HOUSTON — While a slew of competing materials have flexible PVC in their sights, the well-established material may prove to be a moving target that won't go down easily — if at all.
The hunters and the hunted gathered June 24-26 to talk things over at Flexpo '98, an industry conference hosted by Chemical Market Resources Inc. of Houston.
The attraction in replacing flexible PVC lies in the 6.7 billion-pound annual market that flexible PVC compounds hold in North America alone. This output covers markets such as medical bags and tubing, floor coverings, shower curtains, toys, upholstery and automotive trim. CMR President Balaji Singh pointed out that a mere 1.5 percent of this market could justify opening a full-scale polyolefin or elastomer plant.
Flexible PVC is vulnerable because of a lack of new technology, advances in competing materials, such as polyolefins and thermoplastic elastomers, and environmental issues, Singh said.
The PVC replacement bandwagon has led to offerings from several challengers. This group includes:
The Cryovac division of Sealed Air Corp., the Duncan, S.C., firm that ranked second in Plastics News' 1997 survey of North American film and sheet manufacturers.
Dan Wilburn, senior product development engineer, said Cryovac has phased out PVC shrink film in paper products and PVC stretch film for poultry packaging, replacing them with multilayer films combining linear low density polyethylene and ethylene vinyl acetate.
In paper products, the LLDPE/ EVA film offered 80 percent maximum shrinkage, compared with 50 percent for PVC film, Wilburn said. The poultry wrap had better tear resistance and showed superior sealing ability.
``No one wants to pick up a chicken package in the supermarket and have it be wet on the bottom,'' Wilburn said.
Dow Chemical Co., which is aiming metallocene PE at medical bags, a market dominated by PVC.
In testing at Dow's research labs in Midland, Mich., metallocene PE film bags fared better in drop tests and offered 30 percent lower density than PVC bags, Dow films development leader Bruce Lipsitt said.
The lower density allows for downgauging, which can balance out metallocene PE's higher cost, Lipsitt said.
Solvay Engineered Polymers, a Grand Prairie, Texas, firm has developed polypropylene-based flexible polyolefins aimed at displacing PVC in auto body side moldings. In 1996, PVC held a 40-47 percent lead over flexible polyolefins in that application. Dennis Slatton, Solvay product development engineer, said new advances in Solvay's Sequel-brand products could give flexible polyolefins a 40-45 percent advantage by 2006.
Slatton said Sequel products provide excellent dimensional stability and cost savings of as much as 10 percent over PVC.
Other firms, such as film processor Huntsman Packaging Corp. of Salt Lake City and Chicago product developer Herbst Lazar Bell Inc., confirmed that potential PVC replacements are out there, but they've had a tough time pushing PVC aside because of its low cost and steady performance.
Huntsman, which ranked eighth in Plastics News' ranking of North American film and sheet manufacturers, holds either the No. 1 or No. 2 spot in North America in many film categories, including second-place status in PVC film, according to Jack Knott, executive vice president and chief operating officer.
The 250 million-pound annual market for PVC film, including fresh meat, cheese and produce wrap, is shrinking by about 1 percent a year because of changes in packaging configurations, not because of shortcomings in the material, Knott said.
This scenario played itself out recently when Huntsman tested its own Omni-brand PVC film against its Omni Plus polyolefin film and a coextruded polyolefin film made by a European firm. The PVC film more than held its own in performance and cost.
``PVC film still provides the best balance of properties necessary for the current end use,'' Knott said. ``And consumers are not going to walk into a supermarket to buy a package of ground beef and say they'll pay more if it's wrapped in a non-PVC film.''
Len Czuba, medical sector director for Herbst Lazar Bell, said materials such as polyester, EVA, polyolefin blends, polyolefin laminates and functionalized polyolefins could expand product opportunities, but probably will not be able to take much of PVC's 95 percent market share in medical bags.
Each of these materials has weaknesses that have kept PVC on top so far, said Czuba, who urged processors not to make ``emotion-driven decisions'' based on unproven claims against PVC.
Also, competition apparently will increase slowly — polyester was being developed as a PVC replacement when Czuba entered the industry in the mid-1970s.
The role of PVC champion at Flexpo ultimately fell to Robert Brookman, PVC business manager for Teknor Apex Co., a top 10 North American PVC compounder based in Pawtucket, R.I. Brookman spoke on behalf of the Vinyl Institute.
Before explaining PVC's benefits, Brookman took an indirect swipe at PVC's competitors by saying comparisons are difficult because so many proposed replacements are ``still in the evolutionary state.''
``It's a bit like dueling with a shadow,'' Brookman said. ``Without a technical definition of the [competing] polymer and with only speculative economic data, it's extremely difficult to develop an understanding of replacement potential.''
Flexible PVC's advantages include its availability in numerous forms and its ability to be compounded, welded, pigmented, embossed and printed, Brookman said. The product's clarity, weatherability, flame retardancy and electrical properties also are difficult for other materials to match, he added.
Cost remains a major consideration. Brookman pointed out that some compounded PVC still costs only 45 cents a pound. That amount is less than the base costs of some polyolefins and substantially less than that of more-engineered materials.
Brookman also remembered the customer at a conference that was long on technology.
```Polymers of choice' is a decision that will be made in the competitive marketplace — not here and not by us,'' he said.