CN115806670B - A combined post-treatment purification method for polyphenylene sulfide - Google Patents

Abstract

The invention belongs to the field of polyphenylene sulfide resin purification, and particularly provides a polyphenylene sulfide resin post-treatment purification method which comprises the steps of heating and suction filtering a crude product of the polyphenylene sulfide resin, washing and suction filtering with deionized water, drying a filter cake after washing, then putting the filter cake into a ball mill, adding an ethanol solution with the mass concentration of 60% -95%, grinding by zirconia beads with the particle size range of 0.6-1.8mm, separating out the resin, heating and stirring the resin with deionized water for multiple times, washing the resin while the resin is hot, suction filtering the resin, and drying the resin to obtain the high-purity polyphenylene sulfide resin.

Description

A combined post-treatment purification method for polyphenylene sulfide

Technical Field

The invention belongs to the field of polyphenylene sulfide resin purification, and in particular relates to a polyphenylene sulfide resin post-processing purification method.

Background technique

Polyphenylene sulfide (PPS) is one of the most important and common resins among polyarylene sulfides. Due to the rigidity and heat resistance of the benzene ring structure and the stability of the chemical bond between the benzene ring and sulfur, polyphenylene sulfide molecules are endowed with highly stable chemical bond characteristics, and have excellent thermal stability, chemical stability, dimensional stability and electrical properties.

According to relevant literature reports, there are many reaction routes for synthesizing polyphenylene sulfide, but the sodium sulfide solution polycondensation method is mainly used in industry to produce polyphenylene sulfide resin. In the process of synthesizing polyphenylene sulfide resin, sodium chloride is also generated, and other inorganic salt additives are often added. When sodium sulfide and p-dichlorobenzene undergo polycondensation reaction in a solvent system, inorganic salts will also dissolve in the organic solvent at the same time as the product. The final polyphenylene sulfide resin is wrapped with a large amount of inorganic salts, organic solvents, oligomers, etc. These impurities will affect the mechanical properties, thermal stability, electrical insulation and other properties of the resin, and indirectly affect the application of polyphenylene sulfide resin in the fields of national defense, aerospace, electronic packaging components, etc.

Patent CN112940255A discloses a purification process of polyphenylene sulfide resin, wherein the polyphenylene sulfide resin is synthesized by using sodium sulfide and p-dichlorobenzene as raw materials and N-methyl-2-pyrrolidone as solvent, filtering and separating the separated filter cake containing organic impurities, sodium chloride, NMP solvent, and water, washing and drying, adding a mixed solvent, raising the temperature of the solid-liquid system to below the boiling point of the mixed solvent, dissolving the polyphenylene sulfide resin in the mixed solvent, and adding deionized water after keeping the temperature for a certain period of time to crystallize the polyphenylene sulfide, and after solid-liquid separation, extracting the high boiling point organic solvent in the mixed solvent with a low boiling point solvent, and washing the polyphenylene sulfide resin with deionized water to obtain a high-purity polyphenylene sulfide resin. However, this method is cumbersome to operate and is not suitable for industrial production.

Patent CN102731785A discloses a method for purifying polyphenylene sulfide, and the steps are as follows: (1) acid-base neutralization: cool the polyphenylene sulfide resin generated by the polymerization reaction, add acid, control the pH to 3-4, and react for a period of time under stirring; (2) solid-liquid separation: cool the reaction product obtained in step (1) and separate the solid and liquid to obtain a polyphenylene sulfide solid; (3) solvent washing: add an organic solvent to the polyphenylene sulfide solid obtained in (2), and wash it under stirring; (4) steam distillation and water washing: steam distill the polyphenylene sulfide obtained in step (3) under negative pressure conditions, and recover the organic solvent remaining in the polyphenylene sulfide solid particles during the distillation process; when the organic solvent content is less than 1%, wash the polyphenylene sulfide with steam condensed water at 75°C to 85°C; (5) drying and packaging: separate, dry and package the polyphenylene sulfide obtained in step (4). The above method is based on steam distillation under negative pressure conditions, which has high requirements and is not suitable for industrial production.

