Vietnamese scientists have invented the technology which allows to use leaves, barks and natural materials to dye cotton and silk cloth, which would replace the current dyeing technology using toxic and environment polluting chemical substances.
Recent research works all have pointed out that most of the fabric products available on the market have been dyed or treated with additives, auxiliaries, which can cause allergies, cancer, thus damaging the health or people or even endangering the lives of users.
The latent risks
Textile and dyeing is considered an important industry with high growth rate which has a large production network which can make out diversified products. However, the “green trade” standards have become a big trade barrier for Vietnamese products to reach out to the world market.
With the green standards, garment products have to satisfy the set ecological requirements, must be safe to users’ health and must not be cause the pollution to the environment.
Researchers have found out that 150 colors used for dying now available on the market are azo colors, made of the substances which can cause cancer such as aromatic amine.
According to Dr Hoang Thi Linh, a lecturer of the Hanoi University of Technology, the chemical bond between the dyeing colors and fiber is not a durable bond, which makes out the products with limited color durability. Especially, if mistakes occur during the dyeing process, this would lead to the liberalization of the colors to the environment.
Being able to dissolve in oil, the chemicals would be absorbed through people’s skin. After penetrating bodies, they would be decomposed in the metabolism system, which would result in the establishment of the primitive aromatic amine.
The decomposition process may take place in the intestinal system, on liver or skin surface, thus harming people’s health and endangering the users’ life.
The dyeing industry is now using a big volume of water for its production phases, while it discharges a big volume of waste water, estimated at 12-300 cubic meters of water for every ton of cloth made.
The Environment Treatment Technology Center has found out at the Van Phuc silk weaving village that the indexes of toxic substances are much higher than the allowed levels.
The key to the question
Dr Hoang Thi Linh has invented the technology which allows using leaves, barks and natural materials to dye cotton and silk cloth, which would replace the current dyeing technology using toxic and environment polluting chemical substances.
According to Linh, the materials such as leaves, barks or flowers collected from the wild would be put into an unit next to the dyeing machine, where they would be extracted to get color solutions. After that, the solutions would be poured directly into the dyeing machines to dye cloth as wanted.
Especially, Linh emphasized that the materials are very cheap and easy to be found, including the old tea leaves left at tea farms, a kind of bean available in the south, sapote leaves and almond leaves.
The cloth dyed with natural colors always have pleasant fragrances, which can satisfy many requirements: no azo, no formaldehyde – the substances which can cause cancer and skin allergy. Meanwhile, the technology allows reducing 600 cubic meters of toxic waste water discharged to the environment every year. Besides, the refuse from the production process could be used as fertilizer in agricultural production, thus helping save money and reducing the pollution to the earth.
Source: Lao dong