Oil spot refers to the irregular yellow cloud spot on the grey fabric after washing, pre-scheduling and dyeing, some are intermittent straight strips, and some are scattered spots, similar to dyeing defect auxiliary spots and cloth bristles in the shaping paddle. Silicone oil spots are often an abnormal phenomenon that weaving factories and dyeing factories have more disputes.
1. Weaving oil spot
During the weaving process of weft knitted fabrics, the loom must be regularly and quantitatively oiled to maintain lubrication. Especially important parts such as knitting needles, needle grooves and needle tracks are designed to reduce the wear of the machine parts and have good processing performance. For warp knitted fabrics, in the warping process, in order to improve the properties of fiber bundles, smoothness, softness, antistatic and other properties, an oiling device is used to oil the yarn surface.
The purpose is to reduce the friction coefficient between the fiber and the metal yarn guide, protect the surface of the fiber, make it pass through the warp reeds and the yarn guide smoothly, and make the yarn have good weaving performance.
However, the quality, adding amount and adding method of the oil will bring difficulties to the dyeing process. This is because in addition to different oil content, the oil also includes some silicon-containing additives and lubricants with macromolecular structure. If the pretreatment is not clean, it will not only affect the levelness of dyeing, but also coagulate with the oligomers in the dye liquor to form color spots and tar stains that are difficult to remove, called fabric oil spots.
2. Dyeing auxiliaries spot
In the dyeing process or post-treatment of dyeing, selecting suitable dyeing auxiliaries (such as dispersant, leveling agent, softener in bath, defoaming agent, color fixing agent, etc.) can obtain good levelness and improve the hand feeling of fabric , to prevent the wrinkle of the cloth surface, which is beneficial to the smooth running of the fabric in the dyeing vat and the improvement of the color fastness after dyeing.
However, attention should be paid to the compatibility, alkali resistance, acid resistance and the order of addition between the auxiliaries, and the operation should be carried out in strict accordance with the process requirements; otherwise, it is easy to cause dyeing auxiliaries spots.
3. Identify and overcome oil spots
Fabric oil spots and dyeing, setting aid spots are often mixed together, and can only be distinguished when scheduled or completed.
When the cloth is scheduled to fall, if it is a regular yellow straight strip or a yellow spot along the straight line, it should be the oil spot brought by the weaving cloth. If the phenomenon is not serious, it can be cut and washed again with an open width washing machine, which can be significantly improved, or adding 1% anti-yellowing agent to the rolling car of the setting machine will also improve. Serious weaving oil spots should be notified to the customer in time to give feedback to the weaving factory to make adjustments when weaving and refueling.
Auxiliary spots formed during dyeing are relatively easy to confirm when they are formed. Fluorescent spots are easily confused with oil spots on woven fabrics. Cut a piece of sample cloth and light it with a fluorescent lamp under a color light box to distinguish it. it's important for t shirt custom sewing.
Most of the other dyeing auxiliaries spots are hard lumps. When stripping, repairing and reshaping, the lumps will form transparent spandex damage. Some dyes can easily cause yellow spots after dyeing if there are too many fillers. This requires the inspection of incoming dyes to reduce abnormal dyeing.
In addition, when the loom takes up the paper tube in the open width, it should be kept as flat as possible without creases. Warp knitted or weft knitted fabrics are often seen on the production site. Due to the uneven winding of the cloth head, the grey fabric is indented about 10-20m, and irregular spots are formed after dyeing.