Common failure examples of composite membranes and their solutions

Common failure examples of composite membranes and their solutions

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The phenomenon of shark skin and fisheye spots in the composite film appears:

1. The temperature of the extruder is improperly set, especially the temperature of the die and the resin is too low, resulting in poor plasticization of the resin, causing a shark skin phenomenon or a fisheye-like stain on the molten resin.

2. The resin contains moisture, which affects the plasticization of the resin.

3. Other resins having different melt indexes or densities are mixed into the resin to make the resin poorly plasticized or incompletely plasticized.

4. When the resin was replaced, the barrel was not thoroughly cleaned, and other resin or impurities remaining in the barrel adversely affected the plasticization of the resin.

Solution:

1. The extrusion temperature of the extruder and the temperature of the resin are adjusted to appropriate values to ensure good plasticization of the resin.

2. The resin is stirred and dried to remove moisture contained therein, so that the resin can be sufficiently plasticized.

3. Replace the resin with the appropriate melt index and density.

4. Thoroughly clean the barrel to remove the effects of impurities.

The composite film has an odor failure:

1. The extruder temperature or the resin temperature is too high, causing the resin to decompose and produce an odor.

2. The air gap is too large, the resin is excessively oxidized, and various oxygen-containing groups having an odor are generated on the surface to cause the composite film to generate an odor.

3. The resin itself has an odor, and the composite film which is extruded and composited therewith also has an odor.

4. The use of a high boiling point, non-volatile solvent in the primer causes some of the solvent to remain, resulting in an odor after the composite film.

Solution:

1. The extrusion temperature is appropriately lowered to prevent decomposition of the resin.

2. Adjust the size of the air gap to an appropriate value.

3. Extrusion compounding is carried out using a low odor resin.

4. Increase the drying temperature of the drying tunnel, increase the amount of blowing, and ensure that the solvent is sufficiently dry. Composite film pattern tensile deformation failure causes:

1. The tension setting and control are improper, and the tension values between the parts are not suitable.

2. The drying tunnel temperature setting is too high.

3. The composite pressure is too large to cause the composite film to stretch.

4. The surface temperature of the cooling steel roll is too high, and the cooling effect of the composite film is poor, and it is easy to cause the stretching phenomenon of the dry roll.

Solution:

1. Check and determine which part of the equipment the stretching phenomenon occurs, adjust the tension value of the section to suit the specific conditions, and match the tension of the other sections.

2. Appropriately reduce the temperature of the drying tunnel.

3. Properly reduce the composite pressure.

4. Reduce and control the surface temperature of the cooled steel roll to make it evenly distributed and have a good cooling effect.

The reason why the composite film sticks to the surface of the cooled steel roll:

1. The surface temperature of the cooling steel roll is too high, and the cooling effect on the molten resin is not good, which affects the cooling, solidification and molding of the composite film, and causes the molten resin to adhere to the surface of the cooling steel roll.

2. The temperature of the molten resin is too high when compounded.

3. The winding tension is too small to peel the composite film from the surface of the cooled steel roll.

Solution:

1. The cooling water temperature is appropriately lowered and the surface temperature of the steel roll is cooled to improve the cooling effect.

2. The resin temperature is appropriately lowered according to the specific conditions, the size of the air gap is adjusted, and the temperature of the molten resin is controlled within an appropriate range.

3. The winding tension is appropriately increased to peel off the composite film from the surface of the cooling steel roll.

The composite film has poor transparency.

1. The extrusion temperature of the extruder is too low, resulting in poor plasticization of the resin, which has an effect on the transparency of the composite film.

2. The surface temperature of the cooling steel roll is too high, and the cooling effect is too poor, so that the transparency of the composite film is greatly reduced.

3. The transparency of the substrate itself is not good.

Solution:

1. According to the performance characteristics of the resin and the actual production conditions, the corresponding extrusion temperature is set and controlled to ensure good plasticization of the resin, which is one of the prerequisites for improving the transparency of the composite film.

2. Appropriately reduce the temperature of the cooling water and cool the surface temperature of the steel roll. Generally, the temperature of the cooling water is controlled to be 20 c or less, and the surface temperature of the cooling steel roll is controlled to be 60 c or less.

3. Replace the substrate with good transparency.