Oil spots, regardless of color, can only be discovered after dyeing or direct production and processing into knitwear. Could knitters and finishers be able to detect these oil spots before they are dyed or processed? Research is already underway, in various research projects, on methods to detect and prevent oil stains in textiles.
Speckles on knitted fabrics are caused by needle oil inevitably being left on the textile during the knitting process, but these oil stains cannot be completely removed during the pretreatment process. Whether oil stains can be effectively cleaned is affected by many factors, which makes pre-treating textiles even more difficult. Generally speaking, uneven dyeing will occur because the needle oil on the fabric will affect the fiber’s effective absorption of dye. Therefore, there are often some elongated or blocky patterns in the entire package of fabrics.
At the Institute for Automated Production at the Federal Institute of Technology in Zurich, Switzerland, researchers used a “process-oriented analysis” method to describe oil spots. It is a method of graphical analysis by which any system can be fully represented and studied. Here the entire process is described by drawing a flow chart.
In the diagrammatic analysis approach, they viewed the knitted fabric production process as a system. This system requires clear definitions, and in order to simplify the problem, it is also required to replace each process with a consecutive number. These definitions and numbers are then integrated and represented in the flow diagram. Through this method, they can find various factors that cause oil spots. Moreover, different processes can be described in detail at each level.
For example, through the flow chart, you can find ways to prevent oil spots, including all elements including fabric finishing.
Looking for traces of oil spots
The definition of oil spots here is: the needle oil is left on the gray cloth to form a pollutant. When the gray cloth is dyed and processed into finished fabric, the stain becomes unable to absorb the dye. became a flaw. A variety of methods for detecting oil stains on textiles have been developed. Here, we can use oil red to detect oil spots. Because after coloring, the area with needle oil will appear darker than the clean area next to it, so this method can be used to detect oil stains on the gray fabric.
The different wettability of cotton fabrics with and without oil stains can also be used to successfully detect oil spots. The results show that a drop of needle oil (assuming it can be mixed with water) can enhance the wettability of cotton gray fabric. Because the area contaminated by oil droplets absorbs water completely, the oil spots will be visible.
For the detection of oil spots on dyed finished fabrics, an appropriate surface image method can be used. By studying the changes in the surface structure of the polystyrene film, we found that the surface layer of the polystyrene film will change with changes in pressure and heat. Therefore, we can easily identify the oil stain when it reacts to the film.
Another new detection method is to use a piece of oil test paper. This is a water-resistant test strip whose color changes due to exposure to different hydrocarbonschanges due to the compound. This method is similar to the surface image method described above, which uses the test paper’s response to pressure and heat to identify oil spots. Although this method can also be used to detect oil spots on finished fabrics after dyeing, the detection effect is not as obvious as the above-mentioned method using styrene film.
At present, a variety of methods for detecting oil spots have been developed, including:
– During the dry cleaning process, the reaction between the film and the compound is used to detect oil spots;
– In the indicator light Oil stains can be found directly under the microscope;
-Gas chromatography analysis;
-Use ultraviolet indicators to detect oil spots.
These methods have been used to detect and evaluate oil spots on a wide variety of gray and finished fabrics. What is important here is the detection clarity, the ability to detect gray fabrics and finished fabrics at the same time, and the actual operation to be simple and convenient. In addition, the emulsifiable and washable properties of needle oils were also studied.
Looking forward to further research
Further research work is continuing, and oil stain pollution on knitting machines will eventually become a thing of the past. This article will play an important foundational role in later research work. Faiss-Textil and the Albstadt-Sigmaringen Academy are eager to find partners from the textile industry who are willing to contribute their knowledge and jointly discuss ways to solve problems.
How to prevent the occurrence of oil spots?
There are currently many ways to prevent or remove them. Here are a few key points:
– Develop a more suitable oil
– Consider the lubrication characteristics of the knitting machine when it is working
– Enhance the washability of oil
– Combine it with environmental protection
– Improve the lubrication system
– Maintain the knitting machine in a timely manner as needed
– Adjust the oil stain washing process
– Strengthen quality monitoring at each production stage to prevent the occurrence of oil spots.
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