Purification method of polyetherketoneketone crude product

Abstract

The invention discloses a purification method of a polyetherketoneketone crude product, and relates to the technical field of engineering resin materials, and the purification method comprises the following steps: quenching the polyetherketoneketone crude product, and pulverizing to obtain polyetherketoneketone crude powder; acid and a solvent are selected and mixed to obtain a mixed solvent; adding the polyetherketoneketone coarse powder into a reactor, adding a mixed solvent, stirring, swelling the polyetherketoneketone coarse powder, and releasing inorganic salt components wrapped in the polyetherketoneketone coarse powder; adding a hydrochloric acid ethanol water solution, refluxing, filtering, washing and decomplexing inorganic salt to obtain a purified polyetherketoneketone sample; and adding an ethanol water solution, washing, filtering and drying to obtain a purified product of polyether ketone ketone. According to the invention, the acid with good solubility to polyether ketone ketone and the solvent have a synergistic effect, so that the swelling effect is obviously improved, and the wrapped aluminum salt is fully released; the aluminum ions are decomplexed step by step through the hydrochloric acid ethanol water solution, and are subjected to multiple times of reflux washing, so that the aluminum residual quantity is reduced to 30 ppm or below, and the purification efficiency is improved by 90% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering resin materials, and particularly relates to a method for purifying crude polyether ketone ketone. Background Art

[0002] Polyether ketone ketone (PEKK) is a high polymer composed of repeating units containing two ketone bonds and one ether bond in the main chain structure. It is a special engineering plastic with excellent properties. Its glass transition temperature is above 150°C, and its melting point is between 330 and 360°C. It has high strength, low density, good biocompatibility, high corrosion resistance, radiation resistance, fatigue resistance, and good wear resistance. It can replace polyimide resin and some metal materials to a certain extent and be used as high-temperature structural materials, electrical insulation materials, biomedical materials, 3D materials, etc. in technical fields such as aerospace, medical devices, electronics and electricity, automobiles, construction, and chemical engineering.

[0003] In the production process of polyether ketone ketone, the electrophilic substitution synthesis method is generally adopted: using diphenyl ether, terephthaloyl chloride, and isophthaloyl chloride as polymerization monomers, aluminum trichloride and N,N-dimethylformamide as catalysts, and dichloromethane / dichloroethane as solvents, and obtaining it through the Friedel-Crafts acylation reaction. A large amount of aluminum chloride catalyst is required in the polymerization reaction process. Aluminum chloride will complex with the ketone groups in the polyether ketone ketone product during the reaction process and after the reaction. Moreover, in the production process of polyether ketone ketone, large lumps of jelly-like substances are often formed, wrapping the aluminum chloride. It is often difficult to remove aluminum during the post-treatment process. In addition, the residual aluminum ions will cause the viscosity of polyether ketone ketone to decrease, the molecular weight to decrease, and the product structure to change, resulting in side reactions and color changes of the product during the subsequent processing. How to effectively remove metal ions in polyether ketone ketone is a key link in synthesizing high-performance polyether ketone ketone. Summary of the Invention

[0004] Technical problem to be solved: Aiming at the problems existing in the synthesis process of polyether ketone ketone in the background art, the present invention provides a method for purifying crude polyether ketone ketone. After quenching and crushing the crude polyether ketone ketone, a mixed solvent composed of a specific acid and a solvent is selected to dissolve the polyether ketone ketone to cause swelling, release the aluminum salt wrapped in the crude polyether ketone ketone powder, and then obtain a purified polyether ketone ketone product through steps such as washing and drying.

