CN1244729C - Waste polyurethane fober regenerating and reusing method - Google Patents

Abstract

The invention relates to a method for recycling polyurethane fiber waste. The method is to degrade dry-spun, wet-spun, melt-spun polyurethane fiber wastes into liquid oligomers under the action of an alcoholysis agent. After the oligomers are separated and purified, polyols with a certain hydroxyl value can be obtained. Alcohols can react with isocyanates and chain extenders to resynthesize polyurethanes. The polyurethane fiber waste recycling method of the invention has the advantages of simple operation, short process flow and high recovery rate, and realizes the recycling of the polyurethane fiber waste.

Description

A kind of polyurethane fiber waste recycling method

technical field

The invention relates to the field of material technology, in particular to a method for recycling polyurethane fiber waste.

Background technique

Because spandex has very good elasticity and physical and mechanical properties, it has been widely used in textile, biomedical and other fields. In recent years, the spandex industry has developed rapidly and its output has doubled. At the same time, a large amount of waste is generated in the production and use of spandex. Therefore, recycling spandex waste becomes an urgent problem to be solved. These wastes can be disposed of by landfill and incineration, but this not only wastes a lot of chemical raw materials, but also causes land waste and air pollution, which is not in line with the sustainable development strategy of the earth. If these wastes can be recycled and reused, it will produce significant social benefits and have very important economic value. The current chemical recovery methods include pyrolysis, hydrolysis, alkaline hydrolysis, etc., but they have not been paid attention to because of the complexity of the process and the difficulty in separating the products. There are also materials that introduce the alcoholysis method, but most of the degraded polyurethane wastes are polyurethane foams, elastomers, etc. The research on the recycling of polyurethane fiber waste by using alcoholysis agent has not been reported yet.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for recycling and reusing polyurethane fiber waste with simple operation, short process flow and high recovery rate, and to synthesize new polyurethane materials from degraded and regenerated materials, so as to realize the waste of polyurethane fiber material recycling.

The recovery and recycling of the polyurethane fiber waste disclosed by the present invention is realized through the following technical solutions:

Degrade dry-spun polyurethane fiber waste, wet-spun polyurethane fiber waste, and melt-spun polyurethane fiber waste into oligomer liquids in the temperature range of 120-240°C under the action of an alcoholysis agent or an alcoholysis agent and a catalyst , The polyol obtained after separation and purification is reacted with isocyanate and chain extender to obtain a new polyurethane product.

The alcoholysis agent described in the method of the present invention is selected from C ₂ -C ₆ glycols, including: ethylene glycol, ethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol and all mixture of alcohols. Preferred alcoholysis agents are ethylene glycol, 1,4-butanediol or dipropylene glycol.

Adding a catalyst in the alcohol degradation reaction process of the present invention can accelerate the degradation reaction speed and reduce the degradation reaction time. The catalyst is selected from organometallic catalysts, tertiary amine catalysts, organotin catalysts or mixtures thereof. Wherein the organometallic catalyst is selected from one or more of potassium acetate, zinc acetate and sodium acetate; the tertiary amine catalyst is selected from one or more of triethylenediamine, triethylamine and triethanolamine; organotin The compound is selected from dibutyltin dilaurate, stannous octoate or mixtures thereof.

It is preferred, although not essential, to carry out the process of the invention in an atmosphere of inert gas nitrogen, argon, helium. During the reaction, the reaction mixture is preferably well stirred, and the progress of the reaction can be measured by any convenient method. In order to track the reaction process of polyurethane fiber waste, the dynamic viscosity, intrinsic viscosity or hydroxyl value of the degradation products are all effective test methods, and the reaction is generally completed within about 0.5 to 8 hours.

The degradation reaction is carried out in the presence of an alcoholysis agent, and the above-mentioned various catalysts are added as required. The reaction temperature can be any desired temperature, but generally 120-240°C is preferred, and the optimum temperature is 180-220°C.

In the present invention, the separation and purification method of the oligomer liquid obtained after the degradation of polyurethane fiber waste adopts a solvent extraction separation method, and the solvent is usually benzene or toluene. Polyols with a certain hydroxyl value after separation and purification can react with isocyanates and chain extenders to re-synthesize polyurethane. The selected isocyanate can be toluene diisocyanate, 4,4' diphenylmethane diisocyanate or other derivatives of isocyanate, and the selected chain extender can be a _C2 - _C6 diol, including ethylene glycol, 1,4 -Butanediol, etc. Polyurethane products obtained from recycling can be used as coatings, films, foams or fibers, etc.

