Oxalic acid has several important roles in the textile industry, mainly including bleaching, descaling and reducing functions. The following are the main applications of oxalic acid in the textile field.
1, bleaching effect: oxalic acid has strong bleaching performance, can effectively remove pigments and impurities on cellulose, so that the fiber becomes whiter. It is commonly used in the bleaching treatment of natural fibers such as cotton, hemp, silk, etc. to improve the whiteness and gloss of the fibers.
2, rust removal: oxalic acid has reducing properties, can be with rust (iron oxide) chemical reaction, the generation of water-soluble iron oxalate, so as to effectively remove rust stains on the textile, to restore the cleanliness of the fabric.
3、Reducing effect: oxalic acid has reducing property, can react with some oxidizing agent, so it is often used as reducing agent in textile printing and dyeing process. For example, in the printing of the color development of pigment dyes, oxalic acid can replace ant acid or urea, nitrite reduction to nitrogen, to avoid the problem of the white ground is not white.
4, help dyeing role: in the dyeing process, oxalic acid can adjust the pH value of the dye solution, so that the dye solution is in a suitable acidic environment, which helps the dye better adsorption on the fabric, improve the uniformity of dyeing and color vividness.
5、Remove calcium and magnesium ions on fabrics: Calcium and magnesium ions in water may react with dyes or components in fabrics, affecting the dyeing effect or making fabrics feel hard. Oxalic acid can form soluble complexes with these metal ions, remove them and play a role in softening water quality, improving fabric feel and dyeing quality.
6、Fabric post-treatment: In the post-treatment process of fabrics, oxalic acid can be used to remove the residual impurities on the surface of fabrics, such as paste and auxiliaries, so as to make the surface of fabrics more polished and improve the quality and feel of fabrics.
7, other applications: oxalic acid is also used in textile flame retardant treatment and fire-resistant shaping, as a finishing agent crosslinked to the fabric catalyst. In addition, it is used as a washing and lifting agent in wool special dyeing to help remove stubborn color spots.
Caution: Oxalic acid is corrosive and care should be taken to protect the fibers when using it. For example, cotton fabrics need to be thoroughly washed after treatment with oxalic acid, otherwise the residual oxalic acid will damage the fibers and cause holes when drying.