Abstract: A moulding composition comprising (a) a melamineformaldehyde resin having a molar ratio of melamine to formaldehyde in the range 1:1.5 to 1:2.5 which upon hardening is capable of withstanding heating at 200.degree. C concerned for 2 hours in air without causing significant structural damage or color change to moulded articles made from moulding compositions in which it has been incorporated, (b) an accelerator derived from a mono- or dibasic organic acid, (c) an inorganic filler having low adsorption characteristics and an oil adsorption value of 10 to 40, (d) a further inorganic filler and (e) an external lubricant comprising at least one carboxyorganosiloxane esterified with an alcohol containing up to 4 carbon atoms and the process of preparing said moulding compositions.