阅读说明：本技术 一种聚酰亚胺及其混纺纺织品的分离回收方法 (Separation and recovery method of polyimide and blended textile thereof ) 是由 李瑞卿 李继往 魏炳举 于 2020-05-26 设计创作，主要内容包括：本申请公开了一种聚酰亚胺及其混纺纺织品的分离回收方法,包括以下步骤：将聚酰亚胺及其混纺纺织品浸泡于酸性溶液中进行处理,处理时间为30~60min,处理温度为90~200℃,使耐酸性弱的纤维溶解,得到未能溶解的第一预处理材料；对第一预处理材料进行水洗,将水洗后的第一预处理材料浸泡于碱性溶液中进行酸碱中和处理,处理时间为30~40min,处理温度为60~90℃,得到未能溶解的第二预处理材料；对第二预处理材料进行水洗,水洗干净后得到纯度较高的聚酰亚胺纤维。本申请能够对聚酰亚胺及其混纺纺织品进行分离、回收,得到纯度较高的聚酰亚胺纤维,且方法价廉、简单、环保、高效。(The application discloses a separation and recovery method of polyimide and blended textiles thereof, which comprises the following steps: soaking polyimide and blended textiles thereof in an acid solution for treatment for 30-60 min at 90-200 ℃ to dissolve fibers with weak acid resistance to obtain an undissolved first pretreatment material; washing the first pretreatment material with water, soaking the washed first pretreatment material in an alkaline solution for acid-base neutralization treatment, wherein the treatment time is 30-40 min, and the treatment temperature is 60-90 ℃, so as to obtain an insoluble second pretreatment material; and washing the second pretreatment material with water, and obtaining the polyimide fiber with higher purity after the second pretreatment material is washed with water. The method can separate and recover the polyimide and the blended textile thereof to obtain the polyimide fiber with higher purity, and is cheap, simple, environment-friendly and efficient.)

1. A separation and recovery method of polyimide and blended textiles thereof is characterized by comprising the following steps:

soaking polyimide and blended textiles thereof in an acid solution for treatment for 30-60 min at 90-200 ℃ to dissolve fibers with weak acid resistance to obtain an undissolved first pretreatment material;

washing the first pretreatment material with water, soaking the washed first pretreatment material in an alkaline solution for acid-base neutralization treatment, wherein the treatment time is 30-40 min, and the treatment temperature is 60-90 ℃, so that an insoluble second pretreatment material is obtained;

and washing the second pretreatment material with water, and obtaining the polyimide fiber with higher purity after the second pretreatment material is washed with water.

2. The method for separating and recovering the polyimide and the blended textile thereof according to claim 1, wherein the acidic solution is an aqueous acid solution, and the mass fraction of the acid is 20-50%.

3. The method for separating and recovering the polyimide and the blended textile thereof according to claim 2, wherein the acidic solution comprises one or more of hydrochloric acid, sulfuric acid and nitric acid.

4. The method for separating and recovering the polyimide and the blended textile thereof according to claim 1, wherein the alkaline solution is an aqueous solution of alkali, and the mass fraction of the alkali is 5-20%.

5. The method for separating and recovering the polyimide and the blended textile thereof according to claim 4, wherein the aqueous solution of the alkali comprises one or both of an aqueous solution of sodium hydroxide and aqueous ammonia.

6. The method for separating and recovering the polyimide and the blended textile thereof according to claim 1, wherein the polyimide and the blended textile thereof are from various recovered waste materials, and the polyimide and the blended textile thereof are made of one or more of knitted fabrics, woven fabrics, non-woven fabrics and geotextiles.

7. The method for separating and recovering the polyimide and the blended textile thereof according to claim 1, wherein the polyimide and the blended textile thereof comprise a polyimide textile or a textile blended by the polyimide and the strong acid-intolerant fiber, and the strong acid-intolerant fiber is one or more of cotton, hemp, viscose and nylon.

8. The method for separating and recovering polyimide and blended textiles thereof as claimed in claim 1, wherein both the acidic solution and the alkaline solution are circulated.

