Supergravity device capable of promoting foaming and devolatilization of high-viscosity polymer and application method

Abstract

The invention discloses a supergravity device capable of promoting foaming and devolatilization of a high-viscosity polymer and an application method. The supergravity device comprises a shell, a motor, a distribution disc, a rotor, an ultrasonic generation device, a liquid feeding hole, a gas outlet, a liquid discharging hole and a gas inlet, a rotating shaft of the motor penetrates through the lower surface of the shell and extends into the shell; the upper end of the rotating shaft is fixedly connected with the rotor; a packing ring is fixed on the circumference of the upper surface of the rotor, and a cavity structure in the middle of the packing ring forms a liquid inlet cavity; a distribution disc fixedly connected with the upper surface of the rotor is horizontally arranged in the liquid inlet cavity; the motor is connected with the rotor through a rotating shaft; according to the method, ultrasonic energy is introduced into a super-gravity field, liquid film updating is enhanced through the sound field cavitation and fluid disturbance effect, and multi-scale coupling of the sound field and the gravity field is achieved in combination with interface structure and wettability regulation and control, so that the gas-liquid mass transfer rate and devolatilization efficiency are remarkably improved, and the TDI removal rate is larger than or equal to 90%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of devolatilization in high polymer production, in particular, to a supergravity device for promoting foaming devolatilization of high viscosity polymer and an application method thereof. BACKGROUND

[0002] In the process of polymer synthesis and post-treatment, there are usually unreacted monomers, solvents, oligomers and other low molecular by-products in the polymer system, which are collectively referred to as volatile components. The presence of volatile components can cause abnormal molecular weight distribution of the polymer, decrease in thermal stability and degradation of mechanical properties, and even cause defects such as bubbles and precipitation in subsequent processing. Therefore, efficient devolatilization is a key link to ensure the quality, performance stability and environmental safety of polymer products.

[0003] The currently widely used devolatilization equipment mainly includes static and dynamic types. The static equipment (such as flash evaporator and falling strip devolatilization tower) relies on pressure reduction evaporation or phase equilibrium principle to separate volatile components, and has simple structure, but the disturbance and liquid film formation of the fluid are limited. When treating high viscosity polymer, the flowability is poor, the interface renewal rate is low, and local overheating and gas-liquid contact dead zone are easily formed, resulting in reduced devolatilization efficiency. The dynamic equipment (such as screw extruder, thin film evaporator and wiped film evaporator) can enhance the mass and heat transfer effect through mechanical shearing, which can improve the devolatilization performance to some extent. However, the effective gas-liquid interface is limited, and the liquid film thickness is difficult to control stably. With the increase of viscosity, the bubble generation and migration resistance increases significantly, the mass transfer rate decreases, and the system energy consumption is high and the equipment scaling is limited.

[0004] In recent years, supergravity technology has been gradually applied to the field of polymer devolatilization. Under the action of supergravity field, the liquid is dispersed into micro-scale droplets or liquid films, the liquid film surface is continuously renewed, the gas-liquid contact area is significantly increased, and the mass transfer path is shortened, thereby accelerating the migration and removal of volatile components. Compared with traditional devolatilization equipment, the supergravity devolatilization device has the advantages of short material residence time, uniform gas-liquid mixing, high mass transfer efficiency and continuous operation. However, the existing supergravity devolatilization device (such as Chinese patent ZL200710120712.7) has limitations in treating high viscosity polymer system, such as difficulty in bubble nucleation in the liquid film and low surface renewal rate, which hinders the gas-liquid mass transfer process, making it difficult for volatile components to escape efficiently, thereby significantly limiting the overall strengthening effect.

[0005] Chinese patent CN112339158A discloses a supergravity rotating bed for polymer devolatilization and granulation and an application method thereof. The supergravity rotating bed comprises a shell, a motor, a liquid inlet cavity, a multi-layer disc distributor, a rotor, a static flow guide, a granulation assembly, a discharge assembly and a gas outlet. The supergravity rotating bed can exert the advantages of the supergravity rotating bed, make the devolatilization more thorough, and make the particle size of the granulation more uniform. However, this technology still has the following defects: in the deep devolatilization of high viscosity systems, the device is difficult to effectively induce the rapid generation and separation of gas bubbles, resulting in limited terminal devolatilization efficiency. SUMMARY

[0006] The first technical problem to be solved by the present application is to provide a supergravity device that can promote foaming devolatilization of high viscosity polymers. The device overcomes the defects of existing supergravity devolatilization technology, such as slow gas-liquid interface renewal, limited bubble nucleation, and large mass transfer resistance in high viscosity systems.

