business

PEN: THE NEW POLYESTER The future is bright for polyethylene naphthalate if a few hurdles can be cleared

Paige Marie Morse C&EN Houston

P olyethylene naphthalate (PEN) is poised to enter the competitive plastics market in a big way. Several

major chemical companies have invested heavily in its development and are hoping that a sizable market awaits its arrival. Their ambitious goals include taking on the glass and aluminum markets that each year supply 16 billion bottles for beer and 35 billion cans for soft drinks.

But significant demand for this polyester is far from secure. Although PEN has begun to penetrate small performance-driven mar­kets around the world, larger markets are currently out of reach because of pricing is­sues. Food & Drug Administration regulato­ry status, and recycling concerns.

'Unless there is a large market de­manding PEN, it will not be a business worthy of the eight or 10 companies that are currently competing in it," says James K. Caldwell, Eastman Chemical's business market manager for PEN.

It is critical that the issues hindering large-volume PEN use be resolved in the next few years, or advances in alternative materials will lay claim to its potential markets.

From a performance standpoint, PEN'S future looks bright, with opportu­nities in several markets, including film, fiber, and packaging. Its chemical struc­ture, with a rigid double ring in the poly­mer backbone, explains many of the per­formance enhancements seen when compared with the single-ring structure of the large-volume polyester, polyethyl­ene terephthalate (PET). PEN'S rigidity translates to increased strength, heat sta­bility, and barrier properties compared with other polyesters.

The primary commercial market for PEN now is in specialty films. One com­mercial product is the film used for Ad­vanced Photo System cameras. PEN film is 30% thinner and more curl resistant than conventional 35-mm film, providing sharper negatives that are stored in the

PEN's double-ring structure makes it more rigid than PET

o o H ^ O — C ^ Q ) ) — C—O—CH2—CH2 -OH PET

-O—C

C—O—CH2—CK

PET = polyethylene terephthalate, PEN = polyethylene naphthalate

original film cartridge (C&EN, March 11, 1996, page 32).

PEN is also used in electronic film ap­plications, where its "improved thermal performance, dielectric properties, and outstanding thermal aging properties are very useful," says John M. Carson, market manager for PEN at ICI Polyester. Du-Pont—through its acquisition of ICI's polyester business—will soon own the ICI PEN unit, which includes polymer and film production, and will combine it with its PEN electronic films.

An Asian producer, Teijin Chemical, also markets PEN film and the unproc­essed polymer from its manufacturing base in Japan.

Although there has been a lot of interest in PEN films, especially in Asia, the market represents only a small specialty opportunity. In a recent report on PEN opportuni­ties, market research firm Kline & Co., Fairfield, N.J., estimates the annual U.S. market for PEN film at only 2 million lb. That's expected to grow to 9 million lb in 2000 and to 16 million lb in 2005.

Mary Vaughan, manager of packaging practices at Kline, notes that this market in particu­lar can withstand today's high price of PEN. "In film applica­tions, PEN offers many unique properties that let it compete

with higher priced materials such as polyimides." However, competitive pric­ing is an issue in other markets for PEN.

The price for PEN, at $4.00 to $5.00 per lb, is strongly affected by that of the main raw material, naphthalene dicar-boxylate (NDC). Amoco Chemical is the only commercial manufacturer of NDC, and its single NDC manufacturing site, in Decatur, Ala., reached its design capacity of 60 million lb per year just this summer

after several months ——•————— of delay. Mitsubishi

Gas Chemical oper­ates a 2 million-lb-per-year pilot facility in Japan—a volume that has little impact on the commercial market.

"NDC manufac­ture is very complex from a reaction stand­point," says Joanna Money, Amoco's glo­bal NDC product manager. "However, the main challenges

in starting up the plant were not in the chemistry but in the physical processes, such as separation."

Amoco's production problems have had an impact on the opportunities for PEN, according to Eastman's Caldwell. "There were a lot of programs that were being choreographed in 1993 and 1994 to go to market in mid-1995. When the raw material wasn't there, due to a delay at the Amoco plant, some of those pro­grams ground to a halt."

In contrast, Ed Sisson, Shell Chemi­cal's commercial development manager for PEN, is less concerned about Amo­co's delay, but he acknowledges that

-OH

PEN

The oniy commerciai source of naphthalene dicarboxylate, the key raw material for PEN, is Amoco Chemical's plant in Decatur, Ala.

8 NOVEMBER 10, 1997 C&EN

PEN extends the food packaging uses for polyester Process temperature, °F 250

200

150

100

Polyethylene naphthalate (PEN) « * , _, Vegetables Petfoods M e a t s

J a m Tomato Sports drinks sauces

Polyethylene terephthafate (PET)

Mustards

Peanut butter

Dressings

Liquor , Water

Pickles

Drinks

Mayonnaise

Soft drinks,

Baby food

Ketchup

-

Beer

12-oz carbonated soft drinks Wine

i

500 50 5 Oxygen permeability,3 g per ml_ per atm»day

0.5

a C02 permeability is directly correlated with that of 02 . Source: Shell Chemical

PEN sales have been slower than expect­ed for that reason.

