Final polycondensation reactor for preparing high-quality high-viscosity PA66 polymer

Abstract

The invention belongs to the field of polymeric high-molecular polymer production equipment, and relates to a final polycondensation reactor for preparing a high-quality and high-viscosity PA66 polymer, the final polycondensation reactor comprises a shell and a stirring device located in the shell, and the shell is provided with a feed port, a discharge port and a gas phase port; the shell comprises an inner layer and an outer layer, and an area between the inner layer and the outer layer forms a jacket layer; the inner layer of the shell is composed of a cylinder I and a cylinder II, and the diameter of the cylinder I is larger than that of the cylinder II. One bottom surface of the cylinder I and one bottom surface of the cylinder II are intersected and overlapped areas are communicated with each other; the position of the feed port is higher than that of the discharge port; the stirring device consists of a transmission shaft and a stirrer; the first stirrer consists of a disc and a spiral belt fixed on the disc; the second stirrer comprises a spiral structural member; and the third stirrer comprises a spiral propeller. According to the invention, the continuous propulsion of the polymer melt in the final polycondensation process is realized, the backmixing of the high-viscosity polymer melt is prevented, and the retention time consistency of the polymer melt is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high polymer production equipment, and relates to a terminal polycondensation reactor for preparing high-quality high-viscosity PA66 polymers. BACKGROUND

[0002] The technical path for producing polyhexamethylene adipamide (PA66) in the industry mainly uses the water solution high-pressure polycondensation method, which includes processes such as salting, concentration, pre-polymerization, flash, and terminal polycondensation. The entire production process includes different types of equipment, among which the terminal polycondensation reactor is the key equipment in the entire process, which is used to complete the PA66 terminal polycondensation step and plays a decisive role in the quality of the polyamide 66 product.

[0003] The existing terminal polycondensation reactor for continuously producing high-viscosity polyamide 66 in the industry is usually a vertical stirring reactor. Although this type of reactor is equipped with auxiliary devices such as scrapers and liquid level stabilizers, back mixing of the melt inevitably occurs during continuous production, resulting in inconsistent residence time of the polymer in the terminal polycondensation reactor, large fluctuations in the molecular weight of the produced PA66, low product quality, and limited application range, especially the inability to meet the application requirements in the high-quality high-strength fiber field.

[0004] In order to solve the problem of back mixing in the vertical stirring reactor, horizontal reactors are also used to prepare high-viscosity polymers. For example, the patents with authorization announcement numbers CN110280202B and CN111672443B use a combined stirrer structure to prepare high-viscosity polymers. In the high-viscosity area, a spiral or its equivalent structure is used to forcibly push the melt towards the discharge port. However, the stirrer shell in the above-mentioned patents is a cylindrical cylinder, which has the following disadvantages: the utilization rate of the stirrer is low in the high-viscosity area, and the large area of the spiral stirrer easily brings excessive high-viscosity polymer during membrane drawing, which increases the thickness of the liquid film and leads to poor devolatilization effect. In addition, the excessive high-viscosity polymer on the stirrer cannot be updated in time, resulting in inconsistent residence time and even affecting thermal degradation; there is no effective measure to prevent back mixing of the melt in the medium and high-viscosity areas of the polymerizer. Therefore, the quality uniformity of the high-viscosity PA66 produced by the above-mentioned method still cannot meet the high-quality requirements.

[0005] Therefore, it is of great significance to research a terminal polycondensation reactor for preparing high-quality high-viscosity PA66 polymers to solve the above-mentioned problems. SUMMARY

[0006] The purpose of the present application is to solve the problems existing in the prior art and provide a terminal polycondensation reactor for preparing high-quality high-viscosity PA66 polymers.

