CN118580485A - Preparation method of continuous extrusion reactive melt-tackified polyetheretherketone - Google Patents

Abstract

The invention relates to the technical field of molecular material processing, and in particular to a method for preparing a continuously extruded reactive melt-tackified polyetheretherketone, comprising the following steps: S1, first polymerizing to form a PEEK polymer; S2, configuring the PEEK polymer, a heat stabilizer, and an end-capping agent in proportion, performing melt blending extrusion and granulation at 340-380 DEG C, and continuously extruding to obtain the reactive melt-tackified polyetheretherketone; the invention forms the PEEK polymer first, and then performs reactive melt-tackification on the PEEK polymer, so as to effectively control the color difference between different batches of PEEK products and control the viscosity difference within a relatively low range, thereby improving the uniformity of the PEEK product.

Description

Preparation method of continuous extrusion reactive melt-tackified polyetheretherketone

Technical Field

The invention relates to the technical field of polymer material processing, in particular to a method for preparing continuously extruded reactive melt-tackified polyetheretherketone.

Background Art

Polyetheretherketone (PEEK) material has excellent comprehensive properties of wear resistance, mechanical strength, high temperature resistance and easy molding and processing. It is recognized as the material with the best comprehensive performance that can be processed using thermoplastic equipment.

The polymerization process of PEEK materials mainly includes polymerization, purification, drying, and processing, among which polymerization is the core process. The polymerization process is to melt and mix the raw materials and add them to the polymerization kettle, and then carry out the polymerization reaction at 280℃-340℃ for 8-12 hours. In the long-term high-temperature polymerization reaction, PEEK materials are prone to degradation and cross-linking in a high-temperature environment, and the by-products produced by degradation and cross-linking will have serious adverse consequences for subsequent molding and processing. Among them, PEEK containing large branched segments and ultra-large molecular weight forms gels, which will produce defects such as fish eyes when extruding films or cables, while low-molecular-weight PEEK may produce black spots during the processing due to insufficient heat resistance. Secondly, the polymerization process of PEEK means that each kettle is a batch, and the viscosity, color difference, and molecular weight consistency between each batch are difficult to guarantee. In addition, during the PEEK reaction process, the temperature is controlled by multi-stage heating, and the heating rate, control temperature, and duration of each stage need to be precisely controlled. As the polymerization reaction reaches the later stage, the viscosity in the reactor is huge, and the precise control of the temperature in the reactor will become extremely difficult.

Summary of the invention

In view of the problems of many byproducts, high system viscosity and difficult to control performance between batches in the existing PEEK polymerization technology, a method for preparing polyetheretherketone by continuous extrusion reactive melt viscosity enhancement is provided. The present invention forms a PEEK polymer first and then performs reactive melt viscosity enhancement on it, which can effectively control the color difference between different batches of PEEK products and control the viscosity difference within a relatively low range, thereby improving the uniformity of PEEK products.

In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone comprises the following steps:

S1, first polymerize to form a PEEK polymer;

S2, the PEEK polymer, heat stabilizer and end-capping agent are mixed in proportion, melt-blended and extruded at 340-380° C., and granulated, and the reactive melt-tackified polyetheretherketone is obtained by continuous extrusion.

Furthermore, the melt index of the PEEK polymer is 2-100 g/10 min, and the melt index is measured at 400° C. and a load of 2.16 kg.

Furthermore, the synthesis method of the PEEK polymer is: placing a solvent in a reaction kettle, heating it to 140-170° C. under a protective atmosphere, and adding difluorobenzophenone, hydroquinone, and an acid binding agent after the temperature is constant, mixing them well, and heating them to 300-320° C. to carry out a polymerization reaction to obtain the PEEK polymer.

Furthermore, the specific process of the polymerization reaction is: after the materials to be reacted are evenly mixed, the temperature is increased to 240-260°C at a rate of 0.1-10°C/min and then kept warm for reaction for 30-80 minutes, then the temperature is increased to 300-320°C at a rate of 0.1-10°C/min and then kept warm for reaction for at least 30 minutes, and then water is added to precipitate solids, and the solids are separated, washed, and dried to obtain PEEK polymer.

