Preparation method of polyamide ether imide

Abstract

The invention discloses a preparation method of polyamide ether imide, which comprises the following steps: adding a diamine monomer, trimellitic anhydride acyl chloride and an end-capping reagent into extrusion reaction equipment according to a stoichiometric ratio, reacting at 100-400 DEG C, extruding, and granulating to obtain polyamide ether imide, the molar ratio of the diamine monomer to the trimellitic anhydride acyl chloride is (0.95: 1.05)-(1.05: 0.95); the dosage of the end-capping reagent is 0.1-1 mol% of the diamine monomer. The invention provides a novel melt reaction extrusion process, the diamine monomer, trimellitic anhydride acyl chloride and the end-capping reagent are directly subjected to melt reaction extrusion through extrusion reaction equipment, the polyamide ether imide polymer with high performance characteristic and excellent formability of PAI is prepared, the use of an organic solvent is avoided, and the cost is reduced. The product does not need solvent removal and purification treatment, and the problems of purity defect and performance degradation caused by solvent residue in the traditional process are fundamentally solved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a method for preparing polyamide ether imide. Background Technology

[0002] Polyamide-imide (PAI), a type of polymer whose main chain consists of regularly alternating imide rings and amide bonds, has significant application value in the automotive, electronics, and aerospace industries due to its high glass transition temperature, excellent comprehensive mechanical properties, and wear resistance. However, the inherently high glass transition temperature and high melt strength of PAI significantly limit its melt flowability, severely restricting the precision molding of thin-walled and complex structural parts, and greatly limiting the expansion of its application scenarios.

[0003] Currently, the mainstream industrial synthesis processes for PAI focus on the acyl chloride method and the diisocyanate method. The former involves the reaction of trimellitic anhydride chloride with diamine in a polar solvent, relying on acid-binding agents such as triethylamine to drive the reaction forward; the latter involves the polymerization reaction of trimellitic anhydride and diisocyanate in a polar solvent system. Although both methods can produce high-performance PAI, they share significant drawbacks: the synthesis process is forced to rely on a polar organic solvent system, necessitating complex solvent removal treatments, and solvent residues are difficult to completely eliminate, affecting product purity and long-term stability; the processes are lengthy and require stringent equipment, significantly increasing production costs and energy consumption.

[0004] In addition, some studies have proposed a polycondensation method to prepare the product, attempting to avoid solvent problems by directly reacting trimellitic anhydride with diamine monomers. However, due to low reactivity and harsh conditions, only low molecular weight and low quality products can be obtained, which cannot meet the industrial performance requirements.

[0005] In summary, existing PAI synthesis technologies are still hampered by the trade-off between process complexity, solvent residue risks, and high costs. Furthermore, the inherent processing limitations of the material further hinder its deep application in precision manufacturing. Therefore, there is an urgent need to develop a novel polymer synthesis route that is simple, environmentally friendly, and cost-effective, significantly improving the processability of PAI to meet the demands of precision molding while retaining its high-performance characteristics. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the purpose of this invention is to propose a novel solvent-free melt reactive extrusion process to directly prepare polyamide-etherimide (PAEI) polymers that have both high performance characteristics and excellent formability.

[0007] This invention is achieved through the following technical solution:

[0008] A method for preparing polyamide ether imide includes the following steps:

[0009] Diamine monomer, trimellitic anhydride chloride and end-capping agent are added to an extrusion reaction device in a stoichiometric ratio, and the reaction is carried out at 100-400℃. The mixture is then extruded, granulated and prepared to obtain polyamide ether imide.

[0010] The molar ratio of the diamine monomer to trimellitic anhydride acyl chloride is 0.95:1.05 to 1.05:0.95; the amount of the capping agent is 0.1 to 1 mol% of the diamine monomer, preferably 0.15 to 0.5 mol%.

[0011] Preferably, the diamine monomer is selected from aromatic diether diamines.

[0012] More preferably, the diamine monomer is selected from at least one of the following:

[0013]

[0014] More preferably, the diamine monomer is selected from at least one of the following:

[0015]

[0016]

[0017] Preferably, the capping agent is selected from at least one of amine capping agents, anhydride capping agents, or acyl chloride capping agents.

