Methods for manufacturing molded sheets having a high starch content

摘要

Methods are disclosed for manufacturing sheets having a starch-bound matrix reinforced with fibres and optionally including an inorganic mineral filler. Suitable mixtures for forming the sheets are prepared by mixing together (10) water, unmodified and ungelatinized starch granules, a cellulosic ether, fibres, and optionally an inorganic mineral filler in the correct proportions to form a sheet having desired properties. The mixtures are formed into sheets by passing them between one or more sets of heated rollers (40) to form green sheets. The heated rollers (40) cause the cellulosic ether to form a skin on the outer surfaces of the sheet that prevents the starch granules from causing the sheet to adhere to the rollers (40) upon gelation of the starch. The green sheets are passed between heated rollers (50) to gelatinize the starch granules, and then to dry the sheet by removing a substantial portion of the water by evaporation.