CN111100236A

CN111100236A - Method for removing VOC (volatile organic compounds) in vinyl acetate-ethylene copolymer emulsion

Info

Publication number: CN111100236A
Application number: CN201910967787.1A
Authority: CN
Inventors: 邱萱; 刘晶晶; 罗丽华; 吴江红; 杨坤
Original assignee: Chongqing Chuanwei Technology Co ltd; China Petroleum and Chemical Corp; Sinopec Chongqing Chuanwei Chemical Co Ltd
Current assignee: Chongqing Chuanwei Technology Co ltd; China Petroleum and Chemical Corp; Sinopec Chongqing Chuanwei Chemical Co Ltd
Priority date: 2018-10-25
Filing date: 2019-10-12
Publication date: 2020-05-05

Abstract

The invention belongs to the technical field of vinyl acetate-ethylene copolymer emulsion, and particularly relates to a method for removing VOC (volatile organic compounds) in vinyl acetate-ethylene copolymer emulsion, which comprises the following steps: and (3) distilling the vinyl acetate-ethylene copolymer emulsion obtained by the defoaming process under reduced pressure, then respectively adding the reducing agent solution and the oxidant solution into different tanks, and then treating at the normal pressure or less. The method improves the treatment efficiency of the residual monomer; not only is effective on unsaturated volatile matters, but also has better removal effect on saturated volatile matters; the high-temperature stability of the vinyl acetate-ethylene copolymer emulsion is not influenced; the VOC removal rate of the vinyl acetate-ethylene copolymer emulsion is high.

Description

Method for removing VOC (volatile organic compounds) in vinyl acetate-ethylene copolymer emulsion

Technical Field

The invention belongs to the technical field of vinyl acetate-ethylene copolymer emulsion, and particularly relates to a method for removing VOC (volatile organic compounds) in vinyl acetate-ethylene copolymer emulsion.

Background

Vinyl acetate-ethylene copolymer emulsion (VAE emulsion for short) is a water dispersion type emulsion with excellent performance and wide application, ethylene monomer is introduced into the emulsion as an internal plasticizer of a copolymer to soften a high molecular main chain, simultaneously, the glass transition temperature and the minimum film forming temperature of the emulsion are reduced due to the internal plasticizing effect of ethylene, and the polarity of acetyl of VAE molecules enables the copolymer to contain a large amount of fillers and various additives, so that the performance of the VAE emulsion can be improved, and therefore, the vinyl acetate-ethylene copolymer emulsion is widely applied to the fields of buildings, packaging, toys, home furnishings, automobiles, coatings, adhesives, textiles, electronic accessories and the like.

The VAE emulsion is formed by copolymerizing vinyl acetate and ethylene, and inevitably contains volatile organic compounds (VOC for short in English) such as benzene, aldehyde, ketone, acid, residual vinyl acetate monomer and the like. Most of these volatile organics are volatile, giving the emulsion a unique odor. With the enhancement of environmental awareness, people put forward more strict requirements on the content of volatile organic compounds in chemical products.

