Our company's response regarding the use of red phosphorus (ion migration) in AC/DC Power Adapter

Our company has proactively implemented measures against red phosphorus in AC/DC Power Adapter and switching power supplies well before the issue recently came into the spotlight. This page introduces some of our thorough measures against so-called silent changes.

Red Phosphorus and Ion Migration

Flame retardants are broadly classified into organic and inorganic types depending on their components. Red phosphorus is classified as an inorganic flame retardant, and flame retardants containing red phosphorus (red phosphorus-based flame retardants) are added to certain resins to improve the flame resistance of plastics.

However, it has been confirmed that red phosphorus (P: phosphorus) promotes metal migration (movement and deposition) in the presence of moisture and an electric field. This phenomenon is called ion migration and poses a risk of causing short circuits and overheating accidents in electronic devices.

Industry Trends Related to Red Phosphorus

Issues of ion migration caused by red phosphorus have been reported in multiple cases across the electronics industry in the past. The following outlines industry trends that prompted our company to proactively work on eliminating red phosphorus.

Around 2000: HDD Failure Issue (Industry Case)

Around 2000, numerous hard disk drive (HDD) failures occurred in the PC and PC server industries. The cause was migration of the pin material Ag (silver) between pins inside LSI packages, resulting in short circuits. This HDD failure issue had a significant impact on the electronics industry and raised industry-wide awareness of the phenomenon in which metals migrate in the presence of phosphorus (P), moisture, and an electric field.

2014: Report by NITE (Products) (Industry Case)

However, an incident occurred within the industry suggesting that this knowledge had not sufficiently permeated manufacturers supplying plastic raw materials. In 2014, NITE (National Institute of Technology and Evaluation) published a report titled "Flame-Retardant Methods for Plastics and Trouble Cases of Flame Retardants," describing an accident in which the secondary-side DC plug of an AC/DC Power Adapter overheated and deformed. The cause of this accident was identified as migration caused by red phosphorus added as a flame retardant to the insulating sleeve resin (PBT: polybutylene terephthalate) of the DC plug.

Our Response Status: Our company began efforts to eliminate red phosphorus based on customer requests even before the above NITE report was published. No accidents attributable to red phosphorus have occurred in our Products.

Our Initiatives Toward Eliminating Red Phosphorus

In response to customer requests, we began eliminating the use of red phosphorus even before the NITE report was published. The main milestones of our efforts are shown below.

Key Point: We began eliminating red phosphorus before the NITE materials were published. By taking proactive measures before this issue became widely recognized across the industry, we have eliminated the possibility of risks derived from red phosphorus entering our customers' Products.

Ongoing Management System: Prevention of Silent Changes

Eliminating red phosphorus is not a one-time action; continuous management is required to prevent component manufacturers from making so-called "silent changes" (changes to materials or processes without prior notice). We operate the following management system.

Management of Existing Components

All resin materials used in our Products do not contain red phosphorus and use non-red-phosphorus flame retardants. We obtain and retain certificates from each component manufacturer stating "No red phosphorus content" or "No intentional addition of red phosphorus," ensuring thorough management.

Management of Newly Adopted Components

For newly adopted components, during the approval process we require component manufacturers to clearly state "No red phosphorus content" or "No intentional addition of red phosphorus" in the component approval document.

Quantitative Control Through Incoming Inspection

In addition to certificate-based management, we quantitatively measure the phosphorus (P) content using X-ray fluorescence (XRF) analysis during incoming inspection and control it with an upper management limit of 1000ppm. Through a dual system of documentation control and physical measurement control, we reliably prevent silent changes.

Related Pages

For more details about our parts and materials management and quality control systems, please also see the following pages.

Our Quality Initiatives:
Our Quality Initiatives ／ RoHS2 Compliance ／ Component Supplier Selection Method ／ Quality Control System for Our AC/DC Power Adapter