[0007] The second technical problem to be solved by the present application is to provide an application method of a supergravity device that can promote foaming devolatilization of high viscosity polymers. The application method introduces ultrasonic energy into the supergravity field, strengthens liquid film renewal through cavitation and fluid disturbance of the sound field, and combines interface structure and wettability control to achieve multi-scale coupling of the sound field and the gravity field, thereby significantly improving the gas-liquid mass transfer rate and devolatilization efficiency, with a TDI removal rate of 90%.

[0008] To solve the above-mentioned first technical problem, the technical solution adopted by the application is as follows: A supergravity device that can promote foaming devolatilization of high viscosity polymers, comprising a shell, a motor, a distribution disc, a rotor, an ultrasonic generating device, a liquid inlet, a gas outlet, a liquid outlet and a gas inlet; The rotating shaft of the motor extends through the lower surface of the shell into the interior of the shell; The upper end of the rotating shaft is connected and fixed with the rotor; The upper surface of the rotor is fixed with a packing ring, and the cavity structure in the middle of the packing ring forms a liquid inlet cavity; A distribution disc fixedly connected with the upper surface of the rotor is horizontally arranged in the liquid inlet cavity; the motor is connected with the rotor through the rotating shaft; The surface of the distribution disc is provided with a micro-nano composite size rough structure and / or a surface energy gradient distribution; the upper surface of the distribution disc is opposite to the end of the liquid inlet; The ultrasonic generating device is arranged near the liquid inlet.

[0009] Preferably, the ultrasonic generating device comprises one or more ultrasonic probes arranged in a ring, radial array or lateral distribution, and the axial or radial distance between the ultrasonic probes and the distribution disc is adjustable to form a controllable cavitation region; the ultrasonic generating device has a working frequency of 10-100 kHz and a sound intensity of 3-50 W / cm2, and more preferably, the ultrasonic generating device has a working frequency of 20-40 kHz. In order to achieve better deactivation, the ultrasonic generating device can have a high sound intensity (≧20 W / cm2) and multiple frequencies.

[0010] Preferably, the micro-nano composite size rough structure comprises a ring, radial or staggered groove surface microstructure; the micro-nano composite size is 10 nm-50 μm; and the micro-nano composite size rough structure is formed by sandblasting, chemical etching, laser etching, electrodeposition, plasma treatment, coating of a low surface energy coating or a combination thereof.

[0011] Preferably, the surface energy gradient distribution gradually transitions from a liquidophilic region to a liquidophobie region or vice versa; and the surface energy gradient distribution is achieved by plasma etching, fluorosilane self-assembly or a contact angle gradient manufacturing method.

[0012] Preferably, the filler ring adopts a metal wire mesh, corrugated filler or porous foam structure with high specific surface area.

[0013] To solve the above-mentioned second technical problem, the present application adopts the first technical solution as follows: A method for promoting the foaming and devolatilization of high-viscosity polymers by using the above-mentioned supergravity device, comprising the following steps: S1. Under nitrogen protection, the high-viscosity polymer in the raw material tank is preheated to a preheating temperature and is input into the liquid inlet cavity of the supergravity device through a liquid inlet; the ultrasonic generating device continuously acts on the feeding area and the inlet area of the distribution disc to generate cavitation bubbles and acoustic flow shear, so that the material completes preliminary dispersion and viscosity reduction before entering the rotating area; S2. The internal vacuum degree of the supergravity device is maintained at 0.07-0.098 MPa by a vacuum pump, and under the coupling action of the supergravity field and the ultrasonic field, the polymer is sprayed from the liquid inlet end to the upper surface of the distribution disc, spreads along the radial direction of the distribution disc to form a thin liquid film, and the ultrasonic cavitation and acoustic flow disturbance induce microscale bubble nucleation, breakage and detachment on the surface and inside of the liquid film; the liquid further enters the filler to realize multiple dispersion and regeneration of the liquid film under the action of the heterogeneous nucleation site, so as to continuously strengthen the renewal of the gas-liquid interface and the migration of volatile components under the coupling action of the ultrasonic field and the supergravity field; S3. The polymer after devolatilization is discharged from the liquid outlet, and the volatile gas is discharged from the gas outlet and recovered by a condensation system.

