CN115784886A

CN115784886A - Method for recycling plasticizer in PVC leather

Info

Publication number: CN115784886A
Application number: CN202211474883.0A
Authority: CN
Inventors: 孙海青; 陈金河; 林东坡; 熊本进; 徐波
Original assignee: Baierluohe New Material Technology Co ltd
Current assignee: Baierluohe New Material Technology Co ltd
Priority date: 2022-11-23
Filing date: 2022-11-23
Publication date: 2023-03-14

Abstract

The invention discloses a method for recovering a plasticizer in PVC leather, which comprises the following steps: s1: cutting PVC leather into fragments, placing the fragments in a container, and adding a certain amount of solvent until the liquid level of the solvent is over the PVC leather fragments; s2: heating the solid-liquid mixture in the container to a certain temperature, stirring and leaching for a period of time, and condensing and refluxing the evaporated solvent in a condensing reflux device to the container; s3: and filtering the solid-liquid mixture in the container, and distilling the filtrate under reduced pressure to remove the solvent to obtain the plasticizer. The method disclosed by the invention is simple to operate, strong in practicability, easy to realize industrialization of plasticizer recovery, capable of efficiently recovering the plasticizer in the PVC leather and realizing recycling of plasticizer resources, and good in economic benefit; the method is particularly suitable for PVC leather taking a calcium zinc stabilizer as a stabilizing system, and can avoid heavy metal elements in the recovered plasticizer.

Description

Method for recycling plasticizer in PVC leather

Technical Field

The invention relates to the technical field of plasticizer recovery, in particular to a method for recovering a plasticizer in PVC leather.

Background

The plasticizer is a commonly used formula auxiliary agent in the production and processing process of PVC leather, and has the functions of weakening the acting force among polymer molecules, thereby reducing the softening temperature, the melting temperature and the glass transition temperature of the polymer, increasing the fluidity of the polymer during processing, and improving the processability of the polymer and the flexibility of the PVC leather. The percentage content of the plasticizer in the PVC leather formula usually accounts for 40-50%, and the price of the plasticizer is relatively expensive, so that how to fully recover the plasticizer in the waste PVC leather becomes a research hotspot in the PVC leather product processing industry. In the prior art, a method for recovering the plasticizer in the PVC leather is reported, and the recovery and the reutilization of the plasticizer in the PVC leather are seriously restricted.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method for recovering a plasticizer in PVC leather. The recovery method is simple to operate and high in practicability, industrialization of plasticizer recovery is easy to realize, the plasticizer in the PVC leather can be efficiently recovered, the plasticizer resource is recycled, the waste of the resource is reduced, and good economic benefits are achieved; the method is particularly suitable for PVC leather taking a calcium zinc stabilizer as a stabilizing system, and can avoid heavy metal elements contained in the recovered plasticizer.

In order to achieve the purpose, the technical scheme of the invention is to design a method for recovering a plasticizer in PVC leather, which comprises the following steps:

s1: cutting PVC leather into fragments, placing the fragments in a container, and adding a certain amount of solvent until the liquid level of the solvent is over the PVC leather fragments;

s2: heating the solid-liquid mixture in the container to a certain temperature, stirring and leaching for a period of time, and condensing and refluxing the evaporated solvent in a condensing reflux device into the container;

s3: and filtering the solid-liquid mixture in the container, and distilling the filtrate under reduced pressure to remove the solvent to obtain the plasticizer.

Preferably, in the step S1, the solvent is one of an ethanol/n-hexane mixed system, an ethanol/n-heptane mixed system, an isopropanol/n-hexane mixed system, and an isopropanol/n-heptane mixed system.

In a more preferred embodiment, in the step S1, the components in the solvent are mixed at an equal volume ratio.

In the preferable technical scheme, in the step S2, the heating temperature is 70-100 ℃, and the stirring time is 4-6 h.

In a preferred embodiment, in step S3, the vacuum distillation conditions are: the temperature is 120-140 ℃, and the negative pressure value is 0.09-0.1 Mpa.

Further preferably, the method also comprises a step S4 of adding a certain amount of activated carbon into the plasticizer obtained in the step S3 for decolorization, and filtering to obtain a pure plasticizer product.

