IEC 61249-8-8:1997

Overview

IEC 61249-8-8:1997 is an international standard published by the International Electrotechnical Commission (IEC) that specifies the requirements for temporary polymer coatings, also known as temporary solder resist coatings or peelable solder masks. This standard forms part of the IEC 61249 series addressing materials for interconnection structures, specifically focusing on non-conductive films and coatings.

The primary purpose of IEC 61249-8-8 is to establish qualifications for peelable solder masks applied to printed circuit boards (PCBs) or panels to protect certain areas during manufacturing processes such as fluxing and mass soldering. These coatings are designed to be easily removable without leaving residues, enabling the exposed contacts to remain clean and untinned for subsequent assembly steps.

Key Topics

• Scope and Application
  The standard applies to temporary solder resist coatings applied mostly by screen printing on finished PCB boards or panels before shipment. It targets protection of specific PCB areas during assembly, with a focus on keyboard contacts and other sensitive zones requiring temporary masking.

• Qualification Requirements
  IEC 61249-8-8 outlines the testing and qualification procedures for temporary polymer coatings to ensure they fulfill performance criteria such as elasticity, absence of pinholes or voids, and ease of removal without residue.

• Adherence Testing
  The standard specifies adhesion testing (pressure-sensitive tape test) ensuring peelable masks do not adhere undesirably to PCB surfaces or through holes, unlike permanent coatings which have different adhesion requirements.

• Limited Requirements Compared to Permanent Coatings
  Certain properties important for permanent solder resist coatings-such as resistance to mold, flammability, hydrolytic aging, electrical insulation properties, and corrosion resistance-are not critical for temporary coatings due to their short-term nature.

• Normative References
  The standard references other IEC documents for general test methods and definitions related to electrical materials and printed boards, including:

  • IEC 60068-2-20 (environmental testing)
  • IEC 61189 series (test methods for electrical materials and interconnection structures)
  • IEC 61249-8-5 (permanent polymer coatings specification)
  • IEC 62326-4-1 (rigid multilayer printed boards specification)

Applications

IEC 61249-8-8 temporary polymer coatings serve important roles in PCB manufacturing and assembly by:

• Protecting critical PCB areas during fluxing, soldering, and other assembly processes.
• Enabling residue-free removal of solder resist masks to expose clean and untinned contact pads for subsequent soldering or testing.
• Supporting quality assurance in printed circuit board production by providing a standardized baseline for peelable solder mask performance and reliability.
• Facilitating complex assembly processes such as multi-step soldering operations where selective mask removal is required.

Manufacturers of PCBs, electronics assemblers, and suppliers of solder resist materials rely on this standard to ensure compatibility, uniformity, and compliance in temporary polymer coatings used in interconnection structures.

Related Standards

• IEC 61249-8-5 – Specification for permanent polymer solder resist coatings, covering more comprehensive and long-term protection properties.
• IEC 61189 series – Test methodologies for electrical materials and interconnection assemblies ensuring proper evaluation of coatings and PCB materials.
• IEC 60068-2-20 – Environmental test procedures relevant to assessing soldering reliability and material performance in harsh conditions.
• IEC 62326-4-1 – Specifications related to multilayer printed boards that might also utilize temporary polymer coatings during manufacturing.

By conforming to IEC 61249-8-8, PCB manufacturers and material suppliers ensure that temporary solder resist coatings meet international benchmarks, facilitating interoperability and quality consistency in electronics production processes.

Keywords: IEC 61249-8-8, temporary polymer coatings, temporary solder resist, peelable solder mask, printed circuit board coatings, PCB protection, interconnection materials, solder resist qualification, electronics assembly standards, IEC solder resist norms.