[0007] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0008] A final polycondensation reactor for preparing high-quality high-viscosity PA66 polymer, the relative viscosity (tested according to the standard HG / T 4182-2012, sulfuric acid method) of the high-viscosity PA66 polymer is greater than or equal to 2.8; the final polycondensation reactor is a horizontal reactor, comprising a shell and a stirring device located inside the shell, the shell is provided with a feed inlet, a discharge outlet and a gas phase port; the shell comprises an inner layer and an outer layer, the inner layer and the outer layer have the same shape, the area between the inner layer and the outer layer forms a jacket layer, the jacket layer is used to contain heat medium; the inner layer of the shell is composed of a cylindrical barrel I and a cylindrical barrel II, one bottom surface of the cylindrical barrel I and one bottom surface of the cylindrical barrel II intersect, and the overlapping area of the two bottom surfaces is in communication with each other, and the remaining areas are respectively sealed; the side surfaces of the cylindrical barrel I and the cylindrical barrel II are parallel to the horizontal plane, and the position of the feed inlet is higher than that of the discharge outlet, so that not only the liquid level adjustment function is achieved from the structure, but also the back mixing of high-viscosity polymer to medium-viscosity polymer is prevented, the product quality of PA66 is effectively improved, the equipment is simple, the cost is reduced, and it is especially suitable for preparing high-quality high-viscosity PA66 polymer; there is no special requirement for the diameters of the cylindrical barrel I and the cylindrical barrel II, as long as the step height formed by the misalignment is greater than the melt liquid level to achieve the effect of preventing material back mixing; the area of the intersection part of the bottom surfaces of the cylindrical barrel I and the cylindrical barrel II (i.e. the overlapping area) can be calculated according to the actual yield and size;

[0009] The stirring device is composed of a transmission shaft and a stirrer fixed on the transmission shaft;

[0010] The transmission shaft comprises a transmission shaft I and a transmission shaft II, the transmission shaft I is fixed in the cylindrical barrel I, and the transmission shaft II is fixed in the cylindrical barrel II;

[0011] The stirrer comprises a first stirrer close to the feed inlet, a third stirrer close to the discharge outlet and a second stirrer located between the first stirrer and the third stirrer; the first stirrer and the second stirrer are fixed on the transmission shaft I, and the third stirrer is fixed on the transmission shaft II; the three stirrers divide the final polycondensation reactor from the feed inlet to the discharge outlet into different viscosity zones in turn, i.e. the first stirrer corresponds to the low-viscosity zone, the second stirrer corresponds to the medium-viscosity zone, and the third stirrer corresponds to the high-viscosity zone;

[0012] The first stirrer is composed of a plurality of center-holed discs and a plurality of spiral belts fixed on the discs, and the plurality of discs are fixed concentrically and equidistantly on the transmission shaft I through the holes in the center; under the action of the first stirrer, the low-viscosity polymer melt is continuously pushed forward, and a large number of liquid films are formed on the disc surfaces in the rotating process, the curved frame formed by the spiral belt and the disc can also have a film-pulling effect, which can promote the devolatilization of small molecular by-products, thereby strengthening the polymerization reaction, preventing the polymer melt from mixing and adhering, improving the consistency of the polymer melt residence time, and the spiral belt can also provide an axial pushing force for the polymer in the melt pool, so that the polymer melt residence time can be controlled by adjusting the stirring speed of the stirrer;

[0013] The second stirrer comprises a spiral structure fixed on the transmission shaft I;

[0014] The third stirrer comprises a spiral propeller fixed on the transmission shaft II;

[0015] The present application sets three different structure stirrers according to the viscosity change in the polymerization process, which aims to match the viscosity change of the polymer in the polymerization process, control the polymer liquid film area and liquid film thickness on the stirrer, enhance the mass transfer effect, and realize the thermodynamic strengthening of the polymerization process.

[0016] When the low-viscosity polymer melt enters the cylindrical barrel I from the feeding port, since its diameter is larger than that of the cylindrical barrel II, a larger-diameter stirrer can be arranged, so that the film-pulling area is larger, which is beneficial to the devolatilization of small molecules and the strengthening of the polymerization reaction, and as the polymerization reaction proceeds, the polymer viscosity gradually increases and enters the smaller-diameter cylindrical barrel II, and the diameter of the stirrer arranged therein is also smaller, so that the polymer viscosity can be matched, and the formation of too thick liquid film on the stirrer by the high-viscosity polymer is prevented, which affects the devolatilization of small molecules.

