CN103642065A - Process of regenerating nylon 6 and nylon 66 from waste carpet by selective dissolving-precipitating method - Google Patents

Abstract

The invention relates to a process for regenerating nylon 6 and nylon 66 from waste nylon by a selective dissolution-precipitation method. It is characterized in the process of using different organic solvents to selectively dissolve nylon 6 and nylon 66, and using water as a precipitating agent to regenerate nylon 6 and nylon 66 from organic solvents. The invention has the characteristics of simple operation and high recycling rate, can effectively recycle nylon 6 and nylon 66 in waste carpets, avoid waste of resources, and also explores a new process for industrial recycling of waste carpets.

Description

A selective dissolution-precipitation method for regenerating nylon 6 and nylon 66 from waste carpets

technical field

The invention relates to a process for selectively dissolving waste carpets with an organic solvent and using deionized water as a precipitating agent to obtain nylon 6 and nylon 66. The invention belongs to the technical field of high molecular polymer recycling application.

Background technique

Polymer materials have good functionality and practicability, which promotes the rapid development of polymer materials. While polymer materials bring convenience to people's lives, they also cause serious pollution problems of waste polymers. The recycling of waste polymers, maintaining the sustainable development of society, and realizing the recycling of waste polymers have aroused widespread concern.

Nylon carpet is the earliest chemical fiber carpet used in large quantities. It has excellent characteristics such as wear resistance, high strength and acid and alkali resistance. The waste nylon carpet is mainly composed of suede made of nylon 6 (polycaprolactam) and nylon 66 (polyhexamethylene adipate) fibers, polypropylene lining, and styrene-butadiene latex adhesive filled with a large amount of calcium carbonate. At present, the treatment methods of waste carpet mainly include landfill recycling, energy recovery, material recovery and chemical recovery. With the continuous development of the concept of environmental protection, green economy, circular economy and sustainable development advocated by the society, the recycling of nylon 6 and nylon 66 from waste carpets has attracted more and more attention.

Contents of the invention

The main purpose of the present invention is to provide a chemical recycling process to regenerate nylon 6 and nylon 66 from waste carpets, which can realize recycling of effective components (nylon 6 and nylon 66) in waste carpets. The process has the advantages of high recycling rate, high quality of recycled products, simple process operation, etc., can effectively realize the recycling of resources, reduce the production cost of nylon carpet, and has the prospect of industrialization promotion.

The present invention specifically adopts the following technical solutions:

A kind of selective dissolution-precipitation method regenerates the technique of nylon 6 and nylon 66 from waste and old carpet, its feature mainly comprises the following steps:

(1). Crush and sieve waste carpets to obtain crude fibers.

(2). Mix the treated crude fiber and solvent dimethyl sulfoxide at a mass ratio of 1:8-10, heat and stir at 110°C-130°C, and keep the temperature constant for 60 minutes.

(3). Then filter while it is hot, and rinse the undissolved residue with hot dimethyl sulfoxide, then add deionized water to the obtained filtrate, you can see that there is precipitation, the precipitate is nylon 6, and then filter The precipitate was washed three times with deionized water and dried.

(4). Mix the remaining residue in step 3 and formic acid in a mass ratio of 1:10-15, and stir at room temperature for 60 minutes.

(5). Filtrate, then add deionized water to the obtained filtrate, it can be seen that there is a precipitate, which is nylon 66, then filter the precipitate, wash with deionized water three times, and dry.

(6). The reagents used in the reaction are collected, separated by distillation, and recycled repeatedly.

The advantages of the present invention: it can regenerate waste carpets into valuable resources, which not only effectively alleviates the pollution of waste polymers, but also contributes to the sustainable development of society; the process is simple, the recycling rate is high, and the quality of recycled products is high. High; fully realize the recycling of waste resources, low energy consumption, in line with environmental protection requirements; dimethyl sulfoxide, formic acid and deionized water used in the recycling process can be separated by distillation and recycled, reducing The production cost is reduced, and it has the prospect of industrial application.

Detailed ways

Example 1

The waste carpets are crushed and sieved to obtain crude fibers. In a 50ml three-necked flask equipped with a condensing reflux device on the top, mix the treated crude fiber with dimethyl sulfoxide at a mass ratio of 1:8, heat and stir, and control the temperature at 110°C to 130°C, and keep the temperature constant for 60 minutes, then Filter, and wash the residue with hot dimethyl sulfoxide, add an appropriate amount of deionized water to the obtained filtrate, a precipitate is precipitated, and the precipitate is nylon 6, filter the precipitate, wash with deionized water three times, and then vacuum at 60 ° C Let dry for 12 hours. At the same time, the residue and formic acid were mixed and stirred at room temperature for 60 minutes at a mass ratio of 1:10, then filtered, and an appropriate amount of deionized water was added to the filtrate, and a precipitate was precipitated, which was nylon 66. The precipitate was filtered and washed with deionized water three times, and then dried under vacuum at 60 °C for 12 hours. The reagents used in the reaction are collected, separated by distillation, and recycled repeatedly. The yield of nylon 6 was 13.62%, and that of nylon 66 was 56.58%.

