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 yarns. 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 made by mixing and melting granules of pigment and polypropylene chips. The uniformity of mixing and the 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 technician.

(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 the uniformity of mixing and the concentration of the diluted masterbatch. The measures taken are that when several masterbatch species are required and the low concentration is added to the masterbatch, the masterbatch is reconstituted by:

The original masterbatch and the polypropylene chips are uniformly mixed in proportion, and are mixed and cooled by a granulator, cooled, and pelletized to form a reconstituted masterbatch. When used for spinning, the color difference is obviously improved, but sometimes there are pieces. 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. When the post-processing is twisted, the yarn on the yarn must be checked after the color batch number is checked.

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

1. The operator will inspect the inspection on time, do a good job record, and check the process parameters at any time, find that the process parameters exceed the standard and the equipment is abnormal, contact the technical personnel 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) Polypropylene BCF yarns 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 different twisting degree, 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 standard is exceeded, the equipment will be repaired.

2. The vehicle guards can inspect at any time and find that the forming is poor, the elastic is tight, the process components are not smooth and deviate 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 in the marking and area storage of the yarn car to prevent mixing batches during the setting.

(7) Filament 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.