1. Stability is not enough, will affect the entire surface,yellow plate, the frangibility of PVC foam board is very high.
2. PVC foam board deficiency of whiteness
The white foam agent is very important, ordinary white foam agent is used to balance the foam structure, and a series of B8 foaming agent not only has the effect of general equilibrium absorption white foam agent, but also has the whitening role of icing on the cake, make the surface brightness whiteness upgrades.
3. Melt strength deficiency will lead to foam sheet foam big hole and vertical section long hole.
The most direct way to judge whether the melt strength is insufficient is to press the plate which is just off the mould. If the press is very difficult to bounce, that poor melt strength
4. Lubricating Agent
Internal lubrication, the amount of external lubrication to add more or less, will directly affect the quality of PVC foam board.
5. Technology temperature control problem
Control process temperature: improve the processing temperature, the material will reduce the stability time, stability problem; lubrication balance of the original will be broken, the general performance is lack of lubrication, especially at the late stage of lubrication, need to improve the amount of external lubrication; temperature will lead to improved melt strength reduced, foam sheet foam increases. The foam sheet to reduce the number of brittle fracture; the temperature decreased with increasing melt strength will reduce melt viscosity, viscosity reducing shear dispersing ability, strong ability of screw is not dispersed, sometimes uneven dispersion.