Separation method of polyphenylene sulfide oligomer

Abstract

The invention discloses a polyphenylene sulfide oligomer separation method, which comprises: cooling a polyphenylene sulfide product synthesized by a sodium sulfide polymerization reaction, carrying out centrifugation, and carrying out solid-liquid separation to obtain polyphenylene sulfide and a mother solution; the preparation method comprises the following steps: putting polyphenylene sulfide into an aqueous solution of diethanol amine and 1, 3-dimethyl-2-imidazolinone for washing, and collecting a washing solution; mixing the washing solution and the mother solution, carrying out candle type filtration to obtain a filter cake, washing the filter cake with deionized water, and drying to obtain a polyphenylene sulfide oligomer; according to the method, the polyphenylene sulfide is washed in the aqueous solution of the diethanol amine and the 1, 3-dimethyl-2-imidazolinone, oligomer in the polyphenylene sulfide can be better washed out, meanwhile, the polyphenylene sulfide oligomer in the mother solution and the washing solution can be separated from other substances through the addition of the diethanol amine and the 1, 3-dimethyl-2-imidazolinone, and therefore the polyphenylene sulfide can be better washed out. The yield and the purity of the polyphenylene sulfide oligomer are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polyphenylene sulfide production, and particularly relates to a method for separating polyphenylene sulfide oligomers. Background Art

[0002] Polyphenylene sulfide (PPS) is a new type of high-performance thermoplastic resin, which has the advantages of high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, good thermal stability, excellent electrical properties, etc. It is widely used in the fields of electronics, automobiles, machinery and chemical industry.

[0003] Currently, a certain amount of small molecule oligomers will be produced in the production of polyphenylene sulfide resin, which can be used as polyphenylene sulfide for coating grade. However, in the domestic industry, the methods of storage tank stirring and washing, plate and frame pressure filtration for dehydration, and multi-stage storage tank washing are mostly adopted. The above methods consume a large amount of water, cause serious loss of oligomers, and due to the problems such as the small density of oligomers and the large viscosity in the swollen state, the washing effect of oligomers is poor, the residue is high, and the product yield is low.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers can fully extract the oligomers in the synthesis process of polyphenylene sulfide, improve the yield of polyphenylene sulfide oligomers, and can better remove the impurities in the oligomers and improve their purity.

[0006] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0007] The first aspect of the present invention provides a method for separating polyphenylene sulfide oligomers, and the method for separating polyphenylene sulfide oligomers comprises the following steps:

[0008] (a) After cooling the polyphenylene sulfide product synthesized by the sodium sulfide polymerization reaction, centrifugation and solid-liquid separation are carried out to obtain polyphenylene sulfide and mother liquor;

[0009] (b) The polyphenylene sulfide is washed in an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone, and the washing liquid is collected;

[0010] (c) The washing liquid and the mother liquor are mixed and subjected to candle filtration to obtain a filter cake, and then the filter cake is washed with deionized water and dried to obtain polyphenylene sulfide oligomers.

[0011] Preferably, in the step (a), the temperature is reduced to 80-100 °C.

[0012] Preferably, in the step (b), the washing temperature is 130-140 °C.

[0013] Preferably, in the step (b), the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1% - 5%, and the mass concentration of 1,3-dimethyl-2-imidazolidinone is 5% - 10%.

[0014] Preferably, in the step (b), the mass-to-volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1∶(10 - 15).

[0015] Preferably, in the step (c), the temperature of candle filtration is 60 - 80°C, and the filtration pore size is 150 mesh.

[0016] Preferably, in the step (c), washing with deionized water includes: placing the filter cake in deionized water, stirring, filtering, collecting the solid matter, and repeating the above operations 2 - 4 times.

[0017] Preferably, in the step (c), the drying method is vacuum drying.

[0018] Compared with the prior art, the beneficial effects of the present invention at least include:

[0019] By washing polyphenylene sulfide with an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone, the present invention can better wash out the oligomers in polyphenylene sulfide. At the same time, the addition of diethanolamine and 1,3-dimethyl-2-imidazolidinone is beneficial to the separation of polyphenylene sulfide oligomers from other substances in the mother liquor and washing liquid, improving the yield and purity of polyphenylene sulfide oligomers. Specific Embodiments

[0020] The following will describe in detail the embodiments of the technical solutions of the present invention in combination with the embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0021] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which the present invention belongs.

[0022] The embodiment of the present invention provides a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0023] (a) After cooling the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction, centrifuging and solid-liquid separation are carried out to obtain polyphenylene sulfide and the mother liquor;

[0024] (b) The polyphenylene sulfide is placed in an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone for washing, and the washing liquid is collected;

[0025] (c) Mix the washing liquid and the mother liquor and perform candle filtration to obtain a filter cake, and then wash the filter cake with deionized water and dry it to obtain the polyphenylene sulfide oligomer.

