Less Visible, More Remarkable

The use of plastic in automotive applications continues to grow, although not at the white-hot pace it did during ’80s and ’90s when each model year produced hosts of new interior and exterior plastic parts. Today, new automotive plastics applications are more specialized and exotic, representing the incremental advancement of material performance and vehicle engineering. Typically, such applications come to fruition after long periods of partnering and development work and significant capital investments.

Perk for plastic: hybrid parts

“If you look at the auto industry, plastic has been an incredible success story,” says Bob Nelson, GE Plastics global marketing manager, automotive. “But all the easy, no-brainer stuff has been done.”

Nelson believes the next generation of new automotive plastics applications will be driven by methods that incorporate multiple materials, such as plastic-metal hybrid technology. In one application, GE is combining metal with Noryl PPX, a blend of PP and PPO, to build an under-hood structural carrier. Nelson describes the Noryl grade as a fit between polypropylene and nylon in terms of cost and performance. GE’s method of combining metal and plastic is patent-pending, and the part is still in development.

Says Nelson: “The metal allows us to optimize the part from a structural standpoint, and the plastic provides design flexibility and optimizes part consolidation.”

The net result of hybrid technology is often a part with a combination of properties that cannot be achieved by either of the respective materials alone. Steel provides ductile behavior during crash and the ability to shape flat, deep-draw parts that can be punched or drilled. Plastic contributes design freedom, weight savings and corrosion resistance.

Bayer Plastics developed the first commercial metal-hybrid applications working with a number of automotive OEMs throughout the 1990s. Parts made with this patented hybrid technology consist of thin-formed sheet metal profile supported by ribbing made from Bayer’s Durethan polyamide. The resin is mechanically linked to the metal during injection molding. The company’s tests have shown that composite metal-plastic materials can have a higher load capacity than open or even closed metal sections. The technology has been applied to produce front-end modules for Ford Focus resulting in a 40% reduction in part weight and a 20% reduction in part cost.

Tweaking the inner car

Long the domain of plastic, vehicle interiors nonetheless continue to evolve as designers seek materials with an improved balance of aesthetics, cost and performance.

HVAC control knobs made from Ticona’s Celcon UV140LG acetal copolymer won a finalist award at the Society of Plastics Engineers Automotive Division 2002 conference under the category of “Most Innovative Use of Plastic”. The knobs are made by TRW for Chrysler- and Dodge-branded minivans. The grade of Celcon used for the knobs has 80% less gloss than other acetals. The low-gloss grade allowed TRW to meet the stringent 2% gloss and color match to other IP components without the use of paint.

The knobs are made by first injection molding an undermold of white Celcon acetal copolymer formed in raised letters to indicate the function of the knob. Originally, the design had called for overmolding this part with 1.5 to 2 mm of 20% glass-filled black nylon. The nylon, however, had excess gloss and also generated enough shear heat during molding to deform the lettering. As a result, designers turned to Celcon acetal for overmolding also. The resin flowed well during overmolding so the raised lettering stayed sharp.

GE Plastics is introducing a new molded-in color resin designed to enhance the aesthetics and performance of interior plastic parts. The new resin, trademarked under the name Cytra, is a PC/PET blend targeted to replace polypropylene in applications requiring high-heat and structural performance properties. The material is being targeted for parts that do not have a skin, but are subjected to high heat or loads, such as door pillars, trim and upper portion of the instrument panel.

“We’re optimistic about this material,” says GE’s Nelson. “We expect approvals from two of the Big Three OEMs for the first commercial applications sometime in the first quarter of ’03.”

DuPont Automotive unveiled its “Catalyst” interior and exterior design program in conjunction with the International Auto Show held this January in Detroit. Intended to be a “vehicle for future thinking”, as well as show the importance of color in branding vehilces, Catalyst integrates 96 custom interior and exterior design elements with advanced materials and finishes into six proposals for concept vehicles. The styles of the concepts are designed to reflect current trends in the market and demonstrate how they may develop in the future.

General Motors selected two grades of Bayer engineering resins to enhance the aesthetics and safety of the Pontiac Aztek instrument panel. Described as the industry’s first ever Sport Recreation Vehicle, the Aztek is pegged as a cross between a SUV, minivan and sports sedan.

GM selected Lustran Elite HH (high-heat) ABS 1827 to shape the instrument panel cluster, radio trim plate, end caps and forward extension defroster grill of the Aztek. This grade of Lustran was chosen for its high-heat resistance, dimensional stability and its ease of coloring with metallic flake colorants. GM designers decided to use metallic flake colorants to the IP to enhance the vehicle’s distinctive appearance.

