The roll-out over the last three years of Technylstar, a radically different type of nylon 6 from French nylons specialist Rhodia, as well as its more recent nylon/ABS alloys made using new compatibilizer technology, show that there is still plenty of room for development in these warhorse engineering thermoplastics. Speaking at Maack Business Services' Polyamide 2003 conference in Zurich in June, Paris-based Automotive, Electronics & Fibers Div. president Andre Blazquez said that nylon 66 grades of Technylstar are now in advanced development. Speakers from several other suppliers at the event confirmed that the potential for innovation in nylon polymers and compounds is nowhere near exhausted.

Technylstar nylons have a starlike, highly branched structure. There are now more than 15 applications running in various injection molding grades. The nylon 66 grades, likely to debut next year, will have high viscosities suitable for extrusion. Rhodia's original expectations for the nylon 6 grades were that they too would have high viscosity, but they turned out to flow even faster than linear nylon 6. This, together with their enhanced ability to wet glass fibers, means they can take higher loadings than regular grades. In the meantime, said Blazquez, researchers have learned much more about how to control properties of the polymers.

Technylstar is the result of innovation in polymerization and compounding, but Blazquez demonstrated that innovation in the nylons business stretches upstream as well as down. Particularly interesting for delegates at the conference, many of them from the nylons supply side, were clues he gave of new routes to nylon feedstocks adipic acid and caprolactam that should yield significant cost reductions for suppliers. He said that Rhodia's new Capucine process for making caprolactam from adiponitrile, now ready to be industrialized, is 30 percent more competitive than technology used today, while technology that takes conversion of benzene into adipic acid from three stages to two cuts costs by 25 percent and reduces some effluents by 95 percent. Neither technology is likely to be used commercially before 2008, though.

Tilman Krauch, nylon intermediates VP for BASF (Ludwigshafen, Germany) said nylons suppliers will have to look more to applications at the beginning of their lifecycles if they want to sustain their margins. Three that he highlighted are all in the automotive electronics area: componentry for 42V applications, molded interconnect devices (MIDs) and closely related "mechatronic" parts that combine electronic and mechanical functions. Use of nylons in automotive applications is set to continue to grow at 6 percent annually until at least 2010, Krauch said. He noted that by then, consumption of nylons in Asia will have overtaken that of the NAFTA region.

Indeed, auto production in China will more than triple between now and 2020, said Akio Koma, general manager of Ube Industries' Engineering Plastics Business Unit in Tokyo. Passenger-car production alone will rise from the current 1.4 million units annually to 9 million. Growth in nylons consumption for automotive applications is projected at 20 to 30 percent annually, even higher than the growth in automotive production itself. That's because OEMs in the region are quickly moving to make vehicles with the same level of technology as in Japan and the West. Koma said that while today's vehicles contain on average 2.8 kg of nylon 6, the figure will rise to 4.2 kg in 2010. Across non-automotive applications, average growth is expected to be 7.5 percent annually, driven by such factors as the growth of transplant operations for appliances and communications equipment, the need for more industrial equipment, and the general rise of living standards in China.

Specialties are key

Emphasis on specialty nylons and applications was clear in several presentations. Degussa (Darmstadt, Germany) highlighted the potential for nylon 12 in sheathing around acrylic optical fibers to reduce the weight of the harness in a luxury car from around 80 kg to less than 65 kg, for example, while transparent amorphous nylons in the Grilamid TR range from EMS-Grivory (Domat/Ems, Switzerland) are aimed at high-end applications beyond the reach of more common, clear thermoplastics like polycarbonate and acrylics.

Judging from a presentation by its technical manager Shigeru Okita, innovation at Toray Industries Inc. (Nagoya, Japan) is running at a high level, with developments in novel nanocomposites and alloys. Applications should debut soon. New compounding technology for nanocomposites allows higher levels of fillers than can be achieved with production of the composites in the reactor, which is the more common route among polymer producers. It also enables simultaneous addition of other additives.

Okita cited two hybrid nanocomposites. ND15 contains a homogeneous dispersion of nanofillers and mineral fillers. It has similar density to a 15 percent glass-reinforced grade, but is around 20 percent stiffer. In addition, shrinkage is lower and more isotropic.

Nanocomposites tend to have poor impact strength. But grade KT-01 contains nanofillers and an impact modifier to overcome the disadvantage. And it has a lower coefficient of linear thermal expansion (CLTE) than conventional impact modified nylons.

Alloying nylons with polyolefins reduces water absorption, but negatively affects rigidity. Toray is developing "phase inversion" alloys to overcome this problem. Here, although nylon 6 is the major component, polypropylene is the continuous phase. The properties of the continuous phase dominate so that under .46 MPa load, deflection temperature is 145C, vs. 166C for a conventional alloy. Because of the high level (around 70 percent) of nylon, however, the effect is mitigated; flexural modulus falls from 2.34 to 1.21 GPa after conditioning, compared with a decrease from 2.27 to .85 GPa.

Atofina (Paris), which has had Orgalloy nylon/polyolefin alloys available for several years, is aiming squarely at extrusion blowmolded automotive air ducting with its latest flexible LT grades, which span 200 to 600 MPa modulus. Development manager Christophe Maldeme said that sequential blowmolding with flexible and rigid grades can cut the number of individual parts from 20 to three, and the weight from 2.5 to 1 kg. Thermoplastic polyetherester elastomers are generally favored for such parts, but Maldeme said LT grades have better long-term thermal resistance, better stress-strain behavior, and lower creep. Developments on high-temperature nylons for the same application were also discussed by Georgios Topoulos of DuPont's Zytel R&D group in Geneva. Under development are copolymers of nylon 6T and XT.

Prospects for films

Several delegates highlighted the potential for nylons in film packaging applications. BASF's Krauch said that with the rise of 99-cent shopping outlets, where everything sells for the same price, packaging becomes a key product differentiator. Similarly, Roberto Ramos, VP with Brazilian petrochemicals giant Braskem (Sao Paulo), said the new government in Brazil, wanting to show its "green" credentials, may be more assiduous than its predecessor in applying legislation that calls for barrier films, such as those made of nylons, to pack fresh produce in supermarkets.

Ube's Akio Koma noted that growth of nylon packaging films in China should also be strong, owing to the vast distances for transporting produce, a massive population, and increasing living standards-hence the need for products with longer shelf lives and the increasing demand for preprocessed foods. Growth in biaxially oriented nylon (BOPA) films is running around 15 percent annually for such applications as noodle soup pouches and resealable bags of vegetables and seafood. Local demand currently stands at around 10,000 tonnes annually, two-thirds of which is supplied by imports. But new projects are being studied by local producers of oriented polypropylene (BOPP). Growth in coextruded nylon films is also running at a similar pace for such applications as meats and rice cakes, although consumption is currently at about 4000 tonnes each year.

Peter Mapleston [email protected]