Continuous single-shaft kneading reactor for final polycondensation of polyethylene naphthalate

Abstract

The invention belongs to the technical field of high polymer material synthesis equipment, and relates to a continuous single-shaft kneading reactor for final polycondensation of polyethylene naphthalate, the continuous single-shaft kneading reactor comprises a stirring paddle and a stirring cylinder, the stirring paddle comprises a stirring shaft, the stirring shaft is provided with a plurality of stirring blades extending outwards along the radial direction, and the tip part of each stirring blade is a scraper; kneading claws are arranged on the inner barrel wall of the stirring barrel, and T-shaped vertical rods of the kneading claws are inward in the radial direction; the stirring blades and the kneading claws are arranged at intervals in a staggered mode in the axial direction, and when the stirring blades rotate in the stirring barrel, the stirring blades and the kneading claws rotate mutually in the stirring barrel for kneading; through the synergistic effect of the spirally distributed stirring blades, the blade end scrapers and the kettle wall kneading claws, efficient melt conveying, kneading and surface updating are achieved, the devolatilization and mass transfer efficiency in the polyester final polycondensation process is remarkably improved, meanwhile, energy consumption is reduced, and it is ensured that the product quality is stable.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material synthesis equipment and relates to a continuous single-axis kneading reactor for final polycondensation of polyethylene naphthalate. Background Art

[0002] Polyethylene naphthalate (PEN) resin has excellent barrier properties, thermal stability and mechanical properties, and is an ideal material for electronic information, electronic packaging, optoelectronic devices and special engineering fields. PEN is usually bulk polymerized by ester exchange or direct esterification. In the final polycondensation process of polyethylene naphthalate (PEN), the core role of the reactor is to promote the surface renewal of the melt, improve the devolatilization efficiency, and enhance the mass transfer effect, thereby accelerating the polymerization reaction rate.

[0003] However, the existing continuous reaction equipment has the following technical problems:

[0004] 1. The contradiction between efficient kneading and equipment complexity. Although the traditional twin-shaft kneading reactor can improve the melt surface renewal rate and devolatilization efficiency through kneading, its structure is complex and it is easy to produce unstable factors during operation, resulting in fluctuations in product quality. At the same time, the energy consumption of twin-shaft equipment is high and the maintenance cost is high, which is not conducive to the economy of industrial application. Although the single-shaft disc reactor has a simple structure and stable operation, due to the lack of effective kneading, the surface renewal rate of the melt is low, resulting in low devolatilization and mass transfer efficiency, and it is difficult to meet the needs of efficient polymerization of high-viscosity materials.

[0005] 2. PEN melt retention and over-reaction problems. The existing single-axis reactor lacks a wall scraper, which easily causes the PEN melt to be retained on the reactor wall, resulting in over-reaction, thus affecting product quality.

[0006] 3. Dead zones inside the reactor affect product quality. During the reaction process, if there are dead zones inside the reactor, some materials will stay too long or too short, affecting the uniformity of the reaction and reducing the quality stability of the final product.

[0007] Therefore, a device or method with a simple structure and stable operation, which can improve the melt surface renewal rate and enhance the devolatilization and mass transfer efficiency, is needed to solve the above technical problems. Summary of the invention

[0008] The technical solution adopted by the present invention to solve the technical problem is: a continuous single-axis kneading reactor for final polycondensation of polyethylene naphthalate, comprising: a stirring paddle and a stirring drum, wherein the stirring drum is cylindrical;

[0009] The stirring paddle comprises a stirring shaft, which extends axially from one end of the stirring drum into the stirring drum, and a plurality of stirring blades extending radially outward are arranged on the cylindrical surface of the stirring shaft, the root of the stirring blade is a rounded trapezoidal blade, and the tip of the stirring blade is a scraper; the blade surface of the rounded trapezoidal blade is a three-dimensional spiral surface, the trapezoidal upper bottom edge of the rounded trapezoidal blade is fixedly connected to the cylindrical surface of the stirring shaft, and the trapezoidal lower bottom edge of the rounded trapezoidal blade is fixedly connected to the scraper, and the scraper is in the shape of a straight rod, the middle section of the straight rod of the scraper is connected to the middle section of the trapezoidal lower bottom edge of the rounded trapezoidal blade, and the two ends of the straight rod of the scraper extend out of the outer edge of the trapezoidal lower bottom edge of the rounded trapezoidal blade, and an angle is arranged between the length direction of the straight rod of the scraper and the trapezoidal lower bottom edge of the rounded trapezoidal blade;

