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Textile Contamination Removal.

Byline: Hira Mehfooz

The level of contamination decides the quality of yarn and its essential properties such as length, strength, fineness. In this context, contamination can take place during any process, that is from the farm picking to the ginning stage. Contamination, even if it is present in a single component of fiber, causes down grading of yarn, fabric or apparel or even the total rejection of an entire fabric. Therefore, the relationship between growers, ginners, merchants and textile and clothing mills can be jeopardized. This paper focuses on contaminants and its effects on supply chain and outlines preventive measures to eliminate contaminants. This major problem of contamination can be handled by using contamination cleaning methods, especially for Polypropylene.

For example, at Masood Textile Mills in Product Development Department under the guidance of Mr. Shafqat Mehmood (Sr. Manager PD), we have managed a system for the removal of Polypropylene as a contaminant from the cotton/ polyester (Coolmax) / Lycra blended fabric (White) by using an Organic Solvent without affecting the fabric properties.

Contamination

Contamination basically is a presence of extraneous, materials, that renders a substance or preparation impure or harmful in the same way mixing of any irrelevant Component or material with main product at any level of collection, production, handling, storage, processing in the yarn manufacturing process. Classifications of contaminants as shown in the fig.1.

Causes of Contamination Textile

The following are the some of the reasons behind high contamination during process in textile.

1. Hand picking method of fibers.

2. Usage of fertilizer bags (cloudy).

3. Improper working methods.

4. Packing of fibers not in balanced way.

5. Wrong codification after packing process.

Effects of contamination

1. It causes wastage of dyeing materials and requires extra efforts at cleaning process that inflates cost.

2. The quality and value is still affected even after cleaning leftover embedded pieces of contamination in yarn.

3. Fabric appearance produced with contaminated yarn will be poor and prone to rejection.(See fig.2)

1. Dyeing affinity of contamination is different from dyeing affinity of fabric, which leads to uneven fabric coloration. As shown in fig.3. (Polypropylene remain undyed)

Removal of Polypropylene from the knitted fabrics

The process for the removal of Polypropylene from the knitted fabric is explained as under:

Fabric Specification: The Fabric containing Polypropylene contamination: Bleached (White).

Contents: 56/38/6 Cotton / Polyester (Coolmax) / Lycra

Effects of Polypropylene on the white fabric:

Red, green spots on white fabric as polypropylene itself has different colors. The polypropylene cannot be dyed with common methods, due of its high crystallinity and non-polar aliphatic structure, which does not contain any reactive site to react with dye molecules. Therefore, the contaminated area will remain undyed, here Masood Textile Mills has developed the need to remove or dissolve that portion from the white fabric.

Apparatus and material required include contaminated fabric, water, detergent for washing and organic solvent. (1,1,2,2 Tetrachloroethane C2H2Cl4)

Procedure

1. Take contaminated fabric sample (bleached knitted) containing spots of Polypropylene and make solution of 1,1,2,2 Tetrachloroethane as: 70% Water, 30% 1,1,2,2 Tetrachloroethane.

3. Run the machine at 80degC for 20 minutes and upon completion of the specified time, wait for a while in order to cool the fabric. Afterwards rinse and dry the fabric.

6. The analysis of the fabric shows that polypropylene was totally removed, as there are no spots on the treated fabrics.

7. The treated fabric contains the toxicity of 1,1,2,2 Tetrachloroethane and this amount of Tetrachloroethane determined in the fabric by gas chromatography was as under:

Sample Description 1,1,2,2 Tetrachloroethane (%)

Bleach knitted fabric 2.1

9. In this context, Masood has adopted a process for the removal of tetrachloroethane without using any organic solvent. The emulsification technique was employed in order to make process more feasible and less toxic.

10. The different wetting/emulsifying agents were selected to remove 1,1,2,2 Tetrachloroethane from the fabric. The fabric was treated with different aqueous concentrations of selected wetting agents under different treatment conditions. The residual 1,1,2,2 Tetrachloroethane after treatment was re-evaluated by gas chromatographic technique.

The treatment details and results are tabulated as shown in this table:

###Phosphate###Rucogen WBL###Felosan RG-N

Wetting Agents###Detergent/###(Rudolf GmbH) (CHT GmbH)

###wetting agent

Wetting agent used (%)###3###0.4###3

Running Temp.(degC)###60###60###60

Running Time (mm)###30###30###30

Washing cycles###1###1###1

Tetrachloroethane conc. after###Not detected###0.6###Not detectcd

Treatment

Conclusion

The above observations show that Tetrachloroethane is present in the treated fabric in objectionable amount i.e. 2.1% by weight of the fabric. The proper treatment of the fabric is required prior to further processing or finishing. Therefore, the best washing treatment results were obtained by using phosphate detergent/wetting agent (laboratory developed) and Felosan RG-N by using the ratio of 3% at 60oC followed by water rinsing.

Dep. Research And Development, Masood Textile Mills.
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Author:Mehfooz, Hira
Publication:Pakistan Textile Journal
Geographic Code:9PAKI
Date:Feb 29, 2012
Words:831
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