Appliance wiring and cable manufacturers need to be fast on their feet these days. Facing a host of requirements ranging from stringent regulations governing the use of halogens in flame retardants to demands for more product functionality in the same space, manufacturers need materials solutions that can solve multiple problems and adapt to different applications.

A new family of flexible Noryl resins from GE Plastics has been developed to enable thin-wall coatings and insulation for wiring and cable to reduce weight and mass, deliver high performance, and help manufacturers exercise environmental responsibility. In addition, these resins have been listed by Underwriters Laboratories under the UL1581 reference standard, enabling proposed products incorporating flexible Noryl resin grades to significantly reduce testing time.

A number of industry and global trends are driving the need for new appliance wire and cable solutions. Companies that manufacture in Europe and Asia, or export products to those regions, must take into consideration current and impending regulations governing the use of such substances as heavy metals and halogenated additives.

Lead and other heavy metals, as well as certain brominated compounds, have been shown to accumulate in the environment. The European Union’s Restriction of Hazardous Substances directive targets the following substances for electronic and electrical appliances: lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyl (PBB), and polybrominated diphenyl ether (PDBE). It applies to products, components, or sub-assemblies for electrical and electronic equipment placed into the European Union after July 1, 2006. RoHS forms a baseline by which similar restrictions are being developed by other nations.

Several other countries have announced regulations similar to RoHS, most notably China and South Korea. Japan has also introduced regulations requiring the labeling of the six hazardous substances in an array of household items.

The European Waste Electrical and Electronics Equipment directive requires all materials containing bromine to be marked and treated separately at end of life. In order to simplify recovery and recycling at end of life, many OEMs are consolidating materials and limiting choices to polymers that meet the performance requirements of the application without the use of bromines.

The widespread use of traditional polyvinyl chloride for appliance wiring and cable is expected to be significantly impacted by these regulations. Although the RoHS and WEEE directives in Europe currently focus on avoiding brominated flame-retardants and the use of lead (which can be achieved with lead-free PVC), but it is anticipated that restrictions on chlorine will come.

Furthermore, PVCs contain phthalates (plasticizers) that pose environmental and health risks when leached into the atmosphere, and form dioxins during incineration. Wire and cable manufacturers that are looking ahead to additional regulations need a replacement material for PVC that meets the RoHS standard regarding heavy metals and brominated flame retardant additives, and the WEEE standard regarding recyclability — not to mention similar regulations in other geographies.

While the spotlight is on new requirements such as regulatory compliance, the need for high performance remains a constant. Substituting a new environmentally responsible wire-coating material is important, as long as manufacturers can maintain or surpass performance levels of the previous material. Critical properties include dielectric strength, flame retardance, chemical resistance, low specific gravity for faster line speeds, and abrasion resistance.

Another strong trend is the demand for increasing functionality. As appliance and electronics manufacturers add more and more features to their products on one hand, and as many of these products shrink in size on the other hand, a dilemma has arisen. How is it possible to squeeze more capabilities into smaller spaces? One answer is moving to thin-wall and ultra-thin-wall cable and wiring for reduced mass.

When manufacturers adopt a new material, they face the need for long-term aging of their wire and cable products to meet UL requirements. This testing takes 150 days, causing delays in the launch of the product and a potential competitive disadvantage. Finding a material that is already listed under the UL reference standard for electrical wires, cable and flexible cords means that products need only undergo short-term aging tests of a mere seven days.

To tackle all these challenges at once, GE Plastics developed flexible Noryl modified polyphenylene oxide resins. These thermoplastics can deliver softness, flexibility, and processing performance that equal or surpass those of PVC, with the added benefits of low, specific gravity and improved abrasion resistance. In addition, because these resins are thermoplastics, they offer a faster-processing alternative, with potential for recyclability, to highly filled flame-retardant polyethylene (FRPE) resins and cross-linked polyethylene (XLPE) materials. The new resins also meet lead-free requirements and provide non-halogenated, non-brominated flame retardance — an increasingly important quality for consumer electronics applications.

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Upgrading from PVC and other traditional materials to flexible Noryl resins offers appliance designers and manufacturers a number of benefits. In fact, some major electronics manufacturers such as HP and Microsoft are already moving away from the use of PVC in anticipation of tighter restrictions. Benefits include:

• Environmental responsibility: Although lead-free formulations of PVC are available, many electronics companies are interested in other alternatives that meet the requirements for lead-free parts and do not contain other halogens, such as chlorine. Flexible Noryl resins are UL 1581-approved flame-resistant materials for appliance wiring. This resin family meets the RoHS directive’s requirements for minimizing the use of brominated or halogenated flame retardants and lead, and its expected restrictions on chlorine. Further, these resins meet WEEE requirements for end-of-life material handling by eliminating the use of bromines.
• Ability to use the same equipment: Changing materials always raises the question of whether new machinery and processes will be needed. Many wire coating manufacturers will find that flexible Noryl resin is compatible for use in the same extruders used to process PVC, FR-PE, flame-retardant thermoplastic elastomers (FRTPE) and other conventional materials, saving the costs of investing in new equipment.
• Faster time to market: Recognition under UL’s 1581 reference standard at 80DegC, 90DegC and 105DegC, allows proposed wire and cable products incorporating these resins to undergo short-term aging tests instead of extended long-term aging tests. Furthermore, more than 30 UL Appliance Wiring Material Style Pages based on the UL 758 standard have been approved for appliance wire and cable products that use the GE materials.
• Faster processing: Flexible Noryl resins offer faster throughput than XLPE or filled FR-PE and FR-TPE materials that use heavy metals, which can rise to the surface and cause snagging. The GE materials can boost line speeds by an impressive three to five times.
• Design flexibility: Flexible Noryl resin grades enable ultra-thin-wall insulation, which enables smaller wire and cable size. Thinner walls allow designers to fit more electronic functionality into limited space, and can reduce weight. For example, replacing traditional 0.4 mm thin-wall cable insulation made of XLPE with 0.35 mm ultra-thin-wall insulation made of flexible Noryl resin results in 27 percent less weight.
• High performance for demanding applications: Typically, the resins offer 20 percent to 30 percent lower specific gravity (weight saving), and increased flexibility vs. highly loaded FR-PE and FR-TPE. In addition, they also provide better abrasion resistance, and excellent chemical resistance.

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With their value-added features and performance enhancements, as well as a solution to global environmental requirements, the flexible Noryl resins offer manufacturers a new way to set their products apart from the competition. In a commodity market, such differentiators as eco responsibility, the ability to produce ultra-thin-wall coatings, reduced cycle times, and UL recognition can give appliance wire and cable makers a distinct edge over competitors that are still using PVC and other stock materials. While commodity resins may be less expensive, the measurable and intangible advantages of these specialized materials can make them a better overall value.


For more information Email: gelit@ge.com