Method of manufacturing molded articles

Abstract

A method of manufacturing molded parts, preferably having the same wall thickness, from mixtures of cellulose and/or lignocellulose fibers with more than 20% by weight of thermal binders, in which the molded article results from application of heat and pressure to fiber mat prefabricated therefrom. In a first step, the fiber mat undergoes preliminary compression as a planar, endless matted fiber fleece, with only a small degree of compression of the fiber composite, the matted fiber fleece containing at least 2% by weight of a binder which cross-links under heat, its 'start-off temperature', i.e. the temperature at which cross-linkage begins, being lower than the softening temperature of the thermoplastic binder. The cellulose and/or lignocellulose fibers are provided, before production of the fiber composite, with a surface finish of the cross-linking binder. The fiber mat, slightly compressed in the first step, is in a second step heated in the form of a blank or of a web to at least the start-off temperature of the fiber finish. Compression is carried out before shaping of the molded article, which is held in this condition of density for the duration of the cross-linkage of the fiber finish. Finally the preferably planar fiber mat, is shaped by the application of pressure to form the finished molded article, in a press tool whose temperature lies below that of the heated fiber mat.