ACR-type processing aids have the effects of promoting the melting of PVC, improving the surface finish, improving the elasticity of the melt, and enhancing the elongation and strength of the melt. It is also conducive to covering air bubbles and preventing the collapse of cells. The molecular weight and dosage of the foaming regulator have a great impact on the density of the foamed sheet: as the molecular weight increases, the melt strength of PVC will also increase, and the density of the foamed sheet can be made lower, and the regulator can be increased. The amount has the same effect. However, this effect does not have a linear relationship. Continued increase in molecular weight or increase in usage does not have a significant effect on reducing density, and the density will gradually become constant. Note that the viscosity of the resin used should not be too high. In order to facilitate the dispersion and expansion of the bubbles, the pressure of the entire cross-section of the sheet must be coordinated, which requires high melt fluidity.
Kanban surface, if it is a high-quality PVC foam board, the mechanical texture is not obvious, the surface color is no color difference, milky white, the surface is also no stains, no obvious small pits, no pinholes, no coarse holes, no cracks. Note: The discarded non-milk white foam board is not an environmentally friendly board, and the environmentally friendly board does not contain lead (the content is less than European and American standards). If you touch the PVC foam board with your hand, if it feels smooth and flat, it means that it is of high quality. The incisions on the side of the board should be flat, with fine pores, no coarse perforations, no pinholes, no bees, no serious powder loss, and the open fibers will fall off without bouncing. Note: If the above situation occurs, you need to pay attention to it, and the subsequent process of finished product is troublesome.