Summary of the invention

In order to remove impurities contained in polyphenylene sulfide resin as much as possible and obtain high-purity polyphenylene sulfide resin, the present invention provides a polyphenylene sulfide resin post-treatment purification method, which has the characteristics of simplicity and high efficiency.

In order to achieve the purpose of the present invention, the technical solution adopted is:

A post-treatment purification method for polyphenylene sulfide resin comprises the following steps:

The crude polyphenylene sulfide resin product is heated and filtered, washed and filtered with deionized water (the filter cake contains impurities such as solvent and sodium chloride. The filter cake is washed and filtered with deionized water to remove some impurities in the resin, but a small amount of impurities such as sodium chloride are still wrapped inside the resin, which will affect the performance of polyphenylene sulfide during use), the washed filter cake is dried and then put into a ball mill, and ethanol solution is added, and it is ground with zirconium oxide beads of different particle sizes, and then the resin is separated, and then it is heated and stirred with deionized water for multiple washings and filtered while hot, and then dried to obtain high-purity polyphenylene sulfide resin.

Add ethanol solution and grind together. During the grinding process, some impurities (part of the salt and the solvent) are more easily dissolved in the ethanol solution with rapid rotation. In this case, the maximum amount of impurities can be removed with the minimum amount of deionized water.

Furthermore, the method for obtaining the crude product of polyphenylene sulfide resin includes: using industrial anhydrous sodium sulfide and industrial p-dichlorobenzene as raw materials, lithium chloride as a catalyst, and N-methylpyrrolidone (NMP) as a solvent to synthesize polyphenylene sulfide resin, wherein the molecular weight of the polyphenylene sulfide resin is 42,000-48,000.

Furthermore, the crude polyphenylene sulfide resin product is heated to a filtration temperature of 80° C. or higher and maintained for more than 10 minutes before filtration while hot. The solid obtained by filtration has a separation rate of 90%, that is, more than 90% of the polar solvent is separated.

Furthermore, the ground resin is heated and stirred for multiple washing for 2-3 times, the heating temperature is above 80° C. and maintained for more than 10 minutes before being filtered while hot.

Furthermore, the particle size range of the zirconia balls is between 0.6-12 mm, which can better promote the dissolution effect of the ethanol solution on impurities during the grinding process. The preferred particle size range is between 0.6-1.8 mm. The filter cake loading amount is 50%-80% of the ball mill volume, and the preferred loading amount is 66% of the ball mill volume.

Furthermore, the grinding machine is a refrigerated planetary ball mill, and the working mode is that four tanks run simultaneously; the speed of the refrigerated planetary ball mill has an orbital range of 180-290r/min, preferably an orbital range of 290r/min, and an autorotation range of 360-580r/min, preferably an autorotation range of 580r/min.

Furthermore, the concentration of the ethanol solution is between 60% and 95%, and preferably between 70% and 95%.

Furthermore, the drying method is to dry at 80-100° C. for 8-10 hours.

The invention further combines grinding with ethanol solution dissolution and washing on the basis of hot filtration and heated washing filtration of the crude product to achieve effective removal of chloride ions and organic solvents. Compared with the prior art, the invention has the characteristics of simplicity and high efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow chart of the preparation and post-treatment of polyphenylene sulfide in an embodiment of the present invention.

Detailed ways

The present invention will be further described below by way of examples, but the content and scope of the present invention are not limited thereby.

The method for obtaining the polyphenylene sulfide resin in the following examples and comparative examples includes: using industrial anhydrous sodium sulfide and industrial p-dichlorobenzene as raw materials, lithium chloride as a catalyst, and N-methylpyrrolidone (NMP) as a solvent to synthesize the polyphenylene sulfide resin, and the molecular weight of the polyphenylene sulfide resin is 42,000-48,000.

