DIN EN 61249-2-27:2013-09

This part of IEC 61249 gives requirements for properties of bismaleimide/triazine modified with non-halogenated epoxide woven E-glass reinforced laminated sheets of defined flammability (vertical burning test), copper-clad in thicknesses of 0,03 mm up to 1,60 mm. The flammability rating is achieved through the use of non-halogenated inorganic and/or organic compounds acting as fire retardants. These fire retardants are contained as part of polymeric structure or in addition to it. The glass transition temperature is defined to be 160 °C minimum. Some property requirements may have several classes of performance. The class desired should be specified on the purchase order, otherwise the default class of material may be supplied. The sheet consists of an insulating base with metal-foil bonded to one side or both. The resin system consists of non-halogenated epoxide modified cyanate ester resulting in a laminate with a glass transition temperature of 160 °C minimum. The maximum total halogens contained in the resin plus reinforcement matrix is 1 500 ppm, with a maximum chlorine of 900 ppm and maximum bromine being 900 ppm. Contrast agents may be added to the laminate to enhance processing such as automated optical inspection (AOI). Other clauses deal with the electrical properties and non-electrical properties of the copper-clad laminate. The unclad face of a single side clad sheet shall have the natural appearance resulting from the curing process. Small irregularities in colour are permitted. The gloss of the unclad face shall be that given by the press plate or release foil used. Variations of gloss due to impact of pressure of gases released during the curing are permitted. The laminate thickness may be ordered to include or exclude the copper foil contribution as specified in the purchase order. As a general rule laminates less than 0,8 mm are measured excluding copper and laminates greater or equal to 0,8 mm are measured including copper. Subsequently, the non-electrical properties of the base material after complete removal of the copper foil are dealt with. The etched specimens shall be inspected to verify that nor surface or subsurface imperfections of the material exceed those shown below. The specimens shall be inspected using an optical aid apparatus which provides a minimum magnification of 4X. Referee inspection shall be conducted at 10X magnification. Lightning conditions of inspection shall be appropriate to the material under inspection or as agreed upon between user and supplier. Another clause deals with quality assurance. Laminates furnished under this standard be qualified. Qualification testing shall be performed to demonstrate the manufacturer's ability to meet the requirements of this standard. Qualification testing shall be conducted at a laboratory compliance with IEC laboratory requirements. A list of the normal qualification tests can be found in Annex C. The manufacturer shall retain on file the data which supports that the materials meet this specification and shall be readily available for review upon request. If not otherwise specified in the purchase order, laminate sheets shall be marked with the manufacturer's designation containing the manufacturer's symbol, nominal thickness, copper clad and lot number. Marking shall remain legible during normal handling but be readily removable prior to use of the material. Cut-to-size panels shall be identified by marking on the package. Informative Annex A contains engineering information. Information in this annex does not detail material property requirements. The information is intended as a guideline for design and engineering purposes. Users of this standard are encouraged to supply information to be included in the annex. It is expected that the materials according to this standard show the typical values indicated hereafter for the properties given. Other clauses give chemical properties, electrical properties, flammability properties, mechanical properties, physical properties and thermal properties. Informative Annex B contains information on common laminate constructions. The information does not represent requirements for material designs with certain thicknesses, but are only intended as a general guideline for design and engineering purposes. Other designs with higher performance properties can also be available on the market for a specified material thickness. Informative Annex C contains a guideline for qualification and conformance inspection. The information in this annex does not represent requirements for qualification and conformance inspection. The current quality and conformance inspections shall be specified in the quality system of the supplier for materials supplied in accordance with this standard. Test data and summaries of test results shall be available for support of the test schemes used for qualification and conformity inspection. If the manufacturer does not have a quality system, this annex shall be used. 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.