Example 2

The waste carpets are crushed and sieved to obtain crude fibers. In a 50ml three-neck flask equipped with a condensing reflux device on the top, mix the treated crude fiber with dimethyl sulfoxide at a mass ratio of 1:10, heat and stir, and control the temperature at 110°C to 130°C for 60 minutes at a constant temperature, then Filter, and wash the residue with hot dimethyl sulfoxide, add an appropriate amount of deionized water to the obtained filtrate, a precipitate is precipitated, and the precipitate is nylon 6, filter the precipitate, wash with deionized water three times, and then vacuum at 60 ° C Let dry for 12 hours. At the same time, the residue and formic acid were mixed and stirred at room temperature for 60 minutes at a mass ratio of 1:10, then filtered, and an appropriate amount of deionized water was added to the filtrate, and a precipitate was precipitated, which was nylon 66. The precipitate was filtered and washed with deionized water three times, and then dried under vacuum at 60 °C for 12 hours. The reagents used in the reaction are collected, separated by distillation, and recycled repeatedly. The yield of nylon 6 was 14.06%, and that of nylon 66 was 57.17%.

Example 3

The waste carpets are crushed and sieved to obtain crude fibers. In a 50ml three-necked flask equipped with a condensing reflux device on the top, mix the treated crude fiber with dimethyl sulfoxide at a mass ratio of 1:8, heat and stir, and control the temperature at 110°C to 130°C, and keep the temperature constant for 60 minutes, then Filter, and wash the residue with hot dimethyl sulfoxide, add an appropriate amount of deionized water to the obtained filtrate, a precipitate is precipitated, and the precipitate is nylon 6, filter the precipitate, wash with deionized water three times, and then vacuum at 60 ° C Let dry for 12 hours. At the same time, the residue and formic acid were mixed and stirred at room temperature for 60 minutes at a mass ratio of 1:15, then filtered, and an appropriate amount of deionized water was added to the filtrate, and a precipitate was precipitated, which was nylon 66. The precipitate was filtered and washed with deionized water three times, and then dried under vacuum at 60 °C for 12 hours. The reagents used in the reaction are collected, separated by distillation, and recycled repeatedly. The yield of nylon 6 was 13.95%, and that of nylon 66 was 58.06%.

Example 4

The waste carpets are crushed and sieved to obtain crude fibers. In a 50ml three-neck flask equipped with a condensing reflux device on the top, mix the treated crude fiber with dimethyl sulfoxide at a mass ratio of 1:10, heat and stir, and control the temperature at 110°C to 130°C for 60 minutes at a constant temperature, then Filter, and wash the residue with hot dimethyl sulfoxide, add an appropriate amount of deionized water to the obtained filtrate, a precipitate is precipitated, and the precipitate is nylon 6, filter the precipitate, wash with deionized water three times, and then vacuum at 60 ° C Let dry for 12 hours. At the same time, the residue and formic acid were mixed and stirred at room temperature for 60 minutes at a mass ratio of 1:15, then filtered, and an appropriate amount of deionized water was added to the filtrate, and a precipitate was precipitated, which was nylon 66. The precipitate was filtered and washed with deionized water three times, and then dried under vacuum at 60 °C for 12 hours. The reagents used in the reaction are collected, separated by distillation, and recycled repeatedly. The yield of nylon 6 was 14.46%, and that of nylon 66 was 58.62%.

Claims (7)

1. a selective dissolution-precipitation method is characterized in that it comprises the steps of regenerating nylon 6 and nylon 66 from waste and old carpets: the waste and old carpets are crushed and sieved to obtain crude fibers; the crude fibers and dimethyl Mix and stir the sulfoxide according to a certain mass ratio, and heat at a constant temperature for a period of time; filter the reacted mixed solution while it is hot, add deionized water to the filtrate, wash and dry the precipitated precipitate; mix the remaining residue and formic acid according to a certain The mass ratio is mixed and stirred for a period of time; the mixed solution after the reaction is filtered, deionized water is added to the filtrate, and the precipitated precipitate is washed and dried; the reagents used in the reaction are distilled and recycled repeatedly. 2. A process for regenerating nylon 6 and nylon 66 from waste carpets by a selective dissolution-precipitation method according to claim 1, characterized in that: crude fiber and dimethyl sulfoxide are in a mass ratio of 1:8-10 Mix, control the heating temperature at 110°C to 130°C, and stir at constant temperature for 60 minutes. 3. A kind of selective dissolution-precipitation method according to claim 1 is the process of regenerating nylon 6 and nylon 66 from waste and old carpets, it is characterized in that: the mixed solution after the reaction of crude fiber and dimethyl sulfoxide should be hot Filter and wash the residue with hot dimethyl sulfoxide, then add an appropriate amount of deionized water to the filtrate to precipitate a precipitate, which is nylon 6, then filter the precipitate, wash and dry. 4. A selective dissolution-precipitation method for regenerating nylon 6 and nylon 66 from waste carpets according to claim 1, characterized in that: the remaining residue is mixed with formic acid in a mass ratio of 1:10-15 , react at room temperature, and the reaction time is 60 minutes. 5. A kind of selective dissolution-precipitation method according to claim 1 is the process of regenerating nylon 6 and nylon 66 from waste and old carpets, characterized in that: the product after the reaction of residue and formic acid is filtered, and then added to the filtrate An appropriate amount of deionized water is used to precipitate a precipitate, which is nylon 66, and then the precipitate is filtered, washed, and dried. 6. A selective dissolution-precipitation method according to claim 1 is a process for regenerating nylon 6 and nylon 66 from waste carpets, characterized in that: nylon 6 and nylon 66 are dried under vacuum at 60°C for 12 hours . 7. A selective dissolution-precipitation method according to claim 1 is a process for regenerating nylon 6 and nylon 66 from waste carpets, characterized in that: the reagents used in the reaction are distilled and reused repeatedly to save production costs .