Sulfone polymer powder with high bulk density and narrow molecular weight distribution and preparation method thereof

Abstract

The invention discloses sulfone polymer powder with high bulk density and narrow molecular weight distribution and a preparation method thereof. The weight-average molecular weight Mw range of a sulfone polymer is 2 * 10 < 4 >-20 * 10 < 4 >, the molecular weight distribution is less than 3, the content of oligomer (Mw is less than 5000) is less than 5wt%, the bulk density of the sulfone polymer powder is greater than 0.2 g / mL, and the content of particle black spots is less than 100 / 500g. According to the sulfone polymer powder, an organic bisphenol compound, 4, 4 '-dichloro diphenyl sulfone and a salt-forming agent are adopted as raw materials and subjected to a polymerization reaction in an aprotic polar solvent, a dispersing agent is added into a polymer solution, then powder is separated out in a mixed solution, the polymer powder is subjected to microwave washing through the mixed solution, the stacking density is increased, and the polymer powder is obtained. The low polymer content is reduced, the molecular weight distribution is narrowed, the heat resistance is improved, and the appearance performance of the material is greatly improved after extrusion granulation.

Description

Technical Field

[0001] The present invention relates to a sulfone polymer with high bulk density and narrow molecular weight distribution and a preparation method thereof, belonging to the field of polymer materials. Background Art

[0002] Sulfone polymers are important thermoplastic special engineering plastics, mainly including polyethersulfone (PES), bisphenol A polysulfone (PSU), polyphenylene sulfone (PPSU), etc. Sulfone polymer resins have excellent properties, such as excellent mechanical properties, high temperature resistance, chemical corrosion resistance, aging resistance, etc. These characteristics enable such materials to be widely used in many fields such as aerospace, national defense, electronics and electrical, medical, nuclear power, oil wells, ships, magnet wires, military industry, automobile manufacturing industry, and food processing.

[0003] The reaction mechanism of sulfone polymers is nucleophilic polycondensation. The monomer reaction activity is not high, the reaction rate is low, the oligomer content in the final product is high, and the molecular weight distribution is often very wide. This leads to poor thermal stability during the subsequent hot processing of the material, degradation and yellowing, and the generation of black spots, restricting the application of the material in high-end fields, especially in the field of transparent products. A large number of benzene rings and ether bonds are contained in the main chain of sulfone polymers, which is a strong and tough material. Generally, solution polymerization is used. After the polymerization is completed, the polymer solution is poured into water for precipitation and pulverization. The polymer immediately precipitates and solidifies into a porous structure when it comes into contact with water. The strong and tough characteristics make this porous solid can only be pulverized into fluffy flocculent powder, with a very low bulk density. During the extrusion granulation process, the feeding amount is extremely low, the screw is in a starving state, and the material is prone to oxidation and discoloration, generating a large number of black spots.

[0004] Therefore, it is necessary to develop a sulfone polymer with a narrow molecular weight distribution, a large powder bulk density, and even a small content of particle black spots. Summary of the Invention

[0005] The present invention discloses a sulfone polymer powder with high bulk density and narrow molecular weight distribution and a preparation method thereof. The present invention uses organic bisphenol compounds, 4,4'-dichlorodiphenyl sulfone, and a salt-forming agent as raw materials, conducts a polymerization reaction in an aprotic polar solvent, adds a dispersant to the polymer solution, and then precipitates into powder in the mixed solution. The polymer powder is then washed by microwave in the mixed solution, resulting in an increased bulk density, a reduced oligomer content, a narrowed molecular weight distribution, an improved heat resistance, and greatly improved appearance properties of the material after extrusion granulation.

[0006] To achieve the above invention purposes, the technical solutions adopted by the present invention are as follows:

[0007] A sulfone polymer powder with high bulk density and narrow molecular weight distribution has the following characteristics:

[0008] 1) The weight-average molecular weight Mw ranges from 2×10 4 to 20×10 4 , such as 3×10 4 , 4×10 4 , 5×10 4 , 6×10 4 , 7×10 4 , 8×10 4 , 9×10 4 , 10×10 4 , 11×10 4 , 12×10 4 , 13×10 4 , 14×10 4 , 15×10 4 , 16×10 4 , 17×10 4 , 18×10 4 , 19×10 4 , 20×10 4 etc.;