[0014] Preferably, the rotating speed of the distribution disc is 0-3000 r / min; more preferably, the rotating speed of the distribution disc is 300-3000 r / min.

[0015] Preferably, in step S1, the apparent viscosity of the high-viscosity polymer ranges from 500-100000 mPa·s, preferably 2000-50000 mPa·s.

[0016] Preferably, in step S2, the temperature of the de-illumination in the supergravity device is 25-400℃; more preferably, 50-250℃.

[0017] Any range recited in the present application includes the end values and any intervening values and any ranges which have the same end values or which overlap with the same end values.

[0018] Unless otherwise specified, each raw material in the present application can be obtained by commercial purchase, and the equipment used in the present application can adopt the conventional equipment in the field or refer to the prior art in the field.

[0019] Compared with the prior art, the present application has the following beneficial effects: The present application can make the bubble nucleate rapidly, the liquid film update continuously, and the interface regenerate efficiently through the coupling effect of the sound field and the gravity field, thereby significantly improving the devolatilization rate of the high-viscosity system, and the removal rate of TDI is >=90%. The microstructure and wettability of the distribution disc and the filler surface provide a large number of heterogeneous nucleation sites, and the gas-liquid exchange efficiency is enhanced. The device structure is compact, the parameters are adjustable, the energy consumption is low, it is suitable for various polymer systems, and has good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0020] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings Figure 1 Fig. 1 is a structural schematic diagram of the supergravity devolatilization device of the present application; Figure 2 Fig. 2 is a process flow schematic diagram of removing TDI by using the supergravity devolatilization device of the present application. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the present application, the present application will be further described below with reference to the preferred embodiments and the accompanying drawings. Similar components are denoted by the same reference numerals in the drawings. Those skilled in the art should understand that the specific description below is illustrative rather than limiting, and should not limit the protection scope of the present application.

[0022] Various cross-sectional views of embodiments according to the present application are shown in the drawings. These drawings are not drawn to scale, in which certain details are shown in a somewhat exaggerated manner for the purpose of clarity and illustration, and certain other details can be omitted. The shapes and relative sizes of the various regions, layers, and the relative positions of the regions and layers shown in the drawings are shown for exemplary purposes only. Depending on the manufacturing and technical limitations or requirements, actual shapes, sizes, and relative positions of the regions / layers can deviate from what is shown in the drawings, and regions / layers having different shapes, sizes, and relative positions can be designed by those skilled in the art according to actual requirements.

[0023] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or indirectly on the other element with intervening elements present. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element with intervening elements present.

[0024] It should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", and the like, refer to the orientation or position shown in the drawings, and are used only for the purpose of convenience and brevity in describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application.

