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

We have been taking proactive measures against red phosphorus in AC/DC Power Adapter and switching power supplies since well before the issue recently came into the spotlight. This page introduces some of the thorough measures we have implemented to prevent so-called silent changes.

Red Phosphorus and Ion Migration

Flame retardants are broadly classified as organic or inorganic according to their composition. 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, red phosphorus (P: phosphorus) has been found to accelerate metal migration and deposition in the presence of moisture and an electric field. This phenomenon is known as ion migration and poses a risk of causing short circuits and heat-related incidents in electronic equipment.

Industry Trends Concerning Red Phosphorus

Multiple cases of ion migration problems caused by red phosphorus have been reported in the electronics industry in the past. The following industry developments prompted our company to take an early lead in eliminating the use of 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 Ag (silver), the pin material, between pins within LSI packages, resulting in short circuits. This HDD failure issue had a major impact on the electronics industry and increased industry-wide awareness of metal migration in the presence of phosphorus (P), moisture, and an electric field.

2014: NITE (National Institute of Technology and Evaluation) Report (Industry Case)

However, an incident occurred within the industry suggesting that this knowledge had not sufficiently reached manufacturers supplying plastic raw materials. In 2014, NITE (National Institute of Technology and Evaluation) published a report entitled "Plastic Flame-Retardant Methods and Examples of Problems Involving Flame Retardants," which described 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) in the DC plug.

Our Response: Before the NITE report mentioned above was published, we had already begun eliminating the use of red phosphorus in response to customer requests. No accidents caused by red phosphorus have occurred in our Products.

Our Efforts to Eliminate Red Phosphorus

In response to customer requests, we began eliminating red phosphorus even before the NITE report was published. The following outlines the history of our key initiatives.

Period	Actions Taken
Before the NITE Report	Eliminated red phosphorus from the flame retardants used in insulating sleeves
April 2016 onward	Eliminated red phosphorus from the flame retardants used in plastics (heat-shrink tubing) in areas of DC plugs subject to electric fields. At the same time, we began conducting simplified measurements of phosphorus (P) content during incoming inspections (using an X-ray fluorescence analyzer, with an upper control limit of 1,000 ppm)

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

Ongoing Management System: Preventing Silent Changes

Eliminating red phosphorus is not a one-time measure. Ongoing management is required to ensure that component manufacturers do not make so-called "silent changes" (changes to materials or processes without prior notice). We operate the following management system.

Management of Existing Components

None of the resin materials used in our Products contain red phosphorus, and non-red-phosphorus-based flame retardants are used. We obtain and retain a declaration from each component manufacturer certifying that its components are "red-phosphorus-free" or contain "no intentionally added red phosphorus," ensuring strict management.

Management of Newly Adopted Components

For newly adopted components, we require component manufacturers to explicitly state "red-phosphorus-free" or "no intentionally added red phosphorus" in the component approval document during the approval process.

Quantitative Control Through Incoming Inspection

In addition to management through declarations, we quantitatively measure the phosphorus (P) content during incoming inspections using an X-ray fluorescence analyzer and manage it with an upper control limit of 1000 ppm. This dual system of document control and physical measurement reliably prevents silent changes.

Management Method	Details
Explicit Statement in Component Approval Documents	Require suppliers to explicitly state "No red phosphorus flame retardants used" in their approval documents, contractually preventing silent changes
Obtaining and Retaining Declarations	Obtain declarations from component manufacturers certifying that all resin materials are "red-phosphorus-free" or contain "no intentionally added red phosphorus"
Incoming Inspection Using X-Ray Fluorescence Analysis	Quantitatively measure phosphorus (P) content. Upper control limit: 1000 ppm

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

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