[0005] Technical solution: A method for purifying crude polyether ketone ketone according to the present invention, the purification method includes the following steps: Step 1: Quench and crush the crude polyether ketone ketone to obtain crude polyether ketone ketone powder; Step 2: Select an acid that has good solubility in polyether ketone ketone and mix it evenly with a solvent in a volume ratio of 1:(1 - 20) to obtain a mixed solvent; wherein, the acid is one or more of trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropanoic acid, dichloroacetic acid, and dichloropropanoic acid; Step 3: Add the prepared polyether ketone ketone crude powder into a reactor, add the mixed solvent to the reactor in a mass ratio of 1:(2 - 20), and after stirring treatment, swell the polyether ketone ketone crude powder to release the inorganic salt components wrapped therein; Step 4: Add hydrochloric acid ethanol aqueous solution to the reactor in a mass ratio of polyether ketone ketone crude powder to hydrochloric acid ethanol aqueous solution of 1:(3 - 10), and after refluxing and filtering, wash the inorganic salts in the decomplexed polyether ketone ketone crude powder to obtain a purified polyether ketone ketone sample; Step 5: Stir and mix the polyether ketone ketone sample with an ethanol aqueous solution in a mass ratio of 1:(3 - 10), and after washing, filtering, and drying, obtain a purified polyether ketone ketone product.

[0006] Preferably, the solvent in Step 2 is one or more of dichloromethane, dichloroethane, o-dichlorobenzene, and tetrachloroethane.

[0007] Preferably, the hydrochloric acid content in the hydrochloric acid ethanol aqueous solution in Step 4 accounts for 2 - 10% of the mass of the ethanol aqueous solution, and the mass ratio of ethanol to water in the ethanol aqueous solution is 1:(0.05 - 3).

[0008] Preferably, the reflux temperature in Step 4 is 80 - 120 °C, the reflux time is 2 - 8 h, and the number of refluxes is 2 - 5 times.

[0009] Preferably, the mass ratio of ethanol to water in the ethanol aqueous solution in Step 5 is 1:(0.05 - 3), and the number of washing times is 2 times.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. The method of the present invention adopts process steps such as acid swelling → decomplexation → washing → drying, etc. After quenching and crushing the polyether ketone ketone crude product, a mixed solvent composed of a specific acid and a solvent is selected to dissolve the polyether ketone ketone to cause swelling, release the impurities wrapped in the polyether ketone ketone crude powder, and then obtain a purified polyether ketone ketone product through steps such as cleaning and drying; 2. The present invention uses a mixed solvent composed of an acid with strong solubility in PEKK (such as trifluoroacetic acid, dichloroacetic acid, etc.) and a solvent (dichloromethane, dichloroethane, o-dichlorobenzene, etc.) to dissolve and swell the PEKK coarse powder. By combining with an aqueous hydrochloric acid-ethanol solution to decomplex impurities such as aluminum salts in the PEKK coarse powder, the synergistic effect of a specific acid and a specific solvent is adopted to significantly improve the swelling effect and fully release the encapsulated aluminum salts. By stepwise decomplexing aluminum ions with an aqueous hydrochloric acid-ethanol solution and combining with multiple reflux washings, the aluminum residue is reduced to less than 30 ppm, and the efficiency is increased by more than 90% compared with the traditional method. 3. The method of the present invention can be directly applied to the industrial production of PEKK without complex equipment, and by reducing the aluminum residue, the viscosity, molecular weight stability and processing performance of PEKK are significantly improved, meeting the actual production requirements.

[0011] Other beneficial effects of the present invention are stated in the embodiment part of the specification and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a purification flow chart of the PEKK crude product of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the protection scope of the present invention. Figure 1 As shown, the present invention discloses a method for purifying a PEKK crude product, including the following steps:

