DIN EN 61249-4-19:2014-07

This part of IEC 61249 contains requirements for properties of prepreg that is mainly intended to be used as bonding sheets in connection with laminates according to IEC 61249-2-39 when manufacturing multilayer boards according to IEC 62326-4. Multilayer printed boards comprised of these materials are suitable for lead-free assembly processes. However, these prepreg materials may also be used to bond other types of laminates. The prepreg consist of a glass fabric which acts as reinforcement and which is impregnated with high-performance epoxy resin and subsequently precured until B condition. The flammability rating is achieved by using halogen-free additives which are incorporated into the polymer structure. Inorganic fillers may also be added. Furthermore, contrast media may be added to the laminate to improve processability, for example for contrast enhancement in automated optical inspection (AOI). Prepreg according to this standard have a defined flammability (vertical burning test). The flammability rating of fully cured prepreg is achieved by using halogen-free flame-retardant additives contained as integral part in the polymer structure. After curing of the prepreg according to the supplier's instructions, the glass transition temperature is supposed to be at least 170 °C. Prepreg supplied according to this standard shall be qualified. The qualification tests need to be performed to demonstrate that the manufacturer is able to fulfil the requirements of this standard. The qualification tests shall be performed in a laboratory complying with the IEC requirements. The manufacturer shall maintain a data base which reveals the conformity of the materials with this standard, and shall keep these data easily accessible for inspection on demand. The responsible committee is DKE/K 682 "Montageverfahren für elektronische Baugruppen" ("Electronics assembly technology") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.