Recycled Polyester Resin Dye Extraction from Colored PET Fabric

The patent applies preliminary action by performing dye extraction from colored PET fibers before depolymerization. This pre-treatment removes coloring components in advance, preventing them from interfering with subsequent purification steps and final resin quality. The extraction is conducted using organic solvents or oxidizing agents prior to breaking down the polymer, thereby simplifying the overall purification process while maintaining excellent color tone in the recycled resin.

The patent directly extracts and removes dye components from colored PET fibers using extraction methods with organic solvents or oxidizing agents. By taking out the harmful coloring components before depolymerization, the process achieves high-quality color tone in the final resin without requiring complex multi-stage purification systems, thus resolving the contradiction between quality and complexity.

The patent performs dye extraction as a preliminary action before depolymerization, removing coloring components that would otherwise require energy-intensive removal during monomer purification. This pre-removal of impurities reduces the burden on subsequent purification steps, allowing simpler and less energy-consuming methods to achieve the required monomer purity.

The patent employs disposable activated carbon during the purification process to adsorb remaining impurities from the BHET monomer solution. This simple, inexpensive material provides effective purification without requiring complex distillation equipment or high energy input, replacing energy-intensive molecular distillation with a more efficient and economical approach.

The patent performs dye extraction as a preliminary action before depolymerization, removing the majority of coloring components in advance. This pre-treatment enables the use of simple purification steps afterward (such as activated carbon treatment and filtration) while still achieving excellent color tone quality in the final resin, as the bulk of color contaminants have already been removed.

The patent uses organic solvents or oxidizing agents as intermediaries to extract dyes from colored PET fibers before depolymerization. These intermediary substances facilitate the removal of coloring components, enabling subsequent simple purification steps to produce high-quality resin with excellent color tone that would otherwise require complex purification processes.