[0025] Referring to Figure 1 As an aspect of the present application, an ultra-gravity device for facilitating the foaming and devolatilization of high-viscosity polymers is shown, which includes a housing 1, a motor 2, a distribution disc 3, a rotor 4, an ultrasonic generating device 5, a liquid feed inlet 6, a gas outlet 7, a liquid outlet 8, and a gas inlet 9; The rotating shaft 21 of the motor 2 extends through the lower surface of the housing 1 into the interior of the housing 1; The upper end of the rotating shaft 21 is connected and fixed to the rotor 4; A packing ring 41 is fixed to the upper surface of the rotor 4; the cavity structure in the middle of the packing ring 41 forms a liquid inlet cavity 42; A distribution disc 3 is horizontally arranged in the liquid inlet cavity 42 and is fixedly connected to the upper surface of the rotor 4; the motor 2 is connected to the rotor 4 through the rotating shaft 21 and is used to drive the high-speed rotation of the distribution disc 3 and the rotor 4, so as to generate an ultra-gravity field in the interior of the device; a vibration-proof support mechanism (not shown in the figure) is arranged at the bottom of the motor 2 to ensure the stable operation of the system; The surface of the distribution disc 3 is subjected to a structured treatment (roughness and wettability modification) and is formed with a micro-nano composite size rough structure and / or a surface energy gradient distribution; the surface of the distribution disc is used to provide out-of-phase nucleation sites, to control the surface wettability, and to enhance the disturbance and shear renewal of the liquid film, so as to facilitate the bubble generation, detachment, and migration of volatile components; the upper surface of the distribution disc is opposite to the end of the liquid feed inlet. The ultrasonic generating device 5 is arranged near the liquid inlet 6 to generate cavitation bubbles and acoustic streaming vortices when the material enters the high gravity device, so as to intensify the liquid film disturbance and accelerate the gas-liquid interface renewal; The shell 1 is provided with a gas outlet 7 at the top for discharging the removed volatile components; the shell 1 is provided with a gas inlet 9 on the side wall, which is used to introduce inert gas or water vapor into the device to achieve stripping and devolatilization. The gas outlet 7 can form a vacuum devolatilization system with a vacuum pump to form a low-pressure environment to reduce the vaporization pressure of the volatile components; when the polymer system is not suitable for operation under high vacuum conditions, nitrogen, argon or water vapor can be introduced through the gas inlet 9 to strengthen the stripping, so as to promote the removal of volatile components at the liquid film interface, and realize the alternative or coupled operation mode of vacuum devolatilization and stripping devolatilization; the liquid outlet 8 is arranged at the bottom of the shell for discharging the polymer melt after devolatilization.

[0026] In some embodiments of the present application, the ultrasonic generating device 5 includes one or more ultrasonic probes arranged in a ring, radial array or lateral distribution, and the axial or radial distance of the ultrasonic probe from the distribution disc is adjustable to form a controllable cavitation region; the working frequency of the ultrasonic generating device is 10-100 kHz, and the acoustic intensity is 3-50 W / cm², and more preferably, the working frequency of the ultrasonic generating device is 20-40 kHz. The high gravity device of the present application forms a multi-field coupling effect under the action of ultrasonic field and high gravity field: ultrasonic cavitation promotes bubble nucleation and acoustic disturbance, and the high gravity field realizes interface renewal through liquid film shearing and dispersion, and the coupling of the two significantly improves the gas-liquid mass transfer rate.

[0027] In some embodiments of the present application, the micro-nano composite size rough structure includes a ring, radial or staggered groove surface microstructure; the micro-nano composite size is 10 nm-50 μm; the micro-nano composite size rough structure is formed by sandblasting, chemical etching, laser etching, electrodeposition, plasma treatment, coating of low surface energy coating or a combination thereof.

[0028] In some embodiments of the present application, the surface energy gradient distribution gradually transitions from a liquidophilic region to a liquidophobie region or vice versa; preferably, it is realized by plasma etching, fluorosilane self-assembly or contact angle gradient manufacturing method to promote the directional migration of bubbles or liquid filaments.

[0029] In some embodiments of the present application, the filler ring 41 adopts a metal wire mesh, corrugated filler or porous foam structure with high specific surface area, and is surface-modified to provide bubble heterogeneous nucleation sites and liquid film breaking area, so as to further expand the gas-liquid interface and improve the mass transfer rate.

[0030] Reference is made to Figure 2As shown, as another aspect of the present application, the present application is a method for promoting foaming and devolatilization of high-viscosity polymers using the above supergravity device, comprising the following steps: S1, under the condition of nitrogen protection, preheat the high-viscosity polymer in the raw material tank 200 to a preheating temperature, and input it into the liquid inlet cavity 42 of the supergravity device through the liquid inlet; the ultrasonic generating device 5 continuously acts on the inlet area and the inlet area of the distribution disc 3, generating cavitation bubbles and acoustic flow shear, so that the material completes preliminary dispersion and viscosity reduction before entering the rotating area; S2, maintain the internal vacuum degree of the supergravity device 100 at 0.07-0.098 MPa by the vacuum pump 300, under the coupling action of the supergravity field and the ultrasonic field, the polymer is sprayed from the liquid inlet end to the upper surface of the distribution disc 3, and spreads along the radial direction of the distribution disc to form a thin liquid film, and the ultrasonic cavitation and acoustic flow disturbance induce microscale bubble nucleation, fragmentation and detachment on the surface and inside of the liquid film; the liquid further enters the filler and realizes multiple dispersion and regeneration of the liquid film under the action of the heterogeneous nucleation site, so as to continuously strengthen the gas-liquid interface renewal and volatile component migration under the coupling action of the ultrasonic field and the supergravity field; S3, the polymer after devolatilization is discharged from the liquid outlet 8, and the volatile gas is discharged from the gas outlet 7 and recovered by the condensation system.

