9 common problems in fabric softening and finishing

Update:10 Aug 2020
Summary:

1 Can't reach the feel The soft style of soft finishing […]

1 Can't reach the feel

The soft style of soft finishing varies with different customer requirements, such as soft, smooth, fluffy, soft waxy, oily, dry and slippery, etc. Different softeners are selected according to different styles. Among the films, there are softener films with different structures, and their softness, bulkiness, smoothness, yellowing, and effects on fabric water absorption are different. Among the silicone oils, the properties of modified silicone oils of different modified genes are also different, such as amino silicone oil, hydroxy silicone oil, epoxy modified silicone oil, carboxyl modified silicone oil, and so on.

2 colors turn yellow

Among the films, the cationic film has good softness, good hand feeling, easy to be adsorbed on the fabric, yellowing and discoloration, affecting the hydrophilicity. Amino silicone oil is currently the most widely used silicone oil, and amino will cause discoloration and yellowing. In emulsion polymerization, cationic surfactants such as 1227, 1831, and 1631 are sometimes used as emulsifiers. These emulsifiers can also cause yellowing. When silicone oil is emulsified, the emulsifier is different, and its "peeling effect" is different, which will cause peeling and light color under different conditions, which is already a color change.

3 The hydrophilicity of the fabric decreases

Generally, problems with the structure of the film used and the lack of water absorption genes after the silicone oil film is formed, and the blocking of water absorption centers such as the hydroxyl groups of cellulose fibers, the carboxyl groups and amino groups on the wool, etc., cause the water absorption to decrease.

Treatment method: Anionic, non-ionic film and hydrophilic silicone oil should be used as much as possible.

4 dark spots

Causes: ① The oil stains on the fabric were not cleaned during pretreatment, and the oil stains were darker during dyeing. ②There is too much foam in the dyeing bath, and the mixture of foam, floral sweater, dye, etc. sticks to the fabric. ③Dark oil spots caused by floating oil of defoamer. ④The tar in the dyeing vat sticks to the fabric. ⑤Dye agglomerates to form dark spots under different conditions. ⑥ Excessive calcium and magnesium ions in the water combine with dyes and stick to fabrics.

Treatment method: ①Add degreaser during pretreatment for scouring. ②The dyeing auxiliaries adopt low-foaming and non-foaming auxiliaries. ③Select the defoamer that is not easy to float, add a chelating agent to improve water quality, and add a dispersant to prevent dye aggregation. Use the cleaning agent to clean the tank in time.

5 light spots

Causes: ①The pretreatment is uneven, and the hair effect of some parts is not good, resulting in a certain degree of repellency, with repellent substances. Calcium soap, magnesium soap, etc. or uneven mercerization on the cloth during pretreatment. ②Uneven drying of semi-products. ③The cloth surface is stained with undissolved sodium sulfate, soda ash and other solids. ④Drip water before drying the dyed material. ⑤Auxiliary stains during finishing of dyed fabrics such as softening.

Treatment method: Strengthen the pre-treatment. When selecting the pre-treatment auxiliaries, it is not easy to form calcium magnesium soap, and the pre-treatment must be uniform and thorough (this is related to the selection of scouring agent, penetrant, chelating dispersant, mercerizing penetrant, etc.). Sodium sulfate, soda ash, etc. must be put into the tank well and production management must be strengthened.

6 alkaline spots

Cause: After pre-treatment (such as bleaching, mercerizing), the alkali removal is not clean or uneven, causing alkali spots.

Treatment method: The alkali removal process of the pre-treatment process must be strengthened.

7 Softener stains

Cause: The soft sheeting material is not good enough, and there is a block softener adhering to the fabric. There is too much foam after the soft sheet is formed. When the cloth comes out of the cylinder, the cloth will be stained with softener foam. The water quality is poor, the hardness is too high, and the impurities in the water combine with the softener and agglomerate on the fabric. The cloth surface has anionic substances, which can be combined with cationic softeners during soft processing to form stains, or the cloth surface has alkalis to make the softeners agglomerate. The structure of the softener is different, and some of the softener changes from an emulsified state to a scum stick to the fabric at a higher temperature. The original tar-like softener and other substances in the tank fall off and stick to the fabric.

8 Silicone oil stains

Cause: The pH value of the cloth surface is not neutral, especially with alkali, causing silicone oil to break and float. The water quality of the treatment bath is too poor and the hardness is too high. Silicone oil is very easy to float in water with a hardness of >150PPM. Silicone oil quality problems include poor emulsification (poor choice of emulsifier, poor emulsification process, too large emulsified particles, etc.) and inability to withstand shear. Choose a silicone oil that is resistant to shear, electrolyte, and pH changes, but pay attention to the way the silicone oil is used and the environment, and you can also consider choosing a hydrophilic silicone oil.

9 Poor fuzz

Poor raising is closely related to the operation of the raising machine (such as tension control, raising roller speed, etc.). When applying softener (commonly known as waxing), controlling the dynamic and static friction coefficient of the fabric is the key, so the preparation of the fluff softener is the key. If the softener is not used well, it will directly cause poor fluff.

 

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