Preferably, the solvent is one or more of diphenyl sulfone, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, 1-methyl-2-pyrrolidone, and dimethyl sulfoxide;

The acid binding agent is sodium carbonate and/or potassium carbonate;

The molar ratio of the difluorobenzophenone to the hydroquinone is 1.00-1.08:1; the molar ratio of the acid binding agent to the hydroquinone is 0.9-1.2:1; the amount of the solvent is 1.2-2 times the total weight of the difluorobenzophenone, the hydroquinone and the acid binding agent;

Keep the reaction at 300-320℃ for 40min-5h.

Furthermore, the heat stabilizer is a phosphate compound; the amount of the heat stabilizer is 0.01%-1% of the weight of the PEEK prepolymer;

The end-capping agent is selected from difluoro compounds, phenolic compounds and metal salts, and the amount of the end-capping agent is 0.01%-2% of the weight of the PEEK prepolymer.

Preferably, the phosphate compound is selected from one or more of calcium phosphate, calcium hypophosphite, potassium hydrogen phosphate, potassium pyrophosphate, and potassium polymetaphosphate;

The difluoro compound is selected from difluorobenzophenone, 1,4-bis(4'-fluorobenzoyl)benzene, and 1,3-bis(4'-fluorobenzoyl)benzene; the phenolic compound is selected from phenol, hydroquinone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxybiphenyl, and 4,4'-dihydroxydiphenyl ether; the metal salt is selected from one or more of halides and sulfates, wherein the metal is selected from one or more of lithium, magnesium, barium, calcium, and strontium, such as lithium chloride, calcium chloride, magnesium chloride, lithium bromide, lithium iodide, lithium sulfate, etc.

Furthermore, the melt blending extrusion adopts a twin-screw extruder, the screw diameter of the twin-screw extruder is greater than 60 mm, the aspect ratio L/D of the screw is greater than 50, and the barrel has a forced side feeding port.

Furthermore, the heat stabilizer and the end-capping agent are added at the forced side feeding port.

Furthermore, the extrusion process parameters are: main machine speed 100-600rpm, barrel temperature set to 340-380°C, and extrusion output 100-600kg/h.

Furthermore, the cylinder has a total of 15 heating temperature zones, the forced side feeding port is arranged in the 7th section, and a vacuum exhaust port is arranged in the 12th section and the 13th section respectively. The temperature settings of each temperature zone are as follows: 340℃, 350℃, 350℃, 350℃, 355℃, 360℃, 360℃, 365℃, 365℃, 370℃, 370℃, 370℃, 370℃, 370℃, 365℃, and the temperature of each temperature zone fluctuates up and down by 10℃.

Beneficial technical effects:

In view of the problems of many by-products, high system viscosity and difficult to control performance between batches in the existing PEEK polymerization technology, the present invention first synthesizes polymers with different polymerization degrees, and then uses a twin-screw extruder to perform reactive melt viscosity enhancement. By utilizing the efficient and uniform mixing effect of the twin-screw extruder, under the action of a thermal stabilizer, a capping agent, etc., the reactive viscosity enhancement of the PEEK material is completed in the extruder barrel, thereby obtaining a series of PEEK resins with expected viscosities to meet the use requirements of subsequent molding processes such as extrusion and injection molding, and also effectively avoiding the defect of excessive by-products caused by long-term high-temperature reaction of the PEEK material in the traditional polymerization process, which affects the product quality.

The present invention can also effectively reduce the color and viscosity differences between different batches of PEEK products and improve the uniformity of PEEK products by mixing and extruding PEEK polymers from different production batches for melt viscosity enhancement;

The twin-screw extruder has high speed, high mixing capacity, and good exhaust and devolatilization effect, which can avoid the defects of excessive viscosity of PEEK in the polymerization kettle in the late stage of traditional polymerization and poor control of system temperature. The strong exhaust function can effectively remove small molecules such as moisture and by-products generated by PEEK in the reactive viscosity increasing process, thereby improving product quality.

DETAILED DESCRIPTION

The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. The technology and method known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and method should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

The experimental methods in the following examples without specifying specific conditions are usually measured in accordance with national standards; if there is no corresponding national standard, they are carried out in accordance with general standard requirements or general methods.