[0031] In some embodiments of the present application, in step S1, the apparent viscosity of the high-viscosity polymer ranges from 500 to 100000 mPa·s, preferably from 2000 to 50000 mPa·s.

[0032] In some embodiments of the present application, in step S2, the rotating speed of the distribution disc is 0-3000 r / min, which can be adjusted to control the liquid film thickness and gas-liquid residence time to achieve the optimal devolatilization conditions of different polymer systems; more preferably, the rotating speed of the distribution disc is 300-3000 r / min.

[0033] In some embodiments of the present application, in step S2, the devolatilization temperature in the supergravity device is 25-400℃; more preferably, it is 50-250℃. Example 1

[0034] Reference Figure 2 As shown, the method for removing TDI in polyurethane prepolymer by using the supergravity devolatilization device of the present application comprises the following steps: S1, under the condition of nitrogen protection, the polyurethane prepolymer containing about 1.0wt% TDI in the raw material tank 200 is preheated to a preheating temperature of 110℃, and then input into the liquid inlet cavity 42 of the supergravity device through the liquid inlet, and the material flow is controlled to be 50L / h; the ultrasonic generating device 5 continuously acts in the feeding area and the inlet area of the distribution disc 3, cavitation bubbles and acoustic flow shear are generated, so that the material completes preliminary dispersion and viscosity reduction before entering the rotating area; the rotating speed of the distribution disc is set to 1000r / min; the ultrasonic generating device works at an ultrasonic frequency of 20kHz, the sound intensity is 20W / cm², and the effective coupling of the sound field and the liquid film is realized in the supergravity field formed by the distribution disc and the filler; S2, the internal vacuum degree of the supergravity device 100 is maintained at 0.095MPa by the vacuum pump 300, and the internal devolatilization temperature of the supergravity device 100 is controlled at 110℃; under the coupling action of the supergravity field and the ultrasonic field, the polymer is sprayed from the liquid inlet end to the upper surface of the distribution disc 3, spreads along the radial direction of the distribution disc to form a thin liquid film, and the ultrasonic cavitation and acoustic flow disturbance induce microscale bubble nucleation, breakage and separation on the surface and inside of the liquid film; the liquid further enters the filler, realizes multiple dispersion and regeneration of the liquid film under the action of the heterogeneous nucleation site, so that the liquid film is continuously strengthened under the coupling action of the ultrasonic field and the supergravity field, and the gas-liquid interface renewal and volatile component migration are continuously strengthened; S3, the polymer after devolatilization is discharged from the liquid outlet 8, and the volatile gas is discharged from the gas outlet 7 and recovered by the condensation system.

[0035] It is detected that after the polyurethane prepolymer is treated by the device, the content of TDI in the prepolymer is significantly reduced, and the TDI removal rate can reach 90%.

[0036] The results show that, compared with the traditional supergravity devolatilization equipment, the device can obtain better devolatilization function under lower energy consumption through the synergistic action of ultrasonic cavitation and supergravity liquid film strengthening. Example 2

[0037] Example 1 is repeated, except that in step 1), the material flow is controlled to be 35L / h; the rotating speed of the distribution disc is set to 1500r / min; the sound intensity of the ultrasonic generating device is 20W / cm²; in step 2), the internal devolatilization temperature of the supergravity device 100 is controlled at 120-130℃; a small amount of inert gas (such as nitrogen) is introduced through the gas inlet in an intermittent manner to realize light stripping, further reduce the partial pressure of TDI at the interface, and promote the more complete volatilization and migration of TDI.

