Adhesives Selection for FPC Fixation: Recommended Grades for Solder Joint, NTC and Rigid‑Flex Reinforcement

Adhesives for FPC fixation shall feature flexibility, low stress, good adhesion to PI substrates, excellent flex resistance and compatibility with high-speed dispensing.For rapid reinforcement of solder joints and leads, you may evaluate Elaplus UV 1013 or UV 1018. UV 1017 is recommended for rigid-flex transition areas without dynamic bending requirements. For large-area flexible conformal protection, UV Coating 9060-M or UV SIPC 3301 are available. SIPC 1857-1 can be assessed for flexible fixation of NTC sensors and leads. Why do failures frequently occur at solder joints and rigid-flex interfaces of FPCs? The FPC substrate itself withstands bending, whereas solder joints, chips, connectors and adhesive layers are generally stiffer than the flexible circuit. When the FPC undergoes bending or vibration, stress tends to concentrate at the following locations: If the fixing adhesive features excessively high modulus and is applied over an overly large area, the reinforcement layer may conversely become a new crack initiation boundary. Adhesives used on FPCs mainly serve for SMD component fixation, flexible conformal protection, wire encapsulation and NTC sealing. After curing, the adhesives must remain flexible to avoid impairing the bendability of flexible circuits. Recommended adhesive grades for FPC solder joint reinforcement UV 1013: Flexible UV Fixing Adhesive UV 1013 is a UV-curable modified acrylate adhesive with semi-thixotropic property and outstanding toughness. Recommended applications: Its semi-thixotropic consistency enables the adhesive to wrap solder joints while minimizing excessive flow-out. UV 1018: Balanced fixation and stress buffering UV 1018 suits rapid encapsulation of FPC components, solder joints and partial circuits, striking a balance between curing speed and flexibility. Recommended applications: Adhesive selection for rigid-flex transition zones UV 1017: Local high-strength reinforcement UV 1017 is designed for rigid-flex transition areas requiring high bonding strength without continuous dynamic bending. Typical applications: UV 1017 is not suitable for large-area coverage over primary dynamic…