9. The method for separating and recovering the polyimide and the blended textile thereof according to claim 1, wherein the reaction pressure of the polyimide and the blended textile thereof in the treatment process is normal pressure or high pressure.

10. A method for decomposing and recycling polyimide and blended textiles thereof is characterized in that the polyimide and the blended textiles thereof are pretreated by the method for separating and recycling the polyimide and the blended textiles thereof according to any one of claims 1 to 9.

Technical Field

The application relates to the technical field of environmental protection recovery, in particular to a separation and recovery method of polyimide and blended textiles thereof.

Background

Polyimide fibers are a polymeric material containing imide rings in the main molecular chain. Because of having a highly conjugated main chain structure, the fiber has high-strength and high-modulus mechanical properties, excellent performance, thermal oxidation resistance stability, for example, the limit oxygen index is higher than that of Kevlar 49 sold in the market, excellent flame retardance, no molten drop when being baked by open fire, and self-extinguishing when being away from fire; excellent heat insulation performance, and the heat conductivity coefficient is only one dozen times of that of terylene and nylon; excellent low temperature resistance, and can not be brittle in liquid ammonia with the temperature lower than-260 ℃; the capability of resisting ultraviolet rays and radiation is strong; good spinnability and strong spinnability.

Polyimide fibers are versatile: high temperature resistant flame retardant protective clothing, parachutes, honeycomb structures and heat sealing materials, composite reinforcing agents and anti-radiation materials; manufacturing fireproof flame-retardant clothes such as protective clothes of armored troops, racing car flame-retardant clothes, flight clothes and the like; comfortable and warm functional clothes such as military clothes, casual clothes for eliminating bad body odor, special clothes for preventing biochemical weapons, medical sanitary protective clothes, high-efficiency smoke protective masks and the like are manufactured.

Polyimide fibers have such many advantages, and are highly spinnable, so that they are used in the field of civil use from a special field. As civil textiles, the polyimide can be knitted or woven, pure polyimide can be used for manufacturing textiles, and the polyimide can also be blended with other fibers; polyimide is used as civil textiles, and various colors and various functional finishes need to be dyed, so that the consumption of the polyimide textiles is very large, and how to recycle the waste polyimide textiles becomes a problem to be solved urgently. CN1026414C discloses a method for recovering polyimide film waste, CN1324789 discloses a method for recovering polyimide by using an alkali aqueous solution and sulfuric acid, CN109503614 discloses a method for recovering polyimide by using hydrazine hydrate, and CN104945268A discloses a method for recovering and processing modified polyimide film waste.

However, the existing waste polyimide textiles are usually not pure polyimide fibers, but are often blended with other fibers, or dyes and other functional auxiliaries exist on the polyimide fibers, and when the polyimide textiles are recycled in the prior art, the purity is not high, so that the subsequent industrial recycling application is influenced.

Disclosure of Invention

The technical problem mainly solved by the application is to provide a method for separating and recovering polyimide and blended textiles thereof, which can separate and recover polyimide waste textiles containing cotton, hemp, viscose, nylon and other strong acid-intolerant blended materials or polyimide waste textiles containing dyes and auxiliaries, and is low in price, simple, environment-friendly and efficient.

In order to solve the technical problem, the application adopts a technical scheme that: the separation and recovery method of the polyimide and the blended textile thereof comprises the following steps:

the waste polyimide textile is soaked in an acid solution for treatment, and the characteristics that polyimide fibers resist strong acid, and the remaining materials such as blended cotton, hemp, viscose, nylon, dye, auxiliaries and the like do not resist strong acid and are easy to decompose are utilized for preliminary separation. The treatment time is 30-60 min, the treatment temperature is 90-200 ℃, and the fibers with weak acid resistance are dissolved to obtain an undissolved first pretreatment material;

washing the first pretreatment material with water, soaking the washed first pretreatment material in an alkaline solution for acid-base neutralization treatment, wherein the treatment time is 30-40 min, and the treatment temperature is 60-90 ℃, so as to obtain an insoluble second pretreatment material;

and washing the second pretreatment material with water, and obtaining the polyimide fiber with higher purity after the second pretreatment material is washed with water.

