Foaming biodegradable lunch box with polylactic acid on inner layer and starch paper pulp on outer layer and preparation method of foaming biodegradable lunch box

The invention provides a meal box preparation method of an inner layer heat-resistant polylactic acid composite outer layer starch paper pulp foaming material, the inner layer is prepared by mixing polylactic acid, poly (butylene succinate), talcum powder, a nucleating agent and a lubricant, melting, blending and extruding to obtain polylactic acid modified resin, then extruding to obtain a sheet, and carrying out plastic molding and cutting to obtain an inner layer meal box; the outer layer is prepared by mixing starch, paper pulp fiber, ground calcium carbonate and a plasticizer in proportion, melting and blending by using a kneading internal mixer, extruding by using an extruder to obtain a modified starch paper pulp blend, putting the obtained modified starch paper pulp blend into a molding press with a set temperature, and carrying out mold pressing foaming to obtain the outer layer starch paper pulp foamed meal box; the prepared inner-layer polylactic acid meal box and the prepared outer-layer starch pa