Comparative Example 1

The synthesis of PEEK in this case is a conventional staged temperature-raising polymerization method, and the specific method is as follows:

Under nitrogen protection, add 1100kg of diphenyl sulfone to a ^3m3 polymerization reactor, heat to 140℃, and after diphenyl sulfone is completely melted, add 370kg of 4,4'-difluorobenzophenone, 183kg of hydroquinone, and 200kg of sodium carbonate (200 mesh) in sequence. After mixing evenly, heat to 250℃ for 90min and keep the reaction at this temperature for 60min.

Then the temperature was raised to 310°C over 90 min and kept at this temperature for 3 h;

Then, 30 g of hydroquinone was added to adjust the molecular weight, and the reaction was continued at 310°C for 0.5 h;

Then, 2.5 kg of 4,4'-difluorobenzophenone was added, and the end-capping reaction was continued at 310°C for 1 h;

The reacted material was poured into cold distilled water to obtain a white solid block, which was crushed with a grinder, washed with acetone 5 times to remove the solvent and unreacted capping agent, raw materials, etc., and washed with distilled water 5 times to remove inorganic salts generated by the reaction to obtain a white solid. PEEK was obtained after drying, and the total amount of the product was about 400 kg.

Using the same synthesis process as in this case, five batches of PEEK were synthesized, and the performance data of each batch are shown in Table 1.

Example 1

The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone comprises the following steps:

S1, first polymerize to form PEEK polymer:

Under nitrogen protection, add 1100kg of diphenyl sulfone to a ^3m3 polymerization reactor, heat to 140℃, and after diphenyl sulfone is completely melted, add 370kg of 4,4'-difluorobenzophenone, 183kg of hydroquinone, and 200kg of sodium carbonate (200 mesh) in sequence. After mixing evenly, heat to 250℃ for 90min and keep the reaction at this temperature for 60min.

Then the temperature was raised to 310°C for 90 minutes and kept at this temperature for 2 hours; the reacted material was poured into cold distilled water to obtain a white block solid, which was crushed with a grinder, washed with acetone for 5 times to remove the solvent and unreacted materials, and washed with distilled water for 5 times to remove inorganic salts generated by the reaction to obtain a white powder, which was dried to obtain a powdered PEEK polymer;

S2. Reactive melt viscosity increasing using a twin-screw extruder:

Twin-screw extruder, screw diameter 75mm, length-to-diameter ratio L/D=60, barrel with 15 heating temperature zones, forced side feeding port at section 7, vacuum exhaust port at sections 12 and 13;

Add 400 kg of dried PEEK polymer into the main feed hopper of the twin-screw extruder;

0.8 kg of calcium phosphate heat stabilizer and 0.4 kg of 4,4'-difluorobenzophenone end-capping agent were mixed in proportion and then added to the seventh forced side feeding port of the twin-screw extruder;

The temperatures of each temperature zone are set according to the processing direction as follows: 340°C, 350°C, 350°C, 350°C, 355°C, 360°C, 360°C, 365°C, 365°C, 370°C, 370°C, 370°C, 370°C, 370°C, 365°C. The main engine speed is set to 400rpm and the extrusion output is 300kg/h. Stabilizer and end capping agent are added by side feeding. After melt blending and continuous extrusion, air cooling and pelletizing, reactive melt-tackified polyetheretherketone is obtained.

Using the same preparation process as in this case, five batches of PEEK were prepared, and the performance data of each batch are shown in Table 1.

Example 2

The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone comprises the following steps:

S1, first polymerize to form PEEK polymer:

Under nitrogen protection, add 1100kg of diphenyl sulfone to a ^3m3 polymerization reactor, heat to 140℃, and after diphenyl sulfone is completely melted, add 370kg of 4,4'-difluorobenzophenone, 183kg of hydroquinone, and 200kg of sodium carbonate (200 mesh) in sequence. After mixing evenly, heat to 250℃ for 90min and keep the reaction at this temperature for 60min.

