Four methods of identifying true and false indigo yarn

Can an indigo mill cheat? First, we will introduce you to the quality of indigo yarn, which is dyed with natural or synthetic indigo dyes, or can be imprinted with sulfide, VAT or direct dyes. So how can you tell the real indigo yarn from the fake one?

1. Indigo yarn manufacturers will be a drop of concentrated nitric acid on the dyed sample lightly coated, if it is indigo yarn will immediately show white spots, its edge is green.

2. After the dyeing sample is lit on the flame, leave the flame immediately and put in the white porcelain plate. The indigo leaves blue traces on the white porcelain plate due to sublimation under heat, while other dyes do not have this phenomenon.

3. The dyed sample was cut into pieces and placed in a glass test tube, then heated and dried on an alcohol lamp. Indigo vaporizes when heated, with red gas escaping and blue precipitate as it cools in a glass test tube.

4. Dyed samples can be treated with DMF solution cycle. In the case of true indigo yarn, the dye on the sample can be removed completely and become colorless, while the dye of other imitation can not be removed completely.

The true and false identification method summarized by sanmiao Textile indigo yarn factory for us, hoping to reduce the probability that we buy quality false products. You can also visit the manufacturer on the spot. Sanmiao textile will be open to the outside world, and support customers with purchase needs to visit the factory.