To reduce the VOC content in chemical products, CN101354213A removed the synthetic rubber solvent (i.e., volatile components) using a twin-screw vented extruder having 5 vacuum vents, each vent connected to a vacuum pump. CN101429044A adds amino-terminated polyether with high boiling point (250 ℃) into polyacrylate emulsion, and utilizes the reaction of the amino-terminated polyether with acrylate monomer to reduce the residual acrylate monomer in the polyacrylate emulsion. CN101544866A selects film forming base material (VAE emulsion) and a plurality of auxiliary products with low odor and ultra-low VOC to obtain the high-performance environment-friendly paint with odor purification and ultra-low VOC. CN104418959A adding 2-3 wt% organic solvent, 10-13 wt% water and 0.02-0.03 wt% initiator into VAE emulsion, high temperature (85-95 deg.C) distilling and nitrogen purging to make residual monomer removing rate in VAE emulsion reach 99%, and effectively reducing benzene content. CN103450409A reduced styrene-acrylic emulsion odor and VOC content (less than 500ppm) by adding natural olefins CN106397641A utilized hot nitrogen and steam to remove VOC from polymer powder. CN105199624A firstly shapes the carpet back glue, then changes the film-spraying proportion to improve the VOC of the car carpet. CN105169730A preheats the acrylic emulsion and removes VOC by hot steam and nitrogen. CN106883326A reduces the residual monomer content of polyvinyl acetate emulsion to 100ppm through two oxidation-reduction reactions, and effectively controls the content of impurities (acetone and tertiary n-butyl alcohol). US6365709B1, US6696519B2 disclose methods for treating ethylenically unsaturated monomers in aqueous polymers and the oxidizing and reducing agents used. EP0650977B1 first reduced the residual monomer to 1500-6000ppm by means of a redox initiator and then treated the residual monomer to 5-500ppm by physical means (steam, negative pressure). EP1024152B1 first reduced the VOC to 1500-6000ppm by means of redox initiators and then reduced the VOC to 15-50ppm by physical means (steam). US6096858B1 first removes residual monomers using a redox initiator and then reduces the VOC of the polymer to less than 100ppm using an inert gas.

The above-mentioned methods for reducing VOC of emulsions can be divided into the following three categories: firstly, a chemical method, which utilizes polymerization reaction to reduce the content of unsaturated monomers (mostly residual monomers) in emulsion; and secondly, a physical method, namely heating or negative pressure is utilized to enable the emulsion to be in a boiling state, and then gases such as air, water vapor, nitrogen and the like are utilized to remove VOC in the emulsion. And thirdly, continuously using a chemical method and a physical method. In the above patent, CN101429044A, CN103450409A, CN106883326A, US6365709B1 and US6696519B2 are chemical methods, and CN101354213A, CN106397641A and CN105169730A are physical methods; CN104418959A, EP0650977B1 and EP1024152B1 use both chemical and physical methods.

The above 3 methods all have corresponding defects, wherein the chemical method is only effective for unsaturated volatile matters (such as vinyl acetate) and has no removal effect for saturated volatile matters (such as methanol, n-butanol and ethyl acetate). The physical method has a removal effect on saturated volatile matters, but the emulsion needs to be in a boiling state for a long time to promote VOC volatilization, so that the use reaction is limited, and the method is only suitable for the emulsion with good high-temperature stability. In the continuous use of the chemical method and the physical method, the latter physical method reduces the chemical removal effect due to the removal of the oxidizing agent and the reducing agent, and in order to avoid this, either the chemical treatment time is prolonged as much as possible or the amounts of the oxidizing agent and the reducing agent are increased, thereby prolonging the process time and increasing the production cost.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for removing VOCs from vinyl acetate-ethylene copolymer emulsion, which has a good VOC removing effect, not only on unsaturated volatiles (such as vinyl acetate), but also on saturated volatiles (such as methanol, n-butanol, and ethyl acetate); and does not affect the high-temperature stability of the vinyl acetate-ethylene copolymer emulsion.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the method for removing VOC in the vinyl acetate-ethylene copolymer emulsion comprises the following steps: and (3) distilling the vinyl acetate-ethylene copolymer emulsion obtained by the defoaming process under reduced pressure, then respectively adding the reducing agent solution and the oxidant solution into different tanks, and then treating at the normal pressure or less.

The inventors have surprisingly found that the following steps are included: distilling the vinyl acetate-ethylene copolymer emulsion obtained by the defoaming process under reduced pressure, then respectively adding a reducing agent solution and an oxidant solution into different tanks, and then treating at the normal pressure or less; the method has good VOC removing effect, not only is effective on unsaturated volatile matters (such as vinyl acetate), but also has good VOC removing effect on saturated volatile matters (such as methanol, n-butanol and ethyl acetate).