[0014] As Figure 1 shown, the present invention discloses a method for purifying a PEKK crude product, including the following steps: (I) Quench and crush the PEKK crude product to obtain a PEKK coarse powder; (II) Select an acid with good solubility in PEKK and a solvent and mix them evenly according to a volume ratio of 1:(1~20) to obtain a mixed solvent; wherein, the acid is one or more of trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropanoic acid, dichloroacetic acid, dichloropropanoic acid; the solvent is one or more of dichloromethane, dichloroethane, o-dichlorobenzene, tetrachloroethane; (III) Add the prepared PEKK coarse powder into a reactor, add the mixed solvent to the reactor according to a mass ratio of 1:(2~20), and after stirring, swell the PEKK coarse powder to release the inorganic salt components encapsulated therein; (4) Add hydrochloric acid ethanol aqueous solution to the reactor according to the mass ratio of polyether ketone ketone coarse powder to hydrochloric acid ethanol aqueous solution of 1:(3 - 10), and wash the inorganic salts in the depolymerized polyether ketone ketone coarse powder through reflux and filtration to obtain a purified polyether ketone ketone sample; wherein, the hydrochloric acid content of the hydrochloric acid ethanol aqueous solution accounts for 2 - 10% of the mass of the ethanol aqueous solution, and the mass ratio of ethanol to water in the ethanol aqueous solution is 1:(0.05 - 3); wherein, the reflux temperature is 80 - 120°C, the reflux time is 2 - 8 h, and the number of refluxes is 2 - 5 times; (5) Stir and mix the polyether ketone ketone sample and the ethanol aqueous solution according to the mass ratio of 1:(3 - 10), and obtain a purified polyether ketone ketone product after washing, filtering, and drying; wherein, the mass ratio of ethanol to water in the ethanol aqueous solution is 1:(0.05 - 3), and the number of washing times is 2 times.

[0015] The following are specific embodiments of the present invention to further illustrate the technical solutions and effects of the present invention.

[0016] Example 1: This example discloses a method for purifying polyether ketone ketone crude product. The preparation method is as follows: In a dry 2L reaction kettle, add 50g of polyether ketone ketone coarse powder, and then add a mixed solvent of 100g of dichloroacetic acid and 500g of dichloroethane, and stir and mix evenly for 2h; then add 500g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%), and reflux at a reflux temperature of 100°C for 3h; after filtration, add 500g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%) again, and perform secondary reflux at a reflux temperature of 100°C for 3h; after filtration, add 500g of ethanol aqueous solution (ethanol mass fraction is 60%), stir and wash for 2h, and then repeat the washing once. After filtration, dry at 130°C for 24h to obtain a purified product PEKK - 1.

[0017] Example 2: This example discloses a method for purifying polyether ketone ketone crude product. The preparation method is as follows: In a dry 2L reaction kettle, add 50g of polyether ketone ketone coarse powder, and then add a mixed solvent of 50g of dichloroacetic acid and 500g of dichloromethane, and stir and mix evenly for 2h; then add 500g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 5%, ethanol mass fraction is 95%), and reflux at a reflux temperature of 80°C for 8h; after filtration, add 500g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 5%, ethanol mass fraction is 95%) again, and perform secondary reflux at a reflux temperature of 80°C for 8h; after filtration, add 500g of ethanol aqueous solution (ethanol mass fraction is 95%), stir and wash for 2h, and then repeat the washing once. After filtration, dry at 130°C for 24h to obtain a purified product PEKK - 2.

[0018] Example 3: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, add 45g of crude polyether ketone ketone powder, and then add a mixed solvent of 100g of 3,3,3-trifluoro-2,2-dimethylpropionic acid and 800g of o-dichlorobenzene, and stir and mix evenly for 2h; then add 300g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 10%, ethanol mass fraction is 80%), and reflux at a reflux temperature of 120°C for 2h; after filtration, add 300g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 10%, ethanol mass fraction is 80%) again, and perform secondary reflux treatment at a reflux temperature of 120°C for 2h; after filtration, add 300g of ethanol aqueous solution (ethanol mass fraction is 80%), stir and wash for 2h, and then repeat the washing once. After filtration, dry at 130°C for 24h to obtain the purified product PEKK-3.

[0019] Example 4: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, add 300g of crude polyether ketone ketone powder, and then add a mixed solvent of 300g of dichloroacetic acid and 300g of tetrachloroethane, and stir and mix evenly for 2h; then add 900g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 7%, ethanol mass fraction is 50%), and reflux at a reflux temperature of 120°C for 3h; after filtration, add 900g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 7%, ethanol mass fraction is 50%) again, and perform secondary reflux treatment at a reflux temperature of 120°C for 3h; after filtration, add 900g of ethanol aqueous solution (ethanol mass fraction is 50%), stir and wash for 2h, and then repeat the washing once. After filtration, dry at 130°C for 24h to obtain the purified product PEKK-4.

