PVC foam board is widely used in daily life, PVC foam board manufacturers in the process of processing and production often have a variety of problems, the following we discuss and analyze the common problems of PVC foam board.
PVC foam board outside the slip too much
The precipitation will become serious, manifested in the structure of the mold and the surface of the plate outside the slip of the precipitation will also be manifested in some individual phenomenon on the surface of the plate irregular movement back and forth.
PVC foam board outer slip is not enough
Extruder 5 temperature is not easy to control, easy to heat up, resulting in high temperature of the merging core, the middle of the board out of large bubbles, string bubbles, yellowing and other problems, the surface of the board is not smooth.
Insufficient inner slip of PVC foam board
The plate surface is difficult to control the thickness, manifested as the plate is thick in the middle and thin on both sides; too much internal slip, easy to appear the phenomenon of high temperature of the merging core.
PVC foam board surface yellowing
Reason analysis: barrel, mold temperature is high, lubricant does not match well, the thickness of the board is too thick, yellow issued hot core layer slow heat dissipation, and the stability of the stabilizer also has a relationship.
Solution: Properly reduce the mold temperature, choose efficient lubricant and adjust the lubrication with the thick board to reduce the amount of yellow hair to increase the amount of white hair, choose better thermal stability of the stabilizer.
PVC foam board surface bending
Cause analysis: uneven material flow or cooling is not in place, the factors that cause uneven material flow are generally large traction fluctuations or unbalanced internal and external lubrication in the formula.
Solution: Check whether the cooling water circuit is smooth, so that the board surface is evenly cooled in place, check the traction machine to make its traction speed stable; adjust the amount of lubricant to make the lubrication balance, the current is stable.
Cross-sectional bubble holes or bubble layering
Cause analysis: can be attributed to a point, that is, the melt strength is not enough. Mainly because of excessive foaming agent or foam regulator is not enough, the ratio of the two is not coordinated, or foam regulator quality problems; poor plasticization, low processing temperature, or excessive lubrication.
Solution: Adjust the amount of foam regulator and foam agent, choose the foaming agent with higher melt strength and viscosity; appropriately reduce the amount of PE wax as an external lubricant, and appropriately increase the temperature of the screw barrel to make the plasticization better.
Uneven thickness of PVC foam board surface
Reason analysis: Uneven material discharge
Solution: can adjust the opening degree of mold lip, if the flow rate is too big, can adjust the flow blocking bar, formula adjustment, generally, the inner lubrication is thicker in the middle, the outer lubrication is faster on both sides. Adjust the amount of internal and external lubricant according to the actual situation.
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