Purification method of polyphenylene sulfide

Abstract

The invention discloses a polyphenylene sulfide purification method, which comprises: cooling a polyphenylene sulfide product synthesized by a polymerization reaction, and carrying out solid-liquid separation to obtain a polyphenylene sulfide crude product; the method comprises the following steps: crushing a polyphenylene sulfide crude product, putting the crushed polyphenylene sulfide crude product into a mixed solution of lauroyl monoethanolamine and 1, 3-dimethyl-2-imidazolinone, stirring, and carrying out solid-liquid separation to obtain a solid component; and washing the solid components with deionized water, and drying to obtain purified polyphenylene sulfide. According to the method, the crude polyphenylene sulfide product is purified by adopting the mixed solution of the lauroyl monoethanolamine and the 1, 3-dimethyl-2-imidazolinone, so that impurities in the crude polyphenylene sulfide product can be efficiently removed, and then the crude polyphenylene sulfide product is washed by the deionized water, so that the impurities in the polyphenylene sulfide are better removed, and the purity of the prepared polyphenylene sulfide is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of purification of polyphenylene sulfide, and in particular to a method for purifying polyphenylene sulfide. Background Art

[0002] Polyphenylene sulfide (PPS) is a new type of high-performance thermoplastic resin with 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 chemicals.

[0003] At present, the production process of polyphenylene sulfide resin contains many impurities, most of which are chlorides, catalyst residues, polymerization mother liquor residues, incomplete polymers, etc. The large amount of impurities will affect the downstream companies' use of resin injection molding and fiber spinning, resulting in low finished product yields, poor mechanical properties, and unqualified product quality.

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

[0005] The object of the present invention is to provide a method for purifying polyphenylene sulfide, which can efficiently remove impurities in polyphenylene sulfide, improve the purity of polyphenylene sulfide, broaden its application field and improve product quality.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] A first aspect of the present invention provides a method for purifying polyphenylene sulfide, the method for purifying polyphenylene sulfide comprising the following steps:

[0008] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0009] (b) grinding the crude polyphenylene sulfide, and then placing it in a mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring it, and then performing solid-liquid separation to obtain a solid component;

[0010] (c) washing the solid component with deionized water and drying it to obtain purified polyphenylene sulfide.

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

[0012] Preferably, in the step (b), the crude polyphenylene sulfide is crushed to a particle size of not less than 200 meshes.

[0013] Preferably, in the step (b), the mass volume ratio of the crude polyphenylene sulfide to the mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:(10-15).

[0014] Preferably, in the step (b), the mass ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:(8-12).

[0015] Preferably, in step (b), the stirring speed is 150 to 250 rpm, and the stirring time is 20 to 40 min.

[0016] Preferably, in step (c), the washing comprises placing the solid component in deionized water and fully stirring and filtering to collect the solid matter, and repeating the above operation 1 to 5 times.

[0017] Preferably, the drying method is vacuum drying.

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

[0019] The present invention uses a mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone to purify a crude polyphenylene sulfide product, thereby efficiently removing impurities in the crude polyphenylene sulfide product. The crude polyphenylene sulfide product is then washed with deionized water to better remove impurities in the polyphenylene sulfide, thereby significantly improving the purity of the prepared polyphenylene sulfide. Specifically, the sodium ion content in the product is less than 5 ppm, the lithium ion content is less than 1 ppm, the chloride ion content is less than 5 ppm, and the oligomer content is less than 0.1%. DETAILED DESCRIPTION

[0020] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as 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 common meanings understood by those skilled in the art to which the present invention belongs.

[0022] An embodiment of the present invention provides a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0023] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0024] (b) grinding the crude polyphenylene sulfide, and then placing it in a mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring it, and then performing solid-liquid separation to obtain a solid component;

[0025] (c) washing the solid component with deionized water and drying it to obtain purified polyphenylene sulfide.

[0026] The present invention uses a mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone to purify a crude polyphenylene sulfide product, thereby efficiently removing impurities in the crude polyphenylene sulfide product. The crude polyphenylene sulfide product is then washed with deionized water to better remove impurities in the polyphenylene sulfide, thereby significantly improving the purity of the prepared polyphenylene sulfide. Specifically, the sodium ion content in the product is less than 5 ppm, the lithium ion content is less than 1 ppm, the chloride ion content is less than 5 ppm, and the oligomer content is less than 0.1%.

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

[0028] In one embodiment, in the step (b), the crude polyphenylene sulfide is crushed to a particle size of not less than 200 mesh.

[0029] In one embodiment, in the step (b), the mass volume ratio of the crude polyphenylene sulfide to the mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:(10-15).

[0030] In one embodiment, in the step (b), the mass ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:(8-12).

[0031] In one embodiment, in the step (b), the stirring speed is 150 to 250 rpm, and the stirring time is 20 to 40 min.

[0032] In one embodiment, in the step (c), the washing comprises placing the solid component in deionized water and fully stirring and filtering to collect the solid matter, and repeating the above operation 1 to 5 times.

[0033] In one embodiment, the drying method is vacuum drying.

[0034] The technical solution of the present invention is further described in detail below through specific embodiments.

[0035] Example 1

[0036] This embodiment is a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0037] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction to 80° C. and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0038] (b) crushing the crude polyphenylene sulfide and passing it through a 200-mesh sieve, then placing the sieve under the sieve in a mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring at 150 rpm for 40 minutes, and then performing solid-liquid separation to obtain a solid component, wherein the mass volume ratio of the crude polyphenylene sulfide to the mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:10; the mass volume ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:8;

[0039] (c) placing the solid component in deionized water and stirring it thoroughly, filtering it, collecting the solid, repeating the above operation once, and then drying it to obtain purified polyphenylene sulfide.