Below in conjunction with example the present invention will be further described.

Detailed ways

Example 1

In a three-neck round bottom flask equipped with a stirrer, a condenser and a nitrogen inlet, 20 g of dry spinning polyurethane fiber waste and 40 g of ethylene glycol were added. Under nitrogen protection, the reaction mixture was heated to 200 °C and maintained at this temperature for 2 h. Then, after cooling to room temperature, the degradation product separated into two layers. The upper product was separated, washed with water and purified with benzene to obtain a refined polyol whose hydroxyl value was measured to be 92.3.

Example 2

The dry-spun polyurethane fiber waste in Example 1 was replaced with wet-spun polyurethane fiber waste for operation, and the obtained polyol had a hydroxyl value of 94.1.

Example 3

The dry-spun polyurethane fiber waste in Example 1 was replaced with melt-spun polyurethane fiber waste for operation, and the obtained polyol had a hydroxyl value of 106.3.

Example 4

In a three-necked round bottom flask equipped with a stirrer, a condenser and a nitrogen inlet, 20 g of dry spinning polyurethane fiber waste, 40 g of ethylene glycol, and 0.4 g of potassium acetate were added. Under nitrogen protection, the reaction mixture was heated to 190 °C and maintained at this temperature for 1 h. According to the method in Example 1, the degradation product was separated and purified to obtain a polyol, and its hydroxyl value was measured to be 105.8.

Example 5

The catalyst potassium acetate in Example 2 was replaced by dibutyltin dilaurate for operation, and the obtained polyol had a hydroxyl value of 111.5.

Example 6

The catalyst potassium acetate in Example 2 was replaced with triethylamine, and the degradation reaction temperature was set to 170°C for operation, and the obtained polyol had a hydroxyl value of 82.4.

Example 7

The alcoholysis agent ethylene glycol in Example 1 was replaced by 1,4-butanediol for operation, and the hydroxyl values of the polyols obtained after separation and purification were respectively 100.2.

Example 8

The reaction temperature in Example 1 was controlled at 240° C., and the degradation product was dark yellow in color and difficult to separate.

Example 9

The refined polyol obtained by the operation of Example 1 is reacted with 4,4' diphenylmethane diisocyanate and 1,4-butanediol in the desired molar ratio to obtain a polyurethane sheet with a breaking strength of 31.2Mpa and an elongation at break of is 450%.

Example 10

The refined polyol obtained in Example 5 was reacted with toluene diisocyanate and 1,4 butanediol in the required molar ratio to obtain a polyurethane sheet with a breaking strength of 35.3 MPa and an elongation at break of 420%.

Example 11

In Example 9, the chain extender 1,4-butanediol was replaced by ethylene glycol to obtain a polyurethane sheet with a breaking strength of 20.4 MPa and a breaking elongation of 400%.

Claims (6)

1, a kind of waste polyurethane fiber regenerating and reusing method, it is characterized in that this method be with dry-spinning polyurethane fiber discarded object, wet spinning polyurethane fiber discarded object, melt-spun polyurethane fiber wastes under the effect of alcoholysis agent or alcoholysis agent and catalyst, in 120～240 ℃ temperature range, be degraded into oligomer liquid, and through separating the polyalcohol that obtains after the purification, this polyalcohol synthesizes the new polyurethane products of acquisition with isocyanates and chain extender reaction again;

Wherein said alcoholysis agent is selected from C ₂-C ₆Dihydroxylic alcohols; Catalyst is selected from organo-metallic catalyst, tertiary amine catalyst, organotin catalysts or their mixture.

2, method according to claim 1 is characterized in that wherein said alcoholysis agent is selected from ethylene glycol, a condensed ethandiol, propylene glycol, dipropylene glycol, 1, the mixture of 4-butanediol and described alcohol.

3, method according to claim 1 is characterized in that wherein said organo-metallic catalyst is selected from one or more in potassium acetate, zinc acetate and the sodium acetate.

4, method according to claim 1 is characterized in that wherein said tertiary amine catalyst is selected from one or more in triethylenediamine, triethylamine and the triethanolamine.

5, method according to claim 1 is characterized in that wherein said organo-tin compound is selected from dibutyl tin two laurate fat, stannous octoate or their mixture.

6, method according to claim 1 is characterized in that wherein said separation and purification is meant that employing benzene or toluene extract separation.