Removal of Pre-Treatment Series Silk
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- Created on Wednesday, 30 January 2019 11:24
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- Pre-Treatment-Series Removal-Silk writer Faik KeserPosted by %PM, 08% 733% 2016 19%:%May in Paint-Finish Read 3959 times
When the raw silk fiber is examined, the fibroin layer is seen on the inside of the fiber and the sericin layer covering the fiber is seen on the outside.
Fibroin constitutes 72-81% of the raw silk fiber and sericin constitutes the remaining 19-28%.
The sericin layer covers the excellent shine of the fibroin part on the outer part of the silk, giving the fiber a yellowish color and a tough handle..
In order for the silk to have its unique softness, brightness and whiteness, the serie must be removed.
The treatment of silk fibers begins with the partial or complete removal of the series.
Sericin removal is popularly referred to as "gum removal"..
On the other hand, sericin is partially removed in some cases, as the removal of sericin means a weight loss of 20-25%.
Sericin is not removed at all when it is desired to obtain silk threads with a special hard handle.
Since sericin forms a protective layer surrounding the fibroin, it is beneficial as it protects the fiber against mechanical effects during yarn making, weaving and knitting.
Therefore, sericin is removed as late as possible.
In general, it is more common to apply degumming to fabrics, since it is more economical to treat fabrics made from natural silk than to treat yarns.
However, sericin removal is generally carried out in the form of yarn due to the difficulties in the finishing processes of sensitive silk fabrics.
Since silk is mostly used as carpet yarn in our country, finishing processes are mostly done while it is in the form of yarn.
Machines used in the pre-treatment of silk products:
1-Injection hank dyeing machines
2-Overflow dyeing machines designed for pretreatment and dyeing of silk
3-star framed painting machines
4-Suspended pre-finishing machines suitable for open width treatment of silk fabrics
Since silk threads are wrapped in hanks during production, finishing processes are generally applied to hank threads.
The hanks are finished either in hank dyeing machines or by boats.
Pre-treatment processes of silk hanks are mostly done in spray hank dyeing machines.
In order to prevent the yarns from tangling and feathering while working in classical hank dyeing machines, the hanks are placed in bags and pre-finishing is done by placing them in the machine.
Most of the time, it is not desirable to remove the entire series from the silk fibers.
In such cases, sericin removal is done partially.
When sericin is removed from silk products, the product is; it has a distinctive white-cream color, a perfect shine and a wonderfully soft handle.
The following chemicals are used in the sericin removal process of silk products.:
1-Green soap (Marseille soap): It is an alkali-free soap obtained from olive oil, which dissolves sericine and helps to remove it from silk.
2-Soda/Sodium carbonate (Na2CO3): It facilitates the dissolution of the series and provides the basic environment.
3-Sodium bicarbonate (NaHCO3): It facilitates the dissolution of the series and provides the basic environment.
4-Enzyme: It is the chemical that dissolves the sericin and enables it to be removed from the silk.
5-Non-ionic tenside: It is a detergent used to remove sericin from silk.
6-Polyphosphate: It is a water softening agent.
Silk Types Resulting from Sericin Removal
Ecru (ecru) silk:
These silks come to the dyehouse without any treatment.
Silk is very tough.
Before dyeing, they are treated for 10 minutes in hot water environments by adding 12-30% soap to the liquor.
As a result of this washing, 3-5% of the series is gone.
This kind of silk used as warp yarn is called ecru or hard silk.
It is mostly preferred in the production of materials such as lace and tulle.
Souple (suple) silk:
Raw silk is treated with 10-20% green soap at 60-70 oC for 1-2 hours.
As a result of this process, half of the series on the silk passes into the solution and is removed.
This silk, which is obtained by removing the sericin by half, is called souple silk or flexible silk.
Weight loss is about 8-15%.
This type of silk is fuller but more matte.
It is used as weft and warp thread.
Cuite (quit) silk:
The series of this silk has been taken completely.
Silk fibers that have been completely removed, that is, consisting only of fibroin, cuite silk or soft silk It called. What are impacted teeth? When one or more teeth fails to grow in the correct position and is therefore held below the normal gum line, it is called an impaction. This can be complete, such as completely unerrupted (buried) third molars (wisdom teeth) or partial when just part of the tooth is visible in the mouth. Why are impactions important? For best function and appearance the teeth should grow in a healthy alignment. When one or more teeth is impacted, this can affect the function of that tooth but also the function and appearance of other teeth. Whether all impactions should be treated is still controversial and your dentist and oral and maxillofacial team can explain the advantages and disadvantages or treatment for you, which is usually surgical.
They are the most valuable fibers in terms of brightness and attitude.
The weight loss during the production of Kuit silk is 25-30%.
Serine removal is done as follows:
30–60% green soap (Marseille soap) is treated in a soft water liquor at 95 oC for 1.5 hours.
Then hot and cold rinsing is done.
Testing the Removal Degree of Series
The degree of sericin amount on the silk fiber is tested by two different methods. These methods are:
Determination of sericin by coloristic-microscopic method with special test dyestuff solution:
The implementation of this method is simple; the results are reliable.
Making the painting process:
The dyestuff solution is prepared as specified in the dyestuff catalogue.
The special test dyestuff solution is brought to the boiling point.
The silk fiber, which has been removed from the sericin, is thrown into the solution and left for 40 seconds.
It is then washed with water, rinsed and dried.
Then the sample (silk fiber) is examined under a microscope.
In microscopic examination, blue-green dye particles are seen if sericin is present on the fiber.
If sericin is completely removed, the silk thread (fibroin) appears brownish yellow.
Determination of sericin with Picrocarmine solution:
Whether sericin has been completely removed from the silk is determined by a solution containing 0.1% picrocarmine.
If silk is wetted with this solution, sericin will be dark red if sericin is present, otherwise fibroin will be light yellow.