Premix Thermoplastics Introduces New EMI Shielding Compounds

Milton, WI — Premix Thermoplastics, Inc., a custom compounder of electrically conductive thermoplastic compounds, has introduced a full line of EMI shielding compounds for electronic enclosures called PRE-ELEC® EMI. These new products complete Premix¹s line of EMI shielding compounds for the complete electronics enclosure. Premix has, or can develop, specialty compounds to solve EMI problems in most electronics enclosures. These materials offer one-step EMI solutions.

Available in virtually any thermoplastic resin system, PRE-ELEC EMI compounds utilize stainless steel fibers, carbon fibers, or nickel coated carbon fibers to provide EMI shielding capability. Presently these compounds are available in PP, ABS, POM, PC, PBT, PA-6, PA-66, PPS, PSul, PES and PEEK. Other polymer systems that contain these conductive additives are TPU¹s, and various fluoropolymers.

Compounds utilizing stainless steel fiber additives are available in either a fully compounded form or a dry blended form. With the dry blended form, all of the additives in the compound are in the resin except the stainless steel fibers. These are blended into the resin in the form of a concentrate, thus preserving the fibers in a linear manner, which enhances the EMI shielding capability. The physical and thermal properties of both the fully compounded and the dry blended forms are identical.

Compounds using carbon fibers or nickel coated carbon fiber additives are available only in fully compounded forms. Compounds containing 30% carbon fiber additives can provide >30 dB electromagnetic interference attenuation. At 40% carbon fiber, it is possible to achieve >40 dB shielding effectiveness (SE), and at 50% carbon fiber >50 dB SE can be obtained. Nickel coated carbon fibers can be effective with as little as 15% in the compound, and they can provide upwards of 90 dB shielding effectiveness at higher loadings.

The new PRE-ELEC EMI compounds were developed to complement Premix¹s PRESEAL® product line, which is based on SEBS elastomer and filled with a variety of silver coated and/or nickel coated particles. PRESEAL compounds are used for injection molding and extruding EMI gasketing materials. They provide an ideal replacement for silicone gasketing materials because they are easier to process and are recyclable (scrap can be reground and remolded or extruded). Most PRESEAL compounds provide 90 dB or more of shielding effectiveness; and some compounds have compression set as low as 30%.

SOURCE: Premix Thermoplastics, Inc.