Authors Srivastava, A. and Singh, T.G
The consumers, the world over have realized the importance of eco-friendly, biodegradable natural dyes which are being encouraged and preferred by everyone. Natural dyes have no health hazards or disposal problems but on the contrary act as a health care. Benefits of using natural dyes and finishes for textiles can be numerous. In its preparation and application, no or only mild chemical reactions are involved which are unsophisticated and harmonized with nature. Fabrics dyed or finished with natural herbs can render added positive effects on the health of the wearer. It is well known that skin absorbs some elements which come in its contacts. This may be used to provide softening of skin, soothing and healing effects by finishing or dyeing of textiles or garments which are in constant touch with the skin always. Aloe vera is considered as a miracle plant with all its virtues like healing properties, analgesic effect, antimicrobial properties, anti-radiation, detoxifying agent, moisturizing and anti-ageing mechanism. Both oral intake and topical dressings have been documented to facilitate healing of any kind of skin wound, burn, or scald. It is also found to have antimicrobial properties. Procedures for dyeing: Treated as direct dye Aloe solution + nitric acid + common salt for Fabrics Cotton. Treated as acid dye Aloe leaf solution + concentrated nitric acid Cotton, silk, wool, Treated as mordant dye, Dyeing after cationization of cotton, Treated as mordant dye, Aloe solution + nitric acid + common salt + sodium hydroxide for cotton fabric , Treated as mordant dye, First treated with myrabolan + ferrous sulphate. Then dyed with aloe solution + nitric acid, Treated as mordant dye, First treated with myrabolan + alum. Then dyed with aloe solution + nitric acid + sodium hydroxide, treated as mordant dye, First treated with tannic acid + ferrous sulphate. Then dyed with aloe solution + nitric acid + sodium hydroxide, Treated as mordant dye, First treated with alum + ferrous sulphate, then dyed with the aloe solution + nitric acid + sodium hydroxide (Cationization of cotton was done by treating it with cationizing agent namely, Optifix EC LIQ (procured from Clariant), 5% owf, 1:50 MLR, at room temperature for 30 minutes. The cationized cotton was then dyed with the aloe solution + nitric acid in a bath and after 10 minutes, sodium hydroxide was added. Dyeing was done at boiling temperature and MLR 1:30. Natural dyes also fall under different dye classes as direct, acid, disperse, vat and mordant. Tannins such as harar (myrabolan), tannic acid etc are considered natural mordants. By first dyeing, let us say cotton with these compounds, one introduces additional hydroxyl and carboxylic groups in the fibre. These groups by themselves can only increase the dye uptake of basic dyes such as berberine. Mordants are useful only with dyes which have electron donating groups (o-hydroxy) which can form a complex with transition metal ions.
