PC suppliers target medical market with new grades

The world''s two leading suppliers of polycarbonate (PC), Bayer MaterialScience and GE Advanced Materials (GEAM), made public market introduction of new grades for the medical market in mid-May.

At Bayer, new PC film Makrofol LP 209 is designed not to yellow after repeated use of gamma radiation and electron beams to sterilize equipment, single-use articles, and instruments. Bayer says an additive package keeps the film transparent. Applications are expected in titration plates, instrument boxes, and packaging for implants, among others.

The film satisfies the requirements of international standard ISO 10993-1 relating to the biocompatibility of plastics that are in contact with body fluids and tissue for up to 30 days. The polycarbonate also meets the criteria of American standard US-Pharmacopoeia, Class VI, relating to biological compatibility. Standard thickness is 175 to 500 µm; it''s available with top and bottom glossy; other thicknesses and surface structures can be manufactured on request.

Competing supplier GEAM commercialized three new grades of its Lexan PC: Lexan HPX8R, HPX4, and HP1HF. The first two constitute a new product family: PCs that lack additives but still offer flow performance better than standard PC grades. GEAM reckons the combination of an additive-free material with good flow will attract molders and OEMs from the health-care market who need to improve cycle times and mold-filling performance but face concerns about additives leaching, or the loss of surface additives during cleaning.

These two grades (HPX8R and HPX4) use an unidentified copolymer formulation to realize the improved flow without additives. This copolymer also gives the materials self-lubricating properties. Both are autoclave sterilizable.

HPX 4 is particularly suitable for repeated washing and cleaning, according to the supplier. Predicted applications are in surgical instruments, personal drug delivery systems, and monitoring equipment.

HP1HF is for use in similar applications as well as for fluid recovery components. It meets biocompatibility and FDA food-contact requirements, and processes well with flow of 37 MFI (g/10 min). Bayer MaterialScience, Leverkusen, Germany; www.makrofol.com. GE Advanced Materials, Bergen op Zoom, Netherlands; www.geadvancedmaterials.com

NanofillersNanofiller fights microbes

Silver''s capacity to ward off organisms has been known since antiquity when ancient Greeks and Romans stored perishable liquids in silver containers to avoid spoilage. Its present day anti-microbial application has been limited due to obvious cost problems, but a company is now offering a price-competitive nanofiller for a range of polymers and processes that requires loadings of 1% or less, dramatically changing the cost structure. NanoHorizons (State College, PA) has polymer-compatible gold and silver nanoparticles for research and pilot-production volumes priced from $100 to $400/liter, which it says is 90% below the cost of the nearest competitor.

"The novelty we bring is tailored nanoparticles that are low cost," explains Dan Hayes, NanoHorizons director of operations. "We design a nanoparticle system specifically for your polymer and application."

To date, the company has successfully paired gold and silver nanoparticles, which measure from 10 to 90 nanometers, with polyethylene, polyurethane, and polyester as well as a variety of processes. "We haven''t changed the viscosity significantly in the concentrations we''re looking at," Hayes says, "so it is absolutely compatible with the present processes."

Although the nanoparticles aren''t currently in any commercial applications, Hayes expects launches in 2006. He couldn''t comment specifically for reasons of confidentiality, but Hayes said potential applications areas include medical devices, footwear, clothing, and food packaging. NanoHorizons Inc., State College, PA, USA; www.nanohorizons.com

AdditivesMultipurpose antiblocker improves film quality

A multifunctional antiblock additive is said to increase blocking efficiency by 47% in thin-gauge polyolefin films compared to standard materials. It also reduces both haze and the coefficient of friction by up to 40%. This product, 102765, reduces the need for antiblock and slip addition in most applications. It combines mineral and organic antiblocking agents and is more efficient at lowering blocking force than either one is alone, says the manufacturer.

The organic antiblock component involves a chemical species optimized for use with the diatomaceous earth to which it is mated. Tests have shown no negative affect on sealability. It is also less abrasive than standard antiblocks and reduces potential gel formation.

Ampacet Corp., Tarrytown, NY, USA.; www.ampacet.com

FillerHigh-performance concentrate ensures competitive end-product price

A new range of Pryltex has been developed with up to 65% glass-fiber content. The manufacturer claims this makes it one of the highest glass-fiber-content products on the market, which helps assure a competitive price for end products. Through dilution with PP, it can represent a major technological and economic benefit for injection molders by affording resin savings. The company believes this dilution technique is more profitable to molders than direct compounding of glass fibers. The two-step process (impregnation and coating) enables the integration of additives within Pryltex during coating. The range consists of two fiber lengths (12 and 25 mm) and is available in natural, black, and colored grades. Arkema, Paris La Défènse Cedex, France; www.arkemagroup.com