[0009] 2) The molecular weight distribution is < 3, such as 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, etc., preferably ≤ 2;

[0010] 3) The content of oligomers (Mw < 5000) is < 5%, such as 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, etc., preferably < 4%;

[0011] 4) The powder bulk density > 0.2 g / mL, such as 0.25 g / mL, 0.3 g / mL, 0.35 g / mL, 0.4 g / mL, 0.45 g / mL, 0.5 g / mL, 0.55 g / mL, 0.6 g / mL, 0.65 g / mL, 0.7, etc., preferably ≥ 0.3 g / mL;

[0012] 5) The content of particle black dots is < 100 pieces / 500 g, such as 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 piece, etc., preferably < 50 pieces / 500 g, more preferably < 30 pieces / 500 g.

[0013] Those skilled in the art can understand that the sulfone polymer powder products that meet the above technical features can meet the application requirements in the field of high-end transparent products, regardless of the preparation method used. To exemplify the existence of the sulfone polymer powder products with the above technical features, the present invention exemplarily provides a specific preparation method, but it does not mean that the products meeting the corresponding technical features must be obtained by using the preparation method of the present invention, and the preparation methods described below in the present invention do not constitute any limitation either.

[0014] Specifically, the preparation method of the above-mentioned sulfone polymer powder with high bulk density and narrow molecular weight distribution includes the following steps:

[0015] 1) An organic bisphenol compound, 4,4'-dichlorodiphenyl sulfone, and a salt-forming agent are subjected to a polymerization reaction in an aprotic polar solvent to obtain a polymer solution;

[0016] 2) A dispersant is added to the polymer solution obtained in step 1), and after stirring evenly, it is put into a mixed solution as a precipitation solution for precipitation and pulverization to obtain a polymer powder;

[0017] 3) The polymer powder obtained in step 2) is washed multiple times with a mixed solvent as a washing solution under microwave assistance and then dried to obtain a pure sulfone polymer powder.

[0018] In a specific embodiment, the organic bisphenol compound described in step 1) is selected from one or more of bisphenol A, bisphenol S, bisphenol F, hydroquinone, resorcinol, dihydroxybenzophenone, dihydroxydiphenyl ether, 4,4'-biphenol, hexafluorobisphenol A, tetrabromobisphenol A, and dihydroxynaphthalene; and / or

[0019] The salt-forming agent is selected from one or more of potassium carbonate, sodium carbonate, sodium hydroxide, and potassium hydroxide; and / or

[0020] The aprotic polar solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, sulfolane, diphenyl sulfone, dimethyl sulfone, and biphenylphenylsulfinyl.

[0021] In step 1), the molar ratio of the organic bisphenol compound to 4,4'-dichlorodiphenyl sulfone is 1:0.95 to 1:1.05, such as 1:0.95, 1:0.99, 1:1, 1:1.02, 1:1.05, etc., and preferably 1:0.97 to 1:1.03;

[0022] In step 1), the molar ratio of the organic bisphenol compound to the salifying agent is 1:1 to 1:2, such as 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, etc., and preferably 1:1.1 to 1:1.7.

[0023] In step 1), the solid content of the system is 10 wt% to 50 wt%, such as 10%, 20%, 30%, 40%, 50%, etc., and preferably 20% to 40%; wherein, the solid content of the system refers to the mass of the polymer in the reaction system / the total mass of the polymer plus the solvent, that is, the mass of the polymer in the polymer solution obtained in step 1 / the total mass of the polymer solution.

[0024] The reaction temperature in step 1) is 150 to 220 °C, such as 150 °C, 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, etc., and the reaction time is 5 to 20 h, such as 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, etc.

[0025] In a specific embodiment, the dispersant in step 2) is selected from one or more of polyethylene glycol, sodium polyacrylate, and polyvinyl alcohol;

[0026] Preferably, the addition amount of the dispersant is 0.1% to 1% of the mass of the polymer solution, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.

[0027] In step 2), the weight ratio of the polymer solution to the mixed solvent as the precipitation liquid is 1:5 to 1:15, such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, etc. Among them, the mixed solvent as the precipitation liquid is a mixture of a good solvent and a poor solvent for the polymer, and the weight ratio of the two is 0:1 to 1:1, such as 0:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, etc.; among them, the good solvent for the polymer is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, sulfolane, diphenyl sulfone, dimethyl sulfone, and biphenyl phenylsulfinyl; among them, the poor solvent for the polymer is selected from one or more of water, ethanol, methanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, and acetonitrile.

