first acknowledged this program last year (PT, March '93, p. 80).

This non-appearance part, the first in North America made from 100% recycled RIM plant scrap, is molded by AutoStyle Plastics, Inc., Grand Rapids, Mich., with Miles material and technical assistance. Nothing was added to the ground and pulverized RIM scrap except iron oxide pigment to color it black.

The second and more difficult issue is how to establish a viable industry infrastructure to disassemble cars and collect plastic parts for commercial recycling. In this regard, the Automotive Committee of the American Plastics Council in Washington, D.C., has established a joint project with wTe Corp., Bedford, Mass., for what is characterized as a "Multi-Products Recycling Facility." The pilot program will operate at an existing wTe facility in Boston, and will have the capability to process up to 5000 lb a day, generating flaked and repelletized resin from auto parts and other post-consumer durable goods. The program will focus initially on reclaiming ABS and PP.

The Polyurethanes Recycle and Recovery Council, a unit of SPI's Polyurethane Div., has initiated a development program for recycling post-consumer PUR car-seat and instrument-panel foam (PT, Oct. '93, p. 37). The material is reused in bonded carpet underlay. The SPI program is exploring methods for seat dismantling and foam collection from both post-consumer vehicles and industrial scrap.

RECYCLE-CONTENT RESINS

Although the auto industry may be making halting progress in reusing its own plastic progress, it's asking resin suppliers to develop automotive grades containing post-consumer recycle. One response to that urging is Dow Plastics' new addition to its "Retain" recycled-resin series, this one containing 25% post-consumer ABS. Aimed at non-cosmetic applications, it has a melt-flow rate of 5.7 g/10 min, HDT of 189 F at 66 psi, tensile yield strength of 5270 psi, and notched-Izod impact strength of 2.6 ft-lb/in.

An extension to the Celstran long-fiber product line of Polymer Composites Inc. is a grade composed of up to 90% post-consumer PET. Celstran PETG50-03, with 50% glass and 11-mm fiber length, is aimed at under-hood injection molding applications. Price is about $1.40/lb tl. The recycled PET feedstock, obtained primarily from pallet strapping, is supplied by PCI's parent firm, Hoechst Celanese Corp.

A PCI spokesman says the new recycled grade has mechanical properties and pricing comparable to those of its virgin PP-based Celstran (tensile strength of 18,700 psi, flex modulus of 2.54 million psi, notched Izod of 5.5 ft-lb/in.), but offers a boost in high-temperature performance (HDT of 471 F at 264 psi). However, unlike PP-based Celstran, the new recycled grade requires a hot mold for processing.

MRC Polymers is offering a developmental, 100% post-consumer blend of nylon and PP intended for under-hood connectors, semi-structural brackets, and cowl screens. Salvage 233 is a compatibilized blend containing 30% glass and priced up to 30% less than comparable virgin nylon grades, according to v.p. George Staniulis.

Salvage 233 offers an HDT of 378 F at 264 psi, tensile strength of 9710 psi, ultimate elongation of 9%, and notched-Izod impact of 1.3 ft.-lb/in. Staniulis says MRC also is working on compatible blends of PC and acrylic for automotive lighting.

NEW THERMOPLASTIC GRADES

Dow has two new high-flow ABS grades. Magnum 347EZ (15 g/10 min) has double the flow of Magnum 342EZ at only a small sacrifice in properties. Magnum 385HP (2.5 g/10 min) has easier flow than high-heat TABULAR DATA OMITTED Magnum 357HP (1.6 g/10 min) together with similar or slightly better properties.

The new Lubriloy series from LNP Engineering Plastics Inc., Exton, Pa., consists of nylon 66-based alloys that stand up to high-performance wear applications better than do standard acetal and nylon grades, according to Jamie Tebay, product manager. Two grades are available initially: general-purpose Lubriloy R and high-performance Lubriloy RL. Both are tailored for injection molded gears, impellers, bearings, and motor and locking assemblies. Tebay says two more grades--extrusion and flame-retardant versions--will be brought out later this year.

Compared with standard acetal and nylon 66, Lubriloy R boasts superior wear properties, lower coefficient of friction (both static and dynamic), and a substantially better limiting PV. In addition, Lubriloy R has lower specific gravity than either acetal or nylon 66. Tebay says Lubriloy also offers a wider processing window and less mold plate-out than acetal. Lubriloy R costs $2.45/lb tl, and RL grade is 83.68/lb tl.

DSM Thermoplastic Elastomers introduced the first commercial grade in its Sarlink 4000 TPO series (PP/EPDM). Satlink 4190, with 90 Shore A hardness and ultimate elongation of 556%, is for blow molding air ducts and rack-and-pinion boots. Sarlink 4190 will be priced competitively with comparable Santoprene grades from Advanced Elastomer Systems, St. Louis. This year, the Sarlink 4000 series will gain additional grades that span a hardness range of 40 A to 50 D.

Aerospace technology for attaining structural rigidity and light weight is now available to the auto industry through lower-cost, all-thermoplastic versions of the structural honeycomb products long used in aircraft structures. Made by Hexcel Corp., the new Cecore honeycombs are made of DuPont spunbonded polyethylene, PP, or PET fibers, instead of the aluminum or aramid-paper honeycombs used in aircraft

NEWS IN THERMOSETS

Several new automotive thermosets were introduced by Miles, including an SRIM polyurethane with internal mold release. Baydur STR-IMR is a premium-priced material designed to enhance molding productivity. It's now undergoing production test trials with an unnamed auto builder.

RIMlite is Miles' name for a low-density bumper-fascia material that the company calls "the next generation of PUR RIM." RIMlite is based on Miles' Bayflex 95 PUR system, which is said to utilize "new chemistry" that imparts higher toughness. RIMlite also utilizes proprietary low-density mineral and polymer fillers, affording weight and density savings of 15-20%. RIMlite can be processed on traditional RIM tooling and machines, and will see its first commercial application later this year as a replacement for a traditional PUR RIM bumper fascia on at least one Big Three car model. RIMlite is also expected to compete with existing TPO applications, and offers superior painting properties, according to Miles.

Miles also rolled out an energy-absorbing PUR foam system called Bayfill EA-70. This semirigid foam will be used by a Big Three auto builder to encapsulate an aluminum bumper beam on a 1995 vehicle platform.

Dow Plastics is launching a high-heat addition to its Spectrim PUR RIM line. Spectrim HH reportedly allows exterior panels to withstand paint ovens in the 350 to 400 F range (a sample formulation includes 24% wollastonite filler). Previous Spectrim RIM grades had an upper limit of 325 F.
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Title Annotation:Society of Automotive Engineers
Author:Gabriele, Michael C.
Publication:Plastics Technology
Date:Apr 1, 1994
Words:2177
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