Method for recycling cotton fibers from waste clothes

[0019] Example 1

[0020] A method for recovering cotton fibers from waste clothes, the waste clothes comprising polyester-cotton blended or single-component pure cotton fibers and purified fiber waste clothes, the steps of which include:

[0021] 1. Pretreatment: Add lye to waste clothes, then heat in a 20-60°C water bath for 1-2 hours, wash with water to remove stains and dirt on the clothes, and dry; cut and cut the dried clothes. When cutting, first remove the zipper or metal appendages; the lye added is 2%-6% NaOH solution, the solid-liquid ratio of waste clothes and NaOH solution is 1:5-1:20, and the shearing of the clothes after drying Size is 5 ~ 15cm.

[0022] 2. Pre-impregnation: add the cut cloth head into the alcoholysis reaction kettle, add glycol and depolymerization catalyst, pre-impregnate for 0.2-1h, the added glycol is ethylene glycol, and the depolymerization catalyst is acetic acid Zinc; the solid-liquid ratio of the added glycol to the cloth head is 1:2 to

[0025] Example 2

[0026] The waste medical white coats picked up from the garbage are soaked in a 2% NaOH solution at 60°C for 2 hours, and the solid-liquid ratio is 1:5. After cleaning the stains and dirt on the clothes, rinse them with clean water. Drain and dry the washed white coat.

[0027] Cut the cleaned white coat into 10 cm cloth ends according to the size of the reaction kettle.

[0028] Weigh 20 g of the cut cloth head and add it to the alcoholysis reaction kettle equipped with a stirring device and a condensation reflux device, add ethylene glycol according to the solid-liquid ratio of 1:2, then add 0.02 g of zinc acetate, and pre-dip 0.2~ 1 h, and then react at 170-200 °C for 2 h.

[0029] When the temperature dropped to 80°C, heat suction filtration to separate the depolymerized liquid slurry from the cotton fibers. The obtained cotton fibers were washed with water and dried to obtain 2.3 g of cotton fibers. The test confirmed that the cotton fibers did not occ

[0031] Example 3

[0032] The waste jeans, colorful autumn clothes and long pants picked up from the garbage were soaked in a 3% NaOH solution in a 60°C water bath for 2 hours, and the solid-to-liquid ratio was 1:10. After cleaning the stains and dirt on the clothes, rinse them with clean water. Drain and dry the washed clothes.

[0033] Cut the cleaned clothes into 10 cm cloth ends according to the size of the reactor.

[0034] Weigh 250 g of the cut cloth head and add it to the alcoholysis reaction kettle equipped with a stirring device and a condensation reflux device. Add ethylene glycol according to the solid-liquid ratio of 1:5, then add 0.2 g of zinc acetate, and pre-soak for 1 h. . The reaction was carried out at a temperature of 170-200 °C for 2 h.

[0035] When the temperature drops to 80°C, heat suction filtration, separate the depolymerized liquid slurry from the cotton fibers, and clean the cotton fibers. Add 2% hydrogen peroxide to the cleaned cotton fibers f