[0018] The amine end-capping agent includes any one of the following: monofunctional aliphatic amines with 1-10 carbon atoms, aniline, benzidine, diphenyl ether amine, and cyclohexylamine. Further, the monofunctional aliphatic amines with 1-10 carbon atoms include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, tert-butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, and decylamine.

[0019] The anhydride-based capping agent includes any one of phthalic anhydride and naphthalene anhydride.

[0020] The acyl chloride end-capping agent includes benzoyl chloride.

[0021] Preferably, the end-capping agent is mixed with the diamine monomer and then simultaneously fed into the extrusion reaction equipment, or the end-capping agent is mixed with trimellitic anhydride chloride and then simultaneously fed into the extrusion reaction equipment, or the end-capping agent is fed into the reaction system separately at the end of the extrusion reaction equipment in the form of a liquid column or a gas; preferably, the end-capping agent is fed into the reaction system separately at the end of the extrusion reaction equipment in the form of a liquid column or a gas. The polyamide ether imide product prepared by this method has a narrow molecular weight distribution, high molecular weight, and high end-capping efficiency.

[0022] Furthermore, amine end-capping agents can be mixed with diamine monomers in a certain proportion and then simultaneously fed into the reactive extrusion equipment; anhydride end-capping agents and acyl chloride end-capping agents can be mixed with trimellitic anhydride acyl chloride in a certain proportion and then simultaneously fed into the reactive extrusion equipment.

[0023] Preferably, the extrusion reaction equipment includes a feeding section, a mixing section, a polymerization section, a post-polymerization section, and a discharging section; the temperature of the feeding section is controlled at 100℃-200℃, the temperature of the mixing section is controlled at 150℃-250℃, the temperatures of the polymerization and post-polymerization sections are controlled at 200℃-400℃, and the temperature of the discharging section is controlled at 300-360℃. It should be noted that mixing and polymerization are not completely independent; partial polymerization occurs during the mixing and melting process, albeit to a low degree.

[0024] Preferably, the feeding section, mixing section, polymerization section, and post-polymerization section of the extrusion reaction equipment are each equipped with an exhaust port. Further, the exhaust ports of the feeding section and mixing section are atmospheric pressure exhaust ports, and these atmospheric pressure exhaust ports have an anti-overflow function; the exhaust ports of the polymerization section and post-polymerization section are vacuum exhaust ports. Preferably, the pressure of the feeding section and mixing section is controlled at 0 to -0.08 MPa, the pressure of the polymerization section is controlled at -0.06 MPa to -0.9 MPa, and the pressure of the post-polymerization section is controlled at -0.09 MPa to -0.1 MPa.

[0025] Preferably, the material residence time in the extrusion reaction equipment is 3-20 minutes, more preferably 5-15 minutes. The preparation method of this invention significantly shortens the polymerization reaction time. Excessive residence time would increase equipment investment costs but would not significantly affect product performance.

[0026] Preferably, the reactive extrusion equipment of the present invention is selected from any one of a single-screw extruder, a twin-screw extruder, a three-screw extruder, a planetary screw extruder, and a continuous mixer, and more preferably a twin-screw extruder.

[0027] Preferably, the length-to-diameter ratio (L / D) of the cylinder of the extrusion reaction equipment is greater than 40:1.

[0028] The present invention also provides a polyamide ether imide material, which is prepared by the preparation method described in the present invention.

[0029] The present invention has the following beneficial effects:

[0030] This invention proposes a novel melt reactive extrusion process that directly melts and extrudes diamine monomers, trimellitic anhydride acyl chloride, and a capping agent through a reactive extrusion device to prepare a polyamide ether imide polymer that combines the high performance characteristics of PAI with excellent formability. The preparation method is simple and efficient, avoids the use of organic solvents, and produces a high-purity product that eliminates the need for further purification treatments such as solvent removal and small molecule removal. This fundamentally solves the purity defects and performance degradation problems caused by solvent residues in traditional processes, resulting in polyamide ether imide products with stable quality suitable for industrial production.