Example 1

(1) After the polyphenylene sulfide polycondensation reaction is completed, the polyphenylene sulfide resin mixture is heated to above 80° C. and maintained for about 10 minutes and then filtered while hot. The solid obtained by filtration has a separation rate of 90%, that is, more than 90% of the polar solvent is separated. The filter cake solid is set aside and the filtrate is recovered;

(2) The solid components of the filter cake in (1) are washed with deionized water in an amount of 2 L and heated to above 80° C. and maintained for about 10 minutes, and then filtered while hot. This is repeated 2-3 times, and the filter cake solids are dried for later use;

(3) Take out 10 g of the solid component of the filter cake dried in (2) and put it into a 500 ml ball mill, add 100 ml of 95% ethanol solution, put in zirconium oxide balls with a particle size of 0.6-0.8 mm, and the total sample volume is 66% of the volume of the ball mill. The speed of the ball mill is set to revolution: 290 r/min, rotation: 580 r/min, grind for 10 minutes and then separate, and the separated resin is set aside;

(4) The resin separated in (3) was heated and stirred with deionized water (2 L). The water amount was heated to above 80° C. and maintained for about 10 minutes. The resin was then filtered while hot. This process was repeated 2-3 times. The filter cake was set aside for use. The ^Cl- content was detected to be 0.01%.

(5) placing the filter cake solid in (4) into an oven and drying at 80-100° C. for 8-10 hours;

(6) Weigh a certain amount of the dried polyphenylene sulfide resin prepared in (5), and place it in a muffle furnace for calcination. The temperature of the muffle furnace is set as follows: from room temperature to 800° C. for 1 hour, maintained at 800° C. for 8 hours, and then reduced from 800° C. to room temperature for 3 hours. The resin is then taken out and the ash content is measured to be 0.08%.

Example 2

(1) After the polyphenylene sulfide polycondensation reaction is completed, the polyphenylene sulfide resin mixture is heated to above 80° C. and maintained for about 10 minutes and then filtered while hot. The solid obtained by filtration has a separation rate of 90%, that is, more than 90% of the polar solvent is separated. The filter cake solid is set aside and the filtrate is recovered;

(2) The solid components of the filter cake in (1) are washed with deionized water in an amount of 2 L and heated to above 80° C. and maintained for about 10 minutes, and then filtered while hot. This is repeated 2-3 times, and the filter cake solids are dried for later use;

(3) Take out 10 g of the solid component of the filter cake dried in (2) and put it into a 500 ml ball mill, add 100 ml of 95% ethanol solution, put in zirconium oxide balls with a particle size of 0.8-1.0 mm, and the total sample volume is 66% of the volume of the ball mill. The speed of the ball mill is set to revolution: 290 r/min, rotation: 580 r/min, grind for 10 minutes and then separate, and the separated resin is set aside;

(4) The resin separated in (3) was heated and stirred with deionized water (2 L). The water amount was heated to above 80° C. and maintained for about 10 minutes. Then, it was filtered while hot. This was repeated 2-3 times. The filter cake was set aside for use. The ^Cl- content was detected to be 0.05%;

(5) placing the filter cake solid in (4) into an oven and drying at 80-100° C. for 8-10 hours;

(6) Weigh a certain amount of the dried polyphenylene sulfide resin prepared in (5), and place it in a muffle furnace for calcination. The temperature of the muffle furnace is set as follows: from room temperature to 800° C. for 1 hour, maintained at 800° C. for 8 hours, and then reduced from 800° C. to room temperature for 3 hours. The resin is then taken out and the ash content is measured to be 0.12%.

Example 3

(1) After the polyphenylene sulfide polycondensation reaction is completed, the polyphenylene sulfide resin mixture is heated to above 80° C. and maintained for about 10 minutes and then filtered while hot. The solid obtained by filtration has a separation rate of 90%, that is, more than 90% of the polar solvent is separated. The filter cake solid is set aside and the filtrate is recovered;

(2) The solid components of the filter cake in (1) are washed with deionized water in an amount of 2 L and heated to above 80° C. and maintained for about 10 minutes, and then filtered while hot. This is repeated 2-3 times, and the filter cake solids are dried for later use;

(3) Take out 10 g of the solid component of the filter cake dried in (2) and put it into a 500 ml ball mill, add 100 ml of 95% ethanol solution, put in zirconium oxide balls with a particle size of 1.0-1.2 mm, and the total sample volume is 66% of the volume of the ball mill. The speed of the ball mill is set to revolution: 290 r/min, rotation: 580 r/min, grind for 10 minutes and then separate, and the separated resin is set aside;

(4) The resin separated in (3) was heated and stirred with deionized water (2 L). The water amount was heated to above 80° C. and maintained for about 10 minutes. The resin was then filtered while hot. This process was repeated 2-3 times. The filter cake was solid and set aside. The ^Cl- content was detected to be 0.09%.