Then the temperature was raised to 310°C for 90 minutes and kept at this temperature for 3 hours; the reacted material was poured into cold distilled water to obtain a white block solid, which was crushed with a grinder, washed with acetone 5 times to remove the solvent and unreacted materials, and washed with distilled water 5 times to remove inorganic salts generated by the reaction to obtain a white powder, which was dried to obtain a powdered PEEK polymer;

S2. Reactive melt viscosity increasing using a twin-screw extruder:

Twin-screw extruder, screw diameter 75mm, length-to-diameter ratio L/D=60, barrel with 15 heating temperature zones, forced side feeding port at section 7, vacuum exhaust port at sections 12 and 13;

Add 400 kg of dried PEEK polymer into the main feed hopper of the twin-screw extruder;

1 kg of calcium phosphate heat stabilizer and 0.45 kg of hydroquinone end-capping agent were mixed in proportion and then added to the 7th forced side feeding port of the twin-screw extruder;

The temperatures of each temperature zone are set according to the processing direction as follows: 350°C, 355°C, 355°C, 355°C, 360°C, 365°C, 365°C, 370°C, 375°C, 375°C, 375°C, 375°C, 375°C, 375°C, 370°C. The main engine speed is set to 300rpm, the extrusion output is 200kg/h, the stabilizer and the end capping agent are added by side feeding, and the product is continuously extruded after melt blending and air cooling and pelletizing to obtain reactive melt-tackified polyetheretherketone.

Using the same preparation process as in this case, five batches of PEEK were prepared, and the performance data of each batch are shown in Table 1.

Example 3

The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone comprises the following steps:

S1, first polymerize to form PEEK polymer:

Under nitrogen protection, add 1100kg of diphenyl sulfone to a ^3m3 polymerization reactor, heat to 140℃, and after diphenyl sulfone is completely melted, add 370kg of 4,4'-difluorobenzophenone, 183kg of hydroquinone, and 200kg of sodium carbonate (200 mesh) in sequence. After mixing evenly, heat to 250℃ for 90min and keep the reaction at this temperature for 60min.

Then the temperature was raised to 310°C for 90 minutes and kept at this temperature for 1 hour; the reacted material was poured into cold distilled water to obtain a white block solid, which was crushed with a grinder, washed with acetone 5 times to remove the solvent and unreacted materials, and washed with distilled water 5 times to remove inorganic salts generated by the reaction to obtain a white powder, which was dried to obtain a powdered PEEK polymer;

S2. Reactive melt viscosity increasing using a twin-screw extruder:

Twin-screw extruder, screw diameter 75mm, length-to-diameter ratio L/D=60, barrel with 15 heating temperature zones, forced side feeding port at section 7, vacuum exhaust port at sections 12 and 13;

Add 400 kg of dried PEEK polymer into the main feed hopper of the twin-screw extruder;

0.3 kg of calcium phosphate heat stabilizer and 0.2 kg of hydroquinone end-capping agent were mixed in proportion and then added to the seventh forced side feeding port of the twin-screw extruder;

The temperatures of each temperature zone are set according to the processing direction as follows: 350°C, 355°C, 355°C, 355°C, 360°C, 365°C, 365°C, 370°C, 370°C, 375°C, 375°C, 375°C, 375°C, 375°C, 370°C. The main engine speed is set to 500rpm, the extrusion output is 400kg/h, the stabilizer and the end capping agent are added by side feeding, and the reactive melt-thickening polyetheretherketone is obtained after melt blending and continuous extrusion and air cooling and pelletizing.

Using the same preparation process as in this case, five batches of PEEK were prepared, and the performance data of each batch are shown in Table 1.

Table 1 PEEK performance of each batch in each case

(Note: The calculation method of the difference ratio is: the ratio of the absolute value of the difference between the maximum and minimum values of the item to the average value. The smaller the difference ratio, the smaller the data fluctuation, the better the data stability, and the more stable the product performance)

As can be seen from the data, the method of the present invention can obtain a series of PEEK resins with expected viscosities by first synthesizing a PEEK polymer and then performing reactive melt viscosity enhancement under the action of a thermal stabilizer and a capping agent, which can effectively avoid the defect of excessive by-products caused by long-term high-temperature reaction of PEEK materials in traditional polymerization processes, affecting product quality (the data difference ratio of comparative example 1 is large). The present invention can effectively control the color difference between different batches of PEEK products and control the viscosity difference within a lower range, thereby improving the uniformity of PEEK products. The viscosity and color difference consistency of each batch of PEEK of the present invention are good.