Further, the acid solution is an acid aqueous solution, and the mass fraction of acid in the acid aqueous solution is 20-50%.

Further, the aqueous acid solution includes one or more of hydrochloric acid, sulfuric acid, and nitric acid.

Furthermore, hydrogen peroxide can be added into the acidic solution.

Further, the alkaline solution is an alkaline aqueous solution, and the mass fraction of the alkali in the alkaline aqueous solution is 5-20%.

Further, the aqueous alkali solution includes one or both of an aqueous sodium hydroxide solution and aqueous ammonia.

Furthermore, the polyimide and the blended textile thereof are one or more of waste clothing leftover materials, clothing, towels and shoes and hats, and the material of the waste polyimide textile is one or more of knitted fabrics, woven fabrics, non-woven fabrics and geotextiles.

Furthermore, the polyimide waste textile comprises polyimide textile or textile blended by polyimide and various strong acid-intolerant fibers such as cotton, hemp, viscose, nylon and the like.

Further, both the acidic solution and the basic solution are circulated.

Further, the method for separating and recovering the polyimide waste textiles is characterized in that the reaction pressure of the polyimide waste textiles in the treatment process is normal pressure or high pressure.

The application also provides a method for decomposing and recycling the polyimide and the blended textile thereof, and the polyimide and the blended textile thereof are pretreated by any one of the methods for separating and recycling the polyimide and the blended textile thereof.

The beneficial effect of this application is: different from the situation of the prior art, the application provides a separation and recovery method of polyimide and blended textiles thereof, which comprises the following steps: soaking polyimide and blended textiles thereof in an acid solution for treatment, so that fibers with weak acid resistance are dissolved, and an undissolved first pretreatment material is obtained; washing the first pretreatment material with water, soaking the washed first pretreatment material in an alkaline solution for acid-base neutralization treatment to obtain an insoluble second pretreatment material; and washing the second pretreatment material with water, and obtaining the high-purity polyimide fiber after the second pretreatment material is washed clean with water. The method can be used for treating the polyimide and the blended textile thereof or the waste polyimide textile with the dye and the auxiliary agent, can separate and recover the high-purity polyimide fiber, and is low in price, simple, environment-friendly and efficient.

Drawings

FIG. 1: the application discloses a flow schematic diagram of an embodiment of a separation and recovery method of polyimide and blended textiles thereof.

Detailed Description

In order to make the purpose, technical solution and effect of the present application clearer and clearer, the present application is further described in detail below with reference to the accompanying drawings and examples.

Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a separation and recovery method of polyimide and blended textiles thereof, and the method comprises the following steps:

step S101: and soaking the polyimide and the blended textile thereof in an acid solution for treatment for 30-60 min at the treatment temperature of 90-200 ℃ to dissolve the fibers with weak acid resistance, thereby obtaining an insoluble first pretreatment material.

Polyimide fibers have excellent acid resistance and are relatively difficult to be subjected to acid hydrolysis. The method comprises the steps of soaking polyimide waste textiles in an acid solution, setting the temperature range to be lower than 90-200 ℃ of thermal decomposition of polyimide, and setting the time to be 30-60 min, wherein in the time period, other relatively acid-fast fibers or dyes and auxiliaries except polyimide fibers in the polyimide and the blended textiles thereof are subjected to acidolysis, if the time is too short, materials except the polyimide fibers are not easy to treat cleanly, and if the time is too long, the polyimide fibers can also be subjected to relatively severe acidolysis to influence the yield of the polyimide fibers.

Step S102: and (3) washing the first pretreatment material, soaking the washed first pretreatment material in an alkaline solution for acid-base neutralization treatment, wherein the treatment time is 30-40 min, and the treatment temperature is 60-90 ℃, so that an insoluble second pretreatment material is obtained.

