Feature: Pressure on seals accelerates materials R&D

Growing demand for high performance seals is driving investment both in new production facilities and R&D to enable these often critical elastomeric components to meet the ever-increasing demands of the global automotive industry – and its regulators.

Typical of recent reports on this market is one from Markets and Markets, which forecasts the global automotive gasket and seal market to grow from around $8,878 million (E7,778m) in 2015 to reach $12,362 million by 2020 – a compound annual growth rate (CAGR) of 6.9 percent.

An even higher CAGR – 7.1 percent – is forecast for the Asia-Pacific region, led by China, India and other developing countries. Demand for improved mechanical strength and sealing capabilities is expected to drive up sales of high-performance and functional products in this region.

Even in the mature European automotive gasket and seal market, the CAGR is projected to run at 6.4 percent to 2020. This, in part, reflects the region’s position as a major hub for high-end automotive OEMs.

Demand in North America, meanwhile, is projected to grow at a CAGR of 7.3 percent to 2020. Furthermore, many OEMs are planning to set up vehicle production plants in Mexico and Canada, which in turn will drive demand for automotive gasket and seal market in the region.

Amid these regional growth patterns, vehicle makers are requesting increasingly high-strength gaskets and seals able to endure high heat and pressure, while also reducing weight.

Regulation underpins most of these technology shifts, as with the EU move to reduce CO2 emissions from vehicles from 140 g/km in 2012 to 90 g/km by 2020. This is prompting automotive OEs to pull for more lightweight and sustainable parts and materials, as well as more efficient engines.

Consumer trends also have a significant impact, as seen, for example, with the current move to turbocharged engines: the proportion of turbocharged petrol-engines in use is expected to rise from 11 percent in 2012 to 31 percent in 2020. (See chart below).

These turbo engines employ excess gas recirculation (EGR) systems that bring aggressive gases in contact with sealing and containment parts. This is creating a need for new range elastomers such as DuPont’s VMX-5000 pre-compound (see p25 of DKT Preview) with greater long-term chemical and resistance than previously available.

Bio-polymer

Sustainability is another driver in the automotive seals sector, as evidenced by Freudenberg-NOK Sealing Technologies development of an EPDM rubber compound from a polymer produced from sugarcane-based feedstock. The development, it said, responds to the emergence of increasingly stringent emissions standards and the push for sustainability.

The bio-polymer is produced via a process in which a sugarcane-produced ethanol is converted into the ethylene that forms a substantial portion of the base polymer. The sugarcane base allows the material to be 45-percent bio-renewable.

“We had been working with polymer suppliers for ways to reduce our carbon footprint but [their] offerings lacked the specific characteristics we needed for our advanced manufacturing processes,” said Joe Walker, global director, advanced materials development at Freudenberg-NOK.

The Plymouth, Michigan-based company has focused much of its next-generation manufacturing technology on a single cavity, net shape injection moulding process. This, it said, has resulted in reduced waste and energy demand and overall improved manufacturing control, yielding improved quality.

“So we initiated a project to research the area, and were able to develop a material that can be used in our next-generation injection moulding process,” Walker concluded.

Increasing technical demands on automotive seals can be seen in SKF Sealing Solutions GmbH’s materials selections of ethylene vinyl acetate (EVM) rubber, from Lanxess, for the patented design of the cylinder head cover for a number of Volkswagen diesel models – including the 10-cylinder diesel version of the high-end Phaeton model and the Touareg SUV.

The aluminium cylinder head cover protects the valve gear, fuel injection system and cooling lines from moisture and dirt from outside while at the same time protecting the environment from escaping lubricants and vapours.

The cover must therefore be hermetically sealed, and at the same time the rubber seal must be resistant to the high engine temperatures and to oil and other aggressive fluids. Finally, the Levapren EVM-based seal must retain its integrity for the lifetime of the engine.

According to Lanxess, its ethylene-vinyl acetate rubber offers all these properties: it does not swell in oil, is resistant to coolants and combines well with fillers. It is also said to withstand continuous temperatures of over 170°C – and transient peaks of over 200°C – and to remain flexible even at temperatures below freezing.

Weight-reduction was the target for Teknor Apex when it launched a series of thermoplastic elastomer (TPE) compounds for window encapsulation and other injection moulded automotive sealing applications earlier this year.

Based on styrene block copolymer (TPE-S) chemistry, they are also said to exhibit 50 percent higher flow than the highest-flow TPV in the Sarlink range. Compared to other TPE-S materials, these compounds are claimed to provide an enhanced surface appearance, improved tensile properties, better UV resistance, and greater stability upon heat aging.

Teknor Apex recommends these TPEs for window encapsulation and other automotive seals requiring precise or intricate over-moulding onto rigid substrates. The company can manufacture the compounds at its facilities in the US, Europe, and Singapore.

Road to China

In line with the above reported regional growth trends, Federal-Mogul’s Powertrain Division has announced plans to build a new sealing and gasket manufacturing facility in Nanchang, China. A spokeswoman said Federal-Mogul is expanding to meet growing demand from Chinese OEMs to meet more stringent environmental regulations.

The facility will produce multi-layered steel cylinder head gaskets, exhaust manifold gaskets of high temperature alloy, heat shields, bonded pistons and the company’s MicroTorq brand of dynamic seals, which are not currently offered in the region.

The 258,000-sq.-ft. plant will double the capacity of the company’s current sealing manufacturing operations in Nanchang. According to the spokeswoman, the new facility will replace the existing one because it will provide a larger footprint and more advanced manufacturing capabilities.

Production is expected to begin in 2016, with employment at the facility expected to grow to more than 500 employees in the next two years, according to Federal Mogul.

“This facility will serve as one of the most advanced sealing manufacturing facilities in the world, while helping Federal-Mogul Powertrain to increase its competitiveness and market share throughout China,” the spokeswoman said.

Federal-Mogul said the sealing business in China has grown at an annual rate significantly higher than the growth rate of engine production in the past five years based on increased demand for vehicles that provide high combustion efficiency and low emissions.