Method for recycling waste aramid-mica composite paper

Patent metadata

Field	Value
Publication number	US-12351982-B2
Application number	US-202217858952-A
Country	US
Kind code	B2
Filing date	Jul 6, 2022
Priority date	Apr 12, 2022
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

The disclosure relates to resource recycling, and more particularly to a green and efficient method for recycling waste aramid-mica composite paper. The method includes: dissolution of aramid-mica composite paper scraps, separation of mica flakes; phase separation, filtration, recycling of organic solvent and collection of aramid fiber.

First claim

What is claimed is:

1. A method for recycling waste aramid-mica composite paper, comprising:
(S1) pre-processing the waste aramid-mica composite paper to obtain a dehydrated aramid-mica composite paper scrap;
(S2) dissolving the dehydrated aramid-mica composite paper in a mixture solution to obtain a mixture system A, wherein the mixture solution comprises a dispersing agent, an alkali, and an organic solvent;
(S3) filtering the mixture system A with a primary filter to obtain a mica flake and an aramid fiber solution;
(S4) adding a replacement solvent to the aramid fiber solution for solvent replacement and phase separation to obtain an aramid fiber suspension;
(S5) filtering the aramid fiber suspension with a secondary filter to obtain an aramid fiber gel and a mixture system B composed of the organic solvent and the dispersing agent; and
(S6) subjecting the mixture system B to distillation at a preset temperature to recycle the organic solvent; and drying the aramid fiber gel to collect aramid fiber.

2. The method of claim 1 , wherein in step (S1), the waste aramid-mica composite paper is aramid-mica paper or a paper-based material with poly(m-phenylene isophthalamide) as polymer matrix.

3. The method of claim 1 , wherein a size of the dehydrated aramid-mica composite paper scrap is 2-5 cm 2 .

4. The method of claim 1 , wherein in step (S2), the mixture solution is prepared through steps of:
dissolving the alkali in the dispersing agent to form a mixture followed by addition of the organic solvent and stirring to obtain the mixture solution;
wherein a ratio of the dispersing agent to the alkali to the organic solvent is 1 mL:(1-2) g:(300-600) mL.

5. The method of claim 4 , wherein the dispersing agent is water, ethanol, methanol, or a combination thereof; the alkali is solid potassium hydroxide, solid sodium hydroxide, or a combination thereof; and the organic solvent is dimethyl sulfoxide, dimethyl formamide, or a combination thereof.

6. The method of claim 1 , wherein the primary filter is a 100-200 mesh filter; and the secondary filter mesh is a 400-1000 mesh filter.

7. The method of claim 1 , wherein in step (S4), a volume ratio of the replacement solvent to the aramid fiber solution is (2-3):1.

8. The method of claim 1 , wherein the replacement solvent is water or ethanol.

9. The method of claim 8 , wherein in step (S6), when the replacement solvent is water, the preset temperature is 100-105° C.; and when the replacement solvent is ethanol, the preset temperature is 75-78° C.

10. The method of claim 1 , wherein in step (S6), the drying of the aramid fiber gel is performed at 60-100° C. for 4-24 hours.

Assignees

• Shaanxi Univ Of Science & Technology

Inventors

• Lu Zhaoqing
• Jia Fengfeng
• Hua Li
• E Songfeng
• Liu Yuanqing
• Dong Jiayue
• Li Nan
• Geng Bo

Classifications

• D21C3/20

  with organic solvents {or in solvent environment} · CPC title

• D21C11/10

  Concentrating spent liquor by evaporation (evaporators B01D) · CPC title

• D21C5/022

  Chemicals therefor · CPC title

• B09B3/80

  involving an extraction step · CPC title

• C08J2377/00

  Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers · CPC title