[0031] The polyamide ether imide material of the present invention has high heat resistance, excellent comprehensive performance and processability, and is suitable for the preparation of thin-walled parts and precision parts in the field of precision manufacturing. Detailed Implementation

[0032] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art with reference to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0033] The reagents used in the embodiments and comparative examples of this invention are all commercially available, but are not limited to these materials.

[0034] Example 1

[0035] Bisphenol S-type diether diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride acyl chloride is 1.03:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of bisphenol S-type diether diphenylamine.

[0036] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The material residence time was 10 minutes.

[0037]

[0038]

[0039] Bisphenol S-type diether diphenylamine was fed into a twin-screw extruder at a rate of 14.82 kg / h. 0.3 wt% benzoyl chloride and trimellitic anhydride acyl chloride were mixed evenly and fed into the twin-screw extruder at a rate of 7.04 kg / h. After mixing, polymerization and post-polymerization, the mixture was drawn from the extruder, cooled by water and air-dried, and then entered a pelletizer for pelletizing. The pellets were then bagged and packaged to prepare polyamide ether imide.

[0040] Example 2

[0041] Bisphenol A type diether diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride acyl chloride is 1.05:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of bisphenol A type diether diphenylamine.

[0042] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The material residence time was 12 minutes.

[0043]

[0044] Bisphenol A type diether diphenylamine was fed into a twin-screw extruder at a rate of 14.35 kg / h. 0.3 wt% benzoyl chloride and trimellitic anhydride acyl chloride were mixed evenly and fed into a twin-screw extruder at a rate of 7.04 kg / h. After mixing, polymerization and post-polymerization, the mixture was drawn from the extruder, water-cooled and air-dried, and then entered a pelletizer for pelletizing. Subsequently, it was bagged and packaged to prepare polyamide ether imide.

[0045] Example 3

[0046] Biphenyl diether diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride chloride is 1.02:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of biphenyl diether diphenylamine.

[0047] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The material residence time was 10 minutes.

[0048]

[0049] Biphenyl diether diphenylamine was fed into a twin-screw extruder at a rate of 12.5 kg / h. 0.3 wt% benzoyl chloride and trimellitic anhydride chloride were mixed evenly and fed into a twin-screw extruder at a rate of 7.04 kg / h. After mixing, polymerization and post-polymerization, the mixture was drawn from the extruder, cooled by water and air-dried, and then entered a pelletizer for pelletizing. The pellets were then bagged and packaged to prepare polyamide ether imide.

[0050] Example 4

[0051] diphenyl ether type diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride chloride is 1.03:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of biphenyl diether diphenylamine.

[0052] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The residence time was 10 minutes.

[0053]

[0054]

[0055] Diphenyl ether type diphenylamine was fed into a twin-screw extruder at a rate of 13.2 kg / h. 0.3 wt% benzoyl chloride and trimellitic anhydride chloride were mixed evenly and fed into a twin-screw extruder at a rate of 7.04 kg / h. After mixing, polymerization and post-polymerization, the mixture was drawn from the extruder, cooled by water and air-dried, and then entered a pelletizer for pelletizing. The pellets were then bagged and packaged to prepare polyamide ether imide.

[0056] Example 5 (amine: anhydride = 1.05:1, 0.5 mol% end-capped)

[0057] Naphthol-type diether diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride acyl chloride is 1.05:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of naphthol-type diether diphenylamine.

[0058] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The residence time was 15 minutes.

[0059]

[0060] Naphthol-type diether diphenylamine was fed into a twin-screw extruder at a rate of 11.97 kg / h. 0.3 wt% benzoyl chloride and trimellitic anhydride chloride were mixed evenly and fed into a twin-screw extruder at a rate of 7.04 kg / h. After mixing, polymerization and post-polymerization, the mixture was drawn from the extruder, cooled by water and air-dried, and then entered a pelletizer for pelletizing. The pellets were then bagged and packaged to prepare polyamide ether imide.

[0061] Example 6: (Amine:Anhydride = 1.02:1, 0.5 mol% end-capped)

[0062] Hydroquinone type diether diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride acyl chloride is 1.05:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of hydroquinone-type diether diphenylamine.

[0063] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The residence time was 15 minutes.

