With medical manufacturers looking for new materials that provide better patient safety, GE Plastics has introduced a line of thermoplastic material it believes can replace lead in many applications that require radiation shielding.
The material, LNP Thermocomp HSG, addresses a pressing concern because of the European Union's Restriction of Hazardous Substance directive, which calls for the elimination of lead in most electrical and electronic equipment.
It also reduces system costs and gives designers more freedom to shape X-ray equipment to obtain better performance, according to Clare Frissora, market director for health care at GE Plastics in Pittsfield, Mass.
Because the new compound can be injection molded, it also allows for more precise control over the radiation that filters through, and can enhance the targeting done by the X-ray equipment, Frissora said.
``The performance is the key,'' she said. ``It is environmentally responsible.''
In addition, secondary operations are eliminated with injection molding, so the total cost of manufacturing can be reduced, Frissora said. Lead needs to be machined and stamped, and secondary operations are needed to include other pieces in the component.
The shielding material in X-ray equipment is used in a collimator, which absorbs stray radiation and limits the X-ray exposure dose. GE said potential applications include X-ray shielding devices and containers, housings, X-ray tubing components, dental X-ray equipment and nuclear medicine containers.
The resin's compounds are based on tungsten, a nonhazardous, high-specific-gravity material in nylon 6. Tests by GE, using the company's OEC-9800 X-ray machine, found LNP Thermocomp HSG can shield radiation up to the effectiveness of lead without leakage or hot spots, the company said.
Working with Thogus Products Co. in Avon Lake, Ohio, GE Plastics is creating new grades of Thermocomp HSG, including an elastomeric grade with high elongation for greater design flexibility.
GE Plastics introduced the material at the Medical Design & Manufacturing East trade show, held June 12-14 in New York. The company also announced it added in-house coinjection blow molding capabilities to its polymer processing development center, which it is using to develop applications for its Lexan HP polycarbonate resins in container, bottle and vial applications.
Owens-Illinois HealthCare Packaging Inc. has used Lexan HP in multilayer products since 2001, Frissora said. Now GE Plastics is looking to show other companies how to use Lexan HP for diagnostic vials, culture vials and drug containers.
``If we can help improve the ability to process Lexan HP, we can shape the solutions and the shapes of the bottles,'' Frissora said.
She said Owens-Illinois demonstrated it is possible to circulate the flow of material in different amounts around the length, the circumference and the gate closure so the container has a thin neck and shoulder, long body and thicker gate closure.
``We want to give the health-packaging industry a wider set of options when they are trying to protect blood tissues or pharmaceuticals so the samples are not contaminated. Sandwiching the barrier materials with exterior layers of Lexan allows people to address a wider set of needs when looking at their packaging options,'' she said.
That issue is of growing importance to health-care companies as the industry shifts away from aseptic package filling to terminal sterilization - a process in which companies take an empty bottle, fill it, seal it and then sterilize at the end of the filling process.
``Regulatory agencies are starting to move to terminal sterilization,'' she said. ``It gets around the breakage issue and can get rid of the haze'' associated with aseptic packaging.