[0040] Example 2

[0041] This embodiment is a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0042] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction to 100° C. and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0043] (b) crushing the crude polyphenylene sulfide and passing it through a 200-mesh sieve, then placing the sieve under the sieve in a mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring at 250 rpm for 20 minutes, and then performing solid-liquid separation to obtain a solid component, wherein the mass volume ratio of the crude polyphenylene sulfide to the mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:15; the mass volume ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:12;

[0044] (c) placing the solid component in deionized water, stirring it thoroughly, filtering it, collecting the solid, repeating the above operation 5 times, and then drying it to obtain purified polyphenylene sulfide.

[0045] Example 3

[0046] This embodiment is a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0047] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction to 90° C. and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0048] (b) crushing the crude polyphenylene sulfide and passing it through a 200-mesh sieve, then placing the sieve under the sieve in a mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring at 200 rpm for 30 minutes, and then performing solid-liquid separation to obtain a solid component, wherein the mass volume ratio of the crude polyphenylene sulfide to the mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:12; the mass volume ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:10;

[0049] (c) placing the solid component in deionized water and stirring it thoroughly, filtering it, collecting the solid, repeating the above operation three times, and then drying it to obtain purified polyphenylene sulfide.

[0050] Comparative Example 1

[0051] This comparative example is a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0052] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction to 90° C. and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0053] (b) grinding the crude polyphenylene sulfide and passing it through a 200-mesh sieve, then placing the sieve under the sieve in 1,3-dimethyl-2-imidazolidinone and stirring at 200 rpm for 30 minutes, and then performing solid-liquid separation to obtain a solid component, wherein the mass volume ratio of the crude polyphenylene sulfide to the 1,3-dimethyl-2-imidazolidinone is 1:12;

[0054] (c) placing the solid component in deionized water and stirring it thoroughly, filtering it, collecting the solid, repeating the above operation three times, and then drying it to obtain purified polyphenylene sulfide.

[0055] Comparative Example 2

[0056] This comparative example is a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0057] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction to 90° C. and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0058] (b) crushing the crude polyphenylene sulfide and passing it through a 200-mesh sieve, then placing the sieve under the sieve in a mixture of polyethylene glycol and 1,3-dimethyl-2-imidazolidinone and stirring at 200 rpm for 30 minutes, and then performing solid-liquid separation to obtain a solid component, wherein the mass volume ratio of the crude polyphenylene sulfide to the mixture of polyethylene glycol and 1,3-dimethyl-2-imidazolidinone is 1:12; the mass volume ratio of polyethylene glycol to 1,3-dimethyl-2-imidazolidinone is 1:10;

[0059] (c) placing the solid component in deionized water and stirring it thoroughly, filtering it, collecting the solid, repeating the above operation three times, and then drying it to obtain purified polyphenylene sulfide.

[0060] Comparative Example 3

[0061] This comparative example is a method for purifying polyphenylene sulfide, and the method for purifying polyphenylene sulfide comprises the following steps:

[0062] (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction to 90° C. and performing solid-liquid separation to obtain a crude polyphenylene sulfide product;

[0063] (b) crushing the crude polyphenylene sulfide and passing it through a 200-mesh sieve, then placing the sieve under the sieve in a mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring at 200 rpm for 30 minutes, and then performing solid-liquid separation to obtain a solid component, wherein the mass volume ratio of the crude polyphenylene sulfide to the mixture of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:12; the mass volume ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:20;

[0064] (c) placing the solid component in deionized water and stirring it thoroughly, filtering it, collecting the solid, repeating the above operation three times, and then drying it to obtain purified polyphenylene sulfide.

[0065] Experimental example

[0066] The polyphenylene sulfide product synthesized by the sodium sulfide polymerization reaction was purified according to the purification methods of the polyphenylene sulfide in Examples 1 to 3 and Comparative Examples 1 to 3; then, the contents of sodium ions, chloride ions and oligomers in the purified polyphenylene sulfide were detected, and the detection results are shown in Table 1;

[0067] Table 1

[0068]

[0069]

[0070] From Table 1, we can see that:

[0071] Compared with the comparative example, the present application can better remove sodium ions, chloride ions and oligomers in the crude polyphenylene sulfide by specifically limiting the type and amount of the purification solvent, thereby improving the purity of the polyphenylene sulfide.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for purifying polyphenylene sulfide, characterized in that: The purification method of polyphenylene sulfide comprises the following steps: (a) cooling the polyphenylene sulfide product synthesized by the polymerization reaction and performing solid-liquid separation to obtain a crude polyphenylene sulfide product; (b) grinding the crude polyphenylene sulfide, and then placing it in a mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone and stirring it, and then performing solid-liquid separation to obtain a solid component; (c) washing the solid component with deionized water and drying it to obtain purified polyphenylene sulfide.

2. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: In the step (a), the temperature is lowered to 80-100°C.

3. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: In the step (b), the crude polyphenylene sulfide is crushed to a particle size of not less than 200 meshes.

4. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: In the step (b), the mass volume ratio of the crude polyphenylene sulfide to the mixed solution of lauroyl monoethanolamine and 1,3-dimethyl-2-imidazolidinone is 1:(10-15).

5. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: In the step (b), the mass ratio of lauroyl monoethanolamine to 1,3-dimethyl-2-imidazolidinone is 1:(8-12).

6. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: In the step (b), the stirring speed is 150 to 250 rpm, and the stirring time is 20 to 40 min.

7. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: In the step (c), the washing includes placing the solid component in deionized water and fully stirring and filtering to collect the solid matter, and repeating the above operation 1 to 5 times.

8. The method for purifying polyphenylene sulfide according to claim 1, characterized in that: The drying method is vacuum drying.

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