Plastic-Cork Makers Bob Up All Over.

A handful of start-ups, most of them dedicated to a single product, are convinced they're giving birth to a major new plastic market--wine corks. Not only is there a worldwide shortage of natural bark corks, but they reportedly fail about 8% of the time, souring both wine and customers. "We're bringing in a technology that is so superior to what was used before that we can dominate a market very quickly," predicts Stuart Yaniger, chief technical officer of Neocork Technologies Inc. in American Canyon, Calif., one of the newest entrants. Wine corks are all it makes. "It's a one trick pony, but it's a damn good trick," says Yaniger.

At least four companies are injection molding and extruding foamed plastic wine corks, filing numerous patents and lawsuits as they contend for position in technology and in the marketplace. Of the four larger U.S. firms in this nascent business, two are processors, one is owned by a maker of injection molding machines, and one belongs to a group of wineries. They're after a potential U.S. market of a billion units, and a global market of 9 billion, annually.

Who rules?

The self-described market leader is Supreme Corq Inc. in Kent, Wash. It was the first to develop and commercialize a plastic cork in this country. It opened up in 1992 and commercialized an injection molded, foamed cork in '93. Supreme Corq won't give out production volumes, but says it supplies about 300 customers. It holds 14 holds 14 patents worldwide and has sued several competitors for allegedly infringing them.

A second injection molded cork was launched last year by Guardian Cork, a division of Hettinga Technologies Inc. in Des Moines, Iowa. Hettinga, which declined to discuss its cork production, primarily makes low-pressure injection molding machines.

A third entrant, Nomacore in Zebulon, N.C., started up in 1996 as a one-product division of Nomaco, a maker of other foamed plastic products. The Nomacorc division commercialized its coextruded, foam-core polyethylene corks last year. They are made on two extrusion lines. Nomacorc holds three patents and is being sued by Supreme Corq.

Neocork also started up in '96, with investment from several California winemakers--Beringer, Clos du Bois, Kendall-Jackson, and Robert Mondavi. It commercialized its coextruded foam corks early this year. Neocork owns the process but has them made by a custom extruder, Rubatex Corp. in Conover, N.C.

Neocork chose extrusion because there were already injection molded corks (and patents) in the market, and there had been some failures with them, says Yaniger. Inserting molded corks into wine bottles can create small surface lines that admit air, he says.

Neocork felt extrusion would maintain tight tolerances (0.0008 in. on the diameter), avoid ovality, and control bubble distribution better than molding. Vacuum calibrators couldn't be used because vacuum elongates the bubbles, Yaniger says. Instead, the firm uses special fixtures with spray tanks up to 500 ft long.

POP' goes the cork

All the new plastic corks are made of materials with low taste and odor and absence of flavor scalping. They are formulated without additives other than colorants. Supreme corq uses a medical-grade compound made in-house out of natural rubber, waxes, and polyolefins. Nomacorc uses PE. And Neocork uses an Affinity metallocene polyolefin plastomer (POP) from Dow Plastics, Midland, Mich. It was developed for very fine bubble formation with nitrogen gas. The outer layer of the coextruded cork is a solid elastomer 8-12 mils thick.