[0064]

[0065] Hydroquinone-type diether diphenylamine was fed into a twin-screw extruder at a rate of 10.22 kg / h. Benzoyl chloride and trimellitic anhydride chloride were mixed evenly and fed into a twin-screw extruder at a rate of 7.04 kg / h. After mixing, polymerization and post-polymerization, the mixture was drawn from the extruder, cooled by water and air-dried, and then entered a pelletizer for pelletizing. The pellets were then bagged and packaged to prepare polyamide ether imide.

[0066] Example 7:

[0067] Bisphenol S-type diether diphenylamine The molar ratio of trimellitic anhydride acyl chloride to methylamine is 1:1.03, and the capping agent methylamine is added to the reaction system by gas injection.

[0068] A twin-screw extruder was used as the reaction equipment. The length-to-diameter ratio of the extruder was 60:1. The reaction was divided into 15 heating zones and 5 exhaust ports. The temperature settings for each zone and the pressure settings for the exhaust ports are shown in the table below. The material residence time was 10 minutes.

[0069]

[0070]

[0071] Bisphenol S-type diether diphenylamine was fed into a twin-screw extruder at a rate of 14.4 kg / h. Tripterygium tricarboxylic acid chloride was fed into the twin-screw extruder simultaneously with bisphenol S-type diether diphenylamine at a rate of 7.25 kg / h. After mixing, polymerization and post-polymerization, methylamine, a capping agent, was injected into the capping agent injection port (the amount of methylamine does not need to be controlled; after entering the screw extruder, methylamine comes into contact with the post-polymerized material, and the unreacted end groups react with methylamine to cap the end groups; the unreacted methylamine is extracted from the vacuum exhaust port 3). The material was then drawn from the extruder, water-cooled, air-dried, and pelletized in a pelletizer, and then bagged and packaged to prepare polyamide ether imide.

[0072] Comparative Example 1

[0073] Bisphenol S-type diether diphenylamine The molar ratio of benzoyl chloride to trimellitic anhydride acyl chloride is 1.03:1, and the amount of benzoyl chloride used as the capping agent is 0.5 mol of bisphenol S-type diether diphenylamine.

[0074] 24.5 kg of N,N-dimethylacetamide (DMAC) was added to a 50 L glass reactor, followed by 5.56 kg of bisphenol S-type diether diphenylamine. Under nitrogen protection, the temperature was maintained at 30-35 °C. 2.63 kg of trimellitic anhydride was added in 10 portions, followed by 8.7 g of benzoyl chloride. 1.26 kg of triethylamine was then added, and the mixture was stirred stably for 6 hours. The temperature was then raised to 75 °C, and stirring continued for another 6 hours. 1.29 kg of acetic anhydride was added, and the reaction was continued for 10 hours. The mixture was then discharged into water to precipitate, pulverized, and subsequently extracted 10 times with pure water under boiling conditions. The final product was then dried.

[0075] Product-related performance testing methods:

[0076] 1. Heat resistance test: The glass transition temperature is tested in accordance with standard ISO 11357.

[0077] 2. Mechanical property testing:

[0078] (1) Tensile strength: Tested according to standard ISO 527;

[0079] (2) Bending strength: Tested according to standard ISO 178;

[0080] (3) Flexural modulus: Tested according to standard ISO 178;

[0081] (4) Notched impact strength: Tested according to standard ISO 180.

[0082] 3. Flowability test: Archimedes spiral test method, injection temperature is 340℃, 335℃, 330℃, 320℃, 315℃; injection pressure is 105MPa, mold thickness is 2mm.

[0083] 4. Observation of injection molded color swatches: A hazy appearance indicates the presence of low molecular weight substances such as solvents.

[0084] Table 1: Performance test results of polyamide etherimide products in the examples and comparative examples

[0085]

[0086] As can be seen from the above embodiments, the polyamide ether imide polymer preparation method of the present invention adopts a continuous reactive extrusion process, which is simple and efficient (the reaction residence time can be reduced to less than 30 minutes), and avoids the use of organic solvents. The product has high purity and does not require further purification treatment such as solvent removal and small molecule removal. It fundamentally solves the problem of purity defects and performance degradation caused by solvent residue in traditional processes, and produces polyamide ether imide products with stable quality that are suitable for industrial production.

