DIN EN 61249-2-44:2017-03

This part of IEC 61249 gives requirements for properties of non-halogenated epoxide nonwoven reinforced core/woven E-glass reinforced surface laminate sheets of defined flammability (vertical burning test), copper-clad for lead-free assembly in thicknesses of 0,60 mm up to 1,70 mm. The flammability rating is achieved through the use of nonhalogenated fire retardants reacted as part of the epoxide polymeric structure. The glass transition n temperature is defined to be 105 °C minimum. The requirements of some properties are divided into different performance classes. The required class shall be declared in the customer's order in order to avoid incorrect deliveries. Halogen-free epoxy resin, with or without fillers, which allows the production of laminates with a glass transition temperature of at least 105 °C. The total halogen content - based on resin plus reinforcing material - is a maximum of 1,500 ppm, whereby the chloride and bromide content in each case is a maximum of 900 ppm. Contrast agents may also be added to the laminate to improve processability, for example to increase contrast during automatic optical testing. Its flammability is determined by the flammability requirements. The unclad side of a single-sided cladded sheet shall have the natural appearance resulting from the curing process. Minor color deviations are permissible. Furthermore, this side of the sheet shall have a gloss that is determined by the surface quality of the pressed sheets or release layers used. Deviations in gloss due to the pressure effect of the gases released during the curing process are permissible. The laminate shall be punchable, cuttable and drillable if the manufacturer's recommendations are followed. Delamination occurring at the cut edges due to the cutting process is permissible, provided that the depth of the delamination is not greater than the thickness of the base material. Delamination on the edges of drilled holes caused by the drilling process is not permitted. Drill holes shall be able to be metallized through into the drill hole without being adversely affected by separation of the material. A suitable method for assessing punchability is the 2M19 method in accordance with IEC 61189-2. The punching force and retraction force shall be agreed between the customer and supplier. The responsible committee is DKE/K 682 "Aufbau- und Verbindungstechnik für elektronische Baugruppen" ("Packaging and interconnection technology for electronic assemblies") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.