Further, the reducing agent is 1-3 of sulfur compounds with the valence of sulfur atoms being-2-4, isoascorbate and tartrate.

Further, the reducing agent is 1-6 of zinc formaldehyde sulfoxylate, sodium erythorbate, sodium metabisulfite, sodium bisulfate and potassium tartrate.

Further, the mass ratio of the deionized water to the reducing agent in the reducing agent solution is as follows: 5-10:0.01-0.02.

Further, the dosage of the reducing agent solution is 0.01-0.02% of the mass of the vinyl acetate-ethylene copolymer emulsion as the reducing agent contained in the solution.

Further, the oxidant is 1-2 of inorganic peroxide and organic peroxide.

Further, the oxidant is 1-3 of persulfate, hydrogen peroxide and tert-butyl hydroperoxide.

Further, the mass ratio of the deionized water to the oxidant in the oxidant solution is as follows: 5-10:0.01-0.04.

Further, the dosage of the oxidant solution is 0.01-0.04% of the mass of the ethylene-vinyl acetate copolymer emulsion as the oxidant contained in the solution.

Further, the treatment under the normal pressure or less is vacuum distillation or normal pressure removal.

Further, the vacuum degree of the reduced pressure distillation is-0.06 to-0.08 MPa, and the time is 10-30 min.

Further, the vacuum degree of the reduced pressure distillation is-0.08 to-0.06 MPa, and the time is 10 to 20 min.

Further, the temperature of the normal pressure removal is 75-80 ℃, and the used gas is inert gas.

Further, the method comprises the steps of:

A. preparing raw materials: respectively preparing an oxidant solution and a reducing agent solution;

B. and (3) reduced pressure distillation: distilling the vinyl acetate-ethylene copolymer emulsion obtained from the defoaming process under reduced pressure, adjusting the pressure to normal pressure, and placing the vinyl acetate-ethylene copolymer emulsion in a storage tank;

c, removing: starting the storage tank to stir, simultaneously respectively dripping an oxidant solution and a reducing agent solution into the vinyl acetate-ethylene copolymer emulsion from different tanks, and filtering and discharging after 10-30min after the oxidant solution and the reducing agent solution are completely dripped;

D. and (3) reduced pressure distillation: and carrying out reduced pressure distillation on the vinyl acetate-ethylene copolymer emulsion from the storage tank, and then filtering and discharging.

Further, the method comprises the steps of:

c, removing: starting the storage tank to stir, simultaneously respectively dripping an oxidant solution and a reducing agent solution into the vinyl acetate-ethylene copolymer emulsion from different tanks, and filtering and discharging after 10min after the oxidant solution and the reducing agent solution are completely dripped;

D. removing under normal pressure: stirring the vinyl acetate-ethylene copolymer emulsion from the storage tank, heating to 75-80 ℃, blowing inert gas while stirring, filtering after 0.8-1.0h, and discharging.

The method can obviously reduce the VOC content in the vinyl acetate-ethylene copolymer emulsion.

The method can improve the treatment efficiency of residual monomers.

The invention has the beneficial effects that:

the method improves the treatment efficiency of residual monomers, and the treatment efficiency of vinyl acetate monomers reaches 99.69-99.81%.

The method for treating the vinyl acetate-ethylene copolymer emulsion has high VOC removal rate.

The method can greatly shorten the time consumption of the vinyl acetate-ethylene copolymer emulsion treatment process, thereby reducing the production cost.

The method is effective for unsaturated volatile (such as vinyl acetate) and saturated volatile (such as methanol, n-butanol, and ethyl acetate).

The method does not influence the high-temperature stability of the vinyl acetate-ethylene copolymer emulsion, and the high-temperature stability of the vinyl acetate-ethylene copolymer emulsion is not changed before and after the treatment by the method.

The vinyl acetate-ethylene copolymer emulsion obtained by the method basically achieves the odor-free degree and can meet the use requirements of high-grade customers.

