CN-121988066-A - Supercritical fluid assisted polymer post-treatment system and method

CN121988066ACN 121988066 ACN121988066 ACN 121988066ACN-121988066-A

Abstract

The invention relates to the technical field of high polymer material processing, and particularly discloses a supercritical fluid assisted polymer post-treatment system and a process. The system comprises an extraction kettle, a microfluidization processing chamber, a precision granulating die and a supercritical carbon dioxide supply unit, wherein the extraction kettle, the microfluidization processing chamber, the precision granulating die and the supercritical carbon dioxide supply unit are sequentially connected to form an integrated structure, a porous distributor is arranged in the extraction kettle, the microfluidization processing chamber is provided with a rotating blade, and the precision granulating die is provided with a micropore array structure. The process comprises the steps of conveying a polymer to an extraction kettle, extracting residual monomers by using supercritical carbon dioxide, conveying the material to a microfluidization treatment chamber, carrying out microfluidization treatment by the synergistic effect of a rotating blade and the supercritical carbon dioxide, and assisting the material to be extruded and molded by using the expansion force of the supercritical carbon dioxide through a micropore array. The invention realizes the integrated continuous treatment of high-efficiency removal of residual monomers, effective depolymerization of agglomerated particles and high-precision granulation molding, and is suitable for green high-efficiency post-treatment of PVDC, PVDF and other polymers.

Inventors

LI YAWEN
ZHOU JIANHUA
Jing Yuntian
WANG YONGBING
LIU YING
ZHAO XUETING

Assignees

金川集团股份有限公司
金川集团化工新材料有限责任公司

Dates

Publication Date: 20260508
Application Date: 20251222

Claims (12)

1. A supercritical fluid assisted polymer aftertreatment system is characterized by comprising a supercritical carbon dioxide supply unit, an extraction kettle (4), a microfluidization treatment chamber (5) and a precision granulation die (6), wherein the extraction kettle (4), the microfluidization treatment chamber (5) and the precision granulation die (6) are sequentially connected and form an integrated continuous treatment flow path, a porous distributor is arranged in the extraction kettle (4), the microfluidization treatment chamber (5) is provided with rotating blades, the rotating shafts of the rotating blades and the main flow direction of a material of the system are arranged in a non-parallel manner, the precision granulation die (6) is provided with a micropore array structure, the supercritical carbon dioxide supply unit comprises a supercritical carbon dioxide storage tank (2) and a high-pressure plunger pump (3), and the outlet of the high-pressure plunger pump (3) is respectively connected to a feed inlet of the extraction kettle (4) and a cavity of the microfluidization treatment chamber (5) through pipeline branches.
2. The supercritical fluid assisted polymer post-treatment system according to claim 1, wherein the rotating blades of the microfluidization processing chamber (5) are arranged in a multi-layer staggered manner, and the blade edges are serrated.
3. The supercritical fluid assisted polymer post-treatment system according to claim 1 or 2, characterized in that the micro-pore array of the precision granulation die (6) is of a conical pore structure, and the micro-pore inner wall is coated with a super-hydrophobic coating.
4. A supercritical fluid assisted polymer finishing system according to any of claims 1 to 3, further comprising a carbon dioxide recovery system (7), the carbon dioxide recovery system (7) comprising a condenser and a compressor connected in sequence, the inlet of the condenser being connected to the outlet of the precision pelleting die (6), the outlet of the compressor being connected to the inlet of the supercritical carbon dioxide storage tank (2) or high pressure plunger pump (3) forming a closed cycle.
5. Supercritical fluid assisted polymer finishing system according to any of claims 1 to 4 characterized in that the porous distributor of the extraction tank (4) is a multi-layer screen structure wherein the pore size of the screen decreases layer by layer and/or the opening ratio decreases layer by layer in the material flow direction.
6. The supercritical fluid assisted polymer finishing system according to any of claims 1 to 5 further comprising a polymerization reactor (1), the polymerization reactor (1) being connected to the feed inlet of the extraction reactor (4) by a screw discharger.
7. A method of supercritical fluid-assisted polymer post-treatment employing the system of any one of claims 1 to 6, comprising the steps of, in order: s1, continuously conveying a polymer material into an extraction kettle (4), and extracting a polymer through a first path of supercritical carbon dioxide, wherein the first path of supercritical carbon dioxide is dispersed through the porous distributor and passes through a polymer bed layer; S2, a microfluidization step, namely conveying the extracted material into a microfluidization treatment chamber (5), and carrying out fluidization and dispersion on the material through the synergistic effect of the second path of supercritical carbon dioxide and the rotating blades; and S3, conveying the material subjected to fluidization dispersion to a precise granulating die (6), and utilizing the expansion force of supercritical carbon dioxide contained in the material to assist extrusion forming through a micropore array.
8. The method for post-treatment of a supercritical fluid-assisted polymer according to claim 7, wherein in the step S1, the pressure of the supercritical carbon dioxide is controlled to be 20-30 mpa, the temperature is controlled to be 30-40 ℃, the flow rate of the first path of supercritical carbon dioxide is 5-60 l/h, and the extraction time is 1-3 hours.
9. The method according to claim 7 or 8, wherein in step S2, the rotation speed of the rotating blade is controlled to be 200 to 1000rpm, and the treatment time is controlled to be 10 to 30 minutes.
10. The post-treatment method of a supercritical fluid-assisted polymer according to any one of claims 7 to 9, wherein in step S3, the fine granulation die (6) has a pore diameter of 5 to 20 μm, and the deviation in the particle diameter of the obtained polymer particles is controlled within ±10 μm.
11. The method for post-treatment of polymer assisted by supercritical fluid according to any one of claims 7 to 10, further comprising a carbon dioxide recovery step, in particular, collecting carbon dioxide discharged from the granulation step, condensing, compressing, and returning to the extraction step and/or the microfluidization step for recycling.
12. The supercritical fluid-assisted polymer finishing process according to any of claims 7 to 11 wherein the polymer is polyvinylidene chloride or polyvinylidene fluoride.

