FIELD: foam materials.
SUBSTANCE: present invention relates to a block of fibre-reinforced polyurethane/polyisocyanurate foam of a thermally insulating body of a sealed and thermally insulated tank and to a method for its manufacture. Said block is composed of cells storing a gas having low thermal conductivity, the block density is from 30 to 300 kg/m3, the average density of the fibres is from 1 to 60% by weight of the fibres, the width of the block is at least 10 cm, and the thickness from the bottom surface to the upper surface of the block at least 10 cm. The density of the fibres increases along the thickness of the block from the lower surface to the upper surface of the block from the lower density range from 1 to 9.99% by weight of the fibres to the upper density range from 10 to 35% by weight of the fibres. The method for manufacturing a block includes a) mixing the chemical components necessary to obtain a polyurethane/ polyisocyanurate foam, b) impregnating with the help of a gravitational flow the above mixture of a group of fibrous reinforcements arranged in superimposed layers and having variable densities, c) formation and expansion of a reinforced foam fibres. The expansion of fibre-reinforced foam is free. Foam expansion is physically limited by the walls of the dual belt laminator.
EFFECT: resulting fibre-reinforced polyurethane/polyisocyanurate foam has excellent mechanical and thermal characteristics, while maintaining its mechanical properties throughout the foam block, as well as its shape/structure when the block is in use, i.e. in a very different thermal environment between its top and bottom surfaces.
16 cl, 6 dwg, 4 tbl