Detailed Description

The examples are provided for better illustration of the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art should make insubstantial modifications and adaptations to the embodiments of the present invention in light of the above teachings and remain within the scope of the invention.

Example 1

The method for removing VOC in vinyl acetate-ethylene copolymer emulsion comprises the following specific steps:

A. preparing raw materials; 5 parts of deionized water and 0.02 part of ammonium persulfate are added into the tank A, and stirred for dissolution; adding 5 parts of deionized water and 0.01 part of sodium formaldehyde sulfoxylate into the tank B, and stirring for dissolving;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.06 MPa, vacuumizing for 10min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the ammonium persulfate solution from the tank A and the formaldehyde and sodium hyposulfite solution from the tank B into 100 parts of VAE emulsion, finishing dripping the ammonium persulfate solution, the formaldehyde and the sodium hyposulfite solution at the same time after 0.5h, and filtering and discharging the emulsion after 10 min;

D. and (3) reduced pressure distillation: and (3) putting the emulsion from the storage tank C into a decompression container again, setting the vacuum degree of the container to be 0.08MPa, vacuumizing for 30min, and then filtering and discharging.

Example 2

A. preparing raw materials: adding 7 parts of deionized water and 0.02 part of sodium erythorbate into the tank A, and stirring for dissolving; adding 7 parts of deionized water and 0.04 part of hydrogen peroxide into the tank B, and stirring for dissolving;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.07 MPa, vacuumizing for 15min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the sodium erythorbate solution from the tank A and the hydrogen peroxide solution from the tank B into 100 parts of VAE emulsion, dripping the sodium erythorbate solution and the hydrogen oxide solution simultaneously after 0.5h, filtering the emulsion after 10min, and discharging;

D. and (3) reduced pressure distillation: and (3) putting the emulsion from the storage tank C into a decompression container again, setting the vacuum degree of the container to be 0.08MPa, vacuumizing for 25min, and then filtering and discharging.

Example 3

A. preparing raw materials: adding 10 parts of deionized water and 0.02 part of potassium tartrate into the tank A, and stirring for dissolving; adding 10 parts of deionized water and 0.04 part of tert-butyl hydroperoxide into the tank B, and stirring for dissolving;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.08 MPa, vacuumizing for 20min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the potassium tartrate solution from the tank A and the tert-butyl hydroperoxide solution from the tank B into 100 parts of VAE emulsion, finishing dripping the potassium tartrate solution and the tert-butyl hydroperoxide solution after 0.5h, filtering the emulsion after 10min, and discharging;

D. and (3) reduced pressure distillation: and (3) putting the emulsion from the storage tank C into a decompression container again, setting the vacuum degree of the container to be 0.08MPa, vacuumizing for 20min, and then filtering and discharging.

Example 4

A. preparing raw materials: 6 parts of deionized water and 0.02 part of sodium persulfate are added into the tank A and stirred for dissolution; 6 parts of deionized water, 0.01 part of zinc isoascorbate and 0.01 part of magnesium tartrate are added into the tank B and stirred for dissolution;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.07 MPa, vacuumizing for min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping sodium persulfate solution from the tank A and dripping zinc isoascorbate-magnesium tartrate solution from the tank B into 100 parts of VAE emulsion, finishing dripping the sodium persulfate solution and the zinc isoascorbate-magnesium tartrate solution after 0.5h, filtering the emulsion after 10min, and discharging;

D. and (3) reduced pressure distillation: putting the emulsion from the storage tank C into a pressure reduction container again, setting the vacuum degree of the container to be-0.08 MPa, vacuumizing for 23min, and then filtering and discharging.