Description

Supercritical fluid assisted polymer post-treatment system and method Technical Field The invention belongs to the technical field of polymer material processing, and particularly relates to a supercritical fluid assisted polymer post-treatment system and method. Background The polymer material is used as an important base material in the modern industry and has wide application in the fields of plastics, rubber, fiber and the like. In the polymer production process, a post-treatment link is important for improving the product quality, removing harmful residues and realizing accurate molding. However, the conventional post-treatment method often faces problems such as monomer residue, particle agglomeration, poor molding accuracy, and the like, and restricts the development of high performance and greenness of polymer products. In the prior art, supercritical fluids have been used in polymer processing. For example, chinese patent CN101693768a discloses a method for preparing polymer ultrafine particles using supercritical fluid, which uses supercritical fluid to treat polymer mixture, and precipitates ultrafine particles by cooling, but the method mainly focuses on particle formation, and does not involve efficient extraction of residual monomers and dispersion of particle agglomeration. Japanese patent JP6476286B2 describes a process for the preparation of polymer powders by feeding a supercritical fluid into a polymer melt and spraying it into a powder, achieving particle size control, but this technique lacks systematic post-treatment of solid polymer materials and does not integrate extraction and microfluidization processes. Chinese patent CN103347671a relates to a microporous injection molding method, in which the weight and surface characteristics of plastic parts are controlled by adjusting supercritical fluid, but the technology is mainly aimed at the injection molding process, and is not suitable for continuous post-treatment of polymerized solid materials. In general, the prior art has the defects of dispersed treatment procedures, low system integration level, high energy consumption, difficulty in realizing continuous production, accurate regulation and control and the like. Therefore, there is a strong need in the art for an efficient, environmentally friendly, accurate supercritical fluid-assisted polymer post-treatment system and method. Disclosure of Invention The invention provides a supercritical fluid auxiliary polymer aftertreatment system, which comprises a supercritical carbon dioxide supply unit, an extraction kettle, a microfluidization treatment chamber and a precision granulation die, wherein the extraction kettle, the microfluidization treatment chamber and the precision granulation die are sequentially connected and form an integrated continuous treatment flow path, a porous distributor is arranged in the extraction kettle, the microfluidization treatment chamber is provided with rotating blades, a rotating shaft of each rotating blade and a main material flow direction of the system are arranged in a non-parallel manner, the precision granulation die is provided with a micropore array structure, the supercritical carbon dioxide supply unit comprises a supercritical carbon dioxide storage tank and a high-pressure plunger pump, and an outlet of the high-pressure plunger pump is respectively connected to a feed inlet of the extraction kettle and a cavity of the microfluidization treatment chamber through pipeline branches. Further, the rotating blades of the microfluidization processing chamber adopt a multi-layer staggered arrangement mode, and the edges of the blades are in a zigzag shape. Further, the micropore array of the precision granulating die is of a conical pore structure, and the inner walls of the micropores are coated with a super-hydrophobic coating. Further, the device also comprises a carbon dioxide recovery system, wherein the carbon dioxide recovery system comprises a condenser and a compressor which are sequentially connected, an inlet of the condenser is connected with an outlet of the precision granulating mould, and an outlet of the compressor is connected with an inlet of the supercritical carbon dioxide storage tank or the high-pressure plunger pump to form closed circulation. Further, the porous distributor of the extraction kettle is of a multi-layer screen structure, wherein the pore diameter of the screen is reduced layer by layer and/or the aperture ratio is reduced layer by layer along the material flow direction. Further, the reactor also comprises a polymerization reaction kettle, and the polymerization reaction kettle is connected with a feed inlet of the extraction kettle through a spiral discharger. The invention also provides a method for post-treatment of the polymer assisted by the supercritical fluid by adopting the system, which sequentially comprises the following steps: S1, continuously conveying a polymer material into an extraction ket