PVC crust micro-foam mainly refers to: Seluca method of crust foam, general foam density 0.38-0.8g/cm3, surface hardness can reach Shore 65-82 degrees. And PVC micro-foam: generally refers to the free foaming density 0.38-0.8g/cm3, surface hardness is soft general Shore 35-55 degrees. Celuka method (Celuka) also called controlled foaming method, is currently very widely used, invented by the French gine kulmann company, it is one of the first patented extrusion foam moulding method. The principle of the Seluca method is that the outer skin of the melt is compressed and cooled in the shaping device which is directly connected to the die opening, while the core mould in the cavity ensures that there are spaces inside the extrudate when it leaves the die opening, and that these spaces are filled up by the free foaming of the melt in the shaping mould. The intensity of cooling, the size of the mandrel, and the extrusion speed can influence the density of the foamed core layer and the thickness of the outer crust. Complex shaped profiles produced by this method are characterised by low density, high hardness and smooth surface

The appearance and performance of PVC skinned foam board are very similar to and better than natural wood, and it is known as "synthetic wood". The product has the advantages of moisture-proof, flame retardant, non-toxic, beautiful and strong anti-aging ability. It can be sawed, planed, drilled, nailed, screwed and bonded with woodworking tools, and has processing methods such as thermal bonding and plastic welding that wood does not have. This makes it very widely used. The service life of the product reaches 50 years, which is a new type of decoration and adornment material in line with international standards. It can be used in blinds, bath cabinets, kitchen cabinets, advertisement screen printing, outdoor billboards, signboards, hotels, families, and the interior decoration of ships, automobiles and aeroplanes, giving full play to the function of "replacing wood with plastics", and it is a world-wide green environmental protection product of the twenty-first century.