How to reduce the density and specific gravity of marbled melamine paper?

How to reduce the density and specific gravity of marbled melamine paper? According to the current technology of domestic manufacturers, stone paper can already make the appearance and texture of traditional paper, but most of the marbled melamine paper cannot reach the density and specific gravity of traditional paper. 1) Starting from raw materials As we all know, the main components of stone paper are thermoplastic resin and calcium carbonate fine powder. The choice of the two materials is closely related to the density and specific gravity of stone paper. Calcium carbonate, accounting for about 70-80%, is divided into light calcium carbonate and heavy calcium carbonate. The real density of light calcium is 2.4~2.6g/cm3, and the real density of heavy calcium is 2.6~2.9g/cm3. It is made by chemical method, and heavy calcium is mainly obtained by mechanical crushing, grinding and sorting. It can be seen that choosing light calcium carbonate is more conducive to the reduction of density, but light calcium carbonate requires more processing procedures. The cost is higher than that of calcium. Thermoplastic resin, accounting for about 20-30%, mainly polyethylene and polypropylene, polyethylene is divided into, low density polyethylene (LDPE) has a small density (0.910~0.925), light weight, flexibility, low temperature resistance One, resistance Good impact resistance. High density polyethylene (HDPE) has a high density (0.941~0.965}, has a higher operating temperature, and has better hardness, mechanical strength and chemical resistance. Choosing low density polyethylene is more conducive to reducing the density. 2) Starting from the production process, the production process of stone paper includes calendering method, casting method, blown film method and biaxial stretching method. The biaxial stretching method cannot be produced in China at present, and only a few countries can produce it. To greatly reduce the density of stone paper, but the equipment is expensive, usually more than 100 million yuan, but the quality of the product is good. 3) Starting from foaming is a very common technology in the plastics industry, and it is currently on the market. Mainly based on chemical foaming. Chemical foaming is an industrial problem in the extrusion process, especially in such thin film products.