The first pretreatment material once immersed in the acidic solution is washed with water to wash away the acidic solution from the polyimide fibers. Since the acid on the polyimide fiber cannot be completely removed by only water washing, the first pretreatment material after water washing is immersed in an alkaline solution to remove the remaining acid by neutralization reaction treatment. Aiming at the relatively poor alkali resistance of polyimide, the treatment time of neutralization treatment is 30-40 min, the treatment temperature is 60-90 ℃, and the influence on polyimide fibers can be reduced as much as possible while thorough neutralization is ensured; the slightly less basic nature also allows further removal of other impurities, a small amount of polyimide can be lost, but the recovered polyimide is more pure.

Step S103: and washing the second pretreatment material with water, and obtaining the polyimide fiber with higher purity after the second pretreatment material is washed with water.

This application is handled through polyimide waste textile to the blending or the polyimide waste textile who has dyestuff and auxiliary agent, can separate and retrieve pure polyimide fiber, can retrieve for the degradation of follow-up polyimide fiber and provide pure raw and other materials, and the method is cheap, simple, environmental protection, high-efficient.

The acidic solution is a solution with a pH value of less than 7, and can be a solution of acid, or a solution of other compounds with acidic solution, such as ammonium nitrate. In one embodiment, the acid solution is an aqueous solution of an acid, wherein the mass fraction of the acid is 20% to 50%, for example, 30%, 35%, 40%, 45%, and the like, and specifically, the acid solution may be one or more of hydrochloric acid, sulfuric acid, and nitric acid. The polyimide waste textile is treated by the acid solution, and other fibers or dyes and auxiliaries which are not relatively acid-resistant except the polyimide fibers in the polyimide waste textile can be removed.

The alkaline solution refers to a solution with a pH value of more than 7, and can be a solution of alkali or a solution of other compounds with alkaline solution, such as sodium carbonate and trisodium phosphate. In one embodiment, the alkaline solution is an aqueous solution of alkali, wherein the mass fraction of the alkali is 5% to 20%, for example, 10%, 13%, 15%, 18%, etc., specifically, the aqueous solution of alkali may be one or both of an aqueous solution of sodium hydroxide and aqueous ammonia, and the alkaline solution may neutralize the acid remaining on the waste polyimide textiles.

In one embodiment, the polyimide and its blended textile include polyimide textiles or textiles blended with polyimide and various fibers. The polyimide textile is not pure polyimide fiber, and is usually attached with various dyes and auxiliary agents, or is directly blended with other fibers, such as textiles blended by polyimide and various strong acid-intolerant fibers such as cotton, hemp, viscose, nylon and the like. The waste polyimide textile can be a polyimide textile containing various auxiliaries or dyes, and can also be a textile blended by polyimide and various fibers, the textile can be made of waste clothing leftover materials, clothing, towels, shoes and hats and the like, and the material can be one or more of knitted fabrics, woven fabrics, non-woven fabrics and geotextiles.

In one embodiment, the polyimide and the blended textile thereof are soaked in an acidic solution to remove impurities other than polyimide fibers, wherein the acidic solution is in a circulating flow. Through the circulation flow of the acid solution, the polyimide waste textile can be fully contacted with the acid solution, and the separation and purification rate of the polyimide fiber is higher. The acid-treated polyimide fiber is washed by water and then soaked in an alkaline solution for neutralization reaction, wherein the alkaline solution also flows circularly, so that the neutralization reaction rate of the alkaline solution is improved. In the whole separation and recovery process of the polyimide waste textile, the reaction pressure can be normal pressure or high pressure, wherein the high pressure is higher than the normal pressure. When the reaction pressure is higher than normal pressure, the rate of each reaction can be further accelerated.

The separation and recovery method provided by the application can separate and recover pure polyimide fibers by treating the blended polyimide waste textiles or the polyimide waste textiles with the dye and the auxiliary agent, can provide pure raw materials for the degradation and recovery of the subsequent polyimide fibers, and is low in cost, simple, environment-friendly and efficient. Based on the above, the application also provides a polyimide waste textile decomposition and recovery method, which comprises the steps of carrying out pretreatment by any one of the above polyimide waste textile separation and recovery methods to obtain pure polyimide fibers, and then further decomposing the pure polyimide fibers to recover raw materials with higher purity.

The present application will be illustrated and explained below by means of several groups of specific experimental examples, which should not be construed as limiting the scope of the present application.