DÜSSELDORF, GERMANY (Dec. 3, 9:05 a.m. EST) — German replicator OK Media Disc Service GmbH & Co. KG is replacing polycarbonate with polymethyl methacrylate resin in commercial-scale production of digital versatile discs, and its first such DVDs hit the market in Europe in October.
Stefan Klahn, OK Media's production manager, cited PMMA's improved scratch resistance and lower resin cost as factors helping to drive the change.
Acrylic materials supplier RÃ¶hm GmbH & Co. KG of Darmstadt, Germany, was touting its PMMA resins for use in a broad range of new applications at the booth of parent company Degussa AG at K 2001 in Dusseldorf. In an interview there, RÃ¶hm spokesman Jurgen Jourdan acknowledged that many firms have been investigating PMMA as DVD base material for some time, but termed OK Media's decision a “breakthrough.”
Klahn, in a Nov. 20 telephone interview, said his firm can produce 20,000 DVDs per day at its headquarters plant in Nortorf, in the north of Germany, and plans to boost that capacity by 50 percent next year. It also can produce 200,000 compact discs a day, and considers itself to be one of Europe's 10 largest disc replicators. The 200-employee OK Media currently is running two DVD production shifts and making about 60 percent of the discs out of PMMA resin.
“By mid-next year, we expect to switch over [entirely to PMMA],” he said.
While there was DVD overcapacity in the first half of 2001, “production is overloaded today,” Klahn said, noting that Christmas provides a strong seasonal surge in demand. Still, the 15-year optical-media veteran believes market acceptance of DVDs is growing quickly and will remain strong.
OK Media began working closely with RÃ¶hm on the project in March, and the two began operating a DVD pilot plant for customers in May, running RÃ¶hm's Plexiglas DQ501 molding compound. OK Media is using that grade to make DVD-5, DVD-9 and DVD-10 formats.
Klahn said that PMMA can be processed with a barrel temperature 40°-50° Celsius (104°-122° F) lower than with polycarbonate; costs 10-15 percent less; offers low birefringence; and can eliminate the need for pre-drying the resin. He said the acrylic's improved scratch resistance is both an aesthetic and performance plus, especially for rental DVDs that quickly can become marred. Additionally, most scratches in PMMA discs can be fixed with repolishing, which is not possible with polycarbonate.
OK Media still pre-dries its PMMA resin, “just to be cautious,” Klahn said. But he noted that it may not be necessary, and that eliminating that step would save replicators money on resin-drying equipment and in energy costs.
The biggest disadvantage in using PMMA, according to Klahn, is his company's shop-floor inexperience in running the material.
“We have 15 years of experience with polycarbonate,” he said. Though laser discs were made from PMMA many years ago, those products never caught on with consumers. “We need more process experience, over time, to optimize [PMMA disc production],” Klahn said. “The aim now is optimize our yield.”
DVD production cycle times are running a tad slower with PMMA right now than with PC, but he fully expects to be able to eliminate that gap with continued fine-tuning.
And Klahn believes RÃ¶hm is close to being able to sell its materials to other replicators.
He said PMMA might have potential use for 8-millimeter compact discs as well, but he said that there are warpage problems with using the material in 12mm CDs. For now, though, OK Media is concentrating solely on using PMMA in DVDs.
Due to a complicated heritage, RÃ¶hm retains the Plexiglas brand name in Europe, Africa, Australia and Oceania, but those products are distributed in the Americas under the Acrylite brand by Cyro Industries, a Cytec Industries Inc./ RÃ¶hm joint venture in Rockaway, N.J.