[0017] As a preferred technical solution:

[0018] The terminal polycondensation reactor for preparing high-quality high-viscosity PA66 polymer as described above, the diameter of the cylindrical barrel I is larger than that of the cylindrical barrel II; the feeding port is arranged at the bottom of the side surface of the cylindrical barrel I away from the cylindrical barrel II, the discharge port is arranged at the bottom of the side surface of the cylindrical barrel II away from the cylindrical barrel I, and the gas phase port is arranged at the top of the side surface of the cylindrical barrel II away from the cylindrical barrel I.

[0019] The terminal polycondensation reactor for preparing high-quality high-viscosity PA66 polymer as described above, the transmission shaft I is sealingly fixed on both sides of the axial direction of the cylindrical barrel I, and extends a certain distance from the bottom surface which does not intersect with the cylindrical barrel II (the setting of the distance has no particular requirement, as long as it can be mechanically connected with a stirring motor) for connecting a stirring motor;

[0020] The transmission shaft II is sealed and fixed on both sides of the axial direction of the cylindrical barrel II, and extends a certain distance from the bottom surface which does not intersect with the cylindrical barrel I (the setting of the distance has no special requirements, as long as it can be mechanically connected with the stirring motor) for connecting another stirring motor;

[0021] The fixed position of the transmission shaft I is not higher than the center line of the cylindrical barrel I, and the transmission shaft I is parallel to the center line of the cylindrical barrel I;

[0022] The fixed position of the transmission shaft II is not higher than the center line of the cylindrical barrel II, and the transmission shaft II is parallel to the center line of the cylindrical barrel II;

[0023] The parallelism of the fixed positions of the transmission shaft I and the transmission shaft II to the center lines of the cylindrical barrel I and the cylindrical barrel II respectively can make the three stirrers more closely fit the inner wall of the final polycondensation reactor (i.e., the spacings between the three stirrers and the inner wall of the final polycondensation reactor are equal), and the gap is stable during rotation, avoiding the extension of the residence time caused by the uneven thickness of the polymer melt adhering to the inner wall of the reactor.

[0024] The final polycondensation reactor for preparing high-quality and high-viscosity PA66 polymer as described above, the disc surface is divided into a plurality of fan-shaped hole regions and a plurality of fan-shaped partition regions, and the plurality of hole regions and the plurality of partition regions are alternately distributed along the circumferential direction of the disc; a plurality of spiral belts are used to connect a plurality of discs; the hole regions on any adjacent discs do not completely overlap, so that the first stirrer composed of a plurality of discs cannot directly pass through the polymer, and the residence time of the polymer can be controlled by adjusting the rotation speed of the stirrer.

[0025] The final polycondensation reactor for preparing high-quality and high-viscosity PA66 polymer as described above, the disc diameter is constant from the feed inlet to the discharge outlet, so that the first stirrer is more closely fitted with the cylindrical barrel I (i.e., the spacings between the first stirrer and the cylindrical barrel I are equal), preventing the extension of the residence time caused by the polymer adhering to the inner layer of the final polycondensation reactor, and even preventing adverse conditions such as thermal degradation; the area ratio of the hole region of the disc gradually increases, so as to match the characteristics of the gradually deteriorating flowability of the polymer, thereby controlling the amount of polymer in the membrane pulling process to prevent the liquid film from being too thick;

[0026] The distance between all the discs and the inner wall of the cylindrical barrel I is equal, i.e., the axes of all the discs are concentric with the cylindrical barrel I.