[0020] Example 5: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, add 100g of crude polyether ketone ketone powder, and then add a mixed solvent of 100g of 3,3,3-trifluoro-2,2-dimethylpropionic acid and 500g of dichloroethane, and stir and mix evenly for 2h; then add 800g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%), and reflux at a reflux temperature of 110°C for 4h; after filtration, add 800g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%) again, and perform secondary reflux treatment at a reflux temperature of 110°C for 4h; after filtration, add 800g of ethanol aqueous solution (ethanol mass fraction is 60%), stir and wash for 2h, and then repeat the washing once. After filtration, dry at 130°C for 24h to obtain the purified product PEKK-6.

[0021] Example 6: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, 80g of crude polyether ketone ketone powder is added, and then a mixed solvent of 50g of dichloropropionic acid and 1000g of dichloromethane is added, and stirred and mixed evenly for 2h; then 500g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 7.5%, ethanol mass fraction is 25%) is added, and reflux treatment is carried out at a reflux temperature of 90°C for 5h; after filtration, 1000g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%) is added again, and secondary reflux treatment is carried out at a reflux temperature of 100°C for 3h; after filtration, 500g of ethanol aqueous solution (ethanol mass fraction is 60%) is added, and stirred and washed for 2h, and then washed once again. After filtration, it is dried at 130°C for 24h to obtain the purified product PEKK-6.

[0022] Example 7: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, 100g of crude polyether ketone ketone powder is added, and then a mixed solvent of 100g of trifluoroacetic acid and 500g of dichloroethane is added, and stirred and mixed evenly for 2h; then 700g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 50%) is added, and reflux treatment is carried out at a reflux temperature of 100°C for 3h; after filtration, 700g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 50%) is added again, and reflux treatment is carried out at a reflux temperature of 100°C for 3h, and the filtration is repeated 4 times; after filtration, 700g of ethanol aqueous solution (ethanol mass fraction is 50%) is added, and stirred and washed for 2h, and then washed once again. After filtration, it is dried at 130°C for 24h to obtain the purified product PEKK-7.

[0023] Example 8: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, 50g of crude polyether ketone ketone powder is added, and then a mixed solvent of 150g of dichloroacetic acid and 450g of o-dichlorobenzene is added, and stirred and mixed evenly for 2h; then 300g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 7.2%, ethanol mass fraction is 60%) is added, and reflux treatment is carried out at a reflux temperature of 110°C for 4h; after filtration, 300g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 7.2%, ethanol mass fraction is 60%) is added again, and reflux treatment is carried out at a reflux temperature of 110°C for 3h, and the filtration is repeated 2 times; after filtration, 300g of ethanol aqueous solution (ethanol mass fraction is 60%) is added, and stirred and washed for 2h, and then washed once again. After filtration, it is dried at 130°C for 24h to obtain the purified product PEKK-8.

[0024] Example 9: This example discloses a method for purifying crude polyether ketone ketone. The preparation method is as follows: In a dry 2L reaction kettle, 60g of crude polyether ketone ketone powder is added, and then 100g of a mixed solvent of trifluoroacetic acid and 500g of dichloroethane is added, and stirred and mixed evenly for 2h; then 600g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 4.5%, ethanol mass fraction is 75%) is added, and reflux treatment is carried out at a reflux temperature of 120°C for 6h; after filtration, 600g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 4.5%, ethanol mass fraction is 75%) is added again, and reflux treatment is carried out at a reflux temperature of 120°C for 6h, and the filtration is repeated 2 times after filtration; after filtration, 600g of ethanol aqueous solution (ethanol mass fraction is 75%) is added, and stirred and washed for 2h, and then washed once again, and dried at 130°C for 24h after filtration to obtain the purified product PEKK-9.

[0025] Comparative Example 1: In a dry 2L reaction kettle, 60g of crude polyether ketone ketone powder is added, and 1000g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%) is added, and reflux treatment is carried out at a reflux temperature of 100°C for 3h; after filtration, 1000g of hydrochloric acid ethanol aqueous solution (hydrochloric acid content is 3.6%, ethanol mass fraction is 60%) is added again, and reflux treatment is carried out at a reflux temperature of 100°C for 3h; after filtration, 500g of ethanol aqueous solution (ethanol mass fraction is 60%) is added, and stirred and washed for 2h, and then washed once again, and dried at 130°C for 24h after filtration to obtain the purified product PEKK-Comparative Example 1.

