Five Common problems affecting the quality of PVC foaming Board and their Solutions
1. The surface of the plate is yellowing. The extrusion temperature is too high or the stability is insufficient. The solution is to reduce the processing temperature. If the formula is not improved and the stabilizer and lubricant are added appropriately, the problem can be changed one by one, so that the problem can be quickly identified. Solve problems as quickly as you can.
2. The main reason is that the temperature of the mould is high, the amount of lubricant is also related to the white foaming agent.
3, The plate surface is bent. The material flow is uneven or the cooling is not in place. The factors that cause the uneven material flow are the large traction fluctuation or the uneven lubrication between the inside and outside of the formula, so the machine factors are easily eliminated. Formula adjustment generally external lubrication as little as possible on the premise of adjusting the internal lubrication will have a good effect, while ensuring that the cooling in place.
4,Foaming holes or bubble delamination appear on the cross section. The reason is that the melt strength is not enough, the reason is that the melt strength is not enough. 1. The foaming agent is excessive or the foaming regulator is not enough or the proportion of the two is not in harmony. Or foaming regulator quality 2. Poor plasticization, low processing temperature or excessive lubrication.
5, Uneven plate thickness. Uneven discharge, can be adjusted die lip opening, if the flow rate is too large can adjust the flow bar, formula adjustment, generally more internal lubrication of the intermediate thickness, more external lubrication on both sides of the material faster.