[0027] A final polycondensation reactor for preparing high-quality and high-viscosity PA66 polymer as described above, a plurality of spiral belts are fixed on the edge of the disc or embedded in the partition area of the disc (the partition area is a solid area, and the spiral belt is embedded and fixed in the hole with the same cross-sectional shape of the spiral belt by opening a hole in the solid edge), and the plurality of discs are connected; the minimum distance between all spiral belts and the inner wall surface of the cylindrical barrel I is equal, in addition to the axial pushing effect of the above-mentioned spiral belt, it also plays the role of a scraper, which can prevent the extension of the residence time by scraping the polymer melt adhering to the inner layer of the final polycondensation reactor in the gap between the discs; the cross section of the spiral belt is streamline, preferably drop-shaped, which is beneficial to improve the scraping effect and the dripping of the polymer melt; the material of the spiral belt is nickel-plated stainless steel alloy.

[0028] A final polycondensation reactor for preparing high-quality and high-viscosity PA66 polymer as described above, the spiral structure includes a plurality of single-turn spiral blades, that is, the spiral blade is exactly one turn around the drive shaft within one pitch, and a plurality of single-turn spiral blades are concentrically and vertically fixed on the drive shaft I, so that the edge of the second stirrer can be more closely attached to the inner layer of the final polycondensation reactor, preventing the polymer from adhering to the inner layer of the reactor shell, thereby causing the extension of the residence time, even thermal degradation and other adverse conditions; from the feeding port to the discharge port, the diameter of the single-turn spiral blade is constant, and the pitch and the distance between adjacent single-turn spiral blades are gradually reduced, which takes into account the change of the polymer melt viscosity during polymerization. The spiral structure can control the liquid amount and the liquid film thickness on the spiral blade during the continuous advancement of the polymer melt, avoiding the problems of difficult devolatilization, increased residence time and other problems caused by excessive liquid film thickness; the minimum distance between all single-turn spiral blades and the inner wall surface of the cylindrical barrel I is equal.

[0029] A final polycondensation reactor for preparing high-quality and high-viscosity PA66 polymer as described above, the second stirrer further includes a plurality of thin rods, which are fixed to the edge of the single-turn spiral blade and connect all single-turn spiral blades; the projections of the plurality of thin rods and the drive shaft I on the horizontal plane are parallel, so that the plurality of thin rods and the single-turn spiral blade form a grid, which plays a role in membrane drawing, and the space below the grid is sufficient, which is beneficial to falling film and increases the devolatilization effect of small molecules, thereby strengthening the polymerization reaction; in addition, the axial thin rods of the surface grid also play the role of a scraper, which has the same effect as the spiral belt of the first stirrer described above, that is, to avoid the extension of the residence time and even thermal degradation and other adverse conditions caused by the adhesion of the polymer melt to the inner layer of the final polycondensation reactor, so that the polymer melt can be pushed towards the discharge port while improving the consistency of the residence time;

[0030] In addition, the first stirrer and the second stirrer of the present application are suitable for the change of polymer melt viscosity, have suitable film forming area and falling film effect, increase the devolatilization effect of small molecules, and further strengthen the polymerization reaction; meanwhile, the structure of the first and second stirrers of the present application enables the polymer melt to continuously advance towards the discharge port, the consistency of polymer residence time is improved, and the preparation of high quality polymer is facilitated.

[0031] The end-polycondensation reactor for preparing high quality high-viscosity PA66 polymer as described above, the helical propeller is composed of continuous helical blades, the continuous helical blades are vertically fixed on the transmission shaft II; from the feeding port to the discharge port, the diameter of the continuous helical blades is constant, and the pitch gradually decreases; the minimum distance between all the helical blades and the inner wall of the cylindrical barrel II is equal;

[0032] When the polymer melt reaches the third stirrer area, the mispositioned structure of the cylindrical barrel I and the cylindrical barrel II forcibly prevents back mixing, in addition, the third stirrer has a small diameter and a small amount of liquid during stirring, which can prevent a large amount of high-viscosity polymer from forming a too thick liquid film on the stirrer, thereby affecting the devolatilization of small molecules.

[0033] Beneficial effects:

[0034] (1) The present application can not only adjust the liquid level but also prevent the back mixing of high-viscosity polymer to medium-viscosity polymer by the design of the positions of the cylindrical barrel I and the cylindrical barrel II, effectively improves the quality of PA66 product, and has simple equipment and reduces cost.