[0026] The aluminum content of the PEKK samples of Examples 1 to 9 and Comparative Example 1 of the present invention was tested, and the results are shown in Table 1.

[0027] Table 1 Aluminum content results of PEKK samples of Examples 1 to 9 and Comparative Example 1 of the present invention: 。

[0028] As can be seen from Table 1, by comparing the aluminum ion contents of the PEKK samples purified in Examples 1 to 9 of the present invention with the PEKK-Comparative Example 1 sample, it can be known that a mixed solvent composed of an acid with strong solubility in PEKK (such as trifluoroacetic acid, dichloroacetic acid, etc.) and a solvent (dichloromethane, dichloroethane, o-dichlorobenzene, etc.) is used to dissolve and swell the polyether ketone ketone (PEKK) coarse powder. Combining with hydrochloric acid ethanol aqueous solution to decomplex impurities such as aluminum salts in the polyether ketone ketone (PEKK) coarse powder, the synergistic effect of a specific acid and a specific solvent is adopted to significantly improve the swelling effect, so that the encapsulated aluminum salts are fully released; by stepwise decomplexing aluminum ions with hydrochloric acid ethanol aqueous solution and combining with multiple reflux washings, the aluminum residue is reduced to less than 30 ppm; when strong acid swelling is not used, the residual amount of aluminum element in PEKK-Comparative 1 is as high as 335 ppm. The method of the present invention can improve the aluminum ion removal efficiency by more than 90%, effectively remove the residual aluminum ions in the PEKK crude product, and improve the quality of the PEKK product.

[0029] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for purifying a crude polyetherketoneketone, characterized in that: The purification method comprises the following steps: Step 1: Quenching and crushing the crude polyetherketoneketone product to obtain a coarse polyetherketoneketone powder; Step 2: Select an acid with good solubility for polyetherketoneketone and mix it evenly with a solvent in a volume ratio of 1:(1-20) to obtain a mixed solvent; wherein the acid is one or more of trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropionic acid, dichloroacetic acid, and dichloropropionic acid; Step 3: adding the prepared polyetherketoneketone coarse powder into a reactor, adding a mixed solvent into the reactor at a mass ratio of 1:(2-20), and after stirring, swelling the polyetherketoneketone coarse powder to release the inorganic salt component wrapped therein; Step 4: adding hydrochloric acid ethanol aqueous solution to the reactor in a mass ratio of 1: (3-10) between the polyetherketoneketone crude powder and the hydrochloric acid ethanol aqueous solution, and washing out the inorganic salt in the decomplexed polyetherketoneketone crude powder through reflux and filtration to obtain a purified polyetherketoneketone sample; Step 5: Mix the polyetherketoneketone sample and the ethanol aqueous solution in a mass ratio of 1:(3-10), and obtain the polyetherketoneketoneketone purified product after washing, filtering and drying.

2. The method for purifying a crude polyetherketoneketone according to claim 1, characterized in that: In step 2, the solvent is one or more of dichloromethane, dichloroethane, o-dichlorobenzene and tetrachloroethane.

3. The method for purifying a crude polyetherketoneketone according to claim 1, characterized in that: The hydrochloric acid content of the hydrochloric acid ethanol aqueous solution in step 4 accounts for 2-10% of the mass of the ethanol aqueous solution, and the mass ratio of ethanol to water in the ethanol aqueous solution is 1:(0.05-3).

4. The method for purifying a crude polyetherketoneketone according to claim 1, characterized in that: In step 4, the reflux temperature is 80-120° C., the reflux time is 2-8 h, and the reflux times are 2-5 times.

5. The method for purifying a crude polyetherketoneketone according to claim 1, characterized in that: In step 5, the mass ratio of ethanol to water in the ethanol aqueous solution is 1:(0.05-3), and the number of washing times is 2 times.

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