[0028] In a specific embodiment, the weight ratio of the polymer powder to the mixed solvent as the washing liquid in step 3) is 1:5 to 1:15, such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, etc.

[0029] In the present invention, the mixed solvent as the washing liquid is a mixture of a good solvent and a poor solvent for the polymer, and the weight ratio of the two is 1:1 to 4:1, such as 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, etc.; wherein, the polymer good solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, sulfolane, diphenyl sulfone, dimethyl sulfone, biphenyl benzene sulfoxide; the polymer poor solvent is selected from one or more of water, ethanol, methanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, acetonitrile.

[0030] In the present invention, the washing operation is carried out under microwave assistance, and the frequency of the microwave is not particularly limited, such as 40 - 100 KHz, etc.

[0031] In the present invention, the washing temperature is 80 - 120 °C, such as 80 °C, 90 °C, 100 °C, 10 °C, 120 °C, etc., the single washing time is 1 - 5 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, etc., and the washing times are 1 - 5 times, such as 1 time, 2 times, 3 times, 4 times, 5 times, etc.

[0032] Compared with the prior art, the positive effects of the present invention are as follows:

[0033] The present invention is designed from the perspective of polymer phase change. A dispersant is added to the polymer solution, and it is pulverized and precipitated in a poor solvent containing a good solvent. One end of the dispersant can bind to the polymer, and the other end binds to the poor solvent. By controlling the proportion of the good solvent, the polymer aggregate structure can be regulated, the polymer precipitation rate can be delayed, and a more regular powder with a higher packing density can be formed; then the powder is microwave-washed with a poor solvent containing a good solvent, which can remove the oligomer components in the polymer, narrow the molecular weight distribution, further improve the powder packing density. After granulation, the optical properties and heat resistance of the product are improved, and the content of black dots in the particles is reduced, which has practical application value. Specific Embodiments

[0034] In order to better understand the technical solution of the present invention, the method provided by the present invention will be further described below. However, the present invention is not limited to the listed embodiments, and should also include any other known changes within the scope of the claims of the present invention.

[0035] Example 1:

[0036] A four-necked flask equipped with a water separator, a condenser and a mechanical stirrer was placed in an oil bath reactor. 0.25 mol of bisphenol A, 0.375 mol of potassium carbonate, 0.238 mol of 4,4'-dichlorodiphenyl sulfone, and 947.7 g of N,N-dimethylacetamide were added to the flask in sequence. The reaction temperature was raised to 165°C and the reaction was carried out for 10 hours to obtain a viscous polysulfone solution. 1.06 g of polyethylene glycol was added to the polymer solution and stirred until uniform.

[0037] The polymer solution was put into 5.265 kg N, N-dimethylacetamide / ethanol mixed solution (weight ratio 1:1) to precipitate into powder. The powder was added into 526.5 g N, N-dimethylacetamide / ethanol mixed solution (weight ratio 1:1), stirred and washed in a microwave cleaning apparatus (40 KHz), the washing temperature was 100 ° C, the washing was performed for 3 hours, and the washing was repeated 3 times, and then washed once with ethanol, and dried to obtain a polymer powder.

[0038] Embodiment 2:

[0039] In a four-necked reaction flask equipped with oil bath heating, a stirrer, a water separator and a condenser, 0.1 mol of bisphenol S, 0.1 mol of sodium carbonate, 0.098 mol of 4,4'-dichlorodiphenyl sulfone and 45.5 g of N,N-dimethylformamide were added in sequence. The reaction temperature was raised to 150°C and the reaction was carried out for 20 hours to obtain a viscous polysulfone solution. 0.91 g of polyethylene glycol was added to the polymer solution and stirred until uniform.

[0040] The polymer solution was put into 910g of N,N-dimethylformamide / water mixture (weight ratio 0:1) to precipitate into powder. The powder was added into 455g of N,N-dimethylformamide / water mixture (weight ratio 4:1), stirred and washed in a microwave cleaning apparatus (100KHz), the washing temperature was 80°C, the washing was performed for 5 hours, the washing was repeated 5 times, and then washed once with pure water, and dried to obtain polymer powder.