Example 5

A. preparing raw materials: adding 10 parts of deionized water, 0.02 part of ammonium persulfate and 0.01 part of hydrogen peroxide into the tank A, and stirring for dissolving; adding 10 parts of deionized water, 0.01 part of formaldehyde zinc sulfoxylate, 0.005 part of potassium tartrate and 0.005 part of sodium metabisulfite into the tank B, and stirring for dissolving;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping ammonium persulfate-hydrogen peroxide solution from the tank A and formaldehyde zinc sulfoxylate-potassium tartrate-sodium metabisulfite solution from the tank B into 100 parts of VAE emulsion, dripping the ammonium persulfate-hydrogen peroxide solution and the formaldehyde zinc sulfoxylate-potassium tartrate-sodium metabisulfite solution after 0.5h, filtering the emulsion after 10min, and discharging;

D. and (3) reduced pressure distillation: putting the emulsion from the storage tank C into a pressure reduction container again, setting the vacuum degree of the container to be-0.06 MPa, vacuumizing for 30min, and then filtering and discharging.

Example 6

A. preparing raw materials: adding 5 parts of deionized water and 0.02 part of tert-butyl hydroperoxide into the tank A, and stirring for dissolving; 5 parts of deionized water, 0.01 part of sodium formaldehyde sulfoxylate and 0.005 part of sodium erythorbate are added into the tank B and stirred for dissolution;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.06 MPa, vacuumizing for 20min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the tert-butyl hydroperoxide solution from the tank A and the sodium formaldehyde sulfoxylate-sodium isoascorbate solution from the tank B into 100 parts of VAE emulsion, dripping the tert-butyl hydroperoxide solution and the sodium formaldehyde sulfoxylate-sodium isoascorbate solution after 0.5h, filtering the emulsion after 10min, and discharging;

D. and (3) reduced pressure distillation: and (3) putting the emulsion from the storage tank C into a decompression container again, setting the vacuum degree of the container to be-0.07 MPa, vacuumizing for 20min, and then filtering and discharging.

Performance detection

The content of VOC, the content of unsaturated volatile matters such as vinyl acetate and the like, and the content of saturated volatile matters such as methanol, n-butanol and acetate in the VAE emulsion obtained by the defoaming process in examples 1 to 6 and the VAE emulsion obtained by the filtering and discharging in step D were measured, and the high-temperature stability and the odor of the VAE emulsion obtained by the defoaming process in examples 1 to 6 and the VAE emulsion obtained by the filtering and discharging in step D were measured, and the results are shown in table 1;

wherein, the VOC content is detected according to a determination method of the total volatile organic matter content in GB 18583-2008 indoor decoration and decoration material adhesive hazardous substance limit;

the content of vinyl acetate was measured in accordance with the method described in appendix A, which is a measure of the residual vinyl acetate in GB/T27573-2011 vinyl acetate-ethylene copolymer emulsion;

the content of the methanol is detected according to GB/T5009.266-2016 methanol in food determination;

detecting the content of the n-butanol according to a detection method of the content of the n-butanol in GB/T5009.48-2003 analytical method of the hygienic standards of distilled liquor and prepared liquor;

detecting the content of ethyl acetate according to a method for determining ethyl acetate in GB/T10345-2007 white spirit analysis method;

the detection method of the high-temperature stability comprises the following steps: after the mixture is placed for 2 weeks at the temperature of 50 ℃, observing whether the emulsion has agglomeration and caking phenomena, if the emulsion does not have agglomeration and caking, the high-temperature stability of the emulsion is normal;

the detection method of the smell comprises the following steps: and (4) sensory evaluation.

TABLE 1 Performance test results

As can be seen from table 1, the methods of examples 1 to 6 have VOC removal rates of 99.23% to 99.45% and vinyl acetate monomer removal rates of 99.69% to 99.81%, can significantly remove methanol, n-butanol and ethyl acetate from vinyl acetate-ethylene emulsion, and the high temperature stability of the vinyl acetate-ethylene copolymer emulsion is not changed; the vinyl acetate-ethylene copolymer emulsion obtained by the method has slight odor.