[0035] (2) The present application realizes the continuous advancement of polymer melt during the end-polycondensation process, prevents the back mixing of high-viscosity polymer melt, and strengthens the thermodynamics of the polymerization process by the synergistic effect of the mispositioned shell of the horizontal reactor and the first, second and third stirrers with different structures, thereby improving the consistency of polymer melt residence time and facilitating the preparation of high quality high-viscosity polymer.

[0036] (3) The device of the present application has simple structure, saves the number of components, reduces the factory floor area and reduces cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 It is a schematic diagram of the end-polycondensation reactor for preparing high quality high-viscosity PA66 polymer of the present application;

[0038] Figure 2 It is a schematic diagram of the disc of the first stirrer of the present application; the blank area in the figure represents the hole area, and the shaded area represents the partition area;

[0039] Figure 3 It is a schematic diagram of the cross section of the helical belt of the present application;

[0040] Figure 4 It is a schematic diagram of the second stirrer of the present application;

[0041] In the figure, 1 - feed inlet, 2 - discharge outlet, 3 - gas phase port, 4 - cylindrical barrel I, 5 - cylindrical barrel II, 6 - first stirrer, 61 - disc, 62 - spiral belt, 63 - hole area, 64 - partition area, 7 - third stirrer, 8 - second stirrer, 81 - thin rod, 82 - single helix spiral blade, 9 - transmission shaft I, 10 - transmission shaft II. DETAILED DESCRIPTION

[0042] The application will be further described below in connection with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content taught by the application, and these equivalent forms also fall within the scope defined by the claims attached to the application.

[0043] The test methods of the relevant performance indicators in the following examples and comparative examples are as follows:

[0044] Relative viscosity: the prepared high-quality high-viscosity PA66 polymer is used as a sample, and then the sample is determined by the sulfuric acid method in the HG / T4182-2012 standard;

[0045] Molecular weight distribution: the prepared high-quality high-viscosity PA66 polymer is used as a sample, and then the sample is tested by gel chromatography; wherein, the test instrument is an Agilent 1260 type gel chromatograph, the chromatographic column is an Agilent HFIP series, the mobile phase is hexafluoroisopropanol and sodium trifluoroacetate, the concentration of sodium trifluoroacetate in the mobile phase is 0.02M, the test temperature is 40℃, and the sample is an Agilent PMMA narrow distribution standard.

[0046] Example 1

[0047] A final polycondensation reactor for preparing high-quality high-viscosity PA66 polymer is a horizontal reactor, as shown in Figures 1-4 which includes a shell and a stirring device located inside the shell;

[0048] The shell includes an inner layer and an outer layer, the inner layer and the outer layer have the same shape, and the area between the inner layer and the outer layer forms a jacket layer, which is used to contain heat medium;

[0049] The inner layer of the shell is composed of a cylindrical barrel I 4 and a cylindrical barrel II 5, the diameter of the cylindrical barrel I 4 is greater than the diameter of the cylindrical barrel II 5; one bottom surface of the cylindrical barrel I 4 and one bottom surface of the cylindrical barrel II 5 intersect, and the overlapping area of the two bottom surfaces is in communication with each other, and the remaining areas are respectively sealed;

[0050] The shell is provided with a feed inlet 1, a discharge outlet 2 and a gas phase port 3; the position of the feed inlet 1 is higher than that of the discharge outlet 2;

[0051] The feeding port 1 is arranged at the bottom of the side surface of the cylindrical barrel I 4 far from the cylindrical barrel II 5;

[0052] The discharging port 2 is arranged at the bottom of the side surface of the cylindrical barrel II 5 far from the cylindrical barrel I 4;

[0053] The gas phase port 3 is arranged at the top of the side surface of the cylindrical barrel II 5 far from the cylindrical barrel I 4;

[0054] The stirring device is composed of a transmission shaft and a stirrer fixed on the transmission shaft;