[0041] Embodiment 3:

[0042] 1 mol of bisphenol A, 2 mol of potassium carbonate, 1.05 mol of 4,4'-dichlorodiphenyl sulfone and 1.032 kg of cyclopentane sulfone were put into a reactor equipped with temperature control, stirring and reflux water separation devices at one time. The reaction temperature was raised to 220°C and the reaction was carried out for 5 hours to obtain a viscous polysulfone solution. 7.36 g of polyvinyl alcohol was added to the polymer solution and stirred until uniform.

[0043] The polymer solution was poured into 22.12 kg of a sulfolane / ethyl acetate mixture (weight ratio 0.5:1), and precipitated into a powder. The powder was added to 6.64 kg of a sulfolane / ethyl acetate mixture (weight ratio 2:1), and stirred and washed in a microwave cleaner (40 KHz). The washing temperature was 120 °C, and the washing was carried out for 1 h. After washing once, it was washed once more with ethyl acetate, and then dried to obtain the polymer powder.

[0044] Example 4:

[0045] 4 mol of 4,4′-biphenol, 6 mol of potassium carbonate, 4 mol of 4,4'-dichlorodiphenyl sulfone, and 6.41 kg of N-methylpyrrolidone were charged into a reaction kettle equipped with a temperature control, stirring, and reflux water separation device at one time. The reaction temperature was raised to 190 °C, and the reaction was carried out for 12 h to obtain a viscous polysulfone solution. 80 g of polyethylene glycol was added to the polymer solution and stirred until homogeneous.

[0046] The polymer solution was poured into 80 kg of an N-methylpyrrolidone / ethanol mixture (weight ratio 1:1), and precipitated into a powder. The powder was added to 16 kg of an N-methylpyrrolidone / ethanol mixture (weight ratio 1:1), and stirred and washed in a microwave cleaner (40 KHz). The washing temperature was 100 °C, and the washing was carried out for 2 h. After washing twice, it was washed once more with ethanol, and then dried to obtain the polymer powder.

[0047] Comparative Example 1:

[0048] A four-necked flask equipped with a water separator, a condenser, and mechanical stirring was placed in an oil bath reactor. 0.25 mol of bisphenol A, 0.375 mol of potassium carbonate, 0.238 mol of 4,4'-dichlorodiphenyl sulfone, and 947.7 g of N,N-dimethylacetamide were successively added to the flask. The oil bath temperature was directly raised to 165 °C, and the reaction was carried out for 10 h to obtain a yellow viscous polysulfone solution.

[0049] The polymer solution was poured into 5.265 kg of water, and precipitated into a powder. The powder was added to 526.5 g of water for stirring and washing. The washing temperature was 100 °C, and the washing was carried out for 3 h. After washing four times, it was dried to obtain the polymer powder.

[0050] Comparative Example 2:

[0051] A four-necked flask equipped with a water separator, a condenser, and mechanical stirring was placed in an oil bath reactor. 0.25 mol of bisphenol A, 0.375 mol of potassium carbonate, 0.238 mol of 4,4'-dichlorodiphenyl sulfone, and 947.7 g of N,N-dimethylacetamide were successively added to the flask. The oil bath temperature was directly raised to 165 °C, and the reaction was carried out for 10 h to obtain a yellow viscous polysulfone solution.

[0052] The polymer solution was poured into 10.53 kg of water and precipitated into powder. The powder was added to 1.053 kg of water for stirring and washing. The washing temperature was 100 °C, and the washing was carried out for 3 h. After washing 10 times, it was dried to obtain polymer powder.

[0053] The performance indexes of the sulfone polymers obtained in the examples and comparative examples were detected. The test methods are as follows:

[0054] 1) Weight-average molecular weight Mw, distribution, and oligomer content: Tested by gel permeation chromatography (GPC), using DMF as the mobile phase and PMMA as the standard sample;

[0055] 2) Bulk density: Bulk density tester, GB / T 16913.3-2008;

[0056] 3) Black dot content: OCS laser tester.

[0057] The test results are shown in the following table:

[0058]

[0059] It can be seen from the examples and comparative examples that the sulfone polymer prepared by the method of the present invention has a narrow molecular weight distribution, significantly reduced oligomer content, increased bulk density, greatly reduced black dot content after extrusion, and greatly improved appearance performance.