Therefore, the method disclosed by the invention has high treatment efficiency on VOC, is effective on unsaturated volatile matters (such as vinyl acetate), has a good removal effect on saturated volatile matters (such as methanol, n-butyl alcohol and ethyl acetate), does not influence the high-temperature stability of the vinyl acetate-ethylene copolymer emulsion, and the obtained vinyl acetate-ethylene copolymer emulsion basically achieves the odor purification degree.

Example 7

A. preparing raw materials: 5 parts of deionized water and 0.02 part of ammonium persulfate are added into the tank A, and stirred for dissolution; adding 5 parts of deionized water and 0.01 part of sodium formaldehyde sulfoxylate into the tank B, and stirring for dissolving;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the ammonium persulfate solution from the tank A and the formaldehyde and sodium sulfoxylate solution from the tank B into 100 parts of VAE emulsion, dripping the ammonium persulfate solution and the formaldehyde and sodium sulfoxylate solution simultaneously after 0.5h, and filtering and discharging the emulsion after 10 min;

D. removing under normal pressure: and (3) placing the emulsion from the storage tank C into the storage tank D, starting the storage tank D for stirring, opening a steam valve, opening a nitrogen valve at the bottom of the tank after the temperature of the emulsion is raised to 80 ℃, blowing nitrogen while stirring, closing the steam valve and the nitrogen valve after 1h, filtering and discharging.

Example 8

D. removing under normal pressure: and (3) placing the emulsion from the storage tank C into the storage tank D, starting the storage tank D for stirring, opening a steam valve, opening a nitrogen valve at the bottom of the tank after the temperature of the emulsion is raised to 77 ℃, blowing nitrogen while stirring, closing the steam valve and the nitrogen valve after 0.9h, filtering and discharging.

Example 9

D. removing under normal pressure: and (3) placing the emulsion from the storage tank C into the storage tank D, starting the storage tank D for stirring, opening a steam valve, opening a nitrogen valve at the bottom of the tank simultaneously after the temperature of the emulsion is raised to 78 ℃, blowing nitrogen while stirring, closing the steam valve and the nitrogen valve after 0.8h, filtering and discharging.

Example 10

A. preparing raw materials: adding 8 parts of deionized water and 0.01 part of sodium erythorbate into the tank A, and stirring for dissolving; adding 8 parts of deionized water, 0.01 part of hydrogen peroxide and 0.01 part of potassium persulfate into the tank B, and stirring for dissolving;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.07 MPa, vacuumizing for 18min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the sodium erythorbate solution from the tank A and the hydrogen peroxide-potassium persulfate solution from the tank B into 100 parts of VAE emulsion, dripping the sodium erythorbate solution and the hydrogen peroxide-potassium persulfate solution simultaneously after 0.5h, filtering the emulsion after 10min, and discharging;

D. removing under normal pressure: and (3) placing the emulsion from the storage tank C into the storage tank D, starting the storage tank D for stirring, opening a steam valve, opening a nitrogen valve at the bottom of the tank simultaneously after the temperature of the emulsion is increased to 79 ℃, blowing nitrogen while stirring, closing the steam valve and the nitrogen valve after 0.9h, filtering and discharging.

Example 11

A. preparing raw materials: adding 9 parts of deionized water, 0.005 part of formaldehyde zinc sulfoxylate, 0.005 part of sodium metabisulfite and 0.005 part of potassium tartrate into the tank A, and stirring for dissolving; 9 parts of deionized water, 0.01 part of hydrogen peroxide and 0.01 part of potassium persulfate are added into the tank B;

B. and (3) reduced pressure distillation: adding VAE emulsion obtained from the defoaming process into a container, setting the vacuum degree of the container to be-0.08 MPa, vacuumizing for 18min, raising the pressure of the container to normal pressure, and pumping the emulsion into a storage tank C;

