The sequestering agent in textile process is widely used in different stages.
The application of sequestering agent in printing process:
The dye concentration is high in the printing paste, so the solubility of the dye directly affects the quality of printing and the quality of water will has greater effect. Adding sequestering agent to the printing paste can reduce the impact of water quality. The insoluble calcium salt in the hard water used as the thickening agent in reactive dye printing can generate insoluble calcium phosphate, which is difficult to be washed in finishing process. In the presence of sequestering agent, the dye solubility is increased, the color quantity is increased, the color of printing product is bright, and it is helpful to remove the residue after printing.
The calcium carbonate and other metal ions in hard water deposits that sink on the fabric influcing its hydroscpicity, further affect the next process, which finally affect the hand feeling and whiteness of fabric. The scale on the equipment affects the function of the equipment: the scale in the heat exchanger affects the heat transfer efficiency, the pipe is blocked and the valve fails, thus affecting the normal operation of the equipment. The scale on the roller cause graze between the fabric. The scale is mostly crystal. For example, CaCO3 with ionic lattice, is strict arrangement hard scale combined by positively charged Ca2 + and the negatively charged CO32 in a certain direction.
The chelation of sequestering agent in textile process to Ca2 + suppresses the lattice growth to a certain direction. So crystal structure of CaCO3 no longer grows in normal rule, generating larger non-crystalline granule. Part of the granule adsorb on the crystal, as the growth of the crystal it comes into the crystal lattice, resulting the dislocation in the CaCO3 crystals. Even though some of the crystals are still growing, it is difficult to form a tight layer of scale, which turns the CaCO3 hard scale into a soft scale that can easily be washed away.
Only several milligram Polycarboxylic acid sequestering agent can be used to prevent hundred milligram calcium carbonate precipitates in one liter solvent , so the scale removing performance of sequestering agent in textile process is excellent.