Claims

1. A sulfone polymer powder with high bulk density and narrow molecular weight distribution, characterized in that, it has the following characteristics: 1) The weight-average molecular weight Mw ranges from 2×10 4 to 20×10 4 ; 2) Molecular weight distribution < 3; 3) Content of oligomers (Mw < 5000) < 5%; 4) Powder bulk density > 0.2 g / mL; 5) Content of particle black dots < 100 per 500 g.

2. A method for preparing the sulfone polymer powder with high bulk density and narrow molecular weight distribution according to claim 1, characterized in that, it includes the following steps: 1) An organic bisphenol compound, 4,4'-dichlorodiphenyl sulfone, and a salt-forming agent are subjected to a polymerization reaction in an aprotic polar solvent to obtain a polymer solution; 2) A dispersant is added to the polymer solution obtained in step 1), and after stirring evenly, it is put into a mixed solvent as a precipitation solution for precipitation and pulverization to obtain a polymer powder; 3) The polymer powder obtained in step 2) is washed multiple times with a mixed solvent as a washing solution under microwave assistance and then dried to obtain a pure sulfone polymer powder.

3. According to the preparation method described in claim 2, characterized in that, the organic bisphenol compound described in step 1) is selected from one or more of bisphenol A, bisphenol S, bisphenol F, hydroquinone, resorcinol, dihydroxybenzophenone, dihydroxydiphenyl ether, 4,4'-biphenol, hexafluorobisphenol A, tetrabromobisphenol A, dihydroxynaphthalene; and / or the salt-forming agent is selected from one or more of potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide; and / or the aprotic polar solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, sulfolane, diphenyl sulfone, dimethyl sulfone, biphenyl phenylsulfinyl.

4. According to the preparation method described in claim 2 or 3, characterized in that, in step 1), the molar ratio of the organic bisphenol compound to 4,4'-dichlorodiphenyl sulfone is 1:0.95 to 1:1.05, preferably 1:0.97 to 1:1.03; and / or the molar ratio of the organic bisphenol compound to the salt-forming agent is 1:1 to 1:2, preferably 1:1.1 to 1:1.

7.

5. According to the preparation method described in any one of claims 2 to 4, characterized in that, in step 1), the solid content of the system is 10 wt% to 50 wt%, preferably 20 wt% to 40 wt%.

6. According to the preparation method described in any one of claims 2 to 5, characterized in that, the reaction temperature of step 1) is 150 to 220 °C, and the reaction time is 5 to 20 h.

7. According to the preparation method described in claim 2, characterized in that, the dispersant described in step 2) is selected from one or more of polyethylene glycol, sodium polyacrylate, polyvinyl alcohol; preferably, the addition amount of the dispersant is 0.1% to 1% of the mass of the polymer solution.

8. According to the preparation method described in claim 2 or 7, characterized in that, in step 2), the weight ratio of the polymer solution to the mixed solvent as the precipitation solution is 1:5 to 1:15; Preferably, the mixed solvent as the precipitation solution is a mixture of a good solvent and a poor solvent for the polymer, and the weight ratio of the two is 0:1 to 1:1, preferably 0.3:1 to 0.7:1; More preferably, the polymer good solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, sulfolane, diphenyl sulfone, dimethyl sulfone, biphenyl phenyl sulfoxide; and / or The polymer poor solvent is selected from one or more of water, ethanol, methanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, acetonitrile.

9. The preparation method according to claim 2, characterized in that in step 3), the weight ratio of the polymer powder to the mixed solvent as the washing solution is 1:5 to 1:15; Preferably, the mixed solvent as the washing solution is a mixture of a good solvent and a poor solvent for the polymer, and the weight ratio of the two is 1:1 to 4:1; More preferably, the polymer good solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, sulfolane, diphenyl sulfone, dimethyl sulfone, biphenyl phenyl sulfoxide; and / or The polymer poor solvent is selected from one or more of water, ethanol, methanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, acetonitrile.

10. The preparation method according to claim 2 or 9, characterized in that in step 3), the washing temperature is 80 to 120 °C, the single washing time is 1 to 5 h, and the washing times are 1 to 5 times.

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