SIST EN 61249-3-3:2001

Overview

EN 61249-3-3:1999 is a CLC sectional specification for adhesive coated flexible polyester film (PETP) used in flexible printed wiring and flexible printed boards. The standard gives requirements for polyester films coated on one side or both with polyester, acrylic or epoxide type adhesives. Single-sided coated films are intended as coverlay/covercoat materials (including local mechanical/environmental support), while double-sided coated films are intended for use as bonding films in multilayer flexible board fabrication.

Key Topics

The standard focuses on material and application-oriented requirements including:

• Material construction: polyester (PETP) base film with one- or two‑side adhesive coatings.
• Adhesive types: polyester, acrylic and epoxide adhesives suitable for flexible printed wiring processes.
• Intended function: coverlay/covercoat (single-sided) and bonding film (double-sided).
• Performance aspects: properties relevant to flexible printed boards such as adhesion, flexibility and suitability for areas subject to mechanical or environmental stress.
• Manufacturing and quality attributes: material consistency, surface condition and documentation for use in PCB fabrication.

(EN 61249-3-3 defines these topics at a material‑specification level rather than process steps or component design details.)

Applications

This standard is directly applicable to industries and activities involving flexible circuits and interconnects:

• Flexible PCB manufacturers selecting coverlays, covercoats and bonding films.
• Material suppliers producing PETP films with adhesive coatings for electronic interconnects.
• PCB design and process engineers specifying materials for flex assemblies that require local reinforcement or lamination.
• Quality, procurement and compliance teams verifying that supplied films meet a recognized European material specification.

Practical uses include protecting circuit traces, supplying localized mechanical support, lamination/bonding of multilayer flex circuits, and enabling reliable performance under bending, flexing and environmental exposure.

Related Standards

• EN 61249 family - other parts address unreinforced and reinforced base materials for printed boards and interconnecting structures.
• Complementary IPC/CENELEC documents may be consulted for process qualification, test methods and electrical performance criteria.

Using EN 61249-3-3 helps ensure consistent material selection for flexible printed boards, improving reliability and manufacturability when integrating adhesive coated polyester films into flexible electronic assemblies.

Keywords: EN 61249-3-3, adhesive coated flexible polyester film, PETP films, flexible printed wiring, coverlay, bonding film, acrylic adhesive, epoxide adhesive, flexible printed boards.