Overview
IEC 61249-2-27:2012 is an international standard published by the International Electrotechnical Commission (IEC) that specifies requirements for materials used in printed boards and other interconnecting structures. This part of IEC 61249 focuses on reinforced base materials, specifically bismaleimide/triazine resins modified with non-halogenated epoxide, combined with woven E-glass laminate sheets. The materials are copper-clad and have defined flammability characteristics, tested by a vertical burning test. The standard ensures a minimum glass transition temperature of 160 °C and specifies thickness ranges from 0.03 mm up to 1.60 mm.
The key objective of IEC 61249-2-27 is to specify the physical, electrical, and flammability properties of these laminate materials for high-performance and safety-critical printed circuit boards (PCBs). Non-halogenated fire retardants integrated into the polymer structure contribute to achieving the required flammability rating while maintaining environmental responsibility.
Key Topics
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Material Composition
The laminate sheets consist of bismaleimide/triazine resin systems reinforced with non-halogenated epoxide woven E-glass fabric. Copper is clad onto these sheets, providing excellent electrical conductivity and structural integrity.
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Flammability Requirements
The material meets defined flammability standards verified by the vertical burning test, an essential safety feature. The use of non-halogenated inorganic and organic compounds ensures improved fire retardancy without halogen-related environmental concerns.
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Physical Properties
Thickness tolerances, dimensional stability, surface quality (such as pits, dents, wrinkles, scratches), bow and twist limits, and other mechanical characteristics are specified to guarantee material uniformity and performance in manufacturing processes.
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Electrical and Thermal Performance
Electrical properties such as dielectric strength and insulation resistance are defined to ensure optimum electrical performance. The minimum glass transition temperature (Tg) of 160 °C ensures thermal stability in demanding applications.
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Quality Assurance and Testing
The standard outlines quality system requirements, inspection procedures, and certification practices to ensure consistent product quality. It also includes guidance on packaging, marking, and ordering information for reproducibility and traceability.
Applications
IEC 61249-2-27:2012 materials are critically important for high-reliability printed circuit boards used in advanced electronics, including:
- Aerospace and defense electronics requiring high thermal resistance and flame retardancy
- Telecommunications equipment where durability and electrical integrity are vital
- Industrial electronics with demanding mechanical and environmental conditions
- High-speed digital and microwave circuits taking advantage of stable dielectric properties
- Automotive electronics where safety-critical flame retardant materials are mandated
By adhering to the IEC 61249-2-27 standard, manufacturers ensure that printed boards meet stringent fire safety regulations while delivering reliable electrical performance.
Related Standards
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IEC 61249 Series
The IEC 61249 family covers materials for printed boards and interconnecting structures, including various resin systems, reinforcements, and laminate constructions.
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IEC 60384 Series
Standards for capacitors, some of which utilize similar materials for safe and stable electrical performance in harsh environments.
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UL 94
Recognized testing standard for flammability of plastic materials, complementing IEC’s vertical burning tests.
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IPC Standards
Such as IPC-4101 for base materials specifications, relating to materials covered by IEC 61249 to ensure interoperability in PCB manufacturing.
Using IEC 61249-2-27 as part of a comprehensive standards compliance approach ensures that materials meet international requirements for safety, durability, and performance in printed circuit board fabrication.
Keywords: IEC 61249-2-27, bismaleimide/triazine laminate, printed boards, copper-clad laminate, non-halogenated epoxide, woven glass laminate, flammability standard, vertical burning test, fire retardant PCB materials, glass transition temperature, electrical properties, dimensional stability, PCB base material standard.
Open preview (PDF)Materials for printed boards and other interconnecting structures - Part 2-27: Reinforced base materials clad and unclad - Bismaleimide/triazine modified with non-halogenated epoxide woven glass laminate sheets of defined flammability (vertical burning test), copper-clad