In a more preferable embodiment, in the step S4, the added mass of the activated carbon is 1 to 2% of the mass of the plasticizer.

The invention has the advantages and beneficial effects that:

1. the invention relates to a method for recycling plasticizer in PVC leather, which comprises the steps of slicing PVC leather, putting PVC car leather fragments into a solvent, heating and stirring, leaching for a period of time, filtering to obtain a leaching solution, and finally decompressing and steaming the leaching solution to remove the solvent to obtain the plasticizer. The recovery method is simple to operate and high in practicability, industrialization of plasticizer recovery is easy to realize, the plasticizer in the PVC leather can be efficiently recovered, the plasticizer resource is recycled, the waste of the resource is reduced, and good economic benefits are achieved; the method is particularly suitable for PVC leather taking a calcium zinc stabilizer as a stabilizing system, and can avoid heavy metal elements in the recovered plasticizer.

2. According to the method for recycling the plasticizer in the PVC leather, the used solvent is a mixed system formed by mixing two components with different polarities, and the plasticizer components with different polarities in the PVC leather can be fully extracted.

3. The invention discloses a method for recovering a plasticizer in PVC leather, which comprises the following steps of S2: the leaching process has dynamic stirring, and the solvent can fully dissolve the plasticizer extracted from and attached to the surface of the PVC product so as to ensure the total leaching efficiency: the container installs the condensation backward flow ware additional, realizes evaporating the condensation, the backward flow of solvent, prevents the potential safety hazard that the too high steam pressure of solvent brought in the high temperature leaching process, simultaneously, prevents that the solvent from volatilizing, revealing economic loss and the environmental problem who brings.

Detailed Description

The following further describes embodiments of the present invention with reference to examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The reagents used were: the ethanol, the normal hexane, the normal heptane and the isopropanol are analytically pure;

the PVC leather sample sheet comprises the following components: PVC resin 100phr, caCO ₃ 10phr of di (2-propylheptyl) phthalate (DPHP, plasticizer) 60phr and dioctyl sebacate (DOS, plasticizer) 30phr.

Example 1

The method for recovering the plasticizer in the PVC leather comprises the following operation steps:

s1: cutting 300g of PVC sample into fragments, placing the fragments into a 1000ml four-neck flask provided with an electric heating jacket, a stirrer and a reflux condenser, adding 300g of ethanol and n-hexane respectively, wherein the liquid level of a solvent completely submerges the fragments of PVC;

s2: heating to 79 ℃, stirring for 5 hours, and condensing the evaporated solvent through a reflux condenser to reflux into the four-neck flask;

s3: filtering the solid-liquid mixture in the four-mouth flask to obtain a leaching liquor containing the plasticizer, and carrying out reduced pressure distillation on the leaching liquor at the temperature of 130 ℃ and under the negative pressure of 0.9-1.0Mpa to remove ethanol and n-hexane so as to obtain 81.1g of a crude product of the plasticizer;

s4: 15g of activated carbon is added into the crude plasticizer product for decolorization and filtration to obtain 80.3g of pure plasticizer product, and the recovered pure plasticizer product contains 64.6% of DPHP (51.9 g) and 33.9% of DOS (27.2 g) through gas chromatography analysis, and the recovery efficiency of the plasticizer is (51.9 + 27.2) g/90 multiplied by 100% =87.9%.

Example 2

s2: heating to 70 ℃, stirring for 4h, and refluxing the evaporated solvent into the four-neck flask through a reflux condenser;

s3: filtering the solid-liquid mixture in the four-neck flask to obtain a leaching liquor containing the plasticizer, and carrying out reduced pressure distillation on the leaching liquor at the temperature of 120 ℃ and under the negative pressure of 0.9-1.0Mpa to remove ethanol and n-hexane so as to obtain 82.4g of a crude product of the plasticizer;

s4: 12g of activated carbon is added into the crude plasticizer for decolorization and filtration to obtain 81.6g of pure plasticizer, and the recovered pure plasticizer contains 63.8% of DPHP (52.1 g) and 34.8% of DOS (28.4 g) through gas chromatography analysis, and the recovery efficiency of the plasticizer is (52.1 + 28.4) g/90 multiplied by 100% =89.4%.