[0055] The transmission shaft comprises a transmission shaft I 9 and a transmission shaft II 10;

[0056] The transmission shaft I 9 is fixed on both sides of the axial direction of the cylindrical barrel I 4, and extends a certain distance from the bottom surface not intersecting the cylindrical barrel II 5 for connecting a stirring motor;

[0057] The fixed position of the transmission shaft I 9 is not higher than the center line of the cylindrical barrel I 4, and the transmission shaft I 9 is parallel to the center line of the cylindrical barrel I 4;

[0058] The transmission shaft II 10 is fixed on both sides of the axial direction of the cylindrical barrel II 5, and extends a certain distance from the bottom surface not intersecting the cylindrical barrel I 4 for connecting another stirring motor;

[0059] The fixed position of the transmission shaft II 10 is not higher than the center line of the cylindrical barrel II 5, and the transmission shaft II 10 is parallel to the center line of the cylindrical barrel II 5;

[0060] The stirrer comprises a first stirrer 6 close to the feeding port, a third stirrer 7 close to the discharging port, and a second stirrer 8 between the first stirrer 6 and the third stirrer 7;

[0061] The first stirrer 6 and the second stirrer 8 are fixed on the transmission shaft I 9, and the third stirrer 7 is fixed on the transmission shaft II 10;

[0062] As shown in Figure 1 , Figure 2 The first stirrer 6 is composed of a plurality of center-holed discs 61 and a plurality of spiral belts 62 fixed on the discs 61, and the plurality of discs 61 are concentrically and equidistantly fixed vertically on the transmission shaft I 9 through the holes in the center;

[0063] The surface of the disc 61 is divided into a plurality of hole regions 63 and a plurality of partition regions 64, and the plurality of hole regions 63 and the plurality of partition regions 64 are alternately distributed along the circumferential direction of the disc 61;

[0064] From the feeding port 1 to the discharging port 2, the diameter of the disc 61 is constant, and the area of the hole region 63 of the disc 61 gradually increases; the hole regions 63 on any adjacent discs 61 do not completely overlap;

[0065] The distance between all the discs 61 and the inner wall of the cylindrical barrel 4 is equal;

[0066] As shown in Figure 1 , Figure 3 The cross section of the spiral belt 62 is water-drop shaped, and the material is nickel-plated stainless steel alloy;

[0067] The spiral belts 62 are fixed on the edges of the discs 61 or embedded in the partition areas 64 of the discs 61 to connect the discs 61;

[0068] The minimum distance between all the spiral belts 62 and the inner wall of the cylindrical barrel 4 is equal;

[0069] As shown in Figure 1 , Figure 4 The second stirrer 8 comprises a spiral structure;

[0070] The spiral structure comprises a plurality of single-turn spiral blades 92 and thin rods 81;

[0071] The single-turn spiral blades 82 are concentrically and vertically fixed on the transmission shaft 19; from the feeding port 1 to the discharging port 2, the diameter of the single-turn spiral blades 82 is constant, the pitch and the distance between adjacent single-turn spiral blades 82 are gradually reduced, and the minimum distance between all the single-turn spiral blades 82 and the inner wall of the cylindrical barrel 4 is equal;

[0072] The thin rods 81 are fixed on the edges of the single-turn spiral blades 82 and connect all the single-turn spiral blades 82; the projections of the thin rods 81 and the transmission shaft 19 on the horizontal plane are parallel;

[0073] The third stirrer 7 comprises a spiral propeller;

[0074] The spiral propeller is composed of continuous spiral blades, which are vertically fixed on the transmission shaft 10;

[0075] From the feeding port to the discharging port, the diameter of the continuous spiral blades is constant, and the pitch is gradually reduced; the minimum distance between all the spiral blades and the inner wall of the cylindrical barrel 5 is equal.

