Bondply, also called Bond-Ply, or Bond Ply, which can be either a flexible printed circuit (FPC) material with adhesive + Polyimide (PI) + adhesive structure, or a printed circuit board (PCB) material with an unreinforced, hydrocarbon based thin film adhesive system.
- In flexible and rigid-flex circuits, taking Dupont bondply as example, bondply composites are constructed of polyimide film, coated on both sides with a proprietary B-staged acrylic adhesive. If only coated on single side, it is an another material –coverlay. Bondply is used in-between two conductive layers from different FCCL cores to encapsulate etched details in flexible and rigid-flex multilayer constructions. In real PCB fabrication process, it is always replaced by a coverlay layer and an adhesive layer.It’s key features and benefits includes (1) excellent bond strength affords high reliability; (2) high thermal resistance to facilitate processing; (3) Able to withstand multiple lamination cycles; (4) No refrigeration required for storage; (5) Certified to IPC-4203/1; and (5) RoHS compliant.Also refer to TPI. At MADPCB, bondply or TPI are mainly used for fabricating heavy copper flex and rigid-flex PCBs, especially HDI boards with sharp copper features.
- In rigid boards, taking 2929 bondply as an example, it is an unreinforced, hydrocarbon based thin film adhesive system intended for use in high performance, high reliability multilayer constructions. A low dielectric constant (2.9) and loss tangent (<0.003) at microwave frequencies makes it ideal for bonding multi-layer boards (MLB) made using PTFE composite materials such as RT/duroid 6000 and RO3000 series laminates, filled hydrocarbon resin composites such as RO4000 cores, and specialty thin core laminates. The proprietary cross-linking resin system makes this thin film adhesive system compatible with sequential bond processing while controlled flow characteristics offer excellent blind via fill capability and potentially predictable cutback ratios for designs requiring blind and/or buried cavities. 2929 bondply is compatible with traditional flat press and autoclave bonding.It’s key features and benefits includes (1) Available thicknesses are 1.5, 2 and 3mil; (2)Dielectric constant of 2.9; (3)Dissipation factor of 0.003 at 10GHz; (4) Ideal for multilayer bonding; (5) Excellent blind via fill capability; and (6) Reliable through sequential bonding.