[0010] The inner wall of the mixing drum is provided with a kneading claw, which is in a "T" shape. The "T"-shaped vertical rod of the kneading claw is radially inward, and the suspended end of the "T"-shaped vertical rod of the kneading claw is connected to the inner wall of the drum. The "T"-shaped horizontal rod of the kneading claw is parallel to the rotating axis of the mixing shaft.

[0011] The stirring blades are arranged alternately with the kneading claws along the axial direction, the scrapers of the stirring blades extend axially into the inner side of the cross bars of the adjacent kneading claws, and the "T"-shaped cross bars of the kneading claws extend axially into the inner side of the adjacent scrapers; when the stirring blades rotate in the mixing drum, the stirring blades and the kneading claws rotate and knead with each other in the mixing drum.

[0012] Preferably, the stirring blades are provided in plurality, and the plurality of stirring blades are arranged around the stirring shaft; the kneading claws are provided in plurality, and the plurality of kneading claws are arranged around the inner wall of the mixing drum.

[0013] More preferably, the stirring blades are provided with 2 to 6 pieces, and the stirring blades are evenly distributed around the stirring shaft; the kneading claws are provided with 7 to 16 pieces, and the kneading claws are evenly distributed around the inner wall of the mixing drum.

[0014] Preferably, the stirring blades are provided in plurality, and the plurality of stirring blades are arranged along the axial direction of the stirring shaft.

[0015] Preferably, a coupling is provided at the end of the stirring shaft.

[0016] More preferably, the coupling comprises: an inner hexagonal hole at the end of the stirring shaft which is recessed axially inward.

[0017] Preferably, the mixing drum, mixing blades and mixing shaft rotate on the same axis.

[0018] Preferably, the scraper is close to the inner cylinder wall in radial direction.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention adopts spirally distributed blades, which can not only transport the melt, ensure the continuous flow of the polyester melt in the reactor, realize continuous feeding and discharging, avoid stagnation or uneven reaction, but also improve the stirring effect.

[0021] 2. A scraper is provided at the end of the blade of the present invention to prevent the melt from staying on the kettle wall, avoid excessive reaction or material degradation, and improve the stability of product quality.

[0022] 3. The wall of the reactor of the present invention is provided with kneading claws, which cooperate with the stirring blades and scrapers to increase the surface renewal rate, enhance the devolatilization and mass transfer efficiency, reduce the dead zone, improve the reaction uniformity, accelerate the volatilization of low molecules, improve the mass transfer efficiency, and promote the polycondensation reaction rate.

[0023] 4. Compared with the double-shaft equipment, the single-shaft kneading design of the present invention simplifies the structure, improves the operation stability, and reduces energy consumption, thereby realizing a more efficient and economical polyester final polycondensation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a stereogram of a continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to the present invention;

[0025] Figure 2 is a side view of the present invention;

[0026] Figure 3 It is a schematic diagram of a stirring paddle of the present invention;

[0027] Figure 4 A top view of the stirring paddle of the present invention;

[0028] Figure 5 A three-dimensional diagram of a single set of stirring blades of the present invention;

[0029] Figure 6 It is a side view of a single set of stirring blades of the present invention;

[0030] Figure 7 A top view of a single set of stirring blades of the present invention;

[0031] Figure 8 It is a side view of the kettle wall of the present invention;

[0032] Fig. 9 A top view of a kettle wall of the present invention;

[0033] Fig.10 It is a kneading schematic diagram of the stirring blade and the kneading claws of the present invention;

[0034] Fig.11 A top view of the kneading of the stirring blade and the kneading claws of the present invention;

[0035] Fig.12It is a kneading side view of the stirring blade and kneading claws of the present invention.