Bayer’s Bayblend T 85, a general purpose PC/ABS blend, was chosen for the Aztek’s driver-side knee bolster and glove box assembly. The Bayblend resin’s superior impact strength eliminated the need for metal reinforcement behind the knee bolster, which is composed of two separately molded pieces. The two pieces are each 9 in. by 20 in. by 2in. and feature molded-in ribs to improve structural integrity. Bayer supplied the molder, Meridian Automotive Systems (Dearborn, MI), with a variety of technical support services, including Finite Element Analysis and aid with the design of mold cooling.

The changing face of resin distribution

The resin distribution business in Canada is being reshaped as a result of recent business decisions and the entry of new players employing non-traditional strategies for moving materials.

ResinDirect LLC, a subsidiary of Louis Dreyfus Energy Services, opened a sales office in Davidson, NC last year and has assigned two sales representatives to service Canada out of this office. Additionally, the company is leveraging an exclusive sales alliance agreement with GEPolymerland to expand its coverage of the LTL and bulk prime commodity resin market in Canada. The company distributes for BP Amoco, Nova, Formosa, Equistar and Huntsman, among others.

“We see ourselves as the next generation of distributors,” says ResinDirect president, Bill Rippe. “We bring aspects to the resin distribution business that traditional family shops lack.”

Originally evolving as an offshoot of its parent company’s energy and risk management businesses under the name of Louis Dreyfus Polymers, ResinDirect still offers customers risk management services. For buyers of resin, this usually takes the form of long-term contracts designed to limit or remove pricing fluctuations. The company sells resin either directly, through its own sales offices, or through its arrangement with GEPolymerland. ResinDirect owns and manages the resin inventory, including setting of prices, while GEPolymerland acts as the sales agent, handling packing, shipping and delivery through 20 North American warehouses, including four in Canada.

Channel Polymers entered the Canadian market in September of last year. Channel is a wholly-owned division of H. Muehlstein & Company, and is the main arm of the parent company’s LTL specialty and prime polymers business. Worldwide, Channel’s sales grew by 29% in 2002. The company has added several new Canadian customers since entering this market, according to Andrew Spicer, senior sal
es specialist for Canada.

“Coming into Canada, we didn’t want to be just a ‘me too’ company,” says Spicer. “We bring a different portfolio of products, not just shared lines.”

The company’s product line includes resin made by Sunoco, Samsung, Kepitel and Solutia, the world’s second largest producer of nylon 6/6. Channel also sells Muehlstein’s line of compounded products, such as filled PP and PE.

Albis Plastics closed its Pickering, ON compounding facility late last year, relocating the plant’s business to the company’s operation in Rosenberg, TX. The shutdown of the Pickering facility, as well as the closing of the Albis Canadian customer service office, has caused speculation about the company’s future in Canada.

“There have been lots of rumors but basically we’re open for business and planning to operate and expand out business in Canada,” reports Michel Vinette, regional sales manager for Canada. Vinette says Albis still has six sales and service representatives in Canada — four in Ontario and two in Quebec. Additionally, it has the use of two warehouse facilities in Canada.

Vinette says the shutdown of the Pickering plant was a strategic business decision made by the company to address manufacturing over-capacity of its product lines, primarily grades of engineering resins for injection molders.

“If it comes down to price, and the price is the same, the sale is made on your relationship with the customer,” says Vinette. “Relationships are still important in this business, and that’s always been one of our strengths.”

Spicer says pricing has been such a driver of sales that distribution companies have to look at new ways of doing business in order to survive. “I think there will be more restructuring in this business. The larger companies have been losing market share over the last few years. Something’s got to give.”

New resins can take the heat

One major barrier to expanding the use of thermoplastics in certain automotive exterior applications has been the high heat used in the traditional automotive paint process. Several new applications illustrate how continuing advances in resin chemistry are allowing high-heat resistant thermoplastics to break through this barrier.

Ford Motor Company and supplier Venture Industries recently produced Ford’s first thermoplastic grill opening reinforcement (GOR) that can withstand the heat of the e-coating curing process. The GOR is made of DuPont’s Rynite PET resin, which was chosen for its strength and high-heat dimensional stability. The new one-piece GOR, which debuts on the redesigned 2003 Lincoln Navigator and Ford Expedition, weighs significantly less than the thermoset SMC component it replaced.

Bayer’s Triax DP 3155, a blend of ABS copolymers and polyamide, was developed to withstand the high temperature (up to 185C) of the automotive paint process. The resin is now fully commercial and is being targeted at body panel and fender applications.

Dow Plastics has introduced a new high-heat, high-impact, blow-molding grade of ABS for spoiler applications. Magnum 1250 BG is able to withstand high-heat painting processes typically used for spoilers.

“One resin frequently used in spoiler applications produces a part with a lot of flash and requires significant post-molding work before painting,” says Jim Otis, Dow global product manager, PC/ABS. “Our material needs less post-molding work and, as well, is 6% lighter than polycarbonate-based material.”

The material’s first commercial application is the spoiler on the Pontiac Grand Prix.