PVC foam board has the properties of flame retardant, self-extinguishing, heat insulation, muffling, sound dissipation, vibration resistance, etc. It also has the advantages of steam-proof, dust-proof, water-proof, rust-proof, acid, alkali, salt and other chemical corrosion. What are the problems of PVC foam board in actual use? The following PVC foam board manufacturer Gege technician to answer you in detail.
PVC foam board is a PVC industry products in the formula is difficult to adjust, but also easy to have problems with the products. Because of its larger and heavier mold, it causes a lot of inconvenience to the quality adjustment, plus the product foaming, sometimes it is difficult to control and adjust the problem.
Common problems in the use of PVC foam board.
Problem 1: Yellowing of the board surface
Cause: Extrusion temperature is too high or stability is not enough.
Solution: Reduce the processing temperature, if no improvement can be seen to adjust the formula to increase stability, appropriate increase in stabilizer and lubricant, can be changed one by one, first increase the stabilizer to see the effect, and then adjust the lubrication, so that the lubrication balance, so that it is easy to quickly identify the problem, fast speed to solve the problem.
Problem 2: Board surface bending
Cause: uneven material flow or cooling is not in place.
Solution: The factors that cause uneven material flow are generally large traction fluctuations or uneven lubrication inside and outside the formula, the machine factors are easy to exclude, the formula is generally adjusted under the premise of external lubrication as little as possible to adjust the internal lubrication will have good results, while ensuring that the cooling is uniformly in place.
Problem three: the cross-sectional surface of the bubble hole or bubble layering
Causes: can be attributed to a point, that is, the melt strength is not enough, the reasons for the melt strength is not enough 1, too much blowing agent or foam regulator is not enough or the ratio of the two is not coordinated, or foam regulator quality problems 2, poor plasticization, low processing temperature or excessive lubrication
Solution: Firstly, reduce the amount of foaming agent appropriately to see how the effect, if the effect is not large enough to add the right amount of regulator or melt strength regulator; secondly, if the plasticization is poorly caused by the processing temperature can be increased or the amount of lubricant is reduced appropriately.
Problem 4: yellowing in the middle of the plate
Causes: the first barrel core temperature mold temperature is high, the second lubricant dosage is unreasonable, and again with the white foaming agent has a certain relationship.
Solutions: appropriate to reduce the mold temperature, screw temperature adjustment; appropriate to increase the internal lubrication; add an appropriate amount of white heat-absorbing foaming agent to absorb the excess heat released by the decomposition process of the foaming agent AC.
Problem 5: Uneven thickness of the board
Cause: Uneven material discharge
Solution: can adjust the mold lip opening, if the flow rate is too large can be adjusted to block the flow bar; formula adjustment, if the middle thick, both sides thin, indicating that the melt fluidity is relatively poor, can be appropriate to improve the internal lubrication, especially the amount of 316 type, or appropriate to reduce the external lubrication; on the contrary, if the two sides thick, the middle thin, the direction of adjustment will also be opposite.