[0036] In the figure, 1, stirring paddle; 2, stirring drum; 11, stirring shaft; 12, stirring blade; 13, rounded trapezoidal blade; 14, scraper; 21, inner drum wall; 22, kneading claws. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the relevant technologies in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0038] refer to Figures 1 to 12 As shown, a continuous single-axis kneading reactor for final polycondensation of polyethylene naphthalate comprises: a stirring paddle 1 and a stirring drum 2, wherein the stirring drum 2 is cylindrical;

[0039] The stirring paddle 1 includes a stirring shaft 11, which extends axially from one end of the stirring drum 2 into the stirring drum 2. A plurality of stirring blades 12 extending radially outward are arranged on the cylindrical surface of the stirring shaft 11. The root of the stirring blade 12 is a rounded trapezoidal blade 13, and the tip of the stirring blade 12 is a scraper 14. The blade surface of the rounded trapezoidal blade 13 is a three-dimensional spiral surface. The upper bottom edge of the trapezoid of the rounded trapezoidal blade 13 is fixedly connected to the cylindrical surface of the stirring shaft 11, and the lower bottom edge of the trapezoid of the rounded trapezoidal blade 13 is fixedly connected to the scraper 14. 4. The scraper 14 is in the shape of a straight rod, the middle section of the straight rod of the scraper 14 is connected to the middle of the lower trapezoidal bottom edge of the rounded trapezoidal blade 13, and the two ends of the straight rod of the scraper 14 extend out of the outer edge of the lower trapezoidal bottom edge of the rounded trapezoidal blade 13. An angle is provided between the length direction of the straight rod of the scraper 14 and the lower trapezoidal bottom edge of the rounded trapezoidal blade 13; the three-dimensional spiral curved blade surface of the rounded trapezoidal blade 13 can provide the melt with a thrust to move forward along the axial direction of the mixing drum 2, so the stirring paddle 1 can not only transport the melt to achieve continuous feeding and discharging, but also improve the stirring effect;

[0040] A kneading claw 22 is provided on the inner cylinder wall 21 of the mixing cylinder 2. The kneading claw 22 is in a "T" shape. The "T"-shaped vertical rod of the kneading claw 22 is radially inward, and the suspended end of the "T"-shaped vertical rod of the kneading claw 22 is connected to the inner cylinder wall 21. The "T"-shaped horizontal rod of the kneading claw 22 is parallel to the rotation axis of the mixing shaft 11. The "T"-shaped kneading claw 22 is relatively short, so a plurality of "T"-shaped kneading claws 22 can scrape away the melt in the gap between the outer edge of the rounded trapezoidal blade 13 and the scraper 14, and can also improve the mixing effect and reduce the dead zone.

[0041] The stirring blades 12 are arranged alternately with the kneading claws 22 along the axial direction, and the scrapers 14 of the stirring blades 12 extend into the inner side of the cross bars of the adjacent kneading claws 22 along the axial direction, and the "T"-shaped cross bars of the kneading claws 22 extend into the inner side of the adjacent scrapers 14 along the axial direction;

[0042] When the stirring paddle 1 rotates in the stirring drum 2, the stirring blade 12 and the kneading claws 22 rotate and knead with each other in the stirring drum 2; when the stirring blade 12 and the kneading claws 22 rotate and knead, the kneading claws 22, the stirring paddle 12 and the scraper 14 work together to increase the surface renewal rate, enhance the devolatilization and mass transfer efficiency, and at the same time reduce the dead zone and improve the reaction uniformity.

[0043] Furthermore, the stirring blades 12 are provided in plurality, and the plurality of stirring blades 12 are arranged around the stirring shaft 11 ; the kneading claws 22 are provided in plurality, and the plurality of kneading claws 22 are arranged around the inner wall of the mixing drum 2 .

[0044] Furthermore, the number of stirring blades 12 is 2 to 6, and the stirring blades 12 are evenly distributed around the stirring shaft 11 ; the number of kneading claws 22 is 7 to 16, and the kneading claws 22 are evenly distributed around the inner wall of the mixing drum 2 .

[0045] Furthermore, the stirring blades 12 are provided in plurality, and the plurality of stirring blades 12 are arranged along the axial direction of the stirring shaft 11 .

[0046] Furthermore, a coupling is provided at the end of the stirring shaft 11.

[0047] Furthermore, the coupling includes: an inner hexagonal hole at the end of the stirring shaft 11 which is recessed inwardly along the axial direction.

