Improved EMI Shielding Consistency of Single Pellet Conductive Plastics

Wednesday, February 8, 2017 by Sealing & Shielding Team

For designers of electronics enclosures, conductive plastics offer the benefit of lighter weight coupled with cost effective injection molding. But for years, using traditional blended plastic pellet materials, the EMI shielding results were often inconsistent at best, leaving many engineers grasping for something better. There is a new single pellet alternative on the market, promising improved EMI shielding consistency, created using tightly controlled conductive material that delivers unparalleled EMI shielding performance and superior processing.

Parker Chomerics has solved the problem of inconsistent EMI shielding effectiveness in single pellet plastic systems with the processing found in PREMIER^TM PBT-225, a conductive plastic pellet system with consistent EMI shielding. This novel material was developed by leveraging our materials science expertise in both EMI shielding and injection molding.

More shielding effectiveness, less weight

Metal to plastic conversions not only eliminate 35% of the housing weight (as compared to aluminum), but also provide up to a 65% cost reduction by eliminating secondary operations such as assembly and machining. PBT-225 is a single pellet, polybutylene terephthalate (PBT) based, electrically conductive plastic, making metal to plastic housing conversions not only possible, but usually the best solution for demanding electronics applications.

Why excellent hydrolysis resistance is important

Many plastics will typically degrade over time when exposed to water and steam. Automotive applications represent a great hydrolysis risk, as plastics are continuously exposed to harsh conditions for an extended period of time. Because of this, PBT-225 was specifically developed to deliver excellent hydrolysis resistance and provide a more reliable alternative solution to traditional cube blend conductive resin systems. The goal was to help improve long term aging performance when exposed to typical heat and humidity conditions found on automotive applications.

Single pellet technology vs. multi-pellet blends

Traditional multi-pellet cube blends consist of two or more material pellets, mixed at pre-determined ratios. The very nature of mixing separates materials, resulting in variations which can never really be eliminated.

The chart below shows typical observed performance variations which result from the inherent variation in mixing two pellets together - you can never get rid of the variation.

Improved EMI Shielding Consistency of Single Pellet Conductive Plastics, Parker Chomerics, Premier PBT-225

The single pellet composition of PBT-225 eliminates any inconsistent mix ration associated with traditional multi-pellet blends. Its long stainless steel fibers increase shielding effectiveness, along with the glass reinforcement for mechanical strength.

Typical applications:

Automotive Electronic Housings
Connector Bodies
Motor Housings
Sensor Housings
Infotainment Enclosures
Military Handheld Devices
Industrial Metering Devices
Faceplates
Base Stations
Military Housings
Life Science Enclosures
Telecom Equipment
IT Rack and Server Components
Heavy Duty Connectors
Renewable Energy Housings and Connectors
Non-Critical Power Generation Enclosures, such as smaller housings or enclosures within a power generation system

Help put PBT-225 to work for you

Parker Chomerics Application Engineers can help with your single pellet shielded plastic needs. Please contact a Parker Chomerics Applications Engineer via email, or by calling 781-935-4850.

Download the datasheet here.

improved emi shielding consistency of single pellet conductive plastics, Jarrod Cohen, Parker Chomerics Division