Electrical/Electronics

Miniature switches are primarily used in the European and Asian markets, which is why UL certification is often not required. The main components are the housing, arc chamber and guides, and the levers. Alongside the mechanical and thermal characteristics (TI/RTI), another vital aspect of all these components is flame resistance via a glow wire test (GWFI), varying from 650C for the levers to 960C for the housings. Insulation is also a necessary property, through resistance to creeping currents (CTI)>450V, as well as a choice of colours ranging from white (RAL 9003) to light grey (RAL 7035).

Compared with miniature switches, the voltage and current levels in this instance are much higher. For this reason, the requirements with regard to mechanical, thermal, insulation and flame resistance performance are much stricter.
The main requisites are UL-94 V0 and CTI >450V, as well as continuous use temperatures with Electrical TI/RTI >130°C. RadiciGroup has developed products suitable for these applications and based on PA6, PA66 and PPA, using traditional flame retardant technologies based on halogens and red phosphorus (Radiflam® A AE; Radiflam® A AF). In addition, products free from halogens and red phosphorus have also been developed (Radiflam® A HF, Radiflam® S HF, Radiflam® Aestus T2 HF). We also have materials (in a version that is free from halogens and red phosphorous) that use mechanically-recycled polyamides, for a lower environmental impact (Renycle® A HF0).

Unlike switches which only have an on/off position, contactors and relays open and close the circuit to ensure a constant power supply to the equipment they protect.
The main requisites are glow wire resistance (GWFI) 960°C, CTI 600V, UL-94 V0 and, for household appliance applications, flameless glow wire resistance (GWEPT) 750°C according to IEC 60335, continuous use temperature TI/RTI Electric >120°C, colour usually light grey (RAL7035) and dark grey (RAL 7012). RadiciGroup offers a selection of products, ranging from PA6 (Radiflam® S HF), PA66 (Radiflam® A HF) and PPA (Radiflam® Aestus T2 HF), without red phosphorus and halogens. Alongside these products, we have also introduced a range of materials with a lower environmental impact, based on PA6 (Renycle® S HF0) and PA66 (Renycle® A HF0) and obtained from mechanical recycling.

Household appliance connectors must ensure safety in conditions ranging from humid heat for washing machines and dishwashers to dry cold for refrigerators and freezers and high temperatures for ovens. This calls for versatile materials that comply with IEC 60335 by passing the flameless glow wire test (GWEPT) at 750°C, are classified as UL-94 >V2 for the US market, ensure resistance to creep currents >400V and have properties of elongation at yield (to facilitate snap-fit installation) and colourability, as well as an RTI of >105°C. For these applications (in addition to the traditional Radilon® and Radiflam® materials), RadiciGroup has also developed a Radiflam® A (based on PA 66) and S (based on PA6) HFG1 product range, which meets the requirements of IEC 60335 and uses a next generation flame retardant system without red phosphorus or halogens.

The elimination of lead-containing eutectic alloys has led to an increase in alloy temperature >30°C, in addition to the switch from wave welding to reflow welding, resulting in a further increase in temperature up to 260°C. This has led to the transition from materials such as polybutylene terephthalate (PBT) to PPA and liquid crystal polymers (LCP). The main requisites for these applications are flame resistance according to UL-94 V0 at thicknesses up to 0.2 mm, no blistering, melting temperature >300°C, and stable colours after the reflow oven phase at 260°C. RadiciGroup’s PPAs in the Aestus® T1 and T2 line, based on sustainable anti-flame technology without red phosphorus or halogens, are able to meet all these needs.

The introduction of electric vehicles has ushered in a technological revolution in the development of connectors. We have moved from the transfer of data or relatively low energy levels to high power ratings and a requirement for materials with flame resistance according to UL-94 V0, flameless glow wire resistance GWIT at 750°C, insulation at temperatures of 150°C (dielectric strength, resistivity), an orange colour (RAL 2003) with only minimal variation after 1000 hours at 130°C, and resistance to creeping currents through CTI (comparative tracking index)>600V and IPT (Inclined Plane Tracking)>1.5kV. RadiciGroup has developed Radiflam® A (PA66), Radiflam® B (PBT), Radiflam® S (PA6) and Radiflam® Aestus (PPA) materials with a sustainable flame resistance system without red phosphorus or halogens, CTI>600V, and a stable orange colour after 1000 hours at 130°C.

There are two terminal block categories: DIN Rail and terminal blocks for printed circuit boards (PCBs). In the first instance, flame resistance according to UL-94 V0 at thicknesses of 0.2 mm is required, along with resistance to creep currents (CTI) 600V, RTI (relative temperature index) with impact>110C, colourability and elongation at yield>5%. In the second instance, there is the added requirement to pass the weld through the reflow oven. RadiciGroup’s solutions for DIN terminal blocks are Radiflam® AFR and AFRX (PA66) (unfilled) with a flame retardant system without red phosphorus or halogens, while for PCB terminals the selection is based on PPA – for example, Radiflam® Aestus T2 with a flame retardant system without red phosphorus or halogens.

Connectors for photovoltaic applications must have flame resistance (GWFI 960°C), UL- 94 V0 and insulation properties (CTI>600V and IPT>1kV), in addition to passing strict mechanical tests including impact at -40°C. To meet these requirements, we have developed the products Radiflam® A RV250Z AF and Radiflam® A RV250AF2, with a flame retardant system based on red phosphorus.