C. removing: starting the storage tank C for stirring, respectively and simultaneously dripping the formaldehyde zinc sulfoxylate-sodium metabisulfite-potassium tartrate solution from the tank A and the hydrogen peroxide-potassium persulfate solution from the tank B into 100 parts of VAE emulsion, dripping the formaldehyde zinc sulfoxylate-sodium metabisulfite-potassium tartrate solution and the hydrogen peroxide-potassium persulfate solution after 0.5h, filtering the emulsion after 10min, and discharging;

Performance detection

The content of VOC, the content of unsaturated volatile matters such as vinyl acetate and the like, and the content of saturated volatile matters such as methanol, n-butanol and ethyl acetate in the VAE emulsion obtained by the defoaming process in examples 7 to 11 and the VAE emulsion obtained by the filtering and discharging in step D were measured, and the high-temperature stability and odor of the VAE emulsion obtained by the defoaming process in examples 7 to 11 and the VAE emulsion obtained by the filtering and discharging were measured, and the results are shown in table 2;

TABLE 2 Performance test results

As can be seen from table 2, the removal rate of VOC by the methods of examples 7 to 11 reaches 99.53% to 99.58%, the removal rate of vinyl acetate monomer reaches 99.60% to 99.63%, methanol, n-butanol and ethyl acetate in the vinyl acetate-ethylene emulsion can be significantly removed, and the high temperature stability of the vinyl acetate-ethylene copolymer emulsion is not changed before and after the treatment by the method; the vinyl acetate-ethylene copolymer emulsion obtained by the method has slight odor.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The method for removing VOC in the vinyl acetate-ethylene copolymer emulsion is characterized by comprising the following steps:

and (3) distilling the vinyl acetate-ethylene copolymer emulsion obtained by the defoaming process under reduced pressure, then respectively adding the reducing agent solution and the oxidant solution into different tanks, and then treating at the normal pressure or less.

2. The method according to claim 1, wherein the reducing agent is 1 to 3 of a sulfur compound having a valence of a sulfur atom of-2 to 4, an erythorbate salt and a tartrate salt.

3. The method of claim 2, wherein the reducing agent is 1-6 of zinc formaldehyde sulfoxylate, sodium erythorbate, sodium metabisulfite, sodium bisulfate, and potassium tartrate.

4. The method of claim 1, 2 or 3, wherein the mass ratio of deionized water to the reducing agent in the reducing agent solution is: 5-10:0.01-0.02.

5. The method according to claim 1, 2, 3 or 4, wherein the amount of the reducing agent solution is 0.01-0.02% of the mass of the vinyl acetate-ethylene copolymer emulsion as the reducing agent contained in the solution.

6. The method of claim 1, 2, 3, 4, or 5, wherein the oxidizing agent is 1-2 of an inorganic peroxide and an organic peroxide.

7. The method of claim 6, wherein the oxidizing agent is 1-3 of persulfate, hydrogen peroxide, and tert-butyl hydroperoxide.

8. The method of claim 1, 2, 3, 4, 5, 6 or 7, wherein the mass ratio of deionized water to oxidant in the oxidant solution is: 5-10:0.01-0.04.

9. The method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the oxidant solution is used in an amount of 0.01 to 0.04% by mass of the vinyl acetate-ethylene copolymer emulsion as the oxidant contained in the solution.

10. The process according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the treatment at ≤ atmospheric pressure is, in particular, distillation under reduced pressure or atmospheric pressure removal.

11. The method according to any one of claims 1 to 10, wherein the vacuum degree of the reduced pressure distillation is-0.06 to-0.08 MPa, and the time is 10 to 30 min.

12. The method according to claim 11, wherein the vacuum degree of the reduced pressure distillation is-0.08 to-0.06 MPa, and the time is 10 to 20 min.

13. A process according to claim 10, 11 or 12, characterized in that the temperature of the atmospheric removal is 75-80 ℃ and the gas used is an inert gas.

14. A method according to claim 10, 11, 12 or 13, comprising the steps of:

15. A method according to claim 10, 11, 12 or 13, characterized by the steps of: