Electronics industry uses heavy metals like lead solder, exotic and costly materials like superconductors and rare metals, volatile-organic compounds (VOCs) for degreasing and to strip solder mask, acids for etching, etc. Since fire is always a possibility with electrical and electronic devices, potentially combustible materials like plastics usually require addition of flame-retardant packages, unless they are inherently FR, and those packages have generally been halogenated. To obtain colors and special effects consumers seem to crave, traditional color houses often used cadmium-based colorants. Many processes and materials have gotten much cleaner over the years like lead-free soldering, cadmium-free colorant packages, and low- or no-halogen flame retardants. The environmental pressure to become greener is increasing. Many government entities are developing mandates for cleaner materials and processes. Even the non-governmental organizations (NGOs) like environmental groups and consumer advocates are also demanding for the electrical and electronic industries to become cleaner. Electronic industry is emphasizing to ensure the materials and processes used to produce these devices meet much tougher environmental standards.
Ticona Engineering Polymers has introduced a second-generation, low-viscosity grade of its linear PPS produced by a new process that reduces residual chlorine by a factor of 5. While PPS is inherently flame-retardant (typically UL� 94 V-0 down to 0.38 mm for glass-reinforced grades), residual chlorine is a natural byproduct of its polymer production process. The company introduced its first next-generation low-halogen PPS grade produced with the new process, which reduces residual chlorine from the 5,000 ppm levels found in conventional PPS grades to values below 900 ppm. This significantly higher level of cleanliness meets a Restriction of Hazardous Substances Directive (RoHS) and a proposed IEC industry standard 61249-2-21 of less than 900 ppm of chlorine or bromine. This, in turn, allowed the first-generation high-purity grade to replace other low-halogen, high-temperature flame-retardant plastics such as high temperature polyamide. Scientists have now developed the new ultra-pure formulation with viscosity values measuring 30-50% lower, depending on test method used, so it could be run in existing PPS tooling without modification for processors whose customers wanted PPS and needed a greener solution for their connectors.
With low halogen content standards becoming commonplace in the electronics industry, Chevron Phillips Chemical Company LP's Engineering Polymers group has introduced several new Ryton� polyphenylene sulfide (PPS) resin grades with chlorine content of less than 900 parts per million. Ryton� PPS R-4-280 is a 40% glass-filled PPS, offering electronics and electrical component manufacturers a strong resin well suited for connectors, bobbins and other hard disc drive (HDD) structural applications. Ryton� PPS R-7-190 is a glass and mineral-filled PPS for applications where dimensional stability, stiffness, and electrical properties are required. The new grades are designed specifically for the electrical, electronics, and computer industry by using the latest technology to produce these resins and are achieving the reduction in chlorine content without sacrificing any of the resin properties, such as excellent flow. Using new polymerization process technology, it is able to achieve the desired targets in chlorine content. This process technology allows PPS polymer to be produced in a wide variety of molecular weights, which provides the capability to produce a range of molding compounds from which to choose. Ryton� PPS offers superb value for electrical and electronic applications. With excellent flow and low shrinkage for precision molding of connectors and sockets, and superior stiffness and mechanical integrity for reliable assembly, Ryton� PPS is one of the most stable material choices for electrical applications. Additionally, all Ryton� PPS compounds have UL94 V-0 flammability ratings without the use of flame retardant additives.