Just as the medical market has enticed processors in other sectors of the industry with the allure of “recession-proof” demand, high-barrier film developments are increasingly targeting pharmaceutical, nutraceutical, and device packaging.
Overall U.S. plastic-film demand is projected to grow 2.8% annually into a 17-billion-lb, $14 billion market by 2012, according to The Freedonia Group, which forecasts even stronger growth – 6.1% – for sterile medical packaging through 2012. Plastics is the fastest growing material in volume and demand for the $4.8 billion market, which, in addition to things like thermoformed trays and injection molded syringes, includes film products like pouches and sterilization wraps. The emphasis was apparent at last November’s Pack Expo, where a number of film developers rolled out new lines aimed at medical.
PCTFE- and PVdC-powered barrier
Targeting the extremely high oxygen- and moisture-barrier requirements of pharmaceutical and nutraceutical blister-packaging applications, Klöckner Pentaplast extended its line of Pentaphram ACLAR structures at Pack Expo, saying the latest offerings extend gas-barrier performance. The four-layer PVC/EVOH-PE/ACLAR/PVC film, which sandwiches barrier materials EVOH and ACLAR polychlorotrifluoroethylene (PCTFE) between layers of vinyl, is also designed for good lay flat and machinability on standard form/fill/seal packaging lines.
Above: Rollprint’s solvent-free Triad film promises strong welds with low seal-initiation temperatures, good hot-tack strength, and a glossy silver appearance. Top left: Applying vacuum deposition of aluminum instead of a laminated aluminum layer, ExxonMobil Chemical Films’ Metallyte technology reduces packaging weight while improving barrier and seal.
The company also expanded its line of Pentapharm kpMax films for the most oxygen- and moisture-sensitive products. The four-layer structure here consists of PVC/PVdC/ACLAR/PVC, with polyvinylidene chloride replacing EVOH to combine with and augment the barrier properties of PCTFE.
Sealant-free, FDA compliant
The sealant layer of a new high-barrier overwrap can bond to foil without the use of solvent- or water-based materials, helping satisfy a Food and Drug Administration (FDA) requirement that items like inhalants be delivered in solvent-free packaging. Triad high-barrier solventless overwrap was launched by Rollprint Packaging Products Inc. (Addison, IL) during Pack Expo, and Doug Mapes, Rollprint account manager, told MPW that his company applied its own proprietary metallocene-based sealant chemistry and specialized extrusion-coating line to create the product, which at press time in was in validation, with plans for a commercial launch to follow within the next few months.
Triad is a extrusion-coated lamination of polyester, aluminum foil, and metallocene polyethylene (PE), and Mapes said that in addition to chemistry advances within the material, another key to the product is an extrusion laminator that applies the PE sealant at a thickness of only 0.5 mil with a downstream sealing rate of 100 ft/min.
In a typical overwrap product, each side has 1.5 to 2 mils of sealant, which doubles to 3-4 mils once the package is joined. For Triad, max sealant thickness is only 1 mil, which helps speed sealing since less material needs to be heated.
Greater barrier, seal: less material
ExxonMobil Chemical’s film business also touted barrier properties and seal strength at Pack Expo, with its line of Metallyte multilayer biaxially oriented polypropylene (BOPP) films, which use vacuum deposition to add aluminum, instead of a laminated aluminum foil. Christian Candoni, global marketing communications manager of the company’s films unit, told MPW that, by using vacuum deposition, it’s able to cut weight by 30-50% and offer stronger barrier, with the proprietary vacuum deposition process resulting in aluminum that doesn’t break down when the package is crinkled. The company says that its new Enhanced Sealant (ES) technology, which targets flat-seal formats like pouches, offers seal strengths approaching extrusion-coated polyolefin sealants and thinner cast or blown polyolefin sealant films. It is also lap-seal capable with most OPP films.
Officially launched at Interpack in April 2008, ExxonMobil Chemical now offers three high-barrier BOPP products within the range: Metallyte UHB 18MM882 – constructed with a PE compatible heat-seal layer, vacuum-deposited aluminum, and a transparent PP core; Metallyte UBH 18MM883 – consisting of vacuum-deposited aluminum, a transparent PP core, a non-sealable layer, and a treated surface; and Metallyte UHB 28UBW-ES, which has vacuum-deposited aluminum, a white opaque PP core, and an enhanced heat-sealable layer.
In addition to strong barrier for all, the company says 18MM883 offers convertibility on both sides and good puncture resistance. The 18MM882 product can be converted on the metal side, with lap sealability to PE, and a stable coefficient of friction on the unmetallized surface. The 28UBW-ES is said to provide excellent flex-crack resistance, hot tack, and aroma and flavor barrier. From a sustainability standpoint, Candoni said a life-cycle inventory test showed that in addition to weight reductions, solid waste is reduced by 93%, with metallization of aluminum allowing less to be used.
Outside Pack Expo, a superhigh-gas-barrier film launched that reportedly enables the production of flexible roll-to-roll plastic electronics and reliable protection for medical products. Key to serving these markets is the film’s water-vapor transmission rate of only 10-4 g/m2/day. The new X-Barrier product from Mitsubishi Plastics Inc. (MPI; Tokyo), builds off that company’s Techbarrier technology, which has seen use since 1991 for applications within food, medical, pharmaceutical, and industrial packaging.
Transparent and metal-free, the silicon dioxide (SiO2) vacuum-coated plastic film also blocks out gases like hydrogen, oxygen, and carbon dioxide, with the barrier properties reportedly maintaining high performance in the long-term presence of high temperature and humidity.
Mitsubishi anticipates potential X-Barrier markets in high-performance medical, pharmaceutical, and industrial packages, especially for products like catheters, surgical sutures, contact lenses, tablets, capsules, liquid prenatal nutrition, and dialysis treatments – all items that require oxygen- and high water-vapor barrier.
Other potential applications and markets include packing material for humidity-sensitive products like resin, amino acids, chemicals, semiconductors components, flat-panel displays, and building materials, as well as working as an encapsulation material for electronic devices.—[email protected]