[0076] Example 2

[0077] A method for preparing a high-quality and high-viscosity PA66 polymer, which uses the final polycondensation reactor for preparing a high-quality and high-viscosity PA66 polymer in Example 1, and the specific steps are as follows:

[0078] The pre-polymerized normal pressure melt (PA66 oligomer with a number average molecular weight of 10000 g / mol) is flowed into the final polycondensation reactor for preparing high quality and high viscosity PA66 polymer through the feeding port, and the melt gradually moves to the discharge port; wherein the melt temperature in the final polycondensation reactor for preparing high quality and high viscosity PA66 polymer is controlled at 283℃, the residence time of the melt in the cylindrical barrel I is 25 min, and the residence time of the melt in the cylindrical barrel II is 15 min, and the stirring rates of the three stirrers are 15 rpm, 15 rpm and 20 rpm respectively;

[0079] The parameters of the above-mentioned final polycondensation reactor for preparing high quality and high viscosity PA66 polymer are as follows:

[0080] The diameter of the cylindrical barrel I is 1.2 m, and the diameter of the cylindrical barrel II is 0.8 m;

[0081] The number of the discs is 3, the number of the helical strips on the discs is 4, the distance between the adjacent two discs is 1 m, and a single disc is composed of 6 hole regions and 6 partition regions;

[0082] From the feeding port to the discharge port direction, the area proportion of the hole region of the disc to the total area of the disc gradually increases, and is 40%, 50% and 60% respectively;

[0083] The helical strips are embedded in the partition regions of the discs at equal intervals;

[0084] The number of the single-turn helical blades is 3, and the number of the thin rods is 4;

[0085] The distance between the above-mentioned helical strips and thin rods and the inner wall surface of the cylindrical barrel I is 1 mm;

[0086] From the feeding port to the discharge port direction, the pitch of the adjacent single-turn helical blades is 1 m and 0.6 m respectively;

[0087] From the feeding port to the discharge port direction, the pitch of the adjacent continuous helical blades is 0.8 m, 0.6 m and 0.4 m respectively, and the distance between the helical blades and the inner wall surface of the cylindrical barrel II is 10 mm;

[0088] The relative viscosity of the finally prepared high viscosity PA66 polymer is 2.8, and the molecular weight distribution is 1.6.

Claims

1. A final polycondensation reactor for preparing high-quality high-viscosity PA66 polymer with a relative viscosity ≥ 2.8; the final polycondensation reactor is a horizontal reactor comprising a shell and a stirring device inside the shell, a feeding port (1), a discharging port (2) and a gas phase port (3) are arranged on the shell; characterized in that: The shell comprises an inner layer and an outer layer, the inner layer and the outer layer are of the same shape, and the area between the inner layer and the outer layer forms a jacket layer for accommodating heat medium; the inner layer of the shell is composed of a cylindrical barrel I and a cylindrical barrel II, one bottom surface of the cylindrical barrel I and one bottom surface of the cylindrical barrel II intersect, and the overlapping area of the two bottom surfaces is communicated with each other, and the remaining area is sealed respectively; the position of the feeding port (1) is higher than that of the discharging port (2); ​ The stirring device is composed of a transmission shaft and a stirrer fixed on the transmission shaft; The transmission shaft comprises a transmission shaft I (9) and a transmission shaft II (10), the transmission shaft I (9) is fixed in the cylindrical barrel I, and the transmission shaft II (10) is fixed in the cylindrical barrel II; The stirrer comprises a first stirrer (6) close to the feeding port, a third stirrer (7) close to the discharging port and a second stirrer (8) between the first stirrer (6) and the third stirrer (7); the first stirrer (6) and the second stirrer (8) are fixed on the transmission shaft I (9), and the third stirrer (7) is fixed on the transmission shaft II (10); The first stirrer (6) is composed of a plurality of center-holed discs (61) and a plurality of spiral belts (62) fixed on the discs (61), and the plurality of discs (61) are fixed concentrically and equidistantly on the transmission shaft I (9) through the holes in the centers; The second stirrer (8) comprises a spiral structure fixed on the transmission shaft I (9); The third stirrer (7) comprises a spiral propeller fixed on the transmission shaft II (10).