[0038] It is detected that after the polyurethane prepolymer is treated by the device, the content of TDI in the prepolymer is significantly reduced to ≦0.05wt%, and the TDI removal rate is ≧95%.

[0039] The results show that by increasing the rotation speed, increasing the ultrasonic intensity and assisting with stripping means, the devolatilization depth can be significantly improved, and a higher residual control level can be achieved to meet the requirements of high-end polyurethane materials for low volatile residuals. Example 3

[0040] Example 1 was repeated, except that in step 1), the material flow rate was controlled at 40 L / h; the distribution disc rotation speed was set at 1200 r / min; the ultrasonic generating device was switched to a dual-frequency mixed mode (20 kHz + 28 kHz) with a sound intensity of 35 W / cm² to enhance the sound-induced bubble formation and rupture effect; in step 2), the devolatilization temperature inside the supergravity device 100 was controlled at about 120°C; under the action of dual-frequency enhanced ultrasonic waves, different scale cavitation nuclei can be generated on the liquid film surface at the same time, promoting the rapid generation, expansion and rupture of micro-scale bubbles, and significantly accelerating the mass transfer rate of TDI.

[0041] After detection, the TDI content in the polyurethane prepolymer treated by this embodiment was significantly reduced to ≦0.05wt%, and the corresponding TDI removal rate was ≧95%.

[0042] The experimental results show that the initial TDI mass fraction in the material is about 1.0%, and after treatment under the conditions of this embodiment, the TDI residual in the discharge is reduced to ≤0.03%, and the corresponding removal rate is ≥97%; compared with the single-frequency 20 kHz, sound intensity 20 W / cm² condition, the devolatilization efficiency is increased by about 5-7%, further verifying the significant promotion effect of high sound intensity and multi-frequency collaborative ultrasonic waves on the devolatilization of high viscosity systems. Example

[0043] In order to further enhance the foaming ability of high viscosity polymer on the surface of the rotating disc, the surface microstructure of the distribution disc was modified in this embodiment to make it more easily induce the formation of initial bubble nuclei, thereby accelerating the foaming of the liquid film and the escape of volatile components. Specifically, Example 1 was repeated, except that: In step 1), the material flow rate was controlled at 50 L / h; the distribution disc rotation speed was set at 1300 r / min; the system vacuum degree was maintained at 0.096 MPa; the ultrasonic frequency and sound intensity of the ultrasonic generating device were 20 kHz and 25 W / cm², respectively; in step 2), the devolatilization temperature inside the supergravity device was controlled at about 115°C; the comparison distribution disc treatment methods included: 1) sandblasting to form rough micro-convex structures of 20-50 μm on the disc surface; or 2) laser etching to form 50-100 μm micro-grooves arranged in a staggered manner on the disc surface; the above treatments can increase the "bubble nucleation point density" of the solid surface, promote the rapid generation of a large number of micro-bubbles during the high-speed rotation of the liquid film, and significantly improve the interface renewal rate. After the disc treated by the above surface treatment was operated, the liquid film foaming capacity was observed to be enhanced: the bubble diameter became smaller and the number increased.

[0044] The experimental results show that after the treatment in the conditions of the embodiment, the TDI residue in the discharge is reduced to 0.03-0.05%, and the removal rate is greater than or equal to 95%; compared with the untreated disc, the devolatilization efficiency of the embodiment is improved by about 4-6%. The embodiment verifies that the surface microstructuring treatment of the distribution disc can effectively improve the foaming ability of the high-viscosity liquid, and is an important auxiliary means for improving the effect of supergravity devolatilization. Example 4

[0045] To verify the further improvement of the foaming devolatilization performance of the filler after the surface modification treatment on the high-viscosity polymer, in the embodiment, γ-Al2O3 microspheres activated by a silane coupling agent are used as the filler, so that a microscale rough structure is formed to enhance the liquid film disturbance. Specifically, Example 1 is repeated, and the difference lies in that: In step 1), the material flow rate is controlled to be 40 L / h; the rotation speed of the distribution disc is set to be 1200 r / min; the system vacuum degree is maintained to be 0.095-0.096 MPa; the ultrasonic frequency and acoustic intensity of the ultrasonic generating device are 20 kHz and 25 W / cm², respectively; in step 2), the internal devolatilization temperature of the supergravity device is controlled to be 115-120°C; since the modified filler has good wettability and can significantly improve the micro-turbulent intensity of the liquid film surface, the liquid spreads more quickly on the disc surface, the liquid film is thinner, and it is easier to form uniform microbubbles, thereby significantly improving the mass transfer efficiency of the gas-liquid interface.