[0026] In the present invention, by washing polyphenylene sulfide in an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone, the oligomers in polyphenylene sulfide can be better washed out. At the same time, the addition of diethanolamine and 1,3-dimethyl-2-imidazolidinone is beneficial to the separation of polyphenylene sulfide oligomers and other substances in the mother liquor and the washing liquid, improving the yield and purity of the polyphenylene sulfide oligomer.

[0027] In one embodiment, in the step (a), the temperature is lowered to 80-100 °C.

[0028] In one embodiment, in the step (b), the washing temperature is 130-140 °C.

[0029] In one embodiment, in the step (b), the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1%-5%, and the mass concentration of 1,3-dimethyl-2-imidazolidinone is 5%-10%.

[0030] In one embodiment, in the step (b), the mass-volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:(10-15).

[0031] In one embodiment, in the step (c), the candle filtration temperature is 60-80 °C, and the filtration pore size is 150 mesh.

[0032] In one embodiment, in the step (c), washing with deionized water includes: placing the filter cake in deionized water, stirring, filtering, collecting the solid matter, and repeating the above operations 2-4 times.

[0033] In one embodiment, in the step (c), the drying method is vacuum drying.

[0034] The technical solution of the present invention will be further described in detail through specific examples below.

[0035] Example 1

[0036] This example is a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0037] (a) Cool the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction to 80 °C, then perform centrifugation and solid-liquid separation to obtain polyphenylene sulfide and a mother liquor;

[0038] (b) Place the polyphenylene sulfide in an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone and wash it at 130 °C. Collect the washing solution. Among them, the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1%, and the mass concentration of 1,3-dimethyl-2-imidazolidinone is 10%; the mass-to-volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:10;

[0039] (c) Mix the washing solution and the mother liquor and perform candle filtration at 80 °C with a filtration pore size of 150 mesh to obtain a filter cake. Then place the filter cake in deionized water, stir and filter, collect the solid matter, repeat the above operation 2 times, and dry it under vacuum to obtain the polyphenylene sulfide oligomer.

[0040] Example 2

[0041] This example is a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0042] (a) Cool the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction to 100 °C, then perform centrifugation and solid-liquid separation to obtain polyphenylene sulfide and the mother liquor;

[0043] (b) Place the polyphenylene sulfide in an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone and wash it at 130-140 °C. Collect the washing solution. Among them, the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 5%, and the mass concentration of 1,3-dimethyl-2-imidazolidinone is 5%; the mass-to-volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:15;

[0044] (c) Mix the washing solution and the mother liquor and perform candle filtration at 60 °C with a filtration pore size of 150 mesh to obtain a filter cake. Then place the filter cake in deionized water, stir and filter, collect the solid matter, repeat the above operation 4 times, and dry it under vacuum to obtain the polyphenylene sulfide oligomer.

[0045] Example 3

[0046] This example is a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0047] (a) Cool the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction to 90 °C, then perform centrifugation and solid-liquid separation to obtain polyphenylene sulfide and the mother liquor;

[0048] (b) Wash polyphenylene sulfide in an aqueous solution of diethanolamine and 1,3 - dimethyl - 2 - imidazolidinone at 130 °C, and collect the washing solution. Among them, the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3 - dimethyl - 2 - imidazolidinone is 2%, and the mass concentration of 1,3 - dimethyl - 2 - imidazolidinone is 8%; the mass - to - volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3 - dimethyl - 2 - imidazolidinone is 1∶12;

[0049] (c) Mix the washing solution and the mother liquor and perform candle - type filtration at 70 °C with a filtration pore size of 150 mesh to obtain a filter cake. Then place the filter cake in deionized water, stir and filter, collect the solid matter, repeat the above operation 3 times, and dry it under vacuum to obtain the polyphenylene sulfide oligomer.

[0050] Comparative Example 1

[0051] This comparative example is a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0052] (a) Cool the polyphenylene sulfide product synthesized by the sodium sulfide - based polymerization reaction to 90 °C, then perform centrifugation and solid - liquid separation to obtain polyphenylene sulfide and the mother liquor;

[0053] (b) Wash polyphenylene sulfide in an aqueous solution of 1,3 - dimethyl - 2 - imidazolidinone at 130 °C, and collect the washing solution. Among them, the mass concentration of 1,3 - dimethyl - 2 - imidazolidinone in the aqueous solution of 1,3 - dimethyl - 2 - imidazolidinone is 10%; the mass - to - volume ratio of polyphenylene sulfide to the aqueous solution of 1,3 - dimethyl - 2 - imidazolidinone is 1∶12;

[0054] (c) Mix the washing solution and the mother liquor and perform candle - type filtration at 70 °C with a filtration pore size of 150 mesh to obtain a filter cake. Then place the filter cake in deionized water, stir and filter, collect the solid matter, repeat the above operation 3 times, and dry it under vacuum to obtain the polyphenylene sulfide oligomer.