Example 3

s2: heating to 90 ℃, stirring for 6 hours, and refluxing the evaporated solvent into the four-neck flask through a reflux condenser;

s3: filtering the solid-liquid mixture in the four-mouth flask to obtain a leaching liquor containing the plasticizer, and carrying out reduced pressure distillation on the leaching liquor at the temperature of 130 ℃ and under the negative pressure of 0.9-1.0Mpa to remove ethanol and n-hexane so as to obtain 79.9g of a crude product of the plasticizer;

s4: 8g of activated carbon is added into the crude plasticizer product for decolorization and filtration to obtain 79.8g of pure plasticizer product, and the recovered pure plasticizer product contains 64.0% of DPHP (51.1 g) and 34.2% of DOS (27.3 g) through gas chromatography analysis, and the recovery efficiency of the plasticizer is (51.1 + 27.3) g/90 multiplied by 100% =87.1%.

Example 4

s1: cutting 300g of PVC sample into fragments, placing the fragments into a 1000ml four-neck flask provided with an electric heating jacket, a stirrer and a reflux condenser, adding 300g of ethanol and n-hexane respectively, wherein the liquid level of a solvent completely exceeds the fragments of PVC;

s2: heating to 90 ℃, stirring for 5 hours, and refluxing the evaporated solvent into the four-neck flask through a reflux condenser;

s3: filtering the solid-liquid mixture in the four-mouth flask to obtain a leaching liquor containing the plasticizer, and carrying out reduced pressure distillation on the leaching liquor at the temperature of 140 ℃ and under the negative pressure of 0.9-1.0Mpa to remove ethanol and n-hexane so as to obtain 82.5g of a crude product of the plasticizer;

s4: 16g of activated carbon is added into the crude plasticizer for decolorization and filtration to obtain 80.8g of pure plasticizer, and the recovered pure plasticizer contains 64.7 percent of DPHP (52.3 g), 33.97 percent of DOS (27.2 g) and the recovery efficiency of the plasticizer is (52.3 + 27.2) g/90 multiplied by 100% =88.3 percent by gas chromatography analysis.

TABLE 1 physicochemical Properties of the pure products of examples 1 to 4 in which the plasticizers were recovered

The experimental results show that: the plasticizers obtained by the method of the invention in the embodiments 1-4 have high quality and good purity, and the recovery rate of the plasticizer is more than 85%, thus realizing the purpose of the invention.

The method for recovering the plasticizer in the PVC leather is simple to operate, high in practicability, easy to realize industrialization of plasticizer recovery, capable of efficiently recovering the plasticizer in the PVC leather, capable of realizing recycling of plasticizer resources, capable of reducing resource waste and good in economic benefit; the method is especially suitable for PVC leather taking calcium zinc stabilizer as a stabilizing system, and can avoid heavy metal elements in the recovered plasticizer

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The method for recycling the plasticizer in the PVC leather is characterized by comprising the following steps:

s2: heating the solid-liquid mixture in the container to a certain temperature, stirring and leaching for a period of time, and condensing and refluxing the evaporated solvent in a condensing reflux device to the container;

2. The method for recycling the plasticizer in the PVC leather according to claim 1, wherein the solvent in the step S1 is one of an ethanol/n-hexane mixed system, an ethanol/n-heptane mixed system, an isopropanol/n-hexane mixed system, and an isopropanol/n-heptane mixed system.

3. The method for recycling the plasticizer in the PVC leather according to claim 2, wherein in the step S1, the components in the solvent are mixed in the same volume ratio.

4. The method for recycling the plasticizer in the PVC leather according to claim 1, wherein the heating temperature is 70-100 ℃ and the stirring time is 4-6 hours in the step S2.

5. The method for recycling plasticizer from PVC leather as claimed in claim 1, wherein in said step S3, the reduced pressure distillation condition is: the temperature is 120-140 ℃, and the negative pressure value is 0.09-0.1 Mpa.

6. The method for recycling the plasticizer in the PVC leather according to any one of claims 1 to 5, further comprising a step S4 of adding a certain amount of activated carbon into the plasticizer obtained in the step S3 for decolorization, and filtering to obtain a pure plasticizer.

7. The method for recycling the plasticizer in the PVC leather according to claim 6, wherein the added mass of the activated carbon in the step S4 is 1-2% of the mass of the plasticizer.