[0046] The experimental results show that: after using the modified filler, the TDI removal rate is increased from about 91% under the condition of no filler to greater than or equal to 96%, and the residual TDI mass fraction is stably less than or equal to 0.04%, and the overall volatile matter removal effect is obviously enhanced, which fully proves the synergistic effect of the surface modified filler structure in the device. Comparative Example 1

[0047] Example 1 is repeated, and the difference lies only in that: a rotating packed bed (RPB) with a traditional structure is used, and the ultrasonic device is not configured, and the disc and the filler are both unmodified metal surfaces.

[0048] The operating conditions are: material flow rate 50 L / h, rotation speed 1000 r / min, vacuum degree 0.095 MPa, and devolatilization temperature 110°C. Under the conditions, due to the lack of acoustic cavitation, acoustic flow vortex and micro-jet driving in the system, the liquid film disturbance intensity is low, and the high-viscosity material is difficult to achieve sufficient dispersion before entering the rotating zone; at the same time, the bubble nucleation lags behind, and the detachment speed is slow, so that the interface update frequency is much lower than that of the device.

[0049] The final detection shows that the TDI residue in the discharge is about 0.12%, and the TDI removal rate is only about 88%. The results show that the traditional RPB is prone to problems such as insufficient foaming, limited mass transfer interface and limited devolatilization depth in high-viscosity systems, and its devolatilization capacity is significantly lower than that of the device of the application using ultrasonic coupling and surface structure optimization. Comparative Example 2

[0050] Example 1 is repeated, with the only difference being that: The same batch of polyurethane prepolymer is selected, and TDI devolatilization is carried out in an industrial commonly used wiped film evaporator; by increasing the operating temperature to 130℃ and the vacuum degree to 0.098MPa, deep devolatilization is attempted; the material flow rate is maintained at 50L / h; the wiped film evaporator only relies on the flow of the wiped film to form a thin layer, and when the system viscosity is high, the liquid film thickness increases, the surface renewal is limited, and the device itself does not have the functions of ultrasonic foaming, rotary intensification, and structured surface enhancement; in high-viscosity systems, bubble nucleation is difficult, and the gas-liquid interface area is limited; although the temperature and vacuum degree have been increased, the final TDI residue is still about 0.15wt%, and the removal rate is less than 85%; this result shows that relying only on the "temperature increase-deep vacuum reduction" strategy is not enough to achieve deep devolatilization of high-viscosity polymers.

[0051] In summary, the application uses the coupling effect of ultrasonic field and supergravity field to significantly intensify liquid film disturbance, bubble nucleation and interface renewal process, forming a complete multi-field coupling devolatilization system; if any structural feature (such as surface microstructure), physical field condition (such as ultrasonic frequency, sound intensity), or process parameter (such as rotation speed, liquid volume, etc.) deviates from the range set by the application, it is difficult to achieve the extremely high devolatilization efficiency and stability described in the application.

[0052] Obviously, the above examples of the application are only examples for clearly illustrating the application, and are not a limitation on the embodiments of the application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. It is impossible to exhaust all embodiments here. Any obvious changes or variations derived from the technical solutions of the application still fall within the protection scope of the application.

Claims

1. A hypergravity device for promoting foaming and devolatilization of high-viscosity polymers, characterized in that: It includes a housing, motor, distribution disc, rotor, ultrasonic generator, liquid inlet, gas outlet, liquid outlet, and gas inlet; The rotating shaft of the motor extends through the lower surface of the housing into the housing; The upper end of the rotating shaft is fixedly connected to the rotor; A packing ring is fixed on the circumference of the upper surface of the rotor, and the cavity structure in the middle of the packing ring forms a liquid inlet cavity. The liquid inlet chamber is horizontally arranged with a distribution disk fixedly connected to the upper surface of the rotor; the motor is connected to the rotor via a rotating shaft. The surface of the distribution disk is provided with a micro-nano composite-sized rough structure and / or a surface energy gradient distribution; the upper surface of the distribution disk faces the liquid inlet end; The ultrasonic generator is located near the liquid inlet.