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 scheme and inventive concept 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 (10)

1. A method for preparing a continuous extrusion reactive melt-tackified polyetheretherketone, characterized in that it comprises the following steps: S1, first polymerize to form a PEEK polymer; S2, the PEEK polymer, heat stabilizer and end-capping agent are mixed in proportion, melt-blended and extruded at 340-380° C., and granulated, and the reactive melt-tackified polyetheretherketone is obtained by continuous extrusion. 2. The method for preparing continuously extruded reactive melt-tackified polyetheretherketone according to claim 1 is characterized in that the melt index of the PEEK polymer is 2-100 g/10 min, and the melt index is measured at 400° C. and 2.16 kg load. 3. The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone according to claim 2 is characterized in that the synthesis method of the PEEK polymer is: placing a solvent in a reaction kettle, heating it to 140-170°C under a protective atmosphere, and adding difluorobenzophenone, hydroquinone, and an acid binding agent after the temperature is constant, mixing them evenly, and then heating the mixture to 300-320°C for polymerization to obtain a PEEK polymer. 4. The method for preparing continuously extruded reactive melt-thickened polyetheretherketone according to claim 3 is characterized in that the specific process of the polymerization reaction is: after the materials to be reacted are mixed evenly, the temperature is increased to 240-260°C at a rate of 0.1-10°C/min and then kept warm for reaction for 30-80 minutes, then the temperature is increased to 300-320°C at a rate of 0.1-10°C/min and then kept warm for reaction for at least 30 minutes, then water is added to precipitate solids, the solids are separated, washed, and dried to obtain PEEK polymer. 5. The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone according to claim 3, characterized in that the solvent is one or more of diphenyl sulfone, cyclopentane, N,N-dimethylformamide, N,N-dimethylacetamide, 1-methyl-2-pyrrolidone, and dimethyl sulfoxide; The acid binding agent is sodium carbonate and/or potassium carbonate; The molar ratio of the difluorobenzophenone to the hydroquinone is 1.00-1.08:1; the molar ratio of the acid binding agent to the hydroquinone is 0.9-1.2:1; and the amount of the solvent used is 1.2-2 times the total weight of the difluorobenzophenone, the hydroquinone and the acid binding agent. 6. The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone according to any one of claims 1 to 5, characterized in that the heat stabilizer is a phosphate compound; the amount of the heat stabilizer is 0.01%-1% of the weight of the PEEK prepolymer; The end-capping agent is selected from difluoro compounds, phenolic compounds and metal salts, and the amount of the end-capping agent is 0.01%-2% of the weight of the PEEK prepolymer. 7. The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone according to claim 6, characterized in that the phosphate compound is selected from one or more of calcium phosphate, calcium hypophosphite, potassium hydrogen phosphate, potassium pyrophosphate, and potassium polymetaphosphate; The difluoro compound is selected from difluorobenzophenone, 1,4-bis(4'-fluorobenzoyl)benzene, and 1,3-bis(4'-fluorobenzoyl)benzene; the phenolic compound is selected from phenol, hydroquinone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxybiphenyl, and 4,4'-dihydroxydiphenyl ether; the metal salt is selected from one or more of halides and sulfates, wherein the metal is selected from one or more of lithium, magnesium, barium, calcium, and strontium. 8. The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone according to any one of claims 1 to 5, characterized in that the melt blending extrusion adopts a twin-screw extruder, the screw diameter of the twin-screw extruder is greater than 60 mm, the aspect ratio L/D of the screw is greater than 50, and the barrel has a forced side feeding port; The heat stabilizer and the end-capping agent are added at the forced side feeding port. 9. The method for preparing a continuously extruded reactive melt-tackified polyetheretherketone according to any one of claims 1 to 5, characterized in that the extrusion process parameters are: main engine speed 100-600 rpm, barrel temperature set to 340-380°C, and extrusion output 100-600 kg/h. 10. The method for preparing continuously extruded reactive melt-thickened polyetheretherketone according to claim 9 is characterized in that the cylinder has a total of 15 heating temperature zones, the forced side feeding port is arranged in the 7th section, and a vacuum exhaust port is arranged in the 12th section and the 13th section respectively, and the temperature of each temperature zone is set as follows: 340°C, 350°C, 350°C, 350°C, 355°C, 360°C, 360°C, 365°C, 365°C, 370°C, 370°C, 370°C, 370°C, 370°C, 365°C, and the temperature of each temperature zone fluctuates up and down by 10°C.