[0048] Furthermore, the mixing drum 2 , the mixing blades 12 and the mixing shaft 11 rotate on the same axis.

[0049] Furthermore, the scraper 14 is close to the inner cylinder wall 21 in the radial direction.

[0050] In summary, the present invention realizes efficient melt conveying, kneading and surface renewal through the synergistic effect of the spirally distributed stirring blades, the blade end scrapers and the kettle wall kneading claws, significantly improves the devolatilization and mass transfer efficiency in the polyester final polycondensation process, while reducing energy consumption and ensuring stable product quality. Compared with the traditional double-shaft reactor, the present invention simplifies the equipment structure, reduces maintenance costs, and improves the economy and feasibility of industrial application while maintaining efficient kneading.

[0051] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate, characterized in that: include: A stirring paddle (1) and a stirring drum (2), wherein the stirring drum (2) is cylindrical; The stirring paddle (1) comprises a stirring shaft (11), the stirring shaft (11) extending axially from one end of the stirring drum (2) into the stirring drum (2), a plurality of stirring blades (12) extending radially outward are provided on the cylindrical surface of the stirring shaft (11), the root of the stirring blade (12) is a rounded trapezoidal blade (13), and the tip of the stirring blade (12) is a scraper (14); the blade surface of the rounded trapezoidal blade (13) is a three-dimensional spiral surface, and the trapezoidal upper base of the rounded trapezoidal blade (13) is The cylindrical surface of the stirring shaft (11) is fixedly connected, and the trapezoidal lower bottom edge of the rounded trapezoidal blade (13) is fixedly connected to the scraper (14); the scraper (14) is in the shape of a straight rod; the middle section of the straight rod of the scraper (14) is connected to the middle section of the trapezoidal lower bottom edge of the rounded trapezoidal blade (13); both ends of the straight rod of the scraper (14) extend out of the outer edge of the trapezoidal lower bottom edge of the rounded trapezoidal blade (13); and an angle is provided between the length direction of the straight rod of the scraper (14) and the trapezoidal lower bottom edge of the rounded trapezoidal blade (13); The inner cylinder wall (21) of the mixing cylinder (2) is provided with a kneading claw (22), the kneading claw (22) is in a "T" shape, the "T"-shaped vertical rod of the kneading claw (22) is radially inward, the end of the "T"-shaped vertical rod of the kneading claw (22) is connected to the inner cylinder wall (21), and the "T"-shaped horizontal rod of the kneading claw (22) is parallel to the rotation axis of the mixing shaft (11); The stirring blades (12) are arranged alternately with the kneading claws (22) along the axial direction, the scrapers (14) of the stirring blades (12) extend into the inner side of the cross bars of the adjacent kneading claws (22) along the axial direction, and the "T"-shaped cross bars of the kneading claws (22) extend into the inner side of the adjacent scrapers (14) along the axial direction; When the stirring paddle (1) rotates in the stirring drum (2), the stirring blade (12) and the kneading claw (22) rotate and knead with each other in the stirring drum (2).

2. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 1, characterized in that: The stirring blades (12) are provided in plurality, and the plurality of stirring blades (12) are arranged around the stirring shaft (11); the kneading claws (22) are provided in plurality, and the plurality of kneading claws (22) are arranged around the inner wall of the cylinder of the stirring cylinder (2).

3. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 2, characterized in that: The number of stirring blades (12) is 2 to 6, and the stirring blades (12) are evenly distributed around the stirring shaft (11); the number of kneading claws (22) is 7 to 16, and the kneading claws (22) are evenly distributed around the inner wall of the mixing drum (2).

4. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 1, characterized in that: The stirring blades (12) are provided in plurality, and the plurality of stirring blades (12) are arranged along the axial direction of the stirring shaft (11).

5. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 1, characterized in that: A coupling is provided at the end of the stirring shaft (11).

6. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 5, characterized in that: The coupling comprises: an inner hexagonal hole at the end of the stirring shaft (11) which is recessed inwardly along the axial direction.

7. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 1, characterized in that: The stirring drum (2), the stirring blades (12) and the stirring shaft (11) rotate on the same axis.

8. The continuous uniaxial kneading reactor for final polycondensation of polyethylene naphthalate according to claim 1, characterized in that: The scraper (14) is radially close to the inner cylinder wall (21).

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