Chromatic aberration refers to the color difference that can be seen by the naked eye during the inspection and use of the same batch of Polypropylene BCF yarn. Includes color variations between segments and segments, between barrels and between layers.

Polypropylene BCF yarn, process and control method for producing chromatic aberration during spinning

(1) Do a good job in screening the masterbatch

The masterbatch for spinning is obtained by mixing and melting granules of pigment and polypropylene chips, and the uniformity of mixing and uniformity of particle size affect the uniformity of the spinning masterbatch into the system. To this end, the incoming masterbatch should be visually inspected and tested for spinning to ensure that the masterbatch quality meets the requirements. The masterbatch of our factory is inspected and tested by the workshop technicians.

(2) Granulation is strictly carried out according to the process

The workshop first considers the unevenness of the metering system. However, considering the direct use of a single high-concentration masterbatch, this problem has not been found. Therefore, it is inferred that several kinds of masterbatch may be used together with uneven mixing. For the masterbatch with less added amount, the masterbatch The particle size is constant, and the smaller the amount added, the larger the error, and finally the chromatic aberration occurs in the filament. Therefore, the key to the problem is to mix the uniform and dilute masterbatch concentration. The measures taken are to use several masterbatch color combinations and low concentration to add masterbatch. Masterbatch reconstruction is carried out by:

The original masterbatch and the polypropylene chips are uniformly mixed in proportion, and are mixed, cooled, and pelletized by a granulator to form a reconstituted masterbatch. When used for spinning, the color difference is obviously improved, but sometimes there is a piece. Color difference. Further analysis of the reasons may be that the masterbatch and the slice have different specific gravity, the masterbatch ratio is significant, the proportion of the mixture falling into the initial stage is slightly higher, and the density of the re-injection into the extruder is higher and lower, and the reconstructed masterbatch has a color difference before and after.

(3) Metrology system regularly checks calibration and weighing sensor linear inspection

The stability of the metering system will play a crucial role in the generation of chromatic aberration. If the weighing error of the metering system is large, the masterbatch ratio of the extruder will be inaccurate, and a serious large amount of chromatic aberration will occur. How to maintain the metering system?

1. The metering system alarms and stops immediately. After the isolation of the filaments for ten minutes before and after, the next step can be entered.

2. Regularly correct the metering system.

(4) Strengthen production control of similar colors

1. When arranging the production plan, the similar colors should not be produced at the same time and continuous production, to prevent mixed batches and mixed bags.

2. If the similar colors must be produced at the same time, the identification and isolation areas should be stored, and separate post-processing and packaging should be carried out.

3. In the post-processing and twisting, the yarn on the yarn should be checked after the color batch number is checked.

(5) Do a good job in quality control of spinning process

1. The operator will patrol on time, do a good job record, check the process list at any time, find out that the process parameters exceed the standard and the equipment is abnormal, contact the technicians in time, and do product isolation and traceability.

2. Deal with the problem of poor suction in time to avoid discoloration caused by poor suction.

3. Check the problem of the winding of the drafting roller at any time, and find that the wrapped wire is cleaned in time, especially when the head is raised, and the drafting roller is cleaned to prevent the light color difference caused by the uneven heating of the spinning.

(6) Color difference control during the process of twisting

After different twisting and setting tests of the same color yarn, we found that the same color and twist are different. After the setting, the color appears color difference, so it is very important to do the twisting machine monitoring.

1. Use the flash speedometer to monitor the spindle speed every day. The deviation is controlled within 5%. If the limit is exceeded, the equipment personnel should be repaired.

2. The vehicle operator checks at any time and finds that the forming is poor, the elastic is tight, the process components are not smooth and deviated from the original position, and it is necessary to stop the treatment in time, or to find the repair machine, and the yarn is isolated and inspected.

3. After the twisting, do a good job of marking and area storage of the yarn car to prevent mixing and batching.

(7) Filament shaping and color difference control

1. The setting temperature is set at 148-152 °C, and the temperature should not be too high. Otherwise, some filaments will change color when exposed to high temperature.

2. The residence time of the setting chamber is controlled within 2 minutes, and some filaments will change color when the oven is long.

3, the pressure is controlled at 1.2-1.5bar, the pressure directly affects the temperature change of the setting chamber, which will cause color change.

The above is the seven major processes of Polypropylene BCF yarn color difference control.