(5) placing the filter cake solid in (4) into an oven and drying at 80-100° C. for 8-10 hours;

(6) Weigh a certain amount of the dried polyphenylene sulfide resin in (5), put it into a muffle furnace for calcination, and set the temperature of the muffle furnace: raise the temperature from room temperature to 800°C for 1 hour, maintain 800°C for 8 hours, and reduce the temperature from 800°C to room temperature for 3 hours. Then take it out and weigh the ash content, which is 0.16%.

Example 4

The method is the same as that of Example 1, except that:

The particle size of zirconia balls was changed to 1.2-1.4mm;

According to this operating condition, the ^Cl- content is 0.13% and the ash weight is 0.20%.

Example 5

The method is the same as that of Example 1, except that:

The particle size of zirconia balls was changed to 1.4-1.6mm;

According to this operating condition, the ^Cl- content was detected to be 0.17% and the ash content was weighed to be 0.24%.

Example 6

The method is the same as that of Example 1, except that:

The particle size of zirconia balls was changed to 1.6-1.8mm;

According to this operating condition, the ^Cl- content was detected to be 0.21% and the ash content was weighed to be 0.28%.

Example 7

The method is the same as that of Example 1, except that:

The ethanol concentration was changed to 90%;

According to this operating condition, the ^Cl- content is 0.03% and the ash weight is 0.10%.

Example 8

The method is the same as that of Example 1, except that:

The ethanol concentration was changed to 85%;

According to this operating condition, the ^Cl- content is 0.05% and the ash weight is 0.12%.

Example 9

The method is the same as that of Example 1, except that:

The ethanol concentration was changed to 80%;

According to this operating condition, the ^Cl- content was detected to be 0.07% and the ash content was weighed to be 0.14%.

Example 10

The method is the same as that of Example 1, except that:

The ethanol concentration was changed to 75%;

According to this operating condition, the ^Cl- content was detected to be 0.09% and the ash content was weighed to be 0.16%.

Embodiment 11

The method is the same as that of Example 1, except that:

The ethanol concentration was changed to 70%;

According to this operating condition, the ^Cl- content was detected to be 0.11% and the ash content was weighed to be 0.18%.

Comparative Example 1

The method is the same as that of Example 1, except that:

The concentration of ethanol solution was changed to 50%;

The particle size of zirconia balls was changed to 0.6-0.8mm;

Under this operating condition, the ^Cl- content was detected to be 2.3%; the ash content was weighed to be 3.5%.

Comparative Example 2

The method is the same as that of Example 1, except that:

The concentration of ethanol solution was changed to 60%;

The particle size of zirconia balls was changed to 0.8-1.0mm;

Under this operating condition, the ^Cl- content was detected to be 2.5%; the ash weight was weighed to be 3.8%.

Comparative Example 3

The method is the same as that of Example 1, except that:

The concentration of ethanol solution was changed to 95%;

The particle size of zirconia balls was changed to 2 mm;

Under this operating condition, the ^Cl- content was detected to be 2.8%; the ash content was weighed to be 4.0%.

Comparative Example 4

The method is the same as that of Example 1, except that:

The concentration of ethanol solution was changed to 90%;

The particle size of zirconia balls was changed to 3mm;

According to this operating condition, the ^Cl- content was detected to be 3.0%; the ash content was weighed to be 4.2%.

Comparative Example 5

The method is the same as that of Example 5, except that:

The speed of the ball mill is set to revolution: 100r/min, rotation: 200r/min

Under this operating condition, the ^Cl- content was detected to be 2.4%; the ash weight was weighed to be 3.6%.

