2022-09-09 Views: 0
Dyeing and printing industry: Fixing agents are one of the important auxiliaries in the dyeing and printing industry. They are auxiliaries used to enhance the wet fastness of dyes on fabrics. It can form insoluble colored substances with dyes on fabrics, thereby enhancing the washing and perspiration fastness of the colors, and sometimes even improving their light fastness.
Tannin itself has a color and is a natural dye. Due to the different extracted plants, they present colors such as light yellow, light brown, and light brown. According to the chemical properties of tannins, the parent substances of condensed tannins, catechins, originate from proanthocyanidins and are colorless by themselves. Through oxidation and condensation, they change color and become natural dyes.
Furniture wood industry: Some woods contain tannin (tannin, also known as plant tannin), which is a mixture of polyphenols. When it comes into contact with iron under humid conditions, the tannin in it will undergo a chemical reaction (complexation reaction) with iron to form iron tannate.
Iron tannate is black and is the main raw material used to make ink, thus causing the color of wood to turn black. Depending on the amount of iron and the duration of contact between the wood and iron, the color of the wood changes from light gray to bluish black.
Therefore, wood furniture containing tannin will change color after a period of time, which is the color of classical furniture.
Industrial rust removal: Tannic acid is a rust converter. It can undergo a chemical reaction with iron oxide, the main component of the rust layer, to form a stable network structure coordination compound, thereby effectively converting the rust into a protective film layer and firmly bonding it to the iron substrate.