[0087] The polyamide ether imide material prepared by the method of this invention has high heat resistance and excellent comprehensive properties, as well as high fluidity and good processability, making it suitable for the preparation of thin-walled parts and precision parts in the field of precision manufacturing.

[0088] Comparative Example 1 uses a traditional organic solvent system polymerization method. Although the solvent was removed afterward, the injection-molded color plate appeared yellow, hazy, and transparent. Moreover, its heat resistance and mechanical properties were deteriorated compared to Example 1. This indicates that the solvent residue in the product prepared by the traditional method is difficult to completely eliminate, which leads to purity defects and performance degradation.

Claims

1. A method for preparing polyamide ether imide, characterized in that, Includes the following steps: Diamine monomer, trimellitic anhydride chloride and end-capping agent are added to an extrusion reaction device in a stoichiometric ratio, and the reaction is carried out at 100~400℃. The mixture is then extruded, granulated and prepared to obtain polyamide ether imide. The molar ratio of the diamine monomer to trimellitic anhydride acyl chloride is 0.95:1.05~1.05:0.95; the amount of the capping agent is 0.1~1 mol of the diamine monomer.

2. The method for preparing polyamide ether imide according to claim 1, characterized in that, The diamine monomer is selected from aromatic diether diamines; preferably, the diamine monomer is selected from at least one of the following: 。 3. The method for preparing polyamide ether imide according to claim 1, characterized in that, The diamine monomer is selected from at least one of the following: 。 4. The method for preparing polyamide ether imide according to claim 1, characterized in that, The end-capping agent is selected from at least one of amine end-capping agents, anhydride end-capping agents, or acyl chloride end-capping agents; the amine end-capping agent is selected from any one of monofunctional aliphatic amines with 1-10 carbon atoms, aniline, benzidine, diphenyl etheramine, and cyclohexylamine; the anhydride end-capping agent is selected from any one of phthalic anhydride and naphthalene anhydride; and the acyl chloride end-capping agent is selected from benzoyl chloride.

5. The method for preparing polyamide ether imide according to claim 1, characterized in that, The end-capping agent is mixed with the diamine monomer and then simultaneously enters the extrusion reaction equipment, or the end-capping agent is mixed with trimellitic anhydride chloride and then simultaneously enters the extrusion reaction equipment, or the end-capping agent enters the reaction system separately at the end of the extrusion reaction equipment in the form of a liquid column or gas; preferably, the end-capping agent enters the reaction system separately at the end of the extrusion reaction equipment in the form of a liquid column or gas.

6. The method for preparing polyamide ether imide according to claim 1, characterized in that, The extrusion reaction equipment includes a feeding section, a mixing section, a polymerization section, a post-polymerization section, and a discharge section; the temperature of the feeding section is controlled at 100℃-200℃, the temperature of the mixing section is controlled at 150℃-250℃, the temperature of the polymerization section and the post-polymerization section is controlled at 200℃-400℃, and the temperature of the discharge section is controlled at 300-360℃.

7. The method for preparing polyamide ether imide according to claim 6, characterized in that, The extrusion reaction equipment is equipped with exhaust ports in the feeding section, mixing section, polymerization section, and post-polymerization section. The pressure in the feeding section and mixing section is controlled at 0 to -0.08 MPa, the pressure in the polymerization section is controlled at -0.06 MPa to -0.9 MPa, and the pressure in the post-polymerization section is controlled at -0.09 MPa to -0.1 MPa.

8. The method for preparing polyamide ether imide according to claim 6, characterized in that, The material residence time in the extrusion reaction equipment is 3-20 min, preferably 5-15 min.

9. The method for preparing polyamide ether imide according to claim 1, characterized in that, The reactive extrusion equipment is selected from any one of a single-screw extruder, a twin-screw extruder, a three-screw extruder, a planetary screw extruder, and a continuous mixer; the length-to-diameter ratio (L / D) of the barrel of the extrusion reactive equipment is greater than 40:

1.

10. A polyamide ether imide material, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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