2. The final polycondensation reactor for preparing high-quality high-viscosity PA66 polymer according to claim 1, characterized in that, The diameter of the cylindrical barrel I is greater than that of the cylindrical barrel II; the feeding port (1) is arranged at the bottom of the side surface of the cylindrical barrel I away from the cylindrical barrel II, the discharging port (2) is arranged at the bottom of the side surface of the cylindrical barrel II away from the cylindrical barrel I, and the gas phase port (3) is arranged at the top of the side surface of the cylindrical barrel II away from the cylindrical barrel I.

3. A final polycondensation reactor for preparing high quality high viscosity PA66 polymer according to claim 2, characterized in that, The transmission shaft I (9) is sealingly fixed on both sides of the axial direction of the cylindrical barrel I, and extends a certain distance from the bottom surface not intersecting with the cylindrical barrel II for connecting a stirring motor; The transmission shaft II (10) is sealingly fixed on both sides of the axial direction of the cylindrical barrel II, and extends a certain distance from the bottom surface not intersecting with the cylindrical barrel I for connecting another stirring motor; The fixed position of the transmission shaft I (9) is not higher than the center line of the cylindrical barrel I, and the transmission shaft I (9) is parallel to the center line of the cylindrical barrel I; The fixed position of the transmission shaft II (10) is not higher than the center line of the cylindrical barrel II, and the transmission shaft II (10) is parallel to the center line of the cylindrical barrel II.

4. The final polycondensation reactor for preparing high-quality high-viscosity PA66 polymer according to claim 3, characterized in that, The surface of the disc (61) is divided into a plurality of hole regions (63) and a plurality of partition regions (64), the plurality of hole regions (63) and the plurality of partition regions (64) are alternately distributed along the circumferential direction of the disc (61); a plurality of spiral belts (62) are used for connecting a plurality of discs (61); the hole regions (63) on any adjacent discs (61) do not completely overlap.

5. A final polycondensation reactor for producing high quality high viscosity PA66 polymer according to claim 4, characterized in that, From the feeding port (1) to the discharging port (2), the diameter of the disc (61) is constant, and the area ratio of the hole region (63) of the disc (61) gradually increases; The distance between all the discs (61) and the inner wall surface of the cylindrical barrel I is equal.

6. A final polycondensation reactor for producing high quality high viscosity PA66 polymer according to claim 5, characterized in that, Several spiral belts (62) are fixed on the edge of the disc (61) or embedded in the partition area (64) of the disc (61) to connect several discs (61); the minimum distance between all spiral belts (62) and the inner wall surface of the cylindrical drum I is equal; the cross section of the spiral belt (62) is streamlined; the material of the spiral belt (62) is nickel-plated stainless steel alloy.

7. A final polycondensation reactor for producing high quality high viscosity PA66 polymer according to claim 6, characterized in that, The spiral structure includes several single-turn spiral blades (82), which are concentrically and vertically fixed on the transmission shaft I (9); from the feeding port (1) to the discharge port (2), the diameter of the single-turn spiral blade (82) is constant, and the pitch and the distance between adjacent single-turn spiral blades (82) are gradually reduced; the minimum distance between all single-turn spiral blades (82) and the inner wall surface of the cylindrical drum I is equal.

8. A final polycondensation reactor for producing high quality high viscosity PA66 polymer according to claim 7, characterized in that, The second stirrer (8) further includes a thin rod (81), which is fixed on the edge of the single-turn spiral blade (82) and connects all single-turn spiral blades (82); the projection of the thin rod (81) and the transmission shaft I (9) on the horizontal plane is parallel.

9. A final polycondensation reactor for producing high quality, high viscosity PA66 polymer according to claim 8, characterized in that, The spiral propeller is composed of continuous spiral blades, which are vertically fixed on the transmission shaft II (10); from the feeding port to the discharge port, the diameter of the continuous spiral blade is constant, and the pitch is gradually reduced; the minimum distance between all spiral blades and the inner wall surface of the cylindrical drum II is equal.

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