Sudden Problems and Prevention of High Temperature and High Pressure Dyeing

1. Elements of sudden problems:

①The frequent sudden problems of high temperature and high pressure dyeing usually come from the following aspects:

Equipment. Sudden damage to a certain part of the dyeing machine, such as electric motor, surface, safety wire, water pump, valve, pipeline, transmission belt, bearing, lifting turntable, etc.

②Technical operation. The joints of grey fabrics are not well sewn, and the joints are suddenly torn during work; if the fabric is not carefully fed, twisted, and knotted during work, causing blockage; The knot causes the blockage; during operation, the nozzle pressure is not adjusted properly and the fabric is blocked.

③ External elements. Sudden power failure and sudden stop of equipment work; sudden stop of steam to reduce dyeing temperature; sudden water cut off and interruption of cooling water of circulating pump and forced shutdown; poor quality of defoamer, too low defoaming power, dye bath Too much foam leads to air suction halfway through and fabric blockage occurs.

2. Compensation and disposal after the problem

During different dyeing temperatures, the effect of the failure on the fabric is different, so the treatment methods are also different.

①Dyeing temperature does not reach 100℃. There is no pressure increase during this period. If a fault occurs, the result is usually not severe, and the treatment is relatively simple. After the fault is eliminated, the temperature can be re-heated and dyed from 60 °C according to the original technology. Because the dyeing temperature is below 100 ℃, the bulking of polyester is not sufficient, and the disperse dyes have not been dyed much, so the problems such as color pattern appearance and wrinkles will not be obvious. However, in order to prevent this, when the heat preservation period of 130 °C is reached, the time of heat preservation and dyeing can be appropriately extended to make stability compensation. In this way, the dyeing results are usually comparatively satisfactory.

②The dyeing temperature is between 100 and 130℃. When the dyeing temperature is in the range of 100-130℃, because the pressure in the dyeing machine has been boosted, the first thing to do is to pay attention to safety. During this period, because the puffing of polyester is rapidly accelerated, and the dyeing speed of the dye is also greatly increased, so during this period, if a problem occurs and is forced to stop, color flowers and stains will be unavoidable. If it is not a major incident and the disposal time is not too long, high temperature leveling agent and extended heat preservation time can be added as appropriate; if the incident disposal time is long and the fabric stays in the dyeing machine for too long, the high temperature carrier method must be used to strengthen the disposal; If the doubt is more serious, the high temperature carrier method can be repeated again.

③ 130 ℃ insulation dyeing period. There was a problem during the dyeing of this article at 130°C. When reducing the pressure and cooling down to deal with the accidental re-dyeing, the previous heat preservation time should be discarded, and the technical rules should be re-complied with and the heat preservation time should be appropriately extended to ensure stable compensation. During this period, the adsorption of disperse dyes has been relatively sufficient, so the risk of defects is greater than that during the 100 ℃ period, but less than the boost period of 100-130 ℃. However, if the fabric is blocked and stops, or stays in the dyeing machine for a long time, the high-temperature leveling agent 0.5-1g/L should be added during heavy dyeing, and then the heat preservation time should be extended appropriately. This can not only promote and strengthen the transfer of dyes, but also help to overcome wrinkles.

If the steam supply of the boiler is suddenly stopped during the dyeing process, the dyeing machine should be allowed to continue to work. This idle time is regarded as invalid work, and the effective time of dyeing will be calculated after the normal steam supply is restored.

Regarding the compensated fabric, special inspection should be done immediately after dehydration. If there are still doubts and the high temperature carrier method has been adopted to strengthen the correction method, it is necessary to consider the stripping treatment for re-dyeing.