[0055] Comparative Example 2

[0056] This comparative example is a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0057] (a) Cool the polyphenylene sulfide product synthesized by the sodium sulfide - based polymerization reaction to 90 °C, then perform centrifugation and solid - liquid separation to obtain polyphenylene sulfide and the mother liquor;

[0058] (b) Wash polyphenylene sulfide in an aqueous solution of diethanolamine at 130 °C, and collect the washing solution. Among them, the mass concentration of diethanolamine in the aqueous solution of diethanolamine is 10%; the mass - to - volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine is 1∶12;

[0059] (c) Mix the washing liquid and the mother liquor and perform candle filtration at 70 °C with a filtration pore size of 150 mesh to obtain a filter cake. Then, place the filter cake in deionized water, stir and filter, collect the solid matter, repeat the above operations 3 times, and perform vacuum drying to obtain the polyphenylene sulfide oligomer.

[0060] Comparative Example 3

[0061] This comparative example is a method for separating polyphenylene sulfide oligomers. The method for separating polyphenylene sulfide oligomers includes the following steps:

[0062] (a) Cool the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction to 90 °C, then perform centrifugation and solid-liquid separation to obtain polyphenylene sulfide and the mother liquor;

[0063] (b) Place the polyphenylene sulfide in an aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone and wash at 90 °C, collect the washing liquid. Among them, the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 2%, and the mass concentration of 1,3-dimethyl-2-imidazolidinone is 8%; the mass-volume ratio of polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:12;

[0064] (c) Mix the washing liquid and the mother liquor and perform candle filtration at 70 °C with a filtration pore size of 150 mesh to obtain a filter cake. Then, place the filter cake in deionized water, stir and filter, collect the solid matter, repeat the above operations 3 times, and perform vacuum drying to obtain the polyphenylene sulfide oligomer.

[0065] Experimental Example

[0066] Separate the oligomers from 200 ml of the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction according to the methods for separating polyphenylene sulfide oligomers in Example 3 and Comparative Examples 1-3 respectively; then, detect the sodium ion content in the separated polyphenylene sulfide oligomers, and weigh the mass of the polyphenylene sulfide oligomers. Based on the mass of the polyphenylene sulfide oligomers in Example 3, calculate the relative changes of the polyphenylene sulfide oligomers in Examples 1-2 and Comparative Examples 1-3. The results are shown in Table 1;

[0067] Table 1

[0068] Group Sodium ion content Relative amount of oligomer Example 1 6.8 ppm 99.7％ Example 2 7.1 ppm 101.2％ Example 3 6.3 ppm 100％ Comparative Example 1 46.9 ppm 86.3％ Comparative Example 2 57.2 ppm 82.6％ Comparative Example 3 8.1 ppm 93.7％

[0069] As can be seen from Table 1:

[0070] Compared with the comparative examples, the method for separating polyphenylene sulfide oligomers in the examples of the present application can better extract the polyphenylene sulfide oligomers in the synthesis feed liquid through the selection of diethanolamine and 1,3-dimethyl-2-imidazolidinone, and improve the purity of the polyphenylene sulfide oligomers.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method for separating polyphenylene sulfide oligomers, characterized in that, The method for separating the polyphenylene sulfide oligomer comprises the following steps: (a) After cooling the polyphenylene sulfide product synthesized by the sodium sulfide method polymerization reaction, centrifuging and solid-liquid separation are carried out to obtain polyphenylene sulfide and mother liquor; (b) The polyphenylene sulfide is placed in diethanolamine and an aqueous solution of 1,3-dimethyl-2-imidazolidinone for washing, and the washing liquid is collected; (c) The washing liquid and the mother liquor are mixed and subjected to candle filtration to obtain a filter cake, and then the filter cake is washed with deionized water and dried to obtain the polyphenylene sulfide oligomer.

2. The purification method of polyphenylene sulfide according to claim 1, wherein In the step (a), the temperature is cooled to 80-100 °C.

3. The purification method of polyphenylene sulfide according to claim 1, wherein In the step (b), the washing temperature is 130-140 °C.

4. The purification method of polyphenylene sulfide according to claim 1, characterized in that, In the step (b), the mass concentration of diethanolamine in the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1%-5%, and the mass concentration of 1,3-dimethyl-2-imidazolidinone is 5%-10%.

5. The purification method of polyphenylene sulfide according to claim 1, characterized in that, In the step (b), the mass-volume ratio of the polyphenylene sulfide to the aqueous solution of diethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:(10-15).

6. The purification method of polyphenylene sulfide according to claim 1, wherein In the step (c), the candle filtration temperature is 60-80 °C, and the filtration pore size is 150 mesh.

7. The purification method of polyphenylene sulfide according to claim 1, wherein In the step (c), the washing with deionized water includes: placing the filter cake in deionized water for stirring and filtration, collecting the solid matter, and repeating the above operations 2-4 times.

8. The purification method of polyphenylene sulfide according to claim 1, wherein In the step (c), the drying method is vacuum drying.