2. The hypergravity device according to claim 1 that promotes foaming and devolatilization of high-viscosity polymers, characterized in that: The ultrasonic generator includes one or more ultrasonic probes, which are arranged in a circular, radial array, or lateral distribution spatial configuration, and their axial or radial distance from the distribution disk is adjustable. The ultrasonic generator operates at a frequency of 10-100 kHz and a sound intensity of 3-50 W / cm². More preferably, the ultrasonic generator operates at a frequency of 20-40 kHz. Most preferably, in order to achieve better deglow reduction, the ultrasonic generator operates at a high sound intensity, multi-frequency coordinated ultrasonic mode.

3. The hypergravity device according to claim 1 that promotes foaming and devolatilization of high-viscosity polymers, characterized in that: The micro-nano composite roughened structure includes annular, radial, or staggered trench surface microstructures; the micro-nano composite size is 10nm-50μm; the micro-nano composite roughened structure is formed by sandblasting, chemical etching, laser etching, electrodeposition, plasma treatment, coating with a low surface energy coating, or a combination thereof.

4. The hypergravity device according to claim 1 that promotes foaming and devolatilization of high-viscosity polymers, characterized in that: The surface energy gradient distribution gradually transitions from a hydrophilic region to a hydrophobic region or vice versa; it is achieved through plasma etching, fluorosilane self-assembly, or contact angle gradient fabrication methods.

5. The hypergravity device according to claim 1 that promotes foaming and devolatilization of high-viscosity polymers, characterized in that: The packing ring is made of high specific surface area metal wire mesh, corrugated packing or porous foam structure.

6. A method for promoting foaming and devolatilization of high-viscosity polymers using any one of the hypergravity devices described in claims 1-5, characterized in that, Includes the following steps: S1. Under nitrogen protection, the high-viscosity polymer in the raw material storage tank is preheated to the preheating temperature and fed into the liquid inlet of the supergravity device through the liquid inlet. The ultrasonic generator continuously acts in the feeding area and the distribution disk inlet area to generate cavitation bubbles and acoustic shearing, so that the material is initially dispersed and its viscosity is reduced before entering the rotating zone. S2. The vacuum level inside the hypergravity device is maintained at 0.07-0.098 MPa by a vacuum pump. Under the coupling effect of the hypergravity field and the ultrasonic field, the polymer is sprayed from the liquid inlet end onto the upper surface of the distribution disk and spreads radially along the distribution disk to form a thin liquid film. Ultrasonic cavitation and acoustic flow disturbance induce the nucleation, breakup and detachment of micro-scale bubbles on the surface and inside the liquid film. The liquid further enters the packing material, and under the action of heterogeneous nucleation sites, the liquid film is dispersed and regenerated multiple times. Thus, under the coupling effect of the ultrasonic field and the hypergravity field, the gas-liquid interface renewal and volatile component migration are continuously enhanced. S3. The polymer after devolatilization is discharged from the liquid outlet, and the volatile gas is discharged from the gas outlet and recovered by the condensation system.

7. The method for promoting foaming and devolatilization of high-viscosity polymers using the hypergravity device according to claim 6, characterized in that: In step S1, the apparent viscosity of the high-viscosity polymer is in the range of 500-100000 mPa·s, preferably 2000-50000 mPa·s.

8. The method for promoting foaming and devolatilization of high-viscosity polymers using a hypergravity device according to claim 6, characterized in that: In step S2, the rotational speed of the distribution disk is 0-3000 r / min; more preferably, the rotational speed of the distribution disk is 300-3000 r / min.

9. The method for promoting foaming and devolatilization of high-viscosity polymers using a hypergravity device according to claim 6, characterized in that: Preferably, in step S2, the descaling temperature inside the hypergravity device is 25-400℃; more preferably, it is 50-250℃.

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