Common Problems and Solutions in the Process of Casting Film Production

(1) Crystal point

(1) Solution pressure is small, shear force is small, plasticization is poor. The number of layers and the number of filters can be increased appropriately.

(2) It is easy to produce crystalline point after shutdown, and produce different kinds of tape casting film during conversion. For example, when CPP and CPE production are transformed into each other. In this regard, screw and die must be thoroughly cleaned.

(3) Resin is mixed with foreign matter and has high water content. Cleaner production and good preservation of raw materials are essential.

(4) The resin itself is of poor quality and can be exchanged.

(2) Spot of precipitate

Raw materials. Material selection should be appropriate. When there are too many additives, the additives are easy to produce white spots when they have low temperature resistance. If the additives are too few, the smoothness and openness are too poor.

(2) The extrusion temperature is high, the additive is easy to precipitate, and the extrusion temperature is generally lower than 250 C.

(3) The pressure of cleaning roll is too high to press the grain on the film; if the pressure is too low, the precipitated additives can not be carried away slowly and evenly, and the film is taken on the cooling roll.

(4) The smoke extraction ability of vacuum box is poor, and white spot is easy to appear.

_When using the same raw material, the thicker the film is, the more the additive precipitates. In the production of thick films, the raw materials should be changed or the amount of additives should be reduced.

(3) poor smoothness

(1) Extrusion temperature is too high and additives are decomposed.

(2) Low crystallinity of raw materials, such as some copolymers

(3) The temperature of cooling roll is too high.

(4) Large air gap.

(4) Rough surface and poor gloss

(1) The extruder temperature is too low and the plasticization is not good.

(2) The die clearance is too small and the solution is broken.

(3) Cooling roll temperature is too low and extruder mixing is insufficient. It is necessary to reduce traction speed, increase extrusion temperature and screw speed.

(5) Non-uniform transverse thickness

(1) The gap between die and lip is not adjusted properly and needs to be readjusted.

(2) The transverse temperature distribution of die head is not uniform. Check the heater.

(3) There are impurities in the die cavity, which causes logistics disorder and uneven discharge.

(4) The air flow of air knife is not uniform. Check whether the air flow of air knife is stable and balanced.

(5) Excessive or uneven addition of recycled materials. Generally, the dosage is 15% - 20%, and it should be added evenly.

(6) Poor transparency

(1) Low extrusion temperature, poor plasticization and mixing.

(2) The temperature of the cooling roll is too high and the crystallinity of the film is too high.

(3) Shortening air gap and accelerating cooling.The surface of the cooling roll is not clean and should be cleaned.

(7) Striated film

If it is herringbone, the reasons are as follows:

The pressure of air knife is too high.

(2) The cooling of quench roll is not uniform, so it is necessary to remove internal scale.

If the stripe is straight, the reasons are as follows:

(1) Mould lip is damaged and needs to be repaired.

(2) There are sundries in the die, which need to be removed with a copper knife.

(3) There are wounds on the roll surface.

(8) Abrasion

Stable plate, guide roller does not rotate.

(2) There are wounds on the rolls. Pay attention to inspection and repair.

(3) Thin film and electrode collide with thickness measuring head