Comparative Example 6

The method is the same as that of Example 6, except that:

The speed of the ball mill is set to revolution: 50r/min, rotation: 100r/min

Under this operating condition, the ^Cl- content was detected to be 2.9%; the ash content was weighed to be 4.1%.

Comparative Example 7

The processing and test data of polyphenylene sulfide resin are shown in Table 1:

(1) After the polyphenylene sulfide polycondensation reaction is completed, the polyphenylene sulfide resin mixture is heated to above 80° C. and maintained for about 10 minutes and then filtered while hot. The solid obtained by filtration has a separation rate of 90%, that is, more than 90% of the polar solvent is separated. The filter cake solid is set aside and the filtrate is recovered;

(2) The solid components of the filter cake in (1) were washed with deionized water in an amount of 2 L and heated to above 80° C. and maintained for about 10 minutes, and then filtered while hot. This was repeated 2-3 times. The filter cake solid components were set aside for use. The ^Cl- content was detected to be 3.8%;

(3) placing the filter cake solid in (2) into an oven and drying at 80-100° C. for 8-10 hours;

(4) Weigh a certain amount of the dried polyphenylene sulfide resin in (3), put it into a muffle furnace for calcination, and set the temperature of the muffle furnace: raise the temperature from room temperature to 800°C for 1 hour, maintain 800°C for 8 hours, and reduce the temperature from 800°C to room temperature for 3 hours. Then take it out and weigh the ash content, which is 5%.

Table 1

sample Ash content (%) Cl ^- content (%) Homemade polyphenylene sulfide resin 5 3.8

Through the post-treatment method of the present invention, a polyphenylene sulfide resin with low salt and low impurities can be obtained. The test data are summarized in Table 2 and Table 3 below:

Table 2

table 3

The purification method of the present invention can improve the purity of polyphenylene sulfide, thereby improving the performance of subsequent processing of polyphenylene sulfide.

The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims (6)

1. A polyphenylene sulfide resin post-treatment purification method is characterized in that: heating and suction-filtering a polyphenylene sulfide resin crude product, washing and suction-filtering with deionized water, drying a filter cake after washing, putting into a ball mill, adding an ethanol solution with the mass concentration of 70% -95%, grinding by zirconia beads with the particle size range of 0.6-1.8 mm, separating out resin, heating and stirring with deionized water for multiple times, washing and suction-filtering while hot, and drying to obtain high-purity polyphenylene sulfide resin;

the resin is heated, stirred and washed for a plurality of times for 2 to 3 times after grinding, the heating temperature is more than 80 ℃ and maintained for more than 10 minutes, and then the resin is filtered while the resin is hot;

the grinding machine is a refrigeration planetary ball mill, and the working mode is that four tanks are operated simultaneously; the revolution range is 180-290r/min, and the rotation range is 360-580 r/min.

2. The polyphenylene sulfide resin post-treatment purification method according to claim 1, wherein: the method for obtaining the polyphenylene sulfide resin crude product comprises the following steps: the industrial anhydrous sodium sulfide and industrial paradichlorobenzene are used as raw materials, lithium chloride is used as a catalyst, N-methylpyrrolidone is used as a solvent to synthesize the polyphenylene sulfide resin, and the molecular weight of the polyphenylene sulfide resin is 4.2-4.8 ten thousand.

3. The polyphenylene sulfide resin post-treatment purification method according to claim 1, wherein: the temperature of the heating and suction filtration of the polyphenylene sulfide resin crude product is more than 80 ℃ and maintained for more than 10 minutes, and then the suction filtration is carried out while the polyphenylene sulfide resin crude product is hot, and the separation rate of the solid obtained by the suction filtration reaches 90 percent.

4. The polyphenylene sulfide resin post-treatment purification method according to claim 1, wherein: the sample loading amount of the filter cake is 50% -80% of the volume of the ball milling tank.

5. The polyphenylene sulfide resin post-treatment purification method according to claim 1, wherein: the loading of the filter cake was 66% of the ball milling pot volume.

6. The polyphenylene sulfide resin post-treatment purification method according to claim 1, wherein: the drying method is that the drying is carried out for 8-10 hours at the temperature of 80-100 ℃.