Amoco's problems highlight the dis­comfort of depending on a single source for the monomer. "We have been very pleased this year with Amoco's ability to supply NDC," notes Caldwell. "But the reality is that multiple sources would make our job of selling PEN easier."

Shell's Sisson disputes the concerns about a single NDC source, saying: "Amoco Chemical has demonstrated throughout the years of terephthalic acid production [for PET] that it is responsi­ble in the position it holds and also in the safeguards it puts in to protect its single manufacturing site."

In September, Amoco announced its intent to expand the Decatur plant to be­tween 85 million and 110 million lb per year by 1999. The company also is con­sidering building another facility after 2000, which should help alleviate some supply concerns.

The issue of supply security is particu­larly important for the larger market op­portunities in fiber and packaging. In these markets, PEN must displace less ex­pensive materials by offering processing advantages and some performance im­provements. The market response to these subjective factors is much more difficult to predict than obvious cost advantages.

Several applications in the fiber mar­ket are being explored. Tire cord is the largest opportunity—PEN can replace rayon fibers in high-speed tires. In other industrial uses, such as equipment belts and heavy-duty cables, PEN is being con­sidered as a replacement for steel. Most

of the fiber work, though, is in the early development stage.

The packaging market appears to be the best single opportunity for PEN. The higher glass-transition temperature and reduced gas permeability make PEN a good candidate to displace glass and alu­minum cans for applications not previ­ously available to plastic.

PEN bottles are shatter resistant, light­weight, and can be filled at higher temper­atures—allowing its use in many food con­tainers. PEN's heat stability means it can be used in the returnable/refillable beer bottle market, which requires that the beer be pasteurized in the bottles. The in­creased barrier properties of PEN make it suitable for small—12 oz—beverage con­tainers, where PET cannot yet be used.

Kline's estimates of PEN use in the packaging market show a large depen­dence on polymer price. If the price were $3.25 per lb, the market would only be 1.6 million lb in 2000 and 14 million lb in 2005. If the PEN price were reduced to $2.00 per lb, the volume would approach 5 million lb in 2000 and would rapidly grow to 140 million lb by 2005, assuming the price fell to $1.50 per lb.

A recent report by SRI Consulting, Menlo Park, Calif., on PET includes a more optimistic discussion of PEN op­portunities. If the price were $2.50 per lb, SRI estimates PEN demand in packag­ing at 65 million lb by 2000.

Shell's Sisson is particularly upbeat about PEN's use in the packaging market because this market prefers plastics. "Al­most every conversion from glass to plas­tic or a particular PET has been permanent

and- has resulted in market-share gains for the company that converted first."

Kline's Vaughan agrees that PEN can have a role in the packaging market but cautions, "Even though PEN has several good properties and enhancements over PET, pricing is still too far above what would allow it [to break into] high-volume packaging applications."

One way to address this price issue is to use blends or copolymers of PEN with PET to reduce the unit cost. Several projects are in progress at polymer suppli­ers and bottlers. But a major hurdle re­mains in that only homopolymers of PEN are covered by FDA regulations for food applications. Shell petitioned FDA in early 1995 for regulation on the copolymers and blends, but a response is not expect­ed soon. FDA took eight years to respond to Eastman's petition for PEN homopoly-mer, a less complicated system.

Another issue for PEN, in general, and especially for blends and copolymers, is the concern that naphthalate polymers may adversely affect the PET recycle stream. Separation of these polymers is not easy, and because FDA must consid­er environmental issues in its review, that issue has slowed the regulatory pro­cess for PEN copolymers and blends.

Recycling concerns have also been the primary focus of the Naphthalate Polymer Council, a business unit of the Society of the Plastics Industry. Amoco, Shell, Eastman, ICI, DuPont, and 3M sup­port this group, which coordinates test­ing and research and promotes the use of naphthalate polymers.

In describing the efforts of this coun­cil, Eastman's Caldwell notes, "We are all big PET stakeholders, so we are proceed­ing with great caution because we don't want to do anything that would negative­ly impact PET recycling."

Recycling is big business for the PET market. The American Plastics Council reports that 29% of the 2.2 billion lb of PET resin used for bottles in 1996 was recycled. This translates to more than 600 million lb of recycled PET product that is used for everything from outer­wear insulation to car trunk liners.

And while the PEN issues are being re­solved, work is progressing on new pro­cessing methods for PET that give im­proved performance.

What is also evident is that all major PET producers believe they must partici­pate in PEN. "PEN is the next evolution of polyester technology," says Carson of ICI. And everyone wants to be there, even if the market is not yet ready. -4

NOVEMBER 10, 1997 C&EN 9