Controlled Flow Prepreg
Low-flow prepreg is engineered to have a controlled melt viscosity that results in controlled low flow used in laminating rigid flex printed circuits or bonding heat sinks to printed wiring boards.
Characterized by a high melt viscosity, low-flow prepregs do not flow excessively in heat sink cutouts or past the edge of the rigid segment of a rigid-flex board. This enables the insertion of devices into cutouts and flexibility of the flex section of the board is maintained.
Arlon manufactures a wide range of low-flow prepregs with polyimide or epoxy-based resin systems designed for a variety of heat sink and rigid-flex bonding applications. Individual product lines may also have some variation in available glass styles and flow ranges to further provide optimized materials for specific applications.
Arlon’s 38N and 37N polyimide resins have a glass transition temperature of 200°C and are specifically designed for high layer count rigid flex where thermal performance is required. Primarily used in military or aerospace applications, Arlon’s 38N is specifically engineered for greater adhesion to Kapton® surfaces used in rigid flex printed circuit boards. Both 38N and 37N meet the requirements of IPC-4101E/42.
Arlon manufacturers epoxy based low-flow prepreg for use in commercial, medical, military and aerospace rigid flex PWB’s or heat sink bonding applications. Arlon’s 47N Tetrafunctional modified epoxy resin system has a glass transition temperature of 130°C and is optimized to bond to aluminum and copper heat- sinks with typical lap shear above 1000 PSI. 47N meets the requirements of IPC-4101E/21.
49N is a low-flow epoxy prepreg engineered for bonding multilayer epoxy rigid-flex PWB’s or attaching heat- sinks to multilayer epoxy PWBs. With a Tg of 170°C, the prepreg can be used in high-performance or high-temperature applications and meets the requirements of IPC-4101E/26.
51N is a non-DICY multifunctional epoxy low flow prepreg system designed to provide high reliability through lead-free solder operations. 51N has high thermal stability with a decomposition temperature of greater than 350°C and a 170°C glass transition temperature, this low flow prepreg is ideal for use in complex rigid-flex printed wiring boards and meets the requirements of IPC-4101E/126.