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Mr. Laminate Tells All
By Doug Sober
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PTFE is About to be Banned by IEC TC111
There, I said it. Technical Committee 111 of the International Electrotechnical Commission (IEC) is preparing to effectively ban PTFE (polytetrafluoroethylene) materials from electronics. As history goes, the electronics industry has focused on only two of the four halogens (bromine and chlorine) to be limited in order to be called “halogen-free” or more accurately “low-halogen.” But now, fluorine is being dragged down too, just because of its location in the periodic table.
Currently, an important standard development activity is taking place in IEC TC 111 in the “Environmental Standardization for Electrical and Electronic Products and Systems” committee. The newly proposed standard, IEC 63031, is titled “Definition of Low Halogen Materials used in Electronic and Electrical Products.” The latest committee draft of this standard is currently under circulation and is being reviewed by each affiliated country’s National Committee, with a closing date for comments of September 15, 2017.
Due to the possible negative impact of this new standard on the fluorine industry, this article will hopefully shed light on the issue and help gather support to revise the scope and related "low-halogen" definition in the current Committee Draft (CD). The result will be the preservation of the long-standing good reputation of the fluoropolymer (PTFE)-based products and prevent confusion, duplication with other regulations, trade limitations, and increased costs.
A History Lesson
In 2001, during an IEC meeting of TC91 (TC52) Working Group 4, we decided that there should be a specification for FR-4 copper-clad laminates that were halogen-free. Several Japanese manufacturers were selling these laminates and prepregs around the world, but there were no specifications to conduct commercial business. Although the turnover was quite small at the time, we knew that this product line would grow.
During the meetings, data was presented that supported both the Japanese industry and the U.S. industry as far as maximum threshold limits were concerned. What we finally compromised on was 900 ppm maximum chlorine,900 ppm maximum bromine and a total requirement of 1500 ppm maximum for chlorine plus bromine. The rest of the Working Group 4 members agreed and the document was completed using the IEC process scheme for standards. IEC 61249-2-21 thus became the defining standard for FR-4 product for halogen-free (low halogen) materials.
But what about fluorine??
The rationale behind the banning of halogens was that some brominated and chlorinated flame retardants, when burned especially at low temperature, produced dioxins and other toxic products. These were bad for human health and the environment in general. To that end, the halogenated flame retardants related to these safety issues have been banned from the electronics supply chain. Other halogenated flame retardants are still in wide use because they are very efficient and do not have deleterious effects on health or safety.
In the electronics industry, the use of fluorine has been limited to those base materials comprised of PTFE resins. The fluorine is not in there for flame retardant purposes but it is intrinsic to the basic performance properties of the resin system, and yes, it does produce a UL94 V-0 flammability rating for a laminate base material when combined with woven E-glass reinforcement. As opposed to some of the brominated and chlorinated flame retardants, PTFE has not shown to be an issue safety-wise. In fact, when you think of PTFE (Teflon®) cooking utensils, you think of things that are completely inert. We eat out of them even after cooking at high temperatures.
So, at the time the IEC did not include the fluorine halogen in the halogen-free discussion, and neither did the IPC Halogen-Free Subcommittee which wrote a white paper on halogen-based materials used in our industry. They also chose to give fluorine a free pass. The title of this document is: “IPC White Paper and Technical Report on the Use of Halogenated Flame Retardants in Printed Circuit Boards and Assemblies (Correcting the Misunderstandings on ‘Halogen-Free’)"(2).
Once the limits had been clearly established for bromine and chlorine for base materials, IPC and JEDEC proposed a joint standard that would define other elements of the electronics supply chain including connectors, components, soldermask, conformal coatings, electronic housings and cases as well as power cords. This document was named IPC/JEDEC Joint Standard 709 and the title was, “J-STD-709 Definition of Maximum Limits on the Low-Halogens Bromine & Chlorine Used in Materials for Certain Electronic Components and Assemblies"(3).
Notice anything missing in this title? There is no reference to fluorine. This document was later published only by JEDEC and not by IPC. However, the title and contents only referred to restrictions on chlorine and bromine content. A fluorine requirement was not added here because it did not pose a threat to health or the environment. There is also specific reference as to why fluorine and iodine were not included in the JEDEC standard in the Annex C (informative) titled: “Clarification for including only bromine and chlorine in the definition of low-halogen materials.”
The IEC Technical Committee 111 picked up the JEDEC document and published it as a PAS (Publicly Available Standard)—“PAS 63015: JOINT JEDEC/ECA STANDARD JS709B Definition of ‘Low-Halogen’ For Electronic Products” and made it a part of their standards for publication. The JEDEC document was imported as an IEC standard directly due to cooperation between JEDEC and IEC. But once published, the TC-111 members decided to re-write the already published standard and began an IEC New Work Item Proposal.
The second draft of this document is now being circulated through the member countries for comments. Whereas IPC, IEC TC91, JEDEC and JPCA all address the environmental standards by limiting bromine and chlorine in base materials, PWBs, assemblies and final electronics, the new proposed TC 111 document below also puts fluorine in “just because it is in the halogen column of the periodic table.” Base materials made from PTFE have never, to my knowledge, had any issue with health and environmental concerns. In fact, fluoropolymers possess low inherent hazard and unique functionality to multiple industries, including health care, food contact applications, aerospace, chemical processing, building construction, automotive, electronics, energy, environmental protection, and outdoor & technical apparel.
The Bottom Line
If this proposed document were in fact approved by the member countries and published by IEC, it would essentially outlaw PTFE-based materials from use in electronics. The title of this document is “Definition of Low Halogen Materials used in Electronic and Electrical Products.” The exact requirement statement in it is as follows:
Materials defined as “Low Halogen” shall contain less than 0,9% (by mass) total elemental halogen content (F+Cl+Br+I) and meet the thresholds of all halogenated substances in IEC 91 62474 database.
The standard is in the Committee Draft Phase which means it is being circulated for comments to all the IEC TC111 member countries. The deadline for comment submission is September 15, 2017.
The only recourse is to contact your country’s IEC National Committee and the IEC TC111 representatives, and the sooner the better.
For a copy of the draft document, please email email@example.com.
- International Electrotechnical Commission, information on IEC TC 111.
- IPC white paper: IPC-WP/TR-584A, final draft May 2007.
- IPC/JEDEC STD-709 (copy of proposed standard for ballot, reference only, since revised).
Stephen Tisdale has been involved in the electronics industry for 41 